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Strip LLVM-generated symbol suffixes when demangling Windows symbols

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LLVM, especially in ThinLTO builds, sometimes puts a suffix on symbols
to give them a unique name. For example:

   ?foo@@YAXXZ$5520c83448162c04f2b239db4b5a2c61
   ?foo@@YAXXZ.llvm.1304071520971994875

Strip such suffixes in order to demangle the names.

Bug: chromium:1179132
Change-Id: Ibc8da0c605b95c6b9fc51802a56b89f6e7cfb7e1
Reviewed-on: https://chromium-review.googlesource.com/c/breakpad/breakpad/+/2739612
Reviewed-by: Mark Mentovai <mark@chromium.org>
Reviewed-by: Ivan Penkov <ivanpe@chromium.org>
This commit is contained in:
Hans Wennborg 2021-03-08 19:25:30 +01:00 committed by Mark Mentovai
parent 7279404aea
commit d6a6f52606
1 changed files with 55 additions and 11 deletions
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66
src/common/windows/pdb_source_line_writer.cc
View file

@ -154,6 +154,58 @@ bool CreateDiaDataSourceInstance(CComPtr<IDiaDataSource>& data_source) {
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;
}
}
}
} // namespace
PDBSourceLineWriter::PDBSourceLineWriter() : output_(NULL) {
@ -843,19 +895,9 @@ bool PDBSourceLineWriter::GetSymbolFunctionName(IDiaSymbol* function,
BSTR* name,
int* stack_param_size) {
*stack_param_size = -1;
const DWORD undecorate_options = 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;
// Use get_undecoratedNameEx to get readable C++ names with arguments.
if (function->get_undecoratedNameEx(undecorate_options, name) != S_OK) {
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;
@ -879,6 +921,8 @@ bool PDBSourceLineWriter::GetSymbolFunctionName(IDiaSymbol* function,
// 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.