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cpp.c
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cpp.c
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#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include "8cc.h"
static Dict *macros = &EMPTY_DICT;
static List *cond_incl_stack = &EMPTY_LIST;
static List *std_include_path;
static Token *cpp_token_zero = &(Token){ .type = TTYPE_NUMBER, .sval = "0" };
static Token *cpp_token_one = &(Token){ .type = TTYPE_NUMBER, .sval = "1" };
typedef enum { IN_THEN, IN_ELSE } CondInclCtx;
typedef struct {
CondInclCtx ctx;
bool wastrue;
} CondIncl;
typedef enum { MACRO_OBJ, MACRO_FUNC } MacroType;
typedef struct {
MacroType type;
int nargs;
List *body;
bool is_varg;
} Macro;
static Macro *make_obj_macro(List *body);
static Token *read_token_int(bool return_at_eol);
static Token *read_expand(void);
static void eval(char *buf) {
FILE *fp = fmemopen(buf, strlen(buf), "r");
set_input_file("(eval)", fp);
List *toplevels = read_toplevels();
for (Iter *i = list_iter(toplevels); !iter_end(i);)
emit_toplevel(iter_next(i));
set_input_file("(stdin)", stdin);
}
static __attribute__((constructor)) void init(void) {
std_include_path = make_list();
list_push(std_include_path, "/usr/local/include");
list_push(std_include_path, "/usr/include/x86_64-linux-gnu");
list_push(std_include_path, "/usr/include/linux");
list_push(std_include_path, "/usr/lib/gcc/x86_64-linux-gnu/7/include");
list_push(std_include_path, "/usr/include");
list_push(std_include_path, ".");
dict_put(macros, "__x86_64__", make_obj_macro(make_list1(cpp_token_one)));
dict_put(macros, "__8cc__", make_obj_macro(make_list1(cpp_token_one)));
dict_put(macros, "__STDC__", make_obj_macro(make_list1(cpp_token_one)));
eval("typedef int __builtin_va_list[1];");
eval("typedef int size_t;");
}
static CondIncl *make_cond_incl(CondInclCtx ctx, bool wastrue) {
CondIncl *r = malloc(sizeof(CondIncl));
r->ctx = ctx;
r->wastrue = wastrue;
return r;
}
static Macro *make_obj_macro(List *body) {
Macro *r = malloc(sizeof(Macro));
r->type = MACRO_OBJ;
r->body = body;
r->is_varg = false;
return r;
}
static Macro *make_func_macro(List *body, int nargs, bool is_varg) {
Macro *r = malloc(sizeof(Macro));
r->type = MACRO_FUNC;
r->nargs = nargs;
r->body = body;
r->is_varg = is_varg;
return r;
}
static Token *make_macro_token(int position) {
Token *r = malloc(sizeof(Token));
r->type = TTYPE_MACRO_PARAM;
r->hideset = make_dict(NULL);
r->position = position;
r->space = false;
r->bol = false;
return r;
}
static Token *copy_token(Token *tok) {
Token *r = malloc(sizeof(Token));
memcpy(r, tok, sizeof(Token));
return r;
}
static void expect(char punct) {
Token *tok = read_cpp_token();
if (!tok || !is_punct(tok, punct))
error("%c expected, but got %s", punct, t2s(tok));
}
static Token *read_ident(void) {
Token *r = read_cpp_token();
if (r->type != TTYPE_IDENT)
error("identifier expected, but got %s", t2s(r));
return r;
}
static void expect_newline(void) {
Token *tok = read_cpp_token();
if (!tok || tok->type != TTYPE_NEWLINE)
error("Newline expected, but got %s", t2s(tok));
}
static List *read_args_int(Macro *macro) {
Token *tok = read_cpp_token();
if (!tok || !is_punct(tok, '(')) {
unget_token(tok);
return NULL;
}
List *r = make_list();
List *arg = make_list();
int depth = 0;
for (;;) {
tok = read_cpp_token();
if (!tok)
error("unterminated macro argument list");
if (tok->type == TTYPE_NEWLINE)
continue;
if (is_punct(tok, '(')) {
depth++;
} else if (depth) {
if (is_punct(tok, ')'))
depth--;
list_push(arg, tok);
continue;
}
if (is_punct(tok, ')')) {
unget_token(tok);
list_push(r, arg);
return r;
}
bool in_threedots = macro->is_varg && list_len(r) + 1 == macro->nargs;
if (is_punct(tok, ',') && !in_threedots) {
list_push(r, arg);
arg = make_list();
continue;
}
list_push(arg, tok);
}
}
static List *read_args(Macro *macro) {
List *args = read_args_int(macro);
if (!args) return NULL;
if ((macro->is_varg && list_len(args) < macro->nargs) ||
(!macro->is_varg && list_len(args) != macro->nargs))
error("Macro argument number does not match");
return args;
}
static Dict *dict_union(Dict *a, Dict *b) {
Dict *r = make_dict(NULL);
for (Iter *i = list_iter(dict_keys(a)); !iter_end(i);) {
char *key = iter_next(i);
dict_put(r, key, dict_get(a, key));
}
for (Iter *i = list_iter(dict_keys(b)); !iter_end(i);) {
char *key = iter_next(i);
dict_put(r, key, dict_get(b, key));
}
return r;
}
static Dict *dict_intersection(Dict *a, Dict *b) {
Dict *r = make_dict(NULL);
for (Iter *i = list_iter(dict_keys(a)); !iter_end(i);) {
char *key = iter_next(i);
if (dict_get(b, key))
dict_put(r, key, (void *)1);
}
return r;
}
static Dict *dict_append(Dict *dict, char *s) {
Dict *r = make_dict(dict);
dict_put(r, s, (void *)1);
return r;
}
static List *add_hide_set(List *tokens, Dict *hideset) {
List *r = make_list();
for (Iter *i = list_iter(tokens); !iter_end(i);) {
Token *t = copy_token(iter_next(i));
t->hideset = dict_union(t->hideset, hideset);
list_push(r, t);
}
return r;
}
static void paste(String *s, Token *tok) {
switch (tok->type) {
case TTYPE_IDENT:
case TTYPE_NUMBER:
string_appendf(s, "%s", tok->sval);
return;
case TTYPE_PUNCT:
string_appendf(s, "%c", tok->c);
return;
default:
error("can't paste: %s", t2s(tok));
}
}
static Token *glue_tokens(Token *t0, Token *t1) {
String *s = make_string();
paste(s, t0);
paste(s, t1);
Token *r = copy_token(t0);
r->type = isdigit(get_cstring(s)[0]) ? TTYPE_NUMBER : TTYPE_IDENT;
r->sval = get_cstring(s);
return r;
}
static void glue_push(List *tokens, Token *tok) {
assert(list_len(tokens) > 0);
Token *last = list_pop(tokens);
list_push(tokens, glue_tokens(last, tok));
}
static char *join_tokens(List *args) {
String *s = make_string();
for (Iter *i = list_iter(args); !iter_end(i);) {
Token *tok = iter_next(i);
if (string_len(s) && tok->space)
string_appendf(s, " ");
switch (tok->type) {
case TTYPE_IDENT:
case TTYPE_NUMBER:
string_appendf(s, "%s", tok->sval);
break;
case TTYPE_PUNCT:
string_appendf(s, "%c", tok->c);
break;
case TTYPE_CHAR:
string_appendf(s, "%s", quote_char(tok->c));
break;
case TTYPE_STRING:
string_appendf(s, "\"%s\"", tok->sval);
break;
default:
error("internal error");
}
}
return get_cstring(s);
}
static Token *stringize(List *args) {
Token *r = malloc(sizeof(Token));
r->type = TTYPE_STRING;
r->sval = join_tokens(args);
return r;
}
static List *expand_all(List *tokens) {
List *r = make_list();
List *orig = get_input_buffer();
set_input_buffer(tokens);
Token *tok;
while ((tok = read_expand()) != NULL)
list_push(r, tok);
set_input_buffer(orig);
return r;
}
static List *subst(Macro *macro, List *args, Dict *hideset) {
List *r = make_list();
for (int i = 0; i < list_len(macro->body); i++) {
bool islast = (i == list_len(macro->body) - 1);
Token *t0 = list_get(macro->body, i);
Token *t1 = islast ? NULL : list_get(macro->body, i + 1);
bool t0_param = (t0->type == TTYPE_MACRO_PARAM);
bool t1_param = (!islast && t1->type == TTYPE_MACRO_PARAM);
if (is_punct(t0, '#') && t1_param) {
list_push(r, stringize(list_get(args, t1->position)));
i++;
continue;
}
if (is_ident(t0, "##") && t1_param) {
List *arg = list_get(args, t1->position);
if (list_len(arg) > 0) {
glue_push(r, list_head(arg));
List *tmp = list_copy(arg);
list_shift(tmp);
list_append(r, expand_all(tmp));
}
i++;
continue;
}
if (is_ident(t0, "##") && !islast) {
hideset = t1->hideset;
glue_push(r, t1);
i++;
continue;
}
if (t0_param && !islast && is_ident(t1, "##")) {
hideset = t1->hideset;
List *arg = list_get(args, t0->position);
if (list_len(arg) == 0)
i++;
else
list_append(r, arg);
continue;
}
if (t0_param) {
List *arg = list_get(args, t0->position);
list_append(r, expand_all(arg));
continue;
}
list_push(r, t0);
}
return add_hide_set(r, hideset);
}
static void unget_all(List *tokens) {
for (Iter *i = list_iter(list_reverse(tokens)); !iter_end(i);)
unget_token(iter_next(i));
}
static Token *read_expand(void) {
Token *tok = read_cpp_token();
if (!tok) return NULL;
if (tok->type == TTYPE_NEWLINE)
return read_expand();
if (tok->type != TTYPE_IDENT)
return tok;
char *name = tok->sval;
Macro *macro = dict_get(macros, name);
if (!macro || dict_get(tok->hideset, name))
return tok;
switch (macro->type) {
case MACRO_OBJ: {
Dict *hideset = dict_append(tok->hideset, name);
List *tokens = subst(macro, make_list(), hideset);
unget_all(tokens);
return read_expand();
}
case MACRO_FUNC: {
List *args = read_args(macro);
Token *rparen = read_cpp_token();
assert(is_punct(rparen, ')'));
Dict *hideset = dict_append(dict_intersection(tok->hideset, rparen->hideset), name);
List *tokens = subst(macro, args, hideset);
unget_all(tokens);
return read_expand();
}
default:
error("internal error");
}
}
static bool read_funclike_macro_args(Dict *param) {
int pos = 0;
for (;;) {
Token *tok = read_cpp_token();
if (is_punct(tok, ')'))
return false;
if (pos) {
if (!is_punct(tok, ','))
error("',' expected, but got '%s'", t2s(tok));
tok = read_cpp_token();
}
if (!tok || tok->type == TTYPE_NEWLINE)
error("missing ')' in macro parameter list");
if (is_ident(tok, "...")) {
dict_put(param, "__VA_ARGS__", make_macro_token(pos++));
expect(')');
return true;
}
if (tok->type != TTYPE_IDENT)
error("identifier expected, but got '%s'", t2s(tok));
dict_put(param, tok->sval, make_macro_token(pos++));
}
}
static List *read_funclike_macro_body(Dict *param) {
List *r = make_list();
for (;;) {
Token *tok = read_cpp_token();
if (!tok || tok->type == TTYPE_NEWLINE)
return r;
if (tok->type == TTYPE_IDENT) {
Token *subst = dict_get(param, tok->sval);
if (subst) {
list_push(r, subst);
continue;
}
}
list_push(r, tok);
}
return r;
}
static void read_funclike_macro(char *name) {
Dict *param = make_dict(NULL);
bool varg = read_funclike_macro_args(param);
List *body = read_funclike_macro_body(param);
Macro *macro = make_func_macro(body, list_len(dict_keys(param)), varg);
dict_put(macros, name, macro);
}
static void read_obj_macro(char *name) {
List *body = make_list();
for (;;) {
Token *tok = read_cpp_token();
if (!tok || tok->type == TTYPE_NEWLINE)
break;
list_push(body, tok);
}
dict_put(macros, name, make_obj_macro(body));
}
static void read_define(void) {
Token *name = read_ident();
Token *tok = read_cpp_token();
if (tok && is_punct(tok, '(') && !tok->space) {
read_funclike_macro(name->sval);
return;
}
unget_token(tok);
read_obj_macro(name->sval);
}
static void read_undef(void) {
Token *name = read_ident();
expect_newline();
dict_remove(macros, name->sval);
}
static Token *read_defined_operator(void) {
Token *tok = read_cpp_token();
if (is_punct(tok, '(')) {
tok = read_cpp_token();
expect(')');
}
if (tok->type != TTYPE_IDENT)
error("Identifier expected, but got %s", t2s(tok));
return dict_get(macros, tok->sval) ?
cpp_token_one : cpp_token_zero;
}
static List *read_intexpr_line(void) {
List *r = make_list();
for (;;) {
Token *tok = read_token_int(true);
if (!tok) return r;
if (is_ident(tok, "defined"))
list_push(r, read_defined_operator());
else if (tok->type == TTYPE_IDENT)
list_push(r, cpp_token_one);
else
list_push(r, tok);
}
}
static bool read_constexpr(void) {
List *orig = get_input_buffer();
set_input_buffer(read_intexpr_line());
Ast *expr = read_expr();
List *buf = get_input_buffer();
if (list_len(buf) > 0)
error("Stray token: %s", t2s(list_shift(buf)));
set_input_buffer(orig);
return eval_intexpr(expr);
}
static void read_if_generic(bool cond) {
list_push(cond_incl_stack, make_cond_incl(IN_THEN, cond));
if (!cond)
skip_cond_incl();
}
static void read_if(void) {
read_if_generic(read_constexpr());
}
static void read_ifdef_generic(bool is_ifdef) {
Token *tok = read_cpp_token();
if (!tok || tok->type != TTYPE_IDENT)
error("identifier expected, but got %s", t2s(tok));
bool cond = dict_get(macros, tok->sval);
expect_newline();
read_if_generic(is_ifdef ? cond : !cond);
}
static void read_ifdef(void) {
read_ifdef_generic(true);
}
static void read_ifndef(void) {
read_ifdef_generic(false);
}
static void read_else(void) {
if (list_len(cond_incl_stack) == 0)
error("stray #else");
CondIncl *ci = list_tail(cond_incl_stack);
if (ci->ctx == IN_ELSE)
error("#else appears in #else");
expect_newline();
if (ci->wastrue)
skip_cond_incl();
}
static void read_elif(void) {
if (list_len(cond_incl_stack) == 0)
error("stray #elif");
CondIncl *ci = list_tail(cond_incl_stack);
if (ci->ctx == IN_ELSE)
error("#elif after #else");
if (ci->wastrue)
skip_cond_incl();
else {
bool cond = read_constexpr();
ci->wastrue = cond;
if (!cond)
skip_cond_incl();
}
}
static void read_endif(void) {
if (list_len(cond_incl_stack) == 0)
error("stray #endif");
list_pop(cond_incl_stack);
expect_newline();
}
static void read_cpp_header_name(char **name, bool *std) {
if (!get_input_buffer()) {
if (read_header_file_name(name, std))
return;
}
}
static char *construct_path(char *path1, char *path2) {
if (path1[0] == '\0')
return path2;
return format("%s/%s", path1, path2);
}
static void read_include(void) {
char *name;
bool std;
read_cpp_header_name(&name, &std);
expect_newline();
List *paths = std ? std_include_path : make_list1("");
for (Iter *i = list_iter(paths); !iter_end(i);) {
char *path = construct_path(iter_next(i), name);
FILE *fp = fopen(path, "r");
if (fp) {
push_input_file(path, fp);
return;
}
}
error("Cannot find header file: %s", name);
}
static char *macro_to_string(char *name, Macro *m) {
String *s = make_string();
if (m->type == MACRO_OBJ)
string_appendf(s, "%s ->", name, m->nargs);
else
string_appendf(s, "%s(%d) ->", name, m->nargs);
if (!m->body) return get_cstring(s);
for (Iter *i = list_iter(m->body); !iter_end(i);)
string_appendf(s, " %s", t2s(iter_next(i)));
return get_cstring(s);
}
static void read_print(void) {
Token *tok = read_cpp_token();
expect_newline();
fprintf(stderr, "#print %s: ", input_position());
if (tok->type == TTYPE_IDENT) {
Macro *m = dict_get(macros, tok->sval);
if (m) {
fprintf(stderr, "%s\n", macro_to_string(tok->sval, m));
return;
}
}
fprintf(stderr, "%s\n", t2s(tok));
}
static void read_directive(void) {
Token *tok = read_cpp_token();
if (is_ident(tok, "define")) read_define();
else if (is_ident(tok, "undef")) read_undef();
else if (is_ident(tok, "if")) read_if();
else if (is_ident(tok, "ifdef")) read_ifdef();
else if (is_ident(tok, "ifndef")) read_ifndef();
else if (is_ident(tok, "else")) read_else();
else if (is_ident(tok, "elif")) read_elif();
else if (is_ident(tok, "endif")) read_endif();
else if (is_ident(tok, "include")) read_include();
else if (is_ident(tok, "print")) read_print();
else
error("unsupported preprocessor directive: %s", t2s(tok));
}
void unget_token(Token *tok) {
unget_cpp_token(tok);
}
Token *peek_token(void) {
Token *r = read_token();
unget_token(r);
return r;
}
static Token *read_token_int(bool return_at_eol) {
for (;;) {
Token *tok = read_cpp_token();
if (!tok)
return NULL;
if (tok && tok->type == TTYPE_NEWLINE) {
if (return_at_eol)
return NULL;
continue;
}
if (tok->bol && is_punct(tok, '#')) {
read_directive();
continue;
}
unget_token(tok);
Token *r = read_expand();
if (r && r->bol && is_punct(r, '#') && dict_empty(r->hideset)) {
read_directive();
continue;
}
return r;
}
}
Token *read_token(void) {
Token *r = read_token_int(false);
if (!r) return NULL;
assert(r->type != TTYPE_NEWLINE);
assert(r->type != TTYPE_SPACE);
assert(r->type != TTYPE_MACRO_PARAM);
return r;
}