Debug info for blocks: Fix a bug caught by the Verifier.

When emitting nested block definitions, the insert-at-point variant of
DIBuilder::insertDeclare() could be called with the insertion point set
to the end-of-BasicBlock sentinel, causing the parent pointer of the
CallInst to be set to the intentionally bogus value of the sentinel.

Fixed by conditionally invoking the correct version of insertDeclare().
rdar://problem/19034882

llvm-svn: 222487

4 files changed, 37 insertions, 5 deletions

diff --git a/clang/lib/CodeGen/CGBlocks.cpp b/clang/lib/CodeGen/CGBlocks.cpp
index 2fe93f87ccc..f088cd6746d 100644
--- a/clang/lib/CodeGen/CGBlocks.cpp
+++ b/clang/lib/CodeGen/CGBlocks.cpp
@@ -1243,7 +1243,9 @@ CodeGenFunction::GenerateBlockFunction(GlobalDecl GD,
         }
 
         DI->EmitDeclareOfBlockDeclRefVariable(variable, BlockPointerDbgLoc,
-                                              Builder, blockInfo);
+                                              Builder, blockInfo,
+                                              entry_ptr == entry->end()
+                                              ? nullptr : entry_ptr);
       }
     }
     // Recover location if it was changed in the above loop.
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index e91b6fdf298..416f69e7c31 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -2940,7 +2940,7 @@ llvm::DIType CGDebugInfo::CreateSelfType(const QualType &QualTy,
 
 void CGDebugInfo::EmitDeclareOfBlockDeclRefVariable(
     const VarDecl *VD, llvm::Value *Storage, CGBuilderTy &Builder,
-    const CGBlockInfo &blockInfo) {
+    const CGBlockInfo &blockInfo, llvm::Instruction *InsertPoint) {
   assert(DebugKind >= CodeGenOptions::LimitedDebugInfo);
   assert(!LexicalBlockStack.empty() && "Region stack mismatch, stack empty!");
 
@@ -2998,8 +2998,11 @@ void CGDebugInfo::EmitDeclareOfBlockDeclRefVariable(
                                    VD->getName(), Unit, Line, Ty);
 
   // Insert an llvm.dbg.declare into the current block.
-  llvm::Instruction *Call = DBuilder.insertDeclare(
-      Storage, D, DBuilder.createExpression(addr), Builder.GetInsertPoint());
+  llvm::Instruction *Call = InsertPoint ?
+      DBuilder.insertDeclare(Storage, D, DBuilder.createExpression(addr),
+                             InsertPoint)
+    : DBuilder.insertDeclare(Storage, D, DBuilder.createExpression(addr),
+                             Builder.GetInsertBlock());
   Call->setDebugLoc(
       llvm::DebugLoc::get(Line, Column, LexicalBlockStack.back()));
 }
diff --git a/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
index 49d99aac264..89d592e7d2e 100644
--- a/clang/lib/CodeGen/CGDebugInfo.h
+++ b/clang/lib/CodeGen/CGDebugInfo.h
@@ -263,7 +263,8 @@ public:
   void EmitDeclareOfBlockDeclRefVariable(const VarDecl *variable,
                                          llvm::Value *storage,
                                          CGBuilderTy &Builder,
-                                         const CGBlockInfo &blockInfo);
+                                         const CGBlockInfo &blockInfo,
+                                         llvm::Instruction *InsertPoint = 0);
 
   /// EmitDeclareOfArgVariable - Emit call to llvm.dbg.declare for an argument
   /// variable declaration.
diff --git a/clang/test/CodeGenObjC/debug-info-nested-blocks.m b/clang/test/CodeGenObjC/debug-info-nested-blocks.m
new file mode 100644
index 00000000000..5817b86302c
--- /dev/null
+++ b/clang/test/CodeGenObjC/debug-info-nested-blocks.m
@@ -0,0 +1,26 @@
+// RUN: %clang_cc1 -emit-llvm -gdwarf-2 -fblocks -o - -x objective-c %s| FileCheck %s
+// This code triggered a bug where a dbg.declare intrinsic ended up with the
+// wrong parent and subsequently failed the Verifier.
+void baz(id b);
+void fub(id block);
+int foo(void);
+void bar(void) {
+  fub(^() {
+      id a;
+      id b = [a bar:^(int e){}];
+      if (b) {
+        ^() {
+            if ((0 && foo()) ? 1 : 0) {
+              baz([a aMessage]);
+            }
+        };
+      }
+  });
+}
+
+// Verify that debug info for BlockPointerDbgLoc is emitted for the
+// innermost block.
+//
+// CHECK: define {{.*}}void @__bar_block_invoke_3(i8* %.block_descriptor)
+// CHECK: %[[BLOCKADDR:.*]] = alloca <{{.*}}>*, align 8
+// CHECK: call void @llvm.dbg.declare(metadata !{{.*}}%[[BLOCKADDR]]