Define several extra macros in bsd.sys.mk and sys/conf/kern.pre.mk, to

get rid of testing explicitly for clang (using ${CC:T:Mclang}) in
individual Makefiles.

Instead, use the following extra macros, for use with clang:
- NO_WERROR.clang       (disables -Werror)
- NO_WCAST_ALIGN.clang  (disables -Wcast-align)
- NO_WFORMAT.clang	(disables -Wformat and friends)
- CLANG_NO_IAS		(disables integrated assembler)
- CLANG_OPT_SMALL	(adds flags for extra small size optimizations)

As a side effect, this enables setting CC/CXX/CPP in src.conf instead of
make.conf!  For clang, use the following:

CC=clang
CXX=clang++
CPP=clang-cpp

MFC after:	2 weeks

9 files changed, 39 insertions, 51 deletions

diff --git a/sys/boot/i386/boot0/Makefile b/sys/boot/i386/boot0/Makefile
index 4013983..38281a1 100644
--- a/sys/boot/i386/boot0/Makefile
+++ b/sys/boot/i386/boot0/Makefile
@@ -19,12 +19,6 @@ SRCS=	${PROG}.S
 OPTS ?= -DVOLUME_SERIAL -DPXE
 CFLAGS += ${OPTS}
 
-.if ${CC:T:Mclang} == "clang"
-# XXX: clang integrated-as doesn't grok .codeNN directives yet
-CFLAGS+=	${.IMPSRC:T:Mboot0.S:C/^.+$/-no-integrated-as/}
-CFLAGS+=	${.IMPSRC:T:Mboot0ext.S:C/^.+$/-no-integrated-as/}
-.endif
-
 # Flags used in the boot0.S code:
 #   0x0f	all valid partitions enabled.
 #   0x80	'packet', use BIOS EDD (LBA) extensions instead of CHS
@@ -83,3 +77,8 @@ CFLAGS+=-DFLAGS=${BOOT_BOOT0_FLAGS} \
 LDFLAGS=-e start -Ttext ${BOOT_BOOT0_ORG} -Wl,-N,-S,--oformat,binary
 
 .include <bsd.prog.mk>
+
+# XXX: clang integrated-as doesn't grok .codeNN directives yet
+CFLAGS.boot0.S=		${CLANG_NO_IAS}
+CFLAGS.boot0ext.S=	${CLANG_NO_IAS}
+CFLAGS+=		${CFLAGS.${.IMPSRC:T}}
diff --git a/sys/boot/i386/boot2/Makefile b/sys/boot/i386/boot2/Makefile
index e2fc534..68e49ed 100644
--- a/sys/boot/i386/boot2/Makefile
+++ b/sys/boot/i386/boot2/Makefile
@@ -40,14 +40,8 @@ CFLAGS=	-Os \
 	-Wall -Waggregate-return -Wbad-function-cast -Wcast-align \
 	-Wmissing-declarations -Wmissing-prototypes -Wnested-externs \
 	-Wpointer-arith -Wshadow -Wstrict-prototypes -Wwrite-strings \
-	-Winline --param max-inline-insns-single=100
-
-.if ${CC:T:Mclang} == "clang"
-CFLAGS+=	-mllvm -stack-alignment=8 -mllvm -inline-threshold=3 \
-		-mllvm -enable-load-pre=false
-# XXX: clang integrated-as doesn't grok .codeNN directives yet
-CFLAGS+=	${.IMPSRC:T:Mboot1.S:C/^.+$/-no-integrated-as/}
-.endif
+	-Winline --param max-inline-insns-single=100 \
+	${CLANG_OPT_SMALL}
 
 LDFLAGS=-static -N --gc-sections
 
@@ -89,9 +83,7 @@ boot2.out: ${BTXCRT} boot2.o sio.o
 	${LD} ${LDFLAGS} -Ttext ${ORG2} -o ${.TARGET} ${.ALLSRC}
 
 boot2.o: boot2.s
-.if ${CC:T:Mclang} == "clang"
 	${CC} ${ACFLAGS} -c boot2.s
-.endif
 
 SRCS=	boot2.c boot2.h
 
@@ -115,3 +107,7 @@ machine:
 .endif
 
 .include <bsd.prog.mk>
+
+# XXX: clang integrated-as doesn't grok .codeNN directives yet
+CFLAGS.boot1.S=		${CLANG_NO_IAS}
+CFLAGS+=		${CFLAGS.${.IMPSRC:T}}
diff --git a/sys/boot/i386/btx/btx/Makefile b/sys/boot/i386/btx/btx/Makefile
index 4c74c1d..2b4abe6 100644
--- a/sys/boot/i386/btx/btx/Makefile
+++ b/sys/boot/i386/btx/btx/Makefile
@@ -13,11 +13,6 @@ BOOT_BTX_FLAGS=0x0
 
 CFLAGS+=-DBTX_FLAGS=${BOOT_BTX_FLAGS}
 
-.if ${CC:T:Mclang} == "clang"
-# XXX: clang integrated-as doesn't grok .codeNN directives yet
-CFLAGS+=${.IMPSRC:T:Mbtx.S:C/^.+$/-no-integrated-as/}
-.endif
-
 .if defined(BTX_SERIAL)
 BOOT_COMCONSOLE_PORT?= 0x3f8
 BOOT_COMCONSOLE_SPEED?= 9600
@@ -32,3 +27,7 @@ ORG=	0x9000
 LDFLAGS=-e start -Ttext ${ORG} -Wl,-N,-S,--oformat,binary
 
 .include <bsd.prog.mk>
+
+# XXX: clang integrated-as doesn't grok .codeNN directives yet
+CFLAGS.btx.S=		${CLANG_NO_IAS}
+CFLAGS+=		${CFLAGS.${.IMPSRC:T}}
diff --git a/sys/boot/i386/btx/btxldr/Makefile b/sys/boot/i386/btx/btxldr/Makefile
index 0e12f46..56333e7 100644
--- a/sys/boot/i386/btx/btxldr/Makefile
+++ b/sys/boot/i386/btx/btxldr/Makefile
@@ -11,11 +11,10 @@ CFLAGS+=-DLOADER_ADDRESS=${LOADER_ADDRESS}
 CFLAGS+=-DBTXLDR_VERBOSE
 .endif
 
-.if ${CC:T:Mclang} == "clang"
-# XXX: clang integrated-as doesn't grok .codeNN directives yet
-CFLAGS+=${.IMPSRC:T:Mbtxldr.S:C/^.+$/-no-integrated-as/}
-.endif
-
 LDFLAGS=-e start -Ttext ${LOADER_ADDRESS} -Wl,-N,-S,--oformat,binary
 
 .include <bsd.prog.mk>
+
+# XXX: clang integrated-as doesn't grok .codeNN directives yet
+CFLAGS.btxldr.S=	${CLANG_NO_IAS}
+CFLAGS+=		${CFLAGS.${.IMPSRC:T}}
diff --git a/sys/boot/i386/gptboot/Makefile b/sys/boot/i386/gptboot/Makefile
index 48a6d59..e1a640a 100644
--- a/sys/boot/i386/gptboot/Makefile
+++ b/sys/boot/i386/gptboot/Makefile
@@ -36,11 +36,6 @@ CFLAGS=	-DBOOTPROG=\"gptboot\" \
 	-Wpointer-arith -Wshadow -Wstrict-prototypes -Wwrite-strings \
 	-Winline --param max-inline-insns-single=100
 
-.if ${CC:T:Mclang} == "clang"
-# XXX: clang integrated-as doesn't grok .codeNN directives yet
-CFLAGS+=	${.IMPSRC:T:Mgptldr.S:C/^.+$/-no-integrated-as/}
-.endif
-
 LDFLAGS=-static -N --gc-sections
 
 # Pick up ../Makefile.inc early.
@@ -79,3 +74,7 @@ machine:
 .endif
 
 .include <bsd.prog.mk>
+
+# XXX: clang integrated-as doesn't grok .codeNN directives yet
+CFLAGS.gptldr.S=	${CLANG_NO_IAS}
+CFLAGS+=		${CFLAGS.${.IMPSRC:T}}
diff --git a/sys/boot/i386/gptzfsboot/Makefile b/sys/boot/i386/gptzfsboot/Makefile
index 2067162..a2b8fcc 100644
--- a/sys/boot/i386/gptzfsboot/Makefile
+++ b/sys/boot/i386/gptzfsboot/Makefile
@@ -34,11 +34,6 @@ CFLAGS=	-DBOOTPROG=\"gptzfsboot\" \
 	-Wpointer-arith -Wshadow -Wstrict-prototypes -Wwrite-strings \
 	-Winline --param max-inline-insns-single=100
 
-.if ${CC:T:Mclang} == "clang"
-# XXX: clang integrated-as doesn't grok .codeNN directives yet
-CFLAGS+=	${.IMPSRC:T:Mgptldr.S:C/^.+$/-no-integrated-as/}
-.endif
-
 LDFLAGS=-static -N --gc-sections
 
 # Pick up ../Makefile.inc early.
@@ -77,3 +72,7 @@ machine:
 .endif
 
 .include <bsd.prog.mk>
+
+# XXX: clang integrated-as doesn't grok .codeNN directives yet
+CFLAGS.gptldr.S=	${CLANG_NO_IAS}
+CFLAGS+=		${CFLAGS.${.IMPSRC:T}}
diff --git a/sys/boot/i386/libi386/Makefile b/sys/boot/i386/libi386/Makefile
index de32c91..94a20c8 100644
--- a/sys/boot/i386/libi386/Makefile
+++ b/sys/boot/i386/libi386/Makefile
@@ -54,11 +54,6 @@ CFLAGS+=	-I${.CURDIR}/../../common -I${.CURDIR}/../common \
 # the location of libstand
 CFLAGS+=	-I${.CURDIR}/../../../../lib/libstand/
 
-.if ${CC:T:Mclang} == "clang"
-# XXX: clang integrated-as doesn't grok .codeNN directives yet
-CFLAGS+=	${.IMPSRC:T:Mamd64_tramp.S:C/^.+$/-no-integrated-as/}
-.endif
-
 .if ${MACHINE_CPUARCH} == "amd64"
 CLEANFILES+=	machine
 machine:
@@ -67,6 +62,10 @@ machine:
 
 .include <bsd.lib.mk>
 
+# XXX: clang integrated-as doesn't grok .codeNN directives yet
+CFLAGS.amd64_tramp.S=	${CLANG_NO_IAS}
+CFLAGS+=		${CFLAGS.${.IMPSRC:T}}
+
 .if ${MACHINE_CPUARCH} == "amd64"
 beforedepend ${OBJS}: machine
 .endif
diff --git a/sys/boot/i386/pxeldr/Makefile b/sys/boot/i386/pxeldr/Makefile
index 0290632..f4fd65d 100644
--- a/sys/boot/i386/pxeldr/Makefile
+++ b/sys/boot/i386/pxeldr/Makefile
@@ -23,11 +23,6 @@ CFLAGS+=-DPROBE_KEYBOARD
 CFLAGS+=-DALWAYS_SERIAL
 .endif
 
-.if ${CC:T:Mclang} == "clang"
-# XXX: clang integrated-as doesn't grok .codeNN directives yet
-CFLAGS+=${.IMPSRC:T:Mpxeldr.S:C/^.+$/-no-integrated-as/}
-.endif
-
 LOADERBIN= ${.OBJDIR}/../loader/loader.bin
 
 CLEANFILES+= ${BOOT}.tmp
@@ -46,3 +41,7 @@ ${LOADER}: ${LOADERBIN} ${BTXLDR} ${BTXKERN}
 	    -b ${BTXKERN} ${LOADERBIN}
 
 .include <bsd.prog.mk>
+
+# XXX: clang integrated-as doesn't grok .codeNN directives yet
+CFLAGS.pxeldr.S=	${CLANG_NO_IAS}
+CFLAGS+=		${CFLAGS.${.IMPSRC:T}}
diff --git a/sys/boot/i386/zfsboot/Makefile b/sys/boot/i386/zfsboot/Makefile
index 024fa25..b2db778 100644
--- a/sys/boot/i386/zfsboot/Makefile
+++ b/sys/boot/i386/zfsboot/Makefile
@@ -31,11 +31,6 @@ CFLAGS=	-DBOOTPROG=\"zfsboot\" \
 	-Wpointer-arith -Wshadow -Wstrict-prototypes -Wwrite-strings \
 	-Winline --param max-inline-insns-single=100
 
-.if ${CC:T:Mclang} == "clang"
-# XXX: clang integrated-as doesn't grok .codeNN directives yet
-CFLAGS+=	${.IMPSRC:T:Mzfsldr.S:C/^.+$/-no-integrated-as/}
-.endif
-
 LDFLAGS=-static -N --gc-sections
 
 # Pick up ../Makefile.inc early.
@@ -90,3 +85,7 @@ machine:
 .endif
 
 .include <bsd.prog.mk>
+
+# XXX: clang integrated-as doesn't grok .codeNN directives yet
+CFLAGS.zfsldr.S=	${CLANG_NO_IAS}
+CFLAGS+=		${CFLAGS.${.IMPSRC:T}}