812 lines
23 KiB
C
812 lines
23 KiB
C
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/* Tree lowering pass. Lowers GIMPLE into unstructured form.
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Copyright (C) 2003, 2005 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 2, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING. If not, write to the Free
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Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301, USA. */
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#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "tm.h"
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#include "tree.h"
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#include "rtl.h"
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#include "varray.h"
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#include "tree-gimple.h"
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#include "tree-inline.h"
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#include "diagnostic.h"
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#include "langhooks.h"
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#include "langhooks-def.h"
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#include "tree-flow.h"
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#include "timevar.h"
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#include "except.h"
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#include "hashtab.h"
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#include "flags.h"
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#include "function.h"
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#include "expr.h"
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#include "toplev.h"
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#include "tree-pass.h"
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struct lower_data
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{
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/* Block the current statement belongs to. */
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tree block;
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/* A TREE_LIST of label and return statements to be moved to the end
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of the function. */
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tree return_statements;
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/* True if the function calls __builtin_setjmp. */
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bool calls_builtin_setjmp;
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};
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static void lower_stmt (tree_stmt_iterator *, struct lower_data *);
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static void lower_bind_expr (tree_stmt_iterator *, struct lower_data *);
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static void lower_cond_expr (tree_stmt_iterator *, struct lower_data *);
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static void lower_return_expr (tree_stmt_iterator *, struct lower_data *);
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static void lower_builtin_setjmp (tree_stmt_iterator *);
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/* Lower the body of current_function_decl. */
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static unsigned int
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lower_function_body (void)
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{
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struct lower_data data;
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tree *body_p = &DECL_SAVED_TREE (current_function_decl);
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tree bind = *body_p;
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tree_stmt_iterator i;
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tree t, x;
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gcc_assert (TREE_CODE (bind) == BIND_EXPR);
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memset (&data, 0, sizeof (data));
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data.block = DECL_INITIAL (current_function_decl);
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BLOCK_SUBBLOCKS (data.block) = NULL_TREE;
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BLOCK_CHAIN (data.block) = NULL_TREE;
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TREE_ASM_WRITTEN (data.block) = 1;
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*body_p = alloc_stmt_list ();
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i = tsi_start (*body_p);
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tsi_link_after (&i, bind, TSI_NEW_STMT);
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lower_bind_expr (&i, &data);
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i = tsi_last (*body_p);
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/* If the function falls off the end, we need a null return statement.
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If we've already got one in the return_statements list, we don't
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need to do anything special. Otherwise build one by hand. */
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if (block_may_fallthru (*body_p)
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&& (data.return_statements == NULL
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|| TREE_OPERAND (TREE_VALUE (data.return_statements), 0) != NULL))
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{
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x = build1 (RETURN_EXPR, void_type_node, NULL);
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SET_EXPR_LOCATION (x, cfun->function_end_locus);
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tsi_link_after (&i, x, TSI_CONTINUE_LINKING);
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}
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/* If we lowered any return statements, emit the representative
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at the end of the function. */
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for (t = data.return_statements ; t ; t = TREE_CHAIN (t))
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{
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x = build1 (LABEL_EXPR, void_type_node, TREE_PURPOSE (t));
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tsi_link_after (&i, x, TSI_CONTINUE_LINKING);
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/* Remove the line number from the representative return statement.
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It now fills in for many such returns. Failure to remove this
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will result in incorrect results for coverage analysis. */
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x = TREE_VALUE (t);
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#ifdef USE_MAPPED_LOCATION
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SET_EXPR_LOCATION (x, UNKNOWN_LOCATION);
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#else
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SET_EXPR_LOCUS (x, NULL);
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#endif
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tsi_link_after (&i, x, TSI_CONTINUE_LINKING);
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}
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/* If the function calls __builtin_setjmp, we need to emit the computed
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goto that will serve as the unique dispatcher for all the receivers. */
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if (data.calls_builtin_setjmp)
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{
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tree disp_label, disp_var, arg;
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/* Build 'DISP_LABEL:' and insert. */
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disp_label = create_artificial_label ();
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/* This mark will create forward edges from every call site. */
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DECL_NONLOCAL (disp_label) = 1;
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current_function_has_nonlocal_label = 1;
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x = build1 (LABEL_EXPR, void_type_node, disp_label);
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tsi_link_after (&i, x, TSI_CONTINUE_LINKING);
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/* Build 'DISP_VAR = __builtin_setjmp_dispatcher (DISP_LABEL);'
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and insert. */
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disp_var = create_tmp_var (ptr_type_node, "setjmpvar");
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t = build_addr (disp_label, current_function_decl);
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arg = tree_cons (NULL, t, NULL);
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t = implicit_built_in_decls[BUILT_IN_SETJMP_DISPATCHER];
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t = build_function_call_expr (t,arg);
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x = build2 (MODIFY_EXPR, void_type_node, disp_var, t);
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/* Build 'goto DISP_VAR;' and insert. */
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tsi_link_after (&i, x, TSI_CONTINUE_LINKING);
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x = build1 (GOTO_EXPR, void_type_node, disp_var);
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tsi_link_after (&i, x, TSI_CONTINUE_LINKING);
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}
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gcc_assert (data.block == DECL_INITIAL (current_function_decl));
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BLOCK_SUBBLOCKS (data.block)
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= blocks_nreverse (BLOCK_SUBBLOCKS (data.block));
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clear_block_marks (data.block);
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return 0;
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}
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struct tree_opt_pass pass_lower_cf =
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{
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"lower", /* name */
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NULL, /* gate */
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lower_function_body, /* execute */
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NULL, /* sub */
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NULL, /* next */
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0, /* static_pass_number */
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0, /* tv_id */
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PROP_gimple_any, /* properties_required */
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PROP_gimple_lcf, /* properties_provided */
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0, /* properties_destroyed */
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0, /* todo_flags_start */
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TODO_dump_func, /* todo_flags_finish */
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0 /* letter */
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};
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/* Lower the EXPR. Unlike gimplification the statements are not relowered
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when they are changed -- if this has to be done, the lowering routine must
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do it explicitly. DATA is passed through the recursion. */
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static void
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lower_stmt_body (tree expr, struct lower_data *data)
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{
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tree_stmt_iterator tsi;
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for (tsi = tsi_start (expr); !tsi_end_p (tsi); )
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lower_stmt (&tsi, data);
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}
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/* Lower the OpenMP directive statement pointed by TSI. DATA is
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passed through the recursion. */
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static void
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lower_omp_directive (tree_stmt_iterator *tsi, struct lower_data *data)
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{
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tree stmt;
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stmt = tsi_stmt (*tsi);
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lower_stmt_body (OMP_BODY (stmt), data);
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tsi_link_before (tsi, stmt, TSI_SAME_STMT);
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tsi_link_before (tsi, OMP_BODY (stmt), TSI_SAME_STMT);
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OMP_BODY (stmt) = NULL_TREE;
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tsi_delink (tsi);
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}
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/* Lower statement TSI. DATA is passed through the recursion. */
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static void
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lower_stmt (tree_stmt_iterator *tsi, struct lower_data *data)
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{
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tree stmt = tsi_stmt (*tsi);
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if (EXPR_HAS_LOCATION (stmt) && data)
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TREE_BLOCK (stmt) = data->block;
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switch (TREE_CODE (stmt))
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{
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case BIND_EXPR:
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lower_bind_expr (tsi, data);
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return;
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case COND_EXPR:
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lower_cond_expr (tsi, data);
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return;
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case RETURN_EXPR:
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lower_return_expr (tsi, data);
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return;
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case TRY_FINALLY_EXPR:
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case TRY_CATCH_EXPR:
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lower_stmt_body (TREE_OPERAND (stmt, 0), data);
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lower_stmt_body (TREE_OPERAND (stmt, 1), data);
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break;
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case CATCH_EXPR:
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lower_stmt_body (CATCH_BODY (stmt), data);
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break;
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case EH_FILTER_EXPR:
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lower_stmt_body (EH_FILTER_FAILURE (stmt), data);
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break;
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case NOP_EXPR:
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case ASM_EXPR:
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case GOTO_EXPR:
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case LABEL_EXPR:
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case SWITCH_EXPR:
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case OMP_FOR:
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case OMP_SECTIONS:
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case OMP_SECTION:
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case OMP_SINGLE:
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case OMP_MASTER:
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case OMP_ORDERED:
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case OMP_CRITICAL:
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case OMP_RETURN:
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case OMP_CONTINUE:
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break;
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case MODIFY_EXPR:
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if (TREE_CODE (TREE_OPERAND (stmt, 1)) == CALL_EXPR)
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stmt = TREE_OPERAND (stmt, 1);
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else
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break;
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/* FALLTHRU */
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case CALL_EXPR:
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{
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tree decl = get_callee_fndecl (stmt);
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if (decl
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&& DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL
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&& DECL_FUNCTION_CODE (decl) == BUILT_IN_SETJMP)
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{
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data->calls_builtin_setjmp = true;
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lower_builtin_setjmp (tsi);
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return;
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}
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}
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break;
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case OMP_PARALLEL:
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lower_omp_directive (tsi, data);
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return;
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default:
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gcc_unreachable ();
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}
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tsi_next (tsi);
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}
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/* Lower a bind_expr TSI. DATA is passed through the recursion. */
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static void
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lower_bind_expr (tree_stmt_iterator *tsi, struct lower_data *data)
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{
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tree old_block = data->block;
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tree stmt = tsi_stmt (*tsi);
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tree new_block = BIND_EXPR_BLOCK (stmt);
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if (new_block)
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{
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if (new_block == old_block)
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{
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/* The outermost block of the original function may not be the
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outermost statement chain of the gimplified function. So we
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may see the outermost block just inside the function. */
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gcc_assert (new_block == DECL_INITIAL (current_function_decl));
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new_block = NULL;
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}
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else
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{
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/* We do not expect to handle duplicate blocks. */
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gcc_assert (!TREE_ASM_WRITTEN (new_block));
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TREE_ASM_WRITTEN (new_block) = 1;
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/* Block tree may get clobbered by inlining. Normally this would
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be fixed in rest_of_decl_compilation using block notes, but
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since we are not going to emit them, it is up to us. */
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BLOCK_CHAIN (new_block) = BLOCK_SUBBLOCKS (old_block);
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BLOCK_SUBBLOCKS (old_block) = new_block;
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BLOCK_SUBBLOCKS (new_block) = NULL_TREE;
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BLOCK_SUPERCONTEXT (new_block) = old_block;
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data->block = new_block;
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}
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}
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record_vars (BIND_EXPR_VARS (stmt));
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lower_stmt_body (BIND_EXPR_BODY (stmt), data);
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if (new_block)
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{
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gcc_assert (data->block == new_block);
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BLOCK_SUBBLOCKS (new_block)
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= blocks_nreverse (BLOCK_SUBBLOCKS (new_block));
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data->block = old_block;
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}
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/* The BIND_EXPR no longer carries any useful information -- kill it. */
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tsi_link_before (tsi, BIND_EXPR_BODY (stmt), TSI_SAME_STMT);
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tsi_delink (tsi);
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}
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/* Try to determine whether a TRY_CATCH expression can fall through.
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This is a subroutine of block_may_fallthru. */
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static bool
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try_catch_may_fallthru (tree stmt)
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{
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tree_stmt_iterator i;
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/* If the TRY block can fall through, the whole TRY_CATCH can
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fall through. */
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if (block_may_fallthru (TREE_OPERAND (stmt, 0)))
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return true;
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i = tsi_start (TREE_OPERAND (stmt, 1));
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switch (TREE_CODE (tsi_stmt (i)))
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{
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case CATCH_EXPR:
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/* We expect to see a sequence of CATCH_EXPR trees, each with a
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catch expression and a body. The whole TRY_CATCH may fall
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through iff any of the catch bodies falls through. */
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for (; !tsi_end_p (i); tsi_next (&i))
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{
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if (block_may_fallthru (CATCH_BODY (tsi_stmt (i))))
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return true;
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}
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return false;
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case EH_FILTER_EXPR:
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/* The exception filter expression only matters if there is an
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exception. If the exception does not match EH_FILTER_TYPES,
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we will execute EH_FILTER_FAILURE, and we will fall through
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if that falls through. If the exception does match
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EH_FILTER_TYPES, the stack unwinder will continue up the
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stack, so we will not fall through. We don't know whether we
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will throw an exception which matches EH_FILTER_TYPES or not,
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so we just ignore EH_FILTER_TYPES and assume that we might
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throw an exception which doesn't match. */
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return block_may_fallthru (EH_FILTER_FAILURE (tsi_stmt (i)));
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default:
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/* This case represents statements to be executed when an
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exception occurs. Those statements are implicitly followed
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by a RESX_EXPR to resume execution after the exception. So
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in this case the TRY_CATCH never falls through. */
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return false;
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}
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}
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/* Try to determine if we can fall out of the bottom of BLOCK. This guess
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need not be 100% accurate; simply be conservative and return true if we
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don't know. This is used only to avoid stupidly generating extra code.
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If we're wrong, we'll just delete the extra code later. */
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bool
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block_may_fallthru (tree block)
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{
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tree stmt = expr_last (block);
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switch (stmt ? TREE_CODE (stmt) : ERROR_MARK)
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|
{
|
|||
|
case GOTO_EXPR:
|
|||
|
case RETURN_EXPR:
|
|||
|
case RESX_EXPR:
|
|||
|
/* Easy cases. If the last statement of the block implies
|
|||
|
control transfer, then we can't fall through. */
|
|||
|
return false;
|
|||
|
|
|||
|
case SWITCH_EXPR:
|
|||
|
/* If SWITCH_LABELS is set, this is lowered, and represents a
|
|||
|
branch to a selected label and hence can not fall through.
|
|||
|
Otherwise SWITCH_BODY is set, and the switch can fall
|
|||
|
through. */
|
|||
|
return SWITCH_LABELS (stmt) == NULL_TREE;
|
|||
|
|
|||
|
case COND_EXPR:
|
|||
|
if (block_may_fallthru (COND_EXPR_THEN (stmt)))
|
|||
|
return true;
|
|||
|
return block_may_fallthru (COND_EXPR_ELSE (stmt));
|
|||
|
|
|||
|
case BIND_EXPR:
|
|||
|
return block_may_fallthru (BIND_EXPR_BODY (stmt));
|
|||
|
|
|||
|
case TRY_CATCH_EXPR:
|
|||
|
return try_catch_may_fallthru (stmt);
|
|||
|
|
|||
|
case TRY_FINALLY_EXPR:
|
|||
|
/* The finally clause is always executed after the try clause,
|
|||
|
so if it does not fall through, then the try-finally will not
|
|||
|
fall through. Otherwise, if the try clause does not fall
|
|||
|
through, then when the finally clause falls through it will
|
|||
|
resume execution wherever the try clause was going. So the
|
|||
|
whole try-finally will only fall through if both the try
|
|||
|
clause and the finally clause fall through. */
|
|||
|
return (block_may_fallthru (TREE_OPERAND (stmt, 0))
|
|||
|
&& block_may_fallthru (TREE_OPERAND (stmt, 1)));
|
|||
|
|
|||
|
case MODIFY_EXPR:
|
|||
|
if (TREE_CODE (TREE_OPERAND (stmt, 1)) == CALL_EXPR)
|
|||
|
stmt = TREE_OPERAND (stmt, 1);
|
|||
|
else
|
|||
|
return true;
|
|||
|
/* FALLTHRU */
|
|||
|
|
|||
|
case CALL_EXPR:
|
|||
|
/* Functions that do not return do not fall through. */
|
|||
|
return (call_expr_flags (stmt) & ECF_NORETURN) == 0;
|
|||
|
|
|||
|
case CLEANUP_POINT_EXPR:
|
|||
|
return block_may_fallthru (TREE_OPERAND (stmt, 0));
|
|||
|
|
|||
|
default:
|
|||
|
return true;
|
|||
|
}
|
|||
|
}
|
|||
|
|
|||
|
/* Lower a cond_expr TSI. DATA is passed through the recursion. */
|
|||
|
|
|||
|
static void
|
|||
|
lower_cond_expr (tree_stmt_iterator *tsi, struct lower_data *data)
|
|||
|
{
|
|||
|
tree stmt = tsi_stmt (*tsi);
|
|||
|
bool then_is_goto, else_is_goto;
|
|||
|
tree then_branch, else_branch;
|
|||
|
tree then_goto, else_goto;
|
|||
|
|
|||
|
then_branch = COND_EXPR_THEN (stmt);
|
|||
|
else_branch = COND_EXPR_ELSE (stmt);
|
|||
|
|
|||
|
lower_stmt_body (then_branch, data);
|
|||
|
lower_stmt_body (else_branch, data);
|
|||
|
|
|||
|
then_goto = expr_only (then_branch);
|
|||
|
then_is_goto = then_goto && simple_goto_p (then_goto);
|
|||
|
|
|||
|
else_goto = expr_only (else_branch);
|
|||
|
else_is_goto = else_goto && simple_goto_p (else_goto);
|
|||
|
|
|||
|
if (!then_is_goto || !else_is_goto)
|
|||
|
{
|
|||
|
tree then_label, else_label, end_label, t;
|
|||
|
|
|||
|
then_label = NULL_TREE;
|
|||
|
else_label = NULL_TREE;
|
|||
|
end_label = NULL_TREE;
|
|||
|
|
|||
|
/* Replace the cond_expr with explicit gotos. */
|
|||
|
if (!then_is_goto)
|
|||
|
{
|
|||
|
t = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
|
|||
|
if (TREE_SIDE_EFFECTS (then_branch))
|
|||
|
then_label = t;
|
|||
|
else
|
|||
|
end_label = t;
|
|||
|
then_goto = build_and_jump (&LABEL_EXPR_LABEL (t));
|
|||
|
}
|
|||
|
|
|||
|
if (!else_is_goto)
|
|||
|
{
|
|||
|
t = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
|
|||
|
if (TREE_SIDE_EFFECTS (else_branch))
|
|||
|
else_label = t;
|
|||
|
else
|
|||
|
{
|
|||
|
/* Both THEN and ELSE can be no-ops if one or both contained an
|
|||
|
empty BIND_EXPR that was associated with the toplevel block
|
|||
|
of an inlined function. In that case remove_useless_stmts
|
|||
|
can't have cleaned things up for us; kill the whole
|
|||
|
conditional now. */
|
|||
|
if (end_label)
|
|||
|
{
|
|||
|
tsi_delink (tsi);
|
|||
|
return;
|
|||
|
}
|
|||
|
else
|
|||
|
end_label = t;
|
|||
|
}
|
|||
|
else_goto = build_and_jump (&LABEL_EXPR_LABEL (t));
|
|||
|
}
|
|||
|
|
|||
|
if (then_label)
|
|||
|
{
|
|||
|
bool may_fallthru = block_may_fallthru (then_branch);
|
|||
|
|
|||
|
tsi_link_after (tsi, then_label, TSI_CONTINUE_LINKING);
|
|||
|
tsi_link_after (tsi, then_branch, TSI_CONTINUE_LINKING);
|
|||
|
|
|||
|
if (else_label && may_fallthru)
|
|||
|
{
|
|||
|
end_label = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
|
|||
|
t = build_and_jump (&LABEL_EXPR_LABEL (end_label));
|
|||
|
tsi_link_after (tsi, t, TSI_CONTINUE_LINKING);
|
|||
|
}
|
|||
|
}
|
|||
|
|
|||
|
if (else_label)
|
|||
|
{
|
|||
|
tsi_link_after (tsi, else_label, TSI_CONTINUE_LINKING);
|
|||
|
tsi_link_after (tsi, else_branch, TSI_CONTINUE_LINKING);
|
|||
|
}
|
|||
|
|
|||
|
if (end_label)
|
|||
|
tsi_link_after (tsi, end_label, TSI_CONTINUE_LINKING);
|
|||
|
}
|
|||
|
|
|||
|
COND_EXPR_THEN (stmt) = then_goto;
|
|||
|
COND_EXPR_ELSE (stmt) = else_goto;
|
|||
|
|
|||
|
tsi_next (tsi);
|
|||
|
}
|
|||
|
|
|||
|
/* Lower a return_expr TSI. DATA is passed through the recursion. */
|
|||
|
|
|||
|
static void
|
|||
|
lower_return_expr (tree_stmt_iterator *tsi, struct lower_data *data)
|
|||
|
{
|
|||
|
tree stmt = tsi_stmt (*tsi);
|
|||
|
tree value, t, label;
|
|||
|
|
|||
|
/* Extract the value being returned. */
|
|||
|
value = TREE_OPERAND (stmt, 0);
|
|||
|
if (value && TREE_CODE (value) == MODIFY_EXPR)
|
|||
|
value = TREE_OPERAND (value, 1);
|
|||
|
|
|||
|
/* Match this up with an existing return statement that's been created. */
|
|||
|
for (t = data->return_statements; t ; t = TREE_CHAIN (t))
|
|||
|
{
|
|||
|
tree tvalue = TREE_OPERAND (TREE_VALUE (t), 0);
|
|||
|
if (tvalue && TREE_CODE (tvalue) == MODIFY_EXPR)
|
|||
|
tvalue = TREE_OPERAND (tvalue, 1);
|
|||
|
|
|||
|
if (value == tvalue)
|
|||
|
{
|
|||
|
label = TREE_PURPOSE (t);
|
|||
|
goto found;
|
|||
|
}
|
|||
|
}
|
|||
|
|
|||
|
/* Not found. Create a new label and record the return statement. */
|
|||
|
label = create_artificial_label ();
|
|||
|
data->return_statements = tree_cons (label, stmt, data->return_statements);
|
|||
|
|
|||
|
/* Generate a goto statement and remove the return statement. */
|
|||
|
found:
|
|||
|
t = build1 (GOTO_EXPR, void_type_node, label);
|
|||
|
SET_EXPR_LOCUS (t, EXPR_LOCUS (stmt));
|
|||
|
tsi_link_before (tsi, t, TSI_SAME_STMT);
|
|||
|
tsi_delink (tsi);
|
|||
|
}
|
|||
|
|
|||
|
/* Lower a __builtin_setjmp TSI.
|
|||
|
|
|||
|
__builtin_setjmp is passed a pointer to an array of five words (not
|
|||
|
all will be used on all machines). It operates similarly to the C
|
|||
|
library function of the same name, but is more efficient.
|
|||
|
|
|||
|
It is lowered into 3 other builtins, namely __builtin_setjmp_setup,
|
|||
|
__builtin_setjmp_dispatcher and __builtin_setjmp_receiver, but with
|
|||
|
__builtin_setjmp_dispatcher shared among all the instances; that's
|
|||
|
why it is only emitted at the end by lower_function_body.
|
|||
|
|
|||
|
After full lowering, the body of the function should look like:
|
|||
|
|
|||
|
{
|
|||
|
void * setjmpvar.0;
|
|||
|
int D.1844;
|
|||
|
int D.2844;
|
|||
|
|
|||
|
[...]
|
|||
|
|
|||
|
__builtin_setjmp_setup (&buf, &<D1847>);
|
|||
|
D.1844 = 0;
|
|||
|
goto <D1846>;
|
|||
|
<D1847>:;
|
|||
|
__builtin_setjmp_receiver (&<D1847>);
|
|||
|
D.1844 = 1;
|
|||
|
<D1846>:;
|
|||
|
if (D.1844 == 0) goto <D1848>; else goto <D1849>;
|
|||
|
|
|||
|
[...]
|
|||
|
|
|||
|
__builtin_setjmp_setup (&buf, &<D2847>);
|
|||
|
D.2844 = 0;
|
|||
|
goto <D2846>;
|
|||
|
<D2847>:;
|
|||
|
__builtin_setjmp_receiver (&<D2847>);
|
|||
|
D.2844 = 1;
|
|||
|
<D2846>:;
|
|||
|
if (D.2844 == 0) goto <D2848>; else goto <D2849>;
|
|||
|
|
|||
|
[...]
|
|||
|
|
|||
|
<D3850>:;
|
|||
|
return;
|
|||
|
<D3853>: [non-local];
|
|||
|
setjmpvar.0 = __builtin_setjmp_dispatcher (&<D3853>);
|
|||
|
goto setjmpvar.0;
|
|||
|
}
|
|||
|
|
|||
|
The dispatcher block will be both the unique destination of all the
|
|||
|
abnormal call edges and the unique source of all the abnormal edges
|
|||
|
to the receivers, thus keeping the complexity explosion localized. */
|
|||
|
|
|||
|
static void
|
|||
|
lower_builtin_setjmp (tree_stmt_iterator *tsi)
|
|||
|
{
|
|||
|
tree stmt = tsi_stmt (*tsi);
|
|||
|
tree cont_label = create_artificial_label ();
|
|||
|
tree next_label = create_artificial_label ();
|
|||
|
tree dest, t, arg;
|
|||
|
|
|||
|
/* NEXT_LABEL is the label __builtin_longjmp will jump to. Its address is
|
|||
|
passed to both __builtin_setjmp_setup and __builtin_setjmp_receiver. */
|
|||
|
FORCED_LABEL (next_label) = 1;
|
|||
|
|
|||
|
if (TREE_CODE (stmt) == MODIFY_EXPR)
|
|||
|
{
|
|||
|
dest = TREE_OPERAND (stmt, 0);
|
|||
|
stmt = TREE_OPERAND (stmt, 1);
|
|||
|
}
|
|||
|
else
|
|||
|
dest = NULL_TREE;
|
|||
|
|
|||
|
/* Build '__builtin_setjmp_setup (BUF, NEXT_LABEL)' and insert. */
|
|||
|
t = build_addr (next_label, current_function_decl);
|
|||
|
arg = tree_cons (NULL, t, NULL);
|
|||
|
t = TREE_VALUE (TREE_OPERAND (stmt, 1));
|
|||
|
arg = tree_cons (NULL, t, arg);
|
|||
|
t = implicit_built_in_decls[BUILT_IN_SETJMP_SETUP];
|
|||
|
t = build_function_call_expr (t, arg);
|
|||
|
SET_EXPR_LOCUS (t, EXPR_LOCUS (stmt));
|
|||
|
tsi_link_before (tsi, t, TSI_SAME_STMT);
|
|||
|
|
|||
|
/* Build 'DEST = 0' and insert. */
|
|||
|
if (dest)
|
|||
|
{
|
|||
|
t = build2 (MODIFY_EXPR, void_type_node, dest, integer_zero_node);
|
|||
|
SET_EXPR_LOCUS (t, EXPR_LOCUS (stmt));
|
|||
|
tsi_link_before (tsi, t, TSI_SAME_STMT);
|
|||
|
}
|
|||
|
|
|||
|
/* Build 'goto CONT_LABEL' and insert. */
|
|||
|
t = build1 (GOTO_EXPR, void_type_node, cont_label);
|
|||
|
tsi_link_before (tsi, t, TSI_SAME_STMT);
|
|||
|
|
|||
|
/* Build 'NEXT_LABEL:' and insert. */
|
|||
|
t = build1 (LABEL_EXPR, void_type_node, next_label);
|
|||
|
tsi_link_before (tsi, t, TSI_SAME_STMT);
|
|||
|
|
|||
|
/* Build '__builtin_setjmp_receiver (NEXT_LABEL)' and insert. */
|
|||
|
t = build_addr (next_label, current_function_decl);
|
|||
|
arg = tree_cons (NULL, t, NULL);
|
|||
|
t = implicit_built_in_decls[BUILT_IN_SETJMP_RECEIVER];
|
|||
|
t = build_function_call_expr (t, arg);
|
|||
|
SET_EXPR_LOCUS (t, EXPR_LOCUS (stmt));
|
|||
|
tsi_link_before (tsi, t, TSI_SAME_STMT);
|
|||
|
|
|||
|
/* Build 'DEST = 1' and insert. */
|
|||
|
if (dest)
|
|||
|
{
|
|||
|
t = build2 (MODIFY_EXPR, void_type_node, dest, integer_one_node);
|
|||
|
SET_EXPR_LOCUS (t, EXPR_LOCUS (stmt));
|
|||
|
tsi_link_before (tsi, t, TSI_SAME_STMT);
|
|||
|
}
|
|||
|
|
|||
|
/* Build 'CONT_LABEL:' and insert. */
|
|||
|
t = build1 (LABEL_EXPR, void_type_node, cont_label);
|
|||
|
tsi_link_before (tsi, t, TSI_SAME_STMT);
|
|||
|
|
|||
|
/* Remove the call to __builtin_setjmp. */
|
|||
|
tsi_delink (tsi);
|
|||
|
}
|
|||
|
|
|||
|
|
|||
|
/* Record the variables in VARS into function FN. */
|
|||
|
|
|||
|
void
|
|||
|
record_vars_into (tree vars, tree fn)
|
|||
|
{
|
|||
|
struct function *saved_cfun = cfun;
|
|||
|
|
|||
|
if (fn != current_function_decl)
|
|||
|
cfun = DECL_STRUCT_FUNCTION (fn);
|
|||
|
|
|||
|
for (; vars; vars = TREE_CHAIN (vars))
|
|||
|
{
|
|||
|
tree var = vars;
|
|||
|
|
|||
|
/* BIND_EXPRs contains also function/type/constant declarations
|
|||
|
we don't need to care about. */
|
|||
|
if (TREE_CODE (var) != VAR_DECL)
|
|||
|
continue;
|
|||
|
|
|||
|
/* Nothing to do in this case. */
|
|||
|
if (DECL_EXTERNAL (var))
|
|||
|
continue;
|
|||
|
|
|||
|
/* Record the variable. */
|
|||
|
cfun->unexpanded_var_list = tree_cons (NULL_TREE, var,
|
|||
|
cfun->unexpanded_var_list);
|
|||
|
}
|
|||
|
|
|||
|
if (fn != current_function_decl)
|
|||
|
cfun = saved_cfun;
|
|||
|
}
|
|||
|
|
|||
|
|
|||
|
/* Record the variables in VARS into current_function_decl. */
|
|||
|
|
|||
|
void
|
|||
|
record_vars (tree vars)
|
|||
|
{
|
|||
|
record_vars_into (vars, current_function_decl);
|
|||
|
}
|
|||
|
|
|||
|
|
|||
|
/* Mark BLOCK used if it has a used variable in it, then recurse over its
|
|||
|
subblocks. */
|
|||
|
|
|||
|
static void
|
|||
|
mark_blocks_with_used_vars (tree block)
|
|||
|
{
|
|||
|
tree var;
|
|||
|
tree subblock;
|
|||
|
|
|||
|
if (!TREE_USED (block))
|
|||
|
{
|
|||
|
for (var = BLOCK_VARS (block);
|
|||
|
var;
|
|||
|
var = TREE_CHAIN (var))
|
|||
|
{
|
|||
|
if (TREE_USED (var))
|
|||
|
{
|
|||
|
TREE_USED (block) = true;
|
|||
|
break;
|
|||
|
}
|
|||
|
}
|
|||
|
}
|
|||
|
for (subblock = BLOCK_SUBBLOCKS (block);
|
|||
|
subblock;
|
|||
|
subblock = BLOCK_CHAIN (subblock))
|
|||
|
mark_blocks_with_used_vars (subblock);
|
|||
|
}
|
|||
|
|
|||
|
/* Mark the used attribute on blocks correctly. */
|
|||
|
|
|||
|
static unsigned int
|
|||
|
mark_used_blocks (void)
|
|||
|
{
|
|||
|
mark_blocks_with_used_vars (DECL_INITIAL (current_function_decl));
|
|||
|
return 0;
|
|||
|
}
|
|||
|
|
|||
|
|
|||
|
struct tree_opt_pass pass_mark_used_blocks =
|
|||
|
{
|
|||
|
"blocks", /* name */
|
|||
|
NULL, /* gate */
|
|||
|
mark_used_blocks, /* execute */
|
|||
|
NULL, /* sub */
|
|||
|
NULL, /* next */
|
|||
|
0, /* static_pass_number */
|
|||
|
0, /* tv_id */
|
|||
|
0, /* properties_required */
|
|||
|
0, /* properties_provided */
|
|||
|
0, /* properties_destroyed */
|
|||
|
0, /* todo_flags_start */
|
|||
|
TODO_dump_func, /* todo_flags_finish */
|
|||
|
0 /* letter */
|
|||
|
};
|