On 05/14/2014 11:56 AM, Jakub Jelinek wrote:
On Tue, May 13, 2014 at 09:27:08PM +0200, Florian Weimer wrote:
Patterns that trigger the optimization and warning can form after
inlining, and it can be rather difficult to figure out what exactly
is causing the warning. The inlining context at least provides
additional hints, enabling developers to substitute the arguments
and discover what, precisely, is happening.
More context is provided with -g than without, but I think this is
acceptable.
I bootstrapped and tested the attached patch on
x86_64-redhat-linux-gnu, with no new regressions.
This looks wrong. If you want to print inline context, you just should
use %K%s and pass a tree with the right EXPR_LOCATION and TREE_BLOCK.
Oh, I didn't realize that %K prints the context recursively. Nice.
So perhaps:
if (stmt == NULL)
warning_at (input_location, OPT_Wstrict_overflow, "%s", warnmsg);
else
warning_at (gimple_location (stmt), OPT_Wstrict_overflow, "%K%s",
build_empty_stmt (gimple_location (stmt)), warnmsg);
(or add something similar to %K that will take location_t or change
%K to take location_t instead of tree now that we have both a block and
locus in location_t.
I looked at the existing %K users and all but one use expressions, so
the build_empty_stmt route seems to be most reasonable approach. Thanks
for the suggestion, new patch attached.
--
Florian Weimer / Red Hat Product Security Team
gcc/
2014-05-13 Florian Weimer <fwei...@redhat.com>
* fold-const.c (fold_undefer_overflow_warnings): Print inlining
information.
gcc/testsuite/
2014-05-13 Florian Weimer <fwei...@redhat.com>
* c-c++-common/Wstrict-overflow-1.c: New test.
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 0fcb87f..33fb629 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -233,7 +233,6 @@ void
fold_undefer_overflow_warnings (bool issue, const_gimple stmt, int code)
{
const char *warnmsg;
- location_t locus;
gcc_assert (fold_deferring_overflow_warnings > 0);
--fold_deferring_overflow_warnings;
@@ -264,10 +263,10 @@ fold_undefer_overflow_warnings (bool issue, const_gimple stmt, int code)
return;
if (stmt == NULL)
- locus = input_location;
+ warning_at (input_location, OPT_Wstrict_overflow, "%s", warnmsg);
else
- locus = gimple_location (stmt);
- warning_at (locus, OPT_Wstrict_overflow, "%s", warnmsg);
+ warning_at (gimple_location (stmt), OPT_Wstrict_overflow, "%K%s",
+ build_empty_stmt (gimple_location (stmt)), warnmsg);
}
/* Stop deferring overflow warnings, ignoring any deferred
diff --git a/gcc/testsuite/c-c++-common/Wstrict-overflow-1.c b/gcc/testsuite/c-c++-common/Wstrict-overflow-1.c
new file mode 100644
index 0000000..1624a33
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/Wstrict-overflow-1.c
@@ -0,0 +1,24 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -g -Wstrict-overflow" } */
+
+int f (void);
+
+static int g (int a, int b, int c)
+{
+ if (a + b < c) /* { dg-warning "assuming signed overflow" } */
+ return -1;
+ return f ();
+}
+
+static int h (int a, int b)
+{
+ return g(a, 1, b);
+}
+
+int k (int a)
+{
+ return h(a, a);
+}
+
+/* { dg-message "inlined from.*:15:" "inlined 15" { target *-*-* } 0 } */
+/* { dg-message "inlined from.*:20:" "inlined 20" { target *-*-* } 0 } */
