diff options
Diffstat (limited to 'gcc/tree.cc')
| -rw-r--r-- | gcc/tree.cc | 45 |
1 files changed, 34 insertions, 11 deletions
diff --git a/gcc/tree.cc b/gcc/tree.cc index f8d24b5..c4ead94 100644 --- a/gcc/tree.cc +++ b/gcc/tree.cc @@ -12691,14 +12691,30 @@ array_ref_up_bound (tree exp) } /* Returns true if REF is an array reference, component reference, - or memory reference to an array at the end of a structure. - If this is the case, the array may be allocated larger - than its upper bound implies. */ + or memory reference to an array whose actual size might be larger + than its upper bound implies, there are multiple cases: + A. a ref to a flexible array member at the end of a structure; + B. a ref to an array with a different type against the original decl; + for example: + short a[16] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 }; + (*((char(*)[16])&a[0]))[i+8] + + C. a ref to an array that was passed as a parameter; + for example: + + int test (uint8_t *p, uint32_t t[1][1], int n) { + for (int i = 0; i < 4; i++, p++) + t[i][0] = ...; + + FIXME, the name of this routine need to be changed to be more accurate. */ bool array_at_struct_end_p (tree ref) { - tree atype; + /* the TYPE for this array referece. */ + tree atype = NULL_TREE; + /* the FIELD_DECL for the array field in the containing structure. */ + tree afield_decl = NULL_TREE; if (TREE_CODE (ref) == ARRAY_REF || TREE_CODE (ref) == ARRAY_RANGE_REF) @@ -12708,7 +12724,10 @@ array_at_struct_end_p (tree ref) } else if (TREE_CODE (ref) == COMPONENT_REF && TREE_CODE (TREE_TYPE (TREE_OPERAND (ref, 1))) == ARRAY_TYPE) - atype = TREE_TYPE (TREE_OPERAND (ref, 1)); + { + atype = TREE_TYPE (TREE_OPERAND (ref, 1)); + afield_decl = TREE_OPERAND (ref, 1); + } else if (TREE_CODE (ref) == MEM_REF) { tree arg = TREE_OPERAND (ref, 0); @@ -12720,6 +12739,7 @@ array_at_struct_end_p (tree ref) if (tree fld = last_field (argtype)) { atype = TREE_TYPE (fld); + afield_decl = fld; if (TREE_CODE (atype) != ARRAY_TYPE) return false; if (VAR_P (arg) && DECL_SIZE (fld)) @@ -12773,13 +12793,16 @@ array_at_struct_end_p (tree ref) ref = TREE_OPERAND (ref, 0); } - /* The array now is at struct end. Treat flexible arrays as + gcc_assert (!afield_decl + || (afield_decl && TREE_CODE (afield_decl) == FIELD_DECL)); + + /* The array now is at struct end. Treat flexible array member as always subject to extend, even into just padding constrained by an underlying decl. */ if (! TYPE_SIZE (atype) || ! TYPE_DOMAIN (atype) || ! TYPE_MAX_VALUE (TYPE_DOMAIN (atype))) - return true; + return afield_decl ? !DECL_NOT_FLEXARRAY (afield_decl) : true; /* If the reference is based on a declared entity, the size of the array is constrained by its given domain. (Do not trust commons PR/69368). */ @@ -12801,9 +12824,9 @@ array_at_struct_end_p (tree ref) if (TREE_CODE (TYPE_SIZE_UNIT (TREE_TYPE (atype))) != INTEGER_CST || TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (atype))) != INTEGER_CST || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (atype))) != INTEGER_CST) - return true; + return afield_decl ? !DECL_NOT_FLEXARRAY (afield_decl) : true; if (! get_addr_base_and_unit_offset (ref_to_array, &offset)) - return true; + return afield_decl ? !DECL_NOT_FLEXARRAY (afield_decl) : true; /* If at least one extra element fits it is a flexarray. */ if (known_le ((wi::to_offset (TYPE_MAX_VALUE (TYPE_DOMAIN (atype))) @@ -12811,12 +12834,12 @@ array_at_struct_end_p (tree ref) + 2) * wi::to_offset (TYPE_SIZE_UNIT (TREE_TYPE (atype))), wi::to_offset (DECL_SIZE_UNIT (ref)) - offset)) - return true; + return afield_decl ? !DECL_NOT_FLEXARRAY (afield_decl) : true; return false; } - return true; + return afield_decl ? !DECL_NOT_FLEXARRAY (afield_decl) : true; } /* Return a tree representing the offset, in bytes, of the field referenced |