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b8108acb2e
RVBTCC/boot.c
Yaossg b8108acb2e primary function call
2024-11-20 23:44:42 +08:00

1503 lines
38 KiB
C
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#include "boot-lib.h"
// lexer
int is_digit(int ch) {
return '0' <= ch && ch <= '9';
}
int is_id_start(int ch) {
return 'a' <= ch && ch <= 'z' || 'A' <= ch && ch <= 'Z' || ch == '_';
}
int is_id_cont(int ch) {
return is_id_start(ch) || is_digit(ch);
}
int token_state;
int token_type;
int token_data;
const int TOKEN_EOF = 0;
const int TOKEN_SEMICOLON = 1;
const int TOKEN_ADD = 2;
const int TOKEN_MINUS = 3;
const int TOKEN_STAR = 4;
const int TOKEN_DIV = 5;
const int TOKEN_REM = 6;
const int TOKEN_ASSIGN = 7;
const int TOKEN_COMMA = 8;
const int TOKEN_DOT = 9;
const int TOKEN_LSHIFT = 10;
const int TOKEN_RSHIFT = 11;
const int TOKEN_AND = 12;
const int TOKEN_OR = 13;
const int TOKEN_XOR = 14;
const int TOKEN_COMPL = 15;
const int TOKEN_NOT = 16;
const int TOKEN_LAND = 17;
const int TOKEN_LOR = 18;
const int TOKEN_ELLIPSIS = 19;
const int TOKEN_INC = 20;
const int TOKEN_DEC = 21;
const int TOKEN_EQ = 40;
const int TOKEN_NE = 41;
const int TOKEN_LT = 42;
const int TOKEN_GT = 43;
const int TOKEN_LE = 44;
const int TOKEN_GE = 45;
const int TOKEN_PAREN_LEFT = 50;
const int TOKEN_PAREN_RIGHT = 51;
const int TOKEN_BRACKET_LEFT = 52;
const int TOKEN_BRACKET_RIGHT = 53;
const int TOKEN_BRACE_LEFT = 54;
const int TOKEN_BRACE_RIGHT = 55;
const int TOKEN_STRING = 99;
const int TOKEN_NUMBER = 100;
const int TOKEN_ID = 101;
const int TOKEN_IF = 102;
const int TOKEN_ELSE = 103;
const int TOKEN_WHILE = 104;
const int TOKEN_FOR = 105;
const int TOKEN_DO = 106;
const int TOKEN_BREAK = 107;
const int TOKEN_CONTINUE = 108;
const int TOKEN_RETURN = 109;
const int TOKEN_CONST = 127;
const int TOKEN_VOID = 128;
const int TOKEN_INT = 129;
const int TOKEN_CHAR = 130;
const int TYPE_VOID = 0;
const int TYPE_INT = 1;
const int TYPE_CHAR = 2;
const int TYPE_VOID_PTR = 16;
const int TYPE_INT_PTR = 17;
const int TYPE_CHAR_PTR = 18;
const int TYPE_PTR_MASK = 16;
const int TYPE_TOKEN_MASK = 128;
int parse_int(int ch) {
int num = ch - '0';
while (is_digit(ch = getchar())) {
num = num * 10;
num = num + ch - '0';
}
ungetchar(ch);
return num;
}
int get_escaped_char() {
int ch = getchar();
if (ch == 'n') {
ch = '\n';
} else if (ch == 't') {
ch = '\t';
} else if (ch == 'r') {
ch = '\r';
} else if (ch == '0') {
ch = '\0';
} else if (ch == '\\') {
ch = '\\';
} else if (ch == '\'') {
ch = '\'';
} else if (ch == '\"') {
ch = '\"';
} else {
eprintf("unexpected escaped character: %c\n", ch);
exit(1);
}
return ch;
}
int streq(const char* s1, const char* s2) {
while (*s1 && *s2 && *s1 == *s2) {
s1++;
s2++;
}
return *s1 == *s2;
}
char string_table[65536];
int string_offset;
int string_lut[4096];
int string_lut_size;
int parse_string() {
int offset = string_offset;
int ch;
while ((ch = getchar()) != '"') {
if (ch == -1 || ch == '\n') {
eprintf("expecting '\"'\n");
exit(1);
}
if (ch == '\\') {
ch = get_escaped_char();
}
string_table[string_offset++] = ch;
}
string_table[string_offset++] = 0;
string_lut[string_lut_size] = offset;
return string_lut_size++;
}
char id_table[65536];
int id_offset;
int id_lut[4096];
int id_lut_size;
int parse_id(int ch) {
int offset = id_offset;
id_table[id_offset++] = ch;
while (is_id_cont(ch = getchar())) {
id_table[id_offset++] = ch;
}
ungetchar(ch);
id_table[id_offset++] = 0;
id_lut[id_lut_size] = offset;
return id_lut_size++;
}
void rewind_id(int new_data) {
id_offset = id_lut[token_data];
token_data = new_data;
--id_lut_size;
}
void dedup_id() {
int last_id = id_lut_size - 1;
char* latest = id_table + id_lut[last_id];
for (int i = 0; i < last_id; i++) {
char* candidate = id_table + id_lut[i];
if (streq(candidate, latest)) {
rewind_id(i);
return;
}
}
}
void parse_id_like(int ch) {
token_type = TOKEN_ID;
token_data = parse_id(ch);
char* id = id_table + id_lut[token_data];
if (streq(id, "int")) {
token_type = TOKEN_INT;
} else if (streq(id, "if")) {
token_type = TOKEN_IF;
} else if (streq(id, "else")) {
token_type = TOKEN_ELSE;
} else if (streq(id, "while")) {
token_type = TOKEN_WHILE;
} else if (streq(id, "break")) {
token_type = TOKEN_BREAK;
} else if (streq(id, "continue")) {
token_type = TOKEN_CONTINUE;
} else if (streq(id, "return")) {
token_type = TOKEN_RETURN;
} else if (streq(id, "void")) {
token_type = TOKEN_VOID;
} else if (streq(id, "const")) {
token_type = TOKEN_CONST;
} else if (streq(id, "char")) {
token_type = TOKEN_CHAR;
} else if (streq(id, "for")) {
token_type = TOKEN_FOR;
} else if (streq(id, "do")) {
token_type = TOKEN_DO;
}
if (token_type != TOKEN_ID) {
rewind_id(0);
} else {
dedup_id();
}
}
void unget_token() {
token_state = 1;
}
void next_token() {
if (token_state) {
token_state = 0;
return;
}
int ch = getchar();
while (ch == ' ' || ch == '\t' || ch == '\r' || ch == '\n') {
ch = getchar();
}
if (ch == -1) {
token_type = TOKEN_EOF;
} else if (ch == '(') {
token_type = TOKEN_PAREN_LEFT;
} else if (ch == ')') {
token_type = TOKEN_PAREN_RIGHT;
} else if (ch == '[') {
token_type = TOKEN_BRACKET_LEFT;
} else if (ch == ']') {
token_type = TOKEN_BRACKET_RIGHT;
} else if (ch == '{') {
token_type = TOKEN_BRACE_LEFT;
} else if (ch == '}') {
token_type = TOKEN_BRACE_RIGHT;
} else if (ch == '+') {
int ch2 = getchar();
if (ch2 == '+') {
token_type = TOKEN_INC;
} else {
ungetchar(ch2);
token_type = TOKEN_ADD;
}
} else if (ch == '-') {
int ch2 = getchar();
if (ch2 == '-') {
token_type = TOKEN_DEC;
} else {
ungetchar(ch2);
token_type = TOKEN_MINUS;
}
} else if (ch == '*') {
token_type = TOKEN_STAR;
} else if (ch == '/') {
int ch2 = getchar();
if (ch2 == '/') {
do ch = getchar(); while (ch != -1 && ch != '\n');
next_token();
return;
} else if (ch2 == '*') {
while (1) {
ch = getchar();
if (ch == -1) {
eprintf("expecting '*/'\n");
exit(1);
}
if (ch == '*') {
ch = getchar();
if (ch == '/') {
break;
}
}
}
next_token();
return;
} else {
ungetchar(ch2);
token_type = TOKEN_DIV;
}
} else if (ch == '%') {
token_type = TOKEN_REM;
} else if (ch == ';') {
token_type = TOKEN_SEMICOLON;
} else if (ch == ',') {
token_type = TOKEN_COMMA;
} else if (ch == '<') {
int ch2 = getchar();
if (ch2 == '=') {
token_type = TOKEN_LE;
} else if (ch2 == '<') {
token_type = TOKEN_LSHIFT;
} else {
ungetchar(ch2);
token_type = TOKEN_LT;
}
} else if (ch == '>') {
int ch2 = getchar();
if (ch2 == '=') {
token_type = TOKEN_GE;
} else if (ch2 == '>') {
token_type = TOKEN_RSHIFT;
} else {
ungetchar(ch2);
token_type = TOKEN_GT;
}
} else if (ch == '=') {
int ch2 = getchar();
if (ch2 == '=') {
token_type = TOKEN_EQ;
} else {
ungetchar(ch2);
token_type = TOKEN_ASSIGN;
}
} else if (ch == '!') {
int ch2 = getchar();
if (ch2 == '=') {
token_type = TOKEN_NE;
} else {
ungetchar(ch2);
token_type = TOKEN_NOT;
}
} else if (ch == '&') {
int ch2 = getchar();
if (ch2 == '&') {
token_type = TOKEN_LAND;
} else {
ungetchar(ch2);
token_type = TOKEN_AND;
}
} else if (ch == '|') {
int ch2 = getchar();
if (ch2 == '|') {
token_type = TOKEN_LOR;
} else {
ungetchar(ch2);
token_type = TOKEN_OR;
}
} else if (ch == '^') {
token_type = TOKEN_XOR;
} else if (ch == '~') {
token_type = TOKEN_COMPL;
} else if (ch == '\'') {
token_type = TOKEN_NUMBER;
token_data = getchar();
if (token_data == '\\') {
token_data = get_escaped_char();
}
if (getchar() != '\'') {
eprintf("expecting '\n");
exit(1);
}
} else if (ch == '"') {
token_type = TOKEN_STRING;
token_data = parse_string();
} else if (ch == '.') {
int ch2 = getchar();
if (ch2 == '.') {
int ch3 = getchar();
if (ch3 == '.') {
token_type = TOKEN_ELLIPSIS;
} else {
eprintf("unexpected character: %c\n", ch3);
exit(1);
}
} else {
eprintf("unexpected character: %c\n", ch2);
exit(1);
}
} else if (is_digit(ch)) {
token_type = TOKEN_NUMBER;
token_data = parse_int(ch);
} else if (is_id_start(ch)) {
parse_id_like(ch);
} else {
eprintf("unexpected character: %c(%d)\n", ch, ch);
exit(1);
}
eprintf("token: %d\n", token_type);
if (token_type == TOKEN_ID) {
const char* name = id_table + id_lut[token_data];
eprintf(" id: %s\n", name);
} else if (token_type == TOKEN_NUMBER) {
eprintf(" number: %d\n", token_data);
}
}
void expect_token(int expected_type) {
next_token();
if (token_type != expected_type) {
eprintf("unexpected token: %d, should be %d\n", token_type, expected_type);
exit(1);
}
}
void ignore_const() {
if (token_type == TOKEN_CONST) {
next_token();
}
}
int parse_type() {
ignore_const();
if (token_type == TOKEN_INT || token_type == TOKEN_CHAR || token_type == TOKEN_VOID) {
int type = token_type & ~TYPE_TOKEN_MASK;
next_token();
ignore_const();
if (token_type == TOKEN_STAR) {
ignore_const();
return type | TYPE_PTR_MASK;
}
unget_token();
return type;
} else {
return -1;
}
}
// asm
int epilog_label;
int local_table[4096]; // id -> local id
int next_local_id = 2;
int max_local_id = 2;
const int MARKER_TEMP = 0;
const int MARKER_SCALAR = 1;
const int MARKER_ARRAY = 2;
const int MARKER_FUNCTION = 3;
int local_marker[4096];
int global_marker[4096];
int local_type[4096];
int global_type[4096];
int indirection[4096];
void reset_local() {
next_local_id = 2;
max_local_id = 2;
for (int i = 0; i < 4096; ++i) {
local_table[i] = 0;
local_marker[i] = MARKER_TEMP;
local_type[i] = TYPE_VOID;
indirection[i] = 0;
}
}
void reset_temp() {
while (next_local_id > 2 && local_marker[next_local_id - 1] == MARKER_TEMP) {
--next_local_id;
}
}
int next_reg(int type) {
int reg = next_local_id++;
local_type[reg] = type;
indirection[reg] = 0;
if (next_local_id > max_local_id) {
max_local_id = next_local_id;
}
return reg;
}
int declare_local(int id, int type) {
if (local_table[id] != 0) return local_table[id];
int reg = next_reg(type);
local_marker[reg] = MARKER_SCALAR;
return local_table[id] = reg;
}
int declare_local_array(int id, int type, int size) {
if (local_table[id] != 0) return local_table[id];
int reg;
for (int i = 0; i < size; ++i) local_marker[reg = next_reg(type)] = MARKER_ARRAY;
return local_table[id] = reg;
}
void declare_global(int id, int marker, int type) {
global_marker[id] = marker;
global_type[id] = type;
}
int check_itype_immediate(int value) {
return value >= -2048 && value <= 2047;
}
void asm_ld(const char* rd, int imm, const char* rs) {
if (check_itype_immediate(imm)) {
printf(" ld %s, %d(%s)\n", rd, imm, rs);
} else {
printf(" li t0, %d\n", imm);
printf(" add t0, %s, t0\n", rs);
printf(" ld %s, 0(t0)\n", rd);
}
}
void asm_sd(const char* rs1, int imm, const char* rs2) {
if (check_itype_immediate(imm)) {
printf(" sd %s, %d(%s)\n", rs1, imm, rs2);
} else {
printf(" li t0, %d\n", imm);
printf(" add t0, %s, t0\n", rs2);
printf(" sd %s, 0(t0)\n", rs1);
}
}
void asm_addi(const char* rd, const char* rs, int imm) {
if (check_itype_immediate(imm)) {
printf(" addi %s, %s, %d\n", rd, rs, imm);
} else {
printf(" li t0, %d\n", imm);
printf(" add %s, %s, t0\n", rd, rs);
}
}
void load_address(int rd, int id) {
if (id == -1) {
eprintf("void cannot be arithmetically operated\n");
exit(1);
}
int offset = -id * 8 - 8;
if (indirection[id]) {
if (check_itype_immediate(offset)) {
printf(" ld t%d, %d(fp) # indirection\n", rd, offset);
} else {
printf(" li t%d, %d\n", rd, offset);
printf(" add t%d, fp, t%d\n", rd, rd);
printf(" ld t%d, 0(t%d) # indirection\n", rd, rd);
}
} else {
if (check_itype_immediate(offset)) {
printf(" addi t%d, fp, %d\n", rd, offset);
} else {
printf(" li t%d, %d\n", rd, offset);
printf(" add t%d, fp, t%d\n", rd, rd);
}
}
}
void load(int rd, int id) {
load_address(rd, id);
int type = local_type[id];
const char* op = "lw"; // int
if (type == TYPE_CHAR) {
op = "lb";
} else if (type & TYPE_PTR_MASK) {
op = "ld";
}
printf(" %s t%d, 0(t%d) # id: type %d\n", op, rd, rd, type);
}
void store_t0(int id) {
load_address(1, id);
int type = local_type[id];
const char* op = "sw"; // int
if (type == TYPE_CHAR) {
op = "sb";
} else if (type & TYPE_PTR_MASK) {
op = "sd";
}
printf(" %s t0, 0(t1) # id: type %d\n", op, type);
}
int materialize_t0(int type) {
int reg = next_reg(type);
store_t0(reg);
return reg;
}
int dereference(int reg) {
local_type[reg] = local_type[reg] & ~TYPE_PTR_MASK;
indirection[reg] = 1;
return reg;
}
int lookup(int id) {
int local = local_table[id];
if (local) {
if (local_marker[local] == MARKER_ARRAY) {
load_address(0, local);
return materialize_t0(local_type[local] | TYPE_PTR_MASK);
}
return local;
}
const char* name = id_table + id_lut[id];
if (global_marker[id]) {
if (global_marker[id] == MARKER_FUNCTION) {
eprintf("function name must not appear outside function call: %s\n", name);
exit(1);
}
printf(" la t0, %s # id: %d\n", name, id);
int reg = materialize_t0(global_type[id] | TYPE_PTR_MASK);
if (global_marker[id] == MARKER_SCALAR) {
reg = dereference(reg);
}
return reg;
}
eprintf("unresolved identifier: %s\n", name);
exit(1);
}
int next_label_id = 0;
int next_label() {
return next_label_id++;
}
int asm_label(int label) {
printf("L%d:\n", label);
return label;
}
int is_not_reusable(int rs1, int expected_type) {
return indirection[rs1] || local_marker[rs1] != MARKER_TEMP || local_type[rs1] != expected_type;
}
int asm_r(const char* op, int rs1) {
load(0, rs1);
printf(" %s t0, t0\n", op);
int rd = rs1;
if (is_not_reusable(rs1, TYPE_INT)) {
rd = next_reg(TYPE_INT);
}
store_t0(rd);
return rd;
}
int asm_r_arith(const char* op, int rs1) {
if (local_type[rs1] & TYPE_PTR_MASK) {
eprintf("pointer cannot be arithmetically operated by %s\n", op);
exit(1);
}
return asm_r(op, rs1);
}
int asm_rr(const char* op, int rs1, int rs2) {
load(0, rs1);
load(1, rs2);
printf(" %s t0, t0, t1\n", op);
int rd = rs1;
if (is_not_reusable(rd, TYPE_INT)) {
rd = rs2;
if (is_not_reusable(rd, TYPE_INT)) {
rd = next_reg(TYPE_INT);
}
}
store_t0(rd);
return rd;
}
int asm_rr_arith(const char* op, int rs1, int rs2) {
if (local_type[rs1] & TYPE_PTR_MASK || local_type[rs2] & TYPE_PTR_MASK) {
eprintf("pointer cannot be arithmetically operated by %s\n", op);
exit(1);
}
return asm_rr(op, rs1, rs2);
}
int asm_rr_cmp(const char* op, int rs1, int rs2) {
// since NULL is virtually 0, it is considered valid example of a pointer comparing with an integer
return asm_rr(op, rs1, rs2);
}
void asm_beqz(int rs1, int label) {
load(0, rs1);
printf(" beqz t0, L%d\n", label);
}
void asm_bnez(int rs1, int label) {
load(0, rs1);
printf(" bnez t0, L%d\n", label);
}
void asm_j(int label) {
printf(" j L%d\n", label);
}
int break_label_stack[4096];
int cont_label_stack[4096];
int break_label_stack_size;
int cont_label_stack_size;
int asm_get_break_label() {
return break_label_stack[break_label_stack_size - 1];
}
int asm_get_cont_label() {
return cont_label_stack[cont_label_stack_size - 1];
}
void asm_push_label(int break_label, int cont_label) {
break_label_stack[break_label_stack_size++] = break_label;
cont_label_stack[cont_label_stack_size++] = cont_label;
}
void asm_pop_label() {
--break_label_stack_size;
--cont_label_stack_size;
}
int step_of(int type) {
if (type == TYPE_INT_PTR) {
return 4;
}
return 1;
}
void asm_shift_t0(const char* op, int type) {
if (type == TYPE_INT_PTR) {
printf(" %s t0, t0, 2\n", op);
}
}
int asm_add(int lhs, int rhs) {
int type1 = local_type[lhs] & TYPE_PTR_MASK;
int type2 = local_type[rhs] & TYPE_PTR_MASK;
if (type1 != type2) {
int ptr;
int idx;
if (type1) {
ptr = lhs;
idx = rhs;
} else {
ptr = rhs;
idx = lhs;
}
int ptr_type = local_type[ptr];
if (ptr_type == TYPE_VOID_PTR) {
eprintf("void pointer cannot be arithmetically operated\n");
exit(1);
}
load(0, idx);
load(1, ptr);
asm_shift_t0("slli", ptr_type);
printf(" add t0, t0, t1\n");
return materialize_t0(ptr_type);
}
if (type1 && type2) {
eprintf("operands of addition cannot be both pointers\n");
exit(1);
}
return asm_rr("add", lhs, rhs);
}
int asm_sub(int lhs, int rhs) {
int lhs_type = local_type[lhs];
int rhs_type = local_type[rhs];
int type1 = lhs_type & TYPE_PTR_MASK;
int type2 = rhs_type & TYPE_PTR_MASK;
if (type1 && type2) {
if (lhs_type != rhs_type) {
eprintf("pointer type mismatch\n");
exit(1);
}
if (lhs_type == TYPE_VOID_PTR) {
eprintf("void pointer cannot be arithmetically operated\n");
exit(1);
}
load(0, lhs);
load(1, rhs);
printf(" sub t0, t0, t1\n");
asm_shift_t0("srai", lhs_type);
return materialize_t0(TYPE_INT);
}
if (type1) {
int neg = asm_r_arith("neg", rhs);
return asm_add(lhs, neg);
}
return asm_rr("sub", lhs, rhs);
}
// parser
int parse_expr();
int parse_function_call(int id) {
const char* name = id_table + id_lut[id];
if (global_marker[id] != MARKER_FUNCTION) {
eprintf("not a function name: %s\n", name);
exit(1);
}
int arg = 0;
int args[8];
while (1) {
next_token();
if (token_type == TOKEN_PAREN_RIGHT) {
break;
}
unget_token();
if (arg >= 8) {
eprintf("too many arguments\n");
exit(1);
}
args[arg++] = parse_expr();
next_token();
if (token_type == TOKEN_COMMA) {
// continue;
} else if (token_type == TOKEN_PAREN_RIGHT) {
break;
} else {
eprintf("expecting ',' or ')'\n");
exit(1);
}
}
for (int i = 0; i < arg; ++i) {
load(0, args[i]);
printf(" mv a%d, t0\n", i);
}
printf(" call %s\n", name);
int type = global_type[id];
if (type != TYPE_VOID) {
printf(" mv t0, a0\n");
return materialize_t0(type);
}
return -1;
}
int parse_primary_expr() {
next_token();
if (token_type == TOKEN_EOF) {
exit(1);
} else if (token_type == TOKEN_NUMBER) {
printf(" li t0, %d\n", token_data);
return materialize_t0(TYPE_INT);
} else if (token_type == TOKEN_ID) {
next_token();
if (token_type == TOKEN_PAREN_LEFT) {
return parse_function_call(token_data);
}
unget_token();
return lookup(token_data);
} else if (token_type == TOKEN_STRING) {
printf(" la t0, .LC%d\n", token_data);
return materialize_t0(TYPE_CHAR_PTR);
} else if (token_type == TOKEN_PAREN_LEFT) {
int reg = parse_expr();
expect_token(TOKEN_PAREN_RIGHT);
return reg;
} else {
eprintf("unexpected token in primary expression: %d\n", token_type);
exit(1);
}
}
int parse_postfix_expr() {
int lhs = parse_primary_expr();
while (1) {
next_token();
if (token_type == TOKEN_INC) {
int type = local_type[lhs];
int reg = next_reg(type);
load(0, lhs);
store_t0(reg);
printf(" addi t0, t0, %d\n", step_of(type));
store_t0(lhs);
lhs = reg;
} else if (token_type == TOKEN_DEC) {
int type = local_type[lhs];
int reg = next_reg(type);
load(0, lhs);
store_t0(reg);
printf(" addi t0, t0, -%d\n", step_of(type));
store_t0(lhs);
lhs = reg;
} else if (token_type == TOKEN_BRACKET_LEFT) {
int rhs = parse_expr();
expect_token(TOKEN_BRACKET_RIGHT);
lhs = dereference(asm_add(lhs, rhs));
} else {
unget_token();
break;
}
}
return lhs;
}
int parse_prefix_expr() {
next_token();
if (token_type == TOKEN_AND) {
int reg = parse_postfix_expr();
int type = local_type[reg];
if (type & TYPE_PTR_MASK) {
eprintf("cannot take address of a pointer\n");
exit(1);
}
load_address(0, reg);
return materialize_t0(type | TYPE_PTR_MASK);
} else if (token_type == TOKEN_STAR) {
int reg = parse_postfix_expr();
int type = local_type[reg];
if (!(type & TYPE_PTR_MASK)) {
eprintf("cannot dereference a non-pointer\n");
exit(1);
}
if (type == TYPE_VOID_PTR) {
eprintf("cannot dereference void pointer\n");
exit(1);
}
load(0, reg);
return dereference(materialize_t0(type));
} else if (token_type == TOKEN_MINUS) {
int reg = parse_postfix_expr();
return asm_r_arith("neg", reg);
} else if (token_type == TOKEN_COMPL) {
int reg = parse_postfix_expr();
return asm_r_arith("not", reg);
} else if (token_type == TOKEN_NOT) {
int reg = parse_postfix_expr();
return asm_r("seqz", reg);
} else if (token_type == TOKEN_INC) {
int reg = parse_postfix_expr();
load(0, reg);
printf(" addi t0, t0, %d\n", step_of(local_type[reg]));
store_t0(reg);
return reg;
} else if (token_type == TOKEN_DEC) {
int reg = parse_postfix_expr();
load(0, reg);
printf(" addi t0, t0, -%d\n", step_of(local_type[reg]));
store_t0(reg);
return reg;
} else {
unget_token();
return parse_postfix_expr();
}
}
int parse_mul_expr() {
int lhs = parse_prefix_expr();
while (1) {
next_token();
if (token_type == TOKEN_STAR) {
int rhs = parse_prefix_expr();
lhs = asm_rr_arith("mul", lhs, rhs);
} else if (token_type == TOKEN_DIV) {
int rhs = parse_prefix_expr();
lhs = asm_rr_arith("div", lhs, rhs);
} else if (token_type == TOKEN_REM) {
int rhs = parse_prefix_expr();
lhs = asm_rr_arith("rem", lhs, rhs);
} else {
unget_token();
break;
}
}
return lhs;
}
int parse_add_expr() {
int lhs = parse_mul_expr();
while (1) {
next_token();
if (token_type == TOKEN_ADD) {
int rhs = parse_mul_expr();
lhs = asm_add(lhs, rhs);
} else if (token_type == TOKEN_MINUS) {
int rhs = parse_mul_expr();
lhs = asm_sub(lhs, rhs);
} else {
unget_token();
break;
}
}
return lhs;
}
int parse_shift_expr() {
int lhs = parse_add_expr();
while (1) {
next_token();
if (token_type == TOKEN_LSHIFT) {
int rhs = parse_add_expr();
lhs = asm_rr_arith("sll", lhs, rhs);
} else if (token_type == TOKEN_RSHIFT) {
int rhs = parse_add_expr();
lhs = asm_rr_arith("sra", lhs, rhs);
} else {
unget_token();
break;
}
}
return lhs;
}
int parse_cmp_expr() {
int lhs = parse_shift_expr();
while (1) {
next_token();
if (token_type == TOKEN_LT) {
int rhs = parse_shift_expr();
lhs = asm_rr_cmp("slt", lhs, rhs);
} else if (token_type == TOKEN_GT) {
int rhs = parse_shift_expr();
lhs = asm_rr_cmp("sgt", lhs, rhs);
} else if (token_type == TOKEN_LE) {
int rhs = parse_shift_expr();
int sgt = asm_rr_cmp("sgt", lhs, rhs);
lhs = asm_r("seqz", sgt);
} else if (token_type == TOKEN_GE) {
int rhs = parse_shift_expr();
int slt = asm_rr_cmp("slt", lhs, rhs);
lhs = asm_r("seqz", slt);
} else {
unget_token();
break;
}
}
return lhs;
}
int parse_eq_expr() {
int lhs = parse_cmp_expr();
while (1) {
next_token();
if (token_type == TOKEN_EQ) {
int rhs = parse_cmp_expr();
int xor0 = asm_rr_cmp("xor", lhs, rhs);
lhs = asm_r("seqz", xor0);
} else if (token_type == TOKEN_NE) {
int rhs = parse_cmp_expr();
int xor0 = asm_rr_cmp("xor", lhs, rhs);
lhs = asm_r("snez", xor0);
} else {
unget_token();
break;
}
}
return lhs;
}
int parse_bitwise_and_expr() {
int lhs = parse_eq_expr();
while (1) {
next_token();
if (token_type == TOKEN_AND) {
int rhs = parse_eq_expr();
lhs = asm_rr_arith("and", lhs, rhs);
} else {
unget_token();
break;
}
}
return lhs;
}
int parse_bitwise_xor_expr() {
int lhs = parse_bitwise_and_expr();
while (1) {
next_token();
if (token_type == TOKEN_XOR) {
int rhs = parse_bitwise_and_expr();
lhs = asm_rr_arith("xor", lhs, rhs);
} else {
unget_token();
break;
}
}
return lhs;
}
int parse_bitwise_or_expr() {
int lhs = parse_bitwise_xor_expr();
while (1) {
next_token();
if (token_type == TOKEN_OR) {
int rhs = parse_bitwise_xor_expr();
lhs = asm_rr_arith("or", lhs, rhs);
} else {
unget_token();
break;
}
}
return lhs;
}
int parse_logical_and_expr() {
int lhs = parse_bitwise_or_expr();
int label = next_label();
int label_used = 0;
while (1) {
next_token();
if (token_type == TOKEN_LAND) {
lhs = asm_r("snez", lhs);
asm_beqz(lhs, label);
int rhs = parse_bitwise_or_expr();
rhs = asm_r("snez", rhs);
lhs = asm_rr("and", lhs, rhs);
label_used = 1;
} else {
unget_token();
break;
}
}
if (label_used) {
asm_label(label);
}
return lhs;
}
int parse_logical_or_expr() {
int lhs = parse_logical_and_expr();
int label = next_label();
int label_used = 0;
while (1) {
next_token();
if (token_type == TOKEN_LOR) {
lhs = asm_r("snez", lhs);
asm_bnez(lhs, label);
int rhs = parse_logical_and_expr();
rhs = asm_r("snez", rhs);
lhs = asm_rr("or", lhs, rhs);
label_used = 1;
} else {
unget_token();
break;
}
}
if (label_used) {
asm_label(label);
}
return lhs;
}
int parse_assign_expr() {
int lhs = parse_logical_or_expr();
next_token();
if (token_type == TOKEN_ASSIGN) {
int rhs = parse_assign_expr();
load(0, rhs);
store_t0(lhs);
return lhs;
} else {
unget_token();
return lhs;
}
}
int parse_expr() {
return parse_assign_expr();
}
void parse_local_variable(int type) {
if (type == TYPE_VOID) {
eprintf("local variable of void type is not supported\n");
exit(1);
}
expect_token(TOKEN_ID);
int id = token_data;
next_token();
if (token_type == TOKEN_BRACKET_LEFT) {
if (type & TYPE_PTR_MASK) {
eprintf("local variable of array of pointers is not supported\n");
exit(1);
}
expect_token(TOKEN_NUMBER);
int size = token_data;
expect_token(TOKEN_BRACKET_RIGHT);
declare_local_array(id, type, size);
next_token();
} else {
declare_local(id, type);
}
if (token_type == TOKEN_SEMICOLON) {
unget_token();
return;
}
unget_token();
expect_token(TOKEN_ASSIGN);
int reg = parse_expr();
load(0, reg);
store_t0(local_table[id]);
}
void parse_stmt();
void parse_if() {
expect_token(TOKEN_PAREN_LEFT);
int cond = parse_expr();
int label1 = next_label();
int label2 = next_label();
asm_beqz(cond, label1);
reset_temp();
expect_token(TOKEN_PAREN_RIGHT);
parse_stmt();
asm_j(label2);
asm_label(label1);
next_token();
if (token_type == TOKEN_ELSE) {
parse_stmt();
} else {
unget_token();
}
asm_label(label2);
}
void parse_while() {
expect_token(TOKEN_PAREN_LEFT);
int break_label = next_label();
int cont_label = next_label();
asm_push_label(break_label, cont_label);
asm_label(cont_label);
int cond = parse_expr();
asm_beqz(cond, break_label);
reset_temp();
expect_token(TOKEN_PAREN_RIGHT);
parse_stmt();
asm_j(cont_label);
asm_label(break_label);
asm_pop_label();
}
void parse_for() {
expect_token(TOKEN_PAREN_LEFT);
int cont_label = next_label();
int break_label = next_label();
int cond_label = next_label();
int body_label = next_label();
asm_push_label(break_label, cont_label);
parse_stmt(); // init
asm_label(cond_label);
int cond = parse_expr();
asm_beqz(cond, break_label);
asm_j(body_label);
reset_temp();
expect_token(TOKEN_SEMICOLON);
asm_label(cont_label);
parse_expr(); // update
reset_temp();
expect_token(TOKEN_PAREN_RIGHT);
asm_j(cond_label);
asm_label(body_label);
parse_stmt(); // body
asm_j(cont_label);
asm_label(break_label);
asm_pop_label();
}
void parse_do_while() {
int cont_label = next_label();
int break_label = next_label();
asm_push_label(break_label, cont_label);
asm_label(cont_label);
parse_stmt(); // body
expect_token(TOKEN_WHILE);
expect_token(TOKEN_PAREN_LEFT);
int cond = parse_expr();
asm_bnez(cond, cont_label);
expect_token(TOKEN_PAREN_RIGHT);
asm_label(break_label);
asm_pop_label();
}
void parse_stmt() {
next_token();
int decl_type;
if (token_type == TOKEN_IF) {
parse_if();
return;
} else if (token_type == TOKEN_WHILE) {
parse_while();
return;
} else if (token_type == TOKEN_FOR) {
parse_for();
return;
} else if (token_type == TOKEN_DO) {
parse_do_while();
} else if (token_type == TOKEN_BRACE_LEFT) {
while (1) {
next_token();
if (token_type == TOKEN_BRACE_RIGHT) {
break;
}
unget_token();
parse_stmt();
}
return;
} else if (token_type == TOKEN_RETURN) {
next_token();
if (token_type == TOKEN_SEMICOLON) {
asm_j(epilog_label);
return;
}
unget_token();
int reg = parse_expr();
load(0, reg);
printf(" mv a0, t0\n");
asm_j(epilog_label);
} else if (token_type == TOKEN_BREAK) {
int label = asm_get_break_label();
asm_j(label);
} else if (token_type == TOKEN_CONTINUE) {
int label = asm_get_cont_label();
asm_j(label);
} else if (token_type == TOKEN_SEMICOLON) {
unget_token();
} else if ((decl_type = parse_type()) >= 0) {
parse_local_variable(decl_type);
} else {
unget_token();
parse_expr();
}
expect_token(TOKEN_SEMICOLON);
reset_temp();
}
void parse_function(const char* name) {
reset_local();
int arg = 0;
int args[8];
while (1) {
next_token();
if (token_type == TOKEN_PAREN_RIGHT) {
break;
}
if (token_type == TOKEN_ELLIPSIS) {
expect_token(TOKEN_PAREN_RIGHT);
break;
}
if (token_type == TOKEN_VOID) {
if (arg != 0) {
eprintf("void should be the only argument\n");
exit(1);
}
expect_token(TOKEN_PAREN_RIGHT);
break;
}
int arg_type = parse_type();
if (arg_type < 0 || arg_type == TYPE_VOID) {
eprintf("unexpected a non-void argument type");
exit(1);
}
expect_token(TOKEN_ID);
int arg_name = token_data;
next_token();
if (token_type == TOKEN_BRACKET_LEFT) {
expect_token(TOKEN_BRACKET_RIGHT);
next_token();
if (arg_type & TYPE_PTR_MASK) {
eprintf("local variable of array of pointers is not supported\n");
exit(1);
}
arg_type = arg_type | TYPE_PTR_MASK;
}
args[arg++] = declare_local(token_data, arg_type);
if (token_type == TOKEN_COMMA) {
// continue;
} else if (token_type == TOKEN_PAREN_RIGHT) {
break;
} else {
eprintf("expecting ',' or ')'\n");
exit(1);
}
}
next_token();
if (token_type == TOKEN_SEMICOLON) {
return;
}
unget_token();
expect_token(TOKEN_BRACE_LEFT);
printf(".text\n");
printf(".global %s\n", name);
printf("%s:\n", name);
int label = next_label();
int prolog_label = next_label();
epilog_label = next_label();
asm_j(prolog_label);
asm_label(label);
while (1) {
next_token();
if (token_type == TOKEN_BRACE_RIGHT) {
break;
}
unget_token();
parse_stmt();
}
asm_j(epilog_label);
int frame_size = max_local_id * 8;
if (frame_size % 16 != 0) {
frame_size = frame_size + 8;
}
// prolog
asm_label(prolog_label);
asm_addi("sp", "sp", -frame_size);
asm_sd("ra", frame_size - 8, "sp");
asm_sd("fp", frame_size - 16, "sp");
asm_addi("fp", "sp", frame_size);
for (int i = 0; i < arg; ++i) {
printf(" mv t0, a%d\n", i);
store_t0(args[i]);
}
asm_j(label);
// epilog
asm_label(epilog_label);
asm_ld("fp", frame_size - 16, "sp");
asm_ld("ra", frame_size - 8, "sp");
asm_addi("sp", "sp", frame_size);
printf(" ret\n");
}
void parse_global_variable(int id, const char* name, int type) {
if (type == TYPE_VOID) {
eprintf("global variable of void type is not supported\n");
exit(1);
}
if (type & TYPE_PTR_MASK) {
eprintf("global variable of pointer is not supported\n");
exit(1);
}
printf(".data\n");
printf(".globl %s\n", name);
printf(".align 5\n");
printf("%s:\n", name);
if (token_type == TOKEN_ASSIGN) {
expect_token(TOKEN_NUMBER);
printf(" .word %d\n", token_data);
} else if (token_type == TOKEN_BRACKET_LEFT) {
expect_token(TOKEN_NUMBER);
int size = token_data;
expect_token(TOKEN_BRACKET_RIGHT);
int array_size = 4 * size;
if (type == TYPE_CHAR) {
array_size = size;
}
printf(" .zero %d\n", array_size);
declare_global(id, MARKER_ARRAY, type);
} else {
printf(" .zero %d\n", 4);
unget_token();
}
expect_token(TOKEN_SEMICOLON);
}
void parse_global_declaration() {
int type = parse_type();
if (type < 0) {
eprintf("expecting type for global declaration\n");
exit(1);
}
expect_token(TOKEN_ID);
int id = token_data;
char* name = id_table + id_lut[id];
next_token();
if (token_type == TOKEN_PAREN_LEFT) {
declare_global(id, MARKER_FUNCTION, type);
parse_function(name);
} else {
declare_global(id, MARKER_SCALAR, type);
parse_global_variable(id, name, type);
}
}
void parse_top_level() {
next_token();
if (token_type == TOKEN_EOF)
return;
parse_global_declaration();
parse_top_level();
}
void dump_string_table() {
printf(".data\n");
for (int i = 0; i < string_lut_size; ++i) {
printf(".LC%d: .string \"", i);
int offset = string_lut[i];
int ch;
while ((ch = string_table[offset++]) != 0) {
if (ch == '\n') {
printf("\\n");
} else if (ch == '\t') {
printf("\\t");
} else if (ch == '\r') {
printf("\\r");
} else if (ch == '\0') {
printf("\\0");
} else if (ch == '\\') {
printf("\\\\");
} else if (ch == '\'') {
printf("\\'");
} else if (ch == '\"') {
printf("\\\"");
} else {
printf("%c", ch);
}
}
printf("\"\n");
}
}
int main() {
parse_top_level();
dump_string_table();
return 0;
}
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