/* This file contains the definitions and documentation for the common tree codes used in the GNU C and C++ compilers (see c-common.def for the standard codes). Copyright (C) 2000, 2001, 2002, 2003 Free Software Foundation, Inc. Written by Benjamin Chelf (chelf@codesourcery.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 "function.h" #include "splay-tree.h" #include "varray.h" #include "c-common.h" #include "except.h" #include "toplev.h" #include "flags.h" #include "ggc.h" #include "rtl.h" #include "expr.h" #include "output.h" #include "timevar.h" #include "predict.h" /* If non-NULL, the address of a language-specific function for expanding statements. */ void (*lang_expand_stmt) PARAMS ((tree)); /* If non-NULL, the address of a language-specific function for expanding a DECL_STMT. After the language-independent cases are handled, this function will be called. If this function is not defined, it is assumed that declarations other than those for variables and labels do not require any RTL generation. */ void (*lang_expand_decl_stmt) PARAMS ((tree)); /* Create an empty statement tree rooted at T. */ void begin_stmt_tree (t) tree *t; { /* We create a trivial EXPR_STMT so that last_tree is never NULL in what follows. We remove the extraneous statement in finish_stmt_tree. */ *t = build_nt (EXPR_STMT, void_zero_node); last_tree = *t; last_expr_type = NULL_TREE; last_expr_filename = input_filename; } /* T is a statement. Add it to the statement-tree. */ tree add_stmt (t) tree t; { if (input_filename != last_expr_filename) { /* If the filename has changed, also add in a FILE_STMT. Do a string compare first, though, as it might be an equivalent string. */ int add = (strcmp (input_filename, last_expr_filename) != 0); last_expr_filename = input_filename; if (add) { tree pos = build_nt (FILE_STMT, get_identifier (input_filename)); add_stmt (pos); } } /* Add T to the statement-tree. */ TREE_CHAIN (last_tree) = t; last_tree = t; /* When we expand a statement-tree, we must know whether or not the statements are full-expressions. We record that fact here. */ STMT_IS_FULL_EXPR_P (last_tree) = stmts_are_full_exprs_p (); /* Keep track of the number of statements in this function. */ if (current_function_decl) ++DECL_NUM_STMTS (current_function_decl); return t; } /* Create a declaration statement for the declaration given by the DECL. */ void add_decl_stmt (decl) tree decl; { tree decl_stmt; /* We need the type to last until instantiation time. */ decl_stmt = build_stmt (DECL_STMT, decl); add_stmt (decl_stmt); } /* Add a scope-statement to the statement-tree. BEGIN_P indicates whether this statements opens or closes a scope. PARTIAL_P is true for a partial scope, i.e, the scope that begins after a label when an object that needs a cleanup is created. If BEGIN_P is nonzero, returns a new TREE_LIST representing the top of the SCOPE_STMT stack. The TREE_PURPOSE is the new SCOPE_STMT. If BEGIN_P is zero, returns a TREE_LIST whose TREE_VALUE is the new SCOPE_STMT, and whose TREE_PURPOSE is the matching SCOPE_STMT with SCOPE_BEGIN_P set. */ tree add_scope_stmt (begin_p, partial_p) int begin_p; int partial_p; { tree *stack_ptr = current_scope_stmt_stack (); tree ss; tree top = *stack_ptr; /* Build the statement. */ ss = build_stmt (SCOPE_STMT, NULL_TREE); SCOPE_BEGIN_P (ss) = begin_p; SCOPE_PARTIAL_P (ss) = partial_p; /* Keep the scope stack up to date. */ if (begin_p) { top = tree_cons (ss, NULL_TREE, top); *stack_ptr = top; } else { if (partial_p != SCOPE_PARTIAL_P (TREE_PURPOSE (top))) abort (); TREE_VALUE (top) = ss; *stack_ptr = TREE_CHAIN (top); } /* Add the new statement to the statement-tree. */ add_stmt (ss); return top; } /* Finish the statement tree rooted at T. */ void finish_stmt_tree (t) tree *t; { tree stmt; /* Remove the fake extra statement added in begin_stmt_tree. */ stmt = TREE_CHAIN (*t); *t = stmt; last_tree = NULL_TREE; if (cfun && stmt) { /* The line-number recorded in the outermost statement in a function is the line number of the end of the function. */ STMT_LINENO (stmt) = lineno; STMT_LINENO_FOR_FN_P (stmt) = 1; } } /* Build a generic statement based on the given type of node and arguments. Similar to `build_nt', except that we set STMT_LINENO to be the current line number. */ /* ??? This should be obsolete with the lineno_stmt productions in the grammar. */ tree build_stmt VPARAMS ((enum tree_code code, ...)) { tree t; int length; int i; VA_OPEN (p, code); VA_FIXEDARG (p, enum tree_code, code); t = make_node (code); length = TREE_CODE_LENGTH (code); STMT_LINENO (t) = lineno; for (i = 0; i < length; i++) TREE_OPERAND (t, i) = va_arg (p, tree); VA_CLOSE (p); return t; } /* Some statements, like for-statements or if-statements, require a condition. This condition can be a declaration. If T is such a declaration it is processed, and an expression appropriate to use as the condition is returned. Otherwise, T itself is returned. */ tree expand_cond (t) tree t; { if (t && TREE_CODE (t) == TREE_LIST) { expand_stmt (TREE_PURPOSE (t)); return TREE_VALUE (t); } else return t; } /* Create RTL for the local static variable DECL. */ void make_rtl_for_local_static (decl) tree decl; { const char *asmspec = NULL; /* If we inlined this variable, we could see it's declaration again. */ if (TREE_ASM_WRITTEN (decl)) return; /* If the DECL_ASSEMBLER_NAME is not the same as the DECL_NAME, then either we already created RTL for this DECL (and since it was a local variable, its DECL_ASSEMBLER_NAME got hacked up to prevent clashes with other local statics with the same name by a previous call to make_decl_rtl), or the user explicitly requested a particular assembly name for this variable, using the GNU extension for this purpose: int i asm ("j"); There's no way to know which case we're in, here. But, it turns out we're safe. If there's already RTL, then rest_of_decl_compilation ignores the ASMSPEC parameter, so we may as well not pass it in. If there isn't RTL, then we didn't already create RTL, which means that the modification to DECL_ASSEMBLER_NAME came only via the explicit extension. */ if (DECL_ASSEMBLER_NAME (decl) != DECL_NAME (decl) && !DECL_RTL_SET_P (decl)) asmspec = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl)); rest_of_decl_compilation (decl, asmspec, /*top_level=*/0, /*at_end=*/0); } /* Let the back-end know about DECL. */ void emit_local_var (decl) tree decl; { /* Create RTL for this variable. */ if (!DECL_RTL_SET_P (decl)) { if (DECL_C_HARD_REGISTER (decl)) /* The user specified an assembler name for this variable. Set that up now. */ rest_of_decl_compilation (decl, IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl)), /*top_level=*/0, /*at_end=*/0); else expand_decl (decl); } /* Actually do the initialization. */ if (stmts_are_full_exprs_p ()) expand_start_target_temps (); expand_decl_init (decl); if (stmts_are_full_exprs_p ()) expand_end_target_temps (); } /* Helper for generating the RTL at the beginning of a scope. */ void genrtl_do_pushlevel () { emit_line_note (input_filename, lineno); clear_last_expr (); } /* Generate the RTL for DESTINATION, which is a GOTO_STMT. */ void genrtl_goto_stmt (destination) tree destination; { if (TREE_CODE (destination) == IDENTIFIER_NODE) abort (); /* We warn about unused labels with -Wunused. That means we have to mark the used labels as used. */ if (TREE_CODE (destination) == LABEL_DECL) TREE_USED (destination) = 1; emit_line_note (input_filename, lineno); if (TREE_CODE (destination) == LABEL_DECL) { label_rtx (destination); expand_goto (destination); } else expand_computed_goto (destination); } /* Generate the RTL for EXPR, which is an EXPR_STMT. Provided just for backward compatibility. genrtl_expr_stmt_value() should be used for new code. */ void genrtl_expr_stmt (expr) tree expr; { genrtl_expr_stmt_value (expr, -1, 1); } /* Generate the RTL for EXPR, which is an EXPR_STMT. WANT_VALUE tells whether to (1) save the value of the expression, (0) discard it or (-1) use expr_stmts_for_value to tell. The use of -1 is deprecated, and retained only for backward compatibility. MAYBE_LAST is nonzero if this EXPR_STMT might be the last statement in expression statement. */ void genrtl_expr_stmt_value (expr, want_value, maybe_last) tree expr; int want_value, maybe_last; { if (expr != NULL_TREE) { emit_line_note (input_filename, lineno); if (stmts_are_full_exprs_p ()) expand_start_target_temps (); if (expr != error_mark_node) expand_expr_stmt_value (expr, want_value, maybe_last); if (stmts_are_full_exprs_p ()) expand_end_target_temps (); } } /* Generate the RTL for T, which is a DECL_STMT. */ void genrtl_decl_stmt (t) tree t; { tree decl; emit_line_note (input_filename, lineno); decl = DECL_STMT_DECL (t); /* If this is a declaration for an automatic local variable, initialize it. Note that we might also see a declaration for a namespace-scope object (declared with `extern'). We don't have to handle the initialization of those objects here; they can only be declarations, rather than definitions. */ if (TREE_CODE (decl) == VAR_DECL && !TREE_STATIC (decl) && !DECL_EXTERNAL (decl)) { /* Let the back-end know about this variable. */ if (!anon_aggr_type_p (TREE_TYPE (decl))) emit_local_var (decl); else expand_anon_union_decl (decl, NULL_TREE, DECL_ANON_UNION_ELEMS (decl)); } else if (TREE_CODE (decl) == VAR_DECL && TREE_STATIC (decl)) make_rtl_for_local_static (decl); else if (TREE_CODE (decl) == LABEL_DECL && C_DECLARED_LABEL_FLAG (decl)) declare_nonlocal_label (decl); else if (lang_expand_decl_stmt) (*lang_expand_decl_stmt) (t); } /* Generate the RTL for T, which is an IF_STMT. */ void genrtl_if_stmt (t) tree t; { tree cond; genrtl_do_pushlevel (); cond = expand_cond (IF_COND (t)); emit_line_note (input_filename, lineno); expand_start_cond (cond, 0); if (THEN_CLAUSE (t)) expand_stmt (THEN_CLAUSE (t)); if (ELSE_CLAUSE (t)) { expand_start_else (); expand_stmt (ELSE_CLAUSE (t)); } expand_end_cond (); } /* Generate the RTL for T, which is a WHILE_STMT. */ void genrtl_while_stmt (t) tree t; { tree cond = WHILE_COND (t); emit_nop (); emit_line_note (input_filename, lineno); expand_start_loop (1); genrtl_do_pushlevel (); if (cond && !integer_nonzerop (cond)) { cond = expand_cond (cond); emit_line_note (input_filename, lineno); expand_exit_loop_top_cond (0, cond); genrtl_do_pushlevel (); } expand_stmt (WHILE_BODY (t)); expand_end_loop (); } /* Generate the RTL for T, which is a DO_STMT. */ void genrtl_do_stmt (t) tree t; { tree cond = DO_COND (t); /* Recognize the common special-case of do { ... } while (0) and do not emit the loop widgetry in this case. In particular this avoids cluttering the rtl with dummy loop notes, which can affect alignment of adjacent labels. COND can be NULL due to parse errors. */ if (!cond || integer_zerop (cond)) { expand_start_null_loop (); expand_stmt (DO_BODY (t)); expand_end_null_loop (); } else if (integer_nonzerop (cond)) { emit_nop (); emit_line_note (input_filename, lineno); expand_start_loop (1); expand_stmt (DO_BODY (t)); emit_line_note (input_filename, lineno); expand_end_loop (); } else { emit_nop (); emit_line_note (input_filename, lineno); expand_start_loop_continue_elsewhere (1); expand_stmt (DO_BODY (t)); expand_loop_continue_here (); cond = expand_cond (cond); emit_line_note (input_filename, lineno); expand_exit_loop_if_false (0, cond); expand_end_loop (); } } /* Build the node for a return statement and return it. */ tree build_return_stmt (expr) tree expr; { return (build_stmt (RETURN_STMT, expr)); } /* Generate the RTL for STMT, which is a RETURN_STMT. */ void genrtl_return_stmt (stmt) tree stmt; { tree expr; expr = RETURN_STMT_EXPR (stmt); emit_line_note (input_filename, lineno); if (!expr) expand_null_return (); else { expand_start_target_temps (); expand_return (expr); expand_end_target_temps (); } } /* Generate the RTL for T, which is a FOR_STMT. */ void genrtl_for_stmt (t) tree t; { tree cond = FOR_COND (t); const char *saved_filename; int saved_lineno; if (NEW_FOR_SCOPE_P (t)) genrtl_do_pushlevel (); expand_stmt (FOR_INIT_STMT (t)); /* Expand the initialization. */ emit_nop (); emit_line_note (input_filename, lineno); if (FOR_EXPR (t)) expand_start_loop_continue_elsewhere (1); else expand_start_loop (1); genrtl_do_pushlevel (); /* Save the filename and line number so that we expand the FOR_EXPR we can reset them back to the saved values. */ saved_filename = input_filename; saved_lineno = lineno; /* Expand the condition. */ if (cond && !integer_nonzerop (cond)) { cond = expand_cond (cond); emit_line_note (input_filename, lineno); expand_exit_loop_top_cond (0, cond); genrtl_do_pushlevel (); } /* Expand the body. */ expand_stmt (FOR_BODY (t)); /* Expand the increment expression. */ input_filename = saved_filename; lineno = saved_lineno; emit_line_note (input_filename, lineno); if (FOR_EXPR (t)) { expand_loop_continue_here (); genrtl_expr_stmt (FOR_EXPR (t)); } expand_end_loop (); } /* Build a break statement node and return it. */ tree build_break_stmt () { return (build_stmt (BREAK_STMT)); } /* Generate the RTL for a BREAK_STMT. */ void genrtl_break_stmt () { emit_line_note (input_filename, lineno); if ( ! expand_exit_something ()) error ("break statement not within loop or switch"); } /* Build a continue statement node and return it. */ tree build_continue_stmt () { return (build_stmt (CONTINUE_STMT)); } /* Generate the RTL for a CONTINUE_STMT. */ void genrtl_continue_stmt () { emit_line_note (input_filename, lineno); if (! expand_continue_loop (0)) error ("continue statement not within a loop"); } /* Generate the RTL for T, which is a SCOPE_STMT. */ void genrtl_scope_stmt (t) tree t; { tree block = SCOPE_STMT_BLOCK (t); if (!SCOPE_NO_CLEANUPS_P (t)) { if (SCOPE_BEGIN_P (t)) expand_start_bindings_and_block (2 * SCOPE_NULLIFIED_P (t), block); else if (SCOPE_END_P (t)) expand_end_bindings (NULL_TREE, !SCOPE_NULLIFIED_P (t), 0); } else if (!SCOPE_NULLIFIED_P (t)) { rtx note = emit_note (NULL, (SCOPE_BEGIN_P (t) ? NOTE_INSN_BLOCK_BEG : NOTE_INSN_BLOCK_END)); NOTE_BLOCK (note) = block; } /* If we're at the end of a scope that contains inlined nested functions, we have to decide whether or not to write them out. */ if (block && SCOPE_END_P (t)) { tree fn; for (fn = BLOCK_VARS (block); fn; fn = TREE_CHAIN (fn)) { if (TREE_CODE (fn) == FUNCTION_DECL && DECL_CONTEXT (fn) == current_function_decl && DECL_SAVED_INSNS (fn) && !TREE_ASM_WRITTEN (fn) && TREE_ADDRESSABLE (fn)) { push_function_context (); output_inline_function (fn); pop_function_context (); } } } } /* Generate the RTL for T, which is a SWITCH_STMT. */ void genrtl_switch_stmt (t) tree t; { tree cond; genrtl_do_pushlevel (); cond = expand_cond (SWITCH_COND (t)); if (cond == error_mark_node) /* The code is in error, but we don't want expand_end_case to crash. */ cond = boolean_false_node; emit_line_note (input_filename, lineno); expand_start_case (1, cond, TREE_TYPE (cond), "switch statement"); expand_stmt (SWITCH_BODY (t)); expand_end_case_type (cond, SWITCH_TYPE (t)); } /* Create a CASE_LABEL tree node and return it. */ tree build_case_label (low_value, high_value, label_decl) tree low_value; tree high_value; tree label_decl; { return build_stmt (CASE_LABEL, low_value, high_value, label_decl); } /* Generate the RTL for a CASE_LABEL. */ void genrtl_case_label (case_label) tree case_label; { tree duplicate; tree cleanup; cleanup = last_cleanup_this_contour (); if (cleanup) { static int explained = 0; warning ("destructor needed for `%#D'", (TREE_PURPOSE (cleanup))); warning ("where case label appears here"); if (!explained) { warning ("(enclose actions of previous case statements requiring destructors in their own scope.)"); explained = 1; } } add_case_node (CASE_LOW (case_label), CASE_HIGH (case_label), CASE_LABEL_DECL (case_label), &duplicate); } /* Generate the RTL for T, which is a COMPOUND_STMT. */ void genrtl_compound_stmt (t) tree t; { #ifdef ENABLE_CHECKING struct nesting *n = current_nesting_level (); #endif expand_stmt (COMPOUND_BODY (t)); #ifdef ENABLE_CHECKING /* Make sure that we've pushed and popped the same number of levels. */ if (!COMPOUND_STMT_NO_SCOPE (t) && n != current_nesting_level ()) abort (); #endif } /* Generate the RTL for an ASM_STMT. */ void genrtl_asm_stmt (cv_qualifier, string, output_operands, input_operands, clobbers, asm_input_p) tree cv_qualifier; tree string; tree output_operands; tree input_operands; tree clobbers; int asm_input_p; { if (cv_qualifier != NULL_TREE && cv_qualifier != ridpointers[(int) RID_VOLATILE]) { warning ("%s qualifier ignored on asm", IDENTIFIER_POINTER (cv_qualifier)); cv_qualifier = NULL_TREE; } emit_line_note (input_filename, lineno); if (asm_input_p) expand_asm (string, cv_qualifier != NULL_TREE); else c_expand_asm_operands (string, output_operands, input_operands, clobbers, cv_qualifier != NULL_TREE, input_filename, lineno); } /* Generate the RTL for a DECL_CLEANUP. */ void genrtl_decl_cleanup (t) tree t; { tree decl = CLEANUP_DECL (t); if (!decl || (DECL_SIZE (decl) && TREE_TYPE (decl) != error_mark_node)) expand_decl_cleanup_eh (decl, CLEANUP_EXPR (t), CLEANUP_EH_ONLY (t)); } /* We're about to expand T, a statement. Set up appropriate context for the substitution. */ void prep_stmt (t) tree t; { if (!STMT_LINENO_FOR_FN_P (t)) lineno = STMT_LINENO (t); current_stmt_tree ()->stmts_are_full_exprs_p = STMT_IS_FULL_EXPR_P (t); } /* Generate the RTL for the statement T, its substatements, and any other statements at its nesting level. */ void expand_stmt (t) tree t; { while (t && t != error_mark_node) { int saved_stmts_are_full_exprs_p; /* Set up context appropriately for handling this statement. */ saved_stmts_are_full_exprs_p = stmts_are_full_exprs_p (); prep_stmt (t); switch (TREE_CODE (t)) { case FILE_STMT: input_filename = FILE_STMT_FILENAME (t); break; case RETURN_STMT: genrtl_return_stmt (t); break; case EXPR_STMT: genrtl_expr_stmt_value (EXPR_STMT_EXPR (t), TREE_ADDRESSABLE (t), TREE_CHAIN (t) == NULL || (TREE_CODE (TREE_CHAIN (t)) == SCOPE_STMT && TREE_CHAIN (TREE_CHAIN (t)) == NULL)); break; case DECL_STMT: genrtl_decl_stmt (t); break; case FOR_STMT: genrtl_for_stmt (t); break; case WHILE_STMT: genrtl_while_stmt (t); break; case DO_STMT: genrtl_do_stmt (t); break; case IF_STMT: genrtl_if_stmt (t); break; case COMPOUND_STMT: genrtl_compound_stmt (t); break; case BREAK_STMT: genrtl_break_stmt (); break; case CONTINUE_STMT: genrtl_continue_stmt (); break; case SWITCH_STMT: genrtl_switch_stmt (t); break; case CASE_LABEL: genrtl_case_label (t); break; case LABEL_STMT: expand_label (LABEL_STMT_LABEL (t)); break; case GOTO_STMT: /* Emit information for branch prediction. */ if (!GOTO_FAKE_P (t) && TREE_CODE (GOTO_DESTINATION (t)) == LABEL_DECL && flag_guess_branch_prob) { rtx note = emit_note (NULL, NOTE_INSN_PREDICTION); NOTE_PREDICTION (note) = NOTE_PREDICT (PRED_GOTO, NOT_TAKEN); } genrtl_goto_stmt (GOTO_DESTINATION (t)); break; case ASM_STMT: genrtl_asm_stmt (ASM_CV_QUAL (t), ASM_STRING (t), ASM_OUTPUTS (t), ASM_INPUTS (t), ASM_CLOBBERS (t), ASM_INPUT_P (t)); break; case SCOPE_STMT: genrtl_scope_stmt (t); break; case CLEANUP_STMT: genrtl_decl_cleanup (t); break; default: if (lang_expand_stmt) (*lang_expand_stmt) (t); else abort (); break; } /* Restore saved state. */ current_stmt_tree ()->stmts_are_full_exprs_p = saved_stmts_are_full_exprs_p; /* Go on to the next statement in this scope. */ t = TREE_CHAIN (t); } }