diff options
Diffstat (limited to 'gcc/doc/invoke.texi')
| -rw-r--r-- | gcc/doc/invoke.texi | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index d1eb317..faa7fa9 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -325,6 +325,7 @@ Objective-C and Objective-C++ Dialects}. -Winaccessible-base @gol -Winit-self -Winline -Wno-int-conversion -Wint-in-bool-context @gol -Wno-int-to-pointer-cast -Winvalid-memory-model -Wno-invalid-offsetof @gol +-Wzero-length-bounds @gol -Winvalid-pch -Wlarger-than=@var{byte-size} @gol -Wlogical-op -Wlogical-not-parentheses -Wlong-long @gol -Wmain -Wmaybe-uninitialized -Wmemset-elt-size -Wmemset-transposed-args @gol @@ -4438,6 +4439,7 @@ Options} and @ref{Objective-C and Objective-C++ Dialect Options}. -Wimplicit-int @r{(C and Objective-C only)} @gol -Wimplicit-function-declaration @r{(C and Objective-C only)} @gol -Winit-self @r{(only for C++)} @gol +-Wzero-length-bounds @gol -Wlogical-not-parentheses @gol -Wmain @r{(only for C/ObjC and unless} @option{-ffreestanding}@r{)} @gol -Wmaybe-uninitialized @gol @@ -6330,6 +6332,33 @@ conversions. This warning is about implicit conversions; for explicit conversions the warnings @option{-Wno-int-to-pointer-cast} and @option{-Wno-pointer-to-int-cast} may be used. +@item -Wzero-length-bounds +@opindex Wzero-length-bounds +@opindex Wzero-length-bounds +Warn about accesses to elements of zero-length array members that might +overlap other members of the same object. Declaring interior zero-length +arrays is discouraged because accesses to them are undefined. See +@xref{Zero Length}. + +For example, the first two stores in function @code{bad} are diagnosed +because the array elements overlap the subsequent members @code{b} and +@code{c}. The third store is diagnosed by @option{-Warray-bounds} +because it is beyond the bounds of the enclosing object. + +@smallexample +struct X @{ int a[0]; int b, c; @}; +struct X x; + +void bad (void) +@{ + x.a[0] = 0; // -Wzero-length-bounds + x.a[1] = 1; // -Wzero-length-bounds + x.a[2] = 2; // -Warray-bounds +@} +@end smallexample + +Option @option{-Wzero-length-bounds} is enabled by @option{-Warray-bounds}. + @item -Wno-div-by-zero @opindex Wno-div-by-zero @opindex Wdiv-by-zero |