src/stack.cc - platform/art - Gitiles

 /*
  * Copyright (C) 2011 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include "stack.h"

 #include "compiler.h"
 #include "oat/runtime/context.h"
 #include "object.h"
 #include "object_utils.h"
 #include "thread_list.h"

 namespace art {

 void ManagedStack::PushManagedStackFragment(ManagedStack* fragment) {
   // Copy this top fragment into given fragment.
   memcpy(fragment, this, sizeof(ManagedStack));
   // Clear this fragment, which has become the top.
   memset(this, 0, sizeof(ManagedStack));
   // Link our top fragment onto the given fragment.
   link_ = fragment;
 }

 void ManagedStack::PopManagedStackFragment(const ManagedStack& fragment) {
   DCHECK(&fragment == link_);
   // Copy this given fragment back to the top.
   memcpy(this, &fragment, sizeof(ManagedStack));
 }

 size_t ManagedStack::NumShadowFrameReferences() const {
   size_t count = 0;
   for (const ManagedStack* current_fragment = this; current_fragment != NULL;
        current_fragment = current_fragment->GetLink()) {
     for (ShadowFrame* current_frame = current_fragment->top_shadow_frame_; current_frame != NULL;
          current_frame = current_frame->GetLink()) {
       count += current_frame->NumberOfReferences();
     }
   }
   return count;
 }

 bool ManagedStack::ShadowFramesContain(Object** shadow_frame_entry) const {
   for (const ManagedStack* current_fragment = this; current_fragment != NULL;
        current_fragment = current_fragment->GetLink()) {
     for (ShadowFrame* current_frame = current_fragment->top_shadow_frame_; current_frame != NULL;
          current_frame = current_frame->GetLink()) {
       if (current_frame->Contains(shadow_frame_entry)) {
         return true;
       }
     }
   }
   return false;
 }

 uint32_t StackVisitor::GetDexPc() const {
   if (cur_shadow_frame_ != NULL) {
     return cur_shadow_frame_->GetDexPC();
   } else if (cur_quick_frame_ != NULL) {
     return GetMethod()->ToDexPC(AdjustQuickFramePcForDexPcComputation(cur_quick_frame_pc_));
   } else {
     return 0;
   }
 }

 uint32_t StackVisitor::GetVReg(Method* m, int vreg) const {
   if (cur_quick_frame_ != NULL) {
     DCHECK(context_ != NULL); // You can't reliably read registers without a context.
     DCHECK(m == GetMethod());
     uint32_t core_spills = m->GetCoreSpillMask();
     const VmapTable vmap_table(m->GetVmapTableRaw());
     uint32_t vmap_offset;
     // TODO: IsInContext stops before spotting floating point registers.
     if (vmap_table.IsInContext(vreg, vmap_offset)) {
       // Compute the register we need to load from the context.
       uint32_t spill_mask = core_spills;
       CHECK_LT(vmap_offset, static_cast<uint32_t>(__builtin_popcount(spill_mask)));
       uint32_t matches = 0;
       uint32_t spill_shifts = 0;
       while (matches != (vmap_offset + 1)) {
         DCHECK_NE(spill_mask, 0u);
         matches += spill_mask & 1;  // Add 1 if the low bit is set.
         spill_mask >>= 1;
         spill_shifts++;
       }
       spill_shifts--;  // Wind back one as we want the last match.
       return GetGPR(spill_shifts);
     } else {
       const DexFile::CodeItem* code_item = MethodHelper(m).GetCodeItem();
       DCHECK(code_item != NULL) << PrettyMethod(m); // Can't be NULL or how would we compile its instructions?
       uint32_t fp_spills = m->GetFpSpillMask();
       size_t frame_size = m->GetFrameSizeInBytes();
       return GetVReg(cur_quick_frame_, code_item, core_spills, fp_spills, frame_size, vreg);
     }
   } else {
     LOG(FATAL) << "Unimplemented - shadow frame GetVReg";
     return 0;  // Keep GCC happy.
   }
 }

 void StackVisitor::SetVReg(Method* m, int vreg, uint32_t new_value) {
   if (cur_quick_frame_ != NULL) {
     DCHECK(context_ != NULL); // You can't reliably write registers without a context.
     DCHECK(m == GetMethod());
     const VmapTable vmap_table(m->GetVmapTableRaw());
     uint32_t vmap_offset;
     // TODO: IsInContext stops before spotting floating point registers.
     if (vmap_table.IsInContext(vreg, vmap_offset)) {
       UNIMPLEMENTED(FATAL);
     }
     const DexFile::CodeItem* code_item = MethodHelper(m).GetCodeItem();
     DCHECK(code_item != NULL) << PrettyMethod(m); // Can't be NULL or how would we compile its instructions?
     uint32_t core_spills = m->GetCoreSpillMask();
     uint32_t fp_spills = m->GetFpSpillMask();
     size_t frame_size = m->GetFrameSizeInBytes();
     int offset = GetVRegOffset(code_item, core_spills, fp_spills, frame_size, vreg);
     byte* vreg_addr = reinterpret_cast<byte*>(GetCurrentQuickFrame()) + offset;
     *reinterpret_cast<uint32_t*>(vreg_addr) = new_value;
   } else {
     LOG(FATAL) << "Unimplemented - shadow frame SetVReg";
   }
 }

 uintptr_t StackVisitor::GetGPR(uint32_t reg) const {
   DCHECK (cur_quick_frame_ != NULL) << "This is a quick frame routine";
   return context_->GetGPR(reg);
 }

 uintptr_t StackVisitor::GetReturnPc() const {
   Method** sp = GetCurrentQuickFrame();
   CHECK(sp != NULL);
   byte* pc_addr = reinterpret_cast<byte*>(sp) + GetMethod()->GetReturnPcOffsetInBytes();
   return *reinterpret_cast<uintptr_t*>(pc_addr);
 }

 void StackVisitor::SetReturnPc(uintptr_t new_ret_pc) {
   Method** sp = GetCurrentQuickFrame();
   CHECK(sp != NULL);
   byte* pc_addr = reinterpret_cast<byte*>(sp) + GetMethod()->GetReturnPcOffsetInBytes();
   *reinterpret_cast<uintptr_t*>(pc_addr) = new_ret_pc;
 }

 size_t StackVisitor::ComputeNumFrames() const {
   struct NumFramesVisitor : public StackVisitor {
     explicit NumFramesVisitor(const ManagedStack* stack,
                               const std::vector<TraceStackFrame>* trace_stack)
         : StackVisitor(stack, trace_stack, NULL), frames(0) {}

     virtual bool VisitFrame() {
       frames++;
       return true;
     }

     size_t frames;
   };

   NumFramesVisitor visitor(stack_start_, trace_stack_);
   visitor.WalkStack(true);
   return visitor.frames;
 }

 void StackVisitor::SanityCheckFrame() const {
 #ifndef NDEBUG
   Method* method = GetMethod();
   CHECK(method->GetClass() == Method::GetMethodClass() ||
         method->GetClass() == Method::GetConstructorClass());
   if (cur_quick_frame_ != NULL) {
     method->AssertPcIsWithinCode(AdjustQuickFramePcForDexPcComputation(cur_quick_frame_pc_));
     // Frame sanity.
     size_t frame_size = method->GetFrameSizeInBytes();
     CHECK_NE(frame_size, 0u);
     CHECK_LT(frame_size, 1024u);
     size_t return_pc_offset = method->GetReturnPcOffsetInBytes();
     CHECK_LT(return_pc_offset, frame_size);
   }
 #endif
 }

 void StackVisitor::WalkStack(bool include_transitions) {
   bool method_tracing_active = Runtime::Current()->IsMethodTracingActive();
   uint32_t trace_stack_depth = 0;
   for (const ManagedStack* current_fragment = stack_start_; current_fragment != NULL;
        current_fragment = current_fragment->GetLink()) {
     cur_shadow_frame_ = current_fragment->GetTopShadowFrame();
     cur_quick_frame_ = current_fragment->GetTopQuickFrame();
     cur_quick_frame_pc_ = current_fragment->GetTopQuickFramePc();
     if (cur_quick_frame_ != NULL) {  // Handle quick stack frames.
       // Can't be both a shadow and a quick fragment.
       DCHECK(current_fragment->GetTopShadowFrame() == NULL);
       Method* method = *cur_quick_frame_;
       do {
         SanityCheckFrame();
         bool should_continue = VisitFrame();
         if (UNLIKELY(!should_continue)) {
           return;
         }
         if (context_ != NULL) {
           context_->FillCalleeSaves(*this);
         }
         size_t frame_size = method->GetFrameSizeInBytes();
         // Compute PC for next stack frame from return PC.
         size_t return_pc_offset = method->GetReturnPcOffsetInBytes();
         byte* return_pc_addr = reinterpret_cast<byte*>(cur_quick_frame_) + return_pc_offset;
         uintptr_t return_pc = *reinterpret_cast<uintptr_t*>(return_pc_addr);
         if (UNLIKELY(method_tracing_active)) {
           // While profiling, the return pc is restored from the side stack, except when walking
           // the stack for an exception where the side stack will be unwound in VisitFrame.
           // TODO: stop using include_transitions as a proxy for is this the catch block visitor.
           if (IsTraceExitPc(return_pc) && !include_transitions) {
             // TODO: unify trace and managed stack.
             TraceStackFrame trace_frame = GetTraceStackFrame(trace_stack_depth);
             trace_stack_depth++;
             CHECK(trace_frame.method_ == GetMethod()) << "Excepted: " << PrettyMethod(method)
                 << " Found: " << PrettyMethod(GetMethod());
             return_pc = trace_frame.return_pc_;
           }
         }
         cur_quick_frame_pc_ = return_pc;
         byte* next_frame = reinterpret_cast<byte*>(cur_quick_frame_) + frame_size;
         cur_quick_frame_ = reinterpret_cast<Method**>(next_frame);
         cur_depth_++;
         method = *cur_quick_frame_;
       } while (method != NULL);
     } else if (cur_shadow_frame_ != NULL) {
       do {
         SanityCheckFrame();
         bool should_continue = VisitFrame();
         if (UNLIKELY(!should_continue)) {
           return;
         }
         cur_depth_++;
         cur_shadow_frame_ = cur_shadow_frame_->GetLink();
       } while(cur_shadow_frame_ != NULL);
     }
     cur_depth_++;
     if (include_transitions) {
       bool should_continue = VisitFrame();
       if (!should_continue) {
         return;
       }
     }
   }
 }

 }  // namespace art
	/*
	* Copyright (C) 2011 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include "stack.h"

	#include "compiler.h"
	#include "oat/runtime/context.h"
	#include "object.h"
	#include "object_utils.h"
	#include "thread_list.h"

	namespace art {

	void ManagedStack::PushManagedStackFragment(ManagedStack* fragment) {
	// Copy this top fragment into given fragment.
	memcpy(fragment, this, sizeof(ManagedStack));
	// Clear this fragment, which has become the top.
	memset(this, 0, sizeof(ManagedStack));
	// Link our top fragment onto the given fragment.
	link_ = fragment;
	}

	void ManagedStack::PopManagedStackFragment(const ManagedStack& fragment) {
	DCHECK(&fragment == link_);
	// Copy this given fragment back to the top.
	memcpy(this, &fragment, sizeof(ManagedStack));
	}

	size_t ManagedStack::NumShadowFrameReferences() const {
	size_t count = 0;
	for (const ManagedStack* current_fragment = this; current_fragment != NULL;
	current_fragment = current_fragment->GetLink()) {
	for (ShadowFrame* current_frame = current_fragment->top_shadow_frame_; current_frame != NULL;
	current_frame = current_frame->GetLink()) {
	count += current_frame->NumberOfReferences();
	}
	}
	return count;
	}

	bool ManagedStack::ShadowFramesContain(Object** shadow_frame_entry) const {
	for (const ManagedStack* current_fragment = this; current_fragment != NULL;
	current_fragment = current_fragment->GetLink()) {
	for (ShadowFrame* current_frame = current_fragment->top_shadow_frame_; current_frame != NULL;
	current_frame = current_frame->GetLink()) {
	if (current_frame->Contains(shadow_frame_entry)) {
	return true;
	}
	}
	}
	return false;
	}

	uint32_t StackVisitor::GetDexPc() const {
	if (cur_shadow_frame_ != NULL) {
	return cur_shadow_frame_->GetDexPC();
	} else if (cur_quick_frame_ != NULL) {
	return GetMethod()->ToDexPC(AdjustQuickFramePcForDexPcComputation(cur_quick_frame_pc_));
	} else {
	return 0;
	}
	}

	uint32_t StackVisitor::GetVReg(Method* m, int vreg) const {
	if (cur_quick_frame_ != NULL) {
	DCHECK(context_ != NULL); // You can't reliably read registers without a context.
	DCHECK(m == GetMethod());
	uint32_t core_spills = m->GetCoreSpillMask();
	const VmapTable vmap_table(m->GetVmapTableRaw());
	uint32_t vmap_offset;
	// TODO: IsInContext stops before spotting floating point registers.
	if (vmap_table.IsInContext(vreg, vmap_offset)) {
	// Compute the register we need to load from the context.
	uint32_t spill_mask = core_spills;
	CHECK_LT(vmap_offset, static_cast<uint32_t>(__builtin_popcount(spill_mask)));
	uint32_t matches = 0;
	uint32_t spill_shifts = 0;
	while (matches != (vmap_offset + 1)) {
	DCHECK_NE(spill_mask, 0u);
	matches += spill_mask & 1; // Add 1 if the low bit is set.
	spill_mask >>= 1;
	spill_shifts++;
	}
	spill_shifts--; // Wind back one as we want the last match.
	return GetGPR(spill_shifts);
	} else {
	const DexFile::CodeItem* code_item = MethodHelper(m).GetCodeItem();
	DCHECK(code_item != NULL) << PrettyMethod(m); // Can't be NULL or how would we compile its instructions?
	uint32_t fp_spills = m->GetFpSpillMask();
	size_t frame_size = m->GetFrameSizeInBytes();
	return GetVReg(cur_quick_frame_, code_item, core_spills, fp_spills, frame_size, vreg);
	}
	} else {
	LOG(FATAL) << "Unimplemented - shadow frame GetVReg";
	return 0; // Keep GCC happy.
	}
	}

	void StackVisitor::SetVReg(Method* m, int vreg, uint32_t new_value) {
	if (cur_quick_frame_ != NULL) {
	DCHECK(context_ != NULL); // You can't reliably write registers without a context.
	DCHECK(m == GetMethod());
	const VmapTable vmap_table(m->GetVmapTableRaw());
	uint32_t vmap_offset;
	// TODO: IsInContext stops before spotting floating point registers.
	if (vmap_table.IsInContext(vreg, vmap_offset)) {
	UNIMPLEMENTED(FATAL);
	}
	const DexFile::CodeItem* code_item = MethodHelper(m).GetCodeItem();
	DCHECK(code_item != NULL) << PrettyMethod(m); // Can't be NULL or how would we compile its instructions?
	uint32_t core_spills = m->GetCoreSpillMask();
	uint32_t fp_spills = m->GetFpSpillMask();
	size_t frame_size = m->GetFrameSizeInBytes();
	int offset = GetVRegOffset(code_item, core_spills, fp_spills, frame_size, vreg);
	byte* vreg_addr = reinterpret_cast<byte*>(GetCurrentQuickFrame()) + offset;
	reinterpret_cast<uint32_t>(vreg_addr) = new_value;
	} else {
	LOG(FATAL) << "Unimplemented - shadow frame SetVReg";
	}
	}

	uintptr_t StackVisitor::GetGPR(uint32_t reg) const {
	DCHECK (cur_quick_frame_ != NULL) << "This is a quick frame routine";
	return context_->GetGPR(reg);
	}

	uintptr_t StackVisitor::GetReturnPc() const {
	Method** sp = GetCurrentQuickFrame();
	CHECK(sp != NULL);
	byte* pc_addr = reinterpret_cast<byte*>(sp) + GetMethod()->GetReturnPcOffsetInBytes();
	return reinterpret_cast<uintptr_t>(pc_addr);
	}

	void StackVisitor::SetReturnPc(uintptr_t new_ret_pc) {
	Method** sp = GetCurrentQuickFrame();
	CHECK(sp != NULL);
	byte* pc_addr = reinterpret_cast<byte*>(sp) + GetMethod()->GetReturnPcOffsetInBytes();
	reinterpret_cast<uintptr_t>(pc_addr) = new_ret_pc;
	}

	size_t StackVisitor::ComputeNumFrames() const {
	struct NumFramesVisitor : public StackVisitor {
	explicit NumFramesVisitor(const ManagedStack* stack,
	const std::vector<TraceStackFrame>* trace_stack)
	: StackVisitor(stack, trace_stack, NULL), frames(0) {}

	virtual bool VisitFrame() {
	frames++;
	return true;
	}

	size_t frames;
	};

	NumFramesVisitor visitor(stack_start_, trace_stack_);
	visitor.WalkStack(true);
	return visitor.frames;
	}

	void StackVisitor::SanityCheckFrame() const {
	#ifndef NDEBUG
	Method* method = GetMethod();
	CHECK(method->GetClass() == Method::GetMethodClass() \|\|
	method->GetClass() == Method::GetConstructorClass());
	if (cur_quick_frame_ != NULL) {
	method->AssertPcIsWithinCode(AdjustQuickFramePcForDexPcComputation(cur_quick_frame_pc_));
	// Frame sanity.
	size_t frame_size = method->GetFrameSizeInBytes();
	CHECK_NE(frame_size, 0u);
	CHECK_LT(frame_size, 1024u);
	size_t return_pc_offset = method->GetReturnPcOffsetInBytes();
	CHECK_LT(return_pc_offset, frame_size);
	}
	#endif
	}

	void StackVisitor::WalkStack(bool include_transitions) {
	bool method_tracing_active = Runtime::Current()->IsMethodTracingActive();
	uint32_t trace_stack_depth = 0;
	for (const ManagedStack* current_fragment = stack_start_; current_fragment != NULL;
	current_fragment = current_fragment->GetLink()) {
	cur_shadow_frame_ = current_fragment->GetTopShadowFrame();
	cur_quick_frame_ = current_fragment->GetTopQuickFrame();
	cur_quick_frame_pc_ = current_fragment->GetTopQuickFramePc();
	if (cur_quick_frame_ != NULL) { // Handle quick stack frames.
	// Can't be both a shadow and a quick fragment.
	DCHECK(current_fragment->GetTopShadowFrame() == NULL);
	Method* method = *cur_quick_frame_;
	do {
	SanityCheckFrame();
	bool should_continue = VisitFrame();
	if (UNLIKELY(!should_continue)) {
	return;
	}
	if (context_ != NULL) {
	context_->FillCalleeSaves(*this);
	}
	size_t frame_size = method->GetFrameSizeInBytes();
	// Compute PC for next stack frame from return PC.
	size_t return_pc_offset = method->GetReturnPcOffsetInBytes();
	byte* return_pc_addr = reinterpret_cast<byte*>(cur_quick_frame_) + return_pc_offset;
	uintptr_t return_pc = reinterpret_cast<uintptr_t>(return_pc_addr);
	if (UNLIKELY(method_tracing_active)) {
	// While profiling, the return pc is restored from the side stack, except when walking
	// the stack for an exception where the side stack will be unwound in VisitFrame.
	// TODO: stop using include_transitions as a proxy for is this the catch block visitor.
	if (IsTraceExitPc(return_pc) && !include_transitions) {
	// TODO: unify trace and managed stack.
	TraceStackFrame trace_frame = GetTraceStackFrame(trace_stack_depth);
	trace_stack_depth++;
	CHECK(trace_frame.method_ == GetMethod()) << "Excepted: " << PrettyMethod(method)
	<< " Found: " << PrettyMethod(GetMethod());
	return_pc = trace_frame.return_pc_;
	}
	}
	cur_quick_frame_pc_ = return_pc;
	byte* next_frame = reinterpret_cast<byte*>(cur_quick_frame_) + frame_size;
	cur_quick_frame_ = reinterpret_cast<Method**>(next_frame);
	cur_depth_++;
	method = *cur_quick_frame_;
	} while (method != NULL);
	} else if (cur_shadow_frame_ != NULL) {
	do {
	SanityCheckFrame();
	bool should_continue = VisitFrame();
	if (UNLIKELY(!should_continue)) {
	return;
	}
	cur_depth_++;
	cur_shadow_frame_ = cur_shadow_frame_->GetLink();
	} while(cur_shadow_frame_ != NULL);
	}
	cur_depth_++;
	if (include_transitions) {
	bool should_continue = VisitFrame();
	if (!should_continue) {
	return;
	}
	}
	}
	}

	} // namespace art