http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60014
Bug ID: 60014
Summary: Bad warning suppression
Product: gcc
Version: 4.8.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: megahallon at gmail dot com
Using gcc 4.8.2:
/tmp/foo/foo.h:
-------------------------------
#define FOO(a, b) __LINE__;
-------------------------------
bug.c:
-------------------------------
#include "foo.h"
int main()
{
FOO(1,
0);
char* a = 1;
}
-------------------------------
$ /usr/bin/gcc bug.c -isystem /tmp/foo -no-integrated-cpp
should give a warning on line 7 but it not seen.
These works:
$ /usr/bin/gcc bug.c -isystem /tmp/foo -no-integrated-cpp
-ftrack-macro-expansion=0
$ /usr/bin/gcc bug.c -I /tmp/foo -no-integrated-cpp
$ /usr/bin/gcc bug.c -isystem /tmp/foo
-save-temps gives the same results as -no-integrated-cpp.
Output from -save-temps:
bug.i
-----------------------------
void main()
{
6
# 5 "bug.c" 3 4
;
;
char *a = 1;
}
-----------------------------
The suppress flag in the line directive apparently affects line 7 which is not
as expected.
In practice this means that ccache and similar systems that compiles
preprocessed output may fail to show warnings that are seen when compiling
normally.
