3 files changed, 22 insertions, 14 deletions
diff --git a/clang/lib/CodeGen/CGBlocks.cpp b/clang/lib/CodeGen/CGBlocks.cpp
index e7743fa0c65..2915dabe541 100644
--- a/clang/lib/CodeGen/CGBlocks.cpp
+++ b/clang/lib/CodeGen/CGBlocks.cpp
@@ -1294,19 +1294,19 @@ void CodeGenFunction::setBlockContextParameter(const ImplicitParamDecl *D,
   assert(BlockInfo && "not emitting prologue of block invocation function?!");
 
   llvm::Value *localAddr = nullptr;
-  // Allocate a stack slot like for any local variable to guarantee optimal
-  // debug info at -O0. The mem2reg pass will eliminate it when optimizing.
-  Address alloc = CreateMemTemp(D->getType(), D->getName() + ".addr");
-  Builder.CreateStore(arg, alloc);
-  localAddr = Builder.CreateLoad(alloc);
+  if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
+    // Allocate a stack slot to let the debug info survive the RA.
+    Address alloc = CreateMemTemp(D->getType(), D->getName() + ".addr");
+    Builder.CreateStore(arg, alloc);
+    localAddr = Builder.CreateLoad(alloc);
+  }
 
   if (CGDebugInfo *DI = getDebugInfo()) {
     if (CGM.getCodeGenOpts().getDebugInfo() >=
         codegenoptions::LimitedDebugInfo) {
       DI->setLocation(D->getLocation());
-      DI->EmitDeclareOfBlockLiteralArgVariable(
-          *BlockInfo, D->getName(), argNum,
-          cast<llvm::AllocaInst>(alloc.getPointer()), Builder);
+      DI->EmitDeclareOfBlockLiteralArgVariable(*BlockInfo, arg, argNum,
+                                               localAddr, Builder);
     }
   }
 
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 3e4acd208f6..a73e4a98b3c 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -3694,9 +3694,9 @@ bool operator<(const BlockLayoutChunk &l, const BlockLayoutChunk &r) {
 }
 
 void CGDebugInfo::EmitDeclareOfBlockLiteralArgVariable(const CGBlockInfo &block,
-                                                       StringRef Name,
+                                                       llvm::Value *Arg,
                                                        unsigned ArgNo,
-                                                       llvm::AllocaInst *Alloca,
+                                                       llvm::Value *LocalAddr,
                                                        CGBuilderTy &Builder) {
   assert(DebugKind >= codegenoptions::LimitedDebugInfo);
   ASTContext &C = CGM.getContext();
@@ -3828,11 +3828,19 @@ void CGDebugInfo::EmitDeclareOfBlockLiteralArgVariable(const CGBlockInfo &block,
 
   // Create the descriptor for the parameter.
   auto *debugVar = DBuilder.createParameterVariable(
-      scope, Name, ArgNo, tunit, line, type,
+      scope, Arg->getName(), ArgNo, tunit, line, type,
       CGM.getLangOpts().Optimize, flags);
 
+  if (LocalAddr) {
+    // Insert an llvm.dbg.value into the current block.
+    DBuilder.insertDbgValueIntrinsic(
+        LocalAddr, debugVar, DBuilder.createExpression(),
+        llvm::DebugLoc::get(line, column, scope, CurInlinedAt),
+        Builder.GetInsertBlock());
+  }
+
   // Insert an llvm.dbg.declare into the current block.
-  DBuilder.insertDeclare(Alloca, debugVar, DBuilder.createExpression(),
+  DBuilder.insertDeclare(Arg, debugVar, DBuilder.createExpression(),
                          llvm::DebugLoc::get(line, column, scope, CurInlinedAt),
                          Builder.GetInsertBlock());
 }
diff --git a/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
index 4f7b7f2a0d9..36de231f05f 100644
--- a/clang/lib/CodeGen/CGDebugInfo.h
+++ b/clang/lib/CodeGen/CGDebugInfo.h
@@ -398,8 +398,8 @@ public:
   /// Emit call to \c llvm.dbg.declare for the block-literal argument
   /// to a block invocation function.
   void EmitDeclareOfBlockLiteralArgVariable(const CGBlockInfo &block,
-                                            StringRef Name, unsigned ArgNo,
-                                            llvm::AllocaInst *LocalAddr,
+                                            llvm::Value *Arg, unsigned ArgNo,
+                                            llvm::Value *LocalAddr,
                                             CGBuilderTy &Builder);
 
   /// Emit information about a global variable.