X-Git-Url: http://git.sourceforge.jp/view?a=blobdiff_plain;f=gcc%2Ftree-ssa.c;h=dfea0258ea19f623b7eeb69a1a4bb1f4cd6b73e7;hb=d5d9c11ab5f82df9cbd2baf594bd59dc1a3f2f91;hp=51b1689912115fb07297b28cc91ca70461ff36c7;hpb=a8cefe905b366aaa6b6af15a9f7124153ed18cf3;p=pf3gnuchains%2Fgcc-fork.git diff --git a/gcc/tree-ssa.c b/gcc/tree-ssa.c index 51b16899121..dfea0258ea1 100644 --- a/gcc/tree-ssa.c +++ b/gcc/tree-ssa.c @@ -1,5 +1,5 @@ /* Miscellaneous SSA utility functions. - Copyright (C) 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009 + Copyright (C) 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010 Free Software Foundation, Inc. This file is part of GCC. @@ -24,23 +24,22 @@ along with GCC; see the file COPYING3. If not see #include "tm.h" #include "tree.h" #include "flags.h" -#include "rtl.h" #include "tm_p.h" #include "target.h" #include "ggc.h" #include "langhooks.h" -#include "hard-reg-set.h" #include "basic-block.h" #include "output.h" #include "expr.h" #include "function.h" #include "diagnostic.h" +#include "tree-pretty-print.h" +#include "gimple-pretty-print.h" #include "bitmap.h" #include "pointer-set.h" #include "tree-flow.h" #include "gimple.h" #include "tree-inline.h" -#include "varray.h" #include "timevar.h" #include "hashtab.h" #include "tree-dump.h" @@ -243,6 +242,331 @@ flush_pending_stmts (edge e) redirect_edge_var_map_clear (e); } +/* 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) != VAR_DECL + && 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; + + if (!is_gimple_reg (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; + } + 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)) + value = unshare_expr (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, value); + 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); + } +} + +/* 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 @@ -404,7 +728,7 @@ verify_use (basic_block bb, basic_block def_bb, use_operand_p use_p, err = true; } - /* Make sure the use is in an appropriate list by checking the previous + /* 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) { @@ -636,6 +960,9 @@ verify_ssa (bool check_modified_stmt) goto err; } } + else if (gimple_debug_bind_p (stmt) + && !gimple_debug_bind_has_value_p (stmt)) + continue; /* Verify the single virtual operand and its constraints. */ has_err = false; @@ -720,7 +1047,7 @@ verify_ssa (bool check_modified_stmt) 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; @@ -790,12 +1117,11 @@ void init_tree_ssa (struct function *fn) { fn->gimple_df = GGC_CNEW (struct gimple_df); - fn->gimple_df->referenced_vars = htab_create_ggc (20, uid_decl_map_hash, + fn->gimple_df->referenced_vars = htab_create_ggc (20, uid_decl_map_hash, uid_decl_map_eq, NULL); - fn->gimple_df->default_defs = htab_create_ggc (20, uid_ssaname_map_hash, + 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); - pt_solution_reset (&fn->gimple_df->callused); init_ssanames (fn, 0); init_phinodes (); } @@ -814,9 +1140,11 @@ delete_tree_ssa (void) { if (is_global_var (var)) continue; - if (var->base.ann) - ggc_free (var->base.ann); - var->base.ann = NULL; + if (var_ann (var)) + { + ggc_free (var_ann (var)); + *DECL_VAR_ANN_PTR (var) = NULL; + } } htab_delete (gimple_referenced_vars (cfun)); cfun->gimple_df->referenced_vars = NULL; @@ -833,7 +1161,6 @@ delete_tree_ssa (void) htab_delete (cfun->gimple_df->default_defs); cfun->gimple_df->default_defs = NULL; pt_solution_reset (&cfun->gimple_df->escaped); - pt_solution_reset (&cfun->gimple_df->callused); if (cfun->gimple_df->decls_to_pointers != NULL) pointer_map_destroy (cfun->gimple_df->decls_to_pointers); cfun->gimple_df->decls_to_pointers = NULL; @@ -874,15 +1201,15 @@ useless_type_conversion_p (tree outer_type, tree inner_type) if (POINTER_TYPE_P (inner_type) && POINTER_TYPE_P (outer_type)) { + /* Do not lose casts between pointers to different address spaces. */ + if (TYPE_ADDR_SPACE (TREE_TYPE (outer_type)) + != TYPE_ADDR_SPACE (TREE_TYPE (inner_type))) + return false; + /* If the outer type is (void *) or a pointer to an incomplete record type or a pointer to an unprototyped function, then the conversion is not necessary. */ if (VOID_TYPE_P (TREE_TYPE (outer_type)) - || (AGGREGATE_TYPE_P (TREE_TYPE (outer_type)) - && TREE_CODE (TREE_TYPE (outer_type)) != ARRAY_TYPE - && (TREE_CODE (TREE_TYPE (outer_type)) - == TREE_CODE (TREE_TYPE (inner_type))) - && !COMPLETE_TYPE_P (TREE_TYPE (outer_type))) || ((TREE_CODE (TREE_TYPE (outer_type)) == FUNCTION_TYPE || TREE_CODE (TREE_TYPE (outer_type)) == METHOD_TYPE) && (TREE_CODE (TREE_TYPE (outer_type)) @@ -1085,7 +1412,8 @@ useless_type_conversion_p (tree outer_type, tree inner_type) if (!TYPE_ARG_TYPES (outer_type)) return true; - /* If the argument types are compatible the conversion is useless. */ + /* If the unqualified argument types are compatible the conversion + is useless. */ if (TYPE_ARG_TYPES (outer_type) == TYPE_ARG_TYPES (inner_type)) return true; @@ -1094,8 +1422,9 @@ useless_type_conversion_p (tree outer_type, tree inner_type) outer_parm && inner_parm; outer_parm = TREE_CHAIN (outer_parm), inner_parm = TREE_CHAIN (inner_parm)) - if (!useless_type_conversion_p (TREE_VALUE (outer_parm), - TREE_VALUE (inner_parm))) + if (!useless_type_conversion_p + (TYPE_MAIN_VARIANT (TREE_VALUE (outer_parm)), + TYPE_MAIN_VARIANT (TREE_VALUE (inner_parm)))) return false; /* If there is a mismatch in the number of arguments the functions @@ -1116,7 +1445,7 @@ useless_type_conversion_p (tree outer_type, tree inner_type) else if (AGGREGATE_TYPE_P (inner_type) && TREE_CODE (inner_type) == TREE_CODE (outer_type)) return false; - + return false; } @@ -1166,7 +1495,7 @@ tree_ssa_strip_useless_type_conversions (tree exp) /* Internal helper for walk_use_def_chains. VAR, FN and DATA are as described in walk_use_def_chains. - + VISITED is a pointer set used to mark visited SSA_NAMEs to avoid infinite loops. We used to have a bitmap for this to just mark SSA versions we had visited. But non-sparse bitmaps are way too @@ -1224,10 +1553,10 @@ walk_use_def_chains_1 (tree var, walk_use_def_chains_fn fn, void *data, if (fn (gimple_phi_arg_def (def_stmt, i), def_stmt, data)) return true; } - + return false; } - + /* Walk use-def chains starting at the SSA variable VAR. Call @@ -1235,7 +1564,7 @@ walk_use_def_chains_1 (tree var, walk_use_def_chains_fn fn, void *data, arguments: VAR, its defining statement (DEF_STMT) and a generic pointer to whatever state information that FN may want to maintain (DATA). FN is able to stop the walk by returning true, otherwise - in order to continue the walk, FN should return false. + in order to continue the walk, FN should return false. Note, that if DEF_STMT is a PHI node, the semantics are slightly different. The first argument to FN is no longer the original @@ -1273,25 +1602,6 @@ walk_use_def_chains (tree var, walk_use_def_chains_fn fn, void *data, } -/* Return true if T, an SSA_NAME, has an undefined value. */ - -bool -ssa_undefined_value_p (tree t) -{ - tree var = SSA_NAME_VAR (t); - - /* Parameters get their initial value from the function entry. */ - if (TREE_CODE (var) == PARM_DECL) - return false; - - /* Hard register variables get their initial value from the ether. */ - 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)); -} - /* Emit warnings for uninitialized variables. This is done in two passes. The first pass notices real uses of SSA names with undefined values. @@ -1310,7 +1620,7 @@ ssa_undefined_value_p (tree t) /* Emit a warning for T, an SSA_NAME, being uninitialized. The exact warning text is in MSGID and LOCUS may contain a location or be null. */ -static void +void warn_uninit (tree t, const char *gmsgid, void *data) { tree var = SSA_NAME_VAR (t); @@ -1329,7 +1639,7 @@ warn_uninit (tree t, const char *gmsgid, void *data) /* Do not warn if it can be initialized outside this module. */ if (is_global_var (var)) return; - + location = (context != NULL && gimple_has_location (context)) ? gimple_location (context) : DECL_SOURCE_LOCATION (var); @@ -1386,7 +1696,7 @@ warn_uninitialized_var (tree *tp, int *walk_subtrees, void *data_) use_operand_p vuse; tree op; - /* If there is not gimple stmt, + /* If there is not gimple stmt, or alias information has not been computed, then we cannot check VUSE ops. */ if (data->stmt == NULL) @@ -1401,7 +1711,7 @@ warn_uninitialized_var (tree *tp, int *walk_subtrees, void *data_) return NULL_TREE; op = USE_FROM_PTR (vuse); - if (t != SSA_NAME_VAR (op) + if (t != SSA_NAME_VAR (op) || !SSA_NAME_IS_DEFAULT_DEF (op)) return NULL_TREE; /* If this is a VUSE of t and it is the default definition, @@ -1440,28 +1750,7 @@ warn_uninitialized_var (tree *tp, int *walk_subtrees, void *data_) return NULL_TREE; } -/* Look for inputs to PHI that are SSA_NAMEs that have empty definitions - and warn about them. */ - -static void -warn_uninitialized_phi (gimple phi) -{ - size_t i, n = gimple_phi_num_args (phi); - - /* Don't look at memory tags. */ - if (!is_gimple_reg (gimple_phi_result (phi))) - return; - - for (i = 0; i < n; ++i) - { - tree op = gimple_phi_arg_def (phi, i); - if (TREE_CODE (op) == SSA_NAME) - warn_uninit (op, "%qD may be used uninitialized in this function", - NULL); - } -} - -static unsigned int +unsigned int warn_uninitialized_vars (bool warn_possibly_uninitialized) { gimple_stmt_iterator gsi; @@ -1470,7 +1759,6 @@ warn_uninitialized_vars (bool warn_possibly_uninitialized) data.warn_possibly_uninitialized = warn_possibly_uninitialized; - calculate_dominance_info (CDI_POST_DOMINATORS); FOR_EACH_BB (bb) { @@ -1480,16 +1768,14 @@ warn_uninitialized_vars (bool warn_possibly_uninitialized) { struct walk_stmt_info wi; data.stmt = gsi_stmt (gsi); + if (is_gimple_debug (data.stmt)) + continue; memset (&wi, 0, sizeof (wi)); wi.info = &data; walk_gimple_op (gsi_stmt (gsi), warn_uninitialized_var, &wi); } } - /* Post-dominator information can not be reliably updated. Free it - after the use. */ - - free_dominance_info (CDI_POST_DOMINATORS); return 0; } @@ -1502,25 +1788,14 @@ execute_early_warn_uninitialized (void) as possible, thus don't do it here. However, without optimization we need to warn here about "may be uninitialized". */ - warn_uninitialized_vars (/*warn_possibly_uninitialized=*/!optimize); - return 0; -} - -static unsigned int -execute_late_warn_uninitialized (void) -{ - basic_block bb; - gimple_stmt_iterator gsi; + calculate_dominance_info (CDI_POST_DOMINATORS); - /* Re-do the plain uninitialized variable check, as optimization may have - straightened control flow. Do this first so that we don't accidentally - get a "may be" warning when we'd have seen an "is" warning later. */ - warn_uninitialized_vars (/*warn_possibly_uninitialized=*/1); + warn_uninitialized_vars (/*warn_possibly_uninitialized=*/!optimize); - FOR_EACH_BB (bb) - for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) - warn_uninitialized_phi (gsi_stmt (gsi)); + /* Post-dominator information can not be reliably updated. Free it + after the use. */ + free_dominance_info (CDI_POST_DOMINATORS); return 0; } @@ -1534,7 +1809,7 @@ struct gimple_opt_pass pass_early_warn_uninitialized = { { GIMPLE_PASS, - NULL, /* name */ + "*early_warn_uninitialized", /* name */ gate_warn_uninitialized, /* gate */ execute_early_warn_uninitialized, /* execute */ NULL, /* sub */ @@ -1549,25 +1824,6 @@ struct gimple_opt_pass pass_early_warn_uninitialized = } }; -struct gimple_opt_pass pass_late_warn_uninitialized = -{ - { - GIMPLE_PASS, - NULL, /* name */ - gate_warn_uninitialized, /* gate */ - execute_late_warn_uninitialized, /* execute */ - NULL, /* sub */ - NULL, /* next */ - 0, /* static_pass_number */ - TV_NONE, /* tv_id */ - PROP_ssa, /* properties_required */ - 0, /* properties_provided */ - 0, /* properties_destroyed */ - 0, /* todo_flags_start */ - 0 /* todo_flags_finish */ - } -}; - /* Compute TREE_ADDRESSABLE and DECL_GIMPLE_REG_P for local variables. */ void @@ -1598,7 +1854,7 @@ execute_update_addresses_taken (bool do_optimize) if (code == GIMPLE_ASSIGN || code == GIMPLE_CALL) { tree lhs = gimple_get_lhs (stmt); - + /* We may not rewrite TMR_SYMBOL to SSA. */ if (lhs && TREE_CODE (lhs) == TARGET_MEM_REF && TMR_SYMBOL (lhs)) @@ -1687,7 +1943,8 @@ execute_update_addresses_taken (bool do_optimize) { gimple stmt = gsi_stmt (gsi); - if (gimple_references_memory_p (stmt)) + if (gimple_references_memory_p (stmt) + || is_gimple_debug (stmt)) update_stmt (stmt); }