[PATCH] D136039: [DebugInfo] Fix potential CU mismatch for attachRangesOrLowHighPC

[DianQK via Phabricator via llvm-commits]

DianQK marked an inline comment as done.
DianQK added inline comments.


================
Comment at: llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:1016
                                                    LexicalScope *Scope) {
-  DIE &ScopeDIE = updateSubprogramScopeDIE(Sub);
+  DIE *SPDie = getOrCreateSubprogramDIE(Sub, includeMinimalInlineScopes());
+  DwarfCompileUnit *ContextCU =
----------------
dblaikie wrote:
> Hmm, I'm not following - can you help me understand why this got pulled out of `updateSubprogramScopeDIE`?
I need get `SPDie` to get `ContextCU` before `attachRangesOrLowHighPC`.
The `attachRangesOrLowHighPC` call in `updateSubprogramScopeDIE` and later `createAndAddScopeChildren`.

Maybe I could use the following code:
```
DIE *SPDie = getOrCreateSubprogramDIE(Sub, includeMinimalInlineScopes());
auto *ContextCU = static_cast<DwarfCompileUnit *>(SPDie->getUnit());
DIE &ScopeDIE = ContextCU->updateSubprogramScopeDIE(Sub);
```

I tried. It fails at `cross-cu-inlining-2.ll` (maybe because call `getOrCreateSubprogramDIE` in different CU?).

Dwarf before the change is:
```
0x00000038:       DW_TAG_subprogram [5] * (0x0000002b)
                    DW_AT_low_pc [DW_FORM_addr]	(0x0000000000000010 ".text")
                    DW_AT_high_pc [DW_FORM_data4]	(0x00000001)
                    DW_AT_frame_base [DW_FORM_exprloc]	(DW_OP_reg7 RSP)
                    DW_AT_name [DW_FORM_strp]	( .debug_str[0x00000036] = "bar")
                    DW_AT_decl_file [DW_FORM_data1]	("A.swift")
                    DW_AT_decl_line [DW_FORM_data1]	(21)
                    DW_AT_external [DW_FORM_flag_present]	(true)
```
After:
```
0x00000038:       DW_TAG_subprogram [5]   (0x0000002b)
                    DW_AT_name [DW_FORM_strp]	( .debug_str[0x00000036] = "bar")
                    DW_AT_decl_file [DW_FORM_data1]	("A.swift")
                    DW_AT_decl_line [DW_FORM_data1]	(21)
                    DW_AT_external [DW_FORM_flag_present]	(true)

0x0000003f:       DW_TAG_subprogram [6] * (0x0000002b)
                    DW_AT_low_pc [DW_FORM_addr]	(0x0000000000000010 ".text")
                    DW_AT_high_pc [DW_FORM_data4]	(0x00000001)
                    DW_AT_frame_base [DW_FORM_exprloc]	(DW_OP_reg7 RSP)
```

I think it's ok. But the old version is better?



Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D136039/new/

https://reviews.llvm.org/D136039