/* Calculate (post)dominators in slightly super-linear time.
|
/* Calculate (post)dominators in slightly super-linear time.
|
Copyright (C) 2000, 2003, 2004, 2005, 2007 Free Software Foundation, Inc.
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Copyright (C) 2000, 2003, 2004, 2005, 2007 Free Software Foundation, Inc.
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Contributed by Michael Matz (matz@ifh.de).
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Contributed by Michael Matz (matz@ifh.de).
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|
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This file is part of GCC.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it
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GCC is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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the Free Software Foundation; either version 3, or (at your option)
|
any later version.
|
any later version.
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|
|
GCC is distributed in the hope that it will be useful, but WITHOUT
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GCC is distributed in the hope that it will be useful, but WITHOUT
|
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
|
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
|
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
|
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
|
License for more details.
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License for more details.
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|
|
You should have received a copy of the GNU General Public License
|
You should have received a copy of the GNU General Public License
|
along with GCC; see the file COPYING3. If not see
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along with GCC; see the file COPYING3. If not see
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<http://www.gnu.org/licenses/>. */
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<http://www.gnu.org/licenses/>. */
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|
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/* This file implements the well known algorithm from Lengauer and Tarjan
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/* This file implements the well known algorithm from Lengauer and Tarjan
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to compute the dominators in a control flow graph. A basic block D is said
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to compute the dominators in a control flow graph. A basic block D is said
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to dominate another block X, when all paths from the entry node of the CFG
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to dominate another block X, when all paths from the entry node of the CFG
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to X go also over D. The dominance relation is a transitive reflexive
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to X go also over D. The dominance relation is a transitive reflexive
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relation and its minimal transitive reduction is a tree, called the
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relation and its minimal transitive reduction is a tree, called the
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dominator tree. So for each block X besides the entry block exists a
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dominator tree. So for each block X besides the entry block exists a
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block I(X), called the immediate dominator of X, which is the parent of X
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block I(X), called the immediate dominator of X, which is the parent of X
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in the dominator tree.
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in the dominator tree.
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|
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The algorithm computes this dominator tree implicitly by computing for
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The algorithm computes this dominator tree implicitly by computing for
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each block its immediate dominator. We use tree balancing and path
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each block its immediate dominator. We use tree balancing and path
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compression, so it's the O(e*a(e,v)) variant, where a(e,v) is the very
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compression, so it's the O(e*a(e,v)) variant, where a(e,v) is the very
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slowly growing functional inverse of the Ackerman function. */
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slowly growing functional inverse of the Ackerman function. */
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|
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#include "config.h"
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#include "config.h"
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#include "system.h"
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#include "system.h"
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#include "coretypes.h"
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#include "coretypes.h"
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#include "tm.h"
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#include "tm.h"
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#include "rtl.h"
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#include "rtl.h"
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#include "hard-reg-set.h"
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#include "hard-reg-set.h"
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#include "obstack.h"
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#include "obstack.h"
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#include "basic-block.h"
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#include "basic-block.h"
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#include "toplev.h"
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#include "toplev.h"
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#include "et-forest.h"
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#include "et-forest.h"
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#include "timevar.h"
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#include "timevar.h"
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|
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/* Whether the dominators and the postdominators are available. */
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/* Whether the dominators and the postdominators are available. */
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enum dom_state dom_computed[2];
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enum dom_state dom_computed[2];
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|
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/* We name our nodes with integers, beginning with 1. Zero is reserved for
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/* We name our nodes with integers, beginning with 1. Zero is reserved for
|
'undefined' or 'end of list'. The name of each node is given by the dfs
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'undefined' or 'end of list'. The name of each node is given by the dfs
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number of the corresponding basic block. Please note, that we include the
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number of the corresponding basic block. Please note, that we include the
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artificial ENTRY_BLOCK (or EXIT_BLOCK in the post-dom case) in our lists to
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artificial ENTRY_BLOCK (or EXIT_BLOCK in the post-dom case) in our lists to
|
support multiple entry points. Its dfs number is of course 1. */
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support multiple entry points. Its dfs number is of course 1. */
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|
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/* Type of Basic Block aka. TBB */
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/* Type of Basic Block aka. TBB */
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typedef unsigned int TBB;
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typedef unsigned int TBB;
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|
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/* We work in a poor-mans object oriented fashion, and carry an instance of
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/* We work in a poor-mans object oriented fashion, and carry an instance of
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this structure through all our 'methods'. It holds various arrays
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this structure through all our 'methods'. It holds various arrays
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reflecting the (sub)structure of the flowgraph. Most of them are of type
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reflecting the (sub)structure of the flowgraph. Most of them are of type
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TBB and are also indexed by TBB. */
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TBB and are also indexed by TBB. */
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|
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struct dom_info
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struct dom_info
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{
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{
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/* The parent of a node in the DFS tree. */
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/* The parent of a node in the DFS tree. */
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TBB *dfs_parent;
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TBB *dfs_parent;
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/* For a node x key[x] is roughly the node nearest to the root from which
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/* For a node x key[x] is roughly the node nearest to the root from which
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exists a way to x only over nodes behind x. Such a node is also called
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exists a way to x only over nodes behind x. Such a node is also called
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semidominator. */
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semidominator. */
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TBB *key;
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TBB *key;
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/* The value in path_min[x] is the node y on the path from x to the root of
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/* The value in path_min[x] is the node y on the path from x to the root of
|
the tree x is in with the smallest key[y]. */
|
the tree x is in with the smallest key[y]. */
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TBB *path_min;
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TBB *path_min;
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/* bucket[x] points to the first node of the set of nodes having x as key. */
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/* bucket[x] points to the first node of the set of nodes having x as key. */
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TBB *bucket;
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TBB *bucket;
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/* And next_bucket[x] points to the next node. */
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/* And next_bucket[x] points to the next node. */
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TBB *next_bucket;
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TBB *next_bucket;
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/* After the algorithm is done, dom[x] contains the immediate dominator
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/* After the algorithm is done, dom[x] contains the immediate dominator
|
of x. */
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of x. */
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TBB *dom;
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TBB *dom;
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|
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/* The following few fields implement the structures needed for disjoint
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/* The following few fields implement the structures needed for disjoint
|
sets. */
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sets. */
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/* set_chain[x] is the next node on the path from x to the representant
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/* set_chain[x] is the next node on the path from x to the representant
|
of the set containing x. If set_chain[x]==0 then x is a root. */
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of the set containing x. If set_chain[x]==0 then x is a root. */
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TBB *set_chain;
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TBB *set_chain;
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/* set_size[x] is the number of elements in the set named by x. */
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/* set_size[x] is the number of elements in the set named by x. */
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unsigned int *set_size;
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unsigned int *set_size;
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/* set_child[x] is used for balancing the tree representing a set. It can
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/* set_child[x] is used for balancing the tree representing a set. It can
|
be understood as the next sibling of x. */
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be understood as the next sibling of x. */
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TBB *set_child;
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TBB *set_child;
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|
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/* If b is the number of a basic block (BB->index), dfs_order[b] is the
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/* If b is the number of a basic block (BB->index), dfs_order[b] is the
|
number of that node in DFS order counted from 1. This is an index
|
number of that node in DFS order counted from 1. This is an index
|
into most of the other arrays in this structure. */
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into most of the other arrays in this structure. */
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TBB *dfs_order;
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TBB *dfs_order;
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/* If x is the DFS-index of a node which corresponds with a basic block,
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/* If x is the DFS-index of a node which corresponds with a basic block,
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dfs_to_bb[x] is that basic block. Note, that in our structure there are
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dfs_to_bb[x] is that basic block. Note, that in our structure there are
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more nodes that basic blocks, so only dfs_to_bb[dfs_order[bb->index]]==bb
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more nodes that basic blocks, so only dfs_to_bb[dfs_order[bb->index]]==bb
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is true for every basic block bb, but not the opposite. */
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is true for every basic block bb, but not the opposite. */
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basic_block *dfs_to_bb;
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basic_block *dfs_to_bb;
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|
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/* This is the next free DFS number when creating the DFS tree. */
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/* This is the next free DFS number when creating the DFS tree. */
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unsigned int dfsnum;
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unsigned int dfsnum;
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/* The number of nodes in the DFS tree (==dfsnum-1). */
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/* The number of nodes in the DFS tree (==dfsnum-1). */
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unsigned int nodes;
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unsigned int nodes;
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|
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/* Blocks with bits set here have a fake edge to EXIT. These are used
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/* Blocks with bits set here have a fake edge to EXIT. These are used
|
to turn a DFS forest into a proper tree. */
|
to turn a DFS forest into a proper tree. */
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bitmap fake_exit_edge;
|
bitmap fake_exit_edge;
|
};
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};
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|
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static void init_dom_info (struct dom_info *, enum cdi_direction);
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static void init_dom_info (struct dom_info *, enum cdi_direction);
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static void free_dom_info (struct dom_info *);
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static void free_dom_info (struct dom_info *);
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static void calc_dfs_tree_nonrec (struct dom_info *, basic_block,
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static void calc_dfs_tree_nonrec (struct dom_info *, basic_block,
|
enum cdi_direction);
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enum cdi_direction);
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static void calc_dfs_tree (struct dom_info *, enum cdi_direction);
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static void calc_dfs_tree (struct dom_info *, enum cdi_direction);
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static void compress (struct dom_info *, TBB);
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static void compress (struct dom_info *, TBB);
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static TBB eval (struct dom_info *, TBB);
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static TBB eval (struct dom_info *, TBB);
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static void link_roots (struct dom_info *, TBB, TBB);
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static void link_roots (struct dom_info *, TBB, TBB);
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static void calc_idoms (struct dom_info *, enum cdi_direction);
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static void calc_idoms (struct dom_info *, enum cdi_direction);
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void debug_dominance_info (enum cdi_direction);
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void debug_dominance_info (enum cdi_direction);
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|
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/* Keeps track of the*/
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/* Keeps track of the*/
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static unsigned n_bbs_in_dom_tree[2];
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static unsigned n_bbs_in_dom_tree[2];
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|
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/* Helper macro for allocating and initializing an array,
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/* Helper macro for allocating and initializing an array,
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for aesthetic reasons. */
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for aesthetic reasons. */
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#define init_ar(var, type, num, content) \
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#define init_ar(var, type, num, content) \
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do \
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do \
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{ \
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{ \
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unsigned int i = 1; /* Catch content == i. */ \
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unsigned int i = 1; /* Catch content == i. */ \
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if (! (content)) \
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if (! (content)) \
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(var) = XCNEWVEC (type, num); \
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(var) = XCNEWVEC (type, num); \
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else \
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else \
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{ \
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{ \
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(var) = XNEWVEC (type, (num)); \
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(var) = XNEWVEC (type, (num)); \
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for (i = 0; i < num; i++) \
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for (i = 0; i < num; i++) \
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(var)[i] = (content); \
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(var)[i] = (content); \
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} \
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} \
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} \
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} \
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while (0)
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while (0)
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|
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/* Allocate all needed memory in a pessimistic fashion (so we round up).
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/* Allocate all needed memory in a pessimistic fashion (so we round up).
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This initializes the contents of DI, which already must be allocated. */
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This initializes the contents of DI, which already must be allocated. */
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|
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static void
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static void
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init_dom_info (struct dom_info *di, enum cdi_direction dir)
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init_dom_info (struct dom_info *di, enum cdi_direction dir)
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{
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{
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unsigned int num = n_basic_blocks;
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unsigned int num = n_basic_blocks;
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init_ar (di->dfs_parent, TBB, num, 0);
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init_ar (di->dfs_parent, TBB, num, 0);
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init_ar (di->path_min, TBB, num, i);
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init_ar (di->path_min, TBB, num, i);
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init_ar (di->key, TBB, num, i);
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init_ar (di->key, TBB, num, i);
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init_ar (di->dom, TBB, num, 0);
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init_ar (di->dom, TBB, num, 0);
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|
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init_ar (di->bucket, TBB, num, 0);
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init_ar (di->bucket, TBB, num, 0);
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init_ar (di->next_bucket, TBB, num, 0);
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init_ar (di->next_bucket, TBB, num, 0);
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|
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init_ar (di->set_chain, TBB, num, 0);
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init_ar (di->set_chain, TBB, num, 0);
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init_ar (di->set_size, unsigned int, num, 1);
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init_ar (di->set_size, unsigned int, num, 1);
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init_ar (di->set_child, TBB, num, 0);
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init_ar (di->set_child, TBB, num, 0);
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|
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init_ar (di->dfs_order, TBB, (unsigned int) last_basic_block + 1, 0);
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init_ar (di->dfs_order, TBB, (unsigned int) last_basic_block + 1, 0);
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init_ar (di->dfs_to_bb, basic_block, num, 0);
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init_ar (di->dfs_to_bb, basic_block, num, 0);
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di->dfsnum = 1;
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di->dfsnum = 1;
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di->nodes = 0;
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di->nodes = 0;
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|
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di->fake_exit_edge = dir ? BITMAP_ALLOC (NULL) : NULL;
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di->fake_exit_edge = dir ? BITMAP_ALLOC (NULL) : NULL;
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}
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}
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|
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#undef init_ar
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#undef init_ar
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|
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/* Free all allocated memory in DI, but not DI itself. */
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/* Free all allocated memory in DI, but not DI itself. */
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|
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static void
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static void
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free_dom_info (struct dom_info *di)
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free_dom_info (struct dom_info *di)
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{
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{
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free (di->dfs_parent);
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free (di->dfs_parent);
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free (di->path_min);
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free (di->path_min);
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free (di->key);
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free (di->key);
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free (di->dom);
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free (di->dom);
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free (di->bucket);
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free (di->bucket);
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free (di->next_bucket);
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free (di->next_bucket);
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free (di->set_chain);
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free (di->set_chain);
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free (di->set_size);
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free (di->set_size);
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free (di->set_child);
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free (di->set_child);
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free (di->dfs_order);
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free (di->dfs_order);
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free (di->dfs_to_bb);
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free (di->dfs_to_bb);
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BITMAP_FREE (di->fake_exit_edge);
|
BITMAP_FREE (di->fake_exit_edge);
|
}
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}
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|
|
/* The nonrecursive variant of creating a DFS tree. DI is our working
|
/* The nonrecursive variant of creating a DFS tree. DI is our working
|
structure, BB the starting basic block for this tree and REVERSE
|
structure, BB the starting basic block for this tree and REVERSE
|
is true, if predecessors should be visited instead of successors of a
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is true, if predecessors should be visited instead of successors of a
|
node. After this is done all nodes reachable from BB were visited, have
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node. After this is done all nodes reachable from BB were visited, have
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assigned their dfs number and are linked together to form a tree. */
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assigned their dfs number and are linked together to form a tree. */
|
|
|
static void
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static void
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calc_dfs_tree_nonrec (struct dom_info *di, basic_block bb,
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calc_dfs_tree_nonrec (struct dom_info *di, basic_block bb,
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enum cdi_direction reverse)
|
enum cdi_direction reverse)
|
{
|
{
|
/* We call this _only_ if bb is not already visited. */
|
/* We call this _only_ if bb is not already visited. */
|
edge e;
|
edge e;
|
TBB child_i, my_i = 0;
|
TBB child_i, my_i = 0;
|
edge_iterator *stack;
|
edge_iterator *stack;
|
edge_iterator ei, einext;
|
edge_iterator ei, einext;
|
int sp;
|
int sp;
|
/* Start block (ENTRY_BLOCK_PTR for forward problem, EXIT_BLOCK for backward
|
/* Start block (ENTRY_BLOCK_PTR for forward problem, EXIT_BLOCK for backward
|
problem). */
|
problem). */
|
basic_block en_block;
|
basic_block en_block;
|
/* Ending block. */
|
/* Ending block. */
|
basic_block ex_block;
|
basic_block ex_block;
|
|
|
stack = XNEWVEC (edge_iterator, n_basic_blocks + 1);
|
stack = XNEWVEC (edge_iterator, n_basic_blocks + 1);
|
sp = 0;
|
sp = 0;
|
|
|
/* Initialize our border blocks, and the first edge. */
|
/* Initialize our border blocks, and the first edge. */
|
if (reverse)
|
if (reverse)
|
{
|
{
|
ei = ei_start (bb->preds);
|
ei = ei_start (bb->preds);
|
en_block = EXIT_BLOCK_PTR;
|
en_block = EXIT_BLOCK_PTR;
|
ex_block = ENTRY_BLOCK_PTR;
|
ex_block = ENTRY_BLOCK_PTR;
|
}
|
}
|
else
|
else
|
{
|
{
|
ei = ei_start (bb->succs);
|
ei = ei_start (bb->succs);
|
en_block = ENTRY_BLOCK_PTR;
|
en_block = ENTRY_BLOCK_PTR;
|
ex_block = EXIT_BLOCK_PTR;
|
ex_block = EXIT_BLOCK_PTR;
|
}
|
}
|
|
|
/* When the stack is empty we break out of this loop. */
|
/* When the stack is empty we break out of this loop. */
|
while (1)
|
while (1)
|
{
|
{
|
basic_block bn;
|
basic_block bn;
|
|
|
/* This loop traverses edges e in depth first manner, and fills the
|
/* This loop traverses edges e in depth first manner, and fills the
|
stack. */
|
stack. */
|
while (!ei_end_p (ei))
|
while (!ei_end_p (ei))
|
{
|
{
|
e = ei_edge (ei);
|
e = ei_edge (ei);
|
|
|
/* Deduce from E the current and the next block (BB and BN), and the
|
/* Deduce from E the current and the next block (BB and BN), and the
|
next edge. */
|
next edge. */
|
if (reverse)
|
if (reverse)
|
{
|
{
|
bn = e->src;
|
bn = e->src;
|
|
|
/* If the next node BN is either already visited or a border
|
/* If the next node BN is either already visited or a border
|
block the current edge is useless, and simply overwritten
|
block the current edge is useless, and simply overwritten
|
with the next edge out of the current node. */
|
with the next edge out of the current node. */
|
if (bn == ex_block || di->dfs_order[bn->index])
|
if (bn == ex_block || di->dfs_order[bn->index])
|
{
|
{
|
ei_next (&ei);
|
ei_next (&ei);
|
continue;
|
continue;
|
}
|
}
|
bb = e->dest;
|
bb = e->dest;
|
einext = ei_start (bn->preds);
|
einext = ei_start (bn->preds);
|
}
|
}
|
else
|
else
|
{
|
{
|
bn = e->dest;
|
bn = e->dest;
|
if (bn == ex_block || di->dfs_order[bn->index])
|
if (bn == ex_block || di->dfs_order[bn->index])
|
{
|
{
|
ei_next (&ei);
|
ei_next (&ei);
|
continue;
|
continue;
|
}
|
}
|
bb = e->src;
|
bb = e->src;
|
einext = ei_start (bn->succs);
|
einext = ei_start (bn->succs);
|
}
|
}
|
|
|
gcc_assert (bn != en_block);
|
gcc_assert (bn != en_block);
|
|
|
/* Fill the DFS tree info calculatable _before_ recursing. */
|
/* Fill the DFS tree info calculatable _before_ recursing. */
|
if (bb != en_block)
|
if (bb != en_block)
|
my_i = di->dfs_order[bb->index];
|
my_i = di->dfs_order[bb->index];
|
else
|
else
|
my_i = di->dfs_order[last_basic_block];
|
my_i = di->dfs_order[last_basic_block];
|
child_i = di->dfs_order[bn->index] = di->dfsnum++;
|
child_i = di->dfs_order[bn->index] = di->dfsnum++;
|
di->dfs_to_bb[child_i] = bn;
|
di->dfs_to_bb[child_i] = bn;
|
di->dfs_parent[child_i] = my_i;
|
di->dfs_parent[child_i] = my_i;
|
|
|
/* Save the current point in the CFG on the stack, and recurse. */
|
/* Save the current point in the CFG on the stack, and recurse. */
|
stack[sp++] = ei;
|
stack[sp++] = ei;
|
ei = einext;
|
ei = einext;
|
}
|
}
|
|
|
if (!sp)
|
if (!sp)
|
break;
|
break;
|
ei = stack[--sp];
|
ei = stack[--sp];
|
|
|
/* OK. The edge-list was exhausted, meaning normally we would
|
/* OK. The edge-list was exhausted, meaning normally we would
|
end the recursion. After returning from the recursive call,
|
end the recursion. After returning from the recursive call,
|
there were (may be) other statements which were run after a
|
there were (may be) other statements which were run after a
|
child node was completely considered by DFS. Here is the
|
child node was completely considered by DFS. Here is the
|
point to do it in the non-recursive variant.
|
point to do it in the non-recursive variant.
|
E.g. The block just completed is in e->dest for forward DFS,
|
E.g. The block just completed is in e->dest for forward DFS,
|
the block not yet completed (the parent of the one above)
|
the block not yet completed (the parent of the one above)
|
in e->src. This could be used e.g. for computing the number of
|
in e->src. This could be used e.g. for computing the number of
|
descendants or the tree depth. */
|
descendants or the tree depth. */
|
ei_next (&ei);
|
ei_next (&ei);
|
}
|
}
|
free (stack);
|
free (stack);
|
}
|
}
|
|
|
/* The main entry for calculating the DFS tree or forest. DI is our working
|
/* The main entry for calculating the DFS tree or forest. DI is our working
|
structure and REVERSE is true, if we are interested in the reverse flow
|
structure and REVERSE is true, if we are interested in the reverse flow
|
graph. In that case the result is not necessarily a tree but a forest,
|
graph. In that case the result is not necessarily a tree but a forest,
|
because there may be nodes from which the EXIT_BLOCK is unreachable. */
|
because there may be nodes from which the EXIT_BLOCK is unreachable. */
|
|
|
static void
|
static void
|
calc_dfs_tree (struct dom_info *di, enum cdi_direction reverse)
|
calc_dfs_tree (struct dom_info *di, enum cdi_direction reverse)
|
{
|
{
|
/* The first block is the ENTRY_BLOCK (or EXIT_BLOCK if REVERSE). */
|
/* The first block is the ENTRY_BLOCK (or EXIT_BLOCK if REVERSE). */
|
basic_block begin = reverse ? EXIT_BLOCK_PTR : ENTRY_BLOCK_PTR;
|
basic_block begin = reverse ? EXIT_BLOCK_PTR : ENTRY_BLOCK_PTR;
|
di->dfs_order[last_basic_block] = di->dfsnum;
|
di->dfs_order[last_basic_block] = di->dfsnum;
|
di->dfs_to_bb[di->dfsnum] = begin;
|
di->dfs_to_bb[di->dfsnum] = begin;
|
di->dfsnum++;
|
di->dfsnum++;
|
|
|
calc_dfs_tree_nonrec (di, begin, reverse);
|
calc_dfs_tree_nonrec (di, begin, reverse);
|
|
|
if (reverse)
|
if (reverse)
|
{
|
{
|
/* In the post-dom case we may have nodes without a path to EXIT_BLOCK.
|
/* In the post-dom case we may have nodes without a path to EXIT_BLOCK.
|
They are reverse-unreachable. In the dom-case we disallow such
|
They are reverse-unreachable. In the dom-case we disallow such
|
nodes, but in post-dom we have to deal with them.
|
nodes, but in post-dom we have to deal with them.
|
|
|
There are two situations in which this occurs. First, noreturn
|
There are two situations in which this occurs. First, noreturn
|
functions. Second, infinite loops. In the first case we need to
|
functions. Second, infinite loops. In the first case we need to
|
pretend that there is an edge to the exit block. In the second
|
pretend that there is an edge to the exit block. In the second
|
case, we wind up with a forest. We need to process all noreturn
|
case, we wind up with a forest. We need to process all noreturn
|
blocks before we know if we've got any infinite loops. */
|
blocks before we know if we've got any infinite loops. */
|
|
|
basic_block b;
|
basic_block b;
|
bool saw_unconnected = false;
|
bool saw_unconnected = false;
|
|
|
FOR_EACH_BB_REVERSE (b)
|
FOR_EACH_BB_REVERSE (b)
|
{
|
{
|
if (EDGE_COUNT (b->succs) > 0)
|
if (EDGE_COUNT (b->succs) > 0)
|
{
|
{
|
if (di->dfs_order[b->index] == 0)
|
if (di->dfs_order[b->index] == 0)
|
saw_unconnected = true;
|
saw_unconnected = true;
|
continue;
|
continue;
|
}
|
}
|
bitmap_set_bit (di->fake_exit_edge, b->index);
|
bitmap_set_bit (di->fake_exit_edge, b->index);
|
di->dfs_order[b->index] = di->dfsnum;
|
di->dfs_order[b->index] = di->dfsnum;
|
di->dfs_to_bb[di->dfsnum] = b;
|
di->dfs_to_bb[di->dfsnum] = b;
|
di->dfs_parent[di->dfsnum] = di->dfs_order[last_basic_block];
|
di->dfs_parent[di->dfsnum] = di->dfs_order[last_basic_block];
|
di->dfsnum++;
|
di->dfsnum++;
|
calc_dfs_tree_nonrec (di, b, reverse);
|
calc_dfs_tree_nonrec (di, b, reverse);
|
}
|
}
|
|
|
if (saw_unconnected)
|
if (saw_unconnected)
|
{
|
{
|
FOR_EACH_BB_REVERSE (b)
|
FOR_EACH_BB_REVERSE (b)
|
{
|
{
|
if (di->dfs_order[b->index])
|
if (di->dfs_order[b->index])
|
continue;
|
continue;
|
bitmap_set_bit (di->fake_exit_edge, b->index);
|
bitmap_set_bit (di->fake_exit_edge, b->index);
|
di->dfs_order[b->index] = di->dfsnum;
|
di->dfs_order[b->index] = di->dfsnum;
|
di->dfs_to_bb[di->dfsnum] = b;
|
di->dfs_to_bb[di->dfsnum] = b;
|
di->dfs_parent[di->dfsnum] = di->dfs_order[last_basic_block];
|
di->dfs_parent[di->dfsnum] = di->dfs_order[last_basic_block];
|
di->dfsnum++;
|
di->dfsnum++;
|
calc_dfs_tree_nonrec (di, b, reverse);
|
calc_dfs_tree_nonrec (di, b, reverse);
|
}
|
}
|
}
|
}
|
}
|
}
|
|
|
di->nodes = di->dfsnum - 1;
|
di->nodes = di->dfsnum - 1;
|
|
|
/* This aborts e.g. when there is _no_ path from ENTRY to EXIT at all. */
|
/* This aborts e.g. when there is _no_ path from ENTRY to EXIT at all. */
|
gcc_assert (di->nodes == (unsigned int) n_basic_blocks - 1);
|
gcc_assert (di->nodes == (unsigned int) n_basic_blocks - 1);
|
}
|
}
|
|
|
/* Compress the path from V to the root of its set and update path_min at the
|
/* Compress the path from V to the root of its set and update path_min at the
|
same time. After compress(di, V) set_chain[V] is the root of the set V is
|
same time. After compress(di, V) set_chain[V] is the root of the set V is
|
in and path_min[V] is the node with the smallest key[] value on the path
|
in and path_min[V] is the node with the smallest key[] value on the path
|
from V to that root. */
|
from V to that root. */
|
|
|
static void
|
static void
|
compress (struct dom_info *di, TBB v)
|
compress (struct dom_info *di, TBB v)
|
{
|
{
|
/* Btw. It's not worth to unrecurse compress() as the depth is usually not
|
/* Btw. It's not worth to unrecurse compress() as the depth is usually not
|
greater than 5 even for huge graphs (I've not seen call depth > 4).
|
greater than 5 even for huge graphs (I've not seen call depth > 4).
|
Also performance wise compress() ranges _far_ behind eval(). */
|
Also performance wise compress() ranges _far_ behind eval(). */
|
TBB parent = di->set_chain[v];
|
TBB parent = di->set_chain[v];
|
if (di->set_chain[parent])
|
if (di->set_chain[parent])
|
{
|
{
|
compress (di, parent);
|
compress (di, parent);
|
if (di->key[di->path_min[parent]] < di->key[di->path_min[v]])
|
if (di->key[di->path_min[parent]] < di->key[di->path_min[v]])
|
di->path_min[v] = di->path_min[parent];
|
di->path_min[v] = di->path_min[parent];
|
di->set_chain[v] = di->set_chain[parent];
|
di->set_chain[v] = di->set_chain[parent];
|
}
|
}
|
}
|
}
|
|
|
/* Compress the path from V to the set root of V if needed (when the root has
|
/* Compress the path from V to the set root of V if needed (when the root has
|
changed since the last call). Returns the node with the smallest key[]
|
changed since the last call). Returns the node with the smallest key[]
|
value on the path from V to the root. */
|
value on the path from V to the root. */
|
|
|
static inline TBB
|
static inline TBB
|
eval (struct dom_info *di, TBB v)
|
eval (struct dom_info *di, TBB v)
|
{
|
{
|
/* The representant of the set V is in, also called root (as the set
|
/* The representant of the set V is in, also called root (as the set
|
representation is a tree). */
|
representation is a tree). */
|
TBB rep = di->set_chain[v];
|
TBB rep = di->set_chain[v];
|
|
|
/* V itself is the root. */
|
/* V itself is the root. */
|
if (!rep)
|
if (!rep)
|
return di->path_min[v];
|
return di->path_min[v];
|
|
|
/* Compress only if necessary. */
|
/* Compress only if necessary. */
|
if (di->set_chain[rep])
|
if (di->set_chain[rep])
|
{
|
{
|
compress (di, v);
|
compress (di, v);
|
rep = di->set_chain[v];
|
rep = di->set_chain[v];
|
}
|
}
|
|
|
if (di->key[di->path_min[rep]] >= di->key[di->path_min[v]])
|
if (di->key[di->path_min[rep]] >= di->key[di->path_min[v]])
|
return di->path_min[v];
|
return di->path_min[v];
|
else
|
else
|
return di->path_min[rep];
|
return di->path_min[rep];
|
}
|
}
|
|
|
/* This essentially merges the two sets of V and W, giving a single set with
|
/* This essentially merges the two sets of V and W, giving a single set with
|
the new root V. The internal representation of these disjoint sets is a
|
the new root V. The internal representation of these disjoint sets is a
|
balanced tree. Currently link(V,W) is only used with V being the parent
|
balanced tree. Currently link(V,W) is only used with V being the parent
|
of W. */
|
of W. */
|
|
|
static void
|
static void
|
link_roots (struct dom_info *di, TBB v, TBB w)
|
link_roots (struct dom_info *di, TBB v, TBB w)
|
{
|
{
|
TBB s = w;
|
TBB s = w;
|
|
|
/* Rebalance the tree. */
|
/* Rebalance the tree. */
|
while (di->key[di->path_min[w]] < di->key[di->path_min[di->set_child[s]]])
|
while (di->key[di->path_min[w]] < di->key[di->path_min[di->set_child[s]]])
|
{
|
{
|
if (di->set_size[s] + di->set_size[di->set_child[di->set_child[s]]]
|
if (di->set_size[s] + di->set_size[di->set_child[di->set_child[s]]]
|
>= 2 * di->set_size[di->set_child[s]])
|
>= 2 * di->set_size[di->set_child[s]])
|
{
|
{
|
di->set_chain[di->set_child[s]] = s;
|
di->set_chain[di->set_child[s]] = s;
|
di->set_child[s] = di->set_child[di->set_child[s]];
|
di->set_child[s] = di->set_child[di->set_child[s]];
|
}
|
}
|
else
|
else
|
{
|
{
|
di->set_size[di->set_child[s]] = di->set_size[s];
|
di->set_size[di->set_child[s]] = di->set_size[s];
|
s = di->set_chain[s] = di->set_child[s];
|
s = di->set_chain[s] = di->set_child[s];
|
}
|
}
|
}
|
}
|
|
|
di->path_min[s] = di->path_min[w];
|
di->path_min[s] = di->path_min[w];
|
di->set_size[v] += di->set_size[w];
|
di->set_size[v] += di->set_size[w];
|
if (di->set_size[v] < 2 * di->set_size[w])
|
if (di->set_size[v] < 2 * di->set_size[w])
|
{
|
{
|
TBB tmp = s;
|
TBB tmp = s;
|
s = di->set_child[v];
|
s = di->set_child[v];
|
di->set_child[v] = tmp;
|
di->set_child[v] = tmp;
|
}
|
}
|
|
|
/* Merge all subtrees. */
|
/* Merge all subtrees. */
|
while (s)
|
while (s)
|
{
|
{
|
di->set_chain[s] = v;
|
di->set_chain[s] = v;
|
s = di->set_child[s];
|
s = di->set_child[s];
|
}
|
}
|
}
|
}
|
|
|
/* This calculates the immediate dominators (or post-dominators if REVERSE is
|
/* This calculates the immediate dominators (or post-dominators if REVERSE is
|
true). DI is our working structure and should hold the DFS forest.
|
true). DI is our working structure and should hold the DFS forest.
|
On return the immediate dominator to node V is in di->dom[V]. */
|
On return the immediate dominator to node V is in di->dom[V]. */
|
|
|
static void
|
static void
|
calc_idoms (struct dom_info *di, enum cdi_direction reverse)
|
calc_idoms (struct dom_info *di, enum cdi_direction reverse)
|
{
|
{
|
TBB v, w, k, par;
|
TBB v, w, k, par;
|
basic_block en_block;
|
basic_block en_block;
|
edge_iterator ei, einext;
|
edge_iterator ei, einext;
|
|
|
if (reverse)
|
if (reverse)
|
en_block = EXIT_BLOCK_PTR;
|
en_block = EXIT_BLOCK_PTR;
|
else
|
else
|
en_block = ENTRY_BLOCK_PTR;
|
en_block = ENTRY_BLOCK_PTR;
|
|
|
/* Go backwards in DFS order, to first look at the leafs. */
|
/* Go backwards in DFS order, to first look at the leafs. */
|
v = di->nodes;
|
v = di->nodes;
|
while (v > 1)
|
while (v > 1)
|
{
|
{
|
basic_block bb = di->dfs_to_bb[v];
|
basic_block bb = di->dfs_to_bb[v];
|
edge e;
|
edge e;
|
|
|
par = di->dfs_parent[v];
|
par = di->dfs_parent[v];
|
k = v;
|
k = v;
|
|
|
ei = (reverse) ? ei_start (bb->succs) : ei_start (bb->preds);
|
ei = (reverse) ? ei_start (bb->succs) : ei_start (bb->preds);
|
|
|
if (reverse)
|
if (reverse)
|
{
|
{
|
/* If this block has a fake edge to exit, process that first. */
|
/* If this block has a fake edge to exit, process that first. */
|
if (bitmap_bit_p (di->fake_exit_edge, bb->index))
|
if (bitmap_bit_p (di->fake_exit_edge, bb->index))
|
{
|
{
|
einext = ei;
|
einext = ei;
|
einext.index = 0;
|
einext.index = 0;
|
goto do_fake_exit_edge;
|
goto do_fake_exit_edge;
|
}
|
}
|
}
|
}
|
|
|
/* Search all direct predecessors for the smallest node with a path
|
/* Search all direct predecessors for the smallest node with a path
|
to them. That way we have the smallest node with also a path to
|
to them. That way we have the smallest node with also a path to
|
us only over nodes behind us. In effect we search for our
|
us only over nodes behind us. In effect we search for our
|
semidominator. */
|
semidominator. */
|
while (!ei_end_p (ei))
|
while (!ei_end_p (ei))
|
{
|
{
|
TBB k1;
|
TBB k1;
|
basic_block b;
|
basic_block b;
|
|
|
e = ei_edge (ei);
|
e = ei_edge (ei);
|
b = (reverse) ? e->dest : e->src;
|
b = (reverse) ? e->dest : e->src;
|
einext = ei;
|
einext = ei;
|
ei_next (&einext);
|
ei_next (&einext);
|
|
|
if (b == en_block)
|
if (b == en_block)
|
{
|
{
|
do_fake_exit_edge:
|
do_fake_exit_edge:
|
k1 = di->dfs_order[last_basic_block];
|
k1 = di->dfs_order[last_basic_block];
|
}
|
}
|
else
|
else
|
k1 = di->dfs_order[b->index];
|
k1 = di->dfs_order[b->index];
|
|
|
/* Call eval() only if really needed. If k1 is above V in DFS tree,
|
/* Call eval() only if really needed. If k1 is above V in DFS tree,
|
then we know, that eval(k1) == k1 and key[k1] == k1. */
|
then we know, that eval(k1) == k1 and key[k1] == k1. */
|
if (k1 > v)
|
if (k1 > v)
|
k1 = di->key[eval (di, k1)];
|
k1 = di->key[eval (di, k1)];
|
if (k1 < k)
|
if (k1 < k)
|
k = k1;
|
k = k1;
|
|
|
ei = einext;
|
ei = einext;
|
}
|
}
|
|
|
di->key[v] = k;
|
di->key[v] = k;
|
link_roots (di, par, v);
|
link_roots (di, par, v);
|
di->next_bucket[v] = di->bucket[k];
|
di->next_bucket[v] = di->bucket[k];
|
di->bucket[k] = v;
|
di->bucket[k] = v;
|
|
|
/* Transform semidominators into dominators. */
|
/* Transform semidominators into dominators. */
|
for (w = di->bucket[par]; w; w = di->next_bucket[w])
|
for (w = di->bucket[par]; w; w = di->next_bucket[w])
|
{
|
{
|
k = eval (di, w);
|
k = eval (di, w);
|
if (di->key[k] < di->key[w])
|
if (di->key[k] < di->key[w])
|
di->dom[w] = k;
|
di->dom[w] = k;
|
else
|
else
|
di->dom[w] = par;
|
di->dom[w] = par;
|
}
|
}
|
/* We don't need to cleanup next_bucket[]. */
|
/* We don't need to cleanup next_bucket[]. */
|
di->bucket[par] = 0;
|
di->bucket[par] = 0;
|
v--;
|
v--;
|
}
|
}
|
|
|
/* Explicitly define the dominators. */
|
/* Explicitly define the dominators. */
|
di->dom[1] = 0;
|
di->dom[1] = 0;
|
for (v = 2; v <= di->nodes; v++)
|
for (v = 2; v <= di->nodes; v++)
|
if (di->dom[v] != di->key[v])
|
if (di->dom[v] != di->key[v])
|
di->dom[v] = di->dom[di->dom[v]];
|
di->dom[v] = di->dom[di->dom[v]];
|
}
|
}
|
|
|
/* Assign dfs numbers starting from NUM to NODE and its sons. */
|
/* Assign dfs numbers starting from NUM to NODE and its sons. */
|
|
|
static void
|
static void
|
assign_dfs_numbers (struct et_node *node, int *num)
|
assign_dfs_numbers (struct et_node *node, int *num)
|
{
|
{
|
struct et_node *son;
|
struct et_node *son;
|
|
|
node->dfs_num_in = (*num)++;
|
node->dfs_num_in = (*num)++;
|
|
|
if (node->son)
|
if (node->son)
|
{
|
{
|
assign_dfs_numbers (node->son, num);
|
assign_dfs_numbers (node->son, num);
|
for (son = node->son->right; son != node->son; son = son->right)
|
for (son = node->son->right; son != node->son; son = son->right)
|
assign_dfs_numbers (son, num);
|
assign_dfs_numbers (son, num);
|
}
|
}
|
|
|
node->dfs_num_out = (*num)++;
|
node->dfs_num_out = (*num)++;
|
}
|
}
|
|
|
/* Compute the data necessary for fast resolving of dominator queries in a
|
/* Compute the data necessary for fast resolving of dominator queries in a
|
static dominator tree. */
|
static dominator tree. */
|
|
|
static void
|
static void
|
compute_dom_fast_query (enum cdi_direction dir)
|
compute_dom_fast_query (enum cdi_direction dir)
|
{
|
{
|
int num = 0;
|
int num = 0;
|
basic_block bb;
|
basic_block bb;
|
|
|
gcc_assert (dom_info_available_p (dir));
|
gcc_assert (dom_info_available_p (dir));
|
|
|
if (dom_computed[dir] == DOM_OK)
|
if (dom_computed[dir] == DOM_OK)
|
return;
|
return;
|
|
|
FOR_ALL_BB (bb)
|
FOR_ALL_BB (bb)
|
{
|
{
|
if (!bb->dom[dir]->father)
|
if (!bb->dom[dir]->father)
|
assign_dfs_numbers (bb->dom[dir], &num);
|
assign_dfs_numbers (bb->dom[dir], &num);
|
}
|
}
|
|
|
dom_computed[dir] = DOM_OK;
|
dom_computed[dir] = DOM_OK;
|
}
|
}
|
|
|
/* The main entry point into this module. DIR is set depending on whether
|
/* The main entry point into this module. DIR is set depending on whether
|
we want to compute dominators or postdominators. */
|
we want to compute dominators or postdominators. */
|
|
|
void
|
void
|
calculate_dominance_info (enum cdi_direction dir)
|
calculate_dominance_info (enum cdi_direction dir)
|
{
|
{
|
struct dom_info di;
|
struct dom_info di;
|
basic_block b;
|
basic_block b;
|
|
|
if (dom_computed[dir] == DOM_OK)
|
if (dom_computed[dir] == DOM_OK)
|
return;
|
return;
|
|
|
timevar_push (TV_DOMINANCE);
|
timevar_push (TV_DOMINANCE);
|
if (!dom_info_available_p (dir))
|
if (!dom_info_available_p (dir))
|
{
|
{
|
gcc_assert (!n_bbs_in_dom_tree[dir]);
|
gcc_assert (!n_bbs_in_dom_tree[dir]);
|
|
|
FOR_ALL_BB (b)
|
FOR_ALL_BB (b)
|
{
|
{
|
b->dom[dir] = et_new_tree (b);
|
b->dom[dir] = et_new_tree (b);
|
}
|
}
|
n_bbs_in_dom_tree[dir] = n_basic_blocks;
|
n_bbs_in_dom_tree[dir] = n_basic_blocks;
|
|
|
init_dom_info (&di, dir);
|
init_dom_info (&di, dir);
|
calc_dfs_tree (&di, dir);
|
calc_dfs_tree (&di, dir);
|
calc_idoms (&di, dir);
|
calc_idoms (&di, dir);
|
|
|
FOR_EACH_BB (b)
|
FOR_EACH_BB (b)
|
{
|
{
|
TBB d = di.dom[di.dfs_order[b->index]];
|
TBB d = di.dom[di.dfs_order[b->index]];
|
|
|
if (di.dfs_to_bb[d])
|
if (di.dfs_to_bb[d])
|
et_set_father (b->dom[dir], di.dfs_to_bb[d]->dom[dir]);
|
et_set_father (b->dom[dir], di.dfs_to_bb[d]->dom[dir]);
|
}
|
}
|
|
|
free_dom_info (&di);
|
free_dom_info (&di);
|
dom_computed[dir] = DOM_NO_FAST_QUERY;
|
dom_computed[dir] = DOM_NO_FAST_QUERY;
|
}
|
}
|
|
|
compute_dom_fast_query (dir);
|
compute_dom_fast_query (dir);
|
|
|
timevar_pop (TV_DOMINANCE);
|
timevar_pop (TV_DOMINANCE);
|
}
|
}
|
|
|
/* Free dominance information for direction DIR. */
|
/* Free dominance information for direction DIR. */
|
void
|
void
|
free_dominance_info (enum cdi_direction dir)
|
free_dominance_info (enum cdi_direction dir)
|
{
|
{
|
basic_block bb;
|
basic_block bb;
|
|
|
if (!dom_info_available_p (dir))
|
if (!dom_info_available_p (dir))
|
return;
|
return;
|
|
|
FOR_ALL_BB (bb)
|
FOR_ALL_BB (bb)
|
{
|
{
|
et_free_tree_force (bb->dom[dir]);
|
et_free_tree_force (bb->dom[dir]);
|
bb->dom[dir] = NULL;
|
bb->dom[dir] = NULL;
|
}
|
}
|
et_free_pools ();
|
et_free_pools ();
|
|
|
n_bbs_in_dom_tree[dir] = 0;
|
n_bbs_in_dom_tree[dir] = 0;
|
|
|
dom_computed[dir] = DOM_NONE;
|
dom_computed[dir] = DOM_NONE;
|
}
|
}
|
|
|
/* Return the immediate dominator of basic block BB. */
|
/* Return the immediate dominator of basic block BB. */
|
basic_block
|
basic_block
|
get_immediate_dominator (enum cdi_direction dir, basic_block bb)
|
get_immediate_dominator (enum cdi_direction dir, basic_block bb)
|
{
|
{
|
struct et_node *node = bb->dom[dir];
|
struct et_node *node = bb->dom[dir];
|
|
|
gcc_assert (dom_computed[dir]);
|
gcc_assert (dom_computed[dir]);
|
|
|
if (!node->father)
|
if (!node->father)
|
return NULL;
|
return NULL;
|
|
|
return node->father->data;
|
return node->father->data;
|
}
|
}
|
|
|
/* Set the immediate dominator of the block possibly removing
|
/* Set the immediate dominator of the block possibly removing
|
existing edge. NULL can be used to remove any edge. */
|
existing edge. NULL can be used to remove any edge. */
|
inline void
|
inline void
|
set_immediate_dominator (enum cdi_direction dir, basic_block bb,
|
set_immediate_dominator (enum cdi_direction dir, basic_block bb,
|
basic_block dominated_by)
|
basic_block dominated_by)
|
{
|
{
|
struct et_node *node = bb->dom[dir];
|
struct et_node *node = bb->dom[dir];
|
|
|
gcc_assert (dom_computed[dir]);
|
gcc_assert (dom_computed[dir]);
|
|
|
if (node->father)
|
if (node->father)
|
{
|
{
|
if (node->father->data == dominated_by)
|
if (node->father->data == dominated_by)
|
return;
|
return;
|
et_split (node);
|
et_split (node);
|
}
|
}
|
|
|
if (dominated_by)
|
if (dominated_by)
|
et_set_father (node, dominated_by->dom[dir]);
|
et_set_father (node, dominated_by->dom[dir]);
|
|
|
if (dom_computed[dir] == DOM_OK)
|
if (dom_computed[dir] == DOM_OK)
|
dom_computed[dir] = DOM_NO_FAST_QUERY;
|
dom_computed[dir] = DOM_NO_FAST_QUERY;
|
}
|
}
|
|
|
/* Store all basic blocks immediately dominated by BB into BBS and return
|
/* Store all basic blocks immediately dominated by BB into BBS and return
|
their number. */
|
their number. */
|
int
|
int
|
get_dominated_by (enum cdi_direction dir, basic_block bb, basic_block **bbs)
|
get_dominated_by (enum cdi_direction dir, basic_block bb, basic_block **bbs)
|
{
|
{
|
int n;
|
int n;
|
struct et_node *node = bb->dom[dir], *son = node->son, *ason;
|
struct et_node *node = bb->dom[dir], *son = node->son, *ason;
|
|
|
gcc_assert (dom_computed[dir]);
|
gcc_assert (dom_computed[dir]);
|
|
|
if (!son)
|
if (!son)
|
{
|
{
|
*bbs = NULL;
|
*bbs = NULL;
|
return 0;
|
return 0;
|
}
|
}
|
|
|
for (ason = son->right, n = 1; ason != son; ason = ason->right)
|
for (ason = son->right, n = 1; ason != son; ason = ason->right)
|
n++;
|
n++;
|
|
|
*bbs = XNEWVEC (basic_block, n);
|
*bbs = XNEWVEC (basic_block, n);
|
(*bbs)[0] = son->data;
|
(*bbs)[0] = son->data;
|
for (ason = son->right, n = 1; ason != son; ason = ason->right)
|
for (ason = son->right, n = 1; ason != son; ason = ason->right)
|
(*bbs)[n++] = ason->data;
|
(*bbs)[n++] = ason->data;
|
|
|
return n;
|
return n;
|
}
|
}
|
|
|
/* Find all basic blocks that are immediately dominated (in direction DIR)
|
/* Find all basic blocks that are immediately dominated (in direction DIR)
|
by some block between N_REGION ones stored in REGION, except for blocks
|
by some block between N_REGION ones stored in REGION, except for blocks
|
in the REGION itself. The found blocks are stored to DOMS and their number
|
in the REGION itself. The found blocks are stored to DOMS and their number
|
is returned. */
|
is returned. */
|
|
|
unsigned
|
unsigned
|
get_dominated_by_region (enum cdi_direction dir, basic_block *region,
|
get_dominated_by_region (enum cdi_direction dir, basic_block *region,
|
unsigned n_region, basic_block *doms)
|
unsigned n_region, basic_block *doms)
|
{
|
{
|
unsigned n_doms = 0, i;
|
unsigned n_doms = 0, i;
|
basic_block dom;
|
basic_block dom;
|
|
|
for (i = 0; i < n_region; i++)
|
for (i = 0; i < n_region; i++)
|
region[i]->flags |= BB_DUPLICATED;
|
region[i]->flags |= BB_DUPLICATED;
|
for (i = 0; i < n_region; i++)
|
for (i = 0; i < n_region; i++)
|
for (dom = first_dom_son (dir, region[i]);
|
for (dom = first_dom_son (dir, region[i]);
|
dom;
|
dom;
|
dom = next_dom_son (dir, dom))
|
dom = next_dom_son (dir, dom))
|
if (!(dom->flags & BB_DUPLICATED))
|
if (!(dom->flags & BB_DUPLICATED))
|
doms[n_doms++] = dom;
|
doms[n_doms++] = dom;
|
for (i = 0; i < n_region; i++)
|
for (i = 0; i < n_region; i++)
|
region[i]->flags &= ~BB_DUPLICATED;
|
region[i]->flags &= ~BB_DUPLICATED;
|
|
|
return n_doms;
|
return n_doms;
|
}
|
}
|
|
|
/* Redirect all edges pointing to BB to TO. */
|
/* Redirect all edges pointing to BB to TO. */
|
void
|
void
|
redirect_immediate_dominators (enum cdi_direction dir, basic_block bb,
|
redirect_immediate_dominators (enum cdi_direction dir, basic_block bb,
|
basic_block to)
|
basic_block to)
|
{
|
{
|
struct et_node *bb_node = bb->dom[dir], *to_node = to->dom[dir], *son;
|
struct et_node *bb_node = bb->dom[dir], *to_node = to->dom[dir], *son;
|
|
|
gcc_assert (dom_computed[dir]);
|
gcc_assert (dom_computed[dir]);
|
|
|
if (!bb_node->son)
|
if (!bb_node->son)
|
return;
|
return;
|
|
|
while (bb_node->son)
|
while (bb_node->son)
|
{
|
{
|
son = bb_node->son;
|
son = bb_node->son;
|
|
|
et_split (son);
|
et_split (son);
|
et_set_father (son, to_node);
|
et_set_father (son, to_node);
|
}
|
}
|
|
|
if (dom_computed[dir] == DOM_OK)
|
if (dom_computed[dir] == DOM_OK)
|
dom_computed[dir] = DOM_NO_FAST_QUERY;
|
dom_computed[dir] = DOM_NO_FAST_QUERY;
|
}
|
}
|
|
|
/* Find first basic block in the tree dominating both BB1 and BB2. */
|
/* Find first basic block in the tree dominating both BB1 and BB2. */
|
basic_block
|
basic_block
|
nearest_common_dominator (enum cdi_direction dir, basic_block bb1, basic_block bb2)
|
nearest_common_dominator (enum cdi_direction dir, basic_block bb1, basic_block bb2)
|
{
|
{
|
gcc_assert (dom_computed[dir]);
|
gcc_assert (dom_computed[dir]);
|
|
|
if (!bb1)
|
if (!bb1)
|
return bb2;
|
return bb2;
|
if (!bb2)
|
if (!bb2)
|
return bb1;
|
return bb1;
|
|
|
return et_nca (bb1->dom[dir], bb2->dom[dir])->data;
|
return et_nca (bb1->dom[dir], bb2->dom[dir])->data;
|
}
|
}
|
|
|
|
|
/* Find the nearest common dominator for the basic blocks in BLOCKS,
|
/* Find the nearest common dominator for the basic blocks in BLOCKS,
|
using dominance direction DIR. */
|
using dominance direction DIR. */
|
|
|
basic_block
|
basic_block
|
nearest_common_dominator_for_set (enum cdi_direction dir, bitmap blocks)
|
nearest_common_dominator_for_set (enum cdi_direction dir, bitmap blocks)
|
{
|
{
|
unsigned i, first;
|
unsigned i, first;
|
bitmap_iterator bi;
|
bitmap_iterator bi;
|
basic_block dom;
|
basic_block dom;
|
|
|
first = bitmap_first_set_bit (blocks);
|
first = bitmap_first_set_bit (blocks);
|
dom = BASIC_BLOCK (first);
|
dom = BASIC_BLOCK (first);
|
EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi)
|
EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi)
|
if (dom != BASIC_BLOCK (i))
|
if (dom != BASIC_BLOCK (i))
|
dom = nearest_common_dominator (dir, dom, BASIC_BLOCK (i));
|
dom = nearest_common_dominator (dir, dom, BASIC_BLOCK (i));
|
|
|
return dom;
|
return dom;
|
}
|
}
|
|
|
/* Given a dominator tree, we can determine whether one thing
|
/* Given a dominator tree, we can determine whether one thing
|
dominates another in constant time by using two DFS numbers:
|
dominates another in constant time by using two DFS numbers:
|
|
|
1. The number for when we visit a node on the way down the tree
|
1. The number for when we visit a node on the way down the tree
|
2. The number for when we visit a node on the way back up the tree
|
2. The number for when we visit a node on the way back up the tree
|
|
|
You can view these as bounds for the range of dfs numbers the
|
You can view these as bounds for the range of dfs numbers the
|
nodes in the subtree of the dominator tree rooted at that node
|
nodes in the subtree of the dominator tree rooted at that node
|
will contain.
|
will contain.
|
|
|
The dominator tree is always a simple acyclic tree, so there are
|
The dominator tree is always a simple acyclic tree, so there are
|
only three possible relations two nodes in the dominator tree have
|
only three possible relations two nodes in the dominator tree have
|
to each other:
|
to each other:
|
|
|
1. Node A is above Node B (and thus, Node A dominates node B)
|
1. Node A is above Node B (and thus, Node A dominates node B)
|
|
|
A
|
A
|
|
|
|
|
C
|
C
|
/ \
|
/ \
|
B D
|
B D
|
|
|
|
|
In the above case, DFS_Number_In of A will be <= DFS_Number_In of
|
In the above case, DFS_Number_In of A will be <= DFS_Number_In of
|
B, and DFS_Number_Out of A will be >= DFS_Number_Out of B. This is
|
B, and DFS_Number_Out of A will be >= DFS_Number_Out of B. This is
|
because we must hit A in the dominator tree *before* B on the walk
|
because we must hit A in the dominator tree *before* B on the walk
|
down, and we will hit A *after* B on the walk back up
|
down, and we will hit A *after* B on the walk back up
|
|
|
2. Node A is below node B (and thus, node B dominates node A)
|
2. Node A is below node B (and thus, node B dominates node A)
|
|
|
|
|
B
|
B
|
|
|
|
|
A
|
A
|
/ \
|
/ \
|
C D
|
C D
|
|
|
In the above case, DFS_Number_In of A will be >= DFS_Number_In of
|
In the above case, DFS_Number_In of A will be >= DFS_Number_In of
|
B, and DFS_Number_Out of A will be <= DFS_Number_Out of B.
|
B, and DFS_Number_Out of A will be <= DFS_Number_Out of B.
|
|
|
This is because we must hit A in the dominator tree *after* B on
|
This is because we must hit A in the dominator tree *after* B on
|
the walk down, and we will hit A *before* B on the walk back up
|
the walk down, and we will hit A *before* B on the walk back up
|
|
|
3. Node A and B are siblings (and thus, neither dominates the other)
|
3. Node A and B are siblings (and thus, neither dominates the other)
|
|
|
C
|
C
|
|
|
|
|
D
|
D
|
/ \
|
/ \
|
A B
|
A B
|
|
|
In the above case, DFS_Number_In of A will *always* be <=
|
In the above case, DFS_Number_In of A will *always* be <=
|
DFS_Number_In of B, and DFS_Number_Out of A will *always* be <=
|
DFS_Number_In of B, and DFS_Number_Out of A will *always* be <=
|
DFS_Number_Out of B. This is because we will always finish the dfs
|
DFS_Number_Out of B. This is because we will always finish the dfs
|
walk of one of the subtrees before the other, and thus, the dfs
|
walk of one of the subtrees before the other, and thus, the dfs
|
numbers for one subtree can't intersect with the range of dfs
|
numbers for one subtree can't intersect with the range of dfs
|
numbers for the other subtree. If you swap A and B's position in
|
numbers for the other subtree. If you swap A and B's position in
|
the dominator tree, the comparison changes direction, but the point
|
the dominator tree, the comparison changes direction, but the point
|
is that both comparisons will always go the same way if there is no
|
is that both comparisons will always go the same way if there is no
|
dominance relationship.
|
dominance relationship.
|
|
|
Thus, it is sufficient to write
|
Thus, it is sufficient to write
|
|
|
A_Dominates_B (node A, node B)
|
A_Dominates_B (node A, node B)
|
{
|
{
|
return DFS_Number_In(A) <= DFS_Number_In(B)
|
return DFS_Number_In(A) <= DFS_Number_In(B)
|
&& DFS_Number_Out (A) >= DFS_Number_Out(B);
|
&& DFS_Number_Out (A) >= DFS_Number_Out(B);
|
}
|
}
|
|
|
A_Dominated_by_B (node A, node B)
|
A_Dominated_by_B (node A, node B)
|
{
|
{
|
return DFS_Number_In(A) >= DFS_Number_In(A)
|
return DFS_Number_In(A) >= DFS_Number_In(A)
|
&& DFS_Number_Out (A) <= DFS_Number_Out(B);
|
&& DFS_Number_Out (A) <= DFS_Number_Out(B);
|
} */
|
} */
|
|
|
/* Return TRUE in case BB1 is dominated by BB2. */
|
/* Return TRUE in case BB1 is dominated by BB2. */
|
bool
|
bool
|
dominated_by_p (enum cdi_direction dir, basic_block bb1, basic_block bb2)
|
dominated_by_p (enum cdi_direction dir, basic_block bb1, basic_block bb2)
|
{
|
{
|
struct et_node *n1 = bb1->dom[dir], *n2 = bb2->dom[dir];
|
struct et_node *n1 = bb1->dom[dir], *n2 = bb2->dom[dir];
|
|
|
gcc_assert (dom_computed[dir]);
|
gcc_assert (dom_computed[dir]);
|
|
|
if (dom_computed[dir] == DOM_OK)
|
if (dom_computed[dir] == DOM_OK)
|
return (n1->dfs_num_in >= n2->dfs_num_in
|
return (n1->dfs_num_in >= n2->dfs_num_in
|
&& n1->dfs_num_out <= n2->dfs_num_out);
|
&& n1->dfs_num_out <= n2->dfs_num_out);
|
|
|
return et_below (n1, n2);
|
return et_below (n1, n2);
|
}
|
}
|
|
|
/* Returns the entry dfs number for basic block BB, in the direction DIR. */
|
/* Returns the entry dfs number for basic block BB, in the direction DIR. */
|
|
|
unsigned
|
unsigned
|
bb_dom_dfs_in (enum cdi_direction dir, basic_block bb)
|
bb_dom_dfs_in (enum cdi_direction dir, basic_block bb)
|
{
|
{
|
struct et_node *n = bb->dom[dir];
|
struct et_node *n = bb->dom[dir];
|
|
|
gcc_assert (dom_computed[dir] == DOM_OK);
|
gcc_assert (dom_computed[dir] == DOM_OK);
|
return n->dfs_num_in;
|
return n->dfs_num_in;
|
}
|
}
|
|
|
/* Returns the exit dfs number for basic block BB, in the direction DIR. */
|
/* Returns the exit dfs number for basic block BB, in the direction DIR. */
|
|
|
unsigned
|
unsigned
|
bb_dom_dfs_out (enum cdi_direction dir, basic_block bb)
|
bb_dom_dfs_out (enum cdi_direction dir, basic_block bb)
|
{
|
{
|
struct et_node *n = bb->dom[dir];
|
struct et_node *n = bb->dom[dir];
|
|
|
gcc_assert (dom_computed[dir] == DOM_OK);
|
gcc_assert (dom_computed[dir] == DOM_OK);
|
return n->dfs_num_out;
|
return n->dfs_num_out;
|
}
|
}
|
|
|
/* Verify invariants of dominator structure. */
|
/* Verify invariants of dominator structure. */
|
void
|
void
|
verify_dominators (enum cdi_direction dir)
|
verify_dominators (enum cdi_direction dir)
|
{
|
{
|
int err = 0;
|
int err = 0;
|
basic_block bb;
|
basic_block bb;
|
|
|
gcc_assert (dom_info_available_p (dir));
|
gcc_assert (dom_info_available_p (dir));
|
|
|
FOR_EACH_BB (bb)
|
FOR_EACH_BB (bb)
|
{
|
{
|
basic_block dom_bb;
|
basic_block dom_bb;
|
basic_block imm_bb;
|
basic_block imm_bb;
|
|
|
dom_bb = recount_dominator (dir, bb);
|
dom_bb = recount_dominator (dir, bb);
|
imm_bb = get_immediate_dominator (dir, bb);
|
imm_bb = get_immediate_dominator (dir, bb);
|
if (dom_bb != imm_bb)
|
if (dom_bb != imm_bb)
|
{
|
{
|
if ((dom_bb == NULL) || (imm_bb == NULL))
|
if ((dom_bb == NULL) || (imm_bb == NULL))
|
error ("dominator of %d status unknown", bb->index);
|
error ("dominator of %d status unknown", bb->index);
|
else
|
else
|
error ("dominator of %d should be %d, not %d",
|
error ("dominator of %d should be %d, not %d",
|
bb->index, dom_bb->index, imm_bb->index);
|
bb->index, dom_bb->index, imm_bb->index);
|
err = 1;
|
err = 1;
|
}
|
}
|
}
|
}
|
|
|
if (dir == CDI_DOMINATORS)
|
if (dir == CDI_DOMINATORS)
|
{
|
{
|
FOR_EACH_BB (bb)
|
FOR_EACH_BB (bb)
|
{
|
{
|
if (!dominated_by_p (dir, bb, ENTRY_BLOCK_PTR))
|
if (!dominated_by_p (dir, bb, ENTRY_BLOCK_PTR))
|
{
|
{
|
error ("ENTRY does not dominate bb %d", bb->index);
|
error ("ENTRY does not dominate bb %d", bb->index);
|
err = 1;
|
err = 1;
|
}
|
}
|
}
|
}
|
}
|
}
|
|
|
gcc_assert (!err);
|
gcc_assert (!err);
|
}
|
}
|
|
|
/* Determine immediate dominator (or postdominator, according to DIR) of BB,
|
/* Determine immediate dominator (or postdominator, according to DIR) of BB,
|
assuming that dominators of other blocks are correct. We also use it to
|
assuming that dominators of other blocks are correct. We also use it to
|
recompute the dominators in a restricted area, by iterating it until it
|
recompute the dominators in a restricted area, by iterating it until it
|
reaches a fixed point. */
|
reaches a fixed point. */
|
|
|
basic_block
|
basic_block
|
recount_dominator (enum cdi_direction dir, basic_block bb)
|
recount_dominator (enum cdi_direction dir, basic_block bb)
|
{
|
{
|
basic_block dom_bb = NULL;
|
basic_block dom_bb = NULL;
|
edge e;
|
edge e;
|
edge_iterator ei;
|
edge_iterator ei;
|
|
|
gcc_assert (dom_computed[dir]);
|
gcc_assert (dom_computed[dir]);
|
|
|
if (dir == CDI_DOMINATORS)
|
if (dir == CDI_DOMINATORS)
|
{
|
{
|
FOR_EACH_EDGE (e, ei, bb->preds)
|
FOR_EACH_EDGE (e, ei, bb->preds)
|
{
|
{
|
/* Ignore the predecessors that either are not reachable from
|
/* Ignore the predecessors that either are not reachable from
|
the entry block, or whose dominator was not determined yet. */
|
the entry block, or whose dominator was not determined yet. */
|
if (!dominated_by_p (dir, e->src, ENTRY_BLOCK_PTR))
|
if (!dominated_by_p (dir, e->src, ENTRY_BLOCK_PTR))
|
continue;
|
continue;
|
|
|
if (!dominated_by_p (dir, e->src, bb))
|
if (!dominated_by_p (dir, e->src, bb))
|
dom_bb = nearest_common_dominator (dir, dom_bb, e->src);
|
dom_bb = nearest_common_dominator (dir, dom_bb, e->src);
|
}
|
}
|
}
|
}
|
else
|
else
|
{
|
{
|
FOR_EACH_EDGE (e, ei, bb->succs)
|
FOR_EACH_EDGE (e, ei, bb->succs)
|
{
|
{
|
if (!dominated_by_p (dir, e->dest, bb))
|
if (!dominated_by_p (dir, e->dest, bb))
|
dom_bb = nearest_common_dominator (dir, dom_bb, e->dest);
|
dom_bb = nearest_common_dominator (dir, dom_bb, e->dest);
|
}
|
}
|
}
|
}
|
|
|
return dom_bb;
|
return dom_bb;
|
}
|
}
|
|
|
/* Iteratively recount dominators of BBS. The change is supposed to be local
|
/* Iteratively recount dominators of BBS. The change is supposed to be local
|
and not to grow further. */
|
and not to grow further. */
|
void
|
void
|
iterate_fix_dominators (enum cdi_direction dir, basic_block *bbs, int n)
|
iterate_fix_dominators (enum cdi_direction dir, basic_block *bbs, int n)
|
{
|
{
|
int i, changed = 1;
|
int i, changed = 1;
|
basic_block old_dom, new_dom;
|
basic_block old_dom, new_dom;
|
|
|
gcc_assert (dom_computed[dir]);
|
gcc_assert (dom_computed[dir]);
|
|
|
for (i = 0; i < n; i++)
|
for (i = 0; i < n; i++)
|
set_immediate_dominator (dir, bbs[i], NULL);
|
set_immediate_dominator (dir, bbs[i], NULL);
|
|
|
while (changed)
|
while (changed)
|
{
|
{
|
changed = 0;
|
changed = 0;
|
for (i = 0; i < n; i++)
|
for (i = 0; i < n; i++)
|
{
|
{
|
old_dom = get_immediate_dominator (dir, bbs[i]);
|
old_dom = get_immediate_dominator (dir, bbs[i]);
|
new_dom = recount_dominator (dir, bbs[i]);
|
new_dom = recount_dominator (dir, bbs[i]);
|
if (old_dom != new_dom)
|
if (old_dom != new_dom)
|
{
|
{
|
changed = 1;
|
changed = 1;
|
set_immediate_dominator (dir, bbs[i], new_dom);
|
set_immediate_dominator (dir, bbs[i], new_dom);
|
}
|
}
|
}
|
}
|
}
|
}
|
|
|
for (i = 0; i < n; i++)
|
for (i = 0; i < n; i++)
|
gcc_assert (get_immediate_dominator (dir, bbs[i]));
|
gcc_assert (get_immediate_dominator (dir, bbs[i]));
|
}
|
}
|
|
|
void
|
void
|
add_to_dominance_info (enum cdi_direction dir, basic_block bb)
|
add_to_dominance_info (enum cdi_direction dir, basic_block bb)
|
{
|
{
|
gcc_assert (dom_computed[dir]);
|
gcc_assert (dom_computed[dir]);
|
gcc_assert (!bb->dom[dir]);
|
gcc_assert (!bb->dom[dir]);
|
|
|
n_bbs_in_dom_tree[dir]++;
|
n_bbs_in_dom_tree[dir]++;
|
|
|
bb->dom[dir] = et_new_tree (bb);
|
bb->dom[dir] = et_new_tree (bb);
|
|
|
if (dom_computed[dir] == DOM_OK)
|
if (dom_computed[dir] == DOM_OK)
|
dom_computed[dir] = DOM_NO_FAST_QUERY;
|
dom_computed[dir] = DOM_NO_FAST_QUERY;
|
}
|
}
|
|
|
void
|
void
|
delete_from_dominance_info (enum cdi_direction dir, basic_block bb)
|
delete_from_dominance_info (enum cdi_direction dir, basic_block bb)
|
{
|
{
|
gcc_assert (dom_computed[dir]);
|
gcc_assert (dom_computed[dir]);
|
|
|
et_free_tree (bb->dom[dir]);
|
et_free_tree (bb->dom[dir]);
|
bb->dom[dir] = NULL;
|
bb->dom[dir] = NULL;
|
n_bbs_in_dom_tree[dir]--;
|
n_bbs_in_dom_tree[dir]--;
|
|
|
if (dom_computed[dir] == DOM_OK)
|
if (dom_computed[dir] == DOM_OK)
|
dom_computed[dir] = DOM_NO_FAST_QUERY;
|
dom_computed[dir] = DOM_NO_FAST_QUERY;
|
}
|
}
|
|
|
/* Returns the first son of BB in the dominator or postdominator tree
|
/* Returns the first son of BB in the dominator or postdominator tree
|
as determined by DIR. */
|
as determined by DIR. */
|
|
|
basic_block
|
basic_block
|
first_dom_son (enum cdi_direction dir, basic_block bb)
|
first_dom_son (enum cdi_direction dir, basic_block bb)
|
{
|
{
|
struct et_node *son = bb->dom[dir]->son;
|
struct et_node *son = bb->dom[dir]->son;
|
|
|
return son ? son->data : NULL;
|
return son ? son->data : NULL;
|
}
|
}
|
|
|
/* Returns the next dominance son after BB in the dominator or postdominator
|
/* Returns the next dominance son after BB in the dominator or postdominator
|
tree as determined by DIR, or NULL if it was the last one. */
|
tree as determined by DIR, or NULL if it was the last one. */
|
|
|
basic_block
|
basic_block
|
next_dom_son (enum cdi_direction dir, basic_block bb)
|
next_dom_son (enum cdi_direction dir, basic_block bb)
|
{
|
{
|
struct et_node *next = bb->dom[dir]->right;
|
struct et_node *next = bb->dom[dir]->right;
|
|
|
return next->father->son == next ? NULL : next->data;
|
return next->father->son == next ? NULL : next->data;
|
}
|
}
|
|
|
/* Returns true if dominance information for direction DIR is available. */
|
/* Returns true if dominance information for direction DIR is available. */
|
|
|
bool
|
bool
|
dom_info_available_p (enum cdi_direction dir)
|
dom_info_available_p (enum cdi_direction dir)
|
{
|
{
|
return dom_computed[dir] != DOM_NONE;
|
return dom_computed[dir] != DOM_NONE;
|
}
|
}
|
|
|
void
|
void
|
debug_dominance_info (enum cdi_direction dir)
|
debug_dominance_info (enum cdi_direction dir)
|
{
|
{
|
basic_block bb, bb2;
|
basic_block bb, bb2;
|
FOR_EACH_BB (bb)
|
FOR_EACH_BB (bb)
|
if ((bb2 = get_immediate_dominator (dir, bb)))
|
if ((bb2 = get_immediate_dominator (dir, bb)))
|
fprintf (stderr, "%i %i\n", bb->index, bb2->index);
|
fprintf (stderr, "%i %i\n", bb->index, bb2->index);
|
}
|
}
|
|
|
