[Mesa-dev] [PATCH 2/4] util: add debug_memory_check_block(), debug_memory_tag()

[Jose Fonseca]

----- Original Message -----
> The former just checks that the given block is valid by checking
> the header and footer.
> 
> The later sets the memory block's tag.  With extra debug code, we
> can use that for monitoring/checking particular allocations.
> ---
>  src/gallium/auxiliary/os/os_memory_debug.h  |    6 +++
>  src/gallium/auxiliary/util/u_debug_memory.c |   55
>  +++++++++++++++++++++++++++
>  2 files changed, 61 insertions(+), 0 deletions(-)
> 
> diff --git a/src/gallium/auxiliary/os/os_memory_debug.h
> b/src/gallium/auxiliary/os/os_memory_debug.h
> index 36b8fc6..9a487de 100644
> --- a/src/gallium/auxiliary/os/os_memory_debug.h
> +++ b/src/gallium/auxiliary/os/os_memory_debug.h
> @@ -60,6 +60,12 @@ void *
>  debug_realloc(const char *file, unsigned line, const char *function,
>                void *old_ptr, size_t old_size, size_t new_size );
>  
> +void
> +debug_memory_tag(void *ptr, unsigned tag);
> +
> +void
> +debug_memory_check_block(void *ptr);
> +
>  void
>  debug_memory_check(void);
>  
> diff --git a/src/gallium/auxiliary/util/u_debug_memory.c
> b/src/gallium/auxiliary/util/u_debug_memory.c
> index 4bf26a5..4723547 100644
> --- a/src/gallium/auxiliary/util/u_debug_memory.c
> +++ b/src/gallium/auxiliary/util/u_debug_memory.c
> @@ -76,6 +76,7 @@ struct debug_memory_header
>  #endif
>  
>     unsigned magic;
> +   unsigned tag;

Long term, I think a "const char * tag" would be handier -- it could be used in the debug messages.

>  };
>  
>  struct debug_memory_footer
> @@ -140,6 +141,7 @@ debug_malloc(const char *file, unsigned line, const char
> *function,
>     hdr->function = function;
>     hdr->size = size;
>     hdr->magic = DEBUG_MEMORY_MAGIC;
> +   hdr->tag = 0;
>  #if DEBUG_FREED_MEMORY
>     hdr->freed = FALSE;
>  #endif
> @@ -263,6 +265,7 @@ debug_realloc(const char *file, unsigned line, const char
> *function,
>     new_hdr->function = old_hdr->function;
>     new_hdr->size = new_size;
>     new_hdr->magic = DEBUG_MEMORY_MAGIC;
> +   new_hdr->tag = 0;
>  #if DEBUG_FREED_MEMORY
>     new_hdr->freed = FALSE;
>  #endif
> @@ -348,6 +351,58 @@ debug_memory_end(unsigned long start_no)
>  
>  
>  /**
> + * Put a tag (arbitrary integer) on a memory block.
> + * Can be useful for debugging.
> + */
> +void
> +debug_memory_tag(void *ptr, unsigned tag)
> +{
> +   struct debug_memory_header *hdr;
> +
> +   if (!ptr)
> +      return;
> +
> +   hdr = header_from_data(ptr);
> +   if (hdr->magic != DEBUG_MEMORY_MAGIC) {
> +      debug_printf("%s corrupted memory at %p\n", __FUNCTION__, ptr);
> +      debug_assert(0);
> +   }
> +
> +   hdr->tag = tag;
> +}
> +
> +
> +/**
> + * Check the given block of memory for validity/corruption.
> + */
> +void
> +debug_memory_check_block(void *ptr)
> +{
> +   struct debug_memory_header *hdr;
> +   struct debug_memory_footer *ftr;
> +
> +   if (!ptr)
> +      return;
> +
> +   hdr = header_from_data(ptr);
> +   ftr = footer_from_header(hdr);
> +
> +   if (hdr->magic != DEBUG_MEMORY_MAGIC) {
> +      debug_printf("%s:%u:%s: bad or corrupted memory %p\n",
> +                   hdr->file, hdr->line, hdr->function, ptr);
> +      debug_assert(0);
> +   }
> +
> +   if (ftr->magic != DEBUG_MEMORY_MAGIC) {
> +      debug_printf("%s:%u:%s: buffer overflow %p\n",
> +                   hdr->file, hdr->line, hdr->function, ptr);
> +      debug_assert(0);
> +   }
> +}
> +
> +
> +
> +/**
>   * We can periodically call this from elsewhere to do a basic sanity
>   * check of the heap memory we've allocated.
>   */
>


Reviewed-by: Jose Fonseca <jfonseca at vmware.com>