/* Subroutines shared by all languages that are variants of C. Copyright (C) 1992, 93-99, 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. */ #include "config.h" #include "system.h" #include "tree.h" #include "c-lex.h" #include "c-tree.h" #include "flags.h" #include "obstack.h" #include "toplev.h" #include "output.h" #include "c-pragma.h" #include "rtl.h" #if USE_CPPLIB #include "cpplib.h" cpp_reader parse_in; cpp_options parse_options; static enum cpp_token cpp_token; #endif #ifndef WCHAR_TYPE_SIZE #ifdef INT_TYPE_SIZE #define WCHAR_TYPE_SIZE INT_TYPE_SIZE #else #define WCHAR_TYPE_SIZE BITS_PER_WORD #endif #endif extern struct obstack permanent_obstack; /* Nonzero means the expression being parsed will never be evaluated. This is a count, since unevaluated expressions can nest. */ int skip_evaluation; enum attrs {A_PACKED, A_NOCOMMON, A_COMMON, A_NORETURN, A_CONST, A_T_UNION, A_NO_CHECK_MEMORY_USAGE, A_NO_INSTRUMENT_FUNCTION, A_CONSTRUCTOR, A_DESTRUCTOR, A_MODE, A_SECTION, A_ALIGNED, A_UNUSED, A_FORMAT, A_FORMAT_ARG, A_WEAK, A_ALIAS, A_NONNULL, A_SENTINEL }; enum format_type { printf_format_type, scanf_format_type, strftime_format_type }; static void declare_hidden_char_array PROTO((const char *, const char *)); static void add_attribute PROTO((enum attrs, const char *, int, int, int)); static void init_attributes PROTO((void)); static tree c_find_base_decl PROTO((tree)); static int default_valid_lang_attribute PROTO ((tree, tree, tree, tree)); /* Keep a stack of if statements. We record the number of compound statements seen up to the if keyword, as well as the line number and file of the if. If a potentially ambiguous else is seen, that fact is recorded; the warning is issued when we can be sure that the enclosing if statement does not have an else branch. */ typedef struct { int compstmt_count; int line; const char *file; int needs_warning; } if_elt; static void tfaff PROTO((void)); static if_elt *if_stack; /* Amount of space in the if statement stack. */ static int if_stack_space = 0; /* Stack pointer. */ static int if_stack_pointer = 0; /* Generate RTL for the start of an if-then, and record the start of it for ambiguous else detection. */ void c_expand_start_cond (cond, exitflag, compstmt_count) tree cond; int exitflag; int compstmt_count; { /* Make sure there is enough space on the stack. */ if (if_stack_space == 0) { if_stack_space = 10; if_stack = (if_elt *)xmalloc (10 * sizeof (if_elt)); } else if (if_stack_space == if_stack_pointer) { if_stack_space += 10; if_stack = (if_elt *)xrealloc (if_stack, if_stack_space * sizeof (if_elt)); } /* Record this if statement. */ if_stack[if_stack_pointer].compstmt_count = compstmt_count; if_stack[if_stack_pointer].file = input_filename; if_stack[if_stack_pointer].line = lineno; if_stack[if_stack_pointer].needs_warning = 0; if_stack_pointer++; expand_start_cond (cond, exitflag); } /* Generate RTL for the end of an if-then. Optionally warn if a nested if statement had an ambiguous else clause. */ void c_expand_end_cond () { if_stack_pointer--; if (if_stack[if_stack_pointer].needs_warning) warning_with_file_and_line (if_stack[if_stack_pointer].file, if_stack[if_stack_pointer].line, "suggest explicit braces to avoid ambiguous `else'"); expand_end_cond (); } /* Generate RTL between the then-clause and the else-clause of an if-then-else. */ void c_expand_start_else () { /* An ambiguous else warning must be generated for the enclosing if statement, unless we see an else branch for that one, too. */ if (warn_parentheses && if_stack_pointer > 1 && (if_stack[if_stack_pointer - 1].compstmt_count == if_stack[if_stack_pointer - 2].compstmt_count)) if_stack[if_stack_pointer - 2].needs_warning = 1; /* Even if a nested if statement had an else branch, it can't be ambiguous if this one also has an else. So don't warn in that case. Also don't warn for any if statements nested in this else. */ if_stack[if_stack_pointer - 1].needs_warning = 0; if_stack[if_stack_pointer - 1].compstmt_count--; expand_start_else (); } /* Make bindings for __FUNCTION__, __PRETTY_FUNCTION__, and __func__. */ void declare_function_name () { const char *name, *printable_name; if (current_function_decl == NULL) { name = ""; printable_name = "top level"; } else { /* Allow functions to be nameless (such as artificial ones). */ if (DECL_NAME (current_function_decl)) name = IDENTIFIER_POINTER (DECL_NAME (current_function_decl)); else name = ""; printable_name = (*decl_printable_name) (current_function_decl, 2); } declare_hidden_char_array ("__FUNCTION__", name); declare_hidden_char_array ("__PRETTY_FUNCTION__", printable_name); /* The ISO C people "of course" couldn't use __FUNCTION__ in the ISO C 9x standard; instead a new variable is invented. */ declare_hidden_char_array ("__func__", name); } static void declare_hidden_char_array (name, value) const char *name, *value; { tree decl, type, init; int vlen; /* If the default size of char arrays isn't big enough for the name, or if we want to give warnings for large objects, make a bigger one. */ vlen = strlen (value) + 1; type = char_array_type_node; if (TREE_INT_CST_LOW (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) < vlen || warn_larger_than) type = build_array_type (char_type_node, build_index_type (build_int_2 (vlen, 0))); push_obstacks_nochange (); decl = build_decl (VAR_DECL, get_identifier (name), type); TREE_STATIC (decl) = 1; TREE_READONLY (decl) = 1; TREE_ASM_WRITTEN (decl) = 1; DECL_SOURCE_LINE (decl) = 0; DECL_ARTIFICIAL (decl) = 1; DECL_IN_SYSTEM_HEADER (decl) = 1; DECL_IGNORED_P (decl) = 1; init = build_string (vlen, value); TREE_TYPE (init) = type; DECL_INITIAL (decl) = init; finish_decl (pushdecl (decl), init, NULL_TREE); } /* Given a chain of STRING_CST nodes, concatenate them into one STRING_CST and give it a suitable array-of-chars data type. */ tree combine_strings (strings) tree strings; { register tree value, t; register int length = 1; int wide_length = 0; int wide_flag = 0; int wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT; int nchars; if (TREE_CHAIN (strings)) { /* More than one in the chain, so concatenate. */ register char *p, *q; /* Don't include the \0 at the end of each substring, except for the last one. Count wide strings and ordinary strings separately. */ for (t = strings; t; t = TREE_CHAIN (t)) { if (TREE_TYPE (t) == wchar_array_type_node) { wide_length += (TREE_STRING_LENGTH (t) - wchar_bytes); wide_flag = 1; } else length += (TREE_STRING_LENGTH (t) - 1); } /* If anything is wide, the non-wides will be converted, which makes them take more space. */ if (wide_flag) length = length * wchar_bytes + wide_length; p = savealloc (length); /* Copy the individual strings into the new combined string. If the combined string is wide, convert the chars to ints for any individual strings that are not wide. */ q = p; for (t = strings; t; t = TREE_CHAIN (t)) { int len = (TREE_STRING_LENGTH (t) - ((TREE_TYPE (t) == wchar_array_type_node) ? wchar_bytes : 1)); if ((TREE_TYPE (t) == wchar_array_type_node) == wide_flag) { memcpy (q, TREE_STRING_POINTER (t), len); q += len; } else { int i; for (i = 0; i < len; i++) { if (WCHAR_TYPE_SIZE == HOST_BITS_PER_SHORT) ((short *) q)[i] = TREE_STRING_POINTER (t)[i]; else ((int *) q)[i] = TREE_STRING_POINTER (t)[i]; } q += len * wchar_bytes; } } if (wide_flag) { int i; for (i = 0; i < wchar_bytes; i++) *q++ = 0; } else *q = 0; value = make_node (STRING_CST); TREE_STRING_POINTER (value) = p; TREE_STRING_LENGTH (value) = length; } else { value = strings; length = TREE_STRING_LENGTH (value); if (TREE_TYPE (value) == wchar_array_type_node) wide_flag = 1; } /* Compute the number of elements, for the array type. */ nchars = wide_flag ? length / wchar_bytes : length; /* Create the array type for the string constant. -Wwrite-strings says make the string constant an array of const char so that copying it to a non-const pointer will get a warning. For C++, this is the standard behavior. */ if (flag_const_strings && (! flag_traditional && ! flag_writable_strings)) { tree elements = build_type_variant (wide_flag ? wchar_type_node : char_type_node, 1, 0); TREE_TYPE (value) = build_array_type (elements, build_index_type (build_int_2 (nchars - 1, 0))); } else TREE_TYPE (value) = build_array_type (wide_flag ? wchar_type_node : char_type_node, build_index_type (build_int_2 (nchars - 1, 0))); TREE_CONSTANT (value) = 1; TREE_READONLY (value) = ! flag_writable_strings; TREE_STATIC (value) = 1; return value; } /* To speed up processing of attributes, we maintain an array of IDENTIFIER_NODES and the corresponding attribute types. */ /* Array to hold attribute information. */ static struct {enum attrs id; tree name; int min, max, decl_req;} attrtab[50]; static int attrtab_idx = 0; /* Add an entry to the attribute table above. */ static void add_attribute (id, string, min_len, max_len, decl_req) enum attrs id; const char *string; int min_len, max_len; int decl_req; { char buf[100]; attrtab[attrtab_idx].id = id; attrtab[attrtab_idx].name = get_identifier (string); attrtab[attrtab_idx].min = min_len; attrtab[attrtab_idx].max = max_len; attrtab[attrtab_idx++].decl_req = decl_req; sprintf (buf, "__%s__", string); attrtab[attrtab_idx].id = id; attrtab[attrtab_idx].name = get_identifier (buf); attrtab[attrtab_idx].min = min_len; attrtab[attrtab_idx].max = max_len; attrtab[attrtab_idx++].decl_req = decl_req; } /* Initialize attribute table. */ static void init_attributes () { add_attribute (A_PACKED, "packed", 0, 0, 0); add_attribute (A_NOCOMMON, "nocommon", 0, 0, 1); add_attribute (A_COMMON, "common", 0, 0, 1); add_attribute (A_NORETURN, "noreturn", 0, 0, 1); add_attribute (A_NORETURN, "volatile", 0, 0, 1); add_attribute (A_UNUSED, "unused", 0, 0, 0); add_attribute (A_CONST, "const", 0, 0, 1); add_attribute (A_T_UNION, "transparent_union", 0, 0, 0); add_attribute (A_CONSTRUCTOR, "constructor", 0, 0, 1); add_attribute (A_DESTRUCTOR, "destructor", 0, 0, 1); add_attribute (A_MODE, "mode", 1, 1, 1); add_attribute (A_SECTION, "section", 1, 1, 1); add_attribute (A_ALIGNED, "aligned", 0, 1, 0); add_attribute (A_FORMAT, "format", 3, 3, 1); add_attribute (A_FORMAT_ARG, "format_arg", 1, 1, 1); add_attribute (A_NONNULL, "nonnull", 0, -1, 1); add_attribute (A_SENTINEL, "sentinel", 0, 0, 1); add_attribute (A_WEAK, "weak", 0, 0, 1); add_attribute (A_ALIAS, "alias", 1, 1, 1); add_attribute (A_NO_INSTRUMENT_FUNCTION, "no_instrument_function", 0, 0, 1); add_attribute (A_NO_CHECK_MEMORY_USAGE, "no_check_memory_usage", 0, 0, 1); } /* Default implementation of valid_lang_attribute, below. By default, there are no language-specific attributes. */ static int default_valid_lang_attribute (attr_name, attr_args, decl, type) tree attr_name ATTRIBUTE_UNUSED; tree attr_args ATTRIBUTE_UNUSED; tree decl ATTRIBUTE_UNUSED; tree type ATTRIBUTE_UNUSED; { return 0; } /* Return a 1 if ATTR_NAME and ATTR_ARGS denote a valid language-specific attribute for either declaration DECL or type TYPE and 0 otherwise. */ int (*valid_lang_attribute) PROTO ((tree, tree, tree, tree)) = default_valid_lang_attribute; typedef struct function_attribute_info { struct function_attribute_info *next; enum attrs type; /* data added there */ } function_attribute_info; typedef struct function_attributes_info { struct function_attributes_info *next; /* next structure on the list */ tree name; /* identifier such as "printf" */ tree assembler_name; /* optional mangled identifier (for C++) */ function_attribute_info *first; } function_attributes_info; static function_attribute_info *new_function_format PROTO((enum format_type, int, int)); static function_attribute_info *new_international_format PROTO((int)); static function_attribute_info *new_nonnull_info PROTO((int)); static function_attribute_info *new_sentinel_info PROTO((int)); static function_attributes_info *insert_function_attribute PROTO((function_attributes_info *, tree, tree, function_attribute_info *)); /* Process the attributes listed in ATTRIBUTES and PREFIX_ATTRIBUTES and install them in NODE, which is either a DECL (including a TYPE_DECL) or a TYPE. PREFIX_ATTRIBUTES can appear after the declaration specifiers and declaration modifiers but before the declaration proper. */ void decl_attributes (node, attributes, prefix_attributes) tree node, attributes, prefix_attributes; { tree decl = 0, type = 0; int is_type = 0; tree a; function_attributes_info *list = NULL; if (attrtab_idx == 0) init_attributes (); if (TREE_CODE_CLASS (TREE_CODE (node)) == 'd') { decl = node; type = TREE_TYPE (decl); is_type = TREE_CODE (node) == TYPE_DECL; } else if (TREE_CODE_CLASS (TREE_CODE (node)) == 't') type = node, is_type = 1; #ifdef PRAGMA_INSERT_ATTRIBUTES /* If the code in c-pragma.c wants to insert some attributes then allow it to do so. Do this before allowing machine back ends to insert attributes, so that they have the opportunity to override anything done here. */ PRAGMA_INSERT_ATTRIBUTES (node, & attributes, & prefix_attributes); #endif #ifdef INSERT_ATTRIBUTES INSERT_ATTRIBUTES (node, & attributes, & prefix_attributes); #endif attributes = chainon (prefix_attributes, attributes); for (a = attributes; a; a = TREE_CHAIN (a)) { tree name = TREE_PURPOSE (a); tree args = TREE_VALUE (a); int i; enum attrs id; int length; for (i = 0; i < attrtab_idx; i++) if (attrtab[i].name == name) break; if (i == attrtab_idx) { if (! valid_machine_attribute (name, args, decl, type) && ! (* valid_lang_attribute) (name, args, decl, type)) warning ("`%s' attribute directive ignored", IDENTIFIER_POINTER (name)); else if (decl != 0) type = TREE_TYPE (decl); continue; } else if (attrtab[i].decl_req && decl == 0) { warning ("`%s' attribute does not apply to types", IDENTIFIER_POINTER (name)); continue; } else { length = list_length (args); if (length < attrtab[i].min || (attrtab[i].max != -1 && length > attrtab[i].max)) { error ("wrong number of arguments specified for `%s' attribute", IDENTIFIER_POINTER (name)); continue; } } id = attrtab[i].id; switch (id) { case A_PACKED: if (is_type) TYPE_PACKED (type) = 1; else if (TREE_CODE (decl) == FIELD_DECL) DECL_PACKED (decl) = 1; /* We can't set DECL_PACKED for a VAR_DECL, because the bit is used for DECL_REGISTER. It wouldn't mean anything anyway. */ else warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name)); break; case A_NOCOMMON: if (TREE_CODE (decl) == VAR_DECL) DECL_COMMON (decl) = 0; else warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name)); break; case A_COMMON: if (TREE_CODE (decl) == VAR_DECL) DECL_COMMON (decl) = 1; else warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name)); break; case A_NORETURN: if (TREE_CODE (decl) == FUNCTION_DECL) TREE_THIS_VOLATILE (decl) = 1; else if (TREE_CODE (type) == POINTER_TYPE && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE) TREE_TYPE (decl) = type = build_pointer_type (build_type_variant (TREE_TYPE (type), TREE_READONLY (TREE_TYPE (type)), 1)); else warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name)); break; case A_UNUSED: if (is_type) TREE_USED (type) = 1; else if (TREE_CODE (decl) == PARM_DECL || TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == FUNCTION_DECL || TREE_CODE (decl) == LABEL_DECL) TREE_USED (decl) = 1; else warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name)); break; case A_CONST: if (TREE_CODE (decl) == FUNCTION_DECL) TREE_READONLY (decl) = 1; else if (TREE_CODE (type) == POINTER_TYPE && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE) TREE_TYPE (decl) = type = build_pointer_type (build_type_variant (TREE_TYPE (type), 1, TREE_THIS_VOLATILE (TREE_TYPE (type)))); else warning ( "`%s' attribute ignored", IDENTIFIER_POINTER (name)); break; case A_T_UNION: if (is_type && TREE_CODE (type) == UNION_TYPE && (decl == 0 || (TYPE_FIELDS (type) != 0 && TYPE_MODE (type) == DECL_MODE (TYPE_FIELDS (type))))) TYPE_TRANSPARENT_UNION (type) = 1; else if (decl != 0 && TREE_CODE (decl) == PARM_DECL && TREE_CODE (type) == UNION_TYPE && TYPE_MODE (type) == DECL_MODE (TYPE_FIELDS (type))) DECL_TRANSPARENT_UNION (decl) = 1; else warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name)); break; case A_CONSTRUCTOR: if (TREE_CODE (decl) == FUNCTION_DECL && TREE_CODE (type) == FUNCTION_TYPE && decl_function_context (decl) == 0) { DECL_STATIC_CONSTRUCTOR (decl) = 1; TREE_USED (decl) = 1; } else warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name)); break; case A_DESTRUCTOR: if (TREE_CODE (decl) == FUNCTION_DECL && TREE_CODE (type) == FUNCTION_TYPE && decl_function_context (decl) == 0) { DECL_STATIC_DESTRUCTOR (decl) = 1; TREE_USED (decl) = 1; } else warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name)); break; case A_MODE: if (TREE_CODE (TREE_VALUE (args)) != IDENTIFIER_NODE) warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name)); else { int j; const char *p = IDENTIFIER_POINTER (TREE_VALUE (args)); int len = strlen (p); enum machine_mode mode = VOIDmode; tree typefm; if (len > 4 && p[0] == '_' && p[1] == '_' && p[len - 1] == '_' && p[len - 2] == '_') { char *newp = (char *) alloca (len - 1); strcpy (newp, &p[2]); newp[len - 4] = '\0'; p = newp; } /* Give this decl a type with the specified mode. First check for the special modes. */ if (! strcmp (p, "byte")) mode = byte_mode; else if (!strcmp (p, "word")) mode = word_mode; else if (! strcmp (p, "pointer")) mode = ptr_mode; else for (j = 0; j < NUM_MACHINE_MODES; j++) if (!strcmp (p, GET_MODE_NAME (j))) mode = (enum machine_mode) j; if (mode == VOIDmode) error ("unknown machine mode `%s'", p); else if (0 == (typefm = type_for_mode (mode, TREE_UNSIGNED (type)))) error ("no data type for mode `%s'", p); else { TREE_TYPE (decl) = type = typefm; DECL_SIZE (decl) = 0; layout_decl (decl, 0); } } break; case A_SECTION: #ifdef ASM_OUTPUT_SECTION_NAME if ((TREE_CODE (decl) == FUNCTION_DECL || TREE_CODE (decl) == VAR_DECL) && TREE_CODE (TREE_VALUE (args)) == STRING_CST) { if (TREE_CODE (decl) == VAR_DECL && current_function_decl != NULL_TREE && ! TREE_STATIC (decl)) error_with_decl (decl, "section attribute cannot be specified for local variables"); /* The decl may have already been given a section attribute from a previous declaration. Ensure they match. */ else if (DECL_SECTION_NAME (decl) != NULL_TREE && strcmp (TREE_STRING_POINTER (DECL_SECTION_NAME (decl)), TREE_STRING_POINTER (TREE_VALUE (args))) != 0) error_with_decl (node, "section of `%s' conflicts with previous declaration"); else DECL_SECTION_NAME (decl) = TREE_VALUE (args); } else error_with_decl (node, "section attribute not allowed for `%s'"); #else error_with_decl (node, "section attributes are not supported for this target"); #endif break; case A_ALIGNED: { tree align_expr = (args ? TREE_VALUE (args) : size_int (BIGGEST_ALIGNMENT / BITS_PER_UNIT)); int align; /* Strip any NOPs of any kind. */ while (TREE_CODE (align_expr) == NOP_EXPR || TREE_CODE (align_expr) == CONVERT_EXPR || TREE_CODE (align_expr) == NON_LVALUE_EXPR) align_expr = TREE_OPERAND (align_expr, 0); if (TREE_CODE (align_expr) != INTEGER_CST) { error ("requested alignment is not a constant"); continue; } align = TREE_INT_CST_LOW (align_expr) * BITS_PER_UNIT; if (exact_log2 (align) == -1) error ("requested alignment is not a power of 2"); else if (is_type) TYPE_ALIGN (type) = align; else if (TREE_CODE (decl) != VAR_DECL && TREE_CODE (decl) != FIELD_DECL) error_with_decl (decl, "alignment may not be specified for `%s'"); else DECL_ALIGN (decl) = align; } break; case A_FORMAT: { tree format_type_id = TREE_VALUE (args); tree format_num_expr = TREE_VALUE (TREE_CHAIN (args)); tree first_arg_num_expr = TREE_VALUE (TREE_CHAIN (TREE_CHAIN (args))); int format_num; int first_arg_num; enum format_type format_type; tree argument; int arg_num; if (TREE_CODE (decl) != FUNCTION_DECL) { error_with_decl (decl, "argument format specified for non-function `%s'"); continue; } if (TREE_CODE (format_type_id) != IDENTIFIER_NODE) { error ("unrecognized format specifier"); continue; } else { const char *p = IDENTIFIER_POINTER (format_type_id); if (!strcmp (p, "printf") || !strcmp (p, "__printf__")) format_type = printf_format_type; else if (!strcmp (p, "scanf") || !strcmp (p, "__scanf__")) format_type = scanf_format_type; else if (!strcmp (p, "strftime") || !strcmp (p, "__strftime__")) format_type = strftime_format_type; else { warning ("`%s' is an unrecognized format function type", p); continue; } } /* Strip any conversions from the string index and first arg number and verify they are constants. */ while (TREE_CODE (format_num_expr) == NOP_EXPR || TREE_CODE (format_num_expr) == CONVERT_EXPR || TREE_CODE (format_num_expr) == NON_LVALUE_EXPR) format_num_expr = TREE_OPERAND (format_num_expr, 0); while (TREE_CODE (first_arg_num_expr) == NOP_EXPR || TREE_CODE (first_arg_num_expr) == CONVERT_EXPR || TREE_CODE (first_arg_num_expr) == NON_LVALUE_EXPR) first_arg_num_expr = TREE_OPERAND (first_arg_num_expr, 0); if (TREE_CODE (format_num_expr) != INTEGER_CST || TREE_CODE (first_arg_num_expr) != INTEGER_CST) { error ("format string has non-constant operand number"); continue; } format_num = TREE_INT_CST_LOW (format_num_expr); first_arg_num = TREE_INT_CST_LOW (first_arg_num_expr); if (first_arg_num != 0 && first_arg_num <= format_num) { error ("format string arg follows the args to be formatted"); continue; } /* If a parameter list is specified, verify that the format_num argument is actually a string, in case the format attribute is in error. */ argument = TYPE_ARG_TYPES (type); if (argument) { for (arg_num = 1; ; ++arg_num) { if (argument == 0 || arg_num == format_num) break; argument = TREE_CHAIN (argument); } if (! argument || TREE_CODE (TREE_VALUE (argument)) != POINTER_TYPE || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_VALUE (argument))) != char_type_node)) { error ("format string arg not a string type"); continue; } if (first_arg_num != 0) { /* Verify that first_arg_num points to the last arg, the ... */ while (argument) arg_num++, argument = TREE_CHAIN (argument); if (arg_num != first_arg_num) { error ("args to be formatted is not ..."); continue; } } } list = insert_function_attribute (list, DECL_NAME (decl), DECL_ASSEMBLER_NAME (decl), new_function_format (format_type, format_num, first_arg_num)); break; } case A_FORMAT_ARG: { tree format_num_expr = TREE_VALUE (args); int format_num, arg_num; tree argument; if (TREE_CODE (decl) != FUNCTION_DECL) { error_with_decl (decl, "argument format specified for non-function `%s'"); continue; } /* Strip any conversions from the first arg number and verify it is a constant. */ while (TREE_CODE (format_num_expr) == NOP_EXPR || TREE_CODE (format_num_expr) == CONVERT_EXPR || TREE_CODE (format_num_expr) == NON_LVALUE_EXPR) format_num_expr = TREE_OPERAND (format_num_expr, 0); if (TREE_CODE (format_num_expr) != INTEGER_CST) { error ("format string has non-constant operand number"); continue; } format_num = TREE_INT_CST_LOW (format_num_expr); /* If a parameter list is specified, verify that the format_num argument is actually a string, in case the format attribute is in error. */ argument = TYPE_ARG_TYPES (type); if (argument) { for (arg_num = 1; ; ++arg_num) { if (argument == 0 || arg_num == format_num) break; argument = TREE_CHAIN (argument); } if (! argument || TREE_CODE (TREE_VALUE (argument)) != POINTER_TYPE || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_VALUE (argument))) != char_type_node)) { error ("format string arg not a string type"); continue; } } if (TREE_CODE (TREE_TYPE (TREE_TYPE (decl))) != POINTER_TYPE || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (TREE_TYPE (decl)))) != char_type_node)) { error ("function does not return string type"); continue; } list = insert_function_attribute (list, DECL_NAME (decl), DECL_ASSEMBLER_NAME (decl), new_international_format (format_num)); break; } case A_NONNULL: if (TREE_CODE (decl) != FUNCTION_DECL) { error_with_decl (decl, "nonnull attribute specified for non-function `%s'"); continue; } /* No argument number: assume a full prototype, all pointers should be non null. */ if (!args) { tree argument; int arg_num; argument = TYPE_ARG_TYPES (type); if (!argument) { error_with_decl (decl, "nonnull attribute without arguments on a non-prototype `%s'"); continue; } for (arg_num = 1; ; ++arg_num) { if (argument == 0) break; if (TREE_CODE (TREE_VALUE (argument)) == POINTER_TYPE) list = insert_function_attribute (list, DECL_NAME (decl), DECL_ASSEMBLER_NAME (decl), new_nonnull_info (arg_num)); argument = TREE_CHAIN (argument); } break; } for (; args; args = TREE_CHAIN (args)) { tree argument; tree arg_num_expr = TREE_VALUE (args); int arg_num, ck_num; /* Strip any conversions from the arg number and verify they are constants. */ while (TREE_CODE (arg_num_expr) == NOP_EXPR || TREE_CODE (arg_num_expr) == CONVERT_EXPR || TREE_CODE (arg_num_expr) == NON_LVALUE_EXPR) arg_num_expr = TREE_OPERAND (arg_num_expr, 0); if (TREE_CODE (arg_num_expr) != INTEGER_CST) { error ("nonnull argument has non-constant operand number"); continue; } arg_num = TREE_INT_CST_LOW (arg_num_expr); /* If a parameter list is specified, verify that the arg_num argument is actually a pointer, in case the attribute is in error. */ argument = TYPE_ARG_TYPES (type); if (argument) { for (ck_num = 1; ; ++ck_num) { if (argument == 0 || ck_num == arg_num) break; argument = TREE_CHAIN (argument); } if (! argument || TREE_CODE (TREE_VALUE (argument)) != POINTER_TYPE) { error ("nonnull argument not a pointer type"); continue; } } list = insert_function_attribute (list, DECL_NAME (decl), DECL_ASSEMBLER_NAME (decl), new_nonnull_info (arg_num)); } break; case A_SENTINEL: if (TREE_CODE (decl) != FUNCTION_DECL) { error_with_decl (decl, "sentinel attribute specified for non-function `%s'"); continue; } if (args) { error_with_decl (decl, "sentinel attribute does not take arguments"); continue; } /* No argument number: assume a full prototype, find ellipsis location. */ if (!args) { tree argument; int arg_num; arg_num = 0; argument = TYPE_ARG_TYPES (type); if (!argument) { error_with_decl (decl, "sentinel attribute without arguments on a non-prototype `%s'"); continue; } while (argument) arg_num++, argument = TREE_CHAIN (argument); list = insert_function_attribute (list, DECL_NAME (decl), DECL_ASSEMBLER_NAME (decl), new_sentinel_info (arg_num)); } break; case A_WEAK: declare_weak (decl); break; case A_ALIAS: if ((TREE_CODE (decl) == FUNCTION_DECL && DECL_INITIAL (decl)) || (TREE_CODE (decl) != FUNCTION_DECL && ! DECL_EXTERNAL (decl))) error_with_decl (decl, "`%s' defined both normally and as an alias"); else if (decl_function_context (decl) == 0) { tree id; id = TREE_VALUE (args); if (TREE_CODE (id) != STRING_CST) { error ("alias arg not a string"); break; } id = get_identifier (TREE_STRING_POINTER (id)); if (TREE_CODE (decl) == FUNCTION_DECL) DECL_INITIAL (decl) = error_mark_node; else DECL_EXTERNAL (decl) = 0; assemble_alias (decl, id); } else warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name)); break; case A_NO_CHECK_MEMORY_USAGE: if (TREE_CODE (decl) != FUNCTION_DECL) { error_with_decl (decl, "`%s' attribute applies only to functions", IDENTIFIER_POINTER (name)); } else if (DECL_INITIAL (decl)) { error_with_decl (decl, "can't set `%s' attribute after definition", IDENTIFIER_POINTER (name)); } else DECL_NO_CHECK_MEMORY_USAGE (decl) = 1; break; case A_NO_INSTRUMENT_FUNCTION: if (TREE_CODE (decl) != FUNCTION_DECL) { error_with_decl (decl, "`%s' attribute applies only to functions", IDENTIFIER_POINTER (name)); } else if (DECL_INITIAL (decl)) { error_with_decl (decl, "can't set `%s' attribute after definition", IDENTIFIER_POINTER (name)); } else DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl) = 1; break; } } } /* Split SPECS_ATTRS, a list of declspecs and prefix attributes, into two lists. SPECS_ATTRS may also be just a typespec (eg: RECORD_TYPE). The head of the declspec list is stored in DECLSPECS. The head of the attribute list is stored in PREFIX_ATTRIBUTES. Note that attributes in SPECS_ATTRS are stored in the TREE_PURPOSE of the list elements. We drop the containing TREE_LIST nodes and link the resulting attributes together the way decl_attributes expects them. */ void split_specs_attrs (specs_attrs, declspecs, prefix_attributes) tree specs_attrs; tree *declspecs, *prefix_attributes; { tree t, s, a, next, specs, attrs; /* This can happen in c++ (eg: decl: typespec initdecls ';'). */ if (specs_attrs != NULL_TREE && TREE_CODE (specs_attrs) != TREE_LIST) { *declspecs = specs_attrs; *prefix_attributes = NULL_TREE; return; } /* Remember to keep the lists in the same order, element-wise. */ specs = s = NULL_TREE; attrs = a = NULL_TREE; for (t = specs_attrs; t; t = next) { next = TREE_CHAIN (t); /* Declspecs have a non-NULL TREE_VALUE. */ if (TREE_VALUE (t) != NULL_TREE) { if (specs == NULL_TREE) specs = s = t; else { TREE_CHAIN (s) = t; s = t; } } else { if (attrs == NULL_TREE) attrs = a = TREE_PURPOSE (t); else { TREE_CHAIN (a) = TREE_PURPOSE (t); a = TREE_PURPOSE (t); } /* More attrs can be linked here, move A to the end. */ while (TREE_CHAIN (a) != NULL_TREE) a = TREE_CHAIN (a); } } /* Terminate the lists. */ if (s != NULL_TREE) TREE_CHAIN (s) = NULL_TREE; if (a != NULL_TREE) TREE_CHAIN (a) = NULL_TREE; /* All done. */ *declspecs = specs; *prefix_attributes = attrs; } /* Strip attributes from SPECS_ATTRS, a list of declspecs and attributes. This function is used by the parser when a rule will accept attributes in a particular position, but we don't want to support that just yet. A warning is issued for every ignored attribute. */ tree strip_attrs (specs_attrs) tree specs_attrs; { tree specs, attrs; split_specs_attrs (specs_attrs, &specs, &attrs); while (attrs) { warning ("`%s' attribute ignored", IDENTIFIER_POINTER (TREE_PURPOSE (attrs))); attrs = TREE_CHAIN (attrs); } return specs; } /* Check a printf/fprintf/sprintf/scanf/fscanf/sscanf format against a parameter list. */ #define T_I &integer_type_node #define T_L &long_integer_type_node #define T_LL &long_long_integer_type_node #define T_S &short_integer_type_node #define T_UI &unsigned_type_node #define T_UL &long_unsigned_type_node #define T_ULL &long_long_unsigned_type_node #define T_US &short_unsigned_type_node #define T_F &float_type_node #define T_D &double_type_node #define T_LD &long_double_type_node #define T_C &char_type_node #define T_UC &unsigned_char_type_node #define T_V &void_type_node #define T_W &wchar_type_node #define T_ST &sizetype typedef struct { const char *format_chars; int pointer_count; /* Type of argument if no length modifier is used. */ tree *nolen; /* Type of argument if length modifier for shortening to byte is used. If NULL, then this modifier is not allowed. */ tree *hhlen; /* Type of argument if length modifier for shortening is used. If NULL, then this modifier is not allowed. */ tree *hlen; /* Type of argument if length modifier `l' is used. If NULL, then this modifier is not allowed. */ tree *llen; /* Type of argument if length modifier `q' or `ll' is used. If NULL, then this modifier is not allowed. */ tree *qlen; /* Type of argument if length modifier `L' is used. If NULL, then this modifier is not allowed. */ tree *bigllen; /* Type of argument if length modifier `Z' is used. If NULL, then this modifier is not allowed. */ tree *zlen; /* List of other modifier characters allowed with these options. */ const char *flag_chars; } format_char_info; static format_char_info print_char_table[] = { { "di", 0, T_I, T_I, T_I, T_L, T_LL, T_LL, T_ST, "-wp0 +" }, { "oxX", 0, T_UI, T_UI, T_UI, T_UL, T_ULL, T_ULL, T_ST, "-wp0#" }, { "u", 0, T_UI, T_UI, T_UI, T_UL, T_ULL, T_ULL, T_ST, "-wp0" }, /* A GNU extension. */ { "m", 0, T_V, NULL, NULL, NULL, NULL, NULL, NULL, "-wp" }, { "feEgGaA", 0, T_D, NULL, NULL, NULL, NULL, T_LD, NULL, "-wp0 +#" }, { "c", 0, T_I, NULL, NULL, T_W, NULL, NULL, NULL, "-w" }, { "C", 0, T_W, NULL, NULL, NULL, NULL, NULL, NULL, "-w" }, { "s", 1, T_C, NULL, NULL, T_W, NULL, NULL, NULL, "-wp" }, { "S", 1, T_W, NULL, NULL, NULL, NULL, NULL, NULL, "-wp" }, { "p", 1, T_V, NULL, NULL, NULL, NULL, NULL, NULL, "-w" }, { "n", 1, T_I, NULL, T_S, T_L, T_LL, NULL, NULL, "" }, { NULL, 0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL } }; static format_char_info scan_char_table[] = { { "di", 1, T_I, T_C, T_S, T_L, T_LL, T_LL, NULL, "*" }, { "ouxX", 1, T_UI, T_UC, T_US, T_UL, T_ULL, T_ULL, NULL, "*" }, { "efgEGaA", 1, T_F, NULL, NULL, T_D, NULL, T_LD, NULL, "*" }, { "c", 1, T_C, NULL, NULL, T_W, NULL, NULL, NULL, "*" }, { "s", 1, T_C, NULL, NULL, T_W, NULL, NULL, NULL, "*a" }, { "[", 1, T_C, NULL, NULL, NULL, NULL, NULL, NULL, "*a" }, { "C", 1, T_W, NULL, NULL, NULL, NULL, NULL, NULL, "*" }, { "S", 1, T_W, NULL, NULL, NULL, NULL, NULL, NULL, "*a" }, { "p", 2, T_V, NULL, NULL, NULL, NULL, NULL, NULL, "*" }, { "n", 1, T_I, T_C, T_S, T_L, T_LL, NULL, NULL, "" }, { NULL, 0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL } }; /* Handle format characters recognized by glibc's strftime.c. '2' - MUST do years as only two digits '3' - MAY do years as only two digits (depending on locale) 'E' - E modifier is acceptable 'O' - O modifier is acceptable to Standard C 'o' - O modifier is acceptable as a GNU extension 'G' - other GNU extensions */ static format_char_info time_char_table[] = { { "y", 0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, "2EO-_0w" }, { "D", 0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, "2" }, { "g", 0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, "2O-_0w" }, { "cx", 0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, "3E" }, { "%RTXnrt", 0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, "" }, { "P", 0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, "G" }, { "HIMSUWdemw", 0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, "-_0Ow" }, { "Vju", 0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, "-_0Oow" }, { "Gklsz", 0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, "-_0OGw" }, { "ABZa", 0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, "^#" }, { "p", 0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, "#" }, { "bh", 0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, "^" }, { "CY", 0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, "-_0EOw" }, { NULL, 0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL } }; static function_attributes_info *function_attributes_list = NULL; /* Specialized flavors of function_attribute_info. */ typedef struct function_format_info { struct function_attribute_info *next; enum attrs type; enum format_type format_type; /* type of format (printf, scanf, etc.) */ int format_num; /* number of format argument */ int first_arg_num; /* number of first arg (zero for varargs) */ } function_format_info; typedef struct international_format_info { struct function_attribute_info *next; enum attrs type; int format_num; /* number of format argument */ } international_format_info; typedef struct nonnull_info { struct function_attribute_info *next; enum attrs type; int argument_num; /* number of non-null argument */ } nonnull_info; typedef struct sentinel_info { struct function_attribute_info *next; enum attrs type; int argument_num; /* number of non-null argument */ } sentinel_info; static function_attribute_info *find_function_attribute PROTO((tree, tree, enum attrs)); static void check_format_info PROTO((function_format_info *, tree)); static void check_nonnull_info PROTO((nonnull_info *, tree)); static void check_sentinel_info PROTO((sentinel_info *, tree)); /* Helper function for setting up initial attribute for printf-like functions, since the format argument is also non-null checked for those. */ static void add_function_format (name, type, arg1, arg2) const char *name; enum format_type type; int arg1; int arg2; { tree t = get_identifier (name); insert_function_attribute (insert_function_attribute (NULL, t, NULL_TREE, new_function_format(type, arg1, arg2)), t, NULL_TREE, new_nonnull_info (arg1)); } /* Initialize the table of functions to perform format checking on. The ANSI functions are always checked (whether is included or not), since it is common to call printf without including . There shouldn't be a problem with this, since ANSI reserves these function names whether you include the header file or not. In any case, the checking is harmless. Also initialize the name of function that modify the format string for internationalization purposes. */ void init_function_format_info () { add_function_format ("printf", printf_format_type, 1, 2); add_function_format ("fprintf", printf_format_type, 2, 3); add_function_format ("sprintf", printf_format_type, 2, 3); add_function_format ("scanf", scanf_format_type, 1, 2); add_function_format ("fscanf", scanf_format_type, 2, 3); add_function_format ("sscanf", scanf_format_type, 2, 3); add_function_format ("vprintf", printf_format_type, 1, 0); add_function_format ("vfprintf", printf_format_type, 2, 0); add_function_format ("vsprintf", printf_format_type, 2, 0); add_function_format ("strftime", strftime_format_type, 3, 0); insert_function_attribute (NULL, get_identifier ("gettext"), NULL_TREE, new_international_format (1)); insert_function_attribute (NULL, get_identifier ("dgettext"), NULL_TREE, new_international_format (2)); insert_function_attribute (NULL, get_identifier ("dcgettext"), NULL_TREE, new_international_format (2)); } /* Create information record for argument format checking. FORMAT_TYPE specifies the type of format checking. FORMAT_NUM is the number of the argument which is the format control string (starting from 1). FIRST_ARG_NUM is the number of the first actual argument to check against the format string, or zero if no checking is not be done (e.g. for varargs such as vfprintf). */ static function_attribute_info * new_function_format (format_type, format_num, first_arg_num) enum format_type format_type; int format_num; int first_arg_num; { function_format_info *info; info = (function_format_info *) xmalloc (sizeof (function_format_info)); info->next = NULL; info->type = A_FORMAT; info->format_type = format_type; info->format_num = format_num; info->first_arg_num = first_arg_num; return (function_attribute_info *) (info); } /* Create information record for functions that modify the format argument to format functions. FUNCTION_IDENT is the identifier node for the name of the function (its decl need not exist yet) and FORMAT_NUM is the number of the argument which is the format control string (starting from 1). */ static function_attribute_info * new_international_format (format_num) int format_num; { international_format_info *info; info = (international_format_info *) xmalloc (sizeof (international_format_info)); info->next = NULL; info->type = A_FORMAT_ARG; info->format_num = format_num; return (function_attribute_info *) (info); } /* Create information record for functions with non-null parameters. ARGUMENT_NUM is the number of the argument to check. */ static function_attribute_info * new_nonnull_info (argument_num) int argument_num; { nonnull_info *info; info = (nonnull_info *) xmalloc (sizeof (nonnull_info)); info->next = NULL; info->type = A_NONNULL; info->argument_num = argument_num; return (function_attribute_info *) (info); } /* Create information record for functions with sentinel parameters ARGUMENT_NUM is the number of the argument to check. */ static function_attribute_info * new_sentinel_info (argument_num) int argument_num; { sentinel_info *info; info = (sentinel_info *) xmalloc (sizeof (nonnull_info)); info->next = NULL; info->type = A_SENTINEL; info->argument_num = argument_num; return (function_attribute_info *) (info); } /* Record attribute information for the names of function. Used as: * newlist = insert_function_attribute (old, name, asm, new_xxx (...) ); * In reality, newlist == old if old != NULL, but clients don't need to * depend on that. */ static function_attributes_info * insert_function_attribute (list, name, assembler_name, info) function_attributes_info *list; tree name; tree assembler_name; function_attribute_info *info; { if (! list) /* Re-use existing structure if it's there. */ { for (list = function_attributes_list; list; list = list->next) { if (list->name == name && list->assembler_name == assembler_name) { function_attribute_info *i, *j; /* Remove existing attributes. Maybe we should have a flag * to mark compiler built-in attributes ? Or always warn if * we override existing attributes ? */ for (i = list->first; i; i = j) { j = i->next; free (i); } list->first = NULL; break; } } } if (! list) { list = (function_attributes_info *) xmalloc (sizeof (function_format_info)); list->next = function_attributes_list; function_attributes_list = list; list->name = name; list->assembler_name = assembler_name; list->first = NULL; } info->next = list->first; list->first = info; return list; } static void tfaff () { warning ("too few arguments for format"); } /* Check the argument list of a call to printf, scanf, etc. NAME is the function identifier. ASSEMBLER_NAME is the function's assembler identifier. (Either NAME or ASSEMBLER_NAME, but not both, may be NULL_TREE.) PARAMS is the list of argument values. */ void check_function_format (name, assembler_name, params) tree name; tree assembler_name; tree params; { function_attributes_info *info; function_attribute_info *ck; /* See if this function has attributes. */ for (info = function_attributes_list; info; info = info->next) { if (info->assembler_name ? (info->assembler_name == assembler_name) : (info->name == name)) { /* Yup; check those attributes. */ for (ck = info->first; ck; ck = ck->next) { switch (ck->type) { case A_FORMAT: check_format_info ((function_format_info *)ck, params); break; case A_NONNULL: check_nonnull_info ((nonnull_info *)ck, params); break; case A_SENTINEL: check_sentinel_info ((sentinel_info *)ck, params); break; } } break; } } } /* Find a function attribute corresponding to given function names, and a given attribute TYPE. */ static function_attribute_info * find_function_attribute(name, assembler_name, type) tree name; tree assembler_name; enum attrs type; { function_attributes_info *info; function_attribute_info *ck; ck = NULL; for (info = function_attributes_list; info; info = info->next) if (info->assembler_name ? (info->assembler_name == assembler_name) : (info->name == name)) { for (ck = info->first; ck; ck = ck->next) { if (ck->type == type) break; } break; } return ck; } /* Reduce an argument pointer to handle some non-trivial common cases. */ static tree reduce_pointer (arg) tree arg; { /* We can only check the argument if it's a string constant. */ while (TREE_CODE (arg) == NOP_EXPR) arg = TREE_OPERAND (arg, 0); /* strip coercion */ if (TREE_CODE (arg) == CALL_EXPR && TREE_CODE (TREE_OPERAND (arg, 0)) == ADDR_EXPR && (TREE_CODE (TREE_OPERAND (TREE_OPERAND (arg, 0), 0)) == FUNCTION_DECL)) { tree function = TREE_OPERAND (TREE_OPERAND (arg, 0), 0); /* See if this is a call to a known internationalization function that modifies the format arg. */ international_format_info *info; info = (international_format_info *) find_function_attribute (DECL_NAME (function), DECL_ASSEMBLER_NAME (function), A_FORMAT_ARG); if (info) { tree inner_args; int i; for (inner_args = TREE_OPERAND (arg, 1), i = 1; inner_args != 0; inner_args = TREE_CHAIN (inner_args), i++) if (i == info->format_num) { arg = TREE_VALUE (inner_args); while (TREE_CODE (arg) == NOP_EXPR) arg = TREE_OPERAND (arg, 0); } } } return arg; } /* Check the argument list for non-null pointers. INFO points to the nonnull_info structure. PARAMS is the list of argument values. */ static void check_nonnull_info (info, params) nonnull_info *info; tree params; { tree arg; int arg_num; /* Skip to checked argument. If the argument isn't available, there's no work for us to do; prototype checking will catch the problem. */ for (arg_num = 1; ; ++arg_num) { if (params == 0) return; if (arg_num == info->argument_num) break; params = TREE_CHAIN (params); } arg = TREE_VALUE (params); if (arg == 0) return; arg = reduce_pointer (arg); if (integer_zerop (arg)) { warning ("null argument #%d", arg_num); return; } } /* Check the argument list for sentinel values. INFO points to the sentinel_info structure. PARAMS is the list of argument values. */ static void check_sentinel_info (info, params) sentinel_info *info; tree params; { tree arg; int arg_num; /* Skip to first checked argument. If the argument isn't available, there's no work for us to do; prototype checking will catch the problem. */ for (arg_num = 1; ; ++arg_num) { if (params == 0) return; if (arg_num == info->argument_num) break; params = TREE_CHAIN (params); } while (params != 0) { arg = TREE_VALUE (params); if (arg == 0) break; while (TREE_CODE (arg) == NOP_EXPR) arg = TREE_OPERAND (arg, 0); /* strip coercion */ if (POINTER_TYPE_P (TREE_TYPE (arg)) && integer_zerop (arg)) return; params = TREE_CHAIN (params); } warning("couldn't find sentinel value starting at %d", arg_num); } /* Check the argument list of a call to printf, scanf, etc. INFO points to the function_format_info structure. PARAMS is the list of argument values. */ static void check_format_info (info, params) function_format_info *info; tree params; { int i; int arg_num; int suppressed, wide, precise; int length_char = 0; int format_char; int format_length; tree format_tree; tree cur_param; tree cur_type; tree wanted_type; tree first_fillin_param; const char *format_chars; format_char_info *fci = NULL; char flag_chars[8]; int has_operand_number = 0; /* Skip to format argument. If the argument isn't available, there's no work for us to do; prototype checking will catch the problem. */ for (arg_num = 1; ; ++arg_num) { if (params == 0) return; if (arg_num == info->format_num) break; params = TREE_CHAIN (params); } format_tree = TREE_VALUE (params); params = TREE_CHAIN (params); if (format_tree == 0) return; format_tree = reduce_pointer (format_tree); if (TREE_CODE (format_tree) != ADDR_EXPR) return; format_tree = TREE_OPERAND (format_tree, 0); if (TREE_CODE (format_tree) != STRING_CST) return; format_chars = TREE_STRING_POINTER (format_tree); format_length = TREE_STRING_LENGTH (format_tree); if (format_length <= 1) warning ("zero-length format string"); if (format_chars[--format_length] != 0) { warning ("unterminated format string"); return; } /* Skip to first argument to check. */ while (arg_num + 1 < info->first_arg_num) { if (params == 0) return; params = TREE_CHAIN (params); ++arg_num; } first_fillin_param = params; while (1) { int aflag; if (*format_chars == 0) { if (format_chars - TREE_STRING_POINTER (format_tree) != format_length) warning ("embedded `\\0' in format"); if (info->first_arg_num != 0 && params != 0 && ! has_operand_number) warning ("too many arguments for format"); return; } if (*format_chars++ != '%') continue; if (*format_chars == 0) { warning ("spurious trailing `%%' in format"); continue; } if (*format_chars == '%') { ++format_chars; continue; } flag_chars[0] = 0; suppressed = wide = precise = FALSE; if (info->format_type == scanf_format_type) { suppressed = *format_chars == '*'; if (suppressed) ++format_chars; while (ISDIGIT (*format_chars)) ++format_chars; } else if (info->format_type == strftime_format_type) { while (*format_chars != 0 && index ("_-0^#", *format_chars) != 0) { if (pedantic) warning ("ANSI C does not support the strftime `%c' flag", *format_chars); if (index (flag_chars, *format_chars) != 0) { warning ("repeated `%c' flag in format", *format_chars); ++format_chars; } else { i = strlen (flag_chars); flag_chars[i++] = *format_chars++; flag_chars[i] = 0; } } while (ISDIGIT ((unsigned char) *format_chars)) { wide = TRUE; ++format_chars; } if (wide && pedantic) warning ("ANSI C does not support strftime format width"); if (*format_chars == 'E' || *format_chars == 'O') { i = strlen (flag_chars); flag_chars[i++] = *format_chars++; flag_chars[i] = 0; if (*format_chars == 'E' || *format_chars == 'O') { warning ("multiple E/O modifiers in format"); while (*format_chars == 'E' || *format_chars == 'O') ++format_chars; } } } else if (info->format_type == printf_format_type) { /* See if we have a number followed by a dollar sign. If we do, it is an operand number, so set PARAMS to that operand. */ if (*format_chars >= '0' && *format_chars <= '9') { const char *p = format_chars; while (*p >= '0' && *p++ <= '9') ; if (*p == '$') { int opnum = atoi (format_chars); params = first_fillin_param; format_chars = p + 1; has_operand_number = 1; for (i = 1; i < opnum && params != 0; i++) params = TREE_CHAIN (params); if (opnum == 0 || params == 0) { warning ("operand number out of range in format"); return; } } } while (*format_chars != 0 && index (" +#0-", *format_chars) != 0) { if (index (flag_chars, *format_chars) != 0) warning ("repeated `%c' flag in format", *format_chars++); else { i = strlen (flag_chars); flag_chars[i++] = *format_chars++; flag_chars[i] = 0; } } /* "If the space and + flags both appear, the space flag will be ignored." */ if (index (flag_chars, ' ') != 0 && index (flag_chars, '+') != 0) warning ("use of both ` ' and `+' flags in format"); /* "If the 0 and - flags both appear, the 0 flag will be ignored." */ if (index (flag_chars, '0') != 0 && index (flag_chars, '-') != 0) warning ("use of both `0' and `-' flags in format"); if (*format_chars == '*') { wide = TRUE; /* "...a field width...may be indicated by an asterisk. In this case, an int argument supplies the field width..." */ ++format_chars; if (params == 0) { tfaff (); return; } if (info->first_arg_num != 0) { cur_param = TREE_VALUE (params); params = TREE_CHAIN (params); ++arg_num; /* size_t is generally not valid here. It will work on most machines, because size_t and int have the same mode. But might as well warn anyway, since it will fail on other machines. */ if ((TYPE_MAIN_VARIANT (TREE_TYPE (cur_param)) != integer_type_node) && (TYPE_MAIN_VARIANT (TREE_TYPE (cur_param)) != unsigned_type_node)) warning ("field width is not type int (arg %d)", arg_num); } } else { while (ISDIGIT (*format_chars)) { wide = TRUE; ++format_chars; } } if (*format_chars == '.') { precise = TRUE; ++format_chars; if (*format_chars != '*' && !ISDIGIT (*format_chars)) warning ("`.' not followed by `*' or digit in format"); /* "...a...precision...may be indicated by an asterisk. In this case, an int argument supplies the...precision." */ if (*format_chars == '*') { if (info->first_arg_num != 0) { ++format_chars; if (params == 0) { tfaff (); return; } cur_param = TREE_VALUE (params); params = TREE_CHAIN (params); ++arg_num; if (TYPE_MAIN_VARIANT (TREE_TYPE (cur_param)) != integer_type_node) warning ("field width is not type int (arg %d)", arg_num); } } else { while (ISDIGIT (*format_chars)) ++format_chars; } } } aflag = 0; if (info->format_type != strftime_format_type) { if (*format_chars == 'h' || *format_chars == 'l') length_char = *format_chars++; else if (*format_chars == 'q' || *format_chars == 'L') { length_char = *format_chars++; if (pedantic) warning ("ANSI C does not support the `%c' length modifier", length_char); } else if (*format_chars == 'Z') { length_char = *format_chars++; if (pedantic) warning ("ANSI C does not support the `Z' length modifier"); } else length_char = 0; if (length_char == 'l' && *format_chars == 'l') { length_char = 'q', format_chars++; /* FIXME: Is allowed in ISO C 9x. */ if (pedantic) warning ("ANSI C does not support the `ll' length modifier"); } else if (length_char == 'h' && *format_chars == 'h') { length_char = 'H', format_chars++; /* FIXME: Is allowed in ISO C 9x. */ if (pedantic) warning ("ANSI C does not support the `hh' length modifier"); } if (*format_chars == 'a' && info->format_type == scanf_format_type) { if (format_chars[1] == 's' || format_chars[1] == 'S' || format_chars[1] == '[') { /* `a' is used as a flag. */ aflag = 1; format_chars++; } } if (suppressed && length_char != 0) warning ("use of `*' and `%c' together in format", length_char); } format_char = *format_chars; if (format_char == 0 || (info->format_type != strftime_format_type && format_char == '%')) { warning ("conversion lacks type at end of format"); continue; } /* The m, C, and S formats are GNU extensions. */ if (pedantic && info->format_type != strftime_format_type && (format_char == 'm' || format_char == 'C' || format_char == 'S')) warning ("ANSI C does not support the `%c' format", format_char); /* ??? The a and A formats are C9X extensions, and should be allowed when a C9X option is added. */ if (pedantic && info->format_type != strftime_format_type && (format_char == 'a' || format_char == 'A')) warning ("ANSI C does not support the `%c' format", format_char); format_chars++; switch (info->format_type) { case printf_format_type: fci = print_char_table; break; case scanf_format_type: fci = scan_char_table; break; case strftime_format_type: fci = time_char_table; break; default: abort (); } while (fci->format_chars != 0 && index (fci->format_chars, format_char) == 0) ++fci; if (fci->format_chars == 0) { if (format_char >= 040 && format_char < 0177) warning ("unknown conversion type character `%c' in format", format_char); else warning ("unknown conversion type character 0x%x in format", format_char); continue; } if (pedantic) { if (index (fci->flag_chars, 'G') != 0) warning ("ANSI C does not support `%%%c'", format_char); if (index (fci->flag_chars, 'o') != 0 && index (flag_chars, 'O') != 0) warning ("ANSI C does not support `%%O%c'", format_char); } if (wide && index (fci->flag_chars, 'w') == 0) warning ("width used with `%c' format", format_char); if (index (fci->flag_chars, '2') != 0) warning ("`%%%c' yields only last 2 digits of year", format_char); else if (index (fci->flag_chars, '3') != 0) warning ("`%%%c' yields only last 2 digits of year in some locales", format_char); if (precise && index (fci->flag_chars, 'p') == 0) warning ("precision used with `%c' format", format_char); if (aflag && index (fci->flag_chars, 'a') == 0) { warning ("`a' flag used with `%c' format", format_char); /* To simplify the following code. */ aflag = 0; } /* The a flag is a GNU extension. */ else if (pedantic && aflag) warning ("ANSI C does not support the `a' flag"); if (info->format_type == scanf_format_type && format_char == '[') { /* Skip over scan set, in case it happens to have '%' in it. */ if (*format_chars == '^') ++format_chars; /* Find closing bracket; if one is hit immediately, then it's part of the scan set rather than a terminator. */ if (*format_chars == ']') ++format_chars; while (*format_chars && *format_chars != ']') ++format_chars; if (*format_chars != ']') /* The end of the format string was reached. */ warning ("no closing `]' for `%%[' format"); } if (suppressed) { if (index (fci->flag_chars, '*') == 0) warning ("suppression of `%c' conversion in format", format_char); continue; } for (i = 0; flag_chars[i] != 0; ++i) { if (index (fci->flag_chars, flag_chars[i]) == 0) warning ("flag `%c' used with type `%c'", flag_chars[i], format_char); } if (info->format_type == strftime_format_type) continue; if (precise && index (flag_chars, '0') != 0 && (format_char == 'd' || format_char == 'i' || format_char == 'o' || format_char == 'u' || format_char == 'x' || format_char == 'X')) warning ("`0' flag ignored with precision specifier and `%c' format", format_char); switch (length_char) { default: wanted_type = fci->nolen ? *(fci->nolen) : 0; break; case 'H': wanted_type = fci->hhlen ? *(fci->hhlen) : 0; break; case 'h': wanted_type = fci->hlen ? *(fci->hlen) : 0; break; case 'l': wanted_type = fci->llen ? *(fci->llen) : 0; break; case 'q': wanted_type = fci->qlen ? *(fci->qlen) : 0; break; case 'L': wanted_type = fci->bigllen ? *(fci->bigllen) : 0; break; case 'Z': wanted_type = fci->zlen ? *fci->zlen : 0; break; } if (wanted_type == 0) warning ("use of `%c' length character with `%c' type character", length_char, format_char); /* Finally. . .check type of argument against desired type! */ if (info->first_arg_num == 0) continue; if (fci->pointer_count == 0 && wanted_type == void_type_node) /* This specifier takes no argument. */ continue; if (params == 0) { tfaff (); return; } cur_param = TREE_VALUE (params); params = TREE_CHAIN (params); ++arg_num; cur_type = TREE_TYPE (cur_param); STRIP_NOPS (cur_param); /* Check the types of any additional pointer arguments that precede the "real" argument. */ for (i = 0; i < fci->pointer_count + aflag; ++i) { if (TREE_CODE (cur_type) == POINTER_TYPE) { cur_type = TREE_TYPE (cur_type); if (cur_param != 0 && TREE_CODE (cur_param) == ADDR_EXPR) cur_param = TREE_OPERAND (cur_param, 0); else cur_param = 0; continue; } if (TREE_CODE (cur_type) != ERROR_MARK) warning ((fci->pointer_count + aflag == 1 ? "format argument is not a pointer (arg %d)" : "format argument is not a pointer to a pointer (arg %d)"), arg_num); break; } /* See if this is an attempt to write into a const type with scanf or with printf "%n". */ if ((info->format_type == scanf_format_type || (info->format_type == printf_format_type && format_char == 'n')) && i == fci->pointer_count + aflag && wanted_type != 0 && TREE_CODE (cur_type) != ERROR_MARK && (TYPE_READONLY (cur_type) || (cur_param != 0 && (TREE_CODE_CLASS (TREE_CODE (cur_param)) == 'c' || (TREE_CODE_CLASS (TREE_CODE (cur_param)) == 'd' && TREE_READONLY (cur_param)))))) warning ("writing into constant object (arg %d)", arg_num); /* Check the type of the "real" argument, if there's a type we want. */ if (i == fci->pointer_count + aflag && wanted_type != 0 && TREE_CODE (cur_type) != ERROR_MARK && wanted_type != TYPE_MAIN_VARIANT (cur_type) /* If we want `void *', allow any pointer type. (Anything else would already have got a warning.) */ && ! (wanted_type == void_type_node && fci->pointer_count > 0) /* Don't warn about differences merely in signedness. */ && !(TREE_CODE (wanted_type) == INTEGER_TYPE && TREE_CODE (TYPE_MAIN_VARIANT (cur_type)) == INTEGER_TYPE && (TREE_UNSIGNED (wanted_type) ? wanted_type == (cur_type = unsigned_type (cur_type)) : wanted_type == (cur_type = signed_type (cur_type)))) /* Likewise, "signed char", "unsigned char" and "char" are equivalent but the above test won't consider them equivalent. */ && ! (wanted_type == char_type_node && (TYPE_MAIN_VARIANT (cur_type) == signed_char_type_node || TYPE_MAIN_VARIANT (cur_type) == unsigned_char_type_node))) { register const char *this; register const char *that; this = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (wanted_type))); that = 0; if (TREE_CODE (cur_type) != ERROR_MARK && TYPE_NAME (cur_type) != 0 && TREE_CODE (cur_type) != INTEGER_TYPE && !(TREE_CODE (cur_type) == POINTER_TYPE && TREE_CODE (TREE_TYPE (cur_type)) == INTEGER_TYPE)) { if (TREE_CODE (TYPE_NAME (cur_type)) == TYPE_DECL && DECL_NAME (TYPE_NAME (cur_type)) != 0) that = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (cur_type))); else that = IDENTIFIER_POINTER (TYPE_NAME (cur_type)); } /* A nameless type can't possibly match what the format wants. So there will be a warning for it. Make up a string to describe vaguely what it is. */ if (that == 0) { if (TREE_CODE (cur_type) == POINTER_TYPE) that = "pointer"; else that = "different type"; } /* Make the warning better in case of mismatch of int vs long. */ if (TREE_CODE (cur_type) == INTEGER_TYPE && TREE_CODE (wanted_type) == INTEGER_TYPE && TYPE_PRECISION (cur_type) == TYPE_PRECISION (wanted_type) && TYPE_NAME (cur_type) != 0 && TREE_CODE (TYPE_NAME (cur_type)) == TYPE_DECL) that = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (cur_type))); if (strcmp (this, that) != 0) warning ("%s format, %s arg (arg %d)", this, that, arg_num); } } } /* Print a warning if a constant expression had overflow in folding. Invoke this function on every expression that the language requires to be a constant expression. Note the ANSI C standard says it is erroneous for a constant expression to overflow. */ void constant_expression_warning (value) tree value; { if ((TREE_CODE (value) == INTEGER_CST || TREE_CODE (value) == REAL_CST || TREE_CODE (value) == COMPLEX_CST) && TREE_CONSTANT_OVERFLOW (value) && pedantic) pedwarn ("overflow in constant expression"); } /* Print a warning if an expression had overflow in folding. Invoke this function on every expression that (1) appears in the source code, and (2) might be a constant expression that overflowed, and (3) is not already checked by convert_and_check; however, do not invoke this function on operands of explicit casts. */ void overflow_warning (value) tree value; { if ((TREE_CODE (value) == INTEGER_CST || (TREE_CODE (value) == COMPLEX_CST && TREE_CODE (TREE_REALPART (value)) == INTEGER_CST)) && TREE_OVERFLOW (value)) { TREE_OVERFLOW (value) = 0; if (skip_evaluation == 0) warning ("integer overflow in expression"); } else if ((TREE_CODE (value) == REAL_CST || (TREE_CODE (value) == COMPLEX_CST && TREE_CODE (TREE_REALPART (value)) == REAL_CST)) && TREE_OVERFLOW (value)) { TREE_OVERFLOW (value) = 0; if (skip_evaluation == 0) warning ("floating point overflow in expression"); } } /* Print a warning if a large constant is truncated to unsigned, or if -Wconversion is used and a constant < 0 is converted to unsigned. Invoke this function on every expression that might be implicitly converted to an unsigned type. */ void unsigned_conversion_warning (result, operand) tree result, operand; { if (TREE_CODE (operand) == INTEGER_CST && TREE_CODE (TREE_TYPE (result)) == INTEGER_TYPE && TREE_UNSIGNED (TREE_TYPE (result)) && skip_evaluation == 0 && !int_fits_type_p (operand, TREE_TYPE (result))) { if (!int_fits_type_p (operand, signed_type (TREE_TYPE (result)))) /* This detects cases like converting -129 or 256 to unsigned char. */ warning ("large integer implicitly truncated to unsigned type"); else if (warn_conversion) warning ("negative integer implicitly converted to unsigned type"); } } /* Convert EXPR to TYPE, warning about conversion problems with constants. Invoke this function on every expression that is converted implicitly, i.e. because of language rules and not because of an explicit cast. */ tree convert_and_check (type, expr) tree type, expr; { tree t = convert (type, expr); if (TREE_CODE (t) == INTEGER_CST) { if (TREE_OVERFLOW (t)) { TREE_OVERFLOW (t) = 0; /* Do not diagnose overflow in a constant expression merely because a conversion overflowed. */ TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (expr); /* No warning for converting 0x80000000 to int. */ if (!(TREE_UNSIGNED (type) < TREE_UNSIGNED (TREE_TYPE (expr)) && TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE && TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (expr)))) /* If EXPR fits in the unsigned version of TYPE, don't warn unless pedantic. */ if ((pedantic || TREE_UNSIGNED (type) || ! int_fits_type_p (expr, unsigned_type (type))) && skip_evaluation == 0) warning ("overflow in implicit constant conversion"); } else unsigned_conversion_warning (t, expr); } return t; } void c_expand_expr_stmt (expr) tree expr; { /* Do default conversion if safe and possibly important, in case within ({...}). */ if ((TREE_CODE (TREE_TYPE (expr)) == ARRAY_TYPE && lvalue_p (expr)) || TREE_CODE (TREE_TYPE (expr)) == FUNCTION_TYPE) expr = default_conversion (expr); if (TREE_TYPE (expr) != error_mark_node && TYPE_SIZE (TREE_TYPE (expr)) == 0 && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE) error ("expression statement has incomplete type"); expand_expr_stmt (expr); } /* Validate the expression after `case' and apply default promotions. */ tree check_case_value (value) tree value; { if (value == NULL_TREE) return value; /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue. */ STRIP_TYPE_NOPS (value); if (TREE_CODE (value) != INTEGER_CST && value != error_mark_node) { error ("case label does not reduce to an integer constant"); value = error_mark_node; } else /* Promote char or short to int. */ value = default_conversion (value); constant_expression_warning (value); return value; } /* Return an integer type with BITS bits of precision, that is unsigned if UNSIGNEDP is nonzero, otherwise signed. */ tree type_for_size (bits, unsignedp) unsigned bits; int unsignedp; { if (bits == TYPE_PRECISION (integer_type_node)) return unsignedp ? unsigned_type_node : integer_type_node; if (bits == TYPE_PRECISION (signed_char_type_node)) return unsignedp ? unsigned_char_type_node : signed_char_type_node; if (bits == TYPE_PRECISION (short_integer_type_node)) return unsignedp ? short_unsigned_type_node : short_integer_type_node; if (bits == TYPE_PRECISION (long_integer_type_node)) return unsignedp ? long_unsigned_type_node : long_integer_type_node; if (bits == TYPE_PRECISION (long_long_integer_type_node)) return (unsignedp ? long_long_unsigned_type_node : long_long_integer_type_node); if (bits <= TYPE_PRECISION (intQI_type_node)) return unsignedp ? unsigned_intQI_type_node : intQI_type_node; if (bits <= TYPE_PRECISION (intHI_type_node)) return unsignedp ? unsigned_intHI_type_node : intHI_type_node; if (bits <= TYPE_PRECISION (intSI_type_node)) return unsignedp ? unsigned_intSI_type_node : intSI_type_node; if (bits <= TYPE_PRECISION (intDI_type_node)) return unsignedp ? unsigned_intDI_type_node : intDI_type_node; return 0; } /* Return a data type that has machine mode MODE. If the mode is an integer, then UNSIGNEDP selects between signed and unsigned types. */ tree type_for_mode (mode, unsignedp) enum machine_mode mode; int unsignedp; { if (mode == TYPE_MODE (integer_type_node)) return unsignedp ? unsigned_type_node : integer_type_node; if (mode == TYPE_MODE (signed_char_type_node)) return unsignedp ? unsigned_char_type_node : signed_char_type_node; if (mode == TYPE_MODE (short_integer_type_node)) return unsignedp ? short_unsigned_type_node : short_integer_type_node; if (mode == TYPE_MODE (long_integer_type_node)) return unsignedp ? long_unsigned_type_node : long_integer_type_node; if (mode == TYPE_MODE (long_long_integer_type_node)) return unsignedp ? long_long_unsigned_type_node : long_long_integer_type_node; if (mode == TYPE_MODE (intQI_type_node)) return unsignedp ? unsigned_intQI_type_node : intQI_type_node; if (mode == TYPE_MODE (intHI_type_node)) return unsignedp ? unsigned_intHI_type_node : intHI_type_node; if (mode == TYPE_MODE (intSI_type_node)) return unsignedp ? unsigned_intSI_type_node : intSI_type_node; if (mode == TYPE_MODE (intDI_type_node)) return unsignedp ? unsigned_intDI_type_node : intDI_type_node; #if HOST_BITS_PER_WIDE_INT >= 64 if (mode == TYPE_MODE (intTI_type_node)) return unsignedp ? unsigned_intTI_type_node : intTI_type_node; #endif if (mode == TYPE_MODE (float_type_node)) return float_type_node; if (mode == TYPE_MODE (double_type_node)) return double_type_node; if (mode == TYPE_MODE (long_double_type_node)) return long_double_type_node; if (mode == TYPE_MODE (build_pointer_type (char_type_node))) return build_pointer_type (char_type_node); if (mode == TYPE_MODE (build_pointer_type (integer_type_node))) return build_pointer_type (integer_type_node); return 0; } /* Return the minimum number of bits needed to represent VALUE in a signed or unsigned type, UNSIGNEDP says which. */ int min_precision (value, unsignedp) tree value; int unsignedp; { int log; /* If the value is negative, compute its negative minus 1. The latter adjustment is because the absolute value of the largest negative value is one larger than the largest positive value. This is equivalent to a bit-wise negation, so use that operation instead. */ if (tree_int_cst_sgn (value) < 0) value = fold (build1 (BIT_NOT_EXPR, TREE_TYPE (value), value)); /* Return the number of bits needed, taking into account the fact that we need one more bit for a signed than unsigned type. */ if (integer_zerop (value)) log = 0; else if (TREE_INT_CST_HIGH (value) != 0) log = HOST_BITS_PER_WIDE_INT + floor_log2 (TREE_INT_CST_HIGH (value)); else log = floor_log2 (TREE_INT_CST_LOW (value)); return log + 1 + ! unsignedp; } /* Print an error message for invalid operands to arith operation CODE. NOP_EXPR is used as a special case (see truthvalue_conversion). */ void binary_op_error (code) enum tree_code code; { register const char *opname; switch (code) { case NOP_EXPR: error ("invalid truth-value expression"); return; case PLUS_EXPR: opname = "+"; break; case MINUS_EXPR: opname = "-"; break; case MULT_EXPR: opname = "*"; break; case MAX_EXPR: opname = "max"; break; case MIN_EXPR: opname = "min"; break; case EQ_EXPR: opname = "=="; break; case NE_EXPR: opname = "!="; break; case LE_EXPR: opname = "<="; break; case GE_EXPR: opname = ">="; break; case LT_EXPR: opname = "<"; break; case GT_EXPR: opname = ">"; break; case LSHIFT_EXPR: opname = "<<"; break; case RSHIFT_EXPR: opname = ">>"; break; case TRUNC_MOD_EXPR: case FLOOR_MOD_EXPR: opname = "%"; break; case TRUNC_DIV_EXPR: case FLOOR_DIV_EXPR: opname = "/"; break; case BIT_AND_EXPR: opname = "&"; break; case BIT_IOR_EXPR: opname = "|"; break; case TRUTH_ANDIF_EXPR: opname = "&&"; break; case TRUTH_ORIF_EXPR: opname = "||"; break; case BIT_XOR_EXPR: opname = "^"; break; case LROTATE_EXPR: case RROTATE_EXPR: opname = "rotate"; break; default: opname = "unknown"; break; } error ("invalid operands to binary %s", opname); } /* Subroutine of build_binary_op, used for comparison operations. See if the operands have both been converted from subword integer types and, if so, perhaps change them both back to their original type. This function is also responsible for converting the two operands to the proper common type for comparison. The arguments of this function are all pointers to local variables of build_binary_op: OP0_PTR is &OP0, OP1_PTR is &OP1, RESTYPE_PTR is &RESULT_TYPE and RESCODE_PTR is &RESULTCODE. If this function returns nonzero, it means that the comparison has a constant value. What this function returns is an expression for that value. */ tree shorten_compare (op0_ptr, op1_ptr, restype_ptr, rescode_ptr) tree *op0_ptr, *op1_ptr; tree *restype_ptr; enum tree_code *rescode_ptr; { register tree type; tree op0 = *op0_ptr; tree op1 = *op1_ptr; int unsignedp0, unsignedp1; int real1, real2; tree primop0, primop1; enum tree_code code = *rescode_ptr; /* Throw away any conversions to wider types already present in the operands. */ primop0 = get_narrower (op0, &unsignedp0); primop1 = get_narrower (op1, &unsignedp1); /* Handle the case that OP0 does not *contain* a conversion but it *requires* conversion to FINAL_TYPE. */ if (op0 == primop0 && TREE_TYPE (op0) != *restype_ptr) unsignedp0 = TREE_UNSIGNED (TREE_TYPE (op0)); if (op1 == primop1 && TREE_TYPE (op1) != *restype_ptr) unsignedp1 = TREE_UNSIGNED (TREE_TYPE (op1)); /* If one of the operands must be floated, we cannot optimize. */ real1 = TREE_CODE (TREE_TYPE (primop0)) == REAL_TYPE; real2 = TREE_CODE (TREE_TYPE (primop1)) == REAL_TYPE; /* If first arg is constant, swap the args (changing operation so value is preserved), for canonicalization. Don't do this if the second arg is 0. */ if (TREE_CONSTANT (primop0) && ! integer_zerop (primop1) && ! real_zerop (primop1)) { register tree tem = primop0; register int temi = unsignedp0; primop0 = primop1; primop1 = tem; tem = op0; op0 = op1; op1 = tem; *op0_ptr = op0; *op1_ptr = op1; unsignedp0 = unsignedp1; unsignedp1 = temi; temi = real1; real1 = real2; real2 = temi; switch (code) { case LT_EXPR: code = GT_EXPR; break; case GT_EXPR: code = LT_EXPR; break; case LE_EXPR: code = GE_EXPR; break; case GE_EXPR: code = LE_EXPR; break; default: break; } *rescode_ptr = code; } /* If comparing an integer against a constant more bits wide, maybe we can deduce a value of 1 or 0 independent of the data. Or else truncate the constant now rather than extend the variable at run time. This is only interesting if the constant is the wider arg. Also, it is not safe if the constant is unsigned and the variable arg is signed, since in this case the variable would be sign-extended and then regarded as unsigned. Our technique fails in this case because the lowest/highest possible unsigned results don't follow naturally from the lowest/highest possible values of the variable operand. For just EQ_EXPR and NE_EXPR there is another technique that could be used: see if the constant can be faithfully represented in the other operand's type, by truncating it and reextending it and see if that preserves the constant's value. */ if (!real1 && !real2 && TREE_CODE (primop1) == INTEGER_CST && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr)) { int min_gt, max_gt, min_lt, max_lt; tree maxval, minval; /* 1 if comparison is nominally unsigned. */ int unsignedp = TREE_UNSIGNED (*restype_ptr); tree val; type = signed_or_unsigned_type (unsignedp0, TREE_TYPE (primop0)); /* If TYPE is an enumeration, then we need to get its min/max values from it's underlying integral type, not the enumerated type itself. */ if (TREE_CODE (type) == ENUMERAL_TYPE) type = type_for_size (TYPE_PRECISION (type), unsignedp0); maxval = TYPE_MAX_VALUE (type); minval = TYPE_MIN_VALUE (type); if (unsignedp && !unsignedp0) *restype_ptr = signed_type (*restype_ptr); if (TREE_TYPE (primop1) != *restype_ptr) primop1 = convert (*restype_ptr, primop1); if (type != *restype_ptr) { minval = convert (*restype_ptr, minval); maxval = convert (*restype_ptr, maxval); } if (unsignedp && unsignedp0) { min_gt = INT_CST_LT_UNSIGNED (primop1, minval); max_gt = INT_CST_LT_UNSIGNED (primop1, maxval); min_lt = INT_CST_LT_UNSIGNED (minval, primop1); max_lt = INT_CST_LT_UNSIGNED (maxval, primop1); } else { min_gt = INT_CST_LT (primop1, minval); max_gt = INT_CST_LT (primop1, maxval); min_lt = INT_CST_LT (minval, primop1); max_lt = INT_CST_LT (maxval, primop1); } val = 0; /* This used to be a switch, but Genix compiler can't handle that. */ if (code == NE_EXPR) { if (max_lt || min_gt) val = boolean_true_node; } else if (code == EQ_EXPR) { if (max_lt || min_gt) val = boolean_false_node; } else if (code == LT_EXPR) { if (max_lt) val = boolean_true_node; if (!min_lt) val = boolean_false_node; } else if (code == GT_EXPR) { if (min_gt) val = boolean_true_node; if (!max_gt) val = boolean_false_node; } else if (code == LE_EXPR) { if (!max_gt) val = boolean_true_node; if (min_gt) val = boolean_false_node; } else if (code == GE_EXPR) { if (!min_lt) val = boolean_true_node; if (max_lt) val = boolean_false_node; } /* If primop0 was sign-extended and unsigned comparison specd, we did a signed comparison above using the signed type bounds. But the comparison we output must be unsigned. Also, for inequalities, VAL is no good; but if the signed comparison had *any* fixed result, it follows that the unsigned comparison just tests the sign in reverse (positive values are LE, negative ones GE). So we can generate an unsigned comparison against an extreme value of the signed type. */ if (unsignedp && !unsignedp0) { if (val != 0) switch (code) { case LT_EXPR: case GE_EXPR: primop1 = TYPE_MIN_VALUE (type); val = 0; break; case LE_EXPR: case GT_EXPR: primop1 = TYPE_MAX_VALUE (type); val = 0; break; default: break; } type = unsigned_type (type); } if (!max_gt && !unsignedp0 && TREE_CODE (primop0) != INTEGER_CST) { /* This is the case of (char)x >?< 0x80, which people used to use expecting old C compilers to change the 0x80 into -0x80. */ if (val == boolean_false_node) warning ("comparison is always false due to limited range of data type"); if (val == boolean_true_node) warning ("comparison is always true due to limited range of data type"); } if (!min_lt && unsignedp0 && TREE_CODE (primop0) != INTEGER_CST) { /* This is the case of (unsigned char)x >?< -1 or < 0. */ if (val == boolean_false_node) warning ("comparison is always false due to limited range of data type"); if (val == boolean_true_node) warning ("comparison is always true due to limited range of data type"); } if (val != 0) { /* Don't forget to evaluate PRIMOP0 if it has side effects. */ if (TREE_SIDE_EFFECTS (primop0)) return build (COMPOUND_EXPR, TREE_TYPE (val), primop0, val); return val; } /* Value is not predetermined, but do the comparison in the type of the operand that is not constant. TYPE is already properly set. */ } else if (real1 && real2 && (TYPE_PRECISION (TREE_TYPE (primop0)) == TYPE_PRECISION (TREE_TYPE (primop1)))) type = TREE_TYPE (primop0); /* If args' natural types are both narrower than nominal type and both extend in the same manner, compare them in the type of the wider arg. Otherwise must actually extend both to the nominal common type lest different ways of extending alter the result. (eg, (short)-1 == (unsigned short)-1 should be 0.) */ else if (unsignedp0 == unsignedp1 && real1 == real2 && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr) && TYPE_PRECISION (TREE_TYPE (primop1)) < TYPE_PRECISION (*restype_ptr)) { type = common_type (TREE_TYPE (primop0), TREE_TYPE (primop1)); type = signed_or_unsigned_type (unsignedp0 || TREE_UNSIGNED (*restype_ptr), type); /* Make sure shorter operand is extended the right way to match the longer operand. */ primop0 = convert (signed_or_unsigned_type (unsignedp0, TREE_TYPE (primop0)), primop0); primop1 = convert (signed_or_unsigned_type (unsignedp1, TREE_TYPE (primop1)), primop1); } else { /* Here we must do the comparison on the nominal type using the args exactly as we received them. */ type = *restype_ptr; primop0 = op0; primop1 = op1; if (!real1 && !real2 && integer_zerop (primop1) && TREE_UNSIGNED (*restype_ptr)) { tree value = 0; switch (code) { case GE_EXPR: /* All unsigned values are >= 0, so we warn if extra warnings are requested. However, if OP0 is a constant that is >= 0, the signedness of the comparison isn't an issue, so suppress the warning. */ if (extra_warnings && ! (TREE_CODE (primop0) == INTEGER_CST && ! TREE_OVERFLOW (convert (signed_type (type), primop0)))) warning ("comparison of unsigned expression >= 0 is always true"); value = boolean_true_node; break; case LT_EXPR: if (extra_warnings && ! (TREE_CODE (primop0) == INTEGER_CST && ! TREE_OVERFLOW (convert (signed_type (type), primop0)))) warning ("comparison of unsigned expression < 0 is always false"); value = boolean_false_node; break; default: break; } if (value != 0) { /* Don't forget to evaluate PRIMOP0 if it has side effects. */ if (TREE_SIDE_EFFECTS (primop0)) return build (COMPOUND_EXPR, TREE_TYPE (value), primop0, value); return value; } } } *op0_ptr = convert (type, primop0); *op1_ptr = convert (type, primop1); *restype_ptr = boolean_type_node; return 0; } /* Prepare expr to be an argument of a TRUTH_NOT_EXPR, or validate its data type for an `if' or `while' statement or ?..: exp. This preparation consists of taking the ordinary representation of an expression expr and producing a valid tree boolean expression describing whether expr is nonzero. We could simply always do build_binary_op (NE_EXPR, expr, boolean_false_node, 1), but we optimize comparisons, &&, ||, and !. The resulting type should always be `boolean_type_node'. */ tree truthvalue_conversion (expr) tree expr; { if (TREE_CODE (expr) == ERROR_MARK) return expr; #if 0 /* This appears to be wrong for C++. */ /* These really should return error_mark_node after 2.4 is stable. But not all callers handle ERROR_MARK properly. */ switch (TREE_CODE (TREE_TYPE (expr))) { case RECORD_TYPE: error ("struct type value used where scalar is required"); return boolean_false_node; case UNION_TYPE: error ("union type value used where scalar is required"); return boolean_false_node; case ARRAY_TYPE: error ("array type value used where scalar is required"); return boolean_false_node; default: break; } #endif /* 0 */ switch (TREE_CODE (expr)) { /* It is simpler and generates better code to have only TRUTH_*_EXPR or comparison expressions as truth values at this level. */ #if 0 case COMPONENT_REF: /* A one-bit unsigned bit-field is already acceptable. */ if (1 == TREE_INT_CST_LOW (DECL_SIZE (TREE_OPERAND (expr, 1))) && TREE_UNSIGNED (TREE_OPERAND (expr, 1))) return expr; break; #endif case EQ_EXPR: /* It is simpler and generates better code to have only TRUTH_*_EXPR or comparison expressions as truth values at this level. */ #if 0 if (integer_zerop (TREE_OPERAND (expr, 1))) return build_unary_op (TRUTH_NOT_EXPR, TREE_OPERAND (expr, 0), 0); #endif case NE_EXPR: case LE_EXPR: case GE_EXPR: case LT_EXPR: case GT_EXPR: case TRUTH_ANDIF_EXPR: case TRUTH_ORIF_EXPR: case TRUTH_AND_EXPR: case TRUTH_OR_EXPR: case TRUTH_XOR_EXPR: case TRUTH_NOT_EXPR: TREE_TYPE (expr) = boolean_type_node; return expr; case ERROR_MARK: return expr; case INTEGER_CST: return integer_zerop (expr) ? boolean_false_node : boolean_true_node; case REAL_CST: return real_zerop (expr) ? boolean_false_node : boolean_true_node; case ADDR_EXPR: /* If we are taking the address of a external decl, it might be zero if it is weak, so we cannot optimize. */ if (TREE_CODE_CLASS (TREE_CODE (TREE_OPERAND (expr, 0))) == 'd' && DECL_EXTERNAL (TREE_OPERAND (expr, 0))) break; if (TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 0))) return build (COMPOUND_EXPR, boolean_type_node, TREE_OPERAND (expr, 0), boolean_true_node); else return boolean_true_node; case COMPLEX_EXPR: return build_binary_op ((TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1)) ? TRUTH_OR_EXPR : TRUTH_ORIF_EXPR), truthvalue_conversion (TREE_OPERAND (expr, 0)), truthvalue_conversion (TREE_OPERAND (expr, 1)), 0); case NEGATE_EXPR: case ABS_EXPR: case FLOAT_EXPR: case FFS_EXPR: /* These don't change whether an object is non-zero or zero. */ return truthvalue_conversion (TREE_OPERAND (expr, 0)); case LROTATE_EXPR: case RROTATE_EXPR: /* These don't change whether an object is zero or non-zero, but we can't ignore them if their second arg has side-effects. */ if (TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1))) return build (COMPOUND_EXPR, boolean_type_node, TREE_OPERAND (expr, 1), truthvalue_conversion (TREE_OPERAND (expr, 0))); else return truthvalue_conversion (TREE_OPERAND (expr, 0)); case COND_EXPR: /* Distribute the conversion into the arms of a COND_EXPR. */ return fold (build (COND_EXPR, boolean_type_node, TREE_OPERAND (expr, 0), truthvalue_conversion (TREE_OPERAND (expr, 1)), truthvalue_conversion (TREE_OPERAND (expr, 2)))); case CONVERT_EXPR: /* Don't cancel the effect of a CONVERT_EXPR from a REFERENCE_TYPE, since that affects how `default_conversion' will behave. */ if (TREE_CODE (TREE_TYPE (expr)) == REFERENCE_TYPE || TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == REFERENCE_TYPE) break; /* fall through... */ case NOP_EXPR: /* If this is widening the argument, we can ignore it. */ if (TYPE_PRECISION (TREE_TYPE (expr)) >= TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (expr, 0)))) return truthvalue_conversion (TREE_OPERAND (expr, 0)); break; case MINUS_EXPR: /* With IEEE arithmetic, x - x may not equal 0, so we can't optimize this case. */ if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT && TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE) break; /* fall through... */ case BIT_XOR_EXPR: /* This and MINUS_EXPR can be changed into a comparison of the two objects. */ if (TREE_TYPE (TREE_OPERAND (expr, 0)) == TREE_TYPE (TREE_OPERAND (expr, 1))) return build_binary_op (NE_EXPR, TREE_OPERAND (expr, 0), TREE_OPERAND (expr, 1), 1); return build_binary_op (NE_EXPR, TREE_OPERAND (expr, 0), fold (build1 (NOP_EXPR, TREE_TYPE (TREE_OPERAND (expr, 0)), TREE_OPERAND (expr, 1))), 1); case BIT_AND_EXPR: if (integer_onep (TREE_OPERAND (expr, 1)) && TREE_TYPE (expr) != boolean_type_node) /* Using convert here would cause infinite recursion. */ return build1 (NOP_EXPR, boolean_type_node, expr); break; case MODIFY_EXPR: if (warn_parentheses && C_EXP_ORIGINAL_CODE (expr) == MODIFY_EXPR) warning ("suggest parentheses around assignment used as truth value"); break; default: break; } if (TREE_CODE (TREE_TYPE (expr)) == COMPLEX_TYPE) { tree tem = save_expr (expr); return (build_binary_op ((TREE_SIDE_EFFECTS (expr) ? TRUTH_OR_EXPR : TRUTH_ORIF_EXPR), truthvalue_conversion (build_unary_op (REALPART_EXPR, tem, 0)), truthvalue_conversion (build_unary_op (IMAGPART_EXPR, tem, 0)), 0)); } return build_binary_op (NE_EXPR, expr, integer_zero_node, 1); } #if USE_CPPLIB /* Read the rest of a #-directive from input stream FINPUT. In normal use, the directive name and the white space after it have already been read, so they won't be included in the result. We allow for the fact that the directive line may contain a newline embedded within a character or string literal which forms a part of the directive. The value is a string in a reusable buffer. It remains valid only until the next time this function is called. */ unsigned char *yy_cur, *yy_lim; #define GETC() (yy_cur < yy_lim ? *yy_cur++ : yy_get_token ()) #define UNGETC(c) ((c) == EOF ? 0 : yy_cur--) int yy_get_token () { for (;;) { parse_in.limit = parse_in.token_buffer; cpp_token = cpp_get_token (&parse_in); if (cpp_token == CPP_EOF) return -1; yy_lim = CPP_PWRITTEN (&parse_in); yy_cur = parse_in.token_buffer; if (yy_cur < yy_lim) return *yy_cur++; } } char * get_directive_line () { static char *directive_buffer = NULL; static unsigned buffer_length = 0; register char *p; register char *buffer_limit; register int looking_for = 0; register int char_escaped = 0; if (buffer_length == 0) { directive_buffer = (char *)xmalloc (128); buffer_length = 128; } buffer_limit = &directive_buffer[buffer_length]; for (p = directive_buffer; ; ) { int c; /* Make buffer bigger if it is full. */ if (p >= buffer_limit) { register unsigned bytes_used = (p - directive_buffer); buffer_length *= 2; directive_buffer = (char *)xrealloc (directive_buffer, buffer_length); p = &directive_buffer[bytes_used]; buffer_limit = &directive_buffer[buffer_length]; } c = GETC (); /* Discard initial whitespace. */ if ((c == ' ' || c == '\t') && p == directive_buffer) continue; /* Detect the end of the directive. */ if (c == '\n' && looking_for == 0) { UNGETC (c); c = '\0'; } *p++ = c; if (c == 0) return directive_buffer; /* Handle string and character constant syntax. */ if (looking_for) { if (looking_for == c && !char_escaped) looking_for = 0; /* Found terminator... stop looking. */ } else if (c == '\'' || c == '"') looking_for = c; /* Don't stop buffering until we see another another one of these (or an EOF). */ /* Handle backslash. */ char_escaped = (c == '\\' && ! char_escaped); } } #else /* Read the rest of a #-directive from input stream FINPUT. In normal use, the directive name and the white space after it have already been read, so they won't be included in the result. We allow for the fact that the directive line may contain a newline embedded within a character or string literal which forms a part of the directive. The value is a string in a reusable buffer. It remains valid only until the next time this function is called. The terminating character ('\n' or EOF) is left in FINPUT for the caller to re-read. */ char * get_directive_line (finput) register FILE *finput; { static char *directive_buffer = NULL; static unsigned buffer_length = 0; register char *p; register char *buffer_limit; register int looking_for = 0; register int char_escaped = 0; if (buffer_length == 0) { directive_buffer = (char *)xmalloc (128); buffer_length = 128; } buffer_limit = &directive_buffer[buffer_length]; for (p = directive_buffer; ; ) { int c; /* Make buffer bigger if it is full. */ if (p >= buffer_limit) { register unsigned bytes_used = (p - directive_buffer); buffer_length *= 2; directive_buffer = (char *)xrealloc (directive_buffer, buffer_length); p = &directive_buffer[bytes_used]; buffer_limit = &directive_buffer[buffer_length]; } c = getc (finput); /* Discard initial whitespace. */ if ((c == ' ' || c == '\t') && p == directive_buffer) continue; /* Detect the end of the directive. */ if (looking_for == 0 && (c == '\n' || c == EOF)) { ungetc (c, finput); c = '\0'; } *p++ = c; if (c == 0) return directive_buffer; /* Handle string and character constant syntax. */ if (looking_for) { if (looking_for == c && !char_escaped) looking_for = 0; /* Found terminator... stop looking. */ } else if (c == '\'' || c == '"') looking_for = c; /* Don't stop buffering until we see another one of these (or an EOF). */ /* Handle backslash. */ char_escaped = (c == '\\' && ! char_escaped); } } #endif /* !USE_CPPLIB */ /* Make a variant type in the proper way for C/C++, propagating qualifiers down to the element type of an array. */ tree c_build_qualified_type (type, type_quals) tree type; int type_quals; { /* A restrict-qualified pointer type must be a pointer to object or incomplete type. Note that the use of POINTER_TYPE_P also allows REFERENCE_TYPEs, which is appropriate for C++. Unfortunately, the C++ front-end also use POINTER_TYPE for pointer-to-member values, so even though it should be illegal to use `restrict' with such an entity we don't flag that here. Thus, special case code for that case is required in the C++ front-end. */ if ((type_quals & TYPE_QUAL_RESTRICT) && (!POINTER_TYPE_P (type) || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type)))) { error ("invalid use of `restrict'"); type_quals &= ~TYPE_QUAL_RESTRICT; } if (TREE_CODE (type) == ARRAY_TYPE) return build_array_type (c_build_qualified_type (TREE_TYPE (type), type_quals), TYPE_DOMAIN (type)); return build_qualified_type (type, type_quals); } /* Apply the TYPE_QUALS to the new DECL. */ void c_apply_type_quals_to_decl (type_quals, decl) int type_quals; tree decl; { if (type_quals & TYPE_QUAL_CONST) TREE_READONLY (decl) = 1; if (type_quals & TYPE_QUAL_VOLATILE) { TREE_SIDE_EFFECTS (decl) = 1; TREE_THIS_VOLATILE (decl) = 1; } if (type_quals & TYPE_QUAL_RESTRICT) { if (!TREE_TYPE (decl) || !POINTER_TYPE_P (TREE_TYPE (decl)) || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (TREE_TYPE (decl)))) error ("invalid use of `restrict'"); else if (flag_strict_aliasing) { /* No two restricted pointers can point at the same thing. However, a restricted pointer can point at the same thing as an unrestricted pointer, if that unrestricted pointer is based on the restricted pointer. So, we make the alias set for the restricted pointer a subset of the alias set for the type pointed to by the type of the decl. */ int pointed_to_alias_set = get_alias_set (TREE_TYPE (TREE_TYPE (decl))); if (!pointed_to_alias_set) /* It's not legal to make a subset of alias set zero. */ ; else { DECL_POINTER_ALIAS_SET (decl) = new_alias_set (); record_alias_subset (pointed_to_alias_set, DECL_POINTER_ALIAS_SET (decl)); } } } } /* T is an expression with pointer type. Find the DECL on which this expression is based. (For example, in `a[i]' this would be `a'.) If there is no such DECL, or a unique decl cannot be determined, NULL_TREE is retured. */ static tree c_find_base_decl (t) tree t; { int i; tree decl; if (t == NULL_TREE || t == error_mark_node) return NULL_TREE; if (!POINTER_TYPE_P (TREE_TYPE (t))) return NULL_TREE; decl = NULL_TREE; if (TREE_CODE (t) == FIELD_DECL || TREE_CODE (t) == PARM_DECL || TREE_CODE (t) == VAR_DECL) /* Aha, we found a pointer-typed declaration. */ return t; /* It would be nice to deal with COMPONENT_REFs here. If we could tell that `a' and `b' were the same, then `a->f' and `b->f' are also the same. */ /* Handle general expressions. */ switch (TREE_CODE_CLASS (TREE_CODE (t))) { case '1': case '2': case '3': for (i = tree_code_length [(int) TREE_CODE (t)]; --i >= 0;) { tree d = c_find_base_decl (TREE_OPERAND (t, i)); if (d) { if (!decl) decl = d; else if (d && d != decl) /* Two different declarations. That's confusing; let's just assume we don't know what's going on. */ decl = NULL_TREE; } } break; default: break; } return decl; } /* Return the typed-based alias set for T, which may be an expression or a type. */ int c_get_alias_set (t) tree t; { tree type; tree u; if (t == error_mark_node) return 0; type = (TREE_CODE_CLASS (TREE_CODE (t)) == 't') ? t : TREE_TYPE (t); if (type == error_mark_node) return 0; /* Deal with special cases first; for certain kinds of references we're interested in more than just the type. */ if (TREE_CODE (t) == BIT_FIELD_REF) /* Perhaps reads and writes to this piece of data alias fields neighboring the bitfield. Perhaps that's impossible. For now, let's just assume that bitfields can alias everything, which is the conservative assumption. */ return 0; /* Permit type-punning when accessing a union, provided the access is directly through the union. For example, this code does not permit taking the address of a union member and then storing through it. Even the type-punning allowed here is a GCC extension, albeit a common and useful one; the C standard says that such accesses have implementation-defined behavior. */ for (u = t; TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF; u = TREE_OPERAND (u, 0)) if (TREE_CODE (u) == COMPONENT_REF && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE) return 0; if (TREE_CODE (t) == INDIRECT_REF) { /* Check for accesses through restrict-qualified pointers. */ tree decl = c_find_base_decl (TREE_OPERAND (t, 0)); if (decl && DECL_POINTER_ALIAS_SET_KNOWN_P (decl)) /* We use the alias set indicated in the declaration. */ return DECL_POINTER_ALIAS_SET (decl); } /* From here on, only the type matters. */ if (TREE_CODE (t) == COMPONENT_REF && DECL_BIT_FIELD_TYPE (TREE_OPERAND (t, 1))) /* Since build_modify_expr calls get_unwidened for stores to component references, the type of a bit field can be changed from (say) `unsigned int : 16' to `unsigned short' or from `enum E : 16' to `short'. We want the real type of the bit-field in this case, not some the integral equivalent. */ type = DECL_BIT_FIELD_TYPE (TREE_OPERAND (t, 1)); if (TYPE_ALIAS_SET_KNOWN_P (type)) /* If we've already calculated the value, just return it. */ return TYPE_ALIAS_SET (type); else if (TYPE_MAIN_VARIANT (type) != type) /* The C standard specifically allows aliasing between cv-qualified variants of types. */ TYPE_ALIAS_SET (type) = c_get_alias_set (TYPE_MAIN_VARIANT (type)); else if (TREE_CODE (type) == INTEGER_TYPE) { tree signed_variant; /* The C standard specifically allows aliasing between signed and unsigned variants of the same type. We treat the signed variant as canonical. */ signed_variant = signed_type (type); if (signed_variant != type) TYPE_ALIAS_SET (type) = c_get_alias_set (signed_variant); else if (signed_variant == signed_char_type_node) /* The C standard guarantess that any object may be accessed via an lvalue that has character type. We don't have to check for unsigned_char_type_node or char_type_node because we are specifically looking at the signed variant. */ TYPE_ALIAS_SET (type) = 0; } else if (TREE_CODE (type) == ARRAY_TYPE) /* Anything that can alias one of the array elements can alias the entire array as well. */ TYPE_ALIAS_SET (type) = c_get_alias_set (TREE_TYPE (type)); else if (TREE_CODE (type) == FUNCTION_TYPE) /* There are no objects of FUNCTION_TYPE, so there's no point in using up an alias set for them. (There are, of course, pointers and references to functions, but that's different.) */ TYPE_ALIAS_SET (type) = 0; else if (TREE_CODE (type) == RECORD_TYPE || TREE_CODE (type) == UNION_TYPE) /* If TYPE is a struct or union type then we're reading or writing an entire struct. Thus, we don't know anything about aliasing. (In theory, such an access can only alias objects whose type is the same as one of the fields, recursively, but we don't yet make any use of that information.) */ TYPE_ALIAS_SET (type) = 0; else if (TREE_CODE (type) == POINTER_TYPE || TREE_CODE (type) == REFERENCE_TYPE) { tree t; /* Unfortunately, there is no canonical form of a pointer type. In particular, if we have `typedef int I', then `int *', and `I *' are different types. So, we have to pick a canonical representative. We do this below. Technically, this approach is actually more conservative that it needs to be. In particular, `const int *' and `int *' chould be in different alias sets, according to the C and C++ standard, since their types are not the same, and so, technically, an `int **' and `const int **' cannot point at the same thing. But, the standard is wrong. In particular, this code is legal C++: int *ip; int **ipp = &ip; const int* const* cipp = &ip; And, it doesn't make sense for that to be legal unless you can dereference IPP and CIPP. So, we ignore cv-qualifiers on the pointed-to types. This issue has been reported to the C++ committee. */ t = TYPE_MAIN_VARIANT (TREE_TYPE (type)); t = ((TREE_CODE (type) == POINTER_TYPE) ? build_pointer_type (t) : build_reference_type (t)); if (t != type) TYPE_ALIAS_SET (type) = c_get_alias_set (t); } if (!TYPE_ALIAS_SET_KNOWN_P (type)) { /* Types that are not allocated on the permanent obstack are not placed in the type hash table. Thus, there can be multiple copies of identical types in local scopes. In the long run, all types should be permanent. */ if (! TREE_PERMANENT (type)) TYPE_ALIAS_SET (type) = 0; else /* TYPE is something we haven't seen before. Put it in a new alias set. */ TYPE_ALIAS_SET (type) = new_alias_set (); } return TYPE_ALIAS_SET (type); }