https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91381
Bug ID: 91381
Summary: ARM NEON register variable DWARF incorrect
Product: gcc
Version: 7.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: debug
Assignee: unassigned at gcc dot gnu.org
Reporter: calum.west at analog dot com
Target Milestone: ---
When producing debug information for a 128-bit Q register variable using Q8 and
above, the debug information produced incorrectly repeats the same D register
twice as the operand of the DW_OP_piece operation.
Example ( using 8.3-2019.03 found on arm.com ):
/***main.c***/
#include <arm_neon.h>
#include <stdint.h>
int main()
{
register uint32x4_t neon_reg asm ("q8") = {1,2,3,4};
return 0;
}
/************/
$./arm-eabi-g++ -g -mcpu=cortex-a5 -mfloat-abi=hard --specs=nosys.specs main.c
-o main.o
$ ./arm-eabi-objdump.exe -g main.o
...
<2><e6>: Abbrev Number: 8 (DW_TAG_variable)
<e7> DW_AT_name : (indirect string, offset: 0x147): neon_reg
<eb> DW_AT_decl_file : 1
<ec> DW_AT_decl_line : 11
<ed> DW_AT_decl_column : 24
<ee> DW_AT_type : <0xad>
<f2> DW_AT_location : 10 byte block: 90 90 2 93 8 90 90 2 93 8
(DW_OP_regx: 272 (r272); DW_OP_piece: 8; DW_OP_regx: 272 (r272); DW_OP_piece:
8)
...
This last attribute should be (DW_OP_regx: 272 (r272); DW_OP_piece: 8;
DW_OP_regx: 273 (r273); DW_OP_piece: 8) and similar for other registers >Q8.
Registers <Q8 appear to work correctly.
I've briefly tested on different versions and with different variations of the
g-dwarf($version) and g-strictdwarf switch and found the same results.
