-fcatch-undefined-behavior: handler for VLA bound which evaluates to a non-positive value.

llvm-svn: 165582

compiler-rt/lib/ubsan/lit_tests/Misc/vla.c

@@ -0,0 +1,11 @@
+// RUN: %clang -fcatch-undefined-behavior %s -O3 -o %t
+// RUN: %t 2>&1 | FileCheck %s --check-prefix=CHECK-MINUS-ONE
+// RUN: %t a 2>&1 | FileCheck %s --check-prefix=CHECK-ZERO
+// RUN: %t a b
+
+int main(int argc, char **argv) {
+  // CHECK-MINUS-ONE: vla.c:9:11: fatal error: variable length array bound evaluates to non-positive value -1
+  // CHECK-ZERO: vla.c:9:11: fatal error: variable length array bound evaluates to non-positive value 0
+  int arr[argc - 2];
+  return 0;
+}

compiler-rt/lib/ubsan/ubsan_handlers.cc

@@ -126,3 +126,11 @@ void __ubsan::__ubsan_handle_missing_return(UnreachableData *Data) {
                   "without returning a value");
   Die();
 }
+
+void __ubsan::__ubsan_handle_vla_bound_not_positive(VLABoundData *Data,
+                                                    ValueHandle Bound) {
+  Diag(Data->Loc, "variable length array bound evaluates to "
+                  "non-positive value %0")
+    << Value(Data->Type, Bound);
+  Die();
+}

compiler-rt/lib/ubsan/ubsan_handlers.h

@@ -76,6 +76,15 @@ extern "C" void __ubsan_handle_builtin_unreachable(UnreachableData *Data);
 /// \brief Handle reaching the end of a value-returning function.
 extern "C" void __ubsan_handle_missing_return(UnreachableData *Data);
 
+struct VLABoundData {
+  SourceLocation Loc;
+  const TypeDescriptor &Type;
+};
+
+/// \brief Handle a VLA with a non-positive bound.
+extern "C" void __ubsan_handle_vla_bound_not_positive(VLABoundData *Data,
+                                                      ValueHandle Bound);
+
 }
 
 #endif // UBSAN_HANDLERS_H