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Diffstat (limited to 'gcc/c-iterate.c')
| -rw-r--r-- | gcc/c-iterate.c | 587 |
1 files changed, 0 insertions, 587 deletions
diff --git a/gcc/c-iterate.c b/gcc/c-iterate.c deleted file mode 100644 index 0e545d80d9d..00000000000 --- a/gcc/c-iterate.c +++ /dev/null @@ -1,587 +0,0 @@ -/* Build expressions with type checking for C compiler. - Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996 - 1997, 1998, 2000 Free Software Foundation, Inc. - -This file is part of GNU CC. - -GNU CC 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 version. - -GNU CC is distributed in the hope that it will be useful, -but WITHOUT ANY WARRANTY; without even the implied warranty of -MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -GNU General Public License for more details. - -You should have received a copy of the GNU General Public License -along with GNU CC; see the file COPYING. If not, write to -the Free Software Foundation, 59 Temple Place - Suite 330, -Boston, MA 02111-1307, USA. */ - - -/* This file is part of the C front end. - It is responsible for implementing iterators, - both their declarations and the expansion of statements using them. */ - -#include "config.h" -#include "system.h" -#include "tree.h" -#include "c-tree.h" -#include "flags.h" -#include "obstack.h" -#include "rtl.h" -#include "toplev.h" -#include "expr.h" - -/* - KEEPING TRACK OF EXPANSIONS - - In order to clean out expansions corresponding to statements inside - "{(...)}" constructs we have to keep track of all expansions. The - cleanup is needed when an automatic, or implicit, expansion on - iterator, say X, happens to a statement which contains a {(...)} - form with a statement already expanded on X. In this case we have - to go back and cleanup the inner expansion. This can be further - complicated by the fact that {(...)} can be nested. - - To make this cleanup possible, we keep lists of all expansions, and - to make it work for nested constructs, we keep a stack. The list at - the top of the stack (ITER_STACK.CURRENT_LEVEL) corresponds to the - currently parsed level. All expansions of the levels below the - current one are kept in one list whose head is pointed to by - ITER_STACK.SUBLEVEL_FIRST (SUBLEVEL_LAST is there for making merges - easy). The process works as follows: - - -- On "({" a new node is added to the stack by PUSH_ITERATOR_STACK. - The sublevel list is not changed at this point. - - -- On "})" the list for the current level is appended to the sublevel - list. - - -- On ";" sublevel lists are appended to the current level lists. - The reason is this: if they have not been superseded by the - expansion at the current level, they still might be - superseded later by the expansion on the higher level. - The levels do not have to distinguish levels below, so we - can merge the lists together. */ - -struct ixpansion -{ - tree ixdecl; /* Iterator decl */ - rtx ixprologue_start; /* First insn of epilogue. NULL means */ - /* explicit (FOR) expansion*/ - rtx ixprologue_end; - rtx ixepilogue_start; - rtx ixepilogue_end; - struct ixpansion *next; /* Next in the list */ -}; - -struct iter_stack_node -{ - struct ixpansion *first; /* Head of list of ixpansions */ - struct ixpansion *last; /* Last node in list of ixpansions */ - struct iter_stack_node *next; /* Next level iterator stack node */ -}; - -struct iter_stack_node *iter_stack; -struct iter_stack_node sublevel_ixpansions; - -/* A special obstack, and a pointer to the start of - all the data in it (so we can free everything easily). */ -static struct obstack ixp_obstack; -static char *ixp_firstobj; - -/* During collect_iterators, a list of SAVE_EXPRs already scanned. */ -static tree save_exprs; - -static void expand_stmt_with_iterators_1 PARAMS ((tree, tree)); -static tree collect_iterators PARAMS ((tree, tree)); -static void iterator_loop_prologue PARAMS ((tree, rtx *, rtx *)); -static void iterator_loop_epilogue PARAMS ((tree, rtx *, rtx *)); -static int top_level_ixpansion_p PARAMS ((void)); -static void isn_append PARAMS ((struct iter_stack_node *, - struct iter_stack_node *)); -static void istack_sublevel_to_current PARAMS ((void)); -static void add_ixpansion PARAMS ((tree, rtx, rtx, rtx, rtx)); -static void delete_ixpansion PARAMS ((tree)); - -/* Initialize our obstack once per compilation. */ - -void -init_iterators () -{ - gcc_obstack_init (&ixp_obstack); - ixp_firstobj = (char *) obstack_alloc (&ixp_obstack, 0); -} - -/* Handle the start of an explicit `for' loop for iterator IDECL. */ - -void -iterator_for_loop_start (idecl) - tree idecl; -{ - ITERATOR_BOUND_P (idecl) = 1; - add_ixpansion (idecl, 0, 0, 0, 0); - iterator_loop_prologue (idecl, 0, 0); -} - -/* Handle the end of an explicit `for' loop for iterator IDECL. */ - -void -iterator_for_loop_end (idecl) - tree idecl; -{ - iterator_loop_epilogue (idecl, 0, 0); - ITERATOR_BOUND_P (idecl) = 0; -} - -/* - ITERATOR RTL EXPANSIONS - - Expanding simple statements with iterators is straightforward: - collect the list of all free iterators in the statement, and - generate a loop for each of them. - - An iterator is "free" if it has not been "bound" by a FOR - operator. The DECL_RTL of the iterator is the loop counter. */ - -/* Expand a statement STMT, possibly containing iterator usage, into RTL. */ - -void -iterator_expand (stmt) - tree stmt; -{ - tree iter_list; - save_exprs = NULL_TREE; - iter_list = collect_iterators (stmt, NULL_TREE); - expand_stmt_with_iterators_1 (stmt, iter_list); - istack_sublevel_to_current (); -} - - -static void -expand_stmt_with_iterators_1 (stmt, iter_list) - tree stmt, iter_list; -{ - if (iter_list == 0) - expand_expr_stmt (stmt); - else - { - tree current_iterator = TREE_VALUE (iter_list); - tree iter_list_tail = TREE_CHAIN (iter_list); - rtx p_start, p_end, e_start, e_end; - - iterator_loop_prologue (current_iterator, &p_start, &p_end); - expand_stmt_with_iterators_1 (stmt, iter_list_tail); - iterator_loop_epilogue (current_iterator, &e_start, &e_end); - - /** Delete all inner expansions based on current_iterator **/ - /** before adding the outer one. **/ - - delete_ixpansion (current_iterator); - add_ixpansion (current_iterator, p_start, p_end, e_start, e_end); - } -} - - -/* Return a list containing all the free (i.e. not bound by a - containing `for' statement) iterators mentioned in EXP, plus those - in LIST. Do not add duplicate entries to the list. */ - -static tree -collect_iterators (exp, list) - tree exp, list; -{ - if (exp == 0) return list; - - switch (TREE_CODE (exp)) - { - case VAR_DECL: - if (! ITERATOR_P (exp) || ITERATOR_BOUND_P (exp)) - return list; - if (value_member (exp, list)) - return list; - return tree_cons (NULL_TREE, exp, list); - - case TREE_LIST: - { - tree tail; - for (tail = exp; tail; tail = TREE_CHAIN (tail)) - list = collect_iterators (TREE_VALUE (tail), list); - return list; - } - - case SAVE_EXPR: - /* In each scan, scan a given save_expr only once. */ - if (value_member (exp, save_exprs)) - return list; - - save_exprs = tree_cons (NULL_TREE, exp, save_exprs); - return collect_iterators (TREE_OPERAND (exp, 0), list); - - /* we do not automatically iterate blocks -- one must */ - /* use the FOR construct to do that */ - - case BLOCK: - return list; - - default: - switch (TREE_CODE_CLASS (TREE_CODE (exp))) - { - case '1': - return collect_iterators (TREE_OPERAND (exp, 0), list); - - case '2': - case '<': - return collect_iterators (TREE_OPERAND (exp, 0), - collect_iterators (TREE_OPERAND (exp, 1), - list)); - - case 'e': - case 'r': - { - int num_args = first_rtl_op (TREE_CODE (exp)); - int i; - - for (i = 0; i < num_args; i++) - list = collect_iterators (TREE_OPERAND (exp, i), list); - return list; - } - default: - return list; - } - } -} - -/* Emit rtl for the start of a loop for iterator IDECL. - - If necessary, create loop counter rtx and store it as DECL_RTL of IDECL. - - The prologue normally starts and ends with notes, which are returned - by this function in *START_NOTE and *END_NODE. - If START_NOTE and END_NODE are 0, we don't make those notes. */ - -static void -iterator_loop_prologue (idecl, start_note, end_note) - tree idecl; - rtx *start_note, *end_note; -{ - tree expr; - - /* Force the save_expr in DECL_INITIAL to be calculated - if it hasn't been calculated yet. */ - expand_expr (DECL_INITIAL (idecl), const0_rtx, VOIDmode, - EXPAND_NORMAL); - - if (DECL_RTL (idecl) == 0) - expand_decl (idecl); - - if (start_note) - *start_note = emit_note (0, NOTE_INSN_DELETED); - - /* Initialize counter. */ - expr = build (MODIFY_EXPR, TREE_TYPE (idecl), idecl, integer_zero_node); - TREE_SIDE_EFFECTS (expr) = 1; - expand_expr (expr, const0_rtx, VOIDmode, EXPAND_NORMAL); - - expand_start_loop_continue_elsewhere (1); - - ITERATOR_BOUND_P (idecl) = 1; - - if (end_note) - *end_note = emit_note (0, NOTE_INSN_DELETED); -} - -/* Similar to the previous function, but for the end of the loop. - - DECL_RTL is zeroed unless we are inside "({...})". The reason for that is - described below. - - When we create two (or more) loops based on the same IDECL, and - both inside the same "({...})" construct, we must be prepared to - delete both of the loops and create a single one on the level - above, i.e. enclosing the "({...})". The new loop has to use the - same counter rtl because the references to the iterator decl - (IDECL) have already been expanded as references to the counter - rtl. - - It is incorrect to use the same counter reg in different functions, - and it is desirable to use different counters in disjoint loops - when we know there's no need to combine them (because then they can - get allocated separately). */ - -static void -iterator_loop_epilogue (idecl, start_note, end_note) - tree idecl; - rtx *start_note, *end_note; -{ - tree test, incr; - - if (start_note) - *start_note = emit_note (0, NOTE_INSN_DELETED); - expand_loop_continue_here (); - incr = build_binary_op (PLUS_EXPR, idecl, integer_one_node, 0); - incr = build (MODIFY_EXPR, TREE_TYPE (idecl), idecl, incr); - TREE_SIDE_EFFECTS (incr) = 1; - expand_expr (incr, const0_rtx, VOIDmode, EXPAND_NORMAL); - test = build_binary_op (LT_EXPR, idecl, DECL_INITIAL (idecl), 0); - expand_exit_loop_if_false (0, test); - expand_end_loop (); - - ITERATOR_BOUND_P (idecl) = 0; - /* we can reset rtl since there is not chance that this expansion */ - /* would be superseded by a higher level one */ - /* but don't do this if the decl is static, since we need to share */ - /* the same decl in that case. */ - if (top_level_ixpansion_p () && ! TREE_STATIC (idecl)) - DECL_RTL (idecl) = 0; - if (end_note) - *end_note = emit_note (0, NOTE_INSN_DELETED); -} - -/* Return true if we are not currently inside a "({...})" construct. */ - -static int -top_level_ixpansion_p () -{ - return iter_stack == 0; -} - -/* Given two chains of iter_stack_nodes, - append the nodes in X into Y. */ - -static void -isn_append (x, y) - struct iter_stack_node *x, *y; -{ - if (x->first == 0) - return; - - if (y->first == 0) - { - y->first = x->first; - y->last = x->last; - } - else - { - y->last->next = x->first; - y->last = x->last; - } -} - -/** Make X empty **/ - -#define ISN_ZERO(X) (X).first=(X).last=0 - -/* Move the ixpansions in sublevel_ixpansions into the current - node on the iter_stack, or discard them if the iter_stack is empty. - We do this at the end of a statement. */ - -static void -istack_sublevel_to_current () -{ - /* At the top level we can throw away sublevel's expansions **/ - /* because there is nobody above us to ask for a cleanup **/ - if (iter_stack != 0) - /** Merging with empty sublevel list is a no-op **/ - if (sublevel_ixpansions.last) - isn_append (&sublevel_ixpansions, iter_stack); - - if (iter_stack == 0) - obstack_free (&ixp_obstack, ixp_firstobj); - - ISN_ZERO (sublevel_ixpansions); -} - -/* Push a new node on the iter_stack, when we enter a ({...}). */ - -void -push_iterator_stack () -{ - struct iter_stack_node *new_top - = (struct iter_stack_node *) - obstack_alloc (&ixp_obstack, sizeof (struct iter_stack_node)); - - new_top->first = 0; - new_top->last = 0; - new_top->next = iter_stack; - iter_stack = new_top; -} - -/* Pop iter_stack, moving the ixpansions in the node being popped - into sublevel_ixpansions. */ - -void -pop_iterator_stack () -{ - if (iter_stack == 0) - abort (); - - isn_append (iter_stack, &sublevel_ixpansions); - /** Pop current level node: */ - iter_stack = iter_stack->next; -} - - -/* Record an iterator expansion ("ixpansion") for IDECL. - The remaining parameters are the notes in the loop entry - and exit rtl. */ - -static void -add_ixpansion (idecl, pro_start, pro_end, epi_start, epi_end) - tree idecl; - rtx pro_start, pro_end, epi_start, epi_end; -{ - struct ixpansion *newix; - - /* Do nothing if we are not inside "({...})", - as in that case this expansion can't need subsequent RTL modification. */ - if (iter_stack == 0) - return; - - newix = (struct ixpansion *) obstack_alloc (&ixp_obstack, - sizeof (struct ixpansion)); - newix->ixdecl = idecl; - newix->ixprologue_start = pro_start; - newix->ixprologue_end = pro_end; - newix->ixepilogue_start = epi_start; - newix->ixepilogue_end = epi_end; - - newix->next = iter_stack->first; - iter_stack->first = newix; - if (iter_stack->last == 0) - iter_stack->last = newix; -} - -/* Delete the RTL for all ixpansions for iterator IDECL - in our sublevels. We do this when we make a larger - containing expansion for IDECL. */ - -static void -delete_ixpansion (idecl) - tree idecl; -{ - struct ixpansion *previx = 0, *ix; - - for (ix = sublevel_ixpansions.first; ix; ix = ix->next) - if (ix->ixdecl == idecl) - { - /** zero means that this is a mark for FOR -- **/ - /** we do not delete anything, just issue an error. **/ - - if (ix->ixprologue_start == 0) - error_with_decl (idecl, - "`for (%s)' appears within implicit iteration"); - else - { - rtx insn; - /* We delete all insns, including notes because leaving loop */ - /* notes and barriers produced by iterator expansion would */ - /* be misleading to other phases */ - - for (insn = NEXT_INSN (ix->ixprologue_start); - insn != ix->ixprologue_end; - insn = NEXT_INSN (insn)) - delete_insn (insn); - for (insn = NEXT_INSN (ix->ixepilogue_start); - insn != ix->ixepilogue_end; - insn = NEXT_INSN (insn)) - delete_insn (insn); - } - - /* Delete this ixpansion from sublevel_ixpansions. */ - if (previx) - previx->next = ix->next; - else - sublevel_ixpansions.first = ix->next; - if (sublevel_ixpansions.last == ix) - sublevel_ixpansions.last = previx; - } - else - previx = ix; -} - -#ifdef DEBUG_ITERATORS - -/* The functions below are for use from source level debugger. - They print short forms of iterator lists and the iterator stack. */ - -/* Print the name of the iterator D. */ - -void -prdecl (d) - tree d; -{ - if (d) - { - if (TREE_CODE (d) == VAR_DECL) - { - tree tname = DECL_NAME (d); - char *dname = IDENTIFIER_POINTER (tname); - fprintf (stderr, dname); - } - else - fprintf (stderr, "<<?>>"); - } - else - fprintf (stderr, "<<0>>"); -} - -/* Print Iterator List -- names only */ - -tree -pil (head) - tree head; -{ - tree current, next; - for (current = head; current; current = next) - { - tree node = TREE_VALUE (current); - prdecl (node); - next = TREE_CHAIN (current); - if (next) fprintf (stderr, ","); - } - fprintf (stderr, "\n"); -} - -/* Print IXpansion List */ - -struct ixpansion * -pixl (head) - struct ixpansion *head; -{ - struct ixpansion *current, *next; - fprintf (stderr, "> "); - if (head == 0) - fprintf (stderr, "(empty)"); - - for (current=head; current; current = next) - { - tree node = current->ixdecl; - prdecl (node); - next = current->next; - if (next) - fprintf (stderr, ","); - } - fprintf (stderr, "\n"); - return head; -} - -/* Print Iterator Stack. */ - -void -pis () -{ - struct iter_stack_node *stack_node; - - fprintf (stderr, "--SubLevel: "); - pixl (sublevel_ixpansions.first); - fprintf (stderr, "--Stack:--\n"); - for (stack_node = iter_stack; - stack_node; - stack_node = stack_node->next) - pixl (stack_node->first); -} - -#endif /* DEBUG_ITERATORS */ |