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MS ABI: Don't push destructor cleanups for aggregate parameters in thunks 

The target method of the thunk will perform the cleanup.  This can't be
tested in 32-bit x86 yet because passing something by value would create
an inalloca, and we refuse to generate broken code for that.

llvm-svn: 213976
This commit is contained in:
Reid Kleckner 2014-07-25 21:39:46 +00:00
parent a822d94f57
commit 19819446eb
5 changed files with 43 additions and 11 deletions
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4
clang/lib/CodeGen/CGDecl.cpp
View File

@ -1656,7 +1656,9 @@ void CodeGenFunction::EmitParmDecl(const VarDecl &D, llvm::Value *Arg,
DeclPtr = Arg->getType() == IRTy ? Arg : Builder.CreateBitCast(Arg, IRTy,
D.getName());
// Push a destructor cleanup for this parameter if the ABI requires it.
if (!IsScalar &&
// Don't push a cleanup in a thunk for a method that will also emit a
// cleanup.
if (!IsScalar && !CurFuncIsThunk &&
getTarget().getCXXABI().areArgsDestroyedLeftToRightInCallee()) {
const CXXRecordDecl *RD = Ty->getAsCXXRecordDecl();
if (RD && RD->hasNonTrivialDestructor())

1
clang/lib/CodeGen/CGVTables.cpp
View File

@ -194,6 +194,7 @@ void CodeGenFunction::StartThunk(llvm::Function *Fn, GlobalDecl GD,
const CGFunctionInfo &FnInfo) {
assert(!CurGD.getDecl() && "CurGD was already set!");
CurGD = GD;
CurFuncIsThunk = true;
// Build FunctionArgs.
const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());

20
clang/lib/CodeGen/CodeGenFunction.cpp
View File

@ -38,16 +38,16 @@ CodeGenFunction::CodeGenFunction(CodeGenModule &cgm, bool suppressNewContext)
Builder(cgm.getModule().getContext(), llvm::ConstantFolder(),
CGBuilderInserterTy(this)),
CapturedStmtInfo(nullptr), SanOpts(&CGM.getLangOpts().Sanitize),
IsSanitizerScope(false), AutoreleaseResult(false), BlockInfo(nullptr),
BlockPointer(nullptr), LambdaThisCaptureField(nullptr),
NormalCleanupDest(nullptr), NextCleanupDestIndex(1),
FirstBlockInfo(nullptr), EHResumeBlock(nullptr), ExceptionSlot(nullptr),
EHSelectorSlot(nullptr), DebugInfo(CGM.getModuleDebugInfo()),
DisableDebugInfo(false), DidCallStackSave(false), IndirectBranch(nullptr),
PGO(cgm), SwitchInsn(nullptr), SwitchWeights(nullptr),
CaseRangeBlock(nullptr), UnreachableBlock(nullptr), NumReturnExprs(0),
NumSimpleReturnExprs(0), CXXABIThisDecl(nullptr),
CXXABIThisValue(nullptr), CXXThisValue(nullptr),
IsSanitizerScope(false), CurFuncIsThunk(false), AutoreleaseResult(false),
BlockInfo(nullptr), BlockPointer(nullptr),
LambdaThisCaptureField(nullptr), NormalCleanupDest(nullptr),
NextCleanupDestIndex(1), FirstBlockInfo(nullptr), EHResumeBlock(nullptr),
ExceptionSlot(nullptr), EHSelectorSlot(nullptr),
DebugInfo(CGM.getModuleDebugInfo()), DisableDebugInfo(false),
DidCallStackSave(false), IndirectBranch(nullptr), PGO(cgm),
SwitchInsn(nullptr), SwitchWeights(nullptr), CaseRangeBlock(nullptr),
UnreachableBlock(nullptr), NumReturnExprs(0), NumSimpleReturnExprs(0),
CXXABIThisDecl(nullptr), CXXABIThisValue(nullptr), CXXThisValue(nullptr),
CXXDefaultInitExprThis(nullptr), CXXStructorImplicitParamDecl(nullptr),
CXXStructorImplicitParamValue(nullptr), OutermostConditional(nullptr),
CurLexicalScope(nullptr), TerminateLandingPad(nullptr),

4
clang/lib/CodeGen/CodeGenFunction.h
View File

@ -258,6 +258,10 @@ public:
~SanitizerScope();
};
/// In C++, whether we are code generating a thunk. This controls whether we
/// should emit cleanups.
bool CurFuncIsThunk;
/// In ARC, whether we should autorelease the return value.
bool AutoreleaseResult;

25
clang/test/CodeGenCXX/microsoft-abi-byval-thunks.cpp Normal file
View File

@ -0,0 +1,25 @@
// RUN: not %clang_cc1 %s -fno-rtti -triple=i686-pc-win32 -emit-llvm -o /dev/null 2>&1 | FileCheck --check-prefix=CHECK32
// RUN: %clang_cc1 %s -fno-rtti -triple=x86_64-pc-win32 -emit-llvm -o - | FileCheck --check-prefix=CHECK64
namespace byval_thunk {
struct Agg {
Agg();
Agg(const Agg &);
~Agg();
int x;
};
struct A { virtual void foo(Agg x); };
struct B { virtual void foo(Agg x); };
struct C : A, B { virtual void foo(Agg x); };
C c;
// CHECK32: cannot compile this non-trivial argument copy for thunk yet
// CHECK64-LABEL: define linkonce_odr void @"\01?foo@C@byval_thunk@@W7EAAXUAgg@2@@Z"
// CHECK64: (%"struct.byval_thunk::C"* %this, %"struct.byval_thunk::Agg"* %x)
// CHECK64: getelementptr i8* %{{.*}}, i32 -8
// CHECK64: call void @"\01?foo@C@byval_thunk@@UEAAXUAgg@2@@Z"(%"struct.byval_thunk::C"* %2, %"struct.byval_thunk::Agg"* %x)
// CHECK64-NOT: call
// CHECK64: ret void
}