diff options
Diffstat (limited to 'gcc/c/c-decl.cc')
| -rw-r--r-- | gcc/c/c-decl.cc | 130 |
1 files changed, 121 insertions, 9 deletions
diff --git a/gcc/c/c-decl.cc b/gcc/c/c-decl.cc index ffa63dc..193e268 100644 --- a/gcc/c/c-decl.cc +++ b/gcc/c/c-decl.cc @@ -5034,6 +5034,41 @@ set_array_declarator_inner (struct c_declarator *decl, return decl; } +/* Determine whether TYPE is a ISO C99 flexible array memeber type "[]". */ +static bool +flexible_array_member_type_p (const_tree type) +{ + if (TREE_CODE (type) == ARRAY_TYPE + && TYPE_SIZE (type) == NULL_TREE + && TYPE_DOMAIN (type) != NULL_TREE + && TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL_TREE) + return true; + + return false; +} + +/* Determine whether TYPE is a one-element array type "[1]". */ +static bool +one_element_array_type_p (const_tree type) +{ + if (TREE_CODE (type) != ARRAY_TYPE) + return false; + return integer_zerop (array_type_nelts (type)); +} + +/* Determine whether TYPE is a zero-length array type "[0]". */ +static bool +zero_length_array_type_p (const_tree type) +{ + if (TREE_CODE (type) == ARRAY_TYPE) + if (tree type_size = TYPE_SIZE_UNIT (type)) + if ((integer_zerop (type_size)) + && TYPE_DOMAIN (type) != NULL_TREE + && TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL_TREE) + return true; + return false; +} + /* INIT is a constructor that forms DECL's initializer. If the final element initializes a flexible array field, add the size of that initializer to DECL's size. */ @@ -5048,10 +5083,7 @@ add_flexible_array_elts_to_size (tree decl, tree init) elt = CONSTRUCTOR_ELTS (init)->last ().value; type = TREE_TYPE (elt); - if (TREE_CODE (type) == ARRAY_TYPE - && TYPE_SIZE (type) == NULL_TREE - && TYPE_DOMAIN (type) != NULL_TREE - && TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL_TREE) + if (flexible_array_member_type_p (type)) { complete_array_type (&type, elt, false); DECL_SIZE (decl) @@ -8755,6 +8787,81 @@ finish_incomplete_vars (tree incomplete_vars, bool toplevel) } } + +/* Determine whether the FIELD_DECL X is a flexible array member according to + the following info: + A. whether the FIELD_DECL X is the last field of the DECL_CONTEXT; + B. whether the FIELD_DECL is an array that is declared as "[]", "[0]", + or "[1]"; + C. flag_strict_flex_arrays; + D. the attribute strict_flex_array that is attached to the field + if presenting. + Return TRUE when it's a flexible array member, FALSE otherwise. */ + +static bool +is_flexible_array_member_p (bool is_last_field, + tree x) +{ + /* If not the last field, return false. */ + if (!is_last_field) + return false; + + /* If not an array field, return false. */ + if (TREE_CODE (TREE_TYPE (x)) != ARRAY_TYPE) + return false; + + bool is_zero_length_array = zero_length_array_type_p (TREE_TYPE (x)); + bool is_one_element_array = one_element_array_type_p (TREE_TYPE (x)); + bool is_flexible_array = flexible_array_member_type_p (TREE_TYPE (x)); + + unsigned int strict_flex_array_level = flag_strict_flex_arrays; + + tree attr_strict_flex_array = lookup_attribute ("strict_flex_array", + DECL_ATTRIBUTES (x)); + /* If there is a strict_flex_array attribute attached to the field, + override the flag_strict_flex_arrays. */ + if (attr_strict_flex_array) + { + /* Get the value of the level first from the attribute. */ + unsigned HOST_WIDE_INT attr_strict_flex_array_level = 0; + gcc_assert (TREE_VALUE (attr_strict_flex_array) != NULL_TREE); + attr_strict_flex_array = TREE_VALUE (attr_strict_flex_array); + gcc_assert (TREE_VALUE (attr_strict_flex_array) != NULL_TREE); + attr_strict_flex_array = TREE_VALUE (attr_strict_flex_array); + gcc_assert (tree_fits_uhwi_p (attr_strict_flex_array)); + attr_strict_flex_array_level = tree_to_uhwi (attr_strict_flex_array); + + /* The attribute has higher priority than flag_struct_flex_array. */ + strict_flex_array_level = attr_strict_flex_array_level; + } + + switch (strict_flex_array_level) + { + case 0: + /* Default, all trailing arrays are flexible array members. */ + return true; + case 1: + /* Level 1: all "[1]", "[0]", and "[]" are flexible array members. */ + if (is_one_element_array) + return true; + /* FALLTHROUGH. */ + case 2: + /* Level 2: all "[0]", and "[]" are flexible array members. */ + if (is_zero_length_array) + return true; + /* FALLTHROUGH. */ + case 3: + /* Level 3: Only "[]" are flexible array members. */ + if (is_flexible_array) + return true; + break; + default: + gcc_unreachable (); + } + return false; +} + + /* Fill in the fields of a RECORD_TYPE or UNION_TYPE node, T. LOC is the location of the RECORD_TYPE or UNION_TYPE's definition. FIELDLIST is a chain of FIELD_DECL nodes for the fields. @@ -8816,6 +8923,11 @@ finish_struct (location_t loc, tree t, tree fieldlist, tree attributes, bool saw_named_field = false; for (x = fieldlist; x; x = DECL_CHAIN (x)) { + /* Whether this field is the last field of the structure or union. + for UNION, any field is the last field of it. */ + bool is_last_field = (DECL_CHAIN (x) == NULL_TREE) + || (TREE_CODE (t) == UNION_TYPE); + if (TREE_TYPE (x) == error_mark_node) continue; @@ -8854,10 +8966,7 @@ finish_struct (location_t loc, tree t, tree fieldlist, tree attributes, DECL_PACKED (x) = 1; /* Detect flexible array member in an invalid context. */ - if (TREE_CODE (TREE_TYPE (x)) == ARRAY_TYPE - && TYPE_SIZE (TREE_TYPE (x)) == NULL_TREE - && TYPE_DOMAIN (TREE_TYPE (x)) != NULL_TREE - && TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (x))) == NULL_TREE) + if (flexible_array_member_type_p (TREE_TYPE (x))) { if (TREE_CODE (t) == UNION_TYPE) { @@ -8865,7 +8974,7 @@ finish_struct (location_t loc, tree t, tree fieldlist, tree attributes, "flexible array member in union"); TREE_TYPE (x) = error_mark_node; } - else if (DECL_CHAIN (x) != NULL_TREE) + else if (!is_last_field) { error_at (DECL_SOURCE_LOCATION (x), "flexible array member not at end of struct"); @@ -8885,6 +8994,9 @@ finish_struct (location_t loc, tree t, tree fieldlist, tree attributes, pedwarn (DECL_SOURCE_LOCATION (x), OPT_Wpedantic, "invalid use of structure with flexible array member"); + /* Set DECL_NOT_FLEXARRAY flag for FIELD_DECL x. */ + DECL_NOT_FLEXARRAY (x) = !is_flexible_array_member_p (is_last_field, x); + if (DECL_NAME (x) || RECORD_OR_UNION_TYPE_P (TREE_TYPE (x))) saw_named_field = true; |