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2004-05-13  Jonathan Wakely  <redi@gcc.gnu.org>

	* docs/html/abi.html: Document effect of -fabi-version on value
	of __GXX_ABI_VERSION, and that it's defined in c-cppbuiltin.c.
	Fix markup.

From-SVN: r81794
This commit is contained in:
Jonathan Wakely 2004-05-13 16:50:02 +01:00
parent 520f0c4803
commit d7f3083354
2 changed files with 105 additions and 76 deletions
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libstdc++-v3/ChangeLog
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@ -1,3 +1,9 @@
2004-05-13 Jonathan Wakely <redi@gcc.gnu.org>
* docs/html/abi.html: Document effect of -fabi-version on value
of __GXX_ABI_VERSION, and that it's defined in c-cppbuiltin.c.
Fix markup.
2004-05-13 Benjamin Kosnik <bkoz@redhat.com> 2004-05-13 Benjamin Kosnik <bkoz@redhat.com>
PR libstdc++/15074 PR libstdc++/15074

169
libstdc++-v3/docs/html/abi.html
View File

@ -32,7 +32,7 @@
<!-- ####################################################### --> <!-- ####################################################### -->
<hr /> <hr />
<h3 class="left"> <h3 class="left">
<a name="C++interface">The C++ interface</a> <a name="CXXinterface">The C++ interface</a>
</h3> </h3>
<p> C++ applications often dependent on specific language support <p> C++ applications often dependent on specific language support
@ -101,7 +101,7 @@ given compiler ABI. In a nutshell:
</p> </p>
<h3 class="left"> <h3 class="left">
<a name="ABI versioning">Versioning</a> <a name="ABI_versioning">Versioning</a>
</h3> </h3>
<p> The C++ interface has evolved throughout the history of the GNU <p> The C++ interface has evolved throughout the history of the GNU
@ -170,8 +170,8 @@ on ELF systems).</p>
<li>gcc-3.3.3: libgcc_s.so.1</li> <li>gcc-3.3.3: libgcc_s.so.1</li>
<li>gcc-3.4.0: libgcc_s.so.1</li> <li>gcc-3.4.0: libgcc_s.so.1</li>
</ul> </ul>
</li>
<p></p> <p></p>
</li>
<li>Release versioning on the libstdc++.so binary, implemented in the same was as the libgcc_s.so binary, above. <li>Release versioning on the libstdc++.so binary, implemented in the same was as the libgcc_s.so binary, above.
@ -195,8 +195,8 @@ on ELF systems).</p>
<li>gcc-3.3.3: libstdc++.so.5.0.5</li> <li>gcc-3.3.3: libstdc++.so.5.0.5</li>
<li>gcc-3.4.0: libstdc++.so.6.0.0</li> <li>gcc-3.4.0: libstdc++.so.6.0.0</li>
</ul> </ul>
</li>
<p></p> <p></p>
</li>
<li>Symbol versioning on the libgcc_s.so binary. <li>Symbol versioning on the libgcc_s.so binary.
<p>mapfile: gcc/libgcc-std.ver</p> <p>mapfile: gcc/libgcc-std.ver</p>
@ -220,8 +220,8 @@ on ELF systems).</p>
<li>gcc-3.3.3: GCC_3.0</li> <li>gcc-3.3.3: GCC_3.0</li>
<li>gcc-3.4.0: GCC_3.0</li> <li>gcc-3.4.0: GCC_3.0</li>
</ul> </ul>
</li>
<p></p> <p></p>
</li>
<li>Symbol versioning on the libstdc++.so binary. <li>Symbol versioning on the libstdc++.so binary.
@ -254,8 +254,8 @@ on ELF systems).</p>
<li>gcc-3.3.3: GLIBCPP_3.2.3, CXXABI_1.2.1</li> <li>gcc-3.3.3: GLIBCPP_3.2.3, CXXABI_1.2.1</li>
<li>gcc-3.4.0: GLIBCXX_3.4, CXXABI_1.3</li> <li>gcc-3.4.0: GLIBCXX_3.4, CXXABI_1.3</li>
</ul> </ul>
</li>
<p></p> <p></p>
</li>
<li> <li>
<p>Incremental bumping of a compiler pre-defined macro, <p>Incremental bumping of a compiler pre-defined macro,
@ -266,22 +266,26 @@ on ELF systems).</p>
</p> </p>
<p> <p>
This macro is defined in the file "lang-specs.h" in the gcc/cp directory. This macro was defined in the file "lang-specs.h" in the gcc/cp directory.
Later versions define it in "c-common.c" in the gcc directory. Later versions defined it in "c-common.c" in the gcc directory, and from
G++ 3.4 it is defined in c-cppbuiltin.c and its value determined by the
'-fabi-version' command line option.
</p> </p>
<p> <p>
It is versioned as follows: It is versioned as follows, where 'n' is given by '-fabi-version=n':
</p> </p>
<ul> <ul>
<li>gcc-3.0.x: 100</li> <li>gcc-3.0.x: 100</li>
<li>gcc-3.1.x: 100 (Error, should be 101)</li> <li>gcc-3.1.x: 100 (Error, should be 101)</li>
<li>gcc-3.2.x: 102</li> <li>gcc-3.2.x: 102</li>
<li>gcc-3.3.x: 102</li> <li>gcc-3.3.x: 102</li>
<li>gcc-3.4.x: 1002</li> <li>gcc-3.4.x: 102 (when n=1)</li>
<li>gcc-3.4.x: 1000+n (when n&gt;1)</li>
<li>gcc-3.4.x: 999999 (when n=0)</li>
</ul> </ul>
</li>
<p></p> <p></p>
</li>
<li> <li>
<p>Changes to the default compiler option for <p>Changes to the default compiler option for
@ -297,8 +301,8 @@ on ELF systems).</p>
<li>gcc-3.3.x: <code>-fabi-version=1</code></li> <li>gcc-3.3.x: <code>-fabi-version=1</code></li>
<li>gcc-3.4.x: <code>-fabi-version=2</code></li> <li>gcc-3.4.x: <code>-fabi-version=2</code></li>
</ul> </ul>
</li>
<p></p> <p></p>
</li>
<li> <li>
<p>Incremental bumping of a library pre-defined macro. For releases <p>Incremental bumping of a library pre-defined macro. For releases
@ -335,8 +339,8 @@ on ELF systems).</p>
<li>gcc-3.3.3: 20040214</li> <li>gcc-3.3.3: 20040214</li>
<li>gcc-3.4.0: 20040419</li> <li>gcc-3.4.0: 20040419</li>
</ul> </ul>
</li>
<p></p> <p></p>
</li>
<li> <li>
@ -344,7 +348,8 @@ on ELF systems).</p>
Incremental bumping of a library pre-defined macro, Incremental bumping of a library pre-defined macro,
_GLIBCPP_VERSION. This macro is defined as the released version of _GLIBCPP_VERSION. This macro is defined as the released version of
the library, as a string literal. This is only implemented in the library, as a string literal. This is only implemented in
gcc-3.1.0 releases and higher, and is deprecated in 3.4. gcc-3.1.0 releases and higher, and is deprecated in 3.4 (where it
is called _GLIBCXX_VERSION).
</p> </p>
<p> <p>
@ -375,8 +380,8 @@ on ELF systems).</p>
<li>gcc-3.3.3: "3.3.3"</li> <li>gcc-3.3.3: "3.3.3"</li>
<li>gcc-3.4.0: "version-unused"</li> <li>gcc-3.4.0: "version-unused"</li>
</ul> </ul>
</li>
<p></p> <p></p>
</li>
<li> <li>
<p> <p>
@ -389,7 +394,7 @@ on ELF systems).</p>
directory hierarchy corresponding to the C++ compiler's released directory hierarchy corresponding to the C++ compiler's released
version. This version corresponds to the variable "gcc_version" in version. This version corresponds to the variable "gcc_version" in
"libstdc++-v3/acinclude.m4," and more details can be found in that "libstdc++-v3/acinclude.m4," and more details can be found in that
file's macro GLIBCPP_CONFIGURE. file's macro GLIBCXX_CONFIGURE (GLIBCPP_CONFIGURE before gcc-3.4.0).
</p> </p>
<p> <p>
C++ includes are versioned as follows: C++ includes are versioned as follows:
@ -412,8 +417,8 @@ on ELF systems).</p>
<li>gcc-3.3.3: include/c++/3.3.3</li> <li>gcc-3.3.3: include/c++/3.3.3</li>
<li>gcc-3.4.0: include/c++/3.4.0</li> <li>gcc-3.4.0: include/c++/3.4.0</li>
</ul> </ul>
</li>
<p></p> <p></p>
</li>
</ul> </ul>
<p> <p>
Taken together, these techniques can accurately specify interface Taken together, these techniques can accurately specify interface
@ -457,7 +462,7 @@ on ELF systems).</p>
impact versioning and compatibility. impact versioning and compatibility.
</p> </p>
</p> <p>
For more information on configure options, including ABI impacts, see: For more information on configure options, including ABI impacts, see:
http://gcc.gnu.org/onlinedocs/libstdc++/configopts.html http://gcc.gnu.org/onlinedocs/libstdc++/configopts.html
</p> </p>
@ -507,11 +512,11 @@ int main()
%g++ hello.cc -o hello.out %g++ hello.cc -o hello.out
%ldd hello.out %ldd hello.out
libstdc++.so.5 => /usr/lib/libstdc++.so.5 (0x00764000) libstdc++.so.5 =&gt; /usr/lib/libstdc++.so.5 (0x00764000)
libm.so.6 => /lib/tls/libm.so.6 (0x004a8000) libm.so.6 =&gt; /lib/tls/libm.so.6 (0x004a8000)
libgcc_s.so.1 => /mnt/hd/bld/gcc/gcc/libgcc_s.so.1 (0x40016000) libgcc_s.so.1 =&gt; /mnt/hd/bld/gcc/gcc/libgcc_s.so.1 (0x40016000)
libc.so.6 => /lib/tls/libc.so.6 (0x0036d000) libc.so.6 =&gt; /lib/tls/libc.so.6 (0x0036d000)
/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x00355000) /lib/ld-linux.so.2 =&gt; /lib/ld-linux.so.2 (0x00355000)
%nm hello.out %nm hello.out
</pre> </pre>
@ -524,7 +529,7 @@ of the name, then the executable is versioned. Here's an example:
<code> U _ZNSt8ios_base4InitC1Ev@@GLIBCXX_3.4 </code> <code> U _ZNSt8ios_base4InitC1Ev@@GLIBCXX_3.4 </code>
<h3 class="left"> <h3 class="left">
<a name="ABI allowed">Library allowed ABI changes</a> <a name="ABI_allowed">Library allowed ABI changes</a>
</h3> </h3>
<p> <p>
The following will cause the library minor version number to The following will cause the library minor version number to
@ -543,7 +548,7 @@ Other allowed changes are possible.
<h3 class="left"> <h3 class="left">
<a name="ABI disallowed">Library disallowed ABI changes</a> <a name="ABI_disallowed">Library disallowed ABI changes</a>
</h3> </h3>
<p> <p>
@ -574,24 +579,24 @@ number to increase, say from "libstdc++.so.3.0.4" to
</h3> </h3>
<ul> <ul>
<li>Separation of interface and implementation</li> <li>Separation of interface and implementation
<p>This is accomplished by two techniques that separate the API from <p>This is accomplished by two techniques that separate the API from
the ABI: forcing undefined references to link against a library binary the ABI: forcing undefined references to link against a library binary
for definitions. for definitions.
</p> </p>
<ul> <dl>
<li>Include files have declarations, source files have defines</li> <dt>Include files have declarations, source files have defines</dt>
<p> For non-templatized types, such as much of <code>class <dd> For non-templatized types, such as much of <code>class
locale</code>, the appropriate standard C++ include, say locale</code>, the appropriate standard C++ include, say
<code>locale</code>, can contain full declarations, while various <code>locale</code>, can contain full declarations, while various
source files (say <code> locale.cc, locale_init.cc, source files (say <code> locale.cc, locale_init.cc,
localename.cc</code>) contain definitions.</p> localename.cc</code>) contain definitions.</dd>
<li>Extern template on required types</li> <dt>Extern template on required types</dt>
<p>For parts of the standard that have an explicit list of required <dd>For parts of the standard that have an explicit list of required
instantiations, the GNU extension syntax <code> extern template instantiations, the GNU extension syntax <code> extern template
</code> can be used to control where template definitions </code> can be used to control where template definitions
reside. By marking required instantiations as <code> extern reside. By marking required instantiations as <code> extern
@ -601,14 +606,15 @@ localename.cc</code>) contain definitions.</p>
on parts of the standard that require <code> char</code> and <code> on parts of the standard that require <code> char</code> and <code>
wchar_t</code> instantiations, and includes <code> wchar_t</code> instantiations, and includes <code>
basic_string</code>, the locale facets, and the types in <code> basic_string</code>, the locale facets, and the types in <code>
iostreams</code>.</p> iostreams</code>.</dd>
</ul> </dl>
<p> In addition, these techniques have the additional benefit that <p> In addition, these techniques have the additional benefit that
they reduce binary size, which can increase runtime performance. they reduce binary size, which can increase runtime performance.
</p> </p>
</li>
<li>Namespaces linking symbol definitions to export mapfiles</li> <li>Namespaces linking symbol definitions to export mapfiles
<p>All symbols in the shared library binary are processed by a linker <p>All symbols in the shared library binary are processed by a linker
script at build time that either allows or disallows external script at build time that either allows or disallows external
@ -623,34 +629,37 @@ impacting ABI compatibility.
<p>The following namespaces are transformed by the mapfile:</p> <p>The following namespaces are transformed by the mapfile:</p>
<ul> <dl>
<li><code>namespace std</code></li> <dt><code>namespace std</code></dt>
<p> Defaults to exporting all symbols in label <dd> Defaults to exporting all symbols in label
<code>GLIBCXX</code> that do not begin with an underscore, ie <code>GLIBCXX</code> that do not begin with an underscore, ie
<code>__test_func</code> would not be exported by default. Select <code>__test_func</code> would not be exported by default. Select
exceptional symbols are allowed to be visible.</p> exceptional symbols are allowed to be visible.</dd>
<li><code>namespace __gnu_cxx</code></li> <dt><code>namespace __gnu_cxx</code></dt>
<p> Defaults to not exporting any symbols in label <dd> Defaults to not exporting any symbols in label
<code>GLIBCXX</code>, select items are allowed to be visible.</p> <code>GLIBCXX</code>, select items are allowed to be visible.</dd>
<li><code>namespace __gnu_internal</code></li> <dt><code>namespace __gnu_internal</code></dt>
<p> Defaults to not exported, no items are allowed to be visible.</p> <dd> Defaults to not exported, no items are allowed to be visible.</dd>
<li><code>namespace __cxxabiv1</code>, aliased to <code> namespace abi</code></li> <dt><code>namespace __cxxabiv1</code>, aliased to <code> namespace abi</code></dt>
<p> Defaults to not exporting any symbols in label <dd> Defaults to not exporting any symbols in label
<code>CXXABI</code>, select items are allowed to be visible.</p> <code>CXXABI</code>, select items are allowed to be visible.</dd>
</ul> </dl>
<p> <p>
</p> </p>
</li>
<li>Freezing the API</li> <li>Freezing the API
<p>Disallowed changes, as above, are not made on a stable release <p>Disallowed changes, as above, are not made on a stable release
branch. Enforcement tends to be less strict with GNU extensions that branch. Enforcement tends to be less strict with GNU extensions that
standard includes.</p> </ul> standard includes.</p>
</li>
</ul>
<h3 class="left"> <h3 class="left">
<a name="ABI testing">Testing ABI changes</a> <a name="ABI_testing">Testing ABI changes</a>
</h3> </h3>
<p> <p>
@ -743,7 +752,7 @@ us. We'd like to know about them!
</p> </p>
<h3 class="left"> <h3 class="left">
<a name="ABI multi testing">Testing Multi-ABI binaries</a> <a name="ABI_multi_testing">Testing Multi-ABI binaries</a>
</h3> </h3>
<p> <p>
@ -784,18 +793,18 @@ exceptions, locale, etc.
<p> ...with the resulting libraries looking like </p> <p> ...with the resulting libraries looking like </p>
<pre> <pre>
%ldd libone.so.1.0.0 %ldd libone.so.1.0.0
libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x40016000) libstdc++.so.6 =&gt; /usr/lib/libstdc++.so.6 (0x40016000)
libm.so.6 => /lib/tls/libm.so.6 (0x400fa000) libm.so.6 =&gt; /lib/tls/libm.so.6 (0x400fa000)
libgcc_s.so.1 => /mnt/hd/bld/gcc/gcc/libgcc_s.so.1 (0x4011c000) libgcc_s.so.1 =&gt; /mnt/hd/bld/gcc/gcc/libgcc_s.so.1 (0x4011c000)
libc.so.6 => /lib/tls/libc.so.6 (0x40125000) libc.so.6 =&gt; /lib/tls/libc.so.6 (0x40125000)
/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x00355000) /lib/ld-linux.so.2 =&gt; /lib/ld-linux.so.2 (0x00355000)
%ldd libtwo.so.1.0.0 %ldd libtwo.so.1.0.0
libstdc++.so.5 => /usr/lib/libstdc++.so.5 (0x40027000) libstdc++.so.5 =&gt; /usr/lib/libstdc++.so.5 (0x40027000)
libm.so.6 => /lib/tls/libm.so.6 (0x400e1000) libm.so.6 =&gt; /lib/tls/libm.so.6 (0x400e1000)
libgcc_s.so.1 => /mnt/hd/bld/gcc/gcc/libgcc_s.so.1 (0x40103000) libgcc_s.so.1 =&gt; /mnt/hd/bld/gcc/gcc/libgcc_s.so.1 (0x40103000)
libc.so.6 => /lib/tls/libc.so.6 (0x4010c000) libc.so.6 =&gt; /lib/tls/libc.so.6 (0x4010c000)
/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x00355000) /lib/ld-linux.so.2 =&gt; /lib/ld-linux.so.2 (0x00355000)
</pre> </pre>
@ -810,12 +819,12 @@ Which gives the expected:
</p> </p>
<pre> <pre>
%ldd a.out %ldd a.out
libstdc++.so.5 => /usr/lib/libstdc++.so.5 (0x00764000) libstdc++.so.5 =&gt; /usr/lib/libstdc++.so.5 (0x00764000)
libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x40015000) libstdc++.so.6 =&gt; /usr/lib/libstdc++.so.6 (0x40015000)
libc.so.6 => /lib/tls/libc.so.6 (0x0036d000) libc.so.6 =&gt; /lib/tls/libc.so.6 (0x0036d000)
libm.so.6 => /lib/tls/libm.so.6 (0x004a8000) libm.so.6 =&gt; /lib/tls/libm.so.6 (0x004a8000)
libgcc_s.so.1 => /mnt/hd/bld/gcc/gcc/libgcc_s.so.1 (0x400e5000) libgcc_s.so.1 =&gt; /mnt/hd/bld/gcc/gcc/libgcc_s.so.1 (0x400e5000)
/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x00355000) /lib/ld-linux.so.2 =&gt; /lib/ld-linux.so.2 (0x00355000)
</pre> </pre>
<p> <p>
@ -830,28 +839,42 @@ dependent libstdc++.so.5.
<p> <p>
ABIcheck, a vague idea of checking ABI compatibility ABIcheck, a vague idea of checking ABI compatibility
http://abicheck.sourceforge.net/ <br />
<a href="http://abicheck.sourceforge.net/">http://abicheck.sourceforge.net/</a>
</p>
<p> <p>
C++ ABI reference C++ ABI reference
http://www.codesourcery.com/cxx-abi/ <br />
<a href="http://www.codesourcery.com/cxx-abi/">http://www.codesourcery.com/cxx-abi/</a>
</p> </p>
<p> <p>
Intel ABI documentation Intel ABI documentation
<br />
"Intel® Compilers for Linux* -Compatibility with the GNU Compilers" "Intel® Compilers for Linux* -Compatibility with the GNU Compilers"
<br />
(included in icc 6.0) (included in icc 6.0)
</p> </p>
<p> <p>
Sun Solaris 2.9 docs Sun Solaris 2.9 docs
<br />
Linker and Libraries Guide (document 816-1386) Linker and Libraries Guide (document 816-1386)
<br />
C++ Migration Guide (document 816-2459) C++ Migration Guide (document 816-2459)
http://docs.sun.com/db/prod/solaris.9 <br />
http://docs.sun.com/?p=/doc/816-1386&a=load <a href="http://docs.sun.com/db/prod/solaris.9">http://docs.sun.com/db/prod/solaris.9</a>
<br />
<a href="http://docs.sun.com/?p=/doc/816-1386&amp;a=load">http://docs.sun.com/?p=/doc/816-1386&amp;a=load</a>
</p> </p>
<p> <p>
Ulrich Drepper, "ELF Symbol Versioning" Ulrich Drepper, "ELF Symbol Versioning"
http://people.redhat.com/drepper/symbol-versioning <br />
<a href="http://people.redhat.com/drepper/symbol-versioning">http://people.redhat.com/drepper/symbol-versioning</a>
</p> </p>
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