https://sourceware.org/bugzilla/show_bug.cgi?id=29337
Bug ID: 29337
Summary: [readelf] CU/TU mixup in .gdb_index
Product: binutils
Version: 2.39 (HEAD)
Status: NEW
Severity: normal
Priority: P2
Component: binutils
Assignee: unassigned at sourceware dot org
Reporter: vries at gcc dot gnu.org
Target Milestone: ---
Consider a hello.c (probably not relevant, just listing what I used):
...
$ cat hello.c
#include <stdio.h>
int
main (void)
{
printf
("hello00000000000000000000000000000000000000000000000000000000000000000000\n");
return 0;
}
...
We compile with gcc 7.5.0, and add a .debug_types section:
...
$ gcc hello.c -g -fdebug-types-section
...
And we add a .debug_index section:
...
$ gdb-add-index a.out
...
Let's print the index entries for a type and a variable:
With 2.37:
...
$ ~/binutils/install/bin/readelf -wg a.out | egrep "_IO_FILE|stdout"
[718] _IO_FILE: T0 [static, type]
[823] stdout: 3 [global, variable]
...
Well, that looks all right.
We have 6 CUs and 1 TU:
...
CU table:
[ 0] 0x0 - 0x2d
[ 1] 0x2e - 0x6c
[ 2] 0x6d - 0x8e
[ 3] 0x8f - 0x184
[ 4] 0x185 - 0x33c
[ 5] 0x33d - 0x35e
TU table:
[ 0] 0x0 0x1d f4c23649b49166b7
...
and indeed the _IO_FILE type is part of the .debug_types section, which
contains a single type unit:
...
Contents of the .debug_types section:
Compilation Unit @ offset 0x0:
Length: 0x22a (32-bit)
Version: 4
Abbrev Offset: 0x59
Pointer Size: 8
Signature: 0xf4c23649b49166b7
Type Offset: 0x1d
<0><17>: Abbrev Number: 1 (DW_TAG_type_unit)
<18> DW_AT_language : 12 (ANSI C99)
<19> DW_AT_stmt_list : 0xe8
<1><1d>: Abbrev Number: 2 (DW_TAG_structure_type)
<1e> DW_AT_name : (indirect string, offset: 0x282): _IO_FILE
...
and the stdout variable is part of the CU at 0x8f:
...
Compilation Unit @ offset 0x8f:
Length: 0xf2 (32-bit)
Version: 4
Abbrev Offset: 0x59
Pointer Size: 8
<0><9a>: Abbrev Number: 13 (DW_TAG_compile_unit)
...
<1><120>: Abbrev Number: 16 (DW_TAG_variable)
<121> DW_AT_name : (indirect string, offset: 0x40d): stdout
...
which is listed with index 3 in the CU table.
Let's try again, with 2.38:
...
$ ~/binutils/install/bin/readelf -wg a.out | egrep "_IO_FILE|stdout"
[718] _IO_FILE: T0 [static, type]
[823] stdout: 3 [global, variable]
...
Still looking good.
Not let's try with master:
...
$ ~/binutils/install/bin/readelf -wg a.out | egrep "_IO_FILE|stdout"
[718] _IO_FILE: T3 [static, type]
[823] stdout: T0 [global, variable]
...
Both T3 and T0 look wrong.
--
You are receiving this mail because:
You are on the CC list for the bug.
