summaryrefslogtreecommitdiffhomepage
path: root/src/3p/chibicc/parse.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/3p/chibicc/parse.c')
-rw-r--r--src/3p/chibicc/parse.c3368
1 files changed, 0 insertions, 3368 deletions
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(&current_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;
-}
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-29 05:49:01 +0000