X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fopt%2Fscalar_replace.c;h=fb24fafbaf34fe5ca4bf7e0813e743d206c0162f;hb=f1a1a6092d9e4ebd9e22dd1c57d76ef8aeda74fc;hp=c8011d45cbd94d473f72fb0792a99d373b15be7b;hpb=8232963d5867b775e4251f6ba2bef69591042581;p=libfirm diff --git a/ir/opt/scalar_replace.c b/ir/opt/scalar_replace.c index c8011d45c..fb24fafba 100644 --- a/ir/opt/scalar_replace.c +++ b/ir/opt/scalar_replace.c @@ -2,19 +2,766 @@ * Project: libFIRM * File name: ir/opt/scalar_replace.c * Purpose: scalar replacement of arrays and compounds - * Author: Beyhan + * Author: Beyhan Veliev + * Modified by: Michael Beck * Created: * CVS-ID: $Id$ * Copyright: (c) 1998-2005 Universität Karlsruhe * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE. */ #ifdef HAVE_CONFIG_H -# include "config.h" +#include "config.h" #endif +#ifdef HAVE_ALLOCA_H +#include +#endif + +#ifdef HAVE_MALLOC_H +#include +#endif + +#ifdef HAVE_STRING_H +#include +#endif + +#include "scalar_replace.h" +#include "irflag_t.h" +#include "irouts.h" +#include "set.h" +#include "pset.h" +#include "array.h" +#include "tv.h" +#include "ircons_t.h" +#include "hashptr.h" +#include "irgwalk.h" +#include "irgmod.h" +#include "irnode_t.h" + +#define SET_VNUM(node, vnum) set_irn_link(node, (void *)vnum) +#define GET_VNUM(node) (unsigned)get_irn_link(node) + +/** + * A path element entry: it is either an entity + * or a tarval, because we evaluate only constant array + * accesses like a.b.c[8].d + */ +typedef union { + entity *ent; + tarval *tv; +} path_elem_t; + +/** + * An access path, used to assign value numbers + * to variables that will be scalar replaced + */ +typedef struct _path_t { + unsigned vnum; /**< the value number */ + unsigned path_len; /**< the length of the access path */ + path_elem_t path[1]; /**< the path */ +} path_t; + +typedef struct _scalars_t { + entity *ent; /**< A entity for scalar replacement. */ + type *ent_owner; /**< The owner of this entity. */ +} scalars_t; + + +/** + * Compare two pathes. + * + * @return 0 if they are identically + */ +static int path_cmp(const void *elt, const void *key, size_t size) +{ + const path_t *p1 = elt; + const path_t *p2 = key; + + /* we can use memcmp here, because identical tarvals should have identical addresses */ + return memcmp(p1->path, p2->path, p1->path_len * sizeof(p1->path[0])); +} + +/** + * Compare two elements of the scalars_t set. + * + * @return 0 if they are identically + */ +static int ent_cmp(const void *elt, const void *key, size_t size) +{ + const scalars_t *c1 = elt; + const scalars_t *c2 = key; + + return c1->ent != c2->ent; +} + +/** + * Calculate a hash value for a path. + */ +static unsigned path_hash(const path_t *path) +{ + unsigned hash = 0; + unsigned i; + + for (i = 0; i < path->path_len; ++i) + hash ^= (unsigned)path->path[i].ent; + + return hash >> 4; +} + +/** + * Returns non-zero, if all indeces of a Sel node are constants. + * + * @param sel the Sel node that will be checked + */ +static int is_const_sel(ir_node *sel) { + int i, n = get_Sel_n_indexs(sel); + + for (i = 0; i < n; ++i) { + ir_node *idx = get_Sel_index(sel, i); + + if (get_irn_op(idx) != op_Const) + return 0; + } + return 1; +} + +/** + * Returns non-zero, if the address of an entity + * represented by a Sel node (or it's successor Sels) is taken. + * + * @param sel the Sel node + */ +static int is_address_taken(ir_node *sel) +{ + int i, n; + + if (! is_const_sel(sel)) + return 1; + + n = get_irn_n_outs(sel); + for (i = 0; i < n; ++i) { + ir_node *succ = get_irn_out(sel, i); + + switch (get_irn_opcode(succ)) { + case iro_Load: + /* ok, we just load from that entity */ + break; + + case iro_Store: + /* check that Sel is not the Store's value */ + if (get_Store_value(succ) == sel) + return 1; + break; + + case iro_Sel: { + /* Check the Sel successor of Sel */ + int res = is_address_taken(succ); + + if (res) + return 1; + break; + } + + case iro_Call: + /* The address of an entity is given as a parameter. + * As long as we do not have analyses that can tell what + * is done with parameters, think is taken. + */ + return 1; + + default: + /* another op, the address is taken */ + return 1; + } + } + return 0; +} + +/** + * Link all leave Sels with the entity. + * + * @param ent the entity that will be scalar replaced + * @param sel a Sel node that selects some fields of this entity + */ +static void link_all_leave_sels(entity *ent, ir_node *sel) +{ + int i, n, flag = 1; + + n = get_irn_n_outs(sel); + for (i = 0; i < n; ++i) { + ir_node *succ = get_irn_out(sel, i); + + if (get_irn_op(succ) == op_Sel) { + link_all_leave_sels(ent, succ); + flag = 0; + } + } + + if (flag) { + /* if Sel nodes with memory inputs are used, a entity can be + * visited more than once causing a ring here, so we use the + * node flag to mark linked nodes + */ + if (irn_visited(sel)) + return; + + /* we know we are at a leave, because this function is only + * called if the address is NOT taken, so succ must be a Load + * or a Store node + */ + set_irn_link(sel, get_entity_link(ent)); + set_entity_link(ent, sel); + + mark_irn_visited(sel); + } +} + +/* we need a special address that serves as an address taken marker */ +static char _x; +static void *ADDRESS_TAKEN = &_x; + +/** + * Find possible scalar replacements. + * + * @param irg an IR graph + * + * This function finds variables on the (members of the) frame type + * that can be scalar replaced, because their address is never taken. + * If such a variable is found, it's entity link will hold a list of all + * Sel nodes, that selects the atomic fields of this entity. + * Otherwise, the link will be ADDRESS_TAKEN or NULL. + * + * @return non-zero if at least one entity could be replaced + * potentially + */ +static int find_possible_replacements(ir_graph *irg) +{ + ir_node *irg_frame = get_irg_frame(irg); + int i, n; + int res = 0; + + inc_irg_visited(irg); + + n = get_irn_n_outs(irg_frame); + + /* + * First, clear the link field of all interesting entities. + * Note that we did not rely on the fact that there is only + * one Sel node per entity, so we might access one entity + * more than once here. + * That's why we have need two loops. + */ + for (i = 0; i < n; ++i) { + ir_node *succ = get_irn_out(irg_frame, i); + + if (get_irn_op(succ) == op_Sel) { + entity *ent = get_Sel_entity(succ); + set_entity_link(ent, NULL); + } + } + + /* + * Check the ir_graph for Sel nodes. If the entity of Sel + * isn't a scalar replacement set the link of this entity + * equal ADDRESS_TAKEN. + */ + for (i = 0; i < n; ++i) { + ir_node *succ = get_irn_out(irg_frame, i); + + if (get_irn_op(succ) == op_Sel) { + entity *ent = get_Sel_entity(succ); + type *ent_type; + + if (get_entity_link(ent) == ADDRESS_TAKEN) + continue; + + ent_type = get_entity_type(ent); + + /* we can handle arrays, structs and atomic types yet */ + if (is_Array_type(ent_type) || is_Struct_type(ent_type) || is_atomic_type(ent_type)) { + if (is_address_taken(succ)) { + if (get_entity_link(ent)) /* killing one */ + --res; + set_entity_link(ent, ADDRESS_TAKEN); + } + else { + /* possible found one */ + if (get_entity_link(ent) == NULL) + ++res; + link_all_leave_sels(ent, succ); + } + } + } + } + + return res; +} + +/** + * Return a path from the Sel node sel to it's root. + * + * @param sel the Sel node + * @param len the length of the path so far + */ +static path_t *find_path(ir_node *sel, unsigned len) +{ + int pos, i, n; + path_t *res; + ir_node *pred = get_Sel_ptr(sel); + + /* the current Sel node will add some path elements */ + n = get_Sel_n_indexs(sel); + len += n + 1; + + if (get_irn_op(pred) != op_Sel) { + /* we found the root */ + + res = xmalloc(sizeof(*res) + (len - 1) * sizeof(res->path)); + res->path_len = len; + } + else + res = find_path(pred, len); + + pos = res->path_len - len; + + res->path[pos++].ent = get_Sel_entity(sel); + for (i = 0; i < n; ++i) { + ir_node *index = get_Sel_index(sel, i); + + res->path[pos++].tv = get_Const_tarval(index); + } + return res; +} + + +/** + * Allocate value numbers for the leaves + * in our found entities. + * + * @param sels a set that will contain all Sels that have a value number + * @param ent the entity that will be scalar replaced + * @param vnum the first value number we can assign + * @param modes a flexible array, containing all the modes of + * the value numbers. + * + * @return the next free value number + */ +static unsigned allocate_value_numbers(pset *sels, entity *ent, unsigned vnum, ir_mode ***modes) +{ + ir_node *sel, *next; + path_t *key, *path; + set *pathes = new_set(path_cmp, 8); + + /* visit all Sel nodes in the chain of the entity */ + for (sel = get_entity_link(ent); sel; sel = next) { + next = get_irn_link(sel); + + /* we must mark this sel for later */ + pset_insert_ptr(sels, sel); + + key = find_path(sel, 0); + path = set_find(pathes, key, sizeof(*key) + sizeof(key->path[0]) * key->path_len, path_hash(key)); + + if (path) + SET_VNUM(sel, path->vnum); + else { + unsigned i; + + key->vnum = vnum++; + + set_insert(pathes, key, sizeof(*key) + sizeof(key->path[0]) * key->path_len, path_hash(key)); + + SET_VNUM(sel, key->vnum); + ARR_EXTO(ir_mode *, *modes, (key->vnum + 15) & ~15); + + (*modes)[key->vnum] = get_type_mode(get_entity_type(get_Sel_entity(sel))); + + assert((*modes)[key->vnum] && "Value is not atomic"); + +#ifdef DEBUG_libfirm + /* Debug output */ + if (get_opt_scalar_replacement_verbose() && get_firm_verbosity() > 1) { + printf(" %s", get_entity_name(ent)); + for (i = 1; i < key->path_len; ++i) { + if (is_entity(key->path[i].ent)) + printf(".%s", get_entity_name(key->path[i].ent)); + else + printf("[%ld]", get_tarval_long(key->path[i].tv)); + } + printf(" = %u (%s)\n", (int)get_irn_link(sel), get_mode_name((*modes)[key->vnum])); + } +#endif /* DEBUG_libfirm */ + } + free(key); + } + + del_set(pathes); + set_entity_link(ent, NULL); + return vnum; +} + +/** + * A list entry for the fixing lists + */ +typedef struct _list_entry_t { + ir_node *node; /**< the node that must be fixed */ + unsigned vnum; /**< the value number of this node */ +} list_entry_t; + +/** + * environment for memory walker + */ +typedef struct _env_t { + struct obstack obst; /**< a obstack for the value blocks */ + int nvals; /**< number of values */ + ir_mode **modes; /**< the modes of the values */ + list_entry_t *fix_phis; /**< list of all Phi nodes that must be fixed */ + list_entry_t *fix_loads; /**< list of all Load nodes that must be fixed */ + pset *sels; /**< A set of all Sel nodes that have a value number */ +} env_t; + +/** + * Walker + */ +static void handle_first(ir_node *node, void *ctx) +{ + env_t *env = ctx; + ir_op *op = get_irn_op(node); + ir_node *adr, *block, *mem, *unk, **value_arr, **in; + unsigned vnum; + int i, j, n; + list_entry_t *l; + + if (op == op_Load) { + /* a load, check if we can resolve it */ + adr = get_Load_ptr(node); + + if (get_irn_op(adr) != op_Sel) + return; + + if (! pset_find_ptr(env->sels, adr)) + return; + + /* ok, we have a Load that will be replaced */ + vnum = GET_VNUM(adr); + + assert(vnum < (unsigned)env->nvals); + + block = get_nodes_block(node); + value_arr = get_irn_link(block); + + /* check, if we can replace this Load */ + if (value_arr[vnum]) { + mem = get_Load_mem(node); + + turn_into_tuple(node, pn_Load_max); + set_Tuple_pred(node, pn_Load_M, mem); + set_Tuple_pred(node, pn_Load_res, value_arr[vnum]); + set_Tuple_pred(node, pn_Load_X_except, new_Bad()); + } + else { + l = obstack_alloc(&env->obst, sizeof(*l)); + l->node = node; + l->vnum = vnum; + + set_irn_link(node, env->fix_loads); + env->fix_loads = l; + } + } + else if (op == op_Store) { + /* a Store always can be replaced */ + adr = get_Store_ptr(node); + + if (get_irn_op(adr) != op_Sel) + return; + + if (! pset_find_ptr(env->sels, adr)) + return; + + vnum = GET_VNUM(adr); + + assert(vnum < (unsigned)env->nvals); + + block = get_nodes_block(node); + value_arr = get_irn_link(block); + + value_arr[vnum] = get_Store_value(node); + + mem = get_Store_mem(node); + + turn_into_tuple(node, pn_Store_max); + set_Tuple_pred(node, pn_Store_M, mem); + set_Tuple_pred(node, pn_Store_X_except, new_Bad()); + } + else if (op == op_Phi && get_irn_mode(node) == mode_M) { + /* + * found a memory Phi: Here, we must create new Phi nodes + */ + block = get_nodes_block(node); + value_arr = get_irn_link(block); + + n = get_Block_n_cfgpreds(block); + + in = alloca(sizeof(*in) * n); + + for (i = env->nvals - 1; i >= 0; --i) { + unk = new_Unknown(env->modes[i]); + for (j = n - 1; j >= 0; --j) + in[j] = unk; + + value_arr[i] = new_r_Phi(current_ir_graph, block, n, in, env->modes[i]); + + l = obstack_alloc(&env->obst, sizeof(*l)); + l->node = value_arr[i]; + l->vnum = i; + + set_irn_link(value_arr[i], env->fix_phis); + env->fix_phis = l; + } + } +} + +/** + * Walker: allocate the value array for every block. + */ +static void alloc_value_arr(ir_node *block, void *ctx) +{ + env_t *env = ctx; + ir_node **var_arr = obstack_alloc(&env->obst, sizeof(*var_arr) * env->nvals); + + /* the value array is empty at start */ + memset(var_arr, 0, sizeof(*var_arr) * env->nvals); + set_irn_link(block, var_arr); +} + +/** + * searches through blocks beginning from block for value + * vnum and return it. + */ +static ir_node *find_value(ir_node *block, unsigned vnum) +{ + ir_node **value_arr; + int i; + ir_node *res; + + if (Block_not_block_visited(block)) { + mark_Block_block_visited(block); + + value_arr = get_irn_link(block); + + if (value_arr[vnum]) + return value_arr[vnum]; + + for (i = get_Block_n_cfgpreds(block) - 1; i >= 0; --i) { + ir_node *pred = get_Block_cfgpred(block, i); + + res = find_value(get_nodes_block(pred), vnum); + if (res) + return res; + } + } + return NULL; +} + +/** + * fix the Phi list + */ +static void fix_phis(env_t *env) +{ + list_entry_t *l; + ir_node *phi, *block, *pred, *val; + int i; + + for (l = env->fix_phis; l; l = get_irn_link(phi)) { + phi = l->node; + + block = get_nodes_block(phi); + for (i = get_irn_arity(phi) - 1; i >= 0; --i) { + pred = get_Block_cfgpred(block, i); + pred = get_nodes_block(pred); + + inc_irg_block_visited(current_ir_graph); + val = find_value(pred, l->vnum); + + if (val) + set_irn_n(phi, i, val); + } + } +} + +/** + * fix the Load list + */ +static void fix_loads(env_t *env) +{ + list_entry_t *l; + ir_node *load, *block, *pred, *val, *mem; + int i; + + for (l = env->fix_loads; l; l = get_irn_link(load)) { + load = l->node; + + block = get_nodes_block(load); + for (i = get_Block_n_cfgpreds(block) - 1; i >= 0; --i) { + pred = get_Block_cfgpred(block, i); + pred = get_nodes_block(pred); + + inc_irg_block_visited(current_ir_graph); + val = find_value(pred, l->vnum); + + if (val) + break; + } + + if (! val) { + /* access of an uninitialized value */ + val = new_Unknown(env->modes[l->vnum]); + } + + mem = get_Load_mem(load); + + turn_into_tuple(load, pn_Load_max); + set_Tuple_pred(load, pn_Load_M, mem); + set_Tuple_pred(load, pn_Load_res, val); + set_Tuple_pred(load, pn_Load_X_except, new_Bad()); + } +} + +/** + * Make scalar replacement. + * + * @param sels A set containing all Sel nodes that have a value number + * @param nvals The number of scalars. + * @param modes A flexible array, containing all the modes of + * the value numbers. + */ +static void do_scalar_replacements(pset *sels, int nvals, ir_mode **modes) +{ + env_t env; + + obstack_init(&env.obst); + env.nvals = nvals; + env.modes = modes; + env.fix_phis = NULL; + env.fix_loads = NULL; + env.sels = sels; + + /* first step: allocate the value arrays for every block */ + irg_block_walk_graph(current_ir_graph, NULL, alloc_value_arr, &env); + + /* + * second step: walk over the graph blockwise in topological order + * and fill the array as much as possible. + */ + irg_walk_blkwise_graph(current_ir_graph, NULL, handle_first, &env); + + /* third, fix the list of Phis, then the list of Loads */ + fix_phis(&env); + fix_loads(&env); + + obstack_free(&env.obst, NULL); +} + /* - * find possible scalar replacements + * Find possible scalar replacements + * + * @param irg The current ir graph. */ -void find_scalar_replacements(irgraph *irg) +void scalar_replacement_opt(ir_graph *irg) { + unsigned nvals; + int i; + scalars_t key, *value; + ir_node *irg_frame; + ir_mode **modes; + set *set_ent; + pset *sels; + type *ent_type; + ir_graph *rem; + + if (! get_opt_scalar_replacement()) + return; + + rem = current_ir_graph; + + /* Call algorithm that computes the out edges */ + if (get_irg_outs_state(irg) != outs_consistent) + compute_irg_outs(irg); + + /* Find possible scalar replacements */ + if (find_possible_replacements(irg)) { + + if (get_opt_scalar_replacement_verbose()) { + printf("Scalar Replacement: %s\n", get_entity_name(get_irg_entity(irg))); + } + + /* Insert in set the scalar replacements. */ + irg_frame = get_irg_frame(irg); + nvals = 0; + modes = NEW_ARR_F(ir_mode *, 16); + set_ent = new_set(ent_cmp, 8); + sels = pset_new_ptr(8); + + for (i = 0 ; i < get_irn_n_outs(irg_frame); i++) { + ir_node *succ = get_irn_out(irg_frame, i); + + if (get_irn_op(succ) == op_Sel) { + entity *ent = get_Sel_entity(succ); + + if (get_entity_link(ent) == NULL || get_entity_link(ent) == ADDRESS_TAKEN) + continue; + + ent_type = get_entity_type(ent); + + key.ent = ent; + key.ent_owner = get_entity_owner(ent); + set_insert(set_ent, &key, sizeof(key), HASH_PTR(key.ent)); + + if (get_opt_scalar_replacement_verbose()) { + if (is_Array_type(ent_type)) { + printf(" found array %s\n", get_entity_name(ent)); + } + else if (is_Struct_type(ent_type)) { + printf(" found struct %s\n", get_entity_name(ent)); + } + else if (is_atomic_type(ent_type)) + printf(" found atomic value %s\n", get_entity_name(ent)); + else { + assert(0 && "Neither an array nor a struct or atomic value"); + } + } + + nvals = allocate_value_numbers(sels, ent, nvals, &modes); + } + } + + if (get_opt_scalar_replacement_verbose()) { + printf(" %u values will be needed\n", nvals); + } + + /* If scalars were found. */ + if (nvals) { + do_scalar_replacements(sels, nvals, modes); + + for (value = set_first(set_ent); value; value = set_next(set_ent)) { + remove_class_member(value->ent_owner, value->ent); + } + } + + del_pset(sels); + del_set(set_ent); + DEL_ARR_F(modes); + + if (nvals) { + /* + * We changed the graph, but did NOT introduce new blocks + * neither changed control flow, cf-backedges should be still + * consistent. + */ + set_irg_outs_inconsistent(irg); + set_irg_loopinfo_inconsistent(irg); + } + } + + current_ir_graph = rem; }