1/*
2 * Copyright (C) 2011 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#include "context_arm.h"
18
19#include "mirror/art_method-inl.h"
20#include "mirror/object-inl.h"
21#include "quick/quick_method_frame_info.h"
22#include "stack.h"
23#include "thread.h"
24
25namespace art {
26namespace arm {
27
28static constexpr uint32_t gZero = 0;
29
30void ArmContext::Reset() {
31  for (size_t i = 0; i < kNumberOfCoreRegisters; i++) {
32    gprs_[i] = nullptr;
33  }
34  for (size_t i = 0; i < kNumberOfSRegisters; i++) {
35    fprs_[i] = nullptr;
36  }
37  gprs_[SP] = &sp_;
38  gprs_[PC] = &pc_;
39  // Initialize registers with easy to spot debug values.
40  sp_ = ArmContext::kBadGprBase + SP;
41  pc_ = ArmContext::kBadGprBase + PC;
42}
43
44void ArmContext::FillCalleeSaves(const StackVisitor& fr) {
45  mirror::ArtMethod* method = fr.GetMethod();
46  const QuickMethodFrameInfo frame_info = method->GetQuickFrameInfo();
47  size_t spill_count = POPCOUNT(frame_info.CoreSpillMask());
48  size_t fp_spill_count = POPCOUNT(frame_info.FpSpillMask());
49  if (spill_count > 0) {
50    // Lowest number spill is farthest away, walk registers and fill into context
51    int j = 1;
52    for (size_t i = 0; i < kNumberOfCoreRegisters; i++) {
53      if (((frame_info.CoreSpillMask() >> i) & 1) != 0) {
54        gprs_[i] = fr.CalleeSaveAddress(spill_count - j, frame_info.FrameSizeInBytes());
55        j++;
56      }
57    }
58  }
59  if (fp_spill_count > 0) {
60    // Lowest number spill is farthest away, walk registers and fill into context
61    int j = 1;
62    for (size_t i = 0; i < kNumberOfSRegisters; i++) {
63      if (((frame_info.FpSpillMask() >> i) & 1) != 0) {
64        fprs_[i] = fr.CalleeSaveAddress(spill_count + fp_spill_count - j,
65                                        frame_info.FrameSizeInBytes());
66        j++;
67      }
68    }
69  }
70}
71
72bool ArmContext::SetGPR(uint32_t reg, uintptr_t value) {
73  DCHECK_LT(reg, static_cast<uint32_t>(kNumberOfCoreRegisters));
74  DCHECK_NE(gprs_[reg], &gZero);  // Can't overwrite this static value since they are never reset.
75  if (gprs_[reg] != nullptr) {
76    *gprs_[reg] = value;
77    return true;
78  } else {
79    return false;
80  }
81}
82
83bool ArmContext::SetFPR(uint32_t reg, uintptr_t value) {
84  DCHECK_LT(reg, static_cast<uint32_t>(kNumberOfSRegisters));
85  DCHECK_NE(fprs_[reg], &gZero);  // Can't overwrite this static value since they are never reset.
86  if (fprs_[reg] != nullptr) {
87    *fprs_[reg] = value;
88    return true;
89  } else {
90    return false;
91  }
92}
93
94void ArmContext::SmashCallerSaves() {
95  // This needs to be 0 because we want a null/zero return value.
96  gprs_[R0] = const_cast<uint32_t*>(&gZero);
97  gprs_[R1] = const_cast<uint32_t*>(&gZero);
98  gprs_[R2] = nullptr;
99  gprs_[R3] = nullptr;
100}
101
102extern "C" void art_quick_do_long_jump(uint32_t*, uint32_t*);
103
104void ArmContext::DoLongJump() {
105  uintptr_t gprs[kNumberOfCoreRegisters];
106  uint32_t fprs[kNumberOfSRegisters];
107  for (size_t i = 0; i < kNumberOfCoreRegisters; ++i) {
108    gprs[i] = gprs_[i] != nullptr ? *gprs_[i] : ArmContext::kBadGprBase + i;
109  }
110  for (size_t i = 0; i < kNumberOfSRegisters; ++i) {
111    fprs[i] = fprs_[i] != nullptr ? *fprs_[i] : ArmContext::kBadFprBase + i;
112  }
113  DCHECK_EQ(reinterpret_cast<uintptr_t>(Thread::Current()), gprs[TR]);
114  art_quick_do_long_jump(gprs, fprs);
115}
116
117}  // namespace arm
118}  // namespace art
119