third_party/libcxx: Build with exceptions

Build libcxx with exceptions enabled.

- Removed `_LIBCPP_NO_EXCEPTIONS` from `__config`.
- Switched the exception implementation to `libcxxabi`. These two files
are taken from the same `libcxx` version as mentioned in `README.cosmo`.
- Removed `new_handler_fallback` in favor of `libcxxabi` implementation.
- Enable `-fexceptions` and `-frtti` for `libcxx`.
- Removed `THIRD_PARTY_LIBCXX` dependency from `libcxxabi` and
`libunwind`. These libraries do not use any runtime `libcxx` functions,
just headers.

Makefile

@@ -284,6 +284,8 @@ include third_party/stb/BUILD.mk		# │
 include third_party/mbedtls/BUILD.mk		# │
 include third_party/ncurses/BUILD.mk		# │
 include third_party/readline/BUILD.mk		# │
+include third_party/libunwind/BUILD.mk		# |
+include third_party/libcxxabi/BUILD.mk		# |
 include third_party/libcxx/BUILD.mk		# │
 include third_party/pcre/BUILD.mk		# │
 include third_party/less/BUILD.mk		# │
@@ -328,8 +330,6 @@ include third_party/python/BUILD.mk
 include tool/build/BUILD.mk
 include tool/curl/BUILD.mk
 include third_party/qemu/BUILD.mk
-include third_party/libunwind/BUILD.mk
-include third_party/libcxxabi/BUILD.mk
 include examples/BUILD.mk
 include examples/pyapp/BUILD.mk
 include examples/pylife/BUILD.mk

third_party/libcxx/BUILD.mk

@@ -70,8 +70,8 @@ THIRD_PARTY_LIBCXX_A_HDRS =					\
 	third_party/libcxx/deque				\
 	third_party/libcxx/errno.h				\
 	third_party/libcxx/exception				\
-	third_party/libcxx/exception_fallback.hh		\
+	third_party/libcxx/exception_libcxxabi.hh		\
-	third_party/libcxx/exception_pointer_unimplemented.hh	\
+	third_party/libcxx/exception_pointer_cxxabi.hh		\
 	third_party/libcxx/execution				\
 	third_party/libcxx/experimental/__config		\
 	third_party/libcxx/filesystem				\
@@ -99,7 +99,6 @@ THIRD_PARTY_LIBCXX_A_HDRS =					\
 	third_party/libcxx/memory				\
 	third_party/libcxx/mutex				\
 	third_party/libcxx/new					\
-	third_party/libcxx/new_handler_fallback.hh		\
 	third_party/libcxx/numeric				\
 	third_party/libcxx/optional				\
 	third_party/libcxx/ostream				\
@@ -200,7 +199,9 @@ THIRD_PARTY_LIBCXX_A_DIRECTDEPS =				\
 	LIBC_THREAD						\
 	LIBC_TINYMATH						\
 	THIRD_PARTY_COMPILER_RT					\
-	THIRD_PARTY_GDTOA
+	THIRD_PARTY_GDTOA					\
+	THIRD_PARTY_LIBCXXABI					\
+	THIRD_PARTY_LIBUNWIND
 
 THIRD_PARTY_LIBCXX_A_DEPS :=					\
 	$(call uniq,$(foreach x,$(THIRD_PARTY_LIBCXX_A_DIRECTDEPS),$($(x))))
@@ -217,7 +218,10 @@ $(THIRD_PARTY_LIBCXX_A).pkg:					\
 $(THIRD_PARTY_LIBCXX_A_OBJS): private				\
 		CXXFLAGS +=					\
 			-ffunction-sections			\
-			-fdata-sections
+			-fdata-sections				\
+			-fexceptions				\
+			-frtti					\
+			-DLIBCXX_BUILDING_LIBCXXABI
 
 THIRD_PARTY_LIBCXX_LIBS = $(foreach x,$(THIRD_PARTY_LIBCXX_ARTIFACTS),$($(x)))
 THIRD_PARTY_LIBCXX_SRCS = $(foreach x,$(THIRD_PARTY_LIBCXX_ARTIFACTS),$($(x)_SRCS))

third_party/libcxx/__config

@@ -12,7 +12,6 @@
 #include "libc/isystem/features.h"
 
 #define _LIBCPP_ABI_UNSTABLE
-#define _LIBCPP_NO_EXCEPTIONS
 #define _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
 #define _LIBCPP_DISABLE_DEPRECATION_WARNINGS
 #define _LIBCPP_HAS_TRIVIAL_MUTEX_DESTRUCTION

third_party/libcxx/exception.cc

@@ -11,6 +11,11 @@
 #include "third_party/libcxx/new"
 #include "third_party/libcxx/typeinfo"
 
-#include "third_party/libcxx/atomic_support.hh"
+#if defined(LIBCXXRT) || defined(LIBCXX_BUILDING_LIBCXXABI)
-#include "third_party/libcxx/exception_fallback.hh"
+  #include "third_party/libcxxabi/include/cxxabi.h"
-#include "third_party/libcxx/exception_pointer_unimplemented.hh"
+  using namespace __cxxabiv1;
+  #define HAVE_DEPENDENT_EH_ABI 1
+#endif
+
+#include "third_party/libcxx/exception_libcxxabi.hh"
+#include "third_party/libcxx/exception_pointer_cxxabi.hh"

third_party/libcxx/exception_fallback.hh

@@ -1,111 +0,0 @@
-// -*- C++ -*-
-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#include "third_party/libcxx/exception"
-#include "third_party/libcxx/cstdio"
-#include "third_party/libcxx/atomic_support.hh"
-
-namespace std {
-
-_LIBCPP_SAFE_STATIC static std::terminate_handler __terminate_handler;
-
-#if _LIBCPP_STD_VER <= 14 ||                                                   \
-    defined(_LIBCPP_ENABLE_CXX17_REMOVED_UNEXPECTED_FUNCTIONS) ||              \
-    defined(_LIBCPP_BUILDING_LIBRARY)
-_LIBCPP_SAFE_STATIC static std::unexpected_handler __unexpected_handler;
-// libcxxrt provides implementations of these functions itself.
-unexpected_handler set_unexpected(unexpected_handler func) _NOEXCEPT {
-  return __libcpp_atomic_exchange(&__unexpected_handler, func);
-}
-unexpected_handler get_unexpected() _NOEXCEPT {
-  return __libcpp_atomic_load(&__unexpected_handler);
-}
-_LIBCPP_NORETURN
-void unexpected() {
-  (*get_unexpected())();
-  // unexpected handler should not return
-  terminate();
-}
-#endif
-
-terminate_handler set_terminate(terminate_handler func) _NOEXCEPT {
-  return __libcpp_atomic_exchange(&__terminate_handler, func);
-}
-
-terminate_handler get_terminate() _NOEXCEPT {
-  return __libcpp_atomic_load(&__terminate_handler);
-}
-
-#ifndef __EMSCRIPTEN__ // We provide this in JS
-_LIBCPP_NORETURN
-void terminate() _NOEXCEPT {
-#ifndef _LIBCPP_NO_EXCEPTIONS
-  try {
-#endif // _LIBCPP_NO_EXCEPTIONS
-    (*get_terminate())();
-    // handler should not return
-    fprintf(stderr, "terminate_handler unexpectedly returned\n");
-    ::abort();
-#ifndef _LIBCPP_NO_EXCEPTIONS
-  } catch (...) {
-    // handler should not throw exception
-    fprintf(stderr, "terminate_handler unexpectedly threw an exception\n");
-    ::abort();
-  }
-#endif // _LIBCPP_NO_EXCEPTIONS
-}
-#endif // !__EMSCRIPTEN__
-
-#if !defined(__EMSCRIPTEN__)
-bool uncaught_exception() _NOEXCEPT { return uncaught_exceptions() > 0; }
-
-int uncaught_exceptions() _NOEXCEPT {
-  // #warning uncaught_exception not yet implemented
-  fprintf(stderr, "uncaught_exceptions not yet implemented\n");
-  ::abort();
-}
-#endif // !__EMSCRIPTEN__
-
-exception::~exception() _NOEXCEPT {}
-
-const char* exception::what() const _NOEXCEPT { return "std::exception"; }
-
-bad_exception::~bad_exception() _NOEXCEPT {}
-
-const char* bad_exception::what() const _NOEXCEPT {
-  return "std::bad_exception";
-}
-
-bad_alloc::bad_alloc() _NOEXCEPT {}
-
-bad_alloc::~bad_alloc() _NOEXCEPT {}
-
-const char* bad_alloc::what() const _NOEXCEPT { return "std::bad_alloc"; }
-
-bad_array_new_length::bad_array_new_length() _NOEXCEPT {}
-
-bad_array_new_length::~bad_array_new_length() _NOEXCEPT {}
-
-const char* bad_array_new_length::what() const _NOEXCEPT {
-  return "bad_array_new_length";
-}
-
-bad_cast::bad_cast() _NOEXCEPT {}
-
-bad_typeid::bad_typeid() _NOEXCEPT {}
-
-bad_cast::~bad_cast() _NOEXCEPT {}
-
-const char* bad_cast::what() const _NOEXCEPT { return "std::bad_cast"; }
-
-bad_typeid::~bad_typeid() _NOEXCEPT {}
-
-const char* bad_typeid::what() const _NOEXCEPT { return "std::bad_typeid"; }
-
-} // namespace std

third_party/libcxx/exception_libcxxabi.hh

@@ -7,20 +7,21 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "third_party/libcxx/__config"
+#include "third_party/libcxxabi/include/cxxabi.h"
-#include "third_party/libcxx/new"
+#include "third_party/libcxx/exception"
-#include "third_party/libcxx/atomic_support.hh"
+using namespace __cxxabiv1;
 
 namespace std {
 
-_LIBCPP_SAFE_STATIC static std::new_handler __new_handler;
+bool uncaught_exception() _NOEXCEPT { return uncaught_exceptions() > 0; }
 
-new_handler set_new_handler(new_handler handler) _NOEXCEPT {
+int uncaught_exceptions() _NOEXCEPT
-  return __libcpp_atomic_exchange(&__new_handler, handler);
+{
-}
+# if _LIBCPPABI_VERSION > 1001
-
+    return __cxa_uncaught_exceptions();
-new_handler get_new_handler() _NOEXCEPT {
+# else
-  return __libcpp_atomic_load(&__new_handler);
+    return __cxa_uncaught_exception() ? 1 : 0;
+# endif
 }
 
 } // namespace std

third_party/libcxx/exception_pointer_cxxabi.hh

@@ -0,0 +1,73 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "third_party/libcxxabi/include/cxxabi.h"
+#include "third_party/libcxx/exception"
+using namespace __cxxabiv1;
+
+namespace std {
+
+exception_ptr::~exception_ptr() _NOEXCEPT {
+  __cxa_decrement_exception_refcount(__ptr_);
+}
+
+exception_ptr::exception_ptr(const exception_ptr& other) _NOEXCEPT
+    : __ptr_(other.__ptr_)
+{
+    __cxa_increment_exception_refcount(__ptr_);
+}
+
+exception_ptr& exception_ptr::operator=(const exception_ptr& other) _NOEXCEPT
+{
+    if (__ptr_ != other.__ptr_)
+    {
+        __cxa_increment_exception_refcount(other.__ptr_);
+        __cxa_decrement_exception_refcount(__ptr_);
+        __ptr_ = other.__ptr_;
+    }
+    return *this;
+}
+
+nested_exception::nested_exception() _NOEXCEPT
+    : __ptr_(current_exception())
+{
+}
+
+nested_exception::~nested_exception() _NOEXCEPT
+{
+}
+
+_LIBCPP_NORETURN
+void
+nested_exception::rethrow_nested() const
+{
+    if (__ptr_ == nullptr)
+        terminate();
+    rethrow_exception(__ptr_);
+}
+
+exception_ptr current_exception() _NOEXCEPT
+{
+    // be nicer if there was a constructor that took a ptr, then
+    // this whole function would be just:
+    //    return exception_ptr(__cxa_current_primary_exception());
+    exception_ptr ptr;
+    ptr.__ptr_ = __cxa_current_primary_exception();
+    return ptr;
+}
+
+_LIBCPP_NORETURN
+void rethrow_exception(exception_ptr p)
+{
+    __cxa_rethrow_primary_exception(p.__ptr_);
+    // if p.__ptr_ is NULL, above returns so we terminate
+    terminate();
+}
+
+} // namespace std

third_party/libcxx/exception_pointer_unimplemented.hh

@@ -1,68 +0,0 @@
-// -*- C++ -*-
-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#include "third_party/libcxx/stdio.h"
-#include "third_party/libcxx/stdlib.h"
-#include "third_party/libcxx/exception"
-
-namespace std {
-
-exception_ptr::~exception_ptr() _NOEXCEPT {
-  // #warning exception_ptr not yet implemented
-  fprintf(stderr, "exception_ptr not yet implemented\n");
-  ::abort();
-}
-
-exception_ptr::exception_ptr(const exception_ptr& other) _NOEXCEPT
-    : __ptr_(other.__ptr_) {
-  // #warning exception_ptr not yet implemented
-  fprintf(stderr, "exception_ptr not yet implemented\n");
-  ::abort();
-}
-
-exception_ptr& exception_ptr::operator=(const exception_ptr& other) _NOEXCEPT {
-  // #warning exception_ptr not yet implemented
-  fprintf(stderr, "exception_ptr not yet implemented\n");
-  ::abort();
-}
-
-nested_exception::nested_exception() _NOEXCEPT : __ptr_(current_exception()) {}
-
-#if !defined(__GLIBCXX__)
-
-nested_exception::~nested_exception() _NOEXCEPT {}
-
-#endif
-
-_LIBCPP_NORETURN
-void nested_exception::rethrow_nested() const {
-  // #warning exception_ptr not yet implemented
-  fprintf(stderr, "exception_ptr not yet implemented\n");
-  ::abort();
-#if 0
-  if (__ptr_ == nullptr)
-      terminate();
-  rethrow_exception(__ptr_);
-#endif // FIXME
-}
-
-exception_ptr current_exception() _NOEXCEPT {
-  // #warning exception_ptr not yet implemented
-  fprintf(stderr, "exception_ptr not yet implemented\n");
-  ::abort();
-}
-
-_LIBCPP_NORETURN
-void rethrow_exception(exception_ptr p) {
-  // #warning exception_ptr not yet implemented
-  fprintf(stderr, "exception_ptr not yet implemented\n");
-  ::abort();
-}
-
-} // namespace std

third_party/libcxx/new.cc

@@ -10,7 +10,7 @@
 
 #include "third_party/libcxx/new"
 #include "third_party/libcxx/atomic_support.hh"
-#include "third_party/libcxx/new_handler_fallback.hh"
+#include "third_party/libcxxabi/include/cxxabi.h"
 
 namespace std {
 

third_party/libcxxabi/BUILD.mk

@@ -66,7 +66,6 @@ THIRD_PARTY_LIBCXXABI_A_DIRECTDEPS =					\
 	LIBC_STDIO							\
 	LIBC_STR							\
 	LIBC_THREAD							\
-	THIRD_PARTY_LIBCXX						\
 	THIRD_PARTY_LIBUNWIND
 
 THIRD_PARTY_LIBCXXABI_A_DEPS :=						\

third_party/libunwind/BUILD.mk

@@ -54,8 +54,7 @@ THIRD_PARTY_LIBUNWIND_A_CHECKS =					\
 THIRD_PARTY_LIBUNWIND_A_DIRECTDEPS =					\
 	LIBC_CALLS							\
 	LIBC_INTRIN							\
-	LIBC_STDIO							\
+	LIBC_STDIO
-	THIRD_PARTY_LIBCXX
 
 THIRD_PARTY_LIBUNWIND_A_DEPS :=						\
 	$(call uniq,$(foreach x,$(THIRD_PARTY_LIBUNWIND_A_DIRECTDEPS),$($(x))))