diff options
Diffstat (limited to 'gcc/c-decl.c')
| -rw-r--r-- | gcc/c-decl.c | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/gcc/c-decl.c b/gcc/c-decl.c index 7af70f0..3cb29c0 100644 --- a/gcc/c-decl.c +++ b/gcc/c-decl.c @@ -3707,6 +3707,17 @@ shadow_tag_warned (const struct c_declspecs *declspecs, int warned) warned = 1; pending_xref_error (); } + else if (declspecs->typespec_kind != ctsk_tagdef + && declspecs->typespec_kind != ctsk_tagfirstref + && declspecs->alignas_p) + { + if (warned != 1) + pedwarn (input_location, 0, + "empty declaration with %<_Alignas%> " + "does not redeclare tag"); + warned = 1; + pending_xref_error (); + } else { pending_invalid_xref = 0; @@ -3782,6 +3793,12 @@ shadow_tag_warned (const struct c_declspecs *declspecs, int warned) warned = 2; } + if (!warned && !in_system_header && declspecs->alignas_p) + { + warning (0, "useless %<_Alignas%> in empty declaration"); + warned = 2; + } + if (warned != 1) { if (!found_tag) @@ -4894,6 +4911,7 @@ grokdeclarator (const struct c_declarator *declarator, tree expr_dummy; bool expr_const_operands_dummy; enum c_declarator_kind first_non_attr_kind; + unsigned int alignas_align = 0; if (TREE_CODE (type) == ERROR_MARK) return error_mark_node; @@ -5737,6 +5755,46 @@ grokdeclarator (const struct c_declarator *declarator, if (bitfield) check_bitfield_type_and_width (&type, width, name); + /* Reject invalid uses of _Alignas. */ + if (declspecs->alignas_p) + { + if (storage_class == csc_typedef) + error_at (loc, "alignment specified for typedef %qE", name); + else if (storage_class == csc_register) + error_at (loc, "alignment specified for %<register%> object %qE", + name); + else if (decl_context == PARM) + { + if (name) + error_at (loc, "alignment specified for parameter %qE", name); + else + error_at (loc, "alignment specified for unnamed parameter"); + } + else if (bitfield) + { + if (name) + error_at (loc, "alignment specified for bit-field %qE", name); + else + error_at (loc, "alignment specified for unnamed bit-field"); + } + else if (TREE_CODE (type) == FUNCTION_TYPE) + error_at (loc, "alignment specified for function %qE", name); + else if (declspecs->align_log != -1) + { + alignas_align = 1U << declspecs->align_log; + if (alignas_align < TYPE_ALIGN_UNIT (type)) + { + if (name) + error_at (loc, "%<_Alignas%> specifiers cannot reduce " + "alignment of %qE", name); + else + error_at (loc, "%<_Alignas%> specifiers cannot reduce " + "alignment of unnamed field"); + alignas_align = 0; + } + } + } + /* Did array size calculations overflow? */ if (TREE_CODE (type) == ARRAY_TYPE @@ -6117,6 +6175,13 @@ grokdeclarator (const struct c_declarator *declarator, /* Record constancy and volatility. */ c_apply_type_quals_to_decl (type_quals, decl); + /* Apply _Alignas specifiers. */ + if (alignas_align) + { + DECL_ALIGN (decl) = alignas_align * BITS_PER_UNIT; + DECL_USER_ALIGN (decl) = 1; + } + /* If a type has volatile components, it should be stored in memory. Otherwise, the fact that those components are volatile will be ignored, and would even crash the compiler. @@ -8709,6 +8774,7 @@ build_null_declspecs (void) ret->expr = 0; ret->decl_attr = 0; ret->attrs = 0; + ret->align_log = -1; ret->typespec_word = cts_none; ret->storage_class = csc_none; ret->expr_const_operands = true; @@ -8732,6 +8798,7 @@ build_null_declspecs (void) ret->volatile_p = false; ret->restrict_p = false; ret->saturating_p = false; + ret->alignas_p = false; ret->address_space = ADDR_SPACE_GENERIC; return ret; } @@ -9522,6 +9589,22 @@ declspecs_add_attrs (struct c_declspecs *specs, tree attrs) return specs; } +/* Add an _Alignas specifier (expression ALIGN, or type whose + alignment is ALIGN) to the declaration specifiers SPECS, returning + SPECS. */ +struct c_declspecs * +declspecs_add_alignas (struct c_declspecs *specs, tree align) +{ + int align_log; + specs->alignas_p = true; + if (align == error_mark_node) + return specs; + align_log = check_user_alignment (align, true); + if (align_log > specs->align_log) + specs->align_log = align_log; + return specs; +} + /* Combine "long", "short", "signed", "unsigned" and "_Complex" type specifiers with any other type specifier to determine the resulting type. This is where ISO C checks on complex types are made, since |