2010-09-27 20:34:33 +01:00
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/*
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* Copyright © 2010 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*
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* Authors:
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* Eric Anholt <eric@anholt.net>
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*
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*/
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/** @file register_allocate.c
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*
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* Graph-coloring register allocator.
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2011-04-24 21:44:32 +01:00
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*
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* The basic idea of graph coloring is to make a node in a graph for
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* every thing that needs a register (color) number assigned, and make
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* edges in the graph between nodes that interfere (can't be allocated
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* to the same register at the same time).
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*
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* During the "simplify" process, any any node with fewer edges than
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* there are registers means that that edge can get assigned a
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* register regardless of what its neighbors choose, so that node is
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* pushed on a stack and removed (with its edges) from the graph.
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* That likely causes other nodes to become trivially colorable as well.
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*
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* Then during the "select" process, nodes are popped off of that
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* stack, their edges restored, and assigned a color different from
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* their neighbors. Because they were pushed on the stack only when
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* they were trivially colorable, any color chosen won't interfere
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* with the registers to be popped later.
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*
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* The downside to most graph coloring is that real hardware often has
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* limitations, like registers that need to be allocated to a node in
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* pairs, or aligned on some boundary. This implementation follows
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* the paper "Retargetable Graph-Coloring Register Allocation for
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* Irregular Architectures" by Johan Runeson and Sven-Olof Nyström.
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*
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* In this system, there are register classes each containing various
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* registers, and registers may interfere with other registers. For
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* example, one might have a class of base registers, and a class of
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* aligned register pairs that would each interfere with their pair of
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* the base registers. Each node has a register class it needs to be
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* assigned to. Define p(B) to be the size of register class B, and
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* q(B,C) to be the number of registers in B that the worst choice
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* register in C could conflict with. Then, this system replaces the
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* basic graph coloring test of "fewer edges from this node than there
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* are registers" with "For this node of class B, the sum of q(B,C)
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* for each neighbor node of class C is less than pB".
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*
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* A nice feature of the pq test is that q(B,C) can be computed once
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* up front and stored in a 2-dimensional array, so that the cost of
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* coloring a node is constant with the number of registers. We do
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* this during ra_set_finalize().
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2010-09-27 20:34:33 +01:00
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*/
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2012-12-01 00:34:09 +00:00
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#include <stdbool.h>
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2010-09-27 20:34:33 +01:00
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2014-09-22 20:24:21 +01:00
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#include "ralloc.h"
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2010-09-27 20:34:33 +01:00
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#include "main/imports.h"
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#include "main/macros.h"
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#include "main/mtypes.h"
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2013-02-20 01:01:41 +00:00
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#include "main/bitset.h"
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2010-09-27 20:34:33 +01:00
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#include "register_allocate.h"
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2011-03-27 06:56:08 +01:00
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#define NO_REG ~0
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2010-09-27 20:34:33 +01:00
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struct ra_reg {
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2014-03-17 21:53:08 +00:00
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BITSET_WORD *conflicts;
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2011-01-18 02:34:43 +00:00
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unsigned int *conflict_list;
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unsigned int conflict_list_size;
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unsigned int num_conflicts;
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2010-09-27 20:34:33 +01:00
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};
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struct ra_regs {
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struct ra_reg *regs;
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unsigned int count;
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struct ra_class **classes;
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unsigned int class_count;
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2012-12-01 00:34:09 +00:00
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bool round_robin;
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2010-09-27 20:34:33 +01:00
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};
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struct ra_class {
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2014-02-22 03:50:15 +00:00
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/**
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* Bitset indicating which registers belong to this class.
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*
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* (If bit N is set, then register N belongs to this class.)
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*/
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BITSET_WORD *regs;
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2010-09-27 20:34:33 +01:00
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/**
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2011-04-24 21:44:32 +01:00
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* p(B) in Runeson/Nyström paper.
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2010-09-27 20:34:33 +01:00
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*
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* This is "how many regs are in the set."
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*/
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unsigned int p;
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/**
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2011-04-24 21:44:32 +01:00
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* q(B,C) (indexed by C, B is this register class) in
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* Runeson/Nyström paper. This is "how many registers of B could
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* the worst choice register from C conflict with".
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2010-09-27 20:34:33 +01:00
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*/
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unsigned int *q;
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};
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struct ra_node {
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2011-04-24 21:44:32 +01:00
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/** @{
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*
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* List of which nodes this node interferes with. This should be
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* symmetric with the other node.
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*/
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2013-02-20 01:01:41 +00:00
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BITSET_WORD *adjacency;
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2011-01-18 08:19:48 +00:00
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unsigned int *adjacency_list;
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2013-02-20 00:46:41 +00:00
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unsigned int adjacency_list_size;
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2010-09-27 20:34:33 +01:00
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unsigned int adjacency_count;
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2011-04-24 21:44:32 +01:00
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/** @} */
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unsigned int class;
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2011-03-27 06:56:08 +01:00
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/* Register, if assigned, or NO_REG. */
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2010-09-27 20:34:33 +01:00
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unsigned int reg;
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2011-04-24 21:44:32 +01:00
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/**
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* Set when the node is in the trivially colorable stack. When
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* set, the adjacency to this node is ignored, to implement the
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* "remove the edge from the graph" in simplification without
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* having to actually modify the adjacency_list.
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*/
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2014-02-22 03:32:24 +00:00
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bool in_stack;
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2011-04-24 21:44:32 +01:00
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2014-08-01 02:57:21 +01:00
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/**
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* The q total, as defined in the Runeson/Nyström paper, for all the
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* interfering nodes not in the stack.
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*/
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unsigned int q_total;
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2011-04-24 21:44:32 +01:00
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/* For an implementation that needs register spilling, this is the
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* approximate cost of spilling this node.
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*/
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2010-10-19 17:25:51 +01:00
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float spill_cost;
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2010-09-27 20:34:33 +01:00
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};
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struct ra_graph {
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struct ra_regs *regs;
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/**
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* the variables that need register allocation.
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*/
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struct ra_node *nodes;
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unsigned int count; /**< count of nodes. */
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unsigned int *stack;
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unsigned int stack_count;
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};
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2012-01-12 20:51:34 +00:00
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/**
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* Creates a set of registers for the allocator.
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*
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* mem_ctx is a ralloc context for the allocator. The reg set may be freed
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* using ralloc_free().
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*/
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2010-09-27 20:34:33 +01:00
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struct ra_regs *
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2012-01-12 20:51:34 +00:00
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ra_alloc_reg_set(void *mem_ctx, unsigned int count)
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2010-09-27 20:34:33 +01:00
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{
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unsigned int i;
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struct ra_regs *regs;
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2012-01-12 20:51:34 +00:00
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regs = rzalloc(mem_ctx, struct ra_regs);
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2010-09-27 20:34:33 +01:00
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regs->count = count;
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2011-01-21 22:32:31 +00:00
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regs->regs = rzalloc_array(regs, struct ra_reg, count);
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2010-09-27 20:34:33 +01:00
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for (i = 0; i < count; i++) {
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2014-03-17 21:53:08 +00:00
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regs->regs[i].conflicts = rzalloc_array(regs->regs, BITSET_WORD,
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BITSET_WORDS(count));
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BITSET_SET(regs->regs[i].conflicts, i);
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2011-01-18 02:34:43 +00:00
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2011-01-21 22:32:31 +00:00
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regs->regs[i].conflict_list = ralloc_array(regs->regs, unsigned int, 4);
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2011-01-18 02:34:43 +00:00
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regs->regs[i].conflict_list_size = 4;
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regs->regs[i].conflict_list[0] = i;
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regs->regs[i].num_conflicts = 1;
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2010-09-27 20:34:33 +01:00
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}
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return regs;
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}
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2012-12-01 00:34:09 +00:00
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/**
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* The register allocator by default prefers to allocate low register numbers,
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* since it was written for hardware (gen4/5 Intel) that is limited in its
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* multithreadedness by the number of registers used in a given shader.
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*
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* However, for hardware without that restriction, densely packed register
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* allocation can put serious constraints on instruction scheduling. This
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* function tells the allocator to rotate around the registers if possible as
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* it allocates the nodes.
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*/
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void
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ra_set_allocate_round_robin(struct ra_regs *regs)
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{
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regs->round_robin = true;
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}
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2011-01-18 02:34:43 +00:00
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static void
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ra_add_conflict_list(struct ra_regs *regs, unsigned int r1, unsigned int r2)
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{
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struct ra_reg *reg1 = ®s->regs[r1];
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if (reg1->conflict_list_size == reg1->num_conflicts) {
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reg1->conflict_list_size *= 2;
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2011-01-21 22:32:31 +00:00
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reg1->conflict_list = reralloc(regs->regs, reg1->conflict_list,
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unsigned int, reg1->conflict_list_size);
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2011-01-18 02:34:43 +00:00
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}
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reg1->conflict_list[reg1->num_conflicts++] = r2;
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2014-03-17 21:53:08 +00:00
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BITSET_SET(reg1->conflicts, r2);
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2011-01-18 02:34:43 +00:00
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}
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2010-09-27 20:34:33 +01:00
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void
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ra_add_reg_conflict(struct ra_regs *regs, unsigned int r1, unsigned int r2)
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{
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2014-03-17 21:53:08 +00:00
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if (!BITSET_TEST(regs->regs[r1].conflicts, r2)) {
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2011-01-18 02:34:43 +00:00
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ra_add_conflict_list(regs, r1, r2);
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ra_add_conflict_list(regs, r2, r1);
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}
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2010-09-27 20:34:33 +01:00
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}
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2011-05-04 21:27:33 +01:00
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/**
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* Adds a conflict between base_reg and reg, and also between reg and
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* anything that base_reg conflicts with.
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*
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* This can simplify code for setting up multiple register classes
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* which are aggregates of some base hardware registers, compared to
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* explicitly using ra_add_reg_conflict.
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*/
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void
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ra_add_transitive_reg_conflict(struct ra_regs *regs,
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unsigned int base_reg, unsigned int reg)
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{
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int i;
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ra_add_reg_conflict(regs, reg, base_reg);
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for (i = 0; i < regs->regs[base_reg].num_conflicts; i++) {
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ra_add_reg_conflict(regs, reg, regs->regs[base_reg].conflict_list[i]);
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}
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}
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2010-09-27 20:34:33 +01:00
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unsigned int
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ra_alloc_reg_class(struct ra_regs *regs)
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{
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struct ra_class *class;
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2011-01-21 22:32:31 +00:00
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regs->classes = reralloc(regs->regs, regs->classes, struct ra_class *,
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regs->class_count + 1);
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2010-09-27 20:34:33 +01:00
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2011-01-21 22:32:31 +00:00
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class = rzalloc(regs, struct ra_class);
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2010-09-27 20:34:33 +01:00
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regs->classes[regs->class_count] = class;
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2014-02-22 03:50:15 +00:00
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class->regs = rzalloc_array(class, BITSET_WORD, BITSET_WORDS(regs->count));
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2010-09-27 20:34:33 +01:00
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return regs->class_count++;
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}
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void
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ra_class_add_reg(struct ra_regs *regs, unsigned int c, unsigned int r)
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{
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struct ra_class *class = regs->classes[c];
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2014-02-22 03:50:15 +00:00
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BITSET_SET(class->regs, r);
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2010-09-27 20:34:33 +01:00
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class->p++;
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}
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2014-02-22 03:31:44 +00:00
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/**
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* Returns true if the register belongs to the given class.
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*/
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static bool
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reg_belongs_to_class(unsigned int r, struct ra_class *c)
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{
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2014-02-22 03:50:15 +00:00
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return BITSET_TEST(c->regs, r);
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2014-02-22 03:31:44 +00:00
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}
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2010-09-27 20:34:33 +01:00
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/**
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* Must be called after all conflicts and register classes have been
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* set up and before the register set is used for allocation.
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2012-09-03 15:43:45 +01:00
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* To avoid costly q value computation, use the q_values paramater
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* to pass precomputed q values to this function.
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2010-09-27 20:34:33 +01:00
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*/
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void
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2012-09-03 15:43:45 +01:00
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ra_set_finalize(struct ra_regs *regs, unsigned int **q_values)
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2010-09-27 20:34:33 +01:00
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{
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unsigned int b, c;
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for (b = 0; b < regs->class_count; b++) {
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2011-01-21 22:32:31 +00:00
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regs->classes[b]->q = ralloc_array(regs, unsigned int, regs->class_count);
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2010-09-27 20:34:33 +01:00
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}
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2012-09-03 15:43:45 +01:00
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if (q_values) {
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for (b = 0; b < regs->class_count; b++) {
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for (c = 0; c < regs->class_count; c++) {
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regs->classes[b]->q[c] = q_values[b][c];
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}
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}
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return;
|
|
|
|
}
|
|
|
|
|
2010-09-27 20:34:33 +01:00
|
|
|
/* Compute, for each class B and C, how many regs of B an
|
|
|
|
* allocation to C could conflict with.
|
|
|
|
*/
|
|
|
|
for (b = 0; b < regs->class_count; b++) {
|
|
|
|
for (c = 0; c < regs->class_count; c++) {
|
|
|
|
unsigned int rc;
|
|
|
|
int max_conflicts = 0;
|
|
|
|
|
|
|
|
for (rc = 0; rc < regs->count; rc++) {
|
|
|
|
int conflicts = 0;
|
2011-01-18 02:34:43 +00:00
|
|
|
int i;
|
2010-09-27 20:34:33 +01:00
|
|
|
|
2014-02-22 03:31:44 +00:00
|
|
|
if (!reg_belongs_to_class(rc, regs->classes[c]))
|
2010-09-27 20:34:33 +01:00
|
|
|
continue;
|
|
|
|
|
2011-01-18 02:34:43 +00:00
|
|
|
for (i = 0; i < regs->regs[rc].num_conflicts; i++) {
|
|
|
|
unsigned int rb = regs->regs[rc].conflict_list[i];
|
2014-10-04 02:08:12 +01:00
|
|
|
if (reg_belongs_to_class(rb, regs->classes[b]))
|
2010-09-27 20:34:33 +01:00
|
|
|
conflicts++;
|
|
|
|
}
|
|
|
|
max_conflicts = MAX2(max_conflicts, conflicts);
|
|
|
|
}
|
|
|
|
regs->classes[b]->q[c] = max_conflicts;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2011-01-18 08:19:48 +00:00
|
|
|
static void
|
|
|
|
ra_add_node_adjacency(struct ra_graph *g, unsigned int n1, unsigned int n2)
|
|
|
|
{
|
2013-02-20 01:01:41 +00:00
|
|
|
BITSET_SET(g->nodes[n1].adjacency, n2);
|
2013-02-20 00:46:41 +00:00
|
|
|
|
2014-08-01 02:57:21 +01:00
|
|
|
if (n1 != n2) {
|
|
|
|
int n1_class = g->nodes[n1].class;
|
|
|
|
int n2_class = g->nodes[n2].class;
|
|
|
|
g->nodes[n1].q_total += g->regs->classes[n1_class]->q[n2_class];
|
|
|
|
}
|
|
|
|
|
2013-02-20 00:46:41 +00:00
|
|
|
if (g->nodes[n1].adjacency_count >=
|
|
|
|
g->nodes[n1].adjacency_list_size) {
|
|
|
|
g->nodes[n1].adjacency_list_size *= 2;
|
|
|
|
g->nodes[n1].adjacency_list = reralloc(g, g->nodes[n1].adjacency_list,
|
|
|
|
unsigned int,
|
|
|
|
g->nodes[n1].adjacency_list_size);
|
|
|
|
}
|
|
|
|
|
2011-01-18 08:19:48 +00:00
|
|
|
g->nodes[n1].adjacency_list[g->nodes[n1].adjacency_count] = n2;
|
|
|
|
g->nodes[n1].adjacency_count++;
|
|
|
|
}
|
|
|
|
|
2010-09-27 20:34:33 +01:00
|
|
|
struct ra_graph *
|
|
|
|
ra_alloc_interference_graph(struct ra_regs *regs, unsigned int count)
|
|
|
|
{
|
|
|
|
struct ra_graph *g;
|
|
|
|
unsigned int i;
|
|
|
|
|
2014-11-21 07:46:03 +00:00
|
|
|
g = rzalloc(NULL, struct ra_graph);
|
2010-09-27 20:34:33 +01:00
|
|
|
g->regs = regs;
|
2011-01-21 22:32:31 +00:00
|
|
|
g->nodes = rzalloc_array(g, struct ra_node, count);
|
2010-09-27 20:34:33 +01:00
|
|
|
g->count = count;
|
|
|
|
|
2011-01-21 22:32:31 +00:00
|
|
|
g->stack = rzalloc_array(g, unsigned int, count);
|
2010-09-27 20:34:33 +01:00
|
|
|
|
|
|
|
for (i = 0; i < count; i++) {
|
2013-04-04 17:47:03 +01:00
|
|
|
int bitset_count = BITSET_WORDS(count);
|
2013-02-20 01:01:41 +00:00
|
|
|
g->nodes[i].adjacency = rzalloc_array(g, BITSET_WORD, bitset_count);
|
|
|
|
|
2013-02-20 00:46:41 +00:00
|
|
|
g->nodes[i].adjacency_list_size = 4;
|
|
|
|
g->nodes[i].adjacency_list =
|
|
|
|
ralloc_array(g, unsigned int, g->nodes[i].adjacency_list_size);
|
2011-01-18 08:19:48 +00:00
|
|
|
g->nodes[i].adjacency_count = 0;
|
2014-08-01 02:57:21 +01:00
|
|
|
g->nodes[i].q_total = 0;
|
2013-02-20 01:01:41 +00:00
|
|
|
|
2011-01-18 08:19:48 +00:00
|
|
|
ra_add_node_adjacency(g, i, i);
|
2011-03-27 06:56:08 +01:00
|
|
|
g->nodes[i].reg = NO_REG;
|
2010-09-27 20:34:33 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
return g;
|
|
|
|
}
|
|
|
|
|
|
|
|
void
|
|
|
|
ra_set_node_class(struct ra_graph *g,
|
|
|
|
unsigned int n, unsigned int class)
|
|
|
|
{
|
|
|
|
g->nodes[n].class = class;
|
|
|
|
}
|
|
|
|
|
|
|
|
void
|
|
|
|
ra_add_node_interference(struct ra_graph *g,
|
|
|
|
unsigned int n1, unsigned int n2)
|
|
|
|
{
|
2013-02-20 01:01:41 +00:00
|
|
|
if (!BITSET_TEST(g->nodes[n1].adjacency, n2)) {
|
2011-01-18 08:19:48 +00:00
|
|
|
ra_add_node_adjacency(g, n1, n2);
|
|
|
|
ra_add_node_adjacency(g, n2, n1);
|
|
|
|
}
|
2010-09-27 20:34:33 +01:00
|
|
|
}
|
|
|
|
|
2014-02-22 03:32:24 +00:00
|
|
|
static bool
|
|
|
|
pq_test(struct ra_graph *g, unsigned int n)
|
2010-09-27 20:34:33 +01:00
|
|
|
{
|
|
|
|
int n_class = g->nodes[n].class;
|
|
|
|
|
2014-08-01 02:57:21 +01:00
|
|
|
return g->nodes[n].q_total < g->regs->classes[n_class]->p;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void
|
|
|
|
decrement_q(struct ra_graph *g, unsigned int n)
|
|
|
|
{
|
|
|
|
unsigned int i;
|
|
|
|
int n_class = g->nodes[n].class;
|
|
|
|
|
|
|
|
for (i = 0; i < g->nodes[n].adjacency_count; i++) {
|
|
|
|
unsigned int n2 = g->nodes[n].adjacency_list[i];
|
2011-01-18 08:19:48 +00:00
|
|
|
unsigned int n2_class = g->nodes[n2].class;
|
2010-09-27 20:34:33 +01:00
|
|
|
|
2011-01-18 08:19:48 +00:00
|
|
|
if (n != n2 && !g->nodes[n2].in_stack) {
|
2014-09-06 01:59:32 +01:00
|
|
|
assert(g->nodes[n2].q_total >= g->regs->classes[n2_class]->q[n_class]);
|
2014-08-01 02:57:21 +01:00
|
|
|
g->nodes[n2].q_total -= g->regs->classes[n2_class]->q[n_class];
|
2010-09-27 20:34:33 +01:00
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* Simplifies the interference graph by pushing all
|
|
|
|
* trivially-colorable nodes into a stack of nodes to be colored,
|
|
|
|
* removing them from the graph, and rinsing and repeating.
|
|
|
|
*
|
2014-08-01 02:57:23 +01:00
|
|
|
* If we encounter a case where we can't push any nodes on the stack, then
|
|
|
|
* we optimistically choose a node and push it on the stack. We heuristically
|
|
|
|
* push the node with the lowest total q value, since it has the fewest
|
|
|
|
* neighbors and therefore is most likely to be allocated.
|
2010-09-27 20:34:33 +01:00
|
|
|
*/
|
2014-08-01 02:57:23 +01:00
|
|
|
static void
|
2010-09-27 20:34:33 +01:00
|
|
|
ra_simplify(struct ra_graph *g)
|
|
|
|
{
|
2014-02-22 03:32:24 +00:00
|
|
|
bool progress = true;
|
2010-09-27 20:34:33 +01:00
|
|
|
int i;
|
|
|
|
|
|
|
|
while (progress) {
|
2014-08-01 02:57:23 +01:00
|
|
|
unsigned int best_optimistic_node = ~0;
|
|
|
|
unsigned int lowest_q_total = ~0;
|
|
|
|
|
2014-08-14 15:44:06 +01:00
|
|
|
progress = false;
|
|
|
|
|
2010-09-27 20:34:33 +01:00
|
|
|
for (i = g->count - 1; i >= 0; i--) {
|
2011-03-27 06:56:08 +01:00
|
|
|
if (g->nodes[i].in_stack || g->nodes[i].reg != NO_REG)
|
2010-09-27 20:34:33 +01:00
|
|
|
continue;
|
|
|
|
|
|
|
|
if (pq_test(g, i)) {
|
2014-08-01 02:57:21 +01:00
|
|
|
decrement_q(g, i);
|
2010-09-27 20:34:33 +01:00
|
|
|
g->stack[g->stack_count] = i;
|
|
|
|
g->stack_count++;
|
2014-02-22 03:32:24 +00:00
|
|
|
g->nodes[i].in_stack = true;
|
|
|
|
progress = true;
|
2014-08-01 02:57:23 +01:00
|
|
|
} else {
|
|
|
|
unsigned int new_q_total = g->nodes[i].q_total;
|
|
|
|
if (new_q_total < lowest_q_total) {
|
|
|
|
best_optimistic_node = i;
|
|
|
|
lowest_q_total = new_q_total;
|
|
|
|
}
|
2010-09-27 20:34:33 +01:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2014-08-01 02:57:23 +01:00
|
|
|
if (!progress && best_optimistic_node != ~0) {
|
|
|
|
decrement_q(g, best_optimistic_node);
|
|
|
|
g->stack[g->stack_count] = best_optimistic_node;
|
|
|
|
g->stack_count++;
|
|
|
|
g->nodes[best_optimistic_node].in_stack = true;
|
|
|
|
progress = true;
|
|
|
|
}
|
2010-09-27 20:34:33 +01:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* Pops nodes from the stack back into the graph, coloring them with
|
|
|
|
* registers as they go.
|
|
|
|
*
|
|
|
|
* If all nodes were trivially colorable, then this must succeed. If
|
2014-02-22 03:32:24 +00:00
|
|
|
* not (optimistic coloring), then it may return false;
|
2010-09-27 20:34:33 +01:00
|
|
|
*/
|
2014-08-01 02:57:20 +01:00
|
|
|
static bool
|
2010-09-27 20:34:33 +01:00
|
|
|
ra_select(struct ra_graph *g)
|
|
|
|
{
|
|
|
|
int i;
|
2012-12-01 00:34:09 +00:00
|
|
|
int start_search_reg = 0;
|
2010-09-27 20:34:33 +01:00
|
|
|
|
|
|
|
while (g->stack_count != 0) {
|
2012-12-01 00:34:09 +00:00
|
|
|
unsigned int ri;
|
|
|
|
unsigned int r = -1;
|
2010-09-27 20:34:33 +01:00
|
|
|
int n = g->stack[g->stack_count - 1];
|
|
|
|
struct ra_class *c = g->regs->classes[g->nodes[n].class];
|
|
|
|
|
|
|
|
/* Find the lowest-numbered reg which is not used by a member
|
|
|
|
* of the graph adjacent to us.
|
|
|
|
*/
|
2012-12-01 00:34:09 +00:00
|
|
|
for (ri = 0; ri < g->regs->count; ri++) {
|
|
|
|
r = (start_search_reg + ri) % g->regs->count;
|
2014-02-22 03:31:44 +00:00
|
|
|
if (!reg_belongs_to_class(r, c))
|
2010-09-27 20:34:33 +01:00
|
|
|
continue;
|
|
|
|
|
|
|
|
/* Check if any of our neighbors conflict with this register choice. */
|
2011-01-18 08:33:35 +00:00
|
|
|
for (i = 0; i < g->nodes[n].adjacency_count; i++) {
|
|
|
|
unsigned int n2 = g->nodes[n].adjacency_list[i];
|
|
|
|
|
|
|
|
if (!g->nodes[n2].in_stack &&
|
2014-03-17 21:53:08 +00:00
|
|
|
BITSET_TEST(g->regs->regs[r].conflicts, g->nodes[n2].reg)) {
|
2010-09-27 20:34:33 +01:00
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
2011-01-18 08:33:35 +00:00
|
|
|
if (i == g->nodes[n].adjacency_count)
|
2010-09-27 20:34:33 +01:00
|
|
|
break;
|
|
|
|
}
|
2014-08-01 02:57:22 +01:00
|
|
|
|
|
|
|
/* set this to false even if we return here so that
|
|
|
|
* ra_get_best_spill_node() considers this node later.
|
|
|
|
*/
|
|
|
|
g->nodes[n].in_stack = false;
|
|
|
|
|
2012-12-01 00:34:09 +00:00
|
|
|
if (ri == g->regs->count)
|
2014-02-22 03:32:24 +00:00
|
|
|
return false;
|
2010-09-27 20:34:33 +01:00
|
|
|
|
|
|
|
g->nodes[n].reg = r;
|
|
|
|
g->stack_count--;
|
2012-12-01 00:34:09 +00:00
|
|
|
|
|
|
|
if (g->regs->round_robin)
|
|
|
|
start_search_reg = r + 1;
|
2010-09-27 20:34:33 +01:00
|
|
|
}
|
|
|
|
|
2014-02-22 03:32:24 +00:00
|
|
|
return true;
|
2010-09-27 20:34:33 +01:00
|
|
|
}
|
|
|
|
|
2014-02-22 03:32:24 +00:00
|
|
|
bool
|
2014-08-01 02:57:20 +01:00
|
|
|
ra_allocate(struct ra_graph *g)
|
2010-09-27 20:34:33 +01:00
|
|
|
{
|
2014-08-01 02:57:23 +01:00
|
|
|
ra_simplify(g);
|
2010-09-27 20:34:33 +01:00
|
|
|
return ra_select(g);
|
|
|
|
}
|
|
|
|
|
|
|
|
unsigned int
|
|
|
|
ra_get_node_reg(struct ra_graph *g, unsigned int n)
|
|
|
|
{
|
|
|
|
return g->nodes[n].reg;
|
|
|
|
}
|
2010-10-19 17:25:51 +01:00
|
|
|
|
2011-03-27 06:56:08 +01:00
|
|
|
/**
|
|
|
|
* Forces a node to a specific register. This can be used to avoid
|
|
|
|
* creating a register class containing one node when handling data
|
|
|
|
* that must live in a fixed location and is known to not conflict
|
|
|
|
* with other forced register assignment (as is common with shader
|
|
|
|
* input data). These nodes do not end up in the stack during
|
|
|
|
* ra_simplify(), and thus at ra_select() time it is as if they were
|
|
|
|
* the first popped off the stack and assigned their fixed locations.
|
2012-09-03 13:23:02 +01:00
|
|
|
* Nodes that use this function do not need to be assigned a register
|
|
|
|
* class.
|
2011-03-27 06:56:08 +01:00
|
|
|
*
|
|
|
|
* Must be called before ra_simplify().
|
|
|
|
*/
|
|
|
|
void
|
|
|
|
ra_set_node_reg(struct ra_graph *g, unsigned int n, unsigned int reg)
|
|
|
|
{
|
|
|
|
g->nodes[n].reg = reg;
|
2014-02-22 03:32:24 +00:00
|
|
|
g->nodes[n].in_stack = false;
|
2011-03-27 06:56:08 +01:00
|
|
|
}
|
|
|
|
|
2010-10-19 17:25:51 +01:00
|
|
|
static float
|
|
|
|
ra_get_spill_benefit(struct ra_graph *g, unsigned int n)
|
|
|
|
{
|
|
|
|
int j;
|
|
|
|
float benefit = 0;
|
|
|
|
int n_class = g->nodes[n].class;
|
|
|
|
|
2011-01-18 09:08:51 +00:00
|
|
|
/* Define the benefit of eliminating an interference between n, n2
|
2010-10-19 17:25:51 +01:00
|
|
|
* through spilling as q(C, B) / p(C). This is similar to the
|
|
|
|
* "count number of edges" approach of traditional graph coloring,
|
|
|
|
* but takes classes into account.
|
|
|
|
*/
|
2011-01-18 09:08:51 +00:00
|
|
|
for (j = 0; j < g->nodes[n].adjacency_count; j++) {
|
|
|
|
unsigned int n2 = g->nodes[n].adjacency_list[j];
|
|
|
|
if (n != n2) {
|
|
|
|
unsigned int n2_class = g->nodes[n2].class;
|
|
|
|
benefit += ((float)g->regs->classes[n_class]->q[n2_class] /
|
2010-10-19 17:25:51 +01:00
|
|
|
g->regs->classes[n_class]->p);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
return benefit;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* Returns a node number to be spilled according to the cost/benefit using
|
|
|
|
* the pq test, or -1 if there are no spillable nodes.
|
|
|
|
*/
|
|
|
|
int
|
|
|
|
ra_get_best_spill_node(struct ra_graph *g)
|
|
|
|
{
|
|
|
|
unsigned int best_node = -1;
|
2013-04-02 21:38:07 +01:00
|
|
|
float best_benefit = 0.0;
|
2014-08-01 02:57:22 +01:00
|
|
|
unsigned int n;
|
2010-10-19 17:25:51 +01:00
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2014-08-01 02:57:22 +01:00
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/* Consider any nodes that we colored successfully or the node we failed to
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* color for spilling. When we failed to color a node in ra_select(), we
|
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* only considered these nodes, so spilling any other ones would not result
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* in us making progress.
|
2013-06-06 21:21:21 +01:00
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*/
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2010-10-19 17:25:51 +01:00
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for (n = 0; n < g->count; n++) {
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float cost = g->nodes[n].spill_cost;
|
2010-10-22 15:59:06 +01:00
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|
float benefit;
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2010-10-19 17:25:51 +01:00
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|
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if (cost <= 0.0)
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|
continue;
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|
2012-09-28 22:21:38 +01:00
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|
if (g->nodes[n].in_stack)
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continue;
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2010-10-22 15:59:06 +01:00
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benefit = ra_get_spill_benefit(g, n);
|
2010-10-19 17:25:51 +01:00
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|
if (benefit / cost > best_benefit) {
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|
best_benefit = benefit / cost;
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|
|
best_node = n;
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|
}
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|
|
}
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|
|
return best_node;
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|
|
}
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|
|
/**
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|
* Only nodes with a spill cost set (cost != 0.0) will be considered
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|
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* for register spilling.
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|
*/
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|
void
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|
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ra_set_node_spill_cost(struct ra_graph *g, unsigned int n, float cost)
|
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|
|
{
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|
|
g->nodes[n].spill_cost = cost;
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|
|
|
}
|