Merge r1815:1817 from branches/zip: Improve Valgrind instrumentation.

UNIV_MEM_ASSERT_RW(): New macro, to check that the contents of a memory
area is defined.

UNIV_MEM_ASSERT_W(): New macro, to check that a memory area is writable.

UNIV_MEM_ASSERT_AND_FREE(): New macro, to check that the memory is
writable before declaring it free (unwritable).  This replaces UNIV_MEM_FREE()
in many places.

mem_init_buf(): Check that the memory is writable, and declare it undefined.

mem_erase_buf(): Check that the memory is writable, and declare it freed.

buf/buf0lru.c

@@ -881,7 +881,7 @@ buf_LRU_block_free_non_file_page(
 	UT_LIST_ADD_FIRST(free, buf_pool->free, block);
 	block->in_free_list = TRUE;
 
-	UNIV_MEM_FREE(block->frame, UNIV_PAGE_SIZE);
+	UNIV_MEM_ASSERT_AND_FREE(block->frame, UNIV_PAGE_SIZE);
 
 	if (srv_use_awe && block->frame) {
 		/* Add to the list of mapped pages */

include/mem0mem.ic

@@ -271,18 +271,14 @@ mem_heap_free_heap_top(
 	ut_ad(mem_block_get_start(block) <= mem_block_get_free(block));
 
 	/* In the debug version erase block from top up */
-	{
-		ulint	len = (byte*)block + block->len - old_top;
-		mem_erase_buf(old_top, len);
-		UNIV_MEM_FREE(old_top, len);
-	}
+	mem_erase_buf(old_top, (byte*)block + block->len - old_top);
 
 	/* Update allocated memory count */
 	mutex_enter(&mem_hash_mutex);
 	mem_current_allocated_memory -= (total_size - size);
 	mutex_exit(&mem_hash_mutex);
 #else /* UNIV_MEM_DEBUG */
-	UNIV_MEM_FREE(old_top, (byte*)block + block->len - old_top);
+	UNIV_MEM_ASSERT_AND_FREE(old_top, (byte*)block + block->len - old_top);
 #endif /* UNIV_MEM_DEBUG */
 
 	/* If free == start, we may free the block if it is not the first
@@ -363,6 +359,7 @@ mem_heap_free_top(
 	/* Subtract the free field of block */
 	mem_block_set_free(block, mem_block_get_free(block)
 			   - MEM_SPACE_NEEDED(n));
+	UNIV_MEM_ASSERT_W((byte*) block + mem_block_get_free(block), n);
 #ifdef UNIV_MEM_DEBUG
 
 	ut_ad(mem_block_get_start(block) <= mem_block_get_free(block));

include/univ.i

@@ -308,11 +308,21 @@ typedef void* os_thread_ret_t;
 # define UNIV_MEM_INVALID(addr, size) VALGRIND_MAKE_MEM_UNDEFINED(addr, size)
 # define UNIV_MEM_FREE(addr, size) VALGRIND_MAKE_MEM_NOACCESS(addr, size)
 # define UNIV_MEM_ALLOC(addr, size) VALGRIND_MAKE_MEM_UNDEFINED(addr, size)
+# define UNIV_MEM_ASSERT_RW(addr, size) \
+	VALGRIND_CHECK_MEM_IS_DEFINED(addr, size)
+# define UNIV_MEM_ASSERT_W(addr, size) \
+	VALGRIND_CHECK_MEM_IS_ADDRESSABLE(addr, size)
 #else
 # define UNIV_MEM_VALID(addr, size) do {} while(0)
 # define UNIV_MEM_INVALID(addr, size) do {} while(0)
 # define UNIV_MEM_FREE(addr, size) do {} while(0)
 # define UNIV_MEM_ALLOC(addr, size) do {} while(0)
+# define UNIV_MEM_ASSERT_RW(addr, size) do {} while(0)
+# define UNIV_MEM_ASSERT_W(addr, size) do {} while(0)
 #endif
+#define UNIV_MEM_ASSERT_AND_FREE(addr, size) do {	\
+	UNIV_MEM_ASSERT_RW(addr, size);			\
+	UNIV_MEM_FREE(addr, size);			\
+} while (0)
 
 #endif

mem/mem0dbg.c

@@ -223,6 +223,8 @@ mem_init_buf(
 {
 	byte*	ptr;
 
+	UNIV_MEM_ASSERT_W(buf, n);
+
 	for (ptr = buf; ptr < buf + n; ptr++) {
 
 		if (ut_rnd_gen_ibool()) {
@@ -231,6 +233,8 @@ mem_init_buf(
 			*ptr = 0xBE;
 		}
 	}
+
+	UNIV_MEM_INVALID(buf, n);
 }
 
 /*******************************************************************
@@ -245,6 +249,8 @@ mem_erase_buf(
 {
 	byte*	ptr;
 
+	UNIV_MEM_ASSERT_W(buf, n);
+
 	for (ptr = buf; ptr < buf + n; ptr++) {
 		if (ut_rnd_gen_ibool()) {
 			*ptr = 0xDE;
@@ -252,6 +258,8 @@ mem_erase_buf(
 			*ptr = 0xAD;
 		}
 	}
+
+	UNIV_MEM_FREE(buf, n);
 }
 
 /*******************************************************************

mem/mem0mem.c

@@ -512,9 +512,9 @@ mem_heap_block_free(
 	of hex 0xDE and 0xAD. */
 
 	mem_erase_buf((byte*)block, len);
-
-#endif
-	UNIV_MEM_FREE(block, len);
+#else /* UNIV_MEM_DEBUG */
+	UNIV_MEM_ASSERT_AND_FREE(block, len);
+#endif /* UNIV_MEM_DEBUG */
 
 	if (init_block) {
 		/* Do not have to free: do nothing */