evas_gl_context: fix dereference after null check

From the following commit every *_push function has used
evas_gl_common_shader_program_get which could set prog to NULL.

   38ad8fd Evas GL: Implement runtime generation and load of shaders

   @@ -1781,28 +1618,26 @@ evas_gl_common_context_line_push(Evas_Engine_GL_Context *gc,
                                     int r, int g, int b, int a)

   +   prog = evas_gl_common_shader_program_get(gc, SHD_LINE, NULL, 0, r, g, b, a,
   +                                            0, 0, 0, 0, EINA_FALSE, NULL, EINA_FALSE,
   +                                            mtex, mask_smooth, mw, mh, NULL, NULL, &masksam);

   -   prog = gc->shared->shader[shader].prog;

   @@ -3114,20 +2919,23 @@ shader_array_flush(Evas_Engine_GL_Context *gc)

   +        Evas_GL_Program *prog;
   +
            if (gc->pipe[i].array.num <= 0) break;

   +        prog = gc->pipe[i].shader.prog;
            setclip = EINA_FALSE;
            pipe_done++;
            gc->flushnum++;

            GLERRV("<flush err>");
   -        if (gc->pipe[i].shader.cur_prog != gc->state.current.cur_prog)
   +        if (prog && (prog != gc->state.current.prog))

This is pretty unexpected and unusual case should not exist.
But I would like to update evas_gl_context to make system reliable.

@tizen_fix

Change-Id: Iacdb3f60d73b9fdbf44e129c74da7f034ba3ce7b

diff --git a/src/modules/evas/engines/gl_common/evas_gl_context.c b/src/modules/evas/engines/gl_common/evas_gl_context.c
index c153f5b..f97a712 100644 (file)
--- a/src/modules/evas/engines/gl_common/evas_gl_context.c
+++ b/src/modules/evas/engines/gl_common/evas_gl_context.c
@@ -4672,8 +4672,11 @@ _orig_shader_array_flush(Evas_Engine_GL_Context *gc)
              // TIZEN ONLY (20180823): Use PIO for Paletted png
              if(gc->pipe[i].array.use_palette)
                {
-                  GL_TH(glUniform1f, prog->uniform.xDerivativeloc ,gc->pipe[i].shader.palette.xDerivative);
-                  GL_TH(glUniform1f, prog->uniform.yDerivativeloc ,gc->pipe[i].shader.palette.yDerivative);
+                  if (prog)
+                    {
+                       GL_TH(glUniform1f, prog->uniform.xDerivativeloc ,gc->pipe[i].shader.palette.xDerivative);
+                       GL_TH(glUniform1f, prog->uniform.yDerivativeloc ,gc->pipe[i].shader.palette.yDerivative);
+                    }
                   GL_TH(glActiveTexture, ACTIVE_TEXTURE);
                   GL_TH(glBindTexture, GL_TEXTURE_2D, gc->pipe[i].shader.palette.cur_texp);