stack.cc revision 2cebb24bfc3247d3e9be138a3350106737455918 
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 "stack.h"
18
19#include "arch/context.h"
20#include "base/hex_dump.h"
21#include "entrypoints/runtime_asm_entrypoints.h"
22#include "mirror/art_method-inl.h"
23#include "mirror/class-inl.h"
24#include "mirror/object.h"
25#include "mirror/object-inl.h"
26#include "mirror/object_array-inl.h"
27#include "quick/quick_method_frame_info.h"
28#include "runtime.h"
29#include "thread.h"
30#include "thread_list.h"
31#include "verify_object-inl.h"
32#include "vmap_table.h"
33
34namespace art {
35
36mirror::Object* ShadowFrame::GetThisObject() const {
37  mirror::ArtMethod* m = GetMethod();
38  if (m->IsStatic()) {
39    return nullptr;
40  } else if (m->IsNative()) {
41    return GetVRegReference(0);
42  } else {
43    const DexFile::CodeItem* code_item = m->GetCodeItem();
44    CHECK(code_item != nullptr) << PrettyMethod(m);
45    uint16_t reg = code_item->registers_size_ - code_item->ins_size_;
46    return GetVRegReference(reg);
47  }
48}
49
50mirror::Object* ShadowFrame::GetThisObject(uint16_t num_ins) const {
51  mirror::ArtMethod* m = GetMethod();
52  if (m->IsStatic()) {
53    return nullptr;
54  } else {
55    return GetVRegReference(NumberOfVRegs() - num_ins);
56  }
57}
58
59size_t ManagedStack::NumJniShadowFrameReferences() const {
60  size_t count = 0;
61  for (const ManagedStack* current_fragment = this; current_fragment != nullptr;
62       current_fragment = current_fragment->GetLink()) {
63    for (ShadowFrame* current_frame = current_fragment->top_shadow_frame_; current_frame != nullptr;
64         current_frame = current_frame->GetLink()) {
65      if (current_frame->GetMethod()->IsNative()) {
66        // The JNI ShadowFrame only contains references. (For indirect reference.)
67        count += current_frame->NumberOfVRegs();
68      }
69    }
70  }
71  return count;
72}
73
74bool ManagedStack::ShadowFramesContain(StackReference<mirror::Object>* shadow_frame_entry) const {
75  for (const ManagedStack* current_fragment = this; current_fragment != nullptr;
76       current_fragment = current_fragment->GetLink()) {
77    for (ShadowFrame* current_frame = current_fragment->top_shadow_frame_; current_frame != nullptr;
78         current_frame = current_frame->GetLink()) {
79      if (current_frame->Contains(shadow_frame_entry)) {
80        return true;
81      }
82    }
83  }
84  return false;
85}
86
87StackVisitor::StackVisitor(Thread* thread, Context* context)
88    : thread_(thread), cur_shadow_frame_(nullptr),
89      cur_quick_frame_(nullptr), cur_quick_frame_pc_(0), num_frames_(0), cur_depth_(0),
90      context_(context) {
91  DCHECK(thread == Thread::Current() || thread->IsSuspended()) << *thread;
92}
93
94StackVisitor::StackVisitor(Thread* thread, Context* context, size_t num_frames)
95    : thread_(thread), cur_shadow_frame_(nullptr),
96      cur_quick_frame_(nullptr), cur_quick_frame_pc_(0), num_frames_(num_frames), cur_depth_(0),
97      context_(context) {
98  DCHECK(thread == Thread::Current() || thread->IsSuspended()) << *thread;
99}
100
101uint32_t StackVisitor::GetDexPc(bool abort_on_failure) const {
102  if (cur_shadow_frame_ != nullptr) {
103    return cur_shadow_frame_->GetDexPC();
104  } else if (cur_quick_frame_ != nullptr) {
105    return GetMethod()->ToDexPc(cur_quick_frame_pc_, abort_on_failure);
106  } else {
107    return 0;
108  }
109}
110
111extern "C" mirror::Object* artQuickGetProxyThisObject(StackReference<mirror::ArtMethod>* sp)
112    SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
113
114mirror::Object* StackVisitor::GetThisObject() const {
115  mirror::ArtMethod* m = GetMethod();
116  if (m->IsStatic()) {
117    return nullptr;
118  } else if (m->IsNative()) {
119    if (cur_quick_frame_ != nullptr) {
120      HandleScope* hs = reinterpret_cast<HandleScope*>(
121          reinterpret_cast<char*>(cur_quick_frame_) + m->GetHandleScopeOffset().SizeValue());
122      return hs->GetReference(0);
123    } else {
124      return cur_shadow_frame_->GetVRegReference(0);
125    }
126  } else if (m->IsProxyMethod()) {
127    if (cur_quick_frame_ != nullptr) {
128      return artQuickGetProxyThisObject(cur_quick_frame_);
129    } else {
130      return cur_shadow_frame_->GetVRegReference(0);
131    }
132  } else {
133    const DexFile::CodeItem* code_item = m->GetCodeItem();
134    if (code_item == nullptr) {
135      UNIMPLEMENTED(ERROR) << "Failed to determine this object of abstract or proxy method: "
136          << PrettyMethod(m);
137      return nullptr;
138    } else {
139      uint16_t reg = code_item->registers_size_ - code_item->ins_size_;
140      uint32_t value = 0;
141      bool success = GetVReg(m, reg, kReferenceVReg, &value);
142      // We currently always guarantee the `this` object is live throughout the method.
143      CHECK(success) << "Failed to read the this object in " << PrettyMethod(m);
144      return reinterpret_cast<mirror::Object*>(value);
145    }
146  }
147}
148
149size_t StackVisitor::GetNativePcOffset() const {
150  DCHECK(!IsShadowFrame());
151  return GetMethod()->NativeQuickPcOffset(cur_quick_frame_pc_);
152}
153
154bool StackVisitor::GetVReg(mirror::ArtMethod* m, uint16_t vreg, VRegKind kind,
155                           uint32_t* val) const {
156  if (cur_quick_frame_ != nullptr) {
157    DCHECK(context_ != nullptr);  // You can't reliably read registers without a context.
158    DCHECK(m == GetMethod());
159    if (m->IsOptimized(sizeof(void*))) {
160      return GetVRegFromOptimizedCode(m, vreg, kind, val);
161    } else {
162      return GetVRegFromQuickCode(m, vreg, kind, val);
163    }
164  } else {
165    DCHECK(cur_shadow_frame_ != nullptr);
166    *val = cur_shadow_frame_->GetVReg(vreg);
167    return true;
168  }
169}
170
171bool StackVisitor::GetVRegFromQuickCode(mirror::ArtMethod* m, uint16_t vreg, VRegKind kind,
172                                        uint32_t* val) const {
173  const void* code_pointer = m->GetQuickOatCodePointer(sizeof(void*));
174  DCHECK(code_pointer != nullptr);
175  const VmapTable vmap_table(m->GetVmapTable(code_pointer, sizeof(void*)));
176  QuickMethodFrameInfo frame_info = m->GetQuickFrameInfo(code_pointer);
177  uint32_t vmap_offset;
178  // TODO: IsInContext stops before spotting floating point registers.
179  if (vmap_table.IsInContext(vreg, kind, &vmap_offset)) {
180    bool is_float = (kind == kFloatVReg) || (kind == kDoubleLoVReg) || (kind == kDoubleHiVReg);
181    uint32_t spill_mask = is_float ? frame_info.FpSpillMask() : frame_info.CoreSpillMask();
182    uint32_t reg = vmap_table.ComputeRegister(spill_mask, vmap_offset, kind);
183    return GetRegisterIfAccessible(reg, kind, val);
184  } else {
185    const DexFile::CodeItem* code_item = m->GetCodeItem();
186    DCHECK(code_item != nullptr) << PrettyMethod(m);  // Can't be null or how would we compile
187                                                      // its instructions?
188    *val = *GetVRegAddrFromQuickCode(cur_quick_frame_, code_item, frame_info.CoreSpillMask(),
189                                     frame_info.FpSpillMask(), frame_info.FrameSizeInBytes(), vreg);
190    return true;
191  }
192}
193
194bool StackVisitor::GetVRegFromOptimizedCode(mirror::ArtMethod* m, uint16_t vreg, VRegKind kind,
195                                            uint32_t* val) const {
196  const void* code_pointer = m->GetQuickOatCodePointer(sizeof(void*));
197  DCHECK(code_pointer != nullptr);
198  uint32_t native_pc_offset = m->NativeQuickPcOffset(cur_quick_frame_pc_);
199  CodeInfo code_info = m->GetOptimizedCodeInfo();
200  StackMap stack_map = code_info.GetStackMapForNativePcOffset(native_pc_offset);
201  const DexFile::CodeItem* code_item = m->GetCodeItem();
202  DCHECK(code_item != nullptr) << PrettyMethod(m);  // Can't be null or how would we compile
203                                                    // its instructions?
204  DCHECK_LT(vreg, code_item->registers_size_);
205  uint16_t number_of_dex_registers = code_item->registers_size_;
206  DexRegisterMap dex_register_map =
207      code_info.GetDexRegisterMapOf(stack_map, number_of_dex_registers);
208  DexRegisterLocation::Kind location_kind =
209      dex_register_map.GetLocationKind(vreg, number_of_dex_registers, code_info);
210  switch (location_kind) {
211    case DexRegisterLocation::Kind::kInStack: {
212      const int32_t offset =
213          dex_register_map.GetStackOffsetInBytes(vreg, number_of_dex_registers, code_info);
214      const uint8_t* addr = reinterpret_cast<const uint8_t*>(cur_quick_frame_) + offset;
215      *val = *reinterpret_cast<const uint32_t*>(addr);
216      return true;
217    }
218    case DexRegisterLocation::Kind::kInRegister:
219    case DexRegisterLocation::Kind::kInFpuRegister: {
220      uint32_t reg = dex_register_map.GetMachineRegister(vreg, number_of_dex_registers, code_info);
221      return GetRegisterIfAccessible(reg, kind, val);
222    }
223    case DexRegisterLocation::Kind::kConstant:
224      *val = dex_register_map.GetConstant(vreg, number_of_dex_registers, code_info);
225      return true;
226    case DexRegisterLocation::Kind::kNone:
227      return false;
228    default:
229      LOG(FATAL)
230          << "Unexpected location kind"
231          << DexRegisterLocation::PrettyDescriptor(
232                dex_register_map.GetLocationInternalKind(vreg, number_of_dex_registers, code_info));
233      UNREACHABLE();
234  }
235}
236
237bool StackVisitor::GetRegisterIfAccessible(uint32_t reg, VRegKind kind, uint32_t* val) const {
238  const bool is_float = (kind == kFloatVReg) || (kind == kDoubleLoVReg) || (kind == kDoubleHiVReg);
239  if (!IsAccessibleRegister(reg, is_float)) {
240    return false;
241  }
242  uintptr_t ptr_val = GetRegister(reg, is_float);
243  const bool target64 = Is64BitInstructionSet(kRuntimeISA);
244  if (target64) {
245    const bool wide_lo = (kind == kLongLoVReg) || (kind == kDoubleLoVReg);
246    const bool wide_hi = (kind == kLongHiVReg) || (kind == kDoubleHiVReg);
247    int64_t value_long = static_cast<int64_t>(ptr_val);
248    if (wide_lo) {
249      ptr_val = static_cast<uintptr_t>(Low32Bits(value_long));
250    } else if (wide_hi) {
251      ptr_val = static_cast<uintptr_t>(High32Bits(value_long));
252    }
253  }
254  *val = ptr_val;
255  return true;
256}
257
258bool StackVisitor::GetVRegPair(mirror::ArtMethod* m, uint16_t vreg, VRegKind kind_lo,
259                               VRegKind kind_hi, uint64_t* val) const {
260  if (kind_lo == kLongLoVReg) {
261    DCHECK_EQ(kind_hi, kLongHiVReg);
262  } else if (kind_lo == kDoubleLoVReg) {
263    DCHECK_EQ(kind_hi, kDoubleHiVReg);
264  } else {
265    LOG(FATAL) << "Expected long or double: kind_lo=" << kind_lo << ", kind_hi=" << kind_hi;
266    UNREACHABLE();
267  }
268  if (cur_quick_frame_ != nullptr) {
269    DCHECK(context_ != nullptr);  // You can't reliably read registers without a context.
270    DCHECK(m == GetMethod());
271    if (m->IsOptimized(sizeof(void*))) {
272      return GetVRegPairFromOptimizedCode(m, vreg, kind_lo, kind_hi, val);
273    } else {
274      return GetVRegPairFromQuickCode(m, vreg, kind_lo, kind_hi, val);
275    }
276  } else {
277    DCHECK(cur_shadow_frame_ != nullptr);
278    *val = cur_shadow_frame_->GetVRegLong(vreg);
279    return true;
280  }
281}
282
283bool StackVisitor::GetVRegPairFromQuickCode(mirror::ArtMethod* m, uint16_t vreg, VRegKind kind_lo,
284                                            VRegKind kind_hi, uint64_t* val) const {
285  const void* code_pointer = m->GetQuickOatCodePointer(sizeof(void*));
286  DCHECK(code_pointer != nullptr);
287  const VmapTable vmap_table(m->GetVmapTable(code_pointer, sizeof(void*)));
288  QuickMethodFrameInfo frame_info = m->GetQuickFrameInfo(code_pointer);
289  uint32_t vmap_offset_lo, vmap_offset_hi;
290  // TODO: IsInContext stops before spotting floating point registers.
291  if (vmap_table.IsInContext(vreg, kind_lo, &vmap_offset_lo) &&
292      vmap_table.IsInContext(vreg + 1, kind_hi, &vmap_offset_hi)) {
293    bool is_float = (kind_lo == kDoubleLoVReg);
294    uint32_t spill_mask = is_float ? frame_info.FpSpillMask() : frame_info.CoreSpillMask();
295    uint32_t reg_lo = vmap_table.ComputeRegister(spill_mask, vmap_offset_lo, kind_lo);
296    uint32_t reg_hi = vmap_table.ComputeRegister(spill_mask, vmap_offset_hi, kind_hi);
297    return GetRegisterPairIfAccessible(reg_lo, reg_hi, kind_lo, val);
298  } else {
299    const DexFile::CodeItem* code_item = m->GetCodeItem();
300    DCHECK(code_item != nullptr) << PrettyMethod(m);  // Can't be null or how would we compile
301                                                      // its instructions?
302    uint32_t* addr = GetVRegAddrFromQuickCode(
303        cur_quick_frame_, code_item, frame_info.CoreSpillMask(),
304        frame_info.FpSpillMask(), frame_info.FrameSizeInBytes(), vreg);
305    *val = *reinterpret_cast<uint64_t*>(addr);
306    return true;
307  }
308}
309
310bool StackVisitor::GetVRegPairFromOptimizedCode(mirror::ArtMethod* m, uint16_t vreg,
311                                                VRegKind kind_lo, VRegKind kind_hi,
312                                                uint64_t* val) const {
313  uint32_t low_32bits;
314  uint32_t high_32bits;
315  bool success = GetVRegFromOptimizedCode(m, vreg, kind_lo, &low_32bits);
316  success &= GetVRegFromOptimizedCode(m, vreg + 1, kind_hi, &high_32bits);
317  if (success) {
318    *val = (static_cast<uint64_t>(high_32bits) << 32) | static_cast<uint64_t>(low_32bits);
319  }
320  return success;
321}
322
323bool StackVisitor::GetRegisterPairIfAccessible(uint32_t reg_lo, uint32_t reg_hi,
324                                               VRegKind kind_lo, uint64_t* val) const {
325  const bool is_float = (kind_lo == kDoubleLoVReg);
326  if (!IsAccessibleRegister(reg_lo, is_float) || !IsAccessibleRegister(reg_hi, is_float)) {
327    return false;
328  }
329  uintptr_t ptr_val_lo = GetRegister(reg_lo, is_float);
330  uintptr_t ptr_val_hi = GetRegister(reg_hi, is_float);
331  bool target64 = Is64BitInstructionSet(kRuntimeISA);
332  if (target64) {
333    int64_t value_long_lo = static_cast<int64_t>(ptr_val_lo);
334    int64_t value_long_hi = static_cast<int64_t>(ptr_val_hi);
335    ptr_val_lo = static_cast<uintptr_t>(Low32Bits(value_long_lo));
336    ptr_val_hi = static_cast<uintptr_t>(High32Bits(value_long_hi));
337  }
338  *val = (static_cast<uint64_t>(ptr_val_hi) << 32) | static_cast<uint32_t>(ptr_val_lo);
339  return true;
340}
341
342bool StackVisitor::SetVReg(mirror::ArtMethod* m, uint16_t vreg, uint32_t new_value,
343                           VRegKind kind) {
344  if (cur_quick_frame_ != nullptr) {
345      DCHECK(context_ != nullptr);  // You can't reliably write registers without a context.
346      DCHECK(m == GetMethod());
347      if (m->IsOptimized(sizeof(void*))) {
348        return SetVRegFromOptimizedCode(m, vreg, new_value, kind);
349      } else {
350        return SetVRegFromQuickCode(m, vreg, new_value, kind);
351      }
352    } else {
353      cur_shadow_frame_->SetVReg(vreg, new_value);
354      return true;
355    }
356}
357
358bool StackVisitor::SetVRegFromQuickCode(mirror::ArtMethod* m, uint16_t vreg, uint32_t new_value,
359                                        VRegKind kind) {
360  DCHECK(context_ != nullptr);  // You can't reliably write registers without a context.
361  DCHECK(m == GetMethod());
362  const void* code_pointer = m->GetQuickOatCodePointer(sizeof(void*));
363  DCHECK(code_pointer != nullptr);
364  const VmapTable vmap_table(m->GetVmapTable(code_pointer, sizeof(void*)));
365  QuickMethodFrameInfo frame_info = m->GetQuickFrameInfo(code_pointer);
366  uint32_t vmap_offset;
367  // TODO: IsInContext stops before spotting floating point registers.
368  if (vmap_table.IsInContext(vreg, kind, &vmap_offset)) {
369    bool is_float = (kind == kFloatVReg) || (kind == kDoubleLoVReg) || (kind == kDoubleHiVReg);
370    uint32_t spill_mask = is_float ? frame_info.FpSpillMask() : frame_info.CoreSpillMask();
371    uint32_t reg = vmap_table.ComputeRegister(spill_mask, vmap_offset, kind);
372    return SetRegisterIfAccessible(reg, new_value, kind);
373  } else {
374    const DexFile::CodeItem* code_item = m->GetCodeItem();
375    DCHECK(code_item != nullptr) << PrettyMethod(m);  // Can't be null or how would we compile
376                                                      // its instructions?
377    uint32_t* addr = GetVRegAddrFromQuickCode(
378        cur_quick_frame_, code_item, frame_info.CoreSpillMask(),
379        frame_info.FpSpillMask(), frame_info.FrameSizeInBytes(), vreg);
380    *addr = new_value;
381    return true;
382  }
383}
384
385bool StackVisitor::SetVRegFromOptimizedCode(mirror::ArtMethod* m, uint16_t vreg, uint32_t new_value,
386                                            VRegKind kind) {
387  const void* code_pointer = m->GetQuickOatCodePointer(sizeof(void*));
388  DCHECK(code_pointer != nullptr);
389  uint32_t native_pc_offset = m->NativeQuickPcOffset(cur_quick_frame_pc_);
390  CodeInfo code_info = m->GetOptimizedCodeInfo();
391  StackMap stack_map = code_info.GetStackMapForNativePcOffset(native_pc_offset);
392  const DexFile::CodeItem* code_item = m->GetCodeItem();
393  DCHECK(code_item != nullptr) << PrettyMethod(m);  // Can't be null or how would we compile
394                                                    // its instructions?
395  uint16_t number_of_dex_registers = code_item->registers_size_;
396  DCHECK_LT(vreg, number_of_dex_registers);
397  DexRegisterMap dex_register_map =
398      code_info.GetDexRegisterMapOf(stack_map, number_of_dex_registers);
399  DexRegisterLocation::Kind location_kind =
400      dex_register_map.GetLocationKind(vreg, number_of_dex_registers, code_info);
401  uint32_t dex_pc = m->ToDexPc(cur_quick_frame_pc_, false);
402  switch (location_kind) {
403    case DexRegisterLocation::Kind::kInStack: {
404      const int32_t offset =
405          dex_register_map.GetStackOffsetInBytes(vreg, number_of_dex_registers, code_info);
406      uint8_t* addr = reinterpret_cast<uint8_t*>(cur_quick_frame_) + offset;
407      *reinterpret_cast<uint32_t*>(addr) = new_value;
408      return true;
409    }
410    case DexRegisterLocation::Kind::kInRegister:
411    case DexRegisterLocation::Kind::kInFpuRegister: {
412      uint32_t reg = dex_register_map.GetMachineRegister(vreg, number_of_dex_registers, code_info);
413      return SetRegisterIfAccessible(reg, new_value, kind);
414    }
415    case DexRegisterLocation::Kind::kConstant:
416      LOG(ERROR) << StringPrintf("Cannot change value of DEX register v%u used as a constant at "
417                                 "DEX pc 0x%x (native pc 0x%x) of method %s",
418                                 vreg, dex_pc, native_pc_offset,
419                                 PrettyMethod(cur_quick_frame_->AsMirrorPtr()).c_str());
420      return false;
421    case DexRegisterLocation::Kind::kNone:
422      LOG(ERROR) << StringPrintf("No location for DEX register v%u at DEX pc 0x%x "
423                                 "(native pc 0x%x) of method %s",
424                                 vreg, dex_pc, native_pc_offset,
425                                 PrettyMethod(cur_quick_frame_->AsMirrorPtr()).c_str());
426      return false;
427    default:
428      LOG(FATAL) << StringPrintf("Unknown location for DEX register v%u at DEX pc 0x%x "
429                                 "(native pc 0x%x) of method %s",
430                                 vreg, dex_pc, native_pc_offset,
431                                 PrettyMethod(cur_quick_frame_->AsMirrorPtr()).c_str());
432      UNREACHABLE();
433  }
434}
435
436bool StackVisitor::SetRegisterIfAccessible(uint32_t reg, uint32_t new_value, VRegKind kind) {
437  const bool is_float = (kind == kFloatVReg) || (kind == kDoubleLoVReg) || (kind == kDoubleHiVReg);
438  if (!IsAccessibleRegister(reg, is_float)) {
439    return false;
440  }
441  const bool target64 = Is64BitInstructionSet(kRuntimeISA);
442
443  // Create a new value that can hold both low 32 and high 32 bits, in
444  // case we are running 64 bits.
445  uintptr_t full_new_value = new_value;
446  // Deal with 32 or 64-bit wide registers in a way that builds on all targets.
447  if (target64) {
448    bool wide_lo = (kind == kLongLoVReg) || (kind == kDoubleLoVReg);
449    bool wide_hi = (kind == kLongHiVReg) || (kind == kDoubleHiVReg);
450    if (wide_lo || wide_hi) {
451      uintptr_t old_reg_val = GetRegister(reg, is_float);
452      uint64_t new_vreg_portion = static_cast<uint64_t>(new_value);
453      uint64_t old_reg_val_as_wide = static_cast<uint64_t>(old_reg_val);
454      uint64_t mask = 0xffffffff;
455      if (wide_lo) {
456        mask = mask << 32;
457      } else {
458        new_vreg_portion = new_vreg_portion << 32;
459      }
460      full_new_value = static_cast<uintptr_t>((old_reg_val_as_wide & mask) | new_vreg_portion);
461    }
462  }
463  SetRegister(reg, full_new_value, is_float);
464  return true;
465}
466
467bool StackVisitor::SetVRegPair(mirror::ArtMethod* m, uint16_t vreg, uint64_t new_value,
468                               VRegKind kind_lo, VRegKind kind_hi) {
469  if (kind_lo == kLongLoVReg) {
470    DCHECK_EQ(kind_hi, kLongHiVReg);
471  } else if (kind_lo == kDoubleLoVReg) {
472    DCHECK_EQ(kind_hi, kDoubleHiVReg);
473  } else {
474    LOG(FATAL) << "Expected long or double: kind_lo=" << kind_lo << ", kind_hi=" << kind_hi;
475  }
476  if (cur_quick_frame_ != nullptr) {
477    DCHECK(context_ != nullptr);  // You can't reliably write registers without a context.
478    DCHECK(m == GetMethod());
479    if (m->IsOptimized(sizeof(void*))) {
480      return SetVRegPairFromOptimizedCode(m, vreg, new_value, kind_lo, kind_hi);
481    } else {
482      return SetVRegPairFromQuickCode(m, vreg, new_value, kind_lo, kind_hi);
483    }
484  } else {
485    DCHECK(cur_shadow_frame_ != nullptr);
486    cur_shadow_frame_->SetVRegLong(vreg, new_value);
487    return true;
488  }
489}
490
491bool StackVisitor::SetVRegPairFromQuickCode(
492    mirror::ArtMethod* m, uint16_t vreg, uint64_t new_value, VRegKind kind_lo, VRegKind kind_hi) {
493  const void* code_pointer = m->GetQuickOatCodePointer(sizeof(void*));
494  DCHECK(code_pointer != nullptr);
495  const VmapTable vmap_table(m->GetVmapTable(code_pointer, sizeof(void*)));
496  QuickMethodFrameInfo frame_info = m->GetQuickFrameInfo(code_pointer);
497  uint32_t vmap_offset_lo, vmap_offset_hi;
498  // TODO: IsInContext stops before spotting floating point registers.
499  if (vmap_table.IsInContext(vreg, kind_lo, &vmap_offset_lo) &&
500      vmap_table.IsInContext(vreg + 1, kind_hi, &vmap_offset_hi)) {
501    bool is_float = (kind_lo == kDoubleLoVReg);
502    uint32_t spill_mask = is_float ? frame_info.FpSpillMask() : frame_info.CoreSpillMask();
503    uint32_t reg_lo = vmap_table.ComputeRegister(spill_mask, vmap_offset_lo, kind_lo);
504    uint32_t reg_hi = vmap_table.ComputeRegister(spill_mask, vmap_offset_hi, kind_hi);
505    return SetRegisterPairIfAccessible(reg_lo, reg_hi, new_value, is_float);
506  } else {
507    const DexFile::CodeItem* code_item = m->GetCodeItem();
508    DCHECK(code_item != nullptr) << PrettyMethod(m);  // Can't be null or how would we compile
509                                                      // its instructions?
510    uint32_t* addr = GetVRegAddrFromQuickCode(
511        cur_quick_frame_, code_item, frame_info.CoreSpillMask(),
512        frame_info.FpSpillMask(), frame_info.FrameSizeInBytes(), vreg);
513    *reinterpret_cast<uint64_t*>(addr) = new_value;
514    return true;
515  }
516}
517
518bool StackVisitor::SetVRegPairFromOptimizedCode(
519    mirror::ArtMethod* m, uint16_t vreg, uint64_t new_value, VRegKind kind_lo, VRegKind kind_hi) {
520  uint32_t low_32bits = Low32Bits(new_value);
521  uint32_t high_32bits = High32Bits(new_value);
522  bool success = SetVRegFromOptimizedCode(m, vreg, low_32bits, kind_lo);
523  success &= SetVRegFromOptimizedCode(m, vreg + 1, high_32bits, kind_hi);
524  return success;
525}
526
527bool StackVisitor::SetRegisterPairIfAccessible(uint32_t reg_lo, uint32_t reg_hi,
528                                               uint64_t new_value, bool is_float) {
529  if (!IsAccessibleRegister(reg_lo, is_float) || !IsAccessibleRegister(reg_hi, is_float)) {
530    return false;
531  }
532  uintptr_t new_value_lo = static_cast<uintptr_t>(new_value & 0xFFFFFFFF);
533  uintptr_t new_value_hi = static_cast<uintptr_t>(new_value >> 32);
534  bool target64 = Is64BitInstructionSet(kRuntimeISA);
535  // Deal with 32 or 64-bit wide registers in a way that builds on all targets.
536  if (target64) {
537    DCHECK_EQ(reg_lo, reg_hi);
538    SetRegister(reg_lo, new_value, is_float);
539  } else {
540    SetRegister(reg_lo, new_value_lo, is_float);
541    SetRegister(reg_hi, new_value_hi, is_float);
542  }
543  return true;
544}
545
546bool StackVisitor::IsAccessibleGPR(uint32_t reg) const {
547  DCHECK(context_ != nullptr);
548  return context_->IsAccessibleGPR(reg);
549}
550
551uintptr_t* StackVisitor::GetGPRAddress(uint32_t reg) const {
552  DCHECK(cur_quick_frame_ != nullptr) << "This is a quick frame routine";
553  DCHECK(context_ != nullptr);
554  return context_->GetGPRAddress(reg);
555}
556
557uintptr_t StackVisitor::GetGPR(uint32_t reg) const {
558  DCHECK(cur_quick_frame_ != nullptr) << "This is a quick frame routine";
559  DCHECK(context_ != nullptr);
560  return context_->GetGPR(reg);
561}
562
563void StackVisitor::SetGPR(uint32_t reg, uintptr_t value) {
564  DCHECK(cur_quick_frame_ != nullptr) << "This is a quick frame routine";
565  DCHECK(context_ != nullptr);
566  context_->SetGPR(reg, value);
567}
568
569bool StackVisitor::IsAccessibleFPR(uint32_t reg) const {
570  DCHECK(context_ != nullptr);
571  return context_->IsAccessibleFPR(reg);
572}
573
574uintptr_t StackVisitor::GetFPR(uint32_t reg) const {
575  DCHECK(cur_quick_frame_ != nullptr) << "This is a quick frame routine";
576  DCHECK(context_ != nullptr);
577  return context_->GetFPR(reg);
578}
579
580void StackVisitor::SetFPR(uint32_t reg, uintptr_t value) {
581  DCHECK(cur_quick_frame_ != nullptr) << "This is a quick frame routine";
582  DCHECK(context_ != nullptr);
583  context_->SetFPR(reg, value);
584}
585
586uintptr_t StackVisitor::GetReturnPc() const {
587  uint8_t* sp = reinterpret_cast<uint8_t*>(GetCurrentQuickFrame());
588  DCHECK(sp != nullptr);
589  uint8_t* pc_addr = sp + GetMethod()->GetReturnPcOffset().SizeValue();
590  return *reinterpret_cast<uintptr_t*>(pc_addr);
591}
592
593void StackVisitor::SetReturnPc(uintptr_t new_ret_pc) {
594  uint8_t* sp = reinterpret_cast<uint8_t*>(GetCurrentQuickFrame());
595  CHECK(sp != nullptr);
596  uint8_t* pc_addr = sp + GetMethod()->GetReturnPcOffset().SizeValue();
597  *reinterpret_cast<uintptr_t*>(pc_addr) = new_ret_pc;
598}
599
600size_t StackVisitor::ComputeNumFrames(Thread* thread) {
601  struct NumFramesVisitor : public StackVisitor {
602    explicit NumFramesVisitor(Thread* thread_in)
603        : StackVisitor(thread_in, nullptr), frames(0) {}
604
605    bool VisitFrame() OVERRIDE {
606      frames++;
607      return true;
608    }
609
610    size_t frames;
611  };
612  NumFramesVisitor visitor(thread);
613  visitor.WalkStack(true);
614  return visitor.frames;
615}
616
617bool StackVisitor::GetNextMethodAndDexPc(mirror::ArtMethod** next_method, uint32_t* next_dex_pc) {
618  struct HasMoreFramesVisitor : public StackVisitor {
619    explicit HasMoreFramesVisitor(Thread* thread, size_t num_frames, size_t frame_height)
620        : StackVisitor(thread, nullptr, num_frames), frame_height_(frame_height),
621          found_frame_(false), has_more_frames_(false), next_method_(nullptr), next_dex_pc_(0) {
622    }
623
624    bool VisitFrame() OVERRIDE SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
625      if (found_frame_) {
626        mirror::ArtMethod* method = GetMethod();
627        if (method != nullptr && !method->IsRuntimeMethod()) {
628          has_more_frames_ = true;
629          next_method_ = method;
630          next_dex_pc_ = GetDexPc();
631          return false;  // End stack walk once next method is found.
632        }
633      } else if (GetFrameHeight() == frame_height_) {
634        found_frame_ = true;
635      }
636      return true;
637    }
638
639    size_t frame_height_;
640    bool found_frame_;
641    bool has_more_frames_;
642    mirror::ArtMethod* next_method_;
643    uint32_t next_dex_pc_;
644  };
645  HasMoreFramesVisitor visitor(thread_, GetNumFrames(), GetFrameHeight());
646  visitor.WalkStack(true);
647  *next_method = visitor.next_method_;
648  *next_dex_pc = visitor.next_dex_pc_;
649  return visitor.has_more_frames_;
650}
651
652void StackVisitor::DescribeStack(Thread* thread) {
653  struct DescribeStackVisitor : public StackVisitor {
654    explicit DescribeStackVisitor(Thread* thread_in)
655        : StackVisitor(thread_in, nullptr) {}
656
657    bool VisitFrame() OVERRIDE SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
658      LOG(INFO) << "Frame Id=" << GetFrameId() << " " << DescribeLocation();
659      return true;
660    }
661  };
662  DescribeStackVisitor visitor(thread);
663  visitor.WalkStack(true);
664}
665
666std::string StackVisitor::DescribeLocation() const {
667  std::string result("Visiting method '");
668  mirror::ArtMethod* m = GetMethod();
669  if (m == nullptr) {
670    return "upcall";
671  }
672  result += PrettyMethod(m);
673  result += StringPrintf("' at dex PC 0x%04x", GetDexPc());
674  if (!IsShadowFrame()) {
675    result += StringPrintf(" (native PC %p)", reinterpret_cast<void*>(GetCurrentQuickFramePc()));
676  }
677  return result;
678}
679
680static instrumentation::InstrumentationStackFrame& GetInstrumentationStackFrame(Thread* thread,
681                                                                                uint32_t depth) {
682  CHECK_LT(depth, thread->GetInstrumentationStack()->size());
683  return thread->GetInstrumentationStack()->at(depth);
684}
685
686void StackVisitor::SanityCheckFrame() const {
687  if (kIsDebugBuild) {
688    mirror::ArtMethod* method = GetMethod();
689    CHECK_EQ(method->GetClass(), mirror::ArtMethod::GetJavaLangReflectArtMethod());
690    if (cur_quick_frame_ != nullptr) {
691      method->AssertPcIsWithinQuickCode(cur_quick_frame_pc_);
692      // Frame sanity.
693      size_t frame_size = method->GetFrameSizeInBytes();
694      CHECK_NE(frame_size, 0u);
695      // A rough guess at an upper size we expect to see for a frame.
696      // 256 registers
697      // 2 words HandleScope overhead
698      // 3+3 register spills
699      // TODO: this seems architecture specific for the case of JNI frames.
700      // TODO: 083-compiler-regressions ManyFloatArgs shows this estimate is wrong.
701      // const size_t kMaxExpectedFrameSize = (256 + 2 + 3 + 3) * sizeof(word);
702      const size_t kMaxExpectedFrameSize = 2 * KB;
703      CHECK_LE(frame_size, kMaxExpectedFrameSize);
704      size_t return_pc_offset = method->GetReturnPcOffset().SizeValue();
705      CHECK_LT(return_pc_offset, frame_size);
706    }
707  }
708}
709
710void StackVisitor::WalkStack(bool include_transitions) {
711  DCHECK(thread_ == Thread::Current() || thread_->IsSuspended());
712  CHECK_EQ(cur_depth_, 0U);
713  bool exit_stubs_installed = Runtime::Current()->GetInstrumentation()->AreExitStubsInstalled();
714  uint32_t instrumentation_stack_depth = 0;
715
716  for (const ManagedStack* current_fragment = thread_->GetManagedStack();
717       current_fragment != nullptr; current_fragment = current_fragment->GetLink()) {
718    cur_shadow_frame_ = current_fragment->GetTopShadowFrame();
719    cur_quick_frame_ = current_fragment->GetTopQuickFrame();
720    cur_quick_frame_pc_ = 0;
721
722    if (cur_quick_frame_ != nullptr) {  // Handle quick stack frames.
723      // Can't be both a shadow and a quick fragment.
724      DCHECK(current_fragment->GetTopShadowFrame() == nullptr);
725      mirror::ArtMethod* method = cur_quick_frame_->AsMirrorPtr();
726      while (method != nullptr) {
727        SanityCheckFrame();
728        bool should_continue = VisitFrame();
729        if (UNLIKELY(!should_continue)) {
730          return;
731        }
732
733        if (context_ != nullptr) {
734          context_->FillCalleeSaves(*this);
735        }
736        size_t frame_size = method->GetFrameSizeInBytes();
737        // Compute PC for next stack frame from return PC.
738        size_t return_pc_offset = method->GetReturnPcOffset(frame_size).SizeValue();
739        uint8_t* return_pc_addr = reinterpret_cast<uint8_t*>(cur_quick_frame_) + return_pc_offset;
740        uintptr_t return_pc = *reinterpret_cast<uintptr_t*>(return_pc_addr);
741        if (UNLIKELY(exit_stubs_installed)) {
742          // While profiling, the return pc is restored from the side stack, except when walking
743          // the stack for an exception where the side stack will be unwound in VisitFrame.
744          if (reinterpret_cast<uintptr_t>(GetQuickInstrumentationExitPc()) == return_pc) {
745            const instrumentation::InstrumentationStackFrame& instrumentation_frame =
746                GetInstrumentationStackFrame(thread_, instrumentation_stack_depth);
747            instrumentation_stack_depth++;
748            if (GetMethod() == Runtime::Current()->GetCalleeSaveMethod(Runtime::kSaveAll)) {
749              // Skip runtime save all callee frames which are used to deliver exceptions.
750            } else if (instrumentation_frame.interpreter_entry_) {
751              mirror::ArtMethod* callee =
752                  Runtime::Current()->GetCalleeSaveMethod(Runtime::kRefsAndArgs);
753              CHECK_EQ(GetMethod(), callee) << "Expected: " << PrettyMethod(callee) << " Found: "
754                                            << PrettyMethod(GetMethod());
755            } else if (instrumentation_frame.method_ != GetMethod()) {
756              LOG(FATAL)  << "Expected: " << PrettyMethod(instrumentation_frame.method_)
757                          << " Found: " << PrettyMethod(GetMethod());
758            }
759            if (num_frames_ != 0) {
760              // Check agreement of frame Ids only if num_frames_ is computed to avoid infinite
761              // recursion.
762              CHECK(instrumentation_frame.frame_id_ == GetFrameId())
763                    << "Expected: " << instrumentation_frame.frame_id_
764                    << " Found: " << GetFrameId();
765            }
766            return_pc = instrumentation_frame.return_pc_;
767          }
768        }
769        cur_quick_frame_pc_ = return_pc;
770        uint8_t* next_frame = reinterpret_cast<uint8_t*>(cur_quick_frame_) + frame_size;
771        cur_quick_frame_ = reinterpret_cast<StackReference<mirror::ArtMethod>*>(next_frame);
772        cur_depth_++;
773        method = cur_quick_frame_->AsMirrorPtr();
774      }
775    } else if (cur_shadow_frame_ != nullptr) {
776      do {
777        SanityCheckFrame();
778        bool should_continue = VisitFrame();
779        if (UNLIKELY(!should_continue)) {
780          return;
781        }
782        cur_depth_++;
783        cur_shadow_frame_ = cur_shadow_frame_->GetLink();
784      } while (cur_shadow_frame_ != nullptr);
785    }
786    if (include_transitions) {
787      bool should_continue = VisitFrame();
788      if (!should_continue) {
789        return;
790      }
791    }
792    cur_depth_++;
793  }
794  if (num_frames_ != 0) {
795    CHECK_EQ(cur_depth_, num_frames_);
796  }
797}
798
799void JavaFrameRootInfo::Describe(std::ostream& os) const {
800  const StackVisitor* visitor = stack_visitor_;
801  CHECK(visitor != nullptr);
802  os << "Type=" << GetType() << " thread_id=" << GetThreadId() << " location=" <<
803      visitor->DescribeLocation() << " vreg=" << vreg_;
804}
805
806}  // namespace art
807