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From: "simon.marchi at polymtl dot ca" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug debug/96937] New: Duplicate DW_TAG_formal_parameter in out-of-line DW_TAG_subprogram instance
Date: Fri, 04 Sep 2020 14:06:23 +0000 [thread overview]
Message-ID: <bug-96937-4@http.gcc.gnu.org/bugzilla/> (raw)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96937
Bug ID: 96937
Summary: Duplicate DW_TAG_formal_parameter in out-of-line
DW_TAG_subprogram instance
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: debug
Assignee: unassigned at gcc dot gnu.org
Reporter: simon.marchi at polymtl dot ca
Target Milestone: ---
While debugging GDB (compiled with GCC master and -O2) with GDB, I get:
972 do_examine (struct format_data fmt, struct gdbarch *gdbarch, CORE_ADDR
addr)
(top-gdb) frame
#0 do_examine (gdbarch=0x249a6b0, addr=0x400636, fmt=..., fmt=...) at
/home/smarchi/src/binutils-gdb/gdb/printcmd.c:972
972 do_examine (struct format_data fmt, struct gdbarch *gdbarch, CORE_ADDR
addr)
Note that the parameters shown by GDB aren't in the same order as in the
function declaration, and that "fmt" is duplicated.
0x0004e0bd: DW_TAG_subprogram
DW_AT_abstract_origin [DW_FORM_ref4] (0x0004a912
"do_examine")
...
0x0004e0cd: DW_TAG_formal_parameter
DW_AT_abstract_origin [DW_FORM_ref4] (0x0004a92e "gdbarch")
...
0x0004e0d6: DW_TAG_formal_parameter
DW_AT_abstract_origin [DW_FORM_ref4] (0x0004a93b "addr")
...
0x0004e0df: DW_TAG_variable
DW_AT_abstract_origin [DW_FORM_ref4] (0x0004a948 "format")
...
0x0004e0e8: DW_TAG_variable
DW_AT_abstract_origin [DW_FORM_ref4] (0x0004a955 "size")
...
... some more variables ...
0x0004e130: DW_TAG_formal_parameter
DW_AT_abstract_origin [DW_FORM_ref4] (0x0004a921 "fmt")
0x0004e135: DW_TAG_formal_parameter
DW_AT_abstract_origin [DW_FORM_ref4] (0x0004a921 "fmt")
This matches what we see in GDB: the parameters are not in the same order as in
the function declaration and fmt is duplicated. The abstract origin has them
correct:
0x0004a912: DW_TAG_subprogram
DW_AT_name [DW_FORM_strp] ("do_examine")
...
0x0004a921: DW_TAG_formal_parameter
DW_AT_name [DW_FORM_string] ("fmt")
...
0x0004a92e: DW_TAG_formal_parameter
DW_AT_name [DW_FORM_strp] ("gdbarch")
...
0x0004a93b: DW_TAG_formal_parameter
DW_AT_name [DW_FORM_strp] ("addr")
...
After reading bug #49828, I presume that the fact that the parameters are not
in the right order is not considered a bug. GDB could cope with that by
sorting them to be in the same order as what's in the abstract origin.
However, having fmt there twice could maybe be considered a bug, hence I am
reporting it.
GDB commit (used as the debugged program):
c5cd900e4f197870812c2d3e2c194871c171ef42
GCC commit: 8ad3fc6ca46c603d9c3efe8e6d4a8f2ff1a893a4
next reply other threads:[~2020-09-04 14:06 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-04 14:06 simon.marchi at polymtl dot ca [this message]
2020-09-04 14:07 ` [Bug debug/96937] " simon.marchi at polymtl dot ca
2020-09-04 14:09 ` simon.marchi at polymtl dot ca
2020-09-07 5:49 ` rguenth at gcc dot gnu.org
2020-09-08 13:20 ` simon.marchi at polymtl dot ca
2020-09-08 13:22 ` simon.marchi at polymtl dot ca
2021-12-09 16:35 ` wcohen at redhat dot com
2021-12-09 16:40 ` wcohen at redhat dot com
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