gccgo: crash on reference to undefined name

[h4ck3rm1k3]

package main
func crash() {
        xpc := pc
}

gccgo (GCC) 5.0.0 20150331 (experimental) on ppc64le

error: reference to undefined name ‘pc’
  xpc := pc

go1: internal compiler error: in set_type, at go/gofrontend/expressions.cc:15628
0x101d2b0f Numeric_constant::set_type(Type*, bool, Location)
        ../../gcc/go/gofrontend/expressions.cc:15628
0x101d45a7 Const_expression::do_numeric_constant_value(Numeric_constant*) const
        ../../gcc/go/gofrontend/expressions.cc:2691
0x101d5493 Expression::numeric_constant_value(Numeric_constant*) const
        ../../gcc/go/gofrontend/expressions.h:490
0x101d5493 Binary_expression::do_lower(Gogo*, Named_object*, Statement_inserter*, int)
        ../../gcc/go/gofrontend/expressions.cc:4927
0x101fbb1f Expression::lower(Gogo*, Named_object*, Statement_inserter*, int)
        ../../gcc/go/gofrontend/expressions.h:699
0x101fbb1f Lower_parse_tree::expression(Expression**)
    ../../gcc/go/gofrontend/gogo.cc:2616
0x101b631f Expression::traverse(Expression**, Traverse*)
        ../../gcc/go/gofrontend/expressions.cc:43
0x10246a67 Statement::traverse_expression(Traverse*, Expression**)
        ../../gcc/go/gofrontend/statements.cc:83
0x10246a67 If_statement::do_traverse(Traverse*)
        ../../gcc/go/gofrontend/statements.cc:3194
0x10249677 Statement::traverse_contents(Traverse*)
        ../../gcc/go/gofrontend/statements.cc:61
0x101fc5f3 Lower_parse_tree::statement(Block*, unsigned long*, Statement*)
    ../../gcc/go/gofrontend/gogo.cc:2570
0x102495cb Statement::traverse(Block*, unsigned long*, Traverse*)
    ../../gcc/go/gofrontend/statements.cc:43
0x10200c7b Block::traverse(Traverse*)
        ../../gcc/go/gofrontend/gogo.cc:5578
0x102578fb Block_statement::do_traverse(Traverse*)
        ../../gcc/go/gofrontend/statements.cc:1814
0x10249603 Statement::traverse(Block*, unsigned long*, Traverse*)
        ../../gcc/go/gofrontend/statements.cc:53
0x10200c7b Block::traverse(Traverse*)
        ../../gcc/go/gofrontend/gogo.cc:5578
0x10200fcf Function::traverse(Traverse*)
        ../../gcc/go/gofrontend/gogo.cc:4739
0x10209b63 Lower_parse_tree::function(Named_object*)
        ../../gcc/go/gofrontend/gogo.cc:2547
0x10204a7f Bindings::traverse(Traverse*, bool)
        ../../gcc/go/gofrontend/gogo.cc:7353
0x10204c3b Gogo::traverse(Traverse*)
        ../../gcc/go/gofrontend/gogo.cc:2367
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.

The gccgo-5 (Debian 5-20150226-1) 5.0.0 20150226 (experimental) [trunk revision 220999]

test.go:3:16: error: reference to undefined name ‘pc’
         xpc := pc

commit 3897c269d567836ca49848322062d1c8c43f4177
Author: gccadmin gccadmin@138bc75d-0d04-0410-961f-82ee72b054a4
Date: Tue Mar 31 00:16:11 2015 +0000

[ianlancetaylor]

I did a full bootstrap of GCC on a powerpc64le machine I have here, from gcc trunk SVN revision 221802. I can not recreate the problem. I just get the error message and no compiler crash.

I don't plan to look at this further, but let me know if you track it down.

[h4ck3rm1k3]

ok. I can do that next time I upgrade. I dont need this, it was just found with my permutation tool. I wonder if we have a test suite for regression testing?

[minux]

gccgo is using mostly the same testsuite as gc's. Use "make check-go" to run it.

[ianlancetaylor]

In fact the gccgo testsuite is an exact copy, though it has a different driver.

But I'm not all that interested in adding crash-on-invalid bugs to the testsuite. They should be fixed, of course, but I'd rather only add invalid code to the testsuite to test error messages and to make sure that the compiler correctly rejects invalid code. I don't think that compiler crashes on invalid code are worth growing the testsuite for.

[h4ck3rm1k3]

fine with me, lets just leave this one for now until someone finds time for it. I will focus on valid code now. just trying to help.

[ianlancetaylor]

I appreciate the help. I do want to fix the problem if we can identify it. I only meant to explain that I don't think that crash-on-invalid tests need to be added to the testsuite.

[ianlancetaylor]

Sorry, didn't mean to close this.

[gopherbot]

CL https://golang.org/cl/10483 mentions this issue.