Revert "[CGBlocks] Improve line info in backtraces containing *_helper_block"

[aprantl]

Summary

Block copy/destroy helpers are now linkonce_odr functions, meant to be uniqued, and thus attaching debug information from one translation unit (or even just from one instance of many inside one translation unit) would be misleading and wrong in the general case.

This effectively reverts commit 9c6b6826ce3720ca8bb9bd15f3abf71261e6b911.

rdar://problem/59137040

[vsk]

clang/test/CodeGenObjC/debug-info-blocks.m

26–30

Should the location on the ret instruction be artificial as well?

[aprantl]

Good catch, and non-obvious resolution.

[vsk]

Nice! Lgtm, thanks.

clang/lib/CodeGen/CGBlocks.cpp

CodeGenFunction::GenerateCopyHelperFunction(const CGBlockInfo &blockInfo) {
   SmallVector<QualType, 2> ArgTys;
   ArgTys.push_back(C.VoidPtrTy);
   ArgTys.push_back(C.VoidPtrTy);
   QualType FunctionTy = C.getFunctionType(ReturnTy, ArgTys, {});
 
   FunctionDecl *FD = FunctionDecl::Create(
       C, C.getTranslationUnitDecl(), SourceLocation(), SourceLocation(), II,
       FunctionTy, nullptr, SC_Static, false, false);
-
   setBlockHelperAttributesVisibility(blockInfo.CapturesNonExternalType, Fn, FI,
                                      CGM);
+  // This is necessary to avoid inheriting the previous line number.
+  FD->setImplicit();
   StartFunction(FD, ReturnTy, Fn, FI, args);
-  ApplyDebugLocation NL{*this, blockInfo.getBlockExpr()->getBeginLoc()};
+  auto AL = ApplyDebugLocation::CreateArtificial(*this);
+
   llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo();
 
   Address src = GetAddrOfLocalVar(&SrcDecl);
   src = Address(Builder.CreateLoad(src), blockInfo.BlockAlign);
   src = Builder.CreateBitCast(src, structPtrTy, "block.source");
 
   Address dst = GetAddrOfLocalVar(&DstDecl);
   dst = Address(Builder.CreateLoad(dst), blockInfo.BlockAlign);
CodeGenFunction::GenerateDestroyHelperFunction(const CGBlockInfo &blockInfo) {
   QualType FunctionTy = C.getFunctionType(ReturnTy, ArgTys, {});
 
   FunctionDecl *FD = FunctionDecl::Create(
       C, C.getTranslationUnitDecl(), SourceLocation(), SourceLocation(), II,
       FunctionTy, nullptr, SC_Static, false, false);
 
   setBlockHelperAttributesVisibility(blockInfo.CapturesNonExternalType, Fn, FI,
                                      CGM);
+  // This is necessary to avoid inheriting the previous line number.
+  FD->setImplicit();
   StartFunction(FD, ReturnTy, Fn, FI, args);
   markAsIgnoreThreadCheckingAtRuntime(Fn);
 
-  ApplyDebugLocation NL{*this, blockInfo.getBlockExpr()->getBeginLoc()};
+  auto AL = ApplyDebugLocation::CreateArtificial(*this);
 
   llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo();
 
   Address src = GetAddrOfLocalVar(&SrcDecl);
   src = Address(Builder.CreateLoad(src), blockInfo.BlockAlign);
   src = Builder.CreateBitCast(src, structPtrTy, "block");
 
   CodeGenFunction::RunCleanupsScope cleanups(*this);

clang/test/CodeGenObjC/debug-info-blocks.m

 
 // Test that we do emit scope info for the helper functions, and that the
 // parameters to these functions are marked as artificial (so the debugger
 // doesn't accidentally step into the function).
 // CHECK: define {{.*}} @__copy_helper_block_{{.*}}(i8* %0, i8* %1)
 // CHECK-NOT: ret
 // CHECK: call {{.*}}, !dbg ![[DBG_LINE:[0-9]+]]
 // CHECK-NOT: ret
-// CHECK: load {{.*}}, !dbg ![[COPY_LINE:[0-9]+]]
-// CHECK: ret void, !dbg ![[COPY_LINE]]
-// CHECK: define {{.*}} @__destroy_helper_block_{{.*}}(i8* %0)
+// CHECK: load {{.*}}, !dbg ![[DBG_LINE]]
+// CHECK: ret {{.*}}, !dbg ![[DBG_LINE]]
+// CHECK: define {{.*}} @__destroy_helper_block_{{.*}}(i8*
 // CHECK-NOT: ret
 // CHECK: load {{.*}}, !dbg ![[DESTROY_LINE:[0-9]+]]
-// CHECK: ret void, !dbg ![[DESTROY_LINE]]
+// CHECK: ret {{.*}}, !dbg ![[DESTROY_LINE]]
 
+// CHECK-DAG: [[DBG_LINE]] = !DILocation(line: 0, scope: ![[COPY_SP:[0-9]+]])
+// CHECK-DAG: [[COPY_SP]] = distinct !DISubprogram(name: "__copy_helper_block_
+// CHECK-DAG: [[DESTROY_LINE]] = !DILocation(line: 0, scope: ![[DESTROY_SP:[0-9]+]])
+// CHECK-DAG: [[DESTROY_SP]] = distinct !DISubprogram(name: "__destroy_helper_block_
 typedef unsigned int NSUInteger;
 
 @protocol NSObject
 @end  
    
 @interface NSObject <NSObject>
 - (id)init;
 + (id)alloc;
static void run(void (^block)(void))
     block();
 }
 
 @implementation A
 
 - (id)init
 {
     if ((self = [super init])) {
-      // CHECK-DAG: [[DBG_LINE]] = !DILocation(line: 0, scope: ![[COPY_SP:[0-9]+]])
-      // CHECK-DAG: [[COPY_LINE]] = !DILocation(line: [[@LINE+7]], scope: ![[COPY_SP:[0-9]+]])
-      // CHECK-DAG: [[COPY_SP]] = distinct !DISubprogram(name: "__copy_helper_block_8_32o"
-      // CHECK-DAG: [[DESTROY_LINE]] = !DILocation(line: [[@LINE+5]], scope: ![[DESTROY_SP:[0-9]+]])
-      // CHECK-DAG: [[DESTROY_SP]] = distinct !DISubprogram(name: "__destroy_helper_block_8_32o"
       // CHECK-DAG: !DILocalVariable(arg: 1, scope: ![[COPY_SP]], {{.*}}, flags: DIFlagArtificial)
       // CHECK-DAG: !DILocalVariable(arg: 2, scope: ![[COPY_SP]], {{.*}}, flags: DIFlagArtificial)
       // CHECK-DAG: !DILocalVariable(arg: 1, scope: ![[DESTROY_SP]], {{.*}}, flags: DIFlagArtificial)
       run(^{
           // CHECK-DAG: ![[SELF]] = !DILocalVariable(name: "self", scope:{{.*}}, line: [[@LINE+4]],
           // CHECK-DAG: ![[D]] = !DILocalVariable(name: "d", scope:{{.*}}, line: [[@LINE+1]],
           NSMutableDictionary *d = [[NSMutableDictionary alloc] init]; 
           ivar = 42 + (int)[d count];