Add first encoding pass

First pass collects all the symbols and interprets number and register
tokens into usable data for the later passes.

src/encoder/encoder.c

@@ -0,0 +1,209 @@
+#include "encoder.h"
+#include "../data/opcodes.h"
+#include "symbols.h"
+#include <assert.h>
+#include <errno.h>
+#include <string.h>
+
+error_t *const err_encoder_invalid_register =
+    &(error_t){.message = "Invalid register"};
+error_t *const err_encoder_number_overflow =
+    &(error_t){.message = "Number overflows the storage"};
+error_t *const err_encoder_invalid_number_format =
+    &(error_t){.message = "Invalid number format"};
+error_t *const err_encoder_invalid_size_suffix =
+    &(error_t){.message = "Invalid number size suffix"};
+error_t *const err_encoder_unknown_symbol_reference =
+    &(error_t){.message = "Referenced an unknown symbol"};
+
+error_t *encoder_alloc(encoder_t **output) {
+    *output = nullptr;
+    encoder_t *encoder = calloc(1, sizeof(encoder_t));
+
+    if (encoder == nullptr)
+        return err_allocation_failed;
+
+    error_t *err = symbol_table_alloc(&encoder->symbols);
+    if (err) {
+        free(encoder);
+        return err;
+    }
+
+    *output = encoder;
+    return nullptr;
+}
+
+void encoder_free(encoder_t *encoder) {
+    if (encoder == nullptr)
+        return;
+    symbol_table_free(encoder->symbols);
+    free(encoder);
+}
+
+bool encoder_is_symbols_node(ast_node_t *node) {
+    switch (node->id) {
+    case NODE_LABEL:
+    case NODE_LABEL_REFERENCE:
+    case NODE_EXPORT_DIRECTIVE:
+    case NODE_IMPORT_DIRECTIVE:
+        return true;
+    default:
+        return false;
+    }
+}
+
+int encoder_get_number_base(ast_node_t *number) {
+    switch (number->children[0]->id) {
+    case NODE_BINARY:
+        return 2;
+    case NODE_OCTAL:
+        return 8;
+    case NODE_DECIMAL:
+        return 10;
+    case NODE_HEXADECIMAL:
+        return 16;
+    default:
+        assert(false);
+    }
+    __builtin_unreachable();
+}
+
+bool is_valid_size_suffix(int bits) {
+    switch (bits) {
+    case 0:
+    case 8:
+    case 16:
+    case 32:
+    case 64:
+        return true;
+    default:
+        return false;
+    }
+}
+
+bool is_overflow(uint64_t value, int bits) {
+    if (bits == 0 || bits >= 64)
+        return false;
+
+    uint64_t max_value = (1ULL << bits) - 1;
+    return value > max_value;
+}
+
+operand_size_t encoder_get_size_mask(uint64_t value, int bits) {
+    if (bits != 0)
+        return bits_to_operand_size(bits);
+
+    operand_size_t mask = OPERAND_SIZE_64;
+    if (value < (1ULL << 8))
+        mask |= OPERAND_SIZE_8;
+    if (value < (1ULL << 16))
+        mask |= OPERAND_SIZE_16;
+    if (value < (1ULL << 32))
+        mask |= OPERAND_SIZE_32;
+    return mask;
+}
+
+error_t *encoder_set_number_value(ast_node_t *node) {
+    assert(node->id == NODE_NUMBER);
+    assert(node->children[0]);
+    const char *number = node->children[0]->token_entry->token.value;
+    int base = encoder_get_number_base(node);
+
+    if (base != 10)
+        number += 2; // all except base 10 use a 0x, 0o or 0b prefix
+
+    char *endptr;
+    errno = 0;
+    uint64_t value = strtoull(number, &endptr, base);
+
+    if (errno == ERANGE)
+        return err_encoder_number_overflow;
+
+    if (endptr == number)
+        return err_encoder_invalid_number_format;
+
+    int bits = 0;
+    if (*endptr == ':') {
+        const char *suffix = endptr + 1;
+
+        bits = strtol(suffix, &endptr, 10);
+
+        if (endptr == suffix)
+            return err_encoder_invalid_number_format;
+    }
+
+    if (*endptr != '\0')
+        return err_encoder_invalid_number_format;
+
+    if (!is_valid_size_suffix(bits))
+        return err_encoder_invalid_size_suffix;
+
+    if (is_overflow(value, bits))
+        return err_encoder_number_overflow;
+
+    node->value.number.value = value;
+    node->value.number.size = encoder_get_size_mask(value, bits);
+
+    return nullptr;
+}
+
+error_t *encoder_set_register_value(ast_node_t *node) {
+    assert(node->id == NODE_REGISTER);
+
+    const char *value = node->token_entry->token.value;
+
+    for (size_t i = 0; registers[i] != nullptr; ++i) {
+        if (strcmp(value, registers[i]->name) == 0) {
+            node->value.reg.id = registers[i]->id;
+            node->value.reg.size = registers[i]->size;
+        }
+    }
+}
+
+/**
+ * Perform the initial pass over the AST. Records all symbols and sets the
+ * values of registers and numbers.
+ */
+error_t *encoder_first_pass(encoder_t *encoder, ast_node_t *node) {
+    error_t *err = nullptr;
+
+    if (encoder_is_symbols_node(node))
+        err = symbol_table_update(encoder->symbols, node);
+    else if (node->id == NODE_NUMBER)
+        err = encoder_set_number_value(node);
+    else if (node->id == NODE_REGISTER)
+        err = encoder_set_register_value(node);
+    if (err)
+        return err;
+
+    for (size_t i = 0; i < node->len; ++i) {
+        error_t *err = encoder_first_pass(encoder, node->children[i]);
+        if (err)
+            return err;
+    }
+
+    return nullptr;
+}
+
+opcode_data_t *encoder_find_opcode(ast_node_t *instruction) {
+    for (size_t i = 0; opcodes[i] != nullptr; ++i) {
+    }
+    return nullptr;
+}
+
+error_t *encoder_check_symbols(encoder_t *encoder) {
+    for (size_t i = 0; i < encoder->symbols->len; ++i)
+        if (encoder->symbols->symbols[i].kind == SYMBOL_REFERENCE)
+            return err_encoder_unknown_symbol_reference;
+    return nullptr;
+}
+
+error_t *encoder_encode(encoder_t *encoder, ast_node_t *ast) {
+    error_t *err = encoder_first_pass(encoder, ast);
+    if (err)
+        return err;
+    err = encoder_check_symbols(encoder);
+    if (err)
+        return err;
+    return nullptr;
+}

src/encoder/encoder.h

@@ -0,0 +1,20 @@
+#ifndef INCLUDE_ENCODER_ENCODER_H_
+#define INCLUDE_ENCODER_ENCODER_H_
+
+#include "symbols.h"
+
+typedef struct encoder {
+    symbol_table_t *symbols;
+} encoder_t;
+
+error_t *encoder_alloc(encoder_t **encoder);
+error_t *encoder_encode(encoder_t *encoder, ast_node_t *ast);
+void encoder_free(encoder_t *encoder);
+
+extern error_t *const err_encoder_invalid_register;
+extern error_t *const err_encoder_number_overflow;
+extern error_t *const err_encoder_invalid_number_format;
+extern error_t *const err_encoder_invalid_size_suffix;
+extern error_t *const err_encoder_unknown_symbol_reference;
+
+#endif // INCLUDE_ENCODER_ENCODER_H_