emitbc.c

#include <unistd.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>

#include "misc.h"
#include "mpconfig.h"
#include "qstr.h"
#include "lexer.h"
#include "parse.h"
#include "scope.h"
#include "runtime0.h"
#include "emit.h"
#include "bc0.h"

struct _emit_t {
    pass_kind_t pass;
    int stack_size;
    bool last_emit_was_return_value;

    scope_t *scope;

    uint last_source_line_offset;
    uint last_source_line;

    uint max_num_labels;
    uint *label_offsets;

    uint code_info_offset;
    uint code_info_size;
    uint byte_code_offset;
    uint byte_code_size;
    byte *code_base; // stores both byte code and code info
    byte dummy_data[8];
};

emit_t *emit_bc_new(uint max_num_labels) {
    emit_t *emit = m_new0(emit_t, 1);
    emit->max_num_labels = max_num_labels;
    emit->label_offsets = m_new(uint, emit->max_num_labels);
    return emit;
}

void emit_bc_free(emit_t *emit) {
    m_del(uint, emit->label_offsets, emit->max_num_labels);
    m_del_obj(emit_t, emit);
}

// all functions must go through this one to emit code info
static byte* emit_get_cur_to_write_code_info(emit_t* emit, int num_bytes_to_write) {
    //printf("emit %d\n", num_bytes_to_write);
    if (emit->pass < PASS_3) {
        emit->code_info_offset += num_bytes_to_write;
        return emit->dummy_data;
    } else {
        assert(emit->code_info_offset + num_bytes_to_write <= emit->code_info_size);
        byte *c = emit->code_base + emit->code_info_offset;
        emit->code_info_offset += num_bytes_to_write;
        return c;
    }
}

static void emit_write_code_info_qstr(emit_t* emit, qstr qstr) {
    byte* c = emit_get_cur_to_write_code_info(emit, 4);
    // TODO variable length encoding for qstr
    c[0] = qstr & 0xff;
    c[1] = (qstr >> 8) & 0xff;
    c[2] = (qstr >> 16) & 0xff;