Merge remote-tracking branch 'origin/swift-4.0-branch' into stable
diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index 00c9785..205b65e 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -532,6 +532,15 @@
SanOpts.has(SanitizerKind::Vptr);
}
+/// Check if a runtime null check for \p Ptr can be omitted.
+static bool canOmitPointerNullCheck(llvm::Value *Ptr) {
+ // Note: do not perform any constant-folding in this function. That is best
+ // left to the IR builder.
+
+ // Pointers to alloca'd memory are non-null.
+ return isa<llvm::AllocaInst>(Ptr->stripPointerCastsNoFollowAliases());
+}
+
void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc,
llvm::Value *Ptr, QualType Ty,
CharUnits Alignment,
@@ -553,19 +562,28 @@
bool AllowNullPointers = TCK == TCK_DowncastPointer || TCK == TCK_Upcast ||
TCK == TCK_UpcastToVirtualBase;
if ((SanOpts.has(SanitizerKind::Null) || AllowNullPointers) &&
- !SkippedChecks.has(SanitizerKind::Null)) {
+ !SkippedChecks.has(SanitizerKind::Null) &&
+ !canOmitPointerNullCheck(Ptr)) {
// The glvalue must not be an empty glvalue.
llvm::Value *IsNonNull = Builder.CreateIsNotNull(Ptr);
- if (AllowNullPointers) {
- // When performing pointer casts, it's OK if the value is null.
- // Skip the remaining checks in that case.
- Done = createBasicBlock("null");
- llvm::BasicBlock *Rest = createBasicBlock("not.null");
- Builder.CreateCondBr(IsNonNull, Rest, Done);
- EmitBlock(Rest);
- } else {
- Checks.push_back(std::make_pair(IsNonNull, SanitizerKind::Null));
+ // The IR builder can constant-fold the null check if the pointer points to
+ // a constant.
+ bool PtrIsNonNull =
+ IsNonNull == llvm::ConstantInt::getTrue(getLLVMContext());
+
+ // Skip the null check if the pointer is known to be non-null.
+ if (!PtrIsNonNull) {
+ if (AllowNullPointers) {
+ // When performing pointer casts, it's OK if the value is null.
+ // Skip the remaining checks in that case.
+ Done = createBasicBlock("null");
+ llvm::BasicBlock *Rest = createBasicBlock("not.null");
+ Builder.CreateCondBr(IsNonNull, Rest, Done);
+ EmitBlock(Rest);
+ } else {
+ Checks.push_back(std::make_pair(IsNonNull, SanitizerKind::Null));
+ }
}
}
diff --git a/test/CodeGenCXX/ubsan-suppress-checks.cpp b/test/CodeGenCXX/ubsan-suppress-checks.cpp
index 8ec9455..d0e7b32 100644
--- a/test/CodeGenCXX/ubsan-suppress-checks.cpp
+++ b/test/CodeGenCXX/ubsan-suppress-checks.cpp
@@ -2,6 +2,20 @@
// 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
+// CHECK-LABEL: define void @_Z22load_non_null_pointersv
+void load_non_null_pointers() {
+ int var;
+ var = *&var;
+
+ int arr[1];
+ arr[0] = arr[0];
+
+ char c = "foo"[0];
+
+ // CHECK-NOT: icmp ne {{.*}}, null, !nosanitize
+ // CHECK: ret void
+}
+
struct A {
int foo;
@@ -29,8 +43,7 @@
};
f();
- // LAMBDA: icmp ne %class.anon* %[[FUNCVAR:.*]], null, !nosanitize
- // LAMBDA: %[[LAMBDAINT:[0-9]+]] = ptrtoint %class.anon* %[[FUNCVAR]] to i64, !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
@@ -127,8 +140,8 @@
struct B {
operator A*() const { return nullptr; }
- // CHECK-LABEL: define linkonce_odr i32 @_ZN1B11load_memberEv
- static int load_member() {
+ // CHECK-LABEL: define linkonce_odr i32 @_ZN1B11load_memberEPS_
+ static int load_member(B *bp) {
// Check &b before converting it to an A*.
// CHECK: call void @__ubsan_handle_type_mismatch
//
@@ -136,8 +149,7 @@
// NULL: call void @__ubsan_handle_type_mismatch
//
// CHECK-NOT: call void @__ubsan_handle_type_mismatch
- B b;
- return static_cast<A *>(b)->load_member();
+ return static_cast<A *>(*bp)->load_member();
// CHECK: ret i32
}
};
@@ -210,7 +222,7 @@
A::call_through_reference(*a);
A::call_through_pointer(a);
- B::load_member();
+ B::load_member(nullptr);
Base *b = new Derived;
b->load_member_1();
@@ -218,4 +230,6 @@
Derived *d;
d->load_member_2();
d->load_member_3();
+
+ load_non_null_pointers();
}
