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[ubsan] Reduce alignment checking of C++ object pointers 

This patch teaches ubsan to insert an alignment check for the 'this'
pointer at the start of each method/lambda. This allows clang to emit
significantly fewer alignment checks overall, because if 'this' is
aligned, so are its fields.

This is essentially the same thing r295515 does, but for the alignment
check instead of the null check. One difference is that we keep the
alignment checks on member expressions where the base is a DeclRefExpr.
There's an opportunity to diagnose unaligned accesses in this situation
(as pointed out by Eli, see PR32630).

Testing: check-clang, check-ubsan, and a stage2 ubsan build.

Along with the patch from D30285, this roughly halves the amount of
alignment checks we emit when compiling X86FastISel.cpp. Here are the
numbers from patched/unpatched clangs based on r298160.

  ------------------------------------------
  | Setup          | # of alignment checks |
  ------------------------------------------
  | unpatched, -O0 |                 24326 |
  | patched, -O0   |                 12717 | (-47.7%)
  ------------------------------------------

Differential Revision: https://reviews.llvm.org/D30283

llvm-svn: 300370
This commit is contained in:
Vedant Kumar 2017-04-14 22:03:34 +00:00
parent 9edaea21af
commit ffd7c887d6
8 changed files with 277 additions and 206 deletions
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18
clang/lib/CodeGen/CGExpr.cpp
View File

@ -954,10 +954,7 @@ LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
E->getType());
}
bool CodeGenFunction::IsDeclRefOrWrappedCXXThis(const Expr *Obj) {
if (isa<DeclRefExpr>(Obj))
return true;
bool CodeGenFunction::IsWrappedCXXThis(const Expr *Obj) {
const Expr *Base = Obj;
while (!isa<CXXThisExpr>(Base)) {
// The result of a dynamic_cast can be null.
@ -988,9 +985,13 @@ LValue CodeGenFunction::EmitCheckedLValue(const Expr *E, TypeCheckKind TCK) {
LV = EmitLValue(E);
if (!isa<DeclRefExpr>(E) && !LV.isBitField() && LV.isSimple()) {
SanitizerSet SkippedChecks;
if (const auto *ME = dyn_cast<MemberExpr>(E))
if (IsDeclRefOrWrappedCXXThis(ME->getBase()))
if (const auto *ME = dyn_cast<MemberExpr>(E)) {
bool IsBaseCXXThis = IsWrappedCXXThis(ME->getBase());
if (IsBaseCXXThis)
SkippedChecks.set(SanitizerKind::Alignment, true);
if (IsBaseCXXThis || isa<DeclRefExpr>(ME->getBase()))
SkippedChecks.set(SanitizerKind::Null, true);
}
EmitTypeCheck(TCK, E->getExprLoc(), LV.getPointer(),
E->getType(), LV.getAlignment(), SkippedChecks);
}
@ -3429,7 +3430,10 @@ LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
Address Addr = EmitPointerWithAlignment(BaseExpr, &AlignSource);
QualType PtrTy = BaseExpr->getType()->getPointeeType();
SanitizerSet SkippedChecks;
if (IsDeclRefOrWrappedCXXThis(BaseExpr))
bool IsBaseCXXThis = IsWrappedCXXThis(BaseExpr);
if (IsBaseCXXThis)
SkippedChecks.set(SanitizerKind::Alignment, true);
if (IsBaseCXXThis || isa<DeclRefExpr>(BaseExpr))
SkippedChecks.set(SanitizerKind::Null, true);
EmitTypeCheck(TCK_MemberAccess, E->getExprLoc(), Addr.getPointer(), PtrTy,
/*Alignment=*/CharUnits::Zero(), SkippedChecks);

9
clang/lib/CodeGen/CGExprCXX.cpp
View File

@ -301,9 +301,14 @@ RValue CodeGenFunction::EmitCXXMemberOrOperatorMemberCallExpr(
CallLoc = CE->getExprLoc();
SanitizerSet SkippedChecks;
if (const auto *CMCE = dyn_cast<CXXMemberCallExpr>(CE))
if (IsDeclRefOrWrappedCXXThis(CMCE->getImplicitObjectArgument()))
if (const auto *CMCE = dyn_cast<CXXMemberCallExpr>(CE)) {
auto *IOA = CMCE->getImplicitObjectArgument();
bool IsImplicitObjectCXXThis = IsWrappedCXXThis(IOA);
if (IsImplicitObjectCXXThis)
SkippedChecks.set(SanitizerKind::Alignment, true);
if (IsImplicitObjectCXXThis || isa<DeclRefExpr>(IOA))
SkippedChecks.set(SanitizerKind::Null, true);
}
EmitTypeCheck(
isa<CXXConstructorDecl>(CalleeDecl) ? CodeGenFunction::TCK_ConstructorCall
: CodeGenFunction::TCK_MemberCall,

9
clang/lib/CodeGen/CodeGenFunction.cpp
View File

@ -963,13 +963,14 @@ void CodeGenFunction::StartFunction(GlobalDecl GD,
CXXThisValue = CXXABIThisValue;
}
// Null-check the 'this' pointer once per function, if it's available.
// Check the 'this' pointer once per function, if it's available.
if (CXXThisValue) {
SanitizerSet SkippedChecks;
SkippedChecks.set(SanitizerKind::Alignment, true);
SkippedChecks.set(SanitizerKind::ObjectSize, true);
EmitTypeCheck(TCK_Load, Loc, CXXThisValue, MD->getThisType(getContext()),
/*Alignment=*/CharUnits::Zero(), SkippedChecks);
QualType ThisTy = MD->getThisType(getContext());
EmitTypeCheck(TCK_Load, Loc, CXXThisValue, ThisTy,
getContext().getTypeAlignInChars(ThisTy->getPointeeType()),
SkippedChecks);
}
}

5
clang/lib/CodeGen/CodeGenFunction.h
View File

@ -2077,9 +2077,8 @@ public:
llvm::BlockAddress *GetAddrOfLabel(const LabelDecl *L);
llvm::BasicBlock *GetIndirectGotoBlock();
/// Check if \p E is a reference, or a C++ "this" pointer wrapped in value-
/// preserving casts.
static bool IsDeclRefOrWrappedCXXThis(const Expr *E);
/// Check if \p E is a C++ "this" pointer wrapped in value-preserving casts.
static bool IsWrappedCXXThis(const Expr *E);
/// EmitNullInitialization - Generate code to set a value of the given type to
/// null, If the type contains data member pointers, they will be initialized

29
clang/test/CodeGenCXX/ubsan-global-alignment.cpp Normal file
View File

@ -0,0 +1,29 @@
// RUN: %clang_cc1 -std=c++11 -triple x86_64-apple-darwin10 -emit-llvm -o - %s -fsanitize=alignment | FileCheck %s
struct S {
int I;
};
extern S g_S;
extern S array_S[];
// CHECK-LABEL: define i32 @_Z18load_extern_global
int load_extern_global() {
// FIXME: The IR builder constant-folds the alignment check away to 'true'
// here, so we never call the diagnostic. This is PR32630.
// CHECK-NOT: ptrtoint i32* {{.*}} to i32, !nosanitize
// CHECK: [[I:%.*]] = load i32, i32* getelementptr inbounds (%struct.S, %struct.S* @g_S, i32 0, i32 0), align 4
// CHECK-NEXT: ret i32 [[I]]
return g_S.I;
}
// CHECK-LABEL: define i32 @_Z22load_from_extern_array
int load_from_extern_array(int I) {
// CHECK: [[I:%.*]] = getelementptr inbounds %struct.S, %struct.S* {{.*}}, i32 0, i32 0
// CHECK-NEXT: [[PTRTOINT:%.*]] = ptrtoint i32* [[I]] to i64, !nosanitize
// CHECK-NEXT: [[AND:%.*]] = and i64 [[PTRTOINT]], 3, !nosanitize
// CHECK-NEXT: [[ICMP:%.*]] = icmp eq i64 [[AND]], 0, !nosanitize
// CHECK-NEXT: br i1 [[ICMP]]
// CHECK: call void @__ubsan_handle_type_mismatch
return array_S[I].I;
}

221
clang/test/CodeGenCXX/ubsan-suppress-checks.cpp Normal file
View File

@ -0,0 +1,221 @@
// RUN: %clang_cc1 -std=c++11 -triple x86_64-apple-darwin10 -emit-llvm -o - %s -fsanitize=alignment | FileCheck %s --check-prefixes=CHECK,ALIGN
// RUN: %clang_cc1 -std=c++11 -triple x86_64-apple-darwin10 -emit-llvm -o - %s -fsanitize=null | FileCheck %s --check-prefixes=CHECK,NULL
// RUN: %clang_cc1 -std=c++11 -triple x86_64-apple-darwin10 -emit-llvm -o - %s -fsanitize=alignment,null -DCHECK_LAMBDA | FileCheck %s --check-prefixes=LAMBDA
struct A {
int foo;
// CHECK-LABEL: define linkonce_odr void @_ZN1A10do_nothingEv
void do_nothing() {
// ALIGN: %[[THISINT1:[0-9]+]] = ptrtoint %struct.A* %{{.*}} to i64, !nosanitize
// ALIGN: and i64 %[[THISINT1]], 3, !nosanitize
// NULL: icmp ne %struct.A* %[[THIS1:[a-z0-9]+]], null, !nosanitize
// NULL: ptrtoint %struct.A* %[[THIS1]] to i64, !nosanitize
// CHECK: call void @__ubsan_handle_type_mismatch
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
// CHECK: ret void
}
#ifdef CHECK_LAMBDA
// LAMBDA-LABEL: define linkonce_odr void @_ZN1A22do_nothing_with_lambdaEv
void do_nothing_with_lambda() {
// LAMBDA: icmp ne %struct.A* %[[THIS2:[a-z0-9]+]], null, !nosanitize
// LAMBDA: %[[THISINT2:[0-9]+]] = ptrtoint %struct.A* %[[THIS2]] to i64, !nosanitize
// LAMBDA: and i64 %[[THISINT2]], 3, !nosanitize
// LAMBDA: call void @__ubsan_handle_type_mismatch
auto f = [&] {
foo = 0;
};
f();
// LAMBDA: icmp ne %class.anon* %[[FUNCVAR:.*]], null, !nosanitize
// LAMBDA: %[[LAMBDAINT:[0-9]+]] = ptrtoint %class.anon* %[[FUNCVAR]] to i64, !nosanitize
// LAMBDA: and i64 %[[LAMBDAINT]], 7, !nosanitize
// LAMBDA: call void @__ubsan_handle_type_mismatch
// LAMBDA-NOT: call void @__ubsan_handle_type_mismatch
// LAMBDA: ret void
}
// Check the IR for the lambda:
//
// LAMBDA-LABEL: define linkonce_odr void @_ZZN1A22do_nothing_with_lambdaEvENKUlvE_clEv
// LAMBDA: call void @__ubsan_handle_type_mismatch
// LAMBDA-NOT: call void @__ubsan_handle_type_mismatch
// LAMBDA: ret void
#endif
// CHECK-LABEL: define linkonce_odr i32 @_ZN1A11load_memberEv
int load_member() {
// ALIGN: %[[THISINT3:[0-9]+]] = ptrtoint %struct.A* %{{.*}} to i64, !nosanitize
// ALIGN: and i64 %[[THISINT3]], 3, !nosanitize
// NULL: icmp ne %struct.A* %[[THIS3:[a-z0-9]+]], null, !nosanitize
// NULL: ptrtoint %struct.A* %[[THIS3]] to i64, !nosanitize
// CHECK: call void @__ubsan_handle_type_mismatch
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
return foo;
// CHECK: ret i32
}
// CHECK-LABEL: define linkonce_odr i32 @_ZN1A11call_methodEv
int call_method() {
// ALIGN: %[[THISINT4:[0-9]+]] = ptrtoint %struct.A* %{{.*}} to i64, !nosanitize
// ALIGN: and i64 %[[THISINT4]], 3, !nosanitize
// NULL: icmp ne %struct.A* %[[THIS4:[a-z0-9]+]], null, !nosanitize
// NULL: ptrtoint %struct.A* %[[THIS4]] to i64, !nosanitize
// CHECK: call void @__ubsan_handle_type_mismatch
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
return load_member();
// CHECK: ret i32
}
// CHECK-LABEL: define linkonce_odr void @_ZN1A15assign_member_1Ev
void assign_member_1() {
// ALIGN: %[[THISINT5:[0-9]+]] = ptrtoint %struct.A* %{{.*}} to i64, !nosanitize
// ALIGN: and i64 %[[THISINT5]], 3, !nosanitize
// NULL: icmp ne %struct.A* %[[THIS5:[a-z0-9]+]], null, !nosanitize
// NULL: ptrtoint %struct.A* %[[THIS5]] to i64, !nosanitize
// CHECK: call void @__ubsan_handle_type_mismatch
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
foo = 0;
// CHECK: ret void
}
// CHECK-LABEL: define linkonce_odr void @_ZN1A15assign_member_2Ev
void assign_member_2() {
// ALIGN: %[[THISINT6:[0-9]+]] = ptrtoint %struct.A* %{{.*}} to i64, !nosanitize
// ALIGN: and i64 %[[THISINT6]], 3, !nosanitize
// NULL: icmp ne %struct.A* %[[THIS6:[a-z0-9]+]], null, !nosanitize
// NULL: ptrtoint %struct.A* %[[THIS6]] to i64, !nosanitize
// CHECK: call void @__ubsan_handle_type_mismatch
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
(__extension__ (this))->foo = 0;
// CHECK: ret void
}
// CHECK-LABEL: define linkonce_odr void @_ZNK1A15assign_member_3Ev
void assign_member_3() const {
// ALIGN: %[[THISINT7:[0-9]+]] = ptrtoint %struct.A* %{{.*}} to i64, !nosanitize
// ALIGN: and i64 %[[THISINT7]], 3, !nosanitize
// NULL: icmp ne %struct.A* %[[THIS7:[a-z0-9]+]], null, !nosanitize
// NULL: ptrtoint %struct.A* %[[THIS7]] to i64, !nosanitize
// CHECK: call void @__ubsan_handle_type_mismatch
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
const_cast<A *>(this)->foo = 0;
// CHECK: ret void
}
// CHECK-LABEL: define linkonce_odr i32 @_ZN1A22call_through_referenceERS_
static int call_through_reference(A &a) {
// ALIGN: %[[OBJINT:[0-9]+]] = ptrtoint %struct.A* %{{.*}} to i64, !nosanitize
// ALIGN: and i64 %[[OBJINT]], 3, !nosanitize
// ALIGN: call void @__ubsan_handle_type_mismatch
// NULL-NOT: call void @__ubsan_handle_type_mismatch
return a.load_member();
// CHECK: ret i32
}
// CHECK-LABEL: define linkonce_odr i32 @_ZN1A20call_through_pointerEPS_
static int call_through_pointer(A *a) {
// CHECK: call void @__ubsan_handle_type_mismatch
return a->load_member();
// CHECK: ret i32
}
};
struct B {
operator A*() const { return nullptr; }
// CHECK-LABEL: define linkonce_odr i32 @_ZN1B11load_memberEv
static int load_member() {
// Check &b before converting it to an A*.
// CHECK: call void @__ubsan_handle_type_mismatch
//
// Check the result of the conversion before using it.
// CHECK: call void @__ubsan_handle_type_mismatch
//
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
B b;
return static_cast<A *>(b)->load_member();
// CHECK: ret i32
}
};
struct Base {
int foo;
virtual int load_member_1() = 0;
};
struct Derived : public Base {
int bar;
// CHECK-LABEL: define linkonce_odr i32 @_ZN7Derived13load_member_2Ev
int load_member_2() {
// ALIGN: %[[THISINT8:[0-9]+]] = ptrtoint %struct.Derived* %{{.*}} to i64, !nosanitize
// ALIGN: and i64 %[[THISINT8]], 7, !nosanitize
// ALIGN: call void @__ubsan_handle_type_mismatch
// NULL: icmp ne %struct.Derived* %[[THIS8:[a-z0-9]+]], null, !nosanitize
// NULL: ptrtoint %struct.Derived* %[[THIS8]] to i64, !nosanitize
// CHECK: call void @__ubsan_handle_type_mismatch
//
// Check the result of the cast before using it.
// CHECK: call void @__ubsan_handle_type_mismatch
//
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
return dynamic_cast<Base *>(this)->load_member_1();
// CHECK: ret i32
}
// CHECK-LABEL: define linkonce_odr i32 @_ZN7Derived13load_member_3Ev
int load_member_3() {
// ALIGN: %[[THISINT9:[0-9]+]] = ptrtoint %struct.Derived* %{{.*}} to i64, !nosanitize
// ALIGN: and i64 %[[THISINT9]], 7, !nosanitize
// ALIGN: call void @__ubsan_handle_type_mismatch
// ALIGN: call void @__ubsan_handle_type_mismatch
// NULL: icmp ne %struct.Derived* %[[THIS9:[a-z0-9]+]], null, !nosanitize
// NULL: ptrtoint %struct.Derived* %[[THIS9]] to i64, !nosanitize
// CHECK: call void @__ubsan_handle_type_mismatch
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
return reinterpret_cast<Derived *>(static_cast<Base *>(this))->foo;
// CHECK: ret i32
}
// CHECK-LABEL: define linkonce_odr i32 @_ZN7Derived13load_member_1Ev
int load_member_1() override {
// ALIGN: %[[THISINT10:[0-9]+]] = ptrtoint %struct.Derived* %{{.*}} to i64, !nosanitize
// ALIGN: and i64 %[[THISINT10]], 7, !nosanitize
// ALIGN: call void @__ubsan_handle_type_mismatch
// NULL: icmp ne %struct.Derived* %[[THIS10:[a-z0-9]+]], null, !nosanitize
// NULL: ptrtoint %struct.Derived* %[[THIS10]] to i64, !nosanitize
// CHECK: call void @__ubsan_handle_type_mismatch
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
return foo + bar;
// CHECK: ret i32
}
};
void force_irgen() {
A *a;
a->do_nothing();
#ifdef CHECK_LAMBDA
a->do_nothing_with_lambda();
#endif
a->load_member();
a->call_method();
a->assign_member_1();
a->assign_member_2();
a->assign_member_3();
A::call_through_reference(*a);
A::call_through_pointer(a);
B::load_member();
Base *b = new Derived;
b->load_member_1();
Derived *d;
d->load_member_2();
d->load_member_3();
}

188
clang/test/CodeGenCXX/ubsan-suppress-null-checks.cpp
View File

@ -1,188 +0,0 @@
// RUN: %clang_cc1 -std=c++11 -triple x86_64-apple-darwin10 -emit-llvm -o - %s -fsanitize=null | FileCheck %s
// RUN: %clang_cc1 -std=c++11 -triple x86_64-apple-darwin10 -emit-llvm -o - %s -fsanitize=null -DCHECK_LAMBDA | FileCheck %s --check-prefix=LAMBDA
struct A {
int foo;
// CHECK-LABEL: define linkonce_odr void @_ZN1A10do_nothingEv
void do_nothing() {
// CHECK: icmp ne %struct.A* %[[THIS1:[a-z0-9]+]], null, !nosanitize
// CHECK: ptrtoint %struct.A* %[[THIS1]] to i64, !nosanitize
// CHECK-NEXT: call void @__ubsan_handle_type_mismatch
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
// CHECK: ret void
}
#ifdef CHECK_LAMBDA
// LAMBDA-LABEL: define linkonce_odr void @_ZN1A22do_nothing_with_lambdaEv
void do_nothing_with_lambda() {
// LAMBDA: icmp ne %struct.A* %[[THIS2:[a-z0-9]+]], null, !nosanitize
// LAMBDA: ptrtoint %struct.A* %[[THIS2]] to i64, !nosanitize
// LAMBDA-NEXT: call void @__ubsan_handle_type_mismatch
auto f = [&] {
foo = 0;
};
f();
// LAMBDA: ret void
}
// Check the IR for the lambda:
//
// LAMBDA-LABEL: define linkonce_odr void @_ZZN1A22do_nothing_with_lambdaEvENKUlvE_clEv
// LAMBDA: call void @__ubsan_handle_type_mismatch
// LAMBDA-NOT: call void @__ubsan_handle_type_mismatch
// LAMBDA: ret void
#endif
// CHECK-LABEL: define linkonce_odr i32 @_ZN1A11load_memberEv
int load_member() {
// CHECK: icmp ne %struct.A* %[[THIS3:[a-z0-9]+]], null, !nosanitize
// CHECK: ptrtoint %struct.A* %[[THIS3]] to i64, !nosanitize
// CHECK-NEXT: call void @__ubsan_handle_type_mismatch
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
return foo;
// CHECK: ret i32
}
// CHECK-LABEL: define linkonce_odr i32 @_ZN1A11call_methodEv
int call_method() {
// CHECK: icmp ne %struct.A* %[[THIS4:[a-z0-9]+]], null, !nosanitize
// CHECK: ptrtoint %struct.A* %[[THIS4]] to i64, !nosanitize
// CHECK-NEXT: call void @__ubsan_handle_type_mismatch
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
return load_member();
// CHECK: ret i32
}
// CHECK-LABEL: define linkonce_odr void @_ZN1A15assign_member_1Ev
void assign_member_1() {
// CHECK: icmp ne %struct.A* %[[THIS5:[a-z0-9]+]], null, !nosanitize
// CHECK: ptrtoint %struct.A* %[[THIS5]] to i64, !nosanitize
// CHECK-NEXT: call void @__ubsan_handle_type_mismatch
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
foo = 0;
// CHECK: ret void
}
// CHECK-LABEL: define linkonce_odr void @_ZN1A15assign_member_2Ev
void assign_member_2() {
// CHECK: icmp ne %struct.A* %[[THIS6:[a-z0-9]+]], null, !nosanitize
// CHECK: ptrtoint %struct.A* %[[THIS6]] to i64, !nosanitize
// CHECK-NEXT: call void @__ubsan_handle_type_mismatch
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
(__extension__ (this))->foo = 0;
// CHECK: ret void
}
// CHECK-LABEL: define linkonce_odr void @_ZNK1A15assign_member_3Ev
void assign_member_3() const {
// CHECK: icmp ne %struct.A* %[[THIS7:[a-z0-9]+]], null, !nosanitize
// CHECK: ptrtoint %struct.A* %[[THIS7]] to i64, !nosanitize
// CHECK-NEXT: call void @__ubsan_handle_type_mismatch
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
const_cast<A *>(this)->foo = 0;
// CHECK: ret void
}
// CHECK-LABEL: define linkonce_odr i32 @_ZN1A22call_through_referenceERS_
static int call_through_reference(A &a) {
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
return a.load_member();
// CHECK: ret i32
}
// CHECK-LABEL: define linkonce_odr i32 @_ZN1A20call_through_pointerEPS_
static int call_through_pointer(A *a) {
// CHECK: call void @__ubsan_handle_type_mismatch
return a->load_member();
// CHECK: ret i32
}
};
struct B {
operator A*() const { return nullptr; }
// CHECK-LABEL: define linkonce_odr i32 @_ZN1B11load_memberEv
static int load_member() {
// Null-check &b before converting it to an A*.
// CHECK: call void @__ubsan_handle_type_mismatch
//
// Null-check the result of the conversion before using it.
// CHECK: call void @__ubsan_handle_type_mismatch
//
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
B b;
return static_cast<A *>(b)->load_member();
// CHECK: ret i32
}
};
struct Base {
int foo;
virtual int load_member_1() = 0;
};
struct Derived : public Base {
int bar;
// CHECK-LABEL: define linkonce_odr i32 @_ZN7Derived13load_member_2Ev
int load_member_2() {
// CHECK: icmp ne %struct.Derived* %[[THIS8:[a-z0-9]+]], null, !nosanitize
// CHECK: ptrtoint %struct.Derived* %[[THIS8]] to i64, !nosanitize
// CHECK-NEXT: call void @__ubsan_handle_type_mismatch
//
// Null-check the result of the cast before using it.
// CHECK: call void @__ubsan_handle_type_mismatch
//
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
return dynamic_cast<Base *>(this)->load_member_1();
// CHECK: ret i32
}
// CHECK-LABEL: define linkonce_odr i32 @_ZN7Derived13load_member_3Ev
int load_member_3() {
// CHECK: icmp ne %struct.Derived* %[[THIS9:[a-z0-9]+]], null, !nosanitize
// CHECK: ptrtoint %struct.Derived* %[[THIS9]] to i64, !nosanitize
// CHECK-NEXT: call void @__ubsan_handle_type_mismatch
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
return reinterpret_cast<Derived *>(static_cast<Base *>(this))->foo;
// CHECK: ret i32
}
// CHECK-LABEL: define linkonce_odr i32 @_ZN7Derived13load_member_1Ev
int load_member_1() override {
// CHECK: icmp ne %struct.Derived* %[[THIS10:[a-z0-9]+]], null, !nosanitize
// CHECK: ptrtoint %struct.Derived* %[[THIS10]] to i64, !nosanitize
// CHECK-NEXT: call void @__ubsan_handle_type_mismatch
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
return foo + bar;
// CHECK: ret i32
}
};
void force_irgen() {
A *a;
a->do_nothing();
#ifdef CHECK_LAMBDA
a->do_nothing_with_lambda();
#endif
a->load_member();
a->call_method();
a->assign_member_1();
a->assign_member_2();
a->assign_member_3();
A::call_through_reference(*a);
A::call_through_pointer(a);
B::load_member();
Base *b = new Derived;
b->load_member_1();
Derived *d;
d->load_member_2();
d->load_member_3();
}

4
clang/test/CodeGenCXX/ubsan-type-checks.cpp
View File

@ -5,8 +5,8 @@
struct A {
// COMMON-LABEL: define linkonce_odr void @_ZN1A10do_nothingEv
void do_nothing() {
// ALIGN-NOT: ptrtoint %struct.A* %{{.*}} to i64, !nosanitize
// ALIGN-NOT: and i64 %{{.*}}, 7, !nosanitize
// ALIGN: ptrtoint %struct.A* %{{.*}} to i64, !nosanitize
// ALIGN: and i64 %{{.*}}, 0, !nosanitize
// NULL: icmp ne %struct.A* %{{.*}}, null, !nosanitize