556 lines
17 KiB
C++
556 lines
17 KiB
C++
/*
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* Copyright (C) 2017 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <stdint.h>
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#include <unwindstack/DwarfLocation.h>
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#include <unwindstack/DwarfMemory.h>
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#include <unwindstack/DwarfSection.h>
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#include <unwindstack/DwarfStructs.h>
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#include <unwindstack/Log.h>
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#include <unwindstack/Memory.h>
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#include <unwindstack/Regs.h>
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#include "DwarfCfa.h"
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#include "DwarfEncoding.h"
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#include "DwarfError.h"
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#include "DwarfOp.h"
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namespace unwindstack {
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DwarfSection::DwarfSection(Memory* memory) : memory_(memory), last_error_(DWARF_ERROR_NONE) {}
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const DwarfFde* DwarfSection::GetFdeFromPc(uint64_t pc) {
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uint64_t fde_offset;
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if (!GetFdeOffsetFromPc(pc, &fde_offset)) {
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return nullptr;
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}
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const DwarfFde* fde = GetFdeFromOffset(fde_offset);
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// Guaranteed pc >= pc_start, need to check pc in the fde range.
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if (pc < fde->pc_end) {
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return fde;
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}
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last_error_ = DWARF_ERROR_ILLEGAL_STATE;
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return nullptr;
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}
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bool DwarfSection::Step(uint64_t pc, Regs* regs, Memory* process_memory) {
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last_error_ = DWARF_ERROR_NONE;
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const DwarfFde* fde = GetFdeFromPc(pc);
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if (fde == nullptr || fde->cie == nullptr) {
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last_error_ = DWARF_ERROR_ILLEGAL_STATE;
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return false;
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}
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// Now get the location information for this pc.
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dwarf_loc_regs_t loc_regs;
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if (!GetCfaLocationInfo(pc, fde, &loc_regs)) {
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return false;
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}
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// Now eval the actual registers.
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return Eval(fde->cie, process_memory, loc_regs, regs);
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}
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template <typename AddressType>
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bool DwarfSectionImpl<AddressType>::EvalExpression(const DwarfLocation& loc, uint8_t version,
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Memory* regular_memory, AddressType* value) {
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DwarfOp<AddressType> op(&memory_, regular_memory);
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// Need to evaluate the op data.
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uint64_t start = loc.values[1];
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uint64_t end = start + loc.values[0];
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if (!op.Eval(start, end, version)) {
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last_error_ = op.last_error();
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return false;
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}
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if (op.StackSize() == 0) {
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last_error_ = DWARF_ERROR_ILLEGAL_STATE;
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return false;
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}
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// We don't support an expression that evaluates to a register number.
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if (op.is_register()) {
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last_error_ = DWARF_ERROR_NOT_IMPLEMENTED;
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return false;
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}
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*value = op.StackAt(0);
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return true;
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}
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template <typename AddressType>
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bool DwarfSectionImpl<AddressType>::Eval(const DwarfCie* cie, Memory* regular_memory,
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const dwarf_loc_regs_t& loc_regs, Regs* regs) {
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RegsImpl<AddressType>* cur_regs = reinterpret_cast<RegsImpl<AddressType>*>(regs);
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if (cie->return_address_register >= cur_regs->total_regs()) {
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last_error_ = DWARF_ERROR_ILLEGAL_VALUE;
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return false;
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}
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// Get the cfa value;
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auto cfa_entry = loc_regs.find(CFA_REG);
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if (cfa_entry == loc_regs.end()) {
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last_error_ = DWARF_ERROR_CFA_NOT_DEFINED;
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return false;
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}
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AddressType prev_pc = regs->pc();
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AddressType prev_cfa = regs->sp();
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AddressType cfa;
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const DwarfLocation* loc = &cfa_entry->second;
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// Only a few location types are valid for the cfa.
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switch (loc->type) {
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case DWARF_LOCATION_REGISTER:
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if (loc->values[0] >= cur_regs->total_regs()) {
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last_error_ = DWARF_ERROR_ILLEGAL_VALUE;
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return false;
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}
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// If the stack pointer register is the CFA, and the stack
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// pointer register does not have any associated location
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// information, use the current cfa value.
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if (regs->sp_reg() == loc->values[0] && loc_regs.count(regs->sp_reg()) == 0) {
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cfa = prev_cfa;
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} else {
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cfa = (*cur_regs)[loc->values[0]];
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}
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cfa += loc->values[1];
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break;
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case DWARF_LOCATION_EXPRESSION:
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case DWARF_LOCATION_VAL_EXPRESSION: {
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AddressType value;
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if (!EvalExpression(*loc, cie->version, regular_memory, &value)) {
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return false;
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}
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if (loc->type == DWARF_LOCATION_EXPRESSION) {
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if (!regular_memory->Read(value, &cfa, sizeof(AddressType))) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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} else {
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cfa = value;
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}
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break;
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}
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default:
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last_error_ = DWARF_ERROR_ILLEGAL_VALUE;
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return false;
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}
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// This code is not guaranteed to work in cases where a register location
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// is a double indirection to the actual value. For example, if r3 is set
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// to r5 + 4, and r5 is set to CFA + 4, then this won't necessarily work
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// because it does not guarantee that r5 is evaluated before r3.
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// Check that this case does not exist, and error if it does.
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bool return_address_undefined = false;
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for (const auto& entry : loc_regs) {
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uint16_t reg = entry.first;
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// Already handled the CFA register.
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if (reg == CFA_REG) continue;
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if (reg >= cur_regs->total_regs()) {
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// Skip this unknown register.
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continue;
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}
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const DwarfLocation* loc = &entry.second;
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switch (loc->type) {
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case DWARF_LOCATION_OFFSET:
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if (!regular_memory->Read(cfa + loc->values[0], &(*cur_regs)[reg], sizeof(AddressType))) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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break;
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case DWARF_LOCATION_VAL_OFFSET:
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(*cur_regs)[reg] = cfa + loc->values[0];
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break;
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case DWARF_LOCATION_REGISTER: {
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uint16_t cur_reg = loc->values[0];
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if (cur_reg >= cur_regs->total_regs()) {
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last_error_ = DWARF_ERROR_ILLEGAL_VALUE;
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return false;
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}
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if (loc_regs.find(cur_reg) != loc_regs.end()) {
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// This is a double indirection, a register definition references
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// another register which is also defined as something other
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// than a register.
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log(0,
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"Invalid indirection: register %d references register %d which is "
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"not a plain register.\n",
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reg, cur_reg);
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last_error_ = DWARF_ERROR_ILLEGAL_STATE;
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return false;
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}
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(*cur_regs)[reg] = (*cur_regs)[cur_reg] + loc->values[1];
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break;
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}
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case DWARF_LOCATION_EXPRESSION:
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case DWARF_LOCATION_VAL_EXPRESSION: {
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AddressType value;
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if (!EvalExpression(*loc, cie->version, regular_memory, &value)) {
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return false;
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}
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if (loc->type == DWARF_LOCATION_EXPRESSION) {
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if (!regular_memory->Read(value, &(*cur_regs)[reg], sizeof(AddressType))) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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} else {
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(*cur_regs)[reg] = value;
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}
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break;
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}
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case DWARF_LOCATION_UNDEFINED:
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if (reg == cie->return_address_register) {
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return_address_undefined = true;
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}
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default:
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break;
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}
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}
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// Find the return address location.
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if (return_address_undefined) {
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cur_regs->set_pc(0);
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} else {
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cur_regs->set_pc((*cur_regs)[cie->return_address_register]);
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}
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cur_regs->set_sp(cfa);
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// Stop if the cfa and pc are the same.
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return prev_cfa != cfa || prev_pc != cur_regs->pc();
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}
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template <typename AddressType>
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const DwarfCie* DwarfSectionImpl<AddressType>::GetCie(uint64_t offset) {
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auto cie_entry = cie_entries_.find(offset);
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if (cie_entry != cie_entries_.end()) {
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return &cie_entry->second;
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}
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DwarfCie* cie = &cie_entries_[offset];
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memory_.set_cur_offset(offset);
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if (!FillInCie(cie)) {
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// Erase the cached entry.
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cie_entries_.erase(offset);
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return nullptr;
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}
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return cie;
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}
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template <typename AddressType>
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bool DwarfSectionImpl<AddressType>::FillInCie(DwarfCie* cie) {
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uint32_t length32;
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if (!memory_.ReadBytes(&length32, sizeof(length32))) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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// Set the default for the lsda encoding.
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cie->lsda_encoding = DW_EH_PE_omit;
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if (length32 == static_cast<uint32_t>(-1)) {
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// 64 bit Cie
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uint64_t length64;
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if (!memory_.ReadBytes(&length64, sizeof(length64))) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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cie->cfa_instructions_end = memory_.cur_offset() + length64;
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cie->fde_address_encoding = DW_EH_PE_sdata8;
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uint64_t cie_id;
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if (!memory_.ReadBytes(&cie_id, sizeof(cie_id))) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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if (!IsCie64(cie_id)) {
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// This is not a Cie, something has gone horribly wrong.
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last_error_ = DWARF_ERROR_ILLEGAL_VALUE;
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return false;
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}
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} else {
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// 32 bit Cie
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cie->cfa_instructions_end = memory_.cur_offset() + length32;
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cie->fde_address_encoding = DW_EH_PE_sdata4;
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uint32_t cie_id;
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if (!memory_.ReadBytes(&cie_id, sizeof(cie_id))) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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if (!IsCie32(cie_id)) {
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// This is not a Cie, something has gone horribly wrong.
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last_error_ = DWARF_ERROR_ILLEGAL_VALUE;
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return false;
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}
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}
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if (!memory_.ReadBytes(&cie->version, sizeof(cie->version))) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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if (cie->version != 1 && cie->version != 3 && cie->version != 4) {
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// Unrecognized version.
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last_error_ = DWARF_ERROR_UNSUPPORTED_VERSION;
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return false;
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}
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// Read the augmentation string.
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char aug_value;
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do {
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if (!memory_.ReadBytes(&aug_value, 1)) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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cie->augmentation_string.push_back(aug_value);
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} while (aug_value != '\0');
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if (cie->version == 4) {
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// Skip the Address Size field since we only use it for validation.
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memory_.set_cur_offset(memory_.cur_offset() + 1);
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// Segment Size
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if (!memory_.ReadBytes(&cie->segment_size, 1)) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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}
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// Code Alignment Factor
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if (!memory_.ReadULEB128(&cie->code_alignment_factor)) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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// Data Alignment Factor
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if (!memory_.ReadSLEB128(&cie->data_alignment_factor)) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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if (cie->version == 1) {
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// Return Address is a single byte.
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uint8_t return_address_register;
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if (!memory_.ReadBytes(&return_address_register, 1)) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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cie->return_address_register = return_address_register;
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} else if (!memory_.ReadULEB128(&cie->return_address_register)) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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if (cie->augmentation_string[0] != 'z') {
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cie->cfa_instructions_offset = memory_.cur_offset();
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return true;
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}
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uint64_t aug_length;
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if (!memory_.ReadULEB128(&aug_length)) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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cie->cfa_instructions_offset = memory_.cur_offset() + aug_length;
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for (size_t i = 1; i < cie->augmentation_string.size(); i++) {
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switch (cie->augmentation_string[i]) {
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case 'L':
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if (!memory_.ReadBytes(&cie->lsda_encoding, 1)) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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break;
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case 'P': {
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uint8_t encoding;
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if (!memory_.ReadBytes(&encoding, 1)) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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if (!memory_.ReadEncodedValue<AddressType>(encoding, &cie->personality_handler)) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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} break;
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case 'R':
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if (!memory_.ReadBytes(&cie->fde_address_encoding, 1)) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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break;
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}
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}
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return true;
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}
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template <typename AddressType>
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const DwarfFde* DwarfSectionImpl<AddressType>::GetFdeFromOffset(uint64_t offset) {
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auto fde_entry = fde_entries_.find(offset);
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if (fde_entry != fde_entries_.end()) {
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return &fde_entry->second;
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}
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DwarfFde* fde = &fde_entries_[offset];
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memory_.set_cur_offset(offset);
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if (!FillInFde(fde)) {
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fde_entries_.erase(offset);
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return nullptr;
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}
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return fde;
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}
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template <typename AddressType>
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bool DwarfSectionImpl<AddressType>::FillInFde(DwarfFde* fde) {
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uint32_t length32;
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if (!memory_.ReadBytes(&length32, sizeof(length32))) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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if (length32 == static_cast<uint32_t>(-1)) {
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// 64 bit Fde.
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uint64_t length64;
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if (!memory_.ReadBytes(&length64, sizeof(length64))) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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fde->cfa_instructions_end = memory_.cur_offset() + length64;
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uint64_t value64;
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if (!memory_.ReadBytes(&value64, sizeof(value64))) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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if (IsCie64(value64)) {
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// This is a Cie, this means something has gone wrong.
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last_error_ = DWARF_ERROR_ILLEGAL_VALUE;
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return false;
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}
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// Get the Cie pointer, which is necessary to properly read the rest of
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// of the Fde information.
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fde->cie_offset = GetCieOffsetFromFde64(value64);
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} else {
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// 32 bit Fde.
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fde->cfa_instructions_end = memory_.cur_offset() + length32;
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uint32_t value32;
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if (!memory_.ReadBytes(&value32, sizeof(value32))) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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if (IsCie32(value32)) {
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// This is a Cie, this means something has gone wrong.
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last_error_ = DWARF_ERROR_ILLEGAL_VALUE;
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return false;
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}
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// Get the Cie pointer, which is necessary to properly read the rest of
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// of the Fde information.
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fde->cie_offset = GetCieOffsetFromFde32(value32);
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}
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uint64_t cur_offset = memory_.cur_offset();
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const DwarfCie* cie = GetCie(fde->cie_offset);
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if (cie == nullptr) {
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return false;
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}
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fde->cie = cie;
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if (cie->segment_size != 0) {
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// Skip over the segment selector for now.
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cur_offset += cie->segment_size;
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}
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memory_.set_cur_offset(cur_offset);
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if (!memory_.ReadEncodedValue<AddressType>(cie->fde_address_encoding & 0xf, &fde->pc_start)) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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fde->pc_start = AdjustPcFromFde(fde->pc_start);
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if (!memory_.ReadEncodedValue<AddressType>(cie->fde_address_encoding & 0xf, &fde->pc_end)) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
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fde->pc_end += fde->pc_start;
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if (cie->augmentation_string.size() > 0 && cie->augmentation_string[0] == 'z') {
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// Augmentation Size
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uint64_t aug_length;
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if (!memory_.ReadULEB128(&aug_length)) {
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last_error_ = DWARF_ERROR_MEMORY_INVALID;
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return false;
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}
|
|
uint64_t cur_offset = memory_.cur_offset();
|
|
|
|
if (!memory_.ReadEncodedValue<AddressType>(cie->lsda_encoding, &fde->lsda_address)) {
|
|
last_error_ = DWARF_ERROR_MEMORY_INVALID;
|
|
return false;
|
|
}
|
|
|
|
// Set our position to after all of the augmentation data.
|
|
memory_.set_cur_offset(cur_offset + aug_length);
|
|
}
|
|
fde->cfa_instructions_offset = memory_.cur_offset();
|
|
|
|
return true;
|
|
}
|
|
|
|
template <typename AddressType>
|
|
bool DwarfSectionImpl<AddressType>::GetCfaLocationInfo(uint64_t pc, const DwarfFde* fde,
|
|
dwarf_loc_regs_t* loc_regs) {
|
|
DwarfCfa<AddressType> cfa(&memory_, fde);
|
|
|
|
// Look for the cached copy of the cie data.
|
|
auto reg_entry = cie_loc_regs_.find(fde->cie_offset);
|
|
if (reg_entry == cie_loc_regs_.end()) {
|
|
if (!cfa.GetLocationInfo(pc, fde->cie->cfa_instructions_offset, fde->cie->cfa_instructions_end,
|
|
loc_regs)) {
|
|
last_error_ = cfa.last_error();
|
|
return false;
|
|
}
|
|
cie_loc_regs_[fde->cie_offset] = *loc_regs;
|
|
}
|
|
cfa.set_cie_loc_regs(&cie_loc_regs_[fde->cie_offset]);
|
|
if (!cfa.GetLocationInfo(pc, fde->cfa_instructions_offset, fde->cfa_instructions_end, loc_regs)) {
|
|
last_error_ = cfa.last_error();
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
template <typename AddressType>
|
|
bool DwarfSectionImpl<AddressType>::Log(uint8_t indent, uint64_t pc, uint64_t load_bias,
|
|
const DwarfFde* fde) {
|
|
DwarfCfa<AddressType> cfa(&memory_, fde);
|
|
|
|
// Always print the cie information.
|
|
const DwarfCie* cie = fde->cie;
|
|
if (!cfa.Log(indent, pc, load_bias, cie->cfa_instructions_offset, cie->cfa_instructions_end)) {
|
|
last_error_ = cfa.last_error();
|
|
return false;
|
|
}
|
|
if (!cfa.Log(indent, pc, load_bias, fde->cfa_instructions_offset, fde->cfa_instructions_end)) {
|
|
last_error_ = cfa.last_error();
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
// Explicitly instantiate DwarfSectionImpl
|
|
template class DwarfSectionImpl<uint32_t>;
|
|
template class DwarfSectionImpl<uint64_t>;
|
|
|
|
} // namespace unwindstack
|