1 files changed, 51 insertions, 5 deletions

diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index c1ef655be4b..9b28f837d70 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -1053,9 +1053,27 @@ static bool LdStHasDebugValue(DILocalVariable *DIVar, DIExpression *DIExpr,
   return false;
 }
 
+/// See if there is a dbg.value intrinsic for DIVar for the PHI node.
+static bool PhiHasDebugValue(DILocalVariable *DIVar, 
+                             DIExpression *DIExpr,
+                             PHINode *APN) {
+  // Since we can't guarantee that the original dbg.declare instrinsic
+  // is removed by LowerDbgDeclare(), we need to make sure that we are
+  // not inserting the same dbg.value intrinsic over and over.
+  DbgValueList DbgValues;
+  FindAllocaDbgValues(DbgValues, APN);
+  for (auto DVI : DbgValues) {
+    assert (DVI->getValue() == APN);
+    assert (DVI->getOffset() == 0);
+    if ((DVI->getVariable() == DIVar) && (DVI->getExpression() == DIExpr))
+      return true;
+  }
+  return false;
+}
+
 /// Inserts a llvm.dbg.value intrinsic before a store to an alloca'd value
 /// that has an associated llvm.dbg.decl intrinsic.
-bool llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
+void llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
                                            StoreInst *SI, DIBuilder &Builder) {
   auto *DIVar = DDI->getVariable();
   auto *DIExpr = DDI->getExpression();
@@ -1096,19 +1114,18 @@ bool llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
   } else if (!LdStHasDebugValue(DIVar, DIExpr, SI))
     Builder.insertDbgValueIntrinsic(SI->getOperand(0), 0, DIVar, DIExpr,
                                     DDI->getDebugLoc(), SI);
-  return true;
 }
 
 /// Inserts a llvm.dbg.value intrinsic before a load of an alloca'd value
 /// that has an associated llvm.dbg.decl intrinsic.
-bool llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
+void llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
                                            LoadInst *LI, DIBuilder &Builder) {
   auto *DIVar = DDI->getVariable();
   auto *DIExpr = DDI->getExpression();
   assert(DIVar && "Missing variable");
 
   if (LdStHasDebugValue(DIVar, DIExpr, LI))
-    return true;
+    return;
 
   // We are now tracking the loaded value instead of the address. In the
   // future if multi-location support is added to the IR, it might be
@@ -1117,7 +1134,26 @@ bool llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
   Instruction *DbgValue = Builder.insertDbgValueIntrinsic(
       LI, 0, DIVar, DIExpr, DDI->getDebugLoc(), (Instruction *)nullptr);
   DbgValue->insertAfter(LI);
-  return true;
+}
+
+/// Inserts a llvm.dbg.value intrinsic after a phi 
+/// that has an associated llvm.dbg.decl intrinsic.
+void llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
+                                           PHINode *APN, DIBuilder &Builder) {
+  auto *DIVar = DDI->getVariable();
+  auto *DIExpr = DDI->getExpression();
+  assert(DIVar && "Missing variable");
+
+  if (PhiHasDebugValue(DIVar, DIExpr, APN))
+    return;
+
+  auto BB = APN->getParent();
+  auto InsertionPt = BB->getFirstInsertionPt();
+  if (InsertionPt != BB->end()) {
+    Instruction *DbgValue = Builder.insertDbgValueIntrinsic(
+        APN, 0, DIVar, DIExpr, DDI->getDebugLoc(), (Instruction *)nullptr);
+    DbgValue->insertBefore(&*InsertionPt);
+  }
 }
 
 /// Determine whether this alloca is either a VLA or an array.
@@ -1187,6 +1223,16 @@ DbgDeclareInst *llvm::FindAllocaDbgDeclare(Value *V) {
   return nullptr;
 }
 
+/// FindAllocaDbgValues - Finds the llvm.dbg.value intrinsics describing the
+/// alloca 'V', if any.
+void llvm::FindAllocaDbgValues(DbgValueList &DbgValues, Value *V) {
+  if (auto *L = LocalAsMetadata::getIfExists(V))
+    if (auto *MDV = MetadataAsValue::getIfExists(V->getContext(), L))
+      for (User *U : MDV->users())
+        if (DbgValueInst *DVI = dyn_cast<DbgValueInst>(U))
+          DbgValues.push_back(DVI);
+}
+
 static void DIExprAddDeref(SmallVectorImpl<uint64_t> &Expr) {
   Expr.push_back(dwarf::DW_OP_deref);
 }