From 7c19f81682b7a2d561c2988f29cda338282ab688 Mon Sep 17 00:00:00 2001 From: Janis Johnson Date: Tue, 3 Sep 2002 22:47:41 +0000 Subject: [PATCH] Makefile.in (TEXI_GCC_FILES): Add compat.texi. 2002-09-03 Janis Johnson * Makefile.in (TEXI_GCC_FILES): Add compat.texi. * doc/gcc.texi (Top): Add new chapter, Binary Compatibility, and include its file, compat.texi. * doc/compat.texi: New file with new chapter, Binary Compatibility. From-SVN: r56774 --- gcc/ChangeLog | 7 +++ gcc/Makefile.in | 2 +- gcc/doc/compat.texi | 115 ++++++++++++++++++++++++++++++++++++++++++++ gcc/doc/gcc.texi | 2 + 4 files changed, 125 insertions(+), 1 deletion(-) create mode 100644 gcc/doc/compat.texi diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 8f885546177..4f9ed3c96d4 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2002-09-03 Janis Johnson + + * Makefile.in (TEXI_GCC_FILES): Add compat.texi. + * doc/gcc.texi (Top): Add new chapter, Binary Compatibility, and + include its file, compat.texi. + * doc/compat.texi: New file with new chapter, Binary Compatibility. + 2002-09-03 Neil Booth Debian BTS Bug #157416 diff --git a/gcc/Makefile.in b/gcc/Makefile.in index 5a7709a1f19..0aa6abc3b11 100644 --- a/gcc/Makefile.in +++ b/gcc/Makefile.in @@ -2477,7 +2477,7 @@ TEXI_GCC_FILES = $(docdir)/gcc.texi $(docdir)/include/gcc-common.texi \ $(docdir)/invoke.texi $(docdir)/extend.texi $(docdir)/md.texi \ $(docdir)/objc.texi $(docdir)/gcov.texi $(docdir)/trouble.texi \ $(docdir)/bugreport.texi $(docdir)/service.texi \ - $(docdir)/contribute.texi $(docdir)/vms.texi \ + $(docdir)/contribute.texi $(docdir)/vms.texi $(docdir)/compat.texi \ $(docdir)/include/funding.texi $(docdir)/gnu.texi \ $(docdir)/include/gpl.texi $(docdir)/include/fdl.texi \ $(docdir)/contrib.texi $(docdir)/cppenv.texi $(docdir)/cppopts.texi diff --git a/gcc/doc/compat.texi b/gcc/doc/compat.texi new file mode 100644 index 00000000000..3e4ef89d7da --- /dev/null +++ b/gcc/doc/compat.texi @@ -0,0 +1,115 @@ +@c Copyright (C) 2002 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@node Compatibility +@chapter Binary Compatibility +@cindex binary compatibility +@cindex ABI +@cindex application binary interface + +Binary compatibility encompasses several related concepts: + +@table @dfn +@item application binary interface (ABI) +The set of runtime conventions followed by all of the tools that deal +with binary representations of a program, including compilers, assemblers, +linkers, and language runtime support. +Some ABIs are formal with a written specification, possibly designed +by multiple interested parties. Others are simply the way things are +actually done by a particular set of tools. + +@item ABI conformance +A compiler conforms to an ABI if it generates code that follows all of +the specifications enumerated by that ABI@. +A library conforms to an ABI if it is implemented according to that ABI@. +An application conforms to an ABI if it is built using tools that conform +to that ABI and does not contain source code that specifically changes +behavior specified by the ABI@. + +@item calling conventions +Calling conventions are a subset of an ABI that specify of how arguments +are passed and function results are returned. + +@item interoperability +Different sets of tools are interoperable if they generate files that +can be used in the same program. The set of tools includes compilers, +assemblers, linkers, libraries, header files, startup files, and debuggers. +Binaries produced by different sets of tools are not interoperable unless +they implement the same ABI@. This applies to different versions of the +same tools as well as tools from different vendors. + +@item intercallability +Whether a function in a binary built by one set of tools can call a +function in a binary built by a different set of tools is a subset +of interoperability. + +@item implementation-defined features +Language standards include lists of implementation-defined features whose +behavior can vary from one implementation to another. Some of these +features are normally covered by a platform's ABI and others are not. +The features that are not covered by an ABI generally affect how a +program behaves, but not intercallability. + +@item compatibility +Conformance to the same ABI and the same behavior of implementation-defined +features are both relevant for compatibility. +@end table + +The application binary interface implemented by a C or C++ compiler +affects code generation and runtime support for: + +@itemize @bullet +@item +size and alignment of data types +@item +layout of structured types +@item +calling conventions +@item +register usage conventions +@item +interfaces for runtime arithmetic support +@item +object file formats +@end itemize + +In addition, the application binary interface implemented by a C++ compiler +affects code generation and runtime support for: +@itemize @bullet +@item +name mangling +@item +exception handling +@item +invoking constructors and destructors +@item +layout, alignment, and padding of classes +@item +layout and alignment of virtual tables +@end itemize + +Some GCC compilation options cause the compiler to generate code that +does not conform to the platform's default ABI@. Other options cause +different program behavior for implementation-defined features that are +not covered by an ABI@. These options are provided for consistency with +other compilers that do not follow the platform's default ABI or the +usual behavior of implementation-defined features for the platform. +Be very careful about using such options. + +Most platforms have a well-defined ABI that covers C code, but ABIs +that cover C++ functionality are not yet common. + +Starting with GCC 3.2, GCC binary conventions for C++ are based on a +written, vendor-neutral C++ ABI that was designed to be specific to +64-bit Itanium but also includes generic specifications that apply to +any platform. +This C++ ABI is also implemented by other compiler vendors on some +platforms, notably GNU/Linux and BSD systems. +We have tried hard to provide a stable ABI that will be compatible with +future GCC releases, but it is possible that we will encounter problems +that make this difficult. Such problems could include different +interpretations of the C++ ABI by different vendors, bugs in the ABI, or +bugs in the implementation of the ABI in different compilers. +GCC's @code{-Wabi} switch warns when G++ generates code that is +probably not compatible with the C++ ABI@. diff --git a/gcc/doc/gcc.texi b/gcc/doc/gcc.texi index 4e9f2b701da..1e9fcf48e18 100644 --- a/gcc/doc/gcc.texi +++ b/gcc/doc/gcc.texi @@ -164,6 +164,7 @@ Introduction, gccint, GNU Compiler Collection (GCC) Internals}. * C Extensions:: GNU extensions to the C language family. * C++ Extensions:: GNU extensions to the C++ language. * Objective-C:: GNU Objective-C runtime features. +* Compatibility:: Binary Compatibility * Gcov:: gcov: a GCC test coverage program. * Trouble:: If you have trouble using GCC. * Bugs:: How, why and where to report bugs. @@ -188,6 +189,7 @@ Introduction, gccint, GNU Compiler Collection (GCC) Internals}. @include invoke.texi @include extend.texi @include objc.texi +@include compat.texi @include gcov.texi @include trouble.texi @include bugreport.texi