llvm-project/clang/test/CodeGenObjC/exceptions.m

// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -fobjc-fragile-abi -emit-llvm -fexceptions -fobjc-exceptions -O2 -o - %s | FileCheck %s
//
// <rdar://problem/7471679> [irgen] [eh] Exception code built with clang (x86_64) crashes

// Just check that we don't emit any dead blocks.
@interface NSArray @end
void f0() {
  @try {
    @try {
      @throw @"a";
    } @catch(NSArray *e) {
    }
  } @catch (id e) {
  }
}

// CHECK: define void @f1()
void f1() {
  extern void foo(void);

  while (1) {
    // CHECK:      call void @objc_exception_try_enter
    // CHECK-NEXT: getelementptr
    // CHECK-NEXT: call i32 @_setjmp(
    // CHECK-NEXT: icmp
    // CHECK-NEXT: br i1
    @try {
    // CHECK:      call void asm sideeffect "", "*m"
    // CHECK-NEXT: call void @foo()
      foo();
    // CHECK-NEXT: call void @objc_exception_try_exit

    // CHECK:      call void asm sideeffect "", "=*m"
    } @finally {
      break;
    }
  }
}

// Test that modifications to local variables are respected under
// optimization.  rdar://problem/8160285

// CHECK: define i32 @f2()
int f2() {
  extern void foo(void);

  // CHECK:        [[X:%.*]] = alloca i32
  // CHECK:        store i32 5, i32* [[X]]
  int x = 0;
  x += 5;

  // CHECK:        [[SETJMP:%.*]] = call i32 @_setjmp
  // CHECK-NEXT:   [[CAUGHT:%.*]] = icmp eq i32 [[SETJMP]], 0
  // CHECK-NEXT:   br i1 [[CAUGHT]]
  @try {
    // CHECK: store i32 6, i32* [[X]]
    x++;
    // CHECK-NEXT: call void asm sideeffect "", "*m,*m"(i32* [[X]]
    // CHECK-NEXT: call void @foo()
    // CHECK-NEXT: call void @objc_exception_try_exit
    // CHECK-NEXT: [[T:%.*]] = load i32* [[X]]
    foo();
  } @catch (id) {
    // Landing pad.  Note that we elide the re-enter.
    // CHECK:      call void asm sideeffect "", "=*m,=*m"(i32* [[X]]
    // CHECK-NEXT: call i8* @objc_exception_extract
    // CHECK-NEXT: [[T1:%.*]] = load i32* [[X]]
    // CHECK-NEXT: [[T2:%.*]] = add nsw i32 [[T1]], -1

    // This store is dead.
    // CHECK-NEXT: store i32 [[T2]], i32* [[X]]
    x--;
  }

  return x;
}

// Test that the cleanup destination is saved when entering a finally
// block.  rdar://problem/8293901
// CHECK: define void @f3()
void f3() {
  extern void f3_helper(int, int*);

  // CHECK:      [[X:%.*]] = alloca i32
  // CHECK:      store i32 0, i32* [[X]]
  int x = 0;

  // CHECK:      call void @objc_exception_try_enter(
  // CHECK:      call i32 @_setjmp
  // CHECK-NEXT: icmp eq
  // CHECK-NEXT: br i1

  @try {
    // CHECK:    call void @f3_helper(i32 0, i32* [[X]])
    // CHECK:    call void @objc_exception_try_exit(
    f3_helper(0, &x);
  } @finally {
    // CHECK:    [[DEST1:%.*]] = phi i32 [ 0, {{%.*}} ], [ 3, {{%.*}} ]
    // CHECK:    call void @objc_exception_try_enter
    // CHECK:    call i32 @_setjmp
    @try {
      // CHECK:  call void @f3_helper(i32 1, i32* [[X]])
      // CHECK:  call void @objc_exception_try_exit(
      f3_helper(1, &x);
    } @finally {
      // CHECK:  [[DEST2:%.*]] = phi i32 [ 0, {{%.*}} ], [ 5, {{%.*}} ]
      // CHECK:  call void @f3_helper(i32 2, i32* [[X]])
      f3_helper(2, &x);

      // This loop is large enough to dissuade the optimizer from just
      // duplicating the finally block.
      while (x) f3_helper(3, &x);

      // This is a switch or maybe some chained branches, but relying
      // on a specific result from the optimizer is really unstable.
      // CHECK:  [[DEST2]]
    }

      // This is a switch or maybe some chained branches, but relying
      // on a specific result from the optimizer is really unstable.
    // CHECK:    [[DEST1]]
  }

  // CHECK:      call void @f3_helper(i32 4, i32* [[X]])
  // CHECK-NEXT: ret void
  f3_helper(4, &x);
}

// rdar://problem/8440970
void f4() {
  extern void f4_help(int);

  // CHECK: define void @f4()
  // CHECK:      [[EXNDATA:%.*]] = alloca [[EXNDATA_T:%.*]], align
  // CHECK:      call void @objc_exception_try_enter([[EXNDATA_T]]* [[EXNDATA]])
  // CHECK:      call i32 @_setjmp
  @try {
  // CHECK:      call void @f4_help(i32 0)
    f4_help(0);

  // The finally cleanup has two threaded entrypoints after optimization:

  // finally.no-call-exit:  Predecessor is when the catch throws.
  // CHECK:      call i8* @objc_exception_extract([[EXNDATA_T]]* [[EXNDATA]])
  // CHECK-NEXT: call void @f4_help(i32 2)
  // CHECK-NEXT: br label
  //   -> rethrow

  // finally.call-exit:  Predecessors are the @try and @catch fallthroughs
  // as well as the no-match case in the catch mechanism.  The i1 is whether
  // to rethrow and should be true only in the last case.
  // CHECK:      phi i1
  // CHECK-NEXT: phi i8*
  // CHECK-NEXT: call void @objc_exception_try_exit([[EXNDATA_T]]* [[EXNDATA]])
  // CHECK-NEXT: call void @f4_help(i32 2)
  // CHECK-NEXT: br i1
  //   -> ret, rethrow

  // ret:
  // CHECK:      ret void

  // Catch mechanism:
  // CHECK:      call i8* @objc_exception_extract([[EXNDATA_T]]* [[EXNDATA]])
  // CHECK-NEXT: call void @objc_exception_try_enter([[EXNDATA_T]]* [[EXNDATA]])
  // CHECK:      call i32 @_setjmp
  //   -> next, finally.no-call-exit
  // CHECK:      call i32 @objc_exception_match
  //   -> finally.call-exit, match
  } @catch (NSArray *a) {
  // match:
  // CHECK:      call void @f4_help(i32 1)
  // CHECK-NEXT: br label
  //   -> finally.call-exit
    f4_help(1);
  } @finally {
    f4_help(2);
  }

  // rethrow:
  // CHECK:      phi i8*
  // CHECK-NEXT: call void @objc_exception_throw(i8*
  // CHECK-NEXT: unreachable
}