courbet updated this revision to Diff 332931.
courbet added a comment.
Forgot to add test file.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D99248/new/
https://reviews.llvm.org/D99248
Files:
clang/lib/CodeGen/CGExpr.cpp
clang/test/CodeGen/array-bounds.cpp
Index: clang/test/CodeGen/array-bounds.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGen/array-bounds.cpp
@@ -0,0 +1,56 @@
+// RUN: %clang_cc1 -triple x86_64-linux -O1 -disable-llvm-passes %s \
+// RUN: -emit-llvm -o - | FileCheck %s
+//
+// Check that we generate array bound information for accesses to array
+// elements.
+
+struct A { int i; };
+struct B { A a[1]; };
+struct C { int i; int x[3]; };
+struct D { int i; int* x; };
+struct E { int x[3][5]; };
+
+//TODO: std::array
+
+int deref(C *c, int j) {
+// CHECK-LABEL: _Z5derefP1Ci
+// CHECK: [[INDEX:%.*]] = call i64 @llvm.annotation{{.*}}, !range [[RANGE_0_3:!.*]]
+// CHECK: getelementptr {{.*}} [[INDEX]]
+ return c->x[j];
+}
+
+int deref_noindex(B *b) {
+// CHECK-LABEL: _Z13deref_noindexP1B
+// CHECK-NOT: llvm.annotation
+// CHECK: getelementptr {{.*}}
+ return b->a->i;
+}
+
+int deref_ptr(D *d, int j) {
+// CHECK-LABEL: _Z9deref_ptrP1Di
+// CHECK-NOT: llvm.annotation
+// CHECK: getelementptr {{.*}}
+ return d->x[j];
+}
+
+int deref_multi(E *e, int j, int k) {
+// CHECK-LABEL: _Z11deref_multiP1Eii
+// CHECK: [[INDEX1:%.*]] = call i64 @llvm.annotation{{.*}}, !range [[RANGE_0_3]]
+// CHECK: getelementptr {{.*}} [[INDEX1]]
+// CHECK: [[INDEX2:%.*]] = call i64 @llvm.annotation{{.*}}, !range [[RANGE_0_5:!.*]]
+// CHECK: getelementptr {{.*}} [[INDEX2]]
+ return e->x[j][k];
+}
+
+// We are not dereferencing the computed address, it is valid to compute a
+// past-the-end address.
+int* addr(C *c, int j) {
+// CHECK-LABEL: _Z4addrP1Ci
+// CHECK: [[INDEX:%.*]] = call i64 @llvm.annotation{{.*}}, !range [[RANGE_0_4:!.*]]
+// CHECK: getelementptr {{.*}} [[INDEX]]
+ return &c->x[j];
+}
+
+// CHECK-DAG: [[RANGE_0_3]] = !{i64 0, i64 3}
+// CHECK-DAG: [[RANGE_0_4]] = !{i64 0, i64 4}
+// CHECK-DAG: [[RANGE_0_5]] = !{i64 0, i64 5}
Index: clang/lib/CodeGen/CGExpr.cpp
===================================================================
--- clang/lib/CodeGen/CGExpr.cpp
+++ clang/lib/CodeGen/CGExpr.cpp
@@ -1249,7 +1249,7 @@
LValue CodeGenFunction::EmitCheckedLValue(const Expr *E, TypeCheckKind TCK) {
LValue LV;
- if (SanOpts.has(SanitizerKind::ArrayBounds) && isa<ArraySubscriptExpr>(E))
+ if (isa<ArraySubscriptExpr>(E))
LV = EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E), /*Accessed*/true);
else
LV = EmitLValue(E);
@@ -3691,6 +3691,32 @@
return Address(eltPtr, eltAlign);
}
+// Add range metadata: It is UB to subscript outside of the array, therefore
+// array indices are known to be in range:
+// * [0, indexing_bound) if the array is accessed.
+// * [0, indexing_bound] if only address computation is preformed.
+static llvm::Value *addArrayIndexingRangeMetadata(CodeGenFunction &CGF,
+ const Expr *Base,
+ llvm::Value *Idx,
+ bool Accessed) {
+ QualType IdxTy;
+ llvm::ConstantInt *Bound = dyn_cast_or_null<llvm::ConstantInt>(
+ getArrayIndexingBound(CGF, Base, IdxTy));
+ if (Bound == nullptr)
+ return Idx;
+ llvm::Instruction *AnnotatedIdx =
+ CGF.Builder.CreateIntrinsic(llvm::Intrinsic::annotation, {Idx->getType()},
+ {Idx, llvm::UndefValue::get(CGF.Int8PtrTy),
+ llvm::UndefValue::get(CGF.Int8PtrTy),
+ llvm::UndefValue::get(CGF.Int32Ty)});
+ llvm::MDBuilder MDHelper(CGF.getLLVMContext());
+ AnnotatedIdx->setMetadata(
+ llvm::LLVMContext::MD_range,
+ MDHelper.createRange(llvm::APInt(Bound->getBitWidth(), 0),
+ Bound->getValue() + (Accessed ? 0 : 1)));
+ return AnnotatedIdx;
+}
+
LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E,
bool Accessed) {
// The index must always be an integer, which is not an aggregate. Emit it
@@ -3716,6 +3742,9 @@
if (Promote && Idx->getType() != IntPtrTy)
Idx = Builder.CreateIntCast(Idx, IntPtrTy, IdxSigned, "idxprom");
+ if (CGM.getCodeGenOpts().OptimizationLevel > 0)
+ Idx = addArrayIndexingRangeMetadata(*this, E->getBase(), Idx, Accessed);
+
return Idx;
};
IdxPre = nullptr;
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