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#ifndef BDL_COMPILER_H
#define BDL_COMPILER_H
#define PRELUDE_FILE "src/x86_64/prelude.asm"
#define POSTLUDE_FILE "src/x86_64/postlude.asm"
#define HEAP_SIZE MB(32)
// Immediate constants.
#define NIL_VAL 47
#define BOOL_MASK 127
#define BOOL_TAG 31
#define BOOL_SHIFT 7
#define TRUE_VAL ((1 << BOOL_SHIFT) | BOOL_TAG)
#define FALSE_VAL ((0 << BOOL_SHIFT) | BOOL_TAG)
#define FIXNUM_MASK 3
#define FIXNUM_TAG 0
#define FIXNUM_SHIFT 2
// Heap allocated objects.
#define STRING_MASK 7
#define STRING_TAG 3
#define PAIR_MASK 7
#define PAIR_TAG 1
void compile_object(Object *obj);
void compile_fixnum(Object *obj);
void compile_proc_call(Object *obj);
void compile(Root *roots);
char *
generate_label(void) {
// Generate a unique label allocated on the heap. The caller is responsible
// for freeing the memory.
static size_t label_counter = 0;
char buf[32];
sprintf(buf, ".BDLL%ld", label_counter++);
size_t len = strlen(buf);
char * ret = malloc(len + 1);
memcpy(ret, buf, len);
ret[len] = 0;
return ret;
}
void
emit_file(char *file_name) {
FILE *file = fopen(file_name, "r");
if (!file) {
fprintf(stderr, "error: couldn't open input file: %s\n", file_name);
exit(EXIT_FAILURE);
}
char buf[1024];
size_t n = 0;
while ((n = fread(&buf, 1, 1024, file)) > 0) {
fwrite(buf, 1, n, stdout);
}
}
void
compile_fixnum(Object *obj) {
printf(" ;; --> compile_fixnum\n");
printf(" mov rax, %ld\n", (obj->fixnum << FIXNUM_SHIFT) | FIXNUM_TAG);
printf(" push rax\n");
printf(" ;; <-- compile_fixnum\n");
}
void
compile_boolean(Object *obj) {
printf(" ;; --> compile_boolean\n");
int is_true = obj->type == OBJ_TYPE_TRUE;
printf(" mov rax, %d\n", (is_true << BOOL_SHIFT) | BOOL_TAG);
printf(" push rax\n");
printf(" ;; <-- compile_boolean\n");
}
void
compile_nil(void) {
printf(" ;; --> compile_nil\n");
printf(" mov rax, %d\n", NIL_VAL);
printf(" push rax\n");
printf(" ;; <-- compile_nil\n");
}
typedef enum OpType {
// Arithmetic.
OP_ADD,
OP_SUB,
OP_MUL,
OP_DIV,
OP_MOD,
// Type predicates.
OP_IS_NIL,
OP_IS_ZERO,
OP_IS_BOOL,
OP_IS_FIXNUM,
// Logic operations.
OP_EQUAL,
OP_GREATER,
OP_LESS,
OP_GREATER_EQ,
OP_LESS_EQ,
} OpType;
void
compile_type_predicate(OpType op, Object* args) {
printf(" ;; --> compile_type_predicate\n");
compile_object(args->head);
printf(" pop rax\n");
switch (op) {
case OP_IS_NIL: {
printf(" cmp rax, %d\n", NIL_VAL);
} break;
case OP_IS_ZERO: {
printf(" cmp rax, 0\n");
} break;
case OP_IS_BOOL: {
printf(" and rax, %d\n", BOOL_MASK);
printf(" cmp rax, %d\n", BOOL_TAG);
} break;
case OP_IS_FIXNUM: {
printf(" and rax, %d\n", FIXNUM_MASK);
printf(" cmp rax, %d\n", FIXNUM_TAG);
} break;
default: break;
}
printf(" mov rax, 0\n");
printf(" sete al\n");
printf(" shl rax, %d\n", BOOL_SHIFT);
printf(" or rax, %d\n", BOOL_TAG);
printf(" push rax\n");
printf(" ;; <-- compile_type_predicate\n");
}
void
compile_not(Object* args) {
printf(" ;; --> compile_not\n");
compile_object(args->head);
printf(" pop rax\n");
printf(" cmp rax, %d\n", FALSE_VAL);
printf(" mov rax, 0\n");
printf(" sete al\n");
printf(" shl rax, %d\n", BOOL_SHIFT);
printf(" or rax, %d\n", BOOL_TAG);
printf(" push rax\n");
printf(" ;; <-- compile_not\n");
}
void
compile_and(Object *args) {
printf(" ;; --> compile_and\n");
char *lab_false = generate_label();
char *lab_exit = generate_label();
while (args != NULL) {
compile_object(args->head);
args = args->tail;
printf(" pop rax\n");
printf(" cmp rax, %d\n", FALSE_VAL);
printf(" je %s\n", lab_false);
}
printf(" mov rax, %d\n", TRUE_VAL);
printf(" push rax\n");
printf(" jmp %s\n", lab_exit);
printf("%s:\n", lab_false);
printf(" mov rax, %d\n", FALSE_VAL);
printf(" push rax\n");
printf("%s:\n", lab_exit);
free(lab_false);
free(lab_exit);
printf(" ;; <-- compile_and\n");
}
void
compile_or(Object *args) {
printf(" ;; --> compile_or\n");
char *lab_true = generate_label();
char *lab_exit = generate_label();
while (args != NULL) {
compile_object(args->head);
args = args->tail;
printf(" pop rax\n");
printf(" cmp rax, %d\n", FALSE_VAL);
printf(" jne %s\n", lab_true);
}
printf(" mov rax, %d\n", FALSE_VAL);
printf(" push rax\n");
printf(" jmp %s\n", lab_exit);
printf("%s:\n", lab_true);
printf(" mov rax, %d\n", TRUE_VAL);
printf(" push rax\n");
printf("%s:\n", lab_exit);
free(lab_true);
free(lab_exit);
printf(" ;; <-- compile_or\n");
}
void
compile_cmp_list(OpType op, Object* args) {
printf(" ;; --> compile_cmp_list\n");
compile_object(args->head);
char *lab_false = generate_label();
char *lab_exit = generate_label();
args = args->tail;
while (args != NULL) {
compile_object(args->head);
args = args->tail;
// Current value.
printf(" pop rcx\n");
// Previous value.
printf(" pop rax\n");
// Comparison.
printf(" cmp rax, rcx\n");
switch (op) {
case OP_EQUAL: { printf(" jne %s\n", lab_false); } break;
case OP_GREATER: { printf(" jle %s\n", lab_false); } break;
case OP_LESS: { printf(" jge %s\n", lab_false); } break;
case OP_GREATER_EQ: { printf(" jl %s\n", lab_false); } break;
case OP_LESS_EQ: { printf(" jg %s\n", lab_false); } break;
default: break;
}
printf(" push rcx\n");
}
printf(" pop rcx\n");
printf(" mov rax, %d\n", TRUE_VAL);
printf(" push rax\n");
printf(" jmp %s\n", lab_exit);
printf("%s:\n", lab_false);
printf(" mov rax, %d\n", FALSE_VAL);
printf(" push rax\n");
printf("%s:\n", lab_exit);
free(lab_false);
free(lab_exit);
printf(" ;; <-- compile_cmp_list\n");
}
void
compile_arithmetic_list(OpType op, Object* args) {
printf(" ;; --> compile_arithmetic\n");
compile_object(args->head);
args = args->tail;
while (args != NULL) {
compile_object(args->head);
args = args->tail;
printf(" pop rcx\n");
printf(" pop rax\n");
switch (op) {
case OP_ADD: { printf(" add rax, rcx\n"); } break;
case OP_SUB: { printf(" sub rax, rcx\n"); } break;
case OP_MUL: {
printf(" sar rax, %d\n", FIXNUM_SHIFT);
printf(" sar rcx, %d\n", FIXNUM_SHIFT);
printf(" mul rcx\n");
printf(" shl rax, %d\n", FIXNUM_SHIFT);
} break;
case OP_DIV: {
printf(" sar rax, %d\n", FIXNUM_SHIFT);
printf(" sar rcx, %d\n", FIXNUM_SHIFT);
printf(" mov rdx, 0\n");
printf(" div rcx\n");
printf(" shl rax, %d\n", FIXNUM_SHIFT);
} break;
case OP_MOD: {
printf(" sar rax, %d\n", FIXNUM_SHIFT);
printf(" sar rcx, %d\n", FIXNUM_SHIFT);
printf(" mov rdx, 0\n");
printf(" div rcx\n");
printf(" mov rax, rdx\n");
printf(" shl rax, %d\n", FIXNUM_SHIFT);
} break;
default: break;
}
printf(" push rax\n");
}
printf(" ;; <-- compile_arithmetic\n");
}
void
compile_cons(Object *obj) {
printf(" ;; --> compile_cons\n");
// Store objects into the car and cdr.
compile_object(obj->head);
compile_object(obj->tail->head);
printf(" pop rdx\n");
printf(" pop rax\n");
printf(" mov [rsi], rax\n");
printf(" mov [rsi + 8], rdx\n");
// Push memory address of cons cell.
printf(" mov rax, rsi\n");
printf(" or rax, %ld\n", PAIR_TAG);
printf(" push rax\n");
// Bump allocation register.
printf(" add rsi, 16\n");
printf(" ;; <-- compile_cons\n");
}
void
compile_car(Object *obj) {
printf(" ;; <-- compile_car\n");
compile_object(obj->head);
printf(" pop rax\n");
printf(" and eax, %ld\n", ~PAIR_MASK);
printf(" mov rdx, [rax]\n");
printf(" push rdx\n");
printf(" ;; <-- compile_car\n");
}
void
compile_cdr(Object *obj) {
printf(" ;; <-- compile_cdr\n");
compile_object(obj->head);
printf(" pop rax\n");
printf(" and eax, %ld\n", ~PAIR_MASK);
printf(" mov rdx, [rax + 8]\n");
printf(" push rdx\n");
printf(" ;; <-- compile_cdr\n");
}
void
compile_proc_call(Object *obj) {
// TODO: Probably we want to use a hash table for these lookups that is
// initialized at the start of the compilation procedure.
if (sv_equal(&obj->head->text, &STRING("+"))) {
compile_arithmetic_list(OP_ADD, obj->tail);
} else if (sv_equal(&obj->head->text, &STRING("-"))) {
compile_arithmetic_list(OP_SUB, obj->tail);
} else if (sv_equal(&obj->head->text, &STRING("*"))) {
compile_arithmetic_list(OP_MUL, obj->tail);
} else if (sv_equal(&obj->head->text, &STRING("/"))) {
compile_arithmetic_list(OP_DIV, obj->tail);
} else if (sv_equal(&obj->head->text, &STRING("%"))) {
compile_arithmetic_list(OP_MOD, obj->tail);
} else if (sv_equal(&obj->head->text, &STRING("nil?"))) {
compile_type_predicate(OP_IS_NIL, obj->tail);
} else if (sv_equal(&obj->head->text, &STRING("zero?"))) {
compile_type_predicate(OP_IS_ZERO, obj->tail);
} else if (sv_equal(&obj->head->text, &STRING("fixnum?"))) {
compile_type_predicate(OP_IS_FIXNUM, obj->tail);
} else if (sv_equal(&obj->head->text, &STRING("bool?"))) {
compile_type_predicate(OP_IS_BOOL, obj->tail);
} else if (sv_equal(&obj->head->text, &STRING("display"))) {
compile_object(obj->tail->head);
printf(" pop rdi\n");
printf(" call display\n");
} else if (sv_equal(&obj->head->text, &STRING("not"))) {
compile_not(obj->tail);
} else if (sv_equal(&obj->head->text, &STRING("and"))) {
compile_and(obj->tail);
} else if (sv_equal(&obj->head->text, &STRING("or"))) {
compile_or(obj->tail);
} else if (sv_equal(&obj->head->text, &STRING("="))) {
compile_cmp_list(OP_EQUAL, obj->tail);
} else if (sv_equal(&obj->head->text, &STRING(">"))) {
compile_cmp_list(OP_GREATER, obj->tail);
} else if (sv_equal(&obj->head->text, &STRING("<"))) {
compile_cmp_list(OP_LESS, obj->tail);
} else if (sv_equal(&obj->head->text, &STRING(">="))) {
compile_cmp_list(OP_GREATER_EQ, obj->tail);
} else if (sv_equal(&obj->head->text, &STRING("<="))) {
compile_cmp_list(OP_LESS_EQ, obj->tail);
} else if (sv_equal(&obj->head->text, &STRING("cons"))) {
compile_cons(obj->tail);
} else if (sv_equal(&obj->head->text, &STRING("car"))) {
compile_car(obj->tail);
} else if (sv_equal(&obj->head->text, &STRING("cdr"))) {
compile_cdr(obj->tail);
} else {
fprintf(stderr, "error: not implemented\n");
exit(EXIT_FAILURE);
}
}
void
compile_if(Object *obj) {
char *lab_false = generate_label();
compile_object(obj->condition);
printf(" pop rax\n");
printf(" cmp rax, %d\n", FALSE_VAL);
printf(" je %s\n", lab_false);
compile_object(obj->expr_true);
if (obj->expr_false != NULL) {
char *lab_exit = generate_label();
printf(" jmp %s\n", lab_exit);
printf("%s:\n", lab_false);
compile_object(obj->expr_false);
printf("%s:\n", lab_exit);
free(lab_exit);
} else {
printf("%s:\n", lab_false);
}
free(lab_false);
}
void
compile_object(Object *obj) {
switch (obj->type) {
case OBJ_TYPE_NIL: { compile_nil(); } break;
case OBJ_TYPE_TRUE:
case OBJ_TYPE_FALSE: { compile_boolean(obj); } break;
case OBJ_TYPE_FIXNUM: { compile_fixnum(obj); } break;
case OBJ_TYPE_PAIR: { compile_proc_call(obj); } break;
case OBJ_TYPE_IF: { compile_if(obj); } break;
default: break;
}
}
void
compile(Root *roots) {
printf("%%define NIL_VAL %d\n", NIL_VAL);
printf("%%define BOOL_MASK %d\n", BOOL_MASK);
printf("%%define BOOL_TAG %d\n", BOOL_TAG);
printf("%%define BOOL_SHIFT %d\n", BOOL_SHIFT);
printf("%%define FIXNUM_MASK %d\n", FIXNUM_MASK);
printf("%%define FIXNUM_TAG %d\n", FIXNUM_TAG);
printf("%%define FIXNUM_SHIFT %d\n", FIXNUM_SHIFT);
printf("%%define HEAP_SIZE %ld\n", HEAP_SIZE);
printf("\n");
emit_file(PRELUDE_FILE);
for (size_t i = 0; i < array_size(roots); i++) {
Object *root = roots[i];
compile_object(root);
}
emit_file(POSTLUDE_FILE);
}
#endif // BDL_COMPILER_H
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