r316704 - [CGBlocks] Improve line info in backtraces containing *_helper_block

[Vedant Kumar via cfe-commits]

Author: vedantk
Date: Thu Oct 26 14:27:24 2017
New Revision: 316704

URL: http://llvm.org/viewvc/llvm-project?rev=316704&view=rev
Log:
[CGBlocks] Improve line info in backtraces containing *_helper_block

Instead of only setting a non-zero debug location on the return
instruction in *_helper_block functions, set a proper location on all
instructions within these functions. Pick the start location of the
block literal expr for maximum clarity.

The debugger does not step into *_helper_block functions during normal
single-stepping because we mark their parameters as artificial. This is
what we want (the functions are implicitly generated and uninteresting
to most users). The stepping behavior is unchanged by this patch.

rdar://32907581

Differential Revision: https://reviews.llvm.org/D39310

Modified:
    cfe/trunk/lib/CodeGen/CGBlocks.cpp
    cfe/trunk/test/CodeGenObjC/debug-info-blocks.m

Modified: cfe/trunk/lib/CodeGen/CGBlocks.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGBlocks.cpp?rev=316704&r1=316703&r2=316704&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGBlocks.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGBlocks.cpp Thu Oct 26 14:27:24 2017
@@ -1644,10 +1644,8 @@ CodeGenFunction::GenerateCopyHelperFunct
 
   CGM.SetInternalFunctionAttributes(nullptr, Fn, FI);
 
-  auto NL = ApplyDebugLocation::CreateEmpty(*this);
   StartFunction(FD, C.VoidTy, Fn, FI, args);
-  // Create a scope with an artificial location for the body of this function.
-  auto AL = ApplyDebugLocation::CreateArtificial(*this);
+  ApplyDebugLocation NL{*this, blockInfo.getBlockExpr()->getLocStart()};
   llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo();
 
   Address src = GetAddrOfLocalVar(&SrcDecl);
@@ -1816,10 +1814,8 @@ CodeGenFunction::GenerateDestroyHelperFu
 
   CGM.SetInternalFunctionAttributes(nullptr, Fn, FI);
 
-  // Create a scope with an artificial location for the body of this function.
-  auto NL = ApplyDebugLocation::CreateEmpty(*this);
   StartFunction(FD, C.VoidTy, Fn, FI, args);
-  auto AL = ApplyDebugLocation::CreateArtificial(*this);
+  ApplyDebugLocation NL{*this, blockInfo.getBlockExpr()->getLocStart()};
 
   llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo();
 

Modified: cfe/trunk/test/CodeGenObjC/debug-info-blocks.m
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenObjC/debug-info-blocks.m?rev=316704&r1=316703&r2=316704&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenObjC/debug-info-blocks.m (original)
+++ cfe/trunk/test/CodeGenObjC/debug-info-blocks.m Thu Oct 26 14:27:24 2017
@@ -10,23 +10,20 @@
 // CHECK-NEXT: call void @llvm.dbg.declare(metadata <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>** %[[ALLOCA]], metadata ![[SELF:[0-9]+]], metadata !{{.*}})
 // CHECK-NEXT: call void @llvm.dbg.declare(metadata %1** %d, metadata ![[D:[0-9]+]], metadata !{{.*}})
 
-// rdar://problem/14386148
-// Test that we don't emit bogus line numbers for the helper functions.
-// Test that we do emit scope info for the helper functions.
+// 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*, i8*)
 // 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*)
 // CHECK-NOT: ret
 // CHECK: load {{.*}}, !dbg ![[DESTROY_LINE:[0-9]+]]
+// CHECK: ret void, !dbg ![[DESTROY_LINE]]
 
-// CHECK-DAG: [[DBG_LINE]] = !DILocation(line: 0, scope: ![[COPY_SP:[0-9]+]])
-// CHECK-DAG: [[COPY_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
@@ -60,6 +57,14 @@ static void run(void (^block)(void))
 - (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_"
+      // CHECK-DAG: [[DESTROY_LINE]] = !DILocation(line: [[@LINE+5]], scope: ![[DESTROY_SP:[0-9]+]])
+      // CHECK-DAG: [[DESTROY_SP]] = distinct !DISubprogram(name: "__destroy_helper_block_"
+      // 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]],