[DWARF][DebugInfo] Function-local types may have concrete out-of-line parent subprogram instead of abstract one #55680
Description
Consider the following example:
template<typename T>
struct A {
A(T &in) : a(in) {}
T a;
};
__attribute__((always_inline))
void foo() {
struct B { int i; };
B objB;
A<B> objA(objB);
}
int main() {
foo();
}Here the function foo() should have 3 subprogram instances emitted: abstract, inlined and out-of-line.
The definition of struct B is expected to be a child of abstract instance of foo().
But actually, it is emitted as a child of out-of-line instance of foo():
$ clang -g -c -o - test.cpp | llvm-dwarfdump - --name=foo --show-children
0x0000002a: DW_TAG_subprogram
DW_AT_low_pc (0x0000000000000000)
DW_AT_high_pc (0x000000000000001b)
DW_AT_frame_base (DW_OP_reg6 RBP)
DW_AT_abstract_origin (0x000000dc "_Z3foov")
...
0x0000004d: DW_TAG_structure_type
DW_AT_calling_convention (DW_CC_pass_by_value)
DW_AT_name ("B")
DW_AT_byte_size (0x04)
DW_AT_decl_file ("test.cpp")
DW_AT_decl_line (9)
...
0x00000062: NULL
0x00000063: NULL
0x000000dc: DW_TAG_subprogram
DW_AT_linkage_name ("_Z3foov")
DW_AT_name ("foo")
DW_AT_decl_file ("test.cpp")
DW_AT_decl_line (8)
DW_AT_external (true)
DW_AT_inline (DW_INL_inlined)
...
0x000000fe: NULL
0x00000118: DW_TAG_inlined_subroutine
DW_AT_abstract_origin (0x000000dc "_Z3foov")
DW_AT_low_pc (0x0000000000000048)
DW_AT_high_pc (0x0000000000000055)
DW_AT_call_file ("test.cpp")
DW_AT_call_line (15)
DW_AT_call_column (0x03)
...
0x0000013c: NULLWhile looking for a context subprogram DIE for foo()::B we are considering to get or create only a concrete subprogram DIE, never accounting an abstract one.
This makes impossible to directly inspect the type in debugger:
Breakpoint 1, foo () at test.cpp:11
11 A<B> objA(objB);
(gdb) ptype B
No symbol "B" in current context.
(gdb) ptype objB
type = struct B {
int i;
}while gcc-compiled example (where struct B gets placed correctly) allows this:
Breakpoint 1, foo () at test.cpp:11
11 A<B> objA(objB);
(gdb) ptype B
type = struct B {
int i;
}
(gdb) ptype objB
type = struct B {
int i;
}