// Copyright 2006 Google LLC
//
// 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 LLC 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.
#ifdef HAVE_CONFIG_H
#include <config.h> // Must come first
#endif
#include "common/windows/pdb_source_line_writer.h"
#include <windows.h>
#include <winnt.h>
#include <atlbase.h>
#include <dia2.h>
#include <diacreate.h>
#include <ImageHlp.h>
#include <stdio.h>
#include <algorithm>
#include <limits>
#include <map>
#include <memory>
#include <set>
#include <utility>
#include "common/windows/dia_util.h"
#include "common/windows/guid_string.h"
#include "common/windows/pe_util.h"
#include "common/windows/string_utils-inl.h"
// This constant may be missing from DbgHelp.h. See the documentation for
// IDiaSymbol::get_undecoratedNameEx.
#ifndef UNDNAME_NO_ECSU
#define UNDNAME_NO_ECSU 0x8000 // Suppresses enum/class/struct/union.
#endif // UNDNAME_NO_ECSU
namespace google_breakpad {
namespace {
using std::set;
using std::unique_ptr;
using std::vector;
// The symbol (among possibly many) selected to represent an rva.
struct SelectedSymbol {
SelectedSymbol(const CComPtr<IDiaSymbol>& symbol, bool is_public)
: symbol(symbol), is_public(is_public), is_multiple(false) {}
// The symbol to use for an rva.
CComPtr<IDiaSymbol> symbol;
// Whether this is a public or function symbol.
bool is_public;
// Whether the rva has multiple associated symbols. An rva will correspond to
// multiple symbols in the case of linker identical symbol folding.
bool is_multiple;
};
// Maps rva to the symbol to use for that address.
typedef std::map<DWORD, SelectedSymbol> SymbolMap;
// Record this in the map as the selected symbol for the rva if it satisfies the
// necessary conditions.
void MaybeRecordSymbol(DWORD rva,
const CComPtr<IDiaSymbol> symbol,
bool is_public,
SymbolMap* map) {
SymbolMap::iterator loc = map->find(rva);
if (loc == map->end()) {
map->insert(std::make_pair(rva, SelectedSymbol(symbol, is_public)));
return;
}
// Prefer function symbols to public symbols.
if (is_public && !loc->second.is_public) {
return;
}
loc->second.is_multiple = true;
// Take the 'least' symbol by lexicographical order of the decorated name. We
// use the decorated rather than undecorated name because computing the latter
// is expensive.
BSTR current_name, new_name;
loc->second.symbol->get_name(¤t_name);
symbol->get_name(&new_name);
if (wcscmp(new_name, current_name) < 0) {
loc->second.symbol = symbol;
loc->second.is_public = is_public;
}
}
bool SymbolsMatch(IDiaSymbol* a, IDiaSymbol* b) {
DWORD a_section, a_offset, b_section, b_offset;
if (FAILED(a->get_addressSection(&a_section)) ||
FAILED(a->get_addressOffset(&a_offset)) ||
FAILED(b->get_addressSection(&b_section)) ||
FAILED(b->get_addressOffset(&b_offset)))
return false;
return a_section == b_section && a_offset == b_offset;
}
bool CreateDiaDataSourceInstance(CComPtr<IDiaDataSource>& data_source) {
if (SUCCEEDED(data_source.CoCreateInstance(CLSID_DiaSource))) {
return true;
}
class DECLSPEC_UUID("B86AE24D-BF2F-4ac9-B5A2-34B14E4CE11D") DiaSource100;
class DECLSPEC_UUID("761D3BCD-1304-41D5-94E8-EAC54E4AC172") DiaSource110;
class DECLSPEC_UUID("3BFCEA48-620F-4B6B-81F7-B9AF75454C7D") DiaSource120;
class DECLSPEC_UUID("E6756135-1E65-4D17-8576-610761398C3C") DiaSource140;
// If the CoCreateInstance call above failed, msdia*.dll is not registered.
// We can try loading the DLL corresponding to the #included DIA SDK, but
// the DIA headers don't provide a version. Lets try to figure out which DIA
// version we're compiling against by comparing CLSIDs.
const wchar_t* msdia_dll = nullptr;
if (CLSID_DiaSource == _uuidof(DiaSource100)) {
msdia_dll = L"msdia100.dll";
} else if (CLSID_DiaSource == _uuidof(DiaSource110)) {
msdia_dll = L"msdia110.dll";
} else if (CLSID_DiaSource == _uuidof(DiaSource120)) {
msdia_dll = L"msdia120.dll";
} else if (CLSID_DiaSource == _uuidof(DiaSource140)) {
msdia_dll = L"msdia140.dll";
}
if (msdia_dll &&
SUCCEEDED(NoRegCoCreate(msdia_dll, CLSID_DiaSource, IID_IDiaDataSource,
reinterpret_cast<void**>(&data_source)))) {
return true;
}
return false;
}
const DWORD kUndecorateOptions = UNDNAME_NO_MS_KEYWORDS |
UNDNAME_NO_FUNCTION_RETURNS |
UNDNAME_NO_ALLOCATION_MODEL |
UNDNAME_NO_ALLOCATION_LANGUAGE |
UNDNAME_NO_THISTYPE |
UNDNAME_NO_ACCESS_SPECIFIERS |
UNDNAME_NO_THROW_SIGNATURES |
UNDNAME_NO_MEMBER_TYPE |
UNDNAME_NO_RETURN_UDT_MODEL |
UNDNAME_NO_ECSU;
#define arraysize(f) (sizeof(f) / sizeof(*f))
void StripLlvmSuffixAndUndecorate(BSTR* name) {
// LLVM sometimes puts a suffix on symbols to give them a globally unique
// name. The suffix is either some string preceded by a period (like in the
// Itanium ABI; also on Windows this is safe since periods are otherwise
// never part of mangled names), or a dollar sign followed by a 32-char hex
// string (this should go away in future LLVM versions). Strip such suffixes
// and try demangling again.
//
//
// Example symbol names with such suffixes:
//
// ?foo@@YAXXZ$5520c83448162c04f2b239db4b5a2c61
// ?foo@@YAXXZ.llvm.13040715209719948753
if (**name != L'?')
return; // The name is already demangled.
for (size_t i = 0, len = wcslen(*name); i < len; i++) {
wchar_t c = (*name)[i];
if (c == L'.' || (c == L'$' && len - i == 32 + 1)) {
(*name)[i] = L'\0';
wchar_t undecorated[1024];
DWORD res = UnDecorateSymbolNameW(*name, undecorated,
arraysize(undecorated),
kUndecorateOptions);
if (res == 0 || undecorated[0] == L'?') {
// Demangling failed; restore the symbol name and return.
(*name)[i] = c;
return;
}
SysFreeString(*name);
*name = SysAllocString(undecorated);
return;
}
}
}
// Prints the error message related to the error code as seen in
// Microsoft's MSVS documentation for loadDataFromPdb and loadDataForExe.
void PrintOpenError(HRESULT hr, const char* fn_name, const wchar_t* file) {
switch (hr) {
case E_PDB_NOT_FOUND:
fprintf(stderr, "%s: Failed to open %ws, or the file has an "
"invalid format.\n", fn_name, file);
break;
case E_PDB_FORMAT:
fprintf(stderr, "%s: Attempted to access %ws with an obsolete "
"format.\n", fn_name, file);
break;
case E_PDB_INVALID_SIG:
fprintf(stderr, "%s: Signature does not match for %ws.\n", fn_name,
file);
break;
case E_PDB_INVALID_AGE:
fprintf(stderr, "%s: Age does not match for %ws.\n", fn_name, file);
break;
case E_INVALIDARG:
fprintf(stderr, "%s: Invalid parameter for %ws.\n", fn_name, file);
break;
case E_UNEXPECTED:
fprintf(stderr, "%s: Data source has already been prepared for %ws.\n",
fn_name, file);
break;
default:
fprintf(stderr, "%s: Unexpected error 0x%lx, file: %ws.\n",
fn_name, hr, file);
break;
}
}
} // namespace
PDBSourceLineWriter::Inline::Inline(int inline_nest_level)
: inline_nest_level_(inline_nest_level) {}
void PDBSourceLineWriter::Inline::SetOriginId(int origin_id) {
origin_id_ = origin_id;
}
void PDBSourceLineWriter::Inline::ExtendRanges(const Line& line) {
if (ranges_.empty()) {
ranges_[line.rva] = line.length;
return;
}
auto iter = ranges_.lower_bound(line.rva);
// There is no overlap if this function is called with inlinee lines from
// the same callsite.
if (iter == ranges_.begin()) {
return;
}
if (line.rva + line.length == iter->first) {
// If they are connected, merge their ranges into one.
DWORD length = line.length + iter->second;
ranges_.erase(iter);
ranges_[line.rva] = length;
} else {
--iter;
if (iter->first + iter->second == line.rva) {
ranges_[iter->first] = iter->second + line.length;
} else {
ranges_[line.rva] = line.length;
}
}
}
void PDBSourceLineWriter::Inline::SetCallSiteLine(DWORD call_site_line) {
call_site_line_ = call_site_line;
}
void PDBSourceLineWriter::Inline::SetCallSiteFileId(DWORD call_site_file_id) {
call_site_file_id_ = call_site_file_id;
}
void PDBSourceLineWriter::Inline::SetChildInlines(
vector<unique_ptr<Inline>> child_inlines) {
child_inlines_ = std::move(child_inlines);
}
void PDBSourceLineWriter::Inline::Print(FILE* output) const {
// Ignore INLINE record that doesn't have any range.
if (ranges_.empty())
return;
fprintf(output, "INLINE %d %lu %lu %d", inline_nest_level_, call_site_line_,
call_site_file_id_, origin_id_);
for (const auto& r : ranges_) {
fprintf(output, " %lx %lx", r.first, r.second);
}
fprintf(output, "\n");
for (const unique_ptr<Inline>& in : child_inlines_) {
in->Print(output);
}
}
const PDBSourceLineWriter::Line* PDBSourceLineWriter::Lines::GetLine(
DWORD rva) const {
auto iter = line_map_.find(rva);
if (iter == line_map_.end()) {
// If not found exact rva, check if it's within any range.
iter = line_map_.lower_bound(rva);
if (iter == line_map_.begin())
return nullptr;
--iter;
auto l = iter->second;
// This happens when there is no top level lines cover this rva (e.g. empty
// lines found for the function). Then we don't know the call site line
// number for this inlined function.
if (rva >= l.rva + l.length)
return nullptr;
}
return &iter->second;
}
DWORD PDBSourceLineWriter::Lines::GetLineNum(DWORD rva) const {
const Line* line = GetLine(rva);
return line ? line->line_num : 0;
}
DWORD PDBSourceLineWriter::Lines::GetFileId(DWORD rva) const {
const Line* line = GetLine(rva);
return line ? line->file_id : 0;
}
void PDBSourceLineWriter::Lines::AddLine(const Line& line) {
if (line_map_.empty()) {
line_map_[line.rva] = line;
return;
}
// Given an existing line in line_map_, remove it from line_map_ if it
// overlaps with the line and add a new line for the non-overlap range. Return
// true if there is an overlap.
auto intercept = [&](Line old_line) {
DWORD end = old_line.rva + old_line.length;
// No overlap.
if (old_line.rva >= line.rva + line.length || line.rva >= end)
return false;
// old_line is within the line.
if (old_line.rva >= line.rva && end <= line.rva + line.length) {
line_map_.erase(old_line.rva);
return true;
}
// Then there is a overlap.
if (old_line.rva < line.rva) {
old_line.length -= end - line.rva;
if (end > line.rva + line.length) {
Line new_line = old_line;
new_line.rva = line.rva + line.length;
new_line.length = end - new_line.rva;
line_map_[new_line.rva] = new_line;
}
} else {
line_map_.erase(old_line.rva);
old_line.length -= line.rva + line.length - old_line.rva;
old_line.rva = line.rva + line.length;
}
line_map_[old_line.rva] = old_line;
return true;
};
bool is_intercept;
// Use a loop in cases that there are multiple lines within the given line.
do {
auto iter = line_map_.lower_bound(line.rva);
if (iter == line_map_.end()) {
if (!line_map_.empty()) {
--iter;
intercept(iter->second);
}
break;
}
is_intercept = false;
if (iter != line_map_.begin()) {
// Check if the given line overlaps a line with smaller in the map.
auto prev = line_map_.lower_bound(line.rva);
--prev;
is_intercept = intercept(prev->second);
}
// Check if the given line overlaps a line with greater or equal rva in the
// map. Using operator |= here since it's possible that there are multiple
// lines with greater rva in the map overlap with the given line.
is_intercept |= intercept(iter->second);
} while (is_intercept);
line_map_[line.rva] = line;
}
PDBSourceLineWriter::PDBSourceLineWriter(bool handle_inline)
: output_(NULL), handle_inline_(handle_inline) {}
PDBSourceLineWriter::~PDBSourceLineWriter() {
Close();
}
bool PDBSourceLineWriter::SetCodeFile(const wstring& exe_file) {
if (code_file_.empty()) {
code_file_ = exe_file;
return true;
}
// Setting a different code file path is an error. It is success only if the
// file paths are the same.
return exe_file == code_file_;
}
bool PDBSourceLineWriter::Open(const wstring& file, FileFormat format) {
Close();
code_file_.clear();
if (FAILED(CoInitialize(NULL))) {
fprintf(stderr, "CoInitialize failed\n");
return false;
}
CComPtr<IDiaDataSource> data_source;
if (!CreateDiaDataSourceInstance(data_source)) {
const int kGuidSize = 64;
wchar_t classid[kGuidSize] = {0};
StringFromGUID2(CLSID_DiaSource, classid, kGuidSize);
fprintf(stderr, "CoCreateInstance CLSID_DiaSource %S failed "
"(msdia*.dll unregistered?)\n", classid);
return false;
}
HRESULT from_pdb_result;
HRESULT for_exe_result;
const wchar_t* file_name = file.c_str();
switch (format) {
case PDB_FILE:
from_pdb_result = data_source->loadDataFromPdb(file_name);
if (FAILED(from_pdb_result)) {
PrintOpenError(from_pdb_result, "loadDataFromPdb", file_name);
return false;
}
break;
case EXE_FILE:
for_exe_result = data_source->loadDataForExe(file_name, NULL, NULL);
if (FAILED(for_exe_result)) {
PrintOpenError(for_exe_result, "loadDataForExe", file_name);
return false;
}
code_file_ = file;
break;
case ANY_FILE:
from_pdb_result = data_source->loadDataFromPdb(file_name);
if (FAILED(from_pdb_result)) {
for_exe_result = data_source->loadDataForExe(file_name, NULL, NULL);
if (FAILED(for_exe_result)) {
PrintOpenError(from_pdb_result, "loadDataFromPdb", file_name);
PrintOpenError(for_exe_result, "loadDataForExe", file_name);
return false;
}
code_file_ = file;
}
break;
default:
fprintf(stderr, "Unknown file format\n");
return false;
}
if (FAILED(data_source->openSession(&session_))) {
fprintf(stderr, "openSession failed\n");
}
return true;
}
bool PDBSourceLineWriter::GetLine(IDiaLineNumber* dia_line, Line* line) const {
if (FAILED(dia_line->get_relativeVirtualAddress(&line->rva))) {
fprintf(stderr, "failed to get line rva\n");
return false;
}
if (FAILED(dia_line->get_length(&line->length))) {
fprintf(stderr, "failed to get line code length\n");
return false;
}
DWORD dia_source_id;
if (FAILED(dia_line->get_sourceFileId(&dia_source_id))) {
fprintf(stderr, "failed to get line source file id\n");
return false;
}
// duplicate file names are coalesced to share one ID
line->file_id = GetRealFileID(dia_source_id);
if (FAILED(dia_line->get_lineNumber(&line->line_num))) {
fprintf(stderr, "failed to get line number\n");
return false;
}
return true;
}
bool PDBSourceLineWriter::GetLines(IDiaEnumLineNumbers* lines,
Lines* line_list) const {
CComPtr<IDiaLineNumber> line;
ULONG count;
while (SUCCEEDED(lines->Next(1, &line, &count)) && count == 1) {
Line l;
if (!GetLine(line, &l))
return false;
// Silently ignore zero-length lines.
if (l.length != 0)
line_list->AddLine(l);
line.Release();
}
return true;
}
void PDBSourceLineWriter::PrintLines(const Lines& lines) const {
// The line number format is:
// <rva> <line number> <source file id>
for (const auto& kv : lines.GetLineMap()) {
const Line& l = kv.second;
AddressRangeVector ranges;
MapAddressRange(image_map_, AddressRange(l.rva, l.length), &ranges);
for (auto& range : ranges) {
fprintf(output_, "%lx %lx %lu %lu\n", range.rva, range.length, l.line_num,
l.file_id);
}
}
}
bool PDBSourceLineWriter::PrintFunction(IDiaSymbol* function,
IDiaSymbol* block,
bool has_multiple_symbols) {
// The function format is:
// FUNC <address> <length> <param_stack_size> <function>
DWORD rva;
if (FAILED(block->get_relativeVirtualAddress(&rva))) {
fprintf(stderr, "couldn't get rva\n");
return false;
}
ULONGLONG length;
if (FAILED(block->get_length(&length))) {
fprintf(stderr, "failed to get function length\n");
return false;
}
if (length == 0) {
// Silently ignore zero-length functions, which can infrequently pop up.
return true;
}
CComBSTR name;
int stack_param_size;
if (!GetSymbolFunctionName(function, &name, &stack_param_size)) {
return false;
}
// If the decorated name didn't give the parameter size, try to
// calculate it.
if (stack_param_size < 0) {
stack_param_size = GetFunctionStackParamSize(function);
}
AddressRangeVector ranges;
MapAddressRange(image_map_, AddressRange(rva, static_cast<DWORD>(length)),
&ranges);
for (size_t i = 0; i < ranges.size(); ++i) {
const char* optional_multiple_field = has_multiple_symbols ? "m " : "";
fprintf(output_, "FUNC %s%lx %lx %x %ws\n", optional_multiple_field,
ranges[i].rva, ranges[i].length, stack_param_size, name.m_str);
}
CComPtr<IDiaEnumLineNumbers> lines;
if (FAILED(session_->findLinesByRVA(rva, DWORD(length), &lines))) {
return false;
}
// Get top level lines first, which later may be split into multiple smaller
// lines if any inline exists in their ranges if we want to handle inline.
Lines line_list;
if (!GetLines(lines, &line_list)) {
return false;
}
if (handle_inline_) {
vector<unique_ptr<Inline>> inlines;
if (!GetInlines(block, &line_list, 0, &inlines)) {
return false;
}
PrintInlines(inlines);
}
PrintLines(line_list);
return true;
}
bool PDBSourceLineWriter::PrintSourceFiles() {
CComPtr<IDiaSymbol> global;
if (FAILED(session_->get_globalScope(&global))) {
fprintf(stderr, "get_globalScope failed\n");
return false;
}
CComPtr<IDiaEnumSymbols> compilands;
if (FAILED(global->findChildren(SymTagCompiland, NULL,
nsNone, &compilands))) {
fprintf(stderr, "findChildren failed\n");
return false;
}
// Print a dummy file with id equals 0 to represent unknown file, because
// inline records might have unknown call site.
fwprintf(output_, L"FILE %d unknown file\n", 0);
CComPtr<IDiaSymbol> compiland;
ULONG count;
while (SUCCEEDED(compilands->Next(1, &compiland, &count)) && count == 1) {
CComPtr<IDiaEnumSourceFiles> source_files;
if (FAILED(session_->findFile(compiland, NULL, nsNone, &source_files))) {
return false;
}
CComPtr<IDiaSourceFile> file;
while (SUCCEEDED(source_files->Next(1, &file, &count)) && count == 1) {
DWORD file_id;
if (FAILED(file->get_uniqueId(&file_id))) {
return false;
}
CComBSTR file_name;
if (FAILED(file->get_fileName(&file_name))) {
return false;
}
wstring file_name_string(file_name);
if (!FileIDIsCached(file_name_string)) {
// this is a new file name, cache it and output a FILE line.
CacheFileID(file_name_string, file_id);
fwprintf(output_, L"FILE %d %ws\n", file_id, file_name_string.c_str());
} else {
// this file name has already been seen, just save this
// ID for later lookup.
StoreDuplicateFileID(file_name_string, file_id);
}
file.Release();
}
compiland.Release();
}
return true;
}
bool PDBSourceLineWriter::PrintFunctions() {
ULONG count = 0;
DWORD rva = 0;
CComPtr<IDiaSymbol> global;
HRESULT hr;
if (FAILED(session_->get_globalScope(&global))) {
fprintf(stderr, "get_globalScope failed\n");
return false;
}
CComPtr<IDiaEnumSymbols> symbols = NULL;
// Find all function symbols first.
SymbolMap rva_symbol;
hr = global->findChildren(SymTagFunction, NULL, nsNone, &symbols);
if (SUCCEEDED(hr)) {
CComPtr<IDiaSymbol> symbol = NULL;
while (SUCCEEDED(symbols->Next(1, &symbol, &count)) && count == 1) {
if (SUCCEEDED(symbol->get_relativeVirtualAddress(&rva))) {
// Potentially record this as the canonical symbol for this rva.
MaybeRecordSymbol(rva, symbol, false, &rva_symbol);
} else {
fprintf(stderr, "get_relativeVirtualAddress failed on the symbol\n");
return false;
}
symbol.Release();
}
symbols.Release();
}
// Find all public symbols and record public symbols that are not also private
// symbols.
hr = global->findChildren(SymTagPublicSymbol, NULL, nsNone, &symbols);
if (SUCCEEDED(hr)) {
CComPtr<IDiaSymbol> symbol = NULL;
while (SUCCEEDED(symbols->Next(1, &symbol, &count)) && count == 1) {
if (SUCCEEDED(symbol->get_relativeVirtualAddress(&rva))) {
// Potentially record this as the canonical symbol for this rva.
MaybeRecordSymbol(rva, symbol, true, &rva_symbol);
} else {
fprintf(stderr, "get_relativeVirtualAddress failed on the symbol\n");
return false;
}
symbol.Release();
}
symbols.Release();
}
// For each rva, dump the selected symbol at the address.
SymbolMap::iterator it;
for (it = rva_symbol.begin(); it != rva_symbol.end(); ++it) {
CComPtr<IDiaSymbol> symbol = it->second.symbol;
// Only print public symbols if there is no function symbol for the address.
if (!it->second.is_public) {
if (!PrintFunction(symbol, symbol, it->second.is_multiple))
return false;
} else {
if (!PrintCodePublicSymbol(symbol, it->second.is_multiple))
return false;
}
}
// When building with PGO, the compiler can split functions into
// "hot" and "cold" blocks, and move the "cold" blocks out to separate
// pages, so the function can be noncontiguous. To find these blocks,
// we have to iterate over all the compilands, and then find blocks
// that are children of them. We can then find the lexical parents
// of those blocks and print out an extra FUNC line for blocks
// that are not contained in their parent functions.
CComPtr<IDiaEnumSymbols> compilands;
if (FAILED(global->findChildren(SymTagCompiland, NULL,
nsNone, &compilands))) {
fprintf(stderr, "findChildren failed on the global\n");
return false;
}
CComPtr<IDiaSymbol> compiland;
while (SUCCEEDED(compilands->Next(1, &compiland, &count)) && count == 1) {
CComPtr<IDiaEnumSymbols> blocks;
if (FAILED(compiland->findChildren(SymTagBlock, NULL,
nsNone, &blocks))) {
fprintf(stderr, "findChildren failed on a compiland\n");
return false;
}
CComPtr<IDiaSymbol> block;
while (SUCCEEDED(blocks->Next(1, &block, &count)) && count == 1) {
// find this block's lexical parent function
CComPtr<IDiaSymbol> parent;
DWORD tag;
if (SUCCEEDED(block->get_lexicalParent(&parent)) &&
SUCCEEDED(parent->get_symTag(&tag)) &&
tag == SymTagFunction) {
// now get the block's offset and the function's offset and size,
// and determine if the block is outside of the function
DWORD func_rva, block_rva;
ULONGLONG func_length;
if (SUCCEEDED(block->get_relativeVirtualAddress(&block_rva)) &&
SUCCEEDED(parent->get_relativeVirtualAddress(&func_rva)) &&
SUCCEEDED(parent->get_length(&func_length))) {
if (block_rva < func_rva || block_rva > (func_rva + func_length)) {
if (!PrintFunction(parent, block, false)) {
return false;
}
}
}
}
parent.Release();
block.Release();
}
blocks.Release();
compiland.Release();
}
global.Release();
return true;
}
void PDBSourceLineWriter::PrintInlineOrigins() const {
struct OriginCompare {
bool operator()(const InlineOrigin lhs, const InlineOrigin rhs) const {
return lhs.id < rhs.id;
}
};
set<InlineOrigin, OriginCompare> origins;
// Sort by origin id.
for (auto const& origin : inline_origins_)
origins.insert(origin.second);
for (auto o : origins) {
fprintf(output_, "INLINE_ORIGIN %d %ls\n", o.id, o.name.c_str());
}
}
bool PDBSourceLineWriter::GetInlines(IDiaSymbol* block,
Lines* line_list,
int inline_nest_level,
vector<unique_ptr<Inline>>* inlines) {
CComPtr<IDiaEnumSymbols> inline_callsites;
if (FAILED(block->findChildrenEx(SymTagInlineSite, nullptr, nsNone,
&inline_callsites))) {
return false;
}
ULONG count;
CComPtr<IDiaSymbol> callsite;
while (SUCCEEDED(inline_callsites->Next(1, &callsite, &count)) &&
count == 1) {
unique_ptr<Inline> new_inline(new Inline(inline_nest_level));
CComPtr<IDiaEnumLineNumbers> lines;
// All inlinee lines have the same file id.
DWORD file_id = 0;
DWORD call_site_line = 0;
if (FAILED(session_->findInlineeLines(callsite, &lines))) {
return false;
}
CComPtr<IDiaLineNumber> dia_line;
while (SUCCEEDED(lines->Next(1, &dia_line, &count)) && count == 1) {
Line line;
if (!GetLine(dia_line, &line)) {
return false;
}
// Silently ignore zero-length lines.
if (line.length != 0) {
// Use the first line num and file id at rva as this inline's call site
// line number, because after adding lines it may be changed to inner
// line number and inner file id.
if (call_site_line == 0)
call_site_line = line_list->GetLineNum(line.rva);
if (file_id == 0)
file_id = line_list->GetFileId(line.rva);
line_list->AddLine(line);
new_inline->ExtendRanges(line);
}
dia_line.Release();
}
BSTR name;
callsite->get_name(&name);
if (SysStringLen(name) == 0) {
name = SysAllocString(L"<name omitted>");
}
auto iter = inline_origins_.find(name);
if (iter == inline_origins_.end()) {
InlineOrigin origin;
origin.id = inline_origins_.size();
origin.name = name;
inline_origins_[name] = origin;
}
new_inline->SetOriginId(inline_origins_[name].id);
new_inline->SetCallSiteLine(call_site_line);
new_inline->SetCallSiteFileId(file_id);
// Go to next level.
vector<unique_ptr<Inline>> child_inlines;
if (!GetInlines(callsite, line_list, inline_nest_level + 1,
&child_inlines)) {
return false;
}
new_inline->SetChildInlines(std::move(child_inlines));
inlines->push_back(std::move(new_inline));
callsite.Release();
}
return true;
}
void PDBSourceLineWriter::PrintInlines(
const vector<unique_ptr<Inline>>& inlines) const {
for (const unique_ptr<Inline>& in : inlines) {
in->Print(output_);
}
}
#undef max
bool PDBSourceLineWriter::PrintFrameDataUsingPDB() {
// It would be nice if it were possible to output frame data alongside the
// associated function, as is done with line numbers, but the DIA API
// doesn't make it possible to get the frame data in that way.
CComPtr<IDiaEnumFrameData> frame_data_enum;
if (!FindTable(session_, &frame_data_enum))
return false;
DWORD last_type = std::numeric_limits<DWORD>::max();
DWORD last_rva = std::numeric_limits<DWORD>::max();
DWORD last_code_size = 0;
DWORD last_prolog_size = std::numeric_limits<DWORD>::max();
CComPtr<IDiaFrameData> frame_data;
ULONG count = 0;
while (SUCCEEDED(frame_data_enum->Next(1, &frame_data, &count)) &&
count == 1) {
DWORD type;
if (FAILED(frame_data->get_type(&type)))
return false;
DWORD rva;
if (FAILED(frame_data->get_relativeVirtualAddress(&rva)))
return false;
DWORD code_size;
if (FAILED(frame_data->get_lengthBlock(&code_size)))
return false;
DWORD prolog_size;
if (FAILED(frame_data->get_lengthProlog(&prolog_size)))
return false;
// parameter_size is the size of parameters passed on the stack. If any
// parameters are not passed on the stack (such as in registers), their
// sizes will not be included in parameter_size.
DWORD parameter_size;
if (FAILED(frame_data->get_lengthParams(¶meter_size)))
return false;
DWORD saved_register_size;
if (FAILED(frame_data->get_lengthSavedRegisters(&saved_register_size)))
return false;
DWORD local_size;
if (FAILED(frame_data->get_lengthLocals(&local_size)))
return false;
// get_maxStack can return S_FALSE, just use 0 in that case.
DWORD max_stack_size = 0;
if (FAILED(frame_data->get_maxStack(&max_stack_size)))
return false;
// get_programString can return S_FALSE, indicating that there is no
// program string. In that case, check whether %ebp is used.
HRESULT program_string_result;
CComBSTR program_string;
if (FAILED(program_string_result = frame_data->get_program(
&program_string))) {
return false;
}
// get_allocatesBasePointer can return S_FALSE, treat that as though
// %ebp is not used.
BOOL allocates_base_pointer = FALSE;
if (program_string_result != S_OK) {
if (FAILED(frame_data->get_allocatesBasePointer(
&allocates_base_pointer))) {
return false;
}
}
// Only print out a line if type, rva, code_size, or prolog_size have
// changed from the last line. It is surprisingly common (especially in
// system library PDBs) for DIA to return a series of identical
// IDiaFrameData objects. For kernel32.pdb from Windows XP SP2 on x86,
// this check reduces the size of the dumped symbol file by a third.
if (type != last_type || rva != last_rva || code_size != last_code_size ||
prolog_size != last_prolog_size) {
// The prolog and the code portions of the frame have to be treated
// independently as they may have independently changed in size, or may
// even have been split.
// NOTE: If epilog size is ever non-zero, we have to do something
// similar with it.
// Figure out where the prolog bytes have landed.
AddressRangeVector prolog_ranges;
if (prolog_size > 0) {
MapAddressRange(image_map_, AddressRange(rva, prolog_size),
&prolog_ranges);
}
// And figure out where the code bytes have landed.
AddressRangeVector code_ranges;
MapAddressRange(image_map_,
AddressRange(rva + prolog_size,
code_size - prolog_size),
&code_ranges);
struct FrameInfo {
DWORD rva;
DWORD code_size;
DWORD prolog_size;
};
std::vector<FrameInfo> frame_infos;
// Special case: The prolog and the code bytes remain contiguous. This is
// only done for compactness of the symbol file, and we could actually
// be outputting independent frame info for the prolog and code portions.
if (prolog_ranges.size() == 1 && code_ranges.size() == 1 &&
prolog_ranges[0].end() == code_ranges[0].rva) {
FrameInfo fi = { prolog_ranges[0].rva,
prolog_ranges[0].length + code_ranges[0].length,
prolog_ranges[0].length };
frame_infos.push_back(fi);
} else {
// Otherwise we output the prolog and code frame info independently.
for (size_t i = 0; i < prolog_ranges.size(); ++i) {
FrameInfo fi = { prolog_ranges[i].rva,
prolog_ranges[i].length,
prolog_ranges[i].length };
frame_infos.push_back(fi);
}
for (size_t i = 0; i < code_ranges.size(); ++i) {
FrameInfo fi = { code_ranges[i].rva, code_ranges[i].length, 0 };
frame_infos.push_back(fi);
}
}
for (size_t i = 0; i < frame_infos.size(); ++i) {
const FrameInfo& fi(frame_infos[i]);
fprintf(output_, "STACK WIN %lx %lx %lx %lx %x %lx %lx %lx %lx %d ",
type, fi.rva, fi.code_size, fi.prolog_size,
0 /* epilog_size */, parameter_size, saved_register_size,
local_size, max_stack_size, program_string_result == S_OK);
if (program_string_result == S_OK) {
fprintf(output_, "%ws\n", program_string.m_str);
} else {
fprintf(output_, "%d\n", allocates_base_pointer);
}
}
last_type = type;
last_rva = rva;
last_code_size = code_size;
last_prolog_size = prolog_size;
}
frame_data.Release();
}
return true;
}
bool PDBSourceLineWriter::PrintFrameDataUsingEXE() {
if (code_file_.empty() && !FindPEFile()) {
fprintf(stderr, "Couldn't locate EXE or DLL file.\n");
return false;
}
return PrintPEFrameData(code_file_, output_);
}
bool PDBSourceLineWriter::PrintFrameData() {
PDBModuleInfo info;
if (GetModuleInfo(&info) && info.cpu == L"x86_64") {
return PrintFrameDataUsingEXE();
}
return PrintFrameDataUsingPDB();
}
bool PDBSourceLineWriter::PrintCodePublicSymbol(IDiaSymbol* symbol,
bool has_multiple_symbols) {
BOOL is_code;
if (FAILED(symbol->get_code(&is_code))) {
return false;
}
if (!is_code) {
return true;
}
DWORD rva;
if (FAILED(symbol->get_relativeVirtualAddress(&rva))) {
return false;
}
CComBSTR name;
int stack_param_size;
if (!GetSymbolFunctionName(symbol, &name, &stack_param_size)) {
return false;
}
AddressRangeVector ranges;
MapAddressRange(image_map_, AddressRange(rva, 1), &ranges);
for (size_t i = 0; i < ranges.size(); ++i) {
const char* optional_multiple_field = has_multiple_symbols ? "m " : "";
fprintf(output_, "PUBLIC %s%lx %x %ws\n", optional_multiple_field,
ranges[i].rva, stack_param_size > 0 ? stack_param_size : 0,
name.m_str);
}
// Now walk the function in the original untranslated space, asking DIA
// what function is at that location, stepping through OMAP blocks. If
// we're still in the same function, emit another entry, because the
// symbol could have been split into multiple pieces. If we've gotten to
// another symbol in the original address space, then we're done for
// this symbol. See https://crbug.com/678874.
for (;;) {
// This steps to the next block in the original image. Simply doing
// rva++ would also be correct, but would emit tons of unnecessary
// entries.
rva = image_map_.subsequent_rva_block[rva];
if (rva == 0)
break;
CComPtr<IDiaSymbol> next_sym = NULL;
LONG displacement;
if (FAILED(session_->findSymbolByRVAEx(rva, SymTagPublicSymbol, &next_sym,
&displacement))) {
break;
}
if (!SymbolsMatch(symbol, next_sym))
break;
AddressRangeVector next_ranges;
MapAddressRange(image_map_, AddressRange(rva, 1), &next_ranges);
for (size_t i = 0; i < next_ranges.size(); ++i) {
fprintf(output_, "PUBLIC %lx %x %ws\n", next_ranges[i].rva,
stack_param_size > 0 ? stack_param_size : 0, name.m_str);
}
}
return true;
}
bool PDBSourceLineWriter::PrintPDBInfo() {
PDBModuleInfo info;
if (!GetModuleInfo(&info)) {
return false;
}
// Hard-code "windows" for the OS because that's the only thing that makes
// sense for PDB files. (This might not be strictly correct for Windows CE
// support, but we don't care about that at the moment.)
fprintf(output_, "MODULE windows %ws %ws %ws\n",
info.cpu.c_str(), info.debug_identifier.c_str(),
info.debug_file.c_str());
return true;
}
bool PDBSourceLineWriter::PrintPEInfo() {
PEModuleInfo info;
if (!GetPEInfo(&info)) {
return false;
}
fprintf(output_, "INFO CODE_ID %ws %ws\n",
info.code_identifier.c_str(),
info.code_file.c_str());
return true;
}
// wcstol_positive_strict is sort of like wcstol, but much stricter. string
// should be a buffer pointing to a null-terminated string containing only
// decimal digits. If the entire string can be converted to an integer
// without overflowing, and there are no non-digit characters before the
// result is set to the value and this function returns true. Otherwise,
// this function returns false. This is an alternative to the strtol, atoi,
// and scanf families, which are not as strict about input and in some cases
// don't provide a good way for the caller to determine if a conversion was
// successful.
static bool wcstol_positive_strict(wchar_t* string, int* result) {
int value = 0;
for (wchar_t* c = string; *c != '\0'; ++c) {
int last_value = value;
value *= 10;
// Detect overflow.
if (value / 10 != last_value || value < 0) {
return false;
}
if (*c < '0' || *c > '9') {
return false;
}
unsigned int c_value = *c - '0';
last_value = value;
value += c_value;
// Detect overflow.
if (value < last_value) {
return false;
}
// Forbid leading zeroes unless the string is just "0".
if (value == 0 && *(c+1) != '\0') {
return false;
}
}
*result = value;
return true;
}
bool PDBSourceLineWriter::FindPEFile() {
CComPtr<IDiaSymbol> global;
if (FAILED(session_->get_globalScope(&global))) {
fprintf(stderr, "get_globalScope failed\n");
return false;
}
CComBSTR symbols_file;
if (SUCCEEDED(global->get_symbolsFileName(&symbols_file))) {
wstring file(symbols_file);
// Look for an EXE or DLL file.
const wchar_t* extensions[] = { L"exe", L"dll" };
for (size_t i = 0; i < sizeof(extensions) / sizeof(extensions[0]); i++) {
size_t dot_pos = file.find_last_of(L".");
if (dot_pos != wstring::npos) {
file.replace(dot_pos + 1, wstring::npos, extensions[i]);
// Check if this file exists.
if (GetFileAttributesW(file.c_str()) != INVALID_FILE_ATTRIBUTES) {
code_file_ = file;
return true;
}
}
}
}
return false;
}
// static
bool PDBSourceLineWriter::GetSymbolFunctionName(IDiaSymbol* function,
BSTR* name,
int* stack_param_size) {
*stack_param_size = -1;
// Use get_undecoratedNameEx to get readable C++ names with arguments.
if (function->get_undecoratedNameEx(kUndecorateOptions, name) != S_OK) {
if (function->get_name(name) != S_OK) {
fprintf(stderr, "failed to get function name\n");
return false;
}
// It's possible for get_name to return an empty string, so
// special-case that.
if (wcscmp(*name, L"") == 0) {
SysFreeString(*name);
// dwarf_cu_to_module.cc uses "<name omitted>", so match that.
*name = SysAllocString(L"<name omitted>");
return true;
}
// If a name comes from get_name because no undecorated form existed,
// it's already formatted properly to be used as output. Don't do any
// additional processing.
//
// MSVC7's DIA seems to not undecorate names in as many cases as MSVC8's.
// This will result in calling get_name for some C++ symbols, so
// all of the parameter and return type information may not be included in
// the name string.
} else {
StripLlvmSuffixAndUndecorate(name);
// C++ uses a bogus "void" argument for functions and methods that don't
// take any parameters. Take it out of the undecorated name because it's
// ugly and unnecessary.
const wchar_t* replace_string = L"(void)";
const size_t replace_length = wcslen(replace_string);
const wchar_t* replacement_string = L"()";
size_t length = wcslen(*name);
if (length >= replace_length) {
wchar_t* name_end = *name + length - replace_length;
if (wcscmp(name_end, replace_string) == 0) {
WindowsStringUtils::safe_wcscpy(name_end, replace_length,
replacement_string);
length = wcslen(*name);
}
}
// Undecorate names used for stdcall and fastcall. These names prefix
// the identifier with '_' (stdcall) or '@' (fastcall) and suffix it
// with '@' followed by the number of bytes of parameters, in decimal.
// If such a name is found, take note of the size and undecorate it.
// Only do this for names that aren't C++, which is determined based on
// whether the undecorated name contains any ':' or '(' characters.
if (!wcschr(*name, ':') && !wcschr(*name, '(') &&
(*name[0] == '_' || *name[0] == '@')) {
wchar_t* last_at = wcsrchr(*name + 1, '@');
if (last_at && wcstol_positive_strict(last_at + 1, stack_param_size)) {
// If this function adheres to the fastcall convention, it accepts up
// to the first 8 bytes of parameters in registers (%ecx and %edx).
// We're only interested in the stack space used for parameters, so
// so subtract 8 and don't let the size go below 0.
if (*name[0] == '@') {
if (*stack_param_size > 8) {
*stack_param_size -= 8;
} else {
*stack_param_size = 0;
}
}
// Undecorate the name by moving it one character to the left in its
// buffer, and terminating it where the last '@' had been.
WindowsStringUtils::safe_wcsncpy(*name, length,
*name + 1, last_at - *name - 1);
} else if (*name[0] == '_') {
// This symbol's name is encoded according to the cdecl rules. The
// name doesn't end in a '@' character followed by a decimal positive
// integer, so it's not a stdcall name. Strip off the leading
// underscore.
WindowsStringUtils::safe_wcsncpy(*name, length, *name + 1, length);
}
}
}
return true;
}
// static
int PDBSourceLineWriter::GetFunctionStackParamSize(IDiaSymbol* function) {
// This implementation is highly x86-specific.
// Gather the symbols corresponding to data.
CComPtr<IDiaEnumSymbols> data_children;
if (FAILED(function->findChildren(SymTagData, NULL, nsNone,
&data_children))) {
return 0;
}
// lowest_base is the lowest %ebp-relative byte offset used for a parameter.
// highest_end is one greater than the highest offset (i.e. base + length).
// Stack parameters are assumed to be contiguous, because in reality, they
// are.
int lowest_base = INT_MAX;
int highest_end = INT_MIN;
CComPtr<IDiaSymbol> child;
DWORD count;
while (SUCCEEDED(data_children->Next(1, &child, &count)) && count == 1) {
// If any operation fails at this point, just proceed to the next child.
// Use the next_child label instead of continue because child needs to
// be released before it's reused. Declare constructable/destructable
// types early to avoid gotos that cross initializations.
CComPtr<IDiaSymbol> child_type;
// DataIsObjectPtr is only used for |this|. Because |this| can be passed
// as a stack parameter, look for it in addition to traditional
// parameters.
DWORD child_kind;
if (FAILED(child->get_dataKind(&child_kind)) ||
(child_kind != DataIsParam && child_kind != DataIsObjectPtr)) {
goto next_child;
}
// Only concentrate on register-relative parameters. Parameters may also
// be enregistered (passed directly in a register), but those don't
// consume any stack space, so they're not of interest.
DWORD child_location_type;
if (FAILED(child->get_locationType(&child_location_type)) ||
child_location_type != LocIsRegRel) {
goto next_child;
}
// Of register-relative parameters, the only ones that make any sense are
// %ebp- or %esp-relative. Note that MSVC's debugging information always
// gives parameters as %ebp-relative even when a function doesn't use a
// traditional frame pointer and stack parameters are accessed relative to
// %esp, so just look for %ebp-relative parameters. If you wanted to
// access parameters, you'd probably want to treat these %ebp-relative
// offsets as if they were relative to %esp before a function's prolog
// executed.
DWORD child_register;
if (FAILED(child->get_registerId(&child_register)) ||
child_register != CV_REG_EBP) {
goto next_child;
}
LONG child_register_offset;
if (FAILED(child->get_offset(&child_register_offset))) {
goto next_child;
}
// IDiaSymbol::get_type can succeed but still pass back a NULL value.
if (FAILED(child->get_type(&child_type)) || !child_type) {
goto next_child;
}
ULONGLONG child_length;
if (FAILED(child_type->get_length(&child_length))) {
goto next_child;
}
// Extra scope to avoid goto jumping over variable initialization
{
int child_end = child_register_offset + static_cast<ULONG>(child_length);
if (child_register_offset < lowest_base) {
lowest_base = child_register_offset;
}
if (child_end > highest_end) {
highest_end = child_end;
}
}
next_child:
child.Release();
}
int param_size = 0;
// Make sure lowest_base isn't less than 4, because [%esp+4] is the lowest
// possible address to find a stack parameter before executing a function's
// prolog (see above). Some optimizations cause parameter offsets to be
// lower than 4, but we're not concerned with those because we're only
// looking for parameters contained in addresses higher than where the
// return address is stored.
if (lowest_base < 4) {
lowest_base = 4;
}
if (highest_end > lowest_base) {
// All stack parameters are pushed as at least 4-byte quantities. If the
// last type was narrower than 4 bytes, promote it. This assumes that all
// parameters' offsets are 4-byte-aligned, which is always the case. Only
// worry about the last type, because we're not summing the type sizes,
// just looking at the lowest and highest offsets.
int remainder = highest_end % 4;
if (remainder) {
highest_end += 4 - remainder;
}
param_size = highest_end - lowest_base;
}
return param_size;
}
bool PDBSourceLineWriter::WriteSymbols(FILE* symbol_file) {
output_ = symbol_file;
// Load the OMAP information, and disable auto-translation of addresses in
// preference of doing it ourselves.
OmapData omap_data;
if (!GetOmapDataAndDisableTranslation(session_, &omap_data))
return false;
BuildImageMap(omap_data, &image_map_);
bool ret = PrintPDBInfo();
// This is not a critical piece of the symbol file.
PrintPEInfo();
ret = ret && PrintSourceFiles() && PrintFunctions() && PrintFrameData();
PrintInlineOrigins();
output_ = NULL;
return ret;
}
void PDBSourceLineWriter::Close() {
if (session_ != nullptr) {
session_.Release();
}
}
bool PDBSourceLineWriter::GetModuleInfo(PDBModuleInfo* info) {
if (!info) {
return false;
}
info->debug_file.clear();
info->debug_identifier.clear();
info->cpu.clear();
CComPtr<IDiaSymbol> global;
if (FAILED(session_->get_globalScope(&global))) {
return false;
}
DWORD machine_type;
// get_machineType can return S_FALSE.
if (global->get_machineType(&machine_type) == S_OK) {
// The documentation claims that get_machineType returns a value from
// the CV_CPU_TYPE_e enumeration, but that's not the case.
// Instead, it returns one of the IMAGE_FILE_MACHINE values as
// defined here:
// http://msdn.microsoft.com/en-us/library/ms680313%28VS.85%29.aspx
info->cpu = FileHeaderMachineToCpuString(static_cast<WORD>(machine_type));
} else {
// Unexpected, but handle gracefully.
info->cpu = L"unknown";
}
// DWORD* and int* are not compatible. This is clean and avoids a cast.
DWORD age;
if (FAILED(global->get_age(&age))) {
return false;
}
bool uses_guid;
if (!UsesGUID(&uses_guid)) {
return false;
}
if (uses_guid) {
GUID guid;
if (FAILED(global->get_guid(&guid))) {
return false;
}
info->debug_identifier = GenerateDebugIdentifier(age, guid);
} else {
DWORD signature;
if (FAILED(global->get_signature(&signature))) {
return false;
}
info->debug_identifier = GenerateDebugIdentifier(age, signature);
}
CComBSTR debug_file_string;
if (FAILED(global->get_symbolsFileName(&debug_file_string))) {
return false;
}
info->debug_file =
WindowsStringUtils::GetBaseName(wstring(debug_file_string));
return true;
}
bool PDBSourceLineWriter::GetPEInfo(PEModuleInfo* info) {
if (!info) {
return false;
}
if (code_file_.empty() && !FindPEFile()) {
fprintf(stderr, "Couldn't locate EXE or DLL file.\n");
return false;
}
return ReadPEInfo(code_file_, info);
}
bool PDBSourceLineWriter::UsesGUID(bool* uses_guid) {
if (!uses_guid)
return false;
CComPtr<IDiaSymbol> global;
if (FAILED(session_->get_globalScope(&global)))
return false;
GUID guid;
if (FAILED(global->get_guid(&guid)))
return false;
DWORD signature;
if (FAILED(global->get_signature(&signature)))
return false;
// There are two possibilities for guid: either it's a real 128-bit GUID
// as identified in a code module by a new-style CodeView record, or it's
// a 32-bit signature (timestamp) as identified by an old-style record.
// See MDCVInfoPDB70 and MDCVInfoPDB20 in minidump_format.h.
//
// Because DIA doesn't provide a way to directly determine whether a module
// uses a GUID or a 32-bit signature, this code checks whether the first 32
// bits of guid are the same as the signature, and if the rest of guid is
// zero. If so, then with a pretty high degree of certainty, there's an
// old-style CodeView record in use. This method will only falsely find an
// an old-style CodeView record if a real 128-bit GUID has its first 32
// bits set the same as the module's signature (timestamp) and the rest of
// the GUID is set to 0. This is highly unlikely.
GUID signature_guid = {signature}; // 0-initializes other members
*uses_guid = !IsEqualGUID(guid, signature_guid);
return true;
}
} // namespace google_breakpad