forked from OSchip/llvm-project
476 lines
18 KiB
C++
476 lines
18 KiB
C++
//===-- DWARFDebugLine.cpp ------------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "DWARFDebugLine.h"
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#include "llvm/Support/Dwarf.h"
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#include "llvm/Support/Format.h"
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#include "llvm/Support/raw_ostream.h"
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#include <algorithm>
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using namespace llvm;
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using namespace dwarf;
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void DWARFDebugLine::Prologue::dump(raw_ostream &OS) const {
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OS << "Line table prologue:\n"
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<< format(" total_length: 0x%8.8x\n", TotalLength)
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<< format(" version: %u\n", Version)
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<< format("prologue_length: 0x%8.8x\n", PrologueLength)
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<< format("min_inst_length: %u\n", MinInstLength)
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<< format("default_is_stmt: %u\n", DefaultIsStmt)
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<< format(" line_base: %i\n", LineBase)
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<< format(" line_range: %u\n", LineRange)
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<< format(" opcode_base: %u\n", OpcodeBase);
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for (uint32_t i = 0; i < StandardOpcodeLengths.size(); ++i)
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OS << format("standard_opcode_lengths[%s] = %u\n", LNStandardString(i+1),
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StandardOpcodeLengths[i]);
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if (!IncludeDirectories.empty())
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for (uint32_t i = 0; i < IncludeDirectories.size(); ++i)
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OS << format("include_directories[%3u] = '", i+1)
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<< IncludeDirectories[i] << "'\n";
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if (!FileNames.empty()) {
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OS << " Dir Mod Time File Len File Name\n"
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<< " ---- ---------- ---------- -----------"
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"----------------\n";
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for (uint32_t i = 0; i < FileNames.size(); ++i) {
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const FileNameEntry& fileEntry = FileNames[i];
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OS << format("file_names[%3u] %4u ", i+1, fileEntry.DirIdx)
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<< format("0x%8.8x 0x%8.8x ", fileEntry.ModTime, fileEntry.Length)
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<< fileEntry.Name << '\n';
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}
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}
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}
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void DWARFDebugLine::Row::postAppend() {
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BasicBlock = false;
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PrologueEnd = false;
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EpilogueBegin = false;
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}
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void DWARFDebugLine::Row::reset(bool default_is_stmt) {
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Address = 0;
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Line = 1;
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Column = 0;
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File = 1;
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Isa = 0;
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IsStmt = default_is_stmt;
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BasicBlock = false;
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EndSequence = false;
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PrologueEnd = false;
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EpilogueBegin = false;
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}
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void DWARFDebugLine::Row::dump(raw_ostream &OS) const {
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OS << format("0x%16.16llx %6u %6u", Address, Line, Column)
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<< format(" %6u %3u ", File, Isa)
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<< (IsStmt ? " is_stmt" : "")
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<< (BasicBlock ? " basic_block" : "")
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<< (PrologueEnd ? " prologue_end" : "")
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<< (EpilogueBegin ? " epilogue_begin" : "")
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<< (EndSequence ? " end_sequence" : "")
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<< '\n';
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}
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void DWARFDebugLine::LineTable::dump(raw_ostream &OS) const {
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Prologue.dump(OS);
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OS << '\n';
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if (!Rows.empty()) {
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OS << "Address Line Column File ISA Flags\n"
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<< "------------------ ------ ------ ------ --- -------------\n";
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for (std::vector<Row>::const_iterator pos = Rows.begin(),
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end = Rows.end(); pos != end; ++pos)
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pos->dump(OS);
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}
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}
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DWARFDebugLine::State::~State() {}
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void DWARFDebugLine::State::appendRowToMatrix(uint32_t offset) {
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++row; // Increase the row number.
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LineTable::appendRow(*this);
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Row::postAppend();
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}
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DWARFDebugLine::DumpingState::~DumpingState() {}
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void DWARFDebugLine::DumpingState::finalize(uint32_t offset) {
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LineTable::dump(OS);
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}
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const DWARFDebugLine::LineTable *
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DWARFDebugLine::getLineTable(uint32_t offset) const {
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LineTableConstIter pos = LineTableMap.find(offset);
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if (pos != LineTableMap.end())
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return &pos->second;
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return 0;
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}
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const DWARFDebugLine::LineTable *
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DWARFDebugLine::getOrParseLineTable(DataExtractor debug_line_data,
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uint32_t offset) {
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std::pair<LineTableIter, bool> pos =
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LineTableMap.insert(LineTableMapTy::value_type(offset, LineTable()));
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if (pos.second) {
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// Parse and cache the line table for at this offset.
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State state;
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if (!parseStatementTable(debug_line_data, &offset, state))
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return 0;
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pos.first->second = state;
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}
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return &pos.first->second;
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}
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bool
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DWARFDebugLine::parsePrologue(DataExtractor debug_line_data,
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uint32_t *offset_ptr, Prologue *prologue) {
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const uint32_t prologue_offset = *offset_ptr;
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prologue->clear();
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prologue->TotalLength = debug_line_data.getU32(offset_ptr);
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prologue->Version = debug_line_data.getU16(offset_ptr);
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if (prologue->Version != 2)
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return false;
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prologue->PrologueLength = debug_line_data.getU32(offset_ptr);
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const uint32_t end_prologue_offset = prologue->PrologueLength + *offset_ptr;
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prologue->MinInstLength = debug_line_data.getU8(offset_ptr);
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prologue->DefaultIsStmt = debug_line_data.getU8(offset_ptr);
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prologue->LineBase = debug_line_data.getU8(offset_ptr);
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prologue->LineRange = debug_line_data.getU8(offset_ptr);
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prologue->OpcodeBase = debug_line_data.getU8(offset_ptr);
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prologue->StandardOpcodeLengths.reserve(prologue->OpcodeBase-1);
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for (uint32_t i = 1; i < prologue->OpcodeBase; ++i) {
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uint8_t op_len = debug_line_data.getU8(offset_ptr);
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prologue->StandardOpcodeLengths.push_back(op_len);
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}
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while (*offset_ptr < end_prologue_offset) {
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const char *s = debug_line_data.getCStr(offset_ptr);
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if (s && s[0])
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prologue->IncludeDirectories.push_back(s);
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else
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break;
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}
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while (*offset_ptr < end_prologue_offset) {
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const char *name = debug_line_data.getCStr(offset_ptr);
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if (name && name[0]) {
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FileNameEntry fileEntry;
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fileEntry.Name = name;
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fileEntry.DirIdx = debug_line_data.getULEB128(offset_ptr);
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fileEntry.ModTime = debug_line_data.getULEB128(offset_ptr);
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fileEntry.Length = debug_line_data.getULEB128(offset_ptr);
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prologue->FileNames.push_back(fileEntry);
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} else {
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break;
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}
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}
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if (*offset_ptr != end_prologue_offset) {
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fprintf(stderr, "warning: parsing line table prologue at 0x%8.8x should"
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" have ended at 0x%8.8x but it ended ad 0x%8.8x\n",
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prologue_offset, end_prologue_offset, *offset_ptr);
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}
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return end_prologue_offset;
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}
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bool
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DWARFDebugLine::parseStatementTable(DataExtractor debug_line_data,
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uint32_t *offset_ptr, State &state) {
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const uint32_t debug_line_offset = *offset_ptr;
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Prologue *prologue = &state.Prologue;
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if (!parsePrologue(debug_line_data, offset_ptr, prologue)) {
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// Restore our offset and return false to indicate failure!
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*offset_ptr = debug_line_offset;
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return false;
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}
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const uint32_t end_offset = debug_line_offset + prologue->TotalLength +
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sizeof(prologue->TotalLength);
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state.reset();
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while (*offset_ptr < end_offset) {
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uint8_t opcode = debug_line_data.getU8(offset_ptr);
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if (opcode == 0) {
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// Extended Opcodes always start with a zero opcode followed by
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// a uleb128 length so you can skip ones you don't know about
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uint32_t ext_offset = *offset_ptr;
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uint64_t len = debug_line_data.getULEB128(offset_ptr);
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uint32_t arg_size = len - (*offset_ptr - ext_offset);
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uint8_t sub_opcode = debug_line_data.getU8(offset_ptr);
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switch (sub_opcode) {
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case DW_LNE_end_sequence:
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// Set the end_sequence register of the state machine to true and
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// append a row to the matrix using the current values of the
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// state-machine registers. Then reset the registers to the initial
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// values specified above. Every statement program sequence must end
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// with a DW_LNE_end_sequence instruction which creates a row whose
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// address is that of the byte after the last target machine instruction
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// of the sequence.
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state.EndSequence = true;
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state.appendRowToMatrix(*offset_ptr);
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state.reset();
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break;
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case DW_LNE_set_address:
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// Takes a single relocatable address as an operand. The size of the
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// operand is the size appropriate to hold an address on the target
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// machine. Set the address register to the value given by the
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// relocatable address. All of the other statement program opcodes
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// that affect the address register add a delta to it. This instruction
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// stores a relocatable value into it instead.
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state.Address = debug_line_data.getAddress(offset_ptr);
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break;
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case DW_LNE_define_file:
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// Takes 4 arguments. The first is a null terminated string containing
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// a source file name. The second is an unsigned LEB128 number
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// representing the directory index of the directory in which the file
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// was found. The third is an unsigned LEB128 number representing the
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// time of last modification of the file. The fourth is an unsigned
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// LEB128 number representing the length in bytes of the file. The time
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// and length fields may contain LEB128(0) if the information is not
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// available.
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//
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// The directory index represents an entry in the include_directories
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// section of the statement program prologue. The index is LEB128(0)
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// if the file was found in the current directory of the compilation,
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// LEB128(1) if it was found in the first directory in the
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// include_directories section, and so on. The directory index is
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// ignored for file names that represent full path names.
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//
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// The files are numbered, starting at 1, in the order in which they
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// appear; the names in the prologue come before names defined by
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// the DW_LNE_define_file instruction. These numbers are used in the
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// the file register of the state machine.
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{
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FileNameEntry fileEntry;
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fileEntry.Name = debug_line_data.getCStr(offset_ptr);
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fileEntry.DirIdx = debug_line_data.getULEB128(offset_ptr);
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fileEntry.ModTime = debug_line_data.getULEB128(offset_ptr);
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fileEntry.Length = debug_line_data.getULEB128(offset_ptr);
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prologue->FileNames.push_back(fileEntry);
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}
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break;
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default:
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// Length doesn't include the zero opcode byte or the length itself, but
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// it does include the sub_opcode, so we have to adjust for that below
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(*offset_ptr) += arg_size;
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break;
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}
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} else if (opcode < prologue->OpcodeBase) {
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switch (opcode) {
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// Standard Opcodes
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case DW_LNS_copy:
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// Takes no arguments. Append a row to the matrix using the
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// current values of the state-machine registers. Then set
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// the basic_block register to false.
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state.appendRowToMatrix(*offset_ptr);
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break;
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case DW_LNS_advance_pc:
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// Takes a single unsigned LEB128 operand, multiplies it by the
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// min_inst_length field of the prologue, and adds the
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// result to the address register of the state machine.
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state.Address += debug_line_data.getULEB128(offset_ptr) *
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prologue->MinInstLength;
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break;
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case DW_LNS_advance_line:
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// Takes a single signed LEB128 operand and adds that value to
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// the line register of the state machine.
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state.Line += debug_line_data.getSLEB128(offset_ptr);
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break;
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case DW_LNS_set_file:
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// Takes a single unsigned LEB128 operand and stores it in the file
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// register of the state machine.
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state.File = debug_line_data.getULEB128(offset_ptr);
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break;
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case DW_LNS_set_column:
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// Takes a single unsigned LEB128 operand and stores it in the
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// column register of the state machine.
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state.Column = debug_line_data.getULEB128(offset_ptr);
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break;
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case DW_LNS_negate_stmt:
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// Takes no arguments. Set the is_stmt register of the state
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// machine to the logical negation of its current value.
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state.IsStmt = !state.IsStmt;
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break;
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case DW_LNS_set_basic_block:
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// Takes no arguments. Set the basic_block register of the
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// state machine to true
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state.BasicBlock = true;
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break;
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case DW_LNS_const_add_pc:
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// Takes no arguments. Add to the address register of the state
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// machine the address increment value corresponding to special
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// opcode 255. The motivation for DW_LNS_const_add_pc is this:
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// when the statement program needs to advance the address by a
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// small amount, it can use a single special opcode, which occupies
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// a single byte. When it needs to advance the address by up to
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// twice the range of the last special opcode, it can use
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// DW_LNS_const_add_pc followed by a special opcode, for a total
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// of two bytes. Only if it needs to advance the address by more
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// than twice that range will it need to use both DW_LNS_advance_pc
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// and a special opcode, requiring three or more bytes.
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{
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uint8_t adjust_opcode = 255 - prologue->OpcodeBase;
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uint64_t addr_offset = (adjust_opcode / prologue->LineRange) *
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prologue->MinInstLength;
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state.Address += addr_offset;
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}
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break;
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case DW_LNS_fixed_advance_pc:
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// Takes a single uhalf operand. Add to the address register of
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// the state machine the value of the (unencoded) operand. This
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// is the only extended opcode that takes an argument that is not
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// a variable length number. The motivation for DW_LNS_fixed_advance_pc
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// is this: existing assemblers cannot emit DW_LNS_advance_pc or
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// special opcodes because they cannot encode LEB128 numbers or
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// judge when the computation of a special opcode overflows and
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// requires the use of DW_LNS_advance_pc. Such assemblers, however,
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// can use DW_LNS_fixed_advance_pc instead, sacrificing compression.
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state.Address += debug_line_data.getU16(offset_ptr);
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break;
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case DW_LNS_set_prologue_end:
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// Takes no arguments. Set the prologue_end register of the
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// state machine to true
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state.PrologueEnd = true;
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break;
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case DW_LNS_set_epilogue_begin:
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// Takes no arguments. Set the basic_block register of the
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// state machine to true
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state.EpilogueBegin = true;
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break;
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case DW_LNS_set_isa:
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// Takes a single unsigned LEB128 operand and stores it in the
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// column register of the state machine.
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state.Isa = debug_line_data.getULEB128(offset_ptr);
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break;
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default:
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// Handle any unknown standard opcodes here. We know the lengths
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// of such opcodes because they are specified in the prologue
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// as a multiple of LEB128 operands for each opcode.
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{
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assert(opcode - 1U < prologue->StandardOpcodeLengths.size());
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uint8_t opcode_length = prologue->StandardOpcodeLengths[opcode - 1];
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for (uint8_t i=0; i<opcode_length; ++i)
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debug_line_data.getULEB128(offset_ptr);
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}
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break;
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}
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} else {
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// Special Opcodes
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// A special opcode value is chosen based on the amount that needs
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// to be added to the line and address registers. The maximum line
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// increment for a special opcode is the value of the line_base
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// field in the header, plus the value of the line_range field,
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// minus 1 (line base + line range - 1). If the desired line
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// increment is greater than the maximum line increment, a standard
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// opcode must be used instead of a special opcode. The "address
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// advance" is calculated by dividing the desired address increment
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// by the minimum_instruction_length field from the header. The
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// special opcode is then calculated using the following formula:
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//
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// opcode = (desired line increment - line_base) +
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// (line_range * address advance) + opcode_base
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//
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// If the resulting opcode is greater than 255, a standard opcode
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// must be used instead.
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//
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// To decode a special opcode, subtract the opcode_base from the
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// opcode itself to give the adjusted opcode. The amount to
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// increment the address register is the result of the adjusted
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// opcode divided by the line_range multiplied by the
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// minimum_instruction_length field from the header. That is:
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//
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// address increment = (adjusted opcode / line_range) *
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// minimum_instruction_length
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//
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// The amount to increment the line register is the line_base plus
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// the result of the adjusted opcode modulo the line_range. That is:
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//
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// line increment = line_base + (adjusted opcode % line_range)
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uint8_t adjust_opcode = opcode - prologue->OpcodeBase;
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uint64_t addr_offset = (adjust_opcode / prologue->LineRange) *
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prologue->MinInstLength;
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int32_t line_offset = prologue->LineBase +
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(adjust_opcode % prologue->LineRange);
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state.Line += line_offset;
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state.Address += addr_offset;
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state.appendRowToMatrix(*offset_ptr);
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}
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}
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state.finalize(*offset_ptr);
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return end_offset;
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}
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static bool findMatchingAddress(const DWARFDebugLine::Row& row1,
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const DWARFDebugLine::Row& row2) {
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return row1.Address < row2.Address;
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}
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uint32_t
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DWARFDebugLine::LineTable::lookupAddress(uint64_t address,
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uint64_t cu_high_pc) const {
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uint32_t index = UINT32_MAX;
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if (!Rows.empty()) {
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// Use the lower_bound algorithm to perform a binary search since we know
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// that our line table data is ordered by address.
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DWARFDebugLine::Row row;
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row.Address = address;
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typedef std::vector<Row>::const_iterator iterator;
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iterator begin_pos = Rows.begin();
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iterator end_pos = Rows.end();
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iterator pos = std::lower_bound(begin_pos, end_pos, row,
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findMatchingAddress);
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if (pos == end_pos) {
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|
if (address < cu_high_pc)
|
|
return Rows.size()-1;
|
|
} else {
|
|
// Rely on fact that we are using a std::vector and we can do
|
|
// pointer arithmetic to find the row index (which will be one less
|
|
// that what we found since it will find the first position after
|
|
// the current address) since std::vector iterators are just
|
|
// pointers to the container type.
|
|
index = pos - begin_pos;
|
|
if (pos->Address > address) {
|
|
if (index > 0)
|
|
--index;
|
|
else
|
|
index = UINT32_MAX;
|
|
}
|
|
}
|
|
}
|
|
return index; // Failed to find address.
|
|
}
|