Bugfix/Followup for r177086.
* Store the .block_descriptor (instead of self) in the alloca so we
  can guarantee that all captured variables are available at -O0.
* Add the missing OpDeref for the alloca.
rdar://problem/12767564

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178361 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGBlocks.cpp b/lib/CodeGen/CGBlocks.cpp
index 77e29bd..d702b85 100644
--- a/lib/CodeGen/CGBlocks.cpp
+++ b/lib/CodeGen/CGBlocks.cpp
@@ -1138,6 +1138,18 @@
   BlockPointer = Builder.CreateBitCast(blockAddr,
                                        blockInfo.StructureType->getPointerTo(),
                                        "block");
+  // At -O0 we generate an explicit alloca for the BlockPointer, so the RA
+  // won't delete the dbg.declare intrinsics for captured variables.
+  llvm::Value *BlockPointerDbgLoc = BlockPointer;
+  if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
+    // Allocate a stack slot for it, so we can point the debugger to it
+    llvm::AllocaInst *Alloca = CreateTempAlloca(BlockPointer->getType(),
+                                                "block.addr");
+    unsigned Align = getContext().getDeclAlign(&selfDecl).getQuantity();
+    Alloca->setAlignment(Align);
+    Builder.CreateAlignedStore(BlockPointer, Alloca, Align);
+    BlockPointerDbgLoc = Alloca;
+  }
 
   // If we have a C++ 'this' reference, go ahead and force it into
   // existence now.
@@ -1161,20 +1173,7 @@
       llvm::Value *selfAddr = Builder.CreateStructGEP(BlockPointer,
                                                       capture.getIndex(),
                                                       "block.captured-self");
-
-      // At -O0 we generate an explicit alloca for self to facilitate debugging.
-      if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
-	llvm::Value *load = Builder.CreateLoad(selfAddr);
-
-	// Allocate a stack slot for it, so we can generate debug info for it
-	llvm::AllocaInst *alloca = CreateTempAlloca(load->getType(),
-                                                   "block.captured-self.addr");
-        unsigned align = getContext().getDeclAlign(self).getQuantity();
-        alloca->setAlignment(align);
-	Builder.CreateAlignedStore(load, alloca, align);
-        LocalDeclMap[self] = alloca;
-      } else
-        LocalDeclMap[self] = selfAddr;
+      LocalDeclMap[self] = selfAddr;
     }
   }
 
@@ -1230,7 +1229,7 @@
           continue;
         }
 
-        DI->EmitDeclareOfBlockDeclRefVariable(variable, BlockPointer,
+        DI->EmitDeclareOfBlockDeclRefVariable(variable, BlockPointerDbgLoc,
                                               Builder, blockInfo);
       }
     }
diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index 2529ec8..a60d723 100644
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -2632,6 +2632,8 @@
 
   SmallVector<llvm::Value *, 9> addr;
   llvm::Type *Int64Ty = CGM.Int64Ty;
+  if (isa<llvm::AllocaInst>(Storage))
+    addr.push_back(llvm::ConstantInt::get(Int64Ty, llvm::DIBuilder::OpDeref));
   addr.push_back(llvm::ConstantInt::get(Int64Ty, llvm::DIBuilder::OpPlus));
   addr.push_back(llvm::ConstantInt::get(Int64Ty, offset.getQuantity()));
   if (isByRef) {
@@ -2653,6 +2655,7 @@
     DBuilder.createComplexVariable(llvm::dwarf::DW_TAG_auto_variable, 
                                    llvm::DIDescriptor(LexicalBlockStack.back()),
                                    VD->getName(), Unit, Line, Ty, addr);
+
   // Insert an llvm.dbg.declare into the current block.
   llvm::Instruction *Call =
     DBuilder.insertDeclare(Storage, D, Builder.GetInsertPoint());
@@ -2964,9 +2967,8 @@
         RepTy = llvm::DIType(cast<llvm::MDNode>(V));
     }
 
-    if (Ty.Verify() && Ty.isForwardDecl() && RepTy.Verify()) {
+    if (Ty.Verify() && Ty.isForwardDecl() && RepTy.Verify())
       Ty.replaceAllUsesWith(RepTy);
-    }
   }
 
   // We keep our own list of retained types, because we need to look
diff --git a/lib/CodeGen/CGDecl.cpp b/lib/CodeGen/CGDecl.cpp
index 5f388e0..d59c876 100644
--- a/lib/CodeGen/CGDecl.cpp
+++ b/lib/CodeGen/CGDecl.cpp
@@ -1578,7 +1578,7 @@
       LocalDeclMap[&D] = Arg;
       llvm::Value *LocalAddr = 0;
       if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
-        // Allocate a stack slot to let debug info survive the RA.
+        // Allocate a stack slot to let the debug info survive the RA.
         llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty),
                                                    D.getName() + ".addr");
         Alloc->setAlignment(getContext().getDeclAlign(&D).getQuantity());