https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94450
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
So the current situation is similar to that of
static inline int foo(int i)
{
static int j;
j = i + 1;
return j;
}
int bar(int i)
{
return foo(i);
}
int baz(int i)
{
return foo(i);
}
here we get
<1><2d>: Abbrev Number: 2 (DW_TAG_subprogram)
<2e> DW_AT_name : foo
<32> DW_AT_decl_file : 1
<33> DW_AT_decl_line : 1
<34> DW_AT_prototyped : 1
<34> DW_AT_type : <0x50>
<38> DW_AT_inline : 3 (declared as inline and inlined)
<39> DW_AT_sibling : <0x50>
...
<2><46>: Abbrev Number: 4 (DW_TAG_variable)
<47> DW_AT_name : j
<49> DW_AT_decl_file : 1
<4a> DW_AT_decl_line : 3
<4b> DW_AT_type : <0x50>
...
<1><57>: Abbrev Number: 6 (DW_TAG_subprogram)
<58> DW_AT_external : 1
<58> DW_AT_name : bar
...
<2><83>: Abbrev Number: 8 (DW_TAG_inlined_subroutine)
<84> DW_AT_abstract_origin: <0x2d>
<88> DW_AT_low_pc : 0x0
<90> DW_AT_high_pc : 0x9
<98> DW_AT_call_file : 1
<99> DW_AT_call_line : 10
<3><9a>: Abbrev Number: 9 (DW_TAG_formal_parameter)
<9b> DW_AT_abstract_origin: <0x3d>
<9f> DW_AT_location : 1 byte block: 55 (DW_OP_reg5 (rdi))
<3><a1>: Abbrev Number: 10 (DW_TAG_lexical_block)
<a2> DW_AT_low_pc : 0x0
<aa> DW_AT_high_pc : 0x9
<4><b2>: Abbrev Number: 11 (DW_TAG_variable)
<b3> DW_AT_abstract_origin: <0x46>
<b7> DW_AT_location : 9 byte block: 3 0 0 0 0 0 0 0 0 (DW_OP_addr: 0)
...
<1><c4>: Abbrev Number: 12 (DW_TAG_subprogram)
<c5> DW_AT_external : 1
<c5> DW_AT_name : baz
...
<2><ec>: Abbrev Number: 8 (DW_TAG_inlined_subroutine)
<ed> DW_AT_abstract_origin: <0x2d>
<f1> DW_AT_low_pc : 0x10
<f9> DW_AT_high_pc : 0x9
<101> DW_AT_call_file : 1
<102> DW_AT_call_line : 15
<3><103>: Abbrev Number: 9 (DW_TAG_formal_parameter)
<104> DW_AT_abstract_origin: <0x3d>
<108> DW_AT_location : 1 byte block: 55 (DW_OP_reg5 (rdi))
<3><10a>: Abbrev Number: 10 (DW_TAG_lexical_block)
<10b> DW_AT_low_pc : 0x10
<113> DW_AT_high_pc : 0x9
<4><11b>: Abbrev Number: 11 (DW_TAG_variable)
<11c> DW_AT_abstract_origin: <0x46>
<120> DW_AT_location : 9 byte block: 3 0 0 0 0 0 0 0 0
(DW_OP_addr: 0)
which also means at least two (in the DW_TAG_inlined_subroutine instances)
concrete variables named 'j'. Not sure if the <46> DIE is a concrete
variable - DWARF doesn't have linkage attributes and the containing
subroutine DIE is marked with DW_AT_inline.
Note we're not emitting a concrete instance of the function which would
contain the "main" instance of 'j'. Not sure what the DWARF for a
standalone concrete instantiation of 'j' would look like.
So current LTO is modeled after this, the early debug contains abstract
instances only (also for non-functions, thus global variables), albeit
not marked as such in all cases. The LTRANS debug contains all concrete
(and inline) instances.
