function_hooks: update comment explaining various function hooks

[smatch.git] / parse.c

/*
 * Stupid C parser, version 1e-6.
 *
 * Let's see how hard this is to do.
 *
 * Copyright (C) 2003 Transmeta Corp.
 *               2003-2004 Linus Torvalds
 * Copyright (C) 2004 Christopher Li
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <unistd.h>
#include <fcntl.h>
#include <limits.h>

#include "lib.h"
#include "allocate.h"
#include "token.h"
#include "parse.h"
#include "symbol.h"
#include "scope.h"
#include "expression.h"
#include "target.h"

static struct symbol_list **function_symbol_list;
struct symbol_list *function_computed_target_list;
struct statement_list *function_computed_goto_list;

static struct token *statement(struct token *token, struct statement **tree);
static struct token *handle_attributes(struct token *token, struct decl_state *ctx);

typedef struct token *declarator_t(struct token *, struct symbol *, struct decl_state *);
static declarator_t
        struct_specifier, union_specifier, enum_specifier,
        attribute_specifier, typeof_specifier,
        storage_specifier, thread_specifier;
static declarator_t generic_qualifier;
static declarator_t autotype_specifier;

static struct token *parse_if_statement(struct token *token, struct statement *stmt);
static struct token *parse_return_statement(struct token *token, struct statement *stmt);
static struct token *parse_loop_iterator(struct token *token, struct statement *stmt);
static struct token *parse_default_statement(struct token *token, struct statement *stmt);
static struct token *parse_case_statement(struct token *token, struct statement *stmt);
static struct token *parse_switch_statement(struct token *token, struct statement *stmt);
static struct token *parse_for_statement(struct token *token, struct statement *stmt);
static struct token *parse_while_statement(struct token *token, struct statement *stmt);
static struct token *parse_do_statement(struct token *token, struct statement *stmt);
static struct token *parse_goto_statement(struct token *token, struct statement *stmt);
static struct token *parse_context_statement(struct token *token, struct statement *stmt);
static struct token *parse_range_statement(struct token *token, struct statement *stmt);
static struct token *parse_asm_statement(struct token *token, struct statement *stmt);
static struct token *toplevel_asm_declaration(struct token *token, struct symbol_list **list);
static struct token *parse_static_assert(struct token *token, struct symbol_list **unused);

typedef struct token *attr_t(struct token *, struct symbol *,
                             struct decl_state *);

static attr_t
        attribute_packed, attribute_aligned, attribute_modifier,
        attribute_function,
        attribute_bitwise,
        attribute_address_space, attribute_context,
        attribute_designated_init,
        attribute_transparent_union, ignore_attribute,
        attribute_mode, attribute_force;

typedef struct symbol *to_mode_t(struct symbol *);

static to_mode_t
        to_QI_mode, to_HI_mode, to_SI_mode, to_DI_mode, to_TI_mode;
static to_mode_t to_pointer_mode, to_word_mode;

enum {
        Set_T = 1,
        Set_S = 2,
        Set_Char = 4,
        Set_Int = 8,
        Set_Double = 16,
        Set_Float = 32,
        Set_Signed = 64,
        Set_Unsigned = 128,
        Set_Short = 256,
        Set_Long = 512,
        Set_Vlong = 1024,
        Set_Int128 = 2048,
        Set_Any = Set_T | Set_Short | Set_Long | Set_Signed | Set_Unsigned
};

enum {
        CInt = 0, CSInt, CUInt, CReal,
};

static void asm_modifier(struct token *token, unsigned long *mods, unsigned long mod)
{
        if (*mods & mod)
                warning(token->pos, "duplicated asm modifier");
        *mods |= mod;
}

static struct symbol_op typedef_op = {
        .type = KW_MODIFIER,
        .declarator = storage_specifier,
};

static struct symbol_op inline_op = {
        .type = KW_MODIFIER,
        .declarator = generic_qualifier,
        .asm_modifier = asm_modifier,
};

static struct symbol_op noreturn_op = {
        .type = KW_MODIFIER,
        .declarator = generic_qualifier,
};

static declarator_t alignas_specifier;
static struct symbol_op alignas_op = {
        .type = KW_MODIFIER,
        .declarator = alignas_specifier,
};

static struct symbol_op auto_op = {
        .type = KW_MODIFIER,
        .declarator = storage_specifier,
};

static struct symbol_op register_op = {
        .type = KW_MODIFIER,
        .declarator = storage_specifier,
};

static struct symbol_op static_op = {
        .type = KW_MODIFIER|KW_STATIC,
        .declarator = storage_specifier,
};

static struct symbol_op extern_op = {
        .type = KW_MODIFIER,
        .declarator = storage_specifier,
};

static struct symbol_op thread_op = {
        .type = KW_MODIFIER,
        .declarator = thread_specifier,
};

static struct symbol_op const_op = {
        .type = KW_QUALIFIER,
        .declarator = generic_qualifier,
};

static struct symbol_op volatile_op = {
        .type = KW_QUALIFIER,
        .declarator = generic_qualifier,
        .asm_modifier = asm_modifier,
};

static struct symbol_op restrict_op = {
        .type = KW_QUALIFIER,
        .declarator = generic_qualifier,
};

static struct symbol_op atomic_op = {
        .type = KW_QUALIFIER,
        .declarator = generic_qualifier,
};

static struct symbol_op typeof_op = {
        .type = KW_SPECIFIER,
        .declarator = typeof_specifier,
        .test = Set_Any,
        .set = Set_S|Set_T,
};

static struct symbol_op autotype_op = {
        .type = KW_SPECIFIER,
        .declarator = autotype_specifier,
        .test = Set_Any,
        .set = Set_S|Set_T,
};

static struct symbol_op attribute_op = {
        .type = KW_ATTRIBUTE,
        .declarator = attribute_specifier,
};

static struct symbol_op struct_op = {
        .type = KW_SPECIFIER,
        .declarator = struct_specifier,
        .test = Set_Any,
        .set = Set_S|Set_T,
};

static struct symbol_op union_op = {
        .type = KW_SPECIFIER,
        .declarator = union_specifier,
        .test = Set_Any,
        .set = Set_S|Set_T,
};

static struct symbol_op enum_op = {
        .type = KW_SPECIFIER,
        .declarator = enum_specifier,
        .test = Set_Any,
        .set = Set_S|Set_T,
};

static struct symbol_op spec_op = {
        .type = KW_SPECIFIER | KW_EXACT,
        .test = Set_Any,
        .set = Set_S|Set_T,
};

static struct symbol_op char_op = {
        .type = KW_SPECIFIER,
        .test = Set_T|Set_Long|Set_Short,
        .set = Set_T|Set_Char,
        .class = CInt,
};

static struct symbol_op int_op = {
        .type = KW_SPECIFIER,
        .test = Set_T,
        .set = Set_T|Set_Int,
};

static struct symbol_op double_op = {
        .type = KW_SPECIFIER,
        .test = Set_T|Set_Signed|Set_Unsigned|Set_Short|Set_Vlong,
        .set = Set_T|Set_Double,
        .class = CReal,
};

static struct symbol_op float_op = {
        .type = KW_SPECIFIER,
        .test = Set_T|Set_Signed|Set_Unsigned|Set_Short|Set_Long,
        .set = Set_T|Set_Float,
        .class = CReal,
};

static struct symbol_op short_op = {
        .type = KW_SPECIFIER,
        .test = Set_S|Set_Char|Set_Float|Set_Double|Set_Long|Set_Short,
        .set = Set_Short,
};

static struct symbol_op signed_op = {
        .type = KW_SPECIFIER,
        .test = Set_S|Set_Float|Set_Double|Set_Signed|Set_Unsigned,
        .set = Set_Signed,
        .class = CSInt,
};

static struct symbol_op unsigned_op = {
        .type = KW_SPECIFIER,
        .test = Set_S|Set_Float|Set_Double|Set_Signed|Set_Unsigned,
        .set = Set_Unsigned,
        .class = CUInt,
};

static struct symbol_op long_op = {
        .type = KW_SPECIFIER,
        .test = Set_S|Set_Char|Set_Float|Set_Short|Set_Vlong,
        .set = Set_Long,
};

static struct symbol_op int128_op = {
        .type = KW_SPECIFIER,
        .test = Set_S|Set_T|Set_Char|Set_Short|Set_Int|Set_Float|Set_Double|Set_Long|Set_Vlong|Set_Int128,
        .set =  Set_T|Set_Int128|Set_Vlong,
        .class = CInt,
};

static struct symbol_op if_op = {
        .statement = parse_if_statement,
};

static struct symbol_op return_op = {
        .statement = parse_return_statement,
};

static struct symbol_op loop_iter_op = {
        .statement = parse_loop_iterator,
};

static struct symbol_op default_op = {
        .statement = parse_default_statement,
};

static struct symbol_op case_op = {
        .statement = parse_case_statement,
};

static struct symbol_op switch_op = {
        .statement = parse_switch_statement,
};

static struct symbol_op for_op = {
        .statement = parse_for_statement,
};

static struct symbol_op while_op = {
        .statement = parse_while_statement,
};

static struct symbol_op do_op = {
        .statement = parse_do_statement,
};

static struct symbol_op goto_op = {
        .statement = parse_goto_statement,
};

static struct symbol_op __context___op = {
        .statement = parse_context_statement,
        .attribute = attribute_context,
};

static struct symbol_op range_op = {
        .statement = parse_range_statement,
};

static struct symbol_op asm_op = {
        .type = KW_ASM,
        .statement = parse_asm_statement,
        .toplevel = toplevel_asm_declaration,
};

static struct symbol_op static_assert_op = {
        .toplevel = parse_static_assert,
};

static struct symbol_op packed_op = {
        .attribute = attribute_packed,
};

static struct symbol_op aligned_op = {
        .attribute = attribute_aligned,
};

static struct symbol_op attr_mod_op = {
        .attribute = attribute_modifier,
};

static struct symbol_op attr_fun_op = {
        .attribute = attribute_function,
};

static struct symbol_op attr_bitwise_op = {
        .attribute = attribute_bitwise,
};

static struct symbol_op attr_force_op = {
        .attribute = attribute_force,
};

static struct symbol_op address_space_op = {
        .attribute = attribute_address_space,
};

static struct symbol_op mode_op = {
        .attribute = attribute_mode,
};

static struct symbol_op context_op = {
        .attribute = attribute_context,
};

static struct symbol_op designated_init_op = {
        .attribute = attribute_designated_init,
};

static struct symbol_op transparent_union_op = {
        .attribute = attribute_transparent_union,
};

static struct symbol_op ignore_attr_op = {
        .attribute = ignore_attribute,
};

static struct symbol_op mode_QI_op = {
        .type = KW_MODE,
        .to_mode = to_QI_mode
};

static struct symbol_op mode_HI_op = {
        .type = KW_MODE,
        .to_mode = to_HI_mode
};

static struct symbol_op mode_SI_op = {
        .type = KW_MODE,
        .to_mode = to_SI_mode
};

static struct symbol_op mode_DI_op = {
        .type = KW_MODE,
        .to_mode = to_DI_mode
};

static struct symbol_op mode_TI_op = {
        .type = KW_MODE,
        .to_mode = to_TI_mode
};

static struct symbol_op mode_pointer_op = {
        .type = KW_MODE,
        .to_mode = to_pointer_mode
};

static struct symbol_op mode_word_op = {
        .type = KW_MODE,
        .to_mode = to_word_mode
};

/*
 * Define the keyword and their effects.
 * The entries in the 'typedef' and put in NS_TYPEDEF and
 * are automatically set as reserved keyword while the ones
 * in the 'keyword' table are just put in NS_KEYWORD.
 *
 * The entries are added via the 3 macros:
 *   N() for entries with "name" only,
 *   D() for entries with "name" & "__name__",
 *   A() for entries with "name", "__name" & "__name__",
 *   U() for entries with "__name" & "__name__".
 */
static struct init_keyword {
        const char *name;
        struct symbol_op *op;
        struct symbol *type;
        unsigned long mods;
} typedefs[] = {
#define N(I, O,...)     { I, O,##__VA_ARGS__ }
#define D(I, O,...)     N(I,O,##__VA_ARGS__ ),          \
                        N("__" I "__",O,##__VA_ARGS__)
#define A(I, O,...)     N(I,O,##__VA_ARGS__ ),          \
                        N("__" I,O,##__VA_ARGS__),      \
                        N("__" I "__",O,##__VA_ARGS__)
#define U(I, O,...)     N("__" I,O,##__VA_ARGS__),      \
                        N("__" I "__",O,##__VA_ARGS__)
        /* Storage classes */
        N("auto",               &auto_op,       .mods = MOD_AUTO),
        N("register",           &register_op,   .mods = MOD_REGISTER),
        N("static",             &static_op,     .mods = MOD_STATIC),
        N("extern",             &extern_op,     .mods = MOD_EXTERN),
        N("__thread",           &thread_op),
        N("_Thread_local",      &thread_op),

        A("inline",             &inline_op,     .mods = MOD_INLINE),

        /* Typedef ... */
        N("typedef",            &typedef_op,    .mods = MOD_USERTYPE),
        A("typeof",             &typeof_op),
        N("__auto_type",        &autotype_op),

        /* Type qualifiers */
        A("const",              &const_op,      .mods = MOD_CONST),
        A("volatile",           &volatile_op,   .mods = MOD_VOLATILE),
        A("restrict",           &restrict_op,   .mods = MOD_RESTRICT),

        N("_Atomic",            &atomic_op,     .mods = MOD_ATOMIC),
        N("_Noreturn",          &noreturn_op,   .mods = MOD_NORETURN),
        N("_Alignas",           &alignas_op),

        U("attribute",          &attribute_op),

        /* Type specifiers */
        N("struct",             &struct_op),
        N("union",              &union_op),
        N("enum",               &enum_op),

        N("void",               &spec_op,       .type = &void_ctype),
        N("char",               &char_op),
        N("short",              &short_op),
        N("int",                &int_op),
        N("long",               &long_op),
        N("float",              &float_op),
        N("double",             &double_op),
        A("signed",             &signed_op),
        N("unsigned",           &unsigned_op),
        N("__int128",           &int128_op),
        N("_Bool",              &spec_op,       .type = &bool_ctype),

        /* Predeclared types */
        N("__builtin_va_list",  &spec_op,       .type = &ptr_ctype),
        N("__builtin_ms_va_list",&spec_op,      .type = &ptr_ctype),
        N("__int128_t",         &spec_op,       .type = &sint128_ctype),
        N("__uint128_t",        &spec_op,       .type = &uint128_ctype),
        N("_Float32",           &spec_op,       .type = &float32_ctype),
        N("_Float32x",          &spec_op,       .type = &float32x_ctype),
        N("_Float64",           &spec_op,       .type = &float64_ctype),
        N("_Float64x",          &spec_op,       .type = &float64x_ctype),
        N("_Float128",          &spec_op,       .type = &float128_ctype),
}, keywords[] = {
        /* Statements */
        N("if",                 &if_op),
        N("return",             &return_op),
        N("break",              &loop_iter_op),
        N("continue",           &loop_iter_op),
        N("default",            &default_op),
        N("case",               &case_op),
        N("switch",             &switch_op),
        N("for",                &for_op),
        N("while",              &while_op),
        N("do",                 &do_op),
        N("goto",               &goto_op),
        A("asm",                &asm_op),
        N("context",            &context_op),
        N("__context__",        &__context___op),
        N("__range__",          &range_op),
        N("_Static_assert",     &static_assert_op),

        /* Attributes */
        D("packed",             &packed_op),
        D("aligned",            &aligned_op),
        D("nocast",             &attr_mod_op,           .mods = MOD_NOCAST),
        D("noderef",            &attr_mod_op,           .mods = MOD_NODEREF),
        D("safe",               &attr_mod_op,           .mods = MOD_SAFE),
        D("unused",             &attr_mod_op,           .mods = MOD_UNUSED),
        D("externally_visible", &attr_mod_op,           .mods = MOD_EXT_VISIBLE),
        D("force",              &attr_force_op),
        D("bitwise",            &attr_bitwise_op,       .mods = MOD_BITWISE),
        D("address_space",      &address_space_op),
        D("designated_init",    &designated_init_op),
        D("transparent_union",  &transparent_union_op),
        D("noreturn",           &attr_fun_op,           .mods = MOD_NORETURN),
        D("pure",               &attr_fun_op,           .mods = MOD_PURE),
        A("const",              &attr_fun_op,           .mods = MOD_PURE),
        D("gnu_inline",         &attr_fun_op,           .mods = MOD_GNU_INLINE),

        /* Modes */
        D("mode",               &mode_op),
        D("QI",                 &mode_QI_op),
        D("HI",                 &mode_HI_op),
        D("SI",                 &mode_SI_op),
        D("DI",                 &mode_DI_op),
        D("TI",                 &mode_TI_op),
        D("byte",               &mode_QI_op),
        D("pointer",            &mode_pointer_op),
        D("word",               &mode_word_op),
};


static const char *ignored_attributes[] = {

#define GCC_ATTR(x)             \
        STRINGIFY(x),           \
        STRINGIFY(__##x##__),

#include "gcc-attr-list.h"

#undef GCC_ATTR

        "bounded",
        "__bounded__",
        "__noclone",
        "__nonnull",
        "__nothrow",
};


static void init_keyword(int stream, struct init_keyword *kw, enum namespace ns)
{
        struct symbol *sym = create_symbol(stream, kw->name, SYM_KEYWORD, ns);
        sym->ident->keyword = 1;
        sym->ident->reserved |= (ns == NS_TYPEDEF);
        sym->ctype.modifiers = kw->mods;
        sym->ctype.base_type = kw->type;
        sym->op = kw->op;
}

void init_parser(int stream)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(typedefs); i++)
                init_keyword(stream, &typedefs[i], NS_TYPEDEF);
        for (i = 0; i < ARRAY_SIZE(keywords); i++)
                init_keyword(stream, &keywords[i], NS_KEYWORD);

        for (i = 0; i < ARRAY_SIZE(ignored_attributes); i++) {
                const char * name = ignored_attributes[i];
                struct symbol *sym = create_symbol(stream, name, SYM_KEYWORD,
                                                   NS_KEYWORD);
                if (!sym->op) {
                        sym->ident->keyword = 1;
                        sym->op = &ignore_attr_op;
                }
        }
}


static struct token *skip_to(struct token *token, int op)
{
        while (!match_op(token, op) && !eof_token(token))
                token = token->next;
        return token;
}

static struct token bad_token = { .pos.type = TOKEN_BAD };
struct token *expect(struct token *token, int op, const char *where)
{
        if (!match_op(token, op)) {
                if (token != &bad_token) {
                        bad_token.next = token;
                        sparse_error(token->pos, "Expected %s %s", show_special(op), where);
                        sparse_error(token->pos, "got %s", show_token(token));
                }
                if (op == ';')
                        return skip_to(token, op);
                return &bad_token;
        }
        return token->next;
}

///
// issue an error message on new parsing errors
// @token: the current token
// @errmsg: the error message
// If the current token is from a previous error, an error message
// has already been issued, so nothing more is done.
// Otherwise, @errmsg is displayed followed by the current token.
static void unexpected(struct token *token, const char *errmsg)
{
        if (token == &bad_token)
                return;
        sparse_error(token->pos, "%s", errmsg);
        sparse_error(token->pos, "got %s", show_token(token));
}

// Add a symbol to the list of function-local symbols
static void fn_local_symbol(struct symbol *sym)
{
        if (function_symbol_list)
                add_symbol(function_symbol_list, sym);
}

struct statement *alloc_statement(struct position pos, int type)
{
        struct statement *stmt = __alloc_statement(0);
        stmt->type = type;
        stmt->pos = pos;
        return stmt;
}

static struct token *struct_declaration_list(struct token *token, struct symbol_list **list);

static void apply_ctype(struct position pos, struct ctype *dst, struct ctype *src);

static void apply_modifiers(struct position pos, struct decl_state *ctx)
{
        struct symbol *ctype;
        if (!ctx->mode)
                return;
        ctype = ctx->mode->to_mode(ctx->ctype.base_type);
        if (!ctype)
                sparse_error(pos, "don't know how to apply mode to %s",
                                show_typename(ctx->ctype.base_type));
        else
                ctx->ctype.base_type = ctype;
        
}

static struct symbol * alloc_indirect_symbol(struct position pos, struct ctype *ctype, int type)
{
        struct symbol *sym = alloc_symbol(pos, type);

        sym->ctype.base_type = ctype->base_type;
        sym->ctype.modifiers = ctype->modifiers;

        ctype->base_type = sym;
        ctype->modifiers = 0;
        return sym;
}

/*
 * NOTE! NS_LABEL is not just a different namespace,
 * it also ends up using function scope instead of the
 * regular symbol scope.
 */
struct symbol *label_symbol(struct token *token, int used)
{
        struct symbol *sym = lookup_symbol(token->ident, NS_LABEL);
        if (!sym) {
                sym = alloc_symbol(token->pos, SYM_LABEL);
                bind_symbol(sym, token->ident, NS_LABEL);
                if (used)
                        sym->used = 1;
                fn_local_symbol(sym);
        }
        return sym;
}

static struct token *struct_union_enum_specifier(enum type type,
        struct token *token, struct decl_state *ctx,
        struct token *(*parse)(struct token *, struct symbol *))
{
        struct decl_state attr = { };
        struct symbol *sym;
        struct position *repos;

        token = handle_attributes(token, &attr);
        if (token_type(token) == TOKEN_IDENT) {
                sym = lookup_symbol(token->ident, NS_STRUCT);
                if (!sym ||
                    (is_outer_scope(sym->scope) &&
                     (match_op(token->next,';') || match_op(token->next,'{')))) {
                        // Either a new symbol, or else an out-of-scope
                        // symbol being redefined.
                        sym = alloc_symbol(token->pos, type);
                        bind_symbol(sym, token->ident, NS_STRUCT);
                }
                if (sym->type != type)
                        error_die(token->pos, "invalid tag applied to %s", show_typename (sym));
                ctx->ctype.base_type = sym;
                repos = &token->pos;
                token = token->next;
                if (!match_op(token, '{'))
                        return token;

                // The following test is actually wrong for empty
                // structs, but (1) they are not C99, (2) gcc does
                // the same thing, and (3) it's easier.
                if (sym->symbol_list)
                        error_die(token->pos, "redefinition of %s", show_typename (sym));
                sym->pos = *repos;

                // Mark the structure as needing re-examination
                sym->examined = 0;
        } else if (match_op(token, '{')) {
                // private struct/union/enum type
                sym = alloc_symbol(token->pos, type);
                set_current_scope(sym);         // used by dissect
                ctx->ctype.base_type = sym;
        } else {
                sparse_error(token->pos, "expected declaration");
                ctx->ctype.base_type = &bad_ctype;
                return token;
        }

        token = parse(token->next, sym);
        token = expect(token, '}', "at end of specifier");
        attr.ctype.base_type = sym;
        token = handle_attributes(token, &attr);
        apply_ctype(token->pos, &sym->ctype, &attr.ctype);
        sym->packed = attr.packed;

        sym->endpos = token->pos;

        return token;
}

static struct token *parse_struct_declaration(struct token *token, struct symbol *sym)
{
        struct symbol *field, *last = NULL;
        struct token *res;
        res = struct_declaration_list(token, &sym->symbol_list);
        FOR_EACH_PTR(sym->symbol_list, field) {
                if (!field->ident) {
                        struct symbol *base = field->ctype.base_type;
                        if (base && base->type == SYM_BITFIELD)
                                continue;
                }
                if (last)
                        last->next_subobject = field;
                last = field;
        } END_FOR_EACH_PTR(field);
        return res;
}

static struct token *parse_union_declaration(struct token *token, struct symbol *sym)
{
        return struct_declaration_list(token, &sym->symbol_list);
}

static struct token *struct_specifier(struct token *token, struct symbol *sym, struct decl_state *ctx)
{
        return struct_union_enum_specifier(SYM_STRUCT, token, ctx, parse_struct_declaration);
}

static struct token *union_specifier(struct token *token, struct symbol *sym, struct decl_state *ctx)
{
        return struct_union_enum_specifier(SYM_UNION, token, ctx, parse_union_declaration);
}

///
// safe right shift
//
// This allow to use a shift amount as big (or bigger)
// than the width of the value to be shifted, in which case
// the result is, of course, 0.
static unsigned long long rshift(unsigned long long val, unsigned int n)
{
        if (n >= (sizeof(val) * 8))
                return 0;
        return val >> n;
}

struct range {
        long long               neg;
        unsigned long long      pos;
};

static void update_range(struct range *range, unsigned long long uval, struct symbol *vtype)
{
        long long sval = uval;

        if (is_signed_type(vtype) && (sval < 0)) {
                if (sval < range->neg)
                        range->neg = sval;
        } else {
                if (uval > range->pos)
                        range->pos = uval;
        }
}

static int type_is_ok(struct symbol *type, struct range range)
{
        int shift = type->bit_size;
        int is_unsigned = type->ctype.modifiers & MOD_UNSIGNED;

        if (!is_unsigned)
                shift--;
        if (rshift(range.pos, shift))
                return 0;
        if (range.neg == 0)
                return 1;
        if (is_unsigned)
                return 0;
        if (rshift(~range.neg, shift))
                return 0;
        return 1;
}

static struct range type_range(struct symbol *type)
{
        struct range range;
        unsigned int size = type->bit_size;
        unsigned long long max;
        long long min;

        if (is_signed_type(type)) {
                min = sign_bit(size);
                max = min - 1;
        } else {
                min = 0;
                max = bits_mask(size);
        }

        range.pos = max;
        range.neg = min;
        return range;
}

static int val_in_range(struct range *range, long long sval, struct symbol *vtype)
{
        unsigned long long uval = sval;

        if (is_signed_type(vtype) && (sval < 0))
                return range->neg <= sval;
        else
                return uval <= range->pos;
}

static void cast_enum_list(struct symbol_list *list, struct symbol *base_type)
{
        struct range irange = type_range(&int_ctype);
        struct symbol *sym;

        FOR_EACH_PTR(list, sym) {
                struct expression *expr = sym->initializer;
                struct symbol *ctype;
                long long val;
                if (expr->type != EXPR_VALUE)
                        continue;
                ctype = expr->ctype;
                val = get_expression_value(expr);
                if (is_int_type(ctype) && val_in_range(&irange, val, ctype)) {
                        expr->ctype = &int_ctype;
                        continue;
                }
                cast_value(expr, base_type, expr, ctype);
                expr->ctype = base_type;
        } END_FOR_EACH_PTR(sym);
}

static struct token *parse_enum_declaration(struct token *token, struct symbol *parent)
{
        unsigned long long lastval = 0;
        struct symbol *ctype = NULL, *base_type = NULL;
        struct range range = { };
        int mix_bitwise = 0;

        parent->examined = 1;
        parent->ctype.base_type = &int_ctype;
        while (token_type(token) == TOKEN_IDENT) {
                struct expression *expr = NULL;
                struct token *next = token->next;
                struct decl_state ctx = { };
                struct symbol *sym;

                // FIXME: only 'deprecated' should be accepted
                next = handle_attributes(next, &ctx);

                if (match_op(next, '=')) {
                        next = constant_expression(next->next, &expr);
                        lastval = get_expression_value(expr);
                        ctype = &void_ctype;
                        if (expr && expr->ctype)
                                ctype = expr->ctype;
                } else if (!ctype) {
                        ctype = &int_ctype;
                } else if (is_int_type(ctype)) {
                        lastval++;
                } else {
                        error_die(token->pos, "can't increment the last enum member");
                }

                if (!expr) {
                        expr = alloc_expression(token->pos, EXPR_VALUE);
                        expr->value = lastval;
                        expr->ctype = ctype;
                }

                sym = alloc_symbol(token->pos, SYM_NODE);
                bind_symbol(sym, token->ident, NS_SYMBOL);
                sym->ctype.modifiers &= ~MOD_ADDRESSABLE;
                sym->initializer = expr;
                sym->enum_member = 1;
                sym->ctype.base_type = parent;
                add_ptr_list(&parent->symbol_list, sym);

                if (base_type != &bad_ctype) {
                        if (ctype->type == SYM_NODE)
                                ctype = ctype->ctype.base_type;
                        if (ctype->type == SYM_ENUM) {
                                if (ctype == parent)
                                        ctype = base_type;
                                else 
                                        ctype = ctype->ctype.base_type;
                        }
                        /*
                         * base_type rules:
                         *  - if all enums are of the same type, then
                         *    the base_type is that type (two first
                         *    cases)
                         *  - if enums are of different types, they
                         *    all have to be integer types, and the
                         *    base type is at least "int_ctype".
                         *  - otherwise the base_type is "bad_ctype".
                         */
                        if (!base_type || ctype == &bad_ctype) {
                                base_type = ctype;
                        } else if (ctype == base_type) {
                                /* nothing */
                        } else if (is_int_type(base_type) && is_int_type(ctype)) {
                                base_type = &int_ctype;
                        } else if (is_restricted_type(base_type) != is_restricted_type(ctype)) {
                                if (!mix_bitwise++) {
                                        warning(expr->pos, "mixed bitwiseness");
                                }
                        } else if (is_restricted_type(base_type) && base_type != ctype) {
                                sparse_error(expr->pos, "incompatible restricted type");
                                info(expr->pos, "   expected: %s", show_typename(base_type));
                                info(expr->pos, "        got: %s", show_typename(ctype));
                                base_type = &bad_ctype;
                        } else if (base_type != &bad_ctype) {
                                sparse_error(token->pos, "bad enum definition");
                                base_type = &bad_ctype;
                        }
                        parent->ctype.base_type = base_type;
                }
                if (is_int_type(base_type)) {
                        update_range(&range, lastval, ctype);
                }
                token = next;

                sym->endpos = token->pos;

                if (!match_op(token, ','))
                        break;
                token = token->next;
        }
        if (!base_type) {
                sparse_error(token->pos, "empty enum definition");
                base_type = &bad_ctype;
        }
        else if (!is_int_type(base_type))
                ;
        else if (type_is_ok(&uint_ctype, range))
                base_type = &uint_ctype;
        else if (type_is_ok(&int_ctype, range))
                base_type = &int_ctype;
        else if (type_is_ok(&ulong_ctype, range))
                base_type = &ulong_ctype;
        else if (type_is_ok(&long_ctype, range))
                base_type = &long_ctype;
        else if (type_is_ok(&ullong_ctype, range))
                base_type = &ullong_ctype;
        else if (type_is_ok(&llong_ctype, range))
                base_type = &llong_ctype;
        else
                base_type = &bad_ctype;
        parent->ctype.base_type = base_type;
        parent->ctype.modifiers |= (base_type->ctype.modifiers & MOD_UNSIGNED);
        parent->examined = 0;

        if (mix_bitwise)
                return token;
        cast_enum_list(parent->symbol_list, base_type);

        return token;
}

static struct token *enum_specifier(struct token *token, struct symbol *sym, struct decl_state *ctx)
{
        struct token *ret = struct_union_enum_specifier(SYM_ENUM, token, ctx, parse_enum_declaration);
        struct ctype *ctype = &ctx->ctype.base_type->ctype;

        if (!ctype->base_type)
                ctype->base_type = &incomplete_ctype;

        return ret;
}

static struct token *typeof_specifier(struct token *token, struct symbol *sym, struct decl_state *ctx)
{

        if (!match_op(token, '(')) {
                sparse_error(token->pos, "expected '(' after typeof");
                return token;
        }
        if (lookup_type(token->next)) {
                struct symbol *sym;
                token = typename(token->next, &sym, NULL);
                ctx->ctype.base_type = sym->ctype.base_type;
                apply_ctype(token->pos, &ctx->ctype, &sym->ctype);
        } else {
                struct symbol *typeof_sym = alloc_symbol(token->pos, SYM_TYPEOF);
                token = parse_expression(token->next, &typeof_sym->initializer);

                typeof_sym->endpos = token->pos;
                if (!typeof_sym->initializer) {
                        sparse_error(token->pos, "expected expression after the '(' token");
                        typeof_sym = &bad_ctype;
                }
                ctx->ctype.base_type = typeof_sym;
        }
        return expect(token, ')', "after typeof");
}

static struct token *autotype_specifier(struct token *token, struct symbol *sym, struct decl_state *ctx)
{
        ctx->ctype.base_type = &autotype_ctype;
        ctx->autotype = 1;
        return token;
}

static struct token *ignore_attribute(struct token *token, struct symbol *attr, struct decl_state *ctx)
{
        struct expression *expr = NULL;
        if (match_op(token, '('))
                token = parens_expression(token, &expr, "in attribute");
        return token;
}

static struct token *attribute_packed(struct token *token, struct symbol *attr, struct decl_state *ctx)
{
        if (!ctx->ctype.alignment) {
                ctx->ctype.alignment = 1;
                ctx->packed = 1;
        }
        return token;
}

static struct token *attribute_aligned(struct token *token, struct symbol *attr, struct decl_state *ctx)
{
        int alignment = max_alignment;
        struct expression *expr = NULL;

        if (match_op(token, '(')) {
                token = parens_expression(token, &expr, "in attribute");
                if (expr)
                        alignment = const_expression_value(expr);
        }
        if (alignment & (alignment-1)) {
                warning(token->pos, "I don't like non-power-of-2 alignments");
                return token;
        } else if (alignment > ctx->ctype.alignment)
                ctx->ctype.alignment = alignment;
        return token;
}

static void apply_mod(struct position *pos, unsigned long *mods, unsigned long mod)
{
        if (*mods & mod & ~MOD_DUP_OK)
                warning(*pos, "duplicate %s", modifier_name(mod));
        *mods |= mod;
}

static void apply_qualifier(struct position *pos, struct ctype *ctx, unsigned long qual)
{
        apply_mod(pos, &ctx->modifiers, qual);
}

static struct token *attribute_modifier(struct token *token, struct symbol *attr, struct decl_state *ctx)
{
        apply_mod(&token->pos, &ctx->ctype.modifiers, attr->ctype.modifiers);
        return token;
}

static struct token *attribute_function(struct token *token, struct symbol *attr, struct decl_state *ctx)
{
        apply_mod(&token->pos, &ctx->f_modifiers, attr->ctype.modifiers);
        return token;
}

static struct token *attribute_bitwise(struct token *token, struct symbol *attr, struct decl_state *ctx)
{
        if (Wbitwise)
                attribute_modifier(token, attr, ctx);
        return token;
}

static struct ident *numerical_address_space(int asn)
{
        char buff[32];

        if (!asn)
                return NULL;
        sprintf(buff, "<asn:%d>", asn);
        return built_in_ident(buff);
}

static struct token *attribute_address_space(struct token *token, struct symbol *attr, struct decl_state *ctx)
{
        struct expression *expr = NULL;
        struct ident *as = NULL;
        struct token *next;

        token = expect(token, '(', "after address_space attribute");
        switch (token_type(token)) {
        case TOKEN_NUMBER:
                next = primary_expression(token, &expr);
                if (expr->type != EXPR_VALUE)
                        goto invalid;
                as = numerical_address_space(expr->value);
                break;
        case TOKEN_IDENT:
                next = token->next;
                as = token->ident;
                break;
        default:
                next = token->next;
        invalid:
                as = NULL;
                warning(token->pos, "invalid address space name");
        }

        if (Waddress_space && as) {
                if (ctx->ctype.as)
                        sparse_error(token->pos,
                                     "multiple address spaces given: %s & %s",
                                     show_as(ctx->ctype.as), show_as(as));
                ctx->ctype.as = as;
        }
        token = expect(next, ')', "after address_space attribute");
        return token;
}

static struct symbol *to_QI_mode(struct symbol *ctype)
{
        if (ctype->ctype.base_type != &int_type)
                return NULL;
        if (ctype == &char_ctype)
                return ctype;
        return ctype->ctype.modifiers & MOD_UNSIGNED ? &uchar_ctype
                                                     : &schar_ctype;
}

static struct symbol *to_HI_mode(struct symbol *ctype)
{
        if (ctype->ctype.base_type != &int_type)
                return NULL;
        return ctype->ctype.modifiers & MOD_UNSIGNED ? &ushort_ctype
                                                     : &sshort_ctype;
}

static struct symbol *to_SI_mode(struct symbol *ctype)
{
        if (ctype->ctype.base_type != &int_type)
                return NULL;
        return ctype->ctype.modifiers & MOD_UNSIGNED ? &uint_ctype
                                                     : &sint_ctype;
}

static struct symbol *to_DI_mode(struct symbol *ctype)
{
        if (ctype->ctype.base_type != &int_type)
                return NULL;
        return ctype->ctype.modifiers & MOD_UNSIGNED ? &ullong_ctype
                                                     : &sllong_ctype;
}

static struct symbol *to_TI_mode(struct symbol *ctype)
{
        if (ctype->ctype.base_type != &int_type)
                return NULL;
        return ctype->ctype.modifiers & MOD_UNSIGNED ? &uint128_ctype
                                                     : &sint128_ctype;
}

static struct symbol *to_pointer_mode(struct symbol *ctype)
{
        if (ctype->ctype.base_type != &int_type)
                return NULL;
        return ctype->ctype.modifiers & MOD_UNSIGNED ? uintptr_ctype
                                                     :  intptr_ctype;
}

static struct symbol *to_word_mode(struct symbol *ctype)
{
        if (ctype->ctype.base_type != &int_type)
                return NULL;
        return ctype->ctype.modifiers & MOD_UNSIGNED ? &ulong_ctype
                                                     : &slong_ctype;
}

static struct token *attribute_mode(struct token *token, struct symbol *attr, struct decl_state *ctx)
{
        token = expect(token, '(', "after mode attribute");
        if (token_type(token) == TOKEN_IDENT) {
                struct symbol *mode = lookup_keyword(token->ident, NS_KEYWORD);
                if (mode && mode->op->type & KW_MODE)
                        ctx->mode = mode->op;
                else
                        sparse_error(token->pos, "unknown mode attribute %s", show_ident(token->ident));
                token = token->next;
        } else
                sparse_error(token->pos, "expect attribute mode symbol\n");
        token = expect(token, ')', "after mode attribute");
        return token;
}

static struct token *attribute_context(struct token *token, struct symbol *attr, struct decl_state *ctx)
{
        struct context *context = alloc_context();
        struct expression *args[3];
        int idx = 0;

        token = expect(token, '(', "after context attribute");
        token = conditional_expression(token, &args[0]);
        token = expect(token, ',', "after context 1st argument");
        token = conditional_expression(token, &args[1]);
        if (match_op(token, ',')) {
                token = token->next;
                token = conditional_expression(token, &args[2]);
                token = expect(token, ')', "after context 3rd argument");
                context->context = args[0];
                idx++;
        } else {
                token = expect(token, ')', "after context 2nd argument");
        }
        context->in =  get_expression_value(args[idx++]);
        context->out = get_expression_value(args[idx++]);
        add_ptr_list(&ctx->ctype.contexts, context);
        return token;
}

static struct token *attribute_designated_init(struct token *token, struct symbol *attr, struct decl_state *ctx)
{
        if (ctx->ctype.base_type && ctx->ctype.base_type->type == SYM_STRUCT)
                ctx->ctype.base_type->designated_init = 1;
        else
                warning(token->pos, "attribute designated_init applied to non-structure type");
        return token;
}

static struct token *attribute_transparent_union(struct token *token, struct symbol *attr, struct decl_state *ctx)
{
        if (Wtransparent_union)
                warning(token->pos, "attribute __transparent_union__");

        if (ctx->ctype.base_type && ctx->ctype.base_type->type == SYM_UNION)
                ctx->ctype.base_type->transparent_union = 1;
        else
                warning(token->pos, "attribute __transparent_union__ applied to non-union type");
        return token;
}

static struct token *recover_unknown_attribute(struct token *token)
{
        struct expression *expr = NULL;

        if (Wunknown_attribute)
                warning(token->pos, "unknown attribute '%s'", show_ident(token->ident));
        token = token->next;
        if (match_op(token, '('))
                token = parens_expression(token, &expr, "in attribute");
        return token;
}

static struct token *attribute_specifier(struct token *token, struct symbol *sym, struct decl_state *ctx)
{
        token = expect(token, '(', "after attribute");
        token = expect(token, '(', "after attribute");

        while (token_type(token) == TOKEN_IDENT) {
                struct symbol *attr = lookup_keyword(token->ident, NS_KEYWORD);
                if (attr && attr->op->attribute)
                        token = attr->op->attribute(token->next, attr, ctx);
                else
                        token = recover_unknown_attribute(token);

                if (!match_op(token, ','))
                        break;
                token = token->next;
        }

        token = expect(token, ')', "after attribute");
        token = expect(token, ')', "after attribute");
        return token;
}

static unsigned long decl_modifiers(struct decl_state *ctx)
{
        unsigned long mods = ctx->ctype.modifiers & MOD_DECLARE;
        ctx->ctype.modifiers &= ~MOD_DECLARE;
        return ctx->storage_class | mods;
}

static struct token *storage_specifier(struct token *next, struct symbol *sym, struct decl_state *ctx)
{
        int is_tls = ctx->ctype.modifiers & MOD_TLS;
        unsigned long class = sym->ctype.modifiers;
        const char *storage = modifier_name(class);

        /* __thread can be used alone, or with extern or static */
        if (is_tls && (class & ~(MOD_STATIC|MOD_EXTERN)))
                sparse_error(next->pos, "__thread cannot be used with '%s'", storage);
        else if (!ctx->storage_class)
                ctx->storage_class = class;
        else if (ctx->storage_class == class)
                sparse_error(next->pos, "duplicate %s", storage);
        else
                sparse_error(next->pos, "multiple storage classes");
        return next;
}

static struct token *thread_specifier(struct token *next, struct symbol *sym, struct decl_state *ctx)
{
        /* This GCC extension can be used alone, or with extern or static */
        if (!(ctx->storage_class & ~(MOD_STATIC|MOD_EXTERN))) {
                apply_qualifier(&next->pos, &ctx->ctype, MOD_TLS);
        } else {
                sparse_error(next->pos, "__thread cannot be used with '%s'",
                        modifier_name(ctx->storage_class));
        }

        return next;
}

static struct token *attribute_force(struct token *token, struct symbol *attr, struct decl_state *ctx)
{
        ctx->forced = 1;
        return token;
}

static struct token *alignas_specifier(struct token *token, struct symbol *sym, struct decl_state *ctx)
{
        int alignment = 0;

        if (!match_op(token, '(')) {
                sparse_error(token->pos, "expected '(' after _Alignas");
                return token;
        }
        if (lookup_type(token->next)) {
                struct symbol *sym = NULL;
                token = typename(token->next, &sym, NULL);
                sym = examine_symbol_type(sym);
                alignment = sym->ctype.alignment;
                token = expect(token, ')', "after _Alignas(...");
        } else {
                struct expression *expr = NULL;
                token = parens_expression(token, &expr, "after _Alignas");
                if (!expr)
                        return token;
                alignment = const_expression_value(expr);
        }

        if (alignment < 0) {
                warning(token->pos, "non-positive alignment");
                return token;
        }
        if (alignment & (alignment-1)) {
                warning(token->pos, "non-power-of-2 alignment");
                return token;
        }
        if (alignment > ctx->ctype.alignment)
                ctx->ctype.alignment = alignment;
        return token;
}

static struct token *generic_qualifier(struct token *next, struct symbol *sym, struct decl_state *ctx)
{
        apply_qualifier(&next->pos, &ctx->ctype, sym->ctype.modifiers);
        return next;
}

static void apply_ctype(struct position pos, struct ctype *dst, struct ctype *src)
{
        unsigned long mod = src->modifiers;

        if (mod)
                apply_qualifier(&pos, dst, mod);

        /* Context */
        concat_ptr_list((struct ptr_list *)src->contexts,
                        (struct ptr_list **)&dst->contexts);

        /* Alignment */
        if (src->alignment > dst->alignment)
                dst->alignment = src->alignment;

        /* Address space */
        if (src->as)
                dst->as = src->as;
}

static void specifier_conflict(struct position pos, int what, struct ident *new)
{
        const char *old;
        if (what & (Set_S | Set_T))
                goto Catch_all;
        if (what & Set_Char)
                old = "char";
        else if (what & Set_Double)
                old = "double";
        else if (what & Set_Float)
                old = "float";
        else if (what & Set_Signed)
                old = "signed";
        else if (what & Set_Unsigned)
                old = "unsigned";
        else if (what & Set_Short)
                old = "short";
        else if (what & Set_Long)
                old = "long";
        else
                old = "long long";
        sparse_error(pos, "impossible combination of type specifiers: %s %s",
                        old, show_ident(new));
        return;

Catch_all:
        sparse_error(pos, "two or more data types in declaration specifiers");
}

static struct symbol * const int_types[] =
        {&char_ctype, &short_ctype, &int_ctype, &long_ctype, &llong_ctype, &int128_ctype};
static struct symbol * const signed_types[] =
        {&schar_ctype, &sshort_ctype, &sint_ctype, &slong_ctype, &sllong_ctype,
         &sint128_ctype};
static struct symbol * const unsigned_types[] =
        {&uchar_ctype, &ushort_ctype, &uint_ctype, &ulong_ctype, &ullong_ctype,
         &uint128_ctype};
static struct symbol * const real_types[] =
        {&float_ctype, &double_ctype, &ldouble_ctype};
static struct symbol * const * const types[] = {
        [CInt]  = int_types + 2,
        [CSInt] = signed_types + 2,
        [CUInt] = unsigned_types + 2,
        [CReal] = real_types + 1,
};

struct symbol *ctype_integer(int size, int want_unsigned)
{
        return types[want_unsigned ? CUInt : CInt][size];
}

static struct token *handle_qualifiers(struct token *t, struct decl_state *ctx)
{
        while (token_type(t) == TOKEN_IDENT) {
                struct symbol *s = lookup_keyword(t->ident, NS_TYPEDEF);
                if (!s)
                        break;
                if (!(s->op->type & (KW_ATTRIBUTE | KW_QUALIFIER)))
                        break;
                t = t->next;
                if (s->op->declarator)
                        t = s->op->declarator(t, s, ctx);
        }
        return t;
}

static struct token *declaration_specifiers(struct token *token, struct decl_state *ctx)
{
        int seen = 0;
        int class = CInt;
        int rank = 0;

        while (token_type(token) == TOKEN_IDENT) {
                struct symbol *s = lookup_symbol(token->ident,
                                                 NS_TYPEDEF | NS_SYMBOL);
                if (!s || !(s->namespace & NS_TYPEDEF))
                        break;
                if (s->type != SYM_KEYWORD) {
                        if (seen & Set_Any)
                                break;
                        seen |= Set_S | Set_T;
                        ctx->ctype.base_type = s->ctype.base_type;
                        apply_ctype(token->pos, &ctx->ctype, &s->ctype);
                        token = token->next;
                        continue;
                }
                if (s->op->type & KW_SPECIFIER) {
                        if (seen & s->op->test) {
                                specifier_conflict(token->pos,
                                                   seen & s->op->test,
                                                   token->ident);
                                break;
                        }
                        seen |= s->op->set;
                        class += s->op->class;
                        if (s->op->set & Set_Int128)
                                rank = 3;
                        else if (s->op->set & Set_Char)
                                rank = -2;
                        if (s->op->set & (Set_Short|Set_Float)) {
                                rank = -1;
                        } else if (s->op->set & Set_Long && rank++) {
                                if (class == CReal) {
                                        specifier_conflict(token->pos,
                                                           Set_Vlong,
                                                           &double_ident);
                                        break;
                                }
                                seen |= Set_Vlong;
                        }
                }
                token = token->next;
                if (s->op->declarator)  // Note: this eats attributes
                        token = s->op->declarator(token, s, ctx);
                if (s->op->type & KW_EXACT) {
                        ctx->ctype.base_type = s->ctype.base_type;
                        ctx->ctype.modifiers |= s->ctype.modifiers;
                }
        }

        if (!(seen & Set_S)) {  /* not set explicitly? */
                struct symbol *base = &incomplete_ctype;
                if (seen & Set_Any)
                        base = types[class][rank];
                ctx->ctype.base_type = base;
        }

        if (ctx->ctype.modifiers & MOD_BITWISE) {
                struct symbol *type;
                ctx->ctype.modifiers &= ~MOD_BITWISE;
                if (!is_int_type(ctx->ctype.base_type)) {
                        sparse_error(token->pos, "invalid modifier");
                        return token;
                }
                type = alloc_symbol(token->pos, SYM_BASETYPE);
                *type = *ctx->ctype.base_type;
                type->ctype.modifiers &= ~MOD_SPECIFIER;
                type->ctype.base_type = ctx->ctype.base_type;
                type->type = SYM_RESTRICT;
                ctx->ctype.base_type = type;
                create_fouled(type);
        }
        return token;
}

static struct token *abstract_array_declarator(struct token *token, struct symbol *sym)
{
        struct expression *expr = NULL;
        int has_static = 0;

        while (token_type(token) == TOKEN_IDENT) {
                struct symbol *sym = lookup_keyword(token->ident, NS_TYPEDEF);
                if (!sym || !(sym->op->type & (KW_STATIC|KW_QUALIFIER)))
                        break;
                if (has_static && (sym->op->type & KW_STATIC))
                        sparse_error(token->pos, "duplicate array static declarator");
                has_static |= (sym->op->type & KW_STATIC);
                token = token->next;
        }
        if (match_op(token, '*') && match_op(token->next, ']')) {
                // FIXME: '[*]' is treated like '[]'
                token = token->next;
        } else {
                token = assignment_expression(token, &expr);
        }
        sym->array_size = expr;
        return token;
}

static struct token *parameter_type_list(struct token *, struct symbol *);
static struct token *identifier_list(struct token *, struct symbol *);
static struct token *declarator(struct token *token, struct decl_state *ctx);

static struct token *handle_asm_name(struct token *token, struct decl_state *ctx)
{
        struct expression *expr;
        struct symbol *keyword;

        if (token_type(token) != TOKEN_IDENT)
                return token;
        keyword = lookup_keyword(token->ident, NS_KEYWORD);
        if (!keyword)
                return token;
        if (!(keyword->op->type & KW_ASM))
                return token;

        token = token->next;
        token = expect(token, '(', "after asm");
        token = string_expression(token, &expr, "asm name");
        token = expect(token, ')', "after asm");
        return token;
}

///
// test if @token is '__attribute__' (or one of its variant)
static bool match_attribute(struct token *token)
{
        struct symbol *sym;

        if (token_type(token) != TOKEN_IDENT)
                return false;
        sym = lookup_keyword(token->ident, NS_TYPEDEF);
        if (!sym)
                return false;
        return sym->op->type & KW_ATTRIBUTE;
}

static struct token *skip_attribute(struct token *token)
{
        token = token->next;
        if (match_op(token, '(')) {
                int depth = 1;
                token = token->next;
                while (depth && !eof_token(token)) {
                        if (token_type(token) == TOKEN_SPECIAL) {
                                if (token->special == '(')
                                        depth++;
                                else if (token->special == ')')
                                        depth--;
                        }
                        token = token->next;
                }
        }
        return token;
}

static struct token *skip_attributes(struct token *token)
{
        while (match_attribute(token)) {
                token = expect(token->next, '(', "after attribute");
                token = expect(token, '(', "after attribute");
                while (token_type(token) == TOKEN_IDENT) {
                        token = skip_attribute(token);
                        if (!match_op(token, ','))
                                break;
                        token = token->next;
                }
                token = expect(token, ')', "after attribute");
                token = expect(token, ')', "after attribute");
        }
        return token;
}

static struct token *handle_attributes(struct token *token, struct decl_state *ctx)
{
        while (match_attribute(token))
                token = attribute_specifier(token->next, NULL, ctx);
        return token;
}

static int is_nested(struct token *token, struct token **p,
                    int prefer_abstract)
{
        /*
         * This can be either a parameter list or a grouping.
         * For the direct (non-abstract) case, we know if must be
         * a parameter list if we already saw the identifier.
         * For the abstract case, we know if must be a parameter
         * list if it is empty or starts with a type.
         */
        struct token *next = token->next;

        *p = next = skip_attributes(next);

        if (token_type(next) == TOKEN_IDENT) {
                if (lookup_type(next))
                        return !prefer_abstract;
                return 1;
        }

        if (match_op(next, ')') || match_op(next, SPECIAL_ELLIPSIS))
                return 0;

        return 1;
}

enum kind {
        Empty, K_R, Proto, Bad_Func,
};

static enum kind which_func(struct token *token,
                            struct ident **n,
                            int prefer_abstract)
{
        struct token *next = token->next;

        if (token_type(next) == TOKEN_IDENT) {
                if (lookup_type(next))
                        return Proto;
                /* identifier list not in definition; complain */
                if (prefer_abstract)
                        warning(token->pos,
                                "identifier list not in definition");
                return K_R;
        }

        if (token_type(next) != TOKEN_SPECIAL)
                return Bad_Func;

        if (next->special == ')') {
                /* don't complain about those */
                if (!n || match_op(next->next, ';') || match_op(next->next, ','))
                        return Empty;
                if (Wstrict_prototypes)
                        warning(next->pos,
                                "non-ANSI function declaration of function '%s'",
                                show_ident(*n));
                return Empty;
        }

        if (next->special == SPECIAL_ELLIPSIS) {
                warning(next->pos,
                        "variadic functions must have one named argument");
                return Proto;
        }

        return Bad_Func;
}

static struct token *direct_declarator(struct token *token, struct decl_state *ctx)
{
        struct ctype *ctype = &ctx->ctype;
        struct token *next;
        struct ident **p = ctx->ident;

        if (ctx->ident && token_type(token) == TOKEN_IDENT) {
                *ctx->ident = token->ident;
                token = token->next;
        } else if (match_op(token, '(') &&
            is_nested(token, &next, ctx->prefer_abstract)) {
                struct symbol *base_type = ctype->base_type;
                if (token->next != next)
                        next = handle_attributes(token->next, ctx);
                token = declarator(next, ctx);
                token = expect(token, ')', "in nested declarator");
                while (ctype->base_type != base_type)
                        ctype = &ctype->base_type->ctype;
                p = NULL;
        }

        if (match_op(token, '(')) {
                enum kind kind = which_func(token, p, ctx->prefer_abstract);
                struct symbol *fn;
                fn = alloc_indirect_symbol(token->pos, ctype, SYM_FN);
                ctype->modifiers |= ctx->f_modifiers;
                token = token->next;
                if (kind == K_R)
                        token = identifier_list(token, fn);
                else if (kind == Proto)
                        token = parameter_type_list(token, fn);
                token = expect(token, ')', "in function declarator");
                fn->endpos = token->pos;
                return token;
        }

        while (match_op(token, '[')) {
                struct symbol *array;
                array = alloc_indirect_symbol(token->pos, ctype, SYM_ARRAY);
                token = abstract_array_declarator(token->next, array);
                token = expect(token, ']', "in abstract_array_declarator");
                array->endpos = token->pos;
                ctype = &array->ctype;
        }
        return token;
}

static struct token *pointer(struct token *token, struct decl_state *ctx)
{
        while (match_op(token,'*')) {
                struct symbol *ptr = alloc_symbol(token->pos, SYM_PTR);
                ptr->ctype.modifiers = ctx->ctype.modifiers;
                ptr->ctype.base_type = ctx->ctype.base_type;
                ptr->ctype.as = ctx->ctype.as;
                ptr->ctype.contexts = ctx->ctype.contexts;
                ctx->ctype.modifiers = 0;
                ctx->ctype.base_type = ptr;
                ctx->ctype.as = NULL;
                ctx->ctype.contexts = NULL;
                ctx->ctype.alignment = 0;

                token = handle_qualifiers(token->next, ctx);
                ctx->ctype.base_type->endpos = token->pos;
        }
        return token;
}

static struct token *declarator(struct token *token, struct decl_state *ctx)
{
        token = pointer(token, ctx);
        return direct_declarator(token, ctx);
}

static struct token *handle_bitfield(struct token *token, struct decl_state *ctx)
{
        struct ctype *ctype = &ctx->ctype;
        struct expression *expr;
        struct symbol *bitfield;
        long long width;

        if (ctype->base_type != &int_type && !is_int_type(ctype->base_type)) {
                sparse_error(token->pos, "invalid bitfield specifier for type %s.",
                        show_typename(ctype->base_type));
                // Parse this to recover gracefully.
                return conditional_expression(token->next, &expr);
        }

        bitfield = alloc_indirect_symbol(token->pos, ctype, SYM_BITFIELD);
        token = conditional_expression(token->next, &expr);
        width = const_expression_value(expr);
        bitfield->bit_size = width;

        if (width < 0 || width > INT_MAX || (*ctx->ident && width == 0)) {
                sparse_error(token->pos, "bitfield '%s' has invalid width (%lld)",
                        show_ident(*ctx->ident), width);
                width = -1;
        } else if (*ctx->ident) {
                struct symbol *base_type = bitfield->ctype.base_type;
                struct symbol *bitfield_type = base_type == &int_type ? bitfield : base_type;
                int is_signed = !(bitfield_type->ctype.modifiers & MOD_UNSIGNED);
                if (Wone_bit_signed_bitfield && width == 1 && is_signed) {
                        // Valid values are either {-1;0} or {0}, depending on integer
                        // representation.  The latter makes for very efficient code...
                        sparse_error(token->pos, "dubious one-bit signed bitfield");
                }
                if (Wdefault_bitfield_sign &&
                    bitfield_type->type != SYM_ENUM &&
                    !(bitfield_type->ctype.modifiers & MOD_EXPLICITLY_SIGNED) &&
                    is_signed) {
                        // The sign of bitfields is unspecified by default.
                        warning(token->pos, "dubious bitfield without explicit `signed' or `unsigned'");
                }
        }
        bitfield->bit_size = width;
        bitfield->endpos = token->pos;
        bitfield->ident = *ctx->ident;
        return token;
}

static struct token *declaration_list(struct token *token, struct symbol_list **list)
{
        struct decl_state ctx = {.prefer_abstract = 0};
        struct ctype saved;
        unsigned long mod;

        token = declaration_specifiers(token, &ctx);
        mod = decl_modifiers(&ctx);
        saved = ctx.ctype;
        for (;;) {
                struct symbol *decl = alloc_symbol(token->pos, SYM_NODE);
                ctx.ident = &decl->ident;

                token = declarator(token, &ctx);
                if (match_op(token, ':'))
                        token = handle_bitfield(token, &ctx);

                token = handle_attributes(token, &ctx);
                apply_modifiers(token->pos, &ctx);

                decl->ctype = ctx.ctype;
                decl->ctype.modifiers |= mod;
                decl->endpos = token->pos;
                add_symbol(list, decl);
                if (!match_op(token, ','))
                        break;
                token = token->next;
                ctx.ctype = saved;
        }
        return token;
}

static struct token *struct_declaration_list(struct token *token, struct symbol_list **list)
{
        while (!match_op(token, '}')) {
                if (match_ident(token, &_Static_assert_ident)) {
                        token = parse_static_assert(token, NULL);
                        continue;
                }
                if (!match_op(token, ';'))
                        token = declaration_list(token, list);
                if (!match_op(token, ';')) {
                        sparse_error(token->pos, "expected ; at end of declaration");
                        break;
                }
                token = token->next;
        }
        return token;
}

static struct token *parameter_declaration(struct token *token, struct symbol *sym)
{
        struct decl_state ctx = {.prefer_abstract = 1};

        token = declaration_specifiers(token, &ctx);
        ctx.ident = &sym->ident;
        token = declarator(token, &ctx);
        token = handle_attributes(token, &ctx);
        apply_modifiers(token->pos, &ctx);
        sym->ctype = ctx.ctype;
        sym->ctype.modifiers |= decl_modifiers(&ctx);
        sym->endpos = token->pos;
        sym->forced_arg = ctx.forced;
        return token;
}

struct token *typename(struct token *token, struct symbol **p, int *forced)
{
        struct decl_state ctx = {.prefer_abstract = 1};
        unsigned long class;
        struct symbol *sym = alloc_symbol(token->pos, SYM_NODE);
        *p = sym;
        token = declaration_specifiers(token, &ctx);
        token = declarator(token, &ctx);
        apply_modifiers(token->pos, &ctx);
        sym->ctype = ctx.ctype;
        sym->endpos = token->pos;
        class = ctx.storage_class;
        if (forced)
                *forced = ctx.forced;
        if (class)
                warning(sym->pos, "storage class in typename (%s%s)",
                        modifier_string(class), show_typename(sym));
        return token;
}

static struct token *parse_underscore_Pragma(struct token *token)
{
        struct token *next;

        next = token->next;
        if (!match_op(next, '('))
                return next;
        next = next->next;
        if (next->pos.type != TOKEN_STRING)
                return next;
        next = next->next;
        if (!match_op(next, ')'))
                return next;
        return next->next;
}

static struct token *expression_statement(struct token *token, struct expression **tree)
{
        if (match_ident(token, &_Pragma_ident))
                return parse_underscore_Pragma(token);

        token = parse_expression(token, tree);
        return expect(token, ';', "at end of statement");
}

static struct token *parse_asm_operands(struct token *token, struct statement *stmt,
        struct asm_operand_list **inout)
{
        /* Allow empty operands */
        if (match_op(token->next, ':') || match_op(token->next, ')'))
                return token->next;
        do {
                struct asm_operand *op = __alloc_asm_operand(0);
                if (match_op(token->next, '[') &&
                    token_type(token->next->next) == TOKEN_IDENT &&
                    match_op(token->next->next->next, ']')) {
                        op->name = token->next->next->ident;
                        token = token->next->next->next;
                }
                token = token->next;
                token = string_expression(token, &op->constraint, "asm constraint");
                token = parens_expression(token, &op->expr, "in asm parameter");
                add_ptr_list(inout, op);
        } while (match_op(token, ','));
        return token;
}

static struct token *parse_asm_clobbers(struct token *token, struct statement *stmt,
        struct expression_list **clobbers)
{
        struct expression *expr;

        do {
                token = primary_expression(token->next, &expr);
                if (expr)
                        add_expression(clobbers, expr);
        } while (match_op(token, ','));
        return token;
}

static struct token *parse_asm_labels(struct token *token, struct statement *stmt,
                        struct symbol_list **labels)
{
        struct symbol *label;

        do {
                token = token->next; /* skip ':' and ',' */
                if (token_type(token) != TOKEN_IDENT)
                        return token;
                label = label_symbol(token, 1);
                add_symbol(labels, label);
                token = token->next;
        } while (match_op(token, ','));
        return token;
}

static struct token *parse_asm_statement(struct token *token, struct statement *stmt)
{
        unsigned long mods = 0;

        token = token->next;
        stmt->type = STMT_ASM;
        while (token_type(token) == TOKEN_IDENT) {
                struct symbol *s = lookup_keyword(token->ident, NS_TYPEDEF);
                if (s && s->op->asm_modifier)
                        s->op->asm_modifier(token, &mods, s->ctype.modifiers);
                else if (token->ident == &goto_ident)
                        asm_modifier(token, &mods, MOD_ASM_GOTO);
                token = token->next;
        }
        token = expect(token, '(', "after asm");
        token = string_expression(token, &stmt->asm_string, "inline asm");
        if (match_op(token, ':'))
                token = parse_asm_operands(token, stmt, &stmt->asm_outputs);
        if (match_op(token, ':'))
                token = parse_asm_operands(token, stmt, &stmt->asm_inputs);
        if (match_op(token, ':'))
                token = parse_asm_clobbers(token, stmt, &stmt->asm_clobbers);
        if (match_op(token, ':') && (mods & MOD_ASM_GOTO))
                token = parse_asm_labels(token, stmt, &stmt->asm_labels);
        token = expect(token, ')', "after asm");
        return expect(token, ';', "at end of asm-statement");
}

static struct token *parse_static_assert(struct token *token, struct symbol_list **unused)
{
        struct expression *cond = NULL, *message = NULL;

        token = expect(token->next, '(', "after _Static_assert");
        token = constant_expression(token, &cond);
        if (!cond)
                sparse_error(token->pos, "Expected constant expression");
        if (match_op(token, ',')) {
                token = token->next;
                token = string_expression(token, &message, "_Static_assert()");
                if (!message)
                        cond = NULL;
        }
        token = expect(token, ')', "after diagnostic message in _Static_assert");
        token = expect(token, ';', "after _Static_assert()");

        if (cond && !const_expression_value(cond) && cond->type == EXPR_VALUE) {
                const char *sep = "", *msg = "";

                if (message) {
                        sep = ": ";
                        msg = show_string(message->string);
                }
                sparse_error(cond->pos, "static assertion failed%s%s", sep, msg);
        }

        return token;
}

/* Make a statement out of an expression */
static struct statement *make_statement(struct expression *expr)
{
        struct statement *stmt;

        if (!expr)
                return NULL;
        stmt = alloc_statement(expr->pos, STMT_EXPRESSION);
        stmt->expression = expr;
        return stmt;
}

/*
 * All iterators have two symbols associated with them:
 * the "continue" and "break" symbols, which are targets
 * for continue and break statements respectively.
 *
 * They are in a special name-space, but they follow
 * all the normal visibility rules, so nested iterators
 * automatically work right.
 */
static void start_iterator(struct statement *stmt)
{
        struct symbol *cont, *brk;

        start_block_scope(stmt->pos);
        cont = alloc_symbol(stmt->pos, SYM_NODE);
        bind_symbol(cont, &continue_ident, NS_ITERATOR);
        brk = alloc_symbol(stmt->pos, SYM_NODE);
        bind_symbol(brk, &break_ident, NS_ITERATOR);

        stmt->type = STMT_ITERATOR;
        stmt->iterator_break = brk;
        stmt->iterator_continue = cont;
        fn_local_symbol(brk);
        fn_local_symbol(cont);
}

static void end_iterator(struct statement *stmt)
{
        end_block_scope();
}

static struct statement *start_function(struct symbol *sym)
{
        struct symbol *ret;
        struct statement *stmt = alloc_statement(sym->pos, STMT_COMPOUND);

        start_function_scope(sym->pos);
        ret = alloc_symbol(sym->pos, SYM_NODE);
        ret->ctype = sym->ctype.base_type->ctype;
        ret->ctype.modifiers &= ~(MOD_STORAGE | MOD_QUALIFIER | MOD_TLS | MOD_ACCESS | MOD_NOCAST | MOD_NODEREF);
        ret->ctype.modifiers |= (MOD_AUTO | MOD_REGISTER);
        bind_symbol(ret, &return_ident, NS_ITERATOR);
        stmt->ret = ret;
        fn_local_symbol(ret);

        // Currently parsed symbol for __func__/__FUNCTION__/__PRETTY_FUNCTION__
        current_fn = sym;

        return stmt;
}

static void end_function(struct symbol *sym)
{
        current_fn = NULL;
        end_function_scope();
}

/*
 * A "switch()" statement, like an iterator, has a
 * the "break" symbol associated with it. It works
 * exactly like the iterator break - it's the target
 * for any break-statements in scope, and means that
 * "break" handling doesn't even need to know whether
 * it's breaking out of an iterator or a switch.
 *
 * In addition, the "case" symbol is a marker for the
 * case/default statements to find the switch statement
 * that they are associated with.
 */
static void start_switch(struct statement *stmt)
{
        struct symbol *brk, *switch_case;

        start_block_scope(stmt->pos);
        brk = alloc_symbol(stmt->pos, SYM_NODE);
        bind_symbol(brk, &break_ident, NS_ITERATOR);

        switch_case = alloc_symbol(stmt->pos, SYM_NODE);
        bind_symbol(switch_case, &case_ident, NS_ITERATOR);
        switch_case->stmt = stmt;

        stmt->type = STMT_SWITCH;
        stmt->switch_break = brk;
        stmt->switch_case = switch_case;

        fn_local_symbol(brk);
        fn_local_symbol(switch_case);
}

static void end_switch(struct statement *stmt)
{
        if (!stmt->switch_case->symbol_list)
                warning(stmt->pos, "switch with no cases");
        end_block_scope();
}

static void add_case_statement(struct statement *stmt)
{
        struct symbol *target = lookup_symbol(&case_ident, NS_ITERATOR);
        struct symbol *sym;

        if (!target) {
                sparse_error(stmt->pos, "not in switch scope");
                stmt->type = STMT_NONE;
                return;
        }
        sym = alloc_symbol(stmt->pos, SYM_NODE);
        add_symbol(&target->symbol_list, sym);
        sym->stmt = stmt;
        stmt->case_label = sym;
        fn_local_symbol(sym);
}

static struct token *parse_return_statement(struct token *token, struct statement *stmt)
{
        struct symbol *target = lookup_symbol(&return_ident, NS_ITERATOR);

        if (!target)
                error_die(token->pos, "internal error: return without a function target");
        stmt->type = STMT_RETURN;
        stmt->ret_target = target;
        return expression_statement(token->next, &stmt->ret_value);
}

static void validate_for_loop_decl(struct symbol *sym)
{
        unsigned long storage = sym->ctype.modifiers & MOD_STORAGE;

        if (storage & ~(MOD_AUTO | MOD_REGISTER)) {
                const char *name = show_ident(sym->ident);
                sparse_error(sym->pos, "non-local var '%s' in for-loop initializer", name);
                sym->ctype.modifiers &= ~MOD_STORAGE;
        }
}

static struct token *parse_for_statement(struct token *token, struct statement *stmt)
{
        struct symbol_list *syms;
        struct expression *e1, *e2, *e3;
        struct statement *iterator;

        start_iterator(stmt);
        token = expect(token->next, '(', "after 'for'");

        syms = NULL;
        e1 = NULL;
        /* C99 variable declaration? */
        if (lookup_type(token)) {
                token = external_declaration(token, &syms, validate_for_loop_decl);
        } else {
                token = parse_expression(token, &e1);
                token = expect(token, ';', "in 'for'");
        }
        token = parse_expression(token, &e2);
        token = expect(token, ';', "in 'for'");
        token = parse_expression(token, &e3);
        token = expect(token, ')', "in 'for'");
        token = statement(token, &iterator);

        stmt->iterator_syms = syms;
        stmt->iterator_pre_statement = make_statement(e1);
        stmt->iterator_pre_condition = e2;
        stmt->iterator_post_statement = make_statement(e3);
        stmt->iterator_post_condition = NULL;
        stmt->iterator_statement = iterator;
        end_iterator(stmt);

        return token;
}

static struct token *parse_while_statement(struct token *token, struct statement *stmt)
{
        struct expression *expr;
        struct statement *iterator;

        start_iterator(stmt);
        token = parens_expression(token->next, &expr, "after 'while'");
        token = statement(token, &iterator);

        stmt->iterator_pre_condition = expr;
        stmt->iterator_post_condition = NULL;
        stmt->iterator_statement = iterator;
        end_iterator(stmt);

        return token;
}

static struct token *parse_do_statement(struct token *token, struct statement *stmt)
{
        struct expression *expr;
        struct statement *iterator;

        start_iterator(stmt);
        token = statement(token->next, &iterator);
        if (token_type(token) == TOKEN_IDENT && token->ident == &while_ident)
                token = token->next;
        else
                sparse_error(token->pos, "expected 'while' after 'do'");
        token = parens_expression(token, &expr, "after 'do-while'");

        stmt->iterator_post_condition = expr;
        stmt->iterator_statement = iterator;
        end_iterator(stmt);

        if (iterator && iterator->type != STMT_COMPOUND && Wdo_while)
                warning(iterator->pos, "do-while statement is not a compound statement");

        return expect(token, ';', "after statement");
}

static struct token *parse_if_statement(struct token *token, struct statement *stmt)
{
        stmt->type = STMT_IF;
        token = parens_expression(token->next, &stmt->if_conditional, "after if");
        token = statement(token, &stmt->if_true);
        if (token_type(token) != TOKEN_IDENT)
                return token;
        if (token->ident != &else_ident)
                return token;
        return statement(token->next, &stmt->if_false);
}

static inline struct token *case_statement(struct token *token, struct statement *stmt)
{
        stmt->type = STMT_CASE;
        token = expect(token, ':', "after default/case");
        add_case_statement(stmt);
        return statement(token, &stmt->case_statement);
}

static struct token *parse_case_statement(struct token *token, struct statement *stmt)
{
        token = parse_expression(token->next, &stmt->case_expression);
        if (match_op(token, SPECIAL_ELLIPSIS))
                token = parse_expression(token->next, &stmt->case_to);
        return case_statement(token, stmt);
}

static struct token *parse_default_statement(struct token *token, struct statement *stmt)
{
        return case_statement(token->next, stmt);
}

static struct token *parse_loop_iterator(struct token *token, struct statement *stmt)
{
        struct symbol *target = lookup_symbol(token->ident, NS_ITERATOR);
        stmt->type = STMT_GOTO;
        stmt->goto_label = target;
        if (!target)
                sparse_error(stmt->pos, "break/continue not in iterator scope");
        return expect(token->next, ';', "at end of statement");
}

static struct token *parse_switch_statement(struct token *token, struct statement *stmt)
{
        stmt->type = STMT_SWITCH;
        start_switch(stmt);
        token = parens_expression(token->next, &stmt->switch_expression, "after 'switch'");
        token = statement(token, &stmt->switch_statement);
        end_switch(stmt);
        return token;
}

static void warn_label_usage(struct position def, struct position use, struct ident *ident)
{
        const char *id = show_ident(ident);
        sparse_error(use, "label '%s' used outside statement expression", id);
        info(def, "   label '%s' defined here", id);
        current_fn->bogus_linear = 1;
}

void check_label_usage(struct symbol *label, struct position use_pos)
{
        struct statement *def = label->stmt;

        if (def) {
                if (!is_in_scope(def->label_scope, label_scope))
                        warn_label_usage(def->pos, use_pos, label->ident);
        } else if (!label->label_scope) {
                label->label_scope = label_scope;
                label->label_pos = use_pos;
        }
}

static struct token *parse_goto_statement(struct token *token, struct statement *stmt)
{
        stmt->type = STMT_GOTO;
        token = token->next;
        if (match_op(token, '*')) {
                token = parse_expression(token->next, &stmt->goto_expression);
                add_statement(&function_computed_goto_list, stmt);
        } else if (token_type(token) == TOKEN_IDENT) {
                struct symbol *label = label_symbol(token, 1);
                stmt->goto_label = label;
                check_label_usage(label, stmt->pos);
                token = token->next;
        } else {
                sparse_error(token->pos, "Expected identifier or goto expression");
        }
        return expect(token, ';', "at end of statement");
}

static struct token *parse_context_statement(struct token *token, struct statement *stmt)
{
        stmt->type = STMT_CONTEXT;
        token = token->next;
        token = expect(token, '(', "after __context__ statement");
        token = assignment_expression(token, &stmt->expression);
        if (!stmt->expression)
                unexpected(token, "expression expected after '('");
        if (match_op(token, ',')) {
                token = token->next;
                stmt->context = stmt->expression;
                token = assignment_expression(token, &stmt->expression);
                if (!stmt->expression)
                        unexpected(token, "expression expected after ','");
        }
        token = expect(token, ')', "at end of __context__ statement");
        return expect(token, ';', "at end of statement");
}

static struct token *parse_range_statement(struct token *token, struct statement *stmt)
{
        stmt->type = STMT_RANGE;
        token = token->next;
        token = expect(token, '(', "after __range__ statement");
        token = assignment_expression(token, &stmt->range_expression);
        token = expect(token, ',', "after range expression");
        token = assignment_expression(token, &stmt->range_low);
        token = expect(token, ',', "after low range");
        token = assignment_expression(token, &stmt->range_high);
        token = expect(token, ')', "after range statement");
        return expect(token, ';', "after range statement");
}

static struct token *handle_label_attributes(struct token *token, struct symbol *label)
{
        struct decl_state ctx = { };

        token = handle_attributes(token, &ctx);
        label->label_modifiers = ctx.ctype.modifiers;
        return token;
}

static struct token *statement(struct token *token, struct statement **tree)
{
        struct statement *stmt = alloc_statement(token->pos, STMT_NONE);

        *tree = stmt;
        if (token_type(token) == TOKEN_IDENT) {
                struct symbol *s = lookup_keyword(token->ident, NS_KEYWORD);
                if (s && s->op->statement)
                        return s->op->statement(token, stmt);

                if (match_op(token->next, ':')) {
                        struct symbol *s = label_symbol(token, 0);
                        token = handle_label_attributes(token->next->next, s);
                        if (s->stmt) {
                                sparse_error(stmt->pos, "label '%s' redefined", show_ident(s->ident));
                                // skip the label to avoid multiple definitions
                                return statement(token, tree);
                        }
                        stmt->type = STMT_LABEL;
                        stmt->label_identifier = s;
                        stmt->label_scope = label_scope;
                        if (s->label_scope) {
                                if (!is_in_scope(label_scope, s->label_scope))
                                        warn_label_usage(stmt->pos, s->label_pos, s->ident);
                        }
                        s->stmt = stmt;
                        if (match_op(token, '}')) {
                                warning(token->pos, "statement expected after label");
                                stmt->label_statement = alloc_statement(token->pos, STMT_NONE);
                                return token;
                        }
                        return statement(token, &stmt->label_statement);
                }
        }

        if (match_op(token, '{')) {
                token = compound_statement(token->next, stmt);
                return expect(token, '}', "at end of compound statement");
        }
                        
        stmt->type = STMT_EXPRESSION;
        return expression_statement(token, &stmt->expression);
}

/* gcc extension - __label__ ident-list; in the beginning of compound stmt */
static struct token *label_statement(struct token *token)
{
        while (token_type(token) == TOKEN_IDENT) {
                struct symbol *sym = alloc_symbol(token->pos, SYM_LABEL);
                /* it's block-scope, but we want label namespace */
                bind_symbol_with_scope(sym, token->ident, NS_LABEL, block_scope);
                fn_local_symbol(sym);
                token = token->next;
                if (!match_op(token, ','))
                        break;
                token = token->next;
        }
        return expect(token, ';', "at end of label declaration");
}

static struct token * statement_list(struct token *token, struct statement_list **list)
{
        int seen_statement = 0;
        while (token_type(token) == TOKEN_IDENT &&
               token->ident == &__label___ident)
                token = label_statement(token->next);
        for (;;) {
                struct statement * stmt;
                if (eof_token(token))
                        break;
                if (match_op(token, '}'))
                        break;
                if (match_ident(token, &_Static_assert_ident)) {
                        token = parse_static_assert(token, NULL);
                        continue;
                }
                if (lookup_type(token)) {
                        if (seen_statement) {
                                warning(token->pos, "mixing declarations and code");
                                seen_statement = 0;
                        }
                        stmt = alloc_statement(token->pos, STMT_DECLARATION);
                        token = external_declaration(token, &stmt->declaration, NULL);
                } else {
                        seen_statement = Wdeclarationafterstatement;
                        token = statement(token, &stmt);
                }
                add_statement(list, stmt);
        }
        return token;
}

static struct token *identifier_list(struct token *token, struct symbol *fn)
{
        struct symbol_list **list = &fn->arguments;
        for (;;) {
                struct symbol *sym = alloc_symbol(token->pos, SYM_NODE);
                sym->ident = token->ident;
                token = token->next;
                sym->endpos = token->pos;
                sym->ctype.base_type = &incomplete_ctype;
                add_symbol(list, sym);
                if (!match_op(token, ',') ||
                    token_type(token->next) != TOKEN_IDENT ||
                    lookup_type(token->next))
                        break;
                token = token->next;
        }
        return token;
}

static struct token *parameter_type_list(struct token *token, struct symbol *fn)
{
        struct symbol_list **list = &fn->arguments;

        for (;;) {
                struct symbol *sym;

                if (match_op(token, SPECIAL_ELLIPSIS)) {
                        fn->variadic = 1;
                        token = token->next;
                        break;
                }

                sym = alloc_symbol(token->pos, SYM_NODE);
                token = parameter_declaration(token, sym);
                if (sym->ctype.base_type == &void_ctype) {
                        /* Special case: (void) */
                        if (!*list && !sym->ident)
                                break;
                        warning(token->pos, "void parameter");
                }
                add_symbol(list, sym);
                if (!match_op(token, ','))
                        break;
                token = token->next;
        }
        return token;
}

struct token *compound_statement(struct token *token, struct statement *stmt)
{
        stmt->type = STMT_COMPOUND;
        start_block_scope(token->pos);
        token = statement_list(token, &stmt->stmts);
        end_block_scope();
        return token;
}

static struct expression *identifier_expression(struct token *token)
{
        struct expression *expr = alloc_expression(token->pos, EXPR_IDENTIFIER);
        expr->expr_ident = token->ident;
        return expr;
}

static struct expression *index_expression(struct expression *from, struct expression *to)
{
        int idx_from, idx_to;
        struct expression *expr = alloc_expression(from->pos, EXPR_INDEX);

        idx_from = const_expression_value(from);
        idx_to = idx_from;
        if (to) {
                idx_to = const_expression_value(to);
                if (idx_to < idx_from || idx_from < 0)
                        warning(from->pos, "nonsense array initializer index range");
        }
        expr->idx_from = idx_from;
        expr->idx_to = idx_to;
        return expr;
}

static struct token *single_initializer(struct expression **ep, struct token *token)
{
        int expect_equal = 0;
        struct token *next = token->next;
        struct expression **tail = ep;
        int nested;

        *ep = NULL; 

        if ((token_type(token) == TOKEN_IDENT) && match_op(next, ':')) {
                struct expression *expr = identifier_expression(token);
                if (Wold_initializer)
                        warning(token->pos, "obsolete struct initializer, use C99 syntax");
                token = initializer(&expr->ident_expression, next->next);
                if (expr->ident_expression)
                        *ep = expr;
                return token;
        }

        for (tail = ep, nested = 0; ; nested++, next = token->next) {
                if (match_op(token, '.') && (token_type(next) == TOKEN_IDENT)) {
                        struct expression *expr = identifier_expression(next);
                        *tail = expr;
                        tail = &expr->ident_expression;
                        expect_equal = 1;
                        token = next->next;
                } else if (match_op(token, '[')) {
                        struct expression *from = NULL, *to = NULL, *expr;
                        token = constant_expression(token->next, &from);
                        if (!from) {
                                sparse_error(token->pos, "Expected constant expression");
                                break;
                        }
                        if (match_op(token, SPECIAL_ELLIPSIS))
                                token = constant_expression(token->next, &to);
                        expr = index_expression(from, to);
                        *tail = expr;
                        tail = &expr->idx_expression;
                        token = expect(token, ']', "at end of initializer index");
                        if (nested)
                                expect_equal = 1;
                } else {
                        break;
                }
        }
        if (nested && !expect_equal) {
                if (!match_op(token, '='))
                        warning(token->pos, "obsolete array initializer, use C99 syntax");
                else
                        expect_equal = 1;
        }
        if (expect_equal)
                token = expect(token, '=', "at end of initializer index");

        token = initializer(tail, token);
        if (!*tail)
                *ep = NULL;
        return token;
}

static struct token *initializer_list(struct expression_list **list, struct token *token)
{
        struct expression *expr;

        for (;;) {
                token = single_initializer(&expr, token);
                if (!expr)
                        break;
                add_expression(list, expr);
                if (!match_op(token, ','))
                        break;
                token = token->next;
        }
        return token;
}

struct token *initializer(struct expression **tree, struct token *token)
{
        if (match_op(token, '{')) {
                struct expression *expr = alloc_expression(token->pos, EXPR_INITIALIZER);
                *tree = expr;
                if (!Wuniversal_initializer) {
                        struct token *next = token->next;
                        // '{ 0 }' is equivalent to '{ }' except for some
                        // warnings, like using 0 to initialize a null-pointer.
                        if (match_token_zero(next)) {
                                if (match_op(next->next, '}'))
                                        expr->zero_init = 1;
                        }
                }

                token = initializer_list(&expr->expr_list, token->next);
                return expect(token, '}', "at end of initializer");
        }
        return assignment_expression(token, tree);
}

static void declare_argument(struct symbol *sym, struct symbol *fn)
{
        if (!sym->ident) {
                sparse_error(sym->pos, "no identifier for function argument");
                return;
        }
        if (sym->ctype.base_type == &incomplete_ctype) {
                sym->ctype.base_type = &int_ctype;

                if (Wimplicit_int) {
                        sparse_error(sym->pos, "missing type declaration for parameter '%s'",
                                show_ident(sym->ident));
                }
        }
        bind_symbol(sym, sym->ident, NS_SYMBOL);
}

static int is_syscall(struct symbol *sym)
{
        char *macro;
        char *name;
        int is_syscall = 0;

        macro = get_macro_name(sym->pos);
        if (macro &&
            (strncmp("SYSCALL_DEFINE", macro, strlen("SYSCALL_DEFINE")) == 0 ||
             strncmp("COMPAT_SYSCALL_DEFINE", macro, strlen("COMPAT_SYSCALL_DEFINE")) == 0))
                is_syscall = 1;

        name = sym->ident->name;

        if (name && strncmp(name, "sys_", 4) ==0)
                is_syscall = 1;
        
        if (name && strncmp(name, "compat_sys_", 11) == 0)
                is_syscall = 1;

        return is_syscall;
}
    

static struct token *parse_function_body(struct token *token, struct symbol *decl,
        struct symbol_list **list)
{
        struct symbol_list **old_symbol_list;
        struct symbol *base_type = decl->ctype.base_type;
        struct statement *stmt, **p;
        struct symbol *prev;
        struct symbol *arg;

        old_symbol_list = function_symbol_list;
        if (decl->ctype.modifiers & MOD_INLINE) {
                function_symbol_list = &decl->inline_symbol_list;
                p = &base_type->inline_stmt;
        } else {
                function_symbol_list = &decl->symbol_list;
                p = &base_type->stmt;
        }
        function_computed_target_list = NULL;
        function_computed_goto_list = NULL;

        if ((decl->ctype.modifiers & (MOD_EXTERN|MOD_INLINE)) == MOD_EXTERN) {
                if (Wexternal_function_has_definition)
                        warning(decl->pos, "function '%s' with external linkage has definition", show_ident(decl->ident));
        }
        if (!(decl->ctype.modifiers & MOD_STATIC))
                decl->ctype.modifiers |= MOD_EXTERN;

        stmt = start_function(decl);
        *p = stmt;

        FOR_EACH_PTR (base_type->arguments, arg) {
                declare_argument(arg, base_type);
        } END_FOR_EACH_PTR(arg);

        token = statement_list(token->next, &stmt->stmts);
        end_function(decl);

        if (!(decl->ctype.modifiers & MOD_INLINE))
                add_symbol(list, decl);
        else if (is_syscall(decl)) {
            add_symbol(list, decl);
            /*
            printf("parse.c decl: %s\n", decl->ident->name);
            char *macro = get_macro_name(decl->pos);
            printf("decl macro: %s\n", macro);
            */
        }
        check_declaration(decl);
        decl->definition = decl;
        prev = decl->same_symbol;
        if (prev && prev->definition) {
                warning(decl->pos, "multiple definitions for function '%s'",
                        show_ident(decl->ident));
                info(prev->definition->pos, " the previous one is here");
        } else {
                while (prev) {
                        rebind_scope(prev, decl->scope);
                        prev->definition = decl;
                        prev = prev->same_symbol;
                }
        }
        function_symbol_list = old_symbol_list;
        if (function_computed_goto_list) {
                if (!function_computed_target_list)
                        warning(decl->pos, "function '%s' has computed goto but no targets?", show_ident(decl->ident));
                else {
                        FOR_EACH_PTR(function_computed_goto_list, stmt) {
                                stmt->target_list = function_computed_target_list;
                        } END_FOR_EACH_PTR(stmt);
                }
        }
        return expect(token, '}', "at end of function");
}

static void promote_k_r_types(struct symbol *arg)
{
        struct symbol *base = arg->ctype.base_type;
        if (base && base->ctype.base_type == &int_type && base->rank < 0) {
                arg->ctype.base_type = &int_ctype;
        }
}

static void apply_k_r_types(struct symbol_list *argtypes, struct symbol *fn)
{
        struct symbol_list *real_args = fn->ctype.base_type->arguments;
        struct symbol *arg;

        FOR_EACH_PTR(real_args, arg) {
                struct symbol *type;

                /* This is quadratic in the number of arguments. We _really_ don't care */
                FOR_EACH_PTR(argtypes, type) {
                        if (type->ident == arg->ident)
                                goto match;
                } END_FOR_EACH_PTR(type);
                if (Wimplicit_int) {
                        warning(arg->pos, "missing type declaration for parameter '%s'",
                                show_ident(arg->ident));
                }
                type = alloc_symbol(arg->pos, SYM_NODE);
                type->ident = arg->ident;
                type->ctype.base_type = &int_ctype;
match:
                type->used = 1;
                /* "char" and "short" promote to "int" */
                promote_k_r_types(type);

                arg->ctype = type->ctype;
        } END_FOR_EACH_PTR(arg);

        FOR_EACH_PTR(argtypes, arg) {
                if (!arg->used)
                        warning(arg->pos, "nonsensical parameter declaration '%s'", show_ident(arg->ident));
        } END_FOR_EACH_PTR(arg);

}

static struct token *parse_k_r_arguments(struct token *token, struct symbol *decl,
        struct symbol_list **list)
{
        struct symbol_list *args = NULL;

        if (Wold_style_definition)
                warning(token->pos, "non-ANSI definition of function '%s'", show_ident(decl->ident));

        do {
                token = declaration_list(token, &args);
                if (!match_op(token, ';')) {
                        sparse_error(token->pos, "expected ';' at end of parameter declaration");
                        break;
                }
                token = token->next;
        } while (lookup_type(token));

        apply_k_r_types(args, decl);

        if (!match_op(token, '{')) {
                sparse_error(token->pos, "expected function body");
                return token;
        }
        return parse_function_body(token, decl, list);
}

static struct token *toplevel_asm_declaration(struct token *token, struct symbol_list **list)
{
        struct symbol *anon = alloc_symbol(token->pos, SYM_NODE);
        struct symbol *fn = alloc_symbol(token->pos, SYM_FN);
        struct statement *stmt;

        anon->ctype.base_type = fn;
        stmt = alloc_statement(token->pos, STMT_NONE);
        fn->stmt = stmt;

        token = parse_asm_statement(token, stmt);

        // FIXME: add_symbol(list, anon);
        return token;
}

struct token *external_declaration(struct token *token, struct symbol_list **list,
                validate_decl_t validate_decl)
{
        struct ident *ident = NULL;
        struct symbol *decl;
        struct decl_state ctx = { .ident = &ident };
        struct ctype saved;
        struct symbol *base_type;
        unsigned long mod;
        int is_typedef;

        if (match_ident(token, &_Pragma_ident))
                return parse_underscore_Pragma(token);

        /* Top-level inline asm or static assertion? */
        if (token_type(token) == TOKEN_IDENT) {
                struct symbol *s = lookup_keyword(token->ident, NS_KEYWORD);
                if (s && s->op->toplevel)
                        return s->op->toplevel(token, list);
        }

        /* Parse declaration-specifiers, if any */
        token = declaration_specifiers(token, &ctx);
        mod = decl_modifiers(&ctx);
        decl = alloc_symbol(token->pos, SYM_NODE);
        /* Just a type declaration? */
        if (match_op(token, ';')) {
                apply_modifiers(token->pos, &ctx);
                return token->next;
        }

        saved = ctx.ctype;
        token = declarator(token, &ctx);
        token = handle_asm_name(token, &ctx);
        token = handle_attributes(token, &ctx);
        apply_modifiers(token->pos, &ctx);

        decl->ctype = ctx.ctype;
        decl->ctype.modifiers |= mod;
        decl->endpos = token->pos;

        /* Just a type declaration? */
        if (!ident) {
                warning(token->pos, "missing identifier in declaration");
                return expect(token, ';', "at the end of type declaration");
        }

        /* type define declaration? */
        is_typedef = ctx.storage_class == MOD_USERTYPE;

        /* Typedefs don't have meaningful storage */
        if (is_typedef)
                decl->ctype.modifiers |= MOD_USERTYPE;

        bind_symbol(decl, ident, is_typedef ? NS_TYPEDEF: NS_SYMBOL);

        base_type = decl->ctype.base_type;

        if (is_typedef) {
                if (base_type && !base_type->ident) {
                        switch (base_type->type) {
                        case SYM_STRUCT:
                        case SYM_UNION:
                        case SYM_ENUM:
                        case SYM_RESTRICT:
                                base_type->ident = ident;
                                break;
                        default:
                                break;
                        }
                }
        } else if (base_type && base_type->type == SYM_FN) {
                if (base_type->ctype.base_type == &autotype_ctype) {
                        sparse_error(decl->pos, "'%s()' has __auto_type return type",
                                show_ident(decl->ident));
                        base_type->ctype.base_type = &int_ctype;
                }
                if (base_type->ctype.base_type == &incomplete_ctype) {
                        warning(decl->pos, "'%s()' has implicit return type",
                                show_ident(decl->ident));
                        base_type->ctype.base_type = &int_ctype;
                }
                /* apply attributes placed after the declarator */
                decl->ctype.modifiers |= ctx.f_modifiers;

                /* K&R argument declaration? */
                if (lookup_type(token))
                        return parse_k_r_arguments(token, decl, list);
                if (match_op(token, '{'))
                        return parse_function_body(token, decl, list);

                if (!(decl->ctype.modifiers & MOD_STATIC))
                        decl->ctype.modifiers |= MOD_EXTERN;
        } else if (base_type == &void_ctype && !(decl->ctype.modifiers & MOD_EXTERN)) {
                sparse_error(token->pos, "void declaration");
        }
        if (base_type == &incomplete_ctype) {
                warning(decl->pos, "'%s' has implicit type", show_ident(decl->ident));
                decl->ctype.base_type = &int_ctype;;
        }

        for (;;) {
                if (!is_typedef && match_op(token, '=')) {
                        struct token *next = token->next;
                        token = initializer(&decl->initializer, next);
                        if (token == next)
                                sparse_error(token->pos, "expression expected before '%s'", show_token(token));
                }
                if (!is_typedef) {
                        if (validate_decl)
                                validate_decl(decl);

                        if (decl->initializer && decl->ctype.modifiers & MOD_EXTERN) {
                                warning(decl->pos, "symbol with external linkage has initializer");
                                decl->ctype.modifiers &= ~MOD_EXTERN;
                        }

                        if (!(decl->ctype.modifiers & (MOD_EXTERN | MOD_INLINE))) {
                                add_symbol(list, decl);
                                fn_local_symbol(decl);
                        }
                }
                check_declaration(decl);
                if (decl->same_symbol) {
                        decl->definition = decl->same_symbol->definition;
                        decl->op = decl->same_symbol->op;
                        if (is_typedef) {
                                // TODO: handle -std=c89 --pedantic
                                check_duplicates(decl);
                        }
                }

                if (ctx.autotype) {
                        const char *msg = NULL;
                        if (decl->ctype.base_type != &autotype_ctype)
                                msg = "on non-identifier";
                        else if (match_op(token, ','))
                                msg = "on declaration list";
                        else if (!decl->initializer)
                                msg = "without initializer";
                        else if (decl->initializer->type == EXPR_SYMBOL &&
                                 decl->initializer->symbol == decl)
                                msg = "on self-init var";
                        if (msg) {
                                sparse_error(decl->pos, "__auto_type %s", msg);
                                decl->ctype.base_type = &bad_ctype;
                        }
                }

                if (!match_op(token, ','))
                        break;

                token = token->next;
                ident = NULL;
                decl = alloc_symbol(token->pos, SYM_NODE);
                ctx.ctype = saved;
                token = handle_attributes(token, &ctx);
                token = declarator(token, &ctx);
                token = handle_asm_name(token, &ctx);
                token = handle_attributes(token, &ctx);
                apply_modifiers(token->pos, &ctx);
                decl->ctype = ctx.ctype;
                decl->ctype.modifiers |= mod;
                decl->endpos = token->pos;
                if (!ident) {
                        sparse_error(token->pos, "expected identifier name in type definition");
                        return token;
                }

                if (is_typedef)
                        decl->ctype.modifiers |= MOD_USERTYPE;

                bind_symbol(decl, ident, is_typedef ? NS_TYPEDEF: NS_SYMBOL);

                /* Function declarations are automatically extern unless specifically static */
                base_type = decl->ctype.base_type;
                if (!is_typedef && base_type && base_type->type == SYM_FN) {
                        if (!(decl->ctype.modifiers & MOD_STATIC))
                                decl->ctype.modifiers |= MOD_EXTERN;
                }
        }
        return expect(token, ';', "at end of declaration");
}