Improve memory debugging. This is follow-up to r1819.

mem_heap_validate(): Compile this function also if UNIV_MEM_DEBUG is
defined.  Previously, this function was only compiled with UNIV_DEBUG.

mem_heap_free_heap_top(): Flag the memory allocated, not freed, for
Valgrind.  Otherwise, Valgrind would complain on the second call of
mem_heap_empty().

UNIV_MEM_ASSERT_RW(), UNIV_MEM_ASSERT_W(): Display additional diagnostics
for failed Valgrind checks.

include/mem0dbg.h

@@ -60,6 +60,14 @@ mem_heap_validate_or_print(
 	ulint*		n_blocks); /* out: number of blocks in the heap,
 				if a NULL pointer is passed as this
 				argument, it is ignored */
+/******************************************************************
+Validates the contents of a memory heap. */
+
+ibool
+mem_heap_validate(
+/*==============*/
+				/* out: TRUE if ok */
+	mem_heap_t*   heap);	/* in: memory heap */
 #endif /* UNIV_MEM_DEBUG || UNIV_DEBUG */
 #ifdef UNIV_DEBUG
 /******************************************************************
@@ -71,14 +79,6 @@ mem_heap_check(
 				/* out: TRUE if ok */
 	mem_heap_t*   heap);	/* in: memory heap */
 #endif /* UNIV_DEBUG */
-/******************************************************************
-Validates the contents of a memory heap. */
-
-ibool
-mem_heap_validate(
-/*==============*/
-				/* out: TRUE if ok */
-	mem_heap_t*   heap);	/* in: memory heap */
 #ifdef UNIV_MEM_DEBUG
 /*********************************************************************
 TRUE if no memory is currently allocated. */

include/mem0mem.ic

@@ -278,8 +278,9 @@ mem_heap_free_heap_top(
 	mem_current_allocated_memory -= (total_size - size);
 	mutex_exit(&mem_hash_mutex);
 #else /* UNIV_MEM_DEBUG */
-	UNIV_MEM_ASSERT_AND_FREE(old_top, (byte*)block + block->len - old_top);
+	UNIV_MEM_ASSERT_W(old_top, (byte*)block + block->len - old_top);
 #endif /* UNIV_MEM_DEBUG */
+	UNIV_MEM_ALLOC(old_top, (byte*)block + block->len - old_top);
 
 	/* If free == start, we may free the block if it is not the first
 	one */

include/univ.i

@@ -308,10 +308,22 @@ 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)
+# define UNIV_MEM_ASSERT_RW(addr, size) do {				\
+	const void* _p = (const void*)					\
+		VALGRIND_CHECK_MEM_IS_DEFINED(addr, size);		\
+	if (UNIV_LIKELY_NULL(_p))					\
+		fprintf(stderr, "%p[%u] undefined at %d\n",		\
+			(const void*) (addr), (unsigned) (size),	\
+			((const char*) _p) - ((const char*) (addr)));	\
+	} while (0)
+# define UNIV_MEM_ASSERT_W(addr, size) do {				\
+	const void* _p = (const void*)					\
+		VALGRIND_CHECK_MEM_IS_ADDRESSABLE(addr, size);		\
+	if (UNIV_LIKELY_NULL(_p))					\
+		fprintf(stderr, "%p[%u] unwritable at %d\n",		\
+			(const void*) (addr), (unsigned) (size),	\
+			((const char*) _p) - ((const char*) (addr)));	\
+	} while (0)
 #else
 # define UNIV_MEM_VALID(addr, size) do {} while(0)
 # define UNIV_MEM_INVALID(addr, size) do {} while(0)

mem/mem0dbg.c

@@ -554,9 +554,7 @@ completed:
 	}
 	*error = FALSE;
 }
-#endif /* UNIV_MEM_DEBUG || UNIV_DEBUG */
 
-#ifdef UNIV_DEBUG
 /******************************************************************
 Prints the contents of a memory heap. */
 static
@@ -582,20 +580,6 @@ mem_heap_print(
 	ut_a(!error);
 }
 
-/******************************************************************
-Checks that an object is a memory heap (or a block of it). */
-
-ibool
-mem_heap_check(
-/*===========*/
-				/* out: TRUE if ok */
-	mem_heap_t*	heap)	/* in: memory heap */
-{
-	ut_a(heap->magic_n == MEM_BLOCK_MAGIC_N);
-
-	return(TRUE);
-}
-
 /******************************************************************
 Validates the contents of a memory heap. */
 
@@ -622,6 +606,22 @@ mem_heap_validate(
 
 	return(TRUE);
 }
+#endif /* UNIV_MEM_DEBUG || UNIV_DEBUG */
+
+#ifdef UNIV_DEBUG
+/******************************************************************
+Checks that an object is a memory heap (or a block of it). */
+
+ibool
+mem_heap_check(
+/*===========*/
+				/* out: TRUE if ok */
+	mem_heap_t*	heap)	/* in: memory heap */
+{
+	ut_a(heap->magic_n == MEM_BLOCK_MAGIC_N);
+
+	return(TRUE);
+}
 #endif /* UNIV_DEBUG */
 
 #ifdef UNIV_MEM_DEBUG