From 71a1a0f485fb64e5996a6edfe1534e66a7e74add Mon Sep 17 00:00:00 2001
From: drh <drh@noemail.net>
Date: Sat, 11 Sep 2010 16:15:55 +0000
Subject: [PATCH] Additional evidence marks on the malloc() implementation. 
 Update the documentation to explain that mallocs are not necessarily 8-byte
 aligned if the SQLITE_4_BYTE_ALIGNED_MALLOC compile-time option is used.

FossilOrigin-Name: 42b4bf9e72501cf228b4086437c7660443933f74
---
 manifest        | 14 +++++++-------
 manifest.uuid   |  2 +-
 src/malloc.c    | 10 ++++++----
 src/sqlite.h.in |  4 +++-
 4 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/manifest b/manifest
index f8db8e97bc..81616d2b87 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Add\sassert()\sstatements\sto\sdemonstrate\sthat\smemory\sallocations\sare\salways\naligned\sto\san\s8-byte\sboundary\s(unless\sSQLITE_4_BYTE_ALIGNED_MALLOC\sis\sdefined).
-D 2010-09-11T15:54:53
+C Additional\sevidence\smarks\son\sthe\smalloc()\simplementation.\s\sUpdate\sthe\s\ndocumentation\sto\sexplain\sthat\smallocs\sare\snot\snecessarily\s8-byte\saligned\nif\sthe\sSQLITE_4_BYTE_ALIGNED_MALLOC\scompile-time\soption\sis\sused.
+D 2010-09-11T16:15:56
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in c599a15d268b1db2aeadea19df2adc3bf2eb6bee
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -140,7 +140,7 @@ F src/legacy.c a199d7683d60cef73089e892409113e69c23a99f
 F src/lempar.c 7f026423f4d71d989e719a743f98a1cbd4e6d99e
 F src/loadext.c 6d422ea91cf3d2d00408c5a8f2391cd458da85f8
 F src/main.c da74b2269470d97a702d2956eeeb691a5e3a68c3
-F src/malloc.c ab48f49442aa78c8c7019845c634ac05b07e59dc
+F src/malloc.c 44a50eb10bb755a7b27799b41b874e53bd6e24e3
 F src/mem0.c 6a55ebe57c46ca1a7d98da93aaa07f99f1059645
 F src/mem1.c 00bd8265c81abb665c48fea1e0c234eb3b922206
 F src/mem2.c e307323e86b5da1853d7111b68fd6b84ad6f09cf
@@ -174,7 +174,7 @@ F src/resolve.c 1c0f32b64f8e3f555fe1f732f9d6f501a7f05706
 F src/rowset.c 69afa95a97c524ba6faf3805e717b5b7ae85a697
 F src/select.c b0b124781474e4e0c8f64022875e5e2009e13443
 F src/shell.c 8517fc1f9c59ae4007e6cc8b9af91ab231ea2056
-F src/sqlite.h.in 8cae23448cb0ebe0990d305c32435c2dfb21f937
+F src/sqlite.h.in b70c0ad68365a229800af55abe9210f1964c1d31
 F src/sqlite3ext.h 69dfb8116af51b84a029cddb3b35062354270c89
 F src/sqliteInt.h 81343db96497aebf81dff9c695dfd29699b377b3
 F src/sqliteLimit.h a17dcd3fb775d63b64a43a55c54cb282f9726f44
@@ -857,7 +857,7 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
-P 5b63e981f1bef26eae0da3144a08bdc54dc36709
-R 5f696ac739736af24121b122c94485c1
+P 305cc4e6c1164b1ede0c3177e3c0f9b8644df0f6
+R d4739e5fcf915e019da850204032c340
 U drh
-Z 6c746302b511dbe67ce0549fd9634e5e
+Z 342cca73834b234d21ed5424a5f029e5
diff --git a/manifest.uuid b/manifest.uuid
index d67b6d88bb..cf0d4b2849 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-305cc4e6c1164b1ede0c3177e3c0f9b8644df0f6
\ No newline at end of file
+42b4bf9e72501cf228b4086437c7660443933f74
\ No newline at end of file
diff --git a/src/malloc.c b/src/malloc.c
index 948eb91d13..d7a103b111 100644
--- a/src/malloc.c
+++ b/src/malloc.c
@@ -293,7 +293,9 @@ static int mallocWithAlarm(int n, void **pp){
 */
 void *sqlite3Malloc(int n){
   void *p;
-  if( n<=0 || n>=0x7fffff00 ){
+  if( n<=0               /* IMP: R-65312-04917 */ 
+   || n>=0x7fffff00
+  ){
     /* A memory allocation of a number of bytes which is near the maximum
     ** signed integer value might cause an integer overflow inside of the
     ** xMalloc().  Hence we limit the maximum size to 0x7fffff00, giving
@@ -459,7 +461,7 @@ int sqlite3DbMallocSize(sqlite3 *db, void *p){
 ** Free memory previously obtained from sqlite3Malloc().
 */
 void sqlite3_free(void *p){
-  if( p==0 ) return;
+  if( p==0 ) return;  /* IMP: R-49053-54554 */
   assert( sqlite3MemdebugNoType(p, MEMTYPE_DB) );
   assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
   if( sqlite3GlobalConfig.bMemstat ){
@@ -506,10 +508,10 @@ void *sqlite3Realloc(void *pOld, int nBytes){
   int nOld, nNew;
   void *pNew;
   if( pOld==0 ){
-    return sqlite3Malloc(nBytes);
+    return sqlite3Malloc(nBytes); /* IMP: R-28354-25769 */
   }
   if( nBytes<=0 ){
-    sqlite3_free(pOld);
+    sqlite3_free(pOld); /* IMP: R-31593-10574 */
     return 0;
   }
   if( nBytes>=0x7fffff00 ){
diff --git a/src/sqlite.h.in b/src/sqlite.h.in
index 613ee6e148..a7bc0d0508 100644
--- a/src/sqlite.h.in
+++ b/src/sqlite.h.in
@@ -1947,7 +1947,9 @@ char *sqlite3_snprintf(int,char*,const char*, ...);
 ** is not freed.
 **
 ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc()
-** is always aligned to at least an 8 byte boundary.
+** is always aligned to at least an 8 byte boundary, or to a
+** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
+** option is used.
 **
 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in