Switch to Mesa 7.9.

media-libs/mesa/files/7.9-remove-discard-from-lower_jumps.patch

+Backport of this patch to mesa 7.9:
+
+From 1802cb9bafc4125300870be51e8b22ddd795d61e Mon Sep 17 00:00:00 2001
+From: Kenneth Graunke <kenneth@whitecape.org>
+Date: Mon, 29 Nov 2010 18:59:16 +0000
+Subject: glsl: Remove "discard" support from lower_jumps.
+
+The new lower_discard and opt_discard_simplification passes should
+handle all the necessary transformations, so lower_jumps doesn't need to
+support it.
+
+Also, lower_jumps incorrectly handled conditional discards - it would
+unconditionally truncate all code after the discard.  Rather than fixing
+the bug, simply remove the code.
+
+NOTE: This is a candidate for the 7.9 branch.
+---
+diff -Naurp Mesa-7.9.orig/src/glsl/ir_lower_jumps.cpp Mesa-7.9.work/src/glsl/ir_lower_jumps.cpp
+--- Mesa-7.9.orig/src/glsl/ir_lower_jumps.cpp   2010-12-07 18:22:17.749760000 -0800
++++ Mesa-7.9.work/src/glsl/ir_lower_jumps.cpp   2010-12-13 11:26:58.014994000 -0800
+@@ -36,7 +36,6 @@ enum jump_strength
+    strength_continue,
+    strength_break,
+    strength_return,
+-   strength_discard
+ };
+ 
+ struct block_record
+@@ -202,8 +201,6 @@ struct ir_lower_jumps_visitor : public i
+ 
+    virtual void visit(class ir_discard * ir)
+    {
+-      truncate_after_instruction(ir);
+-      this->block.min_strength = strength_discard;
+    }
+ 
+    enum jump_strength get_jump_strength(ir_instruction* ir)
+@@ -217,8 +214,6 @@ struct ir_lower_jumps_visitor : public i
+             return strength_continue;
+       } else if(ir->ir_type == ir_type_return)
+          return strength_return;
+-      else if(ir->ir_type == ir_type_discard)
+-         return strength_discard;
+       else
+          return strength_none;
+    }
+@@ -253,9 +248,6 @@ struct ir_lower_jumps_visitor : public i
+          else
+             lower = lower_sub_return;
+          break;
+-      case strength_discard:
+-         lower = false; /* probably nothing needs this lowered */
+-         break;
+       }
+       return lower;
+    }
+@@ -313,7 +305,6 @@ retry: /* we get here if we put code aft
+             /* FINISHME: unify returns with identical expressions */
+             else if(jump_strengths[0] == strength_return && this->function.signature->return_type->is_void())
+                ir->insert_after(new(ir) ir_return(NULL));
+-            /* FINISHME: unify discards */
+             else
+                unify = false;
+ 
+diff -Naurp Mesa-7.9.orig/src/glsl/ir_lower_jumps.cpp~ Mesa-7.9.work/src/glsl/ir_lower_jumps.cpp~
+--- Mesa-7.9.orig/src/glsl/ir_lower_jumps.cpp~  1969-12-31 16:00:00.000000000 -0800
++++ Mesa-7.9.work/src/glsl/ir_lower_jumps.cpp~  2010-12-13 11:26:29.542278000 -0800
+@@ -0,0 +1,539 @@
++/*
++ * Copyright © 2010 Luca Barbieri
++ *
++ * Permission is hereby granted, free of charge, to any person obtaining a
++ * copy of this software and associated documentation files (the "Software"),
++ * to deal in the Software without restriction, including without limitation
++ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
++ * and/or sell copies of the Software, and to permit persons to whom the
++ * Software is furnished to do so, subject to the following conditions:
++ *
++ * The above copyright notice and this permission notice (including the next
++ * paragraph) shall be included in all copies or substantial portions of the
++ * Software.
++ *
++ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
++ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
++ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
++ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
++ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
++ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
++ * DEALINGS IN THE SOFTWARE.
++ */
++
++/**
++ * \file ir_lower_jumps.cpp
++ */
++
++#include "glsl_types.h"
++#include <string.h>
++#include "ir.h"
++
++enum jump_strength
++{
++   strength_none,
++   strength_always_clears_execute_flag,
++   strength_continue,
++   strength_break,
++   strength_return,
++};
++
++struct block_record
++{
++   /* minimum jump strength (of lowered IR, not pre-lowering IR)
++    *
++    * If the block ends with a jump, must be the strength of the jump.
++    * Otherwise, the jump would be dead and have been deleted before)
++    *
++    * If the block doesn't end with a jump, it can be different than strength_none if all paths before it lead to some jump
++    * (e.g. an if with a return in one branch, and a break in the other, while not lowering them)
++    * Note that identical jumps are usually unified though.
++    */
++   jump_strength min_strength;
++
++   /* can anything clear the execute flag? */
++   bool may_clear_execute_flag;
++
++   block_record()
++   {
++      this->min_strength = strength_none;
++      this->may_clear_execute_flag = false;
++   }
++};
++
++struct loop_record
++{
++   ir_function_signature* signature;
++   ir_loop* loop;
++
++   /* used to avoid lowering the break used to represent lowered breaks */
++   unsigned nesting_depth;
++   bool in_if_at_the_end_of_the_loop;
++
++   bool may_set_return_flag;
++
++   ir_variable* break_flag;
++   ir_variable* execute_flag; /* cleared to emulate continue */
++
++   loop_record(ir_function_signature* p_signature = 0, ir_loop* p_loop = 0)
++   {
++      this->signature = p_signature;
++      this->loop = p_loop;
++      this->nesting_depth = 0;
++      this->in_if_at_the_end_of_the_loop = false;
++      this->may_set_return_flag = false;
++      this->break_flag = 0;
++      this->execute_flag = 0;
++   }
++
++   ir_variable* get_execute_flag()
++   {
++      /* also supported for the "function loop" */
++      if(!this->execute_flag) {
++         exec_list& list = this->loop ? this->loop->body_instructions : signature->body;
++         this->execute_flag = new(this->signature) ir_variable(glsl_type::bool_type, "execute_flag", ir_var_temporary);
++         list.push_head(new(this->signature) ir_assignment(new(this->signature) ir_dereference_variable(execute_flag), new(this->signature) ir_constant(true), 0));
++         list.push_head(this->execute_flag);
++      }
++      return this->execute_flag;
++   }
++
++   ir_variable* get_break_flag()
++   {
++      assert(this->loop);
++      if(!this->break_flag) {
++         this->break_flag = new(this->signature) ir_variable(glsl_type::bool_type, "break_flag", ir_var_temporary);
++         this->loop->insert_before(this->break_flag);
++         this->loop->insert_before(new(this->signature) ir_assignment(new(this->signature) ir_dereference_variable(break_flag), new(this->signature) ir_constant(false), 0));
++      }
++      return this->break_flag;
++   }
++};
++
++struct function_record
++{
++   ir_function_signature* signature;
++   ir_variable* return_flag; /* used to break out of all loops and then jump to the return instruction */
++   ir_variable* return_value;
++   bool is_main;
++   unsigned nesting_depth;
++
++   function_record(ir_function_signature* p_signature = 0)
++   {
++      this->signature = p_signature;
++      this->return_flag = 0;
++      this->return_value = 0;
++      this->nesting_depth = 0;
++      this->is_main = this->signature && (strcmp(this->signature->function_name(), "main") == 0);
++   }
++
++   ir_variable* get_return_flag()
++   {
++      if(!this->return_flag) {
++         this->return_flag = new(this->signature) ir_variable(glsl_type::bool_type, "return_flag", ir_var_temporary);
++         this->signature->body.push_head(new(this->signature) ir_assignment(new(this->signature) ir_dereference_variable(return_flag), new(this->signature) ir_constant(false), 0));
++         this->signature->body.push_head(this->return_flag);
++      }
++      return this->return_flag;
++   }
++
++   ir_variable* get_return_value()
++   {
++      if(!this->return_value) {
++         assert(!this->signature->return_type->is_void());
++         return_value = new(this->signature) ir_variable(this->signature->return_type, "return_value", ir_var_temporary);
++         this->signature->body.push_head(this->return_value);
++      }
++      return this->return_value;
++   }
++};
++
++struct ir_lower_jumps_visitor : public ir_control_flow_visitor {
++   bool progress;
++
++   struct function_record function;
++   struct loop_record loop;
++   struct block_record block;
++
++   bool pull_out_jumps;
++   bool lower_continue;
++   bool lower_break;
++   bool lower_sub_return;
++   bool lower_main_return;
++
++   ir_lower_jumps_visitor()
++   {
++      this->progress = false;
++   }
++
++   void truncate_after_instruction(exec_node *ir)
++   {
++      if (!ir)
++         return;
++
++      while (!ir->get_next()->is_tail_sentinel()) {
++         ((ir_instruction *)ir->get_next())->remove();
++         this->progress = true;
++      }
++   }
++
++   void move_outer_block_inside(ir_instruction *ir, exec_list *inner_block)
++   {
++      while (!ir->get_next()->is_tail_sentinel()) {
++         ir_instruction *move_ir = (ir_instruction *)ir->get_next();
++
++         move_ir->remove();
++         inner_block->push_tail(move_ir);
++      }
++   }
++
++   virtual void visit(class ir_loop_jump * ir)
++   {
++      truncate_after_instruction(ir);
++      this->block.min_strength = ir->is_break() ? strength_break : strength_continue;
++   }
++
++   virtual void visit(class ir_return * ir)
++   {
++      truncate_after_instruction(ir);
++      this->block.min_strength = strength_return;
++   }
++
++   virtual void visit(class ir_discard * ir)
++   {
++   }
++
++   enum jump_strength get_jump_strength(ir_instruction* ir)
++   {
++      if(!ir)
++         return strength_none;
++      else if(ir->ir_type == ir_type_loop_jump) {
++         if(((ir_loop_jump*)ir)->is_break())
++            return strength_break;
++         else
++            return strength_continue;
++      } else if(ir->ir_type == ir_type_return)
++         return strength_return;
++      else
++         return strength_none;
++   }
++
++   bool should_lower_jump(ir_jump* ir)
++   {
++      unsigned strength = get_jump_strength(ir);
++      bool lower;
++      switch(strength)
++      {
++      case strength_none:
++         lower = false; /* don't change this, code relies on it */
++         break;
++      case strength_continue:
++         lower = lower_continue;
++         break;
++      case strength_break:
++         assert(this->loop.loop);
++         /* never lower "canonical break" */
++         if(ir->get_next()->is_tail_sentinel() && (this->loop.nesting_depth == 0
++               || (this->loop.nesting_depth == 1 && this->loop.in_if_at_the_end_of_the_loop)))
++            lower = false;
++         else
++            lower = lower_break;
++         break;
++      case strength_return:
++         /* never lower return at the end of a this->function */
++         if(this->function.nesting_depth == 0 && ir->get_next()->is_tail_sentinel())
++            lower = false;
++         else if (this->function.is_main)
++            lower = lower_main_return;
++         else
++            lower = lower_sub_return;
++         break;
++      case strength_discard:
++         lower = false; /* probably nothing needs this lowered */
++         break;
++      }
++      return lower;
++   }
++
++   block_record visit_block(exec_list* list)
++   {
++      block_record saved_block = this->block;
++      this->block = block_record();
++      visit_exec_list(list, this);
++      block_record ret = this->block;
++      this->block = saved_block;
++      return ret;
++   }
++
++   virtual void visit(ir_if *ir)
++   {
++      if(this->loop.nesting_depth == 0 && ir->get_next()->is_tail_sentinel())
++         this->loop.in_if_at_the_end_of_the_loop = true;
++
++      ++this->function.nesting_depth;
++      ++this->loop.nesting_depth;
++
++      block_record block_records[2];
++      ir_jump* jumps[2];
++
++      block_records[0] = visit_block(&ir->then_instructions);
++      block_records[1] = visit_block(&ir->else_instructions);
++
++retry: /* we get here if we put code after the if inside a branch */
++   for(unsigned i = 0; i < 2; ++i) {
++      exec_list& list = i ? ir->else_instructions : ir->then_instructions;
++      jumps[i] = 0;
++      if(!list.is_empty() && get_jump_strength((ir_instruction*)list.get_tail()))
++         jumps[i] = (ir_jump*)list.get_tail();
++   }
++
++      for(;;) {
++         jump_strength jump_strengths[2];
++
++         for(unsigned i = 0; i < 2; ++i) {
++            if(jumps[i]) {
++               jump_strengths[i] = block_records[i].min_strength;
++               assert(jump_strengths[i] == get_jump_strength(jumps[i]));
++            } else
++               jump_strengths[i] = strength_none;
++         }
++
++         /* move both jumps out if possible */
++         if(pull_out_jumps && jump_strengths[0] == jump_strengths[1]) {
++            bool unify = true;
++            if(jump_strengths[0] == strength_continue)
++               ir->insert_after(new(ir) ir_loop_jump(ir_loop_jump::jump_continue));
++            else if(jump_strengths[0] == strength_break)
++               ir->insert_after(new(ir) ir_loop_jump(ir_loop_jump::jump_break));
++            /* FINISHME: unify returns with identical expressions */
++            else if(jump_strengths[0] == strength_return && this->function.signature->return_type->is_void())
++               ir->insert_after(new(ir) ir_return(NULL));
++            /* FINISHME: unify discards */
++            else
++               unify = false;
++
++            if(unify) {
++               jumps[0]->remove();
++               jumps[1]->remove();
++               this->progress = true;
++
++               jumps[0] = 0;
++               jumps[1] = 0;
++               block_records[0].min_strength = strength_none;
++               block_records[1].min_strength = strength_none;
++               break;
++            }
++         }
++
++         /* lower a jump: if both need to lowered, start with the strongest one, so that
++          * we might later unify the lowered version with the other one
++          */
++         bool should_lower[2];
++         for(unsigned i = 0; i < 2; ++i)
++            should_lower[i] = should_lower_jump(jumps[i]);
++
++         int lower;
++         if(should_lower[1] && should_lower[0])
++            lower = jump_strengths[1] > jump_strengths[0];
++         else if(should_lower[0])
++            lower = 0;
++         else if(should_lower[1])
++            lower = 1;
++         else
++            break;
++
++         if(jump_strengths[lower] == strength_return) {
++            ir_variable* return_flag = this->function.get_return_flag();
++            if(!this->function.signature->return_type->is_void()) {
++               ir_variable* return_value = this->function.get_return_value();
++               jumps[lower]->insert_before(new(ir) ir_assignment(new (ir) ir_dereference_variable(return_value), ((ir_return*)jumps[lower])->value, NULL));
++            }
++            jumps[lower]->insert_before(new(ir) ir_assignment(new (ir) ir_dereference_variable(return_flag), new (ir) ir_constant(true), NULL));
++            this->loop.may_set_return_flag = true;
++            if(this->loop.loop) {
++               ir_loop_jump* lowered = 0;
++               lowered = new(ir) ir_loop_jump(ir_loop_jump::jump_break);
++               block_records[lower].min_strength = strength_break;
++               jumps[lower]->replace_with(lowered);
++               jumps[lower] = lowered;
++            } else
++               goto lower_continue;
++            this->progress = true;
++         } else if(jump_strengths[lower] == strength_break) {
++            /* We can't lower to an actual continue because that would execute the increment.
++             *
++             * In the lowered code, we instead put the break check between the this->loop body and the increment,
++             * which is impossible with a real continue as defined by the GLSL IR currently.
++             *
++             * Smarter options (such as undoing the increment) are possible but it's not worth implementing them,
++             * because if break is lowered, continue is almost surely lowered too.
++             */
++            jumps[lower]->insert_before(new(ir) ir_assignment(new (ir) ir_dereference_variable(this->loop.get_break_flag()), new (ir) ir_constant(true), 0));
++            goto lower_continue;
++         } else if(jump_strengths[lower] == strength_continue) {
++lower_continue:
++            ir_variable* execute_flag = this->loop.get_execute_flag();
++            jumps[lower]->replace_with(new(ir) ir_assignment(new (ir) ir_dereference_variable(execute_flag), new (ir) ir_constant(false), 0));
++            jumps[lower] = 0;
++            block_records[lower].min_strength = strength_always_clears_execute_flag;
++            block_records[lower].may_clear_execute_flag = true;
++            this->progress = true;
++            break;
++         }
++      }
++
++      /* move out a jump out if possible */
++      if(pull_out_jumps) {
++         int move_out = -1;
++         if(jumps[0] && block_records[1].min_strength >= strength_continue)
++            move_out = 0;
++         else if(jumps[1] && block_records[0].min_strength >= strength_continue)
++            move_out = 1;
++
++         if(move_out >= 0)
++         {
++            jumps[move_out]->remove();
++            ir->insert_after(jumps[move_out]);
++            jumps[move_out] = 0;
++            block_records[move_out].min_strength = strength_none;
++            this->progress = true;
++         }
++      }
++
++      if(block_records[0].min_strength < block_records[1].min_strength)
++         this->block.min_strength = block_records[0].min_strength;
++      else
++         this->block.min_strength = block_records[1].min_strength;
++      this->block.may_clear_execute_flag = this->block.may_clear_execute_flag || block_records[0].may_clear_execute_flag || block_records[1].may_clear_execute_flag;
++
++      if(this->block.min_strength)
++         truncate_after_instruction(ir);
++      else if(this->block.may_clear_execute_flag)
++      {
++         int move_into = -1;
++         if(block_records[0].min_strength && !block_records[1].may_clear_execute_flag)
++            move_into = 1;
++         else if(block_records[1].min_strength && !block_records[0].may_clear_execute_flag)
++            move_into = 0;
++
++         if(move_into >= 0) {
++            assert(!block_records[move_into].min_strength && !block_records[move_into].may_clear_execute_flag); /* otherwise, we just truncated */
++
++            exec_list* list = move_into ? &ir->else_instructions : &ir->then_instructions;
++            exec_node* next = ir->get_next();
++            if(!next->is_tail_sentinel()) {
++               move_outer_block_inside(ir, list);
++
++               exec_list list;
++               list.head = next;
++               block_records[move_into] = visit_block(&list);
++
++               this->progress = true;
++               goto retry;
++            }
++         } else {
++            ir_instruction* ir_after;
++            for(ir_after = (ir_instruction*)ir->get_next(); !ir_after->is_tail_sentinel();)
++            {
++               ir_if* ir_if = ir_after->as_if();
++               if(ir_if && ir_if->else_instructions.is_empty()) {
++                  ir_dereference_variable* ir_if_cond_deref = ir_if->condition->as_dereference_variable();
++                  if(ir_if_cond_deref && ir_if_cond_deref->var == this->loop.execute_flag) {
++                     ir_instruction* ir_next = (ir_instruction*)ir_after->get_next();
++                     ir_after->insert_before(&ir_if->then_instructions);
++                     ir_after->remove();
++                     ir_after = ir_next;
++                     continue;
++                  }
++               }
++               ir_after = (ir_instruction*)ir_after->get_next();
++
++               /* only set this if we find any unprotected instruction */
++               this->progress = true;
++            }
++
++            if(!ir->get_next()->is_tail_sentinel()) {
++               assert(this->loop.execute_flag);
++               ir_if* if_execute = new(ir) ir_if(new(ir) ir_dereference_variable(this->loop.execute_flag));
++               move_outer_block_inside(ir, &if_execute->then_instructions);
++               ir->insert_after(if_execute);
++            }
++         }
++      }
++      --this->loop.nesting_depth;
++      --this->function.nesting_depth;
++   }
++
++   virtual void visit(ir_loop *ir)
++   {
++      ++this->function.nesting_depth;
++      loop_record saved_loop = this->loop;
++      this->loop = loop_record(this->function.signature, ir);
++
++      block_record body = visit_block(&ir->body_instructions);
++
++      if(body.min_strength >= strength_break) {
++         /* FINISHME: turn the this->loop into an if, or replace it with its body */
++      }
++
++      if(this->loop.break_flag) {
++         ir_if* break_if = new(ir) ir_if(new(ir) ir_dereference_variable(this->loop.break_flag));
++         break_if->then_instructions.push_tail(new(ir) ir_loop_jump(ir_loop_jump::jump_break));
++         ir->body_instructions.push_tail(break_if);
++      }
++
++      if(this->loop.may_set_return_flag) {
++         assert(this->function.return_flag);
++         ir_if* return_if = new(ir) ir_if(new(ir) ir_dereference_variable(this->function.return_flag));
++         return_if->then_instructions.push_tail(new(ir) ir_loop_jump(saved_loop.loop ? ir_loop_jump::jump_break : ir_loop_jump::jump_continue));
++         ir->insert_after(return_if);
++      }
++
++      this->loop = saved_loop;
++      --this->function.nesting_depth;
++   }
++
++   virtual void visit(ir_function_signature *ir)
++   {
++      /* these are not strictly necessary */
++      assert(!this->function.signature);
++      assert(!this->loop.loop);
++
++      function_record saved_function = this->function;
++      loop_record saved_loop = this->loop;
++      this->function = function_record(ir);
++      this->loop = loop_record(ir);
++
++      assert(!this->loop.loop);
++      visit_block(&ir->body);
++
++      if(this->function.return_value)
++         ir->body.push_tail(new(ir) ir_return(new (ir) ir_dereference_variable(this->function.return_value)));
++
++      this->loop = saved_loop;
++      this->function = saved_function;
++   }
++
++   virtual void visit(class ir_function * ir)
++   {
++      visit_block(&ir->signatures);
++   }
++};
++
++bool
++do_lower_jumps(exec_list *instructions, bool pull_out_jumps, bool lower_sub_return, bool lower_main_return, bool lower_continue, bool lower_break)
++{
++   ir_lower_jumps_visitor v;
++   v.pull_out_jumps = pull_out_jumps;
++   v.lower_continue = lower_continue;
++   v.lower_break = lower_break;
++   v.lower_sub_return = lower_sub_return;
++   v.lower_main_return = lower_main_return;
++
++   do {
++      v.progress = false;
++      visit_exec_list(instructions, &v);
++   } while (v.progress);
++
++   return v.progress;
++}