-/* Tree lowering pass. Lowers GIMPLE into unstructured form.
+/* GIMPLE lowering pass. Converts High GIMPLE into Low GIMPLE.
- Copyright (C) 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
+ Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009
+ Free Software Foundation, Inc.
This file is part of GCC.
#include "tree.h"
#include "rtl.h"
#include "varray.h"
-#include "tree-gimple.h"
+#include "gimple.h"
+#include "tree-iterator.h"
#include "tree-inline.h"
#include "diagnostic.h"
#include "langhooks.h"
#include "toplev.h"
#include "tree-pass.h"
+/* The differences between High GIMPLE and Low GIMPLE are the
+ following:
+
+ 1- Lexical scopes are removed (i.e., GIMPLE_BIND disappears).
+
+ 2- GIMPLE_TRY and GIMPLE_CATCH are converted to abnormal control
+ flow and exception regions are built as an on-the-side region
+ hierarchy (See tree-eh.c:lower_eh_constructs).
+
+ 3- Multiple identical return statements are grouped into a single
+ return and gotos to the unique return site. */
+
+/* Match a return statement with a label. During lowering, we identify
+ identical return statements and replace duplicates with a jump to
+ the corresponding label. */
+struct return_statements_t
+{
+ tree label;
+ gimple stmt;
+};
+typedef struct return_statements_t return_statements_t;
+
+DEF_VEC_O(return_statements_t);
+DEF_VEC_ALLOC_O(return_statements_t,heap);
+
struct lower_data
{
/* Block the current statement belongs to. */
tree block;
- /* A TREE_LIST of label and return statements to be moved to the end
+ /* A vector of label and return statements to be moved to the end
of the function. */
- tree return_statements;
+ VEC(return_statements_t,heap) *return_statements;
+
+ /* True if the current statement cannot fall through. */
+ bool cannot_fallthru;
/* 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 void lower_builtin_setjmp (tree_stmt_iterator *);
+static void lower_stmt (gimple_stmt_iterator *, struct lower_data *);
+static void lower_gimple_bind (gimple_stmt_iterator *, struct lower_data *);
+static void lower_gimple_return (gimple_stmt_iterator *, struct lower_data *);
+static void lower_builtin_setjmp (gimple_stmt_iterator *);
-/* Lower the body of current_function_decl. */
+
+/* Lower the body of current_function_decl from High GIMPLE into Low
+ GIMPLE. */
static unsigned int
lower_function_body (void)
{
struct lower_data data;
- tree *body_p = &DECL_SAVED_TREE (current_function_decl);
- tree bind = *body_p;
- tree_stmt_iterator i;
- tree t, x;
-
- gcc_assert (TREE_CODE (bind) == BIND_EXPR);
+ gimple_seq body = gimple_body (current_function_decl);
+ gimple_seq lowered_body;
+ gimple_stmt_iterator i;
+ gimple bind;
+ tree t;
+ gimple x;
+
+ /* The gimplifier should've left a body of exactly one statement,
+ namely a GIMPLE_BIND. */
+ gcc_assert (gimple_seq_first (body) == gimple_seq_last (body)
+ && gimple_code (gimple_seq_first_stmt (body)) == GIMPLE_BIND);
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 = VEC_alloc (return_statements_t, heap, 8);
+
+ bind = gimple_seq_first_stmt (body);
+ lowered_body = NULL;
+ gimple_seq_add_stmt (&lowered_body, bind);
+ i = gsi_start (lowered_body);
+ lower_gimple_bind (&i, &data);
- *body_p = alloc_stmt_list ();
- i = tsi_start (*body_p);
- tsi_link_after (&i, bind, TSI_NEW_STMT);
- lower_bind_expr (&i, &data);
+ /* Once the old body has been lowered, replace it with the new
+ lowered sequence. */
+ gimple_set_body (current_function_decl, lowered_body);
- i = tsi_last (*body_p);
+ i = gsi_last (lowered_body);
/* If the function falls off the end, we need a null return statement.
- If we've already got one in the return_statements list, we don't
+ If we've already got one in the return_statements vector, we don't
need to do anything special. Otherwise build one by hand. */
- if (block_may_fallthru (*body_p)
- && (data.return_statements == NULL
- || TREE_OPERAND (TREE_VALUE (data.return_statements), 0) != NULL))
+ if (gimple_seq_may_fallthru (lowered_body)
+ && (VEC_empty (return_statements_t, data.return_statements)
+ || gimple_return_retval (VEC_last (return_statements_t,
+ data.return_statements)->stmt) != 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);
+ x = gimple_build_return (NULL);
+ gimple_set_location (x, cfun->function_end_locus);
+ gimple_set_block (x, DECL_INITIAL (current_function_decl));
+ gsi_insert_after (&i, x, GSI_CONTINUE_LINKING);
}
/* If we lowered any return statements, emit the representative
at the end of the function. */
- for (t = data.return_statements ; t ; t = TREE_CHAIN (t))
+ while (!VEC_empty (return_statements_t, data.return_statements))
{
- x = build1 (LABEL_EXPR, void_type_node, TREE_PURPOSE (t));
- tsi_link_after (&i, x, TSI_CONTINUE_LINKING);
+ return_statements_t t;
+
+ /* Unfortunately, we can't use VEC_pop because it returns void for
+ objects. */
+ t = *VEC_last (return_statements_t, data.return_statements);
+ VEC_truncate (return_statements_t,
+ data.return_statements,
+ VEC_length (return_statements_t,
+ data.return_statements) - 1);
+
+ x = gimple_build_label (t.label);
+ gsi_insert_after (&i, x, GSI_CONTINUE_LINKING);
/* Remove the line number from the representative return statement.
It now fills in for many such returns. Failure to remove this
will result in incorrect results for coverage analysis. */
- x = TREE_VALUE (t);
-#ifdef USE_MAPPED_LOCATION
- SET_EXPR_LOCATION (x, UNKNOWN_LOCATION);
-#else
- SET_EXPR_LOCUS (x, NULL);
-#endif
- tsi_link_after (&i, x, TSI_CONTINUE_LINKING);
+ gimple_set_location (t.stmt, UNKNOWN_LOCATION);
+ gsi_insert_after (&i, t.stmt, GSI_CONTINUE_LINKING);
}
/* If the function calls __builtin_setjmp, we need to emit the computed
tree disp_label, disp_var, arg;
/* Build 'DISP_LABEL:' and insert. */
- disp_label = create_artificial_label ();
+ disp_label = create_artificial_label (cfun->function_end_locus);
/* 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);
+ cfun->has_nonlocal_label = 1;
+ x = gimple_build_label (disp_label);
+ gsi_insert_after (&i, x, GSI_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);
+ x = gimple_build_call (t, 1, arg);
+ gimple_call_set_lhs (x, disp_var);
/* 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);
+ gsi_insert_after (&i, x, GSI_CONTINUE_LINKING);
+ x = gimple_build_goto (disp_var);
+ gsi_insert_after (&i, x, GSI_CONTINUE_LINKING);
}
gcc_assert (data.block == DECL_INITIAL (current_function_decl));
= blocks_nreverse (BLOCK_SUBBLOCKS (data.block));
clear_block_marks (data.block);
+ VEC_free(return_statements_t, heap, data.return_statements);
return 0;
}
-struct tree_opt_pass pass_lower_cf =
+struct gimple_opt_pass pass_lower_cf =
{
+ {
+ GIMPLE_PASS,
"lower", /* name */
NULL, /* gate */
lower_function_body, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
- 0, /* tv_id */
+ TV_NONE, /* tv_id */
PROP_gimple_any, /* properties_required */
PROP_gimple_lcf, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_dump_func, /* todo_flags_finish */
- 0 /* letter */
+ TODO_dump_func /* todo_flags_finish */
+ }
};
-/* Lower the EXPR. Unlike gimplification the statements are not relowered
+/* Verify if the type of the argument matches that of the function
+ declaration. If we cannot verify this or there is a mismatch,
+ return false. */
+
+bool
+gimple_check_call_args (gimple stmt)
+{
+ tree fndecl, parms, p;
+ unsigned int i, nargs;
+
+ nargs = gimple_call_num_args (stmt);
+
+ /* Get argument types for verification. */
+ fndecl = gimple_call_fndecl (stmt);
+ parms = NULL_TREE;
+ if (fndecl)
+ parms = TYPE_ARG_TYPES (TREE_TYPE (fndecl));
+ else if (POINTER_TYPE_P (TREE_TYPE (gimple_call_fn (stmt))))
+ parms = TYPE_ARG_TYPES (TREE_TYPE (TREE_TYPE (gimple_call_fn (stmt))));
+
+ /* Verify if the type of the argument matches that of the function
+ declaration. If we cannot verify this or there is a mismatch,
+ return false. */
+ if (fndecl && DECL_ARGUMENTS (fndecl))
+ {
+ for (i = 0, p = DECL_ARGUMENTS (fndecl);
+ i < nargs;
+ i++, p = TREE_CHAIN (p))
+ {
+ /* We cannot distinguish a varargs function from the case
+ of excess parameters, still deferring the inlining decision
+ to the callee is possible. */
+ if (!p)
+ break;
+ if (p == error_mark_node
+ || gimple_call_arg (stmt, i) == error_mark_node
+ || !fold_convertible_p (DECL_ARG_TYPE (p),
+ gimple_call_arg (stmt, i)))
+ return false;
+ }
+ }
+ else if (parms)
+ {
+ for (i = 0, p = parms; i < nargs; i++, p = TREE_CHAIN (p))
+ {
+ /* If this is a varargs function defer inlining decision
+ to callee. */
+ if (!p)
+ break;
+ if (TREE_VALUE (p) == error_mark_node
+ || gimple_call_arg (stmt, i) == error_mark_node
+ || TREE_CODE (TREE_VALUE (p)) == VOID_TYPE
+ || !fold_convertible_p (TREE_VALUE (p),
+ gimple_call_arg (stmt, i)))
+ return false;
+ }
+ }
+ else
+ {
+ if (nargs != 0)
+ return false;
+ }
+ return true;
+}
+
+
+/* Lower sequence SEQ. 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. */
static void
-lower_stmt_body (tree expr, struct lower_data *data)
+lower_sequence (gimple_seq seq, struct lower_data *data)
{
- tree_stmt_iterator tsi;
+ gimple_stmt_iterator gsi;
- for (tsi = tsi_start (expr); !tsi_end_p (tsi); )
- lower_stmt (&tsi, data);
+ for (gsi = gsi_start (seq); !gsi_end_p (gsi); )
+ lower_stmt (&gsi, data);
}
-/* Lower the OpenMP directive statement pointed by TSI. DATA is
+/* Lower the OpenMP directive statement pointed by GSI. DATA is
passed through the recursion. */
static void
-lower_omp_directive (tree_stmt_iterator *tsi, struct lower_data *data)
+lower_omp_directive (gimple_stmt_iterator *gsi, 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);
+ gimple stmt;
+
+ stmt = gsi_stmt (*gsi);
+
+ lower_sequence (gimple_omp_body (stmt), data);
+ gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
+ gsi_insert_seq_before (gsi, gimple_omp_body (stmt), GSI_SAME_STMT);
+ gimple_omp_set_body (stmt, NULL);
+ gsi_remove (gsi, false);
}
-/* Lower statement TSI. DATA is passed through the recursion. */
+/* Lower statement GSI. DATA is passed through the recursion. We try to
+ track the fallthruness of statements and get rid of unreachable return
+ statements in order to prevent the EH lowering pass from adding useless
+ edges that can cause bogus warnings to be issued later; this guess need
+ not be 100% accurate, simply be conservative and reset cannot_fallthru
+ to false if we don't know. */
static void
-lower_stmt (tree_stmt_iterator *tsi, struct lower_data *data)
+lower_stmt (gimple_stmt_iterator *gsi, struct lower_data *data)
{
- tree stmt = tsi_stmt (*tsi);
+ gimple stmt = gsi_stmt (*gsi);
- if (EXPR_HAS_LOCATION (stmt) && data)
- TREE_BLOCK (stmt) = data->block;
+ gimple_set_block (stmt, data->block);
- switch (TREE_CODE (stmt))
+ switch (gimple_code (stmt))
{
- case BIND_EXPR:
- lower_bind_expr (tsi, data);
+ case GIMPLE_BIND:
+ lower_gimple_bind (gsi, data);
+ /* Propagate fallthruness. */
return;
- case COND_EXPR:
- lower_cond_expr (tsi, data);
+
+ case GIMPLE_COND:
+ case GIMPLE_GOTO:
+ case GIMPLE_SWITCH:
+ data->cannot_fallthru = true;
+ gsi_next (gsi);
return;
- case RETURN_EXPR:
- lower_return_expr (tsi, data);
+
+ case GIMPLE_RETURN:
+ if (data->cannot_fallthru)
+ {
+ gsi_remove (gsi, false);
+ /* Propagate fallthruness. */
+ }
+ else
+ {
+ lower_gimple_return (gsi, data);
+ data->cannot_fallthru = true;
+ }
return;
- case TRY_FINALLY_EXPR:
- case TRY_CATCH_EXPR:
- lower_stmt_body (TREE_OPERAND (stmt, 0), data);
- lower_stmt_body (TREE_OPERAND (stmt, 1), data);
- break;
- case CATCH_EXPR:
- lower_stmt_body (CATCH_BODY (stmt), data);
+ case GIMPLE_TRY:
+ {
+ bool try_cannot_fallthru;
+ lower_sequence (gimple_try_eval (stmt), data);
+ try_cannot_fallthru = data->cannot_fallthru;
+ data->cannot_fallthru = false;
+ lower_sequence (gimple_try_cleanup (stmt), data);
+ /* See gimple_stmt_may_fallthru for the rationale. */
+ if (gimple_try_kind (stmt) == GIMPLE_TRY_FINALLY)
+ {
+ data->cannot_fallthru |= try_cannot_fallthru;
+ gsi_next (gsi);
+ return;
+ }
+ }
break;
- case EH_FILTER_EXPR:
- lower_stmt_body (EH_FILTER_FAILURE (stmt), data);
+
+ case GIMPLE_CATCH:
+ data->cannot_fallthru = false;
+ lower_sequence (gimple_catch_handler (stmt), data);
break;
-
- case NOP_EXPR:
- case ASM_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:
+
+ case GIMPLE_EH_FILTER:
+ data->cannot_fallthru = false;
+ lower_sequence (gimple_eh_filter_failure (stmt), data);
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 GIMPLE_NOP:
+ case GIMPLE_ASM:
+ case GIMPLE_ASSIGN:
+ case GIMPLE_PREDICT:
+ case GIMPLE_LABEL:
+ case GIMPLE_EH_MUST_NOT_THROW:
+ case GIMPLE_OMP_FOR:
+ case GIMPLE_OMP_SECTIONS:
+ case GIMPLE_OMP_SECTIONS_SWITCH:
+ case GIMPLE_OMP_SECTION:
+ case GIMPLE_OMP_SINGLE:
+ case GIMPLE_OMP_MASTER:
+ case GIMPLE_OMP_ORDERED:
+ case GIMPLE_OMP_CRITICAL:
+ case GIMPLE_OMP_RETURN:
+ case GIMPLE_OMP_ATOMIC_LOAD:
+ case GIMPLE_OMP_ATOMIC_STORE:
+ case GIMPLE_OMP_CONTINUE:
+ break;
- case CALL_EXPR:
+ case GIMPLE_CALL:
{
- tree decl = get_callee_fndecl (stmt);
+ tree decl = gimple_call_fndecl (stmt);
+
if (decl
&& DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL
&& DECL_FUNCTION_CODE (decl) == BUILT_IN_SETJMP)
{
+ lower_builtin_setjmp (gsi);
+ data->cannot_fallthru = false;
data->calls_builtin_setjmp = true;
- lower_builtin_setjmp (tsi);
+ return;
+ }
+
+ if (decl && (flags_from_decl_or_type (decl) & ECF_NORETURN))
+ {
+ data->cannot_fallthru = true;
+ gsi_next (gsi);
return;
}
}
break;
- case OMP_PARALLEL:
- lower_omp_directive (tsi, data);
+ case GIMPLE_OMP_PARALLEL:
+ case GIMPLE_OMP_TASK:
+ data->cannot_fallthru = false;
+ lower_omp_directive (gsi, data);
+ data->cannot_fallthru = false;
return;
default:
gcc_unreachable ();
}
- tsi_next (tsi);
+ data->cannot_fallthru = false;
+ gsi_next (gsi);
}
/* Lower a bind_expr TSI. DATA is passed through the recursion. */
static void
-lower_bind_expr (tree_stmt_iterator *tsi, struct lower_data *data)
+lower_gimple_bind (gimple_stmt_iterator *gsi, struct lower_data *data)
{
tree old_block = data->block;
- tree stmt = tsi_stmt (*tsi);
- tree new_block = BIND_EXPR_BLOCK (stmt);
+ gimple stmt = gsi_stmt (*gsi);
+ tree new_block = gimple_bind_block (stmt);
if (new_block)
{
}
}
- record_vars (BIND_EXPR_VARS (stmt));
- lower_stmt_body (BIND_EXPR_BODY (stmt), data);
+ record_vars (gimple_bind_vars (stmt));
+ lower_sequence (gimple_bind_body (stmt), data);
if (new_block)
{
data->block = old_block;
}
- /* The BIND_EXPR no longer carries any useful information -- kill it. */
- tsi_link_before (tsi, BIND_EXPR_BODY (stmt), TSI_SAME_STMT);
- tsi_delink (tsi);
+ /* The GIMPLE_BIND no longer carries any useful information -- kill it. */
+ gsi_insert_seq_before (gsi, gimple_bind_body (stmt), GSI_SAME_STMT);
+ gsi_remove (gsi, false);
}
/* Try to determine whether a TRY_CATCH expression can fall through.
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. */
+ by a RESX statement to resume execution after the exception.
+ So in this case the TRY_CATCH never falls through. */
+ return false;
+ }
+}
+
+
+/* Same as above, but for a GIMPLE_TRY_CATCH. */
+
+static bool
+gimple_try_catch_may_fallthru (gimple stmt)
+{
+ gimple_stmt_iterator i;
+
+ /* We don't handle GIMPLE_TRY_FINALLY. */
+ gcc_assert (gimple_try_kind (stmt) == GIMPLE_TRY_CATCH);
+
+ /* If the TRY block can fall through, the whole TRY_CATCH can
+ fall through. */
+ if (gimple_seq_may_fallthru (gimple_try_eval (stmt)))
+ return true;
+
+ i = gsi_start (gimple_try_cleanup (stmt));
+ switch (gimple_code (gsi_stmt (i)))
+ {
+ case GIMPLE_CATCH:
+ /* We expect to see a sequence of GIMPLE_CATCH stmts, each with a
+ catch expression and a body. The whole try/catch may fall
+ through iff any of the catch bodies falls through. */
+ for (; !gsi_end_p (i); gsi_next (&i))
+ {
+ if (gimple_seq_may_fallthru (gimple_catch_handler (gsi_stmt (i))))
+ return true;
+ }
+ return false;
+
+ case GIMPLE_EH_FILTER:
+ /* 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 gimple_seq_may_fallthru (gimple_eh_filter_failure (gsi_stmt (i)));
+
+ default:
+ /* This case represents statements to be executed when an
+ exception occurs. Those statements are implicitly followed
+ by a GIMPLE_RESX 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.
bool
block_may_fallthru (const_tree block)
{
- const_tree stmt = const_expr_last (block);
+ /* This CONST_CAST is okay because expr_last returns its 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:
- /* Easy cases. If the last statement of the block implies
+ /* Easy cases. If the last statement of the block implies
control transfer, then we can't fall through. */
return false;
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);
+ 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));
}
}
-/* Lower a cond_expr TSI. DATA is passed through the recursion. */
-static void
-lower_cond_expr (tree_stmt_iterator *tsi, struct lower_data *data)
+/* Try to determine if we can continue executing the statement
+ immediately following STMT. 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
+gimple_stmt_may_fallthru (gimple stmt)
{
- 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);
+ if (!stmt)
+ return true;
- lower_stmt_body (then_branch, data);
- lower_stmt_body (else_branch, data);
+ switch (gimple_code (stmt))
+ {
+ case GIMPLE_GOTO:
+ case GIMPLE_RETURN:
+ case GIMPLE_RESX:
+ /* Easy cases. If the last statement of the seq implies
+ control transfer, then we can't fall through. */
+ return false;
- then_goto = expr_only (then_branch);
- then_is_goto = then_goto && simple_goto_p (then_goto);
+ case GIMPLE_SWITCH:
+ /* Switch has already been lowered and represents a branch
+ to a selected label and hence can't fall through. */
+ return false;
- else_goto = expr_only (else_branch);
- else_is_goto = else_goto && simple_goto_p (else_goto);
+ case GIMPLE_COND:
+ /* GIMPLE_COND's are already lowered into a two-way branch. They
+ can't fall through. */
+ return false;
- 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));
- }
+ case GIMPLE_BIND:
+ return gimple_seq_may_fallthru (gimple_bind_body (stmt));
- 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));
- }
+ case GIMPLE_TRY:
+ if (gimple_try_kind (stmt) == GIMPLE_TRY_CATCH)
+ return gimple_try_catch_may_fallthru (stmt);
- 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);
- }
+ /* It must be a GIMPLE_TRY_FINALLY. */
- if (end_label)
- tsi_link_after (tsi, end_label, TSI_CONTINUE_LINKING);
+ /* 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 (gimple_seq_may_fallthru (gimple_try_eval (stmt))
+ && gimple_seq_may_fallthru (gimple_try_cleanup (stmt)));
+
+ case GIMPLE_CALL:
+ /* Functions that do not return do not fall through. */
+ return (gimple_call_flags (stmt) & ECF_NORETURN) == 0;
+
+ default:
+ return true;
}
+}
- COND_EXPR_THEN (stmt) = then_goto;
- COND_EXPR_ELSE (stmt) = else_goto;
- tsi_next (tsi);
+/* Same as gimple_stmt_may_fallthru, but for the gimple sequence SEQ. */
+
+bool
+gimple_seq_may_fallthru (gimple_seq seq)
+{
+ return gimple_stmt_may_fallthru (gimple_seq_last_stmt (seq));
}
-/* Lower a return_expr TSI. DATA is passed through the recursion. */
+
+/* Lower a GIMPLE_RETURN GSI. DATA is passed through the recursion. */
static void
-lower_return_expr (tree_stmt_iterator *tsi, struct lower_data *data)
+lower_gimple_return (gimple_stmt_iterator *gsi, 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) == GIMPLE_MODIFY_STMT)
- value = GIMPLE_STMT_OPERAND (value, 1);
+ gimple stmt = gsi_stmt (*gsi);
+ gimple t;
+ int i;
+ return_statements_t tmp_rs;
/* Match this up with an existing return statement that's been created. */
- for (t = data->return_statements; t ; t = TREE_CHAIN (t))
+ for (i = VEC_length (return_statements_t, data->return_statements) - 1;
+ i >= 0; i--)
{
- tree tvalue = TREE_OPERAND (TREE_VALUE (t), 0);
- if (tvalue && TREE_CODE (tvalue) == GIMPLE_MODIFY_STMT)
- tvalue = GIMPLE_STMT_OPERAND (tvalue, 1);
+ tmp_rs = *VEC_index (return_statements_t, data->return_statements, i);
- if (value == tvalue)
- {
- label = TREE_PURPOSE (t);
- goto found;
- }
+ if (gimple_return_retval (stmt) == gimple_return_retval (tmp_rs.stmt))
+ 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);
+ tmp_rs.label = create_artificial_label (cfun->function_end_locus);
+ tmp_rs.stmt = stmt;
+ VEC_safe_push (return_statements_t, heap, data->return_statements, &tmp_rs);
/* 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);
+ t = gimple_build_goto (tmp_rs.label);
+ gimple_set_location (t, gimple_location (stmt));
+ gimple_set_block (t, gimple_block (stmt));
+ gsi_insert_before (gsi, t, GSI_SAME_STMT);
+ gsi_remove (gsi, false);
}
-/* Lower a __builtin_setjmp TSI.
+/* Lower a __builtin_setjmp GSI.
__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
to the receivers, thus keeping the complexity explosion localized. */
static void
-lower_builtin_setjmp (tree_stmt_iterator *tsi)
+lower_builtin_setjmp (gimple_stmt_iterator *gsi)
{
- tree stmt = tsi_stmt (*tsi);
- tree cont_label = create_artificial_label ();
- tree next_label = create_artificial_label ();
+ gimple stmt = gsi_stmt (*gsi);
+ location_t loc = gimple_location (stmt);
+ tree cont_label = create_artificial_label (loc);
+ tree next_label = create_artificial_label (loc);
tree dest, t, arg;
+ gimple g;
/* 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) == GIMPLE_MODIFY_STMT)
- {
- dest = GIMPLE_STMT_OPERAND (stmt, 0);
- stmt = GIMPLE_STMT_OPERAND (stmt, 1);
- }
- else
- dest = NULL_TREE;
+ dest = gimple_call_lhs (stmt);
/* 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);
+ g = gimple_build_call (t, 2, gimple_call_arg (stmt, 0), arg);
+ gimple_set_location (g, loc);
+ gimple_set_block (g, gimple_block (stmt));
+ gsi_insert_before (gsi, g, GSI_SAME_STMT);
/* 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);
+ g = gimple_build_assign (dest, fold_convert_loc (loc, TREE_TYPE (dest),
+ integer_zero_node));
+ gimple_set_location (g, loc);
+ gimple_set_block (g, gimple_block (stmt));
+ gsi_insert_before (gsi, g, GSI_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);
+ g = gimple_build_goto (cont_label);
+ gsi_insert_before (gsi, g, GSI_SAME_STMT);
/* Build 'NEXT_LABEL:' and insert. */
- t = build1 (LABEL_EXPR, void_type_node, next_label);
- tsi_link_before (tsi, t, TSI_SAME_STMT);
+ g = gimple_build_label (next_label);
+ gsi_insert_before (gsi, g, GSI_SAME_STMT);
/* 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);
+ g = gimple_build_call (t, 1, arg);
+ gimple_set_location (g, loc);
+ gimple_set_block (g, gimple_block (stmt));
+ gsi_insert_before (gsi, g, GSI_SAME_STMT);
/* Build 'DEST = 1' and insert. */
if (dest)
{
- 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);
+ g = gimple_build_assign (dest, fold_convert_loc (loc, TREE_TYPE (dest),
+ integer_one_node));
+ gimple_set_location (g, loc);
+ gimple_set_block (g, gimple_block (stmt));
+ gsi_insert_before (gsi, g, GSI_SAME_STMT);
}
/* Build 'CONT_LABEL:' and insert. */
- t = build1 (LABEL_EXPR, void_type_node, cont_label);
- tsi_link_before (tsi, t, TSI_SAME_STMT);
+ g = gimple_build_label (cont_label);
+ gsi_insert_before (gsi, g, GSI_SAME_STMT);
/* Remove the call to __builtin_setjmp. */
- tsi_delink (tsi);
+ gsi_remove (gsi, false);
}
\f
void
record_vars_into (tree vars, tree fn)
{
- struct function *saved_cfun = cfun;
-
if (fn != current_function_decl)
- cfun = DECL_STRUCT_FUNCTION (fn);
+ push_cfun (DECL_STRUCT_FUNCTION (fn));
for (; vars; vars = TREE_CHAIN (vars))
{
continue;
/* Record the variable. */
- cfun->unexpanded_var_list = tree_cons (NULL_TREE, var,
- cfun->unexpanded_var_list);
+ cfun->local_decls = tree_cons (NULL_TREE, var,
+ cfun->local_decls);
}
if (fn != current_function_decl)
- cfun = saved_cfun;
+ pop_cfun ();
}
{
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 */
-};
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