4 files changed, 33 insertions, 4 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index f78ca2c03b4..77860c0bd10 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -730,6 +730,8 @@ void DwarfDebug::beginModule() {
 
   const Module *M = MMI->getModule();
 
+  FunctionDIs = makeSubprogramMap(*M);
+
   // If module has named metadata anchors then use them, otherwise scan the
   // module using debug info finder to collect debug info.
   NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
@@ -1415,6 +1417,10 @@ void DwarfDebug::beginFunction(const MachineFunction *MF) {
   if (!MMI->hasDebugInfo())
     return;
 
+  auto DI = FunctionDIs.find(MF->getFunction());
+  if (DI == FunctionDIs.end())
+    return;
+
   // Grab the lexical scopes for the function, if we don't have any of those
   // then we're not going to be able to do anything.
   LScopes.initialize(*MF);
@@ -1430,6 +1436,14 @@ void DwarfDebug::beginFunction(const MachineFunction *MF) {
   // belongs to so that we add to the correct per-cu line table in the
   // non-asm case.
   LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
+  // FnScope->getScopeNode() and DI->second should represent the same function,
+  // though they may not be the same MDNode due to inline functions merged in
+  // LTO where the debug info metadata still differs (either due to distinct
+  // written differences - two versions of a linkonce_odr function
+  // written/copied into two separate files, or some sub-optimal metadata that
+  // isn't structurally identical (see: file path/name info from clang, which
+  // includes the directory of the cpp file being built, even when the file name
+  // is absolute (such as an <> lookup header)))
   DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
   assert(TheCU && "Unable to find compile unit!");
   if (Asm->OutStreamer.hasRawTextSupport())
@@ -1527,7 +1541,8 @@ void DwarfDebug::endFunction(const MachineFunction *MF) {
     assert(CurFn == MF);
   assert(CurFn != nullptr);
 
-  if (!MMI->hasDebugInfo() || LScopes.empty()) {
+  if (!MMI->hasDebugInfo() || LScopes.empty() ||
+      !FunctionDIs.count(MF->getFunction())) {
     // If we don't have a lexical scope for this function then there will
     // be a hole in the range information. Keep note of this by setting the
     // previously used section to nullptr.
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
index f2aa80845a0..ffe4843b987 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -330,6 +330,8 @@ class DwarfDebug : public AsmPrinterHandler {
   DwarfAccelTable AccelNamespace;
   DwarfAccelTable AccelTypes;
 
+  DenseMap<const Function *, DISubprogram> FunctionDIs;
+
   MCDwarfDwoLineTable *getDwoLineTable(const DwarfCompileUnit &);
 
   void addScopeVariable(LexicalScope *LS, DbgVariable *Var);
diff --git a/llvm/lib/CodeGen/LiveDebugVariables.cpp b/llvm/lib/CodeGen/LiveDebugVariables.cpp
index 388f58fde2a..7d5646bebfa 100644
--- a/llvm/lib/CodeGen/LiveDebugVariables.cpp
+++ b/llvm/lib/CodeGen/LiveDebugVariables.cpp
@@ -329,12 +329,13 @@ class LDVImpl {
   void computeIntervals();
 
 public:
-  LDVImpl(LiveDebugVariables *ps) : pass(*ps), EmitDone(false),
-                                    ModifiedMF(false) {}
+  LDVImpl(LiveDebugVariables *ps)
+      : pass(*ps), MF(nullptr), EmitDone(false), ModifiedMF(false) {}
   bool runOnMachineFunction(MachineFunction &mf);
 
   /// clear - Release all memory.
   void clear() {
+    MF = nullptr;
     userValues.clear();
     virtRegToEqClass.clear();
     userVarMap.clear();
@@ -693,11 +694,11 @@ void LDVImpl::computeIntervals() {
 }
 
 bool LDVImpl::runOnMachineFunction(MachineFunction &mf) {
+  clear();
   MF = &mf;
   LIS = &pass.getAnalysis<LiveIntervals>();
   MDT = &pass.getAnalysis<MachineDominatorTree>();
   TRI = mf.getTarget().getRegisterInfo();
-  clear();
   LS.initialize(mf);
   DEBUG(dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "
                << mf.getName() << " **********\n");
@@ -712,6 +713,8 @@ bool LDVImpl::runOnMachineFunction(MachineFunction &mf) {
 bool LiveDebugVariables::runOnMachineFunction(MachineFunction &mf) {
   if (!EnableLDV)
     return false;
+  if (!FunctionDIs.count(mf.getFunction()))
+    return false;
   if (!pImpl)
     pImpl = new LDVImpl(this);
   return static_cast<LDVImpl*>(pImpl)->runOnMachineFunction(mf);
@@ -974,6 +977,8 @@ void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
 
 void LDVImpl::emitDebugValues(VirtRegMap *VRM) {
   DEBUG(dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n");
+  if (!MF)
+    return;
   const TargetInstrInfo *TII = MF->getTarget().getInstrInfo();
   for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
     DEBUG(userValues[i]->print(dbgs(), &MF->getTarget()));
@@ -988,6 +993,10 @@ void LiveDebugVariables::emitDebugValues(VirtRegMap *VRM) {
     static_cast<LDVImpl*>(pImpl)->emitDebugValues(VRM);
 }
 
+bool LiveDebugVariables::doInitialization(Module &M) {
+  FunctionDIs = makeSubprogramMap(M);
+  return Pass::doInitialization(M);
+}
 
 #ifndef NDEBUG
 void LiveDebugVariables::dump() {
diff --git a/llvm/lib/CodeGen/LiveDebugVariables.h b/llvm/lib/CodeGen/LiveDebugVariables.h
index bb6743547e3..7ec0d17e42d 100644
--- a/llvm/lib/CodeGen/LiveDebugVariables.h
+++ b/llvm/lib/CodeGen/LiveDebugVariables.h
@@ -22,6 +22,7 @@
 #define LLVM_CODEGEN_LIVEDEBUGVARIABLES_H
 
 #include "llvm/ADT/ArrayRef.h"
+#include "llvm/IR/DebugInfo.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 
 namespace llvm {
@@ -32,6 +33,7 @@ class VirtRegMap;
 
 class LiveDebugVariables : public MachineFunctionPass {
   void *pImpl;
+  DenseMap<const Function*, DISubprogram> FunctionDIs;
 public:
   static char ID; // Pass identification, replacement for typeid
 
@@ -64,6 +66,7 @@ private:
   bool runOnMachineFunction(MachineFunction &) override;
   void releaseMemory() override;
   void getAnalysisUsage(AnalysisUsage &) const override;
+  bool doInitialization(Module &) override;
 
 };