Hi!
Another problem from the compiler side when working on the asan testsuite
is that at higher -O* levels the __asan_report_* noreturn calls are
cross-jumped, but the library relies on their locus to print accurrate
locations when symbolized. Without it, asan might report an error
completely elsewhere in a function.
This patch disables cross-jumping of such builtins.
Alternatively, I could introduce some attribute (no_cross_jump?),
ECF_NO_CROSS_JUMP, add those attributes to those builtins (and let users
add those too to functions they wish), and look at ECF_NO_CROSS_JUMP instead
during cross-jumping.
2012-12-05 Jakub Jelinek <ja...@redhat.com>
* sanitizer.def: Add comment about importance of ordering of
BUILT_IN_ASAN_REPORT* builtins.
* cfgcleanup.c (old_insns_match_p): Don't cross-jump __asan_report_*
builtins.
--- gcc/sanitizer.def.jj 2012-12-04 14:19:36.000000000 +0100
+++ gcc/sanitizer.def 2012-12-05 09:38:01.205958515 +0100
@@ -29,6 +29,8 @@ along with GCC; see the file COPYING3.
/* Address Sanitizer */
DEF_SANITIZER_BUILTIN(BUILT_IN_ASAN_INIT, "__asan_init",
BT_FN_VOID, ATTR_NOTHROW_LEAF_LIST)
+/* Do not reorder the BUILT_IN_ASAN_REPORT* builtins, e.g. cfgcleanup.c
+ relies on this order. */
DEF_SANITIZER_BUILTIN(BUILT_IN_ASAN_REPORT_LOAD1, "__asan_report_load1",
BT_FN_VOID_PTR, ATTR_NORETURN_NOTHROW_LEAF_LIST)
DEF_SANITIZER_BUILTIN(BUILT_IN_ASAN_REPORT_LOAD2, "__asan_report_load2",
--- gcc/cfgcleanup.c.jj 2012-11-20 09:37:47.000000000 +0100
+++ gcc/cfgcleanup.c 2012-12-05 09:37:23.389181984 +0100
@@ -1138,6 +1138,28 @@ old_insns_match_p (int mode ATTRIBUTE_UN
CALL_INSN_FUNCTION_USAGE (i2))
|| SIBLING_CALL_P (i1) != SIBLING_CALL_P (i2))
return dir_none;
+
+ /* For address sanitizer, never crossjump __asan_report_* builtins,
+ otherwise errors might be reported on incorrect lines. */
+ if (flag_asan)
+ {
+ rtx call = get_call_rtx_from (i1);
+ if (call && GET_CODE (XEXP (XEXP (call, 0), 0)) == SYMBOL_REF)
+ {
+ rtx symbol = XEXP (XEXP (call, 0), 0);
+ if (SYMBOL_REF_DECL (symbol)
+ && TREE_CODE (SYMBOL_REF_DECL (symbol)) == FUNCTION_DECL)
+ {
+ if ((DECL_BUILT_IN_CLASS (SYMBOL_REF_DECL (symbol))
+ == BUILT_IN_NORMAL)
+ && DECL_FUNCTION_CODE (SYMBOL_REF_DECL (symbol))
+ >= BUILT_IN_ASAN_REPORT_LOAD1
+ && DECL_FUNCTION_CODE (SYMBOL_REF_DECL (symbol))
+ <= BUILT_IN_ASAN_REPORT_STORE16)
+ return dir_none;
+ }
+ }
+ }
}
#ifdef STACK_REGS
Jakub
