| /* Tree lowering pass. This pass gimplifies the tree representation built |
| by the C-based front ends. The structure of gimplified, or |
| language-independent, trees is dictated by the grammar described in this |
| file. |
| Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc. |
| Lowering of expressions contributed by Sebastian Pop <s.pop@laposte.net> |
| Re-written to support lowering of whole function trees, documentation |
| and miscellaneous cleanups by Diego Novillo <dnovillo@redhat.com> |
| |
| 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 |
| version. |
| |
| GCC 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 GCC; see the file COPYING. If not, write to the Free |
| Software Foundation, 59 Temple Place - Suite 330, Boston, MA |
| 02111-1307, USA. */ |
| |
| #include "config.h" |
| #include "system.h" |
| #include "coretypes.h" |
| #include "tm.h" |
| #include "tree.h" |
| #include "errors.h" |
| #include "varray.h" |
| #include "c-tree.h" |
| #include "c-common.h" |
| #include "tree-gimple.h" |
| #include "hard-reg-set.h" |
| #include "basic-block.h" |
| #include "tree-flow.h" |
| #include "tree-inline.h" |
| #include "diagnostic.h" |
| #include "langhooks.h" |
| #include "langhooks-def.h" |
| #include "flags.h" |
| #include "rtl.h" |
| #include "toplev.h" |
| #include "tree-dump.h" |
| #include "c-pretty-print.h" |
| #include "cgraph.h" |
| |
| |
| /* The gimplification pass converts the language-dependent trees |
| (ld-trees) emitted by the parser into language-independent trees |
| (li-trees) that are the target of SSA analysis and transformations. |
| |
| Language-independent trees are based on the SIMPLE intermediate |
| representation used in the McCAT compiler framework: |
| |
| "Designing the McCAT Compiler Based on a Family of Structured |
| Intermediate Representations," |
| L. Hendren, C. Donawa, M. Emami, G. Gao, Justiani, and B. Sridharan, |
| Proceedings of the 5th International Workshop on Languages and |
| Compilers for Parallel Computing, no. 757 in Lecture Notes in |
| Computer Science, New Haven, Connecticut, pp. 406-420, |
| Springer-Verlag, August 3-5, 1992. |
| |
| http://www-acaps.cs.mcgill.ca/info/McCAT/McCAT.html |
| |
| Basically, we walk down gimplifying the nodes that we encounter. As we |
| walk back up, we check that they fit our constraints, and copy them |
| into temporaries if not. */ |
| |
| /* Local declarations. */ |
| |
| enum bc_t { bc_break = 0, bc_continue = 1 }; |
| |
| static struct c_gimplify_ctx |
| { |
| /* For handling break and continue. */ |
| tree current_bc_label; |
| tree bc_id[2]; |
| } *ctxp; |
| |
| static void |
| push_context (void) |
| { |
| gcc_assert (!ctxp); |
| ctxp = (struct c_gimplify_ctx *) xcalloc (1, sizeof (struct c_gimplify_ctx)); |
| ctxp->bc_id[bc_continue] = get_identifier ("continue"); |
| ctxp->bc_id[bc_break] = get_identifier ("break"); |
| } |
| |
| static void |
| pop_context (void) |
| { |
| gcc_assert (ctxp && !ctxp->current_bc_label); |
| free (ctxp); |
| ctxp = NULL; |
| } |
| |
| /* Gimplification of statement trees. */ |
| |
| /* Convert the tree representation of FNDECL from C frontend trees to |
| GENERIC. */ |
| |
| void |
| c_genericize (tree fndecl) |
| { |
| FILE *dump_file; |
| int local_dump_flags; |
| struct cgraph_node *cgn; |
| |
| /* Dump the C-specific tree IR. */ |
| dump_file = dump_begin (TDI_original, &local_dump_flags); |
| if (dump_file) |
| { |
| fprintf (dump_file, "\n;; Function %s", |
| lang_hooks.decl_printable_name (fndecl, 2)); |
| fprintf (dump_file, " (%s)\n", |
| IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (fndecl))); |
| fprintf (dump_file, ";; enabled by -%s\n", dump_flag_name (TDI_original)); |
| fprintf (dump_file, "\n"); |
| |
| if (local_dump_flags & TDF_RAW) |
| dump_node (DECL_SAVED_TREE (fndecl), |
| TDF_SLIM | local_dump_flags, dump_file); |
| else |
| print_c_tree (dump_file, DECL_SAVED_TREE (fndecl)); |
| fprintf (dump_file, "\n"); |
| |
| dump_end (TDI_original, dump_file); |
| } |
| |
| /* Go ahead and gimplify for now. */ |
| push_context (); |
| gimplify_function_tree (fndecl); |
| pop_context (); |
| |
| /* Dump the genericized tree IR. */ |
| dump_function (TDI_generic, fndecl); |
| |
| /* Genericize all nested functions now. We do things in this order so |
| that items like VLA sizes are expanded properly in the context of |
| the correct function. */ |
| cgn = cgraph_node (fndecl); |
| for (cgn = cgn->nested; cgn ; cgn = cgn->next_nested) |
| c_genericize (cgn->decl); |
| } |
| |
| static void |
| add_block_to_enclosing (tree block) |
| { |
| tree enclosing; |
| |
| for (enclosing = gimple_current_bind_expr (); |
| enclosing; enclosing = TREE_CHAIN (enclosing)) |
| if (BIND_EXPR_BLOCK (enclosing)) |
| break; |
| |
| enclosing = BIND_EXPR_BLOCK (enclosing); |
| BLOCK_SUBBLOCKS (enclosing) = chainon (BLOCK_SUBBLOCKS (enclosing), block); |
| } |
| |
| /* Genericize a scope by creating a new BIND_EXPR. |
| BLOCK is either a BLOCK representing the scope or a chain of _DECLs. |
| In the latter case, we need to create a new BLOCK and add it to the |
| BLOCK_SUBBLOCKS of the enclosing block. |
| BODY is a chain of C _STMT nodes for the contents of the scope, to be |
| genericized. */ |
| |
| tree |
| c_build_bind_expr (tree block, tree body) |
| { |
| tree decls, bind; |
| |
| if (block == NULL_TREE) |
| decls = NULL_TREE; |
| else if (TREE_CODE (block) == BLOCK) |
| decls = BLOCK_VARS (block); |
| else |
| { |
| decls = block; |
| if (DECL_ARTIFICIAL (decls)) |
| block = NULL_TREE; |
| else |
| { |
| block = make_node (BLOCK); |
| BLOCK_VARS (block) = decls; |
| add_block_to_enclosing (block); |
| } |
| } |
| |
| if (!body) |
| body = build_empty_stmt (); |
| if (decls || block) |
| { |
| bind = build3 (BIND_EXPR, void_type_node, decls, body, block); |
| TREE_SIDE_EFFECTS (bind) = 1; |
| } |
| else |
| bind = body; |
| |
| return bind; |
| } |
| |
| /* Gimplify an EXPR_STMT node. |
| |
| STMT is the statement node. |
| |
| PRE_P points to the list where side effects that must happen before |
| STMT should be stored. |
| |
| POST_P points to the list where side effects that must happen after |
| STMT should be stored. */ |
| |
| static enum gimplify_status |
| gimplify_expr_stmt (tree *stmt_p) |
| { |
| tree stmt = EXPR_STMT_EXPR (*stmt_p); |
| |
| if (stmt == error_mark_node) |
| stmt = NULL; |
| |
| /* Gimplification of a statement expression will nullify the |
| statement if all its side effects are moved to *PRE_P and *POST_P. |
| |
| In this case we will not want to emit the gimplified statement. |
| However, we may still want to emit a warning, so we do that before |
| gimplification. */ |
| if (stmt && (extra_warnings || warn_unused_value)) |
| { |
| if (!TREE_SIDE_EFFECTS (stmt)) |
| { |
| if (!IS_EMPTY_STMT (stmt) |
| && !VOID_TYPE_P (TREE_TYPE (stmt)) |
| && !TREE_NO_WARNING (stmt)) |
| warning ("statement with no effect"); |
| } |
| else if (warn_unused_value) |
| warn_if_unused_value (stmt, input_location); |
| } |
| |
| if (stmt == NULL_TREE) |
| stmt = alloc_stmt_list (); |
| |
| *stmt_p = stmt; |
| |
| return GS_OK; |
| } |
| |
| /* APPLE LOCAL begin radar 4547045 */ |
| /* Pop label (which should be a 'break' label in this case) from the |
| label of break/continue stack. */ |
| static tree |
| objc_pop_label (void) |
| { |
| tree label = ctxp->current_bc_label; |
| gcc_assert (label); |
| ctxp->current_bc_label = TREE_CHAIN (label); |
| TREE_CHAIN (label) = NULL_TREE; |
| return label; |
| } |
| |
| /* Push the label on break/continue stack of labels. */ |
| static void |
| objc_push_label (tree label) |
| { |
| TREE_CHAIN (label) = ctxp->current_bc_label; |
| ctxp->current_bc_label = label; |
| } |
| /* APPLE LOCAL end radar 4547045 */ |
| |
| /* Begin a scope which can be exited by a break or continue statement. BC |
| indicates which. |
| |
| Just creates a label and pushes it into the current context. */ |
| |
| static tree |
| begin_bc_block (enum bc_t bc) |
| { |
| tree label = create_artificial_label (); |
| DECL_NAME (label) = ctxp->bc_id[bc]; |
| TREE_CHAIN (label) = ctxp->current_bc_label; |
| ctxp->current_bc_label = label; |
| return label; |
| } |
| |
| /* Finish a scope which can be exited by a break or continue statement. |
| LABEL was returned from the most recent call to begin_bc_block. BODY is |
| an expression for the contents of the scope. |
| |
| If we saw a break (or continue) in the scope, append a LABEL_EXPR to |
| body. Otherwise, just forget the label. */ |
| |
| static tree |
| finish_bc_block (tree label, tree body) |
| { |
| gcc_assert (label == ctxp->current_bc_label); |
| |
| if (TREE_USED (label)) |
| { |
| tree t, sl = NULL; |
| |
| /* Clear the name so flow can delete the label. */ |
| DECL_NAME (label) = NULL_TREE; |
| t = build1 (LABEL_EXPR, void_type_node, label); |
| |
| append_to_statement_list (body, &sl); |
| append_to_statement_list (t, &sl); |
| body = sl; |
| } |
| |
| ctxp->current_bc_label = TREE_CHAIN (label); |
| TREE_CHAIN (label) = NULL_TREE; |
| return body; |
| } |
| |
| /* Build a GOTO_EXPR to represent a break or continue statement. BC |
| indicates which. */ |
| |
| static tree |
| build_bc_goto (enum bc_t bc) |
| { |
| tree label; |
| tree target_name = ctxp->bc_id[bc]; |
| |
| /* Look for the appropriate type of label. */ |
| for (label = ctxp->current_bc_label; |
| label; |
| label = TREE_CHAIN (label)) |
| if (DECL_NAME (label) == target_name) |
| break; |
| |
| if (label == NULL_TREE) |
| { |
| if (bc == bc_break) |
| error ("break statement not within loop or switch"); |
| else |
| error ("continue statement not within loop or switch"); |
| |
| return NULL_TREE; |
| } |
| |
| /* Mark the label used for finish_bc_block. */ |
| TREE_USED (label) = 1; |
| return build1 (GOTO_EXPR, void_type_node, label); |
| } |
| |
| /* Build a generic representation of one of the C loop forms. COND is the |
| loop condition or NULL_TREE. BODY is the (possibly compound) statement |
| controlled by the loop. INCR is the increment expression of a for-loop, |
| or NULL_TREE. COND_IS_FIRST indicates whether the condition is |
| evaluated before the loop body as in while and for loops, or after the |
| loop body as in do-while loops. */ |
| |
| /* APPLE LOCAL begin C* language */ |
| static tree |
| gimplify_c_loop (tree cond, tree body, tree incr, bool cond_is_first, |
| tree inner_foreach) |
| { |
| tree top, entry, exit, cont_block, break_block, stmt_list, t; |
| location_t stmt_locus; |
| |
| stmt_locus = input_location; |
| stmt_list = NULL_TREE; |
| entry = NULL_TREE; |
| |
| /* APPLE LOCAL begin radar 4547045 */ |
| /* Order of label addition to stack is important for objc's foreach-stmt. */ |
| /* APPLE LOCAL radar 4667060 */ |
| if (inner_foreach == integer_zero_node) |
| { |
| cont_block = begin_bc_block (bc_continue); |
| break_block = begin_bc_block (bc_break); |
| } |
| else |
| { |
| break_block = begin_bc_block (bc_break); |
| cont_block = begin_bc_block (bc_continue); |
| } |
| /* APPLE LOCAL end radar 4547045 */ |
| |
| /* If condition is zero don't generate a loop construct. */ |
| if (cond && integer_zerop (cond)) |
| { |
| top = NULL_TREE; |
| exit = NULL_TREE; |
| if (cond_is_first) |
| { |
| t = build_bc_goto (bc_break); |
| append_to_statement_list (t, &stmt_list); |
| } |
| } |
| else |
| { |
| /* If we use a LOOP_EXPR here, we have to feed the whole thing |
| back through the main gimplifier to lower it. Given that we |
| have to gimplify the loop body NOW so that we can resolve |
| break/continue stmts, seems easier to just expand to gotos. */ |
| top = build1 (LABEL_EXPR, void_type_node, NULL_TREE); |
| |
| /* If we have an exit condition, then we build an IF with gotos either |
| out of the loop, or to the top of it. If there's no exit condition, |
| then we just build a jump back to the top. */ |
| exit = build_and_jump (&LABEL_EXPR_LABEL (top)); |
| if (cond && !integer_nonzerop (cond)) |
| { |
| /* APPLE LOCAL begin radar 4667060 */ |
| bool outer_foreach_loop = (inner_foreach |
| && inner_foreach != integer_zero_node); |
| tree label = NULL_TREE; |
| if (outer_foreach_loop) |
| /* New spec. requires that if no match was found; i.e. foreach |
| exited with no match, 'elem' be set to nil. So, we use a new |
| label for getting out of of the outer while loop and set |
| 'elem=nill' after this label. */ |
| t = build_and_jump (&label); |
| else |
| t = build_bc_goto (bc_break); |
| exit = build3 (COND_EXPR, void_type_node, cond, exit, t); |
| exit = fold (exit); |
| gimplify_stmt (&exit); |
| if (outer_foreach_loop) |
| { |
| /* Label: ; */ |
| t = build1 (LABEL_EXPR, void_type_node, label); |
| gimplify_stmt (&t); |
| append_to_statement_list (t, &exit); |
| /* elem = nil */ |
| t = build (MODIFY_EXPR, void_type_node, inner_foreach, |
| fold_convert (TREE_TYPE (inner_foreach), |
| integer_zero_node)); |
| gimplify_stmt (&t); |
| append_to_statement_list (t, &exit); |
| } |
| /* APPLE LOCAL end radar 4667060 */ |
| if (cond_is_first) |
| { |
| if (incr) |
| { |
| entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE); |
| t = build_and_jump (&LABEL_EXPR_LABEL (entry)); |
| } |
| else |
| t = build_bc_goto (bc_continue); |
| append_to_statement_list (t, &stmt_list); |
| } |
| } |
| } |
| |
| /* APPLE LOCAL begin radar 4547045 */ |
| /* Pop foreach's inner loop break label so outer loop's |
| break label becomes target of inner loop body's break statements. |
| */ |
| t = NULL_TREE; |
| /* APPLE LOCAL radar 4667060 */ |
| if (inner_foreach == integer_zero_node) |
| t = objc_pop_label (); |
| /* APPLE LOCAL end radar 4547045 */ |
| gimplify_stmt (&body); |
| gimplify_stmt (&incr); |
| |
| body = finish_bc_block (cont_block, body); |
| /* APPLE LOCAL begin radar 4547045 */ |
| /* Push back inner loop's own 'break' label so rest |
| of code works seemlessly. */ |
| /* APPLE LOCAL radar 4667060 */ |
| if (inner_foreach == integer_zero_node) |
| objc_push_label (t); |
| /* APPLE LOCAL end radar 4547045 */ |
| |
| append_to_statement_list (top, &stmt_list); |
| append_to_statement_list (body, &stmt_list); |
| append_to_statement_list (incr, &stmt_list); |
| append_to_statement_list (entry, &stmt_list); |
| append_to_statement_list (exit, &stmt_list); |
| |
| annotate_all_with_locus (&stmt_list, stmt_locus); |
| |
| return finish_bc_block (break_block, stmt_list); |
| } |
| /* APPLE LOCAL end C* language */ |
| |
| /* Gimplify a FOR_STMT node. Move the stuff in the for-init-stmt into the |
| prequeue and hand off to gimplify_c_loop. */ |
| |
| static enum gimplify_status |
| gimplify_for_stmt (tree *stmt_p, tree *pre_p) |
| { |
| tree stmt = *stmt_p; |
| |
| if (FOR_INIT_STMT (stmt)) |
| gimplify_and_add (FOR_INIT_STMT (stmt), pre_p); |
| |
| *stmt_p = gimplify_c_loop (FOR_COND (stmt), FOR_BODY (stmt), |
| /* APPLE LOCAL C* language */ |
| FOR_EXPR (stmt), 1, NULL_TREE); |
| |
| return GS_ALL_DONE; |
| } |
| |
| /* Gimplify a WHILE_STMT node. */ |
| |
| static enum gimplify_status |
| gimplify_while_stmt (tree *stmt_p) |
| { |
| tree stmt = *stmt_p; |
| *stmt_p = gimplify_c_loop (WHILE_COND (stmt), WHILE_BODY (stmt), |
| /* APPLE LOCAL C* language */ |
| NULL_TREE, 1, NULL_TREE); |
| return GS_ALL_DONE; |
| } |
| |
| /* Gimplify a DO_STMT node. */ |
| |
| static enum gimplify_status |
| gimplify_do_stmt (tree *stmt_p) |
| { |
| tree stmt = *stmt_p; |
| |
| /* APPLE LOCAL begin llvm */ |
| #ifndef ENABLE_LLVM |
| *stmt_p = gimplify_c_loop (DO_COND (stmt), DO_BODY (stmt), |
| /* APPLE LOCAL C* language */ |
| NULL_TREE, 0, DO_FOREACH (stmt)); |
| #else |
| *stmt_p = gimplify_c_loop (DO_COND (stmt), DO_BODY (stmt), |
| /* APPLE LOCAL C* language */ |
| NULL_TREE, 0, NULL_TREE); |
| #endif |
| /* APPLE LOCAL end llvm */ |
| return GS_ALL_DONE; |
| } |
| |
| /* Genericize a SWITCH_STMT by turning it into a SWITCH_EXPR. */ |
| |
| static enum gimplify_status |
| gimplify_switch_stmt (tree *stmt_p) |
| { |
| tree stmt = *stmt_p; |
| tree break_block, body; |
| location_t stmt_locus = input_location; |
| |
| break_block = begin_bc_block (bc_break); |
| |
| body = SWITCH_STMT_BODY (stmt); |
| if (!body) |
| body = build_empty_stmt (); |
| |
| *stmt_p = build3 (SWITCH_EXPR, SWITCH_STMT_TYPE (stmt), |
| SWITCH_STMT_COND (stmt), body, NULL_TREE); |
| SET_EXPR_LOCATION (*stmt_p, stmt_locus); |
| gimplify_stmt (stmt_p); |
| |
| *stmt_p = finish_bc_block (break_block, *stmt_p); |
| return GS_ALL_DONE; |
| } |
| |
| /* Gimplification of expression trees. */ |
| |
| /* Gimplify a C99 compound literal expression. This just means adding the |
| DECL_EXPR before the current EXPR_STMT and using its anonymous decl |
| instead. */ |
| |
| static enum gimplify_status |
| gimplify_compound_literal_expr (tree *expr_p, tree *pre_p) |
| { |
| tree decl_s = COMPOUND_LITERAL_EXPR_DECL_STMT (*expr_p); |
| tree decl = DECL_EXPR_DECL (decl_s); |
| |
| /* This decl isn't mentioned in the enclosing block, so add it to the |
| list of temps. FIXME it seems a bit of a kludge to say that |
| anonymous artificial vars aren't pushed, but everything else is. */ |
| /* APPLE LOCAL file mainline 4.0.4 08-25-2006 4647057 */ |
| if (DECL_NAME (decl) == NULL_TREE && !DECL_SEEN_IN_BIND_EXPR_P (decl)) |
| gimple_add_tmp_var (decl); |
| |
| gimplify_and_add (decl_s, pre_p); |
| *expr_p = decl; |
| return GS_OK; |
| } |
| |
| /* Do C-specific gimplification. Args are as for gimplify_expr. */ |
| |
| int |
| c_gimplify_expr (tree *expr_p, tree *pre_p, tree *post_p ATTRIBUTE_UNUSED) |
| { |
| enum tree_code code = TREE_CODE (*expr_p); |
| |
| switch (code) |
| { |
| case DECL_EXPR: |
| /* This is handled mostly by gimplify.c, but we have to deal with |
| not warning about int x = x; as it is a GCC extension to turn off |
| this warning but only if warn_init_self is zero. */ |
| if (TREE_CODE (DECL_EXPR_DECL (*expr_p)) == VAR_DECL |
| && !DECL_EXTERNAL (DECL_EXPR_DECL (*expr_p)) |
| && !TREE_STATIC (DECL_EXPR_DECL (*expr_p)) |
| && (DECL_INITIAL (DECL_EXPR_DECL (*expr_p)) |
| == DECL_EXPR_DECL (*expr_p)) |
| && !warn_init_self) |
| TREE_NO_WARNING (DECL_EXPR_DECL (*expr_p)) = 1; |
| return GS_UNHANDLED; |
| |
| case COMPOUND_LITERAL_EXPR: |
| return gimplify_compound_literal_expr (expr_p, pre_p); |
| |
| case FOR_STMT: |
| return gimplify_for_stmt (expr_p, pre_p); |
| |
| case WHILE_STMT: |
| return gimplify_while_stmt (expr_p); |
| |
| case DO_STMT: |
| return gimplify_do_stmt (expr_p); |
| |
| case SWITCH_STMT: |
| return gimplify_switch_stmt (expr_p); |
| |
| case EXPR_STMT: |
| return gimplify_expr_stmt (expr_p); |
| |
| case CONTINUE_STMT: |
| *expr_p = build_bc_goto (bc_continue); |
| return GS_ALL_DONE; |
| |
| case BREAK_STMT: |
| *expr_p = build_bc_goto (bc_break); |
| return GS_ALL_DONE; |
| |
| default: |
| return GS_UNHANDLED; |
| } |
| } |