X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fana%2Firscc.c;h=9ae89f97a6aed3845533c77fece7aa62bb98f74a;hb=8aca33381b3dea1ef0bb6c120f59989075c438d1;hp=75c74cbd66a5ff6f674276b9ea61c53a972b3f09;hpb=0ae2b59b6f9571c7163b9b5bc4e4563b1362edb5;p=libfirm diff --git a/ir/ana/irscc.c b/ir/ana/irscc.c index 75c74cbd6..9ae89f97a 100644 --- a/ir/ana/irscc.c +++ b/ir/ana/irscc.c @@ -1,28 +1,21 @@ /* - * Project: libFIRM - * File name: ir/ana/irscc.c - * Purpose: Compute the strongly connected regions and build + * This file is part of libFirm. + * Copyright (C) 2012 University of Karlsruhe. + */ + +/** + * @file + * @brief Compute the strongly connected regions and build * backedge/loop 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. + * @author Goetz Lindenmaier + * @date 7.2002 */ +#include "config.h" -#ifdef HAVE_CONFIG_H -# include "config.h" -#endif - -#ifdef HAVE_STRING_H -# include -#endif -#ifdef HAVE_STDLIB_H -# include -#endif +#include +#include #include "irloop_t.h" @@ -30,189 +23,153 @@ #include "irgraph_t.h" #include "irnode_t.h" #include "irgwalk.h" +#include "irdump.h" #include "array.h" #include "pmap.h" - -#include "irdump.h" - -/* A variant of the loop tree that avoids loops without head. - This reduces the depth of the loop tree. */ -#define NO_LOOPS_WITHOUT_HEAD 1 - -static ir_graph *outermost_ir_graph; /* The outermost graph the scc is computed - for */ -static ir_loop *current_loop; /* Current loop construction is working - on. */ -static int loop_node_cnt = 0; /* Counts the number of allocated loop nodes. - Each loop 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); -void set_projx_link(ir_node *cb_projx, ir_node *end_projx); -ir_node *get_projx_link(ir_node *cb_projx); - -/**********************************************************************/ -/* Node attributes **/ -/**********************************************************************/ +#include "ircons.h" + +/** The outermost graph the scc is computed for. */ +static ir_graph *outermost_ir_graph; +/** Current loop construction is working on. */ +static ir_loop *current_loop; +/** Counts the number of allocated loop nodes. + * Each loop 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. **/ /**********************************************************************/ typedef struct scc_info { - int in_stack; /**< Marks whether node is on the stack. */ - int dfn; /**< Depth first search number. */ - int uplink; /**< dfn number of ancestor. */ - /* ir_loop *loop; *//* Refers to the containing loop. */ - /* - struct section *section; - xset def; - xset use; - */ + 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; -} - -static INLINE void -mark_irn_in_stack (ir_node *n) { - scc_info *scc = get_irn_link(n); - assert(scc); - scc->in_stack = 1; -} - -static INLINE void -mark_irn_not_in_stack (ir_node *n) { - scc_info *scc = get_irn_link(n); - assert(scc); - scc->in_stack = 0; -} - -static INLINE int -irn_is_in_stack (ir_node *n) { - scc_info *scc = get_irn_link(n); - assert(scc); - return scc->in_stack; -} - -static INLINE void -set_irn_uplink (ir_node *n, int uplink) { - scc_info *scc = get_irn_link(n); - assert(scc); - scc->uplink = uplink; +/** + * Allocates a new SCC info on the given obstack. + */ +static inline scc_info *new_scc_info(struct obstack *obst) +{ + return OALLOCZ(obst, scc_info); } -int -get_irn_uplink (ir_node *n) { - scc_info *scc = get_irn_link(n); - assert(scc); - return scc->uplink; +/** + * Mark node n being on the SCC stack. + */ +static inline void mark_irn_in_stack(ir_node *n) +{ + scc_info *scc = (scc_info*) get_irn_link(n); + assert(scc); + scc->in_stack = 1; } -static INLINE void -set_irn_dfn (ir_node *n, int dfn) { - scc_info *scc = get_irn_link(n); - assert(scc); - scc->dfn = dfn; +/** +* Mark node n NOT being on the SCC stack. +*/ +static inline void mark_irn_not_in_stack(ir_node *n) +{ + scc_info *scc = (scc_info*) get_irn_link(n); + assert(scc); + scc->in_stack = 0; } -int -get_irn_dfn (ir_node *n) { - scc_info *scc = get_irn_link(n); - assert(scc); - return scc->dfn; +/** + * Checks if a node is on the SCC stack. + */ +static inline int irn_is_in_stack(ir_node *n) +{ + scc_info *scc = (scc_info*) get_irn_link(n); + assert(scc); + return scc->in_stack; } - -void -set_irn_loop (ir_node *n, ir_loop *loop) { - n->loop = loop; +/** + * Sets the uplink number for a node. + */ +static inline void set_irn_uplink(ir_node *n, int uplink) +{ + scc_info *scc = (scc_info*) get_irn_link(n); + assert(scc); + scc->uplink = uplink; } -/* Uses temporary information to get the loop */ -ir_loop *(get_irn_loop)(const ir_node *n) { - return _get_irn_loop(n); +/** + * Returns the uplink number for a node. + */ +static int get_irn_uplink(ir_node *n) +{ + scc_info *scc = (scc_info*) get_irn_link(n); + assert(scc); + return scc->uplink; } - -#if 0 -static ir_loop *find_nodes_loop (ir_node *n, ir_loop *l) { - int i; - ir_loop *res = NULL; - - /* Test whether n is contained in this loop. */ - for (i = 0; i < get_loop_n_nodes(l); i++) - if (n == get_loop_node(l, i)) return l; - - /* Is this a leave in the loop tree? If so loop not found. */ - if (get_loop_n_sons(l) == 0) return NULL; - - /* Else descend in the loop tree. */ - for (i = 0; i < get_loop_n_sons(l); i++) { - res = find_nodes_loop(n, get_loop_son(l, i)); - if (res) break; - } - return res; +/** + * Sets the depth-first-search number for a node. + */ +static inline void set_irn_dfn(ir_node *n, int dfn) +{ + scc_info *scc = (scc_info*) get_irn_link(n); + assert(scc); + scc->dfn = dfn; } -/* @@@ temporary implementation, costly!!! */ -ir_loop * get_irn_loop(ir_node *n) { - ir_loop *l = get_irg_loop(current_ir_graph); - l = find_nodes_loop(n, l); - return l; +/** + * Returns the depth-first-search number of a node. + */ +static int get_irn_dfn(ir_node *n) +{ + scc_info *scc = (scc_info*) get_irn_link(n); + assert(scc); + return scc->dfn; } -#endif /**********************************************************************/ /* A stack. **/ /**********************************************************************/ static ir_node **stack = NULL; -static int tos = 0; /* top of stack */ +static size_t tos = 0; /* top of stack */ /** * initializes the 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 inline void init_stack(void) +{ + if (stack) { + ARR_RESIZE(ir_node *, stack, 1000); + } else { + stack = NEW_ARR_F(ir_node *, 1000); + } + tos = 0; } -#if 0 -static INLINE void free_stack(void) { - DEL_ARR_F(stack); - stack = NULL; - tos = 0; +/** + * Frees the stack. + */ +static void finish_stack(void) +{ + DEL_ARR_F(stack); + stack = NULL; } -#endif /** * push a node onto the stack * * @param n The node to push */ -static INLINE void -push (ir_node *n) +static inline void push(ir_node *n) { - /*DDMN(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); } /** @@ -220,83 +177,72 @@ push (ir_node *n) * * @return The topmost node */ -static INLINE ir_node * -pop (void) +static inline ir_node *pop(void) { - ir_node *n = stack[--tos]; - mark_irn_not_in_stack(n); - return n; + ir_node *n; + + assert(tos > 0); + 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) +static inline void pop_scc_to_loop(ir_node *n) { - ir_node *m; - int i = 0; + ir_node *m; - do { - m = pop(); + do { + m = pop(); - //printf(" dfn: %d, upl %d upl-new %d ", get_irn_dfn(m), get_irn_uplink(m), loop_node_cnt+1); DDMN(m); - - loop_node_cnt++; - set_irn_dfn(m, loop_node_cnt); - add_loop_node(current_loop, m); - set_irn_loop(m, current_loop); - i++; - - /* if (m==n) break;*/ - } while(m != n); - - /* i might be bigger than 1 for dead (and that's why bad) loops */ - /* if(i > 1) - printf("Mehr als eine Iteration!!!!!!!!!!!!!!!!!!!!!!!!!!!!11111\n"); - */ + 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 loops 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; + 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; + 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; + lelement = get_loop_element(last_son, 0); + gson = lelement.son; - if (get_kind(gson) == k_ir_loop) { - loop_element new_last_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; - } - } + gson->outer_loop = l; + new_last_son.son = gson; + l->children[last] = new_last_son; + } + } - current_loop = l; + 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) +static inline void pop_scc_unmark_visit(ir_node *n) { - ir_node *m = NULL; + ir_node *m = NULL; - while (m != n) { - m = pop(); - set_irn_visited(m, 0); - } + while (m != n) { + m = pop(); + set_irn_visited(m, 0); + } } /**********************************************************************/ @@ -305,1156 +251,491 @@ pop_scc_unmark_visit (ir_node *n) /* Allocates a new loop as son of current_loop. Sets current_loop to the new loop and returns the father. */ -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; -} - -#if 0 -/* Finishes the datastructures, copies the arrays to the obstack - of current_ir_graph. - A. Schoesser: Caution: loop -> sons is gone. */ -static void mature_loop (ir_loop *loop) { - ir_loop **new_sons; - - new_sons = NEW_ARR_D (ir_loop *, current_ir_graph->obst, ARR_LEN(loop->sons)); - memcpy (new_sons, loop->sons, sizeof (ir_loop *) * ARR_LEN(loop->sons)); - DEL_ARR_F(loop->sons); - loop->sons = new_sons; -} -#endif - -/* Returns outer loop, itself if outermost. */ -ir_loop *(get_loop_outer_loop)(const ir_loop *loop) { - return _get_loop_outer_loop(loop); -} - -/* Returns nesting depth of this loop */ -int (get_loop_depth)(const ir_loop *loop) { - return _get_loop_depth(loop); -} - -/* Returns the number of inner loops */ -int (get_loop_n_sons)(const ir_loop *loop) { - return _get_loop_n_sons(loop); -} - -/* Returns the pos`th loop_node-child * - * TODO: This method isn`t very efficient ! * - * Returns NULL if there isn`t a pos`th loop_node */ -ir_loop *get_loop_son (ir_loop *loop, int pos) { - int child_nr = 0, loop_nr = -1; - - assert(loop && loop->kind == k_ir_loop); - while(child_nr < ARR_LEN(loop->children)) - { - if(*(loop -> children[child_nr].kind) == k_ir_loop) - loop_nr++; - if(loop_nr == pos) - return(loop -> children[child_nr].son); - child_nr++; - } - return NULL; -} - -/* Use EXCLUSIVELY this function to add sons, otherwise the loop->n_sons - is invalid! */ - -void -add_loop_son(ir_loop *loop, ir_loop *son) { - loop_element lson; - lson.son = son; - assert(loop && loop->kind == k_ir_loop); - assert(get_kind(son) == k_ir_loop); - ARR_APP1 (loop_element, loop->children, lson); - loop -> n_sons++; -} - -/* Returns the number of nodes in the loop */ -int get_loop_n_nodes (ir_loop *loop) { - assert(loop); assert(loop->kind == k_ir_loop); - return loop -> n_nodes; -/* return ARR_LEN(loop->nodes); */ -} - -/* Returns the pos`th ir_node-child * - * TODO: This method isn`t very efficient ! * - * Returns NULL if there isn`t a pos`th ir_node */ -ir_node *get_loop_node (ir_loop *loop, int pos) { - int child_nr, node_nr = -1; - - assert(loop && loop->kind == k_ir_loop); - assert(pos < get_loop_n_nodes(loop)); - - for (child_nr = 0; child_nr < ARR_LEN(loop->children); child_nr++) { - if(*(loop -> children[child_nr].kind) == k_ir_node) - node_nr++; - if(node_nr == pos) - return(loop -> children[child_nr].node); - } - DDML(loop); - printf("pos: %d\n", pos); - assert(0 && "no child at pos found"); - return NULL; -} - -/* Use EXCLUSIVELY this function to add nodes, otherwise the loop->n_nodes - is invalid! */ - -void -add_loop_node(ir_loop *loop, ir_node *n) { - loop_element ln; - ln.node = n; - assert(loop && loop->kind == k_ir_loop); - assert(get_kind(n) == k_ir_node || get_kind(n) == k_ir_graph); /* used in callgraph.c */ - ARR_APP1 (loop_element, loop->children, ln); - loop->n_nodes++; -} - -/** Returns the number of elements contained in loop. */ -int get_loop_n_elements (ir_loop *loop) { - assert(loop && loop->kind == k_ir_loop); - return(ARR_LEN(loop->children)); -} - -/* - Returns the pos`th loop element. - This may be a loop_node or a ir_node. The caller of this function has - to check the *(loop_element.kind) field for "k_ir_node" or "k_ir_loop" - and then select the appropriate "loop_element.node" or "loop_element.son". -*/ - -loop_element get_loop_element (ir_loop *loop, int pos) { - assert(loop && loop->kind == k_ir_loop && pos < ARR_LEN(loop->children)); - - return(loop -> children[pos]); -} - -int get_loop_element_pos(ir_loop *loop, void *le) { - int i; - assert(loop && loop->kind == k_ir_loop); - - for (i = 0; i < get_loop_n_elements(loop); i++) - if (get_loop_element(loop, i).node == le) return i; - return -1; -} - -int get_loop_loop_nr(ir_loop *loop) { - assert(loop && loop->kind == k_ir_loop); -#ifdef DEBUG_libfirm - return loop->loop_nr; -#else - return (int)loop; -#endif -} - - -/** A field to connect additional information to a loop. Only valid - if libfirm_debug is set. */ -void set_loop_link (ir_loop *loop, void *link) { - assert(loop && loop->kind == k_ir_loop); -#ifdef DEBUG_libfirm - loop->link = link; -#endif -} -void *get_loop_link (const ir_loop *loop) { - assert(loop && loop->kind == k_ir_loop); -#ifdef DEBUG_libfirm - return loop->link; -#else - return NULL; -#endif -} - -int (is_ir_loop)(const void *thing) { - return _is_ir_loop(thing); -} - -/* The outermost loop is remarked in the surrounding graph. */ -void (set_irg_loop)(ir_graph *irg, ir_loop *loop) { - _set_irg_loop(irg, loop); -} +static ir_loop *new_loop(void) +{ + ir_loop *father = current_loop; + ir_loop *son = alloc_loop(father, get_irg_obstack(outermost_ir_graph)); -/* Returns the root loop info (if exists) for an irg. */ -ir_loop *(get_irg_loop)(ir_graph *irg) { - return _get_irg_loop(irg); + current_loop = son; + return father; } - /**********************************************************************/ /* Constructing and destructing the loop/backedge information. **/ /**********************************************************************/ /* Initialization steps. **********************************************/ -static INLINE void -init_node (ir_node *n, void *env) { - set_irn_link (n, new_scc_info()); - clear_backedges(n); +static inline void init_node(ir_node *n, void *env) +{ + struct obstack *obst = (struct obstack*) env; + set_irn_link(n, new_scc_info(obst)); + clear_backedges(n); } -static INLINE void -init_scc_common (void) { - current_dfn = 1; - loop_node_cnt = 0; - init_stack(); +static inline void init_scc_common(void) +{ + current_dfn = 1; + loop_node_cnt = 0; + init_stack(); } -static INLINE void -init_scc (ir_graph *irg) { - init_scc_common(); - irg_walk_graph (irg, init_node, NULL, NULL); - /* - irg_walk (irg, link_to_reg_end, NULL, NULL); - */ +static inline void init_scc(ir_graph *irg, struct obstack *obst) +{ + init_scc_common(); + irg_walk_graph(irg, init_node, NULL, obst); } -static INLINE void -init_ip_scc (void) { - init_scc_common(); - cg_walk (init_node, NULL, NULL); - -#if EXPERIMENTAL_LOOP_TREE - cg_walk (link_to_reg_end, NULL, NULL); -#endif +static inline void finish_scc(void) +{ + finish_stack(); } -/* Condition for breaking the recursion. */ -static int is_outermost_Start(ir_node *n) { - /* Test whether this is the outermost Start node. If so - recursion must end. */ - if ((get_irn_op(n) == op_Block) && - (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 1; - } -#if 0 - /* @@@ Bad condition: - not possible in interprocedural view as outermost_graph is - not necessarily the only with a dead-end start block. - Besides current_ir_graph is not set properly. */ - if ((get_irn_op(n) == op_Block) && - (n == get_irg_start_block(current_ir_graph))) { - if ((!get_interprocedural_view()) || - (current_ir_graph == outermost_ir_graph)) - return 1; - } -#endif - return 0; +/** + * Check whether a given node represents the outermost Start + * block. In intra-procedural view this is the start block of the + * current graph, in interprocedural view it is the start block + * of the outer most graph. + * + * @param n the node to check + * + * This is the condition for breaking the scc recursion. + */ +static int is_outermost_Start(ir_node *n) +{ + /* Test whether this is the outermost Start node. */ + if (is_Block(n) && get_Block_n_cfgpreds(n) == 1) { + ir_node *pred = skip_Proj(get_Block_cfgpred(n, 0)); + if (is_Start(pred) && get_nodes_block(pred) == n) + return 1; + } + return 0; } /* When to walk from nodes to blocks. Only for Control flow operations? */ -static INLINE int -get_start_index(ir_node *n) { -#undef BLOCK_BEFORE_NODE -#define BLOCK_BEFORE_NODE 1 - -#if BLOCK_BEFORE_NODE - - /* This version assures, that all nodes are ordered absolutely. This allows - to undef all nodes in the heap analysis if the block is false, which means - not reachable. - I.e., with this code, the order on the loop tree is correct. But a (single) - test showed the loop tree is deeper. */ - if (get_irn_op(n) == op_Phi || - get_irn_op(n) == op_Block || - (get_irn_op(n) == op_Filter && get_interprocedural_view()) || - (get_irg_pinned(get_irn_irg(n)) == op_pin_state_floats && - get_irn_pinned(n) == op_pin_state_floats)) - // Here we could test for backedge at -1 which is illegal - return 0; - else - return -1; - -#else - - /* This version causes deeper loop trees (at least we verified this - for Polymor). - But it guarantees that Blocks are analysed before nodes contained in the - block. If so, we can set the value to undef if the block is not \ - executed. */ - if (is_cfop(n) || is_fragile_op(n) || get_irn_op(n) == op_Start) - return -1; - else - return 0; - -#endif +static inline int get_start_index(ir_node *n) +{ + /* This version assures, that all nodes are ordered absolutely. This allows + to undef all nodes in the heap analysis if the block is false, which + means not reachable. + I.e., with this code, the order on the loop tree is correct. But a + (single) test showed the loop tree is deeper. */ + if (is_Phi(n) || + is_Block(n) || + (get_irg_pinned(get_irn_irg(n)) == op_pin_state_floats && + get_irn_pinned(n) == op_pin_state_floats)) + // Here we could test for backedge at -1 which is illegal + return 0; + else + return -1; } +/** + * Return non-zero if the given node is a legal loop header: + * Block, Phi + * + * @param n the node to check + */ +static inline int is_possible_loop_head(ir_node *n) +{ + return is_Block(n) || is_Phi(n); +} -#if 0 -static void test(ir_node *pred, ir_node *root, ir_node *this) { - int i; - if (get_irn_uplink(pred) >= get_irn_uplink(root)) return; - - printf("this: %d ", get_irn_uplink(this)); DDMN(this); - printf("pred: %d ", get_irn_uplink(pred)); DDMN(pred); - printf("root: %d ", get_irn_uplink(root)); DDMN(root); +/** + * Returns non-zero if n is a loop header, i.e., it is a Block or Phi + * node and has predecessors within the loop and out of the loop. + * + * @param n the node to check + * @param root only needed for assertion. + */ +static int is_head(ir_node *n, ir_node *root) +{ + int i, arity; + int some_outof_loop = 0, some_in_loop = 0; - printf("tos: %d\n", tos); + /* Test for legal loop header: Block, Phi, ... */ + if (!is_possible_loop_head(n)) + return 0; - for (i = tos; i >= 0; i--) { - ir_node *n = stack[i]; - if (!n) continue; - printf(" uplink: %d, pos: %d ", get_irn_uplink(n), i); DDMN(n); - } -} + if (!is_outermost_Start(n)) { +#ifndef NDEBUG + int uplink = get_irn_uplink(root); +#else + (void) root; #endif - -/* Test for legal loop header: Block, Phi, ... */ -static INLINE int is_possible_loop_head(ir_node *n) { - ir_op *op = get_irn_op(n); - return ((op == op_Block) || - (op == op_Phi) || - ((op == op_Filter) && get_interprocedural_view())); -} - -/* Returns non-zero if n is a loop header, i.e., it is a Block, Phi - or Filter node and has predecessors within the loop and out - of the loop. - @arg root: only needed for assertion. */ -static int -is_head (ir_node *n, ir_node *root) -{ - int i, arity; - int some_outof_loop = 0, some_in_loop = 0; - - /* Test for legal loop header: Block, Phi, ... */ - if (!is_possible_loop_head(n)) - return 0; - - if (!is_outermost_Start(n)) { - arity = get_irn_arity(n); - for (i = get_start_index(n); i < arity; i++) { - ir_node *pred = get_irn_n(n, i); - assert(pred); - 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(n); DDMN(pred); DDMN(root); - assert(get_irn_uplink(pred) >= get_irn_uplink(root)); - } - some_in_loop = 1; - } - } - } - return some_outof_loop && some_in_loop; + arity = get_irn_arity(n); + for (i = get_start_index(n); i < arity; i++) { + ir_node *pred; + if (is_backedge(n, i)) + continue; + pred = get_irn_n(n, i); + if (! irn_is_in_stack(pred)) { + some_outof_loop = 1; + } else { + assert(get_irn_uplink(pred) >= uplink); + some_in_loop = 1; + } + } + } + return some_outof_loop & some_in_loop; } /** * Returns non-zero if n is possible loop head of an endless loop. - * I.e., it is a Block, Phi or Filter node and has only predecessors + * I.e., it is a Block or Phi node and has only predecessors * within the loop. - * @param root: only needed for assertion. + * + * @param n the node to check + * @param root only needed for assertion. */ -static int -is_endless_head (ir_node *n, ir_node *root) +static int is_endless_head(ir_node *n, ir_node *root) { - int i, arity; - int some_outof_loop = 0, some_in_loop = 0; - - /* Test for legal loop header: Block, Phi, ... */ - if (!is_possible_loop_head(n)) - return 0; - - if (!is_outermost_Start(n)) { - arity = get_irn_arity(n); - for (i = get_start_index(n); i < arity; i++) { - ir_node *pred = 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)); - } - some_in_loop = 1; - } - } - } - return !some_outof_loop && some_in_loop; -} + int i, arity; + int none_outof_loop = 1, some_in_loop = 0; -/* 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_Start(n)) { - int arity = get_irn_arity(n); - for (i = get_start_index(n); i < arity; i++) { - ir_node *pred = get_irn_n(n, i); - assert(pred); - 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; -} + /* Test for legal loop header: Block, Phi, ... */ + if (!is_possible_loop_head(n)) + return 0; -/* Returns index of the predecessor with the largest dfn number. */ -static int -largest_dfn_pred (ir_node *n) + if (!is_outermost_Start(n)) { +#ifndef NDEBUG + int uplink = get_irn_uplink(root); +#else + (void) root; +#endif + arity = get_irn_arity(n); + for (i = get_start_index(n); i < arity; i++) { + ir_node *pred; + if (is_backedge(n, i)) + continue; + pred = get_irn_n(n, i); + if (!irn_is_in_stack(pred)) { + none_outof_loop = 0; + } else { + assert(get_irn_uplink(pred) >= uplink); + some_in_loop = 1; + } + } + } + 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) { - int i, index = -2, max = -1; - - if (!is_outermost_Start(n)) { - int arity = get_irn_arity(n); - for (i = get_start_index(n); i < arity; i++) { - ir_node *pred = 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. - ("disable_backedge" in fiasco) -* -* @param n A node where uplink == dfn. -**/ - -static ir_node * -find_tail (ir_node *n) { - ir_node *m; - int i, res_index = -2; - - /* - if (!icfg && rm_cyclic_phis && remove_cyclic_phis (n)) return NULL; - */ - 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; // Is this to catch Phi - self loops? - 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)) { /* dont walk past loop head. */ - i = -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 = -1; - break; - } - - } - - 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; - } - if (m == n) { break; } /* It's not an unreachable loop, either. */ - } - //assert(0 && "no head found on stack"); - } - - } - if (res_index <= -2) { - /* It's a completely bad loop: without Phi/Block nodes that can - be a head. I.e., the code is "dying". We break the loop by - setting Bad nodes. */ - int arity = get_irn_arity(n); - for (i = -1; i < arity; ++i) { - set_irn_n(n, i, get_irg_bad(get_irn_irg(n))); - } - return NULL; - } - assert (res_index > -2); - - set_backedge (m, res_index); - return is_outermost_Start(n) ? NULL : get_irn_n(m, res_index); + int i, index = -2, min = -1; + + if (!is_outermost_Start(n)) { + int arity = get_irn_arity(n); + for (i = get_start_index(n); i < arity; i++) { + ir_node *pred = 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; } - -#if EXPERIMENTAL_LOOP_TREE - -/* ---------------------------------------------------------------- - AS: This is experimental code to build loop trees suitable for - the heap analysis. Does not work correctly right now... :-( - - - Search in stack for the corresponding first Call-End-ProjX that - corresponds to one of the control flow predecessors of the given - block, that is the possible callers. - returns: the control predecessor to chose\ - or -1 if no corresponding Call-End-Node could be found - on the stack. - - -------------------------------------------------------------- */ - -int search_endproj_in_stack(ir_node *start_block) +/** + * Returns index of the predecessor with the largest dfn number. + */ +static int largest_dfn_pred(ir_node *n) { - int i, j; - assert(is_Block(start_block)); - for(i = tos - 1; i >= 0; --i) - { - DDMN(stack[i]); - if(get_irn_op(stack[i]) == op_Proj && get_irn_mode(stack[i]) == mode_X && - get_irn_op(get_irn_n(stack[i], 0)) == op_EndReg) - { - printf("FOUND PROJ!!!!!!!!!!!!!!!!!!!!!!!!!!\n"); - ir_node *end_projx = stack[i]; - - int arity = get_irn_arity(start_block); - for(j = 0; j < arity; j++) - { - ir_node *begin_projx = get_Block_cfgpred(get_irg_start_block(get_irn_irg(end_projx)), - get_Proj_proj(end_projx)); - DDMN(begin_projx); - if(get_irn_n(start_block, j) == begin_projx) - { - printf("FOUND IT!!!!!!!!!!!!!!!!!!\n"); - return(j); - } - } - } - } - return(-1); + int i, index = -2, max = -1; + + if (!is_outermost_Start(n)) { + int arity = get_irn_arity(n); + for (i = get_start_index(n); i < arity; i++) { + ir_node *pred = 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; } - -static pmap *projx_link = NULL; - -void link_to_reg_end (ir_node *n, void *env) { - if(get_irn_op(n) == op_Proj && - get_irn_mode(n) == mode_X && - get_irn_op(get_irn_n(n, 0)) == op_EndReg) { - /* Reg End Projx -> Find the CallBegin Projx and hash it */ - ir_node *end_projx = n; - ir_node *begin_projx = get_Block_cfgpred(get_irg_start_block(get_irn_irg(end_projx)), - get_Proj_proj(end_projx)); - printf("Linked the following ProjxNodes:\n"); - DDMN(begin_projx); - DDMN(end_projx); - set_projx_link(begin_projx, end_projx); - } -} - -void set_projx_link(ir_node *cb_projx, ir_node *end_projx) +/** + * 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. + * ("disable_backedge" in fiasco) + * + * @param n A node where uplink == dfn. + */ +static ir_node *find_tail(ir_node *n) { - if(projx_link == NULL) - projx_link = pmap_create(); - pmap_insert(projx_link, (void *)cb_projx, (void *)end_projx); -} - -ir_node *get_projx_link(ir_node *cb_projx) + 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; // Is this to catch Phi - self loops? + 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)) { /* don't walk past loop head. */ + i = -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 = -1; + break; + } + } + + 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; + } + /* It's not an unreachable loop, either. */ + if (m == n) + break; + } + //assert(0 && "no head found on stack"); + } + + } + if (res_index <= -2) { + /* It's a completely bad loop: without Phi/Block nodes that can + be a head. I.e., the code is "dying". We break the loop by + setting Bad nodes. */ + ir_graph *irg = get_irn_irg(n); + ir_mode *mode = get_irn_mode(n); + ir_node *bad = new_r_Bad(irg, mode); + int arity = get_irn_arity(n); + for (i = -1; i < arity; ++i) { + set_irn_n(n, i, bad); + } + return NULL; + } + assert(res_index > -2); + + set_backedge(m, res_index); + return is_outermost_Start(n) ? NULL : get_irn_n(m, res_index); +} + +static inline int is_outermost_loop(ir_loop *l) { - return((ir_node *) pmap_get(projx_link, (void *)cb_projx)); + return l == get_loop_outer_loop(l); } -#endif - -static INLINE int -is_outermost_loop(ir_loop *l) { - return l == get_loop_outer_loop(l); -} - - /*-----------------------------------------------------------* * The core algorithm. * *-----------------------------------------------------------*/ -static void scc (ir_node *n) { - int i; - 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_Start(n)) { - int arity = get_irn_arity(n); - - for (i = get_start_index(n); i < arity; i++) { - ir_node *m; - if (is_backedge(n, i)) continue; - m = get_irn_n(n, i); /* get_irn_ip_pred(n, i); */ - /* if ((!m) || (get_irn_op(m) == op_Unknown)) continue; */ - scc (m); - if (irn_is_in_stack(m)) { - /* Uplink of m is smaller if n->m is a backedge. - Propagate the uplink to mark the loop. */ - 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 loop! - 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 loop head for the analysis. Proper loop - heads are Block and Phi nodes. find_tail searches the stack for - Block's and Phi's and takes those nodes as loop heads for the current - loop instead and marks the incoming edge as backedge. */ - - ir_node *tail = find_tail(n); - if (tail) { - /* We have a loop, that is no straight line code, - because we found a loop head! - Next actions: Open a new loop on the loop tree and - try to find inner loops */ - -#if NO_LOOPS_WITHOUT_HEAD - /* This is an adaption of the algorithm from fiasco / optscc to - * avoid loops 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 loops without firm nodes that cause errors - * in the heap analyses. - * But attention: don't do it for the outermost loop: This loop - * is not iterated. A first block can be a loop head in case of - * an endless recursion. */ - - 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 loop 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 that is left (the current loop without the backedge) - in order to find more inner loops. */ - scc (tail); - - assert (irn_visited(n)); -#if NO_LOOPS_WITHOUT_HEAD - if (close) -#endif - close_loop(l); - } - else - { - /* No loop head was found, that is we have straightline code. - Pop all nodes from the stack to the current loop. */ - pop_scc_to_loop(n); - } - } -} - -static void my_scc (ir_node *n) { - int i; - 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_Start(n)) { - int arity = get_irn_arity(n); - - for (i = get_start_index(n); i < arity; i++) { - ir_node *m; - if (is_backedge(n, i)) continue; - m = get_irn_n(n, i); /* get_irn_ip_pred(n, i); */ - /* if ((!m) || (get_irn_op(m) == op_Unknown)) continue; */ - my_scc (m); - if (irn_is_in_stack(m)) { - /* Uplink of m is smaller if n->m is a backedge. - Propagate the uplink to mark the loop. */ - 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 loop! - 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 loop head for the analysis. Proper loop - heads are Block and Phi nodes. find_tail searches the stack for - Block's and Phi's and takes those nodes as loop heads for the current - loop instead and marks the incoming edge as backedge. */ - - ir_node *tail = find_tail(n); - if (tail) { - /* We have a loop, that is no straight line code, - because we found a loop head! - Next actions: Open a new loop on the loop tree and - try to find inner loops */ - -#if NO_LOOPS_WITHOUT_HEAD - /* This is an adaption of the algorithm from fiasco / optscc to - * avoid loops 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 loops 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 loop 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 that is left (the current loop without the backedge) - in order to find more inner loops. */ - my_scc (tail); - - assert (irn_visited(n)); -#if NO_LOOPS_WITHOUT_HEAD - if (close) -#endif - close_loop(l); - } - else - { - /* No loop head was found, that is we have straightline code. - Pop all nodes from the stack to the current loop. */ - pop_scc_to_loop(n); - } - } -} - -/* Constructs backedge information for irg. In interprocedural view constructs - backedges for all methods called by irg, too. */ -int construct_backedges(ir_graph *irg) { - ir_graph *rem = current_ir_graph; - ir_loop *head_rem; - - assert(!get_interprocedural_view() && - "not implemented, 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); - - scc(get_irg_end(current_ir_graph)); - - assert(head_rem == current_loop); - set_irg_loop(current_ir_graph, current_loop); - set_irg_loopinfo_state(current_ir_graph, loopinfo_consistent); - assert(get_irg_loop(current_ir_graph)->kind == k_ir_loop); - /* - irg->loops = current_loop; - if (icfg == 1) { - int count = 0; - int depth = 0; - count_loop (the_loop, &count, &depth); - } - } - */ - current_ir_graph = rem; - - return max_loop_depth; -} - - -int construct_ip_backedges (void) { - ir_graph *rem = current_ir_graph; - int rem_ipv = get_interprocedural_view(); - int i; - - max_loop_depth = 0; - assert(get_irp_ip_view_state() == ip_view_valid); - - outermost_ir_graph = get_irp_main_irg(); - - init_ip_scc(); - - current_loop = NULL; - new_loop(); /* sets current_loop */ - set_interprocedural_view(1); - - 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; - - scc(get_irg_end(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)) scc(sb); - } - - /* Walk all endless loops 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++) scc(get_End_keepalive(e, j)); - } - } - - set_irg_loop(outermost_ir_graph, current_loop); - set_irg_loopinfo_state(current_ir_graph, loopinfo_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; -} - -void my_construct_ip_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); - - outermost_ir_graph = get_irp_main_irg(); - - init_ip_scc(); - - current_loop = NULL; - new_loop(); /* sets current_loop */ - set_interprocedural_view(1); - - 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; - - my_scc(get_irg_end(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)) scc(sb); - } - - /* Walk all endless loops 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++) scc(get_End_keepalive(e, j)); - } - } +/** + * The core algorithm: Find strongly coupled components. + * + * @param n node to start + */ +static void scc(ir_node *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); + + /* 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_Start(n)) { + int i, arity = get_irn_arity(n); + + for (i = get_start_index(n); i < arity; ++i) { + ir_node *m; + if (is_backedge(n, i)) + continue; + m = get_irn_n(n, i); + scc(m); + if (irn_is_in_stack(m)) { + /* Uplink of m is smaller if n->m is a backedge. + Propagate the uplink to mark the loop. */ + 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 loop! + 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 loop head for the analysis. Proper loop + heads are Block and Phi nodes. find_tail() searches the stack for + Block's and Phi's and takes those nodes as loop heads for the current + loop instead and marks the incoming edge as backedge. */ + + ir_node *tail = find_tail(n); + if (tail != NULL) { + /* We have a loop, that is no straight line code, + because we found a loop head! + Next actions: Open a new loop on the loop tree and + try to find inner loops */ + + /* This is an adaption of the algorithm from fiasco / optscc to + * avoid loops 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 loops without firm nodes that cause errors + * in the heap analyses. + * But attention: don't do it for the outermost loop: This loop + * is not iterated. A first block can be a loop head in case of + * an endless recursion. */ + + 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 loop 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 + again on the subgraph that is left (the current loop without the backedge) + in order to find more inner loops. */ + scc(tail); + + assert(irn_visited(n)); + if (close) + close_loop(l); + } else { + /* No loop head was found, that is we have straight line code. + Pop all nodes from the stack to the current loop. */ + pop_scc_to_loop(n); + } + } +} + +void construct_backedges(ir_graph *irg) +{ + ir_graph *rem = current_ir_graph; + ir_loop *head_rem; + struct obstack temp; - set_irg_loop(outermost_ir_graph, current_loop); - set_irg_loopinfo_state(current_ir_graph, loopinfo_ip_consistent); - assert(get_irg_loop(outermost_ir_graph)->kind == k_ir_loop); + current_ir_graph = irg; + outermost_ir_graph = irg; - current_ir_graph = rem; - set_interprocedural_view(rem_ipv); -} + obstack_init(&temp); + init_scc(irg, &temp); -static void reset_backedges(ir_node *n) { - if (is_possible_loop_head(n)) { - int rem = get_interprocedural_view(); + current_loop = NULL; + new_loop(); /* sets current_loop */ + head_rem = current_loop; /* Just for assertion */ - set_interprocedural_view(1); - clear_backedges(n); - set_interprocedural_view(1); - clear_backedges(n); - set_interprocedural_view(rem); - } -} + inc_irg_visited(irg); + scc(get_irg_end(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)); - } -} -*/ + finish_scc(); + obstack_free(&temp, NULL); -static void loop_reset_node(ir_node *n, void *env) { - set_irn_loop(n, NULL); - reset_backedges(n); + 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); + assert(get_irg_loop(irg)->kind == k_ir_loop); + current_ir_graph = rem; } - -/** Removes all loop information. - Resets all backedges */ -void free_loop_information(ir_graph *irg) { - /* We can not use this recursion, as the loop might contain - illegal nodes by now. Why else would we throw away the - representation? - if (get_irg_loop(irg)) loop_reset_backedges(get_irg_loop(irg)); - */ - irg_walk_graph(irg, loop_reset_node, NULL, NULL); - set_irg_loop(irg, NULL); - set_irg_loopinfo_state(current_ir_graph, loopinfo_none); - /* We cannot free the loop nodes, they are on the obstack. */ +static void reset_backedges(ir_node *n) +{ + if (is_possible_loop_head(n)) { + clear_backedges(n); + } } - -void free_all_loop_information (void) { - int i; - int rem = get_interprocedural_view(); - set_interprocedural_view(1); /* To visit all filter nodes */ - for (i = 0; i < get_irp_n_irgs(); i++) { - free_loop_information(get_irp_irg(i)); - } - set_interprocedural_view(rem); +static void loop_reset_node(ir_node *n, void *env) +{ + (void) env; + set_irn_loop(n, NULL); + reset_backedges(n); } - - - - -/* Debug stuff *************************************************/ - -static int test_loop_node(ir_loop *l) { - int i, has_node = 0, found_problem = 0; - loop_element le; - - assert(l && l->kind == k_ir_loop); - - if (get_loop_n_elements(l) == 0) { - printf(" Loop completely empty! "); DDML(l); - found_problem = 1; - dump_loop(l, "-ha"); - } - - le = get_loop_element(l, 0); - if (*(le.kind) != k_ir_node) { - assert(le.kind && *(le.kind) == k_ir_loop); - printf(" First loop element is not a node! "); DDML(l); - printf(" "); DDML(le.son); - - found_problem = 1; - dump_loop(l, "-ha"); - } - - if ((*(le.kind) == k_ir_node) && !is_possible_loop_head(le.node)) { - printf(" Wrong node as head! "); DDML(l); - printf(" "); DDMN(le.node); - found_problem = 1; - dump_loop(l, "-ha"); - } - - if ((get_loop_depth(l) != 0) && - (*(le.kind) == k_ir_node) && !has_backedges(le.node)) { - printf(" Loop head has no backedges! "); DDML(l); - printf(" "); DDMN(le.node); - found_problem = 1; - dump_loop(l, "-ha"); - } - - /* Recur */ - has_node = 0; - for (i = 0; i < get_loop_n_elements(l); ++i) { - le = get_loop_element(l, i); - if (*(le.kind) == k_ir_node) - has_node++; - else - if (test_loop_node(le.son)) found_problem = 1; - } - - if (has_node == 0) { - printf(" Loop has no firm node! "); DDML(l); - found_problem = 1; - dump_loop(l, "-ha"); - } - - return found_problem; +void free_loop_information(ir_graph *irg) +{ + irg_walk_graph(irg, loop_reset_node, NULL, NULL); + set_irg_loop(irg, NULL); + clear_irg_properties(current_ir_graph, IR_GRAPH_PROPERTY_CONSISTENT_LOOPINFO); + /* We cannot free the loop nodes, they are on the obstack. */ } -/** Prints all loop nodes that - * - do not have any firm nodes, only loop sons - * - the header is not a Phi, Block or Filter. - */ -void find_strange_loop_nodes(ir_loop *l) { - int found_problem = 0; - printf("\nTesting loop "); DDML(l); - found_problem = test_loop_node(l); - printf("Finished Test\n\n"); - if (found_problem) exit(0); - +void free_all_loop_information(void) +{ + size_t i; + for (i = 0; i < get_irp_n_irgs(); i++) { + free_loop_information(get_irp_irg(i)); + } } /* ------------------------------------------------------------------- */ /* Simple analyses based on the loop information */ /* ------------------------------------------------------------------- */ -int is_loop_variant(ir_loop *l, ir_loop *b) { - int i, n_elems; +static int is_loop_variant(ir_loop *l, ir_loop *b) +{ + size_t i, n_elems; - if (l == b) return 1; + if (l == b) return 1; - n_elems = get_loop_n_elements(l); - for (i = 0; i < n_elems; ++i) { - loop_element e = get_loop_element(l, i); - if (is_ir_loop(e.kind)) - if (is_loop_variant(e.son, b)) - return 1; - } + n_elems = get_loop_n_elements(l); + for (i = 0; i < n_elems; ++i) { + loop_element e = get_loop_element(l, i); + if (is_ir_loop(e.kind)) + if (is_loop_variant(e.son, b)) + return 1; + } - return 0; + return 0; } -/* Test whether a value is loop invariant. - * - * @param n The node to be tested. - * @param block A block node. We pass the block, not the loop as we must - * start off with a block loop to find all proper uses. - * - * Returns non-zero, if the node n is not changed in the loop block - * belongs to or in inner loops of this blocks loop. */ -int is_loop_invariant(ir_node *n, ir_node *block) { - ir_loop *l = get_irn_loop(block); - ir_node *b = (is_Block(n)) ? n : get_nodes_block(n); - return !is_loop_variant(l, get_irn_loop(b)); +int is_loop_invariant(const ir_node *n, const ir_node *block) +{ + ir_loop *l = get_irn_loop(block); + const ir_node *b = is_Block(n) ? n : get_nodes_block(n); + return !is_loop_variant(l, get_irn_loop(b)); }