90 lines
3.4 KiB
C++
90 lines
3.4 KiB
C++
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// Copyright 2019 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "base/profiler/chrome_unwinder_android.h"
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#include "base/numerics/checked_math.h"
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#include "base/profiler/module_cache.h"
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#include "base/profiler/native_unwinder.h"
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#include "build/build_config.h"
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namespace base {
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ChromeUnwinderAndroid::ChromeUnwinderAndroid(
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const ArmCFITable* cfi_table,
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const ModuleCache::Module* chrome_module)
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: cfi_table_(cfi_table), chrome_module_(chrome_module) {
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DCHECK(cfi_table_);
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DCHECK(chrome_module_);
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}
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ChromeUnwinderAndroid::~ChromeUnwinderAndroid() = default;
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bool ChromeUnwinderAndroid::CanUnwindFrom(const Frame& current_frame) const {
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return current_frame.module == chrome_module_;
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}
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UnwindResult ChromeUnwinderAndroid::TryUnwind(RegisterContext* thread_context,
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uintptr_t stack_top,
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ModuleCache* module_cache,
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std::vector<Frame>* stack) const {
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DCHECK(CanUnwindFrom(stack->back()));
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do {
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const ModuleCache::Module* module = stack->back().module;
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uintptr_t pc = RegisterContextInstructionPointer(thread_context);
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DCHECK_GE(pc, module->GetBaseAddress());
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uintptr_t func_addr = pc - module->GetBaseAddress();
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auto entry = cfi_table_->FindEntryForAddress(func_addr);
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if (!entry)
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return UnwindResult::ABORTED;
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if (!Step(thread_context, stack_top, *entry))
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return UnwindResult::ABORTED;
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stack->emplace_back(RegisterContextInstructionPointer(thread_context),
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module_cache->GetModuleForAddress(
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RegisterContextInstructionPointer(thread_context)));
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} while (CanUnwindFrom(stack->back()));
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return UnwindResult::UNRECOGNIZED_FRAME;
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}
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// static
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bool ChromeUnwinderAndroid::Step(RegisterContext* thread_context,
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uintptr_t stack_top,
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const ArmCFITable::FrameEntry& entry) {
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CHECK_NE(RegisterContextStackPointer(thread_context), 0U);
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CHECK_LE(RegisterContextStackPointer(thread_context), stack_top);
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if (entry.cfa_offset == 0) {
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uintptr_t pc = RegisterContextInstructionPointer(thread_context);
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uintptr_t return_address = static_cast<uintptr_t>(thread_context->arm_lr);
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if (pc == return_address)
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return false;
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RegisterContextInstructionPointer(thread_context) = return_address;
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} else {
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// The rules for unwinding using the CFI information are:
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// SP_prev = SP_cur + cfa_offset and
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// PC_prev = * (SP_prev - ra_offset).
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auto new_sp =
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CheckedNumeric<uintptr_t>(RegisterContextStackPointer(thread_context)) +
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CheckedNumeric<uint16_t>(entry.cfa_offset);
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if (!new_sp.AssignIfValid(&RegisterContextStackPointer(thread_context)) ||
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RegisterContextStackPointer(thread_context) >= stack_top) {
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return false;
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}
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if (entry.ra_offset > entry.cfa_offset)
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return false;
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// Underflow is prevented because |ra_offset| <= |cfa_offset|.
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uintptr_t ip_address = (new_sp - CheckedNumeric<uint16_t>(entry.ra_offset))
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.ValueOrDie<uintptr_t>();
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RegisterContextInstructionPointer(thread_context) =
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*reinterpret_cast<uintptr_t*>(ip_address);
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}
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return true;
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}
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} // namespace base
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