path: root/main.c

#include <stdio.h>
#include <stdint.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <assert.h>

#include "lex.h"
#include "arena.h"
#include "dynarr.h"
#include "strio.h"
#include "ir.h"
#include "peephole.h"
#include "proc.h"

int no_opt = 0;

typedef struct {
	DYNARR(Proc) procs;
} Unit;

void unit_init(Unit *u) {
	(void)u;
}

void unit_free(Unit *u) {
	for (int i = 0; i < u->procs.len; i++) {
		proc_free(&u->procs.data[i]);
	}
	free(u->procs.data);
}

/* parsing */

Node *parse_expr(Lexer *l, Proc *p, Type *twant);

/* TODO: eliminate unused if-else statements at the end of compilation
 * they don't get pruned out by peephole optimizations if there are phi
 * nodes that are connected to keepalive (due to still being in scope).
 * so probably this will have to be done in a separate step after the
 * graph has been generated.
 */

Node *ctrl(Graph *p, Node *n) {
	if (!n) {
		p->ctrl = node_new_lit(p, (Value) {
			.type = { .lvl = T_XCTRL, .t = T_NONE }
		});
		return NULL;
	}
	p->ctrl = n;
	return n;
}

void parse_return(Lexer *l, Proc *p) {
	lex_next(l);
	Node *n;
	Graph *g = &p->graph;
	if (p->ret_type.t == T_NONE) {
		n = node_new(g, N_RETURN, g->ctrl);
	} else {
		Node *e = parse_expr(l, p, &p->ret_type);
		n = node_new(g, N_RETURN, g->ctrl, e);
	}
	n = node_peephole(n, g, l);
	if (n->type.lvl != T_XCTRL) {
		node_add(g, n, g->stop);
	}
	ctrl(g, n);
	ctrl(g, NULL);
}

Type parse_type(Lexer *l, Proc *proc) {
	(void)proc;
	Type t = { .lvl = T_BOT };
	if (l->tok == TOK_DEREF) {
		lex_next(l);
		t.t = T_PTR;
		t.next = new(&proc->perm, Type);
		*t.next = parse_type(l, proc);
		return t;
	}
	lex_expected(l, TM_IDENT);
	if (l->tok == TOK_IDENT) {
		if (str_eql(l->ident, S("i64"))) {
			t.t = T_INT;
		} else if (str_eql(l->ident, S("bool"))) {
			t.t = T_BOOL;
		} else {
			lex_error(l, LE_ERROR, S("unknown type"));
		}
	}
	lex_next(l);
	return t;
}

void parse_let(Lexer *l, Proc *p) {
	Graph *g = &p->graph;
recurse:
	lex_expect(l, TM_IDENT);
	Str name = l->ident;
	LexSpan pos = l->pos;
	lex_next(l);
	Node *rhs = NULL;
	Type t = { .t = T_NONE };
	if (l->tok != TOK_EQL) {
		t = parse_type(l, p);
		if (l->tok != TOK_EQL) {
			rhs = node_new(g, N_UNINIT, g->start);
			rhs->type = t;
		}
	}
	if (l->tok == TOK_EQL) {
		lex_next(l);
		rhs = parse_expr(l, p, t.t == T_NONE ? NULL : &t);
	}
	NameBinding *b = scope_bind(&p->scope, name, rhs, pos, g);
	if (b) {
		lex_error_at(l, pos, LE_WARN, S("shadowing previous declaration"));
		lex_error_at(l, b->src_pos, LE_WARN, S("declared here"));
	}
	/* TODO: isn't this just a do while loop */
	if (l->tok == TOK_COMMA) goto recurse;
}

void parse_stmt(Lexer *l, Proc *p);

/* TODO: return node from this! */
void parse_block(Lexer *l, Proc *p, ScopeNameList *nl) {
	Graph *g = &p->graph;
	lex_next(l);
	arena_reset(&p->scratch);
	scope_push(&p->scope);
	while (l->tok != TOK_RBRACE) {
		lex_expected_not(l, TM_EOF);
		parse_stmt(l, p);
	}
	if (nl) {
		scope_collect(&p->scope, g, nl, &p->scratch);
	}
	scope_pop(&p->scope, g);
	lex_expected(l, TM_RBRACE);
	lex_next(l);
}

void parse_assign(Lexer *l, Proc *p) {
	Str name = l->ident;
	LexSpan pos = l->pos;
	lex_expect(l, TM_ASSIGN);
	lex_next(l);
	NameBinding *b = scope_find(&p->scope, name);
	if (!b) {
		lex_error_at(l, pos, LE_ERROR, S("undeclared identifier"));
	}
	Node *e = parse_expr(l, p, &b->node->type);
	if (node_uninit(e)) {
		lex_error_at(l, e->src_pos, LE_ERROR,
				str_fmt(&p->scratch, "uninitialized %S",
					type_desc(&e->type, &p->scratch)));
	} else if (node_maybe_uninit(e)) {
		lex_error_at(l, e->src_pos, LE_WARN,
				str_fmt(&p->scratch, "possibly uninitialized %S",
					type_desc(&e->type, &p->scratch)));
	}
	scope_update(b, e, &p->graph);
}

/* TODO: Implement a better system for this.
 *
 * Something like:
 *
 * 	ScopeChangeList chg_true = {0}, chg_false = {0};
 * 	scope_track_changes(&p->scope, &chg_true, p, scratch);
 * 	parse_block(l, p);
 * 	scope_rewind_changes(&p->scope, &chg_true, p);
 *	scope_track_changes(&p->scope, &chg_false, p, scratch);
 * 	parse_block(l, p);
 * 	scope_merge_changes(&p->scope, &chg_true, &chg_false, region, p);
 *
 * We put a flag in Scope somewhere that marks where it's tracking changes to,
 * then have scope_update() look up the name binding being changed in the change
 * list;  if present, update value to the new node.  If not, create it with
 * orig set to the previous value of the name binding, and value to the new node.
 * Since we're only tracking _changes_, there should be some way to make sure that
 * newly created let-bindings after tracking starts aren't stored in the list.
 * Maybe give NameBindings an index, note the index of the latest binding at the
 * time scope_track_changes() is called, ignore any larger than it.
 *
 * Take care with making sure changes remain attached to keepalive --- rewind
 * doesn't remove the new values, since it's just to revert temporarily.
 *
 * Also, probably should have a scratch arena for this sort of throwaway parsing
 * data, instead of putting stuff in the procedure graph arena.  It can be reset
 * after each statement.
 *
 * Also also, switch scopes from a linked list to something a bit faster, like
 * a simple arena-backed hash trie.
 *
 */

void merge_scope(Lexer *l, Proc *p, Node *region, ScopeNameList *before, ScopeNameList *ntrue, ScopeNameList *nfalse) {
	Graph *g = &p->graph;
	for (int i = 0; i < before->len; i++) {
		int j, k;
		ScopeName *b4 = &before->data[i];
		for (j = 0; j < ntrue->len && !str_eql(ntrue->data[j].name, b4->name); j++);
		for (k = 0; k < nfalse->len && !str_eql(nfalse->data[k].name, b4->name); k++);
		ScopeName *yes = j < ntrue->len ? &ntrue->data[j] : NULL;
		ScopeName *no = k < nfalse->len ? &nfalse->data[k] : NULL;
		if (!yes && !no) continue; /* no change */
		Node *phi;
		if (!no) {
			if (yes->node == b4->node) continue;
			phi = node_new(g, N_PHI, region, yes->node, b4->node);
		} else if (!yes) {
			if (no->node == b4->node) continue;
			phi = node_new(g, N_PHI, region, b4->node, no->node);
		} else {
			if (yes->node == b4->node && no->node == b4->node) continue;
			phi = node_new(g, N_PHI, region, yes->node, no->node);
		}
		phi = node_peephole(phi, g, l);
		NameBinding *b = scope_find(&p->scope, b4->name);
		assert(b);
		scope_update(b, phi, g);
	}
}

/* TODO: find out a way to encode known relations between nodes, based on the
 * conditional, within the body of an if statement --- e.g., for a statement
 *
 * if a < 5 {
 * 	if a < 10 {
 * 		foo()
 * 	}
 * } else {
 * 	if a > 3 {
 * 		bar()
 * 	}
 * }
 *
 * we should be able to infer that the second condition is always true, because
 * it's only reachable if a < 5, and 5 < 10.  conversely, in the else branch,
 * we know that a >= 5, and can use that to make assumptions on comparisons
 * made there too!
 *
 */

void parse_if(Lexer *l, Proc *p) {
	Graph *g = &p->graph;
	lex_next(l);
	Node *cond = parse_expr(l, p, &(Type) { .t = T_BOOL });
	Node *ctrl_if = NULL, *ctrl_else = NULL;
	Node *if_node = node_new(g, N_IF_ELSE, g->ctrl, cond);
	if_node->val = (Value) {
		.type = { .lvl = T_TOP, .t = T_TUPLE },
		.tuple = { 0 }
	};
	ZDA_PUSH(g->pool->arena, &if_node->val.tuple, (Value) { .type = { .lvl = T_CTRL, .t = T_NONE } });
	ZDA_PUSH(g->pool->arena, &if_node->val.tuple, (Value) { .type = { .lvl = T_CTRL, .t = T_NONE } });
	if_node = node_peephole(if_node, g, l);
	node_add(g, if_node, g->keepalive);
	Node *if_true = node_new(g, N_PROJ, if_node);
	Node *if_false = node_new(g, N_PROJ, if_node);
	if_true->val.i = 0;
	if_false->val.i = 1;
	if_true = node_peephole(if_true, g, l);
	if_false = node_peephole(if_false, g, l);
	node_remove(g, if_node, g->keepalive);
	assert(if_true->in.len > 0);
	assert(if_false->in.len > 0);
	node_add(g, if_true, g->keepalive);
	node_add(g, if_false, g->keepalive);
	ScopeNameList scope_before = { 0 }, scope_true = { 0 }, scope_false = { 0 };
	scope_collect(&p->scope, g, &scope_before, &p->scratch);
	if (cond->type.lvl == T_CONST) {
		if (cond->val.i) if_false->type.lvl = T_XCTRL;
		else if_true->type.lvl = T_XCTRL;
	}
	ctrl(g, if_true);
	lex_expected(l, TM_LBRACE);
	int pos = l->pos.ofs;
	parse_block(l, p, &scope_true);
	if_true->src_pos = (LexSpan) { .ofs = pos, .n = l->pos.ofs - pos };
	ctrl_if = g->ctrl;
	node_add(g, ctrl_if, g->keepalive);
	if (l->tok == TOK_ELSE) {
		for (int i = 0; i < scope_before.len; i++) {
			scope_update(scope_find(&p->scope, scope_before.data[i].name), scope_before.data[i].node, g);
		}
		ctrl(g, if_false);
		lex_expect(l, TM_LBRACE);
		pos = l->pos.ofs;
		parse_block(l, p, &scope_false);
		if_false->src_pos = (LexSpan) { .ofs = pos, .n = l->pos.ofs - pos };
		ctrl_else = g->ctrl;
		node_add(g, ctrl_else, g->keepalive);
	}
	Node *region;
	if (ctrl_else) {
		assert(ctrl_if);
		assert(ctrl_else);
		region = node_new(g, N_REGION, ctrl_if, ctrl_else);
		node_add_out(g, region, g->keepalive);
		node_remove(g, ctrl_if, g->keepalive);
		node_remove(g, ctrl_else, g->keepalive);
	} else {
		assert(ctrl_if);
		assert(if_false);
		region = node_new(g, N_REGION, ctrl_if, if_false);
		node_add_out(g, region, g->keepalive);
		node_remove(g, ctrl_if, g->keepalive);
		assert(if_true->refs > 0);
		assert(if_false->refs > 0);
	}
	ctrl(g, region);
	node_remove(g, if_true, g->keepalive);
	node_remove(g, if_false, g->keepalive);
	assert(g->ctrl->in.len > 0);
	assert(region->in.data[0]);
	assert(region->in.data[1]);
	merge_scope(l, p, region, &scope_before, &scope_true, &scope_false);
	scope_uncollect(&p->scope, g, &scope_true);
	scope_uncollect(&p->scope, g, &scope_false);
	scope_uncollect(&p->scope, g, &scope_before);
	node_del_out(region, g->keepalive);
	/* make sure we're not orphaning any phi nodes*/
	if (g->ctrl->out.len < 1) {
		ctrl(g, node_peephole(g->ctrl, g, l));
	}
}

void parse_stmt(Lexer *l, Proc *p) {
	/* TODO */
	(void)l;
	switch (l->tok) {
	case TOK_RETURN:
		parse_return(l, p);
		break;
	case TOK_LET:
		parse_let(l, p);
		break;
	case TOK_LBRACE:
		parse_block(l, p, NULL);
		break;
	case TOK_IDENT:
		parse_assign(l, p);
		break;
	case TOK_IF:
		parse_if(l, p);
		break;
	default:
		lex_expected(l, TM_RBRACE);
		break;
	}
}

void parse_args_list(Lexer *l, Proc *proc) {
	Node *start = proc->graph.start;
	Graph *g = &proc->graph;
	int i = 0;
	struct {
		Str name;
		LexSpan pos;
	} idbuf[32];
	int id = 0;
	while (l->tok != TOK_RPAREN && l->tok != TOK_EOF) {
		lex_expect(l, TM_IDENT);
		if (id == sizeof idbuf / sizeof *idbuf) {
			lex_error(l, LE_ERROR, S("too many arguments without specifying a type"));
			return;
		}
		idbuf[id].name = l->ident;
		idbuf[id].pos = l->pos;
		id++;
		lex_next(l);
		if (l->tok == TOK_COMMA) continue;
		Value v = (Value) { .type = parse_type(l, proc) };
		lex_expected(l, TM_RPAREN | TM_COMMA);
		for (int j = 0; j < id; j++) {
			Node *proj = node_new(g, N_PROJ, start);
			proj->type = v.type;
			proj->val.i = i++;
			ZDA_PUSH(&proc->perm, &start->val.tuple, v);
			scope_bind(&proc->scope, idbuf[j].name, proj, idbuf[j].pos, g);
		}
		id = 0;
	}
	lex_expected(l, TM_RPAREN);
	lex_next(l);
}

Node *find_return(Node *n) {
	if (n->op == N_RETURN) return n;
	for (int i = 0; i < n->out.len; i++) {
		Node *r = find_return(n->out.data[i]);
		if (r) return r;
	}
	return NULL;
}

void proc_opt_fwd(Proc *p, Lexer *l, Node *n) {
	Graph *g = &p->graph;
	if (n->walked == 2) return;
	n->walked = 2;
	switch (n->op) {
	case N_START:
		for (int i = 0; i < n->out.len; i++) {
			proc_opt_fwd(p, l, n->out.data[i]);
		}
		break;
	case N_IF_ELSE:
		if (n->out.len < 2) {
			//lex_error_at(l, n->src_pos, LE_ERROR, S("not all codepaths return"));
		}
		for (int i = 0; i < n->out.len; i++) {
			Node *r = find_return(n->out.data[i]);
			if (!r) {
				lex_error_at(l, n->out.data[i]->src_pos, LE_ERROR, S("not all codepaths return"));
			}
			proc_opt_fwd(p, l, n->out.data[i]);
		}
		break;
	case N_PROJ:
		proc_opt_fwd(p, l, n->out.data[0]);
		break;
	case N_REGION:
		/* cull empty if else */
		if (n->out.len == 1 && n->in.len == 2
				&& IN(n,0)->op == N_PROJ
				&& IN(n,1)->op == N_PROJ
				&& CTRL(IN(n,0)) == CTRL(IN(n,1))
				&& CTRL(IN(n,0))->op == N_IF_ELSE) {
			assert(n->out.data[0]->op != N_PHI);
			assert(n->out.data[0]->in.data[0] == n);
			Node *new_ctrl = CTRL(CTRL(CTRL(n)));
			Node *out = n->out.data[0];
			node_set_in(g, out, 0, new_ctrl);
			proc_opt_fwd(p, l, new_ctrl);
			return;
		}
		for (int i = 0; i < n->out.len; i++) {
			if (n->out.data[i]->op != N_PHI) {
				proc_opt_fwd(p, l, n->out.data[i]);
			}
		}
		break;
	default:
		break;
	}
}

void proc_opt(Proc *p, Lexer *l) {
	Graph *g = &p->graph;
	if (g->stop->in.len == 0) {
		if (p->ret_type.t != T_NONE) {
			lex_error(l, LE_ERROR, str_fmt(&p->scratch, "no return statement in function expecting %S", type_desc(&p->ret_type, &p->scratch)));
		}
	}
	for (int i = 0; i < g->start->out.len; i++) {
		Node *n = g->start->out.data[i];
		if (n->op == N_LIT && n->out.len < 1) {
			node_kill(n, g);
			i--;
		}
	}
	proc_opt_fwd(p, l, g->start);
}

Proc *parse_proc(Lexer *l, Unit *u) {
	int has_ret = l->tok == TOK_FUNC;
	DA_FIT(&u->procs, u->procs.len + 1);
	Proc *proc = &u->procs.data[u->procs.len++];
	lex_expect(l, TM_IDENT);
	proc_init(proc, l->ident);
	scope_push(&proc->scope);
	lex_next(l);
	if (l->tok == TOK_LPAREN) {
		parse_args_list(l, proc);
	}
	if (has_ret) {
		proc->ret_type = parse_type(l, proc);
	} else {
		proc->ret_type = (Type) { .lvl = T_BOT, .t = T_NONE };
	}
	lex_expected(l, TM_LBRACE);
	lex_next(l);
	while (l->tok != TOK_RBRACE) {
		lex_expected_not(l, TM_EOF);
		parse_stmt(l, proc);
	}
	scope_pop(&proc->scope, &proc->graph);
	lex_expected(l, TM_RBRACE);
	lex_next(l);
	proc_opt(proc, l);
	return proc;
}

void uninit_check(Lexer *l, Node *n, LexSpan pos) {
	if (node_uninit(n)) {
		lex_error_at(l, pos, LE_ERROR,
				str_fmt(&l->arena, "uninitialized %S",
					type_desc(&n->type, &l->arena)));
	} else if (node_maybe_uninit(n)) {
		lex_error_at(l, pos, LE_WARN,
				str_fmt(&l->arena, "possibly uninitialized %S",
					type_desc(&n->type, &l->arena)));
	}
}

Node *parse_term(Lexer *l, Proc *p, Type *twant) {
	(void)twant; /* to be used for .ENUM_TYPE and stuff */
	Node *node = NULL;
	NodeType op_after = N_START;
	Graph *g = &p->graph;
	if (TMASK(l->tok) & (TM_MINUS | TM_PLUS | TM_NOT)) {
		Token t = l->tok;
		lex_next(l);
		node = parse_term(l, p, twant);
		NodeType post_op = N_START;
		switch (t) {
		case TOK_MINUS: post_op = N_OP_NEG; break;
		case TOK_NOT: post_op = N_OP_NOT; break;
		default: return node;
		}
		if (post_op == N_START) return node;
		return node_peephole(node_new(g, post_op, NULL, node), g, l);
	}
	if (l->tok == TOK_LPAREN) {
		lex_next(l);
		node = parse_expr(l, p, NULL);
		lex_expected(l, TM_RPAREN);
		lex_next(l);
		node->src_pos.ofs--;
		node->src_pos.n += 2;
	} else if (l->tok == TOK_IDENT) {
		NameBinding *b = scope_find(&p->scope, l->ident);
		if (b) {
			node = b->node;
		} else {
			lex_error(l, LE_ERROR, S("undeclared identifier"));
		}
		uninit_check(l, node, l->pos);
		lex_next(l);
	} else if (TMASK(l->tok) & (TM_TRUE | TM_FALSE)) {
		node = node_new_lit_bool(g, l->tok == TOK_TRUE);
		lex_next(l);
	} else {
		lex_expected(l, TM_LIT_NUM);
		int64_t val = 0;
		for (int i = 0; i < l->ident.n; i++) {
			if (!(l->ident.s[i] >= '0' && l->ident.s[i] <= '9')) {
				lex_error(l, LE_ERROR, S("not a digit"));
				break;
			}
			val = (val * 10) + (l->ident.s[i] - '0');
		}
		node = node_new_lit_i64(g, val);
		node->src_pos = l->pos;
		lex_next(l);
	}
	if (op_after != N_START) {
		node = node_new(g, op_after, NULL, node_peephole(node, g, l));
	}
	return node_peephole(node, g, l);
}

NodeType tok_to_bin_op(Token t) {
	switch (t) {
	case TOK_PLUS: return N_OP_ADD; break;
	case TOK_MINUS: return N_OP_SUB; break;
	case TOK_ASTERISK: return N_OP_MUL; break;
	case TOK_SLASH: return N_OP_DIV; break;
	case TOK_NOT: return N_OP_NOT; break;
	case TOK_AND: return N_OP_AND; break;
	case TOK_OR: return N_OP_OR; break;
	case TOK_XOR: return N_OP_XOR; break;
	case TOK_SHL: return N_OP_SHL; break;
	case TOK_SHR: return N_OP_SHR; break;
	case TOK_EQL: return N_CMP_EQL; break;
	case TOK_NEQ: return N_CMP_NEQ; break;
	case TOK_LES: return N_CMP_LES; break;
	case TOK_GTR: return N_CMP_GTR; break;
	case TOK_LTE: return N_CMP_LTE; break;
	case TOK_GTE: return N_CMP_GTE; break;
	default: return N_START; break;
	}
}

/* TODO: operator precedence would be kinda nice actually, sad to say */
Node *parse_expr(Lexer *l, Proc *p, Type *twant) {
	LexSpan pos = l->pos;
	Graph *g = &p->graph;
	Node *lhs = parse_term(l, p, twant);
	NodeType nt = tok_to_bin_op(l->tok);;
	if (lhs->refs <= 0) lex_error(l, LE_ERROR, S("dead lhs"));
	assert(lhs->refs > 0);
	if (nt != N_START) {
		lex_next(l);
		/* necessary because if lhs is a deduplicated literal, it may be an input to rhs
		 * and therefore culled by peephole optimizations */
		Node *rhs;
		NODE_KEEP(g, lhs, {
			rhs = parse_expr(l, p, &lhs->type);
		});
		lhs = node_peephole(node_new(g, nt, NULL, lhs, rhs), g, l);
	}
	lhs->src_pos = (LexSpan) { pos.ofs, l->pos.ofs - pos.ofs };
	if (twant) type_expected(twant, lhs, l);
	return lhs;
}

void parse_toplevel(Lexer *l, Unit *u) {
	switch (l->tok) {
	case TOK_PROC:
	case TOK_FUNC:
		parse_proc(l, u);
		break;
	default:
		lex_expected(l, TM_PROC | TM_FUNC);
		break;
	}
}


void unit_print(Unit *u);
void parse_unit(Lexer *l) {
	Unit u = { 0 };
	unit_init(&u);
	while (l->tok != TOK_EOF) {
		parse_toplevel(l, &u);
	}
	unit_print(&u);
	unit_free(&u);
}

/* graph output */

/* TODO: Print at every stage of graph compilation and generate a frame for
 * each, so problems can be debugged visually as they occur.
 */

void node_print(Node *n, Proc *p) {
	if (n->walked == 1) return;
	n->walked = 1;
	if (n->op == N_START) {
		Str s = S("");
		int c = n->val.tuple.len;
		Value *v = n->val.tuple.data;
		for (int i = 0; i < c; i++) {
			if (i > 0) str_cat(&s, S(", "), &p->scratch);
			str_cat(&s, type_desc(&v[i].type, &p->scratch), &p->scratch);
		}
		printf("\t%d [label=\"start(%.*s)\"]", n->id, (int)s.n, s.s);
	} else if (n->op == N_LIT) {
		switch (n->type.t) {
		case T_INT:
			printf("\t%d [label=\"%ld\"]", n->id, n->val.i);
			break;
		case T_BOOL:
			printf("\t%d [label=\"%s\"]", n->id, n->val.i ? "true" : "false");
			break;
		case T_NONE:
			if (n->type.lvl == T_XCTRL) {
				printf("\t%d [label=\"~ctrl\"]", n->id);
				break;
			}
			/* fallthrough */
		default:
			printf("\t%d [label=\"literal %d\"]", n->id, n->id);
			break;
		}
	} else if (n->op == N_PROJ) {
		Str d = type_desc(&n->in.data[0]->val.tuple.data[n->val.i].type, &p->scratch);
		printf("\t%d [label=\"%.*s(%ld)\", shape=record]", n->id, (int)d.n, d.s, n->val.i);
	} else if (n->op == N_UNINIT) {
		Str s = type_desc(&n->type, &p->scratch);
		printf("\t%d [label=\"uninitialized %.*s\", shape=record]", n->id, (int)s.n, s.s);
	} else {
		printf("\t%d [label=\"%s\", shape=record]", n->id, node_type_name(n->op));
	}
	printf("\n");
	for (int i = 0; i < n->out.len; i++) {
		Node *o = n->out.data[i];
		if (o->op == N_LIT) {
			printf("\t%d -> %d [style=dashed]\n", n->id, o->id);
		} else {
			int j;
			for (j = 0; j < o->in.len && o->in.data[j] != n; j++);
			if (j == 0) {
				printf("\t%d -> %d [color=red,headlabel=%d]\n", n->id, o->id, j);
			} else {
				printf("\t%d -> %d [headlabel=%d]\n", n->id, o->id, j);
			}
		}
	}
	for (int i = 0; i < n->out.len; i++) {
		node_print(n->out.data[i], p);
	}
}

void proc_print(Proc *p) {
	Graph *g = &p->graph;
	if (g->start) {
		Str d = type_desc(&p->ret_type, &p->scratch);
		printf("\t\"%.*s %.*s\" -> %d\n", (int)p->name.n, p->name.s, (int)d.n, d.s, g->start->id);
		node_print(g->start, p);
		if (no_opt) {
			for (NameBinding *b = p->scope.free_bind; b; b = b->prev) {
				uint64_t id = (uintptr_t)b->node;
				printf("\t\t%lu [label=\"%.*s\",shape=none,fontcolor=blue]\n", id, (int)b->name.n, b->name.s);
				printf("\t\t%lu -> %d [arrowhead=none,style=dotted,color=blue]\n", id, b->node->id);
			}
		}
	}
}

void unit_print(Unit *u) {
	puts("digraph {");
	for (int i = 0; i < u->procs.len; i++) {
		proc_print(&u->procs.data[i]);
	}
	puts("}");
}

/* main */

int main(int argc, const char **argv) {
	if (argc != 2) {
		fprintf(stderr, "Usage: %s FILE\n", argv[0]);
		return 1;
	}
	Lexer l = { 0 };
	lex_start(&l, argv[1]);
	parse_unit(&l);
	lex_free(&l);
	return 0;
}