sepavloff created this revision.
sepavloff added reviewers: rsmith, rjmccall, ikudrin.
With this change compiler generates alignment checks for wider range
of types. Previously such checks were generated only for the record types
with non-trivial default constructor. So the types like:
struct alignas(32) S2 { int x; };
typedef __attribute__((ext_vector_type(2), aligned(32))) float float32x2_t;
did not get checks when allocated by 'new' expression.
This change also optimizes the checks generated for the arrays created
in 'new' expressions. Previously the check was generated for each
invocation of type constructor. Now the check is generated only once
for entire array.
Repository:
rC Clang
https://reviews.llvm.org/D49589
Files:
lib/CodeGen/CGClass.cpp
lib/CodeGen/CGExprCXX.cpp
lib/CodeGen/CodeGenFunction.h
test/CodeGenCXX/ubsan-new-checks.cpp
Index: test/CodeGenCXX/ubsan-new-checks.cpp
===================================================================
--- /dev/null
+++ test/CodeGenCXX/ubsan-new-checks.cpp
@@ -0,0 +1,54 @@
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -std=c++11 -S -emit-llvm -fsanitize=alignment %s -o - | FileCheck %s
+
+struct alignas(32) S1 {
+ int x;
+ S1();
+};
+
+struct alignas(32) S2 {
+ int x;
+};
+
+typedef __attribute__((ext_vector_type(2), aligned(32))) float float32x2_t;
+
+S1 *func_01() {
+ // CHECK-LABEL: define {{.*}} @_Z7func_01v
+ // CHECK: and i64 %{{.*}}, 31, !nosanitize
+ // CHECK: icmp eq i64 %{{.*}}, 0, !nosanitize
+ // CHECK: call void @_ZN2S1C1Ev(
+ // CHECK-NOT: and i64 %{{.*}}, 31, !nosanitize
+ // CHECK-NOT: icmp eq i64 %{{.*}}, 0, !nosanitize
+ return new S1[20];
+}
+
+S2 *func_02() {
+ // CHECK-LABEL: define {{.*}} @_Z7func_02v
+ // CHECK: and i64 %{{.*}}, 31, !nosanitize
+ // CHECK: icmp eq i64 %{{.*}}, 0, !nosanitize
+ return new S2;
+}
+
+S2 *func_03() {
+ // CHECK-LABEL: define {{.*}} @_Z7func_03v
+ // CHECK: and i64 %{{.*}}, 31, !nosanitize
+ // CHECK: icmp eq i64 %{{.*}}, 0, !nosanitize
+ // CHECK-NOT: and i64 %{{.*}}, 31, !nosanitize
+ // CHECK-NOT: icmp eq i64 %{{.*}}, 0, !nosanitize
+ return new S2[20];
+}
+
+float32x2_t *func_04() {
+ // CHECK-LABEL: define {{.*}} @_Z7func_04v
+ // CHECK: and i64 %{{.*}}, 31, !nosanitize
+ // CHECK: icmp eq i64 %{{.*}}, 0, !nosanitize
+ return new float32x2_t;
+}
+
+float32x2_t *func_05() {
+ // CHECK-LABEL: define {{.*}} @_Z7func_05v
+ // CHECK: and i64 %{{.*}}, 31, !nosanitize
+ // CHECK: icmp eq i64 %{{.*}}, 0, !nosanitize
+ // CHECK-NOT: and i64 %{{.*}}, 31, !nosanitize
+ // CHECK-NOT: icmp eq i64 %{{.*}}, 0, !nosanitize
+ return new float32x2_t[20];
+}
Index: lib/CodeGen/CodeGenFunction.h
===================================================================
--- lib/CodeGen/CodeGenFunction.h
+++ lib/CodeGen/CodeGenFunction.h
@@ -376,6 +376,25 @@
~SanitizerScope();
};
+ /// True if sanitizer checks for current pointer value are generated.
+ bool PointerChecksAreEmitted = false;
+
+ /// RAII object to track generation of sanitizer pointer checks.
+ class PointerChecksRAII {
+ CodeGenFunction *CGF;
+ bool PrevValue;
+ public:
+ PointerChecksRAII(CodeGenFunction *CGF)
+ : CGF(CGF), PrevValue(CGF->PointerChecksAreEmitted) {
+ CGF->PointerChecksAreEmitted = true;
+ }
+ ~PointerChecksRAII() {
+ if (!PrevValue)
+ CGF->PointerChecksAreEmitted = false;
+ }
+ bool shouldEmitChecks() const { return !PrevValue; }
+ };
+
/// In C++, whether we are code generating a thunk. This controls whether we
/// should emit cleanups.
bool CurFuncIsThunk = false;
Index: lib/CodeGen/CGExprCXX.cpp
===================================================================
--- lib/CodeGen/CGExprCXX.cpp
+++ lib/CodeGen/CGExprCXX.cpp
@@ -1271,6 +1271,15 @@
Address NewPtr, llvm::Value *NumElements,
llvm::Value *AllocSizeWithoutCookie) {
ApplyDebugLocation DL(CGF, E);
+
+ // Emit sanitizer checks for pointer value now, so that in the case of an
+ // array it was checked only once and not at each constructor call.
+ CodeGenFunction::PointerChecksRAII PC(&CGF);
+ if (PC.shouldEmitChecks())
+ CGF.EmitTypeCheck(CodeGenFunction::TCK_ConstructorCall,
+ E->getAllocatedTypeSourceInfo()->getTypeLoc().getBeginLoc(),
+ NewPtr.getPointer(), ElementType);
+
if (E->isArray())
CGF.EmitNewArrayInitializer(E, ElementType, ElementTy, NewPtr, NumElements,
AllocSizeWithoutCookie);
Index: lib/CodeGen/CGClass.cpp
===================================================================
--- lib/CodeGen/CGClass.cpp
+++ lib/CodeGen/CGClass.cpp
@@ -2068,11 +2068,10 @@
SourceLocation Loc) {
const CXXRecordDecl *ClassDecl = D->getParent();
- // C++11 [class.mfct.non-static]p2:
- // If a non-static member function of a class X is called for an object that
- // is not of type X, or of a type derived from X, the behavior is undefined.
- EmitTypeCheck(CodeGenFunction::TCK_ConstructorCall, Loc,
- This.getPointer(), getContext().getRecordType(ClassDecl));
+ PointerChecksRAII PC(this);
+ if (PC.shouldEmitChecks())
+ EmitTypeCheck(CodeGenFunction::TCK_ConstructorCall, Loc,
+ This.getPointer(), getContext().getRecordType(ClassDecl));
if (D->isTrivial() && D->isDefaultConstructor()) {
assert(Args.size() == 1 && "trivial default ctor with args");
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