i965: Factor out virtual GRF allocation to a separate object.

Right now virtual GRF book-keeping and allocation is performed in each
visitor class separately (among other hundred different things),
leading to duplicated logic in each visitor and preventing layering as
it forces any code that manipulates i965 IR and needs to allocate
virtual registers to depend on the specific visitor that happens to be
used to translate from GLSL IR.

v2: Use realloc()/free() to allocate VGRF book-keeping arrays (Connor).

Reviewed-by: Matt Turner <mattst88@gmail.com>

1 files changed, 21 insertions, 22 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp b/src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp
index e8e2185..b944d45 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp
@@ -45,15 +45,14 @@ assign(unsigned int *reg_hw_locations, backend_reg *reg)
 bool
 vec4_visitor::reg_allocate_trivial()
 {
-   unsigned int hw_reg_mapping[this->virtual_grf_count];
-   bool virtual_grf_used[this->virtual_grf_count];
-   int i;
+   unsigned int hw_reg_mapping[this->alloc.count];
+   bool virtual_grf_used[this->alloc.count];
    int next;
 
    /* Calculate which virtual GRFs are actually in use after whatever
     * optimization passes have occurred.
     */
-   for (int i = 0; i < this->virtual_grf_count; i++) {
+   for (unsigned i = 0; i < this->alloc.count; i++) {
       virtual_grf_used[i] = false;
    }
 
@@ -61,18 +60,18 @@ vec4_visitor::reg_allocate_trivial()
       if (inst->dst.file == GRF)
 	 virtual_grf_used[inst->dst.reg] = true;
 
-      for (int i = 0; i < 3; i++) {
+      for (unsigned i = 0; i < 3; i++) {
 	 if (inst->src[i].file == GRF)
 	    virtual_grf_used[inst->src[i].reg] = true;
       }
    }
 
    hw_reg_mapping[0] = this->first_non_payload_grf;
-   next = hw_reg_mapping[0] + this->virtual_grf_sizes[0];
-   for (i = 1; i < this->virtual_grf_count; i++) {
+   next = hw_reg_mapping[0] + this->alloc.sizes[0];
+   for (unsigned i = 1; i < this->alloc.count; i++) {
       if (virtual_grf_used[i]) {
 	 hw_reg_mapping[i] = next;
-	 next += this->virtual_grf_sizes[i];
+	 next += this->alloc.sizes[i];
       }
    }
    prog_data->total_grf = next;
@@ -176,7 +175,7 @@ bool
 vec4_visitor::reg_allocate()
 {
    struct intel_screen *screen = brw->intelScreen;
-   unsigned int hw_reg_mapping[virtual_grf_count];
+   unsigned int hw_reg_mapping[alloc.count];
    int payload_reg_count = this->first_non_payload_grf;
 
    /* Using the trivial allocator can be useful in debugging undefined
@@ -187,19 +186,19 @@ vec4_visitor::reg_allocate()
 
    calculate_live_intervals();
 
-   int node_count = virtual_grf_count;
+   int node_count = alloc.count;
    int first_payload_node = node_count;
    node_count += payload_reg_count;
    struct ra_graph *g =
       ra_alloc_interference_graph(screen->vec4_reg_set.regs, node_count);
 
-   for (int i = 0; i < virtual_grf_count; i++) {
-      int size = this->virtual_grf_sizes[i];
+   for (unsigned i = 0; i < alloc.count; i++) {
+      int size = this->alloc.sizes[i];
       assert(size >= 1 && size <= 2 &&
              "Register allocation relies on split_virtual_grfs().");
       ra_set_node_class(g, i, screen->vec4_reg_set.classes[size - 1]);
 
-      for (int j = 0; j < i; j++) {
+      for (unsigned j = 0; j < i; j++) {
 	 if (virtual_grf_interferes(i, j)) {
 	    ra_add_node_interference(g, i, j);
 	 }
@@ -230,12 +229,12 @@ vec4_visitor::reg_allocate()
     * numbers.
     */
    prog_data->total_grf = payload_reg_count;
-   for (int i = 0; i < virtual_grf_count; i++) {
+   for (unsigned i = 0; i < alloc.count; i++) {
       int reg = ra_get_node_reg(g, i);
 
       hw_reg_mapping[i] = screen->vec4_reg_set.ra_reg_to_grf[reg];
       prog_data->total_grf = MAX2(prog_data->total_grf,
-				  hw_reg_mapping[i] + virtual_grf_sizes[i]);
+				  hw_reg_mapping[i] + alloc.sizes[i]);
    }
 
    foreach_block_and_inst(block, vec4_instruction, inst, cfg) {
@@ -255,9 +254,9 @@ vec4_visitor::evaluate_spill_costs(float *spill_costs, bool *no_spill)
 {
    float loop_scale = 1.0;
 
-   for (int i = 0; i < this->virtual_grf_count; i++) {
+   for (unsigned i = 0; i < this->alloc.count; i++) {
       spill_costs[i] = 0.0;
-      no_spill[i] = virtual_grf_sizes[i] != 1;
+      no_spill[i] = alloc.sizes[i] != 1;
    }
 
    /* Calculate costs for spilling nodes.  Call it a cost of 1 per
@@ -308,12 +307,12 @@ vec4_visitor::evaluate_spill_costs(float *spill_costs, bool *no_spill)
 int
 vec4_visitor::choose_spill_reg(struct ra_graph *g)
 {
-   float spill_costs[this->virtual_grf_count];
-   bool no_spill[this->virtual_grf_count];
+   float spill_costs[this->alloc.count];
+   bool no_spill[this->alloc.count];
 
    evaluate_spill_costs(spill_costs, no_spill);
 
-   for (int i = 0; i < this->virtual_grf_count; i++) {
+   for (unsigned i = 0; i < this->alloc.count; i++) {
       if (!no_spill[i])
          ra_set_node_spill_cost(g, i, spill_costs[i]);
    }
@@ -324,7 +323,7 @@ vec4_visitor::choose_spill_reg(struct ra_graph *g)
 void
 vec4_visitor::spill_reg(int spill_reg_nr)
 {
-   assert(virtual_grf_sizes[spill_reg_nr] == 1);
+   assert(alloc.sizes[spill_reg_nr] == 1);
    unsigned int spill_offset = c->last_scratch++;
 
    /* Generate spill/unspill instructions for the objects being spilled. */
@@ -332,7 +331,7 @@ vec4_visitor::spill_reg(int spill_reg_nr)
       for (unsigned int i = 0; i < 3; i++) {
          if (inst->src[i].file == GRF && inst->src[i].reg == spill_reg_nr) {
             src_reg spill_reg = inst->src[i];
-            inst->src[i].reg = virtual_grf_alloc(1);
+            inst->src[i].reg = alloc.allocate(1);
             dst_reg temp = dst_reg(inst->src[i]);
 
             emit_scratch_read(block, inst, temp, spill_reg, spill_offset);