i965/gen6/gs: Fix binding table clash between TF surfaces and textures.

For gen6 geometry shaders we use the first BRW_MAX_SOL_BINDINGS entries of the
binding table for transform feedback surfaces. However, vec4_visitor will
setup the binding table so that textures use the same space in the binding
table. This is done when calling assign_common_binding_table_offsets(0) as
part if its run() method.

To fix this clash we add a virtual method to the vec4_visitor hierarchy to
assign the binding table offsets, so that we can change this behavior
specifically for gen6 geometry shaders by mapping textures right after the
first BRW_MAX_SOL_BINDINGS entries.

Also, when there is no user-provided geometry shader, we only need to upload
the binding table if we have transform feedback, however, in the case of a
user-provided geometry shader, we can't only look into transform feedback
to make that decision.

This fixes multiple piglit tests for textureSize() and texelFetch() when these
functions are called from a geometry shader in gen6, like these:

bin/textureSize gs sampler2D -fbo -auto
bin/texelFetch gs usampler2D -fbo -auto

Acked-by: Kenneth Graunke <[email protected]>
Reviewed-by: Jordan Justen <[email protected]>

6 files changed, 78 insertions, 29 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_context.h b/src/mesa/drivers/dri/i965/brw_context.h
index 3bdc4806163..377853ed96d 100644
--- a/src/mesa/drivers/dri/i965/brw_context.h
+++ b/src/mesa/drivers/dri/i965/brw_context.h
@@ -600,7 +600,6 @@ struct brw_vs_prog_data {
                             2 /* shader time, pull constants */)
 
 #define SURF_INDEX_GEN6_SOL_BINDING(t) (t)
-#define BRW_MAX_GEN6_GS_SURFACES       SURF_INDEX_GEN6_SOL_BINDING(BRW_MAX_SOL_BINDINGS)
 
 /* Note: brw_gs_prog_data_compare() must be updated when adding fields to
  * this struct!
@@ -1260,7 +1259,12 @@ struct brw_context
       uint32_t state_offset;
 
       uint32_t bind_bo_offset;
-      uint32_t surf_offset[BRW_MAX_GEN6_GS_SURFACES];
+      /**
+       * Surface offsets for the binding table. We only need surfaces to
+       * implement transform feedback so BRW_MAX_SOL_BINDINGS is all that we
+       * need in this case.
+       */
+      uint32_t surf_offset[BRW_MAX_SOL_BINDINGS];
    } ff_gs;
 
    struct {
diff --git a/src/mesa/drivers/dri/i965/brw_vec4.cpp b/src/mesa/drivers/dri/i965/brw_vec4.cpp
index 4210ee00a54..d5180263010 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4.cpp
@@ -1612,6 +1612,12 @@ vec4_vs_visitor::setup_payload(void)
    this->first_non_payload_grf = reg;
 }
 
+void
+vec4_visitor::assign_binding_table_offsets()
+{
+   assign_common_binding_table_offsets(0);
+}
+
 src_reg
 vec4_visitor::get_timestamp()
 {
@@ -1711,7 +1717,7 @@ vec4_visitor::run()
    if (INTEL_DEBUG & DEBUG_SHADER_TIME)
       emit_shader_time_begin();
 
-   assign_common_binding_table_offsets(0);
+   assign_binding_table_offsets();
 
    emit_prolog();
 
diff --git a/src/mesa/drivers/dri/i965/brw_vec4.h b/src/mesa/drivers/dri/i965/brw_vec4.h
index 1909cbd75d6..69faa740cb2 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4.h
+++ b/src/mesa/drivers/dri/i965/brw_vec4.h
@@ -589,6 +589,7 @@ protected:
    void setup_payload_interference(struct ra_graph *g, int first_payload_node,
                                    int reg_node_count);
    virtual dst_reg *make_reg_for_system_value(ir_variable *ir) = 0;
+   virtual void assign_binding_table_offsets();
    virtual void setup_payload() = 0;
    virtual void emit_prolog() = 0;
    virtual void emit_program_code() = 0;
diff --git a/src/mesa/drivers/dri/i965/gen6_gs_visitor.cpp b/src/mesa/drivers/dri/i965/gen6_gs_visitor.cpp
index 704a02f9c3b..d16cc6ed8b7 100644
--- a/src/mesa/drivers/dri/i965/gen6_gs_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/gen6_gs_visitor.cpp
@@ -36,6 +36,15 @@ const unsigned MAX_GS_INPUT_VERTICES = 6;
 namespace brw {
 
 void
+gen6_gs_visitor::assign_binding_table_offsets()
+{
+   /* In gen6 we reserve the first BRW_MAX_SOL_BINDINGS entries for transform
+    * feedback surfaces.
+    */
+   assign_common_binding_table_offsets(BRW_MAX_SOL_BINDINGS);
+}
+
+void
 gen6_gs_visitor::emit_prolog()
 {
    vec4_gs_visitor::emit_prolog();
diff --git a/src/mesa/drivers/dri/i965/gen6_gs_visitor.h b/src/mesa/drivers/dri/i965/gen6_gs_visitor.h
index d29afdb3f11..28f23c9e4f7 100644
--- a/src/mesa/drivers/dri/i965/gen6_gs_visitor.h
+++ b/src/mesa/drivers/dri/i965/gen6_gs_visitor.h
@@ -43,6 +43,7 @@ public:
       vec4_gs_visitor(brw, c, prog, mem_ctx, no_spills) {}
 
 protected:
+   virtual void assign_binding_table_offsets();
    virtual void emit_prolog();
    virtual void emit_thread_end();
    virtual void visit(ir_emit_vertex *);
diff --git a/src/mesa/drivers/dri/i965/gen6_sol.c b/src/mesa/drivers/dri/i965/gen6_sol.c
index d21a01037f1..997db1a891f 100644
--- a/src/mesa/drivers/dri/i965/gen6_sol.c
+++ b/src/mesa/drivers/dri/i965/gen6_sol.c
@@ -108,48 +108,76 @@ static void
 brw_gs_upload_binding_table(struct brw_context *brw)
 {
    uint32_t *bind;
+   struct gl_context *ctx = &brw->ctx;
+   const struct gl_shader_program *shaderprog;
+   bool need_binding_table = false;
+
+   /* We have two scenarios here:
+    * 1) We are using a geometry shader only to implement transform feedback
+    *    for a vertex shader (brw->geometry_program == NULL). In this case, we
+    *    only need surfaces for transform feedback in the GS stage.
+    * 2) We have a user-provided geometry shader. In this case we may need
+    *    surfaces for transform feedback and/or other stuff, like textures,
+    *    in the GS stage.
+    */
 
    if (!brw->geometry_program) {
-      struct gl_context *ctx = &brw->ctx;
       /* BRW_NEW_VERTEX_PROGRAM */
-      const struct gl_shader_program *shaderprog =
-         ctx->_Shader->CurrentProgram[MESA_SHADER_VERTEX];
-      bool has_surfaces = false;
-
+      shaderprog = ctx->_Shader->CurrentProgram[MESA_SHADER_VERTEX];
       if (shaderprog) {
+         /* Skip making a binding table if we don't have anything to put in it */
          const struct gl_transform_feedback_info *linked_xfb_info =
             &shaderprog->LinkedTransformFeedback;
-         /* Currently we only ever upload surfaces for SOL. */
-         has_surfaces = linked_xfb_info->NumOutputs != 0;
-
-         /* Skip making a binding table if we don't have anything to put in it. */
-         if (!has_surfaces) {
-            if (brw->ff_gs.bind_bo_offset != 0) {
-               brw->state.dirty.brw |= BRW_NEW_GS_BINDING_TABLE;
-               brw->ff_gs.bind_bo_offset = 0;
-            }
-            return;
+         need_binding_table = linked_xfb_info->NumOutputs > 0;
+      }
+      if (!need_binding_table) {
+         if (brw->ff_gs.bind_bo_offset != 0) {
+            brw->state.dirty.brw |= BRW_NEW_GS_BINDING_TABLE;
+            brw->ff_gs.bind_bo_offset = 0;
          }
+         return;
       }
-   }
 
-   /* Might want to calculate nr_surfaces first, to avoid taking up so much
-    * space for the binding table.
-    */
-   if (brw->geometry_program) {
+      /* Might want to calculate nr_surfaces first, to avoid taking up so much
+       * space for the binding table. Anyway, in this case we know that we only
+       * use BRW_MAX_SOL_BINDINGS surfaces at most.
+       */
       bind = brw_state_batch(brw, AUB_TRACE_BINDING_TABLE,
-                             sizeof(uint32_t) * BRW_MAX_GEN6_GS_SURFACES,
-                             32, &brw->gs.base.bind_bo_offset);
+                             sizeof(uint32_t) * BRW_MAX_SOL_BINDINGS,
+                             32, &brw->ff_gs.bind_bo_offset);
 
       /* BRW_NEW_SURFACES */
-      memcpy(bind, brw->gs.base.surf_offset, BRW_MAX_GEN6_GS_SURFACES * sizeof(uint32_t));
+      memcpy(bind, brw->ff_gs.surf_offset,
+             BRW_MAX_SOL_BINDINGS * sizeof(uint32_t));
    } else {
+      /* BRW_NEW_GEOMETRY_PROGRAM */
+      shaderprog = ctx->_Shader->CurrentProgram[MESA_SHADER_GEOMETRY];
+      if (shaderprog) {
+         /* Skip making a binding table if we don't have anything to put in it */
+         struct brw_stage_prog_data *prog_data = brw->gs.base.prog_data;
+         const struct gl_transform_feedback_info *linked_xfb_info =
+            &shaderprog->LinkedTransformFeedback;
+         need_binding_table = linked_xfb_info->NumOutputs > 0 ||
+                              prog_data->binding_table.size_bytes > 0;
+      }
+      if (!need_binding_table) {
+         if (brw->gs.base.bind_bo_offset != 0) {
+            brw->gs.base.bind_bo_offset = 0;
+            brw->state.dirty.brw |= BRW_NEW_GS_BINDING_TABLE;
+         }
+         return;
+      }
+
+      /* Might want to calculate nr_surfaces first, to avoid taking up so much
+       * space for the binding table.
+       */
       bind = brw_state_batch(brw, AUB_TRACE_BINDING_TABLE,
-                             sizeof(uint32_t) * BRW_MAX_GEN6_GS_SURFACES,
-                             32, &brw->ff_gs.bind_bo_offset);
+                             sizeof(uint32_t) * BRW_MAX_SURFACES,
+                             32, &brw->gs.base.bind_bo_offset);
 
       /* BRW_NEW_SURFACES */
-      memcpy(bind, brw->ff_gs.surf_offset, BRW_MAX_GEN6_GS_SURFACES * sizeof(uint32_t));
+      memcpy(bind, brw->gs.base.surf_offset,
+             BRW_MAX_SURFACES * sizeof(uint32_t));
    }
 
    brw->state.dirty.brw |= BRW_NEW_GS_BINDING_TABLE;