[CodeExtractor] Preserve entire scope of labels when moving them

When a dbg.label is moved into a new function, its corresponding scope
should be preserved, with the exception of the subprogram at the end of
the scope chain, which should now be the subprogram of the destination
function. See D139671.

Differential Revision: https://reviews.llvm.org/D139849

Author: felipepiovezan

llvm/lib/Transforms/Utils/CodeExtractor.cpp

@@ -1564,9 +1564,12 @@ static void fixupDebugInfoPostExtraction(Function &OldFunc, Function &NewFunc,
         continue;
       DILabel *OldLabel = DLI->getLabel();
       DINode *&NewLabel = RemappedMetadata[OldLabel];
-      if (!NewLabel)
-        NewLabel = DILabel::get(Ctx, NewSP, OldLabel->getName(),
+      if (!NewLabel) {
+        DILocalScope *NewScope = DILocalScope::cloneScopeForSubprogram(
+            *OldLabel->getScope(), *NewSP, Ctx, Cache);
+        NewLabel = DILabel::get(Ctx, NewScope, OldLabel->getName(),
                                 OldLabel->getFile(), OldLabel->getLine());
+      }
       DLI->setArgOperand(0, MetadataAsValue::get(Ctx, NewLabel));
       continue;
     }

llvm/test/Transforms/HotColdSplit/split-out-dbg-label.ll

@@ -13,6 +13,7 @@ target triple = "x86_64-apple-macosx10.14.0"
 ; CHECK-LABEL: define {{.*}}@foo.cold.1
 ; CHECK: llvm.dbg.label(metadata [[LABEL:![0-9]+]]), !dbg [[LINE:![0-9]+]]
 ; CHECK: llvm.dbg.label(metadata [[LABEL_IN_INLINE_ME:![0-9]+]]), !dbg [[LINE2:![0-9]+]]
+; CHECK: llvm.dbg.label(metadata [[SCOPED_LABEL:![0-9]+]]), !dbg [[LINE]]
 
 ; CHECK: [[FILE:![0-9]+]] = !DIFile
 ; CHECK: [[INLINE_ME_SCOPE:![0-9]+]] = distinct !DISubprogram(name: "inline_me"
@@ -21,6 +22,8 @@ target triple = "x86_64-apple-macosx10.14.0"
 ; CHECK: [[LABEL]] = !DILabel(scope: [[SCOPE]], name: "bye", file: [[FILE]], line: 28
 ; CHECK: [[LABEL_IN_INLINE_ME]] = !DILabel(scope: [[INLINE_ME_SCOPE]], name: "label_in_@inline_me", file: [[FILE]], line: 29
 ; CHECK: [[LINE2]] = !DILocation(line: 2, column: 2, scope: [[INLINE_ME_SCOPE]], inlinedAt: [[LINE]]
+; CHECK: [[SCOPED_LABEL]] = !DILabel(scope: [[SCOPE_IN_FOO:![0-9]+]], name: "scoped_label_in_foo", file: [[FILE]], line: 30
+; CHECK: [[SCOPE_IN_FOO]] = !DILexicalBlock(scope: [[SCOPE]], file: [[FILE]], line: 31, column: 31)
 
 define void @foo(i32 %arg1) !dbg !6 {
 entry:
@@ -33,6 +36,7 @@ if.then:                                          ; preds = %entry
 if.end:                                           ; preds = %entry
   call void @llvm.dbg.label(metadata !12), !dbg !11
   call void @llvm.dbg.label(metadata !14), !dbg !15
+  call void @llvm.dbg.label(metadata !16), !dbg !11
   call void @sink()
   ret void
 }
@@ -65,3 +69,5 @@ define void @inline_me() !dbg !13 {
 !13 = distinct !DISubprogram(name: "inline_me", linkageName: "inline_me", scope: null, file: !1, line: 1, type: !7, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: true, unit: !0, retainedNodes: !8)
 !14 = !DILabel(scope: !13, name: "label_in_@inline_me", file: !1, line: 29)
 !15 = !DILocation(line: 2, column: 2, scope: !13, inlinedAt: !11)
+!16 = !DILabel(scope: !17, name: "scoped_label_in_foo", file: !1, line: 30)
+!17 = distinct !DILexicalBlock(scope: !6, file: !1, line: 31, column: 31)