Handle hints provided by __attribute__ ((access (...))) to compute
dynamic sizes for objects.
gcc/ChangeLog:
* tree-object-size.c: Include tree-dfa.h.
(parm_object_size): New function.
(collect_object_sizes_for): Call it.
gcc/testsuite/ChangeLog:
* gcc.dg/builtin-dynamic-object-size-0.c (test_parmsz_simple):
New function.
(main): Call it.
Signed-off-by: Siddhesh Poyarekar <siddhesh@gotplt.org>
---
.../gcc.dg/builtin-dynamic-object-size-0.c | 10 ++++
gcc/tree-object-size.c | 55 ++++++++++++++++++-
2 files changed, 64 insertions(+), 1 deletion(-)
@@ -46,6 +46,13 @@ test_deploop (size_t sz, size_t cond)
return __builtin_dynamic_object_size (bin, 0);
}
+size_t
+__attribute__ ((access (__read_write__, 1, 2)))
+test_parmsz_simple (void *obj, size_t sz)
+{
+ return __builtin_dynamic_object_size (obj, 0);
+}
+
unsigned nfails = 0;
#define FAIL() ({ \
@@ -64,6 +71,9 @@ main (int argc, char **argv)
FAIL ();
if (test_deploop (128, 129) != 32)
FAIL ();
+ if (test_parmsz_simple (argv[0], __builtin_strlen (argv[0]) + 1)
+ != __builtin_strlen (argv[0]) + 1)
+ FAIL ();
if (nfails > 0)
__builtin_abort ();
@@ -32,6 +32,7 @@ along with GCC; see the file COPYING3. If not see
#include "gimple-fold.h"
#include "gimple-iterator.h"
#include "tree-cfg.h"
+#include "tree-dfa.h"
#include "stringpool.h"
#include "attribs.h"
#include "builtins.h"
@@ -1373,6 +1374,58 @@ phi_dynamic_object_size (struct object_size_info *osi, tree var)
return res;
}
+/* Find size of an object passed as a parameter to the function. */
+
+static tree
+parm_object_size (struct object_size_info *osi, tree var)
+{
+ int object_size_type = osi->object_size_type;
+ tree parm = SSA_NAME_VAR (var);
+
+ if (dump_file)
+ {
+ fprintf (dump_file, "Object is a parameter: ");
+ print_generic_expr (dump_file, parm, dump_flags);
+ fprintf (dump_file, " which is %s a pointer type\n",
+ POINTER_TYPE_P (TREE_TYPE (parm)) ? "" : "not");
+ }
+
+ if (!(object_size_type & OST_DYNAMIC) || !POINTER_TYPE_P (TREE_TYPE (parm)))
+ return expr_object_size (osi, parm);
+
+ /* Look for access attribute. */
+ rdwr_map rdwr_idx;
+
+ tree fndecl = cfun->decl;
+ const attr_access *access = get_parm_access (rdwr_idx, parm, fndecl);
+ tree typesize = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (parm)));
+
+ if (access && access->sizarg != UINT_MAX)
+ {
+ tree fnargs = DECL_ARGUMENTS (fndecl);
+ tree arg = NULL_TREE;
+ unsigned argpos = 0;
+
+ /* Walk through the parameters to pick the size parameter and safely
+ scale it by the type size. */
+ for (arg = fnargs; argpos != access->sizarg && arg;
+ arg = TREE_CHAIN (arg), ++argpos);
+
+ if (arg != NULL_TREE && INTEGRAL_TYPE_P (TREE_TYPE (arg)))
+ {
+ tree sz = get_or_create_ssa_default_def (cfun, arg);
+ if (sz != NULL_TREE)
+ {
+ sz = fold_convert (sizetype, sz);
+ if (typesize)
+ sz = size_binop (MULT_EXPR, sz, typesize);
+ return sz;
+ }
+ }
+ }
+ return size_unknown (object_size_type);
+}
+
/* Compute object sizes for VAR.
For ADDR_EXPR an object size is the number of remaining bytes
to the end of the object (where what is considered an object depends on
@@ -1483,7 +1536,7 @@ collect_object_sizes_for (struct object_size_info *osi, tree var)
case GIMPLE_NOP:
if (SSA_NAME_VAR (var)
&& TREE_CODE (SSA_NAME_VAR (var)) == PARM_DECL)
- res = expr_object_size (osi, SSA_NAME_VAR (var));
+ res = parm_object_size (osi, var);
else
/* Uninitialized SSA names point nowhere. */
res = size_unknown (object_size_type);