i965: Program the push constants state using the gather table

Use the gather table generated from the uniform uploads and
ir_binop_ubo_load to gather and pack the constants to the gather pool.

Note that the 3DSTATE_CONSTANT_* packet now refers to the gather
pool generated by the resource streamer instead of the constant buffer
pointed to by an offset of the dynamic state base address.

v2: Support GEN8 + non-trivial rebase.

Signed-off-by: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>

5 files changed, 79 insertions, 13 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_state.h b/src/mesa/drivers/dri/i965/brw_state.h
index c7c7e0b595..a1e6c73c33 100644
--- a/src/mesa/drivers/dri/i965/brw_state.h
+++ b/src/mesa/drivers/dri/i965/brw_state.h
@@ -361,7 +361,7 @@ brw_upload_pull_constants(struct brw_context *brw,
 void
 gen7_upload_constant_state(struct brw_context *brw,
                            const struct brw_stage_state *stage_state,
-                           bool active, unsigned opcode);
+                           bool active, unsigned opcode, unsigned gather_op);
 
 void gen7_rs_control(struct brw_context *brw, int enable);
 
diff --git a/src/mesa/drivers/dri/i965/gen6_gs_state.c b/src/mesa/drivers/dri/i965/gen6_gs_state.c
index eb4c58601f..79a899ef9a 100644
--- a/src/mesa/drivers/dri/i965/gen6_gs_state.c
+++ b/src/mesa/drivers/dri/i965/gen6_gs_state.c
@@ -48,7 +48,7 @@ gen6_upload_gs_push_constants(struct brw_context *brw)
    }
 
    if (brw->gen >= 7)
-      gen7_upload_constant_state(brw, stage_state, gp, _3DSTATE_CONSTANT_GS);
+      gen7_upload_constant_state(brw, stage_state, gp, _3DSTATE_CONSTANT_GS, _3DSTATE_GATHER_CONSTANT_GS);
 }
 
 const struct brw_tracked_state gen6_gs_push_constants = {
diff --git a/src/mesa/drivers/dri/i965/gen6_vs_state.c b/src/mesa/drivers/dri/i965/gen6_vs_state.c
index d43af5b26e..bb375b9c9d 100644
--- a/src/mesa/drivers/dri/i965/gen6_vs_state.c
+++ b/src/mesa/drivers/dri/i965/gen6_vs_state.c
@@ -174,7 +174,7 @@ gen6_upload_vs_push_constants(struct brw_context *brw)
          gen7_emit_vs_workaround_flush(brw);
 
       gen7_upload_constant_state(brw, stage_state, true /* active */,
-                                 _3DSTATE_CONSTANT_VS);
+                                 _3DSTATE_CONSTANT_VS, _3DSTATE_GATHER_CONSTANT_VS);
    }
 }
 
diff --git a/src/mesa/drivers/dri/i965/gen6_wm_state.c b/src/mesa/drivers/dri/i965/gen6_wm_state.c
index d1748ba745..c7b37c6a8c 100644
--- a/src/mesa/drivers/dri/i965/gen6_wm_state.c
+++ b/src/mesa/drivers/dri/i965/gen6_wm_state.c
@@ -51,7 +51,7 @@ gen6_upload_wm_push_constants(struct brw_context *brw)
 
    if (brw->gen >= 7) {
       gen7_upload_constant_state(brw, &brw->wm.base, true,
-                                 _3DSTATE_CONSTANT_PS);
+                                 _3DSTATE_CONSTANT_PS, _3DSTATE_GATHER_CONSTANT_PS);
    }
 }
 
diff --git a/src/mesa/drivers/dri/i965/gen7_vs_state.c b/src/mesa/drivers/dri/i965/gen7_vs_state.c
index b7e4858548..cf07658c03 100644
--- a/src/mesa/drivers/dri/i965/gen7_vs_state.c
+++ b/src/mesa/drivers/dri/i965/gen7_vs_state.c
@@ -28,19 +28,70 @@
 #include "program/prog_parameter.h"
 #include "program/prog_statevars.h"
 #include "intel_batchbuffer.h"
+#include "glsl/glsl_parser_extras.h"
 
+static void
+gen7_submit_gather_table(struct brw_context* brw,
+                         const struct brw_stage_state *stage_state,
+                         const struct brw_stage_prog_data *prog_data,
+                         unsigned gather_opcode)
+{
+   uint32_t gather_dwords = 3 + prog_data->nr_gather_table;
+
+   /* Ordinary uniforms are assigned to the first constant buffer slot */
+   unsigned cb_valid = 1;
+   /* Assign subsequent constant buffer slots to UBOs if any */
+   cb_valid |= (prog_data->nr_ubo_params > 0) ?
+      (2 << (BRW_UBO_GATHER_INDEX_APPEND + prog_data->max_ubo_const_block)) - 1 : 0;
+
+   assert(cb_valid < 0xffff);
+
+   BEGIN_BATCH(gather_dwords);
+   OUT_BATCH(gather_opcode << 16 | (gather_dwords - 2));
+   OUT_BATCH(SET_FIELD(cb_valid, BRW_GATHER_BUFFER_VALID) |
+             SET_FIELD(BRW_UNIFORM_GATHER_INDEX_START / 16,
+                       BRW_GATHER_BINDING_TABLE_BLOCK));
+   OUT_BATCH(stage_state->push_const_offset);
+   for (int i = 0; i < prog_data->nr_gather_table; i++) {
+      /* Which bo are we referring to? The uniform constant buffer or
+       * the UBO block?
+       */
+      bool is_uniform = prog_data->gather_table[i].reg == -1;
+      int cb_offset = is_uniform ? i :
+         (prog_data->gather_table[i].const_offset / 16);
+      int bt_offset = is_uniform ? 0 :
+         (prog_data->gather_table[i].const_block + BRW_UBO_GATHER_INDEX_APPEND);
+
+      assert(cb_offset < 256);
+      assert(bt_offset < 16);
+
+      OUT_BATCH(SET_FIELD(cb_offset, BRW_GATHER_CONST_BUFFER_OFFSET) |
+                SET_FIELD(prog_data->gather_table[i].channel_mask,
+                          BRW_GATHER_CHANNEL_MASK) | bt_offset);
+   }
+   ADVANCE_BATCH();
+}
 
 void
 gen7_upload_constant_state(struct brw_context *brw,
                            const struct brw_stage_state *stage_state,
-                           bool active, unsigned opcode)
+                           bool active, unsigned opcode, unsigned gather_opcode)
 {
    uint32_t mocs = brw->gen < 8 ? GEN7_MOCS_L3 : 0;
 
    /* Disable if the shader stage is inactive or there are no push constants. */
    active = active && stage_state->push_const_size != 0;
 
+   bool use_gather = (brw->gather_pool.bo != NULL);
+
+   int const_loc = use_gather ? 16 : 0;
    int dwords = brw->gen >= 8 ? 11 : 7;
+
+   struct brw_stage_prog_data *prog_data = stage_state->prog_data;
+   if (prog_data && use_gather && active) {
+      gen7_submit_gather_table(brw, stage_state, prog_data, gather_opcode);
+   }
+
    BEGIN_BATCH(dwords);
    OUT_BATCH(opcode << 16 | (dwords - 2));
 
@@ -59,10 +110,9 @@ gen7_upload_constant_state(struct brw_context *brw,
       OUT_BATCH(0);
       OUT_BATCH(stage_state->push_const_size);
    } else {
-      OUT_BATCH(active ? stage_state->push_const_size : 0);
+      OUT_BATCH(active ? stage_state->push_const_size << const_loc : 0);
       OUT_BATCH(0);
    }
-
    /* Pointer to the constant buffer.  Covered by the set of state flags
     * from gen6_prepare_wm_contants
     */
@@ -79,23 +129,39 @@ gen7_upload_constant_state(struct brw_context *brw,
       OUT_BATCH(0);
       OUT_BATCH(0);
    } else if (brw->gen>= 8) {
-      OUT_BATCH(active ? (stage_state->push_const_offset | mocs) : 0);
-      OUT_BATCH(0);
-      OUT_BATCH(0);
-      OUT_BATCH(0);
+      if (use_gather) {
+         OUT_BATCH(0);
+         OUT_BATCH(0);
+         OUT_BATCH(active ? (stage_state->push_const_offset | mocs) : 0);
+         OUT_BATCH(0);
+      } else {
+         OUT_BATCH(active ? (stage_state->push_const_offset | mocs) : 0);
+         OUT_BATCH(0);
+         OUT_BATCH(0);
+         OUT_BATCH(0);
+      }
       OUT_BATCH(0);
       OUT_BATCH(0);
       OUT_BATCH(0);
       OUT_BATCH(0);
    } else {
-      OUT_BATCH(active ? (stage_state->push_const_offset | mocs) : 0);
-      OUT_BATCH(0);
+      if (use_gather) {
+         OUT_BATCH(0);
+         OUT_BATCH(active ? (stage_state->push_const_offset | mocs) : 0);
+      } else {
+         OUT_BATCH(active ? (stage_state->push_const_offset | mocs) : 0);
+         OUT_BATCH(0);
+      }
       OUT_BATCH(0);
       OUT_BATCH(0);
    }
 
    ADVANCE_BATCH();
 
+   /* Re-enable gather again if required */
+   if (gather_switched_off)
+      gen7_toggle_gather_constants(brw, true);
+
    /* On SKL+ the new constants don't take effect until the next corresponding
     * 3DSTATE_BINDING_TABLE_POINTER_* command is parsed so we need to ensure
     * that is sent