commit 25e35083bda3ccebcf97f98019432bd88410c3ff
Author: SimonFJ20 <simonfromjakobsen@gmail.com>
Date:   Tue Aug 29 21:02:20 2023 +0200

    init

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..4a60d05
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+
+program
+
diff --git a/build.sh b/build.sh
new file mode 100644
index 0000000..82751fd
--- /dev/null
+++ b/build.sh
@@ -0,0 +1,4 @@
+#!/bin/bash
+
+gcc -o program main.c -std=c17 -Wall -Wextra -Wpedantic -O3
+
diff --git a/compile_flags.txt b/compile_flags.txt
new file mode 100644
index 0000000..42511b4
--- /dev/null
+++ b/compile_flags.txt
@@ -0,0 +1,7 @@
+-xc
+-std=c17
+-Wall
+-Wextra
+-Wpedantic
+-O3
+
diff --git a/debug.sh b/debug.sh
new file mode 100644
index 0000000..7550f41
--- /dev/null
+++ b/debug.sh
@@ -0,0 +1,8 @@
+#!/bin/bash
+
+set -xe
+
+gcc -o program main.c -std=c17 -Wall -Wextra -Wpedantic -O3 -g -fsanitize=address,undefined
+
+./program
+
diff --git a/main.c b/main.c
new file mode 100644
index 0000000..51eb875
--- /dev/null
+++ b/main.c
@@ -0,0 +1,896 @@
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+
+typedef enum {
+    Token_Eof,
+    Token_Plus,
+    Token_Minus,
+    Token_LT,
+    Token_GT,
+    Token_Dot,
+    Token_Comma,
+    Token_LBracket,
+    Token_RBracket
+} Token;
+
+typedef struct {
+    const char* text;
+    size_t index;
+    size_t length;
+} Lexer;
+
+Lexer lexer_create(const char* text, size_t length)
+{
+    return (Lexer) { .text = text, .index = 0, .length = length };
+}
+
+void lexer_step(Lexer* lexer) { lexer->index += 1; }
+
+Token lexer_next(Lexer* lexer)
+{
+    if (lexer->index >= lexer->length) {
+        return Token_Eof;
+    }
+    switch (lexer->text[lexer->index]) {
+        case '+':
+            return (lexer_step(lexer), Token_Plus);
+        case '-':
+            return (lexer_step(lexer), Token_Minus);
+        case '<':
+            return (lexer_step(lexer), Token_LT);
+        case '>':
+            return (lexer_step(lexer), Token_GT);
+        case '.':
+            return (lexer_step(lexer), Token_Dot);
+        case ',':
+            return (lexer_step(lexer), Token_Comma);
+        case '[':
+            return (lexer_step(lexer), Token_LBracket);
+        case ']':
+            return (lexer_step(lexer), Token_RBracket);
+        default:
+            return (lexer_step(lexer), lexer_next(lexer));
+    }
+}
+
+typedef enum {
+    ExprType_Error,
+    ExprType_Incr,
+    ExprType_Decr,
+    ExprType_Left,
+    ExprType_Right,
+    ExprType_Output,
+    ExprType_Input,
+    ExprType_Loop,
+    ExprType_Zero,
+} ExprType;
+
+typedef struct Expr Expr;
+
+typedef struct ExprVec {
+    Expr* data;
+    size_t capacity;
+    size_t length;
+} ExprVec;
+
+struct Expr {
+    ExprType type;
+    union {
+        int value;
+        ExprVec exprs;
+    };
+};
+
+void expr_vec_construct(ExprVec* vec)
+{
+    *vec = (ExprVec) {
+        .data = malloc(sizeof(Expr) * 8),
+        .capacity = 8,
+        .length = 0,
+    };
+}
+void expr_vec_destroy(ExprVec* vec) { free(vec->data); }
+
+void expr_free(Expr* expr);
+void expr_vec_free(ExprVec* vec)
+{
+    for (size_t i = 0; i < vec->length; ++i) {
+        expr_free(&vec->data[i]);
+    }
+    expr_vec_destroy(vec);
+}
+
+void expr_vec_push(ExprVec* vec, Expr expr)
+{
+    if (vec->length + 1 > vec->capacity) {
+        vec->capacity *= 2;
+        vec->data = realloc(vec->data, sizeof(Expr) * vec->capacity);
+    }
+    vec->data[vec->length] = expr;
+    vec->length += 1;
+}
+Expr expr_vec_pop(ExprVec* vec)
+{
+    vec->length -= 1;
+    return vec->data[vec->length];
+}
+
+void expr_free(Expr* expr)
+{
+    switch (expr->type) {
+        case ExprType_Loop:
+            expr_vec_free(&expr->exprs);
+            break;
+        default:
+            break;
+    }
+}
+
+const char* color_reset = "\x1b[0m";
+const char* color_bold = "\x1b[1m";
+
+const char* color_black = "\x1b[30m";
+const char* color_red = "\x1b[31m";
+const char* color_green = "\x1b[32m";
+const char* color_yellow = "\x1b[33m";
+const char* color_blue = "\x1b[34m";
+const char* color_magenta = "\x1b[35m";
+const char* color_cyan = "\x1b[36m";
+const char* color_bright_gray = "\x1b[37m";
+
+const char* color_gray = "\x1b[90m";
+const char* color_bright_red = "\x1b[91m";
+const char* color_bright_green = "\x1b[92m";
+const char* color_bright_yellow = "\x1b[93m";
+const char* color_bright_blue = "\x1b[94m";
+const char* color_bright_magenta = "\x1b[95m";
+const char* color_bright_cyan = "\x1b[96m";
+const char* color_white = "\x1b[97m";
+
+const char* expr_bracket_color(int depth)
+{
+    switch (depth % 3) {
+        case 0:
+            return color_bright_yellow;
+        case 1:
+            return color_magenta;
+        case 2:
+            return color_cyan;
+    }
+    return NULL;
+}
+
+void expr_stringify_concat_value(Expr* expr, char* acc, int depth)
+{
+    strcat(acc, color_bold);
+    strcat(acc, expr_bracket_color(depth));
+    strcat(acc, "(");
+    strcat(acc, color_reset);
+    char value[16] = { 0 };
+    snprintf(value, 16, "%d", expr->value);
+    strcat(acc, value);
+    strcat(acc, color_bold);
+    strcat(acc, expr_bracket_color(depth));
+    strcat(acc, ")");
+    strcat(acc, color_reset);
+}
+
+void expr_stringify(Expr* expr, char* acc, int depth);
+
+void expr_vec_stringify(ExprVec* vec, char* acc, int depth)
+{
+    strcat(acc, color_bold);
+    strcat(acc, expr_bracket_color(depth));
+    strcat(acc, "[");
+    strcat(acc, color_reset);
+    for (size_t i = 0; i < vec->length; ++i) {
+        if (i != 0) {
+            strcat(acc, " ");
+        }
+        expr_stringify(&vec->data[i], acc, depth + 1);
+    }
+    strcat(acc, color_bold);
+    strcat(acc, expr_bracket_color(depth));
+    strcat(acc, "]");
+    strcat(acc, color_reset);
+}
+
+void expr_stringify(Expr* expr, char* acc, int depth)
+{
+    switch (expr->type) {
+        case ExprType_Error:
+            strcat(acc, color_bright_red);
+            strcat(acc, "Error");
+            strcat(acc, color_reset);
+            break;
+        case ExprType_Incr:
+            strcat(acc, color_yellow);
+            strcat(acc, "Incr");
+            strcat(acc, color_reset);
+            expr_stringify_concat_value(expr, acc, depth);
+            break;
+        case ExprType_Decr:
+            strcat(acc, color_yellow);
+            strcat(acc, "Decr");
+            strcat(acc, color_reset);
+            expr_stringify_concat_value(expr, acc, depth);
+            break;
+        case ExprType_Left:
+            strcat(acc, color_green);
+            strcat(acc, "Left");
+            strcat(acc, color_reset);
+            expr_stringify_concat_value(expr, acc, depth);
+            break;
+        case ExprType_Right:
+            strcat(acc, color_green);
+            strcat(acc, "Right");
+            strcat(acc, color_reset);
+            expr_stringify_concat_value(expr, acc, depth);
+            break;
+        case ExprType_Output:
+            strcat(acc, color_bright_gray);
+            strcat(acc, "Output");
+            strcat(acc, color_reset);
+            break;
+        case ExprType_Input:
+            strcat(acc, color_bright_gray);
+            strcat(acc, "Input");
+            strcat(acc, color_reset);
+            break;
+        case ExprType_Loop:
+            strcat(acc, color_bright_red);
+            strcat(acc, "Loop");
+            expr_vec_stringify(&expr->exprs, acc, depth);
+            strcat(acc, color_reset);
+            break;
+        case ExprType_Zero:
+            strcat(acc, color_yellow);
+            strcat(acc, "Zero");
+            strcat(acc, color_reset);
+            break;
+    }
+}
+
+bool expr_equal(const Expr* self, const Expr* other);
+
+bool expr_vec_equal(const ExprVec* self, const ExprVec* other)
+{
+    if (self->length != other->length) {
+        return false;
+    }
+    for (size_t i = 0; i < self->length; ++i) {
+        if (!expr_equal(&self->data[i], &other->data[i])) {
+            return false;
+        }
+    }
+    return true;
+}
+
+bool expr_equal(const Expr* self, const Expr* other)
+{
+    if (self->type != other->type) {
+        return false;
+    }
+    switch (self->type) {
+        case ExprType_Incr:
+        case ExprType_Decr:
+        case ExprType_Left:
+        case ExprType_Right:
+            if (self->value != other->value) {
+                return false;
+            }
+            break;
+        case ExprType_Loop:
+            if (!expr_vec_equal(&self->exprs, &other->exprs)) {
+                return false;
+            }
+            break;
+        default:
+            break;
+    }
+    return true;
+}
+
+typedef struct {
+    Lexer lexer;
+    Token current;
+} Parser;
+
+Parser parser_create(const char* text, size_t length)
+{
+    Lexer lexer = lexer_create(text, length);
+    return (Parser) {
+        .lexer = lexer,
+        .current = lexer_next(&lexer),
+    };
+}
+
+void parser_step(Parser* parser)
+{
+    parser->current = lexer_next(&parser->lexer);
+}
+
+Expr parser_parse_expr(Parser* parser);
+
+Expr parser_parse_loop(Parser* parser)
+{
+    parser_step(parser);
+    ExprVec exprs;
+    expr_vec_construct(&exprs);
+    while (parser->current != Token_Eof && parser->current != Token_RBracket) {
+        expr_vec_push(&exprs, parser_parse_expr(parser));
+    }
+    if (parser->current != Token_RBracket) {
+        return (Expr) { .type = ExprType_Error };
+    }
+    parser_step(parser);
+    return (Expr) { .type = ExprType_Loop, .exprs = exprs };
+}
+
+Expr parser_parse_expr(Parser* parser)
+{
+    switch (parser->current) {
+        case Token_Plus:
+            return (
+                parser_step(parser),
+                (Expr) { .type = ExprType_Incr, .value = 1 }
+            );
+        case Token_Minus:
+            return (
+                parser_step(parser),
+                (Expr) { .type = ExprType_Decr, .value = 1 }
+            );
+        case Token_LT:
+            return (
+                parser_step(parser),
+                (Expr) { .type = ExprType_Left, .value = 1 }
+            );
+        case Token_GT:
+            return (
+                parser_step(parser),
+                (Expr) { .type = ExprType_Right, .value = 1 }
+            );
+        case Token_Dot:
+            return (parser_step(parser), (Expr) { .type = ExprType_Output });
+        case Token_Comma:
+            return (parser_step(parser), (Expr) { .type = ExprType_Input });
+        case Token_LBracket:
+            return parser_parse_loop(parser);
+        default:
+            return (parser_step(parser), (Expr) { .type = ExprType_Error });
+    }
+}
+
+ExprVec parser_parse(Parser* parser)
+{
+    ExprVec exprs;
+    expr_vec_construct(&exprs);
+    while (parser->current != Token_Eof) {
+        expr_vec_push(&exprs, parser_parse_expr(parser));
+    }
+    return exprs;
+}
+
+Expr expr_optimize_fold_adjecent(const Expr* expr);
+ExprVec expr_vec_optimize_fold_adjecent(const ExprVec* vec)
+{
+    ExprVec exprs;
+    expr_vec_construct(&exprs);
+    if (vec->length == 0) {
+        return exprs;
+    }
+    Expr a = expr_optimize_fold_adjecent(&vec->data[0]);
+    for (size_t i = 1; i < vec->length; ++i) {
+        Expr b = expr_optimize_fold_adjecent(&vec->data[i]);
+        switch (a.type) {
+            case ExprType_Incr:
+            case ExprType_Decr:
+            case ExprType_Left:
+            case ExprType_Right:
+                if (a.type != b.type) {
+                    expr_vec_push(&exprs, a);
+                    a = b;
+                } else {
+                    a.value += b.value;
+                }
+                break;
+            default:
+                expr_vec_push(&exprs, a);
+                a = b;
+        }
+    }
+    expr_vec_push(&exprs, a);
+    return exprs;
+}
+Expr expr_optimize_fold_adjecent(const Expr* expr)
+{
+    if (expr->type == ExprType_Loop) {
+        return (Expr) {
+            .type = ExprType_Loop,
+            .exprs = expr_vec_optimize_fold_adjecent(&expr->exprs),
+        };
+    } else {
+        return *expr;
+    }
+}
+
+Expr expr_optimize_eliminate_negation(const Expr* expr);
+ExprVec expr_vec_optimize_eliminate_negation(const ExprVec* vec)
+{
+    ExprVec exprs;
+    expr_vec_construct(&exprs);
+    if (vec->length == 0) {
+        return exprs;
+    }
+    expr_vec_push(&exprs, expr_optimize_eliminate_negation(&vec->data[0]));
+    for (size_t i = 1; i < vec->length; ++i) {
+        expr_vec_push(&exprs, expr_optimize_eliminate_negation(&vec->data[i]));
+        Expr* a = &exprs.data[i - 1];
+        Expr* b = &exprs.data[i];
+        if (a->type == ExprType_Incr && b->type == ExprType_Decr) {
+            if (a->value > b->value) {
+                a->value -= b->value;
+                expr_vec_pop(&exprs);
+            } else if (a->value < b->value) {
+                *a = (Expr) { .type = ExprType_Decr,
+                              .value = b->value - a->value };
+                expr_vec_pop(&exprs);
+            } else {
+                expr_vec_pop(&exprs);
+                expr_vec_pop(&exprs);
+            }
+        } else if (a->type == ExprType_Decr && b->type == ExprType_Incr) {
+            if (a->value > b->value) {
+                a->value -= b->value;
+                expr_vec_pop(&exprs);
+            } else if (a->value < b->value) {
+                *a = (Expr) { .type = ExprType_Incr,
+                              .value = b->value - a->value };
+                expr_vec_pop(&exprs);
+            } else {
+                expr_vec_pop(&exprs);
+                expr_vec_pop(&exprs);
+            }
+        }
+        if (a->type == ExprType_Left && b->type == ExprType_Right) {
+            if (a->value > b->value) {
+                a->value -= b->value;
+                expr_vec_pop(&exprs);
+            } else if (a->value < b->value) {
+                *a = (Expr) { .type = ExprType_Right,
+                              .value = b->value - a->value };
+                expr_vec_pop(&exprs);
+            } else {
+                expr_vec_pop(&exprs);
+                expr_vec_pop(&exprs);
+            }
+        } else if (a->type == ExprType_Right && b->type == ExprType_Left) {
+            if (a->value > b->value) {
+                a->value -= b->value;
+                expr_vec_pop(&exprs);
+            } else if (a->value < b->value) {
+                *a = (Expr) { .type = ExprType_Left,
+                              .value = b->value - a->value };
+                expr_vec_pop(&exprs);
+            } else {
+                expr_vec_pop(&exprs);
+                expr_vec_pop(&exprs);
+            }
+        }
+    }
+    return exprs;
+}
+Expr expr_optimize_eliminate_negation(const Expr* expr)
+{
+    if (expr->type == ExprType_Loop) {
+        return (Expr) {
+            .type = ExprType_Loop,
+            .exprs = expr_vec_optimize_eliminate_negation(&expr->exprs),
+        };
+    } else {
+        return *expr;
+    }
+}
+
+Expr expr_optimize_eliminate_overflow(const Expr* expr);
+ExprVec expr_vec_optimize_eliminate_overflow(const ExprVec* vec)
+{
+    ExprVec exprs;
+    expr_vec_construct(&exprs);
+    for (size_t i = 0; i < vec->length; ++i) {
+        expr_vec_push(&exprs, expr_optimize_eliminate_overflow(&vec->data[i]));
+    }
+    return exprs;
+}
+Expr expr_optimize_eliminate_overflow(const Expr* expr)
+{
+    if (expr->type == ExprType_Loop) {
+        return (Expr) {
+            .type = ExprType_Loop,
+            .exprs = expr_vec_optimize_eliminate_overflow(&expr->exprs),
+        };
+    } else if (expr->value > 255) {
+        return (Expr) { .type = expr->type, .value = expr->value % 256 };
+    } else {
+        return *expr;
+    }
+}
+
+Expr expr_optimize_replace_zeroing_loops(const Expr* expr);
+ExprVec expr_vec_optimize_replace_zeroing_loops(const ExprVec* vec)
+{
+    ExprVec exprs;
+    expr_vec_construct(&exprs);
+    for (size_t i = 0; i < vec->length; ++i) {
+        expr_vec_push(
+            &exprs, expr_optimize_replace_zeroing_loops(&vec->data[i])
+        );
+    }
+    return exprs;
+}
+Expr expr_optimize_replace_zeroing_loops(const Expr* expr)
+{
+    if (expr->type == ExprType_Loop) {
+        if (expr->exprs.length == 1
+            && (expr->exprs.data[0].type == ExprType_Incr
+                || expr->exprs.data[0].type == ExprType_Decr)
+            && expr->exprs.data[0].value % 2 != 0) {
+            return (Expr) { .type = ExprType_Zero };
+        } else {
+            return (Expr) {
+                .type = ExprType_Loop,
+                .exprs = expr_vec_optimize_replace_zeroing_loops(&expr->exprs),
+            };
+        }
+    } else {
+        return *expr;
+    }
+}
+
+typedef struct {
+    uint8_t* code;
+    size_t pos;
+    int loop_counter;
+    bool cmp_flags_set;
+} Emitter;
+
+Emitter emitter_create(uint8_t* code_address)
+{
+    return (Emitter) {
+        .code = code_address,
+        .pos = 0,
+        .loop_counter = 0,
+        .cmp_flags_set = false,
+    };
+}
+
+void emitter_push_u8(Emitter* emitter, uint8_t value)
+{
+    emitter->code[emitter->pos] = value;
+    emitter->pos += 1;
+}
+
+void emitter_push_u32(Emitter* emitter, uint32_t value)
+{
+    emitter->code[emitter->pos] = value & 0xFF;
+    emitter->pos += 1;
+    emitter->code[emitter->pos] = (value >> 8) & 0xFF;
+    emitter->pos += 1;
+    emitter->code[emitter->pos] = (value >> 16) & 0xFF;
+    emitter->pos += 1;
+    emitter->code[emitter->pos] = value >> 24;
+    emitter->pos += 1;
+}
+
+void emitter_push_u64(Emitter* emitter, uint64_t value)
+{
+    emitter->code[emitter->pos] = value & 0xFF;
+    emitter->pos += 1;
+    emitter->code[emitter->pos] = (value >> 8) & 0xFF;
+    emitter->pos += 1;
+    emitter->code[emitter->pos] = (value >> 16) & 0xFF;
+    emitter->pos += 1;
+    emitter->code[emitter->pos] = (value >> 24) & 0xFF;
+    emitter->pos += 1;
+    emitter->code[emitter->pos] = (value >> 32) & 0xFF;
+    emitter->pos += 1;
+    emitter->code[emitter->pos] = (value >> 40) & 0xFF;
+    emitter->pos += 1;
+    emitter->code[emitter->pos] = (value >> 48) & 0xFF;
+    emitter->pos += 1;
+    emitter->code[emitter->pos] = (value >> 56) & 0xFF;
+    emitter->pos += 1;
+}
+
+uint8_t get_char(void) { return (uint8_t)fgetc(stdin); }
+void put_char(uint8_t v) { fputc(v, stdout); }
+
+void emitter_emit_expr(Emitter* emitter, Expr* expr)
+{
+    emitter->cmp_flags_set = false;
+    switch (expr->type) {
+        case ExprType_Error:
+            fprintf(stderr, "panic: emitter: program contained errors\n");
+            exit(1);
+            break;
+        case ExprType_Incr:
+            // add BYTE [rbx], 1
+            emitter_push_u8(emitter, 0x80);
+            emitter_push_u8(emitter, 0x03);
+            emitter_push_u8(emitter, expr->value);
+            emitter->cmp_flags_set = true;
+            break;
+        case ExprType_Decr:
+            // sub BYTE [rbx], 1
+            emitter_push_u8(emitter, 0x80);
+            emitter_push_u8(emitter, 0x2b);
+            emitter_push_u8(emitter, expr->value);
+            emitter->cmp_flags_set = true;
+            break;
+        case ExprType_Left:
+            // sub rbx, 1
+            emitter_push_u8(emitter, 0x48);
+            emitter_push_u8(emitter, 0x83);
+            emitter_push_u8(emitter, 0xeb);
+            emitter_push_u8(emitter, expr->value);
+            break;
+        case ExprType_Right:
+            // add rbx, 1
+            emitter_push_u8(emitter, 0x48);
+            emitter_push_u8(emitter, 0x83);
+            emitter_push_u8(emitter, 0xc3);
+            emitter_push_u8(emitter, expr->value);
+            break;
+        case ExprType_Output:
+            // movzx edi, BYTE [rbx]
+            emitter_push_u8(emitter, 0x0f);
+            emitter_push_u8(emitter, 0xb6);
+            emitter_push_u8(emitter, 0x3b);
+            // movabs rax, <put_char>
+            emitter_push_u8(emitter, 0x48);
+            emitter_push_u8(emitter, 0xb8);
+            emitter_push_u64(emitter, (uint64_t)put_char);
+            // call rax
+            emitter_push_u8(emitter, 0xff);
+            emitter_push_u8(emitter, 0xd0);
+            break;
+        case ExprType_Input:
+            // movabs rax, <put_char>
+            emitter_push_u8(emitter, 0x48);
+            emitter_push_u8(emitter, 0xb8);
+            emitter_push_u64(emitter, (uint64_t)get_char);
+            // call rax
+            emitter_push_u8(emitter, 0xff);
+            emitter_push_u8(emitter, 0xd0);
+            // mov BYTE [rbx], al
+            emitter_push_u8(emitter, 0x88);
+            emitter_push_u8(emitter, 0x03);
+            break;
+        case ExprType_Loop:
+            fprintf(stderr, "panic: emitter: unexpected loop\n");
+            exit(1);
+            break;
+        case ExprType_Zero:
+            // mov BYTE [rbx], 0
+            emitter_push_u8(emitter, 0xc6);
+            emitter_push_u8(emitter, 0x03);
+            emitter_push_u8(emitter, 0x00);
+            emitter->cmp_flags_set = true;
+            break;
+    }
+}
+
+void emitter_emit_expr_vec(Emitter* emitter, ExprVec* vec);
+
+void emitter_emit_loop(Emitter* emitter, Expr* expr)
+{
+    int64_t start_loc = (int64_t)&emitter->code[emitter->pos];
+    emitter_emit_expr_vec(emitter, &expr->exprs);
+    if (!emitter->cmp_flags_set) {
+        // cmp BYTE [rbx], 0
+        emitter_push_u8(emitter, 0x80);
+        emitter_push_u8(emitter, 0x3b);
+        emitter_push_u8(emitter, 0x00);
+    }
+
+    int64_t current_loc = (int64_t)&emitter->code[emitter->pos];
+    int32_t relative_address = -(int32_t)(current_loc - start_loc);
+    if (relative_address >= -127) {
+        // jne <current_loc: rel8>
+        emitter_push_u8(emitter, 0x75);
+        emitter_push_u8(emitter, (uint8_t)relative_address - 2);
+    } else {
+        // jne <current_loc: rel32>
+        emitter_push_u8(emitter, 0x0f);
+        emitter_push_u8(emitter, 0x85);
+        emitter_push_u32(emitter, (uint32_t)relative_address - 6);
+    }
+}
+
+void emitter_emit_expr_vec(Emitter* emitter, ExprVec* vec)
+{
+    for (size_t i = 0; i < vec->length; ++i) {
+        Expr* expr = &vec->data[i];
+        if (expr->type == ExprType_Loop) {
+            emitter_emit_loop(emitter, expr);
+        } else {
+            emitter_emit_expr(emitter, expr);
+        }
+    }
+}
+
+void emitter_emit_program(Emitter* emitter, ExprVec* program)
+{
+    // push rbp:
+    emitter_push_u8(emitter, 0x55);
+    // mov rbp, rsp
+    emitter_push_u8(emitter, 0x48);
+    emitter_push_u8(emitter, 0x89);
+    emitter_push_u8(emitter, 0xe5);
+    // push rbx:
+    emitter_push_u8(emitter, 0x53);
+    // mov rbx, rdi
+    emitter_push_u8(emitter, 0x48);
+    emitter_push_u8(emitter, 0x89);
+    emitter_push_u8(emitter, 0xfb);
+
+    emitter_emit_expr_vec(emitter, program);
+
+    // pop rbx
+    emitter_push_u8(emitter, 0x5b);
+    // pop rbx
+    emitter_push_u8(emitter, 0x5d);
+    // ret
+    emitter_push_u8(emitter, 0xc3);
+}
+
+int main(void)
+{
+    // const char* text
+    //     = "+++[>[-]++++++++++++++++++++++++++++++++++++++++++++++++++"
+    //       "++++++++++++++++++"
+    //       "++++.---.++++++++++++++++++++.[-]++++++++++.<-]";
+    const char* text = ">++[<+++++++++++++>-]<[[>+>+<<-]>[<+>-]++++++++"
+                       "[>++++++++<-]>.[-]<<>++++++++++[>++++++++++[>++"
+                       "++++++++[>++++++++++[>++++++++++[>++++++++++[>+"
+                       "+++++++++[-]<-]<-]<-]<-]<-]<-]<-]++++++++++.";
+
+    printf("\ntext:%s\n\"%s\"%s\n", color_bright_green, text, color_reset);
+
+    char* ast_string = malloc(sizeof(char) * 33768);
+    ast_string[0] = '\0';
+
+    Parser parser = parser_create(text, strlen(text));
+    ExprVec ast = parser_parse(&parser);
+    {
+        expr_vec_stringify(&ast, ast_string, 0);
+        printf("\nparsed:\n%s\n", ast_string);
+    }
+
+    ExprVec previous_ast;
+    bool first = true;
+    int pass_counter = 1;
+    while (first || !expr_vec_equal(&ast, &previous_ast)) {
+        printf(
+            "\n%soptimization pass %d:%s\n",
+            color_bold,
+            pass_counter,
+            color_reset
+        );
+        pass_counter += 1;
+
+        if (!first) {
+            expr_vec_free(&previous_ast);
+        }
+        previous_ast = ast;
+        ast = expr_vec_optimize_fold_adjecent(&ast);
+        printf("%sfold_adjecent:%s\n", color_bold, color_reset);
+        if (!expr_vec_equal(&ast, &previous_ast)) {
+            ast_string[0] = '\0';
+            expr_vec_stringify(&ast, ast_string, 0);
+            puts(ast_string);
+        }
+
+        expr_vec_free(&previous_ast);
+        previous_ast = ast;
+        ast = expr_vec_optimize_eliminate_negation(&ast);
+        printf("%seliminate_negation:%s\n", color_bold, color_reset);
+        if (!expr_vec_equal(&ast, &previous_ast)) {
+            ast_string[0] = '\0';
+            expr_vec_stringify(&ast, ast_string, 0);
+            puts(ast_string);
+        }
+
+        expr_vec_free(&previous_ast);
+        previous_ast = ast;
+        ast = expr_vec_optimize_eliminate_overflow(&ast);
+        printf("%seliminate_overflow:%s\n", color_bold, color_reset);
+        if (!expr_vec_equal(&ast, &previous_ast)) {
+            ast_string[0] = '\0';
+            expr_vec_stringify(&ast, ast_string, 0);
+            puts(ast_string);
+        }
+
+        expr_vec_free(&previous_ast);
+        previous_ast = ast;
+        ast = expr_vec_optimize_replace_zeroing_loops(&ast);
+        printf("%sreplace_zeroing_loops:%s\n", color_bold, color_reset);
+        if (!expr_vec_equal(&ast, &previous_ast)) {
+            ast_string[0] = '\0';
+            expr_vec_stringify(&ast, ast_string, 0);
+            puts(ast_string);
+        }
+
+        if (first) {
+            first = false;
+        }
+    }
+
+    ast_string[0] = '\0';
+    expr_vec_stringify(&ast, ast_string, 0);
+    printf("\n%sfinal:%s\n%s\n", color_bold, color_reset, ast_string);
+
+    size_t code_size = 33678;
+    uint8_t* code = mmap(
+        NULL,
+        code_size,
+        PROT_READ | PROT_WRITE | PROT_EXEC,
+        MAP_PRIVATE | MAP_ANONYMOUS,
+        -1,
+        0
+    );
+    if (code == NULL) {
+        fprintf(stderr, "panic: could not mmap\n");
+        exit(1);
+    }
+
+    Emitter emitter = emitter_create(code);
+    emitter_emit_program(&emitter, &ast);
+
+    uint8_t* memory = malloc(30000);
+    memset(memory, 0, 30000);
+
+    void (*runnable)(uint8_t* memory) = (void (*)(uint8_t* memory))(void*)code;
+
+    printf("\n%scode:%s\n", color_bold, color_reset);
+
+    for (size_t y = 0; y < 8; ++y) {
+        for (size_t x = 0; x < 8; ++x) {
+            uint8_t v = code[y * 8 + x];
+            if (v == 0) {
+                fputs(color_gray, stdout);
+            }
+            printf("%02x ", v);
+            fputs(color_reset, stdout);
+        }
+        printf("\n");
+    }
+
+    printf("\n%sresult:%s\n", color_bold, color_reset);
+
+    runnable(memory);
+
+    printf("\n%smemory:%s\n", color_bold, color_reset);
+
+    for (size_t y = 0; y < 8; ++y) {
+        for (size_t x = 0; x < 8; ++x) {
+            uint8_t v = memory[y * 8 + x];
+            if (v == 0) {
+                fputs(color_gray, stdout);
+            }
+            printf("%02x ", v);
+            fputs(color_reset, stdout);
+        }
+        printf("\n");
+    }
+
+    free(memory);
+    munmap(code, code_size);
+    expr_vec_free(&previous_ast);
+    expr_vec_free(&ast);
+    free(ast_string);
+}
diff --git a/tests/bench.bf b/tests/bench.bf
new file mode 100644
index 0000000..def9fbe
--- /dev/null
+++ b/tests/bench.bf
@@ -0,0 +1,5 @@
+>++[<+++++++++++++>-]<[[>+>+<<-]>[<+>-]++++++++
+[>++++++++<-]>.[-]<<>++++++++++[>++++++++++[>++
+++++++++[>++++++++++[>++++++++++[>++++++++++[>+
++++++++++[-]<-]<-]<-]<-]<-]<-]<-]++++++++++.
+
diff --git a/tests/hey_3x.bf b/tests/hey_3x.bf
new file mode 100644
index 0000000..3697c64
--- /dev/null
+++ b/tests/hey_3x.bf
@@ -0,0 +1,4 @@
++++[>[-]++++++++++++++++++++++++++++++++++++++++++++++++++
+++++++++++++++++++
+++++.---.++++++++++++++++++++.[-]++++++++++.<-]
+