X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fopt%2Fldstopt.c;h=d792260b51e0cb116192141acdd3385c630230bf;hb=9bea3d74018e82f653deadff88f8626fd1a6557d;hp=0ea39e832bea3dec960c1a237b3deac72a7433b9;hpb=63141f8672b7c7419784f414136ce7d13f898fa4;p=libfirm diff --git a/ir/opt/ldstopt.c b/ir/opt/ldstopt.c index 0ea39e832..d792260b5 100644 --- a/ir/opt/ldstopt.c +++ b/ir/opt/ldstopt.c @@ -8,6 +8,20 @@ * Copyright: (c) 1998-2004 Universität Karlsruhe * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE. */ +#ifdef HAVE_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 "irnode_t.h" # include "irgraph_t.h" # include "irmode_t.h" @@ -21,7 +35,7 @@ # include "iropt_dbg.h" # include "irflag_t.h" # include "array.h" -# include "firmstat.h" +# include "irhooks.h" #undef IMAX #define IMAX(a,b) ((a) > (b) ? (a) : (b)) @@ -36,13 +50,21 @@ typedef struct _walk_env_t { int changes; } walk_env_t; +/** + * flags for Load/Store + */ +enum ldst_flags_t { + LDST_VISITED = 1 /**< if set, this Load/Store is already visited */ +}; + /** * a Load/Store info */ typedef struct _ldst_info_t { - ir_node *projs[MAX_PROJ]; /**< list of Proj's of this node */ - ir_node *exc_block; /**< the exception block if available */ - int exc_idx; /**< predecessor index in the exception block */ + ir_node *projs[MAX_PROJ]; /**< list of Proj's of this node */ + ir_node *exc_block; /**< the exception block if available */ + int exc_idx; /**< predecessor index in the exception block */ + unsigned flags; /**< flags */ } ldst_info_t; /** @@ -134,6 +156,9 @@ static int update_exc(ldst_info_t *info, ir_node *block, int pos) return 0; } +#define get_irn_out_n(node) (unsigned)get_irn_link(node) +#define set_irn_out_n(node, n) set_irn_link(adr, (void *)(n)) + /** * walker, collects all Load/Store/Proj nodes * @@ -141,20 +166,44 @@ static int update_exc(ldst_info_t *info, ir_node *block, int pos) */ static void collect_nodes(ir_node *node, void *env) { + ir_op *op = get_irn_op(node); ir_node *pred; ldst_info_t *ldst_info; walk_env_t *wenv = env; - if (get_irn_op(node) == op_Proj) { + if (op == op_Proj) { + ir_node *adr; + ir_op *op; + pred = get_Proj_pred(node); + op = get_irn_op(pred); + + if (op == op_Load) { + ldst_info = get_ldst_info(pred, wenv); + + wenv->changes |= update_projs(ldst_info, node); + + if ((ldst_info->flags & LDST_VISITED) == 0) { + adr = get_Load_ptr(pred); + set_irn_out_n(adr, get_irn_out_n(adr) + 1); - if (get_irn_op(pred) == op_Load || get_irn_op(pred) == op_Store) { + ldst_info->flags |= LDST_VISITED; + } + } + else if (op == op_Store) { ldst_info = get_ldst_info(pred, wenv); wenv->changes |= update_projs(ldst_info, node); + + if ((ldst_info->flags & LDST_VISITED) == 0) { + adr = get_Store_ptr(pred); + set_irn_out_n(adr, get_irn_out_n(adr) + 1); + + ldst_info->flags |= LDST_VISITED; + } } } - else if (get_irn_op(node) == op_Block) { /* check, if it's an exception block */ + else if (op == op_Block) { /* check, if it's an exception block */ int i, n; for (i = 0, n = get_Block_n_cfgpreds(node); i < n; ++i) { @@ -184,6 +233,60 @@ static void collect_nodes(ir_node *node, void *env) } } +/** + * returns a entity if the address ptr points to a constant one. + */ +static entity *find_constant_entity(ir_node *ptr) +{ + for (;;) { + ir_op *op = get_irn_op(ptr); + + if (op == op_SymConst && (get_SymConst_kind(ptr) == symconst_addr_ent)) { + return get_SymConst_entity(ptr); + } + else if (op == op_Sel) { + entity *ent = get_Sel_entity(ptr); + type *tp = get_entity_owner(ent); + + if (is_Array_type(tp)) { + /* check bounds */ + int i, n; + + for (i = 0, n = get_Sel_n_indexs(ptr); i < n; ++i) { + ir_node *bound; + tarval *tlower, *tupper; + ir_node *index = get_Sel_index(ptr, i); + tarval *tv = computed_value(index); + + /* check if the index is constant */ + if (tv == tarval_bad) + return NULL; + + bound = get_array_lower_bound(tp, i); + tlower = computed_value(bound); + bound = get_array_upper_bound(tp, i); + tupper = computed_value(bound); + + if (tlower == tarval_bad || tupper == tarval_bad) + return NULL; + + if (tarval_cmp(tv, tlower) & pn_Cmp_Lt) + return NULL; + if (tarval_cmp(tupper, tv) & pn_Cmp_Lt) + return NULL; + + /* ok, bounds check finished */ + } + } + + /* try next */ + ptr = get_Sel_ptr(ptr); + } + else + return NULL; + } +} + /** * optimize a Load */ @@ -192,86 +295,204 @@ static int optimize_load(ir_node *load) ldst_info_t *info = get_irn_link(load); ir_mode *load_mode = get_Load_mode(load); ir_node *pred, *mem, *ptr; - int res = 1; + entity *ent; + int res = 0; - if (get_Load_volatility(load) == volatility_is_volatile) - return 0; + /* the address of the load to be optimized */ + ptr = get_Load_ptr(load); /* - * BEWARE: one might think that checking the modes is useless, because - * if the pointers are identical, they refer to the same object. - * This is only true in strong typed languages, not is C were the following - * is possible a = *(type1 *)p; b = *(type2 *)p ... + * Check if we can remove the exception form a Load: + * this can be done, if the address is from an Sel(Alloc) and + * the Sel type is a subtype of the alloc type. + * + * This optimizes some often used OO constructs, + * like x = new O; x->t; */ + if (info->projs[pn_Load_X_except]) { + if (get_irn_op(ptr) == op_Sel) { + ir_node *mem = get_Sel_mem(ptr); + + if (get_irn_op(mem) == op_Alloc) { + /* ok, check the types */ + entity *ent = get_Sel_entity(ptr); + type *s_type = get_entity_type(ent); + type *a_type = get_Alloc_type(mem); + + if (is_subclass_of(s_type, a_type)) { + /* ok, condition met: there can't be an exception because + * alloc guarantees that enough memory was allocated */ + + exchange(info->projs[pn_Load_X_except], new_Bad()); + info->projs[pn_Load_X_except] = NULL; + } + } + } + else if (get_irn_op(ptr) == op_Alloc) { + /* simple case: a direct load after an Alloc. Firm Alloc throw + * an exception in case of out-of-memory. So, there is no way for an + * exception in this load. + * This code is constructed by the "exception lowering" in the Jack compiler. + */ + exchange(info->projs[pn_Load_X_except], new_Bad()); + info->projs[pn_Load_X_except] = NULL; + } + } - ptr = get_Load_ptr(load); - mem = get_Load_mem(load); - pred = skip_Proj(mem); + /* do NOT touch volatile loads for now */ + if (get_Load_volatility(load) == volatility_is_volatile) + return 0; if (! info->projs[pn_Load_res] && ! info->projs[pn_Load_X_except]) { /* a Load which value is neither used nor exception checked, remove it */ + mem = get_Load_mem(load); exchange(info->projs[pn_Load_M], mem); - res = 1; + + return 1; } - else if (get_irn_op(pred) == op_Store && get_Store_ptr(pred) == ptr && - get_irn_mode(get_Store_value(pred)) == load_mode) { - /* - * a load immediately after a store -- a read after write. - * We may remove the Load, if it does not have an exception handler - * OR they are in the same block. In the latter case the Load cannot - * throw an exception when the previous Store was quiet. - */ - if (! info->projs[pn_Load_X_except] || get_nodes_block(load) == get_nodes_block(pred)) { - DBG_OPT_RAW(pred, load); - exchange( info->projs[pn_Load_res], get_Store_value(pred) ); - if (info->projs[pn_Load_M]) - exchange(info->projs[pn_Load_M], mem); + /* the mem of the Load. Must still be returned after optimization */ + mem = get_Load_mem(load); + + /* check if we can determine the entity that will be loaded */ + ent = find_constant_entity(ptr); + if (ent) { + if ((allocation_static == get_entity_allocation(ent)) && + (visibility_external_allocated != get_entity_visibility(ent))) { + /* a static allocation that is not external: there should be NO exception + * when loading. */ + + /* no exception, clear the info field as it might be checked later again */ + if (info->projs[pn_Load_X_except]) { + exchange(info->projs[pn_Load_X_except], new_Bad()); + info->projs[pn_Load_X_except] = NULL; + } + + if (variability_constant == get_entity_variability(ent) + && is_atomic_entity(ent)) { /* Might not be atomic after + lowering of Sels. In this + case we could also load, but + it's more complicated. */ + /* more simpler case: we load the content of a constant value: + * replace it by the constant itself + */ + + /* no memory */ + if (info->projs[pn_Load_M]) + exchange(info->projs[pn_Load_M], mem); + + /* no result :-) */ + if (info->projs[pn_Load_res]) { + if (is_atomic_entity(ent)) { + ir_node *c = copy_const_value(get_atomic_ent_value(ent)); + + DBG_OPT_RC(load, c); + exchange(info->projs[pn_Load_res], c); + + return 1; + } + } + } + else if (variability_constant == get_entity_variability(ent)) { + printf(">>>>>>>>>>>>> Found access to constant entity %s in function %s\n", get_entity_name(ent), + get_entity_name(get_irg_entity(current_ir_graph))); + } - /* no exception */ - if (info->projs[pn_Load_X_except]) - exchange( info->projs[pn_Load_X_except], new_Bad()); + /* we changed the irg, but try further */ res = 1; } } - else if (get_irn_op(pred) == op_Load && get_Load_ptr(pred) == ptr && - get_Load_mode(pred) == load_mode) { + + /* Check, if the address of this load is used more than once. + * If not, this load cannot be removed in any case. */ + if (get_irn_out_n(ptr) <= 1) + return 0; + + /* follow the memory chain as long as there are only Loads */ + for (pred = skip_Proj(mem); ; pred = skip_Proj(get_Load_mem(pred))) { + /* - * a load immediately after a load -- a read after read. - * We may remove the second Load, if it does not have an exception handler - * OR they are in the same block. In the later case the Load cannot - * throw an exception when the previous Load was quiet. + * BEWARE: one might think that checking the modes is useless, because + * if the pointers are identical, they refer to the same object. + * This is only true in strong typed languages, not is C were the following + * is possible a = *(type1 *)p; b = *(type2 *)p ... */ - if (! info->projs[pn_Load_X_except] || get_nodes_block(load) == get_nodes_block(pred)) { - ldst_info_t *pred_info = get_irn_link(pred); - DBG_OPT_RAR(pred, load); + if (get_irn_op(pred) == op_Store && get_Store_ptr(pred) == ptr && + get_irn_mode(get_Store_value(pred)) == load_mode) { + ldst_info_t *pred_info = get_irn_link(pred); - if (pred_info->projs[pn_Load_res]) { - /* we need a data proj from the previous load for this optimization */ - exchange( info->projs[pn_Load_res], pred_info->projs[pn_Load_res] ); - if (info->projs[pn_Load_M]) - exchange(info->projs[pn_Load_M], mem); + /* + * a Load immediately after a Store -- a read after write. + * We may remove the Load, if both Load & Store does not have an exception handler + * OR they are in the same block. In the latter case the Load cannot + * throw an exception when the previous Store was quiet. + * + * Why we need to check for Store Exc? If the Store cannot be executed (ROM) + * the exception handler might simply jump into the load block :-( + * We could make it a little bit better if we would know that the exception + * handler of the Store jumps directly to the end... + */ + if ((!pred_info->projs[pn_Store_X_except] && !info->projs[pn_Load_X_except]) || + get_nodes_block(load) == get_nodes_block(pred)) { + DBG_OPT_RAW(load, pred); + exchange( info->projs[pn_Load_res], get_Store_value(pred) ); + + if (info->projs[pn_Load_M]) + exchange(info->projs[pn_Load_M], mem); + + /* no exception */ + if (info->projs[pn_Load_X_except]) + exchange( info->projs[pn_Load_X_except], new_Bad()); + return 1; } - else { - if (info->projs[pn_Load_res]) { - set_Proj_pred(info->projs[pn_Load_res], pred); - set_nodes_block(info->projs[pn_Load_res], get_nodes_block(pred)); - } - if (info->projs[pn_Load_M]) { - /* Actually, this if should not be necessary. Construct the Loads - properly!!! */ - exchange(info->projs[pn_Load_M], mem); - } + } + else if (get_irn_op(pred) == op_Load && get_Load_ptr(pred) == ptr && + get_Load_mode(pred) == load_mode) { + /* + * a Load after a Load -- a read after read. + * We may remove the second Load, if it does not have an exception handler + * OR they are in the same block. In the later case the Load cannot + * throw an exception when the previous Load was quiet. + * + * Here, there is no need to check if the previos Load has an exception hander because + * they would have exact the same exception... + */ + if (! info->projs[pn_Load_X_except] || get_nodes_block(load) == get_nodes_block(pred)) { + ldst_info_t *pred_info = get_irn_link(pred); + + DBG_OPT_RAR(load, pred); + + if (pred_info->projs[pn_Load_res]) { + /* we need a data proj from the previous load for this optimization */ + exchange( info->projs[pn_Load_res], pred_info->projs[pn_Load_res] ); + if (info->projs[pn_Load_M]) + exchange(info->projs[pn_Load_M], mem); + } + else { + if (info->projs[pn_Load_res]) { + set_Proj_pred(info->projs[pn_Load_res], pred); + set_nodes_block(info->projs[pn_Load_res], get_nodes_block(pred)); + } + if (info->projs[pn_Load_M]) { + /* Actually, this if should not be necessary. Construct the Loads + properly!!! */ + exchange(info->projs[pn_Load_M], mem); + } + } + + /* no exception */ + if (info->projs[pn_Load_X_except]) + exchange(info->projs[pn_Load_X_except], new_Bad()); + + return 1; } - - /* no exception */ - if (info->projs[pn_Load_X_except]) - exchange(info->projs[pn_Load_X_except], new_Bad()); - - res = 1; } - } + + /* follow only Load chains */ + if (get_irn_op(pred) != op_Load) + break; + } return res; } @@ -283,7 +504,6 @@ static int optimize_store(ir_node *store) ldst_info_t *info = get_irn_link(store); ir_node *pred, *mem, *ptr, *value, *block; ir_mode *mode; - ldst_info_t *pred_info; int res = 0; if (get_Store_volatility(store) == volatility_is_volatile) @@ -296,40 +516,52 @@ static int optimize_store(ir_node *store) * is possible *(type1 *)p = a; *(type2 *)p = b ... */ - block = get_nodes_block(store); ptr = get_Store_ptr(store); + + /* Check, if the address of this load is used more than once. + * If not, this load cannot be removed in any case. */ + if (get_irn_out_n(ptr) <= 1) + return 0; + + block = get_nodes_block(store); mem = get_Store_mem(store); value = get_Store_value(store); - pred = skip_Proj(mem); mode = get_irn_mode(value); - pred_info = get_irn_link(pred); - - if (get_irn_op(pred) == op_Store && get_Store_ptr(pred) == ptr && - get_nodes_block(pred) == block && get_irn_mode(get_Store_value(pred)) == mode) { - /* - * a store immediately after a store in the same block -- a write after write. - * We may remove the first Store, if it does not have an exception handler. - * - * TODO: What, if both have the same exception handler ??? - */ - if (get_Store_volatility(pred) != volatility_is_volatile && !pred_info->projs[pn_Store_X_except]) { - DBG_OPT_WAW(pred, store); - exchange( pred_info->projs[pn_Store_M], get_Store_mem(pred) ); - res = 1; + /* follow the memory chain as long as there are only Loads */ + for (pred = skip_Proj(mem); ; pred = skip_Proj(get_Load_mem(pred))) { + ldst_info_t *pred_info = get_irn_link(pred); + + if (get_irn_op(pred) == op_Store && get_Store_ptr(pred) == ptr && + get_nodes_block(pred) == block && get_irn_mode(get_Store_value(pred)) == mode) { + /* + * a Store after a Store in the same block -- a write after write. + * We may remove the first Store, if it does not have an exception handler. + * + * TODO: What, if both have the same exception handler ??? + */ + if (get_Store_volatility(pred) != volatility_is_volatile && !pred_info->projs[pn_Store_X_except]) { + DBG_OPT_WAW(pred, store); + exchange( pred_info->projs[pn_Store_M], get_Store_mem(pred) ); + return 1; + } } - } - else if (get_irn_op(pred) == op_Load && get_Load_ptr(pred) == ptr && - value == pred_info->projs[pn_Load_res]) { - /* - * a store a value immediately after a load -- a write after read. - * We may remove the second Store, if it does not have an exception handler. - */ - if (! info->projs[pn_Store_X_except]) { - DBG_OPT_WAR(pred, store); - exchange( info->projs[pn_Store_M], mem ); - res = 1; + else if (get_irn_op(pred) == op_Load && get_Load_ptr(pred) == ptr && + value == pred_info->projs[pn_Load_res]) { + /* + * a Store of a value after a Load -- a write after read. + * We may remove the second Store, if it does not have an exception handler. + */ + if (! info->projs[pn_Store_X_except]) { + DBG_OPT_WAR(store, pred); + exchange( info->projs[pn_Store_M], mem ); + return 1; + } } + + /* follow only Load chains */ + if (get_irn_op(pred) != op_Load) + break; } return res; }