Merging r309928:

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r309928 | ewancrawford | 2017-08-03 02:23:03 -0700 (Thu, 03 Aug 2017) | 56 lines

[Cloning] Move distinct GlobalVariable debug info metadata in CloneModule

Duplicating the distinct Subprogram and CU metadata nodes seems like the incorrect thing to do in CloneModule for GlobalVariable debug info. As it results in the scope of the GlobalVariable DI no longer being consistent with the rest of the module, and the new CU is absent from llvm.dbg.cu.

Fixed by adding RF_MoveDistinctMDs to MapMetadata flags for GlobalVariables.

Current unit test IR after clone:
```
@gv = global i32 1, comdat($comdat), !dbg !0, !type !5

define private void @f() comdat($comdat) personality void ()* @persfn !dbg !14 {

!llvm.dbg.cu = !{!10}

!0 = !DIGlobalVariableExpression(var: !1)
!1 = distinct !DIGlobalVariable(name: "gv", linkageName: "gv", scope: !2, file: !3, line: 1, type: !9, isLocal: false, isDefinition: true)
!2 = distinct !DISubprogram(name: "f", linkageName: "f", scope: null, file: !3, line: 4, type: !4, isLocal: true, isDefinition: true, scopeLine: 3, isOptimized: false, unit: !6, variables: !5)
!3 = !DIFile(filename: "filename.c", directory: "/file/dir/")
!4 = !DISubroutineType(types: !5)
!5 = !{}
!6 = distinct !DICompileUnit(language: DW_LANG_C99, file: !7, producer: "CloneModule", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !5, globals: !8)
!7 = !DIFile(filename: "filename.c", directory: "/file/dir")
!8 = !{!0}
!9 = !DIBasicType(tag: DW_TAG_unspecified_type, name: "decltype(nullptr)")
!10 = distinct !DICompileUnit(language: DW_LANG_C99, file: !7, producer: "CloneModule", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !5, globals: !11)
!11 = !{!12}
!12 = !DIGlobalVariableExpression(var: !13)
!13 = distinct !DIGlobalVariable(name: "gv", linkageName: "gv", scope: !14, file: !3, line: 1, type: !9, isLocal: false, isDefinition: true)
!14 = distinct !DISubprogram(name: "f", linkageName: "f", scope: null, file: !3, line: 4, type: !4, isLocal: true, isDefinition: true, scopeLine: 3, isOptimized: false, unit: !10, variables: !5)
```

Patched IR after clone:
```
@gv = global i32 1, comdat($comdat), !dbg !0, !type !5

define private void @f() comdat($comdat) personality void ()* @persfn !dbg !2 {

!llvm.dbg.cu = !{!6}

!0 = !DIGlobalVariableExpression(var: !1)
!1 = distinct !DIGlobalVariable(name: "gv", linkageName: "gv", scope: !2, file: !3, line: 1, type: !9, isLocal: false, isDefinition: true)
!2 = distinct !DISubprogram(name: "f", linkageName: "f", scope: null, file: !3, line: 4, type: !4, isLocal: true, isDefinition: true, scopeLine: 3, isOptimized: false, unit: !6, variables: !5)
!3 = !DIFile(filename: "filename.c", directory: "/file/dir/")
!4 = !DISubroutineType(types: !5)
!5 = !{}
!6 = distinct !DICompileUnit(language: DW_LANG_C99, file: !7, producer: "CloneModule", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !5, globals: !8)
!7 = !DIFile(filename: "filename.c", directory: "/file/dir")
!8 = !{!0}
!9 = !DIBasicType(tag: DW_TAG_unspecified_type, name: "decltype(nullptr)")
```

Reviewers: aprantl, probinson, dblaikie, echristo, loladiro
Reviewed By: aprantl
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D36082

------------------------------------------------------------------------

llvm-svn: 309965

llvm/lib/Transforms/Utils/CloneModule.cpp

@@ -132,7 +132,8 @@ std::unique_ptr<Module> llvm::CloneModule(
     SmallVector<std::pair<unsigned, MDNode *>, 1> MDs;
     I->getAllMetadata(MDs);
     for (auto MD : MDs)
-      GV->addMetadata(MD.first, *MapMetadata(MD.second, VMap));
+      GV->addMetadata(MD.first,
+                      *MapMetadata(MD.second, VMap, RF_MoveDistinctMDs));
 
     copyComdat(GV, &*I);
   }

llvm/unittests/Transforms/Utils/Cloning.cpp

@@ -507,6 +507,19 @@ class CloneModule : public ::testing::Test {
                                 DINode::FlagZero, false);
     F->setSubprogram(Subprogram);
 
+    // Create and assign DIGlobalVariableExpression to gv
+    auto GVExpression = DBuilder.createGlobalVariableExpression(
+        Subprogram, "gv", "gv", File, 1, DBuilder.createNullPtrType(), false);
+    GV->addDebugInfo(GVExpression);
+
+    // DIGlobalVariableExpression not attached to any global variable
+    auto Expr = DBuilder.createExpression(
+        ArrayRef<uint64_t>{dwarf::DW_OP_constu, 42U, dwarf::DW_OP_stack_value});
+
+    DBuilder.createGlobalVariableExpression(
+        Subprogram, "unattached", "unattached", File, 1,
+        DBuilder.createNullPtrType(), false, Expr);
+
     auto *Entry = BasicBlock::Create(C, "", F);
     IBuilder.SetInsertPoint(Entry);
     IBuilder.CreateRetVoid();
@@ -546,6 +559,52 @@ TEST_F(CloneModule, GlobalMetadata) {
   EXPECT_NE(nullptr, NewGV->getMetadata(LLVMContext::MD_type));
 }
 
+TEST_F(CloneModule, GlobalDebugInfo) {
+  GlobalVariable *NewGV = NewM->getGlobalVariable("gv");
+  EXPECT_TRUE(NewGV != nullptr);
+
+  // Find debug info expression assigned to global
+  SmallVector<DIGlobalVariableExpression *, 1> GVs;
+  NewGV->getDebugInfo(GVs);
+  EXPECT_EQ(GVs.size(), 1U);
+
+  DIGlobalVariableExpression *GVExpr = GVs[0];
+  DIGlobalVariable *GV = GVExpr->getVariable();
+  EXPECT_TRUE(GV != nullptr);
+
+  EXPECT_EQ(GV->getName(), "gv");
+  EXPECT_EQ(GV->getLine(), 1U);
+
+  // Assert that the scope of the debug info attached to
+  // global variable matches the cloned function.
+  DISubprogram *SP = NewM->getFunction("f")->getSubprogram();
+  EXPECT_TRUE(SP != nullptr);
+  EXPECT_EQ(GV->getScope(), SP);
+}
+
+TEST_F(CloneModule, CompileUnit) {
+  // Find DICompileUnit listed in llvm.dbg.cu
+  auto *NMD = NewM->getNamedMetadata("llvm.dbg.cu");
+  EXPECT_TRUE(NMD != nullptr);
+  EXPECT_EQ(NMD->getNumOperands(), 1U);
+
+  DICompileUnit *CU = dyn_cast<llvm::DICompileUnit>(NMD->getOperand(0));
+  EXPECT_TRUE(CU != nullptr);
+
+  // Assert this CU is consistent with the cloned function debug info
+  DISubprogram *SP = NewM->getFunction("f")->getSubprogram();
+  EXPECT_TRUE(SP != nullptr);
+  EXPECT_EQ(SP->getUnit(), CU);
+
+  // Check globals listed in CU have the correct scope
+  DIGlobalVariableExpressionArray GlobalArray = CU->getGlobalVariables();
+  EXPECT_EQ(GlobalArray.size(), 2U);
+  for (DIGlobalVariableExpression *GVExpr : GlobalArray) {
+    DIGlobalVariable *GV = GVExpr->getVariable();
+    EXPECT_EQ(GV->getScope(), SP);
+  }
+}
+
 TEST_F(CloneModule, Comdat) {
   GlobalVariable *NewGV = NewM->getGlobalVariable("gv");
   auto *CD = NewGV->getComdat();