X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fopt%2Fscalar_replace.c;h=09e70986ce7c40f4893705aa2a2313f4d143b8fd;hb=34e3b8d50bce639e760da7233524a4db85c80290;hp=c8011d45cbd94d473f72fb0792a99d373b15be7b;hpb=8232963d5867b775e4251f6ba2bef69591042581;p=libfirm diff --git a/ir/opt/scalar_replace.c b/ir/opt/scalar_replace.c index c8011d45c..09e70986c 100644 --- a/ir/opt/scalar_replace.c +++ b/ir/opt/scalar_replace.c @@ -1,20 +1,766 @@ /* - * Project: libFIRM - * File name: ir/opt/scalar_replace.c - * Purpose: scalar replacement of arrays and compounds - * Author: Beyhan - * 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" -#endif + * This file is part of libFirm. + * Copyright (C) 2012 University of Karlsruhe. + */ + +/** + * @file + * @brief Scalar replacement of compounds. + * @author Beyhan Veliev, Michael Beck + */ +#include "config.h" + +#include +#include + +#include "iroptimize.h" +#include "scalar_replace.h" +#include "opt_init.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" +#include "irpass.h" +#include "util.h" +#include "xmalloc.h" +#include "debug.h" +#include "error.h" + +static unsigned get_vnum(const ir_node *node) +{ + return (unsigned)PTR_TO_INT(get_irn_link(node)); +} + +static void set_vnum(ir_node *node, unsigned vnum) +{ + set_irn_link(node, INT_TO_PTR(vnum)); +} + +/** + * 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 { + ir_entity *ent; + ir_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. */ + size_t path_len; /**< The length of the access path. */ + path_elem_t path[1]; /**< The path. */ +} path_t; + +/** The size of a path in bytes. */ +static size_t path_size(path_t *p) +{ + return sizeof(*p) + sizeof(p->path[0]) * (p->path_len-1); +} + +typedef struct scalars_t { + ir_entity *ent; /**< A entity for scalar replacement. */ +} scalars_t; + +DEBUG_ONLY(static firm_dbg_module_t *dbg;) + +/** + * 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 = (const path_t*)elt; + const path_t *p2 = (const path_t*)key; + (void) size; + + /* 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 = (const scalars_t*)elt; + const scalars_t *c2 = (const scalars_t*)key; + (void) size; + + 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)PTR_TO_INT(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 bool 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 (!is_Const(idx)) + return false; + } + return true; +} + +/** + * Check the mode of a Load/Store with the mode of the entity + * that is accessed. + * If the mode of the entity and the Load/Store mode do not match, we + * have the bad reinterpret case: + * + * int i; + * char b = *(char *)&i; + * + * We do NOT count this as one value and return address_taken + * in that case. + * However, we support an often used case. If the mode is two-complement + * we allow casts between signed/unsigned. + * + * @param mode the mode of the Load/Store + * @param ent_mode the mode of the accessed entity + */ +static bool check_load_store_mode(ir_mode *mode, ir_mode *ent_mode) +{ + if (ent_mode != mode) { + if (ent_mode == NULL || + get_mode_size_bits(ent_mode) != get_mode_size_bits(mode) || + get_mode_arithmetic(ent_mode) != irma_twos_complement || + get_mode_arithmetic(mode) != irma_twos_complement) + return false; + } + return true; +} + +/* + * Returns non-zero, if the address of an entity + * represented by a Sel node (or its successor Sels) is taken. + */ +bool is_address_taken(ir_node *sel) +{ + int input_nr; + ir_mode *emode, *mode; + ir_node *value; + ir_entity *ent; + + if (! is_const_sel(sel)) + return true; + + for (unsigned i = get_irn_n_outs(sel); i-- > 0; ) { + ir_node *succ = get_irn_out(sel, i); + + switch (get_irn_opcode(succ)) { + case iro_Load: + /* do not remove volatile variables */ + if (get_Load_volatility(succ) == volatility_is_volatile) + return true; + /* check if this load is not a hidden conversion */ + mode = get_Load_mode(succ); + ent = get_Sel_entity(sel); + emode = get_type_mode(get_entity_type(ent)); + if (! check_load_store_mode(mode, emode)) + return true; + break; + + case iro_Store: + /* check that Sel is not the Store's value */ + value = get_Store_value(succ); + if (value == sel) + return true; + /* do not remove volatile variables */ + if (get_Store_volatility(succ) == volatility_is_volatile) + return true; + /* check if this Store is not a hidden conversion */ + mode = get_irn_mode(value); + ent = get_Sel_entity(sel); + emode = get_type_mode(get_entity_type(ent)); + if (! check_load_store_mode(mode, emode)) + return true; + break; + + case iro_Sel: { + int res; + ir_entity *entity = get_Sel_entity(succ); + /* we can't handle unions correctly yet -> address taken */ + if (is_Union_type(get_entity_owner(entity))) + return true; + + /* Check the Sel successor of Sel */ + res = is_address_taken(succ); + if (res) + return true; + 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. + * One special case: If the Call type tells that it's a + * value parameter, the address is NOT taken. + */ + return true; + + case iro_Id: { + int res = is_address_taken(succ); + if (res) + return true; + break; + } + + case iro_Tuple: + /* Non-optimized Tuple, happens in inlining */ + for (input_nr = get_Tuple_n_preds(succ) - 1; input_nr >= 0; --input_nr) { + ir_node *pred = get_Tuple_pred(succ, input_nr); + + if (pred == sel) { + /* we found one input */ + for (unsigned k = get_irn_n_outs(succ); k-- > 0; ) { + ir_node *proj = get_irn_out(succ, k); + + if (is_Proj(proj) && get_Proj_proj(proj) == input_nr) { + int res = is_address_taken(proj); + if (res) + return true; + } + } + } + } + break; + + default: + /* another op, the address is taken */ + return true; + } + } + return false; +} + +/** + * 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 bool link_all_leave_sels(ir_entity *ent, ir_node *sel) +{ + bool is_leave = true; + + for (unsigned i = get_irn_n_outs(sel); i-- > 0; ) { + ir_node *succ = get_irn_out(sel, i); + + if (is_Sel(succ)) { + /* the current leave has further Sel's, no leave */ + is_leave = false; + link_all_leave_sels(ent, succ); + } else if (is_Id(succ)) { + is_leave &= link_all_leave_sels(ent, succ); + } + } + + if (is_leave) { + /* beware of Id's */ + sel = skip_Id(sel); + + /* we know we are at a leave, because this function is only + * called if the address is NOT taken, so sel's successor(s) + * must be Loads or Stores + */ + set_irn_link(sel, get_entity_link(ent)); + set_entity_link(ent, sel); + } + return is_leave; +} + +/* 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, its 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; + ir_type *frame_tp; + size_t mem_idx; + long static_link_arg; + int res = 0; + + /* + * First, clear the link field of all interesting entities. + */ + frame_tp = get_irg_frame_type(irg); + for (mem_idx = get_class_n_members(frame_tp); mem_idx > 0;) { + ir_entity *ent = get_class_member(frame_tp, --mem_idx); + set_entity_link(ent, NULL); + } + + /* check for inner functions: + * FIXME: need a way to get the argument position for the static link */ + static_link_arg = 0; + for (mem_idx = get_class_n_members(frame_tp); mem_idx > 0;) { + ir_entity *ent = get_class_member(frame_tp, --mem_idx); + if (is_method_entity(ent)) { + ir_graph *inner_irg = get_entity_irg(ent); + ir_node *args; + + assure_irg_properties(inner_irg, IR_GRAPH_PROPERTY_CONSISTENT_OUTS); + args = get_irg_args(inner_irg); + for (unsigned j = get_irn_n_outs(args); j-- > 0; ) { + ir_node *arg = get_irn_out(args, j); + + if (get_Proj_proj(arg) == static_link_arg) { + for (unsigned k = get_irn_n_outs(arg); k-- > 0; ) { + ir_node *succ = get_irn_out(arg, k); + + if (is_Sel(succ)) { + ir_entity *ent = get_Sel_entity(succ); + + if (get_entity_owner(ent) == frame_tp) { + /* found an access to the outer frame */ + set_entity_link(ent, ADDRESS_TAKEN); + } + } + } + } + } + } + } + + /* + * 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. + */ + irg_frame = get_irg_frame(irg); + for (unsigned i = get_irn_n_outs(irg_frame); i-- > 0; ) { + ir_node *succ = get_irn_out(irg_frame, i); + + if (is_Sel(succ)) { + ir_entity *ent = get_Sel_entity(succ); + ir_type *ent_type; + + /* we are only interested in entities on the frame, NOT + on the value type */ + if (get_entity_owner(ent) != frame_tp) + continue; + + 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)) { + /* killing one */ + if (get_entity_link(ent)) + --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 its root. + * + * @param sel the Sel node + * @param len the length of the path so far + */ +static path_t *find_path(ir_node *sel, size_t len) +{ + size_t pos; + int 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 (! is_Sel(pred)) { + /* we found the root */ + res = XMALLOCF(path_t, path, len); + res->path_len = len; + } else + res = find_path(pred, len); + + assert(len <= res->path_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, ir_entity *ent, unsigned vnum, ir_mode ***modes) +{ + ir_node *sel, *next; + path_t *key, *path; + set *pathes = new_set(path_cmp, 8); + + DB((dbg, SET_LEVEL_3, " Visiting Sel nodes of entity %+F\n", ent)); + /* visit all Sel nodes in the chain of the entity */ + for (sel = (ir_node*)get_entity_link(ent); sel != NULL; sel = next) { + next = (ir_node*)get_irn_link(sel); + + /* we must mark this sel for later */ + pset_insert_ptr(sels, sel); + + key = find_path(sel, 0); + path = set_find(path_t, pathes, key, path_size(key), path_hash(key)); + + if (path) { + set_vnum(sel, path->vnum); + DB((dbg, SET_LEVEL_3, " %+F represents value %u\n", sel, path->vnum)); + } else { + key->vnum = vnum++; + + (void)set_insert(path_t, pathes, key, path_size(key), path_hash(key)); + + set_vnum(sel, key->vnum); + DB((dbg, SET_LEVEL_3, " %+F represents value %u\n", 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 */ + { + unsigned i; + DB((dbg, SET_LEVEL_2, " %s", get_entity_name(key->path[0].ent))); + for (i = 1; i < key->path_len; ++i) { + if (is_entity(key->path[i].ent)) + DB((dbg, SET_LEVEL_2, ".%s", get_entity_name(key->path[i].ent))); + else + DB((dbg, SET_LEVEL_2, "[%ld]", get_tarval_long(key->path[i].tv))); + } + DB((dbg, SET_LEVEL_2, " = %u (%s)\n", PTR_TO_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; +} + +/** + * environment for memory walker + */ +typedef struct env_t { + unsigned nvals; /**< number of values */ + ir_mode **modes; /**< the modes of the values */ + pset *sels; /**< A set of all Sel nodes that have a value number */ +} env_t; + +/** + * topological post-walker. + */ +static void walker(ir_node *node, void *ctx) +{ + env_t *env = (env_t*)ctx; + ir_graph *irg = get_irn_irg(node); + ir_node *addr, *block, *mem, *val; + ir_mode *mode; + unsigned vnum; + + if (is_Load(node)) { + /* a load, check if we can resolve it */ + addr = get_Load_ptr(node); + + DB((dbg, SET_LEVEL_3, " checking %+F for replacement ", node)); + if (! is_Sel(addr)) { + DB((dbg, SET_LEVEL_3, "no Sel input (%+F)\n", addr)); + return; + } + + if (! pset_find_ptr(env->sels, addr)) { + DB((dbg, SET_LEVEL_3, "Sel %+F has no VNUM\n", addr)); + return; + } + + /* ok, we have a Load that will be replaced */ + vnum = get_vnum(addr); + assert(vnum < env->nvals); + + DB((dbg, SET_LEVEL_3, "replacing by value %u\n", vnum)); + + block = get_nodes_block(node); + set_cur_block(block); + + /* check, if we can replace this Load */ + val = get_value(vnum, env->modes[vnum]); + + /* Beware: A Load can contain a hidden conversion in Firm. + This happens for instance in the following code: + + int i; + unsigned j = *(unsigned *)&i; + + Handle this here. */ + mode = get_Load_mode(node); + if (mode != get_irn_mode(val)) + val = new_rd_Conv(get_irn_dbg_info(node), block, val, mode); + + mem = get_Load_mem(node); + ir_node *const in[] = { + [pn_Load_M] = mem, + [pn_Load_res] = val, + [pn_Load_X_regular] = new_r_Jmp(block), + [pn_Load_X_except] = new_r_Bad(irg, mode_X), + }; + turn_into_tuple(node, ARRAY_SIZE(in), in); + } else if (is_Store(node)) { + DB((dbg, SET_LEVEL_3, " checking %+F for replacement ", node)); + + /* a Store always can be replaced */ + addr = get_Store_ptr(node); + + if (! is_Sel(addr)) { + DB((dbg, SET_LEVEL_3, "no Sel input (%+F)\n", addr)); + return; + } + + if (! pset_find_ptr(env->sels, addr)) { + DB((dbg, SET_LEVEL_3, "Sel %+F has no VNUM\n", addr)); + return; + } + + vnum = get_vnum(addr); + assert(vnum < env->nvals); + + DB((dbg, SET_LEVEL_3, "replacing by value %u\n", vnum)); + + block = get_nodes_block(node); + set_cur_block(block); + + /* Beware: A Store can contain a hidden conversion in Firm. */ + val = get_Store_value(node); + if (get_irn_mode(val) != env->modes[vnum]) + val = new_rd_Conv(get_irn_dbg_info(node), block, val, env->modes[vnum]); + + set_value(vnum, val); + + mem = get_Store_mem(node); + ir_node *const in[] = { + [pn_Store_M] = mem, + [pn_Store_X_regular] = new_r_Jmp(block), + [pn_Store_X_except] = new_r_Bad(irg, mode_X), + }; + turn_into_tuple(node, ARRAY_SIZE(in), in); + } +} + +/** + * 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(ir_graph *irg, pset *sels, unsigned nvals, + ir_mode **modes) +{ + env_t env; + + ssa_cons_start(irg, (int)nvals); + + env.nvals = nvals; + env.modes = modes; + env.sels = sels; + + /* + * second step: walk over the graph blockwise in topological order + * and fill the array as much as possible. + */ + DB((dbg, SET_LEVEL_3, "Substituting Loads and Stores in %+F\n", irg)); + irg_walk_blkwise_graph(irg, NULL, walker, &env); + + ssa_cons_finish(irg); +} /* - * 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; + scalars_t key; + ir_node *irg_frame; + ir_mode **modes; + set *set_ent; + pset *sels; + ir_type *ent_type, *frame_tp; + + assure_irg_properties(irg, + IR_GRAPH_PROPERTY_NO_UNREACHABLE_CODE + | IR_GRAPH_PROPERTY_CONSISTENT_OUTS); + + /* we use the link field to store the VNUM */ + ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK); + irp_reserve_resources(irp, IRP_RESOURCE_ENTITY_LINK); + + /* Find possible scalar replacements */ + if (find_possible_replacements(irg)) { + DB((dbg, SET_LEVEL_1, "Scalar Replacement: %+F\n", 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); + frame_tp = get_irg_frame_type(irg); + + for (unsigned i = get_irn_n_outs(irg_frame); i-- > 0; ) { + ir_node *succ = get_irn_out(irg_frame, i); + + if (is_Sel(succ)) { + ir_entity *ent = get_Sel_entity(succ); + + /* we are only interested in entities on the frame, NOT + parameters */ + if (get_entity_owner(ent) != frame_tp + || is_parameter_entity(ent)) + continue; + + if (get_entity_link(ent) == NULL || get_entity_link(ent) == ADDRESS_TAKEN) + continue; + + ent_type = get_entity_type(ent); + + key.ent = ent; + (void)set_insert(scalars_t, set_ent, &key, sizeof(key), hash_ptr(key.ent)); + +#ifdef DEBUG_libfirm + if (is_Array_type(ent_type)) { + DB((dbg, SET_LEVEL_1, " found array %s\n", get_entity_name(ent))); + } else if (is_Struct_type(ent_type)) { + DB((dbg, SET_LEVEL_1, " found struct %s\n", get_entity_name(ent))); + } else if (is_atomic_type(ent_type)) + DB((dbg, SET_LEVEL_1, " found atomic value %s\n", get_entity_name(ent))); + else { + panic("Neither an array nor a struct or atomic value found in scalar replace"); + } +#endif /* DEBUG_libfirm */ + + nvals = allocate_value_numbers(sels, ent, nvals, &modes); + } + } + + DB((dbg, SET_LEVEL_1, " %u values will be needed\n", nvals)); + + /* If scalars were found. */ + if (nvals > 0) { + do_scalar_replacements(irg, sels, nvals, modes); + + foreach_set(set_ent, scalars_t, value) { + free_entity(value->ent); + } + + /* + * We changed the graph, but did NOT introduce new blocks + * neither changed control flow, cf-backedges should be still + * consistent. + */ + } + del_pset(sels); + del_set(set_ent); + DEL_ARR_F(modes); + } + + ir_free_resources(irg, IR_RESOURCE_IRN_LINK); + irp_free_resources(irp, IRP_RESOURCE_ENTITY_LINK); + + confirm_irg_properties(irg, IR_GRAPH_PROPERTIES_NONE); +} + +ir_graph_pass_t *scalar_replacement_opt_pass(const char *name) +{ + return def_graph_pass(name ? name : "scalar_rep", scalar_replacement_opt); +} + +void firm_init_scalar_replace(void) { + FIRM_DBG_REGISTER(dbg, "firm.opt.scalar_replace"); }