[Pal] Simplify memset and clean up other string ops

LICENSE.addendum.txt

@@ -19,10 +19,6 @@ cJSON - MIT
 uthash - BSD revised
 
 A number of files taken from other C libraries:
-* musl - MIT
- ** Pal/lib/string/memcmp.c
- ** Pal/lib/string/memcpy.c
- ** Pal/lib/string/strcmp.c
 * glibc - LGPL
  ** clone, sysdeps.h (and variants) used in code
  ** Pal/src/host/Linux/clone-x86_64.S
@@ -33,7 +29,6 @@ A number of files taken from other C libraries:
  ** Pal/include/sysdeps/generic/sysdep.h
  ** Pal/lib/network/hton.c
  ** Pal/lib/string/atoi.c
- ** Pal/lib/string/memset.c
  ** Pal/lib/string/strchr.c
  ** Pal/lib/string/strlen.c
  ** Pal/src/dynamic_link.h, do-rel.h , dl-machine-x86_64.h

Pal/include/lib/api.h

@@ -103,28 +103,28 @@ typedef ptrdiff_t ssize_t;
 #define __UNUSED(x) do { (void)(x); } while (0)
 #define static_strlen(str) (ARRAY_SIZE(FORCE_LITERAL_CSTR(str)) - 1)
 
-/* Libc functions */
+/* LibC functions */
 
-/* Libc String functions string.h/stdlib.h */
-size_t strnlen (const char *str, size_t maxlen);
-size_t strlen (const char *str);
+/* LibC string functions */
+size_t strnlen(const char* str, size_t maxlen);
+size_t strlen(const char* str);
 int strcmp(const char* a, const char* b);
 
-long strtol (const char *s, char **endptr, int base);
-int atoi (const char *nptr);
-long int atol (const char *nptr);
+long strtol(const char* s, char** endptr, int base);
+int atoi(const char* nptr);
+long int atol(const char* nptr);
 
 char* strchr(const char* s, int c_in);
 char* strstr(const char* haystack, const char* needle);
 
-void * memcpy (void *dstpp, const void *srcpp, size_t len);
-void * memmove (void *dstpp, const void *srcpp, size_t len);
-void * memset (void *dstpp, int c, size_t len);
-int memcmp (const void *s1, const void *s2, size_t len);
+void* memcpy(void* restrict dest, const void* restrict src, size_t count);
+void* memmove(void* dest, const void* src, size_t count);
+void* memset(void* dest, int ch, size_t count);
+int memcmp(const void* lhs, const void* rhs, size_t count);
 
 bool strendswith(const char* haystack, const char* needle);
 
-/* Libc memory allocation functions. stdlib.h. */
+/* Libc memory allocation functions */
 void *malloc(size_t size);
 void free(void *ptr);
 void *calloc(size_t nmemb, size_t size);

Pal/lib/string/memcmp.c

@@ -1,24 +1,16 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+
+#include <stdint.h>
+
 #include "api.h"
 
-/* Copyright © 2005-2014 Rich Felker, et al. */
-
-/* Permission is hereby granted, free of charge, to any person obtaining */
-/* a copy of this software and associated documentation files (the */
-/* "Software"), to deal in the Software without restriction, including */
-/* without limitation the rights to use, copy, modify, merge, publish, */
-/* distribute, sublicense, and/or sell copies of the Software, and to */
-/* permit persons to whom the Software is furnished to do so, subject to */
-/* the following conditions: */
-
-/* The above copyright notice and this permission notice shall be */
-/* included in all copies or substantial portions of the Software. */
-
-/* musl 1.1.24 */
-
-int memcmp(const void* vl, const void* vr, size_t n) {
-    const unsigned char* l=vl;
-    const unsigned char* r=vr;
-    for (; n && *l == *r; n--, l++, r++)
-        /*nop*/;
-    return n ? *l - *r : 0;
+int memcmp(const void* lhs, const void* rhs, size_t count) {
+    const unsigned char* l = lhs;
+    const unsigned char* r = rhs;
+    while (count && *l == *r) {
+        count--;
+        l++;
+        r++;
+    }
+    return count ? *l - *r : 0;
 }

Pal/lib/string/memcpy.c

@@ -1,22 +1,11 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+
+#include <stdint.h>
+
 #include "api.h"
 
-/* Copyright © 2005-2014 Rich Felker, et al. */
-
-/* Permission is hereby granted, free of charge, to any person obtaining */
-/* a copy of this software and associated documentation files (the */
-/* "Software"), to deal in the Software without restriction, including */
-/* without limitation the rights to use, copy, modify, merge, publish, */
-/* distribute, sublicense, and/or sell copies of the Software, and to */
-/* permit persons to whom the Software is furnished to do so, subject to */
-/* the following conditions: */
-
-/* The above copyright notice and this permission notice shall be */
-/* included in all copies or substantial portions of the Software. */
-
-/* heavily based on musl 1.1.15/1.1.24 */
-
-void* memcpy(void* restrict dst, const void* restrict src, size_t n) {
-    char* d = dst;
+void* memcpy(void* restrict dest, const void* restrict src, size_t count) {
+    char* d = dest;
 #if defined(__x86_64__)
     /* "Beginning with processors based on Intel microarchitecture code name Ivy Bridge, REP string
      * operation using MOVSB and STOSB can provide both flexible and high-performance REP string
@@ -26,33 +15,31 @@ void* memcpy(void* restrict dst, const void* restrict src, size_t n) {
      * memcpy() is heavily used in Linux-SGX PAL to copy data in/out of SGX enclave. Experiments
      * with Redis 5.0 show perf improvement of using "rep movsb" at 3-5% for 4KB payloads over
      * previous implementation taken from Glibc 2.23. */
-    __asm__ volatile("rep movsb" : "+D" (d) : "c"(n), "S"(src) : "cc", "memory");
+    __asm__ volatile("rep movsb" : "+&D"(d), "+&c"(count) : "S"(src) : "cc", "memory");
 #else
     const char* s = src;
-    for (; n; n--)
+    while (count--)
         *d++ = *s++;
 #endif
-    return dst;
+    return dest;
 }
 
-void* memmove(void* dst, const void* src, size_t n) {
-    char* d = dst;
+void* memmove(void* dest, const void* src, size_t count) {
+    char* d = dest;
     const char* s = src;
 
     if (d == s)
         return d;
 
-    if (s + n <= d || d + n <= s)
-        return memcpy(d, s, n);
+    if (s + count <= d || d + count <= s)
+        return memcpy(d, s, count);
 
     if (d < s) {
-        for (; n; n--)
+        while (count--)
             *d++ = *s++;
     } else {
-        while (n) {
-            n--;
-            d[n] = s[n];
-        }
+        while (count--)
+            d[count] = s[count];
     }
-    return dst;
+    return dest;
 }

Pal/lib/string/memset.c

@@ -1,85 +1,24 @@
-/* Copyright (C) 1991,1993,1995,1997,1998,2003,2004
-   Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by Torbjorn Granlund (tege@sics.se).
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/* Copyright (C) 2020 Invisible Things Lab
+ *                    Michał Kowalczyk <mkow@invisiblethingslab.com>
+ */
 
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, write to the Free
-   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
-   02111-1307 USA.  */
+#include <stdint.h>
 
 #include "api.h"
 
-#define op_t  unsigned long int
-#define OPSIZ (sizeof(op_t))
-
-typedef unsigned char byte;
-
-void* memset(void* dstpp, int c, size_t len) {
-    long int dstp = (long int)dstpp;
-
-    if (len >= 8) {
-        int xlen;
-        op_t cccc;
-
-        cccc = (unsigned char)c;
-        cccc |= cccc << 8;
-        cccc |= cccc << 16;
-        if (OPSIZ > 4) {
-            /* Do the shift in two steps to avoid warning if long has 32 bits.  */
-            cccc |= (cccc << 16) << 16;
-        }
-
-        /* There are at least some bytes to set.
-       No need to test for LEN == 0 in this alignment loop.  */
-        while (dstp % OPSIZ != 0) {
-            ((byte*)dstp)[0] = c;
-            dstp += 1;
-            len -= 1;
-        }
-
-        /* Write 8 `op_t' per iteration until less than 8 `op_t' remain.  */
-        xlen = len / (OPSIZ * 8);
-        while (xlen > 0) {
-            ((op_t*)dstp)[0] = cccc;
-            ((op_t*)dstp)[1] = cccc;
-            ((op_t*)dstp)[2] = cccc;
-            ((op_t*)dstp)[3] = cccc;
-            ((op_t*)dstp)[4] = cccc;
-            ((op_t*)dstp)[5] = cccc;
-            ((op_t*)dstp)[6] = cccc;
-            ((op_t*)dstp)[7] = cccc;
-            dstp += 8 * OPSIZ;
-            xlen -= 1;
-        }
-        len %= OPSIZ * 8;
-
-        /* Write 1 `op_t' per iteration until less than OPSIZ bytes remain.  */
-        xlen = len / OPSIZ;
-        while (xlen > 0) {
-            ((op_t*)dstp)[0] = cccc;
-            dstp += OPSIZ;
-            xlen -= 1;
-        }
-        len %= OPSIZ;
-    }
-
-    /* Write the last few bytes.  */
-    while (len > 0) {
-        ((byte*)dstp)[0] = c;
-        dstp += 1;
-        len -= 1;
-    }
-
-    return dstpp;
+void* memset(void* dest, int ch, size_t count) {
+    char* d = dest;
+#if defined(__x86_64__)
+    /* "Beginning with processors based on Intel microarchitecture code name Ivy Bridge, REP string
+     * operation using MOVSB and STOSB can provide both flexible and high-performance REP string
+     * operations for software in common situations like memory copy and set operations"
+     * Intel 64 and IA-32 Architectures Optimization Reference Manual
+     */
+    __asm__ volatile("rep stosb" : "+&D"(d), "+&c"(count) : "a"((uint8_t)ch) : "cc", "memory");
+#else
+    while (count--)
+        *d++ = ch;
+#endif
+    return dest;
 }

Pal/lib/string/strcmp.c

@@ -1,22 +1,11 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+
 #include "api.h"
 
-/* Copyright © 2005-2014 Rich Felker, et al. */
-
-/* Permission is hereby granted, free of charge, to any person obtaining */
-/* a copy of this software and associated documentation files (the */
-/* "Software"), to deal in the Software without restriction, including */
-/* without limitation the rights to use, copy, modify, merge, publish, */
-/* distribute, sublicense, and/or sell copies of the Software, and to */
-/* permit persons to whom the Software is furnished to do so, subject to */
-/* the following conditions: */
-
-/* The above copyright notice and this permission notice shall be */
-/* included in all copies or substantial portions of the Software. */
-
-/* musl 1.1.24 */
-
-int strcmp(const char* l, const char* r) {
-    for (; *l == *r && *l; l++, r++)
-        ;
-    return *(unsigned char*)l - *(unsigned char*)r;
+int strcmp(const char* lhs, const char* rhs) {
+    while (*lhs == *rhs && *lhs) {
+        lhs++;
+        rhs++;
+    }
+    return *(unsigned char*)lhs - *(unsigned char*)rhs;
 }