diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 9965b90bca1823c5e7aed95b933bad18563d34de..d5b8370daf1a0f8ba69a001a31b801a26c37e73b 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,7 @@ +2003-04-22 Nathan Sidwell <nathan@codesourcery.com> + + * ginclude/stddef.h: Provide C++ safe offsetof. + 2003-04-22 J"orn Rennecke <joern.rennecke@superh.com> * function.c (purge_addressof_1): In (mem (addressof (reg))) case diff --git a/gcc/ginclude/stddef.h b/gcc/ginclude/stddef.h index f1046f44bb1447a852205fb25f6008d4626b3620..ad091ea1383f52fa6831b2d2484345e20fce642c 100644 --- a/gcc/ginclude/stddef.h +++ b/gcc/ginclude/stddef.h @@ -410,8 +410,14 @@ typedef __WINT_TYPE__ wint_t; #ifdef _STDDEF_H /* Offset of member MEMBER in a struct of type TYPE. */ - +#ifndef __cplusplus #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER) +#else /* C++ */ +/* The reference cast is necessary to thwart an operator& that might + be applicable to MEMBER's type. See DR 273 for details. */ +#define offsetof(TYPE, MEMBER) (reinterpret_cast <size_t> \ + (&reinterpret_cast <char &>(static_cast <TYPE *> (0)->MEMBER))) +#endif /* C++ */ #endif /* _STDDEF_H was defined this time */ diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 577a6090432b0e8df41f2525ba575e9d87e0f375..8328263e424b4b1541e42c6567ddf24c6b16e7fc 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2003-04-22 Nathan Sidwell <nathan@codesourcery.com> + + * g++.dg/other/offsetof2.C: New test. + 2003-04-21 Mark Mitchell <mark@codesourcery.com> * g++.dg/template/recurse.C: Adjust location of error messages. diff --git a/gcc/testsuite/g++.dg/other/offsetof2.C b/gcc/testsuite/g++.dg/other/offsetof2.C new file mode 100644 index 0000000000000000000000000000000000000000..3ab63981d9b35facdd5eb5b5c3eddd590e0f5d6b --- /dev/null +++ b/gcc/testsuite/g++.dg/other/offsetof2.C @@ -0,0 +1,47 @@ +// { dg-do run } +// { dg-options -Wold-style-cast } + +// Copyright (C) 2003 Free Software Foundation, Inc. +// Contributed by Nathan Sidwell 22 Apr 2003 <nathan@codesourcery.com> + +// DR273 POD can have an operator&, offsetof is still required to work + +#include <stddef.h> + +struct POD1 +{ + int m; + + void *operator& () const {return 0;} // yes, still a pod! +}; + +struct POD2 +{ + int m; +}; + +void *operator& (POD2 const &) {return 0;} // ouch! + +struct POD3 +{ + int prefix; + + POD1 m; +}; + +struct POD4 +{ + int prefix; + + POD1 m; +}; + +int main () +{ + if (offsetof (POD3, m) != sizeof (int)) + return 1; + if (offsetof (POD4, m) != sizeof (int)) + return 2; + return 0; +} +