Move libstdc++ into libc.
The Android build system always links against libstdc++.so anyway. Having
operator new and operator delete in a separate library means we can't use
constructors and destructors on heap-allocated objects inside the C library,
which is quite an unfortunate limitation.
This will be cheaper too; on LP64 we can stop linking against the [now empty]
libstdc++.so giving the dynamic linker one less library to worry about for
every process.
There's precedent too --- we already have no libpthread or librt.
For now I'm leaving the include files where they are, and I'm generating a
dummy libstdc++.so and libstdc++.a. We can come back and clean that up later
if all goes well.
Bug: 13367666
Change-Id: I6f3e27ea7c30d03d6394965d0400c9dc87fa83db
diff --git a/libc/bionic/__cxa_guard.cpp b/libc/bionic/__cxa_guard.cpp
new file mode 100644
index 0000000..5b0d57d
--- /dev/null
+++ b/libc/bionic/__cxa_guard.cpp
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2006 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stddef.h>
+#include <endian.h>
+
+#include "private/bionic_atomic_inline.h"
+#include "private/bionic_futex.h"
+
+// This file contains C++ ABI support functions for one time
+// constructors as defined in the "Run-time ABI for the ARM Architecture"
+// section 4.4.2
+//
+// ARM C++ ABI and Itanium/x86 C++ ABI has different definition for
+// one time construction:
+//
+// ARM C++ ABI defines the LSB of guard variable should be tested
+// by compiler-generated code before calling __cxa_guard_acquire et al.
+//
+// The Itanium/x86 C++ ABI defines the low-order _byte_ should be
+// tested instead.
+//
+// Meanwhile, guard variable are 32bit aligned for ARM, and 64bit
+// aligned for x86.
+//
+// Reference documentation:
+//
+// section 3.2.3 of ARM IHI 0041C (for ARM)
+// section 3.3.2 of the Itanium C++ ABI specification v1.83 (for x86).
+//
+// There is no C++ ABI available for other ARCH. But the gcc source
+// shows all other ARCH follow the definition of Itanium/x86 C++ ABI.
+
+#if defined(__arm__)
+// The ARM C++ ABI mandates that guard variables are 32-bit aligned, 32-bit
+// values. The LSB is tested by the compiler-generated code before calling
+// __cxa_guard_acquire.
+union _guard_t {
+ int volatile state;
+ int32_t aligner;
+};
+
+const static int ready = 0x1;
+const static int pending = 0x2;
+const static int waiting = 0x6;
+
+#else
+// The Itanium/x86 C++ ABI (used by all other architectures) mandates that
+// guard variables are 64-bit aligned, 64-bit values. The LSB is tested by
+// the compiler-generated code before calling __cxa_guard_acquire.
+union _guard_t {
+ int volatile state;
+ int64_t aligner;
+};
+
+const static int ready = letoh32(0x1);
+const static int pending = letoh32(0x100);
+const static int waiting = letoh32(0x10000);
+#endif
+
+extern "C" int __cxa_guard_acquire(_guard_t* gv) {
+ // 0 -> pending, return 1
+ // pending -> waiting, wait and return 0
+ // waiting: untouched, wait and return 0
+ // ready: untouched, return 0
+
+retry:
+ if (__bionic_cmpxchg(0, pending, &gv->state) == 0) {
+ ANDROID_MEMBAR_FULL();
+ return 1;
+ }
+ __bionic_cmpxchg(pending, waiting, &gv->state); // Indicate there is a waiter
+ __futex_wait(&gv->state, waiting, NULL);
+
+ if (gv->state != ready) {
+ // __cxa_guard_abort was called, let every thread try since there is no return code for this condition
+ goto retry;
+ }
+
+ ANDROID_MEMBAR_FULL();
+ return 0;
+}
+
+extern "C" void __cxa_guard_release(_guard_t* gv) {
+ // pending -> ready
+ // waiting -> ready, and wake
+
+ ANDROID_MEMBAR_FULL();
+ if (__bionic_cmpxchg(pending, ready, &gv->state) == 0) {
+ return;
+ }
+
+ gv->state = ready;
+ __futex_wake(&gv->state, 0x7fffffff);
+}
+
+extern "C" void __cxa_guard_abort(_guard_t* gv) {
+ ANDROID_MEMBAR_FULL();
+ gv->state= 0;
+ __futex_wake(&gv->state, 0x7fffffff);
+}