[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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@309928 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Utils/CloneModule.cpp b/lib/Transforms/Utils/CloneModule.cpp
index d27cb45c7d7f5c12c3d87e0aa3a799a4b3a5c029..e5392b53050d34b55056d68a13febbcb6c6a31c1 100644 (file)
--- a/lib/Transforms/Utils/CloneModule.cpp
+++ b/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);
   }

diff --git a/unittests/Transforms/Utils/Cloning.cpp b/unittests/Transforms/Utils/Cloning.cpp
index 01ee9b841f869d0b09bdfa858f0883c94ecf04b1..fe4e2ba7e943140af9d3b0c9685dbc6cacb2d8b2 100644 (file)
--- a/unittests/Transforms/Utils/Cloning.cpp
+++ b/unittests/Transforms/Utils/Cloning.cpp
@@ -506,6 +506,19 @@ protected:
                                 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();
@@ -545,6 +558,52 @@ 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();