diff options
Diffstat (limited to 'contrib/gcc/cp/gxxint.texi')
| -rw-r--r-- | contrib/gcc/cp/gxxint.texi | 150 |
1 files changed, 36 insertions, 114 deletions
diff --git a/contrib/gcc/cp/gxxint.texi b/contrib/gcc/cp/gxxint.texi index 7cb57f2..05f1373 100644 --- a/contrib/gcc/cp/gxxint.texi +++ b/contrib/gcc/cp/gxxint.texi @@ -23,7 +23,6 @@ Questions and comments to Benjamin Kosnik @code{<bkoz@@cygnus.com>}. * Access Control:: * Error Reporting:: * Parser:: -* Copying Objects:: * Exception Handling:: * Free Store:: * Mangling:: Function name mangling for C++ and Java @@ -167,77 +166,6 @@ class foo @{ public: int b; int a; foo (); @}; Thus, @samp{b} will be initialized with 2 first, then @samp{a} will be initialized with 1, regardless of how they're listed in the mem-initializer. -@item Argument Matching - -In early 1993, the argument matching scheme in @sc{gnu} C++ changed -significantly. The original code was completely replaced with a new -method that will, hopefully, be easier to understand and make fixing -specific cases much easier. - -The @samp{-fansi-overloading} option is used to enable the new code; at -some point in the future, it will become the default behavior of the -compiler. - -The file @file{cp-call.c} contains all of the new work, in the functions -@code{rank_for_overload}, @code{compute_harshness}, -@code{compute_conversion_costs}, and @code{ideal_candidate}. - -Instead of using obscure numerical values, the quality of an argument -match is now represented by clear, individual codes. The new data -structure @code{struct harshness} (it used to be an @code{unsigned} -number) contains: - -@enumerate a -@item the @samp{code} field, to signify what was involved in matching two -arguments; -@item the @samp{distance} field, used in situations where inheritance -decides which function should be called (one is ``closer'' than -another); -@item and the @samp{int_penalty} field, used by some codes as a tie-breaker. -@end enumerate - -The @samp{code} field is a number with a given bit set for each type of -code, OR'd together. The new codes are: - -@itemize @bullet -@item @code{EVIL_CODE} -The argument was not a permissible match. - -@item @code{CONST_CODE} -Currently, this is only used by @code{compute_conversion_costs}, to -distinguish when a non-@code{const} member function is called from a -@code{const} member function. - -@item @code{ELLIPSIS_CODE} -A match against an ellipsis @samp{...} is considered worse than all others. - -@item @code{USER_CODE} -Used for a match involving a user-defined conversion. - -@item @code{STD_CODE} -A match involving a standard conversion. - -@item @code{PROMO_CODE} -A match involving an integral promotion. For these, the -@code{int_penalty} field is used to handle the ARM's rule (XXX cite) -that a smaller @code{unsigned} type should promote to a @code{int}, not -to an @code{unsigned int}. - -@item @code{QUAL_CODE} -Used to mark use of qualifiers like @code{const} and @code{volatile}. - -@item @code{TRIVIAL_CODE} -Used for trivial conversions. The @samp{int_penalty} field is used by -@code{convert_harshness} to communicate further penalty information back -to @code{build_overload_call_real} when deciding which function should -be call. -@end itemize - -The functions @code{convert_to_aggr} and @code{build_method_call} use -@code{compute_conversion_costs} to rate each argument's suitability for -a given candidate function (that's how we get the list of candidates for -@code{ideal_candidate}). - @item The Explicit Keyword The use of @code{explicit} on a constructor is used by @code{grokdeclarator} @@ -1002,7 +930,7 @@ To have the line number on the error message indicate the line of the DECL, use @code{cp_error_at} and its ilk; to indicate which argument you want, use @code{%+D}, or it will default to the first. -@node Parser, Copying Objects, Error Reporting, Top +@node Parser, Exception Handling, Error Reporting, Top @section Parser Some comments on the parser: @@ -1093,33 +1021,7 @@ conflicts. Unlike the others, this ambiguity is not recognized by the Working Paper. -@node Copying Objects, Exception Handling, Parser, Top -@section Copying Objects - -The generated copy assignment operator in g++ does not currently do the -right thing for multiple inheritance involving virtual bases; it just -calls the copy assignment operators for its direct bases. What it -should probably do is: - -1) Split up the copy assignment operator for all classes that have -vbases into "copy my vbases" and "copy everything else" parts. Or do -the trickiness that the constructors do to ensure that vbases don't get -initialized by intermediate bases. - -2) Wander through the class lattice, find all vbases for which no -intermediate base has a user-defined copy assignment operator, and call -their "copy everything else" routines. If not all of my vbases satisfy -this criterion, warn, because this may be surprising behavior. - -3) Call the "copy everything else" routine for my direct bases. - -If we only have one direct base, we can just foist everything off onto -them. - -This issue is currently under discussion in the core reflector -(2/28/94). - -@node Exception Handling, Free Store, Copying Objects, Top +@node Exception Handling, Free Store, Parser, Top @section Exception Handling Note, exception handling in g++ is still under development. @@ -1666,18 +1568,18 @@ as @samp{P} followed by the mangling of the class name. @subsection Squangled type compression -Squangling (enabled with the @samp{-fsquangle} option), utilizes -the @samp{B} code to indicate reuse of a previously -seen type within an indentifier. Types are recognized in a left to -right manner and given increasing values, which are -appended to the code in the standard manner. Ie, multiple digit numbers -are delimited by @samp{_} characters. A type is considered to be any -non primitive type, regardless of whether its a parameter, template -parameter, or entire template. Certain codes are considered modifiers -of a type, and are not included as part of the type. These are the -@samp{C}, @samp{V}, @samp{P}, @samp{A}, @samp{R}, and @samp{U} codes, -denoting constant, volatile, pointer, array, reference, and unsigned. -These codes may precede a @samp{B} type in order to make the required +Squangling (enabled with the @samp{-fsquangle} option), utilizes the +@samp{B} code to indicate reuse of a previously seen type within an +indentifier. Types are recognized in a left to right manner and given +increasing values, which are appended to the code in the standard +manner. Ie, multiple digit numbers are delimited by @samp{_} +characters. A type is considered to be any non primitive type, +regardless of whether its a parameter, template parameter, or entire +template. Certain codes are considered modifiers of a type, and are not +included as part of the type. These are the @samp{C}, @samp{V}, +@samp{P}, @samp{A}, @samp{R}, @samp{U} and @samp{u} codes, denoting +constant, volatile, pointer, array, reference, unsigned, and restrict. +These codes may precede a @samp{B} type in order to make the required modifications to the type. For example: @@ -1845,6 +1747,14 @@ Used to indicate a template function. @item i Encodes the C++ and Java @code{int} types. +@item I +Encodes typedef names of the form @code{int@var{n}_t}, where @var{n} is a +positive decimal number. The @samp{I} is followed by either two +hexidecimal digits, which encode the value of @var{n}, or by an +arbitrary number of hexidecimal digits between underscores. For +example, @samp{I40} encodes the type @code{int64_t}, and @samp{I_200_} +encodes the type @code{int512_t}. + @item J Indicates a complex type. @@ -1854,12 +1764,21 @@ Used by squangling to compress qualified names. @item l Encodes the C++ @code{long} type. +@item n +Immediate repeated type. Followed by the repeat count. + +@item N +Repeated type. Followed by the repeat count of the repeated type, +followed by the type index of the repeated type. Due to a bug in +g++ 2.7.2, this is only generated if index is 0. Superceded by +@samp{n} when squangling. + @item P Indicates a pointer type. Followed by the type pointed to. @item Q Used to mangle qualified names, which arise from nested classes. -Should also be used for namespaces (?). +Also used for namespaces. In Java used to mangle package-qualified names, and inner classes. @item r @@ -1888,11 +1807,14 @@ A modifier that indicates that the following integer type is unsigned. Also used to indicate that the following class or namespace name is encoded using Unicode-mangling. +@item u +The @code{restrict} type qualifier. + @item v Encodes the C++ and Java @code{void} types. @item V -A modified for a @code{const} type or method. +A modifier for a @code{volatile} type or method. @item w Encodes the C++ @code{wchar_t} type, and the Java @code{char} types. |
