[Mesa-dev] [PATCH 1/6] draw: silence unused var warnings for non-debug build

[Jose Fonseca]

On 01/06/15 14:20, Brian Paul wrote:
> ---
>   src/gallium/auxiliary/draw/draw_llvm.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/src/gallium/auxiliary/draw/draw_llvm.c b/src/gallium/auxiliary/draw/draw_llvm.c
> index b9e55af..885c27c 100644
> --- a/src/gallium/auxiliary/draw/draw_llvm.c
> +++ b/src/gallium/auxiliary/draw/draw_llvm.c
> @@ -97,6 +97,7 @@ create_jit_dvbuffer_type(struct gallivm_state *gallivm,
>      dvbuffer_type = LLVMStructTypeInContext(gallivm->context, elem_types,
>                                              Elements(elem_types), 0);
>
> +   (void) target; /* silence unused var warning for non-debug build */
>      LP_CHECK_MEMBER_OFFSET(struct draw_vertex_buffer, map,
>                             target, dvbuffer_type,
>                             DRAW_JIT_DVBUFFER_MAP);
> @@ -133,6 +134,7 @@ create_jit_texture_type(struct gallivm_state *gallivm, const char *struct_name)
>      texture_type = LLVMStructTypeInContext(gallivm->context, elem_types,
>                                             Elements(elem_types), 0);
>
> +   (void) target; /* silence unused var warning for non-debug build */
>      LP_CHECK_MEMBER_OFFSET(struct draw_jit_texture, width,
>                             target, texture_type,
>                             DRAW_JIT_TEXTURE_WIDTH);
> @@ -290,6 +292,7 @@ create_gs_jit_context_type(struct gallivm_state *gallivm,
>      context_type = LLVMStructTypeInContext(gallivm->context, elem_types,
>                                             Elements(elem_types), 0);
>
> +   (void) target; /* silence unused var warning for non-debug build */
>      LP_CHECK_MEMBER_OFFSET(struct draw_gs_jit_context, constants,
>                             target, context_type, DRAW_GS_JIT_CTX_CONSTANTS);
>      LP_CHECK_MEMBER_OFFSET(struct draw_gs_jit_context, num_constants,
> @@ -353,6 +356,7 @@ create_jit_vertex_buffer_type(struct gallivm_state *gallivm,
>      vb_type = LLVMStructTypeInContext(gallivm->context, elem_types,
>                                        Elements(elem_types), 0);
>
> +   (void) target; /* silence unused var warning for non-debug build */
>      LP_CHECK_MEMBER_OFFSET(struct pipe_vertex_buffer, stride,
>                             target, vb_type, 0);
>      LP_CHECK_MEMBER_OFFSET(struct pipe_vertex_buffer, buffer_offset,
>


Series LGTM.

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


The reasons these warnings are popping up is because we're using 
system's assert macro, instead of src/gallium/auxiliary/util/u_debug.h

src/gallium/auxiliary/util/u_debug.h have two advantages over system's 
assert macro:

1. it avoids these unused variable warnings because the non-debug 
version includes the expression:

   #define debug_assert(expr) (void)(0 && (expr))

2. On windows it will dump the assert failure message as 
stderr/OutputDebugMessage (instead of a MessageBox.)

That said, I agree that trying to override system's assert is unsustainable.

Your series addresses issue 1.  For issue 2, it might be worthwhile to 
override the _assert/_wassert built-in implementations instead.  This is 
the approach I recently did on Apitrace and it seems to work just as well:

   https://github.com/apitrace/apitrace/blob/master/wrappers/assert.cpp


This is not urgent.  But if you find yourself wondering why assertion 
failure messages don't appear on logs,  it might be worth doing it.


Jose