mesa: fix GLSL program objects with more than 16 samplers combined

The problem is the sampler units are allocated from the same pool for all
shader stages, so if a vertex shader uses 12 samplers (0..11), the fragment
shader samplers start at index 12, leaving only 4 sampler units
for the fragment shader. The main cause is probably the fact that samplers
(texture unit -> sampler unit mapping, etc.) are tracked globally
for an entire program object.

This commit adapts the GLSL linker and core Mesa such that the sampler units
are assigned to sampler uniforms for each shader stage separately
(if a sampler uniform is used in all shader stages, it may occupy a different
sampler unit in each, and vice versa, an i-th sampler unit may refer to
a different sampler uniform in each shader stage), and the sampler-specific
variables are moved from gl_shader_program to gl_shader.

This doesn't require any driver changes, and it fixes piglit/max-samplers
for gallium and classic swrast. It also works with any number of shader
stages.

v2: - converted tabs to spaces
    - added an assertion to _mesa_get_sampler_uniform_value

Reviewed-by: Ian Romanick <[email protected]>
Reviewed-by: Eric Anholt <[email protected]>

1 files changed, 62 insertions, 64 deletions

diff --git a/src/glsl/link_uniforms.cpp b/src/glsl/link_uniforms.cpp
index d457e4d0cd9..04218be7ac9 100644
--- a/src/glsl/link_uniforms.cpp
+++ b/src/glsl/link_uniforms.cpp
@@ -263,15 +263,19 @@ public:
    parcel_out_uniform_storage(struct string_to_uint_map *map,
 			      struct gl_uniform_storage *uniforms,
 			      union gl_constant_value *values)
-      : map(map), uniforms(uniforms), next_sampler(0), values(values)
+      : map(map), uniforms(uniforms), values(values)
    {
-      memset(this->targets, 0, sizeof(this->targets));
    }
 
-   void start_shader()
+   void start_shader(gl_shader_type shader_type)
    {
+      assert(shader_type < MESA_SHADER_TYPES);
+      this->shader_type = shader_type;
+
       this->shader_samplers_used = 0;
       this->shader_shadow_samplers = 0;
+      this->next_sampler = 0;
+      memset(this->targets, 0, sizeof(this->targets));
    }
 
    void set_and_process(struct gl_shader_program *prog,
@@ -335,8 +339,37 @@ public:
    int ubo_block_index;
    int ubo_byte_offset;
    bool ubo_row_major;
+   gl_shader_type shader_type;
 
 private:
+   void handle_samplers(const glsl_type *base_type,
+                        struct gl_uniform_storage *uniform)
+   {
+      if (base_type->is_sampler()) {
+         uniform->sampler[shader_type].index = this->next_sampler;
+         uniform->sampler[shader_type].active = true;
+
+         /* Increment the sampler by 1 for non-arrays and by the number of
+          * array elements for arrays.
+          */
+         this->next_sampler +=
+               MAX2(1, uniform->array_elements);
+
+         const gl_texture_index target = base_type->sampler_index();
+         const unsigned shadow = base_type->sampler_shadow;
+         for (unsigned i = uniform->sampler[shader_type].index;
+              i < MIN2(this->next_sampler, MAX_SAMPLERS);
+              i++) {
+            this->targets[i] = target;
+            this->shader_samplers_used |= 1U << i;
+            this->shader_shadow_samplers |= shadow << i;
+         }
+      } else {
+         uniform->sampler[shader_type].index = ~0;
+         uniform->sampler[shader_type].active = false;
+      }
+   }
+
    virtual void visit_field(const glsl_type *type, const char *name,
                             bool row_major)
    {
@@ -354,31 +387,6 @@ private:
       if (!found)
 	 return;
 
-      /* If there is already storage associated with this uniform, it means
-       * that it was set while processing an earlier shader stage.  For
-       * example, we may be processing the uniform in the fragment shader, but
-       * the uniform was already processed in the vertex shader.
-       */
-      if (this->uniforms[id].storage != NULL) {
-	 /* If the uniform already has storage set from another shader stage,
-	  * mark the samplers used for this shader stage.
-	  */
-	 if (type->contains_sampler()) {
-	    const unsigned count = MAX2(1, this->uniforms[id].array_elements);
-	    const unsigned shadow = (type->is_array())
-	       ? type->fields.array->sampler_shadow : type->sampler_shadow;
-
-	    for (unsigned i = 0; i < count; i++) {
-	       const unsigned s = this->uniforms[id].sampler + i;
-
-	       this->shader_samplers_used |= 1U << s;
-	       this->shader_shadow_samplers |= shadow << s;
-	    }
-	 }
-
-	 return;
-      }
-
       const glsl_type *base_type;
       if (type->is_array()) {
 	 this->uniforms[id].array_elements = type->length;
@@ -388,26 +396,16 @@ private:
 	 base_type = type;
       }
 
-      if (base_type->is_sampler()) {
-	 this->uniforms[id].sampler = this->next_sampler;
+      /* This assigns sampler uniforms to sampler units. */
+      handle_samplers(base_type, &this->uniforms[id]);
 
-	 /* Increment the sampler by 1 for non-arrays and by the number of
-	  * array elements for arrays.
-	  */
-	 this->next_sampler += MAX2(1, this->uniforms[id].array_elements);
-
-	 const gl_texture_index target = base_type->sampler_index();
-	 const unsigned shadow = base_type->sampler_shadow;
-	 for (unsigned i = this->uniforms[id].sampler
-		 ; i < MIN2(this->next_sampler, MAX_SAMPLERS)
-		 ; i++) {
-	    this->targets[i] = target;
-	    this->shader_samplers_used |= 1U << i;
-	    this->shader_shadow_samplers |= shadow << i;
-	 }
-
-      } else {
-	 this->uniforms[id].sampler = ~0;
+      /* If there is already storage associated with this uniform, it means
+       * that it was set while processing an earlier shader stage.  For
+       * example, we may be processing the uniform in the fragment shader, but
+       * the uniform was already processed in the vertex shader.
+       */
+      if (this->uniforms[id].storage != NULL) {
+         return;
       }
 
       this->uniforms[id].name = ralloc_strdup(this->uniforms, name);
@@ -633,17 +631,6 @@ link_assign_uniform_locations(struct gl_shader_program *prog)
       prog->UniformHash = new string_to_uint_map;
    }
 
-   /* Uniforms that lack an initializer in the shader code have an initial
-    * value of zero.  This includes sampler uniforms.
-    *
-    * Page 24 (page 30 of the PDF) of the GLSL 1.20 spec says:
-    *
-    *     "The link time initial value is either the value of the variable's
-    *     initializer, if present, or 0 if no initializer is present. Sampler
-    *     types cannot have initializers."
-    */
-   memset(prog->SamplerUnits, 0, sizeof(prog->SamplerUnits));
-
    /* First pass: Count the uniform resources used by the user-defined
     * uniforms.  While this happens, each active uniform will have an index
     * assigned to it.
@@ -656,6 +643,18 @@ link_assign_uniform_locations(struct gl_shader_program *prog)
       if (prog->_LinkedShaders[i] == NULL)
 	 continue;
 
+      /* Uniforms that lack an initializer in the shader code have an initial
+       * value of zero.  This includes sampler uniforms.
+       *
+       * Page 24 (page 30 of the PDF) of the GLSL 1.20 spec says:
+       *
+       *     "The link time initial value is either the value of the variable's
+       *     initializer, if present, or 0 if no initializer is present. Sampler
+       *     types cannot have initializers."
+       */
+      memset(prog->_LinkedShaders[i]->SamplerUnits, 0,
+             sizeof(gl_shader::SamplerUnits));
+
       link_update_uniform_buffer_variables(prog->_LinkedShaders[i]);
 
       /* Reset various per-shader target counts.
@@ -706,9 +705,7 @@ link_assign_uniform_locations(struct gl_shader_program *prog)
       if (prog->_LinkedShaders[i] == NULL)
 	 continue;
 
-      /* Reset various per-shader target counts.
-       */
-      parcel.start_shader();
+      parcel.start_shader((gl_shader_type)i);
 
       foreach_list(node, prog->_LinkedShaders[i]->ir) {
 	 ir_variable *const var = ((ir_instruction *) node)->as_variable();
@@ -726,10 +723,11 @@ link_assign_uniform_locations(struct gl_shader_program *prog)
 
       prog->_LinkedShaders[i]->active_samplers = parcel.shader_samplers_used;
       prog->_LinkedShaders[i]->shadow_samplers = parcel.shader_shadow_samplers;
-   }
 
-   assert(sizeof(prog->SamplerTargets) == sizeof(parcel.targets));
-   memcpy(prog->SamplerTargets, parcel.targets, sizeof(prog->SamplerTargets));
+      assert(sizeof(gl_shader::SamplerTargets) == sizeof(parcel.targets));
+      memcpy(prog->_LinkedShaders[i]->SamplerTargets, parcel.targets,
+             sizeof(gl_shader::SamplerTargets));
+   }
 
 #ifndef NDEBUG
    for (unsigned i = 0; i < num_user_uniforms; i++) {