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[Bug debug/39474] New: DW_AT_location missing for unused variables even at -O0
- From: "jan dot kratochvil at redhat dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 16 Mar 2009 18:56:31 -0000
- Subject: [Bug debug/39474] New: DW_AT_location missing for unused variables even at -O0
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
It is a regression since gcc-4.3 but it was found only at artificial (GDB)
testcase. Also at -O2 such behavior is even expected.
The variable is considered as optimized-out which should not happen on -O0.
Testcase:
------------------------------------------------------------------------------
int
main (void)
{
int var;
return 0;
}
------------------------------------------------------------------------------
gcc -Wall -g
WRONG gcc-4.4:
< c> DW_AT_producer : (indirect string, offset: 0xb): GNU C 4.4.0
20090315 (experimental)
<1><2d>: Abbrev Number: 2 (DW_TAG_subprogram)
<2f> DW_AT_name : (indirect string, offset: 0x39): main
<2><52>: Abbrev Number: 3 (DW_TAG_variable)
<53> DW_AT_name : var
<59> DW_AT_type : <0x5e>
Correct gcc-4.3:
< c> DW_AT_producer : (indirect string, offset: 0xf): GNU C 4.3.2
20081105 (Red Hat 4.3.2-7)
<1><2d>: Abbrev Number: 2 (DW_TAG_subprogram)
<2f> DW_AT_name : (indirect string, offset: 0x36): main
<2><52>: Abbrev Number: 3 (DW_TAG_variable)
<53> DW_AT_name : var
<59> DW_AT_type : <0x61>
<5d> DW_AT_location : 2 byte block: 91 6c (DW_OP_fbreg: -20)
--
Summary: DW_AT_location missing for unused variables even at -O0
Product: gcc
Version: 4.4.0
Status: UNCONFIRMED
Severity: minor
Priority: P3
Component: debug
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: jan dot kratochvil at redhat dot com
GCC target triplet: x86_64-unknown-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39474