| Message ID | 4F103A8E.3020702@net-b.de |
|---|---|
| State | New |
| Headers | show |
On Fri, Jan 13, 2012 at 16:07, Tobias Burnus <burnus@net-b.de> wrote: > Dear all, > > the front end uses for array indices (gfc_index_integer_kind / > gfc_array_index_type) which is a signed integer of size POINTER_SIZE. > > The libgfortran library used to use > typedef ssize_t index_type; > which fails if sizeof(void*) is not sizeof(ssize_t); the latter is the case > on LP64 systems (see PR). As a minor nitpick, not necessarily: E.g. x86_64-linux-gnu and most 64-bit Unix targets are also LP64 (as in, long and pointer are 64 bits), but older releases work there as ssize_t is also 64 bits. The target in the PR is (was?) thus a bit "special", in that while it's LP64, ssize_t is smaller than 64 bits. > For 4.7 this was changed (in April 2011) to: > typedef ptrdiff_t index_type; > which makes more sense - and should be sufficient for LP64 systems. > > However, mixing an POINTER_SIZE type with ptrdiff_t only works if > sizeof(ptrdiff_t) == POINTER_SIZE; in principle, the maximally allowed size > of a variable can be smaller (e.g. page size) than the maximally allowed > pointer size. (sizeof() returns a result of type size_t). I do not know > whether such systems exist in practice and whether such a system is > supported by GCC. > > The attached patch makes let's the FE emit code of the same data type as > used in libgfortran - ptrdiff_t for the array indices. > > Build and regtested on x86-64-linux. > OK for the trunk? Ok, thanks.
2012-01-13 Tobias Burnus <burnus@net-b.de> PR fortran/51842 * fortran/trans-types.c (gfc_init_kinds): Use PTRDIFF_TYPE instead of a signed int of size POINTER_SIZE for gfc_index_integer_kind. diff --git a/gcc/fortran/trans-types.c b/gcc/fortran/trans-types.c index d643c2e..f817a12 100644 --- a/gcc/fortran/trans-types.c +++ b/gcc/fortran/trans-types.c @@ -576,8 +576,8 @@ gfc_init_kinds (void) gfc_default_character_kind = gfc_character_kinds[0].kind; gfc_character_storage_size = gfc_default_character_kind * 8; - /* Choose the integer kind the same size as "void*" for our index kind. */ - gfc_index_integer_kind = POINTER_SIZE / 8; + gfc_index_integer_kind = get_int_kind_from_name (PTRDIFF_TYPE); + /* Pick a kind the same size as the C "int" type. */ gfc_c_int_kind = INT_TYPE_SIZE / 8;
Dear all, the front end uses for array indices (gfc_index_integer_kind / gfc_array_index_type) which is a signed integer of size POINTER_SIZE. The libgfortran library used to use typedef ssize_t index_type; which fails if sizeof(void*) is not sizeof(ssize_t); the latter is the case on LP64 systems (see PR). For 4.7 this was changed (in April 2011) to: typedef ptrdiff_t index_type; which makes more sense - and should be sufficient for LP64 systems. However, mixing an POINTER_SIZE type with ptrdiff_t only works if sizeof(ptrdiff_t) == POINTER_SIZE; in principle, the maximally allowed size of a variable can be smaller (e.g. page size) than the maximally allowed pointer size. (sizeof() returns a result of type size_t). I do not know whether such systems exist in practice and whether such a system is supported by GCC. The attached patch makes let's the FE emit code of the same data type as used in libgfortran - ptrdiff_t for the array indices. Build and regtested on x86-64-linux. OK for the trunk? Tobias