[CodeGen] Fix an assert in CodeGenFunction::EmitFunctionEpilog

[ahatanak]

Summary

The assert near CGCall.cpp:2465 is triggered because QualType::isObjCRetainableType() is called on different types. In CodeGenFunction::StartFunction, it returns true because it is called on the typedef marked with attribute((NSObject)), whereas in CodeGenFunction::EmitFunctionEpilog it returns false because it's called on the canonical type.

To fix the assert, this patch changes the code in CodeGenFunction::EmitFunctionEpilog to get the function's return type from CodeGenFunction::CurCodeDecl or BlockInfo instead of from CGFunctionInfo.

[ahatanak]

Enclose the code with "#ifndef NDEBUG".

[ahatanak]

ping

[manmanren]

LGTM otherwise.

Cheers,
Manman

lib/CodeGen/CGCall.cpp

2468 ↗

(On Diff #47062)

Maybe add comments here on the if else block?

cfe/trunk/lib/CodeGen/CGCall.cpp

 //===--- CGCall.cpp - Encapsulate calling convention details --------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // These classes wrap the information about a call or function
 // definition used to handle ABI compliancy.
 //
 //===----------------------------------------------------------------------===//
 
 #include "CGCall.h"
 #include "ABIInfo.h"
+#include "CGBlocks.h"
 #include "CGCXXABI.h"
 #include "CGCleanup.h"
 #include "CodeGenFunction.h"
 #include "CodeGenModule.h"
 #include "TargetInfo.h"
 #include "clang/AST/Decl.h"
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/DeclObjC.h"
if (RetAI.getCoerceToType() == ConvertType(RetTy) &&
       Address V = emitAddressAtOffset(*this, ReturnValue, RetAI);
 
       RV = CreateCoercedLoad(V, RetAI.getCoerceToType(), *this);
     }
 
     // In ARC, end functions that return a retainable type with a call
     // to objc_autoreleaseReturnValue.
     if (AutoreleaseResult) {
+#ifndef NDEBUG
+      // Type::isObjCRetainabletype has to be called on a QualType that hasn't
+      // been stripped of the typedefs, so we cannot use RetTy here. Get the
+      // original return type of FunctionDecl, CurCodeDecl, and BlockDecl from
+      // CurCodeDecl or BlockInfo.
+      QualType RT;
+
+      if (auto *FD = dyn_cast<FunctionDecl>(CurCodeDecl))
+        RT = FD->getReturnType();
+      else if (auto *MD = dyn_cast<ObjCMethodDecl>(CurCodeDecl))
+        RT = MD->getReturnType();
+      else if (isa<BlockDecl>(CurCodeDecl))
+        RT = BlockInfo->BlockExpression->getFunctionType()->getReturnType();
+      else
+        llvm_unreachable("Unexpected function/method type");
+
       assert(getLangOpts().ObjCAutoRefCount &&
              !FI.isReturnsRetained() &&
-             RetTy->isObjCRetainableType());
+             RT->isObjCRetainableType());
+#endif
       RV = emitAutoreleaseOfResult(*this, RV);
     }
 
     break;
 
   case ABIArgInfo::Ignore:
     break;
 

cfe/trunk/test/CodeGenObjCXX/auto-release-result-assert.mm

+// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -emit-llvm -fblocks -fobjc-arc -o - %s | FileCheck %s
+
+// CHECK-LABEL: define %struct.S1* @_Z4foo1i(
+// CHECK: %[[CALL:[a-z0-9]+]] = call %struct.S1* @_Z4foo0i
+// CHECK: ret %struct.S1* %[[CALL]]
+
+// CHECK-LABEL: define %struct.S1* @_ZN2S22m1Ev(
+// CHECK: %[[CALL:[a-z0-9]+]] = call %struct.S1* @_Z4foo0i
+// CHECK: ret %struct.S1* %[[CALL]]
+
+// CHECK-LABEL: define internal %struct.S1* @Block1_block_invoke(
+// CHECK: %[[CALL:[a-z0-9]+]] = call %struct.S1* @_Z4foo0i
+// CHECK: ret %struct.S1* %[[CALL]]
+
+struct S1;
+
+typedef __attribute__((NSObject)) struct __attribute__((objc_bridge(id))) S1 * S1Ref;
+
+S1Ref foo0(int);
+
+struct S2 {
+  S1Ref m1();
+};
+
+S1Ref foo1(int a) {
+  return foo0(a);
+}
+
+S1Ref S2::m1() {
+  return foo0(0);
+}
+
+S1Ref (^Block1)(void) = ^{
+  return foo0(0);
+};