| Issue |
152576
|
| Summary |
LLVM's DWARF associates instruction from caller with source from inlined callee
|
| Labels |
wrong-debug,
debuginfo
|
| Assignees |
|
| Reporter |
hubert-reinterpretcast
|
Consider the following program:
```c
__attribute__((optnone)) void f1(int x) { }
__attribute__((always_inline)) inline void f2(int *p, int x) {
*p = 42; // moved outside of loop
f1(x);
}
__attribute__((optnone)) void f3(int *p) { }
int main(int argc, char **argv) {
int q;
for (int x = 0; x < argc; ++x) {
f2(&q, x);
}
f3(&q);
return q;
}
```
Compiled with `-O3 -g`, the store of `42` is moved outside of the loop to just before the call to `f3`: https://godbolt.org/z/oYx7YqMhj
```asm
.LBB2_3:
mov dword ptr [rsp + 4], 42
lea rdi, [rsp + 4]
call f3(int*)
```
However, the `lea` instruction, which corresponds to `&q` in the call to `f3` is associated with line 3 (`*p = 42`) in the DWARF:
```
Address Line Column File ISA Discriminator OpIndex Flags
------------------ ------ ------ ------ --- ------------- ------- -------------
0x0000000000000000 1 0 0 0 0 0 is_stmt
0x0000000000000004 1 43 0 0 0 0 is_stmt prologue_end
0x0000000000000010 6 0 0 0 0 0 is_stmt
0x0000000000000015 6 44 0 0 0 0 is_stmt prologue_end
0x0000000000000020 7 0 0 0 0 0 is_stmt
0x0000000000000023 9 21 0 0 0 0 is_stmt prologue_end
0x0000000000000025 9 3 0 0 0 0
0x0000000000000027 0 3 0 0 0 0
0x0000000000000030 4 3 0 0 0 0 is_stmt
0x0000000000000037 9 29 0 0 0 0 is_stmt
0x0000000000000039 9 21 0 0 0 0
0x000000000000003b 9 3 0 0 0 0
0x000000000000003d 3 6 0 0 0 0 is_stmt
0x000000000000004a 12 3 0 0 0 0 is_stmt
0x000000000000004f 13 10 0 0 0 0 is_stmt
0x0000000000000053 13 3 0 0 0 0 epilogue_begin
0x000000000000005a 13 3 0 0 0 0 end_sequence
```
```
ranges.o: file format elf64-x86-64
Disassembly of section .text:
0000000000000020 <main>:
3d: c7 44 24 04 2a 00 00 00 movl $0x2a, 0x4(%rsp)
45: 48 8d 7c 24 04 leaq 0x4(%rsp), %rdi
```
Similarly, the `lea` instruction is represented as being inlined from `f2`:
```
0x000000b0: DW_TAG_inlined_subroutine
DW_AT_abstract_origin (0x00000059 "f2")
DW_AT_ranges (indexed (0x0) rangelist = 0x00000010
[0x000000000000002b, 0x0000000000000037)
[0x000000000000003d, 0x000000000000004a))
```
Clang version info:
```
clang version 22.0.0git (https://github.com/llvm/llvm-project.git 7694856fddbb3fed10076aefec75c9b512cc352e)
```
Partial IR:
```
for.cond.cleanup: ; preds = %for.body, %entry
store i32 42, ptr %q, align 4, !dbg !52, !DIAssignID !61
call void @f3(ptr noundef nonnull %q), !dbg !62
; ...
!52 = !DILocation(line: 3, column: 6, scope: !53, inlinedAt: !59)
!53 = distinct !DISubprogram(name: "f2", scope: !1, file: !1, line: 2, type: !54, scopeLine: 2, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !56)
; ...
!59 = distinct !DILocation(line: 10, column: 5, scope: !60)
; ...
!62 = !DILocation(line: 12, column: 3, scope: !33)
```
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