mirror of https://gitlab.freedesktop.org/mesa/mesa
155 lines
4.3 KiB
C
155 lines
4.3 KiB
C
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/*
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* Copyright © 2019 Broadcom
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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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#include "util/set.h"
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#include "util/dag.h"
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/**
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* Adds a directed edge from the parent node to the child.
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*
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* Both nodes should have been initialized with dag_init_node(). The edge
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* list may contain multiple edges to the same child with different data.
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*/
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void
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dag_add_edge(struct dag_node *parent, struct dag_node *child, void *data)
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{
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util_dynarray_foreach(&parent->edges, struct dag_edge, edge) {
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if (edge->child == child && edge->data == data)
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return;
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}
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/* Remove the child as a DAG head. */
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list_delinit(&child->link);
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struct dag_edge edge = {
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.child = child,
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.data = data,
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};
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util_dynarray_append(&parent->edges, struct dag_edge, edge);
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child->parent_count++;
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}
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/* Removes a single edge from the graph, promoting the child to a DAG head.
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*
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* Note that calling this other than through dag_prune_head() means that you
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* need to be careful when iterating the edges of remaining nodes for NULL
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* children.
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*/
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void
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dag_remove_edge(struct dag *dag, struct dag_edge *edge)
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{
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if (!edge->child)
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return;
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struct dag_node *child = edge->child;
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child->parent_count--;
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if (child->parent_count == 0)
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list_addtail(&child->link, &dag->heads);
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edge->child = NULL;
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edge->data = NULL;
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}
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/**
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* Removes a DAG head from the graph, and moves any new dag heads into the
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* heads list.
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*/
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void
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dag_prune_head(struct dag *dag, struct dag_node *node)
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{
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assert(!node->parent_count);
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list_delinit(&node->link);
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util_dynarray_foreach(&node->edges, struct dag_edge, edge) {
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dag_remove_edge(dag, edge);
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}
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}
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/**
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* Initializes DAG node (probably embedded in some other datastructure in the
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* user).
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*/
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void
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dag_init_node(struct dag *dag, struct dag_node *node)
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{
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util_dynarray_init(&node->edges, dag);
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list_addtail(&node->link, &dag->heads);
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}
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struct dag_traverse_bottom_up_state {
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struct set *seen;
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void *data;
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};
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static void
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dag_traverse_bottom_up_node(struct dag_node *node,
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void (*cb)(struct dag_node *node,
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void *data),
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struct dag_traverse_bottom_up_state *state)
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{
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if (_mesa_set_search(state->seen, node))
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return;
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util_dynarray_foreach(&node->edges, struct dag_edge, edge) {
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dag_traverse_bottom_up_node(edge->child, cb, state);
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}
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cb(node, state->data);
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_mesa_set_add(state->seen, node);
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}
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/**
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* Walks the DAG from leaves to the root, ensuring that each node is only seen
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* once its children have been, and each node is only traversed once.
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*/
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void
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dag_traverse_bottom_up(struct dag *dag, void (*cb)(struct dag_node *node,
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void *data), void *data)
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{
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struct dag_traverse_bottom_up_state state = {
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.seen = _mesa_pointer_set_create(NULL),
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.data = data,
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};
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list_for_each_entry(struct dag_node, node, &dag->heads, link) {
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dag_traverse_bottom_up_node(node, cb, &state);
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}
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ralloc_free(state.seen);
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}
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/**
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* Creates an empty DAG datastructure.
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*/
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struct dag *
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dag_create(void *mem_ctx)
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{
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struct dag *dag = rzalloc(mem_ctx, struct dag);
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list_inithead(&dag->heads);
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return dag;
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}
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