The following example produced an inlined block with local variables that
contain correct location expressions (-g -O2):
#include <stdio.h>
#include <stdint.h>
static inline void
m(char *name, int i, int j)
{
// Random syntactical block to be inlined.
do {
volatile int p_i = i;
volatile int p_j = j;
// Change this to void * or char * and var debugloc disappears!?!
volatile uintptr_t p_name = (uintptr_t) name;
// empty asm to force locals into regs.
inlined_label: asm volatile ("" :: "g"(p_name), "g"(p_i), "g"(p_j));
printf("%s: (%d,%d)\n", p_name, p_i, p_j);
} while (0);
}
int
main (int argc, char **argv)
{
m("call", 40, 23);
return 0;
}
$ gcc -g -O2 i.c
$ readelf -w a.out
[...]
<5><3d4>: Abbrev Number: 28 (DW_TAG_variable)
<3d5> DW_AT_abstract_origin: <0x30f>
<3d9> DW_AT_location : 2 byte block: 91 6c (DW_OP_fbreg: -20)
<5><3dc>: Abbrev Number: 28 (DW_TAG_variable)
<3dd> DW_AT_abstract_origin: <0x31a>
<3e1> DW_AT_location : 2 byte block: 91 68 (DW_OP_fbreg: -24)
<5><3e4>: Abbrev Number: 28 (DW_TAG_variable)
<3e5> DW_AT_abstract_origin: <0x325>
<3e9> DW_AT_location : 2 byte block: 91 60 (DW_OP_fbreg: -32)
[...]
But if you change the type of p_name to char * (which would be more natural and
was what the original code did), the DW_AT_location of p_name disappears:
[... as above ...]
volatile char *p_name = name;
[...]
$ gcc -g -O2 i.c
$ readelf -w a.out
[...]
<5><3cf>: Abbrev Number: 28 (DW_TAG_variable)
<3d0> DW_AT_abstract_origin: <0x304>
<3d4> DW_AT_location : 2 byte block: 91 6c (DW_OP_fbreg: -20)
<5><3d7>: Abbrev Number: 28 (DW_TAG_variable)
<3d8> DW_AT_abstract_origin: <0x30f>
<3dc> DW_AT_location : 2 byte block: 91 68 (DW_OP_fbreg: -24)
<5><3df>: Abbrev Number: 29 (DW_TAG_variable)
<3e0> DW_AT_abstract_origin: <0x31a>
[...]
Note, no DW_AT_location for the last variable (p_name), just a
DW_AT_abstract_origin. The other vars (p_i and p_j) still do have both
abstract_origin and location).
--
Summary: Inlined variable debug location disappears when ptr type
Product: gcc
Version: 4.4.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: debug
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: mark at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41097
