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      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 "art_method-inl.h"
     21 #include "base/hex_dump.h"
     22 #include "entrypoints/entrypoint_utils-inl.h"
     23 #include "entrypoints/runtime_asm_entrypoints.h"
     24 #include "gc/space/image_space.h"
     25 #include "gc/space/space-inl.h"
     26 #include "jit/jit.h"
     27 #include "jit/jit_code_cache.h"
     28 #include "linear_alloc.h"
     29 #include "mirror/class-inl.h"
     30 #include "mirror/object-inl.h"
     31 #include "mirror/object_array-inl.h"
     32 #include "oat_quick_method_header.h"
     33 #include "quick/quick_method_frame_info.h"
     34 #include "runtime.h"
     35 #include "thread.h"
     36 #include "thread_list.h"
     37 #include "verify_object-inl.h"
     38 
     39 namespace art {
     40 
     41 static constexpr bool kDebugStackWalk = false;
     42 
     43 mirror::Object* ShadowFrame::GetThisObject() const {
     44   ArtMethod* m = GetMethod();
     45   if (m->IsStatic()) {
     46     return nullptr;
     47   } else if (m->IsNative()) {
     48     return GetVRegReference(0);
     49   } else {
     50     const DexFile::CodeItem* code_item = m->GetCodeItem();
     51     CHECK(code_item != nullptr) << PrettyMethod(m);
     52     uint16_t reg = code_item->registers_size_ - code_item->ins_size_;
     53     return GetVRegReference(reg);
     54   }
     55 }
     56 
     57 mirror::Object* ShadowFrame::GetThisObject(uint16_t num_ins) const {
     58   ArtMethod* m = GetMethod();
     59   if (m->IsStatic()) {
     60     return nullptr;
     61   } else {
     62     return GetVRegReference(NumberOfVRegs() - num_ins);
     63   }
     64 }
     65 
     66 size_t ManagedStack::NumJniShadowFrameReferences() const {
     67   size_t count = 0;
     68   for (const ManagedStack* current_fragment = this; current_fragment != nullptr;
     69        current_fragment = current_fragment->GetLink()) {
     70     for (ShadowFrame* current_frame = current_fragment->top_shadow_frame_; current_frame != nullptr;
     71          current_frame = current_frame->GetLink()) {
     72       if (current_frame->GetMethod()->IsNative()) {
     73         // The JNI ShadowFrame only contains references. (For indirect reference.)
     74         count += current_frame->NumberOfVRegs();
     75       }
     76     }
     77   }
     78   return count;
     79 }
     80 
     81 bool ManagedStack::ShadowFramesContain(StackReference<mirror::Object>* shadow_frame_entry) const {
     82   for (const ManagedStack* current_fragment = this; current_fragment != nullptr;
     83        current_fragment = current_fragment->GetLink()) {
     84     for (ShadowFrame* current_frame = current_fragment->top_shadow_frame_; current_frame != nullptr;
     85          current_frame = current_frame->GetLink()) {
     86       if (current_frame->Contains(shadow_frame_entry)) {
     87         return true;
     88       }
     89     }
     90   }
     91   return false;
     92 }
     93 
     94 StackVisitor::StackVisitor(Thread* thread, Context* context, StackWalkKind walk_kind)
     95     : StackVisitor(thread, context, walk_kind, 0) {}
     96 
     97 StackVisitor::StackVisitor(Thread* thread,
     98                            Context* context,
     99                            StackWalkKind walk_kind,
    100                            size_t num_frames)
    101     : thread_(thread),
    102       walk_kind_(walk_kind),
    103       cur_shadow_frame_(nullptr),
    104       cur_quick_frame_(nullptr),
    105       cur_quick_frame_pc_(0),
    106       cur_oat_quick_method_header_(nullptr),
    107       num_frames_(num_frames),
    108       cur_depth_(0),
    109       current_inlining_depth_(0),
    110       context_(context) {
    111   DCHECK(thread == Thread::Current() || thread->IsSuspended()) << *thread;
    112 }
    113 
    114 InlineInfo StackVisitor::GetCurrentInlineInfo() const {
    115   const OatQuickMethodHeader* method_header = GetCurrentOatQuickMethodHeader();
    116   uint32_t native_pc_offset = method_header->NativeQuickPcOffset(cur_quick_frame_pc_);
    117   CodeInfo code_info = method_header->GetOptimizedCodeInfo();
    118   CodeInfoEncoding encoding = code_info.ExtractEncoding();
    119   StackMap stack_map = code_info.GetStackMapForNativePcOffset(native_pc_offset, encoding);
    120   DCHECK(stack_map.IsValid());
    121   return code_info.GetInlineInfoOf(stack_map, encoding);
    122 }
    123 
    124 ArtMethod* StackVisitor::GetMethod() const {
    125   if (cur_shadow_frame_ != nullptr) {
    126     return cur_shadow_frame_->GetMethod();
    127   } else if (cur_quick_frame_ != nullptr) {
    128     if (IsInInlinedFrame()) {
    129       size_t depth_in_stack_map = current_inlining_depth_ - 1;
    130       InlineInfo inline_info = GetCurrentInlineInfo();
    131       const OatQuickMethodHeader* method_header = GetCurrentOatQuickMethodHeader();
    132       CodeInfoEncoding encoding = method_header->GetOptimizedCodeInfo().ExtractEncoding();
    133       DCHECK(walk_kind_ != StackWalkKind::kSkipInlinedFrames);
    134       bool allow_resolve = walk_kind_ != StackWalkKind::kIncludeInlinedFramesNoResolve;
    135       return allow_resolve
    136           ? GetResolvedMethod<true>(*GetCurrentQuickFrame(),
    137                                     inline_info,
    138                                     encoding.inline_info_encoding,
    139                                     depth_in_stack_map)
    140           : GetResolvedMethod<false>(*GetCurrentQuickFrame(),
    141                                      inline_info,
    142                                      encoding.inline_info_encoding,
    143                                      depth_in_stack_map);
    144     } else {
    145       return *cur_quick_frame_;
    146     }
    147   }
    148   return nullptr;
    149 }
    150 
    151 uint32_t StackVisitor::GetDexPc(bool abort_on_failure) const {
    152   if (cur_shadow_frame_ != nullptr) {
    153     return cur_shadow_frame_->GetDexPC();
    154   } else if (cur_quick_frame_ != nullptr) {
    155     if (IsInInlinedFrame()) {
    156       size_t depth_in_stack_map = current_inlining_depth_ - 1;
    157       const OatQuickMethodHeader* method_header = GetCurrentOatQuickMethodHeader();
    158       CodeInfoEncoding encoding = method_header->GetOptimizedCodeInfo().ExtractEncoding();
    159       return GetCurrentInlineInfo().GetDexPcAtDepth(encoding.inline_info_encoding,
    160                                                     depth_in_stack_map);
    161     } else if (cur_oat_quick_method_header_ == nullptr) {
    162       return DexFile::kDexNoIndex;
    163     } else {
    164       return cur_oat_quick_method_header_->ToDexPc(
    165           GetMethod(), cur_quick_frame_pc_, abort_on_failure);
    166     }
    167   } else {
    168     return 0;
    169   }
    170 }
    171 
    172 extern "C" mirror::Object* artQuickGetProxyThisObject(ArtMethod** sp)
    173     SHARED_REQUIRES(Locks::mutator_lock_);
    174 
    175 mirror::Object* StackVisitor::GetThisObject() const {
    176   DCHECK_EQ(Runtime::Current()->GetClassLinker()->GetImagePointerSize(), sizeof(void*));
    177   ArtMethod* m = GetMethod();
    178   if (m->IsStatic()) {
    179     return nullptr;
    180   } else if (m->IsNative()) {
    181     if (cur_quick_frame_ != nullptr) {
    182       HandleScope* hs = reinterpret_cast<HandleScope*>(
    183           reinterpret_cast<char*>(cur_quick_frame_) + sizeof(ArtMethod*));
    184       return hs->GetReference(0);
    185     } else {
    186       return cur_shadow_frame_->GetVRegReference(0);
    187     }
    188   } else if (m->IsProxyMethod()) {
    189     if (cur_quick_frame_ != nullptr) {
    190       return artQuickGetProxyThisObject(cur_quick_frame_);
    191     } else {
    192       return cur_shadow_frame_->GetVRegReference(0);
    193     }
    194   } else {
    195     const DexFile::CodeItem* code_item = m->GetCodeItem();
    196     if (code_item == nullptr) {
    197       UNIMPLEMENTED(ERROR) << "Failed to determine this object of abstract or proxy method: "
    198           << PrettyMethod(m);
    199       return nullptr;
    200     } else {
    201       uint16_t reg = code_item->registers_size_ - code_item->ins_size_;
    202       uint32_t value = 0;
    203       bool success = GetVReg(m, reg, kReferenceVReg, &value);
    204       // We currently always guarantee the `this` object is live throughout the method.
    205       CHECK(success) << "Failed to read the this object in " << PrettyMethod(m);
    206       return reinterpret_cast<mirror::Object*>(value);
    207     }
    208   }
    209 }
    210 
    211 size_t StackVisitor::GetNativePcOffset() const {
    212   DCHECK(!IsShadowFrame());
    213   return GetCurrentOatQuickMethodHeader()->NativeQuickPcOffset(cur_quick_frame_pc_);
    214 }
    215 
    216 bool StackVisitor::GetVRegFromDebuggerShadowFrame(uint16_t vreg,
    217                                                   VRegKind kind,
    218                                                   uint32_t* val) const {
    219   size_t frame_id = const_cast<StackVisitor*>(this)->GetFrameId();
    220   ShadowFrame* shadow_frame = thread_->FindDebuggerShadowFrame(frame_id);
    221   if (shadow_frame != nullptr) {
    222     bool* updated_vreg_flags = thread_->GetUpdatedVRegFlags(frame_id);
    223     DCHECK(updated_vreg_flags != nullptr);
    224     if (updated_vreg_flags[vreg]) {
    225       // Value is set by the debugger.
    226       if (kind == kReferenceVReg) {
    227         *val = static_cast<uint32_t>(reinterpret_cast<uintptr_t>(
    228             shadow_frame->GetVRegReference(vreg)));
    229       } else {
    230         *val = shadow_frame->GetVReg(vreg);
    231       }
    232       return true;
    233     }
    234   }
    235   // No value is set by the debugger.
    236   return false;
    237 }
    238 
    239 bool StackVisitor::GetVReg(ArtMethod* m, uint16_t vreg, VRegKind kind, uint32_t* val) const {
    240   if (cur_quick_frame_ != nullptr) {
    241     DCHECK(context_ != nullptr);  // You can't reliably read registers without a context.
    242     DCHECK(m == GetMethod());
    243     // Check if there is value set by the debugger.
    244     if (GetVRegFromDebuggerShadowFrame(vreg, kind, val)) {
    245       return true;
    246     }
    247     DCHECK(cur_oat_quick_method_header_->IsOptimized());
    248     return GetVRegFromOptimizedCode(m, vreg, kind, val);
    249   } else {
    250     DCHECK(cur_shadow_frame_ != nullptr);
    251     if (kind == kReferenceVReg) {
    252       *val = static_cast<uint32_t>(reinterpret_cast<uintptr_t>(
    253           cur_shadow_frame_->GetVRegReference(vreg)));
    254     } else {
    255       *val = cur_shadow_frame_->GetVReg(vreg);
    256     }
    257     return true;
    258   }
    259 }
    260 
    261 bool StackVisitor::GetVRegFromOptimizedCode(ArtMethod* m, uint16_t vreg, VRegKind kind,
    262                                             uint32_t* val) const {
    263   DCHECK_EQ(m, GetMethod());
    264   const DexFile::CodeItem* code_item = m->GetCodeItem();
    265   DCHECK(code_item != nullptr) << PrettyMethod(m);  // Can't be null or how would we compile
    266                                                     // its instructions?
    267   uint16_t number_of_dex_registers = code_item->registers_size_;
    268   DCHECK_LT(vreg, code_item->registers_size_);
    269   const OatQuickMethodHeader* method_header = GetCurrentOatQuickMethodHeader();
    270   CodeInfo code_info = method_header->GetOptimizedCodeInfo();
    271   CodeInfoEncoding encoding = code_info.ExtractEncoding();
    272 
    273   uint32_t native_pc_offset = method_header->NativeQuickPcOffset(cur_quick_frame_pc_);
    274   StackMap stack_map = code_info.GetStackMapForNativePcOffset(native_pc_offset, encoding);
    275   DCHECK(stack_map.IsValid());
    276   size_t depth_in_stack_map = current_inlining_depth_ - 1;
    277 
    278   DexRegisterMap dex_register_map = IsInInlinedFrame()
    279       ? code_info.GetDexRegisterMapAtDepth(depth_in_stack_map,
    280                                            code_info.GetInlineInfoOf(stack_map, encoding),
    281                                            encoding,
    282                                            number_of_dex_registers)
    283       : code_info.GetDexRegisterMapOf(stack_map, encoding, number_of_dex_registers);
    284 
    285   if (!dex_register_map.IsValid()) {
    286     return false;
    287   }
    288   DexRegisterLocation::Kind location_kind =
    289       dex_register_map.GetLocationKind(vreg, number_of_dex_registers, code_info, encoding);
    290   switch (location_kind) {
    291     case DexRegisterLocation::Kind::kInStack: {
    292       const int32_t offset = dex_register_map.GetStackOffsetInBytes(vreg,
    293                                                                     number_of_dex_registers,
    294                                                                     code_info,
    295                                                                     encoding);
    296       const uint8_t* addr = reinterpret_cast<const uint8_t*>(cur_quick_frame_) + offset;
    297       *val = *reinterpret_cast<const uint32_t*>(addr);
    298       return true;
    299     }
    300     case DexRegisterLocation::Kind::kInRegister:
    301     case DexRegisterLocation::Kind::kInRegisterHigh:
    302     case DexRegisterLocation::Kind::kInFpuRegister:
    303     case DexRegisterLocation::Kind::kInFpuRegisterHigh: {
    304       uint32_t reg =
    305           dex_register_map.GetMachineRegister(vreg, number_of_dex_registers, code_info, encoding);
    306       return GetRegisterIfAccessible(reg, kind, val);
    307     }
    308     case DexRegisterLocation::Kind::kConstant:
    309       *val = dex_register_map.GetConstant(vreg, number_of_dex_registers, code_info, encoding);
    310       return true;
    311     case DexRegisterLocation::Kind::kNone:
    312       return false;
    313     default:
    314       LOG(FATAL)
    315           << "Unexpected location kind "
    316           << dex_register_map.GetLocationInternalKind(vreg,
    317                                                       number_of_dex_registers,
    318                                                       code_info,
    319                                                       encoding);
    320       UNREACHABLE();
    321   }
    322 }
    323 
    324 bool StackVisitor::GetRegisterIfAccessible(uint32_t reg, VRegKind kind, uint32_t* val) const {
    325   const bool is_float = (kind == kFloatVReg) || (kind == kDoubleLoVReg) || (kind == kDoubleHiVReg);
    326 
    327   // X86 float registers are 64-bit and the logic below does not apply.
    328   DCHECK(!is_float || kRuntimeISA != InstructionSet::kX86);
    329 
    330   if (!IsAccessibleRegister(reg, is_float)) {
    331     return false;
    332   }
    333   uintptr_t ptr_val = GetRegister(reg, is_float);
    334   const bool target64 = Is64BitInstructionSet(kRuntimeISA);
    335   if (target64) {
    336     const bool wide_lo = (kind == kLongLoVReg) || (kind == kDoubleLoVReg);
    337     const bool wide_hi = (kind == kLongHiVReg) || (kind == kDoubleHiVReg);
    338     int64_t value_long = static_cast<int64_t>(ptr_val);
    339     if (wide_lo) {
    340       ptr_val = static_cast<uintptr_t>(Low32Bits(value_long));
    341     } else if (wide_hi) {
    342       ptr_val = static_cast<uintptr_t>(High32Bits(value_long));
    343     }
    344   }
    345   *val = ptr_val;
    346   return true;
    347 }
    348 
    349 bool StackVisitor::GetVRegPairFromDebuggerShadowFrame(uint16_t vreg,
    350                                                       VRegKind kind_lo,
    351                                                       VRegKind kind_hi,
    352                                                       uint64_t* val) const {
    353   uint32_t low_32bits;
    354   uint32_t high_32bits;
    355   bool success = GetVRegFromDebuggerShadowFrame(vreg, kind_lo, &low_32bits);
    356   success &= GetVRegFromDebuggerShadowFrame(vreg + 1, kind_hi, &high_32bits);
    357   if (success) {
    358     *val = (static_cast<uint64_t>(high_32bits) << 32) | static_cast<uint64_t>(low_32bits);
    359   }
    360   return success;
    361 }
    362 
    363 bool StackVisitor::GetVRegPair(ArtMethod* m, uint16_t vreg, VRegKind kind_lo,
    364                                VRegKind kind_hi, uint64_t* val) const {
    365   if (kind_lo == kLongLoVReg) {
    366     DCHECK_EQ(kind_hi, kLongHiVReg);
    367   } else if (kind_lo == kDoubleLoVReg) {
    368     DCHECK_EQ(kind_hi, kDoubleHiVReg);
    369   } else {
    370     LOG(FATAL) << "Expected long or double: kind_lo=" << kind_lo << ", kind_hi=" << kind_hi;
    371     UNREACHABLE();
    372   }
    373   // Check if there is value set by the debugger.
    374   if (GetVRegPairFromDebuggerShadowFrame(vreg, kind_lo, kind_hi, val)) {
    375     return true;
    376   }
    377   if (cur_quick_frame_ != nullptr) {
    378     DCHECK(context_ != nullptr);  // You can't reliably read registers without a context.
    379     DCHECK(m == GetMethod());
    380     DCHECK(cur_oat_quick_method_header_->IsOptimized());
    381     return GetVRegPairFromOptimizedCode(m, vreg, kind_lo, kind_hi, val);
    382   } else {
    383     DCHECK(cur_shadow_frame_ != nullptr);
    384     *val = cur_shadow_frame_->GetVRegLong(vreg);
    385     return true;
    386   }
    387 }
    388 
    389 bool StackVisitor::GetVRegPairFromOptimizedCode(ArtMethod* m, uint16_t vreg,
    390                                                 VRegKind kind_lo, VRegKind kind_hi,
    391                                                 uint64_t* val) const {
    392   uint32_t low_32bits;
    393   uint32_t high_32bits;
    394   bool success = GetVRegFromOptimizedCode(m, vreg, kind_lo, &low_32bits);
    395   success &= GetVRegFromOptimizedCode(m, vreg + 1, kind_hi, &high_32bits);
    396   if (success) {
    397     *val = (static_cast<uint64_t>(high_32bits) << 32) | static_cast<uint64_t>(low_32bits);
    398   }
    399   return success;
    400 }
    401 
    402 bool StackVisitor::GetRegisterPairIfAccessible(uint32_t reg_lo, uint32_t reg_hi,
    403                                                VRegKind kind_lo, uint64_t* val) const {
    404   const bool is_float = (kind_lo == kDoubleLoVReg);
    405   if (!IsAccessibleRegister(reg_lo, is_float) || !IsAccessibleRegister(reg_hi, is_float)) {
    406     return false;
    407   }
    408   uintptr_t ptr_val_lo = GetRegister(reg_lo, is_float);
    409   uintptr_t ptr_val_hi = GetRegister(reg_hi, is_float);
    410   bool target64 = Is64BitInstructionSet(kRuntimeISA);
    411   if (target64) {
    412     int64_t value_long_lo = static_cast<int64_t>(ptr_val_lo);
    413     int64_t value_long_hi = static_cast<int64_t>(ptr_val_hi);
    414     ptr_val_lo = static_cast<uintptr_t>(Low32Bits(value_long_lo));
    415     ptr_val_hi = static_cast<uintptr_t>(High32Bits(value_long_hi));
    416   }
    417   *val = (static_cast<uint64_t>(ptr_val_hi) << 32) | static_cast<uint32_t>(ptr_val_lo);
    418   return true;
    419 }
    420 
    421 bool StackVisitor::SetVReg(ArtMethod* m,
    422                            uint16_t vreg,
    423                            uint32_t new_value,
    424                            VRegKind kind) {
    425   const DexFile::CodeItem* code_item = m->GetCodeItem();
    426   if (code_item == nullptr) {
    427     return false;
    428   }
    429   ShadowFrame* shadow_frame = GetCurrentShadowFrame();
    430   if (shadow_frame == nullptr) {
    431     // This is a compiled frame: we must prepare and update a shadow frame that will
    432     // be executed by the interpreter after deoptimization of the stack.
    433     const size_t frame_id = GetFrameId();
    434     const uint16_t num_regs = code_item->registers_size_;
    435     shadow_frame = thread_->FindOrCreateDebuggerShadowFrame(frame_id, num_regs, m, GetDexPc());
    436     CHECK(shadow_frame != nullptr);
    437     // Remember the vreg has been set for debugging and must not be overwritten by the
    438     // original value during deoptimization of the stack.
    439     thread_->GetUpdatedVRegFlags(frame_id)[vreg] = true;
    440   }
    441   if (kind == kReferenceVReg) {
    442     shadow_frame->SetVRegReference(vreg, reinterpret_cast<mirror::Object*>(new_value));
    443   } else {
    444     shadow_frame->SetVReg(vreg, new_value);
    445   }
    446   return true;
    447 }
    448 
    449 bool StackVisitor::SetVRegPair(ArtMethod* m,
    450                                uint16_t vreg,
    451                                uint64_t new_value,
    452                                VRegKind kind_lo,
    453                                VRegKind kind_hi) {
    454   if (kind_lo == kLongLoVReg) {
    455     DCHECK_EQ(kind_hi, kLongHiVReg);
    456   } else if (kind_lo == kDoubleLoVReg) {
    457     DCHECK_EQ(kind_hi, kDoubleHiVReg);
    458   } else {
    459     LOG(FATAL) << "Expected long or double: kind_lo=" << kind_lo << ", kind_hi=" << kind_hi;
    460     UNREACHABLE();
    461   }
    462   const DexFile::CodeItem* code_item = m->GetCodeItem();
    463   if (code_item == nullptr) {
    464     return false;
    465   }
    466   ShadowFrame* shadow_frame = GetCurrentShadowFrame();
    467   if (shadow_frame == nullptr) {
    468     // This is a compiled frame: we must prepare for deoptimization (see SetVRegFromDebugger).
    469     const size_t frame_id = GetFrameId();
    470     const uint16_t num_regs = code_item->registers_size_;
    471     shadow_frame = thread_->FindOrCreateDebuggerShadowFrame(frame_id, num_regs, m, GetDexPc());
    472     CHECK(shadow_frame != nullptr);
    473     // Remember the vreg pair has been set for debugging and must not be overwritten by the
    474     // original value during deoptimization of the stack.
    475     thread_->GetUpdatedVRegFlags(frame_id)[vreg] = true;
    476     thread_->GetUpdatedVRegFlags(frame_id)[vreg + 1] = true;
    477   }
    478   shadow_frame->SetVRegLong(vreg, new_value);
    479   return true;
    480 }
    481 
    482 bool StackVisitor::IsAccessibleGPR(uint32_t reg) const {
    483   DCHECK(context_ != nullptr);
    484   return context_->IsAccessibleGPR(reg);
    485 }
    486 
    487 uintptr_t* StackVisitor::GetGPRAddress(uint32_t reg) const {
    488   DCHECK(cur_quick_frame_ != nullptr) << "This is a quick frame routine";
    489   DCHECK(context_ != nullptr);
    490   return context_->GetGPRAddress(reg);
    491 }
    492 
    493 uintptr_t StackVisitor::GetGPR(uint32_t reg) const {
    494   DCHECK(cur_quick_frame_ != nullptr) << "This is a quick frame routine";
    495   DCHECK(context_ != nullptr);
    496   return context_->GetGPR(reg);
    497 }
    498 
    499 bool StackVisitor::IsAccessibleFPR(uint32_t reg) const {
    500   DCHECK(context_ != nullptr);
    501   return context_->IsAccessibleFPR(reg);
    502 }
    503 
    504 uintptr_t StackVisitor::GetFPR(uint32_t reg) const {
    505   DCHECK(cur_quick_frame_ != nullptr) << "This is a quick frame routine";
    506   DCHECK(context_ != nullptr);
    507   return context_->GetFPR(reg);
    508 }
    509 
    510 uintptr_t StackVisitor::GetReturnPc() const {
    511   uint8_t* sp = reinterpret_cast<uint8_t*>(GetCurrentQuickFrame());
    512   DCHECK(sp != nullptr);
    513   uint8_t* pc_addr = sp + GetCurrentQuickFrameInfo().GetReturnPcOffset();
    514   return *reinterpret_cast<uintptr_t*>(pc_addr);
    515 }
    516 
    517 void StackVisitor::SetReturnPc(uintptr_t new_ret_pc) {
    518   uint8_t* sp = reinterpret_cast<uint8_t*>(GetCurrentQuickFrame());
    519   CHECK(sp != nullptr);
    520   uint8_t* pc_addr = sp + GetCurrentQuickFrameInfo().GetReturnPcOffset();
    521   *reinterpret_cast<uintptr_t*>(pc_addr) = new_ret_pc;
    522 }
    523 
    524 size_t StackVisitor::ComputeNumFrames(Thread* thread, StackWalkKind walk_kind) {
    525   struct NumFramesVisitor : public StackVisitor {
    526     NumFramesVisitor(Thread* thread_in, StackWalkKind walk_kind_in)
    527         : StackVisitor(thread_in, nullptr, walk_kind_in), frames(0) {}
    528 
    529     bool VisitFrame() OVERRIDE {
    530       frames++;
    531       return true;
    532     }
    533 
    534     size_t frames;
    535   };
    536   NumFramesVisitor visitor(thread, walk_kind);
    537   visitor.WalkStack(true);
    538   return visitor.frames;
    539 }
    540 
    541 bool StackVisitor::GetNextMethodAndDexPc(ArtMethod** next_method, uint32_t* next_dex_pc) {
    542   struct HasMoreFramesVisitor : public StackVisitor {
    543     HasMoreFramesVisitor(Thread* thread,
    544                          StackWalkKind walk_kind,
    545                          size_t num_frames,
    546                          size_t frame_height)
    547         : StackVisitor(thread, nullptr, walk_kind, num_frames),
    548           frame_height_(frame_height),
    549           found_frame_(false),
    550           has_more_frames_(false),
    551           next_method_(nullptr),
    552           next_dex_pc_(0) {
    553     }
    554 
    555     bool VisitFrame() OVERRIDE SHARED_REQUIRES(Locks::mutator_lock_) {
    556       if (found_frame_) {
    557         ArtMethod* method = GetMethod();
    558         if (method != nullptr && !method->IsRuntimeMethod()) {
    559           has_more_frames_ = true;
    560           next_method_ = method;
    561           next_dex_pc_ = GetDexPc();
    562           return false;  // End stack walk once next method is found.
    563         }
    564       } else if (GetFrameHeight() == frame_height_) {
    565         found_frame_ = true;
    566       }
    567       return true;
    568     }
    569 
    570     size_t frame_height_;
    571     bool found_frame_;
    572     bool has_more_frames_;
    573     ArtMethod* next_method_;
    574     uint32_t next_dex_pc_;
    575   };
    576   HasMoreFramesVisitor visitor(thread_, walk_kind_, GetNumFrames(), GetFrameHeight());
    577   visitor.WalkStack(true);
    578   *next_method = visitor.next_method_;
    579   *next_dex_pc = visitor.next_dex_pc_;
    580   return visitor.has_more_frames_;
    581 }
    582 
    583 void StackVisitor::DescribeStack(Thread* thread) {
    584   struct DescribeStackVisitor : public StackVisitor {
    585     explicit DescribeStackVisitor(Thread* thread_in)
    586         : StackVisitor(thread_in, nullptr, StackVisitor::StackWalkKind::kIncludeInlinedFrames) {}
    587 
    588     bool VisitFrame() OVERRIDE SHARED_REQUIRES(Locks::mutator_lock_) {
    589       LOG(INFO) << "Frame Id=" << GetFrameId() << " " << DescribeLocation();
    590       return true;
    591     }
    592   };
    593   DescribeStackVisitor visitor(thread);
    594   visitor.WalkStack(true);
    595 }
    596 
    597 std::string StackVisitor::DescribeLocation() const {
    598   std::string result("Visiting method '");
    599   ArtMethod* m = GetMethod();
    600   if (m == nullptr) {
    601     return "upcall";
    602   }
    603   result += PrettyMethod(m);
    604   result += StringPrintf("' at dex PC 0x%04x", GetDexPc());
    605   if (!IsShadowFrame()) {
    606     result += StringPrintf(" (native PC %p)", reinterpret_cast<void*>(GetCurrentQuickFramePc()));
    607   }
    608   return result;
    609 }
    610 
    611 static instrumentation::InstrumentationStackFrame& GetInstrumentationStackFrame(Thread* thread,
    612                                                                                 uint32_t depth) {
    613   CHECK_LT(depth, thread->GetInstrumentationStack()->size());
    614   return thread->GetInstrumentationStack()->at(depth);
    615 }
    616 
    617 static void AssertPcIsWithinQuickCode(ArtMethod* method, uintptr_t pc)
    618     SHARED_REQUIRES(Locks::mutator_lock_) {
    619   if (method->IsNative() || method->IsRuntimeMethod() || method->IsProxyMethod()) {
    620     return;
    621   }
    622 
    623   if (pc == reinterpret_cast<uintptr_t>(GetQuickInstrumentationExitPc())) {
    624     return;
    625   }
    626 
    627   const void* code = method->GetEntryPointFromQuickCompiledCode();
    628   if (code == GetQuickInstrumentationEntryPoint()) {
    629     return;
    630   }
    631 
    632   ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
    633   if (class_linker->IsQuickToInterpreterBridge(code) ||
    634       class_linker->IsQuickResolutionStub(code)) {
    635     return;
    636   }
    637 
    638   // If we are the JIT then we may have just compiled the method after the
    639   // IsQuickToInterpreterBridge check.
    640   Runtime* runtime = Runtime::Current();
    641   if (runtime->UseJitCompilation() && runtime->GetJit()->GetCodeCache()->ContainsPc(code)) {
    642     return;
    643   }
    644 
    645   uint32_t code_size = OatQuickMethodHeader::FromEntryPoint(code)->code_size_;
    646   uintptr_t code_start = reinterpret_cast<uintptr_t>(code);
    647   CHECK(code_start <= pc && pc <= (code_start + code_size))
    648       << PrettyMethod(method)
    649       << " pc=" << std::hex << pc
    650       << " code_start=" << code_start
    651       << " code_size=" << code_size;
    652 }
    653 
    654 void StackVisitor::SanityCheckFrame() const {
    655   if (kIsDebugBuild) {
    656     ArtMethod* method = GetMethod();
    657     auto* declaring_class = method->GetDeclaringClass();
    658     // Runtime methods have null declaring class.
    659     if (!method->IsRuntimeMethod()) {
    660       CHECK(declaring_class != nullptr);
    661       CHECK_EQ(declaring_class->GetClass(), declaring_class->GetClass()->GetClass())
    662           << declaring_class;
    663     } else {
    664       CHECK(declaring_class == nullptr);
    665     }
    666     Runtime* const runtime = Runtime::Current();
    667     LinearAlloc* const linear_alloc = runtime->GetLinearAlloc();
    668     if (!linear_alloc->Contains(method)) {
    669       // Check class linker linear allocs.
    670       mirror::Class* klass = method->GetDeclaringClass();
    671       LinearAlloc* const class_linear_alloc = (klass != nullptr)
    672           ? runtime->GetClassLinker()->GetAllocatorForClassLoader(klass->GetClassLoader())
    673           : linear_alloc;
    674       if (!class_linear_alloc->Contains(method)) {
    675         // Check image space.
    676         bool in_image = false;
    677         for (auto& space : runtime->GetHeap()->GetContinuousSpaces()) {
    678           if (space->IsImageSpace()) {
    679             auto* image_space = space->AsImageSpace();
    680             const auto& header = image_space->GetImageHeader();
    681             const ImageSection& methods = header.GetMethodsSection();
    682             const ImageSection& runtime_methods = header.GetRuntimeMethodsSection();
    683             const size_t offset =  reinterpret_cast<const uint8_t*>(method) - image_space->Begin();
    684             if (methods.Contains(offset) || runtime_methods.Contains(offset)) {
    685               in_image = true;
    686               break;
    687             }
    688           }
    689         }
    690         CHECK(in_image) << PrettyMethod(method) << " not in linear alloc or image";
    691       }
    692     }
    693     if (cur_quick_frame_ != nullptr) {
    694       AssertPcIsWithinQuickCode(method, cur_quick_frame_pc_);
    695       // Frame sanity.
    696       size_t frame_size = GetCurrentQuickFrameInfo().FrameSizeInBytes();
    697       CHECK_NE(frame_size, 0u);
    698       // A rough guess at an upper size we expect to see for a frame.
    699       // 256 registers
    700       // 2 words HandleScope overhead
    701       // 3+3 register spills
    702       // TODO: this seems architecture specific for the case of JNI frames.
    703       // TODO: 083-compiler-regressions ManyFloatArgs shows this estimate is wrong.
    704       // const size_t kMaxExpectedFrameSize = (256 + 2 + 3 + 3) * sizeof(word);
    705       const size_t kMaxExpectedFrameSize = 2 * KB;
    706       CHECK_LE(frame_size, kMaxExpectedFrameSize) << PrettyMethod(method);
    707       size_t return_pc_offset = GetCurrentQuickFrameInfo().GetReturnPcOffset();
    708       CHECK_LT(return_pc_offset, frame_size);
    709     }
    710   }
    711 }
    712 
    713 // Counts the number of references in the parameter list of the corresponding method.
    714 // Note: Thus does _not_ include "this" for non-static methods.
    715 static uint32_t GetNumberOfReferenceArgsWithoutReceiver(ArtMethod* method)
    716     SHARED_REQUIRES(Locks::mutator_lock_) {
    717   uint32_t shorty_len;
    718   const char* shorty = method->GetShorty(&shorty_len);
    719   uint32_t refs = 0;
    720   for (uint32_t i = 1; i < shorty_len ; ++i) {
    721     if (shorty[i] == 'L') {
    722       refs++;
    723     }
    724   }
    725   return refs;
    726 }
    727 
    728 QuickMethodFrameInfo StackVisitor::GetCurrentQuickFrameInfo() const {
    729   if (cur_oat_quick_method_header_ != nullptr) {
    730     return cur_oat_quick_method_header_->GetFrameInfo();
    731   }
    732 
    733   ArtMethod* method = GetMethod();
    734   Runtime* runtime = Runtime::Current();
    735 
    736   if (method->IsAbstract()) {
    737     return runtime->GetCalleeSaveMethodFrameInfo(Runtime::kRefsAndArgs);
    738   }
    739 
    740   // This goes before IsProxyMethod since runtime methods have a null declaring class.
    741   if (method->IsRuntimeMethod()) {
    742     return runtime->GetRuntimeMethodFrameInfo(method);
    743   }
    744 
    745   if (method->IsProxyMethod()) {
    746     // There is only one direct method of a proxy class: the constructor. A direct method is
    747     // cloned from the original java.lang.reflect.Proxy and is executed as usual quick
    748     // compiled method without any stubs. Therefore the method must have a OatQuickMethodHeader.
    749     DCHECK(!method->IsDirect() && !method->IsConstructor())
    750         << "Constructors of proxy classes must have a OatQuickMethodHeader";
    751     return runtime->GetCalleeSaveMethodFrameInfo(Runtime::kRefsAndArgs);
    752   }
    753 
    754   // The only remaining case is if the method is native and uses the generic JNI stub.
    755   DCHECK(method->IsNative());
    756   ClassLinker* class_linker = runtime->GetClassLinker();
    757   const void* entry_point = runtime->GetInstrumentation()->GetQuickCodeFor(method, sizeof(void*));
    758   DCHECK(class_linker->IsQuickGenericJniStub(entry_point)) << PrettyMethod(method);
    759   // Generic JNI frame.
    760   uint32_t handle_refs = GetNumberOfReferenceArgsWithoutReceiver(method) + 1;
    761   size_t scope_size = HandleScope::SizeOf(handle_refs);
    762   QuickMethodFrameInfo callee_info = runtime->GetCalleeSaveMethodFrameInfo(Runtime::kRefsAndArgs);
    763 
    764   // Callee saves + handle scope + method ref + alignment
    765   // Note: -sizeof(void*) since callee-save frame stores a whole method pointer.
    766   size_t frame_size = RoundUp(
    767       callee_info.FrameSizeInBytes() - sizeof(void*) + sizeof(ArtMethod*) + scope_size,
    768       kStackAlignment);
    769   return QuickMethodFrameInfo(frame_size, callee_info.CoreSpillMask(), callee_info.FpSpillMask());
    770 }
    771 
    772 void StackVisitor::WalkStack(bool include_transitions) {
    773   DCHECK(thread_ == Thread::Current() || thread_->IsSuspended());
    774   CHECK_EQ(cur_depth_, 0U);
    775   bool exit_stubs_installed = Runtime::Current()->GetInstrumentation()->AreExitStubsInstalled();
    776   uint32_t instrumentation_stack_depth = 0;
    777   size_t inlined_frames_count = 0;
    778 
    779   for (const ManagedStack* current_fragment = thread_->GetManagedStack();
    780        current_fragment != nullptr; current_fragment = current_fragment->GetLink()) {
    781     cur_shadow_frame_ = current_fragment->GetTopShadowFrame();
    782     cur_quick_frame_ = current_fragment->GetTopQuickFrame();
    783     cur_quick_frame_pc_ = 0;
    784     cur_oat_quick_method_header_ = nullptr;
    785 
    786     if (cur_quick_frame_ != nullptr) {  // Handle quick stack frames.
    787       // Can't be both a shadow and a quick fragment.
    788       DCHECK(current_fragment->GetTopShadowFrame() == nullptr);
    789       ArtMethod* method = *cur_quick_frame_;
    790       while (method != nullptr) {
    791         cur_oat_quick_method_header_ = method->GetOatQuickMethodHeader(cur_quick_frame_pc_);
    792         SanityCheckFrame();
    793 
    794         if ((walk_kind_ == StackWalkKind::kIncludeInlinedFrames ||
    795              walk_kind_ == StackWalkKind::kIncludeInlinedFramesNoResolve)
    796             && (cur_oat_quick_method_header_ != nullptr)
    797             && cur_oat_quick_method_header_->IsOptimized()) {
    798           CodeInfo code_info = cur_oat_quick_method_header_->GetOptimizedCodeInfo();
    799           CodeInfoEncoding encoding = code_info.ExtractEncoding();
    800           uint32_t native_pc_offset =
    801               cur_oat_quick_method_header_->NativeQuickPcOffset(cur_quick_frame_pc_);
    802           StackMap stack_map = code_info.GetStackMapForNativePcOffset(native_pc_offset, encoding);
    803           if (stack_map.IsValid() && stack_map.HasInlineInfo(encoding.stack_map_encoding)) {
    804             InlineInfo inline_info = code_info.GetInlineInfoOf(stack_map, encoding);
    805             DCHECK_EQ(current_inlining_depth_, 0u);
    806             for (current_inlining_depth_ = inline_info.GetDepth(encoding.inline_info_encoding);
    807                  current_inlining_depth_ != 0;
    808                  --current_inlining_depth_) {
    809               bool should_continue = VisitFrame();
    810               if (UNLIKELY(!should_continue)) {
    811                 return;
    812               }
    813               cur_depth_++;
    814               inlined_frames_count++;
    815             }
    816           }
    817         }
    818 
    819         bool should_continue = VisitFrame();
    820         if (UNLIKELY(!should_continue)) {
    821           return;
    822         }
    823 
    824         QuickMethodFrameInfo frame_info = GetCurrentQuickFrameInfo();
    825         if (context_ != nullptr) {
    826           context_->FillCalleeSaves(reinterpret_cast<uint8_t*>(cur_quick_frame_), frame_info);
    827         }
    828         // Compute PC for next stack frame from return PC.
    829         size_t frame_size = frame_info.FrameSizeInBytes();
    830         size_t return_pc_offset = frame_size - sizeof(void*);
    831         uint8_t* return_pc_addr = reinterpret_cast<uint8_t*>(cur_quick_frame_) + return_pc_offset;
    832         uintptr_t return_pc = *reinterpret_cast<uintptr_t*>(return_pc_addr);
    833 
    834         if (UNLIKELY(exit_stubs_installed)) {
    835           // While profiling, the return pc is restored from the side stack, except when walking
    836           // the stack for an exception where the side stack will be unwound in VisitFrame.
    837           if (reinterpret_cast<uintptr_t>(GetQuickInstrumentationExitPc()) == return_pc) {
    838             const instrumentation::InstrumentationStackFrame& instrumentation_frame =
    839                 GetInstrumentationStackFrame(thread_, instrumentation_stack_depth);
    840             instrumentation_stack_depth++;
    841             if (GetMethod() == Runtime::Current()->GetCalleeSaveMethod(Runtime::kSaveAll)) {
    842               // Skip runtime save all callee frames which are used to deliver exceptions.
    843             } else if (instrumentation_frame.interpreter_entry_) {
    844               ArtMethod* callee = Runtime::Current()->GetCalleeSaveMethod(Runtime::kRefsAndArgs);
    845               CHECK_EQ(GetMethod(), callee) << "Expected: " << PrettyMethod(callee) << " Found: "
    846                                             << PrettyMethod(GetMethod());
    847             } else {
    848               CHECK_EQ(instrumentation_frame.method_, GetMethod())
    849                   << "Expected: " << PrettyMethod(instrumentation_frame.method_)
    850                   << " Found: " << PrettyMethod(GetMethod());
    851             }
    852             if (num_frames_ != 0) {
    853               // Check agreement of frame Ids only if num_frames_ is computed to avoid infinite
    854               // recursion.
    855               size_t frame_id = instrumentation::Instrumentation::ComputeFrameId(
    856                   thread_,
    857                   cur_depth_,
    858                   inlined_frames_count);
    859               CHECK_EQ(instrumentation_frame.frame_id_, frame_id);
    860             }
    861             return_pc = instrumentation_frame.return_pc_;
    862           }
    863         }
    864 
    865         cur_quick_frame_pc_ = return_pc;
    866         uint8_t* next_frame = reinterpret_cast<uint8_t*>(cur_quick_frame_) + frame_size;
    867         cur_quick_frame_ = reinterpret_cast<ArtMethod**>(next_frame);
    868 
    869         if (kDebugStackWalk) {
    870           LOG(INFO) << PrettyMethod(method) << "@" << method << " size=" << frame_size
    871               << std::boolalpha
    872               << " optimized=" << (cur_oat_quick_method_header_ != nullptr &&
    873                                    cur_oat_quick_method_header_->IsOptimized())
    874               << " native=" << method->IsNative()
    875               << std::noboolalpha
    876               << " entrypoints=" << method->GetEntryPointFromQuickCompiledCode()
    877               << "," << method->GetEntryPointFromJni()
    878               << " next=" << *cur_quick_frame_;
    879         }
    880 
    881         cur_depth_++;
    882         method = *cur_quick_frame_;
    883       }
    884     } else if (cur_shadow_frame_ != nullptr) {
    885       do {
    886         SanityCheckFrame();
    887         bool should_continue = VisitFrame();
    888         if (UNLIKELY(!should_continue)) {
    889           return;
    890         }
    891         cur_depth_++;
    892         cur_shadow_frame_ = cur_shadow_frame_->GetLink();
    893       } while (cur_shadow_frame_ != nullptr);
    894     }
    895     if (include_transitions) {
    896       bool should_continue = VisitFrame();
    897       if (!should_continue) {
    898         return;
    899       }
    900     }
    901     cur_depth_++;
    902   }
    903   if (num_frames_ != 0) {
    904     CHECK_EQ(cur_depth_, num_frames_);
    905   }
    906 }
    907 
    908 void JavaFrameRootInfo::Describe(std::ostream& os) const {
    909   const StackVisitor* visitor = stack_visitor_;
    910   CHECK(visitor != nullptr);
    911   os << "Type=" << GetType() << " thread_id=" << GetThreadId() << " location=" <<
    912       visitor->DescribeLocation() << " vreg=" << vreg_;
    913 }
    914 
    915 int StackVisitor::GetVRegOffsetFromQuickCode(const DexFile::CodeItem* code_item,
    916                                              uint32_t core_spills, uint32_t fp_spills,
    917                                              size_t frame_size, int reg, InstructionSet isa) {
    918   size_t pointer_size = InstructionSetPointerSize(isa);
    919   if (kIsDebugBuild) {
    920     auto* runtime = Runtime::Current();
    921     if (runtime != nullptr) {
    922       CHECK_EQ(runtime->GetClassLinker()->GetImagePointerSize(), pointer_size);
    923     }
    924   }
    925   DCHECK_ALIGNED(frame_size, kStackAlignment);
    926   DCHECK_NE(reg, -1);
    927   int spill_size = POPCOUNT(core_spills) * GetBytesPerGprSpillLocation(isa)
    928       + POPCOUNT(fp_spills) * GetBytesPerFprSpillLocation(isa)
    929       + sizeof(uint32_t);  // Filler.
    930   int num_regs = code_item->registers_size_ - code_item->ins_size_;
    931   int temp_threshold = code_item->registers_size_;
    932   const int max_num_special_temps = 1;
    933   if (reg == temp_threshold) {
    934     // The current method pointer corresponds to special location on stack.
    935     return 0;
    936   } else if (reg >= temp_threshold + max_num_special_temps) {
    937     /*
    938      * Special temporaries may have custom locations and the logic above deals with that.
    939      * However, non-special temporaries are placed relative to the outs.
    940      */
    941     int temps_start = code_item->outs_size_ * sizeof(uint32_t) + pointer_size /* art method */;
    942     int relative_offset = (reg - (temp_threshold + max_num_special_temps)) * sizeof(uint32_t);
    943     return temps_start + relative_offset;
    944   }  else if (reg < num_regs) {
    945     int locals_start = frame_size - spill_size - num_regs * sizeof(uint32_t);
    946     return locals_start + (reg * sizeof(uint32_t));
    947   } else {
    948     // Handle ins.
    949     return frame_size + ((reg - num_regs) * sizeof(uint32_t)) + pointer_size /* art method */;
    950   }
    951 }
    952 
    953 void LockCountData::AddMonitor(Thread* self, mirror::Object* obj) {
    954   if (obj == nullptr) {
    955     return;
    956   }
    957 
    958   // If there's an error during enter, we won't have locked the monitor. So check there's no
    959   // exception.
    960   if (self->IsExceptionPending()) {
    961     return;
    962   }
    963 
    964   if (monitors_ == nullptr) {
    965     monitors_.reset(new std::vector<mirror::Object*>());
    966   }
    967   monitors_->push_back(obj);
    968 }
    969 
    970 void LockCountData::RemoveMonitorOrThrow(Thread* self, const mirror::Object* obj) {
    971   if (obj == nullptr) {
    972     return;
    973   }
    974   bool found_object = false;
    975   if (monitors_ != nullptr) {
    976     // We need to remove one pointer to ref, as duplicates are used for counting recursive locks.
    977     // We arbitrarily choose the first one.
    978     auto it = std::find(monitors_->begin(), monitors_->end(), obj);
    979     if (it != monitors_->end()) {
    980       monitors_->erase(it);
    981       found_object = true;
    982     }
    983   }
    984   if (!found_object) {
    985     // The object wasn't found. Time for an IllegalMonitorStateException.
    986     // The order here isn't fully clear. Assume that any other pending exception is swallowed.
    987     // TODO: Maybe make already pending exception a suppressed exception.
    988     self->ClearException();
    989     self->ThrowNewExceptionF("Ljava/lang/IllegalMonitorStateException;",
    990                              "did not lock monitor on object of type '%s' before unlocking",
    991                              PrettyTypeOf(const_cast<mirror::Object*>(obj)).c_str());
    992   }
    993 }
    994 
    995 // Helper to unlock a monitor. Must be NO_THREAD_SAFETY_ANALYSIS, as we can't statically show
    996 // that the object was locked.
    997 void MonitorExitHelper(Thread* self, mirror::Object* obj) NO_THREAD_SAFETY_ANALYSIS {
    998   DCHECK(self != nullptr);
    999   DCHECK(obj != nullptr);
   1000   obj->MonitorExit(self);
   1001 }
   1002 
   1003 bool LockCountData::CheckAllMonitorsReleasedOrThrow(Thread* self) {
   1004   DCHECK(self != nullptr);
   1005   if (monitors_ != nullptr) {
   1006     if (!monitors_->empty()) {
   1007       // There may be an exception pending, if the method is terminating abruptly. Clear it.
   1008       // TODO: Should we add this as a suppressed exception?
   1009       self->ClearException();
   1010 
   1011       // OK, there are monitors that are still locked. To enforce structured locking (and avoid
   1012       // deadlocks) we unlock all of them before we raise the IllegalMonitorState exception.
   1013       for (mirror::Object* obj : *monitors_) {
   1014         MonitorExitHelper(self, obj);
   1015         // If this raised an exception, ignore. TODO: Should we add this as suppressed
   1016         // exceptions?
   1017         if (self->IsExceptionPending()) {
   1018           self->ClearException();
   1019         }
   1020       }
   1021       // Raise an exception, just give the first object as the sample.
   1022       mirror::Object* first = (*monitors_)[0];
   1023       self->ThrowNewExceptionF("Ljava/lang/IllegalMonitorStateException;",
   1024                                "did not unlock monitor on object of type '%s'",
   1025                                PrettyTypeOf(first).c_str());
   1026 
   1027       // To make sure this path is not triggered again, clean out the monitors.
   1028       monitors_->clear();
   1029 
   1030       return false;
   1031     }
   1032   }
   1033   return true;
   1034 }
   1035 
   1036 }  // namespace art
   1037