PERFORCE change 104167 for review

[John Birrell]

http://perforce.freebsd.org/chv.cgi?CH=104167

Change 104167 by jb at jb_freebsd2 on 2006/08/16 01:30:34

	Revert back to using my memcpy version of this file which works on
	sun4v. Revision 5 certainly stopped the compiler warnings about
	alignment, but the compiler was doing the right thing. Adding another
	cast to avoid the warning just masked the problem.

Affected files ...

.. //depot/projects/dtrace/src/lib/libelf/libelf_convert.m4#6 edit

Differences ...

==== //depot/projects/dtrace/src/lib/libelf/libelf_convert.m4#6 (text+ko) ====

@@ -1,3 +1,4 @@
+//depot/projects/dtrace/src/lib/libelf/libelf_convert.m4#4 - edit change 103978 (text+ko)
 /*-
  * Copyright (c) 2006 Joseph Koshy
  * All rights reserved.
@@ -152,7 +153,7 @@
 		(X)		= _t;					\
 	} while (0)
 #define	READ_WORD(P,X)	do {						\
-		uint16_t _t;						\
+		uint32_t _t;						\
 		unsigned char *const _q = (unsigned char *) &_t;	\
 		const unsigned char *const _p =				\
 			(const unsigned char *) (P);			\
@@ -167,7 +168,7 @@
 #define	READ_OFF32(P,X)		READ_WORD(P,X)
 #define	READ_SWORD(P,X)		READ_WORD(P,X)
 #define	READ_WORD64(P,X)	do {					\
-		uint16_t _t;						\
+		uint64_t _t;						\
 		unsigned char *const _q = (unsigned char *) &_t;	\
 		const unsigned char *const _p =				\
 			(const unsigned char *) (P);			\
@@ -188,6 +189,7 @@
 #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)
@@ -201,16 +203,9 @@
  * 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 additional complication is that `ar' only pads data
+ * byte order.  An additinal 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')
@@ -257,19 +252,20 @@
 static void
 libelf_cvt_$1$3_tof(char *dst, char *src, int count, int byteswap)
 {
-	Elf64_$2 t, *s = (Elf64_$2 *) (uintptr_t) src;
+	Elf64_$2 t;
 	int c;
 
 	if (dst == src && !byteswap)
 		return;
 
 	if (!byteswap) {
-		(void) memcpy(dst, src, count * sizeof(*s));
+		(void) memcpy(dst, src, count * sizeof(t));
 		return;
 	}
 
 	for (c = 0; c < count; c++) {
-		t = *s++;
+		memcpy(&t, src, sizeof(t));
+		src += sizeof(t);
 		SWAP_$1$3(t);
 		WRITE_$1$3(dst,t);
 	}
@@ -280,21 +276,22 @@
 static void
 libelf_cvt_$1$3_tom(char *dst, char *src, int count, int byteswap)
 {
-	Elf64_$2 t, *d = (Elf64_$2 *) (uintptr_t) dst;
+	Elf64_$2 t;
 	int c;
 
 	if (dst == src && !byteswap)
 		return;
 
 	if (!byteswap) {
-		(void) memcpy(dst, src, count * sizeof(*d));
+		(void) memcpy(dst, src, count * sizeof(t));
 		return;
 	}
 
 	for (c = 0; c < count; c++) {
 		READ_$1$3(src,t);
 		SWAP_$1$3(t);
-		*d++ = t;
+		memcpy(dst, &t, sizeof(t));
+		dst += sizeof(t);
 	}
 }
 ')
@@ -370,12 +367,12 @@
 static void
 libelf_cvt$3_$1_tof(char *dst, char *src, int count, int byteswap)
 {
-	Elf$3_$2	t, *s;
+	Elf$3_$2	t;
 	int c;
 
-	s = (Elf$3_$2 *) (uintptr_t) src;
 	for (c = 0; c < count; c++) {
-		t = *s++;
+		memcpy(&t, src, sizeof(t));
+		src += sizeof(t);
 		if (byteswap) {
 			SWAP_STRUCT($2,$3)
 		}
@@ -389,21 +386,22 @@
 static void
 libelf_cvt$3_$1_tom(char *dst, char *src, int count, int byteswap)
 {
-	Elf$3_$2	 t, *d;
-	unsigned char	*s,*s0;
+	Elf$3_$2	t;
+	unsigned char	*s;
+	int		i;
 	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;
 
-	while (count--) {
-		s = s0;
+	for (i = 0; i < count; i++) {
+		s = (unsigned char *) src;
 		READ_STRUCT($2,$3)
 		if (byteswap) {
 			SWAP_STRUCT($2,$3)
 		}
-		*d-- = t; s0 -= fsz;
+		memcpy(dst, &t, sizeof(t));
+		dst += sizeof(t);
+		src += fsz;
 	}
 }
 ')')