X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fana%2Fircfscc.c;h=5b89447e9f3ad2c78349eed7abffb91bba19225c;hb=8aca33381b3dea1ef0bb6c120f59989075c438d1;hp=0e50feb66affb5b35c810b78e877b5125d758112;hpb=5a22cde84af91782200d50d55e5f990805c3e611;p=libfirm diff --git a/ir/ana/ircfscc.c b/ir/ana/ircfscc.c index 0e50feb66..5b89447e9 100644 --- a/ir/ana/ircfscc.c +++ b/ir/ana/ircfscc.c @@ -1,25 +1,19 @@ /* - * Project: libFIRM - * File name: ir/ana/irscc.c - * Purpose: Compute the strongly connected regions and build - * backedge/cfloop datastructures. - * A variation on the Tarjan algorithm. See also [Trapp:99], - * Chapter 5.2.1.2. - * Author: Goetz Lindenmaier - * Modified by: - * Created: 7.2002 - * CVS-ID: $Id$ - * Copyright: (c) 2002-2003 Universität Karlsruhe - * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE. + * This file is part of libFirm. + * Copyright (C) 2012 University of Karlsruhe. */ -#ifdef HAVE_CONFIG_H +/** + * @file + * @brief Compute the strongly connected regions and build backedge/cfloop + * datastructures. A variation on the Tarjan algorithm. See also + * [Trapp:99], Chapter 5.2.1.2. + * @author Goetz Lindenmaier + * @date 7.2002 + */ #include "config.h" -#endif -#ifdef HAVE_STRING_H #include -#endif #include "irloop_t.h" #include "irnode_t.h" @@ -29,213 +23,231 @@ #include "irgwalk.h" #include "irprog_t.h" #include "irdump.h" - -#define NO_CFLOOPS_WITHOUT_HEAD 1 - -static ir_graph *outermost_ir_graph; /* The outermost graph the scc is computed - for */ -static ir_loop *current_loop; /* Current cfloop construction is working - on. */ -static int loop_node_cnt = 0; /* Counts the number of allocated cfloop nodes. - Each cfloop node gets a unique number. - What for? ev. remove. @@@ */ -static int current_dfn = 1; /* Counter to generate depth first numbering - of visited nodes. */ - -static int max_loop_depth = 0; - -void link_to_reg_end (ir_node *n, void *env); - -/**********************************************************************/ -/* Node attributes **/ -/**********************************************************************/ +#include "ircons_t.h" + +/** The outermost graph the scc is computed for */ +static ir_graph *outermost_ir_graph; +/** Current cfloop construction is working on. */ +static ir_loop *current_loop; +/** Counts the number of allocated cfloop nodes. + * Each cfloop node gets a unique number. + * @todo What for? ev. remove. + */ +static int loop_node_cnt = 0; +/** Counter to generate depth first numbering of visited nodes. */ +static int current_dfn = 1; /**********************************************************************/ /* Node attributes needed for the construction. **/ /**********************************************************************/ +/** + * The SCC info. Additional fields for an ir-node needed for the + * construction. + */ typedef struct scc_info { - bool in_stack; /* Marks whether node is on the stack. */ - int dfn; /* Depth first search number. */ - int uplink; /* dfn number of ancestor. */ + int in_stack; /**< Marks whether node is on the stack. */ + int dfn; /**< Depth first search number. */ + int uplink; /**< dfn number of ancestor. */ } scc_info; -static INLINE scc_info* new_scc_info(void) { - scc_info *info = obstack_alloc (outermost_ir_graph->obst, sizeof (scc_info)); - memset (info, 0, sizeof (scc_info)); - return info; +/** Allocate a new scc_info on the given obstack */ +static inline scc_info *new_scc_info(struct obstack *obst) +{ + return OALLOCZ(obst, scc_info); } -static INLINE void -mark_irn_in_stack (ir_node *n) { - assert(get_irn_link(n)); - ((scc_info *)n->link)->in_stack = true; +/** + * Marks the node n to be on the stack. + */ +static inline void mark_irn_in_stack(ir_node *n) +{ + scc_info *info = (scc_info*) get_irn_link(n); + info->in_stack = 1; } -static INLINE void -mark_irn_not_in_stack (ir_node *n) { - assert(get_irn_link(n)); - ((scc_info *)n->link)->in_stack = false; +/** + * Marks the node n to be not on the stack. + */ +static inline void mark_irn_not_in_stack(ir_node *n) +{ + scc_info *info = (scc_info*) get_irn_link(n); + info->in_stack = 0; } -static INLINE bool -irn_is_in_stack (ir_node *n) { - assert(get_irn_link(n)); - return ((scc_info *)n->link)->in_stack; +/** + * Returns whether node n is on the stack. + */ +static inline int irn_is_in_stack(ir_node *n) +{ + scc_info *info = (scc_info*) get_irn_link(n); + return info->in_stack; } -static INLINE void -set_irn_uplink (ir_node *n, int uplink) { - assert(get_irn_link(n)); - ((scc_info *)n->link)->uplink = uplink; +/** + * Sets node n uplink value. + */ +static inline void set_irn_uplink(ir_node *n, int uplink) +{ + scc_info *info = (scc_info*) get_irn_link(n); + info->uplink = uplink; } -static INLINE int -get_irn_uplink (ir_node *n) { - assert(get_irn_link(n)); - return ((scc_info *)n->link)->uplink; +/** + * Return node n uplink value. + */ +static inline int get_irn_uplink(ir_node *n) +{ + scc_info *info = (scc_info*) get_irn_link(n); + return info->uplink; } -static INLINE void -set_irn_dfn (ir_node *n, int dfn) { - assert(get_irn_link(n)); - ((scc_info *)n->link)->dfn = dfn; +/** + * Sets node n dfn value. + */ +static inline void set_irn_dfn(ir_node *n, int dfn) +{ + scc_info *info = (scc_info*) get_irn_link(n); + info->dfn = dfn; } -static INLINE int -get_irn_dfn (ir_node *n) { - assert(get_irn_link(n)); - return ((scc_info *)n->link)->dfn; +/** + * Returns node n dfn value. + */ +static inline int get_irn_dfn(ir_node *n) +{ + scc_info *info = (scc_info*) get_irn_link(n); + return info->dfn; } /**********************************************************************/ /* A stack. **/ /**********************************************************************/ +/** An IR-node stack */ static ir_node **stack = NULL; -static int tos = 0; /* top of stack */ - -static INLINE void init_stack(void) { - if (stack) { - ARR_RESIZE (ir_node *, stack, 1000); - } else { - stack = NEW_ARR_F (ir_node *, 1000); - } - tos = 0; +/** The top (index) of the IR-node stack */ +static size_t tos = 0; + +/** + * Initializes the IR-node stack + */ +static inline void init_stack(void) +{ + if (stack) { + ARR_RESIZE(ir_node *, stack, 1000); + } else { + stack = NEW_ARR_F(ir_node *, 1000); + } + tos = 0; } +static void finish_stack(void) +{ + DEL_ARR_F(stack); + stack = NULL; +} -static INLINE void -push (ir_node *n) +/** + * Push a node n onto the IR-node stack. + */ +static inline void push(ir_node *n) { - if (tos == ARR_LEN (stack)) { - int nlen = ARR_LEN (stack) * 2; - ARR_RESIZE (ir_node *, stack, nlen); - } - stack [tos++] = n; - mark_irn_in_stack(n); + if (tos == ARR_LEN(stack)) { + size_t nlen = ARR_LEN(stack) * 2; + ARR_RESIZE(ir_node *, stack, nlen); + } + stack[tos++] = n; + mark_irn_in_stack(n); } -static INLINE ir_node * -pop (void) +/** + * Pop a node from the IR-node stack and return it. + */ +static inline ir_node *pop(void) { - ir_node *n = stack[--tos]; - mark_irn_not_in_stack(n); - return n; + ir_node *n = stack[--tos]; + mark_irn_not_in_stack(n); + return n; } -/* The nodes up to n belong to the current loop. - Removes them from the stack and adds them to the current loop. */ -static INLINE void -pop_scc_to_loop (ir_node *n) +/** + * The nodes from tos up to n belong to the current loop. + * Removes them from the stack and adds them to the current loop. + */ +static inline void pop_scc_to_loop(ir_node *n) { - ir_node *m; - - /*for (;;) {*/ - do { - m = pop(); - loop_node_cnt++; - set_irn_dfn(m, loop_node_cnt); - add_loop_node(current_loop, m); - set_irn_loop(m, current_loop); - /* if (m==n) break;*/ - } while(m != n); + ir_node *m; + + do { + m = pop(); + loop_node_cnt++; + set_irn_dfn(m, loop_node_cnt); + add_loop_node(current_loop, m); + set_irn_loop(m, current_loop); + } while (m != n); } /* GL ??? my last son is my grandson??? Removes cfloops with no ir_nodes in them. Such loops have only another loop as son. (Why can't they have two loops as sons? Does it never get that far? ) */ -static void close_loop (ir_loop *l) +static void close_loop(ir_loop *l) { - int last = get_loop_n_elements(l) - 1; - loop_element lelement = get_loop_element(l, last); - ir_loop *last_son = lelement.son; - - if (get_kind(last_son) == k_ir_loop && - get_loop_n_elements(last_son) == 1) { - ir_loop *gson; - - lelement = get_loop_element(last_son, 0); - gson = lelement.son; - if(get_kind(gson) == k_ir_loop) { - loop_element new_last_son; - - gson -> outer_loop = l; - new_last_son.son = gson; - l -> children[last] = new_last_son; - } - } - - current_loop = l; + size_t last = get_loop_n_elements(l) - 1; + loop_element lelement = get_loop_element(l, last); + ir_loop *last_son = lelement.son; + + if (get_kind(last_son) == k_ir_loop && + get_loop_n_elements(last_son) == 1) { + ir_loop *gson; + + lelement = get_loop_element(last_son, 0); + gson = lelement.son; + if (get_kind(gson) == k_ir_loop) { + loop_element new_last_son; + + gson->outer_loop = l; + new_last_son.son = gson; + l->children[last] = new_last_son; + + /* the loop last_son is dead now, recover at least some memory */ + DEL_ARR_F(last_son->children); + } + } + + current_loop = l; } -/* Removes and unmarks all nodes up to n from the stack. - The nodes must be visited once more to assign them to a scc. */ -static INLINE void -pop_scc_unmark_visit (ir_node *n) +/** + * Removes and unmarks all nodes up to n from the stack. + * The nodes must be visited once more to assign them to a scc. + */ +static inline void pop_scc_unmark_visit(ir_node *n) { - ir_node *m = NULL; + ir_node *m; - while (m != n) { - m = pop(); - set_irn_visited(m, 0); - } + do { + m = pop(); + set_irn_visited(m, 0); + } while (m != n); } /**********************************************************************/ /* The loop datastructure. **/ /**********************************************************************/ -/* Allocates a new loop as son of current_loop. Sets current_loop - to the new loop and returns the father. */ -static ir_loop *new_loop (void) { - ir_loop *father, *son; - - father = current_loop; - - son = (ir_loop *) obstack_alloc (outermost_ir_graph->obst, sizeof (ir_loop)); - memset (son, 0, sizeof (ir_loop)); - son->kind = k_ir_loop; - son->children = NEW_ARR_F (loop_element, 0); - son->n_nodes = 0; - son->n_sons=0; - if (father) { - son->outer_loop = father; - add_loop_son(father, son); - son->depth = father->depth+1; - if (son->depth > max_loop_depth) max_loop_depth = son->depth; - } else { /* The root loop */ - son->outer_loop = son; - son->depth = 0; - } - -#ifdef DEBUG_libfirm - son->loop_nr = get_irp_new_node_nr(); - son->link = NULL; -#endif - - current_loop = son; - return father; +/** + * Allocates a new loop as son of current_loop. Sets current_loop + * to the new loop and returns its father. + * The loop is allocated on the outermost_ir_graphs's obstack. + */ +static ir_loop *new_loop(void) +{ + ir_loop *father = current_loop; + ir_loop *son = alloc_loop(father, get_irg_obstack(outermost_ir_graph)); + + current_loop = son; + return father; } /**********************************************************************/ @@ -244,484 +256,363 @@ static ir_loop *new_loop (void) { /* Initialization steps. **********************************************/ -static INLINE void -init_node (ir_node *n, void *env) { - if (is_Block(n)) - set_irn_link (n, new_scc_info()); - clear_backedges(n); -} - -static INLINE void -init_scc_common (void) { - current_dfn = 1; - loop_node_cnt = 0; - init_stack(); +/** + * Allocates a scc_info for every Block node n. + * Clear the backedges for all nodes. + * Called from a walker. + */ +static inline void init_node(ir_node *n, void *env) +{ + struct obstack *obst = (struct obstack*) env; + if (is_Block(n)) + set_irn_link(n, new_scc_info(obst)); + clear_backedges(n); } -static INLINE void -init_scc (ir_graph *irg) { - init_scc_common(); - irg_walk_graph (irg, init_node, NULL, NULL); +/** + * Initializes the common global settings for the scc algorithm + */ +static inline void init_scc_common(void) +{ + current_dfn = 1; + loop_node_cnt = 0; + init_stack(); } -static INLINE void -init_ip_scc (void) { - init_scc_common(); - cg_walk (init_node, NULL, NULL); - -#if EXPERIMENTAL_CFLOOP_TREE - cg_walk (link_to_reg_end, NULL, NULL); -#endif +/** + * Initializes the scc algorithm for the intraprocedural case. + * Add scc info to every block node. + */ +static inline void init_scc(ir_graph *irg, struct obstack *obst) +{ + init_scc_common(); + irg_walk_graph(irg, init_node, NULL, obst); } -/* Condition for breaking the recursion. */ -static bool is_outermost_StartBlock(ir_node *n) { - /* Test whether this is the outermost Start node. If so - recursion must end. */ - assert(is_Block(n)); - if ((get_Block_n_cfgpreds(n) == 1) && - (get_irn_op(skip_Proj(get_Block_cfgpred(n, 0))) == op_Start) && - (get_nodes_block(skip_Proj(get_Block_cfgpred(n, 0))) == n)) { - return true; - } - return false; +static inline void finish_scc(void) +{ + finish_stack(); } -/** Returns true if n is a loop header, i.e., it is a Block node +/** Returns non-zero if n is a loop header, i.e., it is a Block node * and has predecessors within the cfloop and out of the cfloop. * - * @param root: only needed for assertion. + * @param n the block node to check + * @param root only needed for assertion. */ -static bool -is_head (ir_node *n, ir_node *root) +static int is_head(ir_node *n, ir_node *root) { - int i, arity; - int some_outof_loop = 0, some_in_loop = 0; - - assert(is_Block(n)); - - if (!is_outermost_StartBlock(n)) { - arity = get_irn_arity(n); - for (i = 0; i < arity; i++) { - ir_node *pred = get_nodes_block(skip_Proj(get_irn_n(n, i))); - if (is_backedge(n, i)) continue; - if (!irn_is_in_stack(pred)) { - some_outof_loop = 1; - } else { - if (get_irn_uplink(pred) < get_irn_uplink(root)) { - DDMN(pred); DDMN(root); - assert(get_irn_uplink(pred) >= get_irn_uplink(root)); + int some_outof_loop = 0, some_in_loop = 0; + (void) root; + + int const arity = get_Block_n_cfgpreds(n); + for (int i = 0; i < arity; i++) { + ir_node *pred = get_Block_cfgpred_block(n, i); + /* ignore Bad control flow: it cannot happen */ + if (is_Bad(pred)) + continue; + if (is_backedge(n, i)) + continue; + if (!irn_is_in_stack(pred)) { + some_outof_loop = 1; + } else { + assert(get_irn_uplink(pred) >= get_irn_uplink(root)); + some_in_loop = 1; + } } - some_in_loop = 1; - } - } - } - return some_outof_loop && some_in_loop; + return some_outof_loop & some_in_loop; } -/* Returns true if n is possible loop head of an endless loop. - I.e., it is a Block, Phi or Filter node and has only predecessors - within the loop. - @arg root: only needed for assertion. */ -static bool -is_endless_head (ir_node *n, ir_node *root) +/** + * Returns non-zero if n is possible loop head of an endless loop. + * I.e., it is a Block node and has only predecessors + * within the loop. + * + * @param n the block node to check + * @param root only needed for assertion. + */ +static int is_endless_head(ir_node *n, ir_node *root) { - int i, arity; - int some_outof_loop = 0, some_in_loop = 0; - - assert(is_Block(n)); - /* Test for legal loop header: Block, Phi, ... */ - if (!is_outermost_StartBlock(n)) { - arity = get_irn_arity(n); - for (i = 0; i < arity; i++) { - ir_node *pred = get_nodes_block(skip_Proj(get_irn_n(n, i))); - assert(pred); - if (is_backedge(n, i)) { continue; } - if (!irn_is_in_stack(pred)) { - some_outof_loop = 1; //printf(" some out of loop "); - } else { - if(get_irn_uplink(pred) < get_irn_uplink(root)) { - DDMN(pred); DDMN(root); - assert(get_irn_uplink(pred) >= get_irn_uplink(root)); + int none_outof_loop = 1, some_in_loop = 0; + (void) root; + + /* Test for legal loop header: Block, Phi, ... */ + int const arity = get_Block_n_cfgpreds(n); + for (int i = 0; i < arity; i++) { + ir_node *pred = get_Block_cfgpred_block(n, i); + /* ignore Bad control flow: it cannot happen */ + if (is_Bad(pred)) + continue; + if (is_backedge(n, i)) + continue; + if (!irn_is_in_stack(pred)) { + none_outof_loop = 0; + } else { + assert(get_irn_uplink(pred) >= get_irn_uplink(root)); + some_in_loop = 1; + } } - some_in_loop = 1; - } - } - } - return !some_outof_loop && some_in_loop; + return none_outof_loop && some_in_loop; } -/* Returns index of the predecessor with the smallest dfn number - greater-equal than limit. */ -static int -smallest_dfn_pred (ir_node *n, int limit) +/** + * Returns index of the predecessor with the smallest dfn number + * greater-equal than limit. + */ +static int smallest_dfn_pred(ir_node *n, int limit) { - int i, index = -2, min = -1; - - if (!is_outermost_StartBlock(n)) { - int arity = get_irn_arity(n); - for (i = 0; i < arity; i++) { - ir_node *pred = get_nodes_block(skip_Proj(get_irn_n(n, i))); - if (is_backedge(n, i) || !irn_is_in_stack(pred)) continue; - if (get_irn_dfn(pred) >= limit && (min == -1 || get_irn_dfn(pred) < min)) { - index = i; - min = get_irn_dfn(pred); - } - } - } - return index; + int i, index = -2, min = -1; + + int arity = get_Block_n_cfgpreds(n); + for (i = 0; i < arity; i++) { + ir_node *pred = get_Block_cfgpred_block(n, i); + /* ignore Bad control flow: it cannot happen */ + if (is_Bad(pred)) + continue; + if (is_backedge(n, i) || !irn_is_in_stack(pred)) + continue; + if (get_irn_dfn(pred) >= limit && (min == -1 || get_irn_dfn(pred) < min)) { + index = i; + min = get_irn_dfn(pred); + } + } + return index; } -/* Returns index of the predecessor with the largest dfn number. */ -static int -largest_dfn_pred (ir_node *n) +/** + * Returns index of the predecessor with the largest dfn number. + */ +static int largest_dfn_pred(ir_node *n) { - int i, index = -2, max = -1; - - if (!is_outermost_StartBlock(n)) { - int arity = get_irn_arity(n); - for (i = 0; i < arity; i++) { - ir_node *pred = get_nodes_block(skip_Proj(get_irn_n(n, i))); - if (is_backedge (n, i) || !irn_is_in_stack(pred)) continue; - if (get_irn_dfn(pred) > max) { - index = i; - max = get_irn_dfn(pred); - } - } - } - return index; -} - -/* Searches the stack for possible loop heads. Tests these for backedges. - If it finds a head with an unmarked backedge it marks this edge and - returns the tail of the loop. - If it finds no backedge returns NULL. */ -static ir_node * -find_tail (ir_node *n) { - ir_node *m; - int i, res_index = -2; - - m = stack[tos-1]; /* tos = top of stack */ - if (is_head (m, n)) { - res_index = smallest_dfn_pred(m, 0); - if ((res_index == -2) && /* no smallest dfn pred found. */ - (n == m)) - return NULL; - } else { - if (m == n) return NULL; - for (i = tos-2; i >= 0; --i) { - - m = stack[i]; - if (is_head (m, n)) { - res_index = smallest_dfn_pred (m, get_irn_dfn(m) + 1); - if (res_index == -2) /* no smallest dfn pred found. */ - res_index = largest_dfn_pred (m); - - if ((m == n) && (res_index == -2)) { - i = -1; + int i, index = -2, max = -1; + + int arity = get_Block_n_cfgpreds(n); + for (i = 0; i < arity; i++) { + ir_node *pred = get_Block_cfgpred_block(n, i); + /* ignore Bad control flow: it cannot happen */ + if (is_Bad(pred)) + continue; + if (is_backedge(n, i) || !irn_is_in_stack(pred)) + continue; + if (get_irn_dfn(pred) > max) { + index = i; + max = get_irn_dfn(pred); + } } - break; - } - - - /* We should not walk past our selves on the stack: The upcoming nodes - are not in this loop. We assume a loop not reachable from Start. */ - if (m == n) { - i = -1; - break; - } - - } - + return index; +} - if (i < 0) { - /* A dead loop not reachable from Start. */ - for (i = tos-2; i >= 0; --i) { - m = stack[i]; - if (is_endless_head (m, n)) { - res_index = smallest_dfn_pred (m, get_irn_dfn(m) + 1); - if (res_index == -2) /* no smallest dfn pred found. */ - res_index = largest_dfn_pred (m); - break; +/** + * Searches the stack for possible loop heads. Tests these for backedges. + * If it finds a head with an unmarked backedge it marks this edge and + * returns the tail of the loop. + * If it finds no backedge returns NULL. + */ +static ir_node *find_tail(ir_node *n) +{ + ir_node *m; + int res_index = -2; + size_t i; + + m = stack[tos - 1]; /* tos = top of stack */ + if (is_head(m, n)) { + res_index = smallest_dfn_pred(m, 0); + if ((res_index == -2) && /* no smallest dfn pred found. */ + (n == m)) + return NULL; + } else { + if (m == n) + return NULL; + for (i = tos - 1; i != 0;) { + m = stack[--i]; + if (is_head(m, n)) { + res_index = smallest_dfn_pred(m, get_irn_dfn(m) + 1); + if (res_index == -2) /* no smallest dfn pred found. */ + res_index = largest_dfn_pred(m); + + if ((m == n) && (res_index == -2)) { + i = (size_t)-1; + } + break; + } + + + /* We should not walk past our selves on the stack: The upcoming nodes + are not in this loop. We assume a loop not reachable from Start. */ + if (m == n) { + i = (size_t)-1; + break; + } + } + + if (i == (size_t)-1) { + /* A dead loop not reachable from Start. */ + for (i = tos - 1; i != 0;) { + m = stack[--i]; + if (is_endless_head(m, n)) { + res_index = smallest_dfn_pred (m, get_irn_dfn(m) + 1); + if (res_index == -2) /* no smallest dfn pred found. */ + res_index = largest_dfn_pred(m); + break; + } + if (m == n) break; /* It's not an unreachable loop, either. */ + } + //assert(0 && "no head found on stack"); + } } - if (m == n) { break; } /* It's not an unreachable loop, either. */ - } - //assert(0 && "no head found on stack"); - } + assert(res_index > -2); - } - assert (res_index > -2); - - set_backedge (m, res_index); - return is_outermost_StartBlock(n) ? NULL : get_nodes_block(skip_Proj(get_irn_n(m, res_index))); + set_backedge(m, res_index); + return get_Block_cfgpred_block(m, res_index); } -INLINE static int -is_outermost_loop(ir_loop *l) { - return l == get_loop_outer_loop(l); +/** + * returns non.zero if l is the outermost loop. + */ +inline static int is_outermost_loop(ir_loop *l) +{ + return l == get_loop_outer_loop(l); } /*-----------------------------------------------------------* * The core algorithm. * *-----------------------------------------------------------*/ +/** + * Walks over all blocks of a graph + */ +static void cfscc(ir_node *n) +{ + int arity; + int i; + + assert(is_Block(n)); + + if (irn_visited_else_mark(n)) return; + + /* Initialize the node */ + set_irn_dfn(n, current_dfn); /* Depth first number for this node */ + set_irn_uplink(n, current_dfn); /* ... is default uplink. */ + set_irn_loop(n, NULL); + ++current_dfn; + push(n); + + arity = get_Block_n_cfgpreds(n); + + for (i = 0; i < arity; i++) { + ir_node *m; + + if (is_backedge(n, i)) + continue; + m = get_Block_cfgpred_block(n, i); + /* ignore Bad control flow: it cannot happen */ + if (is_Bad(m)) + continue; + + cfscc(m); + if (irn_is_in_stack(m)) { + /* Uplink of m is smaller if n->m is a backedge. + Propagate the uplink to mark the cfloop. */ + if (get_irn_uplink(m) < get_irn_uplink(n)) + set_irn_uplink(n, get_irn_uplink(m)); + } + } -static void cfscc (ir_node *n) { - int i; - - assert(is_Block(n)); - - if (irn_visited(n)) return; - mark_irn_visited(n); - - /* Initialize the node */ - set_irn_dfn(n, current_dfn); /* Depth first number for this node */ - set_irn_uplink(n, current_dfn); /* ... is default uplink. */ - set_irn_loop(n, NULL); - current_dfn ++; - push(n); - - /* AS: get_start_index might return -1 for Control Flow Nodes, and thus a negative - array index would be passed to is_backedge(). But CFG Nodes dont't have a backedge array, - so is_backedge does not access array[-1] but correctly returns false! */ - - if (!is_outermost_StartBlock(n)) { - int arity = get_irn_arity(n); - - for (i = 0; i < arity; i++) { - ir_node *m; - if (is_backedge(n, i)) continue; - m = get_nodes_block(skip_Proj(get_irn_n(n, i))); - - cfscc (m); - if (irn_is_in_stack(m)) { - /* Uplink of m is smaller if n->m is a backedge. - Propagate the uplink to mark the cfloop. */ - if (get_irn_uplink(m) < get_irn_uplink(n)) - set_irn_uplink(n, get_irn_uplink(m)); - } - } - } - - if (get_irn_dfn(n) == get_irn_uplink(n)) { - /* This condition holds for - 1) the node with the incoming backedge. - That is: We found a cfloop! - 2) Straight line code, because no uplink has been propagated, so the - uplink still is the same as the dfn. - - But n might not be a proper cfloop head for the analysis. Proper cfloop - heads are Block and Phi nodes. find_tail searches the stack for - Block's and Phi's and takes those nodes as cfloop heads for the current - cfloop instead and marks the incoming edge as backedge. */ - - ir_node *tail = find_tail(n); - if (tail) { - /* We have a cfloop, that is no straight line code, - because we found a cfloop head! - Next actions: Open a new cfloop on the cfloop tree and - try to find inner cfloops */ - -#if NO_CFLOOPS_WITHOUT_HEAD - - /* This is an adaption of the algorithm from fiasco / optscc to - * avoid cfloops without Block or Phi as first node. This should - * severely reduce the number of evaluations of nodes to detect - * a fixpoint in the heap analysis. - * Further it avoids cfloops without firm nodes that cause errors - * in the heap analyses. */ - - ir_loop *l; - int close; - if ((get_loop_n_elements(current_loop) > 0) || (is_outermost_loop(current_loop))) { - l = new_loop(); - close = 1; - } else { - l = current_loop; - close = 0; - } - -#else - - ir_loop *l = new_loop(); - -#endif - - /* Remove the cfloop from the stack ... */ - pop_scc_unmark_visit (n); - - /* The current backedge has been marked, that is temporarily eliminated, - by find tail. Start the scc algorithm - anew on the subgraph thats left (the current cfloop without the backedge) - in order to find more inner cfloops. */ - - cfscc (tail); - - assert (irn_visited(n)); -#if NO_CFLOOPS_WITHOUT_HEAD - if (close) -#endif - close_loop(l); - } - else - { - /* AS: No cfloop head was found, that is we have straightline code. - Pop all nodes from the stack to the current cfloop. */ - pop_scc_to_loop(n); - } - } -} - -/* Constructs backedge information for irg. */ -int construct_cf_backedges(ir_graph *irg) { - ir_graph *rem = current_ir_graph; - ir_loop *head_rem; - ir_node *end = get_irg_end(irg); - int i; - - assert(!get_interprocedural_view() && - "use construct_ip_backedges"); - max_loop_depth = 0; - - current_ir_graph = irg; - outermost_ir_graph = irg; - - init_scc(current_ir_graph); - - current_loop = NULL; - new_loop(); /* sets current_loop */ - head_rem = current_loop; /* Just for assertion */ - - inc_irg_visited(current_ir_graph); - - cfscc(get_irg_end_block(current_ir_graph)); - for (i = 0; i < get_End_n_keepalives(end); i++) { - ir_node *el = get_End_keepalive(end, i); - if (is_Block(el)) cfscc(el); - } - - assert(head_rem == current_loop); - set_irg_loop(current_ir_graph, current_loop); - set_irg_loopinfo_state(current_ir_graph, loopinfo_cf_consistent); - assert(get_irg_loop(current_ir_graph)->kind == k_ir_loop); - - current_ir_graph = rem; - return max_loop_depth; + if (get_irn_dfn(n) == get_irn_uplink(n)) { + /* This condition holds for + 1) the node with the incoming backedge. + That is: We found a cfloop! + 2) Straight line code, because no uplink has been propagated, so the + uplink still is the same as the dfn. + + But n might not be a proper cfloop head for the analysis. Proper cfloop + heads are Block and Phi nodes. find_tail searches the stack for + Block's and Phi's and takes those nodes as cfloop heads for the current + cfloop instead and marks the incoming edge as backedge. */ + + ir_node *tail = find_tail(n); + if (tail) { + /* We have a cfloop, that is no straight line code, + because we found a cfloop head! + Next actions: Open a new cfloop on the cfloop tree and + try to find inner cfloops */ + + /* This is an adaption of the algorithm from fiasco / optscc to + * avoid cfloops without Block or Phi as first node. This should + * severely reduce the number of evaluations of nodes to detect + * a fixpoint in the heap analysis. + * Further it avoids cfloops without firm nodes that cause errors + * in the heap analyses. */ + + ir_loop *l; + int close; + if ((get_loop_n_elements(current_loop) > 0) || (is_outermost_loop(current_loop))) { + l = new_loop(); + close = 1; + } else { + l = current_loop; + close = 0; + } + + /* Remove the cfloop from the stack ... */ + pop_scc_unmark_visit(n); + + /* The current backedge has been marked, that is temporarily eliminated, + by find tail. Start the scc algorithm + anew on the subgraph thats left (the current cfloop without the backedge) + in order to find more inner cfloops. */ + + cfscc(tail); + + assert(irn_visited(n)); + if (close) + close_loop(l); + } else { + /* AS: No cfloop head was found, that is we have straight line code. + Pop all nodes from the stack to the current cfloop. */ + pop_scc_to_loop(n); + } + } } +void construct_cf_backedges(ir_graph *irg) +{ + ir_loop *head_rem; + ir_node *end = get_irg_end(irg); + struct obstack temp; + int i; -int construct_ip_cf_backedges (void) { - ir_graph *rem = current_ir_graph; - int rem_ipv = get_interprocedural_view(); - int i; - - assert(get_irp_ip_view_state() == ip_view_valid); - max_loop_depth = 0; - outermost_ir_graph = get_irp_main_irg(); - - init_ip_scc(); - - current_loop = NULL; - new_loop(); /* sets current_loop */ - set_interprocedural_view(true); - - inc_max_irg_visited(); - for (i = 0; i < get_irp_n_irgs(); i++) - set_irg_visited(get_irp_irg(i), get_max_irg_visited()); - - /** We have to start the walk at the same nodes as cg_walk. **/ - /* Walk starting at unreachable procedures. Only these - * have End blocks visible in interprocedural view. */ - for (i = 0; i < get_irp_n_irgs(); i++) { - ir_node *sb; - current_ir_graph = get_irp_irg(i); - - sb = get_irg_start_block(current_ir_graph); - - if ((get_Block_n_cfgpreds(sb) > 1) || - (get_nodes_block(get_Block_cfgpred(sb, 0)) != sb)) continue; - - cfscc(get_irg_end_block(current_ir_graph)); - } - - /* Check whether we walked all procedures: there could be procedures - with cyclic calls but no call from the outside. */ - for (i = 0; i < get_irp_n_irgs(); i++) { - ir_node *sb; - current_ir_graph = get_irp_irg(i); - - /* Test start block: if inner procedure end and end block are not - * visible and therefore not marked. */ - sb = get_irg_start_block(current_ir_graph); - if (get_irn_visited(sb) < get_irg_visited(current_ir_graph)) cfscc(sb); - } - - /* Walk all endless cfloops in inner procedures. - * We recognize an inner procedure if the End node is not visited. */ - for (i = 0; i < get_irp_n_irgs(); i++) { - ir_node *e; - current_ir_graph = get_irp_irg(i); - - e = get_irg_end(current_ir_graph); - if (get_irn_visited(e) < get_irg_visited(current_ir_graph)) { - int j; - /* Don't visit the End node. */ - for (j = 0; j < get_End_n_keepalives(e); j++) { - ir_node *el = get_End_keepalive(e, j); - if (is_Block(el)) cfscc(el); - } - } - } - - set_irg_loop(outermost_ir_graph, current_loop); - set_irg_loopinfo_state(current_ir_graph, loopinfo_cf_ip_consistent); - assert(get_irg_loop(outermost_ir_graph)->kind == k_ir_loop); - - current_ir_graph = rem; - set_interprocedural_view(rem_ipv); - return max_loop_depth; -} + outermost_ir_graph = irg; + obstack_init(&temp); + init_scc(irg, &temp); -static void reset_backedges(ir_node *n) { - int rem = get_interprocedural_view(); + current_loop = NULL; + new_loop(); /* sets current_loop */ + head_rem = current_loop; /* Just for assertion */ - assert(is_Block(n)); - set_interprocedural_view(true); - clear_backedges(n); - set_interprocedural_view(false); - clear_backedges(n); - set_interprocedural_view(rem); -} + inc_irg_visited(irg); -static void loop_reset_backedges(ir_loop *l) { - int i; - reset_backedges(get_loop_node(l, 0)); - for (i = 0; i < get_loop_n_nodes(l); ++i) - set_irn_loop(get_loop_node(l, i), NULL); - for (i = 0; i < get_loop_n_sons(l); ++i) { - loop_reset_backedges(get_loop_son(l, i)); - } -} + /* walk over all blocks of the graph, including keep alives */ + cfscc(get_irg_end_block(irg)); + for (i = get_End_n_keepalives(end) - 1; i >= 0; --i) { + ir_node *el = get_End_keepalive(end, i); + if (is_Block(el)) + cfscc(el); + } + finish_scc(); + obstack_free(&temp, NULL); -/* Removes all cfloop information. - Resets all backedges */ -void free_cfloop_information(ir_graph *irg) { - if (get_irg_loop(irg)) - loop_reset_backedges(get_irg_loop(irg)); - set_irg_loop(irg, NULL); - set_irg_loopinfo_state(current_ir_graph, loopinfo_none); - /* We cannot free the cfloop nodes, they are on the obstack. */ + assert(head_rem == current_loop); + mature_loops(current_loop, get_irg_obstack(irg)); + set_irg_loop(irg, current_loop); + add_irg_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_LOOPINFO); } - -void free_all_cfloop_information (void) { - int i; - int rem = get_interprocedural_view(); - set_interprocedural_view(true); /* To visit all filter nodes */ - for (i = 0; i < get_irp_n_irgs(); i++) { - free_cfloop_information(get_irp_irg(i)); - } - set_interprocedural_view(rem); +void assure_loopinfo(ir_graph *irg) +{ + if (irg_has_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_LOOPINFO)) + return; + construct_cf_backedges(irg); }