[PATCH] D139579: [WebAssembly] Print DEBUG_VALUE once for target indices

[Heejin Ahn via Phabricator via llvm-commits]

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`DEBUG_VALUE` comments are printed before an instruction, so they are
not printed with `AddComment` method as other comments are, but printed
using `emitRawComment` method. But currently `emitDebugValueComment`
calls `emitRawComment` twice for target-index-based `DBG_VALUE`s: once
in the `switch`-`case`,
https://github.com/llvm/llvm-project/blob/d77ae7f2513504655e555cd326208598093d66e2/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp#L1192-L1193
and again at the end of the method:
https://github.com/llvm/llvm-project/blob/d77ae7f2513504655e555cd326208598093d66e2/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp#L1227-L1228

This makes them printed twice. I think this happened through multiple
modifications modifying and refactoring this method.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D139579

Files:
  llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
  llvm/test/DebugInfo/WebAssembly/dbg-value-comment.mir


Index: llvm/test/DebugInfo/WebAssembly/dbg-value-comment.mir
===================================================================
--- /dev/null
+++ llvm/test/DebugInfo/WebAssembly/dbg-value-comment.mir
@@ -0,0 +1,51 @@
+# RUN: llc -start-after wasm-debug-fixup %s -o - | FileCheck %s
+
+# Test if '#DEBUG_VALUE' comments for target indices are printed correctly.
+
+--- |
+  target triple = "wasm32-unknown-unknown"
+
+  define void @test_dbg_value_comment() !dbg !5 {
+    call void @llvm.dbg.value(metadata i32 0, metadata !9, metadata !DIExpression()), !dbg !10
+    call void @llvm.dbg.value(metadata i32 0, metadata !11, metadata !DIExpression()), !dbg !10
+    ret void
+  }
+
+  declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+  !llvm.dbg.cu = !{!0}
+  !llvm.module.flags = !{!2, !3, !4}
+
+  !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, emissionKind: FullDebug)
+  !1 = !DIFile(filename: "test.c", directory: "")
+  !2 = !{i32 7, !"Dwarf Version", i32 5}
+  !3 = !{i32 2, !"Debug Info Version", i32 3}
+  !4 = !{i32 1, !"wchar_size", i32 4}
+  !5 = distinct !DISubprogram(name: "test_dbg_value_comment", scope: !1, file: !1, line: 1, type: !6, scopeLine: 1, unit: !0)
+  !6 = !DISubroutineType(types: !7)
+  !7 = !{!8}
+  !8 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+  !9 = !DILocalVariable(name: "var0", scope: !5, file: !1, line: 2, type: !8)
+  !10 = !DILocation(line: 0, scope: !5)
+  !11 = !DILocalVariable(name: "var1", scope: !5, file: !1, line: 2, type: !8)
+...
+
+---
+# CHECK-LABEL: .globl test_dbg_value_comment
+name: test_dbg_value_comment
+liveins:
+  - { reg: '$arguments' }
+body: |
+  ; One '#DEBUG_VALUE' comment should be printed per one 'DBG_VALUE'
+  ; instruction. There was a bug that makes this printed twice for
+  ; target-index-based 'DBG_VALUE's.
+  ; CHECK: bb.0:
+  ; CHECK-NEXT: #DEBUG_VALUE: test_dbg_value_comment:var0 <- !target-index(0,1)
+  ; CHECK-NEXT: #DEBUG_VALUE: test_dbg_value_comment:var1 <- !target-index(2,2)
+  ; CHECK-NEXT: return
+  bb.0:
+    liveins: $arguments
+    DBG_VALUE target-index(wasm-local) + 1, $noreg, !9, !DIExpression(), debug-location !10
+    DBG_VALUE target-index(wasm-operand-stack) + 2, $noreg, !11, !DIExpression(), debug-location !10
+    RETURN implicit-def dead $arguments
+...
Index: llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
===================================================================
--- llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -1179,8 +1179,6 @@
     }
     case MachineOperand::MO_TargetIndex: {
       OS << "!target-index(" << Op.getIndex() << "," << Op.getOffset() << ")";
-      // NOTE: Want this comment at start of line, don't emit with AddComment.
-      AP.OutStreamer->emitRawComment(OS.str());
       break;
     }
     case MachineOperand::MO_Register:


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