[Mesa-dev] [PATCH V2] Modified _mesa_align_free to have consistent behavior when dealing with NULL memory address.

[Siavash Eliasi]

Revision 2:
- Avoiding compile error on MSVC and possible warnings on other compilers.
- Added comment regards passing NULL pointer being safe.
---
 src/mesa/main/imports.c                | 14 +++++++++-----
 src/mesa/math/m_matrix.c               | 13 +++++--------
 src/mesa/program/prog_parameter.c      |  3 +--
 src/mesa/state_tracker/st_cb_texture.c |  6 ++----
 src/mesa/swrast/s_texture.c            |  7 +++----
 src/mesa/tnl/t_vertex.c                |  6 ++----
 src/mesa/vbo/vbo_exec_api.c            |  9 ++++-----
 7 files changed, 26 insertions(+), 32 deletions(-)

diff --git a/src/mesa/main/imports.c b/src/mesa/main/imports.c
index 277e947..4afe156 100644
--- a/src/mesa/main/imports.c
+++ b/src/mesa/main/imports.c
@@ -168,6 +168,8 @@ _mesa_align_calloc(size_t bytes, unsigned long alignment)
  * \param ptr pointer to the memory to be freed.
  * The actual address to free is stored in the word immediately before the
  * address the client sees.
+ * Note that it is legal to pass NULL pointer to this function and will be
+ * handled accordingly.
  */
 void
 _mesa_align_free(void *ptr)
@@ -177,9 +179,11 @@ _mesa_align_free(void *ptr)
 #elif defined(_WIN32) && defined(_MSC_VER)
    _aligned_free(ptr);
 #else
-   void **cubbyHole = (void **) ((char *) ptr - sizeof(void *));
-   void *realAddr = *cubbyHole;
-   free(realAddr);
+   if (ptr) {
+      void **cubbyHole = (void **) ((char *) ptr - sizeof(void *));
+      void *realAddr = *cubbyHole;
+      free(realAddr);
+   }
 #endif /* defined(HAVE_POSIX_MEMALIGN) */
 }
 
@@ -199,8 +203,8 @@ _mesa_align_realloc(void *oldBuffer, size_t oldSize, size_t newSize,
    if (newBuf && oldBuffer && copySize > 0) {
       memcpy(newBuf, oldBuffer, copySize);
    }
-   if (oldBuffer)
-      _mesa_align_free(oldBuffer);
+
+   _mesa_align_free(oldBuffer);
    return newBuf;
 #endif
 }
diff --git a/src/mesa/math/m_matrix.c b/src/mesa/math/m_matrix.c
index 2902315..274f969 100644
--- a/src/mesa/math/m_matrix.c
+++ b/src/mesa/math/m_matrix.c
@@ -1488,14 +1488,11 @@ _math_matrix_ctr( GLmatrix *m )
 void
 _math_matrix_dtr( GLmatrix *m )
 {
-   if (m->m) {
-      _mesa_align_free( m->m );
-      m->m = NULL;
-   }
-   if (m->inv) {
-      _mesa_align_free( m->inv );
-      m->inv = NULL;
-   }
+   _mesa_align_free( m->m );
+   m->m = NULL;
+
+   _mesa_align_free( m->inv );
+   m->inv = NULL;
 }
 
 /*@}*/
diff --git a/src/mesa/program/prog_parameter.c b/src/mesa/program/prog_parameter.c
index 4d9cf08..54531d2 100644
--- a/src/mesa/program/prog_parameter.c
+++ b/src/mesa/program/prog_parameter.c
@@ -83,8 +83,7 @@ _mesa_free_parameter_list(struct gl_program_parameter_list *paramList)
       free((void *)paramList->Parameters[i].Name);
    }
    free(paramList->Parameters);
-   if (paramList->ParameterValues)
-      _mesa_align_free(paramList->ParameterValues);
+   _mesa_align_free(paramList->ParameterValues);
    free(paramList);
 }
 
diff --git a/src/mesa/state_tracker/st_cb_texture.c b/src/mesa/state_tracker/st_cb_texture.c
index faa9ee3..f33d3cf 100644
--- a/src/mesa/state_tracker/st_cb_texture.c
+++ b/src/mesa/state_tracker/st_cb_texture.c
@@ -175,10 +175,8 @@ st_FreeTextureImageBuffer(struct gl_context *ctx,
       pipe_resource_reference(&stImage->pt, NULL);
    }
 
-   if (stImage->TexData) {
-      _mesa_align_free(stImage->TexData);
-      stImage->TexData = NULL;
-   }
+   _mesa_align_free(stImage->TexData);
+   stImage->TexData = NULL;
 }
 
 
diff --git a/src/mesa/swrast/s_texture.c b/src/mesa/swrast/s_texture.c
index 27803c5..c08a4e9 100644
--- a/src/mesa/swrast/s_texture.c
+++ b/src/mesa/swrast/s_texture.c
@@ -164,10 +164,9 @@ _swrast_free_texture_image_buffer(struct gl_context *ctx,
                                   struct gl_texture_image *texImage)
 {
    struct swrast_texture_image *swImage = swrast_texture_image(texImage);
-   if (swImage->Buffer) {
-      _mesa_align_free(swImage->Buffer);
-      swImage->Buffer = NULL;
-   }
+
+   _mesa_align_free(swImage->Buffer);
+   swImage->Buffer = NULL;
 
    free(swImage->ImageSlices);
    swImage->ImageSlices = NULL;
diff --git a/src/mesa/tnl/t_vertex.c b/src/mesa/tnl/t_vertex.c
index c7a745e..8c4195e 100644
--- a/src/mesa/tnl/t_vertex.c
+++ b/src/mesa/tnl/t_vertex.c
@@ -546,10 +546,8 @@ void _tnl_free_vertices( struct gl_context *ctx )
       struct tnl_clipspace *vtx = GET_VERTEX_STATE(ctx);
       struct tnl_clipspace_fastpath *fp, *tmp;
 
-      if (vtx->vertex_buf) {
-         _mesa_align_free(vtx->vertex_buf);
-         vtx->vertex_buf = NULL;
-      }
+      _mesa_align_free(vtx->vertex_buf);
+      vtx->vertex_buf = NULL;
 
       for (fp = vtx->fastpath ; fp ; fp = tmp) {
          tmp = fp->next;
diff --git a/src/mesa/vbo/vbo_exec_api.c b/src/mesa/vbo/vbo_exec_api.c
index 600398c..f3c41e0 100644
--- a/src/mesa/vbo/vbo_exec_api.c
+++ b/src/mesa/vbo/vbo_exec_api.c
@@ -989,11 +989,10 @@ void vbo_use_buffer_objects(struct gl_context *ctx)
 
    /* Make sure this func is only used once */
    assert(exec->vtx.bufferobj == ctx->Shared->NullBufferObj);
-   if (exec->vtx.buffer_map) {
-      _mesa_align_free(exec->vtx.buffer_map);
-      exec->vtx.buffer_map = NULL;
-      exec->vtx.buffer_ptr = NULL;
-   }
+
+   _mesa_align_free(exec->vtx.buffer_map);
+   exec->vtx.buffer_map = NULL;
+   exec->vtx.buffer_ptr = NULL;
 
    /* Allocate a real buffer object now */
    _mesa_reference_buffer_object(ctx, &exec->vtx.bufferobj, NULL);
-- 
1.8.4.2