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

At least one build bot is complaining. Will investigate after lunch.

llvm-svn: 304228

3 files changed, 110 insertions, 44 deletions

diff --git a/llvm/lib/IR/DebugLoc.cpp b/llvm/lib/IR/DebugLoc.cpp
index 0485fece7c4..b7e3f0c6779 100644
--- a/llvm/lib/IR/DebugLoc.cpp
+++ b/llvm/lib/IR/DebugLoc.cpp
@@ -99,6 +99,87 @@ DebugLoc DebugLoc::appendInlinedAt(DebugLoc DL, DILocation *InlinedAt,
   return Last;
 }
 
+/// Reparent \c Scope from \c OrigSP to \c NewSP.
+static DIScope *reparentScope(LLVMContext &Ctx, DIScope *Scope,
+                              DISubprogram *OrigSP, DISubprogram *NewSP,
+                              DenseMap<const MDNode *, MDNode *> &Cache) {
+  SmallVector<DIScope *, 3> ScopeChain;
+  DIScope *Last = NewSP;
+  DIScope *CurScope = Scope;
+  do {
+    if (auto *SP = dyn_cast<DISubprogram>(CurScope)) {
+      // Don't rewrite this scope chain if it doesn't lead to the replaced SP.
+      if (SP != OrigSP)
+        return Scope;
+      Cache.insert({OrigSP, NewSP});
+      break;
+    }
+    if (auto *Found = Cache[CurScope]) {
+      Last = cast<DIScope>(Found);
+      break;
+    }
+    ScopeChain.push_back(CurScope);
+  } while ((CurScope = CurScope->getScope().resolve()));
+
+  // Starting from the top, rebuild the nodes to point to the new inlined-at
+  // location (then rebuilding the rest of the chain behind it) and update the
+  // map of already-constructed inlined-at nodes.
+  for (const DIScope *MD : reverse(ScopeChain)) {
+    if (auto *LB = dyn_cast<DILexicalBlock>(MD))
+      Cache[MD] = Last = DILexicalBlock::getDistinct(
+          Ctx, Last, LB->getFile(), LB->getLine(), LB->getColumn());
+    else if (auto *LB = dyn_cast<DILexicalBlockFile>(MD))
+      Cache[MD] = Last = DILexicalBlockFile::getDistinct(
+          Ctx, Last, LB->getFile(), LB->getDiscriminator());
+    else
+      llvm_unreachable("illegal parent scope");
+  }
+  return Last;
+}
+
+void DebugLoc::reparentDebugInfo(Instruction &I, DISubprogram *OrigSP,
+                                 DISubprogram *NewSP,
+                                 DenseMap<const MDNode *, MDNode *> &Cache) {
+  auto DL = I.getDebugLoc();
+  if (!OrigSP || !NewSP || OrigSP == NewSP || !DL)
+    return;
+
+  // Reparent the debug location.
+  auto &Ctx = I.getContext();
+  DILocation *InlinedAt = DL->getInlinedAt();
+  if (InlinedAt) {
+    while (auto *IA = InlinedAt->getInlinedAt())
+      InlinedAt = IA;
+    auto NewScope =
+        reparentScope(Ctx, InlinedAt->getScope(), OrigSP, NewSP, Cache);
+    InlinedAt =
+        DebugLoc::get(InlinedAt->getLine(), InlinedAt->getColumn(), NewScope);
+  }
+  I.setDebugLoc(
+      DebugLoc::get(DL.getLine(), DL.getCol(),
+                    reparentScope(Ctx, DL->getScope(), OrigSP, NewSP, Cache),
+                    DebugLoc::appendInlinedAt(DL, InlinedAt, Ctx, Cache,
+                                              ReplaceLastInlinedAt)));
+
+  // Fix up debug variables to point to NewSP.
+  auto reparentVar = [&](DILocalVariable *Var) {
+    return DILocalVariable::get(
+        Ctx,
+        cast<DILocalScope>(
+            reparentScope(Ctx, Var->getScope(), OrigSP, NewSP, Cache)),
+        Var->getName(), Var->getFile(), Var->getLine(), Var->getType(),
+        Var->getArg(), Var->getFlags(), Var->getAlignInBits());
+  };
+  if (auto *DbgValue = dyn_cast<DbgValueInst>(&I)) {
+    auto *Var = DbgValue->getVariable();
+    I.setOperand(2, MetadataAsValue::get(Ctx, reparentVar(Var)));
+  } else if (auto *DbgDeclare = dyn_cast<DbgDeclareInst>(&I)) {
+    auto *Var = DbgDeclare->getVariable();
+    I.setOperand(1, MetadataAsValue::get(Ctx, reparentVar(Var)));
+  }
+}
+
+
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 LLVM_DUMP_METHOD void DebugLoc::dump() const {
   if (!Loc)
diff --git a/llvm/lib/Transforms/Coroutines/CoroSplit.cpp b/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
index c8e671e6a6e..cd549e4be28 100644
--- a/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
+++ b/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
@@ -228,7 +228,7 @@ static Function *createClone(Function &F, Twine Suffix, coro::Shape &Shape,
 
   SmallVector<ReturnInst *, 4> Returns;
 
-  CloneFunctionInto(NewF, &F, VMap, /*ModuleLevelChanges=*/true, Returns);
+  CloneFunctionInto(NewF, &F, VMap, /*ModuleLevelChanges=*/false, Returns);
 
   // Remove old returns.
   for (ReturnInst *Return : Returns)
diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index 1c1a75c111e..1ec3d0d4963 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,
-                                  DebugInfoFinder *DIFinder) {
+                                  ClonedCodeInfo *CodeInfo) {
   DenseMap<const MDNode *, MDNode *> Cache;
   BasicBlock *NewBB = BasicBlock::Create(BB->getContext(), "", F);
   if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix);
@@ -50,11 +50,10 @@ BasicBlock *llvm::CloneBasicBlock(const BasicBlock *BB, ValueToValueMapTy &VMap,
   // 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);
@@ -123,38 +122,31 @@ 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) {
-    NewFunc->addMetadata(
-        MD.first,
-        *MapMetadata(MD.second, VMap,
-                     ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges,
-                     TypeMapper, Materializer));
+    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);
   }
 
-  // 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.
@@ -164,8 +156,7 @@ 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,
-                                      SP ? &DIFinder : nullptr);
+    BasicBlock *CBB = CloneBasicBlock(&BB, VMap, NameSuffix, NewFunc, CodeInfo);
 
     // Add basic block mapping.
     VMap[&BB] = CBB;
@@ -187,12 +178,6 @@ 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 =
@@ -241,7 +226,7 @@ Function *llvm::CloneFunction(Function *F, ValueToValueMapTy &VMap,
     }
 
   SmallVector<ReturnInst*, 8> Returns;  // Ignore returns cloned.
-  CloneFunctionInto(NewF, F, VMap, F->getSubprogram() != nullptr, Returns, "",
+  CloneFunctionInto(NewF, F, VMap, /*ModuleLevelChanges=*/false, Returns, "",
                     CodeInfo);
 
   return NewF;