Commit 7be66813 authored by Alexander Hirsch's avatar Alexander Hirsch
Browse files

Lab: Add basic TAC example

parent 9d2386b3
CFLAGS = -std=c17 -Wall -Wextra
all: tac
clean:
$(RM) tac
.PHONY: all clean
#include <assert.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
// -------------------------------------------------------------------- TAC Definition
enum tac_variable_type {
TAC_VARIABLE_TYPE_VOID = 0,
TAC_VARIABLE_TYPE_INT,
TAC_VARIABLE_TYPE_FLOAT,
};
const char *tac_variable_type_to_string(enum tac_variable_type type)
{
switch (type) {
case TAC_VARIABLE_TYPE_VOID:
return "void";
case TAC_VARIABLE_TYPE_INT:
return "int";
case TAC_VARIABLE_TYPE_FLOAT:
return "float";
}
assert(false);
return "INVALID";
}
struct tac_variable {
enum tac_variable_type type;
uint64_t identifier;
};
void tac_variable_print(const struct tac_variable *variable)
{
assert(variable);
if (variable->type == TAC_VARIABLE_TYPE_VOID) {
printf("unused");
} else {
printf("v%ld", variable->identifier);
}
}
enum tac_instruction_op {
TAC_INSTRUCTION_OP_CONST,
TAC_INSTRUCTION_OP_ASSIGN,
// Arithmetic operations
TAC_INSTRUCTION_OP_ADD,
// ...
// Control flow
TAC_INSTRUCTION_OP_LABEL,
TAC_INSTRUCTION_OP_JUMP,
TAC_INSTRUCTION_OP_JUMP_IF,
// Function calls
TAC_INSTRUCTION_OP_CALL,
TAC_INSTRUCTION_OP_RETURN,
TAC_INSTRUCTION_OP_PUSH,
TAC_INSTRUCTION_OP_POP,
};
const char *tac_instruction_op_to_string(enum tac_instruction_op op)
{
switch (op) {
case TAC_INSTRUCTION_OP_CONST:
return "CONST";
case TAC_INSTRUCTION_OP_ASSIGN:
return "ASSIGN";
case TAC_INSTRUCTION_OP_ADD:
return "ADD";
case TAC_INSTRUCTION_OP_LABEL:
return "LABEL";
case TAC_INSTRUCTION_OP_JUMP:
return "JUMP";
case TAC_INSTRUCTION_OP_JUMP_IF:
return "JUMP_IF";
case TAC_INSTRUCTION_OP_CALL:
return "CALL";
case TAC_INSTRUCTION_OP_RETURN:
return "RETURN";
case TAC_INSTRUCTION_OP_PUSH:
return "PUSH";
case TAC_INSTRUCTION_OP_POP:
return "POP";
}
assert(false);
return "INVALID";
}
struct tac_function {
const char name[256];
// Using a singly linked list here for convenience, although it is super
// inefficient.
struct tac_instruction *start;
};
struct tac_instruction {
enum tac_instruction_op op;
struct tac_variable arg1, arg2, result;
union {
long int_constant;
double float_constant;
};
uint64_t label;
const char *function;
struct tac_instruction *next;
};
// -------------------------------------------------------------------- TAC Generator
struct tac_variable gen_variable(enum tac_variable_type type)
{
static uint64_t variable_index = 1;
return (struct tac_variable){
.type = type,
.identifier = variable_index++,
};
}
struct tac_instruction *gen_label(void)
{
static uint64_t label_index = 1;
struct tac_instruction *result = malloc(sizeof(*result));
assert(result);
*result = (struct tac_instruction){
.op = TAC_INSTRUCTION_OP_LABEL,
.label = label_index++,
};
return result;
}
struct tac_instruction *gen_const_int(long value)
{
struct tac_instruction *result = malloc(sizeof(*result));
assert(result);
*result = (struct tac_instruction){
.op = TAC_INSTRUCTION_OP_CONST,
.result = gen_variable(TAC_VARIABLE_TYPE_INT),
.int_constant = value,
};
return result;
}
struct tac_instruction *gen_const_float(double value)
{
struct tac_instruction *result = malloc(sizeof(*result));
assert(result);
*result = (struct tac_instruction){
.op = TAC_INSTRUCTION_OP_CONST,
.result = gen_variable(TAC_VARIABLE_TYPE_FLOAT),
.float_constant = value,
};
return result;
}
struct tac_instruction *gen_assign(struct tac_variable lhs, struct tac_variable rhs)
{
assert(lhs.type == rhs.type);
struct tac_instruction *result = malloc(sizeof(*result));
assert(result);
*result = (struct tac_instruction){
.op = TAC_INSTRUCTION_OP_ASSIGN,
.arg1 = rhs,
.result = lhs,
};
return result;
}
struct tac_instruction *gen_add(struct tac_variable lhs, struct tac_variable rhs)
{
assert(lhs.type == rhs.type);
struct tac_instruction *result = malloc(sizeof(*result));
assert(result);
*result = (struct tac_instruction){
.op = TAC_INSTRUCTION_OP_ADD,
.arg1 = lhs,
.arg2 = rhs,
.result = gen_variable(lhs.type),
};
return result;
}
struct tac_instruction *gen_jump(uint64_t label)
{
assert(label != 0);
struct tac_instruction *result = malloc(sizeof(*result));
assert(result);
*result = (struct tac_instruction){
.op = TAC_INSTRUCTION_OP_JUMP,
.label = label,
};
return result;
}
struct tac_instruction *gen_jump_if(uint64_t label, struct tac_variable condition)
{
assert(label != 0);
assert(condition.type == TAC_VARIABLE_TYPE_INT);
struct tac_instruction *result = malloc(sizeof(*result));
assert(result);
*result = (struct tac_instruction){
.op = TAC_INSTRUCTION_OP_JUMP_IF,
.arg1 = condition,
.label = label,
};
return result;
}
struct tac_instruction *gen_call(const char *function, enum tac_variable_type result_type)
{
struct tac_instruction *result = malloc(sizeof(*result));
assert(result);
*result = (struct tac_instruction){
.op = TAC_INSTRUCTION_OP_CALL,
.result = gen_variable(result_type),
.function = function,
};
return result;
}
struct tac_instruction *gen_return()
{
struct tac_instruction *result = malloc(sizeof(*result));
assert(result);
*result = (struct tac_instruction){
.op = TAC_INSTRUCTION_OP_RETURN,
};
return result;
}
struct tac_instruction *gen_return_variable(struct tac_variable arg1)
{
struct tac_instruction *result = malloc(sizeof(*result));
assert(result);
*result = (struct tac_instruction){
.op = TAC_INSTRUCTION_OP_RETURN,
.arg1 = arg1,
};
return result;
}
struct tac_instruction *gen_push(struct tac_variable variable)
{
struct tac_instruction *result = malloc(sizeof(*result));
assert(result);
*result = (struct tac_instruction){
.op = TAC_INSTRUCTION_OP_PUSH,
.arg1 = variable,
};
return result;
}
struct tac_instruction *gen_pop(enum tac_variable_type result_type)
{
struct tac_instruction *result = malloc(sizeof(*result));
assert(result);
*result = (struct tac_instruction){
.op = TAC_INSTRUCTION_OP_POP,
.result = gen_variable(result_type),
};
return result;
}
void append_instruction(struct tac_function *function, struct tac_instruction *instruction)
{
assert(function);
assert(instruction);
struct tac_instruction **end = &function->start;
while (*end) {
end = &(*end)->next;
}
*end = instruction;
}
void clear_instructions(struct tac_function *function)
{
assert(function);
struct tac_instruction *current = function->start;
while (current) {
struct tac_instruction *to_free = current;
current = current->next;
free(to_free);
}
}
void print_instructions(struct tac_function *function)
{
assert(function);
printf("==== %s ====\n", function->name);
for (struct tac_instruction *instruction = function->start; instruction; instruction = instruction->next) {
printf("%s\t", tac_instruction_op_to_string(instruction->op));
if (instruction->result.type != TAC_VARIABLE_TYPE_VOID) {
tac_variable_print(&instruction->result);
printf("\t%s\t", tac_variable_type_to_string(instruction->result.type));
} else {
printf("\t\t");
}
switch (instruction->op) {
case TAC_INSTRUCTION_OP_CONST:
if (instruction->result.type == TAC_VARIABLE_TYPE_INT) {
printf("%ld", instruction->int_constant);
} else {
printf("%f", instruction->float_constant);
}
break;
case TAC_INSTRUCTION_OP_ADD:
tac_variable_print(&instruction->arg1);
printf("\t");
tac_variable_print(&instruction->arg2);
break;
case TAC_INSTRUCTION_OP_LABEL:
case TAC_INSTRUCTION_OP_JUMP:
printf("L_%ld", instruction->label);
break;
case TAC_INSTRUCTION_OP_JUMP_IF:
printf("L_%ld\t", instruction->label);
tac_variable_print(&instruction->arg1);
break;
case TAC_INSTRUCTION_OP_CALL:
printf("%s", instruction->function);
break;
case TAC_INSTRUCTION_OP_RETURN:
if (instruction->arg1.type != TAC_VARIABLE_TYPE_VOID) {
tac_variable_print(&instruction->arg1);
}
break;
case TAC_INSTRUCTION_OP_ASSIGN:
case TAC_INSTRUCTION_OP_PUSH:
tac_variable_print(&instruction->arg1);
break;
case TAC_INSTRUCTION_OP_POP:
break;
default:
assert(false);
break;
}
printf("\n");
}
}
// --------------------------------------------------------------------
int main(void)
{
struct tac_function my_function = {
.name = "My TAC Function",
};
struct tac_instruction *inst1 = gen_pop(TAC_VARIABLE_TYPE_INT);
append_instruction(&my_function, inst1);
struct tac_instruction *c1 = gen_const_int(1);
append_instruction(&my_function, c1);
struct tac_instruction *c2 = gen_const_int(2);
append_instruction(&my_function, c2);
struct tac_instruction *inst2 = gen_add(c1->result, c2->result);
append_instruction(&my_function, inst2);
struct tac_instruction *inst3 = gen_add(inst2->result, inst1->result);
append_instruction(&my_function, inst3);
struct tac_instruction *l1 = gen_label();
struct tac_instruction *inst4 = gen_jump_if(l1->label, inst3->result);
append_instruction(&my_function, inst4);
struct tac_instruction *inst5 = gen_add(inst3->result, c1->result);
append_instruction(&my_function, inst5);
append_instruction(&my_function, gen_assign(inst3->result, inst5->result));
struct tac_instruction *l2 = gen_label();
struct tac_instruction *inst7 = gen_jump(l2->label);
append_instruction(&my_function, inst7);
append_instruction(&my_function, l1);
struct tac_instruction *inst8 = gen_add(inst3->result, c2->result);
append_instruction(&my_function, inst8);
append_instruction(&my_function, gen_assign(inst3->result, inst8->result));
append_instruction(&my_function, l2);
append_instruction(&my_function, gen_push(c2->result));
append_instruction(&my_function, gen_push(c1->result));
append_instruction(&my_function, gen_push(inst3->result));
struct tac_instruction *inst9 = gen_call("some_function", TAC_VARIABLE_TYPE_FLOAT);
append_instruction(&my_function, inst9);
append_instruction(&my_function, gen_return_variable(inst9->result));
print_instructions(&my_function);
clear_instructions(&my_function);
return EXIT_SUCCESS;
}
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