Rename `cup` directory to `src`

1 files changed, 562 insertions, 0 deletions

diff --git a/src/parser.c b/src/parser.c
new file mode 100644
index 0000000..cfb5d97
--- /dev/null
+++ b/src/parser.c
@@ -0,0 +1,562 @@
+#include "parser.h"
+#include "utils.h"
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+#define MAX_FUNCTION_COUNT 1024
+static Node *all_functions[MAX_FUNCTION_COUNT];
+static i64 function_count = 0;
+
+static Node *current_function = NULL;
+
+#define BLOCK_STACK_SIZE 64
+static Node *block_stack[BLOCK_STACK_SIZE];
+static i64 block_stack_count = 0;
+static i64 cur_stack_offset = 0;
+
+
+Token do_assert_token(Token token, TokenType type, char *filename, int line)
+{
+    if (token.type != type) {
+        Location_print(stderr, token.loc);
+        fprintf(stderr, ": Expected token of type `%s` but got `%s`\n", token_type_to_str(type), token_type_to_str(token.type));
+        fprintf(stderr, "Relevant location in compiler: %s:%d\n", filename, line);
+        exit(1);
+    }
+    return token;
+}
+
+#define assert_token(token, type) do_assert_token(token, type, __FILE__, __LINE__)
+
+/******
+ * Some helpers
+ */
+
+NodeType binary_token_to_op(TokenType type)
+{
+    switch (type)
+    {
+        case TOKEN_PLUS:    return OP_PLUS;
+        case TOKEN_MINUS:   return OP_MINUS;
+        case TOKEN_STAR:    return OP_MUL;
+        case TOKEN_SLASH:   return OP_DIV;
+        case TOKEN_PERCENT: return OP_MOD;
+        case TOKEN_LSHIFT:  return OP_LSHIFT;
+        case TOKEN_RSHIFT:  return OP_RSHIFT;
+        case TOKEN_AND:     return OP_AND;
+        case TOKEN_OR:      return OP_OR;
+        case TOKEN_XOR:     return OP_XOR;
+        case TOKEN_EQ:      return OP_EQ;
+        case TOKEN_NEQ:     return OP_NEQ;
+        case TOKEN_LT:      return OP_LT;
+        case TOKEN_LEQ:     return OP_LEQ;
+        case TOKEN_GT:      return OP_GT;
+        case TOKEN_GEQ:     return OP_GEQ;
+        
+        default: assert(false && "binary_token_to_op called with invalid token type");
+    }
+}
+
+void block_stack_push(Node *block)
+{
+    assert(block_stack_count < BLOCK_STACK_SIZE);
+    assert(current_function);
+    block_stack[block_stack_count++] = block;
+}
+
+void block_stack_pop()
+{
+    assert(block_stack_count > 0);
+    assert(current_function);
+    Node *block = block_stack[--block_stack_count];
+    cur_stack_offset -= block->block.locals_size;
+    assert(cur_stack_offset >= 0);
+}
+
+void dump_block_stack()
+{
+    for (i64 i = 0; i < block_stack_count; i++) {
+        Node *block = block_stack[i];
+        for (int i = 0; i < block->block.num_locals; i++) {
+            printf("%s: offset: %lld\n", block->block.locals[i]->name, block->block.locals[i]->offset);
+        }
+        printf("\n");
+    }
+}
+
+Variable *find_local_variable(Token *token)
+{
+    assert_token(*token, TOKEN_IDENTIFIER);
+    for (i64 i = block_stack_count - 1; i >= 0; --i) {
+        Node *block = block_stack[i];
+        for (int i = 0; i < block->block.num_locals; i++) {
+            if (strcmp(block->block.locals[i]->name, token->value.as_string) == 0) {
+                return block->block.locals[i];
+            }
+        }
+    }
+    Node *func = current_function;
+    for (int i = 0; i < func->func.num_args; i++) {
+        if (strcmp(func->func.args[i].name, token->value.as_string) == 0) {
+            return &func->func.args[i];
+        }
+    }
+    return NULL;
+}
+
+Node *find_function_definition(Token *token)
+{
+    assert_token(*token, TOKEN_IDENTIFIER);
+    for (i64 i = 0; i < function_count; i++) {
+        Node *function = all_functions[i];
+        if (strcmp(function->func.name, token->value.as_string) == 0) {
+            return function;
+        }
+    }
+    return NULL;
+}
+
+// TODO: rename this, it's ugly
+void add_variable_to_current_block(Variable *var)
+{
+    // Set offset for variable
+    Node *cur_block = block_stack[block_stack_count - 1];
+    var->offset = cur_stack_offset;
+
+    int new_len = (cur_block->block.num_locals + 1);
+    int var_size = 8; // TODO: Compute sizes based on different types
+    
+    // Add to the block
+    // FIXME: Use a map here
+    cur_block->block.locals = realloc(cur_block->block.locals, sizeof(Variable *) * new_len);
+    cur_block->block.locals[cur_block->block.num_locals] = var;
+    cur_block->block.num_locals++;
+
+    assert(current_function);
+    // Update current stack offset (w.r.t function stack frame) and block size
+    cur_stack_offset += var_size;
+    block_stack[block_stack_count-1]->block.locals_size += var_size;
+    
+    // Update function's max locals size
+    i64 max_offset = i64max(current_function->func.max_locals_size, cur_stack_offset);
+    current_function->func.max_locals_size = max_offset;
+
+    assert(cur_stack_offset >= 0);
+    assert(block_stack_count > 0);
+}
+
+void Node_add_child(Node *parent, Node *child)
+{
+    // TODO, use a vector
+    parent->block.children = realloc(parent->block.children, sizeof(Node *) * (parent->block.num_children + 1));
+    parent->block.children[parent->block.num_children] = child;
+    parent->block.num_children++;
+}
+
+Node *Node_new(NodeType type)
+{
+    Node *self = calloc(sizeof(Node), 1);
+    self->type = type;
+    return self;
+}
+
+Type parse_type(Lexer *lexer)
+{
+    Type type = {0};
+    Token token = Lexer_peek(lexer);
+    if (token.type == TOKEN_INT) {
+        type.type = TYPE_INT;
+        Lexer_next(lexer);
+    } else {
+        type.type = TYPE_NONE;
+    }
+
+    while (Lexer_peek(lexer).type == TOKEN_AMPERSAND) {
+        Lexer_next(lexer);
+        type.indirection++;
+    }
+
+    return type;
+}
+
+Node *parse_literal(Lexer *lexer)
+{
+    Node *node = Node_new(AST_LITERAL);
+    Token token = assert_token(Lexer_next(lexer), TOKEN_INTLIT);
+    node->literal.type = (Type) {.type = TYPE_INT};
+    node->literal.as_int = token.value.as_int;
+    return node;
+}
+
+Node *parse_expression(Lexer *);
+
+Node *parse_var_declaration(Lexer *lexer)
+{
+    Token token = assert_token(Lexer_next(lexer), TOKEN_LET);
+    // TODO: Reuse this for globals? Or maybe just make a new function?
+    if (!current_function || current_function->type != AST_FUNC)
+        die_location(token.loc, "Variable declaration outside of function");
+    
+    token = assert_token(Lexer_next(lexer), TOKEN_IDENTIFIER);
+    // NOTE: We don't allow shadowing of variables in the any blocks, 
+    //       this is by design since it's a common mistake.
+    if (find_local_variable(&token) != NULL)
+        die_location(token.loc, "Variable `%s` already declared", token.value.as_string);
+    
+    Node *node = Node_new(AST_VARDECL);
+    node->var_decl.var.name = token.value.as_string;
+
+    token = Lexer_next(lexer);
+    if (token.type != TOKEN_COLON)
+        die_location(token.loc, "Missing type specifier for variable `%s`", node->var_decl.var.name);
+    node->var_decl.var.type = parse_type(lexer);
+
+    add_variable_to_current_block(&node->var_decl.var);
+
+    token = Lexer_next(lexer);
+    if (token.type == TOKEN_ASSIGN) {
+        node->var_decl.value = parse_expression(lexer);
+        assert_token(Lexer_next(lexer), TOKEN_SEMICOLON);
+    } else {
+        assert_token(token, TOKEN_SEMICOLON);
+    }
+
+    return node;
+}
+
+Node *parse_function_call_args(Lexer *lexer, Node *func)
+{
+    Token identifier = assert_token(Lexer_next(lexer), TOKEN_IDENTIFIER);
+    Node *call = Node_new(AST_FUNCCALL);
+    call->call.func = func;
+    assert_token(Lexer_next(lexer), TOKEN_OPEN_PAREN);
+    Token token = Lexer_peek(lexer);
+
+    while (token.type != TOKEN_CLOSE_PAREN) {
+        Node *arg = parse_expression(lexer);
+
+        int new_size = call->call.num_args + 1;
+        call->call.args = realloc(call->call.args, sizeof(Node *) * new_size);
+        call->call.args[call->call.num_args++] = arg;
+        
+        if (new_size > func->func.num_args)
+            die_location(identifier.loc, "Too many arguments to function `%s`", func->func.name);
+
+        token = Lexer_peek(lexer);
+        if (token.type == TOKEN_COMMA) {
+            Lexer_next(lexer);
+            token = Lexer_peek(lexer);
+        }
+    }
+
+    if (call->call.num_args != func->func.num_args)
+        die_location(identifier.loc, "Too few arguments to function `%s`", func->func.name);
+
+    assert_token(Lexer_next(lexer), TOKEN_CLOSE_PAREN);
+    return call;
+}
+
+Node *parse_factor(Lexer *lexer)
+{
+    // TODO: Parse more complicated things
+    Token token = Lexer_peek(lexer);
+    Node *expr;
+    if (token.type == TOKEN_MINUS) {
+        Lexer_next(lexer);
+        expr = Node_new(OP_NEG);
+        expr->unary_expr = parse_factor(lexer);
+    } else if (token.type == TOKEN_TILDE) {
+        Lexer_next(lexer);
+        expr = Node_new(OP_BWINV);
+        expr->unary_expr = parse_factor(lexer);
+    } else if (token.type == TOKEN_EXCLAMATION) {
+        Lexer_next(lexer);
+        expr = Node_new(OP_NOT);
+        expr->unary_expr = parse_factor(lexer);
+    } else if (token.type == TOKEN_OPEN_PAREN) {
+        Lexer_next(lexer);
+        expr = parse_expression(lexer);
+        assert_token(Lexer_next(lexer), TOKEN_CLOSE_PAREN);
+    } else if (token.type == TOKEN_INTLIT) {
+        expr = parse_literal(lexer);
+    } else if (token.type == TOKEN_IDENTIFIER) {   
+        // TODO: Check for global variables when added
+
+        Variable *var = find_local_variable(&token); 
+        if (var != NULL) {
+            Lexer_next(lexer);
+            expr = Node_new(AST_VAR);
+            expr->variable = var;
+            return expr;
+        }
+        
+        Node *func = find_function_definition(&token);
+        if (func != NULL) {
+            return parse_function_call_args(lexer, func);
+        }
+
+        die_location(token.loc, "Unknown identifier `%s`", token.value.as_string);
+        expr = NULL;
+    } else {
+        die_location(token.loc, ": Expected token found in parse_factor: `%s`", token_type_to_str(token.type));
+        exit(1);
+    }
+    return expr;
+}
+
+#define BINOP_PARSER(next_parser, predicate)                                   \
+  Node *expr = next_parser(lexer);                                             \
+  Token token = Lexer_peek(lexer);                                             \
+  while (predicate(token.type)) {                                              \
+    Lexer_next(lexer);                                                         \
+    Node *op = Node_new(binary_token_to_op(token.type));                       \
+    Node *right = next_parser(lexer);                                          \
+    op->binary.left = expr;                                                    \
+    op->binary.right = right;                                                  \
+    expr = op;                                                                 \
+    token = Lexer_peek(lexer);                                                 \
+  }                                                                            \
+  return expr;
+
+bool is_term_token(TokenType type) { return type == TOKEN_STAR ||  type == TOKEN_SLASH ||  type == TOKEN_PERCENT; }
+Node *parse_term(Lexer *lexer) { BINOP_PARSER(parse_factor, is_term_token); }
+
+bool is_additive_token(TokenType type) { return type == TOKEN_PLUS || type == TOKEN_MINUS; }
+Node *parse_additive(Lexer *lexer) { BINOP_PARSER(parse_term, is_additive_token); }
+
+bool is_relational_token(TokenType type) { return type == TOKEN_LT || type == TOKEN_LEQ || type == TOKEN_GT || type == TOKEN_GEQ; }
+Node *parse_relational(Lexer *lexer) { BINOP_PARSER(parse_additive, is_relational_token); }
+
+bool is_equality_token(TokenType type) { return type == TOKEN_EQ || type == TOKEN_NEQ; }
+Node *parse_equality(Lexer *lexer) { BINOP_PARSER(parse_relational, is_equality_token); }
+
+bool is_logical_and_token(TokenType type) { return type == TOKEN_AND; }
+Node *parse_logical_and(Lexer *lexer) { BINOP_PARSER(parse_equality, is_logical_and_token); }
+
+bool is_logical_or_token(TokenType type) { return type == TOKEN_OR; }
+Node *parse_logical_or(Lexer *lexer) { BINOP_PARSER(parse_logical_and, is_logical_or_token); }
+
+Node *parse_conditional_exp(Lexer *lexer)
+{
+    Node *expr = parse_logical_or(lexer);
+    Token token = Lexer_peek(lexer);
+    if (token.type == TOKEN_QUESTION) {
+        Lexer_next(lexer);
+        Node *then_expr = parse_expression(lexer);
+        assert_token(Lexer_next(lexer), TOKEN_COLON);
+        Node *else_expr = parse_expression(lexer);
+        Node *conditional = Node_new(AST_CONDITIONAL);
+        conditional->conditional.cond = expr;
+        conditional->conditional.do_then = then_expr;
+        conditional->conditional.do_else = else_expr;
+        expr = conditional;
+    }
+    return expr;
+}
+
+Node *parse_expression(Lexer *lexer)
+{
+    Node *node = parse_conditional_exp(lexer);
+    // FIXME: This is a hack to handle assignment expressions
+    //        and can probably be done properly.
+    if (node->type == AST_VAR) {
+        Token token = Lexer_peek(lexer);
+        if (token.type == TOKEN_ASSIGN) {
+            Lexer_next(lexer);
+            Variable *var = node->variable;
+            node->type = OP_ASSIGN;
+            node->assign.var = var;
+            node->assign.value = parse_expression(lexer);
+        }
+    }
+    return node;
+}
+
+Node *parse_block(Lexer *lexer);
+
+Node *parse_statement(Lexer *lexer)
+{
+    Node *node;
+    Token token = Lexer_peek(lexer);
+
+    if (token.type == TOKEN_RETURN) {
+        assert_token(Lexer_next(lexer), TOKEN_RETURN);
+        node = Node_new(AST_RETURN);
+        node->unary_expr = parse_expression(lexer);
+        assert_token(Lexer_next(lexer), TOKEN_SEMICOLON);
+    } else if (token.type == TOKEN_IF) {
+        Lexer_next(lexer);
+        node = Node_new(AST_IF);
+        assert_token(Lexer_next(lexer), TOKEN_OPEN_PAREN);
+        node->conditional.cond = parse_expression(lexer);
+        assert_token(Lexer_next(lexer), TOKEN_CLOSE_PAREN);
+        // TODO: Allow blocks in here once implemented, currently
+        //       we can onle have a single statement in the if/else
+        node->conditional.do_then = parse_statement(lexer);
+        token = Lexer_peek(lexer);
+        if (token.type == TOKEN_ELSE) {
+            Lexer_next(lexer);
+            node->conditional.do_else = parse_statement(lexer);
+        }
+    } else if (token.type == TOKEN_WHILE) {
+        Lexer_next(lexer);
+        node = Node_new(AST_WHILE);
+        assert_token(Lexer_next(lexer), TOKEN_OPEN_PAREN);
+        node->loop.cond = parse_expression(lexer);
+        assert_token(Lexer_next(lexer), TOKEN_CLOSE_PAREN);
+        node->loop.body = parse_statement(lexer);
+    }  else if (token.type == TOKEN_FOR) {
+        Lexer_next(lexer);
+        node = Node_new(AST_FOR);
+        assert_token(Lexer_next(lexer), TOKEN_OPEN_PAREN);
+        
+        // All of the expressions in the for loop are optional
+
+        // TODO: Allow this to be a declaration, need to inject
+        //       the variable into the symbol table for the block
+        if (Lexer_peek(lexer).type != TOKEN_SEMICOLON)
+            node->loop.init = parse_expression(lexer);
+        assert_token(Lexer_next(lexer), TOKEN_SEMICOLON);
+
+        if (Lexer_peek(lexer).type != TOKEN_SEMICOLON)
+            node->loop.cond = parse_expression(lexer);
+        assert_token(Lexer_next(lexer), TOKEN_SEMICOLON);
+
+        if (Lexer_peek(lexer).type != TOKEN_CLOSE_PAREN)
+            node->loop.step = parse_expression(lexer);
+        assert_token(Lexer_next(lexer), TOKEN_CLOSE_PAREN);
+
+        node->loop.body = parse_statement(lexer);
+    } else if (token.type == TOKEN_OPEN_BRACE) {
+        node = parse_block(lexer);
+    } else {
+        // Default to trying to handle it as an expression
+        node = parse_expression(lexer);
+        assert_token(Lexer_next(lexer), TOKEN_SEMICOLON);
+    }
+
+    return node;
+}
+
+Node *parse_block(Lexer *lexer)
+{
+    assert_token(Lexer_next(lexer), TOKEN_OPEN_BRACE);
+
+    Node *block = Node_new(AST_BLOCK);
+    Token token = Lexer_peek(lexer);
+
+    block_stack_push(block);
+
+    while (token.type != TOKEN_CLOSE_BRACE) {
+        Node *block_item;
+        if (token.type == TOKEN_LET) {
+            block_item = parse_var_declaration(lexer);
+        } else {
+            // Default to a statement
+            block_item = parse_statement(lexer);
+        }
+        Node_add_child(block, block_item);
+        token = Lexer_peek(lexer);
+    }
+
+    block_stack_pop();
+
+    assert_token(Lexer_next(lexer), TOKEN_CLOSE_BRACE);
+    return block;
+}
+
+void push_new_function(Node *func)
+{
+    assert(func->type == AST_FUNC);
+    assert(function_count < MAX_FUNCTION_COUNT);
+    all_functions[function_count++] = func;
+    current_function = func;
+}
+
+void parse_func_args(Lexer *lexer, Node *func)
+{
+    assert_token(Lexer_next(lexer), TOKEN_OPEN_PAREN);
+    Token token = Lexer_peek(lexer);
+    while (token.type != TOKEN_CLOSE_PAREN) {
+        token = assert_token(Lexer_next(lexer), TOKEN_IDENTIFIER);
+        // TODO: Check for shadowing with globals
+        assert_token(Lexer_next(lexer), TOKEN_COLON);
+        Type type = parse_type(lexer);    
+
+        i64 new_count = func->func.num_args + 1;
+        func->func.args = realloc(func->func.args, sizeof(Variable) * new_count);
+        Variable *var = &func->func.args[func->func.num_args++];
+        var->name = token.value.as_string;
+        var->type = type;
+
+        token = Lexer_peek(lexer);
+        if (token.type == TOKEN_COMMA) {
+            Lexer_next(lexer);
+            token = Lexer_peek(lexer);
+        }
+    }
+    assert_token(Lexer_next(lexer), TOKEN_CLOSE_PAREN);
+
+    // Set the offsets for the arguments
+    
+    // IMPORTANT: We want to skip the saved ret_addr+old_rbp that we
+    //            pushed on the stack. Each of these is 8 bytes.
+    int offset = -16; 
+    for (int i = 0; i < func->func.num_args; i++) {
+        Variable *var = &func->func.args[i];
+        var->offset = offset;
+        // TODO: Compute this for different types
+        int var_size = 8;
+        offset -= var_size;
+    }
+}
+
+Node *parse_func(Lexer *lexer)
+{
+    Token token;
+    token = assert_token(Lexer_next(lexer), TOKEN_FN);
+
+    Node *func = Node_new(AST_FUNC);
+    push_new_function(func);
+
+    token = assert_token(Lexer_next(lexer), TOKEN_IDENTIFIER);
+    func->func.name = token.value.as_string;
+    parse_func_args(lexer, func);
+
+    token = Lexer_peek(lexer);
+    if (token.type == TOKEN_COLON) {
+        // TODO: Parse all return types
+        assert_token(Lexer_next(lexer), TOKEN_COLON);
+        func->func.return_type = parse_type(lexer);
+    } else {
+        // No return type, void fn.
+        func->func.return_type = (Type){.type = TYPE_NONE};
+    }
+
+    // Make sure there's no funny business with the stack offset
+    assert(cur_stack_offset == 0);
+    assert(block_stack_count == 0);
+    func->func.body = parse_block(lexer);
+    assert(block_stack_count == 0);
+    assert(cur_stack_offset == 0);
+
+    return func;
+}
+
+Node *parse_program(Lexer *lexer)
+{
+    Node *program = Node_new(AST_PROGRAM);
+    Token token;
+    while ((token = Lexer_peek(lexer)).type != TOKEN_EOF) {
+        if (token.type == TOKEN_FN) {
+            Node *func = parse_func(lexer);
+            Node_add_child(program, func);
+        } else {
+            die_location(token.loc, "Unexpected token in parse_program: `%s`\n", token_type_to_str(token.type));
+            exit(1);
+            break;
+        }
+    }
+    return program;
+}
\ No newline at end of file