Remove all uses of DIFlagBlockByrefStruct

This patch removes the last reason why DIFlagBlockByrefStruct from
Clang by directly implementing the drilling into the member type done
in DwarfDebug::DbgVariable::getType() into the frontend.

rdar://problem/31629055

Differential Revision: https://reviews.llvm.org/D51807

llvm-svn: 341842

clang/lib/CodeGen/CGDebugInfo.cpp

@@ -3565,9 +3565,9 @@ void CGDebugInfo::EmitFunctionEnd(CGBuilderTy &Builder, llvm::Function *Fn) {
     DBuilder.finalizeSubprogram(Fn->getSubprogram());
 }
 
-llvm::DIType *CGDebugInfo::EmitTypeForVarWithBlocksAttr(const VarDecl *VD,
+CGDebugInfo::BlockByRefType
+CGDebugInfo::EmitTypeForVarWithBlocksAttr(const VarDecl *VD,
                                           uint64_t *XOffset) {
-
   SmallVector<llvm::Metadata *, 5> EltTys;
   QualType FType;
   uint64_t FieldSize, FieldOffset;
@@ -3619,23 +3619,21 @@ llvm::DIType *CGDebugInfo::EmitTypeForVarWithBlocksAttr(const VarDecl *VD,
   }
 
   FType = Type;
-  llvm::DIType *FieldTy = getOrCreateType(FType, Unit);
+  llvm::DIType *WrappedTy = getOrCreateType(FType, Unit);
   FieldSize = CGM.getContext().getTypeSize(FType);
   FieldAlign = CGM.getContext().toBits(Align);
 
   *XOffset = FieldOffset;
-  FieldTy = DBuilder.createMemberType(Unit, VD->getName(), Unit, 0, FieldSize,
+  llvm::DIType *FieldTy = DBuilder.createMemberType(
-                                      FieldAlign, FieldOffset,
+      Unit, VD->getName(), Unit, 0, FieldSize, FieldAlign, FieldOffset,
-                                      llvm::DINode::FlagZero, FieldTy);
+      llvm::DINode::FlagZero, WrappedTy);
   EltTys.push_back(FieldTy);
   FieldOffset += FieldSize;
 
   llvm::DINodeArray Elements = DBuilder.getOrCreateArray(EltTys);
-
+  return {DBuilder.createStructType(Unit, "", Unit, 0, FieldOffset, 0,
-  llvm::DINode::DIFlags Flags = llvm::DINode::FlagBlockByrefStruct;
+                                    llvm::DINode::FlagZero, nullptr, Elements),
-
+          WrappedTy};
-  return DBuilder.createStructType(Unit, "", Unit, 0, FieldOffset, 0, Flags,
-                                   nullptr, Elements);
 }
 
 llvm::DILocalVariable *CGDebugInfo::EmitDeclare(const VarDecl *VD,
@@ -3656,7 +3654,7 @@ llvm::DILocalVariable *CGDebugInfo::EmitDeclare(const VarDecl *VD,
   llvm::DIType *Ty;
   uint64_t XOffset = 0;
   if (VD->hasAttr<BlocksAttr>())
-    Ty = EmitTypeForVarWithBlocksAttr(VD, &XOffset);
+    Ty = EmitTypeForVarWithBlocksAttr(VD, &XOffset).WrappedType;
   else
     Ty = getOrCreateType(VD->getType(), Unit);
 
@@ -3794,7 +3792,7 @@ void CGDebugInfo::EmitDeclareOfBlockDeclRefVariable(
   llvm::DIFile *Unit = getOrCreateFile(VD->getLocation());
   llvm::DIType *Ty;
   if (isByRef)
-    Ty = EmitTypeForVarWithBlocksAttr(VD, &XOffset);
+    Ty = EmitTypeForVarWithBlocksAttr(VD, &XOffset).WrappedType;
   else
     Ty = getOrCreateType(VD->getType(), Unit);
 
@@ -3987,10 +3985,10 @@ void CGDebugInfo::EmitDeclareOfBlockLiteralArgVariable(const CGBlockInfo &block,
     if (capture->isByRef()) {
       TypeInfo PtrInfo = C.getTypeInfo(C.VoidPtrTy);
       auto Align = PtrInfo.AlignIsRequired ? PtrInfo.Align : 0;
-
+      // FIXME: This recomputes the layout of the BlockByRefWrapper.
-      // FIXME: this creates a second copy of this type!
       uint64_t xoffset;
-      fieldType = EmitTypeForVarWithBlocksAttr(variable, &xoffset);
+      fieldType =
+          EmitTypeForVarWithBlocksAttr(variable, &xoffset).BlockByRefWrapper;
       fieldType = DBuilder.createPointerType(fieldType, PtrInfo.Width);
       fieldType = DBuilder.createMemberType(tunit, name, tunit, line,
                                             PtrInfo.Width, Align, offsetInBits,

clang/lib/CodeGen/CGDebugInfo.h

@@ -491,8 +491,15 @@ private:
                                      llvm::Optional<unsigned> ArgNo,
                                      CGBuilderTy &Builder);
 
+  struct BlockByRefType {
+    /// The wrapper struct used inside the __block_literal struct.
+    llvm::DIType *BlockByRefWrapper;
+    /// The type as it appears in the source code.
+    llvm::DIType *WrappedType;
+  };
+
   /// Build up structure info for the byref.  See \a BuildByRefType.
-  llvm::DIType *EmitTypeForVarWithBlocksAttr(const VarDecl *VD,
+  BlockByRefType EmitTypeForVarWithBlocksAttr(const VarDecl *VD,
                                               uint64_t *OffSet);
 
   /// Get context info for the DeclContext of \p Decl.

clang/test/CodeGenObjC/block-byref-debuginfo.m

@@ -1,16 +1,35 @@
 // RUN: %clang_cc1 -fblocks -fobjc-arc -fobjc-runtime-has-weak -debug-info-kind=limited -triple x86_64-apple-darwin -emit-llvm %s -o - | FileCheck %s
 
-// rdar://problem/14386148
+// CHECK: !DILocalVariable(name: "foo", {{.*}}type: ![[FOOTY:[0-9]+]])
+// CHECK: ![[FOOTY]] = {{.*}}!DICompositeType({{.*}}, name: "Foo"
+
+// CHECK-NOT: DIFlagBlockByrefStruct
+// CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "__block_literal_1",
+// CHECK-SAME:             size: 320, elements: ![[BL_ELTS:[0-9]+]])
+// CHECK: ![[BL_ELTS]] = !{{.*}}![[WFOO:[0-9]+]]}
+
 // Test that the foo is aligned at an 8 byte boundary in the DWARF
 // expression (256) that locates it inside of the byref descriptor:
-// CHECK: !DIDerivedType(tag: DW_TAG_member, name: "foo",
+// CHECK: ![[WFOO]] = !DIDerivedType(tag: DW_TAG_member, name: "foo",
-// CHECK-NOT:            line:
+// CHECK-SAME:                       baseType: ![[PTR:[0-9]+]]
-// CHECK-SAME:           offset: 256
+// CHECK-SAME:                       offset: 256)
+
+// CHECK: ![[PTR]] = !DIDerivedType(tag: DW_TAG_pointer_type,
+// CHECK-SAME:                      baseType: ![[WRAPPER:[0-9]+]]
+// CHECK: ![[WRAPPER]] = !DICompositeType(tag: DW_TAG_structure_type, scope:
+// CHECK:                                 elements: ![[WR_ELTS:[0-9]+]])
+// CHECK: ![[WR_ELTS]] = !{{.*}}![[WFOO:[0-9]+]]}
+// CHECK: ![[WFOO]] = !DIDerivedType(tag: DW_TAG_member, name: "foo",
+// CHECK-SAME:                       baseType: ![[FOOTY]]
+
+// CHECK: !DILocalVariable(name: "foo", {{.*}}type: ![[FOOTY]])
+
 
 struct Foo {
   unsigned char *data;
 };
 int func() {
   __attribute__((__blocks__(byref))) struct Foo foo;
+  ^{ foo.data = 0; }();
   return 0;
 }