runtime_primitives/include/berberis/runtime_primitives/config.h

/*
 * Copyright (C) 2023 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef BERBERIS_RUNTIME_PRIMITIVES_CONFIG_H_
#define BERBERIS_RUNTIME_PRIMITIVES_CONFIG_H_

#include <cstdint>

#include "berberis/runtime_primitives/platform.h"

namespace berberis::config {

// Size of the stack frame allocated in translated code prologue.
// As translated code ('slow') prologue executes much less frequently than
// region ('fast') prologue, it makes sense to allocate a frame there that
// suits most regions. Outstanding regions will expand it in their prologue.
// Assume the stack is properly aligned when entering translated code.
// TODO(b/232598137): If we discover that most regions don't need stack frame
// at all, then we might want to avoid extra altering of stack pointer in
// translated code prologue and keep stack misaligned. Then we'll need a
// kStackMisalignAtTranslatedCode config variable.
// TODO(b/232598137): 12 is what we get on x86-32 after stack alignment, update
// with, say, 90-percentile of (dynamic) frame size.
static constexpr uint32_t kFrameSizeAtTranslatedCode = host_platform::kIsX86_32 ? 12u : 8u;

}  // namespace berberis::config

#endif  // BERBERIS_RUNTIME_PRIMITIVES_CONFIG_H_