https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67436
Bug ID: 67436
Summary: [C++14] Generic lambda capture fails for thread_local
variables
Product: gcc
Version: 5.2.0
Status: UNCONFIRMED
Severity: critical
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: j.s.mueller-roemer at gmx dot net
Target Milestone: ---
I encountered an error with a missing __tls_init after using a thread_local
variable within a generic lambda. I was able to work around this bug by
creating a reference to the thread_local and using the reference in the lambda
instead.
I was not able to reproduce the exact same behavior with a minimal example,
however this code
int main(int, char**)
{
thread_local int foo;
[&] (auto bar) {
foo += bar;
}(1u);
return 0;
}
Causes an internal compiler error
tls_init_bug.cpp: In instantiation of ‘main(int, char**)::<lambda(auto:1)>
[with auto:1 = unsigned int]’:
tls_init_bug.cpp:6:6: required from here
tls_init_bug.cpp:1:5: internal compiler error: in tsubst_decl, at cp/pt.c:10836
int main(int, char**)
^
0x658caa tsubst_decl
../../gcc-5.2.0/gcc/cp/pt.c:10836
0x64b084 tsubst(tree_node*, tree_node*, int, tree_node*)
../../gcc-5.2.0/gcc/cp/pt.c:11934
0x656ba2 tsubst_copy
../../gcc-5.2.0/gcc/cp/pt.c:13093
0x647c18 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
../../gcc-5.2.0/gcc/cp/pt.c:15705
0x648e53 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
../../gcc-5.2.0/gcc/cp/pt.c:15032
0x650162 tsubst_expr
../../gcc-5.2.0/gcc/cp/pt.c:14530
0x64f2c6 tsubst_expr
../../gcc-5.2.0/gcc/cp/pt.c:13941
0x6500ac tsubst_expr
../../gcc-5.2.0/gcc/cp/pt.c:14113
0x6500ac tsubst_expr
../../gcc-5.2.0/gcc/cp/pt.c:14113
0x64ee17 instantiate_decl(tree_node*, int, bool)
../../gcc-5.2.0/gcc/cp/pt.c:20543
0x67e062 mark_used(tree_node*, int)
../../gcc-5.2.0/gcc/cp/decl2.c:5032
0x61db00 build_over_call
../../gcc-5.2.0/gcc/cp/call.c:7501
0x620231 build_op_call_1
../../gcc-5.2.0/gcc/cp/call.c:4345
0x620231 build_op_call(tree_node*, vec<tree_node*, va_gc, vl_embed>**, int)
../../gcc-5.2.0/gcc/cp/call.c:4368
0x6e7408 finish_call_expr(tree_node*, vec<tree_node*, va_gc, vl_embed>**, bool,
bool, int)
../../gcc-5.2.0/gcc/cp/semantics.c:2426
0x69b6e1 cp_parser_postfix_expression
../../gcc-5.2.0/gcc/cp/parser.c:6375
0x69db79 cp_parser_unary_expression
../../gcc-5.2.0/gcc/cp/parser.c:7438
0x69e6f7 cp_parser_binary_expression
../../gcc-5.2.0/gcc/cp/parser.c:8172
0x69eced cp_parser_assignment_expression
../../gcc-5.2.0/gcc/cp/parser.c:8430
0x6a1061 cp_parser_expression
../../gcc-5.2.0/gcc/cp/parser.c:8584
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.
I originally found this error with GCC 5.1 mingw-w64, however it occurs with
GCC 5.2 on linux as well.
