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-rw-r--r--build/unix/stdc++compat/hide_std.ld5
-rw-r--r--build/unix/stdc++compat/moz.build24
-rw-r--r--build/unix/stdc++compat/stdc++compat.cpp196
3 files changed, 225 insertions, 0 deletions
diff --git a/build/unix/stdc++compat/hide_std.ld b/build/unix/stdc++compat/hide_std.ld
new file mode 100644
index 0000000000..4b3400b0f3
--- /dev/null
+++ b/build/unix/stdc++compat/hide_std.ld
@@ -0,0 +1,5 @@
+hidden {
+ local:
+ # std::thread::_M_start_thread(...)
+ _ZNSt6thread15_M_start_thread*;
+};
diff --git a/build/unix/stdc++compat/moz.build b/build/unix/stdc++compat/moz.build
new file mode 100644
index 0000000000..a3681d15d8
--- /dev/null
+++ b/build/unix/stdc++compat/moz.build
@@ -0,0 +1,24 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+if CONFIG["OS_TARGET"] == "Linux":
+ Library("stdc++compat")
+ SOURCES += ["stdc++compat.cpp"]
+
+if CONFIG["HOST_OS_ARCH"] == "Linux":
+ HostLibrary("host_stdc++compat")
+ HOST_SOURCES += [
+ "stdc++compat.cpp",
+ ]
+
+FORCE_STATIC_LIB = True
+
+NO_PGO = True
+
+DisableStlWrapping()
+COMPILE_FLAGS["CLANG_PLUGIN"] = []
+
+OS_LIBS += ["-Wl,--version-script,%s/hide_std.ld" % SRCDIR]
diff --git a/build/unix/stdc++compat/stdc++compat.cpp b/build/unix/stdc++compat/stdc++compat.cpp
new file mode 100644
index 0000000000..0180f6bcfa
--- /dev/null
+++ b/build/unix/stdc++compat/stdc++compat.cpp
@@ -0,0 +1,196 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <ostream>
+#include <istream>
+#include <sstream>
+#include <memory>
+#include <string>
+#include <stdarg.h>
+#include <stdio.h>
+#include <mozilla/Assertions.h>
+#include <cxxabi.h>
+
+/*
+ GLIBCXX_3.4.19 is from gcc 4.8.1 (199309)
+ GLIBCXX_3.4.20 is from gcc 4.9.0 (199307)
+ GLIBCXX_3.4.21 is from gcc 5.0 (210290)
+ GLIBCXX_3.4.22 is from gcc 6.0 (222482)
+ GLIBCXX_3.4.23 is from gcc 7
+ GLIBCXX_3.4.24 is from gcc 8
+ GLIBCXX_3.4.25 is from gcc 8
+ GLIBCXX_3.4.26 is from gcc 9
+ GLIBCXX_3.4.27 is from gcc 10
+ GLIBCXX_3.4.28 is from gcc 10
+ GLIBCXX_3.4.29 is from gcc 11
+
+This file adds the necessary compatibility tricks to avoid symbols with
+version GLIBCXX_3.4.20 and bigger, keeping binary compatibility with
+libstdc++ 4.8.1.
+
+WARNING: all symbols from this file must be defined weak when they
+overlap with libstdc++.
+*/
+
+namespace std {
+
+/* We shouldn't be throwing exceptions at all, but it sadly turns out
+ we call STL (inline) functions that do. This avoids the GLIBCXX_3.4.20
+ symbol version. */
+void __attribute__((weak)) __throw_out_of_range_fmt(char const* fmt, ...) {
+ va_list ap;
+ char buf[1024]; // That should be big enough.
+
+ va_start(ap, fmt);
+ vsnprintf(buf, sizeof(buf), fmt, ap);
+ buf[sizeof(buf) - 1] = 0;
+ va_end(ap);
+
+ __throw_range_error(buf);
+}
+
+} // namespace std
+
+namespace __cxxabiv1 {
+/* Calls to this function are added by the compiler itself on `new Class[n]`
+ * calls. This avoids the GLIBCXX_3.4.20 symbol version. */
+extern "C" void __attribute__((weak)) __cxa_throw_bad_array_new_length() {
+ MOZ_CRASH();
+}
+} // namespace __cxxabiv1
+
+#if _GLIBCXX_RELEASE >= 11
+namespace std {
+
+/* This avoids the GLIBCXX_3.4.29 symbol version. */
+void __attribute__((weak)) __throw_bad_array_new_length() { MOZ_CRASH(); }
+
+} // namespace std
+#endif
+
+/* While we generally don't build with exceptions, we have some host tools
+ * that do use them. libstdc++ from GCC 5.0 added exception constructors with
+ * char const* argument. Older versions only have a constructor with
+ * std::string. This avoids the GLIBCXX_3.4.21 symbol version. */
+namespace std {
+__attribute__((weak)) runtime_error::runtime_error(char const* s)
+ : runtime_error(std::string(s)) {}
+__attribute__((weak)) out_of_range::out_of_range(char const* s)
+ : out_of_range(std::string(s)) {}
+__attribute__((weak)) invalid_argument::invalid_argument(char const* s)
+ : invalid_argument(std::string(s)) {}
+} // namespace std
+
+/* Expose the definitions for the old ABI, allowing us to call its functions */
+#define _GLIBCXX_THREAD_ABI_COMPAT 1
+#include <thread>
+
+namespace std {
+/* The old ABI has a thread::_M_start_thread(shared_ptr<_Impl_base>),
+ * while the new has thread::_M_start_thread(unique_ptr<_State>, void(*)()).
+ * There is an intermediate ABI at version 3.4.21, with
+ * thread::_M_start_thread(shared_ptr<_Impl_base>, void(*)()).
+ * The void(*)() parameter is only there to keep a reference to pthread_create
+ * on the caller side, and is unused in the implementation
+ * We're creating an entry point for the new and intermediate ABIs, and make
+ * them call the old ABI. This avoids the GLIBCXX_3.4.21 symbol version. */
+__attribute__((weak)) void thread::_M_start_thread(shared_ptr<_Impl_base> impl,
+ void (*)()) {
+ _M_start_thread(std::move(impl));
+}
+
+/* We need a _Impl_base-derived class wrapping a _State to call the old ABI
+ * from what we got by diverting the new API. This avoids the GLIBCXX_3.4.22
+ * symbol version. */
+struct StateWrapper : public thread::_Impl_base {
+ unique_ptr<thread::_State> mState;
+
+ StateWrapper(unique_ptr<thread::_State> aState) : mState(std::move(aState)) {}
+
+ void _M_run() override { mState->_M_run(); }
+};
+
+/* This avoids the GLIBCXX_3.4.22 symbol version. */
+__attribute__((weak)) void thread::_M_start_thread(unique_ptr<_State> aState,
+ void (*)()) {
+ auto impl = std::make_shared<StateWrapper>(std::move(aState));
+ _M_start_thread(std::move(impl));
+}
+
+/* For some reason this is a symbol exported by new versions of libstdc++,
+ * even though the destructor is default there too. This avoids the
+ * GLIBCXX_3.4.22 symbol version. */
+__attribute__((weak)) thread::_State::~_State() = default;
+
+#if _GLIBCXX_RELEASE >= 9
+// Ideally we'd define
+// bool _Sp_make_shared_tag::_S_eq(const type_info& ti) noexcept
+// but we wouldn't be able to change its visibility because of the existing
+// definition in C++ headers. We do need to change its visibility because we
+// don't want it to be shadowing the one provided by libstdc++ itself, because
+// it doesn't support RTTI. Not supporting RTTI doesn't matter for Firefox
+// itself because it's built with RTTI disabled.
+// So we define via the mangled symbol.
+// This avoids the GLIBCXX_3.4.26 symbol version.
+extern "C" __attribute__((visibility("hidden"))) bool
+_ZNSt19_Sp_make_shared_tag5_S_eqERKSt9type_info(const type_info*) noexcept {
+ return false;
+}
+#endif
+
+} // namespace std
+
+namespace std {
+/* Instantiate this template to avoid GLIBCXX_3.4.21 symbol versions
+ * depending on optimization level */
+template basic_ios<char, char_traits<char>>::operator bool() const;
+} // namespace std
+
+#if !defined(MOZ_ASAN) && !defined(MOZ_TSAN)
+/* operator delete with size is only available in CXXAPI_1.3.9, equivalent to
+ * GLIBCXX_3.4.21. */
+void operator delete(void* ptr, size_t size) noexcept(true) {
+ ::operator delete(ptr);
+}
+#endif
+
+namespace std {
+/* Instantiate this template to avoid GLIBCXX_3.4.23 symbol versions
+ * depending on optimization level */
+template basic_string<char, char_traits<char>, allocator<char>>::basic_string(
+ const basic_string&, size_t, const allocator<char>&);
+
+#if _GLIBCXX_RELEASE >= 9
+// This avoids the GLIBCXX_3.4.26 symbol version.
+template basic_stringstream<char, char_traits<char>,
+ allocator<char>>::basic_stringstream();
+
+template basic_ostringstream<char, char_traits<char>,
+ allocator<char>>::basic_ostringstream();
+#endif
+
+#if _GLIBCXX_RELEASE >= 11
+// This avoids the GLIBCXX_3.4.29 symbol version.
+template void basic_string<char, char_traits<char>, allocator<char>>::reserve();
+
+template void
+basic_string<wchar_t, char_traits<wchar_t>, allocator<wchar_t>>::reserve();
+#endif
+
+} // namespace std
+
+/* The __cxa_thread_atexit_impl symbol is only available on GLIBC 2.18, but we
+ * want things to keep working on 2.17. It's not actually used directly from
+ * C++ code, but through __cxa_thead_atexit in libstdc++. The problem we have,
+ * though, is that rust's libstd also uses it, introducing a dependency we
+ * don't actually want. Fortunately, we can fall back to libstdc++'s wrapper
+ * (which, on systems without __cxa_thread_atexit_impl, has its own compatible
+ * implementation).
+ * The __cxa_thread_atexit symbol itself is marked CXXABI_1.3.7, which is
+ * equivalent to GLIBCXX_3.4.18.
+ */
+extern "C" int __cxa_thread_atexit_impl(void (*dtor)(void*), void* obj,
+ void* dso_handle) {
+ return __cxxabiv1::__cxa_thread_atexit(dtor, obj, dso_handle);
+}