Do not create be_Return for "dead" ends
[libfirm] / ir / be / beabi.c
index 586e38d..a763407 100644 (file)
@@ -96,6 +96,9 @@ struct _be_abi_irg_t {
 
        void                 *cb;           /**< ABI Callback self pointer. */
 
+       pmap                 *keep_map;     /**< mapping blocks to keep nodes. */
+       pset                 *ignore_regs;  /**< Additional registers which shall be ignored. */
+
        arch_irn_handler_t irn_handler;
        arch_irn_ops_t     irn_ops;
        DEBUG_ONLY(firm_dbg_module_t    *dbg;)          /**< The debugging module. */
@@ -108,8 +111,8 @@ struct _be_abi_irg_t {
 static const arch_irn_ops_if_t abi_irn_ops;
 static const arch_irn_handler_t abi_irn_handler;
 
-/* Flag: if set, try to omit the frame pointer if alled by the backend */
-int be_omit_fp = 0;
+/* Flag: if set, try to omit the frame pointer if called by the backend */
+int be_omit_fp = 1;
 
 /*
      _    ____ ___    ____      _ _ _                _
@@ -463,9 +466,13 @@ static ir_node *adjust_call(be_abi_irg_t *env, ir_node *irn, ir_node *curr_sp)
                int curr_ofs      = 0;
                int do_seq        = call->flags.bits.store_args_sequential && !no_alloc;
 
-               /* Reverse list of stack parameters if call arguments are from left to right */
-               if(call->flags.bits.left_to_right) {
-                       for(i = 0; i < n_pos / 2; ++i) {
+               /*
+                * Reverse list of stack parameters if call arguments are from left to right.
+                * We must them reverse again in they are pushed (not stored) and the stack
+                * direction is downwards.
+                */
+               if (call->flags.bits.left_to_right ^ (do_seq && stack_dir < 0)) {
+                       for(i = 0; i < n_pos >> 1; ++i) {
                                int other  = n_pos - i - 1;
                                int tmp    = pos[i];
                                pos[i]     = pos[other];
@@ -493,17 +500,29 @@ static ir_node *adjust_call(be_abi_irg_t *env, ir_node *irn, ir_node *curr_sp)
                        type *param_type       = get_method_param_type(mt, p);
                        int param_size         = get_type_size_bytes(param_type) + arg->space_after;
 
-                       curr_ofs += arg->space_before;
-                       curr_ofs =  round_up2(curr_ofs, arg->alignment);
+                       /*
+                        * If we wanted to build the arguments sequentially,
+                        * the stack pointer for the next must be incremented,
+                        * and the memory value propagated.
+                        */
+                       if (do_seq) {
+                               curr_ofs = 0;
+                               addr = curr_sp = be_new_IncSP(sp, irg, bl, curr_sp, curr_mem,
+                                       param_size + arg->space_before, be_stack_dir_expand);
+                       }
+                       else {
+                               curr_ofs += arg->space_before;
+                               curr_ofs =  round_up2(curr_ofs, arg->alignment);
 
-                       /* Make the expression to compute the argument's offset. */
-                       if(curr_ofs > 0) {
-                               addr = new_r_Const_long(irg, bl, mode_Is, curr_ofs);
-                               addr = new_r_Add(irg, bl, curr_sp, addr, mach_mode);
+                               /* Make the expression to compute the argument's offset. */
+                               if(curr_ofs > 0) {
+                                       addr = new_r_Const_long(irg, bl, mode_Is, curr_ofs);
+                                       addr = new_r_Add(irg, bl, curr_sp, addr, mach_mode);
+                               }
                        }
 
                        /* Insert a store for primitive arguments. */
-                       if(is_atomic_type(param_type)) {
+                       if (is_atomic_type(param_type)) {
                                mem = new_r_Store(irg, bl, curr_mem, addr, param);
                                mem = new_r_Proj(irg, bl, mem, mode_M, pn_Store_M);
                        }
@@ -515,20 +534,12 @@ static ir_node *adjust_call(be_abi_irg_t *env, ir_node *irn, ir_node *curr_sp)
                                mem = new_r_Proj(irg, bl, mem, mode_M, pn_CopyB_M_regular);
                        }
 
-                       obstack_ptr_grow(obst, mem);
-
                        curr_ofs += param_size;
 
-                       /*
-                        * If we wanted to build the arguments sequentially,
-                        * the stack pointer for the next must be incremented,
-                        * and the memory value propagated.
-                        */
-                       if(do_seq) {
-                               curr_ofs = 0;
-                               curr_sp  = be_new_IncSP(sp, irg, bl, curr_sp, no_mem, param_size, be_stack_dir_expand);
+                       if (do_seq)
                                curr_mem = mem;
-                       }
+                       else
+                               obstack_ptr_grow(obst, mem);
                }
 
                in = (ir_node **) obstack_finish(obst);
@@ -612,7 +623,7 @@ static ir_node *adjust_call(be_abi_irg_t *env, ir_node *irn, ir_node *curr_sp)
                be_Call_set_entity(low_call, get_SymConst_entity(call_ptr));
        }
 
-  else
+       else
                low_call = be_new_Call(get_irn_dbg_info(irn), irg, bl, curr_mem, curr_sp, call_ptr,
                                       curr_res_proj + pset_count(caller_save), n_low_args, in,
                                       get_Call_type(irn));
@@ -852,6 +863,7 @@ static void process_calls_in_block(ir_node *bl, void *data)
 
        /* If there were call nodes in the block. */
        if(n > 0) {
+               ir_node *keep;
                ir_node **nodes;
                int i;
 
@@ -879,7 +891,8 @@ static void process_calls_in_block(ir_node *bl, void *data)
 
                /* Keep the last stack state in the block by tying it to Keep node */
                nodes[0] = curr_sp;
-               be_new_Keep(env->isa->sp->reg_class, get_irn_irg(bl), bl, 1, nodes);
+               keep     = be_new_Keep(env->isa->sp->reg_class, get_irn_irg(bl), bl, 1, nodes);
+               pmap_insert(env->keep_map, bl, keep);
        }
 
        set_irn_link(bl, curr_sp);
@@ -1094,6 +1107,9 @@ static reg_node_map_t *reg_map_to_arr(struct obstack *obst, pmap *reg_map)
        return res;
 }
 
+/**
+ * Creates a barrier.
+ */
 static ir_node *create_barrier(be_abi_irg_t *env, ir_node *bl, ir_node **mem, pmap *regs, int in_req)
 {
        ir_graph *irg = env->birg->irg;
@@ -1129,7 +1145,9 @@ static ir_node *create_barrier(be_abi_irg_t *env, ir_node *bl, ir_node **mem, pm
                be_set_constr_single_reg(irn, pos, reg);
                be_node_set_reg_class(irn, pos, reg->reg_class);
                arch_set_irn_register(env->birg->main_env->arch_env, proj, reg);
-               if(arch_register_type_is(reg, ignore))
+
+               /* if the proj projects a ignore register or a node which is set to ignore, propagate this property. */
+               if(arch_register_type_is(reg, ignore) || arch_irn_is(env->birg->main_env->arch_env, in[n], ignore))
                        be_node_set_flags(irn, pos, arch_irn_flags_ignore);
 
                pmap_insert(regs, (void *) reg, proj);
@@ -1143,6 +1161,113 @@ static ir_node *create_barrier(be_abi_irg_t *env, ir_node *bl, ir_node **mem, pm
        return irn;
 }
 
+/**
+ * Creates a be_Return for a Return node.
+ *
+ * @param @env    the abi environment
+ * @param irn     the Return node or NULL if there was none
+ * @param bl      the block where the be_Retun should be placed
+ * @param mem     the current memory
+ * @param n_res   number of return results
+ */
+static ir_node *create_be_return(be_abi_irg_t *env, ir_node *irn, ir_node *bl, ir_node *mem, int n_res) {
+       be_abi_call_t *call = env->call;
+       const arch_isa_t *isa = env->birg->main_env->arch_env->isa;
+
+       pmap *reg_map  = pmap_create();
+       ir_node *keep  = pmap_get(env->keep_map, bl);
+       int in_max;
+       ir_node *ret;
+       int i, n;
+       ir_node **in;
+       ir_node *stack;
+       const arch_register_t **regs;
+       pmap_entry *ent ;
+
+       /*
+               get the valid stack node in this block.
+               If we had a call in that block there is a Keep constructed by process_calls()
+               which points to the last stack modification in that block. we'll use
+               it then. Else we use the stack from the start block and let
+               the ssa construction fix the usage.
+       */
+       stack = be_abi_reg_map_get(env->regs, isa->sp);
+       if (keep) {
+               stack = get_irn_n(keep, 0);
+               exchange(keep, new_r_Bad(env->birg->irg));
+       }
+       be_abi_reg_map_set(reg_map, isa->sp, stack);
+
+       /* Insert results for Return into the register map. */
+       for(i = 0; i < n_res; ++i) {
+               ir_node *res           = get_Return_res(irn, i);
+               be_abi_call_arg_t *arg = get_call_arg(call, 1, i);
+               assert(arg->in_reg && "return value must be passed in register");
+               pmap_insert(reg_map, (void *) arg->reg, res);
+       }
+
+       /* Add uses of the callee save registers. */
+       pmap_foreach(env->regs, ent) {
+               const arch_register_t *reg = ent->key;
+               if(arch_register_type_is(reg, callee_save) || arch_register_type_is(reg, ignore))
+                       pmap_insert(reg_map, ent->key, ent->value);
+       }
+
+       /* Make the Epilogue node and call the arch's epilogue maker. */
+       create_barrier(env, bl, &mem, reg_map, 1);
+       call->cb->epilogue(env->cb, bl, &mem, reg_map);
+
+       /*
+               Maximum size of the in array for Return nodes is
+               return args + callee save/ignore registers + memory + stack pointer
+       */
+       in_max = pmap_count(reg_map) + n_res + 2;
+
+       in   = obstack_alloc(&env->obst, in_max * sizeof(in[0]));
+       regs = obstack_alloc(&env->obst, in_max * sizeof(regs[0]));
+
+       in[0]   = mem;
+       in[1]   = be_abi_reg_map_get(reg_map, isa->sp);
+       regs[0] = NULL;
+       regs[1] = isa->sp;
+       n       = 2;
+
+       /* clear SP entry, since it has already been grown. */
+       pmap_insert(reg_map, (void *) isa->sp, NULL);
+       for(i = 0; i < n_res; ++i) {
+               ir_node *res           = get_Return_res(irn, i);
+               be_abi_call_arg_t *arg = get_call_arg(call, 1, i);
+
+               in[n]     = be_abi_reg_map_get(reg_map, arg->reg);
+               regs[n++] = arg->reg;
+
+               /* Clear the map entry to mark the register as processed. */
+               be_abi_reg_map_set(reg_map, arg->reg, NULL);
+       }
+
+       /* grow the rest of the stuff. */
+       pmap_foreach(reg_map, ent) {
+               if(ent->value) {
+                       in[n]     = ent->value;
+                       regs[n++] = ent->key;
+               }
+       }
+
+       /* The in array for the new back end return is now ready. */
+       ret = be_new_Return(irn ? get_irn_dbg_info(irn) : NULL, env->birg->irg, bl, n_res, n, in);
+
+       /* Set the register classes of the return's parameter accordingly. */
+       for(i = 0; i < n; ++i)
+               if(regs[i])
+                       be_node_set_reg_class(ret, i, regs[i]->reg_class);
+
+       /* Free the space of the Epilog's in array and the register <-> proj map. */
+       obstack_free(&env->obst, in);
+       pmap_destroy(reg_map);
+
+       return ret;
+}
+
 /**
  * Modify the irg itself and the frame type.
  */
@@ -1173,7 +1298,6 @@ static void modify_irg(be_abi_irg_t *env)
        const ir_edge_t *edge;
        ir_type *arg_type, *bet_type;
 
-       pmap_entry *ent;
        bitset_t *used_proj_nr;
        DEBUG_ONLY(firm_dbg_module_t *dbg = env->dbg;)
 
@@ -1275,17 +1399,21 @@ static void modify_irg(be_abi_irg_t *env)
 
        /* Generate the Prologue */
        fp_reg  = call->cb->prologue(env->cb, &mem, env->regs);
+
+       /* do the stack allocation BEFORE the barrier, or spill code
+          might be added before it */
+       env->init_sp  = be_abi_reg_map_get(env->regs, sp);
+       env->init_sp = be_new_IncSP(sp, irg, bl, env->init_sp, no_mem, BE_STACK_FRAME_SIZE, be_stack_dir_expand);
+       be_abi_reg_map_set(env->regs, sp, env->init_sp);
+
        barrier = create_barrier(env, bl, &mem, env->regs, 0);
 
        env->init_sp  = be_abi_reg_map_get(env->regs, sp);
-       env->init_sp  = be_new_IncSP(sp, irg, bl, env->init_sp, no_mem, BE_STACK_FRAME_SIZE, be_stack_dir_expand);
        arch_set_irn_register(env->birg->main_env->arch_env, env->init_sp, sp);
-       be_abi_reg_map_set(env->regs, sp, env->init_sp);
+
        frame_pointer = be_abi_reg_map_get(env->regs, fp_reg);
        set_irg_frame(irg, frame_pointer);
-
-       assert(is_Proj(frame_pointer));
-       be_node_set_flags(barrier, BE_OUT_POS(get_Proj_proj(frame_pointer)), arch_irn_flags_ignore);
+       pset_insert_ptr(env->ignore_regs, fp_reg);
 
        /* Now, introduce stack param nodes for all parameters passed on the stack */
        for(i = 0; i < max_arg; ++i) {
@@ -1327,91 +1455,16 @@ static void modify_irg(be_abi_irg_t *env)
        }
 
        /* All Return nodes hang on the End node, so look for them there. */
-       for(i = 0, n = get_irn_arity(end); i < n; ++i) {
-               ir_node *irn = get_irn_n(end, i);
-
-               if(get_irn_opcode(irn) == iro_Return) {
-                       ir_node *bl    = get_nodes_block(irn);
-                       int n_res      = get_Return_n_ress(irn);
-                       pmap *reg_map  = pmap_create();
-                       ir_node *mem   = get_Return_mem(irn);
-                       int in_max;
-                       ir_node *ret;
-                       int i, n;
-                       ir_node **in;
-                       const arch_register_t **regs;
-
-                       pmap_insert(reg_map, (void *) sp, pmap_get(env->regs, (void *) sp));
-
-                       /* Insert results for Return into the register map. */
-                       for(i = 0; i < n_res; ++i) {
-                               ir_node *res           = get_Return_res(irn, i);
-                               be_abi_call_arg_t *arg = get_call_arg(call, 1, i);
-                               assert(arg->in_reg && "return value must be passed in register");
-                               pmap_insert(reg_map, (void *) arg->reg, res);
-                       }
-
-                       /* Add uses of the callee save registers. */
-                       pmap_foreach(env->regs, ent) {
-                               const arch_register_t *reg = ent->key;
-                               if(arch_register_type_is(reg, callee_save) || arch_register_type_is(reg, ignore))
-                                       pmap_insert(reg_map, ent->key, ent->value);
-                       }
-
-                       /* Make the Epilogue node and call the arch's epilogue maker. */
-                       create_barrier(env, bl, &mem, reg_map, 1);
-                       call->cb->epilogue(env->cb, bl, &mem, reg_map);
-
-                       /*
-                               Maximum size of the in array for Return nodes is
-                               return args + callee save/ignore registers + memory + stack pointer
-                       */
-                       in_max = pmap_count(reg_map) + get_Return_n_ress(irn) + 2;
-
-                       in   = obstack_alloc(&env->obst, in_max * sizeof(in[0]));
-                       regs = obstack_alloc(&env->obst, in_max * sizeof(regs[0]));
-
-                       in[0]   = mem;
-                       in[1]   = be_abi_reg_map_get(reg_map, sp);
-                       regs[0] = NULL;
-                       regs[1] = sp;
-                       n       = 2;
-
-                       /* clear SP entry, since it has already been grown. */
-                       pmap_insert(reg_map, (void *) sp, NULL);
-                       for(i = 0; i < n_res; ++i) {
-                               ir_node *res           = get_Return_res(irn, i);
-                               be_abi_call_arg_t *arg = get_call_arg(call, 1, i);
-
-                               in[n]     = be_abi_reg_map_get(reg_map, arg->reg);
-                               regs[n++] = arg->reg;
-
-                               /* Clear the map entry to mark the register as processed. */
-                               be_abi_reg_map_set(reg_map, arg->reg, NULL);
-                       }
-
-                       /* grow the rest of the stuff. */
-                       pmap_foreach(reg_map, ent) {
-                               if(ent->value) {
-                                       in[n]     = ent->value;
-                                       regs[n++] = ent->key;
-                               }
-                       }
+       for (i = 0, n = get_Block_n_cfgpreds(end); i < n; ++i) {
+               ir_node *irn = get_Block_cfgpred(end, i);
 
-                       /* The in array for the new back end return is now ready. */
-                       ret = be_new_Return(get_irn_dbg_info(irn), irg, bl, n, in);
-
-                       /* Set the register classes of the return's parameter accordingly. */
-                       for(i = 0; i < n; ++i)
-                               if(regs[i])
-                                       be_node_set_reg_class(ret, i, regs[i]->reg_class);
-
-                       /* Free the space of the Epilog's in array and the register <-> proj map. */
-                       obstack_free(&env->obst, in);
+               if (is_Return(irn)) {
+                       ir_node *ret = create_be_return(env, irn, get_nodes_block(irn), get_Return_mem(irn), get_Return_n_ress(irn));
                        exchange(irn, ret);
-                       pmap_destroy(reg_map);
                }
        }
+       /* if we have endless loops here, n might be <= 0. Do NOT create a be_Return than,
+          the code is dead and will never be executed. */
 
        del_pset(dont_save);
        obstack_free(&env->obst, args);
@@ -1436,11 +1489,15 @@ be_abi_irg_t *be_abi_introduce(be_irg_t *birg)
        pmap_entry *ent;
        ir_node *dummy;
 
+       obstack_init(&env->obst);
+
        env->isa           = birg->main_env->arch_env->isa;
        env->method_type   = get_entity_type(get_irg_entity(irg));
        env->call          = be_abi_call_new();
        arch_isa_get_call_abi(env->isa, env->method_type, env->call);
 
+       env->ignore_regs      = pset_new_ptr_default();
+       env->keep_map         = pmap_create();
        env->dce_survivor     = new_survive_dce();
        env->birg             = birg;
        env->stack_phis       = pset_new_ptr(16);
@@ -1449,8 +1506,6 @@ be_abi_irg_t *be_abi_introduce(be_irg_t *birg)
 
        env->cb = env->call->cb->init(env->call, birg->main_env->arch_env, irg);
 
-       obstack_init(&env->obst);
-
        memcpy(&env->irn_handler, &abi_irn_handler, sizeof(abi_irn_handler));
        env->irn_ops.impl = &abi_irn_ops;
 
@@ -1460,6 +1515,9 @@ be_abi_irg_t *be_abi_introduce(be_irg_t *birg)
        /* Process the IRG */
        modify_irg(env);
 
+       /* We don't need the keep map anymore. */
+       pmap_destroy(env->keep_map);
+
        /* reroute the stack origin of the calls to the true stack origin. */
        edges_reroute(dummy, env->init_sp, irg);
        edges_reroute(old_frame, get_irg_frame(irg), irg);
@@ -1480,12 +1538,22 @@ void be_abi_free(be_abi_irg_t *env)
 {
        free_survive_dce(env->dce_survivor);
        del_pset(env->stack_phis);
+       del_pset(env->ignore_regs);
        pmap_destroy(env->regs);
        obstack_free(&env->obst, NULL);
        arch_env_pop_irn_handler(env->birg->main_env->arch_env);
        free(env);
 }
 
+void be_abi_put_ignore_regs(be_abi_irg_t *abi, const arch_register_class_t *cls, bitset_t *bs)
+{
+       arch_register_t *reg;
+
+       for(reg = pset_first(abi->ignore_regs); reg; reg = pset_next(abi->ignore_regs))
+               if(reg->reg_class == cls)
+                       bitset_set(bs, reg->index);
+}
+
 
 /*