From 10bb8a05088f1d3bb24f7167f609b5f6fb0ba026 Mon Sep 17 00:00:00 2001
From: Johnny Richard <johnny@johnnyrichard.com>
Date: Wed, 30 Oct 2024 22:58:03 +0100
Subject: bootstrap project

Signed-off-by: Johnny Richard <johnny@johnnyrichard.com>
---
 src/arena.c          | 121 ++++++++++++++++++++++++++++
 src/array.c          |  67 +++++++++++++++
 src/ir.c             |  42 ++++++++++
 src/lexer.c          | 222 ++++++++++++++++++++++++++++++++++++++++++++++++++
 src/obe.c            | 142 ++++++++++++++++++++++++++++++++
 src/parser.c         | 224 +++++++++++++++++++++++++++++++++++++++++++++++++++
 src/string.c         |  34 ++++++++
 src/utils.c          |  74 +++++++++++++++++
 src/x86_64/codegen.c | 152 ++++++++++++++++++++++++++++++++++
 9 files changed, 1078 insertions(+)
 create mode 100644 src/arena.c
 create mode 100644 src/array.c
 create mode 100644 src/ir.c
 create mode 100644 src/lexer.c
 create mode 100644 src/obe.c
 create mode 100644 src/parser.c
 create mode 100644 src/string.c
 create mode 100644 src/utils.c
 create mode 100644 src/x86_64/codegen.c

(limited to 'src')

diff --git a/src/arena.c b/src/arena.c
new file mode 100644
index 0000000..8822fdd
--- /dev/null
+++ b/src/arena.c
@@ -0,0 +1,121 @@
+/*
+ * Copyright (C) 2025 Johnny Richard <johnny@johnnyrichard.com>
+ *
+ * SPDX-License-Identifier: LGPL-3.0-or-later
+ *
+ * This file is part of obe.
+ *
+ * obe is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ *
+ * obe is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with obe. If not, see <https://www.gnu.org/licenses/>.
+ */
+#include <assert.h>
+#include <obe/arena.h>
+#include <stdlib.h>
+#include <string.h>
+
+void*
+obe_arena_alloc(obe_arena_t* arena, size_t size)
+{
+    if (arena->end == NULL) {
+        assert(arena->begin == NULL);
+        size_t capacity = OBE_ARENA_REGION_DEFAULT_CAPACITY;
+        if (capacity < OBE_ARENA_PADDING(size))
+            capacity = size + OBE_ARENA_PADDING(size);
+        arena->end = obe_arena_region_new(capacity);
+        arena->begin = arena->end;
+    }
+
+    while (arena->end->offset + size > arena->end->capacity &&
+           arena->end->next != NULL) {
+        arena->end = arena->end->next;
+    }
+
+    if (arena->end->offset + size > arena->end->capacity) {
+        assert(arena->end->next == NULL);
+        size_t capacity = OBE_ARENA_REGION_DEFAULT_CAPACITY;
+        if (capacity < size)
+            capacity = size + OBE_ARENA_PADDING(size);
+        arena->end->next = obe_arena_region_new(capacity);
+        arena->end = arena->end->next;
+    }
+
+    void* ptr = arena->end->data + arena->end->offset;
+    arena->end->offset += size + OBE_ARENA_PADDING(size);
+    return ptr;
+}
+
+void*
+obe_arena_realloc(obe_arena_t* arena,
+                  void* old_ptr,
+                  size_t old_size,
+                  size_t new_size)
+{
+    if (new_size <= old_size)
+        return old_ptr;
+    void* new_ptr = obe_arena_alloc(arena, new_size);
+    return memcpy(new_ptr, old_ptr, old_size);
+}
+
+void
+obe_arena_release(obe_arena_t* arena)
+{
+    for (obe_arena_region_t* r = arena->begin; r != NULL; r = r->next) {
+        r->offset = 0;
+    }
+    arena->end = arena->begin;
+}
+
+void
+obe_arena_free(obe_arena_t* arena)
+{
+    obe_arena_region_t* r = arena->begin;
+    while (r) {
+        obe_arena_region_t* r_tmp = r;
+        r = r->next;
+        obe_arena_region_free(r_tmp);
+    }
+    arena->begin = NULL;
+    arena->end = NULL;
+}
+
+obe_arena_region_t*
+obe_arena_region_new(size_t capacity)
+{
+    size_t size = sizeof(obe_arena_region_t) + sizeof(uint8_t) * capacity;
+    obe_arena_region_t* r = (obe_arena_region_t*)malloc(size);
+    assert(r);
+    r->next = NULL;
+    r->offset = 0;
+    r->capacity = capacity;
+    r->data = (uint8_t*)(r + 1);
+    return r;
+}
+
+void
+obe_arena_region_free(obe_arena_region_t* r)
+{
+    free(r);
+}
+
+char*
+obe_arena_strdup(obe_arena_t* arena, char* s)
+{
+    size_t slen = strlen(s);
+    char* d = obe_arena_alloc(arena, sizeof(char) * (slen + 1));
+    assert(d);
+
+    for (size_t i = 0; i <= slen; ++i)
+        d[i] = s[i];
+
+    return d;
+}
diff --git a/src/array.c b/src/array.c
new file mode 100644
index 0000000..dde3eba
--- /dev/null
+++ b/src/array.c
@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2025  Johnny Richard <johnny@johnnyrichard.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+#include <assert.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#include <obe/arena.h>
+#include <obe/array.h>
+
+void*
+obe_array_new(obe_arena_t* arena, size_t item_size)
+{
+    obe_array_header_t* h = obe_arena_alloc(
+      arena,
+      (item_size * OBE_ARRAY_INITIAL_CAPACITY) + sizeof(obe_array_header_t));
+    if (h == NULL) {
+        return NULL;
+    }
+    h->arena = arena;
+    h->length = 0;
+    h->item_size = item_size;
+    h->capacity = OBE_ARRAY_INITIAL_CAPACITY;
+
+    return ((uint8_t *)h) + sizeof(obe_array_header_t);
+}
+
+obe_array_header_t*
+obe_array_get_header(void* arr)
+{
+    return (obe_array_header_t*)(((uint8_t *)arr) - sizeof(obe_array_header_t));
+}
+
+void*
+obe_array_grow(void* arr)
+{
+    obe_array_header_t* h = obe_array_get_header(arr);
+
+    size_t old_size = sizeof(obe_array_header_t) + (h->capacity * h->item_size);
+    h->capacity *= 2;
+    size_t new_size = sizeof(obe_array_header_t) + (h->capacity * h->item_size);
+
+    h = obe_arena_realloc(h->arena, h, old_size, new_size);
+
+    return ((uint8_t *)h) + sizeof(obe_array_header_t);
+}
+
+size_t
+obe_array_length(void* arr)
+{
+    assert(arr);
+    obe_array_header_t* header = obe_array_get_header(arr);
+    return header->length;
+}
diff --git a/src/ir.c b/src/ir.c
new file mode 100644
index 0000000..2c0b0c9
--- /dev/null
+++ b/src/ir.c
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2025 Johnny Richard <johnny@johnnyrichard.com>
+ *
+ * SPDX-License-Identifier: LGPL-3.0-or-later
+ *
+ * This file is part of obe.
+ *
+ * obe is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ *
+ * obe is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with obe. If not, see <https://www.gnu.org/licenses/>.
+ */
+#include <assert.h>
+#include <obe/arena.h>
+#include <obe/ir.h>
+#include <obe/array.h>
+
+obe_ir_translation_unit_t*
+obe_ir_translation_unit_new(obe_arena_t* arena)
+{
+    obe_ir_translation_unit_t* tu = obe_arena_alloc(arena, sizeof(obe_ir_translation_unit_t));
+    assert(tu);
+    tu->funcs = obe_array(arena, obe_ir_function_t);
+    return tu;
+}
+
+obe_ir_function_t*
+obe_ir_function_new(obe_arena_t* arena, obe_string_t name)
+{
+    obe_ir_function_t* func = obe_arena_alloc(arena, sizeof(obe_ir_function_t));
+    assert(func);
+    func->name = name;
+    return func;
+}
diff --git a/src/lexer.c b/src/lexer.c
new file mode 100644
index 0000000..3ad8751
--- /dev/null
+++ b/src/lexer.c
@@ -0,0 +1,222 @@
+/*
+ * Copyright (C) 2025 Johnny Richard <johnny@johnnyrichard.com>
+ *
+ * SPDX-License-Identifier: LGPL-3.0-or-later
+ *
+ * This file is part of obe.
+ *
+ * obe is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ *
+ * obe is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with obe. If not, see <https://www.gnu.org/licenses/>.
+ */
+#include <assert.h>
+#include <ctype.h>
+#include <obe/lexer.h>
+#include <obe/string.h>
+#include <obe/utils.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+void
+obe_lexer_init(obe_lexer_t* lexer, char* filename)
+{
+    assert(lexer);
+
+    char* program = read_file_contents(filename);
+    if (program == NULL) {
+        fprintf(stderr, "Unable to read file contents <%s>\n", filename);
+        exit(EXIT_FAILURE);
+    }
+
+    lexer->filename = filename;
+    lexer->loc = (obe_lexer_loc_t){ 0 };
+    lexer->source = obe_string_from_cstr(program);
+}
+
+bool
+obe_lexer_is_eof(obe_lexer_t* lexer)
+{
+    return !(lexer->loc.offset < lexer->source.length);
+}
+
+char
+obe_lexer_current_char(obe_lexer_t* lexer)
+{
+    return lexer->source.chars[lexer->loc.offset];
+}
+
+char
+obe_lexer_next_char(obe_lexer_t* lexer)
+{
+    assert(lexer->loc.offset < lexer->source.length);
+
+    char previous_char = obe_lexer_current_char(lexer);
+    if (previous_char == '\n') {
+        lexer->loc.lineno++;
+        lexer->loc.lineoffset = ++lexer->loc.offset;
+    } else {
+        lexer->loc.offset++;
+    }
+    return obe_lexer_current_char(lexer);
+}
+
+void
+obe_lexer_next_token(obe_lexer_t* lexer, obe_token_t* token)
+{
+    if (obe_lexer_is_eof(lexer)) {
+        *token = (obe_token_t){ .kind = TOKEN_EOF };
+        return;
+    }
+
+    char c = obe_lexer_current_char(lexer);
+    if (isspace(c) && !obe_lexer_is_eof(lexer)) {
+        while (isspace(c) && !obe_lexer_is_eof(lexer)) {
+            c = obe_lexer_next_char(lexer);
+        }
+    }
+
+    if (obe_lexer_is_eof(lexer)) {
+        *token = (obe_token_t){ .kind = TOKEN_EOF };
+        return;
+    }
+
+    if (isalpha(c) || c == '_') {
+        obe_lexer_loc_t start_loc = lexer->loc;
+        while ((isalnum(c) || c == '_') && !obe_lexer_is_eof(lexer)) {
+            c = obe_lexer_next_char(lexer);
+        }
+        obe_string_t token_value = {
+            .chars = lexer->source.chars + start_loc.offset,
+            .length = lexer->loc.offset - start_loc.offset
+        };
+        token->value = token_value;
+        token->loc = start_loc;
+        if (obe_string_eq(token_value, obe_string_from_cstr("fn"))) {
+            token->kind = TOKEN_KW_FN;
+            return;
+        }
+        if (obe_string_eq(token_value, obe_string_from_cstr("br"))) {
+            token->kind = TOKEN_KW_BR;
+            return;
+        }
+        if (obe_string_eq(token_value,
+                               obe_string_from_cstr("return"))) {
+            token->kind = TOKEN_KW_RETURN;
+            return;
+        }
+        if (obe_string_eq(token_value, obe_string_from_cstr("int"))) {
+            token->kind = TOKEN_INT;
+            return;
+        }
+        token->kind = TOKEN_IDENT;
+        return;
+    }
+
+    if (c == '.') {
+        obe_lexer_loc_t start_loc = lexer->loc;
+        do {
+            c = obe_lexer_next_char(lexer);
+        } while ((isalnum(c) || c == '_') && !obe_lexer_is_eof(lexer));
+
+        obe_string_t token_value = {
+            .chars = lexer->source.chars + start_loc.offset,
+            .length = lexer->loc.offset - start_loc.offset
+        };
+
+        token->value = token_value;
+        token->loc = start_loc;
+        token->kind = TOKEN_LABEL;
+        return;
+    }
+
+    if (isdigit(c)) {
+        obe_lexer_loc_t start_loc = lexer->loc;
+        while (isdigit(c) && !obe_lexer_is_eof(lexer)) {
+            c = obe_lexer_next_char(lexer);
+        }
+        obe_string_t token_value = {
+            .chars = lexer->source.chars + start_loc.offset,
+            .length = lexer->loc.offset - start_loc.offset
+        };
+        token->kind = TOKEN_NUMBER;
+        token->value = token_value;
+        token->loc = start_loc;
+        return;
+    }
+
+    if (c == ';') {
+        token->kind = TOKEN_SEMICOLON;
+        token->loc = lexer->loc;
+        token->value = (obe_string_t){ .chars = lexer->source.chars + lexer->loc.offset, .length = 1 };
+        obe_lexer_next_char(lexer);
+        return;
+    }
+
+    if (c == ':') {
+        token->kind = TOKEN_COLON;
+        token->value = (obe_string_t){ .chars = lexer->source.chars + lexer->loc.offset , .length = 1} ;
+        token->loc = lexer->loc;
+        obe_lexer_next_char(lexer);
+        return;
+    }
+
+    if (c == '=') {
+        token->kind = TOKEN_EQ;
+        token->value = (obe_string_t){ .chars = lexer->source.chars + lexer->loc.offset, .length = 1 };
+        token->loc = lexer->loc;
+        obe_lexer_next_char(lexer);
+        return;
+    }
+
+    if (c == '{') {
+        token->kind = TOKEN_LBRACE;
+        token->value = (obe_string_t){ .chars = lexer->source.chars + lexer->loc.offset, .length = 1 };
+        token->loc = lexer->loc;
+        obe_lexer_next_char(lexer);
+        return;
+    }
+
+    if (c == '}') {
+        token->kind = TOKEN_RBRACE;
+        token->value = (obe_string_t){ .chars = lexer->source.chars + lexer->loc.offset, .length = 1 };
+        token->loc = lexer->loc;
+        obe_lexer_next_char(lexer);
+        return;
+    }
+
+    token->kind = TOKEN_UNKOWN;
+    token->value = (obe_string_t){ .chars = lexer->source.chars + lexer->loc.offset, .length = 1 };
+    token->loc = lexer->loc;
+    obe_lexer_next_char(lexer);
+    return;
+}
+
+static char* token_to_cstr_table[] = { [TOKEN_KW_RETURN] = "return",
+                                       [TOKEN_KW_FN] = "fn",
+                                       [TOKEN_KW_BR] = "br",
+                                       [TOKEN_IDENT] = "<ident>",
+                                       [TOKEN_LABEL] = "<label>",
+                                       [TOKEN_NUMBER] = "<number>",
+                                       [TOKEN_INT] = "int",
+                                       [TOKEN_EQ] = "=",
+                                       [TOKEN_COLON] = ":",
+                                       [TOKEN_SEMICOLON] = ";",
+                                       [TOKEN_LBRACE] = "{",
+                                       [TOKEN_RBRACE] = "}",
+                                       [TOKEN_EOF] = "<eof>",
+                                       [TOKEN_UNKOWN] = "<?unkown?>" };
+
+char*
+obe_token_to_cstr(obe_token_kind_t kind)
+{
+    return token_to_cstr_table[kind];
+}
diff --git a/src/obe.c b/src/obe.c
new file mode 100644
index 0000000..38af876
--- /dev/null
+++ b/src/obe.c
@@ -0,0 +1,142 @@
+/*
+ * Copyright (C) 2024 Johnny Richard <johnny@johnnyrichard.com>
+ *
+ * SPDX-License-Identifier: LGPL-3.0-or-later
+ *
+ * This file is part of obe.
+ *
+ * obe is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ *
+ * obe is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with obe. If not, see <https://www.gnu.org/licenses/>.
+ */
+#include <config.h>
+#include <obe/parser.h>
+#include <obe/x86_64/codegen.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+typedef struct obe_cli_args
+{
+    int argc;
+    char** argv;
+} obe_cli_args_t;
+
+typedef struct obe_cli_opts
+{
+    uint32_t options;
+    char* ir_file;
+    char* program_path;
+} obe_cli_opts_t;
+
+typedef enum
+{
+    OBE_CLI_OPT_HELP = 1,
+    OBE_CLI_OPT_VERSION = 1 << 1,
+    OBE_CLI_OPT_OUTPUT = 1 << 2,
+} cli_opt_t;
+
+obe_cli_opts_t
+obe_cli_parse_args(int argc, char** argv);
+
+static char*
+obe_cli_args_shift(obe_cli_args_t* args)
+{
+    if (args->argc == 0)
+        return NULL;
+    --(args->argc);
+    return *(args->argv)++;
+}
+
+void
+obe_cli_print_usage(FILE* stream)
+{
+    fprintf(stream,
+            "Usage: " PACKAGE_NAME " [OPTIONS] file...\n"
+            "\n"
+            "Options:\n"
+            "  -h, --help    display the help and exit\n"
+            "  -v, --version output version information and exit\n"
+            "  -o, --output  output gas assembly\n"
+            "\n"
+            "Report bugs to " PACKAGE_BUGREPORT "\n");
+}
+
+void
+obe_cli_print_version(void)
+{
+    printf(PACKAGE_STRING
+           "\n"
+           "\n"
+           "Copyright (C) 2025 Olang project.\n"
+           "This is free software; see the source for copying conditions.  "
+           "There is NO\n"
+           "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR "
+           "PURPOSE.\n"
+           "\n"
+           "Written by Johnny Richard <johnny@johnnyrichard.com>\n");
+}
+
+int
+main(int argc, char** argv)
+{
+    obe_cli_opts_t opts = { 0 };
+    obe_cli_args_t args = { .argc = argc, .argv = argv };
+
+    opts.program_path = obe_cli_args_shift(&args);
+
+    char* arg = obe_cli_args_shift(&args);
+    while (arg != NULL) {
+        if (strcmp(arg, "-h") == 0 || strcmp(arg, "--help") == 0) {
+            opts.options |= OBE_CLI_OPT_HELP;
+        } else if (strcmp(arg, "-v") == 0 || strcmp(arg, "--version") == 0) {
+            opts.options |= OBE_CLI_OPT_VERSION;
+        } else if (strcmp(arg, "-o") == 0 || strcmp(arg, "--output") == 0) {
+            opts.options |= OBE_CLI_OPT_OUTPUT;
+        } else {
+            opts.ir_file = arg;
+        }
+        arg = obe_cli_args_shift(&args);
+    }
+
+    if (opts.ir_file != NULL) {
+        obe_arena_t arena = { 0 };
+
+        obe_lexer_t lexer = { 0 };
+        obe_lexer_init(&lexer, opts.ir_file);
+
+        obe_parser_t parser = { 0 };
+        obe_parser_init(&parser, &lexer, &arena);
+        obe_ir_translation_unit_t* tu = obe_parser_parse(&parser);
+
+        obe_x86_64_codegen_emit(tu, stdout);
+        return EXIT_SUCCESS;
+    }
+
+    if (opts.options & OBE_CLI_OPT_HELP) {
+        obe_cli_print_usage(stdout);
+        return EXIT_SUCCESS;
+    }
+
+    if (opts.options & OBE_CLI_OPT_VERSION) {
+        obe_cli_print_version();
+        return EXIT_SUCCESS;
+    }
+
+    if (opts.options & OBE_CLI_OPT_OUTPUT) {
+        return EXIT_SUCCESS;
+    }
+
+    obe_cli_print_usage(stderr);
+    return EXIT_FAILURE;
+}
diff --git a/src/parser.c b/src/parser.c
new file mode 100644
index 0000000..d95e6f9
--- /dev/null
+++ b/src/parser.c
@@ -0,0 +1,224 @@
+/*
+ * Copyright (C) 2025 Johnny Richard <johnny@johnnyrichard.com>
+ *
+ * SPDX-License-Identifier: LGPL-3.0-or-later
+ *
+ * This file is part of obe.
+ *
+ * obe is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ *
+ * obe is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with obe. If not, see <https://www.gnu.org/licenses/>.
+ */
+#include <assert.h>
+#include <obe/array.h>
+#include <obe/lexer.h>
+#include <obe/parser.h>
+#include <stdbool.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+static obe_ir_function_t obe_parser_parse_function(obe_parser_t* parser);
+
+inline static bool expected_next_token(obe_lexer_t *lexer, obe_token_t *token,
+        obe_token_kind_t expected_kind);
+
+static bool expected_token(obe_lexer_t *lexer, obe_token_t *token,
+        obe_token_kind_t expected_kind);
+
+void
+obe_parser_init(obe_parser_t* parser, obe_lexer_t* lexer, obe_arena_t* arena)
+{
+    assert(parser && lexer && arena);
+    parser->lexer = lexer;
+    parser->arena = arena;
+}
+
+void
+obe_parser_next_expected_token(obe_parser_t* parser,
+                               obe_token_t* token,
+                               obe_token_kind_t kind)
+{
+    obe_lexer_next_token(parser->lexer, token);
+    if (token->kind != kind) {
+        fprintf(stderr,
+                "%s:%zu:%zu: syntax error: expected token <%s> but got <%s>.\n",
+                parser->lexer->filename,
+                token->loc.lineno + 1,
+                token->loc.offset - token->loc.lineoffset + 1,
+                obe_token_to_cstr(kind),
+                obe_token_to_cstr(token->kind));
+        exit(EXIT_FAILURE);
+    }
+}
+
+obe_ir_translation_unit_t*
+obe_parser_parse(obe_parser_t* parser)
+{
+    obe_ir_translation_unit_t* tu = obe_ir_translation_unit_new(parser->arena);
+
+    // FIXME: Add support to parse multiple functions
+    obe_array_append(tu->funcs, obe_parser_parse_function(parser));
+
+    return tu;
+}
+
+static obe_ir_function_t
+obe_parser_parse_function(obe_parser_t* parser)
+{
+    obe_token_t token;
+
+    expected_next_token(parser->lexer, &token, TOKEN_KW_FN);
+    expected_next_token(parser->lexer, &token, TOKEN_IDENT);
+
+    obe_ir_function_t func = { .name = token.value, .instrs = obe_array(parser->arena, obe_ir_inst_t) };
+
+    expected_next_token(parser->lexer, &token, TOKEN_LBRACE);
+
+    obe_lexer_next_token(parser->lexer, &token);
+    while (token.kind != TOKEN_EOF && token.kind != TOKEN_RBRACE) {
+        switch (token.kind) {
+            case TOKEN_KW_RETURN:
+                {
+                    expected_next_token(parser->lexer, &token, TOKEN_IDENT);
+                    
+                    char value[token.value.length + 1];
+                    memcpy(value, token.value.chars, token.value.length);
+                    value[token.value.length] = 0;
+
+                    obe_ir_inst_t inst = {
+                        .kind = OBE_IR_INST_RETURN,
+                        .operand1 = (obe_ir_operand_t) {
+                            .kind = OBE_IR_OPERAND_IDENT,
+                            .value = obe_arena_strdup(parser->arena, value)
+                        }
+                    };
+
+                    obe_array_append(func.instrs, inst);
+
+                    expected_next_token(parser->lexer, &token, TOKEN_SEMICOLON);
+                } break;
+            case TOKEN_KW_BR:
+                {
+                    expected_next_token(parser->lexer, &token, TOKEN_IDENT);
+                    
+                    char op1[token.value.length + 1];
+                    memcpy(op1, token.value.chars, token.value.length);
+                    op1[token.value.length] = 0;
+
+                    expected_next_token(parser->lexer, &token, TOKEN_LABEL);
+
+                    char dest[token.value.length + 1];
+                    memcpy(dest, token.value.chars, token.value.length);
+                    dest[token.value.length] = 0;
+
+                    expected_next_token(parser->lexer, &token, TOKEN_SEMICOLON);
+
+                    obe_ir_inst_t inst = {
+                        .kind = OBE_IR_INST_BR,
+                        .dest = obe_arena_strdup(parser->arena, dest),
+                        .operand1 = (obe_ir_operand_t) {
+                            .kind = OBE_IR_OPERAND_IDENT,
+                            .value = obe_arena_strdup(parser->arena, op1)
+                        }
+                    };
+
+                    obe_array_append(func.instrs, inst);
+                } break;
+            case TOKEN_LABEL:
+                {
+                    char label[token.value.length + 1];
+                    memcpy(label, token.value.chars, token.value.length);
+                    label[token.value.length] = 0;
+
+                    expected_next_token(parser->lexer, &token, TOKEN_COLON);
+
+                    obe_ir_inst_t inst = {
+                        .kind = OBE_IR_INST_LABEL,
+                        .dest = obe_arena_strdup(parser->arena, label)
+                    };
+
+                    obe_array_append(func.instrs, inst);
+                } break;
+            case TOKEN_IDENT:
+                {
+                    obe_string_t val = token.value;
+
+                    char dest[token.value.length + 1];
+                    memcpy(dest, token.value.chars, token.value.length);
+                    dest[token.value.length] = 0;
+
+                    expected_next_token(parser->lexer, &token, TOKEN_COLON);
+                    expected_next_token(parser->lexer, &token, TOKEN_INT);
+                    expected_next_token(parser->lexer, &token, TOKEN_EQ);
+                    expected_next_token(parser->lexer, &token, TOKEN_NUMBER);
+
+
+                    char number[token.value.length + 1];
+                    memcpy(number, token.value.chars, token.value.length);
+                    number[token.value.length] = 0;
+
+                    obe_ir_inst_t inst = {
+                        .kind = OBE_IR_INST_CONST,
+                        .type = OBE_IR_TYPE_INT,
+                        .dest = obe_arena_strdup(parser->arena, dest),
+                        .operand1 = (obe_ir_operand_t) {
+                            .kind = OBE_IR_OPERAND_LITERAL,
+                            .value = obe_arena_strdup(parser->arena, number)
+                        }
+                    };
+
+                    obe_array_append(func.instrs, inst);
+
+                    expected_next_token(parser->lexer, &token, TOKEN_SEMICOLON);
+                } break;
+            default:
+                {
+                    printf("%s:%ld:%ld: token <" PRIs ">\n",
+                           parser->lexer->filename,
+                           token.loc.lineno + 1,
+                           token.loc.offset - token.loc.lineoffset + 1,
+                           PRIsARG(token.value));
+                }
+        }
+        obe_lexer_next_token(parser->lexer, &token);
+    }
+
+    expected_token(parser->lexer, &token, TOKEN_RBRACE);
+
+    return func;
+}
+
+static bool
+expected_token(obe_lexer_t *lexer, obe_token_t *token, obe_token_kind_t expected_kind)
+{
+    if (token->kind != expected_kind) {
+        fprintf(stderr,
+                "%s:%lu:%lu: syntax error: got '" PRIs "' token but expect '%s'\n",
+                lexer->filename,
+                token->loc.lineno + 1,
+                token->loc.offset - lexer->loc.lineoffset + 1,
+                PRIsARG(token->value),
+                obe_token_to_cstr(expected_kind));
+        exit(EXIT_FAILURE);
+    }
+    return true;
+}
+
+inline static bool
+expected_next_token(obe_lexer_t *lexer,
+                    obe_token_t *token,
+                    obe_token_kind_t expected_kind)
+{
+    obe_lexer_next_token(lexer, token);
+    return expected_token(lexer, token, expected_kind);
+}
diff --git a/src/string.c b/src/string.c
new file mode 100644
index 0000000..b6638bd
--- /dev/null
+++ b/src/string.c
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2025 Johnny Richard <johnny@johnnyrichard.com>
+ *
+ * SPDX-License-Identifier: LGPL-3.0-or-later
+ *
+ * This file is part of obe.
+ *
+ * obe is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ *
+ * obe is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with obe. If not, see <https://www.gnu.org/licenses/>.
+ */
+#include <obe/string.h>
+#include <string.h>
+
+obe_string_t
+obe_string_from_cstr(char* cstr)
+{
+    return (obe_string_t){ .chars = cstr, .length = strlen(cstr) };
+}
+
+bool
+obe_string_eq(obe_string_t s1, obe_string_t s2)
+{
+    return s1.length == s2.length && memcmp(s1.chars, s2.chars, s1.length) == 0;
+}
diff --git a/src/utils.c b/src/utils.c
new file mode 100644
index 0000000..345d5a4
--- /dev/null
+++ b/src/utils.c
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2025 Johnny Richard <johnny@johnnyrichard.com>
+ *
+ * SPDX-License-Identifier: LGPL-3.0-or-later
+ *
+ * This file is part of obe.
+ *
+ * obe is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ *
+ * obe is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with obe. If not, see <https://www.gnu.org/licenses/>.
+ */
+#include <obe/utils.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+char*
+read_file_contents(char* file_path)
+{
+    FILE* file;
+    int file_size;
+
+    file = fopen(file_path, "r");
+
+    if (file == NULL) {
+        perror("fopen");
+        return NULL;
+    }
+
+    if (fseek(file, 0, SEEK_END) == -1) {
+        perror("fseek SEEK_END");
+        fclose(file);
+        return NULL;
+    }
+
+    if ((file_size = ftell(file)) == -1) {
+        perror("ftell");
+        fclose(file);
+        return NULL;
+    }
+
+    if (fseek(file, 0, SEEK_SET) == -1) {
+        perror("fseek 0 SEEK_SET");
+        fclose(file);
+        return NULL;
+    }
+
+    char* file_content = (char*)calloc(file_size + 1, sizeof(char));
+    if (file_content == NULL) {
+        fprintf(stderr, "Could not allocate mem for file_content\n");
+        fclose(file);
+        return NULL;
+    }
+
+    size_t ret = fread(file_content, sizeof(char), file_size, file);
+    if (ret == 0 && ferror(file) != 0) {
+        perror("fread");
+        free(file_content);
+        fclose(file);
+        return NULL;
+    }
+
+    fclose(file);
+
+    return file_content;
+}
diff --git a/src/x86_64/codegen.c b/src/x86_64/codegen.c
new file mode 100644
index 0000000..6cafda0
--- /dev/null
+++ b/src/x86_64/codegen.c
@@ -0,0 +1,152 @@
+/*
+ * Copyright (C) 2025 Johnny Richard <johnny@johnnyrichard.com>
+ *
+ * SPDX-License-Identifier: LGPL-3.0-or-later
+ *
+ * This file is part of obe.
+ *
+ * obe is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ *
+ * obe is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with obe. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <obe/arena.h>
+#include <obe/array.h>
+#include <obe/ir.h>
+#include <obe/x86_64/codegen.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+static void
+obe_x86_64_codegen_emit_function(obe_ir_function_t *fn, FILE *out)
+{
+    fprintf(out, PRIs ":\n", PRIsARG(fn->name));
+    fprintf(out, "\tpush %%rbp\n");
+    fprintf(out, "\tmov %%rsp, %%rbp\n");
+
+    size_t insts_length = obe_array_length(fn->instrs);
+    for (size_t i = 0; i < insts_length; ++i) {
+        obe_ir_inst_t inst = fn->instrs[i];
+        switch (inst.kind) {
+            case OBE_IR_INST_RETURN:
+                {
+                    if (inst.operand1.kind == OBE_IR_OPERAND_LITERAL) {
+                        fprintf(out, "\tmov $%s, %%rax\n", inst.operand1.value);
+                    } else {
+                        fprintf(stderr, "Operation kind not supported\n");
+                        exit(EXIT_FAILURE);
+                    }
+                } break;
+            default:
+                {
+                    fprintf(stderr, "Instruction not supported\n");
+                    exit(EXIT_FAILURE);
+                }
+        }
+    }
+
+    fprintf(out, "\tleave\n");
+    fprintf(out, "\tret\n");
+}
+
+void
+_obe_x86_64_codegen_emit(obe_ir_translation_unit_t* tu, FILE *out)
+{
+    // FIXME: Add syntax to configure globl
+    fprintf(out, ".globl main\n");
+
+    fprintf(out, ".text\n");
+    size_t funcs_length = obe_array_length(tu->funcs);
+    for (size_t i = 0; i < funcs_length; ++i) {
+        obe_ir_function_t fn = tu->funcs[i];
+        obe_x86_64_codegen_emit_function(&fn, out);
+    }
+}
+
+typedef struct obe_basic_block obe_basic_block_t;
+typedef struct obe_cfg obe_cfg_t;
+typedef struct obe_int_graph obe_int_graph_t;
+
+struct obe_basic_block {
+    obe_string_t id;
+    obe_ir_inst_t *instrs;
+    struct obe_basic_block *pred;
+    struct obe_basic_block *succ;
+};
+
+struct obe_cfg {
+    obe_basic_block_t *init_block;
+    obe_basic_block_t *curr_block;
+};
+
+
+typedef struct obe_int_edge {
+    size_t v1;
+    size_t v2;
+} obe_int_edge_t;
+
+struct obe_int_graph {
+    obe_int_edge_t *edges;
+};
+
+obe_int_graph_t
+create_interference_graph(obe_cfg_t *cfg, obe_arena_t *arena)
+{
+    obe_int_graph_t graph = {0};
+    graph.edges = obe_array(arena, obe_int_edge_t);
+
+    return graph;
+}
+
+void
+obe_x86_64_codegen_emit(obe_ir_translation_unit_t* tu, FILE *out)
+{
+    // FIXME: Create a valid CFG
+    obe_arena_t arena = {0};
+    obe_cfg_t cfg = {0};
+if (cfg.init_block == NULL) {
+        cfg.init_block = obe_arena_alloc(&arena, sizeof(obe_basic_block_t));
+        cfg.curr_block = cfg.init_block;
+        cfg.curr_block->instrs = obe_array(&arena, obe_ir_inst_t);
+    }
+
+    size_t funcs_length = obe_array_length(tu->funcs);
+    for (size_t i = 0; i < funcs_length; ++i) {
+        obe_ir_function_t fn = tu->funcs[i];
+
+        size_t instrs_length = obe_array_length(fn.instrs);
+        for (size_t j = 0; j < instrs_length; ++j) {
+            obe_ir_inst_t inst = fn.instrs[j];
+            switch (inst.kind) {
+                default:
+                    {
+                        obe_array_append(cfg.curr_block->instrs, inst);
+                    }
+            }
+        }
+    }
+
+    // TODO: Register Allocation
+    // liveness analysis (create interference graph)
+    size_t instrs_length = obe_array_length(cfg.init_block->instrs);
+    for (size_t i = 0; i < instrs_length; ++i) {
+        obe_ir_inst_t inst = cfg.init_block->instrs[i];
+        // asm("int3");
+        printf("inst = %d\n", inst.kind);
+    }
+    // TODO: create_interference_graph(&cfg, &arena);
+
+
+    // TODO: Emit assembly code
+    
+    obe_arena_free(&arena);
+}
-- 
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