string/memory functions: avoid qemu bugs/performance issues.
Use V on real hardware, but GC on qemu.
Change-Id: I419546d94555540e14a14dcc52bd99413cbbcfa1
diff --git a/libc/arch-riscv64/dynamic_function_dispatch.cpp b/libc/arch-riscv64/dynamic_function_dispatch.cpp
new file mode 100644
index 0000000..24fafe7
--- /dev/null
+++ b/libc/arch-riscv64/dynamic_function_dispatch.cpp
@@ -0,0 +1,146 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * 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 OWNER 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 <fcntl.h>
+#include <stddef.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+#include <private/bionic_ifuncs.h>
+
+extern "C" {
+
+static __always_inline int ifunc_faccessat(int dir_fd, const char* path, int mode) {
+ register long a0 __asm__("a0") = dir_fd;
+ register long a1 __asm__("a1") = reinterpret_cast<long>(path);
+ register long a2 __asm__("a2") = mode;
+ register long a7 __asm__("a7") = __NR_faccessat;
+ __asm__("ecall" : "=r"(a0) : "r"(a0), "r"(a1), "r"(a2), "r"(a7) : "memory");
+ return a0;
+}
+
+static bool have_fast_v() {
+ static bool result = []() {
+ // We don't want to do a full "bogomips" test, so just check for the
+ // presence of a file that would indicate that we're running in qemu.
+ return ifunc_faccessat(AT_FDCWD, "/dev/hvc0", F_OK) == 0;
+ }();
+ return result;
+}
+
+typedef void* memchr_func(const void*, int, size_t);
+DEFINE_IFUNC_FOR(memchr) {
+ if (have_fast_v()) RETURN_FUNC(memchr_func, memchr_v);
+ RETURN_FUNC(memchr_func, memchr_gc);
+}
+
+typedef int memcmp_func(const void*, const void*, size_t);
+DEFINE_IFUNC_FOR(memcmp) {
+ if (have_fast_v()) RETURN_FUNC(memcmp_func, memcmp_v);
+ RETURN_FUNC(memcmp_func, memcmp_gc);
+}
+
+typedef void* memcpy_func(void*, const void*, size_t);
+DEFINE_IFUNC_FOR(memcpy) {
+ if (have_fast_v()) RETURN_FUNC(memcpy_func, memcpy_v);
+ RETURN_FUNC(memcpy_func, memcpy_gc);
+}
+
+typedef void* memmove_func(void*, const void*, size_t);
+DEFINE_IFUNC_FOR(memmove) {
+ if (have_fast_v()) RETURN_FUNC(memmove_func, memmove_v);
+ RETURN_FUNC(memmove_func, memmove_gc);
+}
+
+typedef void* memset_func(void*, int, size_t);
+DEFINE_IFUNC_FOR(memset) {
+ if (have_fast_v()) RETURN_FUNC(memset_func, memset_v);
+ RETURN_FUNC(memset_func, memset_gc);
+}
+
+typedef char* stpcpy_func(char*, const char*);
+DEFINE_IFUNC_FOR(stpcpy) {
+ if (have_fast_v()) RETURN_FUNC(stpcpy_func, stpcpy_v);
+ RETURN_FUNC(stpcpy_func, stpcpy_gc);
+}
+
+typedef char* strcat_func(char*, const char*);
+DEFINE_IFUNC_FOR(strcat) {
+ if (have_fast_v()) RETURN_FUNC(strcat_func, strcat_v);
+ RETURN_FUNC(strcat_func, strcat_gc);
+}
+
+typedef char* strchr_func(const char*, int);
+DEFINE_IFUNC_FOR(strchr) {
+ if (have_fast_v()) RETURN_FUNC(strchr_func, strchr_v);
+ RETURN_FUNC(strchr_func, strchr_gc);
+}
+
+typedef int strcmp_func(const char*, const char*);
+DEFINE_IFUNC_FOR(strcmp) {
+ if (have_fast_v()) RETURN_FUNC(strcmp_func, strcmp_v);
+ RETURN_FUNC(strcmp_func, strcmp_gc);
+}
+
+typedef char* strcpy_func(char*, const char*);
+DEFINE_IFUNC_FOR(strcpy) {
+ if (have_fast_v()) RETURN_FUNC(strcpy_func, strcpy_v);
+ RETURN_FUNC(strcpy_func, strcpy_gc);
+}
+
+typedef size_t strlen_func(const char*);
+DEFINE_IFUNC_FOR(strlen) {
+ if (have_fast_v()) RETURN_FUNC(strlen_func, strlen_v);
+ RETURN_FUNC(strlen_func, strlen_gc);
+}
+
+typedef char* strncat_func(char*, const char*, size_t);
+DEFINE_IFUNC_FOR(strncat) {
+ if (have_fast_v()) RETURN_FUNC(strncat_func, strncat_v);
+ RETURN_FUNC(strncat_func, strncat_gc);
+}
+
+typedef int strncmp_func(const char*, const char*, size_t);
+DEFINE_IFUNC_FOR(strncmp) {
+ if (have_fast_v()) RETURN_FUNC(strncmp_func, strncmp_v);
+ RETURN_FUNC(strncmp_func, strncmp_gc);
+}
+
+typedef char* strncpy_func(char*, const char*, size_t);
+DEFINE_IFUNC_FOR(strncpy) {
+ if (have_fast_v()) RETURN_FUNC(strncpy_func, strncpy_v);
+ RETURN_FUNC(strncpy_func, strncpy_gc);
+}
+
+typedef size_t strnlen_func(const char*, size_t);
+DEFINE_IFUNC_FOR(strnlen) {
+ if (have_fast_v()) RETURN_FUNC(strnlen_func, strnlen_v);
+ RETURN_FUNC(strnlen_func, strnlen_gc);
+}
+
+} // extern "C"