diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/cp/ChangeLog | 7 | ||||
| -rw-r--r-- | gcc/cp/class.c | 87 | ||||
| -rw-r--r-- | gcc/testsuite/g++.old-deja/g++.other/bitfld5.C | 7 |
3 files changed, 81 insertions, 20 deletions
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 79dc1c52ac4..892a466bd2e 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,10 @@ +2000-03-18 Mark Mitchell <mark@codesourcery.com> + + * class.c (check_bitfield_decl): Remove restriction on really long + bitfields. + (layout_class_type): Implement new ABI handling of bitfields + longer than their types. + 2000-03-18 Martin v. Löwis <loewis@informatik.hu-berlin.de> * parse.y (extdefs): Call ggc_collect. diff --git a/gcc/cp/class.c b/gcc/cp/class.c index 83ece59018b..5475ac4ba92 100644 --- a/gcc/cp/class.c +++ b/gcc/cp/class.c @@ -3658,17 +3658,6 @@ check_bitfield_decl (field) DECL_INITIAL (field) = NULL; cp_error_at ("zero width for bit-field `%D'", field); } - else if (0 < compare_tree_int (w, - TYPE_PRECISION - (long_long_unsigned_type_node))) - { - /* The backend will dump if you try to use something too - big; avoid that. */ - DECL_INITIAL (field) = NULL; - sorry ("bit-fields larger than %d bits", - TYPE_PRECISION (long_long_unsigned_type_node)); - cp_error_at (" in declaration of `%D'", field); - } else if (compare_tree_int (w, TYPE_PRECISION (type)) > 0 && TREE_CODE (type) != ENUMERAL_TYPE && TREE_CODE (type) != BOOLEAN_TYPE) @@ -4168,8 +4157,10 @@ dfs_search_base_offsets (binfo, data) non-static data member of the type indicated by RLI. BINFO is the binfo corresponding to the base subobject, or, if this is a non-static data-member, a dummy BINFO for the type of the data - member. V maps offsets to types already located at those offsets. - This function determines the position of the DECL. */ + member. BINFO may be NULL if checks to see if the field overlaps + an existing field with the same type are not required. V maps + offsets to types already located at those offsets. This function + determines the position of the DECL. */ static void layout_nonempty_base_or_field (rli, decl, binfo, v) @@ -4192,7 +4183,8 @@ layout_nonempty_base_or_field (rli, decl, binfo, v) BINFO_OFFSET. */ offset = size_int (CEIL (TREE_INT_CST_LOW (DECL_FIELD_BITPOS (decl)), BITS_PER_UNIT)); - propagate_binfo_offsets (binfo, offset); + if (binfo) + propagate_binfo_offsets (binfo, offset); /* We have to check to see whether or not there is already something of the same type at the offset we're about to use. @@ -4209,10 +4201,10 @@ layout_nonempty_base_or_field (rli, decl, binfo, v) empty class, have non-zero size, any overlap can happen only with a direct or indirect base-class -- it can't happen with a data member. */ - if (flag_new_abi && dfs_walk (binfo, - dfs_search_base_offsets, - dfs_skip_vbases, - v)) + if (binfo && flag_new_abi && dfs_walk (binfo, + dfs_search_base_offsets, + dfs_skip_vbases, + v)) { /* Undo the propogate_binfo_offsets call. */ offset = convert (sizetype, @@ -4930,6 +4922,8 @@ layout_class_type (t, empty_p, has_virtual_p, field = TREE_CHAIN (field)) { tree binfo; + tree type; + tree padding; /* We still pass things that aren't non-static data members to the back-end, in case it wants to do something with them. */ @@ -4939,11 +4933,64 @@ layout_class_type (t, empty_p, has_virtual_p, continue; } + type = TREE_TYPE (field); + + /* If this field is a bit-field whose width is greater than its + type, then there are some special rules for allocating it + under the new ABI. Under the old ABI, there were no special + rules, but the back-end can't handle bitfields longer than a + `long long', so we use the same mechanism. */ + if (DECL_C_BIT_FIELD (field) + && ((flag_new_abi + && INT_CST_LT (TYPE_SIZE (type), DECL_SIZE (field))) + || (!flag_new_abi + && compare_tree_int (DECL_SIZE (field), + TYPE_PRECISION + (long_long_unsigned_type_node)) > 0))) + { + integer_type_kind itk; + tree integer_type; + + /* We must allocate the bits as if suitably aligned for the + longest integer type that fits in this many bits. type + of the field. Then, we are supposed to use the left over + bits as additional padding. */ + for (itk = itk_char; itk != itk_none; ++itk) + if (INT_CST_LT (DECL_SIZE (field), + TYPE_SIZE (integer_types[itk]))) + break; + + /* ITK now indicates a type that is too large for the + field. We have to back up by one to find the largest + type that fits. */ + integer_type = integer_types[itk - 1]; + padding = size_diffop (DECL_SIZE (field), + TYPE_SIZE (integer_type)); + DECL_SIZE (field) = TYPE_SIZE (integer_type); + DECL_ALIGN (field) = TYPE_ALIGN (integer_type); + } + else + padding = NULL_TREE; + /* Create a dummy BINFO corresponding to this field. */ - binfo = make_binfo (size_zero_node, TREE_TYPE (field), - NULL_TREE, NULL_TREE); + binfo = make_binfo (size_zero_node, type, NULL_TREE, NULL_TREE); unshare_base_binfos (binfo); layout_nonempty_base_or_field (rli, field, binfo, v); + + /* If we needed additional padding after this field, add it + now. */ + if (padding) + { + tree padding_field; + + padding_field = build_decl (FIELD_DECL, + NULL_TREE, + char_type_node); + DECL_BIT_FIELD (padding_field) = 1; + DECL_SIZE (padding_field) = padding; + DECL_ALIGN (padding_field) = 1; + layout_nonempty_base_or_field (rli, padding_field, NULL_TREE, v); + } } /* Clean up. */ diff --git a/gcc/testsuite/g++.old-deja/g++.other/bitfld5.C b/gcc/testsuite/g++.old-deja/g++.other/bitfld5.C new file mode 100644 index 00000000000..a9e54ecbcd1 --- /dev/null +++ b/gcc/testsuite/g++.old-deja/g++.other/bitfld5.C @@ -0,0 +1,7 @@ +// Build don't link: +// Special g++ Options: -w + +struct S +{ + int i : 1756; +}; |