https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109161
Bug ID: 109161
Summary: Bad CTF generated for stub in function scope
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: debug
Assignee: unassigned at gcc dot gnu.org
Reporter: ibhagat at gcc dot gnu.org
Target Milestone: ---
$ cat t.c
void set_cpu_arch (void) {
typedef struct arch_stack_entry {
const struct arch_stack_entry *prev;
} arch_stack_entry;
static arch_stack_entry *arch_stack_top;
}
$ gcc -gctf -g3 -c t.c
$ objdump --ctf=.ctf t.o will hang.
The hang is because the compiler spits incorrect CTF.
Byte offsets (which point to the location of the various sub-sections in the
CTF section) encoded in the CTF header as seen via poke:
...
cth_funcoff=0U#B,
cth_objtidxoff=4U#B,
cth_funcidxoff=4U#B,
cth_varoff=8U#B,
cth_typeoff=8U#B,
cth_stroff=96U#B,
...
-- The generated CTF section has one function object, and no variables as can
be seen from the offsets in the header. This is OK.
--There are however, generated types; Further, a subset of which are incorrect
(see below).
(poke) ctf_dump_all_types(ctf)
Types:
1: (kind 1) integer void (size 0) (signed)
2: (kind 5) function set_cpu_arch --> ID 1: (kind 1) integer void (size 0)
3: (kind 6) struct arch_stack_entry (size 8)
[0U#b] prev (ID 5)
[0U#b] (ID 3)
4: (kind 12) const --> ID 3: (kind 6) struct arch_stack_entry (size 8)
5: (kind 3) pointer --> ID 4: (kind 12) const --> ID 3: (kind 6) struct
arch_stack_entry (size 8)
[Problem #1] A struct with two members, one of which is unnamed. The type as
defined by the user has one member named prev in the struct => The generated
CTF is incorrect.
[Problem #2] Well, why is there any generated CTF at all ? Both the variable
and the defined type are function-scope; In CTF, only top-level types,
functions, variables are to be described.
