since gcc -Os hates us and does not inline string ops,

implement inline versions of some of them.
Enable only those which result roughly in the same
code size as using out-or-line versions.

None of this affects users, installed headers won't have
any trace of it.

2 files changed, 332 insertions, 11 deletions

diff --git a/include/libc-string_i386.h b/include/libc-string_i386.h
new file mode 100644
index 000000000..3ed9c8783
--- /dev/null
+++ b/include/libc-string_i386.h
@@ -0,0 +1,314 @@
+/*
+ * Copyright (C) 2008 Denys Vlasenko <vda.linux@googlemail.com>
+ *
+ * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball
+ */
+
+#if !defined _STRING_H
+#error "Never use <libc-string_i386.h> directly; include <string.h> instead"
+#endif
+
+#ifndef _LIBC_STRING_i386_H
+#define _LIBC_STRING_i386_H 1
+
+static __always_inline
+void *inlined_memset_const_c_count4(void *s, unsigned eax, unsigned count)
+{
+	int ecx, edi;
+
+	if (count == 0)
+		return s;
+
+	/* Very small (2 stores or less) are best done with direct
+	 * mov <const>,<mem> instructions (they do not clobber registers) */
+	if (count == 1) {
+		*(char *)(s + 0) = eax;
+		return s;
+	}
+
+	eax *= 0x01010101; /* done at compile time */
+
+	if (count == 2) {
+		*(short *)(s + 0) = eax;
+		return s;
+	}
+	if (count == 3) {
+		*(short *)(s + 0) = eax;
+		*(char *) (s + 2) = eax;
+		return s;
+	}
+	if (count == 1*4 + 0) {
+		*(int *)(s + 0) = eax;
+		return s;
+	}
+	if (count == 1*4 + 1) {
+		*(int *) (s + 0) = eax;
+		*(char *)(s + 4) = eax;
+		return s;
+	}
+	if (count == 1*4 + 2) {
+		*(int *)  (s + 0) = eax;
+		*(short *)(s + 4) = eax;
+		return s;
+	}
+
+	/* Small string stores: don't clobber ecx
+	 * (clobbers only eax and edi) */
+#define small_store(arg) { \
+	__asm__ __volatile__( \
+		arg \
+		: "=&D" (edi) \
+		: "a" (eax), "0" (s) \
+		: "memory" \
+	); \
+	return s; \
+}
+	if (count == 1*4 + 3) small_store("stosl; stosw; stosb");
+	if (count == 2*4 + 0) {
+		((int *)s)[0] = eax;
+		((int *)s)[1] = eax;
+		return s;
+	}
+	if (count == 2*4 + 1) small_store("stosl; stosl; stosb");
+	if (count == 2*4 + 2) small_store("stosl; stosl; stosw");
+	if (count == 2*4 + 3) small_store("stosl; stosl; stosw; stosb");
+	if (count == 3*4 + 0) small_store("stosl; stosl; stosl");
+	if (count == 3*4 + 1) small_store("stosl; stosl; stosl; stosb");
+	if (count == 3*4 + 2) small_store("stosl; stosl; stosl; stosw");
+	if (count == 3*4 + 3) small_store("stosl; stosl; stosl; stosw; stosb");
+	if (count == 4*4 + 0) small_store("stosl; stosl; stosl; stosl");
+	if (count == 4*4 + 1) small_store("stosl; stosl; stosl; stosl; stosb");
+	/* going over 7 bytes is suboptimal */
+	/* stosw is 2-byte insn, so this one takes 6 bytes: */
+	if (count == 4*4 + 2) small_store("stosl; stosl; stosl; stosl; stosw");
+	/* 7 bytes */
+	if (count == 4*4 + 3) small_store("stosl; stosl; stosl; stosl; stosw; stosb");
+	/* 5 bytes */
+	if (count == 5*4 + 0) small_store("stosl; stosl; stosl; stosl; stosl");
+	/* 6 bytes */
+	if (count == 5*4 + 1) small_store("stosl; stosl; stosl; stosl; stosl; stosb");
+	/* 7 bytes */
+	if (count == 5*4 + 2) small_store("stosl; stosl; stosl; stosl; stosl; stosw");
+	/* 8 bytes, but oh well... */
+	if (count == 5*4 + 3) small_store("stosl; stosl; stosl; stosl; stosl; stosw; stosb");
+	/* 6 bytes */
+	if (count == 6*4 + 0) small_store("stosl; stosl; stosl; stosl; stosl; stosl");
+	/* the rest would be 7+ bytes and is handled below instead */
+#undef small_store
+
+	/* Not small, but multiple-of-4 store.
+	 * "mov <const>,%ecx; rep; stosl" sequence is 7 bytes */
+	__asm__ __volatile__(
+		"	rep; stosl\n"
+		: "=&c" (ecx), "=&D" (edi)
+		: "a" (eax), "0" (count / 4), "1" (s)
+		: "memory"
+	);
+	return s;
+}
+#if 1 /* -51 bytes on shared i386 build with gcc 4.3.0 */
+#define memset(s, c, count) ( \
+	( !(__builtin_constant_p(c) && __builtin_constant_p(count)) \
+	  || ((count) > (6*4 + 0) && ((count) % 4) != 0) \
+	) \
+	? memset((s), (c), (count)) \
+	: inlined_memset_const_c_count4((s), (c), (count)) \
+	)
+#endif
+
+
+static __always_inline
+void *inlined_mempcpy_const_count4(void *d, const void *s, unsigned count)
+{
+	int ecx;
+	char *esi, *edi;
+
+	if (count == 0)
+		return d;
+
+	if (count == 1) {
+		*(char *)d = *(char *)s;
+		return d + 1;
+	}
+	if (count == 2) {
+		*(short *)d = *(short *)s;
+		return d + 2;
+	}
+	/* Small string moves: don't clobber ecx
+	 * (clobbers only esi and edi) */
+#define small_move(arg) { \
+	__asm__ __volatile__( \
+		arg \
+		: "=&S" (esi), "=&D" (edi) \
+		: "0" (s), "1" (d) \
+		: "memory" \
+	); \
+	return edi; \
+}
+	if (count == 3) small_move("movsw; movsb");
+	if (count == 1*4 + 0) {
+		*(int *)d = *(int *)s;
+		return d + 4;
+	}
+	if (count == 1*4 + 1) small_move("movsl; movsb");
+	if (count == 1*4 + 2) small_move("movsl; movsw");
+	if (count == 1*4 + 3) small_move("movsl; movsw; movsb");
+	if (count == 2*4 + 0) small_move("movsl; movsl");
+	if (count == 2*4 + 1) small_move("movsl; movsl; movsb");
+	if (count == 2*4 + 2) small_move("movsl; movsl; movsw");
+	if (count == 2*4 + 3) small_move("movsl; movsl; movsw; movsb");
+	if (count == 3*4 + 0) small_move("movsl; movsl; movsl");
+	if (count == 3*4 + 1) small_move("movsl; movsl; movsl; movsb");
+	if (count == 3*4 + 2) small_move("movsl; movsl; movsl; movsw");
+	if (count == 3*4 + 3) small_move("movsl; movsl; movsl; movsw; movsb");
+	if (count == 4*4 + 0) small_move("movsl; movsl; movsl; movsl");
+	if (count == 4*4 + 1) small_move("movsl; movsl; movsl; movsl; movsb");
+	/* going over 7 bytes is suboptimal */
+	/* movsw is 2-byte insn, so this one takes 6 bytes: */
+	if (count == 4*4 + 2) small_move("movsl; movsl; movsl; movsl; movsw");
+	/* 7 bytes */
+	if (count == 4*4 + 3) small_move("movsl; movsl; movsl; movsl; movsw; movsb");
+	/* 5 bytes */
+	if (count == 5*4 + 0) small_move("movsl; movsl; movsl; movsl; movsl");
+	/* 6 bytes */
+	if (count == 5*4 + 1) small_move("movsl; movsl; movsl; movsl; movsl; movsb");
+	/* 7 bytes */
+	if (count == 5*4 + 2) small_move("movsl; movsl; movsl; movsl; movsl; movsw");
+	/* 8 bytes, but oh well... */
+	if (count == 5*4 + 3) small_move("movsl; movsl; movsl; movsl; movsl; movsw; movsb");
+	/* 6 bytes */
+	if (count == 6*4 + 0) small_move("movsl; movsl; movsl; movsl; movsl; movsl");
+	/* the rest would be 7+ bytes and is handled below instead */
+#undef small_move
+
+	/* Not small, but multiple-of-4 move.
+	 * "mov <const>,%ecx; rep; movsl" sequence is 7 bytes */
+	__asm__ __volatile__(
+		"	rep; movsl\n"
+		: "=&c" (ecx), "=&S" (esi), "=&D" (edi)
+		: "0" (count / 4), "1" (s), "2" (d)
+		: "memory"
+	);
+	return edi;
+}
+static __always_inline
+void *inlined_memcpy_const_count4(void *d, const void *s, unsigned count)
+{
+	inlined_mempcpy_const_count4(d, s, count);
+	return d;
+}
+#if 1 /* +34 bytes on shared i386 build with gcc 4.3.0 */
+#define mempcpy(d, s, count) ( \
+	( !(__builtin_constant_p(count)) \
+	  || ((count) > (6*4 + 0) && ((count) % 4) != 0) \
+	) \
+	? mempcpy((d), (s), (count)) \
+	: inlined_mempcpy_const_count4((d), (s), (count)) \
+	)
+#define memcpy(d, s, count) ( \
+	( !(__builtin_constant_p(count)) \
+	  || ((count) > (6*4 + 0) && ((count) % 4) != 0) \
+	) \
+	? memcpy((d), (s), (count)) \
+	: inlined_memcpy_const_count4((d), (s), (count)) \
+	)
+#endif
+
+
+static __always_inline
+size_t inlined_strlen(const char *s)
+{
+	int edi;
+	int ecx;
+	__asm__ __volatile__(
+		"	repne; scasb\n"
+	/*	"	notl	%0\n" */
+	/*	"	decl	%0\n" */
+		: "=c" (ecx), "=&D" (edi)
+		: "1" (s), "a" (0), "0" (0xffffffffu)
+		/* : no clobbers */
+	);
+	return -ecx - 1;
+}
+#if 0 /* +1108 bytes on shared i386 build with gcc 4.3.0 */
+#define strlen(s) inlined_strlen(s)
+#endif
+
+
+static __always_inline
+char *inlined_stpcpy(char *dest, const char *src)
+{
+	char *esi, *edi;
+	int eax;
+	__asm__ __volatile__(
+		"1:	lodsb\n"
+		"	stosb\n"
+		"	testb	%%al, %%al\n"
+		"	jnz	1b\n"
+		: "=&S" (esi), "=&D" (edi), "=&a" (eax)
+		: "0" (src), "1" (dest)
+		: "memory"
+	);
+	return edi - 1;
+}
+static __always_inline
+char *inlined_strcpy(char *dest, const char *src)
+{
+	inlined_stpcpy(dest, src);
+	return dest;
+}
+#if 0 /* +562 bytes on shared i386 build with gcc 4.3.0 */
+#define stpcpy(dest, src) inlined_stpcpy(dest, src)
+#define strcpy(dest, src) inlined_strcpy(dest, src)
+#endif
+
+
+static __always_inline
+void *inlined_memchr(const void *s, int c, size_t count)
+{
+	void *edi;
+	int ecx;
+	/* Unfortunately, c gets loaded to %eax (wide insn), not %al */
+	__asm__ __volatile__(
+		"	jecxz	1f\n"
+		"	repne; scasb\n"
+		"	leal	-1(%%edi), %%edi\n"
+		"	je	2f\n"
+		"1:\n"
+		"	xorl	%%edi, %%edi\n"
+		"2:\n"
+		: "=&D" (edi), "=&c" (ecx)
+		: "a" (c), "0" (s), "1" (count)
+		/* : no clobbers */
+	);
+	return edi;
+}
+static __always_inline
+void *inlined_memchr_const_c(const void *s, int c, size_t count)
+{
+	void *edi;
+	int ecx, eax;
+	__asm__ __volatile__(
+		"	jecxz	1f\n"
+		"	movb	%4, %%al\n" /* const c to %%al */
+		"	repne; scasb\n"
+		"	leal	-1(%%edi), %%edi\n"
+		"	je	2f\n"
+		"1:\n"
+		"	xorl	%%edi, %%edi\n"
+		"2:\n"
+		: "=&D" (edi), "=&c" (ecx), "=&a" (eax)
+		: "0" (s), "i" (c), "1" (count)
+		/* : no clobbers */
+	);
+	return edi;
+}
+#if 1 /* +2 bytes on shared i386 build with gcc 4.3.0 */
+#define memchr(s, c, count) ( \
+	__builtin_constant_p(c) \
+	? inlined_memchr_const_c(s, (c) & 0xff, count) \
+	: inlined_memchr(s, c, count) \
+	)
+#endif
+
+#endif /* _LIBC_STRING_i386_H  */
diff --git a/include/string.h b/include/string.h
index e889dc11a..ab1076565 100644
--- a/include/string.h
+++ b/include/string.h
@@ -378,7 +378,7 @@ libc_hidden_proto(ffs)
 
 /* The following two functions are non-standard but necessary for non-32 bit
    platforms.  */
-#if 0 /*def	__USE_GNU*/
+# if 0 /*#ifdef __USE_GNU*/
 extern int ffsl (long int __l) __THROW __attribute__ ((__const__));
 #  ifdef __GNUC__
 __extension__ extern int ffsll (long long int __ll)
@@ -422,44 +422,44 @@ libc_hidden_proto(strsep)
 
 #ifdef	__USE_GNU
 /* Compare S1 and S2 as strings holding name & indices/version numbers.  */
-#if 0
+# if 0
 extern int strverscmp (__const char *__s1, __const char *__s2)
      __THROW __attribute_pure__ __nonnull ((1, 2));
 libc_hidden_proto(strverscmp)
-#endif
+# endif
 
 /* Return a string describing the meaning of the signal number in SIG.  */
 extern char *strsignal (int __sig) __THROW;
 libc_hidden_proto(strsignal)
 
 /* Copy SRC to DEST, returning the address of the terminating '\0' in DEST.  */
-#if 0 /* uClibc: disabled */
+# if 0 /* uClibc: disabled */
 extern char *__stpcpy (char *__restrict __dest, __const char *__restrict __src)
      __THROW __nonnull ((1, 2));
-#endif
+# endif
 extern char *stpcpy (char *__restrict __dest, __const char *__restrict __src)
      __THROW __nonnull ((1, 2));
 libc_hidden_proto(stpcpy)
 
 /* Copy no more than N characters of SRC to DEST, returning the address of
    the last character written into DEST.  */
-#if 0 /* uClibc: disabled */
+# if 0 /* uClibc: disabled */
 extern char *__stpncpy (char *__restrict __dest,
 			__const char *__restrict __src, size_t __n)
      __THROW __nonnull ((1, 2));
-#endif
+# endif
 extern char *stpncpy (char *__restrict __dest,
 		      __const char *__restrict __src, size_t __n)
      __THROW __nonnull ((1, 2));
 libc_hidden_proto(stpncpy)
 
-#if 0							/* uClibc does not support strfry or memfrob. */
+# if 0			/* uClibc does not support strfry or memfrob. */
 /* Sautee STRING briskly.  */
 extern char *strfry (char *__string) __THROW __nonnull ((1));
 
 /* Frobnicate N bytes of S.  */
 extern void *memfrob (void *__s, size_t __n) __THROW __nonnull ((1));
-#endif
+# endif
 
 # ifndef basename
 /* Return the file name within directory of FILENAME.  We don't
@@ -469,7 +469,7 @@ extern void *memfrob (void *__s, size_t __n) __THROW __nonnull ((1));
 extern char *basename (__const char *__filename) __THROW __nonnull ((1));
 libc_hidden_proto(basename)
 # endif
-#endif
+#endif /* __USE_GNU */
 
 
 #ifdef	__USE_BSD
@@ -484,4 +484,11 @@ libc_hidden_proto(strlcpy)
 
 __END_DECLS
 
-#endif /* string.h  */
+
+#ifdef UCLIBC_INTERNAL
+# if defined __i386__
+#  include <libc-string_i386.h>
+# endif
+#endif
+
+#endif /* string.h */