[Mesa-dev] [BUG]: calloc (nmemb=1, size=0)

[Lucas Stach]

Am Freitag, den 03.08.2012, 07:57 +0200 schrieb Johann Klammer:
> Hello,
> 
> I tried to replace the memory allocator for a program
> linked against mesa. With the libc allocators the app shows some 
> textured and shaded triangles, but with the custom allocators, it's all 
> black triangles. Sorry, I cannot post the program source as it is rather 
> large, but will try to come up with a minimal test if this is necessary.
> 
> The custom allocator returns NULL for zero-sized requests.
> The problem goes away if I change the allocator to return some memory.
> 
> Mesa Version: 8.0.3
> 
> Symptoms:
> all black triangles.
> 
> The relevant snippet seems to be:
> 
> 4674  t->immediates = (struct ureg_src *)CALLOC(program->num_immediates 
> * sizeof(struct ureg_src));
> 4675  if (t->immediates == NULL) {
> 4676  ret = PIPE_ERROR_OUT_OF_MEMORY;
> 4677  goto out;
> 4678  }
> 
[...]

Does the patch below help?

--
From: Lucas Stach <dev at lynxeye.de>
Date: Fri, 3 Aug 2012 12:55:20 +0200
Subject: [PATCH] st/mesa: fix immediate emission with custom allocator

---
 src/mesa/state_tracker/st_glsl_to_tgsi.cpp | 24 +++++++++++++-----------
 1 Datei geändert, 13 Zeilen hinzugefügt(+), 11 Zeilen entfernt(-)

diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
index fcd69b1..f426f45 100644
--- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
+++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
@@ -4714,18 +4714,20 @@ st_translate_program(
    
    /* Emit immediate values.
     */
-   t->immediates = (struct ureg_src *)CALLOC(program->num_immediates * sizeof(struct ureg_src));
-   if (t->immediates == NULL) {
-      ret = PIPE_ERROR_OUT_OF_MEMORY;
-      goto out;
-   }
-   i = 0;
-   foreach_iter(exec_list_iterator, iter, program->immediates) {
-      immediate_storage *imm = (immediate_storage *)iter.get();
-      assert(i < program->num_immediates);
-      t->immediates[i++] = emit_immediate(t, imm->values, imm->type, imm->size);
+   if (program->num_immediates) {
+      t->immediates = (struct ureg_src *)CALLOC(program->num_immediates * sizeof(struct ureg_src));
+      if (t->immediates == NULL) {
+         ret = PIPE_ERROR_OUT_OF_MEMORY;
+         goto out;
+      }
+      i = 0;
+      foreach_iter(exec_list_iterator, iter, program->immediates) {
+         immediate_storage *imm = (immediate_storage *)iter.get();
+         assert(i < program->num_immediates);
+         t->immediates[i++] = emit_immediate(t, imm->values, imm->type, imm->size);
+      }
+      assert(i == program->num_immediates);
    }
-   assert(i == program->num_immediates);
 
    /* texture samplers */
    for (i = 0; i < ctx->Const.MaxTextureImageUnits; i++) {
-- 
1.7.11.2