Re: Define _STRING_ARCH_unaligned unconditionally

[Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>]

On 26-03-2014 14:42, Joseph S. Myers wrote:
> On Wed, 26 Mar 2014, Adhemerval Zanella wrote:
>
>> This is a respin on my initial try to remove the undefined _STRING_ARCH_unaligned
>> from PPC64 builds, but now extended to all arch that do not define it.  This patch
>> defines _STRING_ARCH_unaligned to 0, mimicking old undefined behavior.
>>
>> --
>>
>> 	* bits/string.h (_STRING_ARCH_unaligned): Define it to 0.
> I see various files in the source tree with #ifdef / #ifndef / "defined" 
> conditionals on _STRING_ARCH_unaligned.  I don't think those are correct 
> with it defined to 0, so I think you need to change all of those are part 
> of the patch introducing the possibility that it might be defined to 0.
>
> crypt/sha256.c
> iconv/gconv_simple.c
> iconv/loop.c
> iconv/skeleton.c
> nscd/nscd_gethst_r.c
> nscd/nscd_getserv_r.c
> nscd/nscd_helper.c
> resolv/res_send.c
>
Indeed and fixed:

--

	* bits/string.h (_STRING_ARCH_unaligned): Define it to 0.
	* crypt/sha256.c (_STRING_ARCH_unaligned): Check its value instead of its
	definition.
	* iconv/gconv_simple.c (_STRING_ARCH_unaligned): Likewise.
	* iconv/loop.c (_STRING_ARCH_unaligned): Likewise.
	* iconv/skeleton.c (_STRING_ARCH_unaligned): Likewise.
	* nscd/nscd_gethst_r.c (_STRING_ARCH_unaligned): Likewise.
	* nscd/nscd_getserv_r.c (_STRING_ARCH_unaligned): Likewise.
	* nscd/nscd_helper.c (_STRING_ARCH_unaligned): Likewise.
	* resolv/res_send.c (_STRING_ARCH_unaligned): Likewise.

---

diff --git a/bits/string.h b/bits/string.h
index f8630d2..b88a6bc 100644
--- a/bits/string.h
+++ b/bits/string.h
@@ -8,5 +8,7 @@
 #ifndef _BITS_STRING_H
 #define _BITS_STRING_H	1
 
+/* Define if architecture can access unaligned multi-byte variables.  */
+#define _STRING_ARCH_unaligned   0
 
 #endif /* bits/string.h */
diff --git a/crypt/sha256.c b/crypt/sha256.c
index a5df83e..4e1b504 100644
--- a/crypt/sha256.c
+++ b/crypt/sha256.c
@@ -125,7 +125,7 @@ __sha256_finish_ctx (ctx, resbuf)
   memcpy (&ctx->buffer[bytes], fillbuf, pad);
 
   /* Put the 64-bit file length in *bits* at the end of the buffer.  */
-#ifdef _STRING_ARCH_unaligned
+#if _STRING_ARCH_unaligned
   ctx->buffer64[(bytes + pad) / 8] = SWAP64 (ctx->total64 << 3);
 #else
   ctx->buffer32[(bytes + pad + 4) / 4] = SWAP (ctx->total[TOTAL64_low] << 3);
diff --git a/iconv/gconv_simple.c b/iconv/gconv_simple.c
index e11e2ee..f357713 100644
--- a/iconv/gconv_simple.c
+++ b/iconv/gconv_simple.c
@@ -112,7 +112,7 @@ internal_ucs4_loop (struct __gconv_step *step,
   return result;
 }
 
-#ifndef _STRING_ARCH_unaligned
+#if !_STRING_ARCH_unaligned
 static inline int
 __attribute ((always_inline))
 internal_ucs4_loop_unaligned (struct __gconv_step *step,
@@ -289,7 +289,7 @@ ucs4_internal_loop (struct __gconv_step *step,
   return result;
 }
 
-#ifndef _STRING_ARCH_unaligned
+#if !_STRING_ARCH_unaligned
 static inline int
 __attribute ((always_inline))
 ucs4_internal_loop_unaligned (struct __gconv_step *step,
@@ -478,7 +478,7 @@ internal_ucs4le_loop (struct __gconv_step *step,
   return result;
 }
 
-#ifndef _STRING_ARCH_unaligned
+#if !_STRING_ARCH_unaligned
 static inline int
 __attribute ((always_inline))
 internal_ucs4le_loop_unaligned (struct __gconv_step *step,
@@ -658,7 +658,7 @@ ucs4le_internal_loop (struct __gconv_step *step,
   return result;
 }
 
-#ifndef _STRING_ARCH_unaligned
+#if !_STRING_ARCH_unaligned
 static inline int
 __attribute ((always_inline))
 ucs4le_internal_loop_unaligned (struct __gconv_step *step,
diff --git a/iconv/loop.c b/iconv/loop.c
index f836d08..f86f627 100644
--- a/iconv/loop.c
+++ b/iconv/loop.c
@@ -63,7 +63,7 @@
    representations with a fixed width of 2 or 4 bytes.  But if we cannot
    access unaligned memory we still have to read byte-wise.  */
 #undef FCTNAME2
-#if defined _STRING_ARCH_unaligned || !defined DEFINE_UNALIGNED
+#if _STRING_ARCH_unaligned || !defined DEFINE_UNALIGNED
 /* We can handle unaligned memory access.  */
 # define get16(addr) *((const uint16_t *) (addr))
 # define get32(addr) *((const uint32_t *) (addr))
@@ -342,7 +342,7 @@ FCTNAME (LOOPFCT) (struct __gconv_step *step,
 
 /* Include the file a second time to define the function to handle
    unaligned access.  */
-#if !defined DEFINE_UNALIGNED && !defined _STRING_ARCH_unaligned \
+#if !defined DEFINE_UNALIGNED && !_STRING_ARCH_unaligned \
     && MIN_NEEDED_INPUT != 1 && MAX_NEEDED_INPUT % MIN_NEEDED_INPUT == 0 \
     && MIN_NEEDED_OUTPUT != 1 && MAX_NEEDED_OUTPUT % MIN_NEEDED_OUTPUT == 0
 # undef get16
diff --git a/iconv/skeleton.c b/iconv/skeleton.c
index 14318a6..c3f161a 100644
--- a/iconv/skeleton.c
+++ b/iconv/skeleton.c
@@ -204,7 +204,7 @@
 /* Define macros which can access unaligned buffers.  These macros are
    supposed to be used only in code outside the inner loops.  For the inner
    loops we have other definitions which allow optimized access.  */
-#ifdef _STRING_ARCH_unaligned
+#if _STRING_ARCH_unaligned
 /* We can handle unaligned memory access.  */
 # define get16u(addr) *((const uint16_t *) (addr))
 # define get32u(addr) *((const uint32_t *) (addr))
@@ -523,7 +523,7 @@ FUNCTION_NAME (struct __gconv_step *step, struct __gconv_step_data *data,
 	 INTERNAL, for which the subexpression evaluates to 1, but INTERNAL
 	 buffers are always aligned correctly.  */
 #define POSSIBLY_UNALIGNED \
-  (!defined _STRING_ARCH_unaligned					      \
+  (!_STRING_ARCH_unaligned					              \
    && (((FROM_LOOP_MIN_NEEDED_FROM != 1					      \
 	 && FROM_LOOP_MAX_NEEDED_FROM % FROM_LOOP_MIN_NEEDED_FROM == 0)	      \
 	&& (FROM_LOOP_MIN_NEEDED_TO != 1				      \
diff --git a/nscd/nscd_gethst_r.c b/nscd/nscd_gethst_r.c
index fe885ee..265f4d0 100644
--- a/nscd/nscd_gethst_r.c
+++ b/nscd/nscd_gethst_r.c
@@ -191,7 +191,7 @@ nscd_gethst_r (const char *key, size_t keylen, request_type type,
 	      goto out;
 	    }
 
-#ifndef _STRING_ARCH_unaligned
+#if !_STRING_ARCH_unaligned
 	  /* The aliases_len array in the mapped database might very
 	     well be unaligned.  We will access it word-wise so on
 	     platforms which do not tolerate unaligned accesses we
diff --git a/nscd/nscd_getserv_r.c b/nscd/nscd_getserv_r.c
index 4e3f702..f079a77 100644
--- a/nscd/nscd_getserv_r.c
+++ b/nscd/nscd_getserv_r.c
@@ -141,7 +141,7 @@ nscd_getserv_r (const char *crit, size_t critlen, const char *proto,
 				> recend, 0))
 	    goto out;
 
-#ifndef _STRING_ARCH_unaligned
+#if !_STRING_ARCH_unaligned
 	  /* The aliases_len array in the mapped database might very
 	     well be unaligned.  We will access it word-wise so on
 	     platforms which do not tolerate unaligned accesses we
diff --git a/nscd/nscd_helper.c b/nscd/nscd_helper.c
index 0d61643..9fe1f46 100644
--- a/nscd/nscd_helper.c
+++ b/nscd/nscd_helper.c
@@ -490,7 +490,7 @@ __nscd_cache_search (request_type type, const char *key, size_t keylen,
       struct hashentry *here = (struct hashentry *) (mapped->data + work);
       ref_t here_key, here_packet;
 
-#ifndef _STRING_ARCH_unaligned
+#if !_STRING_ARCH_unaligned
       /* Although during garbage collection when moving struct hashentry
 	 records around we first copy from old to new location and then
 	 adjust pointer from previous hashentry to it, there is no barrier
@@ -512,7 +512,7 @@ __nscd_cache_search (request_type type, const char *key, size_t keylen,
 	  struct datahead *dh
 	    = (struct datahead *) (mapped->data + here_packet);
 
-#ifndef _STRING_ARCH_unaligned
+#if !_STRING_ARCH_unaligned
 	  if ((uintptr_t) dh & (__alignof__ (*dh) - 1))
 	    return NULL;
 #endif
@@ -536,7 +536,7 @@ __nscd_cache_search (request_type type, const char *key, size_t keylen,
 	  struct hashentry *trailelem;
 	  trailelem = (struct hashentry *) (mapped->data + trail);
 
-#ifndef _STRING_ARCH_unaligned
+#if !_STRING_ARCH_unaligned
 	  /* We have to redo the checks.  Maybe the data changed.  */
 	  if ((uintptr_t) trailelem & (__alignof__ (*trailelem) - 1))
 	    return NULL;
diff --git a/resolv/res_send.c b/resolv/res_send.c
index ce7127e..60743df 100644
--- a/resolv/res_send.c
+++ b/resolv/res_send.c
@@ -787,7 +787,7 @@ send_vc(res_state statp,
 			/* No buffer allocated for the first
 			   reply.  We can try to use the rest
 			   of the user-provided buffer.  */
-#ifdef _STRING_ARCH_unaligned
+#if _STRING_ARCH_unaligned
 			*anssizp2 = orig_anssizp - resplen;
 			*ansp2 = *ansp + resplen;
 #else
@@ -1205,7 +1205,7 @@ send_dg(res_state statp,
 				/* No buffer allocated for the first
 				   reply.  We can try to use the rest
 				   of the user-provided buffer.  */
-#ifdef _STRING_ARCH_unaligned
+#if _STRING_ARCH_unaligned
 				*anssizp2 = orig_anssizp - resplen;
 				*ansp2 = *ansp + resplen;
 #else