Reapply "[Cloning] Take another pass at properly cloning debug info"

This was rL304226, reverted in 304228 due to a clang assertion failure
on the build bots. That problem should have been addressed by clang
commit rL304470.

llvm-svn: 304488

1 files changed, 43 insertions, 28 deletions

diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index 1ec3d0d4963..1c1a75c111e 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -37,10 +37,10 @@
 using namespace llvm;
 
 /// See comments in Cloning.h.
-BasicBlock *llvm::CloneBasicBlock(const BasicBlock *BB,
-                                  ValueToValueMapTy &VMap,
+BasicBlock *llvm::CloneBasicBlock(const BasicBlock *BB, ValueToValueMapTy &VMap,
                                   const Twine &NameSuffix, Function *F,
-                                  ClonedCodeInfo *CodeInfo) {
+                                  ClonedCodeInfo *CodeInfo,
+                                  DebugInfoFinder *DIFinder) {
   DenseMap<const MDNode *, MDNode *> Cache;
   BasicBlock *NewBB = BasicBlock::Create(BB->getContext(), "", F);
   if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix);
@@ -50,10 +50,11 @@ BasicBlock *llvm::CloneBasicBlock(const BasicBlock *BB,
   // Loop over all instructions, and copy them over.
   for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end();
        II != IE; ++II) {
+
+    if (DIFinder && F->getParent() && II->getDebugLoc())
+      DIFinder->processLocation(*F->getParent(), II->getDebugLoc().get());
+
     Instruction *NewInst = II->clone();
-    if (F && F->getSubprogram())
-      DebugLoc::reparentDebugInfo(*NewInst, BB->getParent()->getSubprogram(),
-                                  F->getSubprogram(), Cache);
     if (II->hasName())
       NewInst->setName(II->getName()+NameSuffix);
     NewBB->getInstList().push_back(NewInst);
@@ -122,31 +123,38 @@ void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
       AttributeList::get(NewFunc->getContext(), OldAttrs.getFnAttributes(),
                          OldAttrs.getRetAttributes(), NewArgAttrs));
 
+  bool MustCloneSP =
+      OldFunc->getParent() && OldFunc->getParent() == NewFunc->getParent();
+  DISubprogram *SP = OldFunc->getSubprogram();
+  if (SP) {
+    assert(!MustCloneSP || ModuleLevelChanges);
+    // Add mappings for some DebugInfo nodes that we don't want duplicated
+    // even if they're distinct.
+    auto &MD = VMap.MD();
+    MD[SP->getUnit()].reset(SP->getUnit());
+    MD[SP->getType()].reset(SP->getType());
+    MD[SP->getFile()].reset(SP->getFile());
+    // If we're not cloning into the same module, no need to clone the
+    // subprogram
+    if (!MustCloneSP)
+      MD[SP].reset(SP);
+  }
+
   SmallVector<std::pair<unsigned, MDNode *>, 1> MDs;
   OldFunc->getAllMetadata(MDs);
   for (auto MD : MDs) {
-    MDNode *NewMD;
-    bool MustCloneSP =
-        (MD.first == LLVMContext::MD_dbg && OldFunc->getParent() &&
-         OldFunc->getParent() == NewFunc->getParent());
-    if (MustCloneSP) {
-      auto *SP = cast<DISubprogram>(MD.second);
-      NewMD = DISubprogram::getDistinct(
-          NewFunc->getContext(), SP->getScope(), SP->getName(),
-          SP->getLinkageName(), SP->getFile(), SP->getLine(), SP->getType(),
-          SP->isLocalToUnit(), SP->isDefinition(), SP->getScopeLine(),
-          SP->getContainingType(), SP->getVirtuality(), SP->getVirtualIndex(),
-          SP->getThisAdjustment(), SP->getFlags(), SP->isOptimized(),
-          SP->getUnit(), SP->getTemplateParams(), SP->getDeclaration(),
-          SP->getVariables(), SP->getThrownTypes());
-    } else
-      NewMD =
-          MapMetadata(MD.second, VMap,
-                      ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges,
-                      TypeMapper, Materializer);
-    NewFunc->addMetadata(MD.first, *NewMD);
+    NewFunc->addMetadata(
+        MD.first,
+        *MapMetadata(MD.second, VMap,
+                     ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges,
+                     TypeMapper, Materializer));
   }
 
+  // When we remap instructions, we want to avoid duplicating inlined
+  // DISubprograms, so record all subprograms we find as we duplicate
+  // instructions and then freeze them in the MD map.
+  DebugInfoFinder DIFinder;
+
   // Loop over all of the basic blocks in the function, cloning them as
   // appropriate.  Note that we save BE this way in order to handle cloning of
   // recursive functions into themselves.
@@ -156,7 +164,8 @@ void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
     const BasicBlock &BB = *BI;
 
     // Create a new basic block and copy instructions into it!
-    BasicBlock *CBB = CloneBasicBlock(&BB, VMap, NameSuffix, NewFunc, CodeInfo);
+    BasicBlock *CBB = CloneBasicBlock(&BB, VMap, NameSuffix, NewFunc, CodeInfo,
+                                      SP ? &DIFinder : nullptr);
 
     // Add basic block mapping.
     VMap[&BB] = CBB;
@@ -178,6 +187,12 @@ void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
       Returns.push_back(RI);
   }
 
+  for (DISubprogram *ISP : DIFinder.subprograms()) {
+    if (ISP != SP) {
+      VMap.MD()[ISP].reset(ISP);
+    }
+  }
+
   // Loop over all of the instructions in the function, fixing up operand
   // references as we go.  This uses VMap to do all the hard work.
   for (Function::iterator BB =
@@ -226,7 +241,7 @@ Function *llvm::CloneFunction(Function *F, ValueToValueMapTy &VMap,
     }
 
   SmallVector<ReturnInst*, 8> Returns;  // Ignore returns cloned.
-  CloneFunctionInto(NewF, F, VMap, /*ModuleLevelChanges=*/false, Returns, "",
+  CloneFunctionInto(NewF, F, VMap, F->getSubprogram() != nullptr, Returns, "",
                     CodeInfo);
 
   return NewF;