From 21148e1c0a3cf9cf25ded006a3d5ce2b12803ea9 Mon Sep 17 00:00:00 2001
From: Eric Anholt <eric@anholt.net>
Date: Wed, 29 Sep 2010 10:43:46 -0700
Subject: [PATCH] i965: Clean up the virtual GRF handling.

Now, virtual GRFs are consecutive integers, rather than offsetting the
next one by the size.  We need the size information to still be around
for real register allocation, anyway.
---
 src/mesa/drivers/dri/i965/brw_fs.cpp | 76 +++++++++++++++++++---------
 1 file changed, 53 insertions(+), 23 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 7dde020e36c..e91351cb6cc 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -276,9 +276,9 @@ public:
 
    /** Register file: ARF, GRF, MRF, IMM. */
    enum register_file file;
-   /** Abstract register number.  0 = fixed hw reg */
+   /** virtual register number.  0 = fixed hw reg */
    int reg;
-   /** Offset within the abstract register. */
+   /** Offset within the virtual register. */
    int reg_offset;
    /** HW register number.  Generally unset until register allocation. */
    int hw_reg;
@@ -399,7 +399,6 @@ public:
       this->mem_ctx = talloc_new(NULL);
       this->shader = shader;
       this->fail = false;
-      this->next_abstract_grf = 1;
       this->variable_ht = hash_table_ctor(0,
 					  hash_table_pointer_hash,
 					  hash_table_pointer_compare);
@@ -413,6 +412,10 @@ public:
       this->annotation_string = NULL;
       this->annotation_ir = NULL;
       this->base_ir = NULL;
+
+      this->virtual_grf_sizes = NULL;
+      this->virtual_grf_next = 1;
+      this->virtual_grf_array_size = 0;
    }
    ~fs_visitor()
    {
@@ -421,6 +424,7 @@ public:
    }
 
    fs_reg *variable_storage(ir_variable *var);
+   int virtual_grf_alloc(int size);
 
    void visit(ir_variable *ir);
    void visit(ir_assignment *ir);
@@ -473,7 +477,11 @@ public:
    struct brw_shader *shader;
    void *mem_ctx;
    exec_list instructions;
-   int next_abstract_grf;
+
+   int *virtual_grf_sizes;
+   int virtual_grf_next;
+   int virtual_grf_array_size;
+
    struct hash_table *variable_ht;
    ir_variable *frag_color, *frag_data, *frag_depth;
    int first_non_payload_grf;
@@ -501,6 +509,24 @@ public:
 
 };
 
+int
+fs_visitor::virtual_grf_alloc(int size)
+{
+   if (virtual_grf_array_size <= virtual_grf_next) {
+      if (virtual_grf_array_size == 0)
+	 virtual_grf_array_size = 16;
+      else
+	 virtual_grf_array_size *= 2;
+      virtual_grf_sizes = talloc_realloc(mem_ctx, virtual_grf_sizes,
+					 int, virtual_grf_array_size);
+
+      /* This slot is always unused. */
+      virtual_grf_sizes[0] = 0;
+   }
+   virtual_grf_sizes[virtual_grf_next] = size;
+   return virtual_grf_next++;
+}
+
 /** Fixed HW reg constructor. */
 fs_reg::fs_reg(enum register_file file, int hw_reg)
 {
@@ -540,9 +566,8 @@ fs_reg::fs_reg(class fs_visitor *v, const struct glsl_type *type)
    init();
 
    this->file = GRF;
-   this->reg = v->next_abstract_grf;
+   this->reg = v->virtual_grf_alloc(type_size(type));
    this->reg_offset = 0;
-   v->next_abstract_grf += type_size(type);
    this->type = brw_type_for_base_type(type);
 }
 
@@ -1898,15 +1923,6 @@ fs_visitor::generate_discard(fs_inst *inst, struct brw_reg temp)
    brw_pop_insn_state(p);
 }
 
-static void
-trivial_assign_reg(int header_size, fs_reg *reg)
-{
-   if (reg->file == GRF && reg->reg != 0) {
-      reg->hw_reg = header_size + reg->reg - 1 + reg->reg_offset;
-      reg->reg = 0;
-   }
-}
-
 void
 fs_visitor::assign_curb_setup()
 {
@@ -1980,23 +1996,37 @@ fs_visitor::assign_urb_setup()
    this->first_non_payload_grf = urb_start + c->prog_data.urb_read_length;
 }
 
+static void
+trivial_assign_reg(int *reg_hw_locations, fs_reg *reg)
+{
+   if (reg->file == GRF && reg->reg != 0) {
+      reg->hw_reg = reg_hw_locations[reg->reg] + reg->reg_offset;
+      reg->reg = 0;
+   }
+}
+
 void
 fs_visitor::assign_regs()
 {
-   int header_size = this->first_non_payload_grf;
    int last_grf = 0;
+   int hw_reg_mapping[this->virtual_grf_next];
+   int i;
+
+   hw_reg_mapping[0] = 0;
+   hw_reg_mapping[1] = this->first_non_payload_grf;
+   for (i = 2; i < this->virtual_grf_next; i++) {
+      hw_reg_mapping[i] = (hw_reg_mapping[i - 1] +
+			   this->virtual_grf_sizes[i - 1]);
+   }
+   last_grf = hw_reg_mapping[i - 1] + this->virtual_grf_sizes[i - 1];
 
    /* FINISHME: trivial assignment of register numbers */
    foreach_iter(exec_list_iterator, iter, this->instructions) {
       fs_inst *inst = (fs_inst *)iter.get();
 
-      trivial_assign_reg(header_size, &inst->dst);
-      trivial_assign_reg(header_size, &inst->src[0]);
-      trivial_assign_reg(header_size, &inst->src[1]);
-
-      last_grf = MAX2(last_grf, inst->dst.hw_reg);
-      last_grf = MAX2(last_grf, inst->src[0].hw_reg);
-      last_grf = MAX2(last_grf, inst->src[1].hw_reg);
+      trivial_assign_reg(hw_reg_mapping, &inst->dst);
+      trivial_assign_reg(hw_reg_mapping, &inst->src[0]);
+      trivial_assign_reg(hw_reg_mapping, &inst->src[1]);
    }
 
    this->grf_used = last_grf + 1;