stack.cc revision 7940e44f4517de5e2634a7e07d58d0fb26160513 
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 "oat/runtime/context.h"
20#include "mirror/abstract_method-inl.h"
21#include "mirror/class-inl.h"
22#include "mirror/object.h"
23#include "mirror/object-inl.h"
24#include "mirror/object_array-inl.h"
25#include "object_utils.h"
26#include "thread_list.h"
27#include "throw_location.h"
28
29namespace art {
30
31mirror::Object* ShadowFrame::GetThisObject() const {
32  mirror::AbstractMethod* m = GetMethod();
33  if (m->IsStatic()) {
34    return NULL;
35  } else if (m->IsNative()) {
36    return GetVRegReference(0);
37  } else {
38    const DexFile::CodeItem* code_item = MethodHelper(m).GetCodeItem();
39    CHECK(code_item != NULL) << PrettyMethod(m);
40    uint16_t reg = code_item->registers_size_ - code_item->ins_size_;
41    return GetVRegReference(reg);
42  }
43}
44
45mirror::Object* ShadowFrame::GetThisObject(uint16_t num_ins) const {
46  mirror::AbstractMethod* m = GetMethod();
47  if (m->IsStatic()) {
48    return NULL;
49  } else {
50    return GetVRegReference(NumberOfVRegs() - num_ins);
51  }
52}
53
54ThrowLocation ShadowFrame::GetCurrentLocationForThrow() const {
55  return ThrowLocation(GetThisObject(), GetMethod(), GetDexPC());
56}
57
58size_t ManagedStack::NumJniShadowFrameReferences() const {
59  size_t count = 0;
60  for (const ManagedStack* current_fragment = this; current_fragment != NULL;
61       current_fragment = current_fragment->GetLink()) {
62    for (ShadowFrame* current_frame = current_fragment->top_shadow_frame_; current_frame != NULL;
63         current_frame = current_frame->GetLink()) {
64      if (current_frame->GetMethod()->IsNative()) {
65        // The JNI ShadowFrame only contains references. (For indirect reference.)
66        count += current_frame->NumberOfVRegs();
67      }
68    }
69  }
70  return count;
71}
72
73bool ManagedStack::ShadowFramesContain(mirror::Object** shadow_frame_entry) const {
74  for (const ManagedStack* current_fragment = this; current_fragment != NULL;
75       current_fragment = current_fragment->GetLink()) {
76    for (ShadowFrame* current_frame = current_fragment->top_shadow_frame_; current_frame != NULL;
77         current_frame = current_frame->GetLink()) {
78      if (current_frame->Contains(shadow_frame_entry)) {
79        return true;
80      }
81    }
82  }
83  return false;
84}
85
86StackVisitor::StackVisitor(Thread* thread, Context* context)
87    : thread_(thread), cur_shadow_frame_(NULL),
88      cur_quick_frame_(NULL), cur_quick_frame_pc_(0), num_frames_(0), cur_depth_(0),
89      context_(context) {
90  DCHECK(thread == Thread::Current() || thread->IsSuspended()) << *thread;
91}
92
93uint32_t StackVisitor::GetDexPc() const {
94  if (cur_shadow_frame_ != NULL) {
95    return cur_shadow_frame_->GetDexPC();
96  } else if (cur_quick_frame_ != NULL) {
97    return GetMethod()->ToDexPc(cur_quick_frame_pc_);
98  } else {
99    return 0;
100  }
101}
102
103mirror::Object* StackVisitor::GetThisObject() const {
104  mirror::AbstractMethod* m = GetMethod();
105  if (m->IsStatic()) {
106    return NULL;
107  } else if (m->IsNative()) {
108    if (cur_quick_frame_ != NULL) {
109      StackIndirectReferenceTable* sirt =
110          reinterpret_cast<StackIndirectReferenceTable*>(
111              reinterpret_cast<char*>(cur_quick_frame_) +
112              m->GetSirtOffsetInBytes());
113      return sirt->GetReference(0);
114    } else {
115      return cur_shadow_frame_->GetVRegReference(0);
116    }
117  } else {
118    const DexFile::CodeItem* code_item = MethodHelper(m).GetCodeItem();
119    if (code_item == NULL) {
120      UNIMPLEMENTED(ERROR) << "Failed to determine this object of abstract or proxy method"
121          << PrettyMethod(m);
122      return NULL;
123    } else {
124      uint16_t reg = code_item->registers_size_ - code_item->ins_size_;
125      return reinterpret_cast<mirror::Object*>(GetVReg(m, reg, kReferenceVReg));
126    }
127  }
128}
129
130size_t StackVisitor::GetNativePcOffset() const {
131  DCHECK(!IsShadowFrame());
132  return GetMethod()->NativePcOffset(cur_quick_frame_pc_);
133}
134
135uint32_t StackVisitor::GetVReg(mirror::AbstractMethod* m, uint16_t vreg, VRegKind kind) const {
136  if (cur_quick_frame_ != NULL) {
137    DCHECK(context_ != NULL); // You can't reliably read registers without a context.
138    DCHECK(m == GetMethod());
139    const VmapTable vmap_table(m->GetVmapTableRaw());
140    uint32_t vmap_offset;
141    // TODO: IsInContext stops before spotting floating point registers.
142    if (vmap_table.IsInContext(vreg, vmap_offset, kind)) {
143      bool is_float = (kind == kFloatVReg) || (kind == kDoubleLoVReg) || (kind == kDoubleHiVReg);
144      uint32_t spill_mask = is_float ? m->GetFpSpillMask()
145                                     : m->GetCoreSpillMask();
146      return GetGPR(vmap_table.ComputeRegister(spill_mask, vmap_offset, kind));
147    } else {
148      const DexFile::CodeItem* code_item = MethodHelper(m).GetCodeItem();
149      DCHECK(code_item != NULL) << PrettyMethod(m); // Can't be NULL or how would we compile its instructions?
150      size_t frame_size = m->GetFrameSizeInBytes();
151      return GetVReg(cur_quick_frame_, code_item, m->GetCoreSpillMask(), m->GetFpSpillMask(),
152                     frame_size, vreg);
153    }
154  } else {
155    return cur_shadow_frame_->GetVReg(vreg);
156  }
157}
158
159void StackVisitor::SetVReg(mirror::AbstractMethod* m, uint16_t vreg, uint32_t new_value,
160                           VRegKind kind) {
161  if (cur_quick_frame_ != NULL) {
162    DCHECK(context_ != NULL); // You can't reliably write registers without a context.
163    DCHECK(m == GetMethod());
164    const VmapTable vmap_table(m->GetVmapTableRaw());
165    uint32_t vmap_offset;
166    // TODO: IsInContext stops before spotting floating point registers.
167    if (vmap_table.IsInContext(vreg, vmap_offset, kind)) {
168      bool is_float = (kind == kFloatVReg) || (kind == kDoubleLoVReg) || (kind == kDoubleHiVReg);
169      uint32_t spill_mask = is_float ? m->GetFpSpillMask() : m->GetCoreSpillMask();
170      const uint32_t reg = vmap_table.ComputeRegister(spill_mask, vmap_offset, kReferenceVReg);
171      SetGPR(reg, new_value);
172    } else {
173      const DexFile::CodeItem* code_item = MethodHelper(m).GetCodeItem();
174      DCHECK(code_item != NULL) << PrettyMethod(m); // Can't be NULL or how would we compile its instructions?
175      uint32_t core_spills = m->GetCoreSpillMask();
176      uint32_t fp_spills = m->GetFpSpillMask();
177      size_t frame_size = m->GetFrameSizeInBytes();
178      int offset = GetVRegOffset(code_item, core_spills, fp_spills, frame_size, vreg);
179      byte* vreg_addr = reinterpret_cast<byte*>(GetCurrentQuickFrame()) + offset;
180      *reinterpret_cast<uint32_t*>(vreg_addr) = new_value;
181    }
182  } else {
183    return cur_shadow_frame_->SetVReg(vreg, new_value);
184  }
185}
186
187uintptr_t StackVisitor::GetGPR(uint32_t reg) const {
188  DCHECK (cur_quick_frame_ != NULL) << "This is a quick frame routine";
189  return context_->GetGPR(reg);
190}
191
192void StackVisitor::SetGPR(uint32_t reg, uintptr_t value) {
193  DCHECK (cur_quick_frame_ != NULL) << "This is a quick frame routine";
194  context_->SetGPR(reg, value);
195}
196
197uintptr_t StackVisitor::GetReturnPc() const {
198  mirror::AbstractMethod** sp = GetCurrentQuickFrame();
199  DCHECK(sp != NULL);
200  byte* pc_addr = reinterpret_cast<byte*>(sp) + GetMethod()->GetReturnPcOffsetInBytes();
201  return *reinterpret_cast<uintptr_t*>(pc_addr);
202}
203
204void StackVisitor::SetReturnPc(uintptr_t new_ret_pc) {
205  mirror::AbstractMethod** sp = GetCurrentQuickFrame();
206  CHECK(sp != NULL);
207  byte* pc_addr = reinterpret_cast<byte*>(sp) + GetMethod()->GetReturnPcOffsetInBytes();
208  *reinterpret_cast<uintptr_t*>(pc_addr) = new_ret_pc;
209}
210
211size_t StackVisitor::ComputeNumFrames(Thread* thread) {
212  struct NumFramesVisitor : public StackVisitor {
213    explicit NumFramesVisitor(Thread* thread)
214        : StackVisitor(thread, NULL), frames(0) {}
215
216    virtual bool VisitFrame() {
217      frames++;
218      return true;
219    }
220
221    size_t frames;
222  };
223  NumFramesVisitor visitor(thread);
224  visitor.WalkStack(true);
225  return visitor.frames;
226}
227
228void StackVisitor::DescribeStack(Thread* thread) {
229  struct DescribeStackVisitor : public StackVisitor {
230    explicit DescribeStackVisitor(Thread* thread)
231        : StackVisitor(thread, NULL) {}
232
233    virtual bool VisitFrame() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
234      LOG(INFO) << "Frame Id=" << GetFrameId() << " " << DescribeLocation();
235      return true;
236    }
237  };
238  DescribeStackVisitor visitor(thread);
239  visitor.WalkStack(true);
240}
241
242std::string StackVisitor::DescribeLocation() const {
243  std::string result("Visiting method '");
244  mirror::AbstractMethod* m = GetMethod();
245  if (m == NULL) {
246    return "upcall";
247  }
248  result += PrettyMethod(m);
249  result += StringPrintf("' at dex PC 0x%04zx", GetDexPc());
250  if (!IsShadowFrame()) {
251    result += StringPrintf(" (native PC %p)", reinterpret_cast<void*>(GetCurrentQuickFramePc()));
252  }
253  return result;
254}
255
256instrumentation::InstrumentationStackFrame StackVisitor::GetInstrumentationStackFrame(uint32_t depth) const {
257  return thread_->GetInstrumentationStack()->at(depth);
258}
259
260void StackVisitor::SanityCheckFrame() const {
261#ifndef NDEBUG
262  mirror::AbstractMethod* method = GetMethod();
263  CHECK(method->GetClass() == mirror::AbstractMethod::GetMethodClass() ||
264        method->GetClass() == mirror::AbstractMethod::GetConstructorClass());
265  if (cur_quick_frame_ != NULL) {
266    method->AssertPcIsWithinCode(cur_quick_frame_pc_);
267    // Frame sanity.
268    size_t frame_size = method->GetFrameSizeInBytes();
269    CHECK_NE(frame_size, 0u);
270    CHECK_LT(frame_size, 1024u);
271    size_t return_pc_offset = method->GetReturnPcOffsetInBytes();
272    CHECK_LT(return_pc_offset, frame_size);
273  }
274#endif
275}
276
277void StackVisitor::WalkStack(bool include_transitions) {
278  DCHECK(thread_ == Thread::Current() || thread_->IsSuspended());
279  CHECK_EQ(cur_depth_, 0U);
280  bool exit_stubs_installed = Runtime::Current()->GetInstrumentation()->AreExitStubsInstalled();
281  uint32_t instrumentation_stack_depth = 0;
282  for (const ManagedStack* current_fragment = thread_->GetManagedStack(); current_fragment != NULL;
283       current_fragment = current_fragment->GetLink()) {
284    cur_shadow_frame_ = current_fragment->GetTopShadowFrame();
285    cur_quick_frame_ = current_fragment->GetTopQuickFrame();
286    cur_quick_frame_pc_ = current_fragment->GetTopQuickFramePc();
287    if (cur_quick_frame_ != NULL) {  // Handle quick stack frames.
288      // Can't be both a shadow and a quick fragment.
289      DCHECK(current_fragment->GetTopShadowFrame() == NULL);
290      mirror::AbstractMethod* method = *cur_quick_frame_;
291      while (method != NULL) {
292        DCHECK(cur_quick_frame_pc_ != GetInstrumentationExitPc());
293        SanityCheckFrame();
294        bool should_continue = VisitFrame();
295        if (UNLIKELY(!should_continue)) {
296          return;
297        }
298        if (context_ != NULL) {
299          context_->FillCalleeSaves(*this);
300        }
301        size_t frame_size = method->GetFrameSizeInBytes();
302        // Compute PC for next stack frame from return PC.
303        size_t return_pc_offset = method->GetReturnPcOffsetInBytes();
304        byte* return_pc_addr = reinterpret_cast<byte*>(cur_quick_frame_) + return_pc_offset;
305        uintptr_t return_pc = *reinterpret_cast<uintptr_t*>(return_pc_addr);
306        if (UNLIKELY(exit_stubs_installed)) {
307          // While profiling, the return pc is restored from the side stack, except when walking
308          // the stack for an exception where the side stack will be unwound in VisitFrame.
309          if (GetInstrumentationExitPc() == return_pc) {
310            instrumentation::InstrumentationStackFrame instrumentation_frame =
311                GetInstrumentationStackFrame(instrumentation_stack_depth);
312            instrumentation_stack_depth++;
313            if (instrumentation_frame.interpreter_entry_) {
314              mirror::AbstractMethod* callee = Runtime::Current()->GetCalleeSaveMethod(Runtime::kRefsAndArgs);
315              if (GetMethod() != callee) {
316                LOG(FATAL) << "Expected: " << callee << " Found: " << PrettyMethod(GetMethod());
317              }
318            } else if (instrumentation_frame.method_ != GetMethod()) {
319              LOG(FATAL)  << "Expected: " << PrettyMethod(instrumentation_frame.method_)
320                << " Found: " << PrettyMethod(GetMethod());
321            }
322            if (num_frames_ != 0) {
323              // Check agreement of frame Ids only if num_frames_ is computed to avoid infinite
324              // recursion.
325              CHECK(instrumentation_frame.frame_id_ == GetFrameId())
326                    << "Expected: " << instrumentation_frame.frame_id_
327                    << " Found: " << GetFrameId();
328            }
329            return_pc = instrumentation_frame.return_pc_;
330          }
331        }
332        cur_quick_frame_pc_ = return_pc;
333        byte* next_frame = reinterpret_cast<byte*>(cur_quick_frame_) + frame_size;
334        cur_quick_frame_ = reinterpret_cast<mirror::AbstractMethod**>(next_frame);
335        cur_depth_++;
336        method = *cur_quick_frame_;
337      }
338    } else if (cur_shadow_frame_ != NULL) {
339      do {
340        SanityCheckFrame();
341        bool should_continue = VisitFrame();
342        if (UNLIKELY(!should_continue)) {
343          return;
344        }
345        cur_depth_++;
346        cur_shadow_frame_ = cur_shadow_frame_->GetLink();
347      } while(cur_shadow_frame_ != NULL);
348    }
349    if (include_transitions) {
350      bool should_continue = VisitFrame();
351      if (!should_continue) {
352        return;
353      }
354    }
355    cur_depth_++;
356  }
357  if (num_frames_ != 0) {
358    CHECK_EQ(cur_depth_, num_frames_);
359  }
360}
361
362}  // namespace art
363