1 /*
2 * Copyright (C) 2020 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_RUNTIME_ARCH_ARM64_JNI_FRAME_ARM64_H_
18 #define ART_RUNTIME_ARCH_ARM64_JNI_FRAME_ARM64_H_
19
20 #include <string.h>
21
22 #include "arch/instruction_set.h"
23 #include "base/bit_utils.h"
24 #include "base/globals.h"
25 #include "base/logging.h"
26 #include "base/macros.h"
27
28 namespace art HIDDEN {
29 namespace arm64 {
30
31 constexpr size_t kFramePointerSize = static_cast<size_t>(PointerSize::k64);
32 static_assert(kArm64PointerSize == PointerSize::k64, "Unexpected ARM64 pointer size");
33
34 // The AAPCS64 requires 16-byte alignment. This is the same as the Managed ABI stack alignment.
35 static constexpr size_t kAapcs64StackAlignment = 16u;
36 static_assert(kAapcs64StackAlignment == kStackAlignment);
37
38 // Up to how many float-like (float, double) args can be in registers.
39 // The rest of the args must go on the stack.
40 constexpr size_t kMaxFloatOrDoubleRegisterArguments = 8u;
41 // Up to how many integer-like (pointers, objects, longs, int, short, bool, etc) args can be
42 // in registers. The rest of the args must go on the stack.
43 constexpr size_t kMaxIntLikeRegisterArguments = 8u;
44
45 // Get the size of the arguments for a native call.
GetNativeOutArgsSize(size_t num_fp_args,size_t num_non_fp_args)46 inline size_t GetNativeOutArgsSize(size_t num_fp_args, size_t num_non_fp_args) {
47 // Account for FP arguments passed through v0-v7.
48 size_t num_stack_fp_args =
49 num_fp_args - std::min(kMaxFloatOrDoubleRegisterArguments, num_fp_args);
50 // Account for other (integer and pointer) arguments passed through GPR (x0-x7).
51 size_t num_stack_non_fp_args =
52 num_non_fp_args - std::min(kMaxIntLikeRegisterArguments, num_non_fp_args);
53 // Each stack argument takes 8 bytes.
54 return (num_stack_fp_args + num_stack_non_fp_args) * static_cast<size_t>(kArm64PointerSize);
55 }
56
57 // Get stack args size for @CriticalNative method calls.
GetCriticalNativeCallArgsSize(std::string_view shorty)58 inline size_t GetCriticalNativeCallArgsSize(std::string_view shorty) {
59 size_t num_fp_args =
60 std::count_if(shorty.begin() + 1, shorty.end(), [](char c) { return c == 'F' || c == 'D'; });
61 size_t num_non_fp_args = shorty.length() - 1u - num_fp_args;
62
63 return GetNativeOutArgsSize(num_fp_args, num_non_fp_args);
64 }
65
66 // Get the frame size for @CriticalNative method stub.
67 // This must match the size of the extra frame emitted by the compiler at the native call site.
GetCriticalNativeStubFrameSize(std::string_view shorty)68 inline size_t GetCriticalNativeStubFrameSize(std::string_view shorty) {
69 // The size of outgoing arguments.
70 size_t size = GetCriticalNativeCallArgsSize(shorty);
71
72 // We can make a tail call if there are no stack args and we do not need
73 // to extend the result. Otherwise, add space for return PC.
74 if (size != 0u || shorty[0] == 'B' || shorty[0] == 'C' || shorty[0] == 'S' || shorty[0] == 'Z') {
75 size += kFramePointerSize; // We need to spill LR with the args.
76 }
77 return RoundUp(size, kAapcs64StackAlignment);
78 }
79
80 // Get the frame size for direct call to a @CriticalNative method.
81 // This must match the size of the frame emitted by the JNI compiler at the native call site.
GetCriticalNativeDirectCallFrameSize(std::string_view shorty)82 inline size_t GetCriticalNativeDirectCallFrameSize(std::string_view shorty) {
83 // The size of outgoing arguments.
84 size_t size = GetCriticalNativeCallArgsSize(shorty);
85
86 // No return PC to save, zero- and sign-extension are handled by the caller.
87 return RoundUp(size, kAapcs64StackAlignment);
88 }
89
90 } // namespace arm64
91 } // namespace art
92
93 #endif // ART_RUNTIME_ARCH_ARM64_JNI_FRAME_ARM64_H_
94