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/*
* 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