diff options
Diffstat (limited to 'contrib/gcc/doc/invoke.texi')
| -rw-r--r-- | contrib/gcc/doc/invoke.texi | 2948 |
1 files changed, 1881 insertions, 1067 deletions
diff --git a/contrib/gcc/doc/invoke.texi b/contrib/gcc/doc/invoke.texi index 62785ff..d69d896 100644 --- a/contrib/gcc/doc/invoke.texi +++ b/contrib/gcc/doc/invoke.texi @@ -9,7 +9,7 @@ Copyright @copyright{} 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document -under the terms of the GNU Free Documentation License, Version 1.1 or +under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with the Invariant Sections being ``GNU General Public License'' and ``Funding Free Software'', the Front-Cover texts being (a) (see below), and with @@ -66,7 +66,6 @@ for contributors to GCC@. @cindex options, GCC command @c man begin DESCRIPTION - When you invoke GCC, it normally does preprocessing, compilation, assembly and linking. The ``overall options'' allow you to stop this process at an intermediate stage. For example, the @option{-c} option @@ -155,16 +154,14 @@ in the following sections. @table @emph @item Overall Options @xref{Overall Options,,Options Controlling the Kind of Output}. -@gccoptlist{ --c -S -E -o @var{file} -pipe -pass-exit-codes -x @var{language} @gol --v -### --help --target-help --version} +@gccoptlist{-c -S -E -o @var{file} -pipe -pass-exit-codes @gol +-x @var{language} -v -### --help --target-help --version} @item C Language Options @xref{C Dialect Options,,Options Controlling C Dialect}. -@gccoptlist{ --ansi -std=@var{standard} -aux-info @var{filename} @gol --fno-asm -fno-builtin -fno-builtin-@var{function} @gol --fhosted -ffreestanding @gol +@gccoptlist{-ansi -std=@var{standard} -aux-info @var{filename} @gol +-fno-asm -fno-builtin -fno-builtin-@var{function} @gol +-fhosted -ffreestanding -fms-extensions @gol -trigraphs -no-integrated-cpp -traditional -traditional-cpp @gol -fallow-single-precision -fcond-mismatch @gol -fsigned-bitfields -fsigned-char @gol @@ -173,9 +170,8 @@ in the following sections. @item C++ Language Options @xref{C++ Dialect Options,,Options Controlling C++ Dialect}. -@gccoptlist{ --fno-access-control -fcheck-new -fconserve-space @gol --fno-const-strings -fdollars-in-identifiers @gol +@gccoptlist{-fabi-version=@var{n} -fno-access-control -fcheck-new @gol +-fconserve-space -fno-const-strings -fdollars-in-identifiers @gol -fno-elide-constructors @gol -fno-enforce-eh-specs -fexternal-templates @gol -falt-external-templates @gol @@ -187,7 +183,7 @@ in the following sections. -fno-optional-diags -fpermissive @gol -frepo -fno-rtti -fstats -ftemplate-depth-@var{n} @gol -fuse-cxa-atexit -fvtable-gc -fno-weak -nostdinc++ @gol --fno-default-inline -Wabi -Wctor-dtor-privacy @gol +-fno-default-inline -Wabi -Wctor-dtor-privacy @gol -Wnon-virtual-dtor -Wreorder @gol -Weffc++ -Wno-deprecated @gol -Wno-non-template-friend -Wold-style-cast @gol @@ -196,61 +192,58 @@ in the following sections. @item Objective-C Language Options @xref{Objective-C Dialect Options,,Options Controlling Objective-C Dialect}. -@gccoptlist{ --fconstant-string-class=@var{class-name} @gol +@gccoptlist{-fconstant-string-class=@var{class-name} @gol -fgnu-runtime -fnext-runtime -gen-decls @gol --Wno-protocol -Wselector} +-Wno-protocol -Wselector -Wundeclared-selector} @item Language Independent Options @xref{Language Independent Options,,Options to Control Diagnostic Messages Formatting}. -@gccoptlist{ --fmessage-length=@var{n} @gol +@gccoptlist{-fmessage-length=@var{n} @gol -fdiagnostics-show-location=@r{[}once@r{|}every-line@r{]}} @item Warning Options @xref{Warning Options,,Options to Request or Suppress Warnings}. -@gccoptlist{ --fsyntax-only -pedantic -pedantic-errors @gol --w -W -Wall -Waggregate-return @gol +@gccoptlist{-fsyntax-only -pedantic -pedantic-errors @gol +-w -W -Wall -Waggregate-return @gol -Wcast-align -Wcast-qual -Wchar-subscripts -Wcomment @gol -Wconversion -Wno-deprecated-declarations @gol --Wdisabled-optimization -Wdiv-by-zero -Werror @gol +-Wdisabled-optimization -Wno-div-by-zero -Werror @gol -Wfloat-equal -Wformat -Wformat=2 @gol -Wformat-nonliteral -Wformat-security @gol -Wimplicit -Wimplicit-int @gol -Wimplicit-function-declaration @gol -Werror-implicit-function-declaration @gol --Wimport -Winline @gol +-Wimport -Winline -Wno-endif-labels @gol -Wlarger-than-@var{len} -Wlong-long @gol -Wmain -Wmissing-braces @gol -Wmissing-format-attribute -Wmissing-noreturn @gol --Wmultichar -Wno-format-extra-args -Wno-format-y2k @gol --Wno-import -Wpacked -Wpadded @gol +-Wno-multichar -Wno-format-extra-args -Wno-format-y2k @gol +-Wno-import -Wnonnull -Wpacked -Wpadded @gol -Wparentheses -Wpointer-arith -Wredundant-decls @gol -Wreturn-type -Wsequence-point -Wshadow @gol --Wsign-compare -Wswitch -Wsystem-headers @gol --Wtrigraphs -Wundef -Wuninitialized @gol +-Wsign-compare -Wstrict-aliasing @gol +-Wswitch -Wswitch-default -Wswitch-enum @gol +-Wsystem-headers -Wtrigraphs -Wundef -Wuninitialized @gol -Wunknown-pragmas -Wunreachable-code @gol -Wunused -Wunused-function -Wunused-label -Wunused-parameter @gol -Wunused-value -Wunused-variable -Wwrite-strings} @item C-only Warning Options -@gccoptlist{ --Wbad-function-cast -Wmissing-declarations @gol +@gccoptlist{-Wbad-function-cast -Wmissing-declarations @gol -Wmissing-prototypes -Wnested-externs @gol -Wstrict-prototypes -Wtraditional} @item Debugging Options @xref{Debugging Options,,Options for Debugging Your Program or GCC}. -@gccoptlist{ --d@var{letters} -dumpspecs -dumpmachine -dumpversion @gol --fdump-unnumbered -fdump-translation-unit@r{[}-@var{n}@r{]} @gol +@gccoptlist{-d@var{letters} -dumpspecs -dumpmachine -dumpversion @gol +-fdump-unnumbered -fdump-translation-unit@r{[}-@var{n}@r{]} @gol -fdump-class-hierarchy@r{[}-@var{n}@r{]} @gol --fdump-tree-original@r{[}-@var{n}@r{]} -fdump-tree-optimized@r{[}-@var{n}@r{]} @gol +-fdump-tree-original@r{[}-@var{n}@r{]} @gol +-fdump-tree-optimized@r{[}-@var{n}@r{]} @gol -fdump-tree-inlined@r{[}-@var{n}@r{]} @gol --fmem-report -fpretend-float @gol --fprofile-arcs -fsched-verbose=@var{n} @gol --ftest-coverage -ftime-report @gol +-feliminate-dwarf2-dups -fmem-report @gol +-fprofile-arcs -frandom-seed=@var{n} @gol +-fsched-verbose=@var{n} -ftest-coverage -ftime-report @gol -g -g@var{level} -gcoff -gdwarf -gdwarf-1 -gdwarf-1+ -gdwarf-2 @gol -ggdb -gstabs -gstabs+ -gvms -gxcoff -gxcoff+ @gol -p -pg -print-file-name=@var{library} -print-libgcc-file-name @gol @@ -260,40 +253,41 @@ in the following sections. @item Optimization Options @xref{Optimize Options,,Options that Control Optimization}. -@gccoptlist{ --falign-functions=@var{n} -falign-jumps=@var{n} @gol +@gccoptlist{-falign-functions=@var{n} -falign-jumps=@var{n} @gol -falign-labels=@var{n} -falign-loops=@var{n} @gol --fbounds-check @gol --fbranch-probabilities -fcaller-saves -fcprop-registers @gol +-fbranch-probabilities -fcaller-saves -fcprop-registers @gol -fcse-follow-jumps -fcse-skip-blocks -fdata-sections @gol -fdelayed-branch -fdelete-null-pointer-checks @gol -fexpensive-optimizations -ffast-math -ffloat-store @gol -fforce-addr -fforce-mem -ffunction-sections @gol --fgcse -fgcse-lm -fgcse-sm @gol +-fgcse -fgcse-lm -fgcse-sm -floop-optimize -fcrossjumping @gol +-fif-conversion -fif-conversion2 @gol -finline-functions -finline-limit=@var{n} -fkeep-inline-functions @gol -fkeep-static-consts -fmerge-constants -fmerge-all-constants @gol --fmove-all-movables -fno-branch-count-reg @gol +-fmove-all-movables -fnew-ra -fno-branch-count-reg @gol -fno-default-inline -fno-defer-pop @gol -fno-function-cse -fno-guess-branch-probability @gol -fno-inline -fno-math-errno -fno-peephole -fno-peephole2 @gol --funsafe-math-optimizations -fno-trapping-math @gol +-funsafe-math-optimizations -ffinite-math-only @gol +-fno-trapping-math -fno-zero-initialized-in-bss @gol -fomit-frame-pointer -foptimize-register-move @gol -foptimize-sibling-calls -fprefetch-loop-arrays @gol --freduce-all-givs -fregmove -frename-registers @gol +-freduce-all-givs -fregmove -frename-registers @gol +-freorder-blocks -freorder-functions @gol -frerun-cse-after-loop -frerun-loop-opt @gol -fschedule-insns -fschedule-insns2 @gol --fno-sched-interblock -fno-sched-spec @gol --fsched-spec-load -fsched-spec-load-dangerous @gol --fsingle-precision-constant -fssa -fssa-ccp -fssa-dce @gol --fstrength-reduce -fstrict-aliasing -fthread-jumps @gol --ftrapv -funroll-all-loops -funroll-loops @gol ---param @var{name}=@var{value} +-fno-sched-interblock -fno-sched-spec -fsched-spec-load @gol +-fsched-spec-load-dangerous -fsignaling-nans @gol +-fsingle-precision-constant -fssa -fssa-ccp -fssa-dce @gol +-fstrength-reduce -fstrict-aliasing -ftracer -fthread-jumps @gol +-funroll-all-loops -funroll-loops @gol +--param @var{name}=@var{value} @gol -O -O0 -O1 -O2 -O3 -Os} @item Preprocessor Options @xref{Preprocessor Options,,Options Controlling the Preprocessor}. -@gccoptlist{ --$ -A@var{question}=@var{answer} -A-@var{question}@r{[}=@var{answer}@r{]} @gol +@gccoptlist{-$ -A@var{question}=@var{answer} @gol +-A-@var{question}@r{[}=@var{answer}@r{]} @gol -C -dD -dI -dM -dN @gol -D@var{macro}@r{[}=@var{defn}@r{]} -E -H @gol -idirafter @var{dir} @gol @@ -305,13 +299,11 @@ in the following sections. @item Assembler Option @xref{Assembler Options,,Passing Options to the Assembler}. -@gccoptlist{ --Wa,@var{option}} +@gccoptlist{-Wa,@var{option}} @item Linker Options @xref{Link Options,,Options for Linking}. -@gccoptlist{ -@var{object-file-name} -l@var{library} @gol +@gccoptlist{@var{object-file-name} -l@var{library} @gol -nostartfiles -nodefaultlibs -nostdlib @gol -s -static -static-libgcc -shared -shared-libgcc -symbolic @gol -Wl,@var{option} -Xlinker @var{option} @gol @@ -319,37 +311,32 @@ in the following sections. @item Directory Options @xref{Directory Options,,Options for Directory Search}. -@gccoptlist{ --B@var{prefix} -I@var{dir} -I- -L@var{dir} -specs=@var{file}} +@gccoptlist{-B@var{prefix} -I@var{dir} -I- -L@var{dir} -specs=@var{file}} @item Target Options @c I wrote this xref this way to avoid overfull hbox. -- rms @xref{Target Options}. -@gccoptlist{ --b @var{machine} -V @var{version}} +@gccoptlist{-V @var{version} -b @var{machine}} @item Machine Dependent Options @xref{Submodel Options,,Hardware Models and Configurations}. @emph{M680x0 Options} -@gccoptlist{ --m68000 -m68020 -m68020-40 -m68020-60 -m68030 -m68040 @gol +@gccoptlist{-m68000 -m68020 -m68020-40 -m68020-60 -m68030 -m68040 @gol -m68060 -mcpu32 -m5200 -m68881 -mbitfield -mc68000 -mc68020 @gol -mfpa -mnobitfield -mrtd -mshort -msoft-float -mpcrel @gol -malign-int -mstrict-align} @emph{M68hc1x Options} -@gccoptlist{ --m6811 -m6812 -m68hc11 -m68hc12 @gol --mauto-incdec -mshort -msoft-reg-count=@var{count}} +@gccoptlist{-m6811 -m6812 -m68hc11 -m68hc12 -m68hcs12 @gol +-mauto-incdec -minmax -mlong-calls -mshort @gol +-msoft-reg-count=@var{count}} @emph{VAX Options} -@gccoptlist{ --mg -mgnu -munix} +@gccoptlist{-mg -mgnu -munix} @emph{SPARC Options} -@gccoptlist{ --mcpu=@var{cpu-type} @gol +@gccoptlist{-mcpu=@var{cpu-type} @gol -mtune=@var{cpu-type} @gol -mcmodel=@var{code-model} @gol -m32 -m64 @gol @@ -362,25 +349,8 @@ in the following sections. -msoft-float -msoft-quad-float -msparclite -mstack-bias @gol -msupersparc -munaligned-doubles -mv8} -@emph{Convex Options} -@gccoptlist{ --mc1 -mc2 -mc32 -mc34 -mc38 @gol --margcount -mnoargcount @gol --mlong32 -mlong64 @gol --mvolatile-cache -mvolatile-nocache} - -@emph{AMD29K Options} -@gccoptlist{ --m29000 -m29050 -mbw -mnbw -mdw -mndw @gol --mlarge -mnormal -msmall @gol --mkernel-registers -mno-reuse-arg-regs @gol --mno-stack-check -mno-storem-bug @gol --mreuse-arg-regs -msoft-float -mstack-check @gol --mstorem-bug -muser-registers} - @emph{ARM Options} -@gccoptlist{ --mapcs-frame -mno-apcs-frame @gol +@gccoptlist{-mapcs-frame -mno-apcs-frame @gol -mapcs-26 -mapcs-32 @gol -mapcs-stack-check -mno-apcs-stack-check @gol -mapcs-float -mno-apcs-float @gol @@ -392,7 +362,6 @@ in the following sections. -mthumb-interwork -mno-thumb-interwork @gol -mcpu=@var{name} -march=@var{name} -mfpe=@var{name} @gol -mstructure-size-boundary=@var{n} @gol --mbsd -mxopen -mno-symrename @gol -mabort-on-noreturn @gol -mlong-calls -mno-long-calls @gol -msingle-pic-base -mno-single-pic-base @gol @@ -401,26 +370,22 @@ in the following sections. -mpoke-function-name @gol -mthumb -marm @gol -mtpcs-frame -mtpcs-leaf-frame @gol --mcaller-super-interworking -mcallee-super-interworking } +-mcaller-super-interworking -mcallee-super-interworking} @emph{MN10200 Options} -@gccoptlist{ --mrelax} +@gccoptlist{-mrelax} @emph{MN10300 Options} -@gccoptlist{ --mmult-bug -mno-mult-bug @gol +@gccoptlist{-mmult-bug -mno-mult-bug @gol -mam33 -mno-am33 @gol -mno-crt0 -mrelax} @emph{M32R/D Options} -@gccoptlist{ --m32rx -m32r -mcode-model=@var{model-type} -msdata=@var{sdata-type} @gol --G @var{num}} +@gccoptlist{-m32rx -m32r -mcode-model=@var{model-type} @gol +-msdata=@var{sdata-type} -G @var{num}} @emph{M88K Options} -@gccoptlist{ --m88000 -m88100 -m88110 -mbig-pic @gol +@gccoptlist{-m88000 -m88100 -m88110 -mbig-pic @gol -mcheck-zero-division -mhandle-large-shift @gol -midentify-revision -mno-check-zero-division @gol -mno-ocs-debug-info -mno-ocs-frame-position @gol @@ -432,12 +397,11 @@ in the following sections. -mversion-03.00 -mwarn-passed-structs} @emph{RS/6000 and PowerPC Options} -@gccoptlist{ --mcpu=@var{cpu-type} @gol +@gccoptlist{-mcpu=@var{cpu-type} @gol -mtune=@var{cpu-type} @gol -mpower -mno-power -mpower2 -mno-power2 @gol -mpowerpc -mpowerpc64 -mno-powerpc @gol --maltivec -mno-altivec @gol +-maltivec -mno-altivec @gol -mpowerpc-gpopt -mno-powerpc-gpopt @gol -mpowerpc-gfxopt -mno-powerpc-gfxopt @gol -mnew-mnemonics -mold-mnemonics @gol @@ -448,24 +412,46 @@ in the following sections. -mfused-madd -mno-fused-madd -mbit-align -mno-bit-align @gol -mstrict-align -mno-strict-align -mrelocatable @gol -mno-relocatable -mrelocatable-lib -mno-relocatable-lib @gol --mtoc -mno-toc -mlittle -mlittle-endian -mbig -mbig-endian @gol --mcall-aix -mcall-sysv -mcall-netbsd @gol --maix-struct-return -msvr4-struct-return @gol --mabi=altivec -mabi=no-altivec @gol +-mtoc -mno-toc -mlittle -mlittle-endian -mbig -mbig-endian @gol +-mcall-aix -mcall-sysv -mcall-netbsd @gol +-maix-struct-return -msvr4-struct-return @gol +-mabi=altivec -mabi=no-altivec @gol +-mabi=spe -mabi=no-spe @gol +-misel=yes -misel=no @gol -mprototype -mno-prototype @gol --msim -mmvme -mads -myellowknife -memb -msdata @gol --msdata=@var{opt} -mvxworks -G @var{num} -pthread} +-msim -mmvme -mads -myellowknife -memb -msdata @gol +-msdata=@var{opt} -mvxworks -mwindiss -G @var{num} -pthread} -@emph{RT Options} +@emph{Darwin Options} @gccoptlist{ --mcall-lib-mul -mfp-arg-in-fpregs -mfp-arg-in-gregs @gol +-all_load -allowable_client -arch -arch_errors_fatal @gol +-arch_only -bind_at_load -bundle -bundle_loader @gol +-client_name -compatibility_version -current_version @gol +-dependency-file -dylib_file -dylinker_install_name @gol +-dynamic -dynamiclib -exported_symbols_list @gol +-filelist -flat_namespace -force_cpusubtype_ALL @gol +-force_flat_namespace -headerpad_max_install_names @gol +-image_base -init -install_name -keep_private_externs @gol +-multi_module -multiply_defined -multiply_defined_unused @gol +-noall_load -nomultidefs -noprebind -noseglinkedit @gol +-pagezero_size -prebind -prebind_all_twolevel_modules @gol +-private_bundle -read_only_relocs -sectalign @gol +-sectobjectsymbols -whyload -seg1addr @gol +-sectcreate -sectobjectsymbols -sectorder @gol +-seg_addr_table -seg_addr_table_filename -seglinkedit @gol +-segprot -segs_read_only_addr -segs_read_write_addr @gol +-single_module -static -sub_library -sub_umbrella @gol +-twolevel_namespace -umbrella -undefined @gol +-unexported_symbols_list -weak_reference_mismatches -whatsloaded} + +@emph{RT Options} +@gccoptlist{-mcall-lib-mul -mfp-arg-in-fpregs -mfp-arg-in-gregs @gol -mfull-fp-blocks -mhc-struct-return -min-line-mul @gol -mminimum-fp-blocks -mnohc-struct-return} @emph{MIPS Options} -@gccoptlist{ --mabicalls -march=@var{cpu-type} -mtune=@var{cpu=type} @gol --mcpu=@var{cpu-type} -membedded-data -muninit-const-in-rodata @gol +@gccoptlist{-mabicalls -march=@var{cpu-type} -mtune=@var{cpu=type} @gol +-mcpu=@var{cpu-type} -membedded-data -muninit-const-in-rodata @gol -membedded-pic -mfp32 -mfp64 -mfused-madd -mno-fused-madd @gol -mgas -mgp32 -mgp64 @gol -mgpopt -mhalf-pic -mhard-float -mint64 -mips1 @gol @@ -478,39 +464,39 @@ in the following sections. -m4650 -msingle-float -mmad @gol -mstats -EL -EB -G @var{num} -nocpp @gol -mabi=32 -mabi=n32 -mabi=64 -mabi=eabi @gol --mfix7000 -mno-crt0 -mflush-func=@var{func} -mno-flush-func} +-mfix7000 -mno-crt0 -mflush-func=@var{func} -mno-flush-func @gol +-mbranch-likely -mno-branch-likely} @emph{i386 and x86-64 Options} -@gccoptlist{ --mcpu=@var{cpu-type} -march=@var{cpu-type} -mfpmath=@var{unit} @gol --masm=@var{dialect} -mno-fancy-math-387 @gol +@gccoptlist{-mcpu=@var{cpu-type} -march=@var{cpu-type} @gol +-mfpmath=@var{unit} -masm=@var{dialect} -mno-fancy-math-387 @gol -mno-fp-ret-in-387 -msoft-float -msvr3-shlib @gol -mno-wide-multiply -mrtd -malign-double @gol -mpreferred-stack-boundary=@var{num} @gol --mmmx -msse -msse2 -m3dnow @gol +-mmmx -msse -msse2 -m3dnow @gol -mthreads -mno-align-stringops -minline-all-stringops @gol -mpush-args -maccumulate-outgoing-args -m128bit-long-double @gol -m96bit-long-double -mregparm=@var{num} -momit-leaf-frame-pointer @gol -mno-red-zone@gol -mcmodel=@var{code-model} @gol --m32 -m64} +-m32 -m64} @emph{HPPA Options} -@gccoptlist{ --march=@var{architecture-type} @gol +@gccoptlist{-march=@var{architecture-type} @gol -mbig-switch -mdisable-fpregs -mdisable-indexing @gol --mfast-indirect-calls -mgas -mjump-in-delay @gol +-mfast-indirect-calls -mgas -mgnu-ld -mhp-ld @gol +-mjump-in-delay -mlinker-opt -mlong-calls @gol -mlong-load-store -mno-big-switch -mno-disable-fpregs @gol -mno-disable-indexing -mno-fast-indirect-calls -mno-gas @gol -mno-jump-in-delay -mno-long-load-store @gol -mno-portable-runtime -mno-soft-float @gol -mno-space-regs -msoft-float -mpa-risc-1-0 @gol -mpa-risc-1-1 -mpa-risc-2-0 -mportable-runtime @gol --mschedule=@var{cpu-type} -mspace-regs} +-mschedule=@var{cpu-type} -mspace-regs -msio -mwsio @gol +-nolibdld -static -threads} @emph{Intel 960 Options} -@gccoptlist{ --m@var{cpu-type} -masm-compat -mclean-linkage @gol +@gccoptlist{-m@var{cpu-type} -masm-compat -mclean-linkage @gol -mcode-align -mcomplex-addr -mleaf-procedures @gol -mic-compat -mic2.0-compat -mic3.0-compat @gol -mintel-asm -mno-clean-linkage -mno-code-align @gol @@ -520,8 +506,7 @@ in the following sections. -mtail-call} @emph{DEC Alpha Options} -@gccoptlist{ --mno-fp-regs -msoft-float -malpha-as -mgas @gol +@gccoptlist{-mno-fp-regs -msoft-float -malpha-as -mgas @gol -mieee -mieee-with-inexact -mieee-conformant @gol -mfp-trap-mode=@var{mode} -mfp-rounding-mode=@var{mode} @gol -mtrap-precision=@var{mode} -mbuild-constants @gol @@ -532,111 +517,96 @@ in the following sections. -mmemory-latency=@var{time}} @emph{DEC Alpha/VMS Options} -@gccoptlist{ --mvms-return-codes} - -@emph{Clipper Options} -@gccoptlist{ --mc300 -mc400} +@gccoptlist{-mvms-return-codes} @emph{H8/300 Options} -@gccoptlist{ --mrelax -mh -ms -mint32 -malign-300} +@gccoptlist{-mrelax -mh -ms -mn -mint32 -malign-300} @emph{SH Options} -@gccoptlist{ --m1 -m2 -m3 -m3e @gol +@gccoptlist{-m1 -m2 -m3 -m3e @gol -m4-nofpu -m4-single-only -m4-single -m4 @gol --m5-64media -m5-64media-nofpu @gol --m5-32media -m5-32media-nofpu @gol --m5-compact -m5-compact-nofpu @gol +-m5-64media -m5-64media-nofpu @gol +-m5-32media -m5-32media-nofpu @gol +-m5-compact -m5-compact-nofpu @gol -mb -ml -mdalign -mrelax @gol -mbigtable -mfmovd -mhitachi -mnomacsave @gol -mieee -misize -mpadstruct -mspace @gol -mprefergot -musermode} @emph{System V Options} -@gccoptlist{ --Qy -Qn -YP,@var{paths} -Ym,@var{dir}} +@gccoptlist{-Qy -Qn -YP,@var{paths} -Ym,@var{dir}} @emph{ARC Options} -@gccoptlist{ --EB -EL @gol +@gccoptlist{-EB -EL @gol -mmangle-cpu -mcpu=@var{cpu} -mtext=@var{text-section} @gol -mdata=@var{data-section} -mrodata=@var{readonly-data-section}} @emph{TMS320C3x/C4x Options} -@gccoptlist{ --mcpu=@var{cpu} -mbig -msmall -mregparm -mmemparm @gol +@gccoptlist{-mcpu=@var{cpu} -mbig -msmall -mregparm -mmemparm @gol -mfast-fix -mmpyi -mbk -mti -mdp-isr-reload @gol -mrpts=@var{count} -mrptb -mdb -mloop-unsigned @gol -mparallel-insns -mparallel-mpy -mpreserve-float} @emph{V850 Options} -@gccoptlist{ --mlong-calls -mno-long-calls -mep -mno-ep @gol +@gccoptlist{-mlong-calls -mno-long-calls -mep -mno-ep @gol -mprolog-function -mno-prolog-function -mspace @gol -mtda=@var{n} -msda=@var{n} -mzda=@var{n} @gol +-mapp-regs -mno-app-regs @gol +-mdisable-callt -mno-disable-callt @gol +-mv850e @gol -mv850 -mbig-switch} @emph{NS32K Options} -@gccoptlist{ --m32032 -m32332 -m32532 -m32081 -m32381 @gol +@gccoptlist{-m32032 -m32332 -m32532 -m32081 -m32381 @gol -mmult-add -mnomult-add -msoft-float -mrtd -mnortd @gol -mregparam -mnoregparam -msb -mnosb @gol -mbitfield -mnobitfield -mhimem -mnohimem} @emph{AVR Options} -@gccoptlist{ --mmcu=@var{mcu} -msize -minit-stack=@var{n} -mno-interrupts @gol +@gccoptlist{-mmcu=@var{mcu} -msize -minit-stack=@var{n} -mno-interrupts @gol -mcall-prologues -mno-tablejump -mtiny-stack} @emph{MCore Options} -@gccoptlist{ --mhardlit -mno-hardlit -mdiv -mno-div -mrelax-immediates @gol +@gccoptlist{-mhardlit -mno-hardlit -mdiv -mno-div -mrelax-immediates @gol -mno-relax-immediates -mwide-bitfields -mno-wide-bitfields @gol -m4byte-functions -mno-4byte-functions -mcallgraph-data @gol -mno-callgraph-data -mslow-bytes -mno-slow-bytes -mno-lsim @gol -mlittle-endian -mbig-endian -m210 -m340 -mstack-increment} @emph{MMIX Options} -@gccoptlist{ --mlibfuncs -mno-libfuncs -mepsilon -mno-epsilon -mabi=gnu @gol --mabi=mmixware -mzero-extend -mknuthdiv -mtoplevel-symbols @gol --melf -mbranch-predict -mno-branch-predict -mbase-addresses @gol --mno-base-addresses} +@gccoptlist{-mlibfuncs -mno-libfuncs -mepsilon -mno-epsilon -mabi=gnu @gol +-mabi=mmixware -mzero-extend -mknuthdiv -mtoplevel-symbols @gol +-melf -mbranch-predict -mno-branch-predict -mbase-addresses @gol +-mno-base-addresses -msingle-exit -mno-single-exit} @emph{IA-64 Options} -@gccoptlist{ --mbig-endian -mlittle-endian -mgnu-as -mgnu-ld -mno-pic @gol +@gccoptlist{-mbig-endian -mlittle-endian -mgnu-as -mgnu-ld -mno-pic @gol -mvolatile-asm-stop -mb-step -mregister-names -mno-sdata @gol --mconstant-gp -mauto-pic -minline-divide-min-latency @gol --minline-divide-max-throughput -mno-dwarf2-asm @gol +-mconstant-gp -mauto-pic -minline-float-divide-min-latency @gol +-minline-float-divide-max-throughput @gol +-minline-int-divide-min-latency @gol +-minline-int-divide-max-throughput -mno-dwarf2-asm @gol -mfixed-range=@var{register-range}} @emph{D30V Options} -@gccoptlist{ --mextmem -mextmemory -monchip -mno-asm-optimize @gol --masm-optimize -mbranch-cost=@var{n} -mcond-exec=@var{n}} +@gccoptlist{-mextmem -mextmemory -monchip -mno-asm-optimize @gol +-masm-optimize -mbranch-cost=@var{n} -mcond-exec=@var{n}} @emph{S/390 and zSeries Options} -@gccoptlist{ --mhard-float -msoft-float -mbackchain -mno-backchain @gol --msmall-exec -mno-small-exec -mmvcle -mno-mvcle @gol --m64 -m31 -mdebug -mno-debug} +@gccoptlist{-mhard-float -msoft-float -mbackchain -mno-backchain @gol +-msmall-exec -mno-small-exec -mmvcle -mno-mvcle @gol +-m64 -m31 -mdebug -mno-debug} @emph{CRIS Options} -@gccoptlist{ --mcpu=@var{cpu} -march=@var{cpu} -mtune=@var{cpu} @gol --mmax-stack-frame=@var{n} -melinux-stacksize=@var{n} @gol --metrax4 -metrax100 -mpdebug -mcc-init -mno-side-effects @gol --mstack-align -mdata-align -mconst-align @gol --m32-bit -m16-bit -m8-bit -mno-prologue-epilogue -mno-gotplt @gol --melf -maout -melinux -mlinux -sim -sim2} +@gccoptlist{-mcpu=@var{cpu} -march=@var{cpu} -mtune=@var{cpu} @gol +-mmax-stack-frame=@var{n} -melinux-stacksize=@var{n} @gol +-metrax4 -metrax100 -mpdebug -mcc-init -mno-side-effects @gol +-mstack-align -mdata-align -mconst-align @gol +-m32-bit -m16-bit -m8-bit -mno-prologue-epilogue -mno-gotplt @gol +-melf -maout -melinux -mlinux -sim -sim2} @emph{PDP-11 Options} -@gccoptlist{ --mfpu -msoft-float -mac0 -mno-ac0 -m40 -m45 -m10 @gol +@gccoptlist{-mfpu -msoft-float -mac0 -mno-ac0 -m40 -m45 -m10 @gol -mbcopy -mbcopy-builtin -mint32 -mno-int16 @gol -mint16 -mno-int32 -mfloat32 -mno-float64 @gol -mfloat64 -mno-float32 -mabshi -mno-abshi @gol @@ -644,44 +614,57 @@ in the following sections. -msplit -mno-split -munix-asm -mdec-asm} @emph{Xstormy16 Options} -@gccoptlist{ --msim} +@gccoptlist{-msim} @emph{Xtensa Options} -@gccoptlist{ --mbig-endian -mlittle-endian @gol --mdensity -mno-density @gol --mmac16 -mno-mac16 @gol --mmul16 -mno-mul16 @gol --mmul32 -mno-mul32 @gol --mnsa -mno-nsa @gol --mminmax -mno-minmax @gol --msext -mno-sext @gol --mbooleans -mno-booleans @gol --mhard-float -msoft-float @gol --mfused-madd -mno-fused-madd @gol --mserialize-volatile -mno-serialize-volatile @gol --mtext-section-literals -mno-text-section-literals @gol --mtarget-align -mno-target-align @gol --mlongcalls -mno-longcalls} +@gccoptlist{-mbig-endian -mlittle-endian @gol +-mdensity -mno-density @gol +-mmac16 -mno-mac16 @gol +-mmul16 -mno-mul16 @gol +-mmul32 -mno-mul32 @gol +-mnsa -mno-nsa @gol +-mminmax -mno-minmax @gol +-msext -mno-sext @gol +-mbooleans -mno-booleans @gol +-mhard-float -msoft-float @gol +-mfused-madd -mno-fused-madd @gol +-mserialize-volatile -mno-serialize-volatile @gol +-mtext-section-literals -mno-text-section-literals @gol +-mtarget-align -mno-target-align @gol +-mlongcalls -mno-longcalls} + +@emph{FRV Options} +@gccoptlist{-mgpr-32 -mgpr-64 -mfpr-32 -mfpr-64 @gol +-mhard-float -msoft-float -malloc-cc -mfixed-cc @gol +-mdword -mno-dword -mdouble -mno-double @gol +-mmedia -mno-media -mmuladd -mno-muladd -mlibrary-pic @gol +-macc-4 -macc-8 -mpack -mno-pack -mno-eflags @gol +-mcond-move -mno-cond-move -mscc -mno-scc @gol +-mcond-exec -mno-cond-exec -mvliw-branch -mno-vliw-branch @gol +-mmulti-cond-exec -mno-multi-cond-exec -mnested-cond-exec @gol +-mno-nested-cond-exec -mtomcat-stats @gol +-mcpu=@var{cpu}} + + @item Code Generation Options @xref{Code Gen Options,,Options for Code Generation Conventions}. -@gccoptlist{ --fcall-saved-@var{reg} -fcall-used-@var{reg} @gol --ffixed-@var{reg} -fexceptions @gol +@gccoptlist{-fcall-saved-@var{reg} -fcall-used-@var{reg} @gol +-ffixed-@var{reg} -fexceptions @gol -fnon-call-exceptions -funwind-tables @gol -fasynchronous-unwind-tables @gol -finhibit-size-directive -finstrument-functions @gol -fno-common -fno-ident -fno-gnu-linker @gol -fpcc-struct-return -fpic -fPIC @gol -freg-struct-return -fshared-data -fshort-enums @gol --fshort-double -fshort-wchar -fvolatile @gol +-fshort-double -fshort-wchar -fvolatile @gol -fvolatile-global -fvolatile-static @gol -fverbose-asm -fpack-struct -fstack-check @gol -fstack-limit-register=@var{reg} -fstack-limit-symbol=@var{sym} @gol -fargument-alias -fargument-noalias @gol --fargument-noalias-global -fleading-underscore} +-fargument-noalias-global -fleading-underscore @gol +-ftls-model=@var{model} @gol +-ftrapv -fbounds-check} @end table @menu @@ -818,6 +801,7 @@ assembler assembler-with-cpp ada f77 f77-cpp-input ratfor java +treelang @end example @item -x none @@ -974,11 +958,11 @@ from C, such as C++ and Objective-C) that the compiler accepts: @cindex ISO support @item -ansi @opindex ansi -In C mode, support all ISO C89 programs. In C++ mode, +In C mode, support all ISO C90 programs. In C++ mode, remove GNU extensions that conflict with ISO C++. This turns off certain features of GCC that are incompatible with ISO -C89 (when compiling C code), or of standard C++ (when compiling C++ code), +C90 (when compiling C code), or of standard C++ (when compiling C++ code), such as the @code{asm} and @code{typeof} keywords, and predefined macros such as @code{unix} and @code{vax} that identify the type of system you are using. It also enables the undesirable and @@ -1013,33 +997,39 @@ affected. @item -std= @opindex std Determine the language standard. This option is currently only -supported when compiling C@. A value for this option must be provided; -possible values are +supported when compiling C or C++. A value for this option must be +provided; possible values are @table @samp @item c89 @itemx iso9899:1990 -ISO C89 (same as @option{-ansi}). +ISO C90 (same as @option{-ansi}). @item iso9899:199409 -ISO C89 as modified in amendment 1. +ISO C90 as modified in amendment 1. @item c99 @itemx c9x @itemx iso9899:1999 @itemx iso9899:199x ISO C99. Note that this standard is not yet fully supported; see -@w{@uref{http://gcc.gnu.org/gcc-3.1/c99status.html}} for more information. The +@w{@uref{http://gcc.gnu.org/gcc-3.3/c99status.html}} for more information. The names @samp{c9x} and @samp{iso9899:199x} are deprecated. @item gnu89 -Default, ISO C89 plus GNU extensions (including some C99 features). +Default, ISO C90 plus GNU extensions (including some C99 features). @item gnu99 @item gnu9x ISO C99 plus GNU extensions. When ISO C99 is fully implemented in GCC, this will become the default. The name @samp{gnu9x} is deprecated. +@item c++98 +The 1998 ISO C++ standard plus amendments. + +@item gnu++98 +The same as @option{-std=c++98} plus GNU extensions. This is the +default for C++ code. @end table Even when this option is not specified, you can still use some of the @@ -1048,7 +1038,7 @@ previous C standards. For example, you may use @code{__restrict__} even when @option{-std=c99} is not specified. The @option{-std} options specifying some version of ISO C have the same -effects as @option{-ansi}, except that features that were not in ISO C89 +effects as @option{-ansi}, except that features that were not in ISO C90 but are in the specified version (for example, @samp{//} comments and the @code{inline} keyword in ISO C99) are not disabled. @@ -1086,7 +1076,7 @@ switch only affects the @code{asm} and @code{typeof} keywords, since @code{inline} is a standard keyword in ISO C99. @item -fno-builtin -@itemx -fno-builtin-@var{function} @r{(C and Objective-C only)} +@itemx -fno-builtin-@var{function} @opindex fno-builtin @cindex built-in functions Don't recognize built-in functions that do not begin with @@ -1104,15 +1094,8 @@ and faster, but since the function calls no longer appear as such, you cannot set a breakpoint on those calls, nor can you change the behavior of the functions by linking with a different library. -In C++, @option{-fno-builtin} is always in effect. The @option{-fbuiltin} -option has no effect. Therefore, in C++, the only way to get the -optimization benefits of built-in functions is to call the function -using the @samp{__builtin_} prefix. The GNU C++ Standard Library uses -built-in functions to implement many functions (like -@code{std::strchr}), so that you automatically get efficient code. - -With the @option{-fno-builtin-@var{function}} option, not available -when compiling C++, only the built-in function @var{function} is +With the @option{-fno-builtin-@var{function}} option +only the built-in function @var{function} is disabled. @var{function} must not begin with @samp{__builtin_}. If a function is named this is not built-in in this version of GCC, this option is ignored. There is no corresponding @@ -1148,6 +1131,10 @@ This is equivalent to @option{-fno-hosted}. @xref{Standards,,Language Standards Supported by GCC}, for details of freestanding and hosted environments. +@item -fms-extensions +@opindex fms-extensions +Accept some non-standard constructs used in Microsoft header files. + @item -trigraphs @opindex trigraphs Support ISO C trigraphs. The @option{-ansi} option (and @option{-std} @@ -1155,86 +1142,25 @@ options for strict ISO C conformance) implies @option{-trigraphs}. @item -no-integrated-cpp @opindex no-integrated-cpp -Invoke the external cpp during compilation. The default is to use the -integrated cpp (internal cpp). This option also allows a -user-supplied cpp via the @option{-B} option. This flag is applicable -in both C and C++ modes. +Performs a compilation in two passes: preprocessing and compiling. This +option allows a user supplied "cc1", "cc1plus", or "cc1obj" via the +@option{-B} option. The user supplied compilation step can then add in +an additional preprocessing step after normal preprocessing but before +compiling. The default is to use the integrated cpp (internal cpp) -We do not guarantee to retain this option in future, and we may change -its semantics. +The semantics of this option will change if "cc1", "cc1plus", and +"cc1obj" are merged. @cindex traditional C language @cindex C language, traditional @item -traditional -@opindex traditional -Attempt to support some aspects of traditional C compilers. -Specifically: - -@itemize @bullet -@item -All @code{extern} declarations take effect globally even if they -are written inside of a function definition. This includes implicit -declarations of functions. - -@item -The newer keywords @code{typeof}, @code{inline}, @code{signed}, @code{const} -and @code{volatile} are not recognized. (You can still use the -alternative keywords such as @code{__typeof__}, @code{__inline__}, and -so on.) - -@item -Comparisons between pointers and integers are always allowed. - -@item -Integer types @code{unsigned short} and @code{unsigned char} promote -to @code{unsigned int}. - -@item -Out-of-range floating point literals are not an error. - -@item -Certain constructs which ISO regards as a single invalid preprocessing -number, such as @samp{0xe-0xd}, are treated as expressions instead. - -@item -String ``constants'' are not necessarily constant; they are stored in -writable space, and identical looking constants are allocated -separately. (This is the same as the effect of -@option{-fwritable-strings}.) - -@cindex @code{longjmp} and automatic variables -@item -All automatic variables not declared @code{register} are preserved by -@code{longjmp}. Ordinarily, GNU C follows ISO C: automatic variables -not declared @code{volatile} may be clobbered. - -@item -@cindex @samp{\x} -@cindex @samp{\a} -@cindex escape sequences, traditional -The character escape sequences @samp{\x} and @samp{\a} evaluate as the -literal characters @samp{x} and @samp{a} respectively. Without -@w{@option{-traditional}}, @samp{\x} is a prefix for the hexadecimal -representation of a character, and @samp{\a} produces a bell. -@end itemize - -This option is deprecated and may be removed. - -You may wish to use @option{-fno-builtin} as well as @option{-traditional} -if your program uses names that are normally GNU C built-in functions for -other purposes of its own. - -You cannot use @option{-traditional} if you include any header files that -rely on ISO C features. Some vendors are starting to ship systems with -ISO C header files and you cannot use @option{-traditional} on such -systems to compile files that include any system headers. - -The @option{-traditional} option also enables @option{-traditional-cpp}. - -@item -traditional-cpp +@itemx -traditional-cpp @opindex traditional-cpp -Attempt to support some aspects of traditional C preprocessors. -See the GNU CPP manual for details. +@opindex traditional +Formerly, these options caused GCC to attempt to emulate a pre-standard +C compiler. They are now only supported with the @option{-E} switch. +The preprocessor continues to support a pre-standard mode. See the GNU +CPP manual for details. @item -fcond-mismatch @opindex fcond-mismatch @@ -1282,31 +1208,14 @@ declaration does not use either @code{signed} or @code{unsigned}. By default, such a bit-field is signed, because this is consistent: the basic integer types such as @code{int} are signed types. -However, when @option{-traditional} is used, bit-fields are all unsigned -no matter what. - @item -fwritable-strings @opindex fwritable-strings Store string constants in the writable data segment and don't uniquize them. This is for compatibility with old programs which assume they can -write into string constants. The option @option{-traditional} also has -this effect. +write into string constants. Writing into string constants is a very bad idea; ``constants'' should be constant. - -@item -fallow-single-precision -@opindex fallow-single-precision -Do not promote single precision math operations to double precision, -even when compiling with @option{-traditional}. - -Traditional K&R C promotes all floating point operations to double -precision, regardless of the sizes of the operands. On the -architecture for which you are compiling, single precision may be faster -than double precision. If you must use @option{-traditional}, but want -to use single precision operations when the operands are single -precision, use this option. This option has no effect when compiling -with ISO or GNU C conventions (the default). @end table @node C++ Dialect Options @@ -1332,6 +1241,17 @@ language supported by GCC@. Here is a list of options that are @emph{only} for compiling C++ programs: @table @gcctabopt + +@item -fabi-version=@var{n} +@opindex fabi-version +Use version @var{n} of the C++ ABI. Version 1 is the version of the C++ +ABI that first appeared in G++ 3.2. Version 0 will always be the +version that conforms most closely to the C++ ABI specification. +Therefore, the ABI obtained using version 0 will change as ABI bugs are +fixed. + +The default is version 1. + @item -fno-access-control @opindex fno-access-control Turn off all access checking. This switch is mainly useful for working @@ -1340,14 +1260,14 @@ around bugs in the access control code. @item -fcheck-new @opindex fcheck-new Check that the pointer returned by @code{operator new} is non-null -before attempting to modify the storage allocated. The current Working -Paper requires that @code{operator new} never return a null pointer, so -this check is normally unnecessary. - -An alternative to using this option is to specify that your -@code{operator new} does not throw any exceptions; if you declare it -@samp{throw()}, G++ will check the return value. See also @samp{new -(nothrow)}. +before attempting to modify the storage allocated. This check is +normally unnecessary because the C++ standard specifies that +@code{operator new} will only return @code{0} if it is declared +@samp{throw()}, in which case the compiler will always check the +return value even without this option. In all other cases, when +@code{operator new} has a non-empty exception specification, memory +exhaustion is signalled by throwing @code{std::bad_alloc}. See also +@samp{new (nothrow)}. @item -fconserve-space @opindex fconserve-space @@ -1478,10 +1398,9 @@ a name having multiple meanings within a class. @item -fpermissive @opindex fpermissive -Downgrade messages about nonconformant code from errors to warnings. By -default, G++ effectively sets @option{-pedantic-errors} without -@option{-pedantic}; this option reverses that. This behavior and this -option are superseded by @option{-pedantic}, which works as it does for GNU C@. +Downgrade some diagnostics about nonconformant code from errors to +warnings. Thus, using @option{-fpermissive} will allow some +nonconforming code to compile. @item -frepo @opindex frepo @@ -1568,7 +1487,7 @@ You should rewrite your code to avoid these warnings if you are concerned about the fact that code generated by G++ may not be binary compatible with code generated by other compilers. -The known incompatibilites at this point include: +The known incompatibilities at this point include: @itemize @bullet @@ -1605,18 +1524,66 @@ explicitly padding @code{A} so that its size is a multiple of its alignment (ignoring virtual base classes); that will cause G++ and other compilers to layout @code{C} identically. +@item +Incorrect handling of bit-fields with declared widths greater than that +of their underlying types, when the bit-fields appear in a union. For +example: + +@smallexample +union U @{ int i : 4096; @}; +@end smallexample + +@noindent +Assuming that an @code{int} does not have 4096 bits, G++ will make the +union too small by the number of bits in an @code{int}. + +@item +Empty classes can be placed at incorrect offsets. For example: + +@smallexample +struct A @{@}; + +struct B @{ + A a; + virtual void f (); +@}; + +struct C : public B, public A @{@}; +@end smallexample + +@noindent +G++ will place the @code{A} base class of @code{C} at a nonzero offset; +it should be placed at offset zero. G++ mistakenly believes that the +@code{A} data member of @code{B} is already at offset zero. + +@item +Names of template functions whose types involve @code{typename} or +template template parameters can be mangled incorrectly. + +@smallexample +template <typename Q> +void f(typename Q::X) @{@} + +template <template <typename> class Q> +void f(typename Q<int>::X) @{@} +@end smallexample + +@noindent +Instantiations of these templates may be mangled incorrectly. + @end itemize @item -Wctor-dtor-privacy @r{(C++ only)} @opindex Wctor-dtor-privacy Warn when a class seems unusable, because all the constructors or destructors in a class are private and the class has no friends or -public static member functions. +public static member functions. This warning is enabled by default. @item -Wnon-virtual-dtor @r{(C++ only)} @opindex Wnon-virtual-dtor Warn when a class declares a non-virtual destructor that should probably be virtual, because it looks like the class will be used polymorphically. +This warning is enabled by @option{-Wall}. @item -Wreorder @r{(C++ only)} @opindex Wreorder @@ -1635,7 +1602,7 @@ struct A @{ Here the compiler will warn that the member initializers for @samp{i} and @samp{j} will be rearranged to match the declaration order of the -members. +members. This warning is enabled by @option{-Wall}. @end table The following @option{-W@dots{}} options are not affected by @option{-Wall}. @@ -1810,7 +1777,9 @@ runtime. This is the default for most types of systems. @item -fnext-runtime @opindex fnext-runtime Generate output compatible with the NeXT runtime. This is the default -for NeXT-based systems, including Darwin and Mac OS X@. +for NeXT-based systems, including Darwin and Mac OS X@. The macro +@code{__NEXT_RUNTIME__} is predefined if (and only if) this option is +used. @item -gen-decls @opindex gen-decls @@ -1819,12 +1788,39 @@ file named @file{@var{sourcename}.decl}. @item -Wno-protocol @opindex Wno-protocol -Do not warn if methods required by a protocol are not implemented -in the class adopting it. +If a class is declared to implement a protocol, a warning is issued for +every method in the protocol that is not implemented by the class. The +default behavior is to issue a warning for every method not explicitly +implemented in the class, even if a method implementation is inherited +from the superclass. If you use the @code{-Wno-protocol} option, then +methods inherited from the superclass are considered to be implemented, +and no warning is issued for them. @item -Wselector @opindex Wselector -Warn if a selector has multiple methods of different types defined. +Warn if multiple methods of different types for the same selector are +found during compilation. The check is performed on the list of methods +in the final stage of compilation. Additionally, a check is performed +that for each selector appearing in a @code{@@selector(@dots{})} +expression, a corresponding method with that selector has been found +during compilation. Because these checks scan the method table only at +the end of compilation, these warnings are not produced if the final +stage of compilation is not reached, for example because an error is +found during compilation, or because the @code{-fsyntax-only} option is +being used. + +@item -Wundeclared-selector +@opindex Wundeclared-selector +Warn if a @code{@@selector(@dots{})} expression referring to an +undeclared selector is found. A selector is considered undeclared if no +method with that name has been declared (explicitly, in an +@code{@@interface} or @code{@@protocol} declaration, or implicitly, in +an @code{@@implementation} section) before the +@code{@@selector(@dots{})} expression. This option always performs its +checks as soon as a @code{@@selector(@dots{})} expression is found +(while @code{-Wselector} only performs its checks in the final stage of +compilation), and so additionally enforces the coding style convention +that methods and selectors must be declared before being used. @c not documented because only avail via -Wp @c @item -print-objc-runtime-info @@ -1975,7 +1971,7 @@ attributes (@pxref{Function Attributes}), in the @code{printf}, not in the C standard) families. The formats are checked against the format features supported by GNU -libc version 2.2. These include all ISO C89 and C99 features, as well +libc version 2.2. These include all ISO C90 and C99 features, as well as features from the Single Unix Specification and some BSD and GNU extensions. Other library implementations may not support all these features; GCC does not support warning about features that go beyond a @@ -1985,11 +1981,14 @@ in the selected standard version (but not for @code{strfmon} formats, since those are not in any version of the C standard). @xref{C Dialect Options,,Options Controlling C Dialect}. +Since @option{-Wformat} also checks for null format arguments for +several functions, @option{-Wformat} also implies @option{-Wnonnull}. + @option{-Wformat} is included in @option{-Wall}. For more control over some aspects of format checking, the options @option{-Wno-format-y2k}, -@option{-Wno-format-extra-args}, @option{-Wformat-nonliteral}, -@option{-Wformat-security} and @option{-Wformat=2} are available, but are -not included in @option{-Wall}. +@option{-Wno-format-extra-args}, @option{-Wno-format-zero-length}, +@option{-Wformat-nonliteral}, @option{-Wformat-security}, and +@option{-Wformat=2} are available, but are not included in @option{-Wall}. @item -Wno-format-y2k @opindex Wno-format-y2k @@ -2010,6 +2009,11 @@ in the case of @code{scanf} formats, this option will suppress the warning if the unused arguments are all pointers, since the Single Unix Specification says that such unused arguments are allowed. +@item -Wno-format-zero-length +@opindex Wno-format-zero-length +If @option{-Wformat} is specified, do not warn about zero-length formats. +The C standard specifies that zero-length formats are allowed. + @item -Wformat-nonliteral @opindex Wformat-nonliteral If @option{-Wformat} is specified, also warn if the format string is not a @@ -2034,6 +2038,14 @@ Enable @option{-Wformat} plus format checks not included in @option{-Wformat}. Currently equivalent to @samp{-Wformat -Wformat-nonliteral -Wformat-security}. +@item -Wnonnull +@opindex Wnonnull +Enable warning about passing a null pointer for arguments marked as +requiring a non-null value by the @code{nonnull} function attribute. + +@option{-Wnonnull} is included in @option{-Wall} and @option{-Wformat}. It +can be disabled with the @option{-Wno-nonnull} option. + @item -Wimplicit-int @opindex Wimplicit-int Warn when a declaration does not specify a type. @@ -2176,6 +2188,18 @@ enumeration. (The presence of a @code{default} label prevents this warning.) @code{case} labels outside the enumeration range also provoke warnings when this option is used. +@item -Wswitch-default +@opindex Wswitch-switch +Warn whenever a @code{switch} statement does not have a @code{default} +case. + +@item -Wswitch-enum +@opindex Wswitch-enum +Warn whenever a @code{switch} statement has an index of enumeral type +and lacks a @code{case} for one or more of the named codes of that +enumeration. @code{case} labels outside the enumeration range also +provoke warnings when this option is used. + @item -Wtrigraphs @opindex Wtrigraphs Warn if any trigraphs are encountered that might change the meaning of @@ -2216,7 +2240,7 @@ To suppress this warning cast the expression to @samp{void}. @item -Wunused @opindex Wunused -All all the above @option{-Wunused} options combined. +All the above @option{-Wunused} options combined. In order to get a warning about an unused function parameter, you must either specify @samp{-W -Wunused} or separately specify @@ -2297,13 +2321,6 @@ Some spurious warnings can be avoided if you declare all the functions you use that never return as @code{noreturn}. @xref{Function Attributes}. -@item -Wreorder @r{(C++ only)} -@opindex Wreorder -@cindex reordering, warning -@cindex warning for reordering of member initializers -Warn when the order of member initializers given in the code does not -match the order in which they must be executed. For instance: - @item -Wunknown-pragmas @opindex Wunknown-pragmas @cindex warning for unknown pragmas @@ -2314,41 +2331,22 @@ GCC@. If this command line option is used, warnings will even be issued for unknown pragmas in system header files. This is not the case if the warnings were only enabled by the @option{-Wall} command line option. +@item -Wstrict-aliasing +@opindex Wstrict-aliasing +This option is only active when @option{-fstrict-aliasing} is active. +It warns about code which might break the strict aliasing rules that the +compiler is using for optimization. The warning does not catch all +cases, but does attempt to catch the more common pitfalls. It is +included in @option{-Wall}. + @item -Wall @opindex Wall All of the above @samp{-W} options combined. This enables all the warnings about constructions that some users consider questionable, and that are easy to avoid (or modify to prevent the warning), even in -conjunction with macros. - -@item -Wdiv-by-zero -@opindex Wno-div-by-zero -@opindex Wdiv-by-zero -Warn about compile-time integer division by zero. This is default. To -inhibit the warning messages, use @option{-Wno-div-by-zero}. Floating -point division by zero is not warned about, as it can be a legitimate -way of obtaining infinities and NaNs. - -@item -Wmultichar -@opindex Wno-multichar -@opindex Wmultichar -Warn if a multicharacter constant (@samp{'FOOF'}) is used. This is -default. To inhibit the warning messages, use @option{-Wno-multichar}. -Usually they indicate a typo in the user's code, as they have -implementation-defined values, and should not be used in portable code. - -@item -Wsystem-headers -@opindex Wsystem-headers -@cindex warnings from system headers -@cindex system headers, warnings from -Print warning messages for constructs found in system header files. -Warnings from system headers are normally suppressed, on the assumption -that they usually do not indicate real problems and would only make the -compiler output harder to read. Using this command line option tells -GCC to emit warnings from system headers as if they occurred in user -code. However, note that using @option{-Wall} in conjunction with this -option will @emph{not} warn about unknown pragmas in system -headers---for that, @option{-Wunknown-pragmas} must also be used. +conjunction with macros. This also enables some language-specific +warnings described in @ref{C++ Dialect Options} and +@ref{Objective-C Dialect Options}. @end table The following @option{-W@dots{}} options are not implied by @option{-Wall}. @@ -2437,6 +2435,26 @@ struct s x = @{ 3, 4 @}; @end smallexample @end itemize +@item -Wno-div-by-zero +@opindex Wno-div-by-zero +@opindex Wdiv-by-zero +Do not warn about compile-time integer division by zero. Floating point +division by zero is not warned about, as it can be a legitimate way of +obtaining infinities and NaNs. + +@item -Wsystem-headers +@opindex Wsystem-headers +@cindex warnings from system headers +@cindex system headers, warnings from +Print warning messages for constructs found in system header files. +Warnings from system headers are normally suppressed, on the assumption +that they usually do not indicate real problems and would only make the +compiler output harder to read. Using this command line option tells +GCC to emit warnings from system headers as if they occurred in user +code. However, note that using @option{-Wall} in conjunction with this +option will @emph{not} warn about unknown pragmas in system +headers---for that, @option{-Wunknown-pragmas} must also be used. + @item -Wfloat-equal @opindex Wfloat-equal Warn if floating point values are used in equality comparisons. @@ -2444,7 +2462,7 @@ Warn if floating point values are used in equality comparisons. The idea behind this is that sometimes it is convenient (for the programmer) to consider floating-point values as approximations to infinitely precise real numbers. If you are doing this, then you need -to compute (by analysing the code, or in some other way) the maximum or +to compute (by analyzing the code, or in some other way) the maximum or likely maximum error that the computation introduces, and allow for it when performing comparisons (and when producing output, but that's a different problem). In particular, instead of testing for equality, you @@ -2529,12 +2547,25 @@ Conversions by prototypes between fixed/floating point values and vice versa. The absence of these prototypes when compiling with traditional C would cause serious problems. This is a subset of the possible conversion warnings, for the full set use @option{-Wconversion}. + +@item +Use of ISO C style function definitions. This warning intentionally is +@emph{not} issued for prototype declarations or variadic functions +because these ISO C features will appear in your code when using +libiberty's traditional C compatibility macros, @code{PARAMS} and +@code{VPARAMS}. This warning is also bypassed for nested functions +because that feature is already a gcc extension and thus not relevant to +traditional C compatibility. @end itemize @item -Wundef @opindex Wundef Warn if an undefined identifier is evaluated in an @samp{#if} directive. +@item -Wendif-labels +@opindex Wendif-labels +Warn whenever an @samp{#else} or an @samp{#endif} are followed by text. + @item -Wshadow @opindex Wshadow Warn whenever a local variable shadows another local variable, parameter or @@ -2602,8 +2633,8 @@ casts like @code{(unsigned) -1}. @cindex signed and unsigned values, comparison warning Warn when a comparison between signed and unsigned values could produce an incorrect result when the signed value is converted to unsigned. -This warning is also enabled by @option{-W}; to get the other warnings -of @option{-W} without this warning, use @samp{-W -Wno-sign-compare}. +This warning is enabled by @option{-W}, and by @option{-Wall} +in C++ only. @item -Waggregate-return @opindex Waggregate-return @@ -2625,7 +2656,7 @@ declaration. This warning is issued even if the definition itself provides a prototype. The aim is to detect global functions that fail to be declared in header files. -@item -Wmissing-declarations +@item -Wmissing-declarations @r{(C only)} @opindex Wmissing-declarations Warn if a global function is defined without a previous declaration. Do so even if the definition itself provides a prototype. @@ -2653,6 +2684,13 @@ case, and some functions for which @code{format} attributes are appropriate may not be detected. This option has no effect unless @option{-Wformat} is enabled (possibly by @option{-Wall}). +@item -Wno-multichar +@opindex Wno-multichar +@opindex Wmultichar +Do not warn if a multicharacter constant (@samp{'FOOF'}) is used. +Usually they indicate a typo in the user's code, as they have +implementation-defined values, and should not be used in portable code. + @item -Wno-deprecated-declarations @opindex Wno-deprecated-declarations Do not warn about uses of functions, variables, and types marked as @@ -2723,6 +2761,15 @@ code is to provide behavior which is selectable at compile-time. @item -Winline @opindex Winline Warn if a function can not be inlined and it was declared as inline. +Even with this option, the compiler will not warn about failures to +inline functions declared in system headers. + +The compiler uses a variety of heuristics to determine whether or not +to inline a function. For example, the compiler takes into account +the size of the function being inlined and the the amount of inlining +that has already been done in the current function. Therefore, +seemingly insignificant changes in the source program can cause the +warnings produced by @option{-Winline} to appear or disappear. @item -Wlong-long @opindex Wlong-long @@ -2831,6 +2878,8 @@ Produce debugging information in DWARF version 1 format (if that is supported). This is the format used by SDB on most System V Release 4 systems. +This option is deprecated. + @item -gdwarf+ @opindex gdwarf+ Produce debugging information in DWARF version 1 format (if that is @@ -2838,6 +2887,8 @@ supported), using GNU extensions understood only by the GNU debugger (GDB)@. The use of these extensions is likely to make other debuggers crash or refuse to read the program. +This option is deprecated. + @item -gdwarf-2 @opindex gdwarf-2 Produce debugging information in DWARF version 2 format (if that is @@ -2871,19 +2922,25 @@ and DWARF2, neither @option{-gdwarf} nor @option{-gdwarf-2} accept a concatenated debug level. Instead use an additional @option{-g@var{level}} option to change the debug level for DWARF1 or DWARF2. -@cindex @code{prof} +@item -feliminate-dwarf2-dups +@opindex feliminate-dwarf2-dups +Compress DWARF2 debugging information by eliminating duplicated +information about each symbol. This option only makes sense when +generating DWARF2 debugging information with @option{-gdwarf-2}. + +@cindex @command{prof} @item -p @opindex p Generate extra code to write profile information suitable for the -analysis program @code{prof}. You must use this option when compiling +analysis program @command{prof}. You must use this option when compiling the source files you want data about, and you must also use it when linking. -@cindex @code{gprof} +@cindex @command{gprof} @item -pg @opindex pg Generate extra code to write profile information suitable for the -analysis program @code{gprof}. You must use this option when compiling +analysis program @command{gprof}. You must use this option when compiling the source files you want data about, and you must also use it when linking. @@ -2904,11 +2961,16 @@ allocation when it finishes. @item -fprofile-arcs @opindex fprofile-arcs -Instrument @dfn{arcs} during compilation to generate coverage data -or for profile-directed block ordering. During execution the program +Instrument @dfn{arcs} during compilation to generate coverage data or +for profile-directed block ordering. During execution the program records how many times each branch is executed and how many times it is taken. When the compiled program exits it saves this data to a file -called @file{@var{sourcename}.da} for each source file. +called @file{@var{auxname}.da} for each source file. @var{auxname} is +generated from the name of the output file, if explicitly specified and +it is not the final executable, otherwise it is the basename of the +source file. In both cases any suffix is removed (e.g. @file{foo.da} +for input file @file{dir/foo.c}, or @file{dir/foo.da} for output file +specified as @option{-o dir/foo.o}). For profile-directed block ordering, compile the program with @option{-fprofile-arcs} plus optimization and code generation options, @@ -2918,7 +2980,7 @@ optimization and code generation options plus @option{-fbranch-probabilities} (@pxref{Optimize Options,,Options that Control Optimization}). -The other use of @option{-fprofile-arcs} is for use with @code{gcov}, +The other use of @option{-fprofile-arcs} is for use with @command{gcov}, when it is used with the @option{-ftest-coverage} option. With @option{-fprofile-arcs}, for each function of your program GCC @@ -2933,19 +2995,19 @@ block must be created to hold the instrumentation code. @item -ftest-coverage @opindex ftest-coverage Create data files for the @command{gcov} code-coverage utility -(@pxref{Gcov,, @command{gcov}---a Test Coverage Program}). -The data file names begin with the name of your source file: +(@pxref{Gcov,, @command{gcov}---a Test Coverage Program}). See +@option{-fprofile-arcs} option above for a description of @var{auxname}. @table @gcctabopt -@item @var{sourcename}.bb -A mapping from basic blocks to line numbers, which @code{gcov} uses to +@item @var{auxname}.bb +A mapping from basic blocks to line numbers, which @command{gcov} uses to associate basic block execution counts with line numbers. -@item @var{sourcename}.bbg -A list of all arcs in the program flow graph. This allows @code{gcov} +@item @var{auxname}.bbg +A list of all arcs in the program flow graph. This allows @command{gcov} to reconstruct the program flow graph, so that it can compute all basic block and arc execution counts from the information in the -@code{@var{sourcename}.da} file. +@file{@var{auxname}.da} file. @end table Use @option{-ftest-coverage} with @option{-fprofile-arcs}; the latter @@ -2953,9 +3015,9 @@ option adds instrumentation to the program, which then writes execution counts to another data file: @table @gcctabopt -@item @var{sourcename}.da +@item @var{auxname}.da Runtime arc execution counts, used in conjunction with the arc -information in the file @code{@var{sourcename}.bbg}. +information in the file @file{@var{auxname}.bbg}. @end table Coverage data will map better to the source files if @@ -2966,8 +3028,12 @@ Coverage data will map better to the source files if Says to make debugging dumps during compilation at times specified by @var{letters}. This is used for debugging the compiler. The file names for most of the dumps are made by appending a pass number and a word to -the source file name (e.g. @file{foo.c.00.rtl} or @file{foo.c.01.sibling}). -Here are the possible letters for use in @var{letters}, and their meanings: +the @var{dumpname}. @var{dumpname} is generated from the name of the +output file, if explicitly specified and it is not an executable, +otherwise it is the basename of the source file. In both cases any +suffix is removed (e.g. @file{foo.00.rtl} or @file{foo.01.sibling}). +Here are the possible letters for use in @var{letters}, and their +meanings: @table @samp @item A @@ -2978,16 +3044,16 @@ Annotate the assembler output with miscellaneous debugging information. Dump after computing branch probabilities, to @file{@var{file}.14.bp}. @item B @opindex dB -Dump after block reordering, to @file{@var{file}.29.bbro}. +Dump after block reordering, to @file{@var{file}.32.bbro}. @item c @opindex dc -Dump after instruction combination, to the file @file{@var{file}.16.combine}. +Dump after instruction combination, to the file @file{@var{file}.19.combine}. @item C @opindex dC -Dump after the first if conversion, to the file @file{@var{file}.17.ce}. +Dump after the first if conversion, to the file @file{@var{file}.15.ce1}. @item d @opindex dd -Dump after delayed branch scheduling, to @file{@var{file}.31.dbr}. +Dump after delayed branch scheduling, to @file{@var{file}.34.dbr}. @item D @opindex dD Dump all macro definitions, at the end of preprocessing, in addition to @@ -2998,28 +3064,23 @@ Dump after SSA optimizations, to @file{@var{file}.04.ssa} and @file{@var{file}.07.ussa}. @item E @opindex dE -Dump after the second if conversion, to @file{@var{file}.26.ce2}. +Dump after the second if conversion, to @file{@var{file}.29.ce3}. @item f @opindex df -Dump after life analysis, to @file{@var{file}.15.life}. +Dump after control and data flow analysis, to @file{@var{file}.14.cfg}. +Also dump after life analysis, to @file{@var{file}.18.life}. @item F @opindex dF -Dump after purging @code{ADDRESSOF} codes, to @file{@var{file}.09.addressof}. +Dump after purging @code{ADDRESSOF} codes, to @file{@var{file}.10.addressof}. @item g @opindex dg -Dump after global register allocation, to @file{@var{file}.21.greg}. +Dump after global register allocation, to @file{@var{file}.24.greg}. +@item G +@opindex dG +Dump after GCSE, to @file{@var{file}.11.gcse}. @item h @opindex dh Dump after finalization of EH handling code, to @file{@var{file}.02.eh}. -@item k -@opindex dk -Dump after reg-to-stack conversion, to @file{@var{file}.28.stack}. -@item o -@opindex do -Dump after post-reload optimizations, to @file{@var{file}.22.postreload}. -@item G -@opindex dG -Dump after GCSE, to @file{@var{file}.10.gcse}. @item i @opindex di Dump after sibling call optimizations, to @file{@var{file}.01.sibling}. @@ -3028,49 +3089,62 @@ Dump after sibling call optimizations, to @file{@var{file}.01.sibling}. Dump after the first jump optimization, to @file{@var{file}.03.jump}. @item k @opindex dk -Dump after conversion from registers to stack, to @file{@var{file}.32.stack}. +Dump after conversion from registers to stack, to @file{@var{file}.31.stack}. @item l @opindex dl -Dump after local register allocation, to @file{@var{file}.20.lreg}. +Dump after local register allocation, to @file{@var{file}.23.lreg}. @item L @opindex dL -Dump after loop optimization, to @file{@var{file}.11.loop}. +Dump after loop optimization, to @file{@var{file}.12.loop}. @item M @opindex dM -Dump after performing the machine dependent reorganisation pass, to -@file{@var{file}.30.mach}. +Dump after performing the machine dependent reorganization pass, to +@file{@var{file}.33.mach}. @item n @opindex dn -Dump after register renumbering, to @file{@var{file}.25.rnreg}. +Dump after register renumbering, to @file{@var{file}.28.rnreg}. @item N @opindex dN -Dump after the register move pass, to @file{@var{file}.18.regmove}. +Dump after the register move pass, to @file{@var{file}.21.regmove}. +@item o +@opindex do +Dump after post-reload optimizations, to @file{@var{file}.25.postreload}. @item r @opindex dr Dump after RTL generation, to @file{@var{file}.00.rtl}. @item R @opindex dR -Dump after the second scheduling pass, to @file{@var{file}.27.sched2}. +Dump after the second scheduling pass, to @file{@var{file}.30.sched2}. @item s @opindex ds Dump after CSE (including the jump optimization that sometimes follows -CSE), to @file{@var{file}.08.cse}. +CSE), to @file{@var{file}.09.cse}. @item S @opindex dS -Dump after the first scheduling pass, to @file{@var{file}.19.sched}. +Dump after the first scheduling pass, to @file{@var{file}.22.sched}. @item t @opindex dt Dump after the second CSE pass (including the jump optimization that -sometimes follows CSE), to @file{@var{file}.12.cse2}. +sometimes follows CSE), to @file{@var{file}.17.cse2}. +@item T +@opindex dT +Dump after running tracer, to @file{@var{file}.16.tracer}. +@item u +@opindex du +Dump after null pointer elimination pass to @file{@var{file}.08.null}. @item w @opindex dw -Dump after the second flow pass, to @file{@var{file}.23.flow2}. +Dump after the second flow pass, to @file{@var{file}.26.flow2}. +@item W +@opindex dW +Dump after SSA conditional constant propagation, to +@file{@var{file}.05.ssaccp}. @item X @opindex dX Dump after SSA dead code elimination, to @file{@var{file}.06.ssadce}. @item z @opindex dz -Dump after the peephole pass, to @file{@var{file}.24.peephole2}. +Dump after the peephole pass, to @file{@var{file}.27.peephole2}. @item a @opindex da Produce all the dumps listed above. @@ -3160,6 +3234,14 @@ Dump after all tree based optimization, to @file{@var{file}.optimized}. Dump after function inlining, to @file{@var{file}.inlined}. @end table +@item -frandom-seed=@var{string} +@opindex frandom-string +This option provides a seed that GCC uses when it would otherwise use +random numbers. At present, this is used to generate certain symbol names +that have to be different in every compiled file. + +The @var{string} should be different for every file you compile. + @item -fsched-verbose=@var{n} @opindex fsched-verbose On targets that use instruction scheduling, this option controls the @@ -3177,14 +3259,6 @@ and unit/insn info. For @var{n} greater than two, it includes RTL at abort point, control-flow and regions info. And for @var{n} over four, @option{-fsched-verbose} also includes dependence info. -@item -fpretend-float -@opindex fpretend-float -When running a cross-compiler, pretend that the target machine uses the -same floating point format as the host machine. This causes incorrect -output of the actual floating constants, but the actual instruction -sequence will probably be the same as GCC would make when running on -the target machine. - @item -save-temps @opindex save-temps Store the usual ``temporary'' intermediate files permanently; place them @@ -3280,7 +3354,22 @@ is used when GCC itself is being built.) @xref{Spec Files}. @cindex optimize options @cindex options, optimization -These options control various sorts of optimizations: +These options control various sorts of optimizations. + +Without any optimization option, the compiler's goal is to reduce the +cost of compilation and to make debugging produce the expected +results. Statements are independent: if you stop the program with a +breakpoint between statements, you can then assign a new value to any +variable or change the program counter to any other statement in the +function and get exactly the results you would expect from the source +code. + +Turning on optimization flags makes the compiler attempt to improve +the performance and/or code size at the expense of compilation time +and possibly the ability to debug the program. + +Not all optimizations are controlled directly by a flag. Only +optimizations that have a flag are listed. @table @gcctabopt @item -O @@ -3290,17 +3379,25 @@ These options control various sorts of optimizations: Optimize. Optimizing compilation takes somewhat more time, and a lot more memory for a large function. -Without @option{-O}, the compiler's goal is to reduce the cost of -compilation and to make debugging produce the expected results. -Statements are independent: if you stop the program with a breakpoint -between statements, you can then assign a new value to any variable or -change the program counter to any other statement in the function and -get exactly the results you would expect from the source code. - With @option{-O}, the compiler tries to reduce code size and execution time, without performing any optimizations that take a great deal of compilation time. +@option{-O} turns on the following optimization flags: +@gccoptlist{-fdefer-pop @gol +-fmerge-constants @gol +-fthread-jumps @gol +-floop-optimize @gol +-fcrossjumping @gol +-fif-conversion @gol +-fif-conversion2 @gol +-fdelayed-branch @gol +-fguess-branch-probability @gol +-fcprop-registers} + +@option{-O} also turns on @option{-fomit-frame-pointer} on machines +where doing so does not interfere with debugging. + @item -O2 @opindex O2 Optimize even more. GCC performs nearly all supported optimizations @@ -3309,10 +3406,25 @@ perform loop unrolling or function inlining when you specify @option{-O2}. As compared to @option{-O}, this option increases both compilation time and the performance of the generated code. -@option{-O2} turns on all optional optimizations except for loop unrolling, -function inlining, and register renaming. It also turns on the -@option{-fforce-mem} option on all machines and frame pointer elimination -on machines where doing so does not interfere with debugging. +@option{-O2} turns on all optimization flags specified by @option{-O}. It +also turns on the following optimization flags: +@gccoptlist{-fforce-mem @gol +-foptimize-sibling-calls @gol +-fstrength-reduce @gol +-fcse-follow-jumps -fcse-skip-blocks @gol +-frerun-cse-after-loop -frerun-loop-opt @gol +-fgcse -fgcse-lm -fgcse-sm @gol +-fdelete-null-pointer-checks @gol +-fexpensive-optimizations @gol +-fregmove @gol +-fschedule-insns -fschedule-insns2 @gol +-fsched-interblock -fsched-spec @gol +-fcaller-saves @gol +-fpeephole2 @gol +-freorder-blocks -freorder-functions @gol +-fstrict-aliasing @gol +-falign-functions -falign-jumps @gol +-falign-loops -falign-labels} Please note the warning under @option{-fgcse} about invoking @option{-O2} on programs that use computed gotos. @@ -3325,7 +3437,7 @@ Optimize yet more. @option{-O3} turns on all optimizations specified by @item -O0 @opindex O0 -Do not optimize. +Do not optimize. This is the default. @item -Os @opindex Os @@ -3333,33 +3445,27 @@ Optimize for size. @option{-Os} enables all @option{-O2} optimizations that do not typically increase code size. It also performs further optimizations designed to reduce code size. +@option{-Os} disables the following optimization flags: +@gccoptlist{-falign-functions -falign-jumps -falign-loops @gol +-falign-labels -freorder-blocks -fprefetch-loop-arrays} + If you use multiple @option{-O} options, with or without level numbers, the last such option is the one that is effective. @end table Options of the form @option{-f@var{flag}} specify machine-independent flags. Most flags have both positive and negative forms; the negative -form of @option{-ffoo} would be @option{-fno-foo}. In the table below, -only one of the forms is listed---the one which is not the default. -You can figure out the other form by either removing @samp{no-} or -adding it. - -@table @gcctabopt -@item -ffloat-store -@opindex ffloat-store -Do not store floating point variables in registers, and inhibit other -options that might change whether a floating point value is taken from a -register or memory. +form of @option{-ffoo} would be @option{-fno-foo}. In the table +below, only one of the forms is listed---the one you typically will +use. You can figure out the other form by either removing @samp{no-} +or adding it. -@cindex floating point precision -This option prevents undesirable excess precision on machines such as -the 68000 where the floating registers (of the 68881) keep more -precision than a @code{double} is supposed to have. Similarly for the -x86 architecture. For most programs, the excess precision does only -good, but a few programs rely on the precise definition of IEEE floating -point. Use @option{-ffloat-store} for such programs, after modifying -them to store all pertinent intermediate computations into variables. +The following options control specific optimizations. They are either +activated by @option{-O} options or are related to ones that are. You +can use the following flags in the rare cases when ``fine-tuning'' of +optimizations to be performed is desired. +@table @gcctabopt @item -fno-default-inline @opindex fno-default-inline Do not make member functions inline by default merely because they are @@ -3375,13 +3481,17 @@ returns. For machines which must pop arguments after a function call, the compiler normally lets arguments accumulate on the stack for several function calls and pops them all at once. +Disabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}. + @item -fforce-mem @opindex fforce-mem Force memory operands to be copied into registers before doing arithmetic on them. This produces better code by making all memory references potential common subexpressions. When they are not common subexpressions, instruction combination should eliminate the separate -register-load. The @option{-O2} option turns on this option. +register-load. + +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}. @item -fforce-addr @opindex fforce-addr @@ -3404,14 +3514,13 @@ machine-description macro @code{FRAME_POINTER_REQUIRED} controls whether a target machine supports this flag. @xref{Registers,,Register Usage, gccint, GNU Compiler Collection (GCC) Internals}. +Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}. + @item -foptimize-sibling-calls @opindex foptimize-sibling-calls Optimize sibling and tail recursive calls. -@item -ftrapv -@opindex ftrapv -This option generates traps for signed overflow on addition, subtraction, -multiplication operations. +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}. @item -fno-inline @opindex fno-inline @@ -3429,11 +3538,13 @@ If all calls to a given function are integrated, and the function is declared @code{static}, then the function is normally not output as assembler code in its own right. +Enabled at level @option{-O3}. + @item -finline-limit=@var{n} @opindex finline-limit By default, gcc limits the size of functions that can be inlined. This flag allows the control of this limit for functions that are explicitly marked as -inline (ie marked with the inline keyword or defined within the class +inline (i.e., marked with the inline keyword or defined within the class definition in c++). @var{n} is the size of functions that can be inlined in number of pseudo instructions (not counting parameter handling). The default value of @var{n} is 600. @@ -3443,6 +3554,28 @@ the compilation faster and less code will be inlined (which presumably means slower programs). This option is particularly useful for programs that use inlining heavily such as those based on recursive templates with C++. +Inlining is actually controlled by a number of parameters, which may be +specified individually by using @option{--param @var{name}=@var{value}}. +The @option{-finline-limit=@var{n}} option sets some of these parameters +as follows: + + @table @gcctabopt + @item max-inline-insns + is set to @var{n}. + @item max-inline-insns-single + is set to @var{n}/2. + @item max-inline-insns-auto + is set to @var{n}/2. + @item min-inline-insns + is set to 130 or @var{n}/4, whichever is smaller. + @item max-inline-insns-rtl + is set to @var{n}. + @end table + +Using @option{-finline-limit=600} thus results in the default settings +for these parameters. See below for a documentation of the individual +parameters controlling inlining. + @emph{Note:} pseudo instruction represents, in this particular context, an abstract measurement of function's size. In no way, it represents a count of assembly instructions and as such its exact meaning might change from one @@ -3466,10 +3599,13 @@ optimization is turned on, use the @option{-fno-keep-static-consts} option. @item -fmerge-constants Attempt to merge identical constants (string constants and floating point -constants) accross compilation units. +constants) across compilation units. -This option is default for optimized compilation if assembler and linker -support it. Use @option{-fno-merge-constants} to inhibit this behavior. +This option is the default for optimized compilation if the assembler and +linker support it. Use @option{-fno-merge-constants} to inhibit this +behavior. + +Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}. @item -fmerge-all-constants Attempt to merge identical constants and identical variables. @@ -3489,6 +3625,9 @@ register, compare it against zero, then branch based upon the result. This option is only meaningful on architectures that support such instructions, which include x86, PowerPC, IA-64 and S/390. +The default is @option{-fbranch-count-reg}, enabled when +@option{-fstrength-reduce} is enabled. + @item -fno-function-cse @opindex fno-function-cse Do not put function addresses in registers; make each instruction that @@ -3498,87 +3637,28 @@ This option results in less efficient code, but some strange hacks that alter the assembler output may be confused by the optimizations performed when this option is not used. -@item -ffast-math -@opindex ffast-math -Sets @option{-fno-math-errno}, @option{-funsafe-math-optimizations}, and @* -@option{-fno-trapping-math}. - -This option causes the preprocessor macro @code{__FAST_MATH__} to be defined. - -This option should never be turned on by any @option{-O} option since -it can result in incorrect output for programs which depend on -an exact implementation of IEEE or ISO rules/specifications for -math functions. - -@item -fno-math-errno -@opindex fno-math-errno -Do not set ERRNO after calling math functions that are executed -with a single instruction, e.g., sqrt. A program that relies on -IEEE exceptions for math error handling may want to use this flag -for speed while maintaining IEEE arithmetic compatibility. - -This option should never be turned on by any @option{-O} option since -it can result in incorrect output for programs which depend on -an exact implementation of IEEE or ISO rules/specifications for -math functions. - -The default is @option{-fmath-errno}. - -@item -funsafe-math-optimizations -@opindex funsafe-math-optimizations -Allow optimizations for floating-point arithmetic that (a) assume -that arguments and results are valid and (b) may violate IEEE or -ANSI standards. When used at link-time, it may include libraries -or startup files that change the default FPU control word or other -similar optimizations. +The default is @option{-ffunction-cse} -This option should never be turned on by any @option{-O} option since -it can result in incorrect output for programs which depend on -an exact implementation of IEEE or ISO rules/specifications for -math functions. +@item -fno-zero-initialized-in-bss +@opindex fno-zero-initialized-in-bss +If the target supports a BSS section, GCC by default puts variables that +are initialized to zero into BSS@. This can save space in the resulting +code. -The default is @option{-fno-unsafe-math-optimizations}. +This option turns off this behavior because some programs explicitly +rely on variables going to the data section. E.g., so that the +resulting executable can find the beginning of that section and/or make +assumptions based on that. -@item -fno-trapping-math -@opindex fno-trapping-math -Compile code assuming that floating-point operations cannot generate -user-visible traps. Setting this option may allow faster code -if one relies on ``non-stop'' IEEE arithmetic, for example. +The default is @option{-fzero-initialized-in-bss}. -This option should never be turned on by any @option{-O} option since -it can result in incorrect output for programs which depend on -an exact implementation of IEEE or ISO rules/specifications for -math functions. - -The default is @option{-ftrapping-math}. - -@item -fbounds-check -@opindex fbounds-check -For front-ends that support it, generate additional code to check that -indices used to access arrays are within the declared range. This is -currenly only supported by the Java and Fortran 77 front-ends, where -this option defaults to true and false respectively. - -@end table - -The following options control specific optimizations. The @option{-O2} -option turns on all of these optimizations except @option{-funroll-loops} -and @option{-funroll-all-loops}. On most machines, the @option{-O} option -turns on the @option{-fthread-jumps} and @option{-fdelayed-branch} options, -but specific machines may handle it differently. - -You can use the following flags in the rare cases when ``fine-tuning'' -of optimizations to be performed is desired. - -Not all of the optimizations performed by GCC have @option{-f} options -to control them. - -@table @gcctabopt @item -fstrength-reduce @opindex fstrength-reduce Perform the optimizations of loop strength reduction and elimination of iteration variables. +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}. + @item -fthread-jumps @opindex fthread-jumps Perform optimizations where we check to see if a jump branches to a @@ -3587,6 +3667,8 @@ so, the first branch is redirected to either the destination of the second branch or a point immediately following it, depending on whether the condition is known to be true or false. +Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}. + @item -fcse-follow-jumps @opindex fcse-follow-jumps In common subexpression elimination, scan through jump instructions @@ -3595,6 +3677,8 @@ example, when CSE encounters an @code{if} statement with an @code{else} clause, CSE will follow the jump when the condition tested is false. +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}. + @item -fcse-skip-blocks @opindex fcse-skip-blocks This is similar to @option{-fcse-follow-jumps}, but causes CSE to @@ -3603,15 +3687,21 @@ encounters a simple @code{if} statement with no else clause, @option{-fcse-skip-blocks} causes CSE to follow the jump around the body of the @code{if}. +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}. + @item -frerun-cse-after-loop @opindex frerun-cse-after-loop Re-run common subexpression elimination after loop optimizations has been performed. +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}. + @item -frerun-loop-opt @opindex frerun-loop-opt Run the loop optimizer twice. +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}. + @item -fgcse @opindex fgcse Perform a global common subexpression elimination pass. @@ -3619,9 +3709,11 @@ This pass also performs global constant and copy propagation. @emph{Note:} When compiling a program using computed gotos, a GCC extension, you may get better runtime performance if you disable -the global common subexpression elmination pass by adding +the global common subexpression elimination pass by adding @option{-fno-gcse} to the command line. +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}. + @item -fgcse-lm @opindex fgcse-lm When @option{-fgcse-lm} is enabled, global common subexpression elimination will @@ -3629,6 +3721,8 @@ attempt to move loads which are only killed by stores into themselves. This allows a loop containing a load/store sequence to be changed to a load outside the loop, and a copy/store within the loop. +Enabled by default when gcse is enabled. + @item -fgcse-sm @opindex fgcse-sm When @option{-fgcse-sm} is enabled, A store motion pass is run after global common @@ -3636,6 +3730,39 @@ subexpression elimination. This pass will attempt to move stores out of loops. When used in conjunction with @option{-fgcse-lm}, loops containing a load/store sequence can be changed to a load before the loop and a store after the loop. +Enabled by default when gcse is enabled. + +@item -floop-optimize +@opindex floop-optimize +Perform loop optimizations: move constant expressions out of loops, simplify +exit test conditions and optionally do strength-reduction and loop unrolling as +well. + +Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}. + +@item -fcrossjumping +@opindex crossjumping +Perform cross-jumping transformation. This transformation unifies equivalent code and save code size. The +resulting code may or may not perform better than without cross-jumping. + +Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}. + +@item -fif-conversion +@opindex if-conversion +Attempt to transform conditional jumps into branch-less equivalents. This +include use of conditional moves, min, max, set flags and abs instructions, and +some tricks doable by standard arithmetics. The use of conditional execution +on chips where it is available is controlled by @code{if-conversion2}. + +Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}. + +@item -fif-conversion2 +@opindex if-conversion2 +Use conditional execution (where available) to transform conditional jumps into +branch-less equivalents. + +Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}. + @item -fdelete-null-pointer-checks @opindex fdelete-null-pointer-checks Use global dataflow analysis to identify and eliminate useless checks @@ -3648,10 +3775,14 @@ safely dereference null pointers. Use @option{-fno-delete-null-pointer-checks} to disable this optimization for programs which depend on that behavior. +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}. + @item -fexpensive-optimizations @opindex fexpensive-optimizations Perform a number of minor optimizations that are relatively expensive. +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}. + @item -foptimize-register-move @itemx -fregmove @opindex foptimize-register-move @@ -3659,18 +3790,21 @@ Perform a number of minor optimizations that are relatively expensive. Attempt to reassign register numbers in move instructions and as operands of other simple instructions in order to maximize the amount of register tying. This is especially helpful on machines with two-operand -instructions. GCC enables this optimization by default with @option{-O2} -or higher. +instructions. Note @option{-fregmove} and @option{-foptimize-register-move} are the same optimization. +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}. + @item -fdelayed-branch @opindex fdelayed-branch If supported for the target machine, attempt to reorder instructions to exploit instruction slots available after delayed branch instructions. +Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}. + @item -fschedule-insns @opindex fschedule-insns If supported for the target machine, attempt to reorder instructions to @@ -3679,6 +3813,8 @@ helps machines that have slow floating point or memory load instructions by allowing other instructions to be issued until the result of the load or floating point instruction is required. +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}. + @item -fschedule-insns2 @opindex fschedule-insns2 Similar to @option{-fschedule-insns}, but requests an additional pass of @@ -3686,6 +3822,8 @@ instruction scheduling after register allocation has been done. This is especially useful on machines with a relatively small number of registers and where memory load instructions take more than one cycle. +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}. + @item -fno-sched-interblock @opindex fno-sched-interblock Don't schedule instructions across basic blocks. This is normally @@ -3710,28 +3848,6 @@ Allow speculative motion of more load instructions. This only makes sense when scheduling before register allocation, i.e.@: with @option{-fschedule-insns} or at @option{-O2} or higher. -@item -ffunction-sections -@itemx -fdata-sections -@opindex ffunction-sections -@opindex fdata-sections -Place each function or data item into its own section in the output -file if the target supports arbitrary sections. The name of the -function or the name of the data item determines the section's name -in the output file. - -Use these options on systems where the linker can perform optimizations -to improve locality of reference in the instruction space. HPPA -processors running HP-UX and Sparc processors running Solaris 2 have -linkers with such optimizations. Other systems using the ELF object format -as well as AIX may have these optimizations in the future. - -Only use these options when there are significant benefits from doing -so. When you specify these options, the assembler and linker will -create larger object and executable files and will also be slower. -You will not be able to use @code{gprof} on all systems if you -specify this option and you may have problems with debugging if -you specify both this option and @option{-g}. - @item -fcaller-saves @opindex fcaller-saves Enable values to be allocated in registers that will be clobbered by @@ -3742,27 +3858,7 @@ seems to result in better code than would otherwise be produced. This option is always enabled by default on certain machines, usually those which have no call-preserved registers to use instead. -For all machines, optimization level 2 and higher enables this flag by -default. - -@item -funroll-loops -@opindex funroll-loops -Unroll loops whose number of iterations can be determined at compile -time or upon entry to the loop. @option{-funroll-loops} implies both -@option{-fstrength-reduce} and @option{-frerun-cse-after-loop}. This -option makes code larger, and may or may not make it run faster. - -@item -funroll-all-loops -@opindex funroll-all-loops -Unroll all loops, even if their number of iterations is uncertain when -the loop is entered. This usually makes programs run more slowly. -@option{-funroll-all-loops} implies the same options as -@option{-funroll-loops}, - -@item -fprefetch-loop-arrays -@opindex fprefetch-loop-arrays -If supported by the target machine, generate instructions to prefetch -memory to improve the performance of loops that access large arrays. +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}. @item -fmove-all-movables @opindex fmove-all-movables @@ -3800,27 +3896,10 @@ between @option{-fno-peephole} and @option{-fno-peephole2} is in how they are implemented in the compiler; some targets use one, some use the other, a few use both. -@item -fbranch-probabilities -@opindex fbranch-probabilities -After running a program compiled with @option{-fprofile-arcs} -(@pxref{Debugging Options,, Options for Debugging Your Program or -@command{gcc}}), you can compile it a second time using -@option{-fbranch-probabilities}, to improve optimizations based on -the number of times each branch was taken. When the program -compiled with @option{-fprofile-arcs} exits it saves arc execution -counts to a file called @file{@var{sourcename}.da} for each source -file The information in this data file is very dependent on the -structure of the generated code, so you must use the same source code -and the same optimization options for both compilations. - -With @option{-fbranch-probabilities}, GCC puts a @samp{REG_EXEC_COUNT} -note on the first instruction of each basic block, and a -@samp{REG_BR_PROB} note on each @samp{JUMP_INSN} and @samp{CALL_INSN}. -These can be used to improve optimization. Currently, they are only -used in one place: in @file{reorg.c}, instead of guessing which path a -branch is mostly to take, the @samp{REG_BR_PROB} values are used to -exactly determine which path is taken more often. +@option{-fpeephole} is enabled by default. +@option{-fpeephole2} enabled at levels @option{-O2}, @option{-O3}, @option{-Os}. +@item -fbranch-probabilities @item -fno-guess-branch-probability @opindex fno-guess-branch-probability Do not guess branch probabilities using a randomized model. @@ -3837,6 +3916,30 @@ non-determinism is of paramount import. This switch allows users to reduce non-determinism, possibly at the expense of inferior optimization. +The default is @option{-fguess-branch-probability} at levels +@option{-O}, @option{-O2}, @option{-O3}, @option{-Os}. + +@item -freorder-blocks +@opindex freorder-blocks +Reorder basic blocks in the compiled function in order to reduce number of +taken branches and improve code locality. + +Enabled at levels @option{-O2}, @option{-O3}. + +@item -freorder-functions +@opindex freorder-functions +Reorder basic blocks in the compiled function in order to reduce number of +taken branches and improve code locality. This is implemented by using special +subsections @code{text.hot} for most frequently executed functions and +@code{text.unlikely} for unlikely executed functions. Reordering is done by +the linker so object file format must support named sections and linker must +place them in a reasonable way. + +Also profile feedback must be available in to make this option effective. See +@option{-fprofile-arcs} for details. + +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}. + @item -fstrict-aliasing @opindex fstrict-aliasing Allows the compiler to assume the strictest aliasing rules applicable to @@ -3882,6 +3985,8 @@ node, an alias set for the node. Nodes in different alias sets are not allowed to alias. For an example, see the C front-end function @code{c_get_alias_set}. +Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}. + @item -falign-functions @itemx -falign-functions=@var{n} @opindex falign-functions @@ -3897,7 +4002,9 @@ equivalent and mean that functions will not be aligned. Some assemblers only support this flag when @var{n} is a power of two; in that case, it is rounded up. -If @var{n} is not specified, use a machine-dependent default. +If @var{n} is not specified or is zero, use a machine-dependent default. + +Enabled at levels @option{-O2}, @option{-O3}. @item -falign-labels @itemx -falign-labels=@var{n} @@ -3907,11 +4014,16 @@ Align all branch targets to a power-of-two boundary, skipping up to make code slower, because it must insert dummy operations for when the branch target is reached in the usual flow of the code. +@option{-fno-align-labels} and @option{-falign-labels=1} are +equivalent and mean that labels will not be aligned. + If @option{-falign-loops} or @option{-falign-jumps} are applicable and are greater than this value, then their values are used instead. -If @var{n} is not specified, use a machine-dependent default which is -very likely to be @samp{1}, meaning no alignment. +If @var{n} is not specified or is zero, use a machine-dependent default +which is very likely to be @samp{1}, meaning no alignment. + +Enabled at levels @option{-O2}, @option{-O3}. @item -falign-loops @itemx -falign-loops=@var{n} @@ -3921,7 +4033,12 @@ like @option{-falign-functions}. The hope is that the loop will be executed many times, which will make up for any execution of the dummy operations. -If @var{n} is not specified, use a machine-dependent default. +@option{-fno-align-loops} and @option{-falign-loops=1} are +equivalent and mean that loops will not be aligned. + +If @var{n} is not specified or is zero, use a machine-dependent default. + +Enabled at levels @option{-O2}, @option{-O3}. @item -falign-jumps @itemx -falign-jumps=@var{n} @@ -3931,7 +4048,224 @@ where the targets can only be reached by jumping, skipping up to @var{n} bytes like @option{-falign-functions}. In this case, no dummy operations need be executed. -If @var{n} is not specified, use a machine-dependent default. +@option{-fno-align-jumps} and @option{-falign-jumps=1} are +equivalent and mean that loops will not be aligned. + +If @var{n} is not specified or is zero, use a machine-dependent default. + +Enabled at levels @option{-O2}, @option{-O3}. + +@item -frename-registers +@opindex frename-registers +Attempt to avoid false dependencies in scheduled code by making use +of registers left over after register allocation. This optimization +will most benefit processors with lots of registers. It can, however, +make debugging impossible, since variables will no longer stay in +a ``home register''. + +Enabled at levels @option{-O3}. + +@item -fno-cprop-registers +@opindex fno-cprop-registers +After register allocation and post-register allocation instruction splitting, +we perform a copy-propagation pass to try to reduce scheduling dependencies +and occasionally eliminate the copy. + +Disabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}. + +@end table + +The following options control compiler behavior regarding floating +point arithmetic. These options trade off between speed and +correctness. All must be specifically enabled. + +@table @gcctabopt +@item -ffloat-store +@opindex ffloat-store +Do not store floating point variables in registers, and inhibit other +options that might change whether a floating point value is taken from a +register or memory. + +@cindex floating point precision +This option prevents undesirable excess precision on machines such as +the 68000 where the floating registers (of the 68881) keep more +precision than a @code{double} is supposed to have. Similarly for the +x86 architecture. For most programs, the excess precision does only +good, but a few programs rely on the precise definition of IEEE floating +point. Use @option{-ffloat-store} for such programs, after modifying +them to store all pertinent intermediate computations into variables. + +@item -ffast-math +@opindex ffast-math +Sets @option{-fno-math-errno}, @option{-funsafe-math-optimizations}, @* +@option{-fno-trapping-math}, @option{-ffinite-math-only} and @* +@option{-fno-signaling-nans}. + +This option causes the preprocessor macro @code{__FAST_MATH__} to be defined. + +This option should never be turned on by any @option{-O} option since +it can result in incorrect output for programs which depend on +an exact implementation of IEEE or ISO rules/specifications for +math functions. + +@item -fno-math-errno +@opindex fno-math-errno +Do not set ERRNO after calling math functions that are executed +with a single instruction, e.g., sqrt. A program that relies on +IEEE exceptions for math error handling may want to use this flag +for speed while maintaining IEEE arithmetic compatibility. + +This option should never be turned on by any @option{-O} option since +it can result in incorrect output for programs which depend on +an exact implementation of IEEE or ISO rules/specifications for +math functions. + +The default is @option{-fmath-errno}. + +@item -funsafe-math-optimizations +@opindex funsafe-math-optimizations +Allow optimizations for floating-point arithmetic that (a) assume +that arguments and results are valid and (b) may violate IEEE or +ANSI standards. When used at link-time, it may include libraries +or startup files that change the default FPU control word or other +similar optimizations. + +This option should never be turned on by any @option{-O} option since +it can result in incorrect output for programs which depend on +an exact implementation of IEEE or ISO rules/specifications for +math functions. + +The default is @option{-fno-unsafe-math-optimizations}. + +@item -ffinite-math-only +@opindex ffinite-math-only +Allow optimizations for floating-point arithmetic that assume +that arguments and results are not NaNs or +-Infs. + +This option should never be turned on by any @option{-O} option since +it can result in incorrect output for programs which depend on +an exact implementation of IEEE or ISO rules/specifications. + +The default is @option{-fno-finite-math-only}. + +@item -fno-trapping-math +@opindex fno-trapping-math +Compile code assuming that floating-point operations cannot generate +user-visible traps. These traps include division by zero, overflow, +underflow, inexact result and invalid operation. This option implies +@option{-fno-signaling-nans}. Setting this option may allow faster +code if one relies on ``non-stop'' IEEE arithmetic, for example. + +This option should never be turned on by any @option{-O} option since +it can result in incorrect output for programs which depend on +an exact implementation of IEEE or ISO rules/specifications for +math functions. + +The default is @option{-ftrapping-math}. + +@item -fsignaling-nans +@opindex fsignaling-nans +Compile code assuming that IEEE signaling NaNs may generate user-visible +traps during floating-point operations. Setting this option disables +optimizations that may change the number of exceptions visible with +signaling NaNs. This option implies @option{-ftrapping-math}. + +This option causes the preprocessor macro @code{__SUPPORT_SNAN__} to +be defined. + +The default is @option{-fno-signaling-nans}. + +This option is experimental and does not currently guarantee to +disable all GCC optimizations that affect signaling NaN behavior. + +@item -fsingle-precision-constant +@opindex fsingle-precision-constant +Treat floating point constant as single precision constant instead of +implicitly converting it to double precision constant. + + +@end table + +The following options control optimizations that may improve +performance, but are not enabled by any @option{-O} options. This +section includes experimental options that may produce broken code. + +@table @gcctabopt +@item -fbranch-probabilities +@opindex fbranch-probabilities +After running a program compiled with @option{-fprofile-arcs} +(@pxref{Debugging Options,, Options for Debugging Your Program or +@command{gcc}}), you can compile it a second time using +@option{-fbranch-probabilities}, to improve optimizations based on +the number of times each branch was taken. When the program +compiled with @option{-fprofile-arcs} exits it saves arc execution +counts to a file called @file{@var{sourcename}.da} for each source +file The information in this data file is very dependent on the +structure of the generated code, so you must use the same source code +and the same optimization options for both compilations. + +With @option{-fbranch-probabilities}, GCC puts a +@samp{REG_BR_PROB} note on each @samp{JUMP_INSN} and @samp{CALL_INSN}. +These can be used to improve optimization. Currently, they are only +used in one place: in @file{reorg.c}, instead of guessing which path a +branch is mostly to take, the @samp{REG_BR_PROB} values are used to +exactly determine which path is taken more often. + +@item -fnew-ra +@opindex fnew-ra +Use a graph coloring register allocator. Currently this option is meant +for testing, so we are interested to hear about miscompilations with +@option{-fnew-ra}. + +@item -ftracer +@opindex ftracer +Perform tail duplication to enlarge superblock size. This transformation +simplifies the control flow of the function allowing other optimizations to do +better job. + +@item -funroll-loops +@opindex funroll-loops +Unroll loops whose number of iterations can be determined at compile +time or upon entry to the loop. @option{-funroll-loops} implies both +@option{-fstrength-reduce} and @option{-frerun-cse-after-loop}. This +option makes code larger, and may or may not make it run faster. + +@item -funroll-all-loops +@opindex funroll-all-loops +Unroll all loops, even if their number of iterations is uncertain when +the loop is entered. This usually makes programs run more slowly. +@option{-funroll-all-loops} implies the same options as +@option{-funroll-loops}, + +@item -fprefetch-loop-arrays +@opindex fprefetch-loop-arrays +If supported by the target machine, generate instructions to prefetch +memory to improve the performance of loops that access large arrays. + +Disabled at level @option{-Os}. + +@item -ffunction-sections +@itemx -fdata-sections +@opindex ffunction-sections +@opindex fdata-sections +Place each function or data item into its own section in the output +file if the target supports arbitrary sections. The name of the +function or the name of the data item determines the section's name +in the output file. + +Use these options on systems where the linker can perform optimizations +to improve locality of reference in the instruction space. Most systems +using the ELF object format and SPARC processors running Solaris 2 have +linkers with such optimizations. AIX may have these optimizations in +the future. + + +Only use these options when there are significant benefits from doing +so. When you specify these options, the assembler and linker will +create larger object and executable files and will also be slower. +You will not be able to use @code{gprof} on all systems if you +specify this option and you may have problems with debugging if +you specify both this option and @option{-g}. @item -fssa @opindex fssa @@ -3950,24 +4284,6 @@ Perform Sparse Conditional Constant Propagation in SSA form. Requires Perform aggressive dead-code elimination in SSA form. Requires @option{-fssa}. Like @option{-fssa}, this is an experimental feature. -@item -fsingle-precision-constant -@opindex fsingle-precision-constant -Treat floating point constant as single precision constant instead of -implicitly converting it to double precision constant. - -@item -frename-registers -@opindex frename-registers -Attempt to avoid false dependencies in scheduled code by making use -of registers left over after register allocation. This optimization -will most benefit processors with lots of registers. It can, however, -make debugging impossible, since variables will no longer stay in -a ``home register''. - -@item -fno-cprop-registers -@opindex fno-cprop-registers -After register allocation and post-register allocation instruction splitting, -we perform a copy-propagation pass to try to reduce scheduling dependencies -and occasionally eliminate the copy. @item --param @var{name}=@var{value} @opindex param @@ -3981,6 +4297,13 @@ In each case, the @var{value} is an integer. The allowable choices for @var{name} are given in the following table: @table @gcctabopt +@item max-crossjump-edges +The maximum number of incoming edges to consider for crossjumping. +The algorithm used by @option{-fcrossjumping} is @math{O(N^2)} in +the number of edges incoming to each block. Increasing values mean +more aggressive optimization, making the compile time increase with +probably small improvement in executable size. + @item max-delay-slot-insn-search The maximum number of instructions to consider when looking for an instruction to fill a delay slot. If more than this arbitrary number of @@ -4012,10 +4335,133 @@ before flushing the current state and starting over. Large functions with few branches or calls can create excessively large lists which needlessly consume memory and resources. +@item max-inline-insns-single +Several parameters control the tree inliner used in gcc. +This number sets the maximum number of instructions (counted in gcc's +internal representation) in a single function that the tree inliner +will consider for inlining. This only affects functions declared +inline and methods implemented in a class declaration (C++). +The default value is 300. + +@item max-inline-insns-auto +When you use @option{-finline-functions} (included in @option{-O3}), +a lot of functions that would otherwise not be considered for inlining +by the compiler will be investigated. To those functions, a different +(more restrictive) limit compared to functions declared inline can +be applied. +The default value is 300. + @item max-inline-insns -If an function contains more than this many instructions, it -will not be inlined. This option is precisely equivalent to -@option{-finline-limit}. +The tree inliner does decrease the allowable size for single functions +to be inlined after we already inlined the number of instructions +given here by repeated inlining. This number should be a factor of +two or more larger than the single function limit. +Higher numbers result in better runtime performance, but incur higher +compile-time resource (CPU time, memory) requirements and result in +larger binaries. Very high values are not advisable, as too large +binaries may adversely affect runtime performance. +The default value is 600. + +@item max-inline-slope +After exceeding the maximum number of inlined instructions by repeated +inlining, a linear function is used to decrease the allowable size +for single functions. The slope of that function is the negative +reciprocal of the number specified here. +The default value is 32. + +@item min-inline-insns +The repeated inlining is throttled more and more by the linear function +after exceeding the limit. To avoid too much throttling, a minimum for +this function is specified here to allow repeated inlining for very small +functions even when a lot of repeated inlining already has been done. +The default value is 130. + +@item max-inline-insns-rtl +For languages that use the RTL inliner (this happens at a later stage +than tree inlining), you can set the maximum allowable size (counted +in RTL instructions) for the RTL inliner with this parameter. +The default value is 600. + + +@item max-unrolled-insns +The maximum number of instructions that a loop should have if that loop +is unrolled, and if the loop is unrolled, it determines how many times +the loop code is unrolled. + +@item hot-bb-count-fraction +Select fraction of the maximal count of repetitions of basic block in program +given basic block needs to have to be considered hot. + +@item hot-bb-frequency-fraction +Select fraction of the maximal frequency of executions of basic block in +function given basic block needs to have to be considered hot + +@item tracer-dynamic-coverage +@itemx tracer-dynamic-coverage-feedback + +This value is used to limit superblock formation once the given percentage of +executed instructions is covered. This limits unnecessary code size +expansion. + +The @option{tracer-dynamic-coverage-feedback} is used only when profile +feedback is available. The real profiles (as opposed to statically estimated +ones) are much less balanced allowing the threshold to be larger value. + +@item tracer-max-code-growth +Stop tail duplication once code growth has reached given percentage. This is +rather hokey argument, as most of the duplicates will be eliminated later in +cross jumping, so it may be set to much higher values than is the desired code +growth. + +@item tracer-min-branch-ratio + +Stop reverse growth when the reverse probability of best edge is less than this +threshold (in percent). + +@item tracer-min-branch-ratio +@itemx tracer-min-branch-ratio-feedback + +Stop forward growth if the best edge do have probability lower than this +threshold. + +Similarly to @option{tracer-dynamic-coverage} two values are present, one for +compilation for profile feedback and one for compilation without. The value +for compilation with profile feedback needs to be more conservative (higher) in +order to make tracer effective. + +@item ggc-min-expand + +GCC uses a garbage collector to manage its own memory allocation. This +parameter specifies the minimum percentage by which the garbage +collector's heap should be allowed to expand between collections. +Tuning this may improve compilation speed; it has no effect on code +generation. + +The default is 30% + 70% * (RAM/1GB) with an upper bound of 100% when +RAM >= 1GB. If @code{getrlimit} is available, the notion of "RAM" is +the smallest of actual RAM, RLIMIT_RSS, RLIMIT_DATA and RLIMIT_AS. If +GCC is not able to calculate RAM on a particular platform, the lower +bound of 30% is used. Setting this parameter and +@option{ggc-min-heapsize} to zero causes a full collection to occur at +every opportunity. This is extremely slow, but can be useful for +debugging. + +@item ggc-min-heapsize + +Minimum size of the garbage collector's heap before it begins bothering +to collect garbage. The first collection occurs after the heap expands +by @option{ggc-min-expand}% beyond @option{ggc-min-heapsize}. Again, +tuning this may improve compilation speed, and has no effect on code +generation. + +The default is RAM/8, with a lower bound of 4096 (four megabytes) and an +upper bound of 131072 (128 megabytes). If @code{getrlimit} is +available, the notion of "RAM" is the smallest of actual RAM, +RLIMIT_RSS, RLIMIT_DATA and RLIMIT_AS. If GCC is not able to calculate +RAM on a particular platform, the lower bound is used. Setting this +parameter very large effectively disables garbage collection. Setting +this parameter and @option{ggc-min-expand} to zero causes a full +collection to occur at every opportunity. @end table @end table @@ -4287,7 +4733,7 @@ If a standard system include directory, or a directory specified with option will be ignored. The directory will still be searched but as a system directory at its normal position in the system include chain. This is to ensure that GCC's procedure to fix buggy system headers and -the ordering for the include_next directive are not inadvertantly changed. +the ordering for the include_next directive are not inadvertently changed. If you really need to change the search order for system directories, use the @option{-nostdinc} and/or @option{-isystem} options. @@ -4377,6 +4823,7 @@ are processed in order, from left to right. @node Spec Files @section Specifying subprocesses and the switches to pass to them @cindex Spec Files + @command{gcc} is a driver program. It performs its job by invoking a sequence of other programs to do the work of compiling, assembling and linking. GCC interprets its command-line parameters and uses these to @@ -4725,6 +5172,41 @@ Substitute the variable part of a matched option. See below. Note that each comma in the substituted string is replaced by a single space. +@item %:@var{function}(@var{args}) +Call the named function @var{function}, passing it @var{args}. +@var{args} is first processed as a nested spec string, then split +into an argument vector in the usual fashion. The function returns +a string which is processed as if it had appeared literally as part +of the current spec. + +The following built-in spec functions are provided: + +@table @code +@item @code{if-exists} +The @code{if-exists} spec function takes one argument, an absolute +pathname to a file. If the file exists, @code{if-exists} returns the +pathname. Here is a small example of its usage: + +@smallexample +*startfile: +crt0%O%s %:if-exists(crti%O%s) crtbegin%O%s +@end smallexample + +@item @code{if-exists-else} +The @code{if-exists-else} spec function is similar to the @code{if-exists} +spec function, except that it takes two arguments. The first argument is +an absolute pathname to a file. If the file exists, @code{if-exists-else} +returns the pathname. If it does not exist, it returns the second argument. +This way, @code{if-exists-else} can be used to select one file or another, +based on the existence of the first. Here is a small example of its usage: + +@smallexample +*startfile: +crt0%O%s %:if-exists(crti%O%s) \ +%:if-exists-else(crtbeginT%O%s crtbegin%O%s) +@end smallexample +@end table + @item %@{@code{S}@} Substitutes the @code{-S} switch, if that switch was given to GCC@. If that switch was not specified, this substitutes nothing. Note that @@ -4846,22 +5328,16 @@ proper position among the other output files. @cindex compiler version, specifying @cindex target machine, specifying -By default, GCC compiles code for the same type of machine that you -are using. However, it can also be installed as a cross-compiler, to -compile for some other type of machine. In fact, several different -configurations of GCC, for different target machines, can be -installed side by side. Then you specify which one to use with the -@option{-b} option. - -In addition, older and newer versions of GCC can be installed side -by side. One of them (probably the newest) will be the default, but -you may sometimes wish to use another. +The usual way to run GCC is to run the executable called @file{gcc}, or +@file{<machine>-gcc} when cross-compiling, or +@file{<machine>-gcc-<version>} to run a version other than the one that +was installed last. Sometimes this is inconvenient, so GCC provides +options that will switch to another cross-compiler or version. @table @gcctabopt @item -b @var{machine} @opindex b The argument @var{machine} specifies the target machine for compilation. -This is useful when you have installed GCC as a cross-compiler. The value to use for @var{machine} is the same as was specified as the machine type when configuring GCC as a cross-compiler. For @@ -4869,61 +5345,16 @@ example, if a cross-compiler was configured with @samp{configure i386v}, meaning to compile for an 80386 running System V, then you would specify @option{-b i386v} to run that cross compiler. -When you do not specify @option{-b}, it normally means to compile for -the same type of machine that you are using. - @item -V @var{version} @opindex V The argument @var{version} specifies which version of GCC to run. This is useful when multiple versions are installed. For example, @var{version} might be @samp{2.0}, meaning to run GCC version 2.0. - -The default version, when you do not specify @option{-V}, is the last -version of GCC that you installed. @end table -The @option{-b} and @option{-V} options actually work by controlling part of -the file name used for the executable files and libraries used for -compilation. A given version of GCC, for a given target machine, is -normally kept in the directory @file{/usr/local/lib/gcc-lib/@var{machine}/@var{version}}. - -Thus, sites can customize the effect of @option{-b} or @option{-V} either by -changing the names of these directories or adding alternate names (or -symbolic links). If in directory @file{/usr/local/lib/gcc-lib/} the -file @file{80386} is a link to the file @file{i386v}, then @option{-b -80386} becomes an alias for @option{-b i386v}. - -In one respect, the @option{-b} or @option{-V} do not completely change -to a different compiler: the top-level driver program @command{gcc} -that you originally invoked continues to run and invoke the other -executables (preprocessor, compiler per se, assembler and linker) -that do the real work. However, since no real work is done in the -driver program, it usually does not matter that the driver program -in use is not the one for the specified target. It is common for the -interface to the other executables to change incompatibly between -compiler versions, so unless the version specified is very close to that -of the driver (for example, @option{-V 3.0} with a driver program from GCC -version 3.0.1), use of @option{-V} may not work; for example, using -@option{-V 2.95.2} will not work with a driver program from GCC 3.0. - -The only way that the driver program depends on the target machine is -in the parsing and handling of special machine-specific options. -However, this is controlled by a file which is found, along with the -other executables, in the directory for the specified version and -target machine. As a result, a single installed driver program adapts -to any specified target machine, and sufficiently similar compiler -versions. - -The driver program executable does control one significant thing, -however: the default version and target machine. Therefore, you can -install different instances of the driver program, compiled for -different targets or versions, under different names. - -For example, if the driver for version 2.0 is installed as @command{ogcc} -and that for version 2.1 is installed as @command{gcc}, then the command -@command{gcc} will use version 2.1 by default, while @command{ogcc} will use -2.0 by default. However, you can choose either version with either -command with the @option{-V} option. +The @option{-V} and @option{-b} options work by running the +@file{<machine>-gcc-<version>} executable, so there's no real reason to +use them if you can just run that directly. @node Submodel Options @section Hardware Models and Configurations @@ -4956,14 +5387,13 @@ that macro, which enables you to change the defaults. * M68hc1x Options:: * VAX Options:: * SPARC Options:: -* Convex Options:: -* AMD29K Options:: * ARM Options:: * MN10200 Options:: * MN10300 Options:: * M32R/D Options:: * M88K Options:: * RS/6000 and PowerPC Options:: +* Darwin Options:: * RT Options:: * MIPS Options:: * i386 and x86-64 Options:: @@ -4971,7 +5401,6 @@ that macro, which enables you to change the defaults. * Intel 960 Options:: * DEC Alpha Options:: * DEC Alpha/VMS Options:: -* Clipper Options:: * H8/300 Options:: * SH Options:: * System V Options:: @@ -4989,6 +5418,7 @@ that macro, which enables you to change the defaults. * PDP-11 Options:: * Xstormy16 Options:: * Xtensa Options:: +* FRV Options:: @end menu @node M680x0 Options @@ -5187,11 +5617,31 @@ when the compiler is configured for 68HC11-based systems. Generate output for a 68HC12. This is the default when the compiler is configured for 68HC12-based systems. +@item -m68S12 +@itemx -m68hcs12 +@opindex m68S12 +@opindex m68hcs12 +Generate output for a 68HCS12. + @item -mauto-incdec @opindex mauto-incdec Enable the use of 68HC12 pre and post auto-increment and auto-decrement addressing modes. +@item -minmax +@itemx -nominmax +@opindex minmax +@opindex mnominmax +Enable the use of 68HC12 min and max instructions. + +@item -mlong-calls +@itemx -mno-long-calls +@opindex mlong-calls +@opindex mno-long-calls +Treat all calls as being far away (near). If calls are assumed to be +far away, the compiler will use the @code{call} instruction to +call a function and the @code{rtc} instruction for returning. + @item -mshort @opindex mshort Consider type @code{int} to be 16 bits wide, like @code{short int}. @@ -5325,7 +5775,7 @@ With @option{-mfaster-structs}, the compiler assumes that structures should have 8 byte alignment. This enables the use of pairs of @code{ldd} and @code{std} instructions for copies in structure assignment, in place of twice as many @code{ld} and @code{st} pairs. -However, the use of this changed alignment directly violates the Sparc +However, the use of this changed alignment directly violates the SPARC ABI@. Thus, it's intended only for use on targets where the developer acknowledges that their resulting code will not be directly in line with the rules of the ABI@. @@ -5357,11 +5807,11 @@ They have been replaced with @option{-mcpu=xxx}. These two options select the processor for which the code is optimized. With @option{-mcypress} (the default), the compiler optimizes code for the -Cypress CY7C602 chip, as used in the SparcStation/SparcServer 3xx series. -This is also appropriate for the older SparcStation 1, 2, IPX etc. +Cypress CY7C602 chip, as used in the SPARCStation/SPARCServer 3xx series. +This is also appropriate for the older SPARCStation 1, 2, IPX etc. -With @option{-msupersparc} the compiler optimizes code for the SuperSparc cpu, as -used in the SparcStation 10, 1000 and 2000 series. This flag also enables use +With @option{-msupersparc} the compiler optimizes code for the SuperSPARC cpu, as +used in the SPARCStation 10, 1000 and 2000 series. This flag also enables use of the full SPARC v8 instruction set. These options are deprecated and will be deleted in a future GCC release. @@ -5373,7 +5823,8 @@ Set the instruction set, register set, and instruction scheduling parameters for machine type @var{cpu_type}. Supported values for @var{cpu_type} are @samp{v7}, @samp{cypress}, @samp{v8}, @samp{supersparc}, @samp{sparclite}, @samp{hypersparc}, @samp{sparclite86x}, @samp{f930}, @samp{f934}, -@samp{sparclet}, @samp{tsc701}, @samp{v9}, and @samp{ultrasparc}. +@samp{sparclet}, @samp{tsc701}, @samp{v9}, @samp{ultrasparc}, and +@samp{ultrasparc3}. Default instruction scheduling parameters are used for values that select an architecture and not an implementation. These are @samp{v7}, @samp{v8}, @@ -5387,7 +5838,7 @@ implementations. v8: supersparc, hypersparc sparclite: f930, f934, sparclite86x sparclet: tsc701 - v9: ultrasparc + v9: ultrasparc, ultrasparc3 @end smallexample @item -mtune=@var{cpu_type} @@ -5400,7 +5851,8 @@ The same values for @option{-mcpu=@var{cpu_type}} can be used for @option{-mtune=@var{cpu_type}}, but the only useful values are those that select a particular cpu implementation. Those are @samp{cypress}, @samp{supersparc}, @samp{hypersparc}, @samp{f930}, @samp{f934}, -@samp{sparclite86x}, @samp{tsc701}, and @samp{ultrasparc}. +@samp{sparclite86x}, @samp{tsc701}, @samp{ultrasparc}, and +@samp{ultrasparc3}. @end table @@ -5485,195 +5937,6 @@ when making stack frame references. Otherwise, assume no such offset is present. @end table -@node Convex Options -@subsection Convex Options -@cindex Convex options - -These @samp{-m} options are defined for Convex: - -@table @gcctabopt -@item -mc1 -@opindex mc1 -Generate output for C1. The code will run on any Convex machine. -The preprocessor symbol @code{__convex__c1__} is defined. - -@item -mc2 -@opindex mc2 -Generate output for C2. Uses instructions not available on C1. -Scheduling and other optimizations are chosen for max performance on C2. -The preprocessor symbol @code{__convex_c2__} is defined. - -@item -mc32 -@opindex mc32 -Generate output for C32xx. Uses instructions not available on C1. -Scheduling and other optimizations are chosen for max performance on C32. -The preprocessor symbol @code{__convex_c32__} is defined. - -@item -mc34 -@opindex mc34 -Generate output for C34xx. Uses instructions not available on C1. -Scheduling and other optimizations are chosen for max performance on C34. -The preprocessor symbol @code{__convex_c34__} is defined. - -@item -mc38 -@opindex mc38 -Generate output for C38xx. Uses instructions not available on C1. -Scheduling and other optimizations are chosen for max performance on C38. -The preprocessor symbol @code{__convex_c38__} is defined. - -@item -margcount -@opindex margcount -Generate code which puts an argument count in the word preceding each -argument list. This is compatible with regular CC, and a few programs -may need the argument count word. GDB and other source-level debuggers -do not need it; this info is in the symbol table. - -@item -mnoargcount -@opindex mnoargcount -Omit the argument count word. This is the default. - -@item -mvolatile-cache -@opindex mvolatile-cache -Allow volatile references to be cached. This is the default. - -@item -mvolatile-nocache -@opindex mvolatile-nocache -Volatile references bypass the data cache, going all the way to memory. -This is only needed for multi-processor code that does not use standard -synchronization instructions. Making non-volatile references to volatile -locations will not necessarily work. - -@item -mlong32 -@opindex mlong32 -Type long is 32 bits, the same as type int. This is the default. - -@item -mlong64 -@opindex mlong64 -Type long is 64 bits, the same as type long long. This option is useless, -because no library support exists for it. -@end table - -@node AMD29K Options -@subsection AMD29K Options -@cindex AMD29K options - -These @samp{-m} options are defined for the AMD Am29000: - -@table @gcctabopt -@item -mdw -@opindex mdw -@cindex DW bit (29k) -Generate code that assumes the @code{DW} bit is set, i.e., that byte and -halfword operations are directly supported by the hardware. This is the -default. - -@item -mndw -@opindex mndw -Generate code that assumes the @code{DW} bit is not set. - -@item -mbw -@opindex mbw -@cindex byte writes (29k) -Generate code that assumes the system supports byte and halfword write -operations. This is the default. - -@item -mnbw -@opindex mnbw -Generate code that assumes the systems does not support byte and -halfword write operations. @option{-mnbw} implies @option{-mndw}. - -@item -msmall -@opindex msmall -@cindex memory model (29k) -Use a small memory model that assumes that all function addresses are -either within a single 256 KB segment or at an absolute address of less -than 256k. This allows the @code{call} instruction to be used instead -of a @code{const}, @code{consth}, @code{calli} sequence. - -@item -mnormal -@opindex mnormal -Use the normal memory model: Generate @code{call} instructions only when -calling functions in the same file and @code{calli} instructions -otherwise. This works if each file occupies less than 256 KB but allows -the entire executable to be larger than 256 KB@. This is the default. - -@item -mlarge -@opindex mlarge -Always use @code{calli} instructions. Specify this option if you expect -a single file to compile into more than 256 KB of code. - -@item -m29050 -@opindex m29050 -@cindex processor selection (29k) -Generate code for the Am29050. - -@item -m29000 -@opindex m29000 -Generate code for the Am29000. This is the default. - -@item -mkernel-registers -@opindex mkernel-registers -@cindex kernel and user registers (29k) -Generate references to registers @code{gr64-gr95} instead of to -registers @code{gr96-gr127}. This option can be used when compiling -kernel code that wants a set of global registers disjoint from that used -by user-mode code. - -Note that when this option is used, register names in @samp{-f} flags -must use the normal, user-mode, names. - -@item -muser-registers -@opindex muser-registers -Use the normal set of global registers, @code{gr96-gr127}. This is the -default. - -@item -mstack-check -@itemx -mno-stack-check -@opindex mstack-check -@opindex mno-stack-check -@cindex stack checks (29k) -Insert (or do not insert) a call to @code{__msp_check} after each stack -adjustment. This is often used for kernel code. - -@item -mstorem-bug -@itemx -mno-storem-bug -@opindex mstorem-bug -@opindex mno-storem-bug -@cindex storem bug (29k) -@option{-mstorem-bug} handles 29k processors which cannot handle the -separation of a mtsrim insn and a storem instruction (most 29000 chips -to date, but not the 29050). - -@item -mno-reuse-arg-regs -@itemx -mreuse-arg-regs -@opindex mno-reuse-arg-regs -@opindex mreuse-arg-regs -@option{-mno-reuse-arg-regs} tells the compiler to only use incoming argument -registers for copying out arguments. This helps detect calling a function -with fewer arguments than it was declared with. - -@item -mno-impure-text -@itemx -mimpure-text -@opindex mno-impure-text -@opindex mimpure-text -@option{-mimpure-text}, used in addition to @option{-shared}, tells the compiler to -not pass @option{-assert pure-text} to the linker when linking a shared object. - -@item -msoft-float -@opindex msoft-float -Generate output containing library calls for floating point. -@strong{Warning:} the requisite libraries are not part of GCC@. -Normally the facilities of the machine's usual C compiler are used, but -this can't be done directly in cross-compilation. You must make your -own arrangements to provide suitable library functions for -cross-compilation. - -@item -mno-multm -@opindex mno-multm -Do not generate multm or multmu instructions. This is useful for some embedded -systems which do not have trap handlers for these instructions. -@end table - @node ARM Options @subsection ARM Options @cindex ARM options @@ -5803,7 +6066,7 @@ memory a feature of the ARM architecture allows a word load to be used, even if the address is unaligned, and the processor core will rotate the data as it is being loaded. This option tells the compiler that such misaligned accesses will cause a MMU trap and that it should instead -synthesise the access as a series of byte accesses. The compiler can +synthesize the access as a series of byte accesses. The compiler can still use word accesses to load half-word data if it knows that the address is aligned to a word boundary. @@ -5838,25 +6101,6 @@ These are deprecated aliases for @option{-malignment-traps}. @opindex mshort-load-words This are deprecated aliases for @option{-mno-alignment-traps}. -@item -mbsd -@opindex mbsd -This option only applies to RISC iX@. Emulate the native BSD-mode -compiler. This is the default if @option{-ansi} is not specified. - -@item -mxopen -@opindex mxopen -This option only applies to RISC iX@. Emulate the native X/Open-mode -compiler. - -@item -mno-symrename -@opindex mno-symrename -This option only applies to RISC iX@. Do not run the assembler -post-processor, @samp{symrename}, after code has been assembled. -Normally it is necessary to modify some of the standard symbols in -preparation for linking with the RISC iX C library; this option -suppresses this pass. The post-processor is never run when the -compiler is built for cross-compilation. - @item -mcpu=@var{name} @opindex mcpu This specifies the name of the target ARM processor. GCC uses this name @@ -6021,6 +6265,7 @@ of executing a function pointer if this option is enabled. @node MN10200 Options @subsection MN10200 Options @cindex MN10200 options + These @option{-m} options are defined for Matsushita MN10200 architectures: @table @gcctabopt @@ -6036,6 +6281,7 @@ This option makes symbolic debugging impossible. @node MN10300 Options @subsection MN10300 Options @cindex MN10300 options + These @option{-m} options are defined for Matsushita MN10300 architectures: @table @gcctabopt @@ -6198,9 +6444,9 @@ underscore as prefix on each name. Include (or omit) additional debugging information (about registers used in each stack frame) as specified in the 88open Object Compatibility Standard, ``OCS''@. This extra information allows debugging of code that -has had the frame pointer eliminated. The default for DG/UX, SVr4, and -Delta 88 SVr3.2 is to include this information; other 88k configurations -omit this information by default. +has had the frame pointer eliminated. The default for SVr4 and Delta 88 +SVr3.2 is to include this information; other 88k configurations omit this +information by default. @item -mocs-frame-position @opindex mocs-frame-position @@ -6208,7 +6454,7 @@ omit this information by default. When emitting COFF debugging information for automatic variables and parameters stored on the stack, use the offset from the canonical frame address, which is the stack pointer (register 31) on entry to the -function. The DG/UX, SVr4, Delta88 SVr3.2, and BCS configurations use +function. The SVr4 and Delta88 SVr3.2, and BCS configurations use @option{-mocs-frame-position}; other 88k configurations have the default @option{-mno-ocs-frame-position}. @@ -6295,9 +6541,8 @@ that is used on System V release 4. SVr4. @end enumerate -@option{-msvr4} is the default for the m88k-motorola-sysv4 and -m88k-dg-dgux m88k configurations. @option{-msvr3} is the default for all -other m88k configurations. +@option{-msvr4} is the default for the m88k-motorola-sysv4 configuration. +@option{-msvr3} is the default for all other m88k configurations. @item -mversion-03.00 @opindex mversion-03.00 @@ -6503,7 +6748,7 @@ The @option{-mcpu} options automatically enable or disable other @table @samp @item common -@option{-mno-power}, @option{-mno-powerc} +@option{-mno-power}, @option{-mno-powerpc} @item power @itemx power2 @@ -6555,6 +6800,21 @@ allow access to the AltiVec instruction set. You may also need to set @option{-mabi=altivec} to adjust the current ABI with AltiVec ABI enhancements. +@item -mabi=spe +@opindex mabi=spe +Extend the current ABI with SPE ABI extensions. This does not change +the default ABI, instead it adds the SPE ABI extensions to the current +ABI@. + +@item -mabi=no-spe +@opindex mabi=no-spe +Disable Booke SPE ABI extensions for the current ABI. + +@item -misel=@var{yes/no} +@itemx -misel +@opindex misel +This switch enables or disables the generation of ISEL instructions. + @item -mfull-toc @itemx -mno-fp-in-toc @itemx -mno-sum-in-toc @@ -6844,6 +7104,10 @@ On embedded PowerPC systems, assume that the startup module is called On System V.4 and embedded PowerPC systems, specify that you are compiling for a VxWorks system. +@item -mwindiss +@opindex mwindiss +Specify that you are compiling for the WindISS simulation environment. + @item -memb @opindex memb On embedded PowerPC systems, set the @var{PPC_EMB} bit in the ELF flags @@ -6928,6 +7192,24 @@ All modules should be compiled with the same @option{-G @var{num}} value. On System V.4 and embedded PowerPC systems do (do not) emit register names in the assembly language output using symbolic forms. +@item -mlongcall +@itemx -mno-longcall +@opindex mlongcall +@opindex mno-longcall +Default to making all function calls via pointers, so that functions +which reside further than 64 megabytes (67,108,864 bytes) from the +current location can be called. This setting can be overridden by the +@code{shortcall} function attribute, or by @code{#pragma longcall(0)}. + +Some linkers are capable of detecting out-of-range calls and generating +glue code on the fly. On these systems, long calls are unnecessary and +generate slower code. As of this writing, the AIX linker can do this, +as can the GNU linker for PowerPC/64. It is planned to add this feature +to the GNU linker for 32-bit PowerPC systems as well. + +In the future, we may cause GCC to ignore all longcall specifications +when the linker is known to generate glue. + @item -pthread @opindex pthread Adds support for multithreading with the @dfn{pthreads} library. @@ -6935,6 +7217,157 @@ This option sets flags for both the preprocessor and linker. @end table +@node Darwin Options +@subsection Darwin Options +@cindex Darwin options + +These options are defined for all architectures running the Darwin operating +system. These are useful for compatibility with other Mac OS compilers. + +@table @gcctabopt +@item -all_load +@opindex all_load +Loads all members of static archive libraries. +See man ld(1) for more information. + +@item -arch_errors_fatal +@opindex arch_errors_fatal +Cause the errors having to do with files that have the wrong architecture +to be fatal. + +@item -bind_at_load +@opindex bind_at_load +Causes the output file to be marked such that the dynamic linker will +bind all undefined references when the file is loaded or launched. + +@item -bundle +@opindex bundle +Produce a Mach-o bundle format file. +See man ld(1) for more information. + +@item -bundle_loader @var{executable} +@opindex bundle_loader +This specifies the @var{executable} that will be loading the build +output file being linked. See man ld(1) for more information. + +@item -allowable_client @var{client_name} +@item -arch_only + +@item -client_name +@item -compatibility_version +@item -current_version +@item -dependency-file +@item -dylib_file +@item -dylinker_install_name +@item -dynamic +@item -dynamiclib +@item -exported_symbols_list +@item -filelist +@item -flat_namespace +@item -force_cpusubtype_ALL +@item -force_flat_namespace +@item -headerpad_max_install_names +@item -image_base +@item -init +@item -install_name +@item -keep_private_externs +@item -multi_module +@item -multiply_defined +@item -multiply_defined_unused +@item -noall_load +@item -nomultidefs +@item -noprebind +@item -noseglinkedit +@item -pagezero_size +@item -prebind +@item -prebind_all_twolevel_modules +@item -private_bundle +@item -read_only_relocs +@item -sectalign +@item -sectobjectsymbols +@item -whyload +@item -seg1addr +@item -sectcreate +@item -sectobjectsymbols +@item -sectorder +@item -seg_addr_table +@item -seg_addr_table_filename +@item -seglinkedit +@item -segprot +@item -segs_read_only_addr +@item -segs_read_write_addr +@item -single_module +@item -static +@item -sub_library +@item -sub_umbrella +@item -twolevel_namespace +@item -umbrella +@item -undefined +@item -unexported_symbols_list +@item -weak_reference_mismatches +@item -whatsloaded + +@opindex allowable_client +@opindex arch_only +@opindex client_name +@opindex compatibility_version +@opindex current_version +@opindex dependency-file +@opindex dylib_file +@opindex dylinker_install_name +@opindex dynamic +@opindex dynamiclib +@opindex exported_symbols_list +@opindex filelist +@opindex flat_namespace +@opindex force_cpusubtype_ALL +@opindex force_flat_namespace +@opindex headerpad_max_install_names +@opindex image_base +@opindex init +@opindex install_name +@opindex keep_private_externs +@opindex multi_module +@opindex multiply_defined +@opindex multiply_defined_unused +@opindex noall_load +@opindex nomultidefs +@opindex noprebind +@opindex noseglinkedit +@opindex pagezero_size +@opindex prebind +@opindex prebind_all_twolevel_modules +@opindex private_bundle +@opindex read_only_relocs +@opindex sectalign +@opindex sectobjectsymbols +@opindex whyload +@opindex seg1addr +@opindex sectcreate +@opindex sectobjectsymbols +@opindex sectorder +@opindex seg_addr_table +@opindex seg_addr_table_filename +@opindex seglinkedit +@opindex segprot +@opindex segs_read_only_addr +@opindex segs_read_write_addr +@opindex single_module +@opindex static +@opindex sub_library +@opindex sub_umbrella +@opindex twolevel_namespace +@opindex umbrella +@opindex undefined +@opindex unexported_symbols_list +@opindex weak_reference_mismatches +@opindex whatsloaded + +This options are available for Darwin linker. Darwin linker man page +describes them in detail. +@end table + + @node RT Options @subsection IBM RT Options @cindex RT options @@ -6963,14 +7396,13 @@ Do not include extra scratch space in floating point data blocks. This results in smaller code, but slower execution, since scratch space must be allocated dynamically. -@cindex @file{varargs.h} and RT PC @cindex @file{stdarg.h} and RT PC @item -mfp-arg-in-fpregs @opindex mfp-arg-in-fpregs Use a calling sequence incompatible with the IBM calling convention in which floating point arguments are passed in floating point registers. -Note that @code{varargs.h} and @code{stdarg.h} will not work with -floating point operands if this option is specified. +Note that @code{stdarg.h} will not work with floating point operands +if this option is specified. @item -mfp-arg-in-gregs @opindex mfp-arg-in-gregs @@ -7000,65 +7432,77 @@ These @samp{-m} options are defined for the MIPS family of computers: @table @gcctabopt -@item -march=@var{cpu-type} +@item -march=@var{arch} @opindex march -Assume the defaults for the machine type @var{cpu-type} when generating -instructions. The choices for @var{cpu-type} are @samp{r2000}, @samp{r3000}, -@samp{r3900}, @samp{r4000}, @samp{r4100}, @samp{r4300}, @samp{r4400}, -@samp{r4600}, @samp{r4650}, @samp{r5000}, @samp{r6000}, @samp{r8000}, -and @samp{orion}. Additionally, the @samp{r2000}, @samp{r3000}, -@samp{r4000}, @samp{r5000}, and @samp{r6000} can be abbreviated as -@samp{r2k} (or @samp{r2K}), @samp{r3k}, etc. - -@item -mtune=@var{cpu-type} +Generate code that will run on @var{arch}, which can be the name of a +generic MIPS ISA, or the name of a particular processor. The ISA names +are: @samp{mips1}, @samp{mips2}, @samp{mips3}, @samp{mips4}, @samp{mips32} +and @samp{mips64}. The processor names are: @samp{r2000}, +@samp{r3000}, @samp{r3900}, @samp{r4000}, @samp{vr4100}, @samp{vr4300}, +@samp{r4400}, @samp{r4600}, @samp{r4650}, @samp{vr5000}, @samp{r6000}, +@samp{r8000}, @samp{4kc}, @samp{4kp}, @samp{5kc}, @samp{20kc}, +@samp{orion}, and @samp{sb1}. The special value @samp{from-abi} selects the +most compatible architecture for the selected ABI (that is, +@samp{mips1} for 32-bit ABIs and @samp{mips3} for 64-bit ABIs)@. + +In processor names, a final @samp{000} can be abbreviated as @samp{k} +(for example, @samp{-march=r2k}). Prefixes are optional, and +@samp{vr} may be written @samp{r}. + +GCC defines two macros based on the value of this option. The first +is @samp{_MIPS_ARCH}, which gives the name of target architecture, as +a string. The second has the form @samp{_MIPS_ARCH_@var{foo}}, +where @var{foo} is the capitalized value of @samp{_MIPS_ARCH}@. +For example, @samp{-march=r2000} will set @samp{_MIPS_ARCH} +to @samp{"r2000"} and define the macro @samp{_MIPS_ARCH_R2000}. + +Note that the @samp{_MIPS_ARCH} macro uses the processor names given +above. In other words, it will have the full prefix and will not +abbreviate @samp{000} as @samp{k}. In the case of @samp{from-abi}, +the macro names the resolved architecture (either @samp{"mips1"} or +@samp{"mips3"}). It names the default architecture when no +@option{-march} option is given. + +@item -mtune=@var{arch} @opindex mtune -Assume the defaults for the machine type @var{cpu-type} when scheduling -instructions. The choices for @var{cpu-type} are @samp{r2000}, @samp{r3000}, -@samp{r3900}, @samp{r4000}, @samp{r4100}, @samp{r4300}, @samp{r4400}, -@samp{r4600}, @samp{r4650}, @samp{r5000}, @samp{r6000}, @samp{r8000}, -and @samp{orion}. Additionally, the @samp{r2000}, @samp{r3000}, -@samp{r4000}, @samp{r5000}, and @samp{r6000} can be abbreviated as -@samp{r2k} (or @samp{r2K}), @samp{r3k}, etc. While picking a specific -@var{cpu-type} will schedule things appropriately for that particular -chip, the compiler will not generate any code that does not meet level 1 -of the MIPS ISA (instruction set architecture) without a @option{-mipsX} -or @option{-mabi} switch being used. +Optimize for @var{arch}. Among other things, this option controls +the way instructions are scheduled, and the perceived cost of arithmetic +operations. The list of @var{arch} values is the same as for +@option{-march}. -@item -mcpu=@var{cpu-type} -@opindex mcpu -This is identical to specifying both @option{-march} and @option{-mtune}. +When this option is not used, GCC will optimize for the processor +specified by @option{-march}. By using @option{-march} and +@option{-mtune} together, it is possible to generate code that will +run on a family of processors, but optimize the code for one +particular member of that family. + +@samp{-mtune} defines the macros @samp{_MIPS_TUNE} and +@samp{_MIPS_TUNE_@var{foo}}, which work in the same way as the +@samp{-march} ones described above. @item -mips1 @opindex mips1 -Issue instructions from level 1 of the MIPS ISA@. This is the default. -@samp{r3000} is the default @var{cpu-type} at this ISA level. +Equivalent to @samp{-march=mips1}. @item -mips2 @opindex mips2 -Issue instructions from level 2 of the MIPS ISA (branch likely, square -root instructions). @samp{r6000} is the default @var{cpu-type} at this -ISA level. +Equivalent to @samp{-march=mips2}. @item -mips3 @opindex mips3 -Issue instructions from level 3 of the MIPS ISA (64-bit instructions). -@samp{r4000} is the default @var{cpu-type} at this ISA level. +Equivalent to @samp{-march=mips3}. @item -mips4 @opindex mips4 -Issue instructions from level 4 of the MIPS ISA (conditional move, -prefetch, enhanced FPU instructions). @samp{r8000} is the default -@var{cpu-type} at this ISA level. +Equivalent to @samp{-march=mips4}. -@item -mfp32 -@opindex mfp32 -Assume that 32 32-bit floating point registers are available. This is -the default. +@item -mips32 +@opindex mips32 +Equivalent to @samp{-march=mips32}. -@item -mfp64 -@opindex mfp64 -Assume that 32 64-bit floating point registers are available. This is -the default when the @option{-mips3} option is used. +@item -mips64 +@opindex mips64 +Equivalent to @samp{-march=mips64}. @item -mfused-madd @itemx -mno-fused-madd @@ -7072,15 +7516,21 @@ in the mode where denormals are rounded to zero where denormals generated by multiply and accumulate instructions cause exceptions anyway. +@item -mfp32 +@opindex mfp32 +Assume that floating point registers are 32 bits wide. + +@item -mfp64 +@opindex mfp64 +Assume that floating point registers are 64 bits wide. + @item -mgp32 @opindex mgp32 -Assume that 32 32-bit general purpose registers are available. This is -the default. +Assume that general purpose registers are 32 bits wide. @item -mgp64 @opindex mgp64 -Assume that 32 64-bit general purpose registers are available. This is -the default when the @option{-mips3} option is used. +Assume that general purpose registers are 64 bits wide. @item -mint64 @opindex mint64 @@ -7096,31 +7546,32 @@ explanation of the default, and the width of pointers. @opindex mlong32 Force long, int, and pointer types to be 32 bits wide. -If none of @option{-mlong32}, @option{-mlong64}, or @option{-mint64} are set, -the size of ints, longs, and pointers depends on the ABI and ISA chosen. -For @option{-mabi=32}, and @option{-mabi=n32}, ints and longs are 32 bits -wide. For @option{-mabi=64}, ints are 32 bits, and longs are 64 bits wide. -For @option{-mabi=eabi} and either @option{-mips1} or @option{-mips2}, ints -and longs are 32 bits wide. For @option{-mabi=eabi} and higher ISAs, ints -are 32 bits, and longs are 64 bits wide. The width of pointer types is -the smaller of the width of longs or the width of general purpose -registers (which in turn depends on the ISA)@. +The default size of ints, longs and pointers depends on the ABI@. All +the supported ABIs use 32-bit ints. The n64 ABI uses 64-bit longs, as +does the 64-bit Cygnus EABI; the others use 32-bit longs. Pointers +are the same size as longs, or the same size as integer registers, +whichever is smaller. @item -mabi=32 @itemx -mabi=o64 @itemx -mabi=n32 @itemx -mabi=64 @itemx -mabi=eabi +@itemx -mabi=meabi @opindex mabi=32 @opindex mabi=o64 @opindex mabi=n32 @opindex mabi=64 @opindex mabi=eabi -Generate code for the indicated ABI@. The default instruction level is -@option{-mips1} for @samp{32}, @option{-mips3} for @samp{n32}, and -@option{-mips4} otherwise. Conversely, with @option{-mips1} or -@option{-mips2}, the default ABI is @samp{32}; otherwise, the default ABI -is @samp{64}. +@opindex mabi=meabi +Generate code for the given ABI@. + +Note that there are two embedded ABIs: @option{-mabi=eabi} +selects the one defined by Cygnus while @option{-meabi=meabi} +selects the one defined by MIPS@. Both these ABIs have +32-bit and 64-bit variants. Normally, GCC will generate +64-bit code when you select a 64-bit architecture, but you +can use @option{-mgp32} to get 32-bit code instead. @item -mmips-as @opindex mmips-as @@ -7343,12 +7794,19 @@ memory range for which the cache is being flushed, the size of the memory range, and the number 3 (to flush both caches). The default depends on the target gcc was configured for, but commonly is either @samp{_flush_func} or @samp{__cpu_flush}. -@end table -These options are defined by the macro -@code{TARGET_SWITCHES} in the machine description. The default for the -options is also defined by that macro, which enables you to change the -defaults. +@item -mbranch-likely +@itemx -mno-branch-likely +@opindex mbranch-likely +@opindex mno-branch-likely +Enable or disable use of Branch Likely instructions, regardless of the +default for the selected architecture. By default, Branch Likely +instructions may be generated if they are supported by the selected +architecture. An exception is for the MIPS32 and MIPS64 architectures +and processors which implement those architectures; for those, Branch +Likely instructions will not be generated by default because the MIPS32 +and MIPS64 architectures specifically deprecate their use. +@end table @node i386 and x86-64 Options @subsection Intel 386 and AMD x86-64 Options @@ -7368,8 +7826,8 @@ for the ABI and the set of available instructions. The choices for @var{cpu-type} are @samp{i386}, @samp{i486}, @samp{i586}, @samp{i686}, @samp{pentium}, @samp{pentium-mmx}, @samp{pentiumpro}, @samp{pentium2}, @samp{pentium3}, @samp{pentium4}, @samp{k6}, @samp{k6-2}, @samp{k6-3}, -@samp{athlon}, @samp{athlon-tbird}, @samp{athlon-4}, @samp{athlon-xp} -and @samp{athlon-mp}. +@samp{athlon}, @samp{athlon-tbird}, @samp{athlon-4}, @samp{athlon-xp}, +@samp{athlon-mp}, @samp{winchip-c6}, @samp{winchip2} and @samp{c3}. While picking a specific @var{cpu-type} will schedule things appropriately for that particular chip, the compiler will not generate any code that @@ -7405,7 +7863,7 @@ for @var{unit} are: @item 387 Use the standard 387 floating point coprocessor present majority of chips and emulated otherwise. Code compiled with this option will run almost everywhere. -The temporary results are computed in 80bit precesion instead of precision +The temporary results are computed in 80bit precision instead of precision specified by the type resulting in slightly different results compared to most of other chips. See @option{-ffloat-store} for more detailed description. @@ -7431,7 +7889,7 @@ code that expects temporaries to be 80bit. This is the default choice for x86-64 compiler. @item sse,387 -Attempt to utilize both instruction sets at once. This effectivly double the +Attempt to utilize both instruction sets at once. This effectively double the amount of available registers and on chips with separate execution units for 387 and SSE the execution resources too. Use this option with care, as it is still experimental, because gcc register allocator does not model separate @@ -7614,8 +8072,8 @@ direct access to the MMX, SSE and 3Dnow extensions of the instruction set. @xref{X86 Built-in Functions}, for details of the functions enabled and disabled by these switches. -To have SSE/SSE2 instructions generated automatically from floating-point code, -see @option{-mfpmath=sse}. +To have SSE/SSE2 instructions generated automatically from floating-point +code, see @option{-mfpmath=sse}. @item -mpush-args @itemx -mno-push-args @@ -7799,15 +8257,16 @@ Enable the use of assembler directives only GAS understands. @opindex mschedule Schedule code according to the constraints for the machine type @var{cpu-type}. The choices for @var{cpu-type} are @samp{700} -@samp{7100}, @samp{7100LC}, @samp{7200}, and @samp{8000}. Refer to -@file{/usr/lib/sched.models} on an HP-UX system to determine the -proper scheduling option for your machine. +@samp{7100}, @samp{7100LC}, @samp{7200}, @samp{7300} and @samp{8000}. Refer +to @file{/usr/lib/sched.models} on an HP-UX system to determine the +proper scheduling option for your machine. The default scheduling is +@samp{8000}. @item -mlinker-opt @opindex mlinker-opt -Enable the optimization pass in the HPUX linker. Note this makes symbolic -debugging impossible. It also triggers a bug in the HPUX 8 and HPUX 9 linkers -in which they give bogus error messages when linking some programs. +Enable the optimization pass in the HP-UX linker. Note this makes symbolic +debugging impossible. It also triggers a bug in the HP-UX 8 and HP-UX 9 +linkers in which they give bogus error messages when linking some programs. @item -msoft-float @opindex msoft-float @@ -7824,6 +8283,88 @@ therefore, it is only useful if you compile @emph{all} of a program with this option. In particular, you need to compile @file{libgcc.a}, the library that comes with GCC, with @option{-msoft-float} in order for this to work. + +@item -msio +@opindex msio +Generate the predefine, @code{_SIO}, for server IO. The default is +@option{-mwsio}. This generates the predefines, @code{__hp9000s700}, +@code{__hp9000s700__} and @code{_WSIO}, for workstation IO. These +options are available under HP-UX and HI-UX. + +@item -mgnu-ld +@opindex gnu-ld +Use GNU ld specific options. This passes @option{-shared} to ld when +building a shared library. It is the default when GCC is configured, +explicitly or implicitly, with the GNU linker. This option does not +have any affect on which ld is called, it only changes what parameters +are passed to that ld. The ld that is called is determined by the +@option{--with-ld} configure option, gcc's program search path, and +finally by the user's @env{PATH}. The linker used by GCC can be printed +using @samp{which `gcc -print-prog-name=ld`}. + +@item -mhp-ld +@opindex hp-ld +Use HP ld specific options. This passes @option{-b} to ld when building +a shared library and passes @option{+Accept TypeMismatch} to ld on all +links. It is the default when GCC is configured, explicitly or +implicitly, with the HP linker. This option does not have any affect on +which ld is called, it only changes what parameters are passed to that +ld. The ld that is called is determined by the @option{--with-ld} +configure option, gcc's program search path, and finally by the user's +@env{PATH}. The linker used by GCC can be printed using @samp{which +`gcc -print-prog-name=ld`}. + +@item -mlong-calls +@opindex mno-long-calls +Generate code that uses long call sequences. This ensures that a call +is always able to reach linker generated stubs. The default is to generate +long calls only when the distance from the call site to the beginning +of the function or translation unit, as the case may be, exceeds a +predefined limit set by the branch type being used. The limits for +normal calls are 7,600,000 and 240,000 bytes, respectively for the +PA 2.0 and PA 1.X architectures. Sibcalls are always limited at +240,000 bytes. + +Distances are measured from the beginning of functions when using the +@option{-ffunction-sections} option, or when using the @option{-mgas} +and @option{-mno-portable-runtime} options together under HP-UX with +the SOM linker. + +It is normally not desirable to use this option as it will degrade +performance. However, it may be useful in large applications, +particularly when partial linking is used to build the application. + +The types of long calls used depends on the capabilities of the +assembler and linker, and the type of code being generated. The +impact on systems that support long absolute calls, and long pic +symbol-difference or pc-relative calls should be relatively small. +However, an indirect call is used on 32-bit ELF systems in pic code +and it is quite long. + +@item -nolibdld +@opindex nolibdld +Suppress the generation of link options to search libdld.sl when the +@option{-static} option is specified on HP-UX 10 and later. + +@item -static +@opindex static +The HP-UX implementation of setlocale in libc has a dependency on +libdld.sl. There isn't an archive version of libdld.sl. Thus, +when the @option{-static} option is specified, special link options +are needed to resolve this dependency. + +On HP-UX 10 and later, the GCC driver adds the necessary options to +link with libdld.sl when the @option{-static} option is specified. +This causes the resulting binary to be dynamic. On the 64-bit port, +the linkers generate dynamic binaries by default in any case. The +@option{-nolibdld} option can be used to prevent the GCC driver from +adding these link options. + +@item -threads +@opindex threads +Add support for multithreading with the @dfn{dce thread} library +under HP-UX. This option sets flags for both the preprocessor and +linker. @end table @node Intel 960 Options @@ -8143,7 +8684,7 @@ arithmetic instead of IEEE single and double precision. @opindex mno-explicit-relocs Older Alpha assemblers provided no way to generate symbol relocations except via assembler macros. Use of these macros does not allow -optimial instruction scheduling. GNU binutils as of version 2.12 +optimal instruction scheduling. GNU binutils as of version 2.12 supports a new syntax that allows the compiler to explicitly mark which relocations should apply to which instructions. This option is mostly useful for debugging, as GCC detects the capabilities of @@ -8251,22 +8792,6 @@ Return VMS condition codes from main. The default is to return POSIX style condition (e.g.@ error) codes. @end table -@node Clipper Options -@subsection Clipper Options - -These @samp{-m} options are defined for the Clipper implementations: - -@table @gcctabopt -@item -mc300 -@opindex mc300 -Produce code for a C300 Clipper processor. This is the default. - -@item -mc400 -@opindex mc400 -Produce code for a C400 Clipper processor, i.e.@: use floating point -registers f8--f15. -@end table - @node H8/300 Options @subsection H8/300 Options @@ -8285,11 +8810,16 @@ Generate code for the H8/300H@. @item -ms @opindex ms -Generate code for the H8/S@. +Generate code for the H8S@. + +@item -mn +@opindex mn +Generate code for the H8S and H8/300H in the normal mode. This switch +must be used either with -mh or -ms. @item -ms2600 @opindex ms2600 -Generate code for the H8/S2600. This switch must be used with @option{-ms}. +Generate code for the H8S/2600. This switch must be used with @option{-ms}. @item -mint32 @opindex mint32 @@ -8297,8 +8827,8 @@ Make @code{int} data 32 bits by default. @item -malign-300 @opindex malign-300 -On the H8/300H and H8/S, use the same alignment rules as for the H8/300. -The default for the H8/300H and H8/S is to align longs and floats on 4 +On the H8/300H and H8S, use the same alignment rules as for the H8/300. +The default for the H8/300H and H8S is to align longs and floats on 4 byte boundaries. @option{-malign-300} causes them to be aligned on 2 byte boundaries. This option has no effect on the H8/300. @@ -8374,7 +8904,7 @@ Enable the use of the instruction @code{fmovd}. @item -mhitachi @opindex mhitachi -Comply with the calling conventions defined by Hitachi. +Comply with the calling conventions defined by Renesas. @item -mnomacsave @opindex mnomacsave @@ -8493,10 +9023,10 @@ DBcond(D), instructions. This is enabled by default for the C4x. To be on the safe side, this is disabled for the C3x, since the maximum iteration count on the C3x is @math{2^{23} + 1} (but who iterates loops more than @math{2^{23}} times on the C3x?). Note that GCC will try to reverse a loop so -that it can utilise the decrement and branch instruction, but will give +that it can utilize the decrement and branch instruction, but will give up if there is more than one memory reference in the loop. Thus a loop where the loop counter is decremented can generate slightly more -efficient code, in cases where the RPTB instruction cannot be utilised. +efficient code, in cases where the RPTB instruction cannot be utilized. @item -mdp-isr-reload @itemx -mparanoid @@ -8663,6 +9193,34 @@ Specify that the target processor is the V850. Generate code suitable for big switch tables. Use this option only if the assembler/linker complain about out of range branches within a switch table. + +@item -mapp-regs +@opindex mapp-regs +This option will cause r2 and r5 to be used in the code generated by +the compiler. This setting is the default. + +@item -mno-app-regs +@opindex mno-app-regs +This option will cause r2 and r5 to be treated as fixed registers. + +@item -mv850e +@opindex mv850e +Specify that the target processor is the V850E. The preprocessor +constant @samp{__v850e__} will be defined if this option is used. + +If neither @option{-mv850} nor @option{-mv850e} are defined +then a default target processor will be chosen and the relevant +@samp{__v850*__} preprocessor constant will be defined. + +The preprocessor constants @samp{__v850} and @samp{__v851__} are always +defined, regardless of which processor variant is the target. + +@item -mdisable-callt +@opindex mdisable-callt +This option will suppress generation of the CALLT instruction for the +v850e flavors of the v850 architecture. The default is +@option{-mno-disable-callt} which allows the CALLT instruction to be used. + @end table @node ARC Options @@ -8769,6 +9327,15 @@ Do not try and generate multiply-add floating point instructions Generate output containing library calls for floating point. @strong{Warning:} the requisite libraries may not be available. +@item -mieee-compare +@itemx -mno-ieee-compare +@opindex mieee-compare +@opindex mno-ieee-compare +Control whether or not the compiler uses IEEE floating point +comparisons. These handle correctly the case where the result of a +comparison is unordered. +@strong{Warning:} the requisite kernel support may not be available. + @item -mnobitfield @opindex mnobitfield Do not use the bit-field instructions. On some machines it is faster to @@ -8910,75 +9477,57 @@ processors. @table @gcctabopt @item -mhardlit -@itemx -mhardlit @itemx -mno-hardlit @opindex mhardlit -@opindex mhardlit @opindex mno-hardlit Inline constants into the code stream if it can be done in two instructions or less. @item -mdiv -@itemx -mdiv @itemx -mno-div @opindex mdiv -@opindex mdiv @opindex mno-div Use the divide instruction. (Enabled by default). @item -mrelax-immediate -@itemx -mrelax-immediate @itemx -mno-relax-immediate @opindex mrelax-immediate -@opindex mrelax-immediate @opindex mno-relax-immediate Allow arbitrary sized immediates in bit operations. @item -mwide-bitfields -@itemx -mwide-bitfields @itemx -mno-wide-bitfields @opindex mwide-bitfields -@opindex mwide-bitfields @opindex mno-wide-bitfields Always treat bit-fields as int-sized. @item -m4byte-functions -@itemx -m4byte-functions @itemx -mno-4byte-functions @opindex m4byte-functions -@opindex m4byte-functions @opindex mno-4byte-functions Force all functions to be aligned to a four byte boundary. @item -mcallgraph-data -@itemx -mcallgraph-data @itemx -mno-callgraph-data @opindex mcallgraph-data -@opindex mcallgraph-data @opindex mno-callgraph-data Emit callgraph information. @item -mslow-bytes -@itemx -mslow-bytes @itemx -mno-slow-bytes @opindex mslow-bytes -@opindex mslow-bytes @opindex mno-slow-bytes Prefer word access when reading byte quantities. @item -mlittle-endian -@itemx -mlittle-endian @itemx -mbig-endian @opindex mlittle-endian -@opindex mlittle-endian @opindex mbig-endian Generate code for a little endian target. @item -m210 -@itemx -m210 @itemx -m340 @opindex m210 -@opindex m210 @opindex m340 Generate code for the 210 processor. @end table @@ -8992,7 +9541,7 @@ These are the @samp{-m} options defined for the Intel IA-64 architecture. @table @gcctabopt @item -mbig-endian @opindex mbig-endian -Generate code for a big endian target. This is the default for HPUX@. +Generate code for a big endian target. This is the default for HP-UX@. @item -mlittle-endian @opindex mlittle-endian @@ -9055,13 +9604,25 @@ useful when compiling kernel code. Generate code that is self-relocatable. This implies @option{-mconstant-gp}. This is useful when compiling firmware code. -@item -minline-divide-min-latency -@opindex minline-divide-min-latency -Generate code for inline divides using the minimum latency algorithm. +@item -minline-float-divide-min-latency +@opindex minline-float-divide-min-latency +Generate code for inline divides of floating point values +using the minimum latency algorithm. + +@item -minline-float-divide-max-throughput +@opindex minline-float-divide-max-throughput +Generate code for inline divides of floating point values +using the maximum throughput algorithm. -@item -minline-divide-max-throughput -@opindex minline-divide-max-throughput -Generate code for inline divides using the maximum throughput algorithm. +@item -minline-int-divide-min-latency +@opindex minline-int-divide-min-latency +Generate code for inline divides of integer values +using the minimum latency algorithm. + +@item -minline-int-divide-max-throughput +@opindex minline-int-divide-max-throughput +Generate code for inline divides of integer values +using the maximum throughput algorithm. @item -mno-dwarf2-asm @itemx -mdwarf2-asm @@ -9175,7 +9736,7 @@ targets default to @option{-m64}. @opindex mmvcle @opindex mno-mvcle Generate (or do not generate) code using the @code{mvcle} instruction -to perform block moves. When @option{-mno-mvcle} is specifed, +to perform block moves. When @option{-mno-mvcle} is specified, use a @code{mvc} loop instead. This is the default. @item -mdebug @@ -9401,6 +9962,13 @@ to 255 from the value held in the register. The generally leads to short and fast code, but the number of different data items that can be addressed is limited. This means that a program that uses lots of static data may require @option{-mno-base-addresses}. + +@item -msingle-exit +@itemx -mno-single-exit +@opindex msingle-exit +@opindex mno-single-exit +Force (do not force) generated code to have a single exit point in each +function. @end table @node PDP-11 Options @@ -9520,6 +10088,233 @@ These options are defined for Xstormy16: Choose startup files and linker script suitable for the simulator. @end table +@node FRV Options +@subsection FRV Options +@cindex FRV Options + +@table @gcctabopt +@item -mgpr-32 +@opindex mgpr-32 + +Only use the first 32 general purpose registers. + +@item -mgpr-64 +@opindex mgpr-64 + +Use all 64 general purpose registers. + +@item -mfpr-32 +@opindex mfpr-32 + +Use only the first 32 floating point registers. + +@item -mfpr-64 +@opindex mfpr-64 + +Use all 64 floating point registers + +@item -mhard-float +@opindex mhard-float + +Use hardware instructions for floating point operations. + +@item -msoft-float +@opindex msoft-float + +Use library routines for floating point operations. + +@item -malloc-cc +@opindex malloc-cc + +Dynamically allocate condition code registers. + +@item -mfixed-cc +@opindex mfixed-cc + +Do not try to dynamically allocate condition code registers, only +use @code{icc0} and @code{fcc0}. + +@item -mdword +@opindex mdword + +Change ABI to use double word insns. + +@item -mno-dword +@opindex mno-dword + +Do not use double word instructions. + +@item -mdouble +@opindex mdouble + +Use floating point double instructions. + +@item -mno-double +@opindex mno-double + +Do not use floating point double instructions. + +@item -mmedia +@opindex mmedia + +Use media instructions. + +@item -mno-media +@opindex mno-media + +Do not use media instructions. + +@item -mmuladd +@opindex mmuladd + +Use multiply and add/subtract instructions. + +@item -mno-muladd +@opindex mno-muladd + +Do not use multiply and add/subtract instructions. + +@item -mlibrary-pic +@opindex mlibrary-pic + +Enable PIC support for building libraries + +@item -macc-4 +@opindex macc-4 + +Use only the first four media accumulator registers. + +@item -macc-8 +@opindex macc-8 + +Use all eight media accumulator registers. + +@item -mpack +@opindex mpack + +Pack VLIW instructions. + +@item -mno-pack +@opindex mno-pack + +Do not pack VLIW instructions. + +@item -mno-eflags +@opindex mno-eflags + +Do not mark ABI switches in e_flags. + +@item -mcond-move +@opindex mcond-move + +Enable the use of conditional-move instructions (default). + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mno-cond-move +@opindex mno-cond-move + +Disable the use of conditional-move instructions. + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mscc +@opindex mscc + +Enable the use of conditional set instructions (default). + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mno-scc +@opindex mno-scc + +Disable the use of conditional set instructions. + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mcond-exec +@opindex mcond-exec + +Enable the use of conditional execution (default). + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mno-cond-exec +@opindex mno-cond-exec + +Disable the use of conditional execution. + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mvliw-branch +@opindex mvliw-branch + +Run a pass to pack branches into VLIW instructions (default). + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mno-vliw-branch +@opindex mno-vliw-branch + +Do not run a pass to pack branches into VLIW instructions. + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mmulti-cond-exec +@opindex mmulti-cond-exec + +Enable optimization of @code{&&} and @code{||} in conditional execution +(default). + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mno-multi-cond-exec +@opindex mno-multi-cond-exec + +Disable optimization of @code{&&} and @code{||} in conditional execution. + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mnested-cond-exec +@opindex mnested-cond-exec + +Enable nested conditional execution optimizations (default). + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mno-nested-cond-exec +@opindex mno-nested-cond-exec + +Disable nested conditional execution optimizations. + +This switch is mainly for debugging the compiler and will likely be removed +in a future version. + +@item -mtomcat-stats +@opindex mtomcat-stats + +Cause gas to print out tomcat statistics. + +@item -mcpu=@var{cpu} +@opindex mcpu + +Select the processor type for which to generate code. Possible values are +@samp{simple}, @samp{tomcat}, @samp{fr500}, @samp{fr400}, @samp{fr300}, +@samp{frv}. + +@end table + @node Xtensa Options @subsection Xtensa Options @cindex Xtensa Options @@ -9709,6 +10504,18 @@ can figure out the other form by either removing @samp{no-} or adding it. @table @gcctabopt +@item -fbounds-check +@opindex fbounds-check +For front-ends that support it, generate additional code to check that +indices used to access arrays are within the declared range. This is +currently only supported by the Java and Fortran 77 front-ends, where +this option defaults to true and false respectively. + +@item -ftrapv +@opindex ftrapv +This option generates traps for signed overflow on addition, subtraction, +multiplication operations. + @item -fexceptions @opindex fexceptions Enable exception handling. Generates extra code needed to propagate @@ -9887,7 +10694,7 @@ loader is not part of GCC; it is part of the operating system). If the GOT size for the linked executable exceeds a machine-specific maximum size, you get an error message from the linker indicating that @option{-fpic} does not work; in that case, recompile with @option{-fPIC} -instead. (These maximums are 16k on the m88k, 8k on the Sparc, and 32k +instead. (These maximums are 16k on the m88k, 8k on the SPARC, and 32k on the m68k and RS/6000. The 386 has no such limit.) Position-independent code requires special support, and therefore works @@ -9900,7 +10707,7 @@ position-independent. If supported for the target machine, emit position-independent code, suitable for dynamic linking and avoiding any limit on the size of the global offset table. This option makes a difference on the m68k, m88k, -and the Sparc. +and the SPARC. Position-independent code requires special support, and therefore works only on certain machines. @@ -9955,7 +10762,7 @@ Pack all structure members together without holes. @strong{Warning:} the @option{-fpack-struct} switch causes GCC to generate code that is not binary compatible with code generated without that switch. -Additionally, it makes the code suboptimial. +Additionally, it makes the code suboptimal. Use it to conform to a non-default application binary interface. @item -finstrument-functions @@ -10057,6 +10864,14 @@ is to help link with legacy assembly code. generate code that is not binary compatible with code generated without that switch. Use it to conform to a non-default application binary interface. Not all targets provide complete support for this switch. + +@item -ftls-model=@var{model} +Alter the thread-local storage model to be used (@pxref{Thread-Local}). +The @var{model} argument should be one of @code{global-dynamic}, +@code{local-dynamic}, @code{initial-exec} or @code{local-exec}. + +The default without @option{-fpic} is @code{initial-exec}; with +@option{-fpic} the default is @code{global-dynamic}. @end table @c man end @@ -10066,7 +10881,6 @@ Not all targets provide complete support for this switch. @cindex environment variables @c man begin ENVIRONMENT - This section describes several environment variables that affect how GCC operates. Some of them work by specifying directories or prefixes to use when searching for various kinds of files. Some are used to specify other @@ -10275,16 +11089,16 @@ prototype information about standard system functions. This option applies only to @code{protoize}. @item -c @var{compilation-options} -Use @var{compilation-options} as the options when running @code{gcc} to +Use @var{compilation-options} as the options when running @command{gcc} to produce the @samp{.X} files. The special option @option{-aux-info} is -always passed in addition, to tell @code{gcc} to write a @samp{.X} file. +always passed in addition, to tell @command{gcc} to write a @samp{.X} file. Note that the compilation options must be given as a single argument to @code{protoize} or @code{unprotoize}. If you want to specify several -@code{gcc} options, you must quote the entire set of compilation options +@command{gcc} options, you must quote the entire set of compilation options to make them a single word in the shell. -There are certain @code{gcc} arguments that you cannot use, because they +There are certain @command{gcc} arguments that you cannot use, because they would produce the wrong kind of output. These include @option{-g}, @option{-O}, @option{-c}, @option{-S}, and @option{-o} If you include these in the @var{compilation-options}, they are ignored. @@ -10337,12 +11151,12 @@ Use the program @var{program} as the compiler. Normally, the name Work quietly. Most warnings are suppressed. @item -v -Print the version number, just like @option{-v} for @code{gcc}. +Print the version number, just like @option{-v} for @command{gcc}. @end table If you need special compiler options to compile one of your program's source files, then you should generate that file's @samp{.X} file -specially, by running @code{gcc} on that source file with the +specially, by running @command{gcc} on that source file with the appropriate options and the option @option{-aux-info}. Then run @code{protoize} on the entire set of files. @code{protoize} will use the existing @samp{.X} file because it is newer than the source file. |
