Hi!
As can be seen on the following testcase, instrument_mem_ref (for
both -fsanitize=alignment and -fsanitize=null) has been using wrong type
to find out what is the access type - instead of the type of MEM_REF
which is the access type it was using the TREE_TYPE of MEM_REF's argument
type, which can be some arbitrary other type, either due to type punning,
or if it is a SSA_NAME it can be random other type because most pointer
types are considered type compatible in GIMPLE.
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?
2015-04-09 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/65709
* ubsan.c (instrument_mem_ref): Use TREE_TYPE (base) instead of
TREE_TYPE (TREE_TYPE (t)).
* c-c++-common/ubsan/align-9.c: New test.
--- gcc/ubsan.c.jj 2015-03-27 10:48:33.000000000 +0100
+++ gcc/ubsan.c 2015-04-09 10:05:48.841221438 +0200
@@ -1232,9 +1232,9 @@ instrument_mem_ref (tree mem, tree base,
tree t = TREE_OPERAND (base, 0);
if (!POINTER_TYPE_P (TREE_TYPE (t)))
return;
- if (RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_TYPE (t))) && mem != base)
+ if (RECORD_OR_UNION_TYPE_P (TREE_TYPE (base)) && mem != base)
ikind = UBSAN_MEMBER_ACCESS;
- tree kind = build_int_cst (TREE_TYPE (t), ikind);
+ tree kind = build_int_cst (build_pointer_type (TREE_TYPE (base)), ikind);
tree alignt = build_int_cst (pointer_sized_int_node, align);
gcall *g = gimple_build_call_internal (IFN_UBSAN_NULL, 3, t, kind, alignt);
gimple_set_location (g, gimple_location (gsi_stmt (*iter)));
--- gcc/testsuite/c-c++-common/ubsan/align-9.c.jj 2015-04-09
10:11:15.227973011 +0200
+++ gcc/testsuite/c-c++-common/ubsan/align-9.c 2015-04-09 10:13:16.857017169
+0200
@@ -0,0 +1,21 @@
+/* Limit this to known non-strict alignment targets. */
+/* { dg-do run { target { i?86-*-linux* x86_64-*-linux* } } } */
+/* { dg-options "-O2 -fsanitize=alignment -fsanitize-recover=alignment" } */
+
+__attribute__((noinline, noclone)) void
+foo (void *p, const void *q)
+{
+ *(long int *) p = *(const long int *) q;
+}
+
+int
+main ()
+{
+ struct S { long c; char f[64]; char d; char e[2 * sizeof (long)]; char
g[64]; } s;
+ __builtin_memset (&s, '\0', sizeof s);
+ foo (&s.e[0], &s.e[sizeof (long)]);
+ return 0;
+}
+
+/* { dg-output "\.c:8:\[0-9]*: \[^\n\r]*load of misaligned address
0x\[0-9a-fA-F]* for type 'const long int', which requires \[48] byte
alignment.*" } */
+/* { dg-output "\.c:8:\[0-9]*: \[^\n\r]*store to misaligned address
0x\[0-9a-fA-F]* for type 'long int', which requires \[48] byte alignment" } */
Jakub
