[Mesa-dev] [PATCH v4 08/12] i965: Add CS push constant info to brw_cs_prog_data

[Jordan Justen]

We need information about push constants in a few places for the GL
driver, and another couple places for the vulkan driver.

When we add support for uploading both a common (cross-thread) set of
push constants, combined with the previous per-thread push constant
data, things are going to get even more complicated. To simplify
things, we add push constant info into the cs prog_data struct.

The cross-thread constant support is added as of Haswell. To support
it we need to make sure all push constants with uniform values are
added to earlier registers. The register that varies per thread and
holds the thread invocation's unique local ID needs to be added last.

For now we add the code that would calculate cross-thread constatn
information for hsw+, but we force it (cross_thread_supported) off
until the other parts of the driver support it.

v4:
 * Support older local ID push constant layout as well. (Jason)

Signed-off-by: Jordan Justen <jordan.l.justen at intel.com>
---
 src/mesa/drivers/dri/i965/brw_compiler.h | 12 +++++++
 src/mesa/drivers/dri/i965/brw_fs.cpp     | 61 ++++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/brw_compiler.h b/src/mesa/drivers/dri/i965/brw_compiler.h
index f1f9e56..dda6297 100644
--- a/src/mesa/drivers/dri/i965/brw_compiler.h
+++ b/src/mesa/drivers/dri/i965/brw_compiler.h
@@ -424,6 +424,12 @@ struct brw_wm_prog_data {
    int urb_setup[VARYING_SLOT_MAX];
 };
 
+struct brw_push_const_block {
+   unsigned dwords;     /* Dword count, not reg aligned */
+   unsigned regs;
+   unsigned size;       /* Bytes, register aligned */
+};
+
 struct brw_cs_prog_data {
    struct brw_stage_prog_data base;
 
@@ -437,6 +443,12 @@ struct brw_cs_prog_data {
    int thread_local_id_index;
 
    struct {
+      struct brw_push_const_block cross_thread;
+      struct brw_push_const_block per_thread;
+      struct brw_push_const_block total;
+   } push;
+
+   struct {
       /** @{
        * surface indices the CS-specific surfaces
        */
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 7e5d583..d461e2f 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -6562,6 +6562,64 @@ fs_visitor::emit_cs_work_group_id_setup()
 }
 
 static void
+fill_push_const_block_info(struct brw_push_const_block *block, unsigned dwords)
+{
+   block->dwords = dwords;
+   block->regs = DIV_ROUND_UP(dwords, 8);
+   block->size = block->regs * 32;
+}
+
+static void
+cs_fill_push_const_info(const struct brw_device_info *devinfo,
+                        struct brw_cs_prog_data *cs_prog_data)
+{
+   const struct brw_stage_prog_data *prog_data =
+      (struct brw_stage_prog_data*) cs_prog_data;
+   bool fill_thread_id =
+      cs_prog_data->thread_local_id_index >= 0 &&
+      cs_prog_data->thread_local_id_index < (int)prog_data->nr_params;
+   bool cross_thread_supported = false; /* Not yet supported by driver. */
+
+   /* The thread ID should be stored in the last param dword */
+   assert(prog_data->nr_params > 0 || !fill_thread_id);
+   assert(!fill_thread_id ||
+          cs_prog_data->thread_local_id_index ==
+             (int)prog_data->nr_params - 1);
+
+   unsigned cross_thread_dwords, per_thread_dwords;
+   if (!cross_thread_supported) {
+      cross_thread_dwords = 0u;
+      per_thread_dwords =
+         8 * cs_prog_data->local_invocation_id_regs +
+         prog_data->nr_params;
+   } else if (fill_thread_id) {
+      /* Fill all but the last register with cross-thread payload */
+      cross_thread_dwords = 8 * (cs_prog_data->thread_local_id_index / 8);
+      per_thread_dwords = prog_data->nr_params - cross_thread_dwords;
+      assert(per_thread_dwords > 0 && per_thread_dwords <= 8);
+   } else {
+      /* Fill all data using cross-thread payload */
+      cross_thread_dwords = prog_data->nr_params;
+      per_thread_dwords = 0u;
+   }
+
+   fill_push_const_block_info(&cs_prog_data->push.cross_thread, cross_thread_dwords);
+   fill_push_const_block_info(&cs_prog_data->push.per_thread, per_thread_dwords);
+
+   unsigned total_dwords =
+      (cs_prog_data->push.per_thread.size * cs_prog_data->threads +
+       cs_prog_data->push.cross_thread.size) / 4;
+   fill_push_const_block_info(&cs_prog_data->push.total, total_dwords);
+
+   assert(cs_prog_data->push.cross_thread.dwords % 8 == 0 ||
+          cs_prog_data->push.per_thread.size == 0);
+   assert(cs_prog_data->push.cross_thread.dwords +
+          cs_prog_data->push.per_thread.dwords ==
+             8 * cs_prog_data->local_invocation_id_regs +
+             prog_data->nr_params);
+}
+
+static void
 cs_set_simd_size(struct brw_cs_prog_data *cs_prog_data, unsigned size)
 {
    cs_prog_data->simd_size = size;
@@ -6627,6 +6685,7 @@ brw_compile_cs(const struct brw_compiler *compiler, void *log_data,
       } else {
          cfg = v8.cfg;
          cs_set_simd_size(prog_data, 8);
+         cs_fill_push_const_info(compiler->devinfo, prog_data);
          prog_data->base.dispatch_grf_start_reg = v8.payload.num_regs;
       }
    }
@@ -6652,6 +6711,7 @@ brw_compile_cs(const struct brw_compiler *compiler, void *log_data,
       } else {
          cfg = v16.cfg;
          cs_set_simd_size(prog_data, 16);
+         cs_fill_push_const_info(compiler->devinfo, prog_data);
          prog_data->dispatch_grf_start_reg_16 = v16.payload.num_regs;
       }
    }
@@ -6679,6 +6739,7 @@ brw_compile_cs(const struct brw_compiler *compiler, void *log_data,
       } else {
          cfg = v32.cfg;
          cs_set_simd_size(prog_data, 32);
+         cs_fill_push_const_info(compiler->devinfo, prog_data);
       }
    }
 
-- 
2.8.1