/* Miscellaneous SSA utility functions. Copyright (C) 2001-2014 Free Software Foundation, Inc. This file is part of GCC. GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. GCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GCC; see the file COPYING3. If not see . */ #include "config.h" #include "system.h" #include "coretypes.h" #include "tm.h" #include "tree.h" #include "stor-layout.h" #include "flags.h" #include "tm_p.h" #include "target.h" #include "langhooks.h" #include "basic-block.h" #include "function.h" #include "gimple-pretty-print.h" #include "pointer-set.h" #include "tree-ssa-alias.h" #include "internal-fn.h" #include "gimple-fold.h" #include "gimple-expr.h" #include "is-a.h" #include "gimple.h" #include "gimplify.h" #include "gimple-iterator.h" #include "gimple-walk.h" #include "gimple-ssa.h" #include "tree-phinodes.h" #include "ssa-iterators.h" #include "stringpool.h" #include "tree-ssanames.h" #include "tree-ssa-loop-manip.h" #include "tree-into-ssa.h" #include "tree-ssa.h" #include "tree-inline.h" #include "hashtab.h" #include "tree-pass.h" #include "diagnostic-core.h" #include "cfgloop.h" #include "cfgexpand.h" /* Pointer map of variable mappings, keyed by edge. */ static struct pointer_map_t *edge_var_maps; /* Add a mapping with PHI RESULT and PHI DEF associated with edge E. */ void redirect_edge_var_map_add (edge e, tree result, tree def, source_location locus) { void **slot; edge_var_map_vector *head; edge_var_map new_node; if (edge_var_maps == NULL) edge_var_maps = pointer_map_create (); slot = pointer_map_insert (edge_var_maps, e); head = (edge_var_map_vector *) *slot; if (!head) vec_safe_reserve (head, 5); new_node.def = def; new_node.result = result; new_node.locus = locus; vec_safe_push (head, new_node); *slot = head; } /* Clear the var mappings in edge E. */ void redirect_edge_var_map_clear (edge e) { void **slot; edge_var_map_vector *head; if (!edge_var_maps) return; slot = pointer_map_contains (edge_var_maps, e); if (slot) { head = (edge_var_map_vector *) *slot; vec_free (head); *slot = NULL; } } /* Duplicate the redirected var mappings in OLDE in NEWE. Since we can't remove a mapping, let's just duplicate it. This assumes a pointer_map can have multiple edges mapping to the same var_map (many to one mapping), since we don't remove the previous mappings. */ void redirect_edge_var_map_dup (edge newe, edge olde) { void **new_slot, **old_slot; edge_var_map_vector *head; if (!edge_var_maps) return; new_slot = pointer_map_insert (edge_var_maps, newe); old_slot = pointer_map_contains (edge_var_maps, olde); if (!old_slot) return; head = (edge_var_map_vector *) *old_slot; edge_var_map_vector *new_head = NULL; if (head) new_head = vec_safe_copy (head); else vec_safe_reserve (new_head, 5); *new_slot = new_head; } /* Return the variable mappings for a given edge. If there is none, return NULL. */ edge_var_map_vector * redirect_edge_var_map_vector (edge e) { void **slot; /* Hey, what kind of idiot would... you'd be surprised. */ if (!edge_var_maps) return NULL; slot = pointer_map_contains (edge_var_maps, e); if (!slot) return NULL; return (edge_var_map_vector *) *slot; } /* Used by redirect_edge_var_map_destroy to free all memory. */ static bool free_var_map_entry (const void *key ATTRIBUTE_UNUSED, void **value, void *data ATTRIBUTE_UNUSED) { edge_var_map_vector *head = (edge_var_map_vector *) *value; vec_free (head); return true; } /* Clear the edge variable mappings. */ void redirect_edge_var_map_destroy (void) { if (edge_var_maps) { pointer_map_traverse (edge_var_maps, free_var_map_entry, NULL); pointer_map_destroy (edge_var_maps); edge_var_maps = NULL; } } /* Remove the corresponding arguments from the PHI nodes in E's destination block and redirect it to DEST. Return redirected edge. The list of removed arguments is stored in a vector accessed through edge_var_maps. */ edge ssa_redirect_edge (edge e, basic_block dest) { gimple_stmt_iterator gsi; gimple phi; redirect_edge_var_map_clear (e); /* Remove the appropriate PHI arguments in E's destination block. */ for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); gsi_next (&gsi)) { tree def; source_location locus ; phi = gsi_stmt (gsi); def = gimple_phi_arg_def (phi, e->dest_idx); locus = gimple_phi_arg_location (phi, e->dest_idx); if (def == NULL_TREE) continue; redirect_edge_var_map_add (e, gimple_phi_result (phi), def, locus); } e = redirect_edge_succ_nodup (e, dest); return e; } /* Add PHI arguments queued in PENDING_STMT list on edge E to edge E->dest. */ void flush_pending_stmts (edge e) { gimple phi; edge_var_map_vector *v; edge_var_map *vm; int i; gimple_stmt_iterator gsi; v = redirect_edge_var_map_vector (e); if (!v) return; for (gsi = gsi_start_phis (e->dest), i = 0; !gsi_end_p (gsi) && v->iterate (i, &vm); gsi_next (&gsi), i++) { tree def; phi = gsi_stmt (gsi); def = redirect_edge_var_map_def (vm); add_phi_arg (phi, def, e, redirect_edge_var_map_location (vm)); } redirect_edge_var_map_clear (e); } /* Replace the LHS of STMT, an assignment, either a GIMPLE_ASSIGN or a GIMPLE_CALL, with NLHS, in preparation for modifying the RHS to an expression with a different value. This will update any annotations (say debug bind stmts) referring to the original LHS, so that they use the RHS instead. This is done even if NLHS and LHS are the same, for it is understood that the RHS will be modified afterwards, and NLHS will not be assigned an equivalent value. Adjusting any non-annotation uses of the LHS, if needed, is a responsibility of the caller. The effect of this call should be pretty much the same as that of inserting a copy of STMT before STMT, and then removing the original stmt, at which time gsi_remove() would have update annotations, but using this function saves all the inserting, copying and removing. */ void gimple_replace_ssa_lhs (gimple stmt, tree nlhs) { if (MAY_HAVE_DEBUG_STMTS) { tree lhs = gimple_get_lhs (stmt); gcc_assert (SSA_NAME_DEF_STMT (lhs) == stmt); insert_debug_temp_for_var_def (NULL, lhs); } gimple_set_lhs (stmt, nlhs); } /* Given a tree for an expression for which we might want to emit locations or values in debug information (generally a variable, but we might deal with other kinds of trees in the future), return the tree that should be used as the variable of a DEBUG_BIND STMT or VAR_LOCATION INSN or NOTE. Return NULL if VAR is not to be tracked. */ tree target_for_debug_bind (tree var) { if (!MAY_HAVE_DEBUG_STMTS) return NULL_TREE; if (TREE_CODE (var) == SSA_NAME) { var = SSA_NAME_VAR (var); if (var == NULL_TREE) return NULL_TREE; } if ((TREE_CODE (var) != VAR_DECL || VAR_DECL_IS_VIRTUAL_OPERAND (var)) && TREE_CODE (var) != PARM_DECL) return NULL_TREE; if (DECL_HAS_VALUE_EXPR_P (var)) return target_for_debug_bind (DECL_VALUE_EXPR (var)); if (DECL_IGNORED_P (var)) return NULL_TREE; /* var-tracking only tracks registers. */ if (!is_gimple_reg_type (TREE_TYPE (var))) return NULL_TREE; return var; } /* Called via walk_tree, look for SSA_NAMEs that have already been released. */ static tree find_released_ssa_name (tree *tp, int *walk_subtrees, void *data_) { struct walk_stmt_info *wi = (struct walk_stmt_info *) data_; if (wi && wi->is_lhs) return NULL_TREE; if (TREE_CODE (*tp) == SSA_NAME) { if (SSA_NAME_IN_FREE_LIST (*tp)) return *tp; *walk_subtrees = 0; } else if (IS_TYPE_OR_DECL_P (*tp)) *walk_subtrees = 0; return NULL_TREE; } /* Insert a DEBUG BIND stmt before the DEF of VAR if VAR is referenced by other DEBUG stmts, and replace uses of the DEF with the newly-created debug temp. */ void insert_debug_temp_for_var_def (gimple_stmt_iterator *gsi, tree var) { imm_use_iterator imm_iter; use_operand_p use_p; gimple stmt; gimple def_stmt = NULL; int usecount = 0; tree value = NULL; if (!MAY_HAVE_DEBUG_STMTS) return; /* If this name has already been registered for replacement, do nothing as anything that uses this name isn't in SSA form. */ if (name_registered_for_update_p (var)) return; /* Check whether there are debug stmts that reference this variable and, if there are, decide whether we should use a debug temp. */ FOR_EACH_IMM_USE_FAST (use_p, imm_iter, var) { stmt = USE_STMT (use_p); if (!gimple_debug_bind_p (stmt)) continue; if (usecount++) break; if (gimple_debug_bind_get_value (stmt) != var) { /* Count this as an additional use, so as to make sure we use a temp unless VAR's definition has a SINGLE_RHS that can be shared. */ usecount++; break; } } if (!usecount) return; if (gsi) def_stmt = gsi_stmt (*gsi); else def_stmt = SSA_NAME_DEF_STMT (var); /* If we didn't get an insertion point, and the stmt has already been removed, we won't be able to insert the debug bind stmt, so we'll have to drop debug information. */ if (gimple_code (def_stmt) == GIMPLE_PHI) { value = degenerate_phi_result (def_stmt); if (value && walk_tree (&value, find_released_ssa_name, NULL, NULL)) value = NULL; /* error_mark_node is what fixup_noreturn_call changes PHI arguments to. */ else if (value == error_mark_node) value = NULL; } else if (is_gimple_assign (def_stmt)) { bool no_value = false; if (!dom_info_available_p (CDI_DOMINATORS)) { struct walk_stmt_info wi; memset (&wi, 0, sizeof (wi)); /* When removing blocks without following reverse dominance order, we may sometimes encounter SSA_NAMEs that have already been released, referenced in other SSA_DEFs that we're about to release. Consider: : v_1 = foo; : w_2 = v_1 + bar; # DEBUG w => w_2 If we deleted BB X first, propagating the value of w_2 won't do us any good. It's too late to recover their original definition of v_1: when it was deleted, it was only referenced in other DEFs, it couldn't possibly know it should have been retained, and propagating every single DEF just in case it might have to be propagated into a DEBUG STMT would probably be too wasteful. When dominator information is not readily available, we check for and accept some loss of debug information. But if it is available, there's no excuse for us to remove blocks in the wrong order, so we don't even check for dead SSA NAMEs. SSA verification shall catch any errors. */ if ((!gsi && !gimple_bb (def_stmt)) || walk_gimple_op (def_stmt, find_released_ssa_name, &wi)) no_value = true; } if (!no_value) value = gimple_assign_rhs_to_tree (def_stmt); } if (value) { /* If there's a single use of VAR, and VAR is the entire debug expression (usecount would have been incremented again otherwise), and the definition involves only constants and SSA names, then we can propagate VALUE into this single use, avoiding the temp. We can also avoid using a temp if VALUE can be shared and propagated into all uses, without generating expressions that wouldn't be valid gimple RHSs. Other cases that would require unsharing or non-gimple RHSs are deferred to a debug temp, although we could avoid temps at the expense of duplication of expressions. */ if (CONSTANT_CLASS_P (value) || gimple_code (def_stmt) == GIMPLE_PHI || (usecount == 1 && (!gimple_assign_single_p (def_stmt) || is_gimple_min_invariant (value))) || is_gimple_reg (value)) ; else { gimple def_temp; tree vexpr = make_node (DEBUG_EXPR_DECL); def_temp = gimple_build_debug_bind (vexpr, unshare_expr (value), def_stmt); DECL_ARTIFICIAL (vexpr) = 1; TREE_TYPE (vexpr) = TREE_TYPE (value); if (DECL_P (value)) DECL_MODE (vexpr) = DECL_MODE (value); else DECL_MODE (vexpr) = TYPE_MODE (TREE_TYPE (value)); if (gsi) gsi_insert_before (gsi, def_temp, GSI_SAME_STMT); else { gimple_stmt_iterator ngsi = gsi_for_stmt (def_stmt); gsi_insert_before (&ngsi, def_temp, GSI_SAME_STMT); } value = vexpr; } } FOR_EACH_IMM_USE_STMT (stmt, imm_iter, var) { if (!gimple_debug_bind_p (stmt)) continue; if (value) { FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter) /* unshare_expr is not needed here. vexpr is either a SINGLE_RHS, that can be safely shared, some other RHS that was unshared when we found it had a single debug use, or a DEBUG_EXPR_DECL, that can be safely shared. */ SET_USE (use_p, unshare_expr (value)); /* If we didn't replace uses with a debug decl fold the resulting expression. Otherwise we end up with invalid IL. */ if (TREE_CODE (value) != DEBUG_EXPR_DECL) { gimple_stmt_iterator gsi = gsi_for_stmt (stmt); fold_stmt_inplace (&gsi); } } else gimple_debug_bind_reset_value (stmt); update_stmt (stmt); } } /* Insert a DEBUG BIND stmt before STMT for each DEF referenced by other DEBUG stmts, and replace uses of the DEF with the newly-created debug temp. */ void insert_debug_temps_for_defs (gimple_stmt_iterator *gsi) { gimple stmt; ssa_op_iter op_iter; def_operand_p def_p; if (!MAY_HAVE_DEBUG_STMTS) return; stmt = gsi_stmt (*gsi); FOR_EACH_PHI_OR_STMT_DEF (def_p, stmt, op_iter, SSA_OP_DEF) { tree var = DEF_FROM_PTR (def_p); if (TREE_CODE (var) != SSA_NAME) continue; insert_debug_temp_for_var_def (gsi, var); } } /* Reset all debug stmts that use SSA_NAME(s) defined in STMT. */ void reset_debug_uses (gimple stmt) { ssa_op_iter op_iter; def_operand_p def_p; imm_use_iterator imm_iter; gimple use_stmt; if (!MAY_HAVE_DEBUG_STMTS) return; FOR_EACH_PHI_OR_STMT_DEF (def_p, stmt, op_iter, SSA_OP_DEF) { tree var = DEF_FROM_PTR (def_p); if (TREE_CODE (var) != SSA_NAME) continue; FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, var) { if (!gimple_debug_bind_p (use_stmt)) continue; gimple_debug_bind_reset_value (use_stmt); update_stmt (use_stmt); } } } /* Delete SSA DEFs for SSA versions in the TOREMOVE bitmap, removing dominated stmts before their dominators, so that release_ssa_defs stands a chance of propagating DEFs into debug bind stmts. */ void release_defs_bitset (bitmap toremove) { unsigned j; bitmap_iterator bi; /* Performing a topological sort is probably overkill, this will most likely run in slightly superlinear time, rather than the pathological quadratic worst case. */ while (!bitmap_empty_p (toremove)) EXECUTE_IF_SET_IN_BITMAP (toremove, 0, j, bi) { bool remove_now = true; tree var = ssa_name (j); gimple stmt; imm_use_iterator uit; FOR_EACH_IMM_USE_STMT (stmt, uit, var) { ssa_op_iter dit; def_operand_p def_p; /* We can't propagate PHI nodes into debug stmts. */ if (gimple_code (stmt) == GIMPLE_PHI || is_gimple_debug (stmt)) continue; /* If we find another definition to remove that uses the one we're looking at, defer the removal of this one, so that it can be propagated into debug stmts after the other is. */ FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, dit, SSA_OP_DEF) { tree odef = DEF_FROM_PTR (def_p); if (bitmap_bit_p (toremove, SSA_NAME_VERSION (odef))) { remove_now = false; break; } } if (!remove_now) BREAK_FROM_IMM_USE_STMT (uit); } if (remove_now) { gimple def = SSA_NAME_DEF_STMT (var); gimple_stmt_iterator gsi = gsi_for_stmt (def); if (gimple_code (def) == GIMPLE_PHI) remove_phi_node (&gsi, true); else { gsi_remove (&gsi, true); release_defs (def); } bitmap_clear_bit (toremove, j); } } } /* Return true if SSA_NAME is malformed and mark it visited. IS_VIRTUAL is true if this SSA_NAME was found inside a virtual operand. */ static bool verify_ssa_name (tree ssa_name, bool is_virtual) { if (TREE_CODE (ssa_name) != SSA_NAME) { error ("expected an SSA_NAME object"); return true; } if (SSA_NAME_IN_FREE_LIST (ssa_name)) { error ("found an SSA_NAME that had been released into the free pool"); return true; } if (SSA_NAME_VAR (ssa_name) != NULL_TREE && TREE_TYPE (ssa_name) != TREE_TYPE (SSA_NAME_VAR (ssa_name))) { error ("type mismatch between an SSA_NAME and its symbol"); return true; } if (is_virtual && !virtual_operand_p (ssa_name)) { error ("found a virtual definition for a GIMPLE register"); return true; } if (is_virtual && SSA_NAME_VAR (ssa_name) != gimple_vop (cfun)) { error ("virtual SSA name for non-VOP decl"); return true; } if (!is_virtual && virtual_operand_p (ssa_name)) { error ("found a real definition for a non-register"); return true; } if (SSA_NAME_IS_DEFAULT_DEF (ssa_name) && !gimple_nop_p (SSA_NAME_DEF_STMT (ssa_name))) { error ("found a default name with a non-empty defining statement"); return true; } return false; } /* Return true if the definition of SSA_NAME at block BB is malformed. STMT is the statement where SSA_NAME is created. DEFINITION_BLOCK is an array of basic blocks indexed by SSA_NAME version numbers. If DEFINITION_BLOCK[SSA_NAME_VERSION] is set, it means that the block in that array slot contains the definition of SSA_NAME. IS_VIRTUAL is true if SSA_NAME is created by a VDEF. */ static bool verify_def (basic_block bb, basic_block *definition_block, tree ssa_name, gimple stmt, bool is_virtual) { if (verify_ssa_name (ssa_name, is_virtual)) goto err; if (SSA_NAME_VAR (ssa_name) && TREE_CODE (SSA_NAME_VAR (ssa_name)) == RESULT_DECL && DECL_BY_REFERENCE (SSA_NAME_VAR (ssa_name))) { error ("RESULT_DECL should be read only when DECL_BY_REFERENCE is set"); goto err; } if (definition_block[SSA_NAME_VERSION (ssa_name)]) { error ("SSA_NAME created in two different blocks %i and %i", definition_block[SSA_NAME_VERSION (ssa_name)]->index, bb->index); goto err; } definition_block[SSA_NAME_VERSION (ssa_name)] = bb; if (SSA_NAME_DEF_STMT (ssa_name) != stmt) { error ("SSA_NAME_DEF_STMT is wrong"); fprintf (stderr, "Expected definition statement:\n"); print_gimple_stmt (stderr, SSA_NAME_DEF_STMT (ssa_name), 4, TDF_VOPS); fprintf (stderr, "\nActual definition statement:\n"); print_gimple_stmt (stderr, stmt, 4, TDF_VOPS); goto err; } return false; err: fprintf (stderr, "while verifying SSA_NAME "); print_generic_expr (stderr, ssa_name, 0); fprintf (stderr, " in statement\n"); print_gimple_stmt (stderr, stmt, 4, TDF_VOPS); return true; } /* Return true if the use of SSA_NAME at statement STMT in block BB is malformed. DEF_BB is the block where SSA_NAME was found to be created. IDOM contains immediate dominator information for the flowgraph. CHECK_ABNORMAL is true if the caller wants to check whether this use is flowing through an abnormal edge (only used when checking PHI arguments). If NAMES_DEFINED_IN_BB is not NULL, it contains a bitmap of ssa names that are defined before STMT in basic block BB. */ static bool verify_use (basic_block bb, basic_block def_bb, use_operand_p use_p, gimple stmt, bool check_abnormal, bitmap names_defined_in_bb) { bool err = false; tree ssa_name = USE_FROM_PTR (use_p); if (!TREE_VISITED (ssa_name)) if (verify_imm_links (stderr, ssa_name)) err = true; TREE_VISITED (ssa_name) = 1; if (gimple_nop_p (SSA_NAME_DEF_STMT (ssa_name)) && SSA_NAME_IS_DEFAULT_DEF (ssa_name)) ; /* Default definitions have empty statements. Nothing to do. */ else if (!def_bb) { error ("missing definition"); err = true; } else if (bb != def_bb && !dominated_by_p (CDI_DOMINATORS, bb, def_bb)) { error ("definition in block %i does not dominate use in block %i", def_bb->index, bb->index); err = true; } else if (bb == def_bb && names_defined_in_bb != NULL && !bitmap_bit_p (names_defined_in_bb, SSA_NAME_VERSION (ssa_name))) { error ("definition in block %i follows the use", def_bb->index); err = true; } if (check_abnormal && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (ssa_name)) { error ("SSA_NAME_OCCURS_IN_ABNORMAL_PHI should be set"); err = true; } /* Make sure the use is in an appropriate list by checking the previous element to make sure it's the same. */ if (use_p->prev == NULL) { error ("no immediate_use list"); err = true; } else { tree listvar; if (use_p->prev->use == NULL) listvar = use_p->prev->loc.ssa_name; else listvar = USE_FROM_PTR (use_p->prev); if (listvar != ssa_name) { error ("wrong immediate use list"); err = true; } } if (err) { fprintf (stderr, "for SSA_NAME: "); print_generic_expr (stderr, ssa_name, TDF_VOPS); fprintf (stderr, " in statement:\n"); print_gimple_stmt (stderr, stmt, 0, TDF_VOPS); } return err; } /* Return true if any of the arguments for PHI node PHI at block BB is malformed. DEFINITION_BLOCK is an array of basic blocks indexed by SSA_NAME version numbers. If DEFINITION_BLOCK[SSA_NAME_VERSION] is set, it means that the block in that array slot contains the definition of SSA_NAME. */ static bool verify_phi_args (gimple phi, basic_block bb, basic_block *definition_block) { edge e; bool err = false; size_t i, phi_num_args = gimple_phi_num_args (phi); if (EDGE_COUNT (bb->preds) != phi_num_args) { error ("incoming edge count does not match number of PHI arguments"); err = true; goto error; } for (i = 0; i < phi_num_args; i++) { use_operand_p op_p = gimple_phi_arg_imm_use_ptr (phi, i); tree op = USE_FROM_PTR (op_p); e = EDGE_PRED (bb, i); if (op == NULL_TREE) { error ("PHI argument is missing for edge %d->%d", e->src->index, e->dest->index); err = true; goto error; } if (TREE_CODE (op) != SSA_NAME && !is_gimple_min_invariant (op)) { error ("PHI argument is not SSA_NAME, or invariant"); err = true; } if (TREE_CODE (op) == SSA_NAME) { err = verify_ssa_name (op, virtual_operand_p (gimple_phi_result (phi))); err |= verify_use (e->src, definition_block[SSA_NAME_VERSION (op)], op_p, phi, e->flags & EDGE_ABNORMAL, NULL); } if (TREE_CODE (op) == ADDR_EXPR) { tree base = TREE_OPERAND (op, 0); while (handled_component_p (base)) base = TREE_OPERAND (base, 0); if ((TREE_CODE (base) == VAR_DECL || TREE_CODE (base) == PARM_DECL || TREE_CODE (base) == RESULT_DECL) && !TREE_ADDRESSABLE (base)) { error ("address taken, but ADDRESSABLE bit not set"); err = true; } } if (e->dest != bb) { error ("wrong edge %d->%d for PHI argument", e->src->index, e->dest->index); err = true; } if (err) { fprintf (stderr, "PHI argument\n"); print_generic_stmt (stderr, op, TDF_VOPS); goto error; } } error: if (err) { fprintf (stderr, "for PHI node\n"); print_gimple_stmt (stderr, phi, 0, TDF_VOPS|TDF_MEMSYMS); } return err; } /* Verify common invariants in the SSA web. TODO: verify the variable annotations. */ DEBUG_FUNCTION void verify_ssa (bool check_modified_stmt) { size_t i; basic_block bb; basic_block *definition_block = XCNEWVEC (basic_block, num_ssa_names); ssa_op_iter iter; tree op; enum dom_state orig_dom_state = dom_info_state (CDI_DOMINATORS); bitmap names_defined_in_bb = BITMAP_ALLOC (NULL); gcc_assert (!need_ssa_update_p (cfun)); timevar_push (TV_TREE_SSA_VERIFY); /* Keep track of SSA names present in the IL. */ for (i = 1; i < num_ssa_names; i++) { tree name = ssa_name (i); if (name) { gimple stmt; TREE_VISITED (name) = 0; verify_ssa_name (name, virtual_operand_p (name)); stmt = SSA_NAME_DEF_STMT (name); if (!gimple_nop_p (stmt)) { basic_block bb = gimple_bb (stmt); verify_def (bb, definition_block, name, stmt, virtual_operand_p (name)); } } } calculate_dominance_info (CDI_DOMINATORS); /* Now verify all the uses and make sure they agree with the definitions found in the previous pass. */ FOR_EACH_BB_FN (bb, cfun) { edge e; gimple phi; edge_iterator ei; gimple_stmt_iterator gsi; /* Make sure that all edges have a clear 'aux' field. */ FOR_EACH_EDGE (e, ei, bb->preds) { if (e->aux) { error ("AUX pointer initialized for edge %d->%d", e->src->index, e->dest->index); goto err; } } /* Verify the arguments for every PHI node in the block. */ for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) { phi = gsi_stmt (gsi); if (verify_phi_args (phi, bb, definition_block)) goto err; bitmap_set_bit (names_defined_in_bb, SSA_NAME_VERSION (gimple_phi_result (phi))); } /* Now verify all the uses and vuses in every statement of the block. */ for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) { gimple stmt = gsi_stmt (gsi); use_operand_p use_p; if (check_modified_stmt && gimple_modified_p (stmt)) { error ("stmt (%p) marked modified after optimization pass: ", (void *)stmt); print_gimple_stmt (stderr, stmt, 0, TDF_VOPS); goto err; } if (verify_ssa_operands (cfun, stmt)) { print_gimple_stmt (stderr, stmt, 0, TDF_VOPS); goto err; } if (gimple_debug_bind_p (stmt) && !gimple_debug_bind_has_value_p (stmt)) continue; FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE|SSA_OP_VUSE) { op = USE_FROM_PTR (use_p); if (verify_use (bb, definition_block[SSA_NAME_VERSION (op)], use_p, stmt, false, names_defined_in_bb)) goto err; } FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_ALL_DEFS) { if (SSA_NAME_DEF_STMT (op) != stmt) { error ("SSA_NAME_DEF_STMT is wrong"); fprintf (stderr, "Expected definition statement:\n"); print_gimple_stmt (stderr, stmt, 4, TDF_VOPS); fprintf (stderr, "\nActual definition statement:\n"); print_gimple_stmt (stderr, SSA_NAME_DEF_STMT (op), 4, TDF_VOPS); goto err; } bitmap_set_bit (names_defined_in_bb, SSA_NAME_VERSION (op)); } } bitmap_clear (names_defined_in_bb); } free (definition_block); /* Restore the dominance information to its prior known state, so that we do not perturb the compiler's subsequent behavior. */ if (orig_dom_state == DOM_NONE) free_dominance_info (CDI_DOMINATORS); else set_dom_info_availability (CDI_DOMINATORS, orig_dom_state); BITMAP_FREE (names_defined_in_bb); timevar_pop (TV_TREE_SSA_VERIFY); return; err: internal_error ("verify_ssa failed"); } /* Return true if the DECL_UID in both trees are equal. */ static int uid_ssaname_map_eq (const void *va, const void *vb) { const_tree a = (const_tree) va; const_tree b = (const_tree) vb; return (a->ssa_name.var->decl_minimal.uid == b->ssa_name.var->decl_minimal.uid); } /* Hash a tree in a uid_decl_map. */ static unsigned int uid_ssaname_map_hash (const void *item) { return ((const_tree)item)->ssa_name.var->decl_minimal.uid; } /* Initialize global DFA and SSA structures. */ void init_tree_ssa (struct function *fn) { fn->gimple_df = ggc_alloc_cleared_gimple_df (); fn->gimple_df->default_defs = htab_create_ggc (20, uid_ssaname_map_hash, uid_ssaname_map_eq, NULL); pt_solution_reset (&fn->gimple_df->escaped); init_ssanames (fn, 0); } /* Do the actions required to initialize internal data structures used in tree-ssa optimization passes. */ static unsigned int execute_init_datastructures (void) { /* Allocate hash tables, arrays and other structures. */ gcc_assert (!cfun->gimple_df); init_tree_ssa (cfun); return 0; } /* Gate for IPCP optimization. */ static bool gate_init_datastructures (void) { /* Do nothing for funcions that was produced already in SSA form. */ return !(cfun->curr_properties & PROP_ssa); } namespace { const pass_data pass_data_init_datastructures = { GIMPLE_PASS, /* type */ "*init_datastructures", /* name */ OPTGROUP_NONE, /* optinfo_flags */ true, /* has_gate */ true, /* has_execute */ TV_NONE, /* tv_id */ PROP_cfg, /* properties_required */ 0, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ 0, /* todo_flags_finish */ }; class pass_init_datastructures : public gimple_opt_pass { public: pass_init_datastructures (gcc::context *ctxt) : gimple_opt_pass (pass_data_init_datastructures, ctxt) {} /* opt_pass methods: */ bool gate () { return gate_init_datastructures (); } unsigned int execute () { return execute_init_datastructures (); } }; // class pass_init_datastructures } // anon namespace gimple_opt_pass * make_pass_init_datastructures (gcc::context *ctxt) { return new pass_init_datastructures (ctxt); } /* Deallocate memory associated with SSA data structures for FNDECL. */ void delete_tree_ssa (void) { fini_ssanames (); /* We no longer maintain the SSA operand cache at this point. */ if (ssa_operands_active (cfun)) fini_ssa_operands (cfun); htab_delete (cfun->gimple_df->default_defs); cfun->gimple_df->default_defs = NULL; pt_solution_reset (&cfun->gimple_df->escaped); if (cfun->gimple_df->decls_to_pointers != NULL) pointer_map_destroy (cfun->gimple_df->decls_to_pointers); cfun->gimple_df->decls_to_pointers = NULL; cfun->gimple_df->modified_noreturn_calls = NULL; cfun->gimple_df = NULL; /* We no longer need the edge variable maps. */ redirect_edge_var_map_destroy (); } /* Return true if EXPR is a useless type conversion, otherwise return false. */ bool tree_ssa_useless_type_conversion (tree expr) { /* If we have an assignment that merely uses a NOP_EXPR to change the top of the RHS to the type of the LHS and the type conversion is "safe", then strip away the type conversion so that we can enter LHS = RHS into the const_and_copies table. */ if (CONVERT_EXPR_P (expr) || TREE_CODE (expr) == VIEW_CONVERT_EXPR || TREE_CODE (expr) == NON_LVALUE_EXPR) return useless_type_conversion_p (TREE_TYPE (expr), TREE_TYPE (TREE_OPERAND (expr, 0))); return false; } /* Strip conversions from EXP according to tree_ssa_useless_type_conversion and return the resulting expression. */ tree tree_ssa_strip_useless_type_conversions (tree exp) { while (tree_ssa_useless_type_conversion (exp)) exp = TREE_OPERAND (exp, 0); return exp; } /* Return true if T, an SSA_NAME, has an undefined value. */ bool ssa_undefined_value_p (tree t) { tree var = SSA_NAME_VAR (t); if (!var) ; /* Parameters get their initial value from the function entry. */ else if (TREE_CODE (var) == PARM_DECL) return false; /* When returning by reference the return address is actually a hidden parameter. */ else if (TREE_CODE (var) == RESULT_DECL && DECL_BY_REFERENCE (var)) return false; /* Hard register variables get their initial value from the ether. */ else if (TREE_CODE (var) == VAR_DECL && DECL_HARD_REGISTER (var)) return false; /* The value is undefined iff its definition statement is empty. */ return gimple_nop_p (SSA_NAME_DEF_STMT (t)); } /* If necessary, rewrite the base of the reference tree *TP from a MEM_REF to a plain or converted symbol. */ static void maybe_rewrite_mem_ref_base (tree *tp, bitmap suitable_for_renaming) { tree sym; while (handled_component_p (*tp)) tp = &TREE_OPERAND (*tp, 0); if (TREE_CODE (*tp) == MEM_REF && TREE_CODE (TREE_OPERAND (*tp, 0)) == ADDR_EXPR && (sym = TREE_OPERAND (TREE_OPERAND (*tp, 0), 0)) && DECL_P (sym) && !TREE_ADDRESSABLE (sym) && bitmap_bit_p (suitable_for_renaming, DECL_UID (sym))) { if (TREE_CODE (TREE_TYPE (sym)) == VECTOR_TYPE && useless_type_conversion_p (TREE_TYPE (*tp), TREE_TYPE (TREE_TYPE (sym))) && multiple_of_p (sizetype, TREE_OPERAND (*tp, 1), TYPE_SIZE_UNIT (TREE_TYPE (*tp)))) { *tp = build3 (BIT_FIELD_REF, TREE_TYPE (*tp), sym, TYPE_SIZE (TREE_TYPE (*tp)), int_const_binop (MULT_EXPR, bitsize_int (BITS_PER_UNIT), TREE_OPERAND (*tp, 1))); } else if (TREE_CODE (TREE_TYPE (sym)) == COMPLEX_TYPE && useless_type_conversion_p (TREE_TYPE (*tp), TREE_TYPE (TREE_TYPE (sym)))) { *tp = build1 (integer_zerop (TREE_OPERAND (*tp, 1)) ? REALPART_EXPR : IMAGPART_EXPR, TREE_TYPE (*tp), sym); } else if (integer_zerop (TREE_OPERAND (*tp, 1))) { if (!useless_type_conversion_p (TREE_TYPE (*tp), TREE_TYPE (sym))) *tp = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (*tp), sym); else *tp = sym; } } } /* For a tree REF return its base if it is the base of a MEM_REF that cannot be rewritten into SSA form. Otherwise return NULL_TREE. */ static tree non_rewritable_mem_ref_base (tree ref) { tree base = ref; /* A plain decl does not need it set. */ if (DECL_P (ref)) return NULL_TREE; while (handled_component_p (base)) base = TREE_OPERAND (base, 0); /* But watch out for MEM_REFs we cannot lower to a VIEW_CONVERT_EXPR or a BIT_FIELD_REF. */ if (TREE_CODE (base) == MEM_REF && TREE_CODE (TREE_OPERAND (base, 0)) == ADDR_EXPR) { tree decl = TREE_OPERAND (TREE_OPERAND (base, 0), 0); if ((TREE_CODE (TREE_TYPE (decl)) == VECTOR_TYPE || TREE_CODE (TREE_TYPE (decl)) == COMPLEX_TYPE) && useless_type_conversion_p (TREE_TYPE (base), TREE_TYPE (TREE_TYPE (decl))) && mem_ref_offset (base).fits_uhwi () && tree_to_double_int (TYPE_SIZE_UNIT (TREE_TYPE (decl))) .ugt (mem_ref_offset (base)) && multiple_of_p (sizetype, TREE_OPERAND (base, 1), TYPE_SIZE_UNIT (TREE_TYPE (base)))) return NULL_TREE; if (DECL_P (decl) && (!integer_zerop (TREE_OPERAND (base, 1)) || (DECL_SIZE (decl) != TYPE_SIZE (TREE_TYPE (base))) || TREE_THIS_VOLATILE (decl) != TREE_THIS_VOLATILE (base))) return decl; } return NULL_TREE; } /* For an lvalue tree LHS return true if it cannot be rewritten into SSA form. Otherwise return true. */ static bool non_rewritable_lvalue_p (tree lhs) { /* A plain decl is always rewritable. */ if (DECL_P (lhs)) return false; /* A decl that is wrapped inside a MEM-REF that covers it full is also rewritable. ??? The following could be relaxed allowing component references that do not change the access size. */ if (TREE_CODE (lhs) == MEM_REF && TREE_CODE (TREE_OPERAND (lhs, 0)) == ADDR_EXPR && integer_zerop (TREE_OPERAND (lhs, 1))) { tree decl = TREE_OPERAND (TREE_OPERAND (lhs, 0), 0); if (DECL_P (decl) && DECL_SIZE (decl) == TYPE_SIZE (TREE_TYPE (lhs)) && (TREE_THIS_VOLATILE (decl) == TREE_THIS_VOLATILE (lhs))) return false; } return true; } /* When possible, clear TREE_ADDRESSABLE bit or set DECL_GIMPLE_REG_P bit and mark the variable VAR for conversion into SSA. Return true when updating stmts is required. */ static void maybe_optimize_var (tree var, bitmap addresses_taken, bitmap not_reg_needs, bitmap suitable_for_renaming) { /* Global Variables, result decls cannot be changed. */ if (is_global_var (var) || TREE_CODE (var) == RESULT_DECL || bitmap_bit_p (addresses_taken, DECL_UID (var))) return; if (TREE_ADDRESSABLE (var) /* Do not change TREE_ADDRESSABLE if we need to preserve var as a non-register. Otherwise we are confused and forget to add virtual operands for it. */ && (!is_gimple_reg_type (TREE_TYPE (var)) || TREE_CODE (TREE_TYPE (var)) == VECTOR_TYPE || TREE_CODE (TREE_TYPE (var)) == COMPLEX_TYPE || !bitmap_bit_p (not_reg_needs, DECL_UID (var)))) { TREE_ADDRESSABLE (var) = 0; if (is_gimple_reg (var)) bitmap_set_bit (suitable_for_renaming, DECL_UID (var)); if (dump_file) { fprintf (dump_file, "No longer having address taken: "); print_generic_expr (dump_file, var, 0); fprintf (dump_file, "\n"); } } if (!DECL_GIMPLE_REG_P (var) && !bitmap_bit_p (not_reg_needs, DECL_UID (var)) && (TREE_CODE (TREE_TYPE (var)) == COMPLEX_TYPE || TREE_CODE (TREE_TYPE (var)) == VECTOR_TYPE) && !TREE_THIS_VOLATILE (var) && (TREE_CODE (var) != VAR_DECL || !DECL_HARD_REGISTER (var))) { DECL_GIMPLE_REG_P (var) = 1; bitmap_set_bit (suitable_for_renaming, DECL_UID (var)); if (dump_file) { fprintf (dump_file, "Now a gimple register: "); print_generic_expr (dump_file, var, 0); fprintf (dump_file, "\n"); } } } /* Compute TREE_ADDRESSABLE and DECL_GIMPLE_REG_P for local variables. */ void execute_update_addresses_taken (void) { gimple_stmt_iterator gsi; basic_block bb; bitmap addresses_taken = BITMAP_ALLOC (NULL); bitmap not_reg_needs = BITMAP_ALLOC (NULL); bitmap suitable_for_renaming = BITMAP_ALLOC (NULL); tree var; unsigned i; timevar_push (TV_ADDRESS_TAKEN); /* Collect into ADDRESSES_TAKEN all variables whose address is taken within the function body. */ FOR_EACH_BB_FN (bb, cfun) { for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) { gimple stmt = gsi_stmt (gsi); enum gimple_code code = gimple_code (stmt); tree decl; /* Note all addresses taken by the stmt. */ gimple_ior_addresses_taken (addresses_taken, stmt); /* If we have a call or an assignment, see if the lhs contains a local decl that requires not to be a gimple register. */ if (code == GIMPLE_ASSIGN || code == GIMPLE_CALL) { tree lhs = gimple_get_lhs (stmt); if (lhs && TREE_CODE (lhs) != SSA_NAME && non_rewritable_lvalue_p (lhs)) { decl = get_base_address (lhs); if (DECL_P (decl)) bitmap_set_bit (not_reg_needs, DECL_UID (decl)); } } if (gimple_assign_single_p (stmt)) { tree rhs = gimple_assign_rhs1 (stmt); if ((decl = non_rewritable_mem_ref_base (rhs))) bitmap_set_bit (not_reg_needs, DECL_UID (decl)); } else if (code == GIMPLE_CALL) { for (i = 0; i < gimple_call_num_args (stmt); ++i) { tree arg = gimple_call_arg (stmt, i); if ((decl = non_rewritable_mem_ref_base (arg))) bitmap_set_bit (not_reg_needs, DECL_UID (decl)); } } else if (code == GIMPLE_ASM) { for (i = 0; i < gimple_asm_noutputs (stmt); ++i) { tree link = gimple_asm_output_op (stmt, i); tree lhs = TREE_VALUE (link); if (TREE_CODE (lhs) != SSA_NAME) { decl = get_base_address (lhs); if (DECL_P (decl) && (non_rewritable_lvalue_p (lhs) /* We cannot move required conversions from the lhs to the rhs in asm statements, so require we do not need any. */ || !useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (decl)))) bitmap_set_bit (not_reg_needs, DECL_UID (decl)); } } for (i = 0; i < gimple_asm_ninputs (stmt); ++i) { tree link = gimple_asm_input_op (stmt, i); if ((decl = non_rewritable_mem_ref_base (TREE_VALUE (link)))) bitmap_set_bit (not_reg_needs, DECL_UID (decl)); } } } for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) { size_t i; gimple phi = gsi_stmt (gsi); for (i = 0; i < gimple_phi_num_args (phi); i++) { tree op = PHI_ARG_DEF (phi, i), var; if (TREE_CODE (op) == ADDR_EXPR && (var = get_base_address (TREE_OPERAND (op, 0))) != NULL && DECL_P (var)) bitmap_set_bit (addresses_taken, DECL_UID (var)); } } } /* We cannot iterate over all referenced vars because that can contain unused vars from BLOCK trees, which causes code generation differences for -g vs. -g0. */ for (var = DECL_ARGUMENTS (cfun->decl); var; var = DECL_CHAIN (var)) maybe_optimize_var (var, addresses_taken, not_reg_needs, suitable_for_renaming); FOR_EACH_VEC_SAFE_ELT (cfun->local_decls, i, var) maybe_optimize_var (var, addresses_taken, not_reg_needs, suitable_for_renaming); /* Operand caches need to be recomputed for operands referencing the updated variables and operands need to be rewritten to expose bare symbols. */ if (!bitmap_empty_p (suitable_for_renaming)) { FOR_EACH_BB_FN (bb, cfun) for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi);) { gimple stmt = gsi_stmt (gsi); /* Re-write TARGET_MEM_REFs of symbols we want to rewrite into SSA form. */ if (gimple_assign_single_p (stmt)) { tree lhs = gimple_assign_lhs (stmt); tree rhs, *rhsp = gimple_assign_rhs1_ptr (stmt); tree sym; /* We shouldn't have any fancy wrapping of component-refs on the LHS, but look through VIEW_CONVERT_EXPRs as that is easy. */ while (TREE_CODE (lhs) == VIEW_CONVERT_EXPR) lhs = TREE_OPERAND (lhs, 0); if (TREE_CODE (lhs) == MEM_REF && TREE_CODE (TREE_OPERAND (lhs, 0)) == ADDR_EXPR && integer_zerop (TREE_OPERAND (lhs, 1)) && (sym = TREE_OPERAND (TREE_OPERAND (lhs, 0), 0)) && DECL_P (sym) && !TREE_ADDRESSABLE (sym) && bitmap_bit_p (suitable_for_renaming, DECL_UID (sym))) lhs = sym; else lhs = gimple_assign_lhs (stmt); /* Rewrite the RHS and make sure the resulting assignment is validly typed. */ maybe_rewrite_mem_ref_base (rhsp, suitable_for_renaming); rhs = gimple_assign_rhs1 (stmt); if (gimple_assign_lhs (stmt) != lhs && !useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs))) rhs = fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (lhs), rhs); if (gimple_assign_lhs (stmt) != lhs) gimple_assign_set_lhs (stmt, lhs); /* For var ={v} {CLOBBER}; where var lost TREE_ADDRESSABLE just remove the stmt. */ if (DECL_P (lhs) && TREE_CLOBBER_P (rhs) && bitmap_bit_p (suitable_for_renaming, DECL_UID (lhs))) { unlink_stmt_vdef (stmt); gsi_remove (&gsi, true); release_defs (stmt); continue; } if (gimple_assign_rhs1 (stmt) != rhs) { gimple_stmt_iterator gsi = gsi_for_stmt (stmt); gimple_assign_set_rhs_from_tree (&gsi, rhs); } } else if (gimple_code (stmt) == GIMPLE_CALL) { unsigned i; for (i = 0; i < gimple_call_num_args (stmt); ++i) { tree *argp = gimple_call_arg_ptr (stmt, i); maybe_rewrite_mem_ref_base (argp, suitable_for_renaming); } } else if (gimple_code (stmt) == GIMPLE_ASM) { unsigned i; for (i = 0; i < gimple_asm_noutputs (stmt); ++i) { tree link = gimple_asm_output_op (stmt, i); maybe_rewrite_mem_ref_base (&TREE_VALUE (link), suitable_for_renaming); } for (i = 0; i < gimple_asm_ninputs (stmt); ++i) { tree link = gimple_asm_input_op (stmt, i); maybe_rewrite_mem_ref_base (&TREE_VALUE (link), suitable_for_renaming); } } else if (gimple_debug_bind_p (stmt) && gimple_debug_bind_has_value_p (stmt)) { tree *valuep = gimple_debug_bind_get_value_ptr (stmt); tree decl; maybe_rewrite_mem_ref_base (valuep, suitable_for_renaming); decl = non_rewritable_mem_ref_base (*valuep); if (decl && bitmap_bit_p (suitable_for_renaming, DECL_UID (decl))) gimple_debug_bind_reset_value (stmt); } if (gimple_references_memory_p (stmt) || is_gimple_debug (stmt)) update_stmt (stmt); gsi_next (&gsi); } /* Update SSA form here, we are called as non-pass as well. */ if (number_of_loops (cfun) > 1 && loops_state_satisfies_p (LOOP_CLOSED_SSA)) rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa); else update_ssa (TODO_update_ssa); } BITMAP_FREE (not_reg_needs); BITMAP_FREE (addresses_taken); BITMAP_FREE (suitable_for_renaming); timevar_pop (TV_ADDRESS_TAKEN); } namespace { const pass_data pass_data_update_address_taken = { GIMPLE_PASS, /* type */ "addressables", /* name */ OPTGROUP_NONE, /* optinfo_flags */ false, /* has_gate */ false, /* has_execute */ TV_ADDRESS_TAKEN, /* tv_id */ PROP_ssa, /* properties_required */ 0, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ TODO_update_address_taken, /* todo_flags_finish */ }; class pass_update_address_taken : public gimple_opt_pass { public: pass_update_address_taken (gcc::context *ctxt) : gimple_opt_pass (pass_data_update_address_taken, ctxt) {} /* opt_pass methods: */ }; // class pass_update_address_taken } // anon namespace gimple_opt_pass * make_pass_update_address_taken (gcc::context *ctxt) { return new pass_update_address_taken (ctxt); }