/* Tree lowering pass. Lowers GIMPLE into unstructured form.
- Copyright (C) 2003 Free Software Foundation, Inc.
+ Copyright (C) 2003, 2004, 2005, 2006, 2007 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 2, or (at your option) any later
+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
for more details.
You should have received a copy of the GNU General Public License
-along with GCC; see the file COPYING. If not, write to the Free
-Software Foundation, 59 Temple Place - Suite 330, Boston, MA
-02111-1307, USA. */
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
#include "tm.h"
#include "tree.h"
#include "rtl.h"
-#include "errors.h"
#include "varray.h"
#include "tree-gimple.h"
#include "tree-inline.h"
/* A TREE_LIST of label and return statements to be moved to the end
of the function. */
tree return_statements;
+
+ /* True if the function calls __builtin_setjmp. */
+ bool calls_builtin_setjmp;
};
static void lower_stmt (tree_stmt_iterator *, struct lower_data *);
static void lower_bind_expr (tree_stmt_iterator *, struct lower_data *);
static void lower_cond_expr (tree_stmt_iterator *, struct lower_data *);
static void lower_return_expr (tree_stmt_iterator *, struct lower_data *);
-static bool expand_var_p (tree);
+static void lower_builtin_setjmp (tree_stmt_iterator *);
-/* Lowers the body of current_function_decl. */
+/* Lower the body of current_function_decl. */
-static void
+static unsigned int
lower_function_body (void)
{
struct lower_data data;
gcc_assert (TREE_CODE (bind) == BIND_EXPR);
+ memset (&data, 0, sizeof (data));
data.block = DECL_INITIAL (current_function_decl);
BLOCK_SUBBLOCKS (data.block) = NULL_TREE;
BLOCK_CHAIN (data.block) = NULL_TREE;
TREE_ASM_WRITTEN (data.block) = 1;
- data.return_statements = NULL_TREE;
-
*body_p = alloc_stmt_list ();
i = tsi_start (*body_p);
tsi_link_after (&i, bind, TSI_NEW_STMT);
&& (data.return_statements == NULL
|| TREE_OPERAND (TREE_VALUE (data.return_statements), 0) != NULL))
{
- x = build (RETURN_EXPR, void_type_node, NULL);
+ x = build1 (RETURN_EXPR, void_type_node, NULL);
SET_EXPR_LOCATION (x, cfun->function_end_locus);
tsi_link_after (&i, x, TSI_CONTINUE_LINKING);
}
at the end of the function. */
for (t = data.return_statements ; t ; t = TREE_CHAIN (t))
{
- x = build (LABEL_EXPR, void_type_node, TREE_PURPOSE (t));
+ x = build1 (LABEL_EXPR, void_type_node, TREE_PURPOSE (t));
tsi_link_after (&i, x, TSI_CONTINUE_LINKING);
/* Remove the line number from the representative return statement.
tsi_link_after (&i, x, TSI_CONTINUE_LINKING);
}
+ /* If the function calls __builtin_setjmp, we need to emit the computed
+ goto that will serve as the unique dispatcher for all the receivers. */
+ if (data.calls_builtin_setjmp)
+ {
+ tree disp_label, disp_var, arg;
+
+ /* Build 'DISP_LABEL:' and insert. */
+ disp_label = create_artificial_label ();
+ /* This mark will create forward edges from every call site. */
+ DECL_NONLOCAL (disp_label) = 1;
+ current_function_has_nonlocal_label = 1;
+ x = build1 (LABEL_EXPR, void_type_node, disp_label);
+ tsi_link_after (&i, x, TSI_CONTINUE_LINKING);
+
+ /* Build 'DISP_VAR = __builtin_setjmp_dispatcher (DISP_LABEL);'
+ and insert. */
+ disp_var = create_tmp_var (ptr_type_node, "setjmpvar");
+ arg = build_addr (disp_label, current_function_decl);
+ t = implicit_built_in_decls[BUILT_IN_SETJMP_DISPATCHER];
+ t = build_call_expr (t, 1, arg);
+ x = build_gimple_modify_stmt (disp_var, t);
+
+ /* Build 'goto DISP_VAR;' and insert. */
+ tsi_link_after (&i, x, TSI_CONTINUE_LINKING);
+ x = build1 (GOTO_EXPR, void_type_node, disp_var);
+ tsi_link_after (&i, x, TSI_CONTINUE_LINKING);
+ }
+
gcc_assert (data.block == DECL_INITIAL (current_function_decl));
BLOCK_SUBBLOCKS (data.block)
= blocks_nreverse (BLOCK_SUBBLOCKS (data.block));
clear_block_marks (data.block);
+ return 0;
}
struct tree_opt_pass pass_lower_cf =
0, /* tv_id */
PROP_gimple_any, /* properties_required */
PROP_gimple_lcf, /* properties_provided */
- PROP_gimple_any, /* properties_destroyed */
+ 0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func, /* todo_flags_finish */
0 /* letter */
};
-/* Lowers the EXPR. Unlike gimplification the statements are not relowered
+/* Lower the EXPR. Unlike gimplification the statements are not relowered
when they are changed -- if this has to be done, the lowering routine must
do it explicitly. DATA is passed through the recursion. */
-void
+static void
lower_stmt_body (tree expr, struct lower_data *data)
{
tree_stmt_iterator tsi;
lower_stmt (&tsi, data);
}
-/* Lowers statement TSI. DATA is passed through the recursion. */
+
+/* Lower the OpenMP directive statement pointed by TSI. DATA is
+ passed through the recursion. */
+
+static void
+lower_omp_directive (tree_stmt_iterator *tsi, struct lower_data *data)
+{
+ tree stmt;
+
+ stmt = tsi_stmt (*tsi);
+
+ lower_stmt_body (OMP_BODY (stmt), data);
+ tsi_link_before (tsi, stmt, TSI_SAME_STMT);
+ tsi_link_before (tsi, OMP_BODY (stmt), TSI_SAME_STMT);
+ OMP_BODY (stmt) = NULL_TREE;
+ tsi_delink (tsi);
+}
+
+
+/* Lower statement TSI. DATA is passed through the recursion. */
static void
lower_stmt (tree_stmt_iterator *tsi, struct lower_data *data)
case NOP_EXPR:
case ASM_EXPR:
- case MODIFY_EXPR:
- case CALL_EXPR:
case GOTO_EXPR:
case LABEL_EXPR:
case SWITCH_EXPR:
+ case CHANGE_DYNAMIC_TYPE_EXPR:
+ case OMP_FOR:
+ case OMP_SECTIONS:
+ case OMP_SECTIONS_SWITCH:
+ case OMP_SECTION:
+ case OMP_SINGLE:
+ case OMP_MASTER:
+ case OMP_ORDERED:
+ case OMP_CRITICAL:
+ case OMP_RETURN:
+ case OMP_CONTINUE:
break;
+ case GIMPLE_MODIFY_STMT:
+ if (TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1)) == CALL_EXPR)
+ stmt = GIMPLE_STMT_OPERAND (stmt, 1);
+ else
+ break;
+ /* FALLTHRU */
+
+ case CALL_EXPR:
+ {
+ tree decl = get_callee_fndecl (stmt);
+ if (decl
+ && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL
+ && DECL_FUNCTION_CODE (decl) == BUILT_IN_SETJMP)
+ {
+ data->calls_builtin_setjmp = true;
+ lower_builtin_setjmp (tsi);
+ return;
+ }
+ }
+ break;
+
+ case OMP_PARALLEL:
+ lower_omp_directive (tsi, data);
+ return;
+
default:
-#ifdef ENABLE_CHECKING
- print_node_brief (stderr, "", stmt, 0);
- internal_error ("unexpected node");
-#endif
- case COMPOUND_EXPR:
gcc_unreachable ();
}
tsi_next (tsi);
}
-/* Lowers a bind_expr TSI. DATA is passed through the recursion. */
+/* Lower a bind_expr TSI. DATA is passed through the recursion. */
static void
lower_bind_expr (tree_stmt_iterator *tsi, struct lower_data *data)
tsi_delink (tsi);
}
+/* Try to determine whether a TRY_CATCH expression can fall through.
+ This is a subroutine of block_may_fallthru. */
+
+static bool
+try_catch_may_fallthru (const_tree stmt)
+{
+ tree_stmt_iterator i;
+
+ /* If the TRY block can fall through, the whole TRY_CATCH can
+ fall through. */
+ if (block_may_fallthru (TREE_OPERAND (stmt, 0)))
+ return true;
+
+ i = tsi_start (TREE_OPERAND (stmt, 1));
+ switch (TREE_CODE (tsi_stmt (i)))
+ {
+ case CATCH_EXPR:
+ /* We expect to see a sequence of CATCH_EXPR trees, each with a
+ catch expression and a body. The whole TRY_CATCH may fall
+ through iff any of the catch bodies falls through. */
+ for (; !tsi_end_p (i); tsi_next (&i))
+ {
+ if (block_may_fallthru (CATCH_BODY (tsi_stmt (i))))
+ return true;
+ }
+ return false;
+
+ case EH_FILTER_EXPR:
+ /* The exception filter expression only matters if there is an
+ exception. If the exception does not match EH_FILTER_TYPES,
+ we will execute EH_FILTER_FAILURE, and we will fall through
+ if that falls through. If the exception does match
+ EH_FILTER_TYPES, the stack unwinder will continue up the
+ stack, so we will not fall through. We don't know whether we
+ will throw an exception which matches EH_FILTER_TYPES or not,
+ so we just ignore EH_FILTER_TYPES and assume that we might
+ throw an exception which doesn't match. */
+ return block_may_fallthru (EH_FILTER_FAILURE (tsi_stmt (i)));
+
+ default:
+ /* This case represents statements to be executed when an
+ exception occurs. Those statements are implicitly followed
+ by a RESX_EXPR to resume execution after the exception. So
+ in this case the TRY_CATCH never falls through. */
+ return false;
+ }
+}
+
/* Try to determine if we can fall out of the bottom of BLOCK. This guess
need not be 100% accurate; simply be conservative and return true if we
don't know. This is used only to avoid stupidly generating extra code.
If we're wrong, we'll just delete the extra code later. */
bool
-block_may_fallthru (tree block)
+block_may_fallthru (const_tree block)
{
- tree stmt = expr_last (block);
+ /* This CONST_CAST is okay because expr_last returns it's argument
+ unmodified and we assign it to a const_tree. */
+ const_tree stmt = expr_last (CONST_CAST_TREE(block));
switch (stmt ? TREE_CODE (stmt) : ERROR_MARK)
{
case GOTO_EXPR:
case RETURN_EXPR:
case RESX_EXPR:
- case SWITCH_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;
case BIND_EXPR:
return block_may_fallthru (BIND_EXPR_BODY (stmt));
- case TRY_FINALLY_EXPR:
- return block_may_fallthru (TREE_OPERAND (stmt, 1));
+ case TRY_CATCH_EXPR:
+ return try_catch_may_fallthru (stmt);
- case MODIFY_EXPR:
- if (TREE_CODE (TREE_OPERAND (stmt, 1)) == CALL_EXPR)
- stmt = TREE_OPERAND (stmt, 1);
+ 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 GIMPLE_MODIFY_STMT:
+ if (TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1)) == CALL_EXPR)
+ stmt = GIMPLE_STMT_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;
}
}
-/* Lowers a cond_expr TSI. DATA is passed through the recursion. */
+/* Lower a cond_expr TSI. DATA is passed through the recursion. */
static void
lower_cond_expr (tree_stmt_iterator *tsi, struct lower_data *data)
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)
{
/* Extract the value being returned. */
value = TREE_OPERAND (stmt, 0);
- if (value && TREE_CODE (value) == MODIFY_EXPR)
- value = TREE_OPERAND (value, 1);
+ if (value && TREE_CODE (value) == GIMPLE_MODIFY_STMT)
+ value = GIMPLE_STMT_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 (tvalue && TREE_CODE (tvalue) == GIMPLE_MODIFY_STMT)
+ tvalue = GIMPLE_STMT_OPERAND (tvalue, 1);
if (value == tvalue)
{
/* Generate a goto statement and remove the return statement. */
found:
- t = build (GOTO_EXPR, void_type_node, label);
+ 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);
}
-\f
-/* Record the variables in VARS. */
+/* Lower a __builtin_setjmp TSI.
-void
-record_vars (tree vars)
-{
- for (; vars; vars = TREE_CHAIN (vars))
- {
- tree var = vars;
+ __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.
- /* Nothing to do in this case. */
- if (DECL_EXTERNAL (var))
- continue;
- if (TREE_CODE (var) == FUNCTION_DECL)
- continue;
+ 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.
- /* Record the variable. */
- cfun->unexpanded_var_list = tree_cons (NULL_TREE, var,
- cfun->unexpanded_var_list);
+ 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;
}
-}
-/* Check whether to expand a variable VAR. */
+ 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 bool
-expand_var_p (tree var)
+static void
+lower_builtin_setjmp (tree_stmt_iterator *tsi)
{
- struct var_ann_d *ann;
+ tree stmt = tsi_stmt (*tsi);
+ tree cont_label = create_artificial_label ();
+ tree next_label = create_artificial_label ();
+ tree dest, t, arg;
- if (TREE_CODE (var) != VAR_DECL)
- return true;
+ /* 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;
- /* Leave statics and externals alone. */
- if (TREE_STATIC (var) || DECL_EXTERNAL (var))
- return true;
+ if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT)
+ {
+ dest = GIMPLE_STMT_OPERAND (stmt, 0);
+ stmt = GIMPLE_STMT_OPERAND (stmt, 1);
+ }
+ else
+ dest = NULL_TREE;
- /* Remove all unused local variables. */
- ann = var_ann (var);
- if (!ann || !ann->used)
- return false;
+ /* Build '__builtin_setjmp_setup (BUF, NEXT_LABEL)' and insert. */
+ arg = build_addr (next_label, current_function_decl);
+ t = implicit_built_in_decls[BUILT_IN_SETJMP_SETUP];
+ t = build_call_expr (t, 2, CALL_EXPR_ARG (stmt, 0), arg);
+ SET_EXPR_LOCUS (t, EXPR_LOCUS (stmt));
+ tsi_link_before (tsi, t, TSI_SAME_STMT);
- return true;
-}
+ /* Build 'DEST = 0' and insert. */
+ if (dest)
+ {
+ t = build_gimple_modify_stmt (dest, fold_convert (TREE_TYPE (dest),
+ integer_zero_node));
+ SET_EXPR_LOCUS (t, EXPR_LOCUS (stmt));
+ tsi_link_before (tsi, t, TSI_SAME_STMT);
+ }
-/* Throw away variables that are unused. */
+ /* Build 'goto CONT_LABEL' and insert. */
+ t = build1 (GOTO_EXPR, void_type_node, cont_label);
+ tsi_link_before (tsi, t, TSI_SAME_STMT);
-static void
-remove_useless_vars (void)
-{
- tree var, *cell;
- FILE *df = NULL;
+ /* Build 'NEXT_LABEL:' and insert. */
+ t = build1 (LABEL_EXPR, void_type_node, next_label);
+ tsi_link_before (tsi, t, TSI_SAME_STMT);
- if (dump_file && (dump_flags & TDF_DETAILS))
+ /* Build '__builtin_setjmp_receiver (NEXT_LABEL)' and insert. */
+ arg = build_addr (next_label, current_function_decl);
+ t = implicit_built_in_decls[BUILT_IN_SETJMP_RECEIVER];
+ t = build_call_expr (t, 1, arg);
+ SET_EXPR_LOCUS (t, EXPR_LOCUS (stmt));
+ tsi_link_before (tsi, t, TSI_SAME_STMT);
+
+ /* Build 'DEST = 1' and insert. */
+ if (dest)
{
- df = dump_file;
- fputs ("Discarding as unused:\n", df);
+ t = build_gimple_modify_stmt (dest, fold_convert (TREE_TYPE (dest),
+ integer_one_node));
+ SET_EXPR_LOCUS (t, EXPR_LOCUS (stmt));
+ tsi_link_before (tsi, t, TSI_SAME_STMT);
}
- for (cell = &cfun->unexpanded_var_list; *cell; )
+ /* 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);
+}
+\f
+
+/* Record the variables in VARS into function FN. */
+
+void
+record_vars_into (tree vars, tree fn)
+{
+ if (fn != current_function_decl)
+ push_cfun (DECL_STRUCT_FUNCTION (fn));
+
+ for (; vars; vars = TREE_CHAIN (vars))
{
- var = TREE_VALUE (*cell);
+ tree var = vars;
- if (!expand_var_p (var))
- {
- if (df)
- {
- fputs (" ", df);
- print_generic_expr (df, var, dump_flags);
- fputc ('\n', df);
- }
+ /* BIND_EXPRs contains also function/type/constant declarations
+ we don't need to care about. */
+ if (TREE_CODE (var) != VAR_DECL)
+ continue;
- *cell = TREE_CHAIN (*cell);
- continue;
- }
+ /* Nothing to do in this case. */
+ if (DECL_EXTERNAL (var))
+ continue;
- cell = &TREE_CHAIN (*cell);
+ /* Record the variable. */
+ cfun->unexpanded_var_list = tree_cons (NULL_TREE, var,
+ cfun->unexpanded_var_list);
}
- if (df)
- fputc ('\n', df);
+ if (fn != current_function_decl)
+ pop_cfun ();
}
-struct tree_opt_pass pass_remove_useless_vars =
+
+/* Record the variables in VARS into current_function_decl. */
+
+void
+record_vars (tree vars)
{
- "vars", /* name */
- NULL, /* gate */
- remove_useless_vars, /* 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 */
-};
+ record_vars_into (vars, current_function_decl);
+}
+
/* Mark BLOCK used if it has a used variable in it, then recurse over its
subblocks. */
/* Mark the used attribute on blocks correctly. */
-static void
+static unsigned int
mark_used_blocks (void)
{
mark_blocks_with_used_vars (DECL_INITIAL (current_function_decl));
+ return 0;
}