Richard or Jakub, could you please review this patch and see whether it's Okay to commit?
thanks a lot. Qing =================================== GCC extension accepts the case when a struct with a C99 flexible array member is embedded into another struct or union (possibly recursively) as the last field. __builtin_object_size should treat such struct as flexible size. gcc/c/ChangeLog: PR tree-optimization/101832 * c-decl.cc (finish_struct): Set TYPE_INCLUDES_FLEXARRAY for struct/union type. gcc/lto/ChangeLog: PR tree-optimization/101832 * lto-common.cc (compare_tree_sccs_1): Compare bit TYPE_NO_NAMED_ARGS_STDARG_P or TYPE_INCLUDES_FLEXARRAY properly for its corresponding type. gcc/ChangeLog: PR tree-optimization/101832 * print-tree.cc (print_node): Print new bit type_includes_flexarray. * tree-core.h (struct tree_type_common): Use bit no_named_args_stdarg_p as type_includes_flexarray for RECORD_TYPE or UNION_TYPE. * tree-object-size.cc (addr_object_size): Handle structure/union type when it has flexible size. * tree-streamer-in.cc (unpack_ts_type_common_value_fields): Stream in bit no_named_args_stdarg_p properly for its corresponding type. * tree-streamer-out.cc (pack_ts_type_common_value_fields): Stream out bit no_named_args_stdarg_p properly for its corresponding type. * tree.h (TYPE_INCLUDES_FLEXARRAY): New macro TYPE_INCLUDES_FLEXARRAY. gcc/testsuite/ChangeLog: PR tree-optimization/101832 * gcc.dg/builtin-object-size-pr101832.c: New test. change TYPE_INCLUDES_FLEXARRAY to TYPE_INCLUDES_FLEXARRAY --- gcc/c/c-decl.cc | 11 ++ gcc/lto/lto-common.cc | 5 +- gcc/print-tree.cc | 5 + .../gcc.dg/builtin-object-size-pr101832.c | 134 ++++++++++++++++++ gcc/tree-core.h | 2 + gcc/tree-object-size.cc | 23 ++- gcc/tree-streamer-in.cc | 5 +- gcc/tree-streamer-out.cc | 5 +- gcc/tree.h | 7 +- 9 files changed, 192 insertions(+), 5 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/builtin-object-size-pr101832.c diff --git a/gcc/c/c-decl.cc b/gcc/c/c-decl.cc index b5b491cf2da..0c718151f6d 100644 --- a/gcc/c/c-decl.cc +++ b/gcc/c/c-decl.cc @@ -9282,6 +9282,17 @@ finish_struct (location_t loc, tree t, tree fieldlist, tree attributes, /* Set DECL_NOT_FLEXARRAY flag for FIELD_DECL x. */ DECL_NOT_FLEXARRAY (x) = !is_flexible_array_member_p (is_last_field, x); + /* Set TYPE_INCLUDES_FLEXARRAY for the context of x, t. + when x is an array and is the last field. */ + if (TREE_CODE (TREE_TYPE (x)) == ARRAY_TYPE) + TYPE_INCLUDES_FLEXARRAY (t) + = is_last_field && flexible_array_member_type_p (TREE_TYPE (x)); + /* Recursively set TYPE_INCLUDES_FLEXARRAY for the context of x, t + when x is an union or record and is the last field. */ + else if (RECORD_OR_UNION_TYPE_P (TREE_TYPE (x))) + TYPE_INCLUDES_FLEXARRAY (t) + = is_last_field && TYPE_INCLUDES_FLEXARRAY (TREE_TYPE (x)); + if (DECL_NAME (x) || RECORD_OR_UNION_TYPE_P (TREE_TYPE (x))) saw_named_field = true; diff --git a/gcc/lto/lto-common.cc b/gcc/lto/lto-common.cc index 537570204b3..f6b85bbc6f7 100644 --- a/gcc/lto/lto-common.cc +++ b/gcc/lto/lto-common.cc @@ -1275,7 +1275,10 @@ compare_tree_sccs_1 (tree t1, tree t2, tree **map) if (AGGREGATE_TYPE_P (t1)) compare_values (TYPE_TYPELESS_STORAGE); compare_values (TYPE_EMPTY_P); - compare_values (TYPE_NO_NAMED_ARGS_STDARG_P); + if (FUNC_OR_METHOD_TYPE_P (t1)) + compare_values (TYPE_NO_NAMED_ARGS_STDARG_P); + if (RECORD_OR_UNION_TYPE_P (t1)) + compare_values (TYPE_INCLUDES_FLEXARRAY); compare_values (TYPE_PACKED); compare_values (TYPE_RESTRICT); compare_values (TYPE_USER_ALIGN); diff --git a/gcc/print-tree.cc b/gcc/print-tree.cc index ccecd3dc6a7..62451b6cf4e 100644 --- a/gcc/print-tree.cc +++ b/gcc/print-tree.cc @@ -632,6 +632,11 @@ print_node (FILE *file, const char *prefix, tree node, int indent, && TYPE_CXX_ODR_P (node)) fputs (" cxx-odr-p", file); + if ((code == RECORD_TYPE + || code == UNION_TYPE) + && TYPE_INCLUDES_FLEXARRAY (node)) + fputs (" includes-flexarray", file); + /* The transparent-union flag is used for different things in different nodes. */ if ((code == UNION_TYPE || code == RECORD_TYPE) diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-pr101832.c b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832.c new file mode 100644 index 00000000000..60078e11634 --- /dev/null +++ b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832.c @@ -0,0 +1,134 @@ +/* PR 101832: + GCC extension accepts the case when a struct with a C99 flexible array + member is embedded into another struct (possibly recursively). + __builtin_object_size will treat such struct as flexible size. + However, when a structure with non-C99 flexible array member, i.e, trailing + [0], [1], or [4], is embedded into anther struct, the stucture will not + be treated as flexible size. */ +/* { dg-do run } */ +/* { dg-options "-O2" } */ + +#include "builtin-object-size-common.h" + +#define expect(p, _v) do { \ + size_t v = _v; \ + if (p == v) \ + __builtin_printf ("ok: %s == %zd\n", #p, p); \ + else {\ + __builtin_printf ("WAT: %s == %zd (expected %zd)\n", #p, p, v); \ + FAIL (); \ + } \ +} while (0); + + +struct A { + int n; + char data[]; +}; + +struct B { + int m; + struct A a; +}; + +struct C { + int q; + struct B b; +}; + +struct A0 { + int n; + char data[0]; +}; + +struct B0 { + int m; + struct A0 a; +}; + +struct C0 { + int q; + struct B0 b; +}; + +struct A1 { + int n; + char data[1]; +}; + +struct B1 { + int m; + struct A1 a; +}; + +struct C1 { + int q; + struct B1 b; +}; + +struct An { + int n; + char data[8]; +}; + +struct Bn { + int m; + struct An a; +}; + +struct Cn { + int q; + struct Bn b; +}; + +volatile void *magic1, *magic2; + +int main (int argc, char *argv[]) +{ + struct B *outer; + struct C *outest; + + /* Make sure optimization can't find some other object size. */ + outer = (void *)magic1; + outest = (void *)magic2; + + expect (__builtin_object_size (&outer->a, 1), -1); + expect (__builtin_object_size (&outest->b, 1), -1); + expect (__builtin_object_size (&outest->b.a, 1), -1); + + struct B0 *outer0; + struct C0 *outest0; + + /* Make sure optimization can't find some other object size. */ + outer0 = (void *)magic1; + outest0 = (void *)magic2; + + expect (__builtin_object_size (&outer0->a, 1), sizeof (outer0->a)); + expect (__builtin_object_size (&outest0->b, 1), sizeof (outest0->b)); + expect (__builtin_object_size (&outest0->b.a, 1), sizeof (outest0->b.a)); + + struct B1 *outer1; + struct C1 *outest1; + + /* Make sure optimization can't find some other object size. */ + outer1 = (void *)magic1; + outest1 = (void *)magic2; + + expect (__builtin_object_size (&outer1->a, 1), sizeof (outer1->a)); + expect (__builtin_object_size (&outest1->b, 1), sizeof (outest1->b)); + expect (__builtin_object_size (&outest1->b.a, 1), sizeof (outest1->b.a)); + + struct Bn *outern; + struct Cn *outestn; + + /* Make sure optimization can't find some other object size. */ + outern = (void *)magic1; + outestn = (void *)magic2; + + expect (__builtin_object_size (&outern->a, 1), sizeof (outern->a)); + expect (__builtin_object_size (&outestn->b, 1), sizeof (outestn->b)); + expect (__builtin_object_size (&outestn->b.a, 1), sizeof (outestn->b.a)); + + DONE (); + return 0; +} diff --git a/gcc/tree-core.h b/gcc/tree-core.h index 9d44c04bf03..b2f619c5efc 100644 --- a/gcc/tree-core.h +++ b/gcc/tree-core.h @@ -1712,6 +1712,8 @@ struct GTY(()) tree_type_common { unsigned typeless_storage : 1; unsigned empty_flag : 1; unsigned indivisible_p : 1; + /* TYPE_NO_NAMED_ARGS_STDARG_P for a stdarg function. + Or TYPE_INCLUDES_FLEXARRAY for RECORD_TYPE and UNION_TYPE. */ unsigned no_named_args_stdarg_p : 1; unsigned spare : 1; diff --git a/gcc/tree-object-size.cc b/gcc/tree-object-size.cc index 9a936a91983..a62af050056 100644 --- a/gcc/tree-object-size.cc +++ b/gcc/tree-object-size.cc @@ -633,11 +633,32 @@ addr_object_size (struct object_size_info *osi, const_tree ptr, v = NULL_TREE; break; case COMPONENT_REF: - if (TREE_CODE (TREE_TYPE (v)) != ARRAY_TYPE) + /* When the ref is not to an aggregate type, i.e, an array, + a record or a union, it will not have flexible size, + compute the object size directly. */ + if (!AGGREGATE_TYPE_P (TREE_TYPE (v))) { v = NULL_TREE; break; } + /* if the ref is to a record or union type, but the type + does not include a flexible array recursively, compute + the object size directly. */ + if (RECORD_OR_UNION_TYPE_P (TREE_TYPE (v))) + { + if (!TYPE_INCLUDES_FLEXARRAY (TREE_TYPE (v))) + { + v = NULL_TREE; + break; + } + else + { + v = TREE_OPERAND (v, 0); + break; + } + } + /* Now the ref is to an array type. */ + gcc_assert (TREE_CODE (TREE_TYPE (v)) == ARRAY_TYPE); is_flexible_array_mem_ref = array_ref_flexible_size_p (v); while (v != pt_var && TREE_CODE (v) == COMPONENT_REF) if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) diff --git a/gcc/tree-streamer-in.cc b/gcc/tree-streamer-in.cc index c803800862c..be2bdbb7699 100644 --- a/gcc/tree-streamer-in.cc +++ b/gcc/tree-streamer-in.cc @@ -386,7 +386,10 @@ unpack_ts_type_common_value_fields (struct bitpack_d *bp, tree expr) if (AGGREGATE_TYPE_P (expr)) TYPE_TYPELESS_STORAGE (expr) = (unsigned) bp_unpack_value (bp, 1); TYPE_EMPTY_P (expr) = (unsigned) bp_unpack_value (bp, 1); - TYPE_NO_NAMED_ARGS_STDARG_P (expr) = (unsigned) bp_unpack_value (bp, 1); + if (FUNC_OR_METHOD_TYPE_P (expr)) + TYPE_NO_NAMED_ARGS_STDARG_P (expr) = (unsigned) bp_unpack_value (bp, 1); + if (RECORD_OR_UNION_TYPE_P (expr)) + TYPE_INCLUDES_FLEXARRAY (expr) = (unsigned) bp_unpack_value (bp, 1); TYPE_PRECISION (expr) = bp_unpack_var_len_unsigned (bp); SET_TYPE_ALIGN (expr, bp_unpack_var_len_unsigned (bp)); #ifdef ACCEL_COMPILER diff --git a/gcc/tree-streamer-out.cc b/gcc/tree-streamer-out.cc index 5751f77273b..6d4a9d90da6 100644 --- a/gcc/tree-streamer-out.cc +++ b/gcc/tree-streamer-out.cc @@ -355,7 +355,10 @@ pack_ts_type_common_value_fields (struct bitpack_d *bp, tree expr) if (AGGREGATE_TYPE_P (expr)) bp_pack_value (bp, TYPE_TYPELESS_STORAGE (expr), 1); bp_pack_value (bp, TYPE_EMPTY_P (expr), 1); - bp_pack_value (bp, TYPE_NO_NAMED_ARGS_STDARG_P (expr), 1); + if (FUNC_OR_METHOD_TYPE_P (expr)) + bp_pack_value (bp, TYPE_NO_NAMED_ARGS_STDARG_P (expr), 1); + if (RECORD_OR_UNION_TYPE_P (expr)) + bp_pack_value (bp, TYPE_INCLUDES_FLEXARRAY (expr), 1); bp_pack_var_len_unsigned (bp, TYPE_PRECISION (expr)); bp_pack_var_len_unsigned (bp, TYPE_ALIGN (expr)); } diff --git a/gcc/tree.h b/gcc/tree.h index 0b72663e6a1..d4755317a4c 100644 --- a/gcc/tree.h +++ b/gcc/tree.h @@ -786,7 +786,12 @@ extern void omp_clause_range_check_failed (const_tree, const char *, int, (...) prototype, where arguments can be accessed with va_start and va_arg), as opposed to an unprototyped function. */ #define TYPE_NO_NAMED_ARGS_STDARG_P(NODE) \ - (TYPE_CHECK (NODE)->type_common.no_named_args_stdarg_p) + (FUNC_OR_METHOD_CHECK (NODE)->type_common.no_named_args_stdarg_p) + +/* True if this RECORD_TYPE or UNION_TYPE includes a flexible array member + as the last field recursively. */ +#define TYPE_INCLUDES_FLEXARRAY(NODE) \ + (RECORD_OR_UNION_CHECK (NODE)->type_common.no_named_args_stdarg_p) /* In an IDENTIFIER_NODE, this means that assemble_name was called with this string as an argument. */ -- 2.31.1