From 0f232d8eaee1f94896596a9969982297cee7dc67 Mon Sep 17 00:00:00 2001 From: Michael Smith Date: Wed, 29 Dec 2021 18:33:40 +0000 Subject: Remove some unused files --- src/3p/chibicc/parse.c | 3368 ------------------------------------------------ 1 file changed, 3368 deletions(-) delete mode 100644 src/3p/chibicc/parse.c (limited to 'src/3p/chibicc/parse.c') diff --git a/src/3p/chibicc/parse.c b/src/3p/chibicc/parse.c deleted file mode 100644 index 6acaeb8..0000000 --- a/src/3p/chibicc/parse.c +++ /dev/null @@ -1,3368 +0,0 @@ -// This file contains a recursive descent parser for C. -// -// Most functions in this file are named after the symbols they are -// supposed to read from an input token list. For example, stmt() is -// responsible for reading a statement from a token list. The function -// then construct an AST node representing a statement. -// -// Each function conceptually returns two values, an AST node and -// remaining part of the input tokens. Since C doesn't support -// multiple return values, the remaining tokens are returned to the -// caller via a pointer argument. -// -// Input tokens are represented by a linked list. Unlike many recursive -// descent parsers, we don't have the notion of the "input token stream". -// Most parsing functions don't change the global state of the parser. -// So it is very easy to lookahead arbitrary number of tokens in this -// parser. - -#include "chibicc.h" - -// Scope for local variables, global variables, typedefs -// or enum constants -typedef struct { - Obj *var; - Type *type_def; - Type *enum_ty; - int enum_val; -} VarScope; - -// Represents a block scope. -typedef struct Scope Scope; -struct Scope { - Scope *next; - - // C has two block scopes; one is for variables/typedefs and - // the other is for struct/union/enum tags. - HashMap vars; - HashMap tags; -}; - -// Variable attributes such as typedef or extern. -typedef struct { - bool is_typedef; - bool is_static; - bool is_extern; - bool is_inline; - bool is_tls; - int align; -} VarAttr; - -// This struct represents a variable initializer. Since initializers -// can be nested (e.g. `int x[2][2] = {{1, 2}, {3, 4}}`), this struct -// is a tree data structure. -typedef struct Initializer Initializer; -struct Initializer { - Initializer *next; - Type *ty; - Token *tok; - bool is_flexible; - - // If it's not an aggregate type and has an initializer, - // `expr` has an initialization expression. - Node *expr; - - // If it's an initializer for an aggregate type (e.g. array or struct), - // `children` has initializers for its children. - Initializer **children; - - // Only one member can be initialized for a union. - // `mem` is used to clarify which member is initialized. - Member *mem; -}; - -// For local variable initializer. -typedef struct InitDesg InitDesg; -struct InitDesg { - InitDesg *next; - int idx; - Member *member; - Obj *var; -}; - -// All local variable instances created during parsing are -// accumulated to this list. -static Obj *locals; - -// Likewise, global variables are accumulated to this list. -static Obj *globals; - -static Scope *scope = &(Scope){}; - -// Points to the function object the parser is currently parsing. -static Obj *current_fn; - -// Lists of all goto statements and labels in the curent function. -static Node *gotos; -static Node *labels; - -// Current "goto" and "continue" jump targets. -static char *brk_label; -static char *cont_label; - -// Points to a node representing a switch if we are parsing -// a switch statement. Otherwise, NULL. -static Node *current_switch; - -static Obj *builtin_alloca; - -static bool is_typename(Token *tok); -static Type *declspec(Token **rest, Token *tok, VarAttr *attr); -static Type *typename(Token **rest, Token *tok); -static Type *enum_specifier(Token **rest, Token *tok); -static Type *typeof_specifier(Token **rest, Token *tok); -static Type *type_suffix(Token **rest, Token *tok, Type *ty); -static Type *declarator(Token **rest, Token *tok, Type *ty); -static Node *declaration(Token **rest, Token *tok, Type *basety, VarAttr *attr); -static void array_initializer2(Token **rest, Token *tok, Initializer *init, int i); -static void struct_initializer2(Token **rest, Token *tok, Initializer *init, Member *mem); -static void initializer2(Token **rest, Token *tok, Initializer *init); -static Initializer *initializer(Token **rest, Token *tok, Type *ty, Type **new_ty); -static Node *lvar_initializer(Token **rest, Token *tok, Obj *var); -static void gvar_initializer(Token **rest, Token *tok, Obj *var); -static Node *compound_stmt(Token **rest, Token *tok); -static Node *stmt(Token **rest, Token *tok); -static Node *expr_stmt(Token **rest, Token *tok); -static Node *expr(Token **rest, Token *tok); -static int64_t eval(Node *node); -static int64_t eval2(Node *node, char ***label); -static int64_t eval_rval(Node *node, char ***label); -static bool is_const_expr(Node *node); -static Node *assign(Token **rest, Token *tok); -static Node *logor(Token **rest, Token *tok); -static double eval_double(Node *node); -static Node *conditional(Token **rest, Token *tok); -static Node *logand(Token **rest, Token *tok); -static Node *bitor(Token **rest, Token *tok); -static Node *bitxor(Token **rest, Token *tok); -static Node *bitand(Token **rest, Token *tok); -static Node *equality(Token **rest, Token *tok); -static Node *relational(Token **rest, Token *tok); -static Node *shift(Token **rest, Token *tok); -static Node *add(Token **rest, Token *tok); -static Node *new_add(Node *lhs, Node *rhs, Token *tok); -static Node *new_sub(Node *lhs, Node *rhs, Token *tok); -static Node *mul(Token **rest, Token *tok); -static Node *cast(Token **rest, Token *tok); -static Member *get_struct_member(Type *ty, Token *tok); -static Type *struct_decl(Token **rest, Token *tok); -static Type *union_decl(Token **rest, Token *tok); -static Node *postfix(Token **rest, Token *tok); -static Node *funcall(Token **rest, Token *tok, Node *node); -static Node *unary(Token **rest, Token *tok); -static Node *primary(Token **rest, Token *tok); -static Token *parse_typedef(Token *tok, Type *basety); -static bool is_function(Token *tok); -static Token *function(Token *tok, Type *basety, VarAttr *attr); -static Token *global_variable(Token *tok, Type *basety, VarAttr *attr); - -static int align_down(int n, int align) { - return align_to(n - align + 1, align); -} - -static void enter_scope(void) { - Scope *sc = calloc(1, sizeof(Scope)); - sc->next = scope; - scope = sc; -} - -static void leave_scope(void) { - scope = scope->next; -} - -// Find a variable by name. -static VarScope *find_var(Token *tok) { - for (Scope *sc = scope; sc; sc = sc->next) { - VarScope *sc2 = hashmap_get2(&sc->vars, tok->loc, tok->len); - if (sc2) - return sc2; - } - return NULL; -} - -static Type *find_tag(Token *tok) { - for (Scope *sc = scope; sc; sc = sc->next) { - Type *ty = hashmap_get2(&sc->tags, tok->loc, tok->len); - if (ty) - return ty; - } - return NULL; -} - -static Node *new_node(NodeKind kind, Token *tok) { - Node *node = calloc(1, sizeof(Node)); - node->kind = kind; - node->tok = tok; - return node; -} - -static Node *new_binary(NodeKind kind, Node *lhs, Node *rhs, Token *tok) { - Node *node = new_node(kind, tok); - node->lhs = lhs; - node->rhs = rhs; - return node; -} - -static Node *new_unary(NodeKind kind, Node *expr, Token *tok) { - Node *node = new_node(kind, tok); - node->lhs = expr; - return node; -} - -static Node *new_num(int64_t val, Token *tok) { - Node *node = new_node(ND_NUM, tok); - node->val = val; - return node; -} - -static Node *new_long(int64_t val, Token *tok) { - Node *node = new_node(ND_NUM, tok); - node->val = val; - node->ty = ty_long; - return node; -} - -static Node *new_ulong(long val, Token *tok) { - Node *node = new_node(ND_NUM, tok); - node->val = val; - node->ty = ty_ulong; - return node; -} - -static Node *new_var_node(Obj *var, Token *tok) { - Node *node = new_node(ND_VAR, tok); - node->var = var; - return node; -} - -static Node *new_vla_ptr(Obj *var, Token *tok) { - Node *node = new_node(ND_VLA_PTR, tok); - node->var = var; - return node; -} - -Node *new_cast(Node *expr, Type *ty) { - add_type(expr); - - Node *node = calloc(1, sizeof(Node)); - node->kind = ND_CAST; - node->tok = expr->tok; - node->lhs = expr; - node->ty = copy_type(ty); - return node; -} - -static VarScope *push_scope(char *name) { - VarScope *sc = calloc(1, sizeof(VarScope)); - hashmap_put(&scope->vars, name, sc); - return sc; -} - -static Initializer *new_initializer(Type *ty, bool is_flexible) { - Initializer *init = calloc(1, sizeof(Initializer)); - init->ty = ty; - - if (ty->kind == TY_ARRAY) { - if (is_flexible && ty->size < 0) { - init->is_flexible = true; - return init; - } - - init->children = calloc(ty->array_len, sizeof(Initializer *)); - for (int i = 0; i < ty->array_len; i++) - init->children[i] = new_initializer(ty->base, false); - return init; - } - - if (ty->kind == TY_STRUCT || ty->kind == TY_UNION) { - // Count the number of struct members. - int len = 0; - for (Member *mem = ty->members; mem; mem = mem->next) - len++; - - init->children = calloc(len, sizeof(Initializer *)); - - for (Member *mem = ty->members; mem; mem = mem->next) { - if (is_flexible && ty->is_flexible && !mem->next) { - Initializer *child = calloc(1, sizeof(Initializer)); - child->ty = mem->ty; - child->is_flexible = true; - init->children[mem->idx] = child; - } else { - init->children[mem->idx] = new_initializer(mem->ty, false); - } - } - return init; - } - - return init; -} - -static Obj *new_var(char *name, Type *ty) { - Obj *var = calloc(1, sizeof(Obj)); - var->name = name; - var->ty = ty; - var->align = ty->align; - push_scope(name)->var = var; - return var; -} - -static Obj *new_lvar(char *name, Type *ty) { - Obj *var = new_var(name, ty); - var->is_local = true; - var->next = locals; - locals = var; - return var; -} - -static Obj *new_gvar(char *name, Type *ty) { - Obj *var = new_var(name, ty); - var->next = globals; - var->is_static = true; - var->is_definition = true; - globals = var; - return var; -} - -static char *new_unique_name(void) { - static int id = 0; - return format(".L..%d", id++); -} - -static Obj *new_anon_gvar(Type *ty) { - return new_gvar(new_unique_name(), ty); -} - -static Obj *new_string_literal(char *p, Type *ty) { - Obj *var = new_anon_gvar(ty); - var->init_data = p; - return var; -} - -static char *get_ident(Token *tok) { - if (tok->kind != TK_IDENT) - error_tok(tok, "expected an identifier"); - return strndup(tok->loc, tok->len); -} - -static Type *find_typedef(Token *tok) { - if (tok->kind == TK_IDENT) { - VarScope *sc = find_var(tok); - if (sc) - return sc->type_def; - } - return NULL; -} - -static void push_tag_scope(Token *tok, Type *ty) { - hashmap_put2(&scope->tags, tok->loc, tok->len, ty); -} - -// declspec = ("void" | "_Bool" | "char" | "short" | "int" | "long" -// | "typedef" | "static" | "extern" | "inline" -// | "_Thread_local" | "__thread" -// | "signed" | "unsigned" -// | struct-decl | union-decl | typedef-name -// | enum-specifier | typeof-specifier -// | "const" | "volatile" | "auto" | "register" | "restrict" -// | "__restrict" | "__restrict__" | "_Noreturn")+ -// -// The order of typenames in a type-specifier doesn't matter. For -// example, `int long static` means the same as `static long int`. -// That can also be written as `static long` because you can omit -// `int` if `long` or `short` are specified. However, something like -// `char int` is not a valid type specifier. We have to accept only a -// limited combinations of the typenames. -// -// In this function, we count the number of occurrences of each typename -// while keeping the "current" type object that the typenames up -// until that point represent. When we reach a non-typename token, -// we returns the current type object. -static Type *declspec(Token **rest, Token *tok, VarAttr *attr) { - // We use a single integer as counters for all typenames. - // For example, bits 0 and 1 represents how many times we saw the - // keyword "void" so far. With this, we can use a switch statement - // as you can see below. - enum { - VOID = 1 << 0, - BOOL = 1 << 2, - CHAR = 1 << 4, - SHORT = 1 << 6, - INT = 1 << 8, - LONG = 1 << 10, - FLOAT = 1 << 12, - DOUBLE = 1 << 14, - OTHER = 1 << 16, - SIGNED = 1 << 17, - UNSIGNED = 1 << 18, - }; - - Type *ty = ty_int; - int counter = 0; - bool is_atomic = false; - - while (is_typename(tok)) { - // Handle storage class specifiers. - if (equal(tok, "typedef") || equal(tok, "static") || equal(tok, "extern") || - equal(tok, "inline") || equal(tok, "_Thread_local") || equal(tok, "__thread")) { - if (!attr) - error_tok(tok, "storage class specifier is not allowed in this context"); - - if (equal(tok, "typedef")) - attr->is_typedef = true; - else if (equal(tok, "static")) - attr->is_static = true; - else if (equal(tok, "extern")) - attr->is_extern = true; - else if (equal(tok, "inline")) - attr->is_inline = true; - else - attr->is_tls = true; - - if (attr->is_typedef && - attr->is_static + attr->is_extern + attr->is_inline + attr->is_tls > 1) - error_tok(tok, "typedef may not be used together with static," - " extern, inline, __thread or _Thread_local"); - tok = tok->next; - continue; - } - - // These keywords are recognized but ignored. - if (consume(&tok, tok, "const") || consume(&tok, tok, "volatile") || - consume(&tok, tok, "auto") || consume(&tok, tok, "register") || - consume(&tok, tok, "restrict") || consume(&tok, tok, "__restrict") || - consume(&tok, tok, "__restrict__") || consume(&tok, tok, "_Noreturn")) - continue; - - if (equal(tok, "_Atomic")) { - tok = tok->next; - if (equal(tok , "(")) { - ty = typename(&tok, tok->next); - tok = skip(tok, ")"); - } - is_atomic = true; - continue; - } - - if (equal(tok, "_Alignas")) { - if (!attr) - error_tok(tok, "_Alignas is not allowed in this context"); - tok = skip(tok->next, "("); - - if (is_typename(tok)) - attr->align = typename(&tok, tok)->align; - else - attr->align = const_expr(&tok, tok); - tok = skip(tok, ")"); - continue; - } - - // Handle user-defined types. - Type *ty2 = find_typedef(tok); - if (equal(tok, "struct") || equal(tok, "union") || equal(tok, "enum") || - equal(tok, "typeof") || ty2) { - if (counter) - break; - - if (equal(tok, "struct")) { - ty = struct_decl(&tok, tok->next); - } else if (equal(tok, "union")) { - ty = union_decl(&tok, tok->next); - } else if (equal(tok, "enum")) { - ty = enum_specifier(&tok, tok->next); - } else if (equal(tok, "typeof")) { - ty = typeof_specifier(&tok, tok->next); - } else { - ty = ty2; - tok = tok->next; - } - - counter += OTHER; - continue; - } - - // Handle built-in types. - if (equal(tok, "void")) - counter += VOID; - else if (equal(tok, "_Bool")) - counter += BOOL; - else if (equal(tok, "char")) - counter += CHAR; - else if (equal(tok, "short")) - counter += SHORT; - else if (equal(tok, "int")) - counter += INT; - else if (equal(tok, "long")) - counter += LONG; - else if (equal(tok, "float")) - counter += FLOAT; - else if (equal(tok, "double")) - counter += DOUBLE; - else if (equal(tok, "signed")) - counter |= SIGNED; - else if (equal(tok, "unsigned")) - counter |= UNSIGNED; - else - unreachable(); - - switch (counter) { - case VOID: - ty = ty_void; - break; - case BOOL: - ty = ty_bool; - break; - case CHAR: - case SIGNED + CHAR: - ty = ty_char; - break; - case UNSIGNED + CHAR: - ty = ty_uchar; - break; - case SHORT: - case SHORT + INT: - case SIGNED + SHORT: - case SIGNED + SHORT + INT: - ty = ty_short; - break; - case UNSIGNED + SHORT: - case UNSIGNED + SHORT + INT: - ty = ty_ushort; - break; - case INT: - case SIGNED: - case SIGNED + INT: - ty = ty_int; - break; - case UNSIGNED: - case UNSIGNED + INT: - ty = ty_uint; - break; - case LONG: - case LONG + INT: - case LONG + LONG: - case LONG + LONG + INT: - case SIGNED + LONG: - case SIGNED + LONG + INT: - case SIGNED + LONG + LONG: - case SIGNED + LONG + LONG + INT: - ty = ty_long; - break; - case UNSIGNED + LONG: - case UNSIGNED + LONG + INT: - case UNSIGNED + LONG + LONG: - case UNSIGNED + LONG + LONG + INT: - ty = ty_ulong; - break; - case FLOAT: - ty = ty_float; - break; - case DOUBLE: - ty = ty_double; - break; - case LONG + DOUBLE: - ty = ty_ldouble; - break; - default: - error_tok(tok, "invalid type"); - } - - tok = tok->next; - } - - if (is_atomic) { - ty = copy_type(ty); - ty->is_atomic = true; - } - - *rest = tok; - return ty; -} - -// func-params = ("void" | param ("," param)* ("," "...")?)? ")" -// param = declspec declarator -static Type *func_params(Token **rest, Token *tok, Type *ty) { - if (equal(tok, "void") && equal(tok->next, ")")) { - *rest = tok->next->next; - return func_type(ty); - } - - Type head = {}; - Type *cur = &head; - bool is_variadic = false; - - while (!equal(tok, ")")) { - if (cur != &head) - tok = skip(tok, ","); - - if (equal(tok, "...")) { - is_variadic = true; - tok = tok->next; - skip(tok, ")"); - break; - } - - Type *ty2 = declspec(&tok, tok, NULL); - ty2 = declarator(&tok, tok, ty2); - - Token *name = ty2->name; - - if (ty2->kind == TY_ARRAY) { - // "array of T" is converted to "pointer to T" only in the parameter - // context. For example, *argv[] is converted to **argv by this. - ty2 = pointer_to(ty2->base); - ty2->name = name; - } else if (ty2->kind == TY_FUNC) { - // Likewise, a function is converted to a pointer to a function - // only in the parameter context. - ty2 = pointer_to(ty2); - ty2->name = name; - } - - cur = cur->next = copy_type(ty2); - } - - if (cur == &head) - is_variadic = true; - - ty = func_type(ty); - ty->params = head.next; - ty->is_variadic = is_variadic; - *rest = tok->next; - return ty; -} - -// array-dimensions = ("static" | "restrict")* const-expr? "]" type-suffix -static Type *array_dimensions(Token **rest, Token *tok, Type *ty) { - while (equal(tok, "static") || equal(tok, "restrict")) - tok = tok->next; - - if (equal(tok, "]")) { - ty = type_suffix(rest, tok->next, ty); - return array_of(ty, -1); - } - - Node *expr = conditional(&tok, tok); - tok = skip(tok, "]"); - ty = type_suffix(rest, tok, ty); - - if (ty->kind == TY_VLA || !is_const_expr(expr)) - return vla_of(ty, expr); - return array_of(ty, eval(expr)); -} - -// type-suffix = "(" func-params -// | "[" array-dimensions -// | ε -static Type *type_suffix(Token **rest, Token *tok, Type *ty) { - if (equal(tok, "(")) - return func_params(rest, tok->next, ty); - - if (equal(tok, "[")) - return array_dimensions(rest, tok->next, ty); - - *rest = tok; - return ty; -} - -// pointers = ("*" ("const" | "volatile" | "restrict")*)* -static Type *pointers(Token **rest, Token *tok, Type *ty) { - while (consume(&tok, tok, "*")) { - ty = pointer_to(ty); - while (equal(tok, "const") || equal(tok, "volatile") || equal(tok, "restrict") || - equal(tok, "__restrict") || equal(tok, "__restrict__")) - tok = tok->next; - } - *rest = tok; - return ty; -} - -// declarator = pointers ("(" ident ")" | "(" declarator ")" | ident) type-suffix -static Type *declarator(Token **rest, Token *tok, Type *ty) { - ty = pointers(&tok, tok, ty); - - if (equal(tok, "(")) { - Token *start = tok; - Type dummy = {}; - declarator(&tok, start->next, &dummy); - tok = skip(tok, ")"); - ty = type_suffix(rest, tok, ty); - return declarator(&tok, start->next, ty); - } - - Token *name = NULL; - Token *name_pos = tok; - - if (tok->kind == TK_IDENT) { - name = tok; - tok = tok->next; - } - - ty = type_suffix(rest, tok, ty); - ty->name = name; - ty->name_pos = name_pos; - return ty; -} - -// abstract-declarator = pointers ("(" abstract-declarator ")")? type-suffix -static Type *abstract_declarator(Token **rest, Token *tok, Type *ty) { - ty = pointers(&tok, tok, ty); - - if (equal(tok, "(")) { - Token *start = tok; - Type dummy = {}; - abstract_declarator(&tok, start->next, &dummy); - tok = skip(tok, ")"); - ty = type_suffix(rest, tok, ty); - return abstract_declarator(&tok, start->next, ty); - } - - return type_suffix(rest, tok, ty); -} - -// type-name = declspec abstract-declarator -static Type *typename(Token **rest, Token *tok) { - Type *ty = declspec(&tok, tok, NULL); - return abstract_declarator(rest, tok, ty); -} - -static bool is_end(Token *tok) { - return equal(tok, "}") || (equal(tok, ",") && equal(tok->next, "}")); -} - -static bool consume_end(Token **rest, Token *tok) { - if (equal(tok, "}")) { - *rest = tok->next; - return true; - } - - if (equal(tok, ",") && equal(tok->next, "}")) { - *rest = tok->next->next; - return true; - } - - return false; -} - -// enum-specifier = ident? "{" enum-list? "}" -// | ident ("{" enum-list? "}")? -// -// enum-list = ident ("=" num)? ("," ident ("=" num)?)* ","? -static Type *enum_specifier(Token **rest, Token *tok) { - Type *ty = enum_type(); - - // Read a struct tag. - Token *tag = NULL; - if (tok->kind == TK_IDENT) { - tag = tok; - tok = tok->next; - } - - if (tag && !equal(tok, "{")) { - Type *ty = find_tag(tag); - if (!ty) - error_tok(tag, "unknown enum type"); - if (ty->kind != TY_ENUM) - error_tok(tag, "not an enum tag"); - *rest = tok; - return ty; - } - - tok = skip(tok, "{"); - - // Read an enum-list. - int i = 0; - int val = 0; - while (!consume_end(rest, tok)) { - if (i++ > 0) - tok = skip(tok, ","); - - char *name = get_ident(tok); - tok = tok->next; - - if (equal(tok, "=")) - val = const_expr(&tok, tok->next); - - VarScope *sc = push_scope(name); - sc->enum_ty = ty; - sc->enum_val = val++; - } - - if (tag) - push_tag_scope(tag, ty); - return ty; -} - -// typeof-specifier = "(" (expr | typename) ")" -static Type *typeof_specifier(Token **rest, Token *tok) { - tok = skip(tok, "("); - - Type *ty; - if (is_typename(tok)) { - ty = typename(&tok, tok); - } else { - Node *node = expr(&tok, tok); - add_type(node); - ty = node->ty; - } - *rest = skip(tok, ")"); - return ty; -} - -// Generate code for computing a VLA size. -static Node *compute_vla_size(Type *ty, Token *tok) { - Node *node = new_node(ND_NULL_EXPR, tok); - if (ty->base) - node = new_binary(ND_COMMA, node, compute_vla_size(ty->base, tok), tok); - - if (ty->kind != TY_VLA) - return node; - - Node *base_sz; - if (ty->base->kind == TY_VLA) - base_sz = new_var_node(ty->base->vla_size, tok); - else - base_sz = new_num(ty->base->size, tok); - - ty->vla_size = new_lvar("", ty_ulong); - Node *expr = new_binary(ND_ASSIGN, new_var_node(ty->vla_size, tok), - new_binary(ND_MUL, ty->vla_len, base_sz, tok), - tok); - return new_binary(ND_COMMA, node, expr, tok); -} - -static Node *new_alloca(Node *sz) { - Node *node = new_unary(ND_FUNCALL, new_var_node(builtin_alloca, sz->tok), sz->tok); - node->func_ty = builtin_alloca->ty; - node->ty = builtin_alloca->ty->return_ty; - node->args = sz; - add_type(sz); - return node; -} - -// declaration = declspec (declarator ("=" expr)? ("," declarator ("=" expr)?)*)? ";" -static Node *declaration(Token **rest, Token *tok, Type *basety, VarAttr *attr) { - Node head = {}; - Node *cur = &head; - int i = 0; - - while (!equal(tok, ";")) { - if (i++ > 0) - tok = skip(tok, ","); - - Type *ty = declarator(&tok, tok, basety); - if (ty->kind == TY_VOID) - error_tok(tok, "variable declared void"); - if (!ty->name) - error_tok(ty->name_pos, "variable name omitted"); - - if (attr && attr->is_static) { - // static local variable - Obj *var = new_anon_gvar(ty); - push_scope(get_ident(ty->name))->var = var; - if (equal(tok, "=")) - gvar_initializer(&tok, tok->next, var); - continue; - } - - // Generate code for computing a VLA size. We need to do this - // even if ty is not VLA because ty may be a pointer to VLA - // (e.g. int (*foo)[n][m] where n and m are variables.) - cur = cur->next = new_unary(ND_EXPR_STMT, compute_vla_size(ty, tok), tok); - - if (ty->kind == TY_VLA) { - if (equal(tok, "=")) - error_tok(tok, "variable-sized object may not be initialized"); - - // Variable length arrays (VLAs) are translated to alloca() calls. - // For example, `int x[n+2]` is translated to `tmp = n + 2, - // x = alloca(tmp)`. - Obj *var = new_lvar(get_ident(ty->name), ty); - Token *tok = ty->name; - Node *expr = new_binary(ND_ASSIGN, new_vla_ptr(var, tok), - new_alloca(new_var_node(ty->vla_size, tok)), - tok); - - cur = cur->next = new_unary(ND_EXPR_STMT, expr, tok); - continue; - } - - Obj *var = new_lvar(get_ident(ty->name), ty); - if (attr && attr->align) - var->align = attr->align; - - if (equal(tok, "=")) { - Node *expr = lvar_initializer(&tok, tok->next, var); - cur = cur->next = new_unary(ND_EXPR_STMT, expr, tok); - } - - if (var->ty->size < 0) - error_tok(ty->name, "variable has incomplete type"); - if (var->ty->kind == TY_VOID) - error_tok(ty->name, "variable declared void"); - } - - Node *node = new_node(ND_BLOCK, tok); - node->body = head.next; - *rest = tok->next; - return node; -} - -static Token *skip_excess_element(Token *tok) { - if (equal(tok, "{")) { - tok = skip_excess_element(tok->next); - return skip(tok, "}"); - } - - assign(&tok, tok); - return tok; -} - -// string-initializer = string-literal -static void string_initializer(Token **rest, Token *tok, Initializer *init) { - if (init->is_flexible) - *init = *new_initializer(array_of(init->ty->base, tok->ty->array_len), false); - - int len = MIN(init->ty->array_len, tok->ty->array_len); - - switch (init->ty->base->size) { - case 1: { - char *str = tok->str; - for (int i = 0; i < len; i++) - init->children[i]->expr = new_num(str[i], tok); - break; - } - case 2: { - uint16_t *str = (uint16_t *)tok->str; - for (int i = 0; i < len; i++) - init->children[i]->expr = new_num(str[i], tok); - break; - } - case 4: { - uint32_t *str = (uint32_t *)tok->str; - for (int i = 0; i < len; i++) - init->children[i]->expr = new_num(str[i], tok); - break; - } - default: - unreachable(); - } - - *rest = tok->next; -} - -// array-designator = "[" const-expr "]" -// -// C99 added the designated initializer to the language, which allows -// programmers to move the "cursor" of an initializer to any element. -// The syntax looks like this: -// -// int x[10] = { 1, 2, [5]=3, 4, 5, 6, 7 }; -// -// `[5]` moves the cursor to the 5th element, so the 5th element of x -// is set to 3. Initialization then continues forward in order, so -// 6th, 7th, 8th and 9th elements are initialized with 4, 5, 6 and 7, -// respectively. Unspecified elements (in this case, 3rd and 4th -// elements) are initialized with zero. -// -// Nesting is allowed, so the following initializer is valid: -// -// int x[5][10] = { [5][8]=1, 2, 3 }; -// -// It sets x[5][8], x[5][9] and x[6][0] to 1, 2 and 3, respectively. -// -// Use `.fieldname` to move the cursor for a struct initializer. E.g. -// -// struct { int a, b, c; } x = { .c=5 }; -// -// The above initializer sets x.c to 5. -static void array_designator(Token **rest, Token *tok, Type *ty, int *begin, int *end) { - *begin = const_expr(&tok, tok->next); - if (*begin >= ty->array_len) - error_tok(tok, "array designator index exceeds array bounds"); - - if (equal(tok, "...")) { - *end = const_expr(&tok, tok->next); - if (*end >= ty->array_len) - error_tok(tok, "array designator index exceeds array bounds"); - if (*end < *begin) - error_tok(tok, "array designator range [%d, %d] is empty", *begin, *end); - } else { - *end = *begin; - } - - *rest = skip(tok, "]"); -} - -// struct-designator = "." ident -static Member *struct_designator(Token **rest, Token *tok, Type *ty) { - Token *start = tok; - tok = skip(tok, "."); - if (tok->kind != TK_IDENT) - error_tok(tok, "expected a field designator"); - - for (Member *mem = ty->members; mem; mem = mem->next) { - // Anonymous struct member - if (mem->ty->kind == TY_STRUCT && !mem->name) { - if (get_struct_member(mem->ty, tok)) { - *rest = start; - return mem; - } - continue; - } - - // Regular struct member - if (mem->name->len == tok->len && !strncmp(mem->name->loc, tok->loc, tok->len)) { - *rest = tok->next; - return mem; - } - } - - error_tok(tok, "struct has no such member"); -} - -// designation = ("[" const-expr "]" | "." ident)* "="? initializer -static void designation(Token **rest, Token *tok, Initializer *init) { - if (equal(tok, "[")) { - if (init->ty->kind != TY_ARRAY) - error_tok(tok, "array index in non-array initializer"); - - int begin, end; - array_designator(&tok, tok, init->ty, &begin, &end); - - Token *tok2; - for (int i = begin; i <= end; i++) - designation(&tok2, tok, init->children[i]); - array_initializer2(rest, tok2, init, begin + 1); - return; - } - - if (equal(tok, ".") && init->ty->kind == TY_STRUCT) { - Member *mem = struct_designator(&tok, tok, init->ty); - designation(&tok, tok, init->children[mem->idx]); - init->expr = NULL; - struct_initializer2(rest, tok, init, mem->next); - return; - } - - if (equal(tok, ".") && init->ty->kind == TY_UNION) { - Member *mem = struct_designator(&tok, tok, init->ty); - init->mem = mem; - designation(rest, tok, init->children[mem->idx]); - return; - } - - if (equal(tok, ".")) - error_tok(tok, "field name not in struct or union initializer"); - - if (equal(tok, "=")) - tok = tok->next; - initializer2(rest, tok, init); -} - -// An array length can be omitted if an array has an initializer -// (e.g. `int x[] = {1,2,3}`). If it's omitted, count the number -// of initializer elements. -static int count_array_init_elements(Token *tok, Type *ty) { - bool first = true; - Initializer *dummy = new_initializer(ty->base, true); - - int i = 0, max = 0; - - while (!consume_end(&tok, tok)) { - if (!first) - tok = skip(tok, ","); - first = false; - - if (equal(tok, "[")) { - i = const_expr(&tok, tok->next); - if (equal(tok, "...")) - i = const_expr(&tok, tok->next); - tok = skip(tok, "]"); - designation(&tok, tok, dummy); - } else { - initializer2(&tok, tok, dummy); - } - - i++; - max = MAX(max, i); - } - return max; -} - -// array-initializer1 = "{" initializer ("," initializer)* ","? "}" -static void array_initializer1(Token **rest, Token *tok, Initializer *init) { - tok = skip(tok, "{"); - - if (init->is_flexible) { - int len = count_array_init_elements(tok, init->ty); - *init = *new_initializer(array_of(init->ty->base, len), false); - } - - bool first = true; - - if (init->is_flexible) { - int len = count_array_init_elements(tok, init->ty); - *init = *new_initializer(array_of(init->ty->base, len), false); - } - - for (int i = 0; !consume_end(rest, tok); i++) { - if (!first) - tok = skip(tok, ","); - first = false; - - if (equal(tok, "[")) { - int begin, end; - array_designator(&tok, tok, init->ty, &begin, &end); - - Token *tok2; - for (int j = begin; j <= end; j++) - designation(&tok2, tok, init->children[j]); - tok = tok2; - i = end; - continue; - } - - if (i < init->ty->array_len) - initializer2(&tok, tok, init->children[i]); - else - tok = skip_excess_element(tok); - } -} - -// array-initializer2 = initializer ("," initializer)* -static void array_initializer2(Token **rest, Token *tok, Initializer *init, int i) { - if (init->is_flexible) { - int len = count_array_init_elements(tok, init->ty); - *init = *new_initializer(array_of(init->ty->base, len), false); - } - - for (; i < init->ty->array_len && !is_end(tok); i++) { - Token *start = tok; - if (i > 0) - tok = skip(tok, ","); - - if (equal(tok, "[") || equal(tok, ".")) { - *rest = start; - return; - } - - initializer2(&tok, tok, init->children[i]); - } - *rest = tok; -} - -// struct-initializer1 = "{" initializer ("," initializer)* ","? "}" -static void struct_initializer1(Token **rest, Token *tok, Initializer *init) { - tok = skip(tok, "{"); - - Member *mem = init->ty->members; - bool first = true; - - while (!consume_end(rest, tok)) { - if (!first) - tok = skip(tok, ","); - first = false; - - if (equal(tok, ".")) { - mem = struct_designator(&tok, tok, init->ty); - designation(&tok, tok, init->children[mem->idx]); - mem = mem->next; - continue; - } - - if (mem) { - initializer2(&tok, tok, init->children[mem->idx]); - mem = mem->next; - } else { - tok = skip_excess_element(tok); - } - } -} - -// struct-initializer2 = initializer ("," initializer)* -static void struct_initializer2(Token **rest, Token *tok, Initializer *init, Member *mem) { - bool first = true; - - for (; mem && !is_end(tok); mem = mem->next) { - Token *start = tok; - - if (!first) - tok = skip(tok, ","); - first = false; - - if (equal(tok, "[") || equal(tok, ".")) { - *rest = start; - return; - } - - initializer2(&tok, tok, init->children[mem->idx]); - } - *rest = tok; -} - -static void union_initializer(Token **rest, Token *tok, Initializer *init) { - // Unlike structs, union initializers take only one initializer, - // and that initializes the first union member by default. - // You can initialize other member using a designated initializer. - if (equal(tok, "{") && equal(tok->next, ".")) { - Member *mem = struct_designator(&tok, tok->next, init->ty); - init->mem = mem; - designation(&tok, tok, init->children[mem->idx]); - *rest = skip(tok, "}"); - return; - } - - init->mem = init->ty->members; - - if (equal(tok, "{")) { - initializer2(&tok, tok->next, init->children[0]); - consume(&tok, tok, ","); - *rest = skip(tok, "}"); - } else { - initializer2(rest, tok, init->children[0]); - } -} - -// initializer = string-initializer | array-initializer -// | struct-initializer | union-initializer -// | assign -static void initializer2(Token **rest, Token *tok, Initializer *init) { - if (init->ty->kind == TY_ARRAY && tok->kind == TK_STR) { - string_initializer(rest, tok, init); - return; - } - - if (init->ty->kind == TY_ARRAY) { - if (equal(tok, "{")) - array_initializer1(rest, tok, init); - else - array_initializer2(rest, tok, init, 0); - return; - } - - if (init->ty->kind == TY_STRUCT) { - if (equal(tok, "{")) { - struct_initializer1(rest, tok, init); - return; - } - - // A struct can be initialized with another struct. E.g. - // `struct T x = y;` where y is a variable of type `struct T`. - // Handle that case first. - Node *expr = assign(rest, tok); - add_type(expr); - if (expr->ty->kind == TY_STRUCT) { - init->expr = expr; - return; - } - - struct_initializer2(rest, tok, init, init->ty->members); - return; - } - - if (init->ty->kind == TY_UNION) { - union_initializer(rest, tok, init); - return; - } - - if (equal(tok, "{")) { - // An initializer for a scalar variable can be surrounded by - // braces. E.g. `int x = {3};`. Handle that case. - initializer2(&tok, tok->next, init); - *rest = skip(tok, "}"); - return; - } - - init->expr = assign(rest, tok); -} - -static Type *copy_struct_type(Type *ty) { - ty = copy_type(ty); - - Member head = {}; - Member *cur = &head; - for (Member *mem = ty->members; mem; mem = mem->next) { - Member *m = calloc(1, sizeof(Member)); - *m = *mem; - cur = cur->next = m; - } - - ty->members = head.next; - return ty; -} - -static Initializer *initializer(Token **rest, Token *tok, Type *ty, Type **new_ty) { - Initializer *init = new_initializer(ty, true); - initializer2(rest, tok, init); - - if ((ty->kind == TY_STRUCT || ty->kind == TY_UNION) && ty->is_flexible) { - ty = copy_struct_type(ty); - - Member *mem = ty->members; - while (mem->next) - mem = mem->next; - mem->ty = init->children[mem->idx]->ty; - ty->size += mem->ty->size; - - *new_ty = ty; - return init; - } - - *new_ty = init->ty; - return init; -} - -static Node *init_desg_expr(InitDesg *desg, Token *tok) { - if (desg->var) - return new_var_node(desg->var, tok); - - if (desg->member) { - Node *node = new_unary(ND_MEMBER, init_desg_expr(desg->next, tok), tok); - node->member = desg->member; - return node; - } - - Node *lhs = init_desg_expr(desg->next, tok); - Node *rhs = new_num(desg->idx, tok); - return new_unary(ND_DEREF, new_add(lhs, rhs, tok), tok); -} - -static Node *create_lvar_init(Initializer *init, Type *ty, InitDesg *desg, Token *tok) { - if (ty->kind == TY_ARRAY) { - Node *node = new_node(ND_NULL_EXPR, tok); - for (int i = 0; i < ty->array_len; i++) { - InitDesg desg2 = {desg, i}; - Node *rhs = create_lvar_init(init->children[i], ty->base, &desg2, tok); - node = new_binary(ND_COMMA, node, rhs, tok); - } - return node; - } - - if (ty->kind == TY_STRUCT && !init->expr) { - Node *node = new_node(ND_NULL_EXPR, tok); - - for (Member *mem = ty->members; mem; mem = mem->next) { - InitDesg desg2 = {desg, 0, mem}; - Node *rhs = create_lvar_init(init->children[mem->idx], mem->ty, &desg2, tok); - node = new_binary(ND_COMMA, node, rhs, tok); - } - return node; - } - - if (ty->kind == TY_UNION) { - Member *mem = init->mem ? init->mem : ty->members; - InitDesg desg2 = {desg, 0, mem}; - return create_lvar_init(init->children[mem->idx], mem->ty, &desg2, tok); - } - - if (!init->expr) - return new_node(ND_NULL_EXPR, tok); - - Node *lhs = init_desg_expr(desg, tok); - return new_binary(ND_ASSIGN, lhs, init->expr, tok); -} - -// A variable definition with an initializer is a shorthand notation -// for a variable definition followed by assignments. This function -// generates assignment expressions for an initializer. For example, -// `int x[2][2] = {{6, 7}, {8, 9}}` is converted to the following -// expressions: -// -// x[0][0] = 6; -// x[0][1] = 7; -// x[1][0] = 8; -// x[1][1] = 9; -static Node *lvar_initializer(Token **rest, Token *tok, Obj *var) { - Initializer *init = initializer(rest, tok, var->ty, &var->ty); - InitDesg desg = {NULL, 0, NULL, var}; - - // If a partial initializer list is given, the standard requires - // that unspecified elements are set to 0. Here, we simply - // zero-initialize the entire memory region of a variable before - // initializing it with user-supplied values. - Node *lhs = new_node(ND_MEMZERO, tok); - lhs->var = var; - - Node *rhs = create_lvar_init(init, var->ty, &desg, tok); - return new_binary(ND_COMMA, lhs, rhs, tok); -} - -static uint64_t read_buf(char *buf, int sz) { - if (sz == 1) - return *buf; - if (sz == 2) - return *(uint16_t *)buf; - if (sz == 4) - return *(uint32_t *)buf; - if (sz == 8) - return *(uint64_t *)buf; - unreachable(); -} - -static void write_buf(char *buf, uint64_t val, int sz) { - if (sz == 1) - *buf = val; - else if (sz == 2) - *(uint16_t *)buf = val; - else if (sz == 4) - *(uint32_t *)buf = val; - else if (sz == 8) - *(uint64_t *)buf = val; - else - unreachable(); -} - -static Relocation * -write_gvar_data(Relocation *cur, Initializer *init, Type *ty, char *buf, int offset) { - if (ty->kind == TY_ARRAY) { - int sz = ty->base->size; - for (int i = 0; i < ty->array_len; i++) - cur = write_gvar_data(cur, init->children[i], ty->base, buf, offset + sz * i); - return cur; - } - - if (ty->kind == TY_STRUCT) { - for (Member *mem = ty->members; mem; mem = mem->next) { - if (mem->is_bitfield) { - Node *expr = init->children[mem->idx]->expr; - if (!expr) - break; - - char *loc = buf + offset + mem->offset; - uint64_t oldval = read_buf(loc, mem->ty->size); - uint64_t newval = eval(expr); - uint64_t mask = (1L << mem->bit_width) - 1; - uint64_t combined = oldval | ((newval & mask) << mem->bit_offset); - write_buf(loc, combined, mem->ty->size); - } else { - cur = write_gvar_data(cur, init->children[mem->idx], mem->ty, buf, - offset + mem->offset); - } - } - return cur; - } - - if (ty->kind == TY_UNION) { - if (!init->mem) - return cur; - return write_gvar_data(cur, init->children[init->mem->idx], - init->mem->ty, buf, offset); - } - - if (!init->expr) - return cur; - - if (ty->kind == TY_FLOAT) { - *(float *)(buf + offset) = eval_double(init->expr); - return cur; - } - - if (ty->kind == TY_DOUBLE) { - *(double *)(buf + offset) = eval_double(init->expr); - return cur; - } - - char **label = NULL; - uint64_t val = eval2(init->expr, &label); - - if (!label) { - write_buf(buf + offset, val, ty->size); - return cur; - } - - Relocation *rel = calloc(1, sizeof(Relocation)); - rel->offset = offset; - rel->label = label; - rel->addend = val; - cur->next = rel; - return cur->next; -} - -// Initializers for global variables are evaluated at compile-time and -// embedded to .data section. This function serializes Initializer -// objects to a flat byte array. It is a compile error if an -// initializer list contains a non-constant expression. -static void gvar_initializer(Token **rest, Token *tok, Obj *var) { - Initializer *init = initializer(rest, tok, var->ty, &var->ty); - - Relocation head = {}; - char *buf = calloc(1, var->ty->size); - write_gvar_data(&head, init, var->ty, buf, 0); - var->init_data = buf; - var->rel = head.next; -} - -// Returns true if a given token represents a type. -static bool is_typename(Token *tok) { - static HashMap map; - - if (map.capacity == 0) { - static char *kw[] = { - "void", "_Bool", "char", "short", "int", "long", "struct", "union", - "typedef", "enum", "static", "extern", "_Alignas", "signed", "unsigned", - "const", "volatile", "auto", "register", "restrict", "__restrict", - "__restrict__", "_Noreturn", "float", "double", "typeof", "inline", - "_Thread_local", "__thread", "_Atomic", - }; - - for (int i = 0; i < sizeof(kw) / sizeof(*kw); i++) - hashmap_put(&map, kw[i], (void *)1); - } - - return hashmap_get2(&map, tok->loc, tok->len) || find_typedef(tok); -} - -// asm-stmt = "asm" ("volatile" | "inline")* "(" string-literal ")" -static Node *asm_stmt(Token **rest, Token *tok) { - Node *node = new_node(ND_ASM, tok); - tok = tok->next; - - while (equal(tok, "volatile") || equal(tok, "inline")) - tok = tok->next; - - tok = skip(tok, "("); - if (tok->kind != TK_STR || tok->ty->base->kind != TY_CHAR) - error_tok(tok, "expected string literal"); - node->asm_str = tok->str; - *rest = skip(tok->next, ")"); - return node; -} - -// stmt = "return" expr? ";" -// | "if" "(" expr ")" stmt ("else" stmt)? -// | "switch" "(" expr ")" stmt -// | "case" const-expr ("..." const-expr)? ":" stmt -// | "default" ":" stmt -// | "for" "(" expr-stmt expr? ";" expr? ")" stmt -// | "while" "(" expr ")" stmt -// | "do" stmt "while" "(" expr ")" ";" -// | "asm" asm-stmt -// | "goto" (ident | "*" expr) ";" -// | "break" ";" -// | "continue" ";" -// | ident ":" stmt -// | "{" compound-stmt -// | expr-stmt -static Node *stmt(Token **rest, Token *tok) { - if (equal(tok, "return")) { - Node *node = new_node(ND_RETURN, tok); - if (consume(rest, tok->next, ";")) - return node; - - Node *exp = expr(&tok, tok->next); - *rest = skip(tok, ";"); - - add_type(exp); - Type *ty = current_fn->ty->return_ty; - if (ty->kind != TY_STRUCT && ty->kind != TY_UNION) - exp = new_cast(exp, current_fn->ty->return_ty); - - node->lhs = exp; - return node; - } - - if (equal(tok, "if")) { - Node *node = new_node(ND_IF, tok); - tok = skip(tok->next, "("); - node->cond = expr(&tok, tok); - tok = skip(tok, ")"); - node->then = stmt(&tok, tok); - if (equal(tok, "else")) - node->els = stmt(&tok, tok->next); - *rest = tok; - return node; - } - - if (equal(tok, "switch")) { - Node *node = new_node(ND_SWITCH, tok); - tok = skip(tok->next, "("); - node->cond = expr(&tok, tok); - tok = skip(tok, ")"); - - Node *sw = current_switch; - current_switch = node; - - char *brk = brk_label; - brk_label = node->brk_label = new_unique_name(); - - node->then = stmt(rest, tok); - - current_switch = sw; - brk_label = brk; - return node; - } - - if (equal(tok, "case")) { - if (!current_switch) - error_tok(tok, "stray case"); - - Node *node = new_node(ND_CASE, tok); - int begin = const_expr(&tok, tok->next); - int end; - - if (equal(tok, "...")) { - // [GNU] Case ranges, e.g. "case 1 ... 5:" - end = const_expr(&tok, tok->next); - if (end < begin) - error_tok(tok, "empty case range specified"); - } else { - end = begin; - } - - tok = skip(tok, ":"); - node->label = new_unique_name(); - node->lhs = stmt(rest, tok); - node->begin = begin; - node->end = end; - node->case_next = current_switch->case_next; - current_switch->case_next = node; - return node; - } - - if (equal(tok, "default")) { - if (!current_switch) - error_tok(tok, "stray default"); - - Node *node = new_node(ND_CASE, tok); - tok = skip(tok->next, ":"); - node->label = new_unique_name(); - node->lhs = stmt(rest, tok); - current_switch->default_case = node; - return node; - } - - if (equal(tok, "for")) { - Node *node = new_node(ND_FOR, tok); - tok = skip(tok->next, "("); - - enter_scope(); - - char *brk = brk_label; - char *cont = cont_label; - brk_label = node->brk_label = new_unique_name(); - cont_label = node->cont_label = new_unique_name(); - - if (is_typename(tok)) { - Type *basety = declspec(&tok, tok, NULL); - node->init = declaration(&tok, tok, basety, NULL); - } else { - node->init = expr_stmt(&tok, tok); - } - - if (!equal(tok, ";")) - node->cond = expr(&tok, tok); - tok = skip(tok, ";"); - - if (!equal(tok, ")")) - node->inc = expr(&tok, tok); - tok = skip(tok, ")"); - - node->then = stmt(rest, tok); - - leave_scope(); - brk_label = brk; - cont_label = cont; - return node; - } - - if (equal(tok, "while")) { - Node *node = new_node(ND_FOR, tok); - tok = skip(tok->next, "("); - node->cond = expr(&tok, tok); - tok = skip(tok, ")"); - - char *brk = brk_label; - char *cont = cont_label; - brk_label = node->brk_label = new_unique_name(); - cont_label = node->cont_label = new_unique_name(); - - node->then = stmt(rest, tok); - - brk_label = brk; - cont_label = cont; - return node; - } - - if (equal(tok, "do")) { - Node *node = new_node(ND_DO, tok); - - char *brk = brk_label; - char *cont = cont_label; - brk_label = node->brk_label = new_unique_name(); - cont_label = node->cont_label = new_unique_name(); - - node->then = stmt(&tok, tok->next); - - brk_label = brk; - cont_label = cont; - - tok = skip(tok, "while"); - tok = skip(tok, "("); - node->cond = expr(&tok, tok); - tok = skip(tok, ")"); - *rest = skip(tok, ";"); - return node; - } - - if (equal(tok, "asm")) - return asm_stmt(rest, tok); - - if (equal(tok, "goto")) { - if (equal(tok->next, "*")) { - // [GNU] `goto *ptr` jumps to the address specified by `ptr`. - Node *node = new_node(ND_GOTO_EXPR, tok); - node->lhs = expr(&tok, tok->next->next); - *rest = skip(tok, ";"); - return node; - } - - Node *node = new_node(ND_GOTO, tok); - node->label = get_ident(tok->next); - node->goto_next = gotos; - gotos = node; - *rest = skip(tok->next->next, ";"); - return node; - } - - if (equal(tok, "break")) { - if (!brk_label) - error_tok(tok, "stray break"); - Node *node = new_node(ND_GOTO, tok); - node->unique_label = brk_label; - *rest = skip(tok->next, ";"); - return node; - } - - if (equal(tok, "continue")) { - if (!cont_label) - error_tok(tok, "stray continue"); - Node *node = new_node(ND_GOTO, tok); - node->unique_label = cont_label; - *rest = skip(tok->next, ";"); - return node; - } - - if (tok->kind == TK_IDENT && equal(tok->next, ":")) { - Node *node = new_node(ND_LABEL, tok); - node->label = strndup(tok->loc, tok->len); - node->unique_label = new_unique_name(); - node->lhs = stmt(rest, tok->next->next); - node->goto_next = labels; - labels = node; - return node; - } - - if (equal(tok, "{")) - return compound_stmt(rest, tok->next); - - return expr_stmt(rest, tok); -} - -// compound-stmt = (typedef | declaration | stmt)* "}" -static Node *compound_stmt(Token **rest, Token *tok) { - Node *node = new_node(ND_BLOCK, tok); - Node head = {}; - Node *cur = &head; - - enter_scope(); - - while (!equal(tok, "}")) { - if (is_typename(tok) && !equal(tok->next, ":")) { - VarAttr attr = {}; - Type *basety = declspec(&tok, tok, &attr); - - if (attr.is_typedef) { - tok = parse_typedef(tok, basety); - continue; - } - - if (is_function(tok)) { - tok = function(tok, basety, &attr); - continue; - } - - if (attr.is_extern) { - tok = global_variable(tok, basety, &attr); - continue; - } - - cur = cur->next = declaration(&tok, tok, basety, &attr); - } else { - cur = cur->next = stmt(&tok, tok); - } - add_type(cur); - } - - leave_scope(); - - node->body = head.next; - *rest = tok->next; - return node; -} - -// expr-stmt = expr? ";" -static Node *expr_stmt(Token **rest, Token *tok) { - if (equal(tok, ";")) { - *rest = tok->next; - return new_node(ND_BLOCK, tok); - } - - Node *node = new_node(ND_EXPR_STMT, tok); - node->lhs = expr(&tok, tok); - *rest = skip(tok, ";"); - return node; -} - -// expr = assign ("," expr)? -static Node *expr(Token **rest, Token *tok) { - Node *node = assign(&tok, tok); - - if (equal(tok, ",")) - return new_binary(ND_COMMA, node, expr(rest, tok->next), tok); - - *rest = tok; - return node; -} - -static int64_t eval(Node *node) { - return eval2(node, NULL); -} - -// Evaluate a given node as a constant expression. -// -// A constant expression is either just a number or ptr+n where ptr -// is a pointer to a global variable and n is a postiive/negative -// number. The latter form is accepted only as an initialization -// expression for a global variable. -static int64_t eval2(Node *node, char ***label) { - add_type(node); - - if (is_flonum(node->ty)) - return eval_double(node); - - switch (node->kind) { - case ND_ADD: - return eval2(node->lhs, label) + eval(node->rhs); - case ND_SUB: - return eval2(node->lhs, label) - eval(node->rhs); - case ND_MUL: - return eval(node->lhs) * eval(node->rhs); - case ND_DIV: - if (node->ty->is_unsigned) - return (uint64_t)eval(node->lhs) / eval(node->rhs); - return eval(node->lhs) / eval(node->rhs); - case ND_NEG: - return -eval(node->lhs); - case ND_MOD: - if (node->ty->is_unsigned) - return (uint64_t)eval(node->lhs) % eval(node->rhs); - return eval(node->lhs) % eval(node->rhs); - case ND_BITAND: - return eval(node->lhs) & eval(node->rhs); - case ND_BITOR: - return eval(node->lhs) | eval(node->rhs); - case ND_BITXOR: - return eval(node->lhs) ^ eval(node->rhs); - case ND_SHL: - return eval(node->lhs) << eval(node->rhs); - case ND_SHR: - if (node->ty->is_unsigned && node->ty->size == 8) - return (uint64_t)eval(node->lhs) >> eval(node->rhs); - return eval(node->lhs) >> eval(node->rhs); - case ND_EQ: - return eval(node->lhs) == eval(node->rhs); - case ND_NE: - return eval(node->lhs) != eval(node->rhs); - case ND_LT: - if (node->lhs->ty->is_unsigned) - return (uint64_t)eval(node->lhs) < eval(node->rhs); - return eval(node->lhs) < eval(node->rhs); - case ND_LE: - if (node->lhs->ty->is_unsigned) - return (uint64_t)eval(node->lhs) <= eval(node->rhs); - return eval(node->lhs) <= eval(node->rhs); - case ND_COND: - return eval(node->cond) ? eval2(node->then, label) : eval2(node->els, label); - case ND_COMMA: - return eval2(node->rhs, label); - case ND_NOT: - return !eval(node->lhs); - case ND_BITNOT: - return ~eval(node->lhs); - case ND_LOGAND: - return eval(node->lhs) && eval(node->rhs); - case ND_LOGOR: - return eval(node->lhs) || eval(node->rhs); - case ND_CAST: { - int64_t val = eval2(node->lhs, label); - if (is_integer(node->ty)) { - switch (node->ty->size) { - case 1: return node->ty->is_unsigned ? (uint8_t)val : (int8_t)val; - case 2: return node->ty->is_unsigned ? (uint16_t)val : (int16_t)val; - case 4: return node->ty->is_unsigned ? (uint32_t)val : (int32_t)val; - } - } - return val; - } - case ND_ADDR: - return eval_rval(node->lhs, label); - case ND_LABEL_VAL: - *label = &node->unique_label; - return 0; - case ND_MEMBER: - if (!label) - error_tok(node->tok, "not a compile-time constant"); - if (node->ty->kind != TY_ARRAY) - error_tok(node->tok, "invalid initializer"); - return eval_rval(node->lhs, label) + node->member->offset; - case ND_VAR: - if (!label) - error_tok(node->tok, "not a compile-time constant"); - if (node->var->ty->kind != TY_ARRAY && node->var->ty->kind != TY_FUNC) - error_tok(node->tok, "invalid initializer"); - *label = &node->var->name; - return 0; - case ND_NUM: - return node->val; - } - - error_tok(node->tok, "not a compile-time constant"); -} - -static int64_t eval_rval(Node *node, char ***label) { - switch (node->kind) { - case ND_VAR: - if (node->var->is_local) - error_tok(node->tok, "not a compile-time constant"); - *label = &node->var->name; - return 0; - case ND_DEREF: - return eval2(node->lhs, label); - case ND_MEMBER: - return eval_rval(node->lhs, label) + node->member->offset; - } - - error_tok(node->tok, "invalid initializer"); -} - -static bool is_const_expr(Node *node) { - add_type(node); - - switch (node->kind) { - case ND_ADD: - case ND_SUB: - case ND_MUL: - case ND_DIV: - case ND_BITAND: - case ND_BITOR: - case ND_BITXOR: - case ND_SHL: - case ND_SHR: - case ND_EQ: - case ND_NE: - case ND_LT: - case ND_LE: - case ND_LOGAND: - case ND_LOGOR: - return is_const_expr(node->lhs) && is_const_expr(node->rhs); - case ND_COND: - if (!is_const_expr(node->cond)) - return false; - return is_const_expr(eval(node->cond) ? node->then : node->els); - case ND_COMMA: - return is_const_expr(node->rhs); - case ND_NEG: - case ND_NOT: - case ND_BITNOT: - case ND_CAST: - return is_const_expr(node->lhs); - case ND_NUM: - return true; - } - - return false; -} - -int64_t const_expr(Token **rest, Token *tok) { - Node *node = conditional(rest, tok); - return eval(node); -} - -static double eval_double(Node *node) { - add_type(node); - - if (is_integer(node->ty)) { - if (node->ty->is_unsigned) - return (unsigned long)eval(node); - return eval(node); - } - - switch (node->kind) { - case ND_ADD: - return eval_double(node->lhs) + eval_double(node->rhs); - case ND_SUB: - return eval_double(node->lhs) - eval_double(node->rhs); - case ND_MUL: - return eval_double(node->lhs) * eval_double(node->rhs); - case ND_DIV: - return eval_double(node->lhs) / eval_double(node->rhs); - case ND_NEG: - return -eval_double(node->lhs); - case ND_COND: - return eval_double(node->cond) ? eval_double(node->then) : eval_double(node->els); - case ND_COMMA: - return eval_double(node->rhs); - case ND_CAST: - if (is_flonum(node->lhs->ty)) - return eval_double(node->lhs); - return eval(node->lhs); - case ND_NUM: - return node->fval; - } - - error_tok(node->tok, "not a compile-time constant"); -} - -// Convert op= operators to expressions containing an assignment. -// -// In general, `A op= C` is converted to ``tmp = &A, *tmp = *tmp op B`. -// However, if a given expression is of form `A.x op= C`, the input is -// converted to `tmp = &A, (*tmp).x = (*tmp).x op C` to handle assignments -// to bitfields. -static Node *to_assign(Node *binary) { - add_type(binary->lhs); - add_type(binary->rhs); - Token *tok = binary->tok; - - // Convert `A.x op= C` to `tmp = &A, (*tmp).x = (*tmp).x op C`. - if (binary->lhs->kind == ND_MEMBER) { - Obj *var = new_lvar("", pointer_to(binary->lhs->lhs->ty)); - - Node *expr1 = new_binary(ND_ASSIGN, new_var_node(var, tok), - new_unary(ND_ADDR, binary->lhs->lhs, tok), tok); - - Node *expr2 = new_unary(ND_MEMBER, - new_unary(ND_DEREF, new_var_node(var, tok), tok), - tok); - expr2->member = binary->lhs->member; - - Node *expr3 = new_unary(ND_MEMBER, - new_unary(ND_DEREF, new_var_node(var, tok), tok), - tok); - expr3->member = binary->lhs->member; - - Node *expr4 = new_binary(ND_ASSIGN, expr2, - new_binary(binary->kind, expr3, binary->rhs, tok), - tok); - - return new_binary(ND_COMMA, expr1, expr4, tok); - } - - // If A is an atomic type, Convert `A op= B` to - // - // ({ - // T1 *addr = &A; T2 val = (B); T1 old = *addr; T1 new; - // do { - // new = old op val; - // } while (!atomic_compare_exchange_strong(addr, &old, new)); - // new; - // }) - if (binary->lhs->ty->is_atomic) { - Node head = {}; - Node *cur = &head; - - Obj *addr = new_lvar("", pointer_to(binary->lhs->ty)); - Obj *val = new_lvar("", binary->rhs->ty); - Obj *old = new_lvar("", binary->lhs->ty); - Obj *new = new_lvar("", binary->lhs->ty); - - cur = cur->next = - new_unary(ND_EXPR_STMT, - new_binary(ND_ASSIGN, new_var_node(addr, tok), - new_unary(ND_ADDR, binary->lhs, tok), tok), - tok); - - cur = cur->next = - new_unary(ND_EXPR_STMT, - new_binary(ND_ASSIGN, new_var_node(val, tok), binary->rhs, tok), - tok); - - cur = cur->next = - new_unary(ND_EXPR_STMT, - new_binary(ND_ASSIGN, new_var_node(old, tok), - new_unary(ND_DEREF, new_var_node(addr, tok), tok), tok), - tok); - - Node *loop = new_node(ND_DO, tok); - loop->brk_label = new_unique_name(); - loop->cont_label = new_unique_name(); - - Node *body = new_binary(ND_ASSIGN, - new_var_node(new, tok), - new_binary(binary->kind, new_var_node(old, tok), - new_var_node(val, tok), tok), - tok); - - loop->then = new_node(ND_BLOCK, tok); - loop->then->body = new_unary(ND_EXPR_STMT, body, tok); - - Node *cas = new_node(ND_CAS, tok); - cas->cas_addr = new_var_node(addr, tok); - cas->cas_old = new_unary(ND_ADDR, new_var_node(old, tok), tok); - cas->cas_new = new_var_node(new, tok); - loop->cond = new_unary(ND_NOT, cas, tok); - - cur = cur->next = loop; - cur = cur->next = new_unary(ND_EXPR_STMT, new_var_node(new, tok), tok); - - Node *node = new_node(ND_STMT_EXPR, tok); - node->body = head.next; - return node; - } - - // Convert `A op= B` to ``tmp = &A, *tmp = *tmp op B`. - Obj *var = new_lvar("", pointer_to(binary->lhs->ty)); - - Node *expr1 = new_binary(ND_ASSIGN, new_var_node(var, tok), - new_unary(ND_ADDR, binary->lhs, tok), tok); - - Node *expr2 = - new_binary(ND_ASSIGN, - new_unary(ND_DEREF, new_var_node(var, tok), tok), - new_binary(binary->kind, - new_unary(ND_DEREF, new_var_node(var, tok), tok), - binary->rhs, - tok), - tok); - - return new_binary(ND_COMMA, expr1, expr2, tok); -} - -// assign = conditional (assign-op assign)? -// assign-op = "=" | "+=" | "-=" | "*=" | "/=" | "%=" | "&=" | "|=" | "^=" -// | "<<=" | ">>=" -static Node *assign(Token **rest, Token *tok) { - Node *node = conditional(&tok, tok); - - if (equal(tok, "=")) - return new_binary(ND_ASSIGN, node, assign(rest, tok->next), tok); - - if (equal(tok, "+=")) - return to_assign(new_add(node, assign(rest, tok->next), tok)); - - if (equal(tok, "-=")) - return to_assign(new_sub(node, assign(rest, tok->next), tok)); - - if (equal(tok, "*=")) - return to_assign(new_binary(ND_MUL, node, assign(rest, tok->next), tok)); - - if (equal(tok, "/=")) - return to_assign(new_binary(ND_DIV, node, assign(rest, tok->next), tok)); - - if (equal(tok, "%=")) - return to_assign(new_binary(ND_MOD, node, assign(rest, tok->next), tok)); - - if (equal(tok, "&=")) - return to_assign(new_binary(ND_BITAND, node, assign(rest, tok->next), tok)); - - if (equal(tok, "|=")) - return to_assign(new_binary(ND_BITOR, node, assign(rest, tok->next), tok)); - - if (equal(tok, "^=")) - return to_assign(new_binary(ND_BITXOR, node, assign(rest, tok->next), tok)); - - if (equal(tok, "<<=")) - return to_assign(new_binary(ND_SHL, node, assign(rest, tok->next), tok)); - - if (equal(tok, ">>=")) - return to_assign(new_binary(ND_SHR, node, assign(rest, tok->next), tok)); - - *rest = tok; - return node; -} - -// conditional = logor ("?" expr? ":" conditional)? -static Node *conditional(Token **rest, Token *tok) { - Node *cond = logor(&tok, tok); - - if (!equal(tok, "?")) { - *rest = tok; - return cond; - } - - if (equal(tok->next, ":")) { - // [GNU] Compile `a ?: b` as `tmp = a, tmp ? tmp : b`. - add_type(cond); - Obj *var = new_lvar("", cond->ty); - Node *lhs = new_binary(ND_ASSIGN, new_var_node(var, tok), cond, tok); - Node *rhs = new_node(ND_COND, tok); - rhs->cond = new_var_node(var, tok); - rhs->then = new_var_node(var, tok); - rhs->els = conditional(rest, tok->next->next); - return new_binary(ND_COMMA, lhs, rhs, tok); - } - - Node *node = new_node(ND_COND, tok); - node->cond = cond; - node->then = expr(&tok, tok->next); - tok = skip(tok, ":"); - node->els = conditional(rest, tok); - return node; -} - -// logor = logand ("||" logand)* -static Node *logor(Token **rest, Token *tok) { - Node *node = logand(&tok, tok); - while (equal(tok, "||")) { - Token *start = tok; - node = new_binary(ND_LOGOR, node, logand(&tok, tok->next), start); - } - *rest = tok; - return node; -} - -// logand = bitor ("&&" bitor)* -static Node *logand(Token **rest, Token *tok) { - Node *node = bitor(&tok, tok); - while (equal(tok, "&&")) { - Token *start = tok; - node = new_binary(ND_LOGAND, node, bitor(&tok, tok->next), start); - } - *rest = tok; - return node; -} - -// bitor = bitxor ("|" bitxor)* -static Node *bitor(Token **rest, Token *tok) { - Node *node = bitxor(&tok, tok); - while (equal(tok, "|")) { - Token *start = tok; - node = new_binary(ND_BITOR, node, bitxor(&tok, tok->next), start); - } - *rest = tok; - return node; -} - -// bitxor = bitand ("^" bitand)* -static Node *bitxor(Token **rest, Token *tok) { - Node *node = bitand(&tok, tok); - while (equal(tok, "^")) { - Token *start = tok; - node = new_binary(ND_BITXOR, node, bitand(&tok, tok->next), start); - } - *rest = tok; - return node; -} - -// bitand = equality ("&" equality)* -static Node *bitand(Token **rest, Token *tok) { - Node *node = equality(&tok, tok); - while (equal(tok, "&")) { - Token *start = tok; - node = new_binary(ND_BITAND, node, equality(&tok, tok->next), start); - } - *rest = tok; - return node; -} - -// equality = relational ("==" relational | "!=" relational)* -static Node *equality(Token **rest, Token *tok) { - Node *node = relational(&tok, tok); - - for (;;) { - Token *start = tok; - - if (equal(tok, "==")) { - node = new_binary(ND_EQ, node, relational(&tok, tok->next), start); - continue; - } - - if (equal(tok, "!=")) { - node = new_binary(ND_NE, node, relational(&tok, tok->next), start); - continue; - } - - *rest = tok; - return node; - } -} - -// relational = shift ("<" shift | "<=" shift | ">" shift | ">=" shift)* -static Node *relational(Token **rest, Token *tok) { - Node *node = shift(&tok, tok); - - for (;;) { - Token *start = tok; - - if (equal(tok, "<")) { - node = new_binary(ND_LT, node, shift(&tok, tok->next), start); - continue; - } - - if (equal(tok, "<=")) { - node = new_binary(ND_LE, node, shift(&tok, tok->next), start); - continue; - } - - if (equal(tok, ">")) { - node = new_binary(ND_LT, shift(&tok, tok->next), node, start); - continue; - } - - if (equal(tok, ">=")) { - node = new_binary(ND_LE, shift(&tok, tok->next), node, start); - continue; - } - - *rest = tok; - return node; - } -} - -// shift = add ("<<" add | ">>" add)* -static Node *shift(Token **rest, Token *tok) { - Node *node = add(&tok, tok); - - for (;;) { - Token *start = tok; - - if (equal(tok, "<<")) { - node = new_binary(ND_SHL, node, add(&tok, tok->next), start); - continue; - } - - if (equal(tok, ">>")) { - node = new_binary(ND_SHR, node, add(&tok, tok->next), start); - continue; - } - - *rest = tok; - return node; - } -} - -// In C, `+` operator is overloaded to perform the pointer arithmetic. -// If p is a pointer, p+n adds not n but sizeof(*p)*n to the value of p, -// so that p+n points to the location n elements (not bytes) ahead of p. -// In other words, we need to scale an integer value before adding to a -// pointer value. This function takes care of the scaling. -static Node *new_add(Node *lhs, Node *rhs, Token *tok) { - add_type(lhs); - add_type(rhs); - - // num + num - if (is_numeric(lhs->ty) && is_numeric(rhs->ty)) - return new_binary(ND_ADD, lhs, rhs, tok); - - if (lhs->ty->base && rhs->ty->base) - error_tok(tok, "invalid operands"); - - // Canonicalize `num + ptr` to `ptr + num`. - if (!lhs->ty->base && rhs->ty->base) { - Node *tmp = lhs; - lhs = rhs; - rhs = tmp; - } - - // VLA + num - if (lhs->ty->base->kind == TY_VLA) { - rhs = new_binary(ND_MUL, rhs, new_var_node(lhs->ty->base->vla_size, tok), tok); - return new_binary(ND_ADD, lhs, rhs, tok); - } - - // ptr + num - rhs = new_binary(ND_MUL, rhs, new_long(lhs->ty->base->size, tok), tok); - return new_binary(ND_ADD, lhs, rhs, tok); -} - -// Like `+`, `-` is overloaded for the pointer type. -static Node *new_sub(Node *lhs, Node *rhs, Token *tok) { - add_type(lhs); - add_type(rhs); - - // num - num - if (is_numeric(lhs->ty) && is_numeric(rhs->ty)) - return new_binary(ND_SUB, lhs, rhs, tok); - - // VLA + num - if (lhs->ty->base->kind == TY_VLA) { - rhs = new_binary(ND_MUL, rhs, new_var_node(lhs->ty->base->vla_size, tok), tok); - add_type(rhs); - Node *node = new_binary(ND_SUB, lhs, rhs, tok); - node->ty = lhs->ty; - return node; - } - - // ptr - num - if (lhs->ty->base && is_integer(rhs->ty)) { - rhs = new_binary(ND_MUL, rhs, new_long(lhs->ty->base->size, tok), tok); - add_type(rhs); - Node *node = new_binary(ND_SUB, lhs, rhs, tok); - node->ty = lhs->ty; - return node; - } - - // ptr - ptr, which returns how many elements are between the two. - if (lhs->ty->base && rhs->ty->base) { - Node *node = new_binary(ND_SUB, lhs, rhs, tok); - node->ty = ty_long; - return new_binary(ND_DIV, node, new_num(lhs->ty->base->size, tok), tok); - } - - error_tok(tok, "invalid operands"); -} - -// add = mul ("+" mul | "-" mul)* -static Node *add(Token **rest, Token *tok) { - Node *node = mul(&tok, tok); - - for (;;) { - Token *start = tok; - - if (equal(tok, "+")) { - node = new_add(node, mul(&tok, tok->next), start); - continue; - } - - if (equal(tok, "-")) { - node = new_sub(node, mul(&tok, tok->next), start); - continue; - } - - *rest = tok; - return node; - } -} - -// mul = cast ("*" cast | "/" cast | "%" cast)* -static Node *mul(Token **rest, Token *tok) { - Node *node = cast(&tok, tok); - - for (;;) { - Token *start = tok; - - if (equal(tok, "*")) { - node = new_binary(ND_MUL, node, cast(&tok, tok->next), start); - continue; - } - - if (equal(tok, "/")) { - node = new_binary(ND_DIV, node, cast(&tok, tok->next), start); - continue; - } - - if (equal(tok, "%")) { - node = new_binary(ND_MOD, node, cast(&tok, tok->next), start); - continue; - } - - *rest = tok; - return node; - } -} - -// cast = "(" type-name ")" cast | unary -static Node *cast(Token **rest, Token *tok) { - if (equal(tok, "(") && is_typename(tok->next)) { - Token *start = tok; - Type *ty = typename(&tok, tok->next); - tok = skip(tok, ")"); - - // compound literal - if (equal(tok, "{")) - return unary(rest, start); - - // type cast - Node *node = new_cast(cast(rest, tok), ty); - node->tok = start; - return node; - } - - return unary(rest, tok); -} - -// unary = ("+" | "-" | "*" | "&" | "!" | "~") cast -// | ("++" | "--") unary -// | "&&" ident -// | postfix -static Node *unary(Token **rest, Token *tok) { - if (equal(tok, "+")) - return cast(rest, tok->next); - - if (equal(tok, "-")) - return new_unary(ND_NEG, cast(rest, tok->next), tok); - - if (equal(tok, "&")) { - Node *lhs = cast(rest, tok->next); - add_type(lhs); - if (lhs->kind == ND_MEMBER && lhs->member->is_bitfield) - error_tok(tok, "cannot take address of bitfield"); - return new_unary(ND_ADDR, lhs, tok); - } - - if (equal(tok, "*")) { - // [https://www.sigbus.info/n1570#6.5.3.2p4] This is an oddity - // in the C spec, but dereferencing a function shouldn't do - // anything. If foo is a function, `*foo`, `**foo` or `*****foo` - // are all equivalent to just `foo`. - Node *node = cast(rest, tok->next); - add_type(node); - if (node->ty->kind == TY_FUNC) - return node; - return new_unary(ND_DEREF, node, tok); - } - - if (equal(tok, "!")) - return new_unary(ND_NOT, cast(rest, tok->next), tok); - - if (equal(tok, "~")) - return new_unary(ND_BITNOT, cast(rest, tok->next), tok); - - // Read ++i as i+=1 - if (equal(tok, "++")) - return to_assign(new_add(unary(rest, tok->next), new_num(1, tok), tok)); - - // Read --i as i-=1 - if (equal(tok, "--")) - return to_assign(new_sub(unary(rest, tok->next), new_num(1, tok), tok)); - - // [GNU] labels-as-values - if (equal(tok, "&&")) { - Node *node = new_node(ND_LABEL_VAL, tok); - node->label = get_ident(tok->next); - node->goto_next = gotos; - gotos = node; - *rest = tok->next->next; - return node; - } - - return postfix(rest, tok); -} - -// struct-members = (declspec declarator ("," declarator)* ";")* -static void struct_members(Token **rest, Token *tok, Type *ty) { - Member head = {}; - Member *cur = &head; - int idx = 0; - - while (!equal(tok, "}")) { - VarAttr attr = {}; - Type *basety = declspec(&tok, tok, &attr); - bool first = true; - - // Anonymous struct member - if ((basety->kind == TY_STRUCT || basety->kind == TY_UNION) && - consume(&tok, tok, ";")) { - Member *mem = calloc(1, sizeof(Member)); - mem->ty = basety; - mem->idx = idx++; - mem->align = attr.align ? attr.align : mem->ty->align; - cur = cur->next = mem; - continue; - } - - // Regular struct members - while (!consume(&tok, tok, ";")) { - if (!first) - tok = skip(tok, ","); - first = false; - - Member *mem = calloc(1, sizeof(Member)); - mem->ty = declarator(&tok, tok, basety); - mem->name = mem->ty->name; - mem->idx = idx++; - mem->align = attr.align ? attr.align : mem->ty->align; - - if (consume(&tok, tok, ":")) { - mem->is_bitfield = true; - mem->bit_width = const_expr(&tok, tok); - } - - cur = cur->next = mem; - } - } - - // If the last element is an array of incomplete type, it's - // called a "flexible array member". It should behave as if - // if were a zero-sized array. - if (cur != &head && cur->ty->kind == TY_ARRAY && cur->ty->array_len < 0) { - cur->ty = array_of(cur->ty->base, 0); - ty->is_flexible = true; - } - - *rest = tok->next; - ty->members = head.next; -} - -// attribute = ("__attribute__" "(" "(" "packed" ")" ")")* -static Token *attribute_list(Token *tok, Type *ty) { - while (consume(&tok, tok, "__attribute__")) { - tok = skip(tok, "("); - tok = skip(tok, "("); - - bool first = true; - - while (!consume(&tok, tok, ")")) { - if (!first) - tok = skip(tok, ","); - first = false; - - if (consume(&tok, tok, "packed")) { - ty->is_packed = true; - continue; - } - - if (consume(&tok, tok, "aligned")) { - tok = skip(tok, "("); - ty->align = const_expr(&tok, tok); - tok = skip(tok, ")"); - continue; - } - - error_tok(tok, "unknown attribute"); - } - - tok = skip(tok, ")"); - } - - return tok; -} - -// struct-union-decl = attribute? ident? ("{" struct-members)? -static Type *struct_union_decl(Token **rest, Token *tok) { - Type *ty = struct_type(); - tok = attribute_list(tok, ty); - - // Read a tag. - Token *tag = NULL; - if (tok->kind == TK_IDENT) { - tag = tok; - tok = tok->next; - } - - if (tag && !equal(tok, "{")) { - *rest = tok; - - Type *ty2 = find_tag(tag); - if (ty2) - return ty2; - - ty->size = -1; - push_tag_scope(tag, ty); - return ty; - } - - tok = skip(tok, "{"); - - // Construct a struct object. - struct_members(&tok, tok, ty); - *rest = attribute_list(tok, ty); - - if (tag) { - // If this is a redefinition, overwrite a previous type. - // Otherwise, register the struct type. - Type *ty2 = hashmap_get2(&scope->tags, tag->loc, tag->len); - if (ty2) { - *ty2 = *ty; - return ty2; - } - - push_tag_scope(tag, ty); - } - - return ty; -} - -// struct-decl = struct-union-decl -static Type *struct_decl(Token **rest, Token *tok) { - Type *ty = struct_union_decl(rest, tok); - ty->kind = TY_STRUCT; - - if (ty->size < 0) - return ty; - - // Assign offsets within the struct to members. - int bits = 0; - - for (Member *mem = ty->members; mem; mem = mem->next) { - if (mem->is_bitfield && mem->bit_width == 0) { - // Zero-width anonymous bitfield has a special meaning. - // It affects only alignment. - bits = align_to(bits, mem->ty->size * 8); - } else if (mem->is_bitfield) { - int sz = mem->ty->size; - if (bits / (sz * 8) != (bits + mem->bit_width - 1) / (sz * 8)) - bits = align_to(bits, sz * 8); - - mem->offset = align_down(bits / 8, sz); - mem->bit_offset = bits % (sz * 8); - bits += mem->bit_width; - } else { - if (!ty->is_packed) - bits = align_to(bits, mem->align * 8); - mem->offset = bits / 8; - bits += mem->ty->size * 8; - } - - if (!ty->is_packed && ty->align < mem->align) - ty->align = mem->align; - } - - ty->size = align_to(bits, ty->align * 8) / 8; - return ty; -} - -// union-decl = struct-union-decl -static Type *union_decl(Token **rest, Token *tok) { - Type *ty = struct_union_decl(rest, tok); - ty->kind = TY_UNION; - - if (ty->size < 0) - return ty; - - // If union, we don't have to assign offsets because they - // are already initialized to zero. We need to compute the - // alignment and the size though. - for (Member *mem = ty->members; mem; mem = mem->next) { - if (ty->align < mem->align) - ty->align = mem->align; - if (ty->size < mem->ty->size) - ty->size = mem->ty->size; - } - ty->size = align_to(ty->size, ty->align); - return ty; -} - -// Find a struct member by name. -static Member *get_struct_member(Type *ty, Token *tok) { - for (Member *mem = ty->members; mem; mem = mem->next) { - // Anonymous struct member - if ((mem->ty->kind == TY_STRUCT || mem->ty->kind == TY_UNION) && - !mem->name) { - if (get_struct_member(mem->ty, tok)) - return mem; - continue; - } - - // Regular struct member - if (mem->name->len == tok->len && - !strncmp(mem->name->loc, tok->loc, tok->len)) - return mem; - } - return NULL; -} - -// Create a node representing a struct member access, such as foo.bar -// where foo is a struct and bar is a member name. -// -// C has a feature called "anonymous struct" which allows a struct to -// have another unnamed struct as a member like this: -// -// struct { struct { int a; }; int b; } x; -// -// The members of an anonymous struct belong to the outer struct's -// member namespace. Therefore, in the above example, you can access -// member "a" of the anonymous struct as "x.a". -// -// This function takes care of anonymous structs. -static Node *struct_ref(Node *node, Token *tok) { - add_type(node); - if (node->ty->kind != TY_STRUCT && node->ty->kind != TY_UNION) - error_tok(node->tok, "not a struct nor a union"); - - Type *ty = node->ty; - - for (;;) { - Member *mem = get_struct_member(ty, tok); - if (!mem) - error_tok(tok, "no such member"); - node = new_unary(ND_MEMBER, node, tok); - node->member = mem; - if (mem->name) - break; - ty = mem->ty; - } - return node; -} - -// Convert A++ to `(typeof A)((A += 1) - 1)` -static Node *new_inc_dec(Node *node, Token *tok, int addend) { - add_type(node); - return new_cast(new_add(to_assign(new_add(node, new_num(addend, tok), tok)), - new_num(-addend, tok), tok), - node->ty); -} - -// postfix = "(" type-name ")" "{" initializer-list "}" -// = ident "(" func-args ")" postfix-tail* -// | primary postfix-tail* -// -// postfix-tail = "[" expr "]" -// | "(" func-args ")" -// | "." ident -// | "->" ident -// | "++" -// | "--" -static Node *postfix(Token **rest, Token *tok) { - if (equal(tok, "(") && is_typename(tok->next)) { - // Compound literal - Token *start = tok; - Type *ty = typename(&tok, tok->next); - tok = skip(tok, ")"); - - if (scope->next == NULL) { - Obj *var = new_anon_gvar(ty); - gvar_initializer(rest, tok, var); - return new_var_node(var, start); - } - - Obj *var = new_lvar("", ty); - Node *lhs = lvar_initializer(rest, tok, var); - Node *rhs = new_var_node(var, tok); - return new_binary(ND_COMMA, lhs, rhs, start); - } - - Node *node = primary(&tok, tok); - - for (;;) { - if (equal(tok, "(")) { - node = funcall(&tok, tok->next, node); - continue; - } - - if (equal(tok, "[")) { - // x[y] is short for *(x+y) - Token *start = tok; - Node *idx = expr(&tok, tok->next); - tok = skip(tok, "]"); - node = new_unary(ND_DEREF, new_add(node, idx, start), start); - continue; - } - - if (equal(tok, ".")) { - node = struct_ref(node, tok->next); - tok = tok->next->next; - continue; - } - - if (equal(tok, "->")) { - // x->y is short for (*x).y - node = new_unary(ND_DEREF, node, tok); - node = struct_ref(node, tok->next); - tok = tok->next->next; - continue; - } - - if (equal(tok, "++")) { - node = new_inc_dec(node, tok, 1); - tok = tok->next; - continue; - } - - if (equal(tok, "--")) { - node = new_inc_dec(node, tok, -1); - tok = tok->next; - continue; - } - - *rest = tok; - return node; - } -} - -// funcall = (assign ("," assign)*)? ")" -static Node *funcall(Token **rest, Token *tok, Node *fn) { - add_type(fn); - - if (fn->ty->kind != TY_FUNC && - (fn->ty->kind != TY_PTR || fn->ty->base->kind != TY_FUNC)) - error_tok(fn->tok, "not a function"); - - Type *ty = (fn->ty->kind == TY_FUNC) ? fn->ty : fn->ty->base; - Type *param_ty = ty->params; - - Node head = {}; - Node *cur = &head; - - while (!equal(tok, ")")) { - if (cur != &head) - tok = skip(tok, ","); - - Node *arg = assign(&tok, tok); - add_type(arg); - - if (!param_ty && !ty->is_variadic) - error_tok(tok, "too many arguments"); - - if (param_ty) { - if (param_ty->kind != TY_STRUCT && param_ty->kind != TY_UNION) - arg = new_cast(arg, param_ty); - param_ty = param_ty->next; - } else if (arg->ty->kind == TY_FLOAT) { - // If parameter type is omitted (e.g. in "..."), float - // arguments are promoted to double. - arg = new_cast(arg, ty_double); - } - - cur = cur->next = arg; - } - - if (param_ty) - error_tok(tok, "too few arguments"); - - *rest = skip(tok, ")"); - - Node *node = new_unary(ND_FUNCALL, fn, tok); - node->func_ty = ty; - node->ty = ty->return_ty; - node->args = head.next; - - // If a function returns a struct, it is caller's responsibility - // to allocate a space for the return value. - if (node->ty->kind == TY_STRUCT || node->ty->kind == TY_UNION) - node->ret_buffer = new_lvar("", node->ty); - return node; -} - -// generic-selection = "(" assign "," generic-assoc ("," generic-assoc)* ")" -// -// generic-assoc = type-name ":" assign -// | "default" ":" assign -static Node *generic_selection(Token **rest, Token *tok) { - Token *start = tok; - tok = skip(tok, "("); - - Node *ctrl = assign(&tok, tok); - add_type(ctrl); - - Type *t1 = ctrl->ty; - if (t1->kind == TY_FUNC) - t1 = pointer_to(t1); - else if (t1->kind == TY_ARRAY) - t1 = pointer_to(t1->base); - - Node *ret = NULL; - - while (!consume(rest, tok, ")")) { - tok = skip(tok, ","); - - if (equal(tok, "default")) { - tok = skip(tok->next, ":"); - Node *node = assign(&tok, tok); - if (!ret) - ret = node; - continue; - } - - Type *t2 = typename(&tok, tok); - tok = skip(tok, ":"); - Node *node = assign(&tok, tok); - if (is_compatible(t1, t2)) - ret = node; - } - - if (!ret) - error_tok(start, "controlling expression type not compatible with" - " any generic association type"); - return ret; -} - -// primary = "(" "{" stmt+ "}" ")" -// | "(" expr ")" -// | "sizeof" "(" type-name ")" -// | "sizeof" unary -// | "_Alignof" "(" type-name ")" -// | "_Alignof" unary -// | "_Generic" generic-selection -// | "__builtin_types_compatible_p" "(" type-name, type-name, ")" -// | "__builtin_reg_class" "(" type-name ")" -// | ident -// | str -// | num -static Node *primary(Token **rest, Token *tok) { - Token *start = tok; - - if (equal(tok, "(") && equal(tok->next, "{")) { - // This is a GNU statement expresssion. - Node *node = new_node(ND_STMT_EXPR, tok); - node->body = compound_stmt(&tok, tok->next->next)->body; - *rest = skip(tok, ")"); - return node; - } - - if (equal(tok, "(")) { - Node *node = expr(&tok, tok->next); - *rest = skip(tok, ")"); - return node; - } - - if (equal(tok, "sizeof") && equal(tok->next, "(") && is_typename(tok->next->next)) { - Type *ty = typename(&tok, tok->next->next); - *rest = skip(tok, ")"); - - if (ty->kind == TY_VLA) { - if (ty->vla_size) - return new_var_node(ty->vla_size, tok); - - Node *lhs = compute_vla_size(ty, tok); - Node *rhs = new_var_node(ty->vla_size, tok); - return new_binary(ND_COMMA, lhs, rhs, tok); - } - - return new_ulong(ty->size, start); - } - - if (equal(tok, "sizeof")) { - Node *node = unary(rest, tok->next); - add_type(node); - if (node->ty->kind == TY_VLA) - return new_var_node(node->ty->vla_size, tok); - return new_ulong(node->ty->size, tok); - } - - if (equal(tok, "_Alignof") && equal(tok->next, "(") && is_typename(tok->next->next)) { - Type *ty = typename(&tok, tok->next->next); - *rest = skip(tok, ")"); - return new_ulong(ty->align, tok); - } - - if (equal(tok, "_Alignof")) { - Node *node = unary(rest, tok->next); - add_type(node); - return new_ulong(node->ty->align, tok); - } - - if (equal(tok, "_Generic")) - return generic_selection(rest, tok->next); - - if (equal(tok, "__builtin_types_compatible_p")) { - tok = skip(tok->next, "("); - Type *t1 = typename(&tok, tok); - tok = skip(tok, ","); - Type *t2 = typename(&tok, tok); - *rest = skip(tok, ")"); - return new_num(is_compatible(t1, t2), start); - } - - if (equal(tok, "__builtin_reg_class")) { - tok = skip(tok->next, "("); - Type *ty = typename(&tok, tok); - *rest = skip(tok, ")"); - - if (is_integer(ty) || ty->kind == TY_PTR) - return new_num(0, start); - if (is_flonum(ty)) - return new_num(1, start); - return new_num(2, start); - } - - if (equal(tok, "__builtin_compare_and_swap")) { - Node *node = new_node(ND_CAS, tok); - tok = skip(tok->next, "("); - node->cas_addr = assign(&tok, tok); - tok = skip(tok, ","); - node->cas_old = assign(&tok, tok); - tok = skip(tok, ","); - node->cas_new = assign(&tok, tok); - *rest = skip(tok, ")"); - return node; - } - - if (equal(tok, "__builtin_atomic_exchange")) { - Node *node = new_node(ND_EXCH, tok); - tok = skip(tok->next, "("); - node->lhs = assign(&tok, tok); - tok = skip(tok, ","); - node->rhs = assign(&tok, tok); - *rest = skip(tok, ")"); - return node; - } - - if (tok->kind == TK_IDENT) { - // Variable or enum constant - VarScope *sc = find_var(tok); - *rest = tok->next; - - // For "static inline" function - if (sc && sc->var && sc->var->is_function) { - if (current_fn) - strarray_push(¤t_fn->refs, sc->var->name); - else - sc->var->is_root = true; - } - - if (sc) { - if (sc->var) - return new_var_node(sc->var, tok); - if (sc->enum_ty) - return new_num(sc->enum_val, tok); - } - - if (equal(tok->next, "(")) - error_tok(tok, "implicit declaration of a function"); - error_tok(tok, "undefined variable"); - } - - if (tok->kind == TK_STR) { - Obj *var = new_string_literal(tok->str, tok->ty); - *rest = tok->next; - return new_var_node(var, tok); - } - - if (tok->kind == TK_NUM) { - Node *node; - if (is_flonum(tok->ty)) { - node = new_node(ND_NUM, tok); - node->fval = tok->fval; - } else { - node = new_num(tok->val, tok); - } - - node->ty = tok->ty; - *rest = tok->next; - return node; - } - - error_tok(tok, "expected an expression"); -} - -static Token *parse_typedef(Token *tok, Type *basety) { - bool first = true; - - while (!consume(&tok, tok, ";")) { - if (!first) - tok = skip(tok, ","); - first = false; - - Type *ty = declarator(&tok, tok, basety); - if (!ty->name) - error_tok(ty->name_pos, "typedef name omitted"); - push_scope(get_ident(ty->name))->type_def = ty; - } - return tok; -} - -static void create_param_lvars(Type *param) { - if (param) { - create_param_lvars(param->next); - if (!param->name) - error_tok(param->name_pos, "parameter name omitted"); - new_lvar(get_ident(param->name), param); - } -} - -// This function matches gotos or labels-as-values with labels. -// -// We cannot resolve gotos as we parse a function because gotos -// can refer a label that appears later in the function. -// So, we need to do this after we parse the entire function. -static void resolve_goto_labels(void) { - for (Node *x = gotos; x; x = x->goto_next) { - for (Node *y = labels; y; y = y->goto_next) { - if (!strcmp(x->label, y->label)) { - x->unique_label = y->unique_label; - break; - } - } - - if (x->unique_label == NULL) - error_tok(x->tok->next, "use of undeclared label"); - } - - gotos = labels = NULL; -} - -static Obj *find_func(char *name) { - Scope *sc = scope; - while (sc->next) - sc = sc->next; - - VarScope *sc2 = hashmap_get(&sc->vars, name); - if (sc2 && sc2->var && sc2->var->is_function) - return sc2->var; - return NULL; -} - -static void mark_live(Obj *var) { - if (!var->is_function || var->is_live) - return; - var->is_live = true; - - for (int i = 0; i < var->refs.len; i++) { - Obj *fn = find_func(var->refs.data[i]); - if (fn) - mark_live(fn); - } -} - -static Token *function(Token *tok, Type *basety, VarAttr *attr) { - Type *ty = declarator(&tok, tok, basety); - if (!ty->name) - error_tok(ty->name_pos, "function name omitted"); - char *name_str = get_ident(ty->name); - - Obj *fn = find_func(name_str); - if (fn) { - // Redeclaration - if (!fn->is_function) - error_tok(tok, "redeclared as a different kind of symbol"); - if (fn->is_definition && equal(tok, "{")) - error_tok(tok, "redefinition of %s", name_str); - if (!fn->is_static && attr->is_static) - error_tok(tok, "static declaration follows a non-static declaration"); - fn->is_definition = fn->is_definition || equal(tok, "{"); - } else { - fn = new_gvar(name_str, ty); - fn->is_function = true; - fn->is_definition = equal(tok, "{"); - fn->is_static = attr->is_static || (attr->is_inline && !attr->is_extern); - fn->is_inline = attr->is_inline; - } - - fn->is_root = !(fn->is_static && fn->is_inline); - - if (consume(&tok, tok, ";")) - return tok; - - current_fn = fn; - locals = NULL; - enter_scope(); - create_param_lvars(ty->params); - - // A buffer for a struct/union return value is passed - // as the hidden first parameter. - Type *rty = ty->return_ty; - if ((rty->kind == TY_STRUCT || rty->kind == TY_UNION) && rty->size > 16) - new_lvar("", pointer_to(rty)); - - fn->params = locals; - - if (ty->is_variadic) - fn->va_area = new_lvar("__va_area__", array_of(ty_char, 136)); - fn->alloca_bottom = new_lvar("__alloca_size__", pointer_to(ty_char)); - - tok = skip(tok, "{"); - - // [https://www.sigbus.info/n1570#6.4.2.2p1] "__func__" is - // automatically defined as a local variable containing the - // current function name. - push_scope("__func__")->var = - new_string_literal(fn->name, array_of(ty_char, strlen(fn->name) + 1)); - - // [GNU] __FUNCTION__ is yet another name of __func__. - push_scope("__FUNCTION__")->var = - new_string_literal(fn->name, array_of(ty_char, strlen(fn->name) + 1)); - - fn->body = compound_stmt(&tok, tok); - fn->locals = locals; - leave_scope(); - resolve_goto_labels(); - return tok; -} - -static Token *global_variable(Token *tok, Type *basety, VarAttr *attr) { - bool first = true; - - while (!consume(&tok, tok, ";")) { - if (!first) - tok = skip(tok, ","); - first = false; - - Type *ty = declarator(&tok, tok, basety); - if (!ty->name) - error_tok(ty->name_pos, "variable name omitted"); - - Obj *var = new_gvar(get_ident(ty->name), ty); - var->is_definition = !attr->is_extern; - var->is_static = attr->is_static; - var->is_tls = attr->is_tls; - if (attr->align) - var->align = attr->align; - - if (equal(tok, "=")) - gvar_initializer(&tok, tok->next, var); - else if (!attr->is_extern && !attr->is_tls) - var->is_tentative = true; - } - return tok; -} - -// Lookahead tokens and returns true if a given token is a start -// of a function definition or declaration. -static bool is_function(Token *tok) { - if (equal(tok, ";")) - return false; - - Type dummy = {}; - Type *ty = declarator(&tok, tok, &dummy); - return ty->kind == TY_FUNC; -} - -// Remove redundant tentative definitions. -static void scan_globals(void) { - Obj head; - Obj *cur = &head; - - for (Obj *var = globals; var; var = var->next) { - if (!var->is_tentative) { - cur = cur->next = var; - continue; - } - - // Find another definition of the same identifier. - Obj *var2 = globals; - for (; var2; var2 = var2->next) - if (var != var2 && var2->is_definition && !strcmp(var->name, var2->name)) - break; - - // If there's another definition, the tentative definition - // is redundant - if (!var2) - cur = cur->next = var; - } - - cur->next = NULL; - globals = head.next; -} - -static void declare_builtin_functions(void) { - Type *ty = func_type(pointer_to(ty_void)); - ty->params = copy_type(ty_int); - builtin_alloca = new_gvar("alloca", ty); - builtin_alloca->is_definition = false; -} - -// program = (typedef | function-definition | global-variable)* -Obj *parse(Token *tok) { - declare_builtin_functions(); - globals = NULL; - - while (tok->kind != TK_EOF) { - VarAttr attr = {}; - Type *basety = declspec(&tok, tok, &attr); - - // Typedef - if (attr.is_typedef) { - tok = parse_typedef(tok, basety); - continue; - } - - // Function - if (is_function(tok)) { - tok = function(tok, basety, &attr); - continue; - } - - // Global variable - tok = global_variable(tok, basety, &attr); - } - - for (Obj *var = globals; var; var = var->next) - if (var->is_root) - mark_live(var); - - // Remove redundant tentative definitions. - scan_globals(); - return globals; -} -- cgit v1.2.3