DebugInfo: Don't leak location information from one function into the prologue of...

CodeGenFunction objects aren't really designed to be reused for more
than one function, and doing so can leak debug info location information
from one function into the prologue of the next.

Add an assertion in to catch reuses of CodeGenFunction, which
surprisingly only caught the ObjC atomic getter/setter cases. Fix those
and add a test to demonstrate the issue.

The test is a bit slim, because we're just testing for the absence of a
debug location on the prologue instructions, which by itself probably
wouldn't be the end of the world - but the particular debug location
that was ending up there was for the previous function's last
instruction. This produced debug info for another function within this
function, which is something I'm trying to remove all cases of as its a
substantial source of bugs, especially around inlining (see r219215).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@219690 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/CGObjC.cpp b/lib/CodeGen/CGObjC.cpp
index b0c7cc9c7e226f7882001efd6bec74bb3e43be89..164df93e3140edc5cdb875c1530c1e3a1786e943 100644 (file)
--- a/lib/CodeGen/CGObjC.cpp
+++ b/lib/CodeGen/CGObjC.cpp
@@ -756,8 +756,8 @@ PropertyImplStrategy::PropertyImplStrategy(CodeGenModule &CGM,
 /// is illegal within a category.
 void CodeGenFunction::GenerateObjCGetter(ObjCImplementationDecl *IMP,
                                          const ObjCPropertyImplDecl *PID) {
-  llvm::Constant *AtomicHelperFn = 
-    GenerateObjCAtomicGetterCopyHelperFunction(PID);
+  llvm::Constant *AtomicHelperFn =
+      CodeGenFunction(CGM).GenerateObjCAtomicGetterCopyHelperFunction(PID);
   const ObjCPropertyDecl *PD = PID->getPropertyDecl();
   ObjCMethodDecl *OMD = PD->getGetterMethodDecl();
   assert(OMD && "Invalid call to generate getter (empty method)");
@@ -1285,8 +1285,8 @@ CodeGenFunction::generateObjCSetterBody(const ObjCImplementationDecl *classImpl,
 /// is illegal within a category.
 void CodeGenFunction::GenerateObjCSetter(ObjCImplementationDecl *IMP,
                                          const ObjCPropertyImplDecl *PID) {
-  llvm::Constant *AtomicHelperFn = 
-    GenerateObjCAtomicSetterCopyHelperFunction(PID);
+  llvm::Constant *AtomicHelperFn =
+      CodeGenFunction(CGM).GenerateObjCAtomicSetterCopyHelperFunction(PID);
   const ObjCPropertyDecl *PD = PID->getPropertyDecl();
   ObjCMethodDecl *OMD = PD->getSetterMethodDecl();
   assert(OMD && "Invalid call to generate setter (empty method)");

diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp
index 9f359185381715de075a2b64f12d1f778fc5716e..354939a23e2ba393a2173b289c426ddc9d18f3c3 100644 (file)
--- a/lib/CodeGen/CodeGenFunction.cpp
+++ b/lib/CodeGen/CodeGenFunction.cpp
@@ -36,7 +36,7 @@ using namespace CodeGen;
 CodeGenFunction::CodeGenFunction(CodeGenModule &cgm, bool suppressNewContext)
     : CodeGenTypeCache(cgm), CGM(cgm), Target(cgm.getTarget()),
       Builder(cgm.getModule().getContext(), llvm::ConstantFolder(),
-              CGBuilderInserterTy(this)),
+              CGBuilderInserterTy(this)), CurFn(nullptr),
       CapturedStmtInfo(nullptr), SanOpts(&CGM.getLangOpts().Sanitize),
       IsSanitizerScope(false), CurFuncIsThunk(false), AutoreleaseResult(false),
       SawAsmBlock(false), BlockInfo(nullptr), BlockPointer(nullptr),
@@ -565,6 +565,9 @@ void CodeGenFunction::StartFunction(GlobalDecl GD,
                                     const FunctionArgList &Args,
                                     SourceLocation Loc,
                                     SourceLocation StartLoc) {
+  assert(!CurFn &&
+         "Do not use a CodeGenFunction object for more than one function");
+
   const Decl *D = GD.getDecl();
 
   DidCallStackSave = false;

diff --git a/test/CodeGenObjCXX/property-objects.mm b/test/CodeGenObjCXX/property-objects.mm
index c79c280eddb1935b8da673998a02119adbb36ece..73ed21dcb7d8d87c0187e1e8370de30f49a6a5bb 100644 (file)
--- a/test/CodeGenObjCXX/property-objects.mm
+++ b/test/CodeGenObjCXX/property-objects.mm
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 %s -triple=x86_64-apple-darwin10 -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 %s -triple=x86_64-apple-darwin10 -emit-llvm -g -o - | FileCheck %s
 
 class S {
 public:
@@ -35,6 +35,11 @@ struct CGRect {
 // CHECK: call dereferenceable({{[0-9]+}}) %class.S* @_ZN1SaSERKS_
 // CHECK-NEXT: ret void
 
+// Don't attach debug locations to the prologue instructions. These were
+// leaking over from the previous function emission by accident.
+// CHECK: define internal void @"\01-[I setBounds:]"
+// CHECK-NOT: !dbg
+// CHECK: call void @llvm.dbg.declare
 - (void)setFrame:(CGRect)frameRect {}
 - (CGRect)frame {return bounds;}