Lab: Add basic TAC example

lab/tac/.gitignore

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+tac

lab/tac/Makefile

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+CFLAGS = -std=c17 -Wall -Wextra
+
+all: tac
+
+clean:
+	$(RM) tac
+
+.PHONY: all clean

lab/tac/tac.c

@@ -0,0 +1,439 @@
+#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;
+}