[Bug debug/98716] [11 Regression] sanitizer regressions by r11-6755
jakub at gcc dot gnu.org
gcc-bugzilla@gcc.gnu.org
Mon Jan 18 13:18:32 GMT 2021
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98716
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
So, seems when asan alloca_big_alignment test is built with -gdwarf-4 -flto, we
have:
Offset: 0x57
Length: 214
DWARF Version: 4
Prologue Length: 105
Minimum Instruction Length: 1
Maximum Ops per Instruction: 1
Initial value of 'is_stmt': 1
Line Base: -5
Line Range: 14
Opcode Base: 13
Opcodes:
Opcode 1 has 0 args
Opcode 2 has 1 arg
Opcode 3 has 1 arg
Opcode 4 has 1 arg
Opcode 5 has 1 arg
Opcode 6 has 0 args
Opcode 7 has 0 args
Opcode 8 has 0 args
Opcode 9 has 1 arg
Opcode 10 has 0 args
Opcode 11 has 0 args
Opcode 12 has 1 arg
The Directory Table (offset 0x73):
1 /usr/src/gcc/gcc/testsuite/c-c++-common/asan
The File Name Table (offset 0xa1):
Entry Dir Time Size Name
1 1 0 0 alloca_big_alignment.c
2 0 0 0 <built-in>
Line Number Statements:
[0x000000ca] Set column to 56
[0x000000cc] Extended opcode 2: set Address to 0x4011f0
[0x000000d7] Special opcode 12: advance Address by 0 to 0x4011f0 and Line by
7 to 8
[0x000000d8] Set is_stmt to 0
[0x000000d9] Copy (view 1)
[0x000000da] Set column to 17
[0x000000dc] Special opcode 20: advance Address by 1 to 0x4011f1 and Line by
1 to 9
[0x000000dd] Special opcode 89: advance Address by 6 to 0x4011f7 and Line by
0 to 9
[0x000000de] Set column to 56
[0x000000e0] Special opcode 130: advance Address by 9 to 0x401200 and Line
by -1 to 8
[0x000000e1] Advance PC by constant 17 to 0x401211
[0x000000e2] Special opcode 47: advance Address by 3 to 0x401214 and Line by
0 to 8
[0x000000e3] Set column to 3
[0x000000e5] Set is_stmt to 1
[0x000000e6] Special opcode 90: advance Address by 6 to 0x40121a and Line by
1 to 9
[0x000000e7] Set is_stmt to 0
This is for a TU created by LTO, which in .debug_info has:
<565> DW_AT_name : (indirect string, offset: 0x676): <artificial>
<569> DW_AT_comp_dir : (indirect string, offset: 0x652):
/usr/src/gcc/obj2/gcc/testsuite/gcc
Now, with -gdwarf-5 -flto, is still has:
<566> DW_AT_name : (indirect line string, offset: 0x11d):
<artificial>
<56a> DW_AT_comp_dir : (indirect line string, offset: 0x12a):
/usr/src/gcc/obj2/gcc/testsuite/gcc
but the .debug_lines part starts with:
Offset: 0x57
Length: 162
DWARF Version: 5
Address size (bytes): 8
Segment selector (bytes): 0
Prologue Length: 51
Minimum Instruction Length: 1
Maximum Ops per Instruction: 1
Initial value of 'is_stmt': 1
Line Base: -5
Line Range: 14
Opcode Base: 13
Opcodes:
Opcode 1 has 0 args
Opcode 2 has 1 arg
Opcode 3 has 1 arg
Opcode 4 has 1 arg
Opcode 5 has 1 arg
Opcode 6 has 0 args
Opcode 7 has 0 args
Opcode 8 has 0 args
Opcode 9 has 1 arg
Opcode 10 has 0 args
Opcode 11 has 0 args
Opcode 12 has 1 arg
The Directory Table (offset 0x79, lines 2, columns 1):
Entry Name
0 (indirect line string, offset: 0x12a):
/usr/src/gcc/obj2/gcc/testsuite/gcc
1 (indirect line string, offset: 0x14e):
/usr/src/gcc/gcc/testsuite/c-c++-common/asan
The File Name Table (offset 0x87, lines 3, columns 2):
Entry Dir Name
0 0 (indirect line string, offset: 0x11d): <artificial>
1 1 (indirect line string, offset: 0x1b3): alloca_big_alignment.c
2 0 (indirect line string, offset: 0x17b): <built-in>
Line Number Statements:
[0x00000096] Set column to 56
[0x00000098] Extended opcode 2: set Address to 0x4011f0
[0x000000a3] Special opcode 12: advance Address by 0 to 0x4011f0 and Line by
7 to 8
[0x000000a4] Set is_stmt to 0
[0x000000a5] Copy (view 1)
[0x000000a6] Set column to 17
[0x000000a8] Special opcode 20: advance Address by 1 to 0x4011f1 and Line by
1 to 9
[0x000000a9] Special opcode 89: advance Address by 6 to 0x4011f7 and Line by
0 to 9
[0x000000aa] Set column to 56
[0x000000ac] Special opcode 130: advance Address by 9 to 0x401200 and Line
by -1 to 8
[0x000000ad] Advance PC by constant 17 to 0x401211
[0x000000ae] Special opcode 47: advance Address by 3 to 0x401214 and Line by
0 to 8
[0x000000af] Set column to 3
[0x000000b1] Set is_stmt to 1
[0x000000b2] Special opcode 90: advance Address by 6 to 0x40121a and Line by
1 to 9
[0x000000b3] Set is_stmt to 0
So the important difference is in that DWARF5 has the 0 entry in the filename
table while DWARF4 does not.
DWARF5 Table 6.4: Line number program initial state says that the
initial file is 1, which means I think read_line_program in libbacktrace is
incorrect for DWARF5.
More information about the Gcc-bugs
mailing list