vm.h

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/*
 * This file is part of the Fun programming language.
 * https://fun-lang.xyz/
 *
 * Copyright 2025 Johannes Findeisen <you@hanez.org>
 * Licensed under the terms of the Apache-2.0 license.
 * https://opensource.org/license/apache-2-0
 */

#ifndef FUN_VM_H
#define FUN_VM_H

#include "bytecode.h"
#include <stddef.h>

#ifndef MAX_FRAMES
#define MAX_FRAMES 128
#endif

#ifndef MAX_FRAME_LOCALS
#define MAX_FRAME_LOCALS 64
#endif

#ifndef MAX_GLOBALS
#define MAX_GLOBALS 128
#endif

#ifndef OUTPUT_SIZE
#define OUTPUT_SIZE 1024
#endif

#ifndef STACK_SIZE
#define STACK_SIZE 1024
#endif

static const char *opcode_names[] = {
 "NOP", "LOAD_CONST", "LOAD_LOCAL", "STORE_LOCAL",
 "LOAD_GLOBAL", "STORE_GLOBAL", "ADD", "SUB", "MUL", "DIV",
 "LT", "LTE", "GT", "GTE", "EQ", "NEQ", "POP", "JUMP",
 "JUMP_IF_FALSE", "CALL", "RETURN", "PRINT", "ECHO", "HALT",
 "LINE",
 "MOD", "AND", "OR", "NOT", "DUP", "SWAP",
 "MAKE_ARRAY", "INDEX_GET", "INDEX_SET",
 "LEN", "PUSH", "APOP", "SET", "INSERT", "REMOVE", "SLICE",
 "TO_NUMBER", "TO_STRING", "CAST", "TYPEOF",
 "SPLIT", "JOIN", "SUBSTR", "FIND",
 "REGEX_MATCH", "REGEX_SEARCH", "REGEX_REPLACE",
 "CONTAINS", "INDEX_OF", "CLEAR",
 "ENUMERATE", "ZIP",
 "MIN", "MAX", "CLAMP", "ABS", "POW", "RANDOM_SEED", "RANDOM_INT",
 "MAKE_MAP", "KEYS", "VALUES", "HAS_KEY",
 "READ_FILE", "WRITE_FILE", "ENV", "INPUT_LINE", "PROC_RUN", "PROC_SYSTEM",
 "TIME_NOW_MS", "CLOCK_MONO_MS", "DATE_FORMAT",
 "THREAD_SPAWN", "THREAD_JOIN", "SLEEP_MS",
 "RANDOM_NUMBER",
 "BAND", "BOR", "BXOR", "BNOT", "SHL", "SHR", "ROTL", "ROTR",
 "JSON_PARSE", "JSON_STRINGIFY", "JSON_FROM_FILE", "JSON_TO_FILE",
 "CURL_GET", "CURL_POST", "CURL_DOWNLOAD",
 "SQLITE_OPEN", "SQLITE_CLOSE", "SQLITE_EXEC", "SQLITE_QUERY",
 "LIBSQL_OPEN", "LIBSQL_CLOSE", "LIBSQL_EXEC", "LIBSQL_QUERY",
 "PCSC_ESTABLISH", "PCSC_RELEASE", "PCSC_LIST_READERS", "PCSC_CONNECT", "PCSC_DISCONNECT", "PCSC_TRANSMIT",
 "PCRE2_TEST", "PCRE2_MATCH", "PCRE2_FINDALL",
 "INI_LOAD", "INI_FREE", "INI_GET_STRING", "INI_GET_INT", "INI_GET_DOUBLE", "INI_GET_BOOL", "INI_SET", "INI_UNSET", "INI_SAVE",
 "XML_PARSE", "XML_ROOT", "XML_NAME", "XML_TEXT",
 "SOCK_TCP_LISTEN", "SOCK_TCP_ACCEPT", "SOCK_TCP_CONNECT", "SOCK_SEND", "SOCK_RECV", "SOCK_CLOSE", "SOCK_UNIX_LISTEN", "SOCK_UNIX_CONNECT",
 "FD_SET_NONBLOCK", "FD_POLL_READ", "FD_POLL_WRITE",
 "EXIT",
 "OS_LIST_DIR",
 "SERIAL_OPEN", "SERIAL_CONFIG", "SERIAL_SEND", "SERIAL_RECV", "SERIAL_CLOSE",
 "TRY_PUSH", "TRY_POP", "THROW",
 "FMIN", "FMAX",
 /* Rust FFI demo */
 "RUST_HELLO", "RUST_HELLO_ARGS", "RUST_HELLO_ARGS_RETURN", "RUST_GET_SP", "RUST_SET_EXIT",
 /* C++ demo */
 "CPP_ADD"};

typedef struct {
 Bytecode *fn;
 int ip;
 Value locals[MAX_FRAME_LOCALS];
 /* exception handling (per-frame) */
 int try_stack[16];
 int try_sp; /* -1 when empty */
} Frame;

struct VM {
 Value stack[STACK_SIZE];
 int sp;

 Frame frames[MAX_FRAMES];
 int fp; // frame pointer, -1 when no frame

 Value globals[MAX_GLOBALS];

 Value output[OUTPUT_SIZE]; // store printed values
 int output_count;
 int output_is_partial[OUTPUT_SIZE]; // 1 when the corresponding output entry should not end with newline (echo)

 long long instr_count; // executed instructions in the last vm_run

 int current_line; // last executed source line (debug)

 int exit_code; // process exit code set by OP_EXIT

 int trace_enabled; // when non-zero, print executed ops and stack
 int repl_on_error; // when non-zero, enter REPL on runtime error (preserve stack)
 int (*on_error_repl)(struct VM *vm); // optional hook to run REPL on error

 /* --- Debugger state --- */
 int debug_step_mode; // 0 none, 1 step, 2 next, 3 finish
 int debug_step_target_fp; // target frame pointer for next/finish
 long long debug_step_start_ic; // instruction count snapshot when step/next requested
 int debug_stop_requested; // force a pause at loop top

 struct {
 char *file; // strdup'ed file path
 int line; // 1-based line
 int active; // 1 if active
 } breakpoints[64];
 int break_count; // number of active breakpoints
};

typedef struct VM VM;

void vm_init(VM *vm);

void vm_clear_output(VM *vm);
void vm_print_output(VM *vm);
void vm_free(VM *vm);

void vm_reset(VM *vm);

void vm_dump_globals(VM *vm);
void vm_run(VM *vm, Bytecode *entry);

void vm_raise_error(VM *vm, const char *msg);

/* --- Debugger API --- */
void vm_debug_reset(VM *vm);
int vm_debug_add_breakpoint(VM *vm, const char *file, int line);
int vm_debug_delete_breakpoint(VM *vm, int id);
void vm_debug_clear_breakpoints(VM *vm);
void vm_debug_list_breakpoints(VM *vm);
void vm_debug_request_step(VM *vm);
void vm_debug_request_next(VM *vm);
void vm_debug_request_finish(VM *vm);
void vm_debug_request_continue(VM *vm);

static inline int opcode_is_valid(int op) {
 return op >= OP_NOP && op <= OP_CPP_ADD; // all current opcodes
}

/* --- Minimal C ABI helpers for FFI (Rust opcode experiments) --- */
int64_t vm_pop_i64(VM *vm);
void vm_push_i64(VM *vm, int64_t v);

int fun_op_radd(VM *vm);

const char *fun_rust_get_string(void);
int fun_rust_print_string(const char *msg);
char *fun_rust_echo_string(const char *input);
void fun_rust_string_free(char *ptr);

int fun_op_cpp_add(struct VM *vm);

/* --- Extended C ABI for Rust to access VM internals (unsafe) --- */
size_t vm_sizeof(void);
size_t vm_value_sizeof(void);

void *vm_as_mut_ptr(VM *vm);

size_t vm_offset_of_exit_code(void);
size_t vm_offset_of_sp(void);
size_t vm_offset_of_stack(void);
size_t vm_offset_of_globals(void);

/* Demo Rust ops using the extended ABI */
int fun_op_rget_sp(VM *vm);
int fun_op_rset_exit(VM *vm);

#endif