[cloning] Do not duplicate types when cloning functions

Summary:
This is an addon to the change rl304488 cloning fixes. (Originally rl304226 reverted rl304228 and reapplied rl304488 https://reviews.llvm.org/D33655)

rl304488 works great when DILocalVariables that comes from the inlined function has a 'unique-ed' type, but,
in the case when the variable type is distinct we will create a second DILocalVariable in the scope of the original function that was inlined.

Consider cloning of the following function:
```
define private void @f() !dbg !5 {
  %1 = alloca i32, !dbg !11
  call void @llvm.dbg.declare(metadata i32* %1, metadata !14, metadata !12), !dbg !18
  ret void, !dbg !18
}

!14 = !DILocalVariable(name: "inlined", scope: !15, file: !6, line: 5, type: !17) ; came from an inlined function
!15 = distinct !DISubprogram(name: "inlined", linkageName: "inlined", scope: null, file: !6, line: 8, type: !7, isLocal: true, isDefinition: true, scopeLine: 9, isOptimized: false, unit: !0, variables: !16)
!16 = !{!14}
!17 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "some_struct", size: 32, align: 32)
```

Without this fix, when function 'f' is cloned, we will create another DILocalVariable for "inlined", due to its type being distinct.

```
define private void @f.1() !dbg !23 {
  %1 = alloca i32, !dbg !26
  call void @llvm.dbg.declare(metadata i32* %1, metadata !28, metadata !12), !dbg !30
  ret void, !dbg !30
}

!14 = !DILocalVariable(name: "inlined", scope: !15, file: !6, line: 5, type: !17)
!15 = distinct !DISubprogram(name: "inlined", linkageName: "inlined", scope: null, file: !6, line: 8, type: !7, isLocal: true, isDefinition: true, scopeLine: 9, isOptimized: false, unit: !0, variables: !16)
!16 = !{!14}
!17 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "some_struct", size: 32, align: 32)
 ;
!28 = !DILocalVariable(name: "inlined", scope: !15, file: !6, line: 5, type: !29) ; OOPS second DILocalVariable
!29 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "some_struct", size: 32, align: 32)
```

Now we have two DILocalVariable for "inlined" within the same scope. This result in assert in AsmPrinter/DwarfDebug.h:131: void llvm::DbgVariable::addMMIEntry(const llvm::DbgVariable &): Assertion `V.Var == Var && "conflicting variable"' failed.
(Full example: See: https://bugs.llvm.org/show_bug.cgi?id=33492)

In this change we prevent duplication of types so that when a metadata for DILocalVariable is cloned it will get uniqued to the same metadate node as an original variable.

Reviewers: loladiro, dblaikie, aprantl, echristo

Reviewed By: loladiro

Subscribers: EricWF, llvm-commits

Differential Revision: https://reviews.llvm.org/D35106

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307418 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 11 insertions, 2 deletions

diff --git a/unittests/Transforms/Utils/Cloning.cpp b/unittests/Transforms/Utils/Cloning.cpp
index db3d10847cd8..72a91d144174 100644
--- a/unittests/Transforms/Utils/Cloning.cpp
+++ b/unittests/Transforms/Utils/Cloning.cpp
@@ -312,11 +312,16 @@ protected:
     DBuilder.insertDbgValueIntrinsic(AllocaContent, 0, Variable, E, DL,
                                      Entry);
     // Also create an inlined variable.
+    // Create a distinct struct type that we should not duplicate during
+    // cloning).
+    auto *StructType = DICompositeType::getDistinct(
+        C, dwarf::DW_TAG_structure_type, "some_struct", nullptr, 0, nullptr,
+        nullptr, 32, 32, 0, DINode::FlagZero, nullptr, 0, nullptr, nullptr);
     auto *InlinedSP =
         DBuilder.createFunction(CU, "inlined", "inlined", File, 8, FuncType,
                                 true, true, 9, DINode::FlagZero, false);
     auto *InlinedVar =
-        DBuilder.createAutoVariable(InlinedSP, "inlined", File, 5, IntType, true);
+        DBuilder.createAutoVariable(InlinedSP, "inlined", File, 5, StructType, true);
     auto *Scope = DBuilder.createLexicalBlock(
         DBuilder.createLexicalBlockFile(InlinedSP, File), File, 1, 1);
     auto InlinedDL =
@@ -426,7 +431,11 @@ TEST_F(CloneFunc, DebugIntrinsics) {
       EXPECT_EQ(NewFunc, cast<AllocaInst>(NewIntrin->getAddress())->
                          getParent()->getParent());
 
-      if (!OldIntrin->getDebugLoc()->getInlinedAt()) {
+      if (OldIntrin->getDebugLoc()->getInlinedAt()) {
+        // Inlined variable should refer to the same DILocalVariable as in the
+        // Old Function
+        EXPECT_EQ(OldIntrin->getVariable(), NewIntrin->getVariable());
+      } else {
         // Old variable must belong to the old function.
         EXPECT_EQ(OldFunc->getSubprogram(),
                   cast<DISubprogram>(OldIntrin->getVariable()->getScope()));