PERFORCE change 104119 for review

[John Birrell]

http://perforce.freebsd.org/chv.cgi?CH=104119

Change 104119 by jb at jb_freebsd2 on 2006/08/15 20:38:00

	IFlibbsdelf

Affected files ...

.. //depot/projects/dtrace/src/lib/libelf/Makefile#6 integrate
.. //depot/projects/dtrace/src/lib/libelf/elf_getarhdr.3#1 branch
.. //depot/projects/dtrace/src/lib/libelf/elf_getarsym.3#1 branch
.. //depot/projects/dtrace/src/lib/libelf/elf_next.c#5 integrate
.. //depot/projects/dtrace/src/lib/libelf/libelf_convert.m4#5 integrate

Differences ...

==== //depot/projects/dtrace/src/lib/libelf/Makefile#6 (text+ko) ====

@@ -59,6 +59,8 @@
 	elf_end.3 elf_errmsg.3					\
 	elf_fill.3						\
 	elf_flagdata.3						\
+	elf_getarhdr.3						\
+	elf_getarsym.3						\
 	elf_getbase.3						\
 	elf_getident.3						\
 	elf_hash.3						\
@@ -104,8 +106,6 @@
 	elf_flagdata.3 elf_flagphdr.3 \
 	elf_flagdata.3 elf_flagscn.3 \
 	elf_flagdata.3 elf_flagshdr.3 \
-	elf.3 elf_getarhdr.3 \
-	elf.3 elf_getarsym.3 \
 	elf.3 elf_getdata.3 \
 	elf.3 elf_getscn.3 \
 	elf.3 elf_ndxscn.3 \

==== //depot/projects/dtrace/src/lib/libelf/elf_next.c#5 (text+ko) ====


==== //depot/projects/dtrace/src/lib/libelf/libelf_convert.m4#5 (text+ko) ====

@@ -152,7 +152,7 @@
 		(X)		= _t;					\
 	} while (0)
 #define	READ_WORD(P,X)	do {						\
-		uint32_t _t;						\
+		uint16_t _t;						\
 		unsigned char *const _q = (unsigned char *) &_t;	\
 		const unsigned char *const _p =				\
 			(const unsigned char *) (P);			\
@@ -167,7 +167,7 @@
 #define	READ_OFF32(P,X)		READ_WORD(P,X)
 #define	READ_SWORD(P,X)		READ_WORD(P,X)
 #define	READ_WORD64(P,X)	do {					\
-		uint64_t _t;						\
+		uint16_t _t;						\
 		unsigned char *const _q = (unsigned char *) &_t;	\
 		const unsigned char *const _p =				\
 			(const unsigned char *) (P);			\
@@ -188,7 +188,6 @@
 #define	READ_XWORD(P,X)		READ_WORD64(P,X)
 #define	READ_IDENT(P,X)		do {					\
 		(void) memcpy((X), (P), sizeof((X)));			\
-		(P)             = (P) + sizeof((X));			\
 	} while (0)
 
 divert(-1)
@@ -202,9 +201,16 @@
  * casting to work as expected.  On the other hand the `file'
  * representation of an ELF data structure could be packed tighter
  * than its `in-memory' representation, and could be of a differing
- * byte order.  An additinal complication is that `ar' only pads data
+ * byte order.  An additional complication is that `ar' only pads data
  * to even addresses and so ELF archive member data being read from
  * inside an `ar' archive could end up at misaligned memory addresses.
+ *
+ * Consequently, casting the `char *' pointers that point to memory
+ * representations (i.e., source pointers for the *_tof() functions
+ * and the destination pointers for the *_tom() functions), is safe,
+ * as these pointers should be correctly aligned for the memory type
+ * already.  However, pointers to file representations have to be
+ * treated as being potentially unaligned and no casting can be done.
  */
 
 include(SRCDIR`/elf_types.m4')
@@ -251,20 +257,19 @@
 static void
 libelf_cvt_$1$3_tof(char *dst, char *src, int count, int byteswap)
 {
-	Elf64_$2 t;
+	Elf64_$2 t, *s = (Elf64_$2 *) (uintptr_t) src;
 	int c;
 
 	if (dst == src && !byteswap)
 		return;
 
 	if (!byteswap) {
-		(void) memcpy(dst, src, count * sizeof(t));
+		(void) memcpy(dst, src, count * sizeof(*s));
 		return;
 	}
 
 	for (c = 0; c < count; c++) {
-		memcpy(&t, src, sizeof(t));
-		src += sizeof(t);
+		t = *s++;
 		SWAP_$1$3(t);
 		WRITE_$1$3(dst,t);
 	}
@@ -275,22 +280,21 @@
 static void
 libelf_cvt_$1$3_tom(char *dst, char *src, int count, int byteswap)
 {
-	Elf64_$2 t;
+	Elf64_$2 t, *d = (Elf64_$2 *) (uintptr_t) dst;
 	int c;
 
 	if (dst == src && !byteswap)
 		return;
 
 	if (!byteswap) {
-		(void) memcpy(dst, src, count * sizeof(t));
+		(void) memcpy(dst, src, count * sizeof(*d));
 		return;
 	}
 
 	for (c = 0; c < count; c++) {
 		READ_$1$3(src,t);
 		SWAP_$1$3(t);
-		memcpy(dst, &t, sizeof(t));
-		dst += sizeof(t);
+		*d++ = t;
 	}
 }
 ')
@@ -366,12 +370,12 @@
 static void
 libelf_cvt$3_$1_tof(char *dst, char *src, int count, int byteswap)
 {
-	Elf$3_$2	t;
+	Elf$3_$2	t, *s;
 	int c;
 
+	s = (Elf$3_$2 *) (uintptr_t) src;
 	for (c = 0; c < count; c++) {
-		memcpy(&t, src, sizeof(t));
-		src += sizeof(t);
+		t = *s++;
 		if (byteswap) {
 			SWAP_STRUCT($2,$3)
 		}
@@ -385,22 +389,21 @@
 static void
 libelf_cvt$3_$1_tom(char *dst, char *src, int count, int byteswap)
 {
-	Elf$3_$2	t;
-	unsigned char	*s;
-	int		i;
+	Elf$3_$2	 t, *d;
+	unsigned char	*s,*s0;
 	size_t		fsz;
 
 	fsz = elf$3_fsize(ELF_T_$1, 1, EV_CURRENT);
+	d   = ((Elf$3_$2 *) (uintptr_t) dst) + (count - 1);
+	s0  = (unsigned char *) src + (count - 1) * fsz;
 
-	for (i = 0; i < count; i++) {
-		s = (unsigned char *) src;
+	while (count--) {
+		s = s0;
 		READ_STRUCT($2,$3)
 		if (byteswap) {
 			SWAP_STRUCT($2,$3)
 		}
-		memcpy(dst, &t, sizeof(t));
-		dst += sizeof(t);
-		src += fsz;
+		*d-- = t; s0 -= fsz;
 	}
 }
 ')')