[llvm] 60f406c - [CodeExtractor] Only rewrite scope of non-inlined variables

[Felipe de Azevedo Piovezan via llvm-commits]

Author: Felipe de Azevedo Piovezan
Date: 2022-12-10T14:38:09-05:00
New Revision: 60f406c4db5ba1ed6d66567ddaef4b86386496e1

URL: https://github.com/llvm/llvm-project/commit/60f406c4db5ba1ed6d66567ddaef4b86386496e1
DIFF: https://github.com/llvm/llvm-project/commit/60f406c4db5ba1ed6d66567ddaef4b86386496e1.diff

LOG: [CodeExtractor] Only rewrite scope of non-inlined variables

When a dbg.value instruction for a variable V is extracted into a new
function, the scope of the underlying variable should be set to the new
function iff V was in the scope of the old function (i.e. it hadn't been
inlined). Prior to this patch, the code extractor would always update
the scope of V.

Differential Revision: https://reviews.llvm.org/D139669

Added: 
    

Modified: 
    llvm/lib/Transforms/Utils/CodeExtractor.cpp
    llvm/test/Transforms/HotColdSplit/transfer-debug-info.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Utils/CodeExtractor.cpp b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
index 08e224e097328..999744378dd9b 100644
--- a/llvm/lib/Transforms/Utils/CodeExtractor.cpp
+++ b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
@@ -1588,17 +1588,20 @@ static void fixupDebugInfoPostExtraction(Function &OldFunc, Function &NewFunc,
       DebugIntrinsicsToDelete.push_back(DVI);
       continue;
     }
-
-    // Point the intrinsic to a fresh variable within the new function.
-    DILocalVariable *OldVar = DVI->getVariable();
-    DINode *&NewVar = RemappedMetadata[OldVar];
-    if (!NewVar)
-      NewVar = DIB.createAutoVariable(
-          NewSP, OldVar->getName(), OldVar->getFile(), OldVar->getLine(),
-          OldVar->getType(), /*AlwaysPreserve=*/false, DINode::FlagZero,
-          OldVar->getAlignInBits());
-    DVI->setVariable(cast<DILocalVariable>(NewVar));
+    // If the variable was in the scope of the old function, i.e. it was not
+    // inlined, point the intrinsic to a fresh variable within the new function.
+    if (!DVI->getDebugLoc().getInlinedAt()) {
+      DILocalVariable *OldVar = DVI->getVariable();
+      DINode *&NewVar = RemappedMetadata[OldVar];
+      if (!NewVar)
+        NewVar = DIB.createAutoVariable(
+            NewSP, OldVar->getName(), OldVar->getFile(), OldVar->getLine(),
+            OldVar->getType(), /*AlwaysPreserve=*/false, DINode::FlagZero,
+            OldVar->getAlignInBits());
+      DVI->setVariable(cast<DILocalVariable>(NewVar));
+    }
   }
+
   for (auto *DII : DebugIntrinsicsToDelete)
     DII->eraseFromParent();
   DIB.finalizeSubprogram(NewSP);

diff  --git a/llvm/test/Transforms/HotColdSplit/transfer-debug-info.ll b/llvm/test/Transforms/HotColdSplit/transfer-debug-info.ll
index f9191cdf675c7..b296bbbdac632 100644
--- a/llvm/test/Transforms/HotColdSplit/transfer-debug-info.ll
+++ b/llvm/test/Transforms/HotColdSplit/transfer-debug-info.ll
@@ -31,6 +31,10 @@ target triple = "x86_64-apple-macosx10.14.0"
 ; CHECK-NEXT: call void @sink(i32 [[ADD1]]), !dbg [[LINE2:![0-9]+]]
 ; CHECK-NEXT: call void @sink(i32 [[ADD1]]), !dbg [[LINE3:![0-9]+]]
 
+; CHECK-NEXT: call void @llvm.dbg.value(metadata i32 [[ADD1]]
+; CHECK-SAME:      metadata [[VAR_FROM_INLINE_ME:![0-9]+]]
+; CHECK-SAME:      !dbg [[LINE2]]
+
 ; - The DISubprogram for @foo.cold.1 has an empty DISubroutineType
 ; CHECK: [[FILE:![0-9]+]] = !DIFile(filename: "<stdin>"
 ; CHECK: [[EMPTY_MD:![0-9]+]] = !{}
@@ -47,6 +51,9 @@ target triple = "x86_64-apple-macosx10.14.0"
 ; CHECK: [[INLINED_SCOPE1]] = !DILexicalBlock(scope: [[INLINED_SCOPE2:![0-9]*]], file: [[FILE]], line: 4, column: 4)
 ; CHECK: [[INLINED_SCOPE2]] = !DILexicalBlock(scope: [[NEWSCOPE]], file: [[FILE]], line: 5, column: 5)
 
+; CHECK: [[VAR_FROM_INLINE_ME]] = !DILocalVariable(name: "var_from_inline_me",
+; CHECK-SAME:                                      scope: [[INLINE_ME_SCOPE]]
+
 define void @foo(i32 %arg1) !dbg !6 {
 entry:
   %var = add i32 0, 0, !dbg !11
@@ -64,6 +71,7 @@ if.end:                                           ; preds = %entry
   call void @llvm.dbg.value(metadata i32 %add1, metadata !9, metadata !DIExpression(DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value)), !dbg !11
   call void @sink(i32 %add1), !dbg !13 ; inlined from @inline_me
   call void @sink(i32 %add1), !dbg !14 ; not inlined, but inside some scope of foo
+  call void @llvm.dbg.value(metadata i32 %add1, metadata !17, metadata !DIExpression()), !dbg !13 ; variable from @inline_me, should preserve scope in !17.
   ret void
 }
 
@@ -96,3 +104,4 @@ define void @inline_me() !dbg !12{
 !14 = !DILocation(line: 3, column: 3, scope: !15)
 !15 = distinct !DILexicalBlock(scope: !16, file: !1, line: 4, column: 4)
 !16 = distinct !DILexicalBlock(scope: !6, file: !1, line: 5, column: 5)
+!17 = !DILocalVariable(name: "var_from_inline_me", scope: !12, file: !1, line: 1, type: !10)