walkert@zaphod:foo$ cat bar.C template<class T> struct X { struct Y { T t; }; X( ) : y( new Y ) { } Y* y; }; int main( unsigned int, char** ) { X<int> x; // break here } walkert@zaphod:foo$ gdb bar (gdb) break main Breakpoint 1 at 0x80484a8: file bar.C, line 15. (gdb) run Starting program: /ms/.global/ny.u/user/w/walkert/foo/bar Breakpoint 1, main () at bar.C:15 15 X<int> x; // break here (gdb) print *x.y $3 = <incomplete type>
Created attachment 102688 [details] Patch that fixes the problem This problem was introduced with the patch at http://gcc.gnu.org/ml/gcc/2003-02/msg02052.html (rth tweaked it a bit before checking it in, but didn't post the exact patch). It wasn't present in early 3.2 releases, and the patch was never added to 3.3, that uses a completely different approach to avoid emitting unused debug information. The problem is that a die for Y is initially created for the declaration only, and add the definition die only later. The problem is that all references to the type point to the declaration node, not to the specification one, so the specification one ends up being regarded as unused, and removed. The attached patch has an assumption I'm not entirely sure we're entitled to make, namely, that as we walk the comp unit dies in the sequence they were generated, when we get to the die for the specification, we'll have already marked the declaration node should it be needed. One the good side, should the assumption not hold, we'll end up with debug info that is no worse than what we have now. I've verified that the patch fixes the reported problem, and that it can build all of libgcc and libstdc++ with debug info with the patch, but I have only just started regression testing.
Regression testing on i686 completed.
From Issue Tracker: Event posted 08-13-2004 11:53am by thomas.walker Looks good in initial testing. -------------------------------------- Event posted 09-02-2004 10:03am by fhirtz We've been able to get the priority compiler fixes in the U3 release, thus this has been included in the gcc-3.2.3-42 release with U3. CHANGING THIS BZ TO RESOLVED=CURRENTRELEASE FOR RHEL3 U3 (per fhirtz)