Revert "LibC: Implement Itanium C++ ABI for static variable guards"

This reverts commit cdbbe14062.

Libraries/CMakeLists.txt

@@ -2,7 +2,6 @@ add_subdirectory(LibAudio)
 add_subdirectory(LibC)
 add_subdirectory(LibCore)
 add_subdirectory(LibCrypto)
-add_subdirectory(LibCxx)
 add_subdirectory(LibDebug)
 add_subdirectory(LibDesktop)
 add_subdirectory(LibGemini)

Libraries/LibC/CMakeLists.txt

@@ -3,7 +3,7 @@ set(LIBC_SOURCES
     assert.cpp
     crt0.cpp
     ctype.cpp
-    cxaatexit.cpp
+    cxxabi.cpp
     dirent.cpp
     dlfcn.cpp
     fcntl.cpp
@@ -51,6 +51,8 @@ file(GLOB AK_SOURCES "../../AK/*.cpp")
 file(GLOB ELF_SOURCES "../LibELF/*.cpp")
 set(ELF_SOURCES ${ELF_SOURCES} ../LibELF/Arch/i386/plt_trampoline.S)
 
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DSERENITY_LIBC_BUILD")
+
 add_library(crt0 STATIC crt0.cpp)
 add_custom_command(
     TARGET crt0
@@ -60,4 +62,4 @@ add_custom_command(
 set(SOURCES ${LIBC_SOURCES} ${AK_SOURCES} ${ELF_SOURCES})
 serenity_libc(LibC c)
 target_link_libraries(LibC crt0)
-add_dependencies(LibC LibM LibCxx)
+add_dependencies(LibC LibM)

Libraries/LibC/cxxabi.cpp

@@ -25,6 +25,7 @@
  */
 
 #include <AK/Types.h>
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 

Libraries/LibCxx/CMakeLists.txt

@@ -1,7 +0,0 @@
-set(SOURCES
-    CxaGuard.cpp
-)
-
-# Shhh don't worry gcc, we are totally libstdc++
-serenity_libc(LibCxx stdc++)
-target_link_libraries(LibCxx LibC)

Libraries/LibCxx/CxaGuard.cpp

@@ -1,148 +0,0 @@
-/*
- * Copyright (c) 2020, Andrew Kaster <andrewdkaster@gmail.com>
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice, this
- *    list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright notice,
- *    this list of conditions and the following disclaimer in the documentation
- *    and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
- * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#include <AK/Atomic.h>
-#include <serenity.h>
-#include <stdint.h>
-#include <sys/types.h>
-
-// Static variable guard logic, using futexes
-// Written while looking at libc++ from a distance ;) This is super tricky...
-// From itanium spec: Get passed a pointer to a 64 bit guard "object"
-// [ 1 guard byte (checked by compiler), 7 bytes to work with  ]
-class CxaGuard {
-public:
-    enum GuardState : uint8_t {
-        NotInitialized = 0,
-        DoneInit = 1,
-        InitInProgress = 2,
-        WaitingOnInit = 4
-    };
-
-    CxaGuard(uint64_t* guard_pointer)
-        : m_full_guard_var(guard_pointer)
-        , m_compiler_guard_byte((uint8_t*)guard_pointer)
-        , m_local_state_byte(&((uint8_t*)guard_pointer)[1])
-    {
-    }
-
-    int acquire()
-    {
-        // Someone else already initailzied this by storing to the 'really done' slot
-        if (GuardState::NotInitialized != m_compiler_guard_byte.load(AK::memory_order_acquire))
-            return 0;
-
-        // Time to begin the waiting game..
-        while (true) {
-            // Try to claim initialization for this thread from the initial state
-            uint8_t last_state = GuardState::NotInitialized;
-            if (m_local_state_byte.compare_exchange_strong(last_state, GuardState::InitInProgress, AK::memory_order_acq_rel))
-                return 1; // Tell compiler-generated code to init the variable
-
-            // Someone else set the state to done, we're done here
-            if (last_state == DoneInit)
-                return 0;
-
-            // Someone else set InitInProgress, time to wait (maybe)
-            if (last_state & GuardState::InitInProgress) {
-                // Try to set the in progress + done bits
-                if ((last_state & GuardState::WaitingOnInit) == 0) {
-                    if (!m_local_state_byte.compare_exchange_strong(last_state, (GuardState::InitInProgress | GuardState::WaitingOnInit), AK::memory_order_acq_rel)) {
-                        if (last_state == GuardState::DoneInit)
-                            return 0;
-                        if (last_state == GuardState::NotInitialized)
-                            continue; // start over, and try to initialize in this thread
-                        // else wait, someone else set the wait bit before us
-                    }
-                }
-                // State is InitInProgress | WaitingOnInit, time to sleep
-                wait_on_futex();
-            }
-        }
-    }
-
-    void release()
-    {
-        // Store the value the compiler will look at, we're done! yay
-        m_compiler_guard_byte.store(GuardState::DoneInit, AK::memory_order_release);
-
-        // Set the value other threads chilling in our loop will look at to done
-        uint8_t old_local_state = m_local_state_byte.exchange(GuardState::DoneInit, AK::memory_order_acq_rel);
-
-        // Wake up sleepy heads, the variable is initialized!
-        if (old_local_state & GuardState::WaitingOnInit)
-            wake_futex();
-    }
-
-    void abort()
-    {
-        uint8_t old_local_state = m_local_state_byte.exchange(GuardState::NotInitialized, AK::memory_order_acq_rel);
-
-        // Wake up sleepy heads, someone else gets to try...
-        if (old_local_state & GuardState::WaitingOnInit)
-            wake_futex();
-    }
-
-private:
-    void wait_on_futex()
-    {
-        int futex_value = (GuardState::InitInProgress | GuardState::WaitingOnInit) << 8;
-        futex((int32_t*)m_full_guard_var, FUTEX_WAIT, futex_value, nullptr);
-    }
-
-    void wake_futex()
-    {
-        futex((int32_t*)m_full_guard_var, FUTEX_WAKE, INT32_MAX, nullptr);
-    }
-
-    void* m_full_guard_var;
-    AtomicRef<uint8_t> m_compiler_guard_byte;
-    AtomicRef<uint8_t> m_local_state_byte; // we'll load and set this atomically
-
-    // Note that we're not using 6/8 bytes of the guard object...
-};
-
-extern "C" {
-
-int __cxa_guard_acquire(uint64_t* guard_object)
-{
-    CxaGuard g(guard_object);
-    return g.acquire();
-}
-
-void __cxa_guard_release(uint64_t* guard_object)
-{
-    CxaGuard g(guard_object);
-    g.release();
-}
-
-void __cxa_guard_abort(uint64_t* guard_object)
-{
-    CxaGuard g(guard_object);
-    g.abort();
-}
-
-} // extern "C"

Toolchain/BuildIt.sh

@@ -230,7 +230,7 @@ pushd "$DIR/Build/"
         pushd "$BUILD"
             cmake ..
             "$MAKE" LibC
-            install -D Libraries/LibC/libc.a Libraries/LibM/libm.a Libraries/LibCxx/libstdc++.a Root/usr/lib/
+            install -D Libraries/LibC/libc.a Libraries/LibM/libm.a Root/usr/lib/
             SRC_ROOT=$(realpath "$DIR"/..)
             for header in "$SRC_ROOT"/Libraries/Lib{C,M}/**/*.h; do
                 target=$(echo "$header" | sed -e "s@$SRC_ROOT/Libraries/LibC@@" -e "s@$SRC_ROOT/Libraries/LibM@@")
@@ -239,6 +239,11 @@ pushd "$DIR/Build/"
             unset SRC_ROOT
         popd
 
+        echo "XXX build libstdc++"
+        "$MAKE" all-target-libstdc++-v3 || exit 1
+        echo "XXX install libstdc++"
+        "$MAKE" install-target-libstdc++-v3 || exit 1
+
         if [ "$(uname -s)" = "OpenBSD" ]; then
             cd "$DIR/Local/libexec/gcc/i686-pc-serenity/$GCC_VERSION" && ln -sf liblto_plugin.so.0.0 liblto_plugin.so
         fi