Change memcpy ifunc to return memmove for x86

It is cleaner to do this with ifunc. This is a partial revert of:
https://android-review.googlesource.com/c/platform/bionic/+/693863

Test: run bionic unit test
Change-Id: I5fb5745fc98807805aedb94b683e959e2a76a25d

libc/Android.bp

@@ -1171,7 +1171,7 @@ cc_library_static {
                 "arch-x86/atom/string/sse2-memset-atom.S",
                 "arch-x86/atom/string/sse2-strlen-atom.S",
                 "arch-x86/atom/string/ssse3-memcmp-atom.S",
-                "arch-x86/atom/string/ssse3-memcpy-atom.S",
+                "arch-x86/atom/string/ssse3-memmove-atom.S",
                 "arch-x86/atom/string/ssse3-strcpy-atom.S",
                 "arch-x86/atom/string/ssse3-strncpy-atom.S",
                 "arch-x86/atom/string/ssse3-wmemcmp-atom.S",

libc/arch-x86/atom/string/ssse3-memcpy-atom.S

@@ -34,10 +34,6 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 # define MEMCPY	memcpy_atom
 #endif
 
-#ifndef USE_AS_MEMMOVE
-# define USE_AS_MEMMOVE
-#endif
-
 #ifndef L
 # define L(label)	.L##label
 #endif
@@ -71,12 +67,6 @@ name:		\
 	cfi_startproc
 #endif
 
-#ifndef ALIAS_SYMBOL
-# define ALIAS_SYMBOL(alias, original) \
-	.globl alias; \
-	.equ alias, original
-#endif
-
 #ifndef END
 # define END(name)		\
 	cfi_endproc;		\
@@ -3132,5 +3122,3 @@ L(bk_ssse3_cpy):
 #endif
 
 END (MEMCPY)
-
-ALIAS_SYMBOL(memmove_atom, MEMCPY)

libc/arch-x86/atom/string/ssse3-memmove-atom.S

@@ -0,0 +1,34 @@
+/*
+Copyright (c) 2010, Intel Corporation
+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.
+
+    * Neither the name of Intel Corporation nor the names of its contributors
+    * may be used to endorse or promote products derived from this software
+    * without specific prior written permission.
+
+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.
+*/
+
+
+#define MEMCPY memmove_atom
+#define USE_AS_MEMMOVE
+#include "ssse3-memcpy-atom.S"

libc/arch-x86/dynamic_function_dispatch.cpp

@@ -93,13 +93,6 @@ DEFINE_IFUNC_FOR(__memset_chk) {
     RETURN_FUNC(__memset_chk_func, __memset_chk_generic);
 }
 
-typedef void* memcpy_func(void*, const void*, size_t);
-DEFINE_IFUNC_FOR(memcpy) {
-    __builtin_cpu_init();
-    if (cpu_is(ATOM)) RETURN_FUNC(memcpy_func, memcpy_atom);
-    RETURN_FUNC(memcpy_func, memcpy_generic);
-}
-
 typedef void* memmove_func(void* __dst, const void* __src, size_t __n);
 DEFINE_IFUNC_FOR(memmove) {
     __builtin_cpu_init();
@@ -107,6 +100,11 @@ DEFINE_IFUNC_FOR(memmove) {
     RETURN_FUNC(memmove_func, memmove_generic);
 }
 
+typedef void* memcpy_func(void*, const void*, size_t);
+DEFINE_IFUNC_FOR(memcpy) {
+    return memmove_resolver();
+}
+
 typedef char* strcpy_func(char* __dst, const char* __src);
 DEFINE_IFUNC_FOR(strcpy) {
     __builtin_cpu_init();

libc/arch-x86/silvermont/string/sse2-memmove-slm.S

@@ -67,12 +67,6 @@ name:		\
 	cfi_startproc
 #endif
 
-#ifndef ALIAS_SYMBOL
-# define ALIAS_SYMBOL(alias, original) \
-	.globl alias; \
-	.equ alias, original
-#endif
-
 #ifndef END
 # define END(name)		\
 	cfi_endproc;		\
@@ -543,5 +537,3 @@ L(mm_large_page_loop_backward):
 	jmp	L(mm_recalc_len)
 
 END (MEMMOVE)
-
-ALIAS_SYMBOL(memcpy_generic, MEMMOVE)

libc/arch-x86/static_function_dispatch.S

@@ -36,7 +36,7 @@ END(name)
 FUNCTION_DELEGATE(memcmp, memcmp_generic)
 FUNCTION_DELEGATE(memset, memset_generic)
 FUNCTION_DELEGATE(__memset_chk, __memset_chk_generic)
-FUNCTION_DELEGATE(memcpy, memcpy_generic)
+FUNCTION_DELEGATE(memcpy, memmove_generic)
 FUNCTION_DELEGATE(memmove, memmove_generic)
 FUNCTION_DELEGATE(strcpy, strcpy_generic)
 FUNCTION_DELEGATE(strncpy, strncpy_generic)