The Tor Browser: comparison toolkit/crashreporter/google-breakpad/src/common/dwarf/dwarf2reader.cc

--1:000000000000
+:e074cff804de
+// Copyright (c) 2010 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+// CFI reader author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com>
+// Implementation of dwarf2reader::LineInfo, dwarf2reader::CompilationUnit,
+// and dwarf2reader::CallFrameInfo. See dwarf2reader.h for details.
+#include "common/dwarf/dwarf2reader.h"
+#include <assert.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <map>
+#include <memory>
+#include <stack>
+#include <string>
+#include <utility>
+#include "common/dwarf/bytereader-inl.h"
+#include "common/dwarf/bytereader.h"
+#include "common/dwarf/line_state_machine.h"
+#include "common/using_std_string.h"
+namespace dwarf2reader {
+CompilationUnit::CompilationUnit(const SectionMap& sections, uint64 offset,
+ByteReader* reader, Dwarf2Handler* handler)
+: offset_from_section_start_(offset), reader_(reader),
+sections_(sections), handler_(handler), abbrevs_(NULL),
+string_buffer_(NULL), string_buffer_length_(0) {}
+// Read a DWARF2/3 abbreviation section.
+// Each abbrev consists of a abbreviation number, a tag, a byte
+// specifying whether the tag has children, and a list of
+// attribute/form pairs.
+// The list of forms is terminated by a 0 for the attribute, and a
+// zero for the form.  The entire abbreviation section is terminated
+// by a zero for the code.
+void CompilationUnit::ReadAbbrevs() {
+if (abbrevs_)
+return;
+// First get the debug_abbrev section.  ".debug_abbrev" is the name
+// recommended in the DWARF spec, and used on Linux;
+// "__debug_abbrev" is the name used in Mac OS X Mach-O files.
+SectionMap::const_iterator iter = sections_.find(".debug_abbrev");
+if (iter == sections_.end())
+iter = sections_.find("__debug_abbrev");
+assert(iter != sections_.end());
+abbrevs_ = new std::vector<Abbrev>;
+abbrevs_->resize(1);
+// The only way to check whether we are reading over the end of the
+// buffer would be to first compute the size of the leb128 data by
+// reading it, then go back and read it again.
+const char* abbrev_start = iter->second.first +
+header_.abbrev_offset;
+const char* abbrevptr = abbrev_start;
+#ifndef NDEBUG
+const uint64 abbrev_length = iter->second.second - header_.abbrev_offset;
+#endif
+while (1) {
+CompilationUnit::Abbrev abbrev;
+size_t len;
+const uint64 number = reader_->ReadUnsignedLEB128(abbrevptr, &len);
+if (number == 0)
+break;
+abbrev.number = number;
+abbrevptr += len;
+assert(abbrevptr < abbrev_start + abbrev_length);
+const uint64 tag = reader_->ReadUnsignedLEB128(abbrevptr, &len);
+abbrevptr += len;
+abbrev.tag = static_cast<enum DwarfTag>(tag);
+assert(abbrevptr < abbrev_start + abbrev_length);
+abbrev.has_children = reader_->ReadOneByte(abbrevptr);
+abbrevptr += 1;
+assert(abbrevptr < abbrev_start + abbrev_length);
+while (1) {
+const uint64 nametemp = reader_->ReadUnsignedLEB128(abbrevptr, &len);
+abbrevptr += len;
+assert(abbrevptr < abbrev_start + abbrev_length);
+const uint64 formtemp = reader_->ReadUnsignedLEB128(abbrevptr, &len);
+abbrevptr += len;
+if (nametemp == 0 && formtemp == 0)
+break;
+const enum DwarfAttribute name =
+static_cast<enum DwarfAttribute>(nametemp);
+const enum DwarfForm form = static_cast<enum DwarfForm>(formtemp);
+abbrev.attributes.push_back(std::make_pair(name, form));
+}
+assert(abbrev.number == abbrevs_->size());
+abbrevs_->push_back(abbrev);
+}
+}
+// Skips a single DIE's attributes.
+const char* CompilationUnit::SkipDIE(const char* start,
+const Abbrev& abbrev) {
+for (AttributeList::const_iterator i = abbrev.attributes.begin();
+i != abbrev.attributes.end();
+i++)  {
+start = SkipAttribute(start, i->second);
+}
+return start;
+}
+// Skips a single attribute form's data.
+const char* CompilationUnit::SkipAttribute(const char* start,
+enum DwarfForm form) {
+size_t len;
+switch (form) {
+case DW_FORM_indirect:
+form = static_cast<enum DwarfForm>(reader_->ReadUnsignedLEB128(start,
+&len));
+start += len;
+return SkipAttribute(start, form);
+case DW_FORM_flag_present:
+return start;
+case DW_FORM_data1:
+case DW_FORM_flag:
+case DW_FORM_ref1:
+return start + 1;
+case DW_FORM_ref2:
+case DW_FORM_data2:
+return start + 2;
+case DW_FORM_ref4:
+case DW_FORM_data4:
+return start + 4;
+case DW_FORM_ref8:
+case DW_FORM_data8:
+case DW_FORM_ref_sig8:
+return start + 8;
+case DW_FORM_string:
+return start + strlen(start) + 1;
+case DW_FORM_udata:
+case DW_FORM_ref_udata:
+reader_->ReadUnsignedLEB128(start, &len);
+return start + len;
+case DW_FORM_sdata:
+reader_->ReadSignedLEB128(start, &len);
+return start + len;
+case DW_FORM_addr:
+return start + reader_->AddressSize();
+case DW_FORM_ref_addr:
+// DWARF2 and 3 differ on whether ref_addr is address size or
+// offset size.
+assert(header_.version == 2 || header_.version == 3);
+if (header_.version == 2) {
+return start + reader_->AddressSize();
+} else if (header_.version == 3) {
+return start + reader_->OffsetSize();
+}
+case DW_FORM_block1:
+return start + 1 + reader_->ReadOneByte(start);
+case DW_FORM_block2:
+return start + 2 + reader_->ReadTwoBytes(start);
+case DW_FORM_block4:
+return start + 4 + reader_->ReadFourBytes(start);
+case DW_FORM_block:
+case DW_FORM_exprloc: {
+uint64 size = reader_->ReadUnsignedLEB128(start, &len);
+return start + size + len;
+}
+case DW_FORM_strp:
+case DW_FORM_sec_offset:
+return start + reader_->OffsetSize();
+}
+fprintf(stderr,"Unhandled form type");
+return NULL;
+}
+// Read a DWARF2/3 header.
+// The header is variable length in DWARF3 (and DWARF2 as extended by
+// most compilers), and consists of an length field, a version number,
+// the offset in the .debug_abbrev section for our abbrevs, and an
+// address size.
+void CompilationUnit::ReadHeader() {
+const char* headerptr = buffer_;
+size_t initial_length_size;
+assert(headerptr + 4 < buffer_ + buffer_length_);
+const uint64 initial_length
+= reader_->ReadInitialLength(headerptr, &initial_length_size);
+headerptr += initial_length_size;
+header_.length = initial_length;
+assert(headerptr + 2 < buffer_ + buffer_length_);
+header_.version = reader_->ReadTwoBytes(headerptr);
+headerptr += 2;
+assert(headerptr + reader_->OffsetSize() < buffer_ + buffer_length_);
+header_.abbrev_offset = reader_->ReadOffset(headerptr);
+headerptr += reader_->OffsetSize();
+assert(headerptr + 1 < buffer_ + buffer_length_);
+header_.address_size = reader_->ReadOneByte(headerptr);
+reader_->SetAddressSize(header_.address_size);
+headerptr += 1;
+after_header_ = headerptr;
+// This check ensures that we don't have to do checking during the
+// reading of DIEs. header_.length does not include the size of the
+// initial length.
+assert(buffer_ + initial_length_size + header_.length <=
+buffer_ + buffer_length_);
+}
+uint64 CompilationUnit::Start() {
+// First get the debug_info section.  ".debug_info" is the name
+// recommended in the DWARF spec, and used on Linux; "__debug_info"
+// is the name used in Mac OS X Mach-O files.
+SectionMap::const_iterator iter = sections_.find(".debug_info");
+if (iter == sections_.end())
+iter = sections_.find("__debug_info");
+assert(iter != sections_.end());
+// Set up our buffer
+buffer_ = iter->second.first + offset_from_section_start_;
+buffer_length_ = iter->second.second - offset_from_section_start_;
+// Read the header
+ReadHeader();
+// Figure out the real length from the end of the initial length to
+// the end of the compilation unit, since that is the value we
+// return.
+uint64 ourlength = header_.length;
+if (reader_->OffsetSize() == 8)
+ourlength += 12;
+else
+ourlength += 4;
+// See if the user wants this compilation unit, and if not, just return.
+if (!handler_->StartCompilationUnit(offset_from_section_start_,
+reader_->AddressSize(),
+reader_->OffsetSize(),
+header_.length,
+header_.version))
+return ourlength;
+// Otherwise, continue by reading our abbreviation entries.
+ReadAbbrevs();
+// Set the string section if we have one.  ".debug_str" is the name
+// recommended in the DWARF spec, and used on Linux; "__debug_str"
+// is the name used in Mac OS X Mach-O files.
+iter = sections_.find(".debug_str");
+if (iter == sections_.end())
+iter = sections_.find("__debug_str");
+if (iter != sections_.end()) {
+string_buffer_ = iter->second.first;
+string_buffer_length_ = iter->second.second;
+}
+// Now that we have our abbreviations, start processing DIE's.
+ProcessDIEs();
+return ourlength;
+}
+// If one really wanted, you could merge SkipAttribute and
+// ProcessAttribute
+// This is all boring data manipulation and calling of the handler.
+const char* CompilationUnit::ProcessAttribute(
+uint64 dieoffset, const char* start, enum DwarfAttribute attr,
+enum DwarfForm form) {
+size_t len;
+switch (form) {
+// DW_FORM_indirect is never used because it is such a space
+// waster.
+case DW_FORM_indirect:
+form = static_cast<enum DwarfForm>(reader_->ReadUnsignedLEB128(start,
+&len));
+start += len;
+return ProcessAttribute(dieoffset, start, attr, form);
+case DW_FORM_flag_present:
+handler_->ProcessAttributeUnsigned(dieoffset, attr, form, 1);
+return start;
+case DW_FORM_data1:
+case DW_FORM_flag:
+handler_->ProcessAttributeUnsigned(dieoffset, attr, form,
+reader_->ReadOneByte(start));
+return start + 1;
+case DW_FORM_data2:
+handler_->ProcessAttributeUnsigned(dieoffset, attr, form,
+reader_->ReadTwoBytes(start));
+return start + 2;
+case DW_FORM_data4:
+handler_->ProcessAttributeUnsigned(dieoffset, attr, form,
+reader_->ReadFourBytes(start));
+return start + 4;
+case DW_FORM_data8:
+handler_->ProcessAttributeUnsigned(dieoffset, attr, form,
+reader_->ReadEightBytes(start));
+return start + 8;
+case DW_FORM_string: {
+const char* str = start;
+handler_->ProcessAttributeString(dieoffset, attr, form,
+str);
+return start + strlen(str) + 1;
+}
+case DW_FORM_udata:
+handler_->ProcessAttributeUnsigned(dieoffset, attr, form,
+reader_->ReadUnsignedLEB128(start,
+&len));
+return start + len;
+case DW_FORM_sdata:
+handler_->ProcessAttributeSigned(dieoffset, attr, form,
+reader_->ReadSignedLEB128(start, &len));
+return start + len;
+case DW_FORM_addr:
+handler_->ProcessAttributeUnsigned(dieoffset, attr, form,
+reader_->ReadAddress(start));
+return start + reader_->AddressSize();
+case DW_FORM_sec_offset:
+handler_->ProcessAttributeUnsigned(dieoffset, attr, form,
+reader_->ReadOffset(start));
+return start + reader_->OffsetSize();
+case DW_FORM_ref1:
+handler_->ProcessAttributeReference(dieoffset, attr, form,
+reader_->ReadOneByte(start)
++ offset_from_section_start_);
+return start + 1;
+case DW_FORM_ref2:
+handler_->ProcessAttributeReference(dieoffset, attr, form,
+reader_->ReadTwoBytes(start)
++ offset_from_section_start_);
+return start + 2;
+case DW_FORM_ref4:
+handler_->ProcessAttributeReference(dieoffset, attr, form,
+reader_->ReadFourBytes(start)
++ offset_from_section_start_);
+return start + 4;
+case DW_FORM_ref8:
+handler_->ProcessAttributeReference(dieoffset, attr, form,
+reader_->ReadEightBytes(start)
++ offset_from_section_start_);
+return start + 8;
+case DW_FORM_ref_udata:
+handler_->ProcessAttributeReference(dieoffset, attr, form,
+reader_->ReadUnsignedLEB128(start,
+&len)
++ offset_from_section_start_);
+return start + len;
+case DW_FORM_ref_addr:
+// DWARF2 and 3 differ on whether ref_addr is address size or
+// offset size.
+assert(header_.version == 2 || header_.version == 3);
+if (header_.version == 2) {
+handler_->ProcessAttributeReference(dieoffset, attr, form,
+reader_->ReadAddress(start));
+return start + reader_->AddressSize();
+} else if (header_.version == 3) {
+handler_->ProcessAttributeReference(dieoffset, attr, form,
+reader_->ReadOffset(start));
+return start + reader_->OffsetSize();
+}
+break;
+case DW_FORM_ref_sig8:
+handler_->ProcessAttributeSignature(dieoffset, attr, form,
+reader_->ReadEightBytes(start));
+return start + 8;
+case DW_FORM_block1: {
+uint64 datalen = reader_->ReadOneByte(start);
+handler_->ProcessAttributeBuffer(dieoffset, attr, form, start + 1,
+datalen);
+return start + 1 + datalen;
+}
+case DW_FORM_block2: {
+uint64 datalen = reader_->ReadTwoBytes(start);
+handler_->ProcessAttributeBuffer(dieoffset, attr, form, start + 2,
+datalen);
+return start + 2 + datalen;
+}
+case DW_FORM_block4: {
+uint64 datalen = reader_->ReadFourBytes(start);
+handler_->ProcessAttributeBuffer(dieoffset, attr, form, start + 4,
+datalen);
+return start + 4 + datalen;
+}
+case DW_FORM_block:
+case DW_FORM_exprloc: {
+uint64 datalen = reader_->ReadUnsignedLEB128(start, &len);
+handler_->ProcessAttributeBuffer(dieoffset, attr, form, start + len,
+datalen);
+return start + datalen + len;
+}
+case DW_FORM_strp: {
+assert(string_buffer_ != NULL);
+const uint64 offset = reader_->ReadOffset(start);
+assert(string_buffer_ + offset < string_buffer_ + string_buffer_length_);
+const char* str = string_buffer_ + offset;
+handler_->ProcessAttributeString(dieoffset, attr, form,
+str);
+return start + reader_->OffsetSize();
+}
+}
+fprintf(stderr, "Unhandled form type\n");
+return NULL;
+}
+const char* CompilationUnit::ProcessDIE(uint64 dieoffset,
+const char* start,
+const Abbrev& abbrev) {
+for (AttributeList::const_iterator i = abbrev.attributes.begin();
+i != abbrev.attributes.end();
+i++)  {
+start = ProcessAttribute(dieoffset, start, i->first, i->second);
+}
+return start;
+}
+void CompilationUnit::ProcessDIEs() {
+const char* dieptr = after_header_;
+size_t len;
+// lengthstart is the place the length field is based on.
+// It is the point in the header after the initial length field
+const char* lengthstart = buffer_;
+// In 64 bit dwarf, the initial length is 12 bytes, because of the
+// 0xffffffff at the start.
+if (reader_->OffsetSize() == 8)
+lengthstart += 12;
+else
+lengthstart += 4;
+std::stack<uint64> die_stack;
+while (dieptr < (lengthstart + header_.length)) {
+// We give the user the absolute offset from the beginning of
+// debug_info, since they need it to deal with ref_addr forms.
+uint64 absolute_offset = (dieptr - buffer_) + offset_from_section_start_;
+uint64 abbrev_num = reader_->ReadUnsignedLEB128(dieptr, &len);
+dieptr += len;
+// Abbrev == 0 represents the end of a list of children, or padding
+// at the end of the compilation unit.
+if (abbrev_num == 0) {
+if (die_stack.size() == 0)
+// If it is padding, then we are done with the compilation unit's DIEs.
+return;
+const uint64 offset = die_stack.top();
+die_stack.pop();
+handler_->EndDIE(offset);
+continue;
+}
+const Abbrev& abbrev = abbrevs_->at(static_cast<size_t>(abbrev_num));
+const enum DwarfTag tag = abbrev.tag;
+if (!handler_->StartDIE(absolute_offset, tag)) {
+dieptr = SkipDIE(dieptr, abbrev);
+} else {
+dieptr = ProcessDIE(absolute_offset, dieptr, abbrev);
+}
+if (abbrev.has_children) {
+die_stack.push(absolute_offset);
+} else {
+handler_->EndDIE(absolute_offset);
+}
+}
+}
+LineInfo::LineInfo(const char* buffer, uint64 buffer_length,
+ByteReader* reader, LineInfoHandler* handler):
+handler_(handler), reader_(reader), buffer_(buffer),
+buffer_length_(buffer_length) {
+header_.std_opcode_lengths = NULL;
+}
+uint64 LineInfo::Start() {
+ReadHeader();
+ReadLines();
+return after_header_ - buffer_;
+}
+// The header for a debug_line section is mildly complicated, because
+// the line info is very tightly encoded.
+void LineInfo::ReadHeader() {
+const char* lineptr = buffer_;
+size_t initial_length_size;
+const uint64 initial_length
+= reader_->ReadInitialLength(lineptr, &initial_length_size);
+lineptr += initial_length_size;
+header_.total_length = initial_length;
+assert(buffer_ + initial_length_size + header_.total_length <=
+buffer_ + buffer_length_);
+// Address size *must* be set by CU ahead of time.
+assert(reader_->AddressSize() != 0);
+header_.version = reader_->ReadTwoBytes(lineptr);
+lineptr += 2;
+header_.prologue_length = reader_->ReadOffset(lineptr);
+lineptr += reader_->OffsetSize();
+header_.min_insn_length = reader_->ReadOneByte(lineptr);
+lineptr += 1;
+header_.default_is_stmt = reader_->ReadOneByte(lineptr);
+lineptr += 1;
+header_.line_base = *reinterpret_cast<const int8*>(lineptr);
+lineptr += 1;
+header_.line_range = reader_->ReadOneByte(lineptr);
+lineptr += 1;
+header_.opcode_base = reader_->ReadOneByte(lineptr);
+lineptr += 1;
+header_.std_opcode_lengths = new std::vector<unsigned char>;
+header_.std_opcode_lengths->resize(header_.opcode_base + 1);
+(*header_.std_opcode_lengths)[0] = 0;
+for (int i = 1; i < header_.opcode_base; i++) {
+(*header_.std_opcode_lengths)[i] = reader_->ReadOneByte(lineptr);
+lineptr += 1;
+}
+// It is legal for the directory entry table to be empty.
+if (*lineptr) {
+uint32 dirindex = 1;
+while (*lineptr) {
+const char* dirname = lineptr;
+handler_->DefineDir(dirname, dirindex);
+lineptr += strlen(dirname) + 1;
+dirindex++;
+}
+}
+lineptr++;
+// It is also legal for the file entry table to be empty.
+if (*lineptr) {
+uint32 fileindex = 1;
+size_t len;
+while (*lineptr) {
+const char* filename = lineptr;
+lineptr += strlen(filename) + 1;
+uint64 dirindex = reader_->ReadUnsignedLEB128(lineptr, &len);
+lineptr += len;
+uint64 mod_time = reader_->ReadUnsignedLEB128(lineptr, &len);
+lineptr += len;
+uint64 filelength = reader_->ReadUnsignedLEB128(lineptr, &len);
+lineptr += len;
+handler_->DefineFile(filename, fileindex, static_cast<uint32>(dirindex),
+mod_time, filelength);
+fileindex++;
+}
+}
+lineptr++;
+after_header_ = lineptr;
+}
+/* static */
+bool LineInfo::ProcessOneOpcode(ByteReader* reader,
+LineInfoHandler* handler,
+const struct LineInfoHeader &header,
+const char* start,
+struct LineStateMachine* lsm,
+size_t* len,
+uintptr pc,
+bool *lsm_passes_pc) {
+size_t oplen = 0;
+size_t templen;
+uint8 opcode = reader->ReadOneByte(start);
+oplen++;
+start++;
+// If the opcode is great than the opcode_base, it is a special
+// opcode. Most line programs consist mainly of special opcodes.
+if (opcode >= header.opcode_base) {
+opcode -= header.opcode_base;
+const int64 advance_address = (opcode / header.line_range)
+* header.min_insn_length;
+const int32 advance_line = (opcode % header.line_range)
++ header.line_base;
+// Check if the lsm passes "pc". If so, mark it as passed.
+if (lsm_passes_pc &&
+lsm->address <= pc && pc < lsm->address + advance_address) {
+*lsm_passes_pc = true;
+}
+lsm->address += advance_address;
+lsm->line_num += advance_line;
+lsm->basic_block = true;
+*len = oplen;
+return true;
+}
+// Otherwise, we have the regular opcodes
+switch (opcode) {
+case DW_LNS_copy: {
+lsm->basic_block = false;
+*len = oplen;
+return true;
+}
+case DW_LNS_advance_pc: {
+uint64 advance_address = reader->ReadUnsignedLEB128(start, &templen);
+oplen += templen;
+// Check if the lsm passes "pc". If so, mark it as passed.
+if (lsm_passes_pc && lsm->address <= pc &&
+pc < lsm->address + header.min_insn_length * advance_address) {
+*lsm_passes_pc = true;
+}
+lsm->address += header.min_insn_length * advance_address;
+}
+break;
+case DW_LNS_advance_line: {
+const int64 advance_line = reader->ReadSignedLEB128(start, &templen);
+oplen += templen;
+lsm->line_num += static_cast<int32>(advance_line);
+// With gcc 4.2.1, we can get the line_no here for the first time
+// since DW_LNS_advance_line is called after DW_LNE_set_address is
+// called. So we check if the lsm passes "pc" here, not in
+// DW_LNE_set_address.
+if (lsm_passes_pc && lsm->address == pc) {
+*lsm_passes_pc = true;
+}
+}
+break;
+case DW_LNS_set_file: {
+const uint64 fileno = reader->ReadUnsignedLEB128(start, &templen);
+oplen += templen;
+lsm->file_num = static_cast<uint32>(fileno);
+}
+break;
+case DW_LNS_set_column: {
+const uint64 colno = reader->ReadUnsignedLEB128(start, &templen);
+oplen += templen;
+lsm->column_num = static_cast<uint32>(colno);
+}
+break;
+case DW_LNS_negate_stmt: {
+lsm->is_stmt = !lsm->is_stmt;
+}
+break;
+case DW_LNS_set_basic_block: {
+lsm->basic_block = true;
+}
+break;
+case DW_LNS_fixed_advance_pc: {
+const uint16 advance_address = reader->ReadTwoBytes(start);
+oplen += 2;
+// Check if the lsm passes "pc". If so, mark it as passed.
+if (lsm_passes_pc &&
+lsm->address <= pc && pc < lsm->address + advance_address) {
+*lsm_passes_pc = true;
+}
+lsm->address += advance_address;
+}
+break;
+case DW_LNS_const_add_pc: {
+const int64 advance_address = header.min_insn_length
+* ((255 - header.opcode_base)
+/ header.line_range);
+// Check if the lsm passes "pc". If so, mark it as passed.
+if (lsm_passes_pc &&
+lsm->address <= pc && pc < lsm->address + advance_address) {
+*lsm_passes_pc = true;
+}
+lsm->address += advance_address;
+}
+break;
+case DW_LNS_extended_op: {
+const uint64 extended_op_len = reader->ReadUnsignedLEB128(start,
+&templen);
+start += templen;
+oplen += templen + extended_op_len;
+const uint64 extended_op = reader->ReadOneByte(start);
+start++;
+switch (extended_op) {
+case DW_LNE_end_sequence: {
+lsm->end_sequence = true;
+*len = oplen;
+return true;
+}
+break;
+case DW_LNE_set_address: {
+// With gcc 4.2.1, we cannot tell the line_no here since
+// DW_LNE_set_address is called before DW_LNS_advance_line is
+// called.  So we do not check if the lsm passes "pc" here.  See
+// also the comment in DW_LNS_advance_line.
+uint64 address = reader->ReadAddress(start);
+lsm->address = address;
+}
+break;
+case DW_LNE_define_file: {
+const char* filename  = start;
+templen = strlen(filename) + 1;
+start += templen;
+uint64 dirindex = reader->ReadUnsignedLEB128(start, &templen);
+oplen += templen;
+const uint64 mod_time = reader->ReadUnsignedLEB128(start,
+&templen);
+oplen += templen;
+const uint64 filelength = reader->ReadUnsignedLEB128(start,
+&templen);
+oplen += templen;
+if (handler) {
+handler->DefineFile(filename, -1, static_cast<uint32>(dirindex),
+mod_time, filelength);
+}
+}
+break;
+}
+}
+break;
+default: {
+// Ignore unknown opcode  silently
+if (header.std_opcode_lengths) {
+for (int i = 0; i < (*header.std_opcode_lengths)[opcode]; i++) {
+reader->ReadUnsignedLEB128(start, &templen);
+start += templen;
+oplen += templen;
+}
+}
+}
+break;
+}
+*len = oplen;
+return false;
+}
+void LineInfo::ReadLines() {
+struct LineStateMachine lsm;
+// lengthstart is the place the length field is based on.
+// It is the point in the header after the initial length field
+const char* lengthstart = buffer_;
+// In 64 bit dwarf, the initial length is 12 bytes, because of the
+// 0xffffffff at the start.
+if (reader_->OffsetSize() == 8)
+lengthstart += 12;
+else
+lengthstart += 4;
+const char* lineptr = after_header_;
+lsm.Reset(header_.default_is_stmt);
+// The LineInfoHandler interface expects each line's length along
+// with its address, but DWARF only provides addresses (sans
+// length), and an end-of-sequence address; one infers the length
+// from the next address. So we report a line only when we get the
+// next line's address, or the end-of-sequence address.
+bool have_pending_line = false;
+uint64 pending_address = 0;
+uint32 pending_file_num = 0, pending_line_num = 0, pending_column_num = 0;
+while (lineptr < lengthstart + header_.total_length) {
+size_t oplength;
+bool add_row = ProcessOneOpcode(reader_, handler_, header_,
+lineptr, &lsm, &oplength, (uintptr)-1,
+NULL);
+if (add_row) {
+if (have_pending_line)
+handler_->AddLine(pending_address, lsm.address - pending_address,
+pending_file_num, pending_line_num,
+pending_column_num);
+if (lsm.end_sequence) {
+lsm.Reset(header_.default_is_stmt);
+have_pending_line = false;
+} else {
+pending_address = lsm.address;
+pending_file_num = lsm.file_num;
+pending_line_num = lsm.line_num;
+pending_column_num = lsm.column_num;
+have_pending_line = true;
+}
+}
+lineptr += oplength;
+}
+after_header_ = lengthstart + header_.total_length;
+}
+// A DWARF rule for recovering the address or value of a register, or
+// computing the canonical frame address. There is one subclass of this for
+// each '*Rule' member function in CallFrameInfo::Handler.
+//
+// It's annoying that we have to handle Rules using pointers (because
+// the concrete instances can have an arbitrary size). They're small,
+// so it would be much nicer if we could just handle them by value
+// instead of fretting about ownership and destruction.
+//
+// It seems like all these could simply be instances of std::tr1::bind,
+// except that we need instances to be EqualityComparable, too.
+//
+// This could logically be nested within State, but then the qualified names
+// get horrendous.
+class CallFrameInfo::Rule {
+public:
+virtual ~Rule() { }
+// Tell HANDLER that, at ADDRESS in the program, REGISTER can be
+// recovered using this rule. If REGISTER is kCFARegister, then this rule
+// describes how to compute the canonical frame address. Return what the
+// HANDLER member function returned.
+virtual bool Handle(Handler *handler,
+uint64 address, int register) const = 0;
+// Equality on rules. We use these to decide which rules we need
+// to report after a DW_CFA_restore_state instruction.
+virtual bool operator==(const Rule &rhs) const = 0;
+bool operator!=(const Rule &rhs) const { return ! (*this == rhs); }
+// Return a pointer to a copy of this rule.
+virtual Rule *Copy() const = 0;
+// If this is a base+offset rule, change its base register to REG.
+// Otherwise, do nothing. (Ugly, but required for DW_CFA_def_cfa_register.)
+virtual void SetBaseRegister(unsigned reg) { }
+// If this is a base+offset rule, change its offset to OFFSET. Otherwise,
+// do nothing. (Ugly, but required for DW_CFA_def_cfa_offset.)
+virtual void SetOffset(long long offset) { }
+// A RTTI workaround, to make it possible to implement equality
+// comparisons on classes derived from this one.
+enum CFIRTag {
+CFIR_UNDEFINED_RULE,
+CFIR_SAME_VALUE_RULE,
+CFIR_OFFSET_RULE,
+CFIR_VAL_OFFSET_RULE,
+CFIR_REGISTER_RULE,
+CFIR_EXPRESSION_RULE,
+CFIR_VAL_EXPRESSION_RULE
+};
+// Produce the tag that identifies the child class of this object.
+virtual CFIRTag getTag() const = 0;
+};
+// Rule: the value the register had in the caller cannot be recovered.
+class CallFrameInfo::UndefinedRule: public CallFrameInfo::Rule {
+public:
+UndefinedRule() { }
+~UndefinedRule() { }
+CFIRTag getTag() const { return CFIR_UNDEFINED_RULE; }
+bool Handle(Handler *handler, uint64 address, int reg) const {
+return handler->UndefinedRule(address, reg);
+}
+bool operator==(const Rule &rhs) const {
+if (rhs.getTag() != CFIR_UNDEFINED_RULE) return false;
+return true;
+}
+Rule *Copy() const { return new UndefinedRule(*this); }
+};
+// Rule: the register's value is the same as that it had in the caller.
+class CallFrameInfo::SameValueRule: public CallFrameInfo::Rule {
+public:
+SameValueRule() { }
+~SameValueRule() { }
+CFIRTag getTag() const { return CFIR_SAME_VALUE_RULE; }
+bool Handle(Handler *handler, uint64 address, int reg) const {
+return handler->SameValueRule(address, reg);
+}
+bool operator==(const Rule &rhs) const {
+if (rhs.getTag() != CFIR_SAME_VALUE_RULE) return false;
+return true;
+}
+Rule *Copy() const { return new SameValueRule(*this); }
+};
+// Rule: the register is saved at OFFSET from BASE_REGISTER.  BASE_REGISTER
+// may be CallFrameInfo::Handler::kCFARegister.
+class CallFrameInfo::OffsetRule: public CallFrameInfo::Rule {
+public:
+OffsetRule(int base_register, long offset)
+: base_register_(base_register), offset_(offset) { }
+~OffsetRule() { }
+CFIRTag getTag() const { return CFIR_OFFSET_RULE; }
+bool Handle(Handler *handler, uint64 address, int reg) const {
+return handler->OffsetRule(address, reg, base_register_, offset_);
+}
+bool operator==(const Rule &rhs) const {
+if (rhs.getTag() != CFIR_OFFSET_RULE) return false;
+const OffsetRule *our_rhs = static_cast<const OffsetRule *>(&rhs);
+return (base_register_ == our_rhs->base_register_ &&
+offset_ == our_rhs->offset_);
+}
+Rule *Copy() const { return new OffsetRule(*this); }
+// We don't actually need SetBaseRegister or SetOffset here, since they
+// are only ever applied to CFA rules, for DW_CFA_def_cfa_offset, and it
+// doesn't make sense to use OffsetRule for computing the CFA: it
+// computes the address at which a register is saved, not a value.
+private:
+int base_register_;
+long offset_;
+};
+// Rule: the value the register had in the caller is the value of
+// BASE_REGISTER plus offset. BASE_REGISTER may be
+// CallFrameInfo::Handler::kCFARegister.
+class CallFrameInfo::ValOffsetRule: public CallFrameInfo::Rule {
+public:
+ValOffsetRule(int base_register, long offset)
+: base_register_(base_register), offset_(offset) { }
+~ValOffsetRule() { }
+CFIRTag getTag() const { return CFIR_VAL_OFFSET_RULE; }
+bool Handle(Handler *handler, uint64 address, int reg) const {
+return handler->ValOffsetRule(address, reg, base_register_, offset_);
+}
+bool operator==(const Rule &rhs) const {
+if (rhs.getTag() != CFIR_VAL_OFFSET_RULE) return false;
+const ValOffsetRule *our_rhs = static_cast<const ValOffsetRule *>(&rhs);
+return (base_register_ == our_rhs->base_register_ &&
+offset_ == our_rhs->offset_);
+}
+Rule *Copy() const { return new ValOffsetRule(*this); }
+void SetBaseRegister(unsigned reg) { base_register_ = reg; }
+void SetOffset(long long offset) { offset_ = offset; }
+private:
+int base_register_;
+long offset_;
+};
+// Rule: the register has been saved in another register REGISTER_NUMBER_.
+class CallFrameInfo::RegisterRule: public CallFrameInfo::Rule {
+public:
+explicit RegisterRule(int register_number)
+: register_number_(register_number) { }
+~RegisterRule() { }
+CFIRTag getTag() const { return CFIR_REGISTER_RULE; }
+bool Handle(Handler *handler, uint64 address, int reg) const {
+return handler->RegisterRule(address, reg, register_number_);
+}
+bool operator==(const Rule &rhs) const {
+if (rhs.getTag() != CFIR_REGISTER_RULE) return false;
+const RegisterRule *our_rhs = static_cast<const RegisterRule *>(&rhs);
+return (register_number_ == our_rhs->register_number_);
+}
+Rule *Copy() const { return new RegisterRule(*this); }
+private:
+int register_number_;
+};
+// Rule: EXPRESSION evaluates to the address at which the register is saved.
+class CallFrameInfo::ExpressionRule: public CallFrameInfo::Rule {
+public:
+explicit ExpressionRule(const string &expression)
+: expression_(expression) { }
+~ExpressionRule() { }
+CFIRTag getTag() const { return CFIR_EXPRESSION_RULE; }
+bool Handle(Handler *handler, uint64 address, int reg) const {
+return handler->ExpressionRule(address, reg, expression_);
+}
+bool operator==(const Rule &rhs) const {
+if (rhs.getTag() != CFIR_EXPRESSION_RULE) return false;
+const ExpressionRule *our_rhs = static_cast<const ExpressionRule *>(&rhs);
+return (expression_ == our_rhs->expression_);
+}
+Rule *Copy() const { return new ExpressionRule(*this); }
+private:
+string expression_;
+};
+// Rule: EXPRESSION evaluates to the address at which the register is saved.
+class CallFrameInfo::ValExpressionRule: public CallFrameInfo::Rule {
+public:
+explicit ValExpressionRule(const string &expression)
+: expression_(expression) { }
+~ValExpressionRule() { }
+CFIRTag getTag() const { return CFIR_VAL_EXPRESSION_RULE; }
+bool Handle(Handler *handler, uint64 address, int reg) const {
+return handler->ValExpressionRule(address, reg, expression_);
+}
+bool operator==(const Rule &rhs) const {
+if (rhs.getTag() != CFIR_VAL_EXPRESSION_RULE) return false;
+const ValExpressionRule *our_rhs =
+static_cast<const ValExpressionRule *>(&rhs);
+return (expression_ == our_rhs->expression_);
+}
+Rule *Copy() const { return new ValExpressionRule(*this); }
+private:
+string expression_;
+};
+// A map from register numbers to rules.
+class CallFrameInfo::RuleMap {
+public:
+RuleMap() : cfa_rule_(NULL) { }
+RuleMap(const RuleMap &rhs) : cfa_rule_(NULL) { *this = rhs; }
+~RuleMap() { Clear(); }
+RuleMap &operator=(const RuleMap &rhs);
+// Set the rule for computing the CFA to RULE. Take ownership of RULE.
+void SetCFARule(Rule *rule) { delete cfa_rule_; cfa_rule_ = rule; }
+// Return the current CFA rule. Unlike RegisterRule, this RuleMap retains
+// ownership of the rule. We use this for DW_CFA_def_cfa_offset and
+// DW_CFA_def_cfa_register, and for detecting references to the CFA before
+// a rule for it has been established.
+Rule *CFARule() const { return cfa_rule_; }
+// Return the rule for REG, or NULL if there is none. The caller takes
+// ownership of the result.
+Rule *RegisterRule(int reg) const;
+// Set the rule for computing REG to RULE. Take ownership of RULE.
+void SetRegisterRule(int reg, Rule *rule);
+// Make all the appropriate calls to HANDLER as if we were changing from
+// this RuleMap to NEW_RULES at ADDRESS. We use this to implement
+// DW_CFA_restore_state, where lots of rules can change simultaneously.
+// Return true if all handlers returned true; otherwise, return false.
+bool HandleTransitionTo(Handler *handler, uint64 address,
+const RuleMap &new_rules) const;
+private:
+// A map from register numbers to Rules.
+typedef std::map<int, Rule *> RuleByNumber;
+// Remove all register rules and clear cfa_rule_.
+void Clear();
+// The rule for computing the canonical frame address. This RuleMap owns
+// this rule.
+Rule *cfa_rule_;
+// A map from register numbers to postfix expressions to recover
+// their values. This RuleMap owns the Rules the map refers to.
+RuleByNumber registers_;
+};
+CallFrameInfo::RuleMap &CallFrameInfo::RuleMap::operator=(const RuleMap &rhs) {
+Clear();
+// Since each map owns the rules it refers to, assignment must copy them.
+if (rhs.cfa_rule_) cfa_rule_ = rhs.cfa_rule_->Copy();
+for (RuleByNumber::const_iterator it = rhs.registers_.begin();
+it != rhs.registers_.end(); it++)
+registers_[it->first] = it->second->Copy();
+return *this;
+}
+CallFrameInfo::Rule *CallFrameInfo::RuleMap::RegisterRule(int reg) const {
+assert(reg != Handler::kCFARegister);
+RuleByNumber::const_iterator it = registers_.find(reg);
+if (it != registers_.end())
+return it->second->Copy();
+else
+return NULL;
+}
+void CallFrameInfo::RuleMap::SetRegisterRule(int reg, Rule *rule) {
+assert(reg != Handler::kCFARegister);
+assert(rule);
+Rule **slot = &registers_[reg];
+delete *slot;
+*slot = rule;
+}
+bool CallFrameInfo::RuleMap::HandleTransitionTo(
+Handler *handler,
+uint64 address,
+const RuleMap &new_rules) const {
+// Transition from cfa_rule_ to new_rules.cfa_rule_.
+if (cfa_rule_ && new_rules.cfa_rule_) {
+if (*cfa_rule_ != *new_rules.cfa_rule_ &&
+!new_rules.cfa_rule_->Handle(handler, address,
+Handler::kCFARegister))
+return false;
+} else if (cfa_rule_) {
+// this RuleMap has a CFA rule but new_rules doesn't.
+// CallFrameInfo::Handler has no way to handle this --- and shouldn't;
+// it's garbage input. The instruction interpreter should have
+// detected this and warned, so take no action here.
+} else if (new_rules.cfa_rule_) {
+// This shouldn't be possible: NEW_RULES is some prior state, and
+// there's no way to remove entries.
+assert(0);
+} else {
+// Both CFA rules are empty.  No action needed.
+}
+// Traverse the two maps in order by register number, and report
+// whatever differences we find.
+RuleByNumber::const_iterator old_it = registers_.begin();
+RuleByNumber::const_iterator new_it = new_rules.registers_.begin();
+while (old_it != registers_.end() && new_it != new_rules.registers_.end()) {
+if (old_it->first < new_it->first) {
+// This RuleMap has an entry for old_it->first, but NEW_RULES
+// doesn't.
+//
+// This isn't really the right thing to do, but since CFI generally
+// only mentions callee-saves registers, and GCC's convention for
+// callee-saves registers is that they are unchanged, it's a good
+// approximation.
+if (!handler->SameValueRule(address, old_it->first))
+return false;
+old_it++;
+} else if (old_it->first > new_it->first) {
+// NEW_RULES has entry for new_it->first, but this RuleMap
+// doesn't. This shouldn't be possible: NEW_RULES is some prior
+// state, and there's no way to remove entries.
+assert(0);
+} else {
+// Both maps have an entry for this register. Report the new
+// rule if it is different.
+if (*old_it->second != *new_it->second &&
+!new_it->second->Handle(handler, address, new_it->first))
+return false;
+new_it++, old_it++;
+}
+}
+// Finish off entries from this RuleMap with no counterparts in new_rules.
+while (old_it != registers_.end()) {
+if (!handler->SameValueRule(address, old_it->first))
+return false;
+old_it++;
+}
+// Since we only make transitions from a rule set to some previously
+// saved rule set, and we can only add rules to the map, NEW_RULES
+// must have fewer rules than *this.
+assert(new_it == new_rules.registers_.end());
+return true;
+}
+// Remove all register rules and clear cfa_rule_.
+void CallFrameInfo::RuleMap::Clear() {
+delete cfa_rule_;
+cfa_rule_ = NULL;
+for (RuleByNumber::iterator it = registers_.begin();
+it != registers_.end(); it++)
+delete it->second;
+registers_.clear();
+}
+// The state of the call frame information interpreter as it processes
+// instructions from a CIE and FDE.
+class CallFrameInfo::State {
+public:
+// Create a call frame information interpreter state with the given
+// reporter, reader, handler, and initial call frame info address.
+State(ByteReader *reader, Handler *handler, Reporter *reporter,
+uint64 address)
+: reader_(reader), handler_(handler), reporter_(reporter),
+address_(address), entry_(NULL), cursor_(NULL) { }
+// Interpret instructions from CIE, save the resulting rule set for
+// DW_CFA_restore instructions, and return true. On error, report
+// the problem to reporter_ and return false.
+bool InterpretCIE(const CIE &cie);
+// Interpret instructions from FDE, and return true. On error,
+// report the problem to reporter_ and return false.
+bool InterpretFDE(const FDE &fde);
+private:
+// The operands of a CFI instruction, for ParseOperands.
+struct Operands {
+unsigned register_number;  // A register number.
+uint64 offset;             // An offset or address.
+long signed_offset;        // A signed offset.
+string expression;         // A DWARF expression.
+};
+// Parse CFI instruction operands from STATE's instruction stream as
+// described by FORMAT. On success, populate OPERANDS with the
+// results, and return true. On failure, report the problem and
+// return false.
+//
+// Each character of FORMAT should be one of the following:
+//
+//   'r'  unsigned LEB128 register number (OPERANDS->register_number)
+//   'o'  unsigned LEB128 offset          (OPERANDS->offset)
+//   's'  signed LEB128 offset            (OPERANDS->signed_offset)
+//   'a'  machine-size address            (OPERANDS->offset)
+//        (If the CIE has a 'z' augmentation string, 'a' uses the
+//        encoding specified by the 'R' argument.)
+//   '1'  a one-byte offset               (OPERANDS->offset)
+//   '2'  a two-byte offset               (OPERANDS->offset)
+//   '4'  a four-byte offset              (OPERANDS->offset)
+//   '8'  an eight-byte offset            (OPERANDS->offset)
+//   'e'  a DW_FORM_block holding a       (OPERANDS->expression)
+//        DWARF expression
+bool ParseOperands(const char *format, Operands *operands);
+// Interpret one CFI instruction from STATE's instruction stream, update
+// STATE, report any rule changes to handler_, and return true. On
+// failure, report the problem and return false.
+bool DoInstruction();
+// The following Do* member functions are subroutines of DoInstruction,
+// factoring out the actual work of operations that have several
+// different encodings.
+// Set the CFA rule to be the value of BASE_REGISTER plus OFFSET, and
+// return true. On failure, report and return false. (Used for
+// DW_CFA_def_cfa and DW_CFA_def_cfa_sf.)
+bool DoDefCFA(unsigned base_register, long offset);
+// Change the offset of the CFA rule to OFFSET, and return true. On
+// failure, report and return false. (Subroutine for
+// DW_CFA_def_cfa_offset and DW_CFA_def_cfa_offset_sf.)
+bool DoDefCFAOffset(long offset);
+// Specify that REG can be recovered using RULE, and return true. On
+// failure, report and return false.
+bool DoRule(unsigned reg, Rule *rule);
+// Specify that REG can be found at OFFSET from the CFA, and return true.
+// On failure, report and return false. (Subroutine for DW_CFA_offset,
+// DW_CFA_offset_extended, and DW_CFA_offset_extended_sf.)
+bool DoOffset(unsigned reg, long offset);
+// Specify that the caller's value for REG is the CFA plus OFFSET,
+// and return true. On failure, report and return false. (Subroutine
+// for DW_CFA_val_offset and DW_CFA_val_offset_sf.)
+bool DoValOffset(unsigned reg, long offset);
+// Restore REG to the rule established in the CIE, and return true. On
+// failure, report and return false. (Subroutine for DW_CFA_restore and
+// DW_CFA_restore_extended.)
+bool DoRestore(unsigned reg);
+// Return the section offset of the instruction at cursor. For use
+// in error messages.
+uint64 CursorOffset() { return entry_->offset + (cursor_ - entry_->start); }
+// Report that entry_ is incomplete, and return false. For brevity.
+bool ReportIncomplete() {
+reporter_->Incomplete(entry_->offset, entry_->kind);
+return false;
+}
+// For reading multi-byte values with the appropriate endianness.
+ByteReader *reader_;
+// The handler to which we should report the data we find.
+Handler *handler_;
+// For reporting problems in the info we're parsing.
+Reporter *reporter_;
+// The code address to which the next instruction in the stream applies.
+uint64 address_;
+// The entry whose instructions we are currently processing. This is
+// first a CIE, and then an FDE.
+const Entry *entry_;
+// The next instruction to process.
+const char *cursor_;
+// The current set of rules.
+RuleMap rules_;
+// The set of rules established by the CIE, used by DW_CFA_restore
+// and DW_CFA_restore_extended. We set this after interpreting the
+// CIE's instructions.
+RuleMap cie_rules_;
+// A stack of saved states, for DW_CFA_remember_state and
+// DW_CFA_restore_state.
+std::stack<RuleMap> saved_rules_;
+};
+bool CallFrameInfo::State::InterpretCIE(const CIE &cie) {
+entry_ = &cie;
+cursor_ = entry_->instructions;
+while (cursor_ < entry_->end)
+if (!DoInstruction())
+return false;
+// Note the rules established by the CIE, for use by DW_CFA_restore
+// and DW_CFA_restore_extended.
+cie_rules_ = rules_;
+return true;
+}
+bool CallFrameInfo::State::InterpretFDE(const FDE &fde) {
+entry_ = &fde;
+cursor_ = entry_->instructions;
+while (cursor_ < entry_->end)
+if (!DoInstruction())
+return false;
+return true;
+}
+bool CallFrameInfo::State::ParseOperands(const char *format,
+Operands *operands) {
+size_t len;
+const char *operand;
+for (operand = format; *operand; operand++) {
+size_t bytes_left = entry_->end - cursor_;
+switch (*operand) {
+case 'r':
+operands->register_number = reader_->ReadUnsignedLEB128(cursor_, &len);
+if (len > bytes_left) return ReportIncomplete();
+cursor_ += len;
+break;
+case 'o':
+operands->offset = reader_->ReadUnsignedLEB128(cursor_, &len);
+if (len > bytes_left) return ReportIncomplete();
+cursor_ += len;
+break;
+case 's':
+operands->signed_offset = reader_->ReadSignedLEB128(cursor_, &len);
+if (len > bytes_left) return ReportIncomplete();
+cursor_ += len;
+break;
+case 'a':
+operands->offset =
+reader_->ReadEncodedPointer(cursor_, entry_->cie->pointer_encoding,
+&len);
+if (len > bytes_left) return ReportIncomplete();
+cursor_ += len;
+break;
+case '1':
+if (1 > bytes_left) return ReportIncomplete();
+operands->offset = static_cast<unsigned char>(*cursor_++);
+break;
+case '2':
+if (2 > bytes_left) return ReportIncomplete();
+operands->offset = reader_->ReadTwoBytes(cursor_);
+cursor_ += 2;
+break;
+case '4':
+if (4 > bytes_left) return ReportIncomplete();
+operands->offset = reader_->ReadFourBytes(cursor_);
+cursor_ += 4;
+break;
+case '8':
+if (8 > bytes_left) return ReportIncomplete();
+operands->offset = reader_->ReadEightBytes(cursor_);
+cursor_ += 8;
+break;
+case 'e': {
+size_t expression_length = reader_->ReadUnsignedLEB128(cursor_, &len);
+if (len > bytes_left || expression_length > bytes_left - len)
+return ReportIncomplete();
+cursor_ += len;
+operands->expression = string(cursor_, expression_length);
+cursor_ += expression_length;
+break;
+}
+default:
+assert(0);
+}
+}
+return true;
+}
+bool CallFrameInfo::State::DoInstruction() {
+CIE *cie = entry_->cie;
+Operands ops;
+// Our entry's kind should have been set by now.
+assert(entry_->kind != kUnknown);
+// We shouldn't have been invoked unless there were more
+// instructions to parse.
+assert(cursor_ < entry_->end);
+unsigned opcode = *cursor_++;
+if ((opcode & 0xc0) != 0) {
+switch (opcode & 0xc0) {
+// Advance the address.
+case DW_CFA_advance_loc: {
+size_t code_offset = opcode & 0x3f;
+address_ += code_offset * cie->code_alignment_factor;
+break;
+}
+// Find a register at an offset from the CFA.
+case DW_CFA_offset:
+if (!ParseOperands("o", &ops) ||
+!DoOffset(opcode & 0x3f, ops.offset * cie->data_alignment_factor))
+return false;
+break;
+// Restore the rule established for a register by the CIE.
+case DW_CFA_restore:
+if (!DoRestore(opcode & 0x3f)) return false;
+break;
+// The 'if' above should have excluded this possibility.
+default:
+assert(0);
+}
+// Return here, so the big switch below won't be indented.
+return true;
+}
+switch (opcode) {
+// Set the address.
+case DW_CFA_set_loc:
+if (!ParseOperands("a", &ops)) return false;
+address_ = ops.offset;
+break;
+// Advance the address.
+case DW_CFA_advance_loc1:
+if (!ParseOperands("1", &ops)) return false;
+address_ += ops.offset * cie->code_alignment_factor;
+break;
+// Advance the address.
+case DW_CFA_advance_loc2:
+if (!ParseOperands("2", &ops)) return false;
+address_ += ops.offset * cie->code_alignment_factor;
+break;
+// Advance the address.
+case DW_CFA_advance_loc4:
+if (!ParseOperands("4", &ops)) return false;
+address_ += ops.offset * cie->code_alignment_factor;
+break;
+// Advance the address.
+case DW_CFA_MIPS_advance_loc8:
+if (!ParseOperands("8", &ops)) return false;
+address_ += ops.offset * cie->code_alignment_factor;
+break;
+// Compute the CFA by adding an offset to a register.
+case DW_CFA_def_cfa:
+if (!ParseOperands("ro", &ops) ||
+!DoDefCFA(ops.register_number, ops.offset))
+return false;
+break;
+// Compute the CFA by adding an offset to a register.
+case DW_CFA_def_cfa_sf:
+if (!ParseOperands("rs", &ops) ||
+!DoDefCFA(ops.register_number,
+ops.signed_offset * cie->data_alignment_factor))
+return false;
+break;
+// Change the base register used to compute the CFA.
+case DW_CFA_def_cfa_register: {
+Rule *cfa_rule = rules_.CFARule();
+if (!cfa_rule) {
+reporter_->NoCFARule(entry_->offset, entry_->kind, CursorOffset());
+return false;
+}
+if (!ParseOperands("r", &ops)) return false;
+cfa_rule->SetBaseRegister(ops.register_number);
+if (!cfa_rule->Handle(handler_, address_,
+Handler::kCFARegister))
+return false;
+break;
+}
+// Change the offset used to compute the CFA.
+case DW_CFA_def_cfa_offset:
+if (!ParseOperands("o", &ops) ||
+!DoDefCFAOffset(ops.offset))
+return false;
+break;
+// Change the offset used to compute the CFA.
+case DW_CFA_def_cfa_offset_sf:
+if (!ParseOperands("s", &ops) ||
+!DoDefCFAOffset(ops.signed_offset * cie->data_alignment_factor))
+return false;
+break;
+// Specify an expression whose value is the CFA.
+case DW_CFA_def_cfa_expression: {
+if (!ParseOperands("e", &ops))
+return false;
+Rule *rule = new ValExpressionRule(ops.expression);
+rules_.SetCFARule(rule);
+if (!rule->Handle(handler_, address_,
+Handler::kCFARegister))
+return false;
+break;
+}
+// The register's value cannot be recovered.
+case DW_CFA_undefined: {
+if (!ParseOperands("r", &ops) ||
+!DoRule(ops.register_number, new UndefinedRule()))
+return false;
+break;
+}
+// The register's value is unchanged from its value in the caller.
+case DW_CFA_same_value: {
+if (!ParseOperands("r", &ops) ||
+!DoRule(ops.register_number, new SameValueRule()))
+return false;
+break;
+}
+// Find a register at an offset from the CFA.
+case DW_CFA_offset_extended:
+if (!ParseOperands("ro", &ops) ||
+!DoOffset(ops.register_number,
+ops.offset * cie->data_alignment_factor))
+return false;
+break;
+// The register is saved at an offset from the CFA.
+case DW_CFA_offset_extended_sf:
+if (!ParseOperands("rs", &ops) ||
+!DoOffset(ops.register_number,
+ops.signed_offset * cie->data_alignment_factor))
+return false;
+break;
+// The register is saved at an offset from the CFA.
+case DW_CFA_GNU_negative_offset_extended:
+if (!ParseOperands("ro", &ops) ||
+!DoOffset(ops.register_number,
+-ops.offset * cie->data_alignment_factor))
+return false;
+break;
+// The register's value is the sum of the CFA plus an offset.
+case DW_CFA_val_offset:
+if (!ParseOperands("ro", &ops) ||
+!DoValOffset(ops.register_number,
+ops.offset * cie->data_alignment_factor))
+return false;
+break;
+// The register's value is the sum of the CFA plus an offset.
+case DW_CFA_val_offset_sf:
+if (!ParseOperands("rs", &ops) ||
+!DoValOffset(ops.register_number,
+ops.signed_offset * cie->data_alignment_factor))
+return false;
+break;
+// The register has been saved in another register.
+case DW_CFA_register: {
+if (!ParseOperands("ro", &ops) ||
+!DoRule(ops.register_number, new RegisterRule(ops.offset)))
+return false;
+break;
+}
+// An expression yields the address at which the register is saved.
+case DW_CFA_expression: {
+if (!ParseOperands("re", &ops) ||
+!DoRule(ops.register_number, new ExpressionRule(ops.expression)))
+return false;
+break;
+}
+// An expression yields the caller's value for the register.
+case DW_CFA_val_expression: {
+if (!ParseOperands("re", &ops) ||
+!DoRule(ops.register_number, new ValExpressionRule(ops.expression)))
+return false;
+break;
+}
+// Restore the rule established for a register by the CIE.
+case DW_CFA_restore_extended:
+if (!ParseOperands("r", &ops) ||
+!DoRestore( ops.register_number))
+return false;
+break;
+// Save the current set of rules on a stack.
+case DW_CFA_remember_state:
+saved_rules_.push(rules_);
+break;
+// Pop the current set of rules off the stack.
+case DW_CFA_restore_state: {
+if (saved_rules_.empty()) {
+reporter_->EmptyStateStack(entry_->offset, entry_->kind,
+CursorOffset());
+return false;
+}
+const RuleMap &new_rules = saved_rules_.top();
+if (rules_.CFARule() && !new_rules.CFARule()) {
+reporter_->ClearingCFARule(entry_->offset, entry_->kind,
+CursorOffset());
+return false;
+}
+rules_.HandleTransitionTo(handler_, address_, new_rules);
+rules_ = new_rules;
+saved_rules_.pop();
+break;
+}
+// No operation.  (Padding instruction.)
+case DW_CFA_nop:
+break;
+// A SPARC register window save: Registers 8 through 15 (%o0-%o7)
+// are saved in registers 24 through 31 (%i0-%i7), and registers
+// 16 through 31 (%l0-%l7 and %i0-%i7) are saved at CFA offsets
+// (0-15 * the register size). The register numbers must be
+// hard-coded. A GNU extension, and not a pretty one.
+case DW_CFA_GNU_window_save: {
+// Save %o0-%o7 in %i0-%i7.
+for (int i = 8; i < 16; i++)
+if (!DoRule(i, new RegisterRule(i + 16)))
+return false;
+// Save %l0-%l7 and %i0-%i7 at the CFA.
+for (int i = 16; i < 32; i++)
+// Assume that the byte reader's address size is the same as
+// the architecture's register size. !@#%*^ hilarious.
+if (!DoRule(i, new OffsetRule(Handler::kCFARegister,
+(i - 16) * reader_->AddressSize())))
+return false;
+break;
+}
+// I'm not sure what this is. GDB doesn't use it for unwinding.
+case DW_CFA_GNU_args_size:
+if (!ParseOperands("o", &ops)) return false;
+break;
+// An opcode we don't recognize.
+default: {
+reporter_->BadInstruction(entry_->offset, entry_->kind, CursorOffset());
+return false;
+}
+}
+return true;
+}
+bool CallFrameInfo::State::DoDefCFA(unsigned base_register, long offset) {
+Rule *rule = new ValOffsetRule(base_register, offset);
+rules_.SetCFARule(rule);
+return rule->Handle(handler_, address_,
+Handler::kCFARegister);
+}
+bool CallFrameInfo::State::DoDefCFAOffset(long offset) {
+Rule *cfa_rule = rules_.CFARule();
+if (!cfa_rule) {
+reporter_->NoCFARule(entry_->offset, entry_->kind, CursorOffset());
+return false;
+}
+cfa_rule->SetOffset(offset);
+return cfa_rule->Handle(handler_, address_,
+Handler::kCFARegister);
+}
+bool CallFrameInfo::State::DoRule(unsigned reg, Rule *rule) {
+rules_.SetRegisterRule(reg, rule);
+return rule->Handle(handler_, address_, reg);
+}
+bool CallFrameInfo::State::DoOffset(unsigned reg, long offset) {
+if (!rules_.CFARule()) {
+reporter_->NoCFARule(entry_->offset, entry_->kind, CursorOffset());
+return false;
+}
+return DoRule(reg,
+new OffsetRule(Handler::kCFARegister, offset));
+}
+bool CallFrameInfo::State::DoValOffset(unsigned reg, long offset) {
+if (!rules_.CFARule()) {
+reporter_->NoCFARule(entry_->offset, entry_->kind, CursorOffset());
+return false;
+}
+return DoRule(reg,
+new ValOffsetRule(Handler::kCFARegister, offset));
+}
+bool CallFrameInfo::State::DoRestore(unsigned reg) {
+// DW_CFA_restore and DW_CFA_restore_extended don't make sense in a CIE.
+if (entry_->kind == kCIE) {
+reporter_->RestoreInCIE(entry_->offset, CursorOffset());
+return false;
+}
+Rule *rule = cie_rules_.RegisterRule(reg);
+if (!rule) {
+// This isn't really the right thing to do, but since CFI generally
+// only mentions callee-saves registers, and GCC's convention for
+// callee-saves registers is that they are unchanged, it's a good
+// approximation.
+rule = new SameValueRule();
+}
+return DoRule(reg, rule);
+}
+bool CallFrameInfo::ReadEntryPrologue(const char *cursor, Entry *entry) {
+const char *buffer_end = buffer_ + buffer_length_;
+// Initialize enough of ENTRY for use in error reporting.
+entry->offset = cursor - buffer_;
+entry->start = cursor;
+entry->kind = kUnknown;
+entry->end = NULL;
+// Read the initial length. This sets reader_'s offset size.
+size_t length_size;
+uint64 length = reader_->ReadInitialLength(cursor, &length_size);
+if (length_size > size_t(buffer_end - cursor))
+return ReportIncomplete(entry);
+cursor += length_size;
+// In a .eh_frame section, a length of zero marks the end of the series
+// of entries.
+if (length == 0 && eh_frame_) {
+entry->kind = kTerminator;
+entry->end = cursor;
+return true;
+}
+// Validate the length.
+if (length > size_t(buffer_end - cursor))
+return ReportIncomplete(entry);
+// The length is the number of bytes after the initial length field;
+// we have that position handy at this point, so compute the end
+// now. (If we're parsing 64-bit-offset DWARF on a 32-bit machine,
+// and the length didn't fit in a size_t, we would have rejected it
+// above.)
+entry->end = cursor + length;
+// Parse the next field: either the offset of a CIE or a CIE id.
+size_t offset_size = reader_->OffsetSize();
+if (offset_size > size_t(entry->end - cursor)) return ReportIncomplete(entry);
+entry->id = reader_->ReadOffset(cursor);
+// Don't advance cursor past id field yet; in .eh_frame data we need
+// the id's position to compute the section offset of an FDE's CIE.
+// Now we can decide what kind of entry this is.
+if (eh_frame_) {
+// In .eh_frame data, an ID of zero marks the entry as a CIE, and
+// anything else is an offset from the id field of the FDE to the start
+// of the CIE.
+if (entry->id == 0) {
+entry->kind = kCIE;
+} else {
+entry->kind = kFDE;
+// Turn the offset from the id into an offset from the buffer's start.
+entry->id = (cursor - buffer_) - entry->id;
+}
+} else {
+// In DWARF CFI data, an ID of ~0 (of the appropriate width, given the
+// offset size for the entry) marks the entry as a CIE, and anything
+// else is the offset of the CIE from the beginning of the section.
+if (offset_size == 4)
+entry->kind = (entry->id == 0xffffffff) ? kCIE : kFDE;
+else {
+assert(offset_size == 8);
+entry->kind = (entry->id == 0xffffffffffffffffULL) ? kCIE : kFDE;
+}
+}
+// Now advance cursor past the id.
+cursor += offset_size;
+// The fields specific to this kind of entry start here.
+entry->fields = cursor;
+entry->cie = NULL;
+return true;
+}
+bool CallFrameInfo::ReadCIEFields(CIE *cie) {
+const char *cursor = cie->fields;
+size_t len;
+assert(cie->kind == kCIE);
+// Prepare for early exit.
+cie->version = 0;
+cie->augmentation.clear();
+cie->code_alignment_factor = 0;
+cie->data_alignment_factor = 0;
+cie->return_address_register = 0;
+cie->has_z_augmentation = false;
+cie->pointer_encoding = DW_EH_PE_absptr;
+cie->instructions = 0;
+// Parse the version number.
+if (cie->end - cursor < 1)
+return ReportIncomplete(cie);
+cie->version = reader_->ReadOneByte(cursor);
+cursor++;
+// If we don't recognize the version, we can't parse any more fields of the
+// CIE. For DWARF CFI, we handle versions 1 through 3 (there was never a
+// version 2 of CFI data). For .eh_frame, we handle versions 1 and 3 as well;
+// the difference between those versions seems to be the same as for
+// .debug_frame.
+if (cie->version < 1 || cie->version > 3) {
+reporter_->UnrecognizedVersion(cie->offset, cie->version);
+return false;
+}
+const char *augmentation_start = cursor;
+const void *augmentation_end =
+memchr(augmentation_start, '\0', cie->end - augmentation_start);
+if (! augmentation_end) return ReportIncomplete(cie);
+cursor = static_cast<const char *>(augmentation_end);
+cie->augmentation = string(augmentation_start,
+cursor - augmentation_start);
+// Skip the terminating '\0'.
+cursor++;
+// Is this CFI augmented?
+if (!cie->augmentation.empty()) {
+// Is it an augmentation we recognize?
+if (cie->augmentation[0] == DW_Z_augmentation_start) {
+// Linux C++ ABI 'z' augmentation, used for exception handling data.
+cie->has_z_augmentation = true;
+} else {
+// Not an augmentation we recognize. Augmentations can have arbitrary
+// effects on the form of rest of the content, so we have to give up.
+reporter_->UnrecognizedAugmentation(cie->offset, cie->augmentation);
+return false;
+}
+}
+// Parse the code alignment factor.
+cie->code_alignment_factor = reader_->ReadUnsignedLEB128(cursor, &len);
+if (size_t(cie->end - cursor) < len) return ReportIncomplete(cie);
+cursor += len;
+// Parse the data alignment factor.
+cie->data_alignment_factor = reader_->ReadSignedLEB128(cursor, &len);
+if (size_t(cie->end - cursor) < len) return ReportIncomplete(cie);
+cursor += len;
+// Parse the return address register. This is a ubyte in version 1, and
+// a ULEB128 in version 3.
+if (cie->version == 1) {
+if (cursor >= cie->end) return ReportIncomplete(cie);
+cie->return_address_register = uint8(*cursor++);
+} else {
+cie->return_address_register = reader_->ReadUnsignedLEB128(cursor, &len);
+if (size_t(cie->end - cursor) < len) return ReportIncomplete(cie);
+cursor += len;
+}
+// If we have a 'z' augmentation string, find the augmentation data and
+// use the augmentation string to parse it.
+if (cie->has_z_augmentation) {
+uint64_t data_size = reader_->ReadUnsignedLEB128(cursor, &len);
+if (size_t(cie->end - cursor) < len + data_size)
+return ReportIncomplete(cie);
+cursor += len;
+const char *data = cursor;
+cursor += data_size;
+const char *data_end = cursor;
+cie->has_z_lsda = false;
+cie->has_z_personality = false;
+cie->has_z_signal_frame = false;
+// Walk the augmentation string, and extract values from the
+// augmentation data as the string directs.
+for (size_t i = 1; i < cie->augmentation.size(); i++) {
+switch (cie->augmentation[i]) {
+case DW_Z_has_LSDA:
+// The CIE's augmentation data holds the language-specific data
+// area pointer's encoding, and the FDE's augmentation data holds
+// the pointer itself.
+cie->has_z_lsda = true;
+// Fetch the LSDA encoding from the augmentation data.
+if (data >= data_end) return ReportIncomplete(cie);
+cie->lsda_encoding = DwarfPointerEncoding(*data++);
+if (!reader_->ValidEncoding(cie->lsda_encoding)) {
+reporter_->InvalidPointerEncoding(cie->offset, cie->lsda_encoding);
+return false;
+}
+// Don't check if the encoding is usable here --- we haven't
+// read the FDE's fields yet, so we're not prepared for
+// DW_EH_PE_funcrel, although that's a fine encoding for the
+// LSDA to use, since it appears in the FDE.
+break;
+case DW_Z_has_personality_routine:
+// The CIE's augmentation data holds the personality routine
+// pointer's encoding, followed by the pointer itself.
+cie->has_z_personality = true;
+// Fetch the personality routine pointer's encoding from the
+// augmentation data.
+if (data >= data_end) return ReportIncomplete(cie);
+cie->personality_encoding = DwarfPointerEncoding(*data++);
+if (!reader_->ValidEncoding(cie->personality_encoding)) {
+reporter_->InvalidPointerEncoding(cie->offset,
+cie->personality_encoding);
+return false;
+}
+if (!reader_->UsableEncoding(cie->personality_encoding)) {
+reporter_->UnusablePointerEncoding(cie->offset,
+cie->personality_encoding);
+return false;
+}
+// Fetch the personality routine's pointer itself from the data.
+cie->personality_address =
+reader_->ReadEncodedPointer(data, cie->personality_encoding,
+&len);
+if (len > size_t(data_end - data))
+return ReportIncomplete(cie);
+data += len;
+break;
+case DW_Z_has_FDE_address_encoding:
+// The CIE's augmentation data holds the pointer encoding to use
+// for addresses in the FDE.
+if (data >= data_end) return ReportIncomplete(cie);
+cie->pointer_encoding = DwarfPointerEncoding(*data++);
+if (!reader_->ValidEncoding(cie->pointer_encoding)) {
+reporter_->InvalidPointerEncoding(cie->offset,
+cie->pointer_encoding);
+return false;
+}
+if (!reader_->UsableEncoding(cie->pointer_encoding)) {
+reporter_->UnusablePointerEncoding(cie->offset,
+cie->pointer_encoding);
+return false;
+}
+break;
+case DW_Z_is_signal_trampoline:
+// Frames using this CIE are signal delivery frames.
+cie->has_z_signal_frame = true;
+break;
+default:
+// An augmentation we don't recognize.
+reporter_->UnrecognizedAugmentation(cie->offset, cie->augmentation);
+return false;
+}
+}
+}
+// The CIE's instructions start here.
+cie->instructions = cursor;
+return true;
+}
+bool CallFrameInfo::ReadFDEFields(FDE *fde) {
+const char *cursor = fde->fields;
+size_t size;
+fde->address = reader_->ReadEncodedPointer(cursor, fde->cie->pointer_encoding,
+&size);
+if (size > size_t(fde->end - cursor))
+return ReportIncomplete(fde);
+cursor += size;
+reader_->SetFunctionBase(fde->address);
+// For the length, we strip off the upper nybble of the encoding used for
+// the starting address.
+DwarfPointerEncoding length_encoding =
+DwarfPointerEncoding(fde->cie->pointer_encoding & 0x0f);
+fde->size = reader_->ReadEncodedPointer(cursor, length_encoding, &size);
+if (size > size_t(fde->end - cursor))
+return ReportIncomplete(fde);
+cursor += size;
+// If the CIE has a 'z' augmentation string, then augmentation data
+// appears here.
+if (fde->cie->has_z_augmentation) {
+uint64_t data_size = reader_->ReadUnsignedLEB128(cursor, &size);
+if (size_t(fde->end - cursor) < size + data_size)
+return ReportIncomplete(fde);
+cursor += size;
+// In the abstract, we should walk the augmentation string, and extract
+// items from the FDE's augmentation data as we encounter augmentation
+// string characters that specify their presence: the ordering of items
+// in the augmentation string determines the arrangement of values in
+// the augmentation data.
+//
+// In practice, there's only ever one value in FDE augmentation data
+// that we support --- the LSDA pointer --- and we have to bail if we
+// see any unrecognized augmentation string characters. So if there is
+// anything here at all, we know what it is, and where it starts.
+if (fde->cie->has_z_lsda) {
+// Check whether the LSDA's pointer encoding is usable now: only once
+// we've parsed the FDE's starting address do we call reader_->
+// SetFunctionBase, so that the DW_EH_PE_funcrel encoding becomes
+// usable.
+if (!reader_->UsableEncoding(fde->cie->lsda_encoding)) {
+reporter_->UnusablePointerEncoding(fde->cie->offset,
+fde->cie->lsda_encoding);
+return false;
+}
+fde->lsda_address =
+reader_->ReadEncodedPointer(cursor, fde->cie->lsda_encoding, &size);
+if (size > data_size)
+return ReportIncomplete(fde);
+// Ideally, we would also complain here if there were unconsumed
+// augmentation data.
+}
+cursor += data_size;
+}
+// The FDE's instructions start after those.
+fde->instructions = cursor;
+return true;
+}
+bool CallFrameInfo::Start() {
+const char *buffer_end = buffer_ + buffer_length_;
+const char *cursor;
+bool all_ok = true;
+const char *entry_end;
+bool ok;
+// Traverse all the entries in buffer_, skipping CIEs and offering
+// FDEs to the handler.
+for (cursor = buffer_; cursor < buffer_end;
+cursor = entry_end, all_ok = all_ok && ok) {
+FDE fde;
+// Make it easy to skip this entry with 'continue': assume that
+// things are not okay until we've checked all the data, and
+// prepare the address of the next entry.
+ok = false;
+// Read the entry's prologue.
+if (!ReadEntryPrologue(cursor, &fde)) {
+if (!fde.end) {
+// If we couldn't even figure out this entry's extent, then we
+// must stop processing entries altogether.
+all_ok = false;
+break;
+}
+entry_end = fde.end;
+continue;
+}
+// The next iteration picks up after this entry.
+entry_end = fde.end;
+// Did we see an .eh_frame terminating mark?
+if (fde.kind == kTerminator) {
+// If there appears to be more data left in the section after the
+// terminating mark, warn the user. But this is just a warning;
+// we leave all_ok true.
+if (fde.end < buffer_end) reporter_->EarlyEHTerminator(fde.offset);
+break;
+}
+// In this loop, we skip CIEs. We only parse them fully when we
+// parse an FDE that refers to them. This limits our memory
+// consumption (beyond the buffer itself) to that needed to
+// process the largest single entry.
+if (fde.kind != kFDE) {
+ok = true;
+continue;
+}
+// Validate the CIE pointer.
+if (fde.id > buffer_length_) {
+reporter_->CIEPointerOutOfRange(fde.offset, fde.id);
+continue;
+}
+CIE cie;
+// Parse this FDE's CIE header.
+if (!ReadEntryPrologue(buffer_ + fde.id, &cie))
+continue;
+// This had better be an actual CIE.
+if (cie.kind != kCIE) {
+reporter_->BadCIEId(fde.offset, fde.id);
+continue;
+}
+if (!ReadCIEFields(&cie))
+continue;
+// We now have the values that govern both the CIE and the FDE.
+cie.cie = &cie;
+fde.cie = &cie;
+// Parse the FDE's header.
+if (!ReadFDEFields(&fde))
+continue;
+// Call Entry to ask the consumer if they're interested.
+if (!handler_->Entry(fde.offset, fde.address, fde.size,
+cie.version, cie.augmentation,
+cie.return_address_register)) {
+// The handler isn't interested in this entry. That's not an error.
+ok = true;
+continue;
+}
+if (cie.has_z_augmentation) {
+// Report the personality routine address, if we have one.
+if (cie.has_z_personality) {
+if (!handler_
+->PersonalityRoutine(cie.personality_address,
+IsIndirectEncoding(cie.personality_encoding)))
+continue;
+}
+// Report the language-specific data area address, if we have one.
+if (cie.has_z_lsda) {
+if (!handler_
+->LanguageSpecificDataArea(fde.lsda_address,
+IsIndirectEncoding(cie.lsda_encoding)))
+continue;
+}
+// If this is a signal-handling frame, report that.
+if (cie.has_z_signal_frame) {
+if (!handler_->SignalHandler())
+continue;
+}
+}
+// Interpret the CIE's instructions, and then the FDE's instructions.
+State state(reader_, handler_, reporter_, fde.address);
+ok = state.InterpretCIE(cie) && state.InterpretFDE(fde);
+// Tell the ByteReader that the function start address from the
+// FDE header is no longer valid.
+reader_->ClearFunctionBase();
+// Report the end of the entry.
+handler_->End();
+}
+return all_ok;
+}
+const char *CallFrameInfo::KindName(EntryKind kind) {
+if (kind == CallFrameInfo::kUnknown)
+return "entry";
+else if (kind == CallFrameInfo::kCIE)
+return "common information entry";
+else if (kind == CallFrameInfo::kFDE)
+return "frame description entry";
+else {
+assert (kind == CallFrameInfo::kTerminator);
+return ".eh_frame sequence terminator";
+}
+}
+bool CallFrameInfo::ReportIncomplete(Entry *entry) {
+reporter_->Incomplete(entry->offset, entry->kind);
+return false;
+}
+void CallFrameInfo::Reporter::Incomplete(uint64 offset,
+CallFrameInfo::EntryKind kind) {
+fprintf(stderr,
+"%s: CFI %s at offset 0x%llx in '%s': entry ends early\n",
+filename_.c_str(), CallFrameInfo::KindName(kind), offset,
+section_.c_str());
+}
+void CallFrameInfo::Reporter::EarlyEHTerminator(uint64 offset) {
+fprintf(stderr,
+"%s: CFI at offset 0x%llx in '%s': saw end-of-data marker"
+" before end of section contents\n",
+filename_.c_str(), offset, section_.c_str());
+}
+void CallFrameInfo::Reporter::CIEPointerOutOfRange(uint64 offset,
+uint64 cie_offset) {
+fprintf(stderr,
+"%s: CFI frame description entry at offset 0x%llx in '%s':"
+" CIE pointer is out of range: 0x%llx\n",
+filename_.c_str(), offset, section_.c_str(), cie_offset);
+}
+void CallFrameInfo::Reporter::BadCIEId(uint64 offset, uint64 cie_offset) {
+fprintf(stderr,
+"%s: CFI frame description entry at offset 0x%llx in '%s':"
+" CIE pointer does not point to a CIE: 0x%llx\n",
+filename_.c_str(), offset, section_.c_str(), cie_offset);
+}
+void CallFrameInfo::Reporter::UnrecognizedVersion(uint64 offset, int version) {
+fprintf(stderr,
+"%s: CFI frame description entry at offset 0x%llx in '%s':"
+" CIE specifies unrecognized version: %d\n",
+filename_.c_str(), offset, section_.c_str(), version);
+}
+void CallFrameInfo::Reporter::UnrecognizedAugmentation(uint64 offset,
+const string &aug) {
+fprintf(stderr,
+"%s: CFI frame description entry at offset 0x%llx in '%s':"
+" CIE specifies unrecognized augmentation: '%s'\n",
+filename_.c_str(), offset, section_.c_str(), aug.c_str());
+}
+void CallFrameInfo::Reporter::InvalidPointerEncoding(uint64 offset,
+uint8 encoding) {
+fprintf(stderr,
+"%s: CFI common information entry at offset 0x%llx in '%s':"
+" 'z' augmentation specifies invalid pointer encoding: 0x%02x\n",
+filename_.c_str(), offset, section_.c_str(), encoding);
+}
+void CallFrameInfo::Reporter::UnusablePointerEncoding(uint64 offset,
+uint8 encoding) {
+fprintf(stderr,
+"%s: CFI common information entry at offset 0x%llx in '%s':"
+" 'z' augmentation specifies a pointer encoding for which"
+" we have no base address: 0x%02x\n",
+filename_.c_str(), offset, section_.c_str(), encoding);
+}
+void CallFrameInfo::Reporter::RestoreInCIE(uint64 offset, uint64 insn_offset) {
+fprintf(stderr,
+"%s: CFI common information entry at offset 0x%llx in '%s':"
+" the DW_CFA_restore instruction at offset 0x%llx"
+" cannot be used in a common information entry\n",
+filename_.c_str(), offset, section_.c_str(), insn_offset);
+}
+void CallFrameInfo::Reporter::BadInstruction(uint64 offset,
+CallFrameInfo::EntryKind kind,
+uint64 insn_offset) {
+fprintf(stderr,
+"%s: CFI %s at offset 0x%llx in section '%s':"
+" the instruction at offset 0x%llx is unrecognized\n",
+filename_.c_str(), CallFrameInfo::KindName(kind),
+offset, section_.c_str(), insn_offset);
+}
+void CallFrameInfo::Reporter::NoCFARule(uint64 offset,
+CallFrameInfo::EntryKind kind,
+uint64 insn_offset) {
+fprintf(stderr,
+"%s: CFI %s at offset 0x%llx in section '%s':"
+" the instruction at offset 0x%llx assumes that a CFA rule has"
+" been set, but none has been set\n",
+filename_.c_str(), CallFrameInfo::KindName(kind), offset,
+section_.c_str(), insn_offset);
+}
+void CallFrameInfo::Reporter::EmptyStateStack(uint64 offset,
+CallFrameInfo::EntryKind kind,
+uint64 insn_offset) {
+fprintf(stderr,
+"%s: CFI %s at offset 0x%llx in section '%s':"
+" the DW_CFA_restore_state instruction at offset 0x%llx"
+" should pop a saved state from the stack, but the stack is empty\n",
+filename_.c_str(), CallFrameInfo::KindName(kind), offset,
+section_.c_str(), insn_offset);
+}
+void CallFrameInfo::Reporter::ClearingCFARule(uint64 offset,
+CallFrameInfo::EntryKind kind,
+uint64 insn_offset) {
+fprintf(stderr,
+"%s: CFI %s at offset 0x%llx in section '%s':"
+" the DW_CFA_restore_state instruction at offset 0x%llx"
+" would clear the CFA rule in effect\n",
+filename_.c_str(), CallFrameInfo::KindName(kind), offset,
+section_.c_str(), insn_offset);
+}
+}  // namespace dwarf2reader

The Tor Browser / file comparison

comparison: toolkit/crashreporter/google-breakpad/src/common/dwarf/dwarf2reader.cc

toolkit/crashreporter/google-breakpad/src/common/dwarf/dwarf2reader.cc