[CodeExtractor] Use scope reparenting helper to update loop dbg loc

[fdeazeve]

Summary

Apply the same strategy from D139217 to loop debug locations.

Depends on D139849

llvm/lib/Transforms/Utils/CodeExtractor.cpp

static void fixupDebugInfoPostExtraction(Function &OldFunc, Function &NewFunc,
   // Fix up the scope information attached to the line locations in the new
   // function.
   for (Instruction &I : instructions(NewFunc)) {
     if (const DebugLoc &DL = I.getDebugLoc())
       I.setDebugLoc(
           DebugLoc::replaceInlinedAtSubprogram(DL, *NewSP, Ctx, Cache));
 
     // Loop info metadata may contain line locations. Fix them up.
-    auto updateLoopInfoLoc = [&Ctx, NewSP](Metadata *MD) -> Metadata * {
+    auto updateLoopInfoLoc = [&Ctx, &Cache, NewSP](Metadata *MD) -> Metadata * {
       if (auto *Loc = dyn_cast_or_null<DILocation>(MD))
-        return DILocation::get(Ctx, Loc->getLine(), Loc->getColumn(), NewSP,
-                               nullptr);
+        return DebugLoc::replaceInlinedAtSubprogram(Loc, *NewSP, Ctx, Cache);
       return MD;
     };
     updateLoopMetadataDebugLocations(I, updateLoopInfoLoc);
   }
   if (!TheCall.getDebugLoc())
     TheCall.setDebugLoc(DILocation::get(Ctx, 0, 0, OldSP));
 
   eraseDebugIntrinsicsWithNonLocalRefs(NewFunc);

llvm/test/Transforms/HotColdSplit/update-split-loop-metadata.ll

 ; RUN: opt -passes=hotcoldsplit -hotcoldsplit-threshold=0 -S < %s | FileCheck %s
 
 ; Check that llvm.loop metadata extracted by CodeExtractor is updated so that
 ; the debug locations it contains have the right scope.
 
 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-apple-macosx10.14.0"
 
 ; CHECK-LABEL: define {{.*}}@basic.cold.1
 ; CHECK: br i1 {{.*}}, !llvm.loop [[LOOP_MD:![0-9]+]]
 
 ; The scope for these debug locations should be @basic.cold.1, not @basic.
 ; CHECK: [[SCOPE:![0-9]+]] = distinct !DISubprogram(name: "basic.cold.1"
-; CHECK: [[LOOP_MD]] = distinct !{[[LOOP_MD]], [[LINE:![0-9]+]], [[LINE]]}
+; CHECK: [[LOOP_MD]] = distinct !{[[LOOP_MD]], [[LINE:![0-9]+]], [[LINE2:![0-9]+]]}
 ; CHECK: [[LINE]] = !DILocation(line: 1, column: 1, scope: [[SCOPE]])
+; CHECK: [[LINE2]] = !DILocation(line: 2, column: 2, scope: [[LEX_SCOPE:![0-9]+]])
+; CHECK: [[LEX_SCOPE]] = !DILexicalBlock(scope: [[SCOPE]], file: !{{[0-9]+}}, line: 3, column: 3)
 
 define void @basic(ptr %p, i32 %k) !dbg !6 {
 entry:
   %cmp3 = icmp slt i32 0, %k
   br i1 %cmp3, label %for.body.lr.ph, label %for.end
 
 for.body.lr.ph:                                   ; preds = %entry
   br label %for.body

 !2 = !{}
 !3 = !{i32 22}
 !4 = !{i32 12}
 !5 = !{i32 2, !"Debug Info Version", i32 3}
 !6 = distinct !DISubprogram(name: "basic", linkageName: "basic", scope: null, file: !1, line: 1, type: !7, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !8)
 !7 = !DISubroutineType(types: !2)
 !8 = !{}
 !9 = !DILocation(line: 1, column: 1, scope: !6)
-!10 = distinct !{!10, !9, !9}
+!10 = distinct !{!10, !9, !11}
+!11 = !DILocation(line: 2, column: 2, scope: !12)
+!12 = !DILexicalBlock(scope: !6, file: !1, line: 3, column: 3)