On Wed, 13 Mar 2013, Benjamin De Kosnik wrote: > Hey! Here is the first pass at the 4.8 porting documentation.
Lovely, thank you, I know this really has proven useful. And with some unfortunate of delay, some updates from my side: - Use run-time performance (instead of runtime performance which Sandra established as the performance of the runtime, I think). - Code does not use warning options per se. - Undefined behavior is undefined regardless of how involved optimizers are. - Improve markup, fix grammar, break long lines. - Refer to GNU/Linux. Applied. Gerald Index: porting_to.html =================================================================== RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-4.8/porting_to.html,v retrieving revision 1.5 diff -u -r1.5 porting_to.html --- porting_to.html 11 Jun 2014 18:49:26 -0000 1.5 +++ porting_to.html 12 Apr 2015 00:14:41 -0000 @@ -13,7 +13,7 @@ <a href="https://gcc.gnu.org/gcc-4.8/changes.html";>changes</a>. Some of these are a result of bug fixing, and some old behaviors have been intentionally changed in order to support new standards, or relaxed -in standards-conforming ways to facilitate compilation or runtime +in standards-conforming ways to facilitate compilation or run-time performance. Some of these changes are not visible to the naked eye and will not cause problems when updating from older versions. </p> @@ -31,9 +31,8 @@ <p>Improvements to the GCC infrastructure allow improvements in the ability of several existing warnings to spot problematic code. As -such, new warnings may exist for previously warning-free code that -uses -<code>-Wmaybe-uninitialized</code>. +such, new warnings may exist for previously warning-free code when +using <code>-Wmaybe-uninitialized</code>. </p> <p> Although these warnings will @@ -49,8 +48,8 @@ <h3>More aggressive loop optimizations</h3> <p>Improvements to the GCC infrastructure allow improvements in -the ability of the optimizers to transform loops. Some loops that previously -invoked undefined behavior may now be turned into endless loops. +the ability of the optimizers to transform loops. Some loops that +invoke undefined behavior may now be turned into endless loops. </p> <p>For example,</p> @@ -68,7 +67,8 @@ </pre> <p> -When fd is 64 or above, fd * 0x02000001 overflows, which is invalid in C/C++ for signed ints. +When fd is 64 or above, fd * 0x02000001 overflows, which is invalid for +signed ints in C/C++. </p> <p> @@ -119,13 +119,13 @@ ^ </pre> -<p>Although these warnings will not result in compilation failure, -often <code>-Wall</code> is used in conjunction with +<p>Although these warnings will not result in compilation failure per +se, often <code>-Wall</code> is used in conjunction with <code>-Werror</code> and as a result, new warnings are turned into new errors.</p> -<p>To fix, either re-write to use memcpy or dereference the last argument in the -offending memset call.</p> +<p>To fix, either re-write to use <code>memcpy</code> or dereference the +last argument in the offending <code>memset</code> call.</p> <p>As a workaround, use <code>-Wno-sizeof-pointer-memaccess</code>. @@ -134,7 +134,7 @@ <h3>Pre-processor pre-includes</h3> <p> -The GCC pre-processor may now pre-includes a file that defines certain +The GCC pre-processor may now pre-include a file that defines certain macros for the entirety of the translation unit. This allows fully conformant implementations of C99/C11 and other standards that require compiler or compiler + runtime macros that describe @@ -142,7 +142,7 @@ </p> <p> -On linux, <stdc-predef.h> is pre-included. +On GNU/Linux, <stdc-predef.h> is pre-included. </p> <p> @@ -154,8 +154,9 @@ /usr/include/stdc-predef.h:0: error: Syntax error near '3' </pre> -<p>As a workaround, the stdc-predef.h preinclude can be disabled with -the use of <code>-ffreestanding</code>. For non C/C++ code, use the pre-processor flag <code>-P</code>. +<p>As a workaround, the stdc-predef.h pre-include can be disabled with +the use of <code>-ffreestanding</code>. For non C/C++ code, use the +pre-processor flag <code>-P</code>. </p> <h2>C++ language issues</h2>
