X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fbe%2Fbechordal.c;h=e7950b64614c099323bc254ad4354d0d1f294616;hb=ba873a5483697d4ff93e3980d7b6a1b5cbc491b5;hp=0c4334c584b764f60c089f6e0c8214d7e41c39dc;hpb=33be8f50c457cd2e6e8a4fc488248d0d47c7f491;p=libfirm diff --git a/ir/be/bechordal.c b/ir/be/bechordal.c index 0c4334c58..e7950b646 100644 --- a/ir/be/bechordal.c +++ b/ir/be/bechordal.c @@ -58,6 +58,7 @@ typedef struct _be_chordal_alloc_env_t { be_chordal_env_t *chordal_env; + pset *pre_colored; /**< Set of precolored nodes. */ bitset_t *live; /**< A liveness bitset. */ bitset_t *colors; /**< The color mask. */ bitset_t *in_colors; /**< Colors used by live in values. */ @@ -161,90 +162,186 @@ static INLINE int has_reg_class(const be_chordal_env_t *env, const ir_node *irn) return arch_irn_has_reg_class(env->main_env->arch_env, irn, -1, env->cls); } -static border_t *handle_constraint_perm(be_chordal_alloc_env_t *alloc_env, border_t *perm_border) -{ - const arch_env_t *arch_env = alloc_env->chordal_env->main_env->arch_env; - bitset_t *bs = bitset_alloca(alloc_env->chordal_env->cls->n_regs); - ir_node *perm = perm_border->irn; - int n = get_irn_arity(perm_border->irn); - int n_projs = 0; +#define has_limited_constr(req, irn) \ + (arch_get_register_req(arch_env, (req), irn, -1) && (req)->type == arch_register_req_type_limited) - border_t *b, *next_border, *cnstr_border; +/** + * Handle register targeting constraints signaled by a Perm. + * @param alloc_env Private data for the allocation phase. + * @param perm The Perm node guarding the constrained node. + * @return The constrained node. + + Pro-coloring works as follows: + + +-----------------------------------+ + | Perm | + +---.-------.--------.---------.----+ + | | | | + +---+--+ | | | + | Proj | | | | + +------+ | | | + | | | + +--+---+ | | + | Proj | | | + +--.---+ | | + | | | + | +--+---+ | + | | Proj | | + | +------+ | + | | + | +---+--+ + `-. | Proj | Result: + `._ +---.--+ R1 + `. | + `-. | + `._ | + +`.-+--+ + |Constr| Result: + +------+ R2 + + 1) Look at all Projs of the Perm if they have output constraints. + If one has an output constraint, pre-color it, else record it + in the set leftover. Its color has to be chosen after all + constrained nodes are colored. Furthermore record all colors + used in the pre-coloring in the set colors_used. + + 2) Look whether the first node not a Proj (this is the constrained + node due to which the Perm has been inserted) has an output + constraint. If yes, pre-color the node accordingly else do nothing + since the node's input constraints are modelled by the Proj's + output constraint. + + There's one subtle point here: If thenode has an output constraint + and the live range of some Proj ends at that node, we must give + that Proj the color of the constrained node. Otherwise the + available colors may not suffice for the rest of the projs. + + 3) At last, color the Projs which have not been colored yet with the + left over colors. + + So afterwards, everything including the constrained node will + be colored and the assign() phase can complete this coloring. + Note that therefore, we put the pre-colored nodes in a set + called pre_colored(). - arch_register_req_t req; - ir_node *cnstr; + */ +static ir_node *handle_constraints_at_perm(be_chordal_alloc_env_t *alloc_env, ir_node *perm) +{ + be_chordal_env_t *env = alloc_env->chordal_env; + firm_dbg_module_t *dbg = env->dbg; + const arch_env_t *arch_env = env->main_env->arch_env; + + pset *leftover = pset_new_ptr(8); + bitset_t *bs = bitset_alloca(env->cls->n_regs); + bitset_t *colors_used = bitset_alloca(env->cls->n_regs); + ir_node *irn, *cnstr; int has_cnstr = 0; - int i, m; + int col; + arch_register_req_t req; + const arch_register_t *reg, *cnstr_reg = NULL; - assert(is_Perm(perm)); + assert(be_is_Perm(perm)); + + DBG((dbg, LEVEL_2, "Constraints on %+F\n", perm)); /* - * After the Perm, there must be a sequence of Projs - * which extract the permuted values of the Perm. + * Color constrained Projs first. */ - for(b = perm_border; is_Proj(b->irn); b = border_next(b)) { - assert(is_Proj(b->irn)); - assert(b->is_def); - n_projs++; - } + for(irn = sched_next(perm); is_Proj(irn); irn = sched_next(irn)) { + arch_register_req_t req; - cnstr_border = b; - next_border = border_next(b); - cnstr = b->irn; + if(has_limited_constr(&req, irn)) { + bitset_clear_all(bs); + req.data.limited(irn, -1, bs); + col = bitset_next_set(bs, 0); + reg = arch_register_for_index(env->cls, col); - assert(n_projs == n && "There must be as many Projs as the Perm is wide"); + pset_insert_ptr(alloc_env->pre_colored, irn); + arch_set_irn_register(arch_env, irn, reg); + bitset_set(colors_used, col); - /* The node after the last perm proj must be the constrained node. */ - cnstr = b->irn; - for(i = -1, m = get_irn_arity(cnstr); i < m; ++i) { - req.type = arch_register_req_type_normal; - if(arch_get_register_req(arch_env, &req, cnstr, i) && req.type == arch_register_req_type_limited) { - has_cnstr = 1; - break; + DBG((dbg, LEVEL_2, "\tPerm Proj with constraints: %+F set to %s\n", irn, reg->name)); } + + else + pset_insert_ptr(leftover, irn); + } + cnstr = irn; - assert(has_cnstr && "The node must have a register constraint"); + if(has_limited_constr(&req, cnstr)) { + bitset_clear_all(bs); + req.data.limited(cnstr, -1, bs); + col = bitset_next_set(colors_used, 0); + reg = arch_register_for_index(env->cls, col); - /* - * Consider the code in beconstrperm.c - * We turned each input constraint of a node into an output - * constraint of the Perm's Proj. So we only have to - * consider output constraints here. - */ - for(b = perm_border; b != next_border; b = border_next(b)) { - ir_node *irn = b->irn; + arch_set_irn_register(arch_env, cnstr, reg); + pset_insert_ptr(alloc_env->pre_colored, cnstr); - req.type = arch_register_req_type_normal; - if(arch_get_register_req(arch_env, &req, irn, -1) && req.type == arch_register_req_type_limited) { - const arch_register_t *reg; - int col; + DBG((dbg, LEVEL_2, "\tConstrained node: %+F set to %s\n", irn, reg->name)); - bitset_clear_all(bs); - req.data.limited(irn, -1, bs); - col = bitset_next_set(bs, 0); - reg = arch_register_for_index(alloc_env->chordal_env->cls, col); + /* + * The color of the constrained node must not be used! + * The Proj which has been assigned that color might + * interfere with the constrained node which leads + * to an invalid register allocation. + */ + assert(!bitset_is_set(colors_used, reg->index)); - arch_set_irn_register(arch_env, irn, reg); - bitset_set(alloc_env->colors, col); + /* + * Look for a Proj not interfering with the constrained node. + * This Proj can be safely set to the constrafined nodes + * color. + */ + for(irn = pset_first(leftover); irn; irn = pset_next(leftover)) { + if(!values_interfere(irn, cnstr)) { + + DBG((dbg, LEVEL_2, "\tFound Proj not interfering with contr node %+F set to %s\n", irn, reg->name)); + pset_insert_ptr(alloc_env->pre_colored, irn); + arch_set_irn_register(arch_env, irn, reg); + bitset_set(colors_used, reg->index); + pset_remove_ptr(leftover, irn); + pset_break(leftover); + break; + } } } - for(b = perm_border; b != next_border; b = border_next(b)) { - ir_node *irn = b->irn; - int nr = get_irn_graph_nr(irn); - - bitset_set(alloc_env->live, nr); + /* + * Color the leftover Projs with the leftover colors. + */ + for(irn = pset_first(leftover); irn; irn = pset_next(leftover)) { + col = bitset_next_clear(colors_used, 0); + reg = arch_register_for_index(env->cls, col); - if(arch_get_irn_register(arch_env, irn) == NULL) { - int col = bitset_next_clear(alloc_env->colors, 0); - const arch_register_t *reg = arch_register_for_index(alloc_env->chordal_env->cls, col); + arch_set_irn_register(arch_env, irn, reg); + pset_insert_ptr(alloc_env->pre_colored, irn); + bitset_set(colors_used, col); - arch_set_irn_register(arch_env, irn, reg); - } + DBG((dbg, LEVEL_2, "\tLeft over %+F set to %s\n", irn, reg->name)); } - return cnstr_border; + del_pset(leftover); + return cnstr; +} + +/** + * Handle constraint nodes in each basic block. + * be_insert_constr_perms() inserts Perm nodes which perm + * over all values live at the constrained node right in front + * of the constrained node. These Perms signal a constrained node. + * For further comments, refer to handle_constraints_at_perm(). + */ +static void constraints(ir_node *bl, void *data) +{ + be_chordal_alloc_env_t *env = data; + arch_env_t *arch_env = env->chordal_env->main_env->arch_env; + ir_node *irn; + + for(irn = sched_first(bl); !sched_is_end(irn); irn = sched_next(irn)) { + if(be_is_Perm(irn)) + irn = handle_constraints_at_perm(env, irn); + } } /** @@ -425,18 +522,26 @@ static void assign(ir_node *block, void *env_ptr) DBG((dbg, LEVEL_4, "\tcolors in use: %b\n", colors)); - col = bitset_next_clear(colors, 0); - reg = arch_register_for_index(env->cls, col); + if(pset_find_ptr(alloc_env->pre_colored, irn)) { + reg = arch_get_irn_register(arch_env, irn); + col = reg->index; + assert(!bitset_is_set(colors, col) && "pre-colored register must be free"); + } - assert(arch_get_irn_register(arch_env, irn) == NULL && "This node must not have been assigned a register yet"); - assert(!bitset_is_set(live, nr) && "Value's definition must not have been encountered"); + else { + col = bitset_next_clear(colors, 0); + reg = arch_register_for_index(env->cls, col); + assert(arch_get_irn_register(arch_env, irn) == NULL && "This node must not have been assigned a register yet"); + } bitset_set(colors, col); - bitset_set(live, nr); - arch_set_irn_register(arch_env, irn, reg); + DBG((dbg, LEVEL_1, "\tassigning register %s(%d) to %+F\n", arch_register_get_name(reg), col, irn)); + + assert(!bitset_is_set(live, nr) && "Value's definition must not have been encountered"); + bitset_set(live, nr); } /* Clear the color upon a use. */ @@ -451,18 +556,6 @@ static void assign(ir_node *block, void *env_ptr) bitset_clear(colors, col); bitset_clear(live, nr); - - /* - * If we encounter a Perm, it is due to register constraints. - * To achieve a valid coloring in the presence of register - * constraints, we invoke a special function which takes care - * that all constraints are fulfilled. - * This function assigned valid colors to the projs of the - * Perm and the constrained node itself and skips these - * nodes in the border list. - */ - if(is_Perm(b->irn)) - b = handle_constraint_perm(alloc_env, border_next(b)); } } @@ -485,6 +578,10 @@ void be_ra_chordal_color(be_chordal_env_t *chordal_env) env.colors = bitset_malloc(colors_n); env.in_colors = bitset_malloc(colors_n); env.colors_n = colors_n; + env.pre_colored = pset_new_ptr_default(); + + /* Handle register targeting constraints */ + dom_tree_walk_irg(irg, constraints, NULL, &env); /* First, determine the pressure */ dom_tree_walk_irg(irg, pressure, NULL, &env); @@ -508,4 +605,6 @@ void be_ra_chordal_color(be_chordal_env_t *chordal_env) free(env.live); free(env.colors); free(env.in_colors); + + del_pset(env.pre_colored); }