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 | 11 ++++
gcc/tree-object-size.c | 50 ++++++++++++++++++-
2 files changed, 60 insertions(+), 1 deletion(-)
@@ -46,6 +46,14 @@ test_deploop (size_t sz, size_t cond)
return __builtin_dynamic_object_size (bin, 0);
}
+size_t
+__attribute__ ((access (__read_write__, 1, 2)))
+__attribute__ ((noinline))
+test_parmsz_simple (void *obj, size_t sz)
+{
+ return __builtin_dynamic_object_size (obj, 0);
+}
+
unsigned nfails = 0;
#define FAIL() ({ \
@@ -64,6 +72,9 @@ 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"
@@ -1446,6 +1447,53 @@ cond_expr_object_size (struct object_size_info *osi, tree var, gimple *stmt)
return reexamine;
}
+/* Find size of an object passed as a parameter to the function. */
+
+static void
+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 (!(object_size_type & OST_DYNAMIC) || !POINTER_TYPE_P (TREE_TYPE (parm)))
+ expr_object_size (osi, var, 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)));
+ tree sz = NULL_TREE;
+
+ 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)))
+ {
+ 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);
+ }
+ }
+ }
+ if (!sz)
+ sz = size_unknown (object_size_type);
+
+ object_sizes_set (osi, SSA_NAME_VERSION (var), sz, sz);
+}
+
/* Compute an object size expression for VAR, which is the result of a PHI
node. */
@@ -1603,7 +1651,7 @@ 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)
- expr_object_size (osi, var, SSA_NAME_VAR (var));
+ parm_object_size (osi, var);
else
/* Uninitialized SSA names point nowhere. */
unknown_object_size (osi, var);