libX11 libXext mesa pixman xserver xkeyboard-config git update 26 July 2011

1 files changed, 231 insertions, 78 deletions

diff --git a/mesalib/src/glsl/lower_variable_index_to_cond_assign.cpp b/mesalib/src/glsl/lower_variable_index_to_cond_assign.cpp
index 8eb1612f0..f8e4a1de4 100644
--- a/mesalib/src/glsl/lower_variable_index_to_cond_assign.cpp
+++ b/mesalib/src/glsl/lower_variable_index_to_cond_assign.cpp
@@ -29,6 +29,21 @@
  *
  * Pre-DX10 GPUs often don't have a native way to do this operation,
  * and this works around that.
+ *
+ * The lowering process proceeds as follows.  Each non-constant index
+ * found in an r-value is converted to a canonical form \c array[i].  Each
+ * element of the array is conditionally assigned to a temporary by comparing
+ * \c i to a constant index.  This is done by cloning the canonical form and
+ * replacing all occurances of \c i with a constant.  Each remaining occurance
+ * of the canonical form in the IR is replaced with a dereference of the
+ * temporary variable.
+ *
+ * L-values with non-constant indices are handled similarly.  In this case,
+ * the RHS of the assignment is assigned to a temporary.  The non-constant
+ * index is replace with the canonical form (just like for r-values).  The
+ * temporary is conditionally assigned to each element of the canonical form
+ * by comparing \c i with each index.  The same clone-and-replace scheme is
+ * used.
  */
 
 #include "ir.h"
@@ -37,10 +52,140 @@
 #include "glsl_types.h"
 #include "main/macros.h"
 
+/**
+ * Generate a comparison value for a block of indices
+ *
+ * Lowering passes for non-constant indexing of arrays, matrices, or vectors
+ * can use this to generate blocks of index comparison values.
+ *
+ * \param instructions  List where new instructions will be appended
+ * \param index         \c ir_variable containing the desired index
+ * \param base          Base value for this block of comparisons
+ * \param components    Number of unique index values to compare.  This must
+ *                      be on the range [1, 4].
+ * \param mem_ctx       ralloc memory context to be used for all allocations.
+ *
+ * \returns
+ * An \c ir_rvalue that \b must be cloned for each use in conditional
+ * assignments, etc.
+ */
+ir_rvalue *
+compare_index_block(exec_list *instructions, ir_variable *index,
+		    unsigned base, unsigned components, void *mem_ctx)
+{
+   ir_rvalue *broadcast_index = new(mem_ctx) ir_dereference_variable(index);
+
+   assert(index->type->is_scalar());
+   assert(index->type->base_type == GLSL_TYPE_INT);
+   assert(components >= 1 && components <= 4);
+
+   if (components > 1) {
+      const ir_swizzle_mask m = { 0, 0, 0, 0, components, false };
+      broadcast_index = new(mem_ctx) ir_swizzle(broadcast_index, m);
+   }
+
+   /* Compare the desired index value with the next block of four indices.
+    */
+   ir_constant_data test_indices_data;
+   memset(&test_indices_data, 0, sizeof(test_indices_data));
+   test_indices_data.i[0] = base;
+   test_indices_data.i[1] = base + 1;
+   test_indices_data.i[2] = base + 2;
+   test_indices_data.i[3] = base + 3;
+
+   ir_constant *const test_indices =
+      new(mem_ctx) ir_constant(broadcast_index->type,
+			       &test_indices_data);
+
+   ir_rvalue *const condition_val =
+      new(mem_ctx) ir_expression(ir_binop_equal,
+				 &glsl_type::bool_type[components - 1],
+				 broadcast_index,
+				 test_indices);
+
+   ir_variable *const condition =
+      new(mem_ctx) ir_variable(condition_val->type,
+			       "dereference_condition",
+			       ir_var_temporary);
+   instructions->push_tail(condition);
+
+   ir_rvalue *const cond_deref =
+      new(mem_ctx) ir_dereference_variable(condition);
+   instructions->push_tail(new(mem_ctx) ir_assignment(cond_deref, condition_val, 0));
+
+   return cond_deref;
+}
+
+static inline bool
+is_array_or_matrix(const ir_instruction *ir)
+{
+   return (ir->type->is_array() || ir->type->is_matrix());
+}
+
+/**
+ * Replace a dereference of a variable with a specified r-value
+ *
+ * Each time a dereference of the specified value is replaced, the r-value
+ * tree is cloned.
+ */
+class deref_replacer : public ir_rvalue_visitor {
+public:
+   deref_replacer(const ir_variable *variable_to_replace, ir_rvalue *value)
+      : variable_to_replace(variable_to_replace), value(value),
+	progress(false)
+   {
+      assert(this->variable_to_replace != NULL);
+      assert(this->value != NULL);
+   }
+
+   virtual void handle_rvalue(ir_rvalue **rvalue)
+   {
+      ir_dereference_variable *const dv = (*rvalue)->as_dereference_variable();
+
+      if ((dv != NULL) && (dv->var == this->variable_to_replace)) {
+	 this->progress = true;
+	 *rvalue = this->value->clone(ralloc_parent(*rvalue), NULL);
+      }
+   }
+
+   const ir_variable *variable_to_replace;
+   ir_rvalue *value;
+   bool progress;
+};
+
+/**
+ * Find a variable index dereference of an array in an rvalue tree
+ */
+class find_variable_index : public ir_hierarchical_visitor {
+public:
+   find_variable_index()
+      : deref(NULL)
+   {
+      /* empty */
+   }
+
+   virtual ir_visitor_status visit_enter(ir_dereference_array *ir)
+   {
+      if (is_array_or_matrix(ir->array)
+	  && (ir->array_index->as_constant() == NULL)) {
+	 this->deref = ir;
+	 return visit_stop;
+      }
+
+      return visit_continue;
+   }
+
+   /**
+    * First array dereference found in the tree that has a non-constant index.
+    */
+   ir_dereference_array *deref;
+};
+
 struct assignment_generator
 {
    ir_instruction* base_ir;
-   ir_rvalue* array;
+   ir_dereference *rvalue;
+   ir_variable *old_index;
    bool is_write;
    unsigned int write_mask;
    ir_variable* var;
@@ -55,18 +200,23 @@ struct assignment_generator
        * underlying variable.
        */
       void *mem_ctx = ralloc_parent(base_ir);
-      ir_dereference *element =
-	 new(mem_ctx) ir_dereference_array(this->array->clone(mem_ctx, NULL),
-					   new(mem_ctx) ir_constant(i));
-      ir_rvalue *variable = new(mem_ctx) ir_dereference_variable(this->var);
 
-      ir_assignment *assignment;
-      if (is_write) {
-	 assignment = new(mem_ctx) ir_assignment(element, variable, condition,
-						 write_mask);
-      } else {
-	 assignment = new(mem_ctx) ir_assignment(variable, element, condition);
-      }
+      /* Clone the old r-value in its entirety.  Then replace any occurances of
+       * the old variable index with the new constant index.
+       */
+      ir_dereference *element = this->rvalue->clone(mem_ctx, NULL);
+      ir_constant *const index = new(mem_ctx) ir_constant(i);
+      deref_replacer r(this->old_index, index);
+      element->accept(&r);
+      assert(r.progress);
+
+      /* Generate a conditional assignment to (or from) the constant indexed
+       * array dereference.
+       */
+      ir_rvalue *variable = new(mem_ctx) ir_dereference_variable(this->var);
+      ir_assignment *const assignment = (is_write)
+	 ? new(mem_ctx) ir_assignment(element, variable, condition, write_mask)
+	 : new(mem_ctx) ir_assignment(variable, element, condition);
 
       list->push_tail(assignment);
    }
@@ -118,54 +268,17 @@ struct switch_generator
       for (unsigned i = first; i < end; i += 4) {
          const unsigned comps = MIN2(condition_components, end - i);
 
-         ir_rvalue *broadcast_index =
-	    new(this->mem_ctx) ir_dereference_variable(index);
-
-         if (comps) {
-	    const ir_swizzle_mask m = { 0, 0, 0, 0, comps, false };
-	    broadcast_index = new(this->mem_ctx) ir_swizzle(broadcast_index, m);
-	 }
-
-	 /* Compare the desired index value with the next block of four indices.
-	  */
-         ir_constant_data test_indices_data;
-         memset(&test_indices_data, 0, sizeof(test_indices_data));
-         test_indices_data.i[0] = i;
-         test_indices_data.i[1] = i + 1;
-         test_indices_data.i[2] = i + 2;
-         test_indices_data.i[3] = i + 3;
-         ir_constant *const test_indices =
-	    new(this->mem_ctx) ir_constant(broadcast_index->type,
-					   &test_indices_data);
-
-         ir_rvalue *const condition_val =
-	    new(this->mem_ctx) ir_expression(ir_binop_equal,
-					     &glsl_type::bool_type[comps - 1],
-					     broadcast_index,
-					     test_indices);
-
-         ir_variable *const condition =
-	    new(this->mem_ctx) ir_variable(condition_val->type,
-					   "dereference_array_condition",
-					   ir_var_temporary);
-         list->push_tail(condition);
-
 	 ir_rvalue *const cond_deref =
-	    new(this->mem_ctx) ir_dereference_variable(condition);
-         list->push_tail(new(this->mem_ctx) ir_assignment(cond_deref,
-							  condition_val, 0));
+	    compare_index_block(list, index, i, comps, this->mem_ctx);
 
          if (comps == 1) {
-	    ir_rvalue *const cond_deref =
-	       new(this->mem_ctx) ir_dereference_variable(condition);
-
-            this->generator.generate(i, cond_deref, list);
+            this->generator.generate(i, cond_deref->clone(this->mem_ctx, NULL),
+				     list);
          } else {
             for (unsigned j = 0; j < comps; j++) {
-	       ir_rvalue *const cond_deref =
-		  new(this->mem_ctx) ir_dereference_variable(condition);
 	       ir_rvalue *const cond_swiz =
-		  new(this->mem_ctx) ir_swizzle(cond_deref, j, 0, 0, 0, 1);
+		  new(this->mem_ctx) ir_swizzle(cond_deref->clone(this->mem_ctx, NULL),
+						j, 0, 0, 0, 1);
 
                this->generator.generate(i + j, cond_swiz, list);
             }
@@ -233,21 +346,18 @@ public:
    bool lower_temps;
    bool lower_uniforms;
 
-   bool is_array_or_matrix(const ir_instruction *ir) const
-   {
-      return (ir->type->is_array() || ir->type->is_matrix());
-   }
-
-   bool needs_lowering(ir_dereference_array *deref) const
+   bool storage_type_needs_lowering(ir_dereference_array *deref) const
    {
-      if (deref == NULL || deref->array_index->as_constant()
-	  || !is_array_or_matrix(deref->array))
-	 return false;
-
-      if (deref->array->ir_type == ir_type_constant)
+      /* If a variable isn't eventually the target of this dereference, then
+       * it must be a constant or some sort of anonymous temporary storage.
+       *
+       * FINISHME: Is this correct?  Most drivers treat arrays of constants as
+       * FINISHME: uniforms.  It seems like this should do the same.
+       */
+      const ir_variable *const var = deref->array->variable_referenced();
+      if (var == NULL)
 	 return this->lower_temps;
 
-      const ir_variable *const var = deref->array->variable_referenced();
       switch (var->mode) {
       case ir_var_auto:
       case ir_var_temporary:
@@ -267,8 +377,18 @@ public:
       return false;
    }
 
+   bool needs_lowering(ir_dereference_array *deref) const
+   {
+      if (deref == NULL || deref->array_index->as_constant()
+	  || !is_array_or_matrix(deref->array))
+	 return false;
+
+      return this->storage_type_needs_lowering(deref);
+   }
+
    ir_variable *convert_dereference_array(ir_dereference_array *orig_deref,
-					  ir_assignment* orig_assign)
+					  ir_assignment* orig_assign,
+					  ir_dereference *orig_base)
    {
       assert(is_array_or_matrix(orig_deref->array));
 
@@ -314,9 +434,12 @@ public:
 	 new(mem_ctx) ir_assignment(lhs, orig_deref->array_index, NULL);
       base_ir->insert_before(assign);
 
+      orig_deref->array_index = lhs->clone(mem_ctx, NULL);
+
       assignment_generator ag;
-      ag.array = orig_deref->array;
+      ag.rvalue = orig_base;
       ag.base_ir = base_ir;
+      ag.old_index = index;
       ag.var = var;
       if (orig_assign) {
 	 ag.is_write = true;
@@ -327,21 +450,40 @@ public:
 
       switch_generator sg(ag, index, 4, 4);
 
-      exec_list list;
-      sg.generate(0, length, &list);
-      base_ir->insert_before(&list);
+      /* If the original assignment has a condition, respect that original
+       * condition!  This is acomplished by wrapping the new conditional
+       * assignments in an if-statement that uses the original condition.
+       */
+      if ((orig_assign != NULL) && (orig_assign->condition != NULL)) {
+	 /* No need to clone the condition because the IR that it hangs on is
+	  * going to be removed from the instruction sequence.
+	  */
+	 ir_if *if_stmt = new(mem_ctx) ir_if(orig_assign->condition);
+
+	 sg.generate(0, length, &if_stmt->then_instructions);
+	 base_ir->insert_before(if_stmt);
+      } else {
+	 exec_list list;
+
+	 sg.generate(0, length, &list);
+	 base_ir->insert_before(&list);
+      }
 
       return var;
    }
 
    virtual void handle_rvalue(ir_rvalue **pir)
    {
+      if (this->in_assignee)
+	 return;
+
       if (!*pir)
          return;
 
       ir_dereference_array* orig_deref = (*pir)->as_dereference_array();
       if (needs_lowering(orig_deref)) {
-         ir_variable* var = convert_dereference_array(orig_deref, 0);
+         ir_variable *var =
+	    convert_dereference_array(orig_deref, NULL, orig_deref);
          assert(var);
          *pir = new(ralloc_parent(base_ir)) ir_dereference_variable(var);
          this->progress = true;
@@ -353,10 +495,11 @@ public:
    {
       ir_rvalue_visitor::visit_leave(ir);
 
-      ir_dereference_array *orig_deref = ir->lhs->as_dereference_array();
+      find_variable_index f;
+      ir->lhs->accept(&f);
 
-      if (needs_lowering(orig_deref)) {
-         convert_dereference_array(orig_deref, ir);
+      if ((f.deref != NULL) && storage_type_needs_lowering(f.deref)) {
+         convert_dereference_array(f.deref, ir, ir->lhs);
          ir->remove();
          this->progress = true;
       }
@@ -377,7 +520,17 @@ lower_variable_index_to_cond_assign(exec_list *instructions,
 					   lower_temp,
 					   lower_uniform);
 
-   visit_list_elements(&v, instructions);
-
-   return v.progress;
+   /* Continue lowering until no progress is made.  If there are multiple
+    * levels of indirection (e.g., non-constant indexing of array elements and
+    * matrix columns of an array of matrix), each pass will only lower one
+    * level of indirection.
+    */
+   bool progress_ever = false;
+   do {
+      v.progress = false;
+      visit_list_elements(&v, instructions);
+      progress_ever = v.progress || progress_ever;
+   } while (v.progress);
+
+   return progress_ever;
 }