nsz Git - libfirm/blob - ir/be/mips/mips_scheduler.c

   1 /* Mips implementation of list scheduler selector */
   2 /* $Id$ */
   3
   4 #ifdef HAVE_CONFIG_H
   5 #include "config.h"
   6 #endif
   7
   8 #ifdef HAVE_STDLIB_H
   9 #include <stdlib.h>
  10 #endif
  11
  12 #include "mips_scheduler.h"
  13
  14 #include "../besched_t.h"
  15 #include "../be.h"
  16 #include "../beabi.h"
  17 #include "iredges.h"
  18 #include "ircons.h"
  19 #include "gen_mips_regalloc_if.h"
  20
  21 #include "mips_new_nodes.h"
  22
  23 list_sched_selector_t mips_sched_selector;
  24
  25 typedef struct {
  26         const arch_env_t* arch_env;
  27         pset *div_set;
  28         /**
  29          * This array holds an entry for each register that specifies how much cycles
  30          * have to pass before we can access that register again
  31          * (because mips will write the register value back in the WB phase of the pipeline)
  32          */
  33         int busy_registers[N_mips_gp_REGS];
  34         /// current block
  35         ir_node* block;
  36         ir_node* last_nop;
  37 } mips_sched_env_t;
  38
  39 static void *mips_scheduler_init_graph(const list_sched_selector_t *vtab, const arch_env_t *arch_env, ir_graph *irg)
  40 {
  41         mips_sched_env_t *sched_env = xmalloc(sizeof(sched_env[0]));
  42         memset(sched_env, 0, sizeof(sched_env[0]));
  43
  44         sched_env->arch_env = arch_env;
  45         sched_env->div_set = new_pset(pset_default_ptr_cmp, 4);
  46
  47         return sched_env;
  48 }
  49
  50 static void mips_scheduler_finish_graph(void* graph_env)
  51 {
  52         mips_sched_env_t *sched_env = (mips_sched_env_t*) graph_env;
  53         del_pset(sched_env->div_set);
  54 }
  55
  56 static void *mips_scheduler_init_block(void *graph_env, ir_node *block)
  57 {
  58         mips_sched_env_t *sched_env = (mips_sched_env_t*) graph_env;
  59         assert(pset_count(sched_env->div_set) == 0);
  60         srand(12234);
  61         // TODO later we might have blocks that don't end in a jump
  62         memset(&sched_env->busy_registers, 0, sizeof(sched_env->busy_registers));
  63         sched_env->block = block;
  64         sched_env->last_nop = NULL;
  65         return sched_env;
  66 }
  67
  68 static void mips_scheduler_finish_block(void* graph_env)
  69 {
  70         mips_sched_env_t *sched_env = (mips_sched_env_t*) graph_env;
  71         // attach last nop to end node (so that firm doesn't discard it)
  72         if(sched_env->last_nop != NULL) {
  73                 ir_node* end = get_irg_end(get_irn_irg(sched_env->block));
  74                 (void) end;
  75                 // TODO
  76         }
  77         sched_env->block = NULL;
  78 }
  79
  80 static int mips_scheduler_to_appear_in_schedule(void *block_env, const ir_node *irn)
  81 {
  82         return is_mips_irn(irn) && !is_mips_zero(irn) && !is_mips_reinterpret_conv(irn) && !is_mips_fallthrough(irn);
  83 }
  84
  85 static void mips_collect_mflohis(pset* set, ir_node* node) {
  86         // construct a list of nodes that need to be scheduled before
  87         // we are allowed to schedule another div or mul instruction
  88         const ir_edge_t *edge, *edge2;
  89
  90         if(is_mips_div(node)) {
  91                 foreach_out_edge(node, edge) {
  92                         const ir_node* node2 = get_edge_src_irn(edge);
  93
  94                         assert(is_Proj(node2));
  95                         foreach_out_edge(node2, edge2) {
  96                                 const ir_node* node3 = get_edge_src_irn(edge2);
  97                                 if(is_mips_mfhi(node3) || is_mips_mflo(node3))
  98                                         pset_insert_ptr(set, node3);
  99                         }
 100                 }
 101         } else if(is_mips_mult(node)) {
 102                 foreach_out_edge(node, edge) {
 103                         const ir_node* node2 = get_edge_src_irn(edge);
 104
 105                         if(is_mips_mfhi(node2) || is_mips_mflo(node2))
 106                                 pset_insert_ptr(set, node2);
 107                 }
 108         }
 109 }
 110
 111 static int mips_scheduler_node_allowed(mips_sched_env_t *sched_env, ir_node* node)
 112 {
 113         if(pset_count(sched_env->div_set) != 0 && (is_mips_div(node) || is_mips_mult(node))) {
 114                 return 0;
 115         }
 116
 117         return 1;
 118 }
 119
 120 static ir_node *mips_scheduler_select(void *block_env, nodeset *ready_set)
 121 {
 122         mips_sched_env_t *sched_env = (mips_sched_env_t*) block_env;
 123         const arch_env_t *arch_env = (const arch_env_t*) sched_env->arch_env;
 124         ir_node *node = NULL;
 125         ir_node *block = sched_env->block;
 126         ir_node *condjmp = NULL;
 127         ir_graph *irg = get_irn_irg(block);
 128         int have_non_branch_nodes = 0;
 129
 130         // test all nodes in the ready set and take the first non-branch that
 131         // is allowed
 132         for (node = nodeset_first(ready_set); node != NULL; node = nodeset_next(ready_set)) {
 133                 if (arch_irn_class_is(arch_env, node, branch)) {
 134                         if (is_irn_forking(node))
 135                                 condjmp = node;
 136                         continue;
 137                 }
 138
 139                 have_non_branch_nodes = 1;
 140
 141                 if (mips_scheduler_node_allowed(sched_env, node))
 142                 {
 143                         nodeset_break(ready_set);
 144
 145                         // TODO update busy_registers
 146
 147                         if (is_mips_div(node) || is_mips_mult(node)) {
 148                                 mips_collect_mflohis(sched_env->div_set, node);
 149                         } else if(is_mips_mflo(node) || is_mips_mfhi(node)) {
 150                                 pset_remove_ptr(sched_env->div_set, node);
 151                         }
 152
 153                         return node;
 154                 }
 155         }
 156
 157         // if we arrive here no non-branch node was found that we can emit
 158
 159         // return a branch if there are just branches left
 160         if(!have_non_branch_nodes) {
 161                 // schedule conditional branches before non-conditional ones
 162                 if(condjmp != NULL) {
 163                         return condjmp;
 164                 }
 165                 node = nodeset_first(ready_set);
 166                 assert(arch_irn_class_is(arch_env, node, branch));
 167                 nodeset_break(ready_set);
 168                 return node;
 169         }
 170
 171         // emit a nop
 172         node = new_rd_mips_nop(NULL, irg, block, mode_M);
 173         keep_alive(node);
 174         return node;
 175 }
 176
 177 /**
 178  * Returns the reg_pressure scheduler with to_appear_in_schedule() overloaded
 179  */
 180 const list_sched_selector_t *mips_get_list_sched_selector(const void *self)
 181 {
 182         memset(&mips_sched_selector, 0, sizeof(mips_sched_selector));
 183         mips_sched_selector.init_graph = mips_scheduler_init_graph;
 184         mips_sched_selector.init_block = mips_scheduler_init_block;
 185         mips_sched_selector.select = mips_scheduler_select;
 186         mips_sched_selector.to_appear_in_schedule = mips_scheduler_to_appear_in_schedule;
 187         mips_sched_selector.finish_block = mips_scheduler_finish_block;
 188         mips_sched_selector.finish_graph = mips_scheduler_finish_graph;
 189         return &mips_sched_selector;
 190 }