Revert r302469 "Make it illegal for two Functions to point to the same DISubprogram"

This caused PR32977.

Original commit message:

> Make it illegal for two Functions to point to the same DISubprogram
>
> As recently discussed on llvm-dev [1], this patch makes it illegal for
> two Functions to point to the same DISubprogram and updates
> FunctionCloner to also clone the debug info of a function to conform
> to the new requirement. To simplify the implementation it also factors
> out the creation of inlineAt locations from the Inliner into a
> general-purpose utility in DILocation.
>
> [1] http://lists.llvm.org/pipermail/llvm-dev/2017-May/112661.html
> <rdar://problem/31926379>
>
> Differential Revision: https://reviews.llvm.org/D32975

llvm-svn: 302533

4 files changed, 46 insertions, 156 deletions

diff --git a/llvm/lib/IR/DebugLoc.cpp b/llvm/lib/IR/DebugLoc.cpp
index 11beb22ddca..f31074a7ad4 100644
--- a/llvm/lib/IR/DebugLoc.cpp
+++ b/llvm/lib/IR/DebugLoc.cpp
@@ -8,7 +8,6 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/IR/DebugLoc.h"
-#include "llvm/IR/IntrinsicInst.h"
 #include "LLVMContextImpl.h"
 #include "llvm/IR/DebugInfo.h"
 using namespace llvm;
@@ -67,119 +66,6 @@ DebugLoc DebugLoc::get(unsigned Line, unsigned Col, const MDNode *Scope,
                          const_cast<MDNode *>(InlinedAt));
 }
 
-DebugLoc DebugLoc::appendInlinedAt(DebugLoc DL, DILocation *InlinedAt,
-                                   LLVMContext &Ctx,
-                                   DenseMap<const MDNode *, MDNode *> &Cache,
-                                   bool ReplaceLast) {
-  SmallVector<DILocation *, 3> InlinedAtLocations;
-  DILocation *Last = InlinedAt;
-  DILocation *CurInlinedAt = DL;
-
-  // Gather all the inlined-at nodes.
-  while (DILocation *IA = CurInlinedAt->getInlinedAt()) {
-    // Skip any we've already built nodes for.
-    if (auto *Found = Cache[IA]) {
-      Last = cast<DILocation>(Found);
-      break;
-    }
-
-    if (ReplaceLast && !IA->getInlinedAt())
-      break;
-    InlinedAtLocations.push_back(IA);
-    CurInlinedAt = IA;
-  }
-
-  // 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 DILocation *MD : reverse(InlinedAtLocations))
-    Cache[MD] = Last = DILocation::getDistinct(
-        Ctx, MD->getLine(), MD->getColumn(), MD->getScope(), Last);
-
-  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 || !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::getDistinct(
-        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/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 3b68d636587..65e12456249 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -267,9 +267,6 @@ class Verifier : public InstVisitor<Verifier>, VerifierSupport {
   /// \brief Keep track of the metadata nodes that have been checked already.
   SmallPtrSet<const Metadata *, 32> MDNodes;
 
-  /// Keep track which DISubprogram is attached to which function.
-  DenseMap<const DISubprogram *, const Function *> DISubprogramAttachments;
-
   /// Track all DICompileUnits visited.
   SmallPtrSet<const Metadata *, 2> CUVisited;
 
@@ -389,7 +386,7 @@ public:
     verifyCompileUnits();
 
     verifyDeoptimizeCallingConvs();
-    DISubprogramAttachments.clear();
+
     return !Broken;
   }
 
@@ -2088,19 +2085,13 @@ void Verifier::visitFunction(const Function &F) {
       switch (I.first) {
       default:
         break;
-      case LLVMContext::MD_dbg: {
+      case LLVMContext::MD_dbg:
         ++NumDebugAttachments;
         AssertDI(NumDebugAttachments == 1,
                  "function must have a single !dbg attachment", &F, I.second);
         AssertDI(isa<DISubprogram>(I.second),
                  "function !dbg attachment must be a subprogram", &F, I.second);
-        auto *SP = cast<DISubprogram>(I.second);
-        const Function *&AttachedTo = DISubprogramAttachments[SP];
-        AssertDI(!AttachedTo || AttachedTo == &F,
-                 "DISubprogram attached to more than one function", SP, &F);
-        AttachedTo = &F;
         break;
-      }
       case LLVMContext::MD_prof:
         ++NumProfAttachments;
         Assert(NumProfAttachments == 1,
diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index 4aa26fd14fe..d5124ac8901 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -41,7 +41,6 @@ BasicBlock *llvm::CloneBasicBlock(const BasicBlock *BB,
                                   ValueToValueMapTy &VMap,
                                   const Twine &NameSuffix, Function *F,
                                   ClonedCodeInfo *CodeInfo) {
-  DenseMap<const MDNode *, MDNode *> Cache;
   BasicBlock *NewBB = BasicBlock::Create(BB->getContext(), "", F);
   if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix);
 
@@ -51,9 +50,6 @@ BasicBlock *llvm::CloneBasicBlock(const BasicBlock *BB,
   for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end();
        II != IE; ++II) {
     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);
@@ -124,28 +120,12 @@ void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
 
   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(),
-          NewFunc->getName(), 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);
-  }
+  for (auto MD : MDs)
+    NewFunc->addMetadata(
+        MD.first,
+        *MapMetadata(MD.second, VMap,
+                     ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges,
+                     TypeMapper, Materializer));
 
   // 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
diff --git a/llvm/lib/Transforms/Utils/InlineFunction.cpp b/llvm/lib/Transforms/Utils/InlineFunction.cpp
index bafccaadd5e..6d56e08af99 100644
--- a/llvm/lib/Transforms/Utils/InlineFunction.cpp
+++ b/llvm/lib/Transforms/Utils/InlineFunction.cpp
@@ -1302,6 +1302,41 @@ static bool hasLifetimeMarkers(AllocaInst *AI) {
   return false;
 }
 
+/// Rebuild the entire inlined-at chain for this instruction so that the top of
+/// the chain now is inlined-at the new call site.
+static DebugLoc
+updateInlinedAtInfo(const DebugLoc &DL, DILocation *InlinedAtNode,
+                    LLVMContext &Ctx,
+                    DenseMap<const DILocation *, DILocation *> &IANodes) {
+  SmallVector<DILocation *, 3> InlinedAtLocations;
+  DILocation *Last = InlinedAtNode;
+  DILocation *CurInlinedAt = DL;
+
+  // Gather all the inlined-at nodes
+  while (DILocation *IA = CurInlinedAt->getInlinedAt()) {
+    // Skip any we've already built nodes for
+    if (DILocation *Found = IANodes[IA]) {
+      Last = Found;
+      break;
+    }
+
+    InlinedAtLocations.push_back(IA);
+    CurInlinedAt = IA;
+  }
+
+  // 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 DILocation *MD : reverse(InlinedAtLocations)) {
+    Last = IANodes[MD] = DILocation::getDistinct(
+        Ctx, MD->getLine(), MD->getColumn(), MD->getScope(), Last);
+  }
+
+  // And finally create the normal location for this instruction, referring to
+  // the new inlined-at chain.
+  return DebugLoc::get(DL.getLine(), DL.getCol(), DL.getScope(), Last);
+}
+
 /// Return the result of AI->isStaticAlloca() if AI were moved to the entry
 /// block. Allocas used in inalloca calls and allocas of dynamic array size
 /// cannot be static.
@@ -1329,16 +1364,14 @@ static void fixupLineNumbers(Function *Fn, Function::iterator FI,
   // Cache the inlined-at nodes as they're built so they are reused, without
   // this every instruction's inlined-at chain would become distinct from each
   // other.
-  DenseMap<const MDNode *, MDNode *> IANodes;
+  DenseMap<const DILocation *, DILocation *> IANodes;
 
   for (; FI != Fn->end(); ++FI) {
     for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
          BI != BE; ++BI) {
       if (DebugLoc DL = BI->getDebugLoc()) {
-        auto IA = DebugLoc::appendInlinedAt(DL, InlinedAtNode, BI->getContext(),
-                                            IANodes);
-        auto IDL = DebugLoc::get(DL.getLine(), DL.getCol(), DL.getScope(), IA);
-        BI->setDebugLoc(IDL);
+        BI->setDebugLoc(
+            updateInlinedAtInfo(DL, InlinedAtNode, BI->getContext(), IANodes));
         continue;
       }