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[libc++abi] Remove unnecessary dependency on std::unique_ptr #73277

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Merged
merged 1 commit into from
Aug 19, 2024
Merged

[libc++abi] Remove unnecessary dependency on std::unique_ptr #73277

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30 changes: 14 additions & 16 deletions libcxxabi/src/cxa_default_handlers.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -10,8 +10,6 @@
//===----------------------------------------------------------------------===//

#include <exception>
#include <memory>
#include <stdlib.h>
#include "abort_message.h"
#include "cxxabi.h"
#include "cxa_handlers.h"
Expand All @@ -23,17 +21,7 @@

static constinit const char* cause = "uncaught";

#ifndef _LIBCXXABI_NO_EXCEPTIONS
// Demangle the given string, or return the string as-is in case of an error.
static std::unique_ptr<char const, void (*)(char const*)> demangle(char const* str)
{
#if !defined(LIBCXXABI_NON_DEMANGLING_TERMINATE)
if (const char* result = __cxxabiv1::__cxa_demangle(str, nullptr, nullptr, nullptr))
return {result, [](char const* p) { std::free(const_cast<char*>(p)); }};
#endif
return {str, [](char const*) { /* nothing to free */ }};
}

# ifndef _LIBCXXABI_NO_EXCEPTIONS
__attribute__((noreturn))
static void demangling_terminate_handler()
{
Expand Down Expand Up @@ -61,20 +49,30 @@ static void demangling_terminate_handler()
exception_header + 1;
const __shim_type_info* thrown_type =
static_cast<const __shim_type_info*>(exception_header->exceptionType);
auto name = demangle(thrown_type->name());

auto name = [str = thrown_type->name()] {
# ifndef LIBCXXABI_NON_DEMANGLING_TERMINATE
if (const char* result = __cxxabiv1::__cxa_demangle(str, nullptr, nullptr, nullptr))
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https://reviews.llvm.org/D125268 is relevant for a discussion about whether it's OK to leak here given that we're terminating. I think the answer was "yes, it's fine". Tagging @urnathan for awareness.

I wonder if this could cause problems with sanitizers, though.

// We're about to abort(), this memory can never be freed; so it's fine
// to just return a raw pointer
return result;
# endif
return str;
}();

// If the uncaught exception can be caught with std::exception&
const __shim_type_info* catch_type =
static_cast<const __shim_type_info*>(&typeid(std::exception));
if (catch_type->can_catch(thrown_type, thrown_object))
{
// Include the what() message from the exception
const std::exception* e = static_cast<const std::exception*>(thrown_object);
abort_message("terminating due to %s exception of type %s: %s", cause, name.get(), e->what());
abort_message("terminating due to %s exception of type %s: %s", cause, name, e->what());
}
else
{
// Else just note that we're terminating due to an exception
abort_message("terminating due to %s exception of type %s", cause, name.get());
abort_message("terminating due to %s exception of type %s", cause, name);
}
}
#else // !_LIBCXXABI_NO_EXCEPTIONS
Expand Down
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