stack_checks.h revision 83b1940e6482b9d8feba5c492507735686650ea5 
1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef ART_COMPILER_UTILS_STACK_CHECKS_H_
18#define ART_COMPILER_UTILS_STACK_CHECKS_H_
19
20#include "instruction_set.h"
21
22namespace art {
23
24// Size of a frame that we definitely consider large. Anything larger than this should
25// definitely get a stack overflow check.
26static constexpr size_t kLargeFrameSize = 2 * KB;
27
28// Size of a frame that should be small. Anything leaf method smaller than this should run
29// without a stack overflow check.
30// The constant is from experience with frameworks code.
31static constexpr size_t kSmallFrameSize = 1 * KB;
32
33// Determine whether a frame is small or large, used in the decision on whether to elide a
34// stack overflow check on method entry.
35//
36// A frame is considered large when it's either above kLargeFrameSize, or a quarter of the
37// overflow-usable stack space.
38static inline bool IsLargeFrame(size_t size, InstructionSet isa) {
39  return size >= kLargeFrameSize || size >= GetStackOverflowReservedBytes(isa) / 4;
40}
41
42}  // namespace art
43
44#endif  // ART_COMPILER_UTILS_STACK_CHECKS_H_
45