Check crash arm runner.

macos actually works with 47-bit pointers.

.github/workflows/test.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ ubuntu-latest, macos-latest, macos-14, macos-15-intel ]
+        os: [ ubuntu-latest, ubuntu-24.04-arm, macos-latest, macos-14, macos-15-intel ]
     steps:
       - name: Checkout the repository
         uses: actions/checkout@master

meson.build

@@ -72,6 +72,9 @@ conf.set_quoted('JANET_VERSION', meson.project_version())
 # Use options
 conf.set_quoted('JANET_BUILD', get_option('git_hash'))
 conf.set('JANET_NO_NANBOX', not get_option('nanbox'))
+if get_option('nanbox_pointer_shift') != -1 # -1 is auto-detect
+  conf.set('JANET_NANBOX_64_POINTER_SHIFT', get_option('nanbox_pointer_shift'))
+endif
 conf.set('JANET_SINGLE_THREADED', get_option('single_threaded'))
 conf.set('JANET_NO_DYNAMIC_MODULES', not get_option('dynamic_modules'))
 conf.set('JANET_NO_DOCSTRINGS', not get_option('docstrings'))

meson_options.txt

@@ -2,6 +2,7 @@ option('git_hash', type : 'string', value : 'meson')
 
 option('single_threaded', type : 'boolean', value : false)
 option('nanbox', type : 'boolean', value : true)
+option('nanbox_pointer_shift', type : 'integer', min : -1, max : 4, value : -1)
 option('dynamic_modules', type : 'boolean', value : true)
 option('docstrings', type : 'boolean', value : true)
 option('sourcemaps', type : 'boolean', value : true)

src/conf/janetconf.h

@@ -16,6 +16,7 @@
 /* #define JANET_THREAD_LOCAL _Thread_local */
 /* #define JANET_NO_DYNAMIC_MODULES */
 /* #define JANET_NO_NANBOX */
+/* #define JANET_NANBOX_64_POINTER_SHIFT 0 */
 /* #define JANET_API __attribute__((visibility ("default"))) */
 
 /* These settings should be specified before amalgamation is

src/core/bytecode.c

@@ -29,7 +29,7 @@
 #endif
 
 /* Look up table for instructions */
-enum JanetInstructionType janet_instructions[JOP_INSTRUCTION_COUNT] = {
+const enum JanetInstructionType janet_instructions[JOP_INSTRUCTION_COUNT] = {
     JINT_0, /* JOP_NOOP, */
     JINT_S, /* JOP_ERROR, */
     JINT_ST, /* JOP_TYPECHECK, */

src/core/compile.c

@@ -94,11 +94,21 @@ void janetc_freeslot(JanetCompiler *c, JanetSlot s) {
 void janetc_nameslot(JanetCompiler *c, const uint8_t *sym, JanetSlot s, uint32_t flags) {
     if (!(flags & JANET_DEFFLAG_NO_SHADOWCHECK)) {
         if (sym[0] != '_') {
-            int check = janetc_shadowcheck(c, sym);
-            if (check == 2) {
-                janetc_lintf(c, JANET_C_LINT_NORMAL, "binding %q is shadowing a local binding", janet_wrap_symbol(sym));
-            } else if (check) {
-                janetc_lintf(c, JANET_C_LINT_NORMAL, "binding %q is shadowing a global binding", janet_wrap_symbol(sym));
+            switch (janetc_shadowcheck(c, sym)) {
+                default:
+                    break;
+                case JANETC_SHADOW_MACRO:
+                    janetc_lintf(c, JANET_C_LINT_NORMAL, "binding %q is shadowing a macro", janet_wrap_symbol(sym));
+                    break;
+                case JANETC_SHADOW_LOCAL_HIDES_LOCAL:
+                    janetc_lintf(c, JANET_C_LINT_STRICT, "binding %q is shadowing a binding", janet_wrap_symbol(sym));
+                    break;
+                case JANETC_SHADOW_LOCAL_HIDES_GLOBAL:
+                    janetc_lintf(c, JANET_C_LINT_STRICT, "binding %q is shadowing a top-level binding", janet_wrap_symbol(sym));
+                    break;
+                case JANETC_SHADOW_GLOBAL_HIDES_GLOBAL:
+                    janetc_lintf(c, JANET_C_LINT_STRICT, "top-level binding %q is shadowing another top-level binding", janet_wrap_symbol(sym));
+                    break;
             }
         }
     }
@@ -261,20 +271,34 @@ static int lookup_missing(
 
 /* Check if a binding is defined in an upper scope. This lets us check for
  * variable shadowing. */
-int janetc_shadowcheck(JanetCompiler *c, const uint8_t *sym) {
+Shadowing janetc_shadowcheck(JanetCompiler *c, const uint8_t *sym) {
     /* Check locals */
     JanetScope *scope = c->scope;
+    int is_global = (scope->flags & JANET_SCOPE_TOP);
     while (scope) {
         int32_t len = janet_v_count(scope->syms);
         for (int32_t i = len - 1; i >= 0; i--) {
             SymPair *pair = scope->syms + i;
-            if (pair->sym == sym) return 2;
+            if (pair->sym == sym) {
+                janet_assert(!is_global, "shadowing analysis is incorrect. compiler bug");
+                return JANETC_SHADOW_LOCAL_HIDES_LOCAL;
+            }
         }
         scope = scope->parent;
     }
     /* Check globals */
     JanetBinding binding = janet_resolve_ext(c->env, sym);
-    return binding.type != JANET_BINDING_NONE;
+    if (binding.type == JANET_BINDING_MACRO || binding.type == JANET_BINDING_DYNAMIC_MACRO) {
+        return JANETC_SHADOW_MACRO;
+    } else if (binding.type == JANET_BINDING_NONE) {
+        return JANETC_SHADOW_NONE;
+    } else {
+        if (is_global) {
+            return JANETC_SHADOW_GLOBAL_HIDES_GLOBAL;
+        } else {
+            return JANETC_SHADOW_LOCAL_HIDES_GLOBAL;
+        }
+    }
 }
 
 /* Allow searching for symbols. Return information about the symbol */

src/core/compile.h

@@ -36,6 +36,15 @@ typedef enum {
     JANET_C_LINT_STRICT
 } JanetCompileLintLevel;
 
+/* Kinds of variable shadowing for linting */
+typedef enum {
+    JANETC_SHADOW_NONE,
+    JANETC_SHADOW_MACRO,
+    JANETC_SHADOW_GLOBAL_HIDES_GLOBAL,
+    JANETC_SHADOW_LOCAL_HIDES_GLOBAL,
+    JANETC_SHADOW_LOCAL_HIDES_LOCAL
+} Shadowing;
+
 /* Tags for some functions for the prepared inliner */
 #define JANET_FUN_DEBUG 1
 #define JANET_FUN_ERROR 2
@@ -276,7 +285,7 @@ JanetSlot janetc_cslot(Janet x);
 JanetSlot janetc_resolve(JanetCompiler *c, const uint8_t *sym);
 
 /* Check if a symbol is already in scope for shadowing lints */
-int janetc_shadowcheck(JanetCompiler *c, const uint8_t *sym);
+Shadowing janetc_shadowcheck(JanetCompiler *c, const uint8_t *sym);
 
 /* Bytecode optimization */
 void janet_bytecode_movopt(JanetFuncDef *def);

src/core/corelib.c

@@ -70,7 +70,7 @@ JanetModule janet_native(const char *name, const uint8_t **error) {
             host.minor != modconf.minor ||
             host.bits != modconf.bits) {
         char errbuf[128];
-        snprintf(errbuf, sizeof(errbuf), "config mismatch - host %d.%.d.%d(%.4x) vs. module %d.%d.%d(%.4x)",
+        snprintf(errbuf, sizeof(errbuf), "config mismatch - host %d.%.d.%d(%.4x) vs. module %d.%d.%d(%.4x) - native needs to be recompiled!",
                  host.major,
                  host.minor,
                  host.patch,

src/core/inttypes.c

@@ -333,7 +333,7 @@ static int compare_uint64_double(uint64_t x, double y) {
     }
 }
 
-static Janet cfun_it_s64_compare(int32_t argc, Janet *argv) {
+static JANET_CFUNCTION_ALIGN Janet cfun_it_s64_compare(int32_t argc, Janet *argv) {
     janet_fixarity(argc, 2);
     if (janet_is_int(argv[0]) != JANET_INT_S64) {
         janet_panic("compare method requires int/s64 as first argument");
@@ -368,7 +368,7 @@ static Janet cfun_it_s64_compare(int32_t argc, Janet *argv) {
     return janet_wrap_nil();
 }
 
-static Janet cfun_it_u64_compare(int32_t argc, Janet *argv) {
+static JANET_CFUNCTION_ALIGN Janet cfun_it_u64_compare(int32_t argc, Janet *argv) {
     janet_fixarity(argc, 2);
     if (janet_is_int(argv[0]) != JANET_INT_U64) {
         janet_panic("compare method requires int/u64 as first argument");
@@ -416,7 +416,7 @@ static Janet cfun_it_u64_compare(int32_t argc, Janet *argv) {
  * This will not affect the end result (property of twos complement).
  */
 #define OPMETHOD(T, type, name, oper) \
-static Janet cfun_it_##type##_##name(int32_t argc, Janet *argv) { \
+static JANET_CFUNCTION_ALIGN Janet cfun_it_##type##_##name(int32_t argc, Janet *argv) { \
     janet_arity(argc, 2, -1); \
     T *box = janet_abstract(&janet_##type##_type, sizeof(T)); \
     *box = janet_unwrap_##type(argv[0]); \
@@ -427,7 +427,7 @@ static Janet cfun_it_##type##_##name(int32_t argc, Janet *argv) { \
 } \
 
 #define OPMETHODINVERT(T, type, name, oper) \
-static Janet cfun_it_##type##_##name##i(int32_t argc, Janet *argv) { \
+static JANET_CFUNCTION_ALIGN Janet cfun_it_##type##_##name##i(int32_t argc, Janet *argv) { \
     janet_fixarity(argc, 2); \
     T *box = janet_abstract(&janet_##type##_type, sizeof(T)); \
     *box = janet_unwrap_##type(argv[1]); \
@@ -437,7 +437,7 @@ static Janet cfun_it_##type##_##name##i(int32_t argc, Janet *argv) { \
 } \
 
 #define UNARYMETHOD(T, type, name, oper) \
-static Janet cfun_it_##type##_##name(int32_t argc, Janet *argv) { \
+static JANET_CFUNCTION_ALIGN Janet cfun_it_##type##_##name(int32_t argc, Janet *argv) { \
     janet_fixarity(argc, 1); \
     T *box = janet_abstract(&janet_##type##_type, sizeof(T)); \
     *box = oper(janet_unwrap_##type(argv[0])); \
@@ -450,7 +450,7 @@ static Janet cfun_it_##type##_##name(int32_t argc, Janet *argv) { \
 #define DIVZERO_mod return janet_wrap_abstract(box)
 
 #define DIVMETHOD(T, type, name, oper) \
-static Janet cfun_it_##type##_##name(int32_t argc, Janet *argv) { \
+static JANET_CFUNCTION_ALIGN Janet cfun_it_##type##_##name(int32_t argc, Janet *argv) { \
     janet_arity(argc, 2, -1);                       \
     T *box = janet_abstract(&janet_##type##_type, sizeof(T)); \
     *box = janet_unwrap_##type(argv[0]); \
@@ -463,7 +463,7 @@ static Janet cfun_it_##type##_##name(int32_t argc, Janet *argv) { \
 } \
 
 #define DIVMETHODINVERT(T, type, name, oper) \
-static Janet cfun_it_##type##_##name##i(int32_t argc, Janet *argv) { \
+static JANET_CFUNCTION_ALIGN Janet cfun_it_##type##_##name##i(int32_t argc, Janet *argv) { \
     janet_fixarity(argc, 2);                       \
     T *box = janet_abstract(&janet_##type##_type, sizeof(T)); \
     *box = janet_unwrap_##type(argv[1]); \
@@ -474,7 +474,7 @@ static Janet cfun_it_##type##_##name##i(int32_t argc, Janet *argv) { \
 } \
 
 #define DIVMETHOD_SIGNED(T, type, name, oper) \
-static Janet cfun_it_##type##_##name(int32_t argc, Janet *argv) { \
+static JANET_CFUNCTION_ALIGN Janet cfun_it_##type##_##name(int32_t argc, Janet *argv) { \
     janet_arity(argc, 2, -1);                       \
     T *box = janet_abstract(&janet_##type##_type, sizeof(T)); \
     *box = janet_unwrap_##type(argv[0]); \
@@ -488,7 +488,7 @@ static Janet cfun_it_##type##_##name(int32_t argc, Janet *argv) { \
 } \
 
 #define DIVMETHODINVERT_SIGNED(T, type, name, oper) \
-static Janet cfun_it_##type##_##name##i(int32_t argc, Janet *argv) { \
+static JANET_CFUNCTION_ALIGN Janet cfun_it_##type##_##name##i(int32_t argc, Janet *argv) { \
     janet_fixarity(argc, 2);                       \
     T *box = janet_abstract(&janet_##type##_type, sizeof(T)); \
     *box = janet_unwrap_##type(argv[1]); \
@@ -499,7 +499,7 @@ static Janet cfun_it_##type##_##name##i(int32_t argc, Janet *argv) { \
     return janet_wrap_abstract(box); \
 } \
 
-static Janet cfun_it_s64_divf(int32_t argc, Janet *argv) {
+static JANET_CFUNCTION_ALIGN Janet cfun_it_s64_divf(int32_t argc, Janet *argv) {
     janet_fixarity(argc, 2);
     int64_t *box = janet_abstract(&janet_s64_type, sizeof(int64_t));
     int64_t op1 = janet_unwrap_s64(argv[0]);
@@ -510,7 +510,7 @@ static Janet cfun_it_s64_divf(int32_t argc, Janet *argv) {
     return janet_wrap_abstract(box);
 }
 
-static Janet cfun_it_s64_divfi(int32_t argc, Janet *argv) {
+static JANET_CFUNCTION_ALIGN Janet cfun_it_s64_divfi(int32_t argc, Janet *argv) {
     janet_fixarity(argc, 2);
     int64_t *box = janet_abstract(&janet_s64_type, sizeof(int64_t));
     int64_t op2 = janet_unwrap_s64(argv[0]);
@@ -521,7 +521,7 @@ static Janet cfun_it_s64_divfi(int32_t argc, Janet *argv) {
     return janet_wrap_abstract(box);
 }
 
-static Janet cfun_it_s64_mod(int32_t argc, Janet *argv) {
+static JANET_CFUNCTION_ALIGN Janet cfun_it_s64_mod(int32_t argc, Janet *argv) {
     janet_fixarity(argc, 2);
     int64_t *box = janet_abstract(&janet_s64_type, sizeof(int64_t));
     int64_t op1 = janet_unwrap_s64(argv[0]);
@@ -535,7 +535,7 @@ static Janet cfun_it_s64_mod(int32_t argc, Janet *argv) {
     return janet_wrap_abstract(box);
 }
 
-static Janet cfun_it_s64_modi(int32_t argc, Janet *argv) {
+static JANET_CFUNCTION_ALIGN Janet cfun_it_s64_modi(int32_t argc, Janet *argv) {
     janet_fixarity(argc, 2);
     int64_t *box = janet_abstract(&janet_s64_type, sizeof(int64_t));
     int64_t op2 = janet_unwrap_s64(argv[0]);

src/core/strtod.c

@@ -49,6 +49,8 @@
 #include <math.h>
 #include <string.h>
 
+#define JANET_NUMBER_LENGTH_RIDICULOUS 0xFFFF
+
 /* Lookup table for getting values of characters when parsing numbers. Handles
  * digits 0-9 and a-z (and A-Z). A-Z have values of 10 to 35. */
 static uint8_t digit_lookup[128] = {
@@ -266,7 +268,7 @@ int janet_scan_number_base(
      * the decimal point, exponent could wrap around and become positive. It's
      * easier to reject ridiculously large inputs than to check for overflows.
      * */
-    if (len > INT32_MAX / 40) goto error;
+    if (len > JANET_NUMBER_LENGTH_RIDICULOUS) goto error;
 
     /* Get sign */
     if (str >= end) goto error;
@@ -410,10 +412,7 @@ static int scan_uint64(
     *neg = 0;
     *out = 0;
     uint64_t accum = 0;
-    /* len max is INT64_MAX in base 2 with _ between each bits */
-    /* '2r' + 64 bits + 63 _  + sign = 130 => 150 for some leading  */
-    /* zeros */
-    if (len > 150) return 0;
+    if (len > JANET_NUMBER_LENGTH_RIDICULOUS) return 0;
     /* Get sign */
     if (str >= end) return 0;
     if (*str == '-') {

src/core/util.c

@@ -573,8 +573,24 @@ static char *namebuf_name(NameBuf *namebuf, const char *suffix) {
     return (char *)(namebuf->buf);
 }
 
+/* Add a little bit of safety when using nanboxing on arm. Instead of inserting run-time checks everywhere, we are
+ * only doing it during registration which has much less cost (1 shift and mask). */
+static void janet_check_pointer_align(void *p) {
+    (void) p;
+#if defined(JANET_NANBOX_64) && JANET_NANBOX_64_POINTER_SHIFT != 0
+    union {
+        void *p;
+        uintptr_t u;
+    } un;
+    un.p = p;
+    janet_assert(!(un.u & (uintptr_t) ((1 << JANET_NANBOX_64_POINTER_SHIFT) - 1)),
+        "unaligned pointer wrap - cfunction pointers and abstract types must be aligned with this nanboxing configuration.");
+#endif
+}
+
 void janet_cfuns(JanetTable *env, const char *regprefix, const JanetReg *cfuns) {
     while (cfuns->name) {
+        janet_check_pointer_align(cfuns->cfun);
         Janet fun = janet_wrap_cfunction(cfuns->cfun);
         if (env) janet_def(env, cfuns->name, fun, cfuns->documentation);
         janet_registry_put(cfuns->cfun, cfuns->name, regprefix, NULL, 0);
@@ -584,6 +600,7 @@ void janet_cfuns(JanetTable *env, const char *regprefix, const JanetReg *cfuns)
 
 void janet_cfuns_ext(JanetTable *env, const char *regprefix, const JanetRegExt *cfuns) {
     while (cfuns->name) {
+        janet_check_pointer_align(cfuns->cfun);
         Janet fun = janet_wrap_cfunction(cfuns->cfun);
         if (env) janet_def_sm(env, cfuns->name, fun, cfuns->documentation, cfuns->source_file, cfuns->source_line);
         janet_registry_put(cfuns->cfun, cfuns->name, regprefix, cfuns->source_file, cfuns->source_line);
@@ -595,6 +612,7 @@ void janet_cfuns_prefix(JanetTable *env, const char *regprefix, const JanetReg *
     NameBuf nb;
     if (env) namebuf_init(&nb, regprefix);
     while (cfuns->name) {
+        janet_check_pointer_align(cfuns->cfun);
         Janet fun = janet_wrap_cfunction(cfuns->cfun);
         if (env) janet_def(env, namebuf_name(&nb, cfuns->name), fun, cfuns->documentation);
         janet_registry_put(cfuns->cfun, cfuns->name, regprefix, NULL, 0);
@@ -607,6 +625,7 @@ void janet_cfuns_ext_prefix(JanetTable *env, const char *regprefix, const JanetR
     NameBuf nb;
     if (env) namebuf_init(&nb, regprefix);
     while (cfuns->name) {
+        janet_check_pointer_align(cfuns->cfun);
         Janet fun = janet_wrap_cfunction(cfuns->cfun);
         if (env) janet_def_sm(env, namebuf_name(&nb, cfuns->name), fun, cfuns->documentation, cfuns->source_file, cfuns->source_line);
         janet_registry_put(cfuns->cfun, cfuns->name, regprefix, cfuns->source_file, cfuns->source_line);
@@ -623,6 +642,7 @@ void janet_register(const char *name, JanetCFunction cfun) {
 /* Abstract type introspection */
 
 void janet_register_abstract_type(const JanetAbstractType *at) {
+    janet_check_pointer_align((void *) at);
     Janet sym = janet_csymbolv(at->name);
     Janet check = janet_table_get(janet_vm.abstract_registry, sym);
     if (!janet_checktype(check, JANET_NIL) && at != janet_unwrap_pointer(check)) {
@@ -655,6 +675,7 @@ void janet_core_def_sm(JanetTable *env, const char *name, Janet x, const void *p
 void janet_core_cfuns_ext(JanetTable *env, const char *regprefix, const JanetRegExt *cfuns) {
     (void) regprefix;
     while (cfuns->name) {
+        janet_check_pointer_align(cfuns->cfun);
         Janet fun = janet_wrap_cfunction(cfuns->cfun);
         janet_table_put(env, janet_csymbolv(cfuns->name), fun);
         janet_registry_put(cfuns->cfun, cfuns->name, regprefix, cfuns->source_file, cfuns->source_line);

src/core/wrap.c

@@ -194,12 +194,18 @@ Janet janet_wrap_number_safe(double d) {
 
 void *janet_nanbox_to_pointer(Janet x) {
     x.i64 &= JANET_NANBOX_PAYLOADBITS;
+    x.u64 <<= JANET_NANBOX_64_POINTER_SHIFT; /* Alignment, usually 0 */
     return x.pointer;
 }
 
 Janet janet_nanbox_from_pointer(void *p, uint64_t tagmask) {
     Janet ret;
     ret.pointer = p;
+    /* Should be noop when pointer shift is 0 */
+    /*
+    janet_assert(!(ret.u64 & (uint64_t) ((1 << JANET_NANBOX_64_POINTER_SHIFT) - 1)), "unaligned pointer wrap");
+    */
+    ret.u64 >>= JANET_NANBOX_64_POINTER_SHIFT; /* Alignment, usually 0 */
     ret.u64 |= tagmask;
     return ret;
 }
@@ -207,6 +213,11 @@ Janet janet_nanbox_from_pointer(void *p, uint64_t tagmask) {
 Janet janet_nanbox_from_cpointer(const void *p, uint64_t tagmask) {
     Janet ret;
     ret.pointer = (void *)p;
+    /* Should be noop when pointer shift is 0 */
+    /*
+    janet_assert(!(ret.u64 & (uint64_t) ((1 << JANET_NANBOX_64_POINTER_SHIFT) - 1)), "unaligned pointer wrap");
+    */
+    ret.u64 >>= JANET_NANBOX_64_POINTER_SHIFT; /* Alignment, usually 0 */
     ret.u64 |= tagmask;
     return ret;
 }

src/include/janet.h

@@ -307,25 +307,38 @@ extern "C" {
  * architectures (Nanboxing only tested on x86 and x64), comment out
  * the JANET_NANBOX define.*/
 
-#if defined(_M_ARM64) || defined(_M_ARM) || defined(__aarch64__)
-#define JANET_NO_NANBOX
-#endif
-
 #ifndef JANET_NO_NANBOX
 #ifdef JANET_32
 #define JANET_NANBOX_32
-#elif defined(__x86_64__) || defined(_WIN64) || defined(__riscv)
+#elif defined(__x86_64__) || defined(_WIN64) || defined(__riscv) || defined(__aarch64__) || defined(_M_ARM64)
 /* We will only enable nanboxing by default on 64 bit systems
- * for x64 and risc-v. This is mainly because the approach is tied to the
+ * for x64, risc-v, and arm64. This is mainly because the approach is tied to the
  * implicit 47 bit address space. Many arches allow/require this, but not all,
- * and it requires cooperation from the OS. ARM should also work in many configurations. */
+ * and it requires cooperation from the OS. ARM should also work in many configurations by taking advantage
+ * of pointer alignment to allow for 48 or 49 bits of address space. */
 #define JANET_NANBOX_64
+
+/* Allow 64-bit nanboxing to assume aligned pointers to get back some extra bits for representation.
+ * This is needed to use nanboxing on systems with larger than 47-bit address spaces, such as many
+ * aarch64 systems. */
+#ifndef JANET_NANBOX_64_POINTER_SHIFT
+#if (defined(_M_ARM64) || defined(__aarch64__)) && !defined(JANET_APPLE)
+/* All pointers, including function pointers, should be 4-byte aligned on aarch64 by default.
+ * The exception is aarch64 macos, as it uses the same 47-bit userland address-space as on amd64. */
+#define JANET_NANBOX_64_POINTER_SHIFT 0 /* TODO - set me back to 2! (trying to trigger crash) */
 #endif
 #endif
+#endif
+#endif
+
+/* Allow for custom pointer alignment as well */
+#if defined(JANET_NANBOX_64) && !defined(JANET_NANBOX_64_POINTER_SHIFT)
+#define JANET_NANBOX_64_POINTER_SHIFT 0
+#endif
 
 /* Runtime config constants */
 #ifdef JANET_NO_NANBOX
-#define JANET_NANBOX_BIT 0
+#define JANET_NANBOX_BIT 0x0
 #else
 #define JANET_NANBOX_BIT 0x1
 #endif
@@ -336,9 +349,16 @@ extern "C" {
 #define JANET_SINGLE_THREADED_BIT 0
 #endif
 
+#ifdef JANET_NANBOX_64_POINTER_SHIFT
+#define JANET_NANBOX_POINTER_SHIFT_BITS (JANET_NANBOX_64_POINTER_SHIFT ? (0x4 << JANET_NANBOX_64_POINTER_SHIFT) : 0)
+#else
+#define JANET_NANBOX_POINTER_SHIFT_BITS 0
+#endif
+
 #define JANET_CURRENT_CONFIG_BITS \
     (JANET_SINGLE_THREADED_BIT | \
-     JANET_NANBOX_BIT)
+     JANET_NANBOX_BIT | \
+     JANET_NANBOX_POINTER_SHIFT_BITS)
 
 /* Represents the settings used to compile Janet, as well as the version */
 typedef struct {
@@ -1415,7 +1435,7 @@ enum JanetOpCode {
 };
 
 /* Info about all instructions */
-extern enum JanetInstructionType janet_instructions[JOP_INSTRUCTION_COUNT];
+extern const enum JanetInstructionType janet_instructions[JOP_INSTRUCTION_COUNT];
 
 /***** END SECTION OPCODES *****/
 
@@ -2063,8 +2083,14 @@ JANET_API Janet janet_resolve_core(const char *name);
  *
  * */
 
+#if defined(JANET_NANBOX_64) && (JANET_NANBOX_64_POINTER_SHIFT != 0) && !defined(JANET_MSVC)
+#define JANET_CFUNCTION_ALIGN __attribute__((aligned(1 << JANET_NANBOX_64_POINTER_SHIFT)))
+#else
+#define JANET_CFUNCTION_ALIGN
+#endif
+
 /* Shorthand for janet C function declarations */
-#define JANET_CFUN(name) Janet name (int32_t argc, Janet *argv)
+#define JANET_CFUN(name) JANET_CFUNCTION_ALIGN Janet name (int32_t argc, Janet *argv)
 
 /* Declare a C function with documentation and source mapping */
 #define JANET_REG_END {NULL, NULL, NULL, NULL, 0}
@@ -2080,7 +2106,7 @@ JANET_API Janet janet_resolve_core(const char *name);
 #define JANET_REG_S(JNAME, CNAME) {JNAME, CNAME, NULL, __FILE__, CNAME##_sourceline_}
 #define JANET_FN_S(CNAME, USAGE, DOCSTRING) \
     static const int32_t CNAME##_sourceline_ = __LINE__; \
-    Janet CNAME (int32_t argc, Janet *argv)
+    Janet JANET_CFUNCTION_ALIGN CNAME (int32_t argc, Janet *argv)
 #define JANET_DEF_S(ENV, JNAME, VAL, DOC) \
     janet_def_sm(ENV, JNAME, VAL, NULL, __FILE__, __LINE__)
 
@@ -2088,7 +2114,7 @@ JANET_API Janet janet_resolve_core(const char *name);
 #define JANET_REG_D(JNAME, CNAME) {JNAME, CNAME, CNAME##_docstring_, NULL, 0}
 #define JANET_FN_D(CNAME, USAGE, DOCSTRING) \
     static const char CNAME##_docstring_[] = USAGE "\n\n" DOCSTRING; \
-    Janet CNAME (int32_t argc, Janet *argv)
+    Janet JANET_CFUNCTION_ALIGN CNAME (int32_t argc, Janet *argv)
 #define JANET_DEF_D(ENV, JNAME, VAL, DOC) \
     janet_def(ENV, JNAME, VAL, DOC)
 
@@ -2097,7 +2123,7 @@ JANET_API Janet janet_resolve_core(const char *name);
 #define JANET_FN_SD(CNAME, USAGE, DOCSTRING) \
     static const int32_t CNAME##_sourceline_ = __LINE__; \
     static const char CNAME##_docstring_[] = USAGE "\n\n" DOCSTRING; \
-    Janet CNAME (int32_t argc, Janet *argv)
+    Janet JANET_CFUNCTION_ALIGN CNAME (int32_t argc, Janet *argv)
 #define JANET_DEF_SD(ENV, JNAME, VAL, DOC) \
     janet_def_sm(ENV, JNAME, VAL, DOC, __FILE__, __LINE__)