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edolstracole-h
edolstra
authored and
cole-h
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Abort when throwing std::logic_error
There are many places where a thrown `std::logic_error` is handled like a normal error, making it very difficult to get a good stack trace so we can fix that logic error. So, we wrap the __cxa_throw function such that we can check if the thrown exception was a `std::logic_error`, and if so, abort the process so we can figure out exactly where it happened. Co-authored-by: Eelco Dolstra <edolstra@gmail.com>
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8 files changed

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‎nix-meson-build-support/common/cxa-throw/interpose-cxa-throw.cc‎

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#include <cstdlib>
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#include <dlfcn.h>
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#include <typeinfo>
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#include "is-logic-error.hh"
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#ifndef CXA_THROW_ON_LOGIC_ERROR
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# define CXA_THROW_ON_LOGIC_ERROR() abort()
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#endif
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typedef void (*cxa_throw_type)(void *, std::type_info *, void (*)(void *));
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extern "C" void __cxa_throw(void * exc, std::type_info * tinfo, void (*dest)(void *))
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{
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if (is_logic_error(tinfo))
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CXA_THROW_ON_LOGIC_ERROR();
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static auto * orig = (cxa_throw_type) dlsym(RTLD_NEXT, "__cxa_throw");
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if (!orig)
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abort();
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orig(exc, tinfo, dest);
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__builtin_unreachable();
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}

‎nix-meson-build-support/common/cxa-throw/is-logic-error.hh‎

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#pragma once
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#include <cxxabi.h>
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#include <stdexcept>
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#include <typeinfo>
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static bool is_logic_error(const std::type_info * tinfo)
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{
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if (*tinfo == typeid(std::logic_error))
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return true;
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auto * si = dynamic_cast<const __cxxabiv1::__si_class_type_info *>(tinfo);
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if (si)
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return is_logic_error(si->__base_type);
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return false;
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}

‎nix-meson-build-support/common/cxa-throw/meson.build‎

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have_cxa_throw = false
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can_interpose_cxa_throw_test_code = '''
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#include <string>
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#include <unistd.h>
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#define CXA_THROW_ON_LOGIC_ERROR() _exit(0)
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#include "interpose-cxa-throw.cc"
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int main()
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{
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const char * volatile p = nullptr;
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std::string s(p);
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return 1;
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}
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'''
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can_interpose_cxa_throw_result = cxx.run(
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can_interpose_cxa_throw_test_code,
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args : [ '-ldl' ],
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include_directories : include_directories('.'),
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name : 'can interpose __cxa_throw (catches libstdc++ throws)',
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)
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can_interpose_cxa_throw = can_interpose_cxa_throw_result.compiled() and can_interpose_cxa_throw_result.returncode() == 0
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if can_interpose_cxa_throw
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interpose_cxa_throw_lib = static_library(
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'interpose-cxa-throw',
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'interpose-cxa-throw.cc',
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dependencies : cxx.find_library('dl', required : false),
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)
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cxa_throw_dep = declare_dependency(
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link_whole : interpose_cxa_throw_lib,
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)
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have_cxa_throw = true
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else
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can_wrap_cxa_throw_test_code = '''
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#include <string>
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#include <unistd.h>
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#define CXA_THROW_ON_LOGIC_ERROR() _exit(0)
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#include "wrap-cxa-throw.cc"
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int main()
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{
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const char * volatile p = nullptr;
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std::string s(p);
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return 1;
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}
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'''
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wrap_cxa_throw_args = [ '-Wl,--wrap=__cxa_throw' ]
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can_wrap_cxa_throw_result = cxx.run(
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can_wrap_cxa_throw_test_code,
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args : wrap_cxa_throw_args,
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include_directories : include_directories('.'),
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name : 'can wrap __cxa_throw (catches libstdc++ throws)',
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)
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can_wrap_cxa_throw = can_wrap_cxa_throw_result.compiled() and can_wrap_cxa_throw_result.returncode() == 0
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if can_wrap_cxa_throw
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wrap_cxa_throw_lib = static_library(
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'wrap-cxa-throw',
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'wrap-cxa-throw.cc',
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)
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cxa_throw_dep = declare_dependency(
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link_whole : wrap_cxa_throw_lib,
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link_args : wrap_cxa_throw_args + [ '-Wl,-u,__wrap___cxa_throw' ],
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)
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have_cxa_throw = true
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endif
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endif

‎nix-meson-build-support/common/cxa-throw/wrap-cxa-throw.cc‎

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#include <cstdlib>
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#include <typeinfo>
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#include "is-logic-error.hh"
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#ifndef CXA_THROW_ON_LOGIC_ERROR
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# define CXA_THROW_ON_LOGIC_ERROR() abort()
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#endif
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extern "C" void __real___cxa_throw(void *, std::type_info *, void (*)(void *));
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extern "C" void __wrap___cxa_throw(void * exc, std::type_info * tinfo, void (*dest)(void *))
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{
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if (is_logic_error(tinfo))
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CXA_THROW_ON_LOGIC_ERROR();
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__real___cxa_throw(exc, tinfo, dest);
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__builtin_unreachable();
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}

‎nix-meson-build-support/common/meson.build‎

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subdir('assert-fail')
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subdir('asan-options')
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subdir('cxa-throw')

‎src/libutil-tests/cxa-throw.cc‎

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#include <gtest/gtest.h>
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#include <stdexcept>
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#include <string>
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TEST(CxaThrow, catchesLogicErrorFromStdlib)
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{
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const char * volatile p = nullptr;
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ASSERT_DEATH({ std::string s(p); }, "");
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}
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TEST(CxaThrow, catchesLogicError)
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{
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ASSERT_DEATH({ throw std::logic_error("test"); }, "");
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}
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TEST(CxaThrow, catchesOutOfRange)
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{
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ASSERT_DEATH({ throw std::out_of_range("test"); }, "");
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}
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TEST(CxaThrow, catchesInvalidArgument)
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{
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ASSERT_DEATH({ throw std::invalid_argument("test"); }, "");
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}
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TEST(CxaThrow, catchesDomainError)
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{
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ASSERT_DEATH({ throw std::domain_error("test"); }, "");
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}
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TEST(CxaThrow, catchesLengthError)
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{
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ASSERT_DEATH({ throw std::length_error("test"); }, "");
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}

‎src/libutil-tests/meson.build‎

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'xml-writer.cc',
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)
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if have_cxa_throw
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sources += files('cxa-throw.cc')
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endif
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include_dirs = [ include_directories('.') ]
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‎src/libutil/meson.build‎

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subdir('nix-meson-build-support/common')
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if have_cxa_throw
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deps_other += cxa_throw_dep
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endif
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sources = [ config_priv_h ] + files(
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'archive.cc',
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'args.cc',

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