Run build/build clangd to generate a compile_commands.json file which clangd will use to resolve the flags CBQN expects. Other build/build flags will also be respected, e.g. build/build replxx singeli native clangd will result in clangd assuming the SINGELI and USE_REPLXX macros are defined, and will resolve generated Singeli sources to ones build/build replxx singeli native generates (along with everything else the configurations change).
(depending on the LSP in use, you may need to restart the LSP/clangd/editor after a modified compile_commands.json)
Functions starting with m_ makes a new object (some NaN-boxed, some heap-allocated).
Functions starting with q_ are queries/predicates, and return a boolean.
Functions ending with R are either supposed to be called rarely, or the caller expects that a part of it happens rarely.
Functions ending with N are non-inlined versions of another function.
Functions ending with F are infrequently needed fallback parts of a function.
Functions ending with P (or sometimes containing p or P) take a pointer argument (as opposed to a (NaN-boxed) B).
Functions ending with U return (or take) a non-owned object (U = "unincremented").
Functions ending with _c1 are monadic implementations, _c2 are dyadic (see builtin implementations)
Functions ending with G can only be called with some guarantee (e.g. argument is heap-allocated, or fits in some type, etc).
Variables starting with bi_ are builtins (primitives or special values).
Which arguments are consumed usually is described in a comment after the function or its prototype. Otherwise, check the source.
src/
builtins/
sfns.c structural functions
fns.c other functions
arithd.c dyadic arithmetic functions
arithm.c monadic arithmetic functions (incl •math stuff)
cmp.c dyadic comparison functions
md1.c 1-modifiers
md2.c 2-modifiers
sysfn.c •-definitions
utils/ utilities included as needed
file.h file system operations
hash.h hashing things
mut.h temporary mutable array operations
talloc.h temporary buffer allocations (described more below)
utf.h UTF-8 things
opt/ files which aren't needed for every build configuration
gen/ generated files
jit/ simple JIT compiler for x86-64
core/ things included everywhere
h.h core CBQN definitions
builtins.h definitions of all built-in functions (excluding things defined by means of nfns.c)
core.h file imported everywhere that defines the base BQN model
nfns.c native functions for things that need to keep some state (e.g. •FLines needs to also hold the path its relative to)
load.c loads the self-hosted compiler, runtime and formatter, initializes CBQN globals
main.c main function & commandline stuff
ns.c namespaces
vm.c virtual machine interpreter
)
c1,c2inh.h- correspondingly monadically or dyadically invoke a functionevalBCinvm.c- VM bytecode interpreterslash_c2inbuiltins/slash.c- implementation of𝕨/𝕩- See
load.cfruntimeitems for more builtins (remove leadingbi_& append_c1/_c2to get the implementation function) load_initinload.c- loads the BQN runtime & compilerbqn_compinload.c- execute BQN code from a stringBN(allocL)inopt/mm_buddyTemplate.h- fast path of buddy memory allocator; invoked fromopt/mm_buddy.hbuiltins/arithd.c- dyadic pervasive builtins- non-Singeli
÷√⋆|:GC2f;×∧∨⌊⌈+-array F array:AR_I_AA, atom F array:AR_I_SA - Singeli: implementations in
src/singeli/src/dyarith.singeli, requirements/tables generated bysrc/singeli/src/genArithTables.bqn
- non-Singeli
B, a 64-bit NaN-boxed value, represents any BQN object. Some of the NaN-boxed types, determined by the top 16 bits, are heap-allocated (i.e. low 48 bits are a Value*), some aren't. The heap-allocated ones are reference-counted.
Type checks (all are safe to execute on any B object):
test tag description heap-allocated
isF64(x) N/A a number no
isC32(x) C32_TAG a character no
isAtm(x) [many] !isArr(x) depends
isVal(x) [many] heap-allocated yes
isArr(x) ARR_TAG an array type yes
isFun(x) FUN_TAG a function yes
isMd1(x) MD1_TAG a 1-modifier yes
isMd2(x) MD2_TAG a 2-modifier yes
isMd (x) [many] any modifier yes
isCallable(x) [many] isFun|isMd yes
isNsp(x) NSP_TAG a namespace yes
isObj(x) OBJ_TAG internal yes
and then there are some extra types for variable slot references for the VM & whatever; see h.h *_TAG definitions
tag(x,*_TAG) // pointer → B
taga(x) // pointer → array B; == tag(x, ARR_TAG)
Functions for converting/using atom types:
m_f64(x) // f64 → B
m_c32(x) // codepoint → B
m_i32(x) // i32 → B
m_usz(x) // usz → B
// convert B to an atom type (first one errors on invalid, second assumes the conversion is doable losslessly):
o2b(x) o2bG(x) // bool
o2i(x) o2iG(x) // i32
o2c(x) o2cG(x) // c32
o2s(x) o2sG(x) // usz
o2f(x) o2fG(x) // f64
o2i64(x) o2i64G(x) // i64
o2u64(x) o2u64G(x) // u64
// test if f64 or B fit in a specified type:
q_fbit(x) q_bit(x)
q_fi8(x) q_i8(x)
q_fi16(x) q_i16(x)
q_fi32(x) q_i32(x)
q_fi64(x) q_i64(x)
q_fu64(x) q_u64(x)
q_fusz(x) q_usz(x)
q_N(x) // query if x is · (≡ bi_N)
noFill(x) // query if x represents undefined fill (which returned by getFill*; aka test if equal to bi_noFill)
type field for heap-allocated objects:
// note that this is distinct from the tag; use TY(x) / PTY(x) to read this field
t_empty // empty bucket; EmptyValue
t_funBI, t_md1BI, t_md2BI // function/1-modifier/2-modifier builtins; BFn, BMd1, BMd2
t_funBl, t_md1Bl, t_md2Bl // function/1-modifier/2-modifier blocks; FunBlock, Md1Block, Md2Block
t_shape // shape object
t_fork, t_atop // (F G H), (F G); Fork, Atop
t_md1D, t_md2D // (F _m), (F _m_ G); Md1D, Md2D
t_harr // array with generic items and no fill; HArr
t_fillarr // array with generic items and a fill; FillArr
t_bitarr, t_i8arr, t_i16arr, t_i32arr, t_c8arr, t_c16arr, t_c32arr, t_f64arr // arrays with typed elements; TyArr
t_hslice, t_fillslice, t_i8slice, t_i16slice, t_i32slice, t_c8slice, t_c16slice, t_c32slice, t_f64slice // slice types of the above (except bitarr!); Slice, TySlice, HSlice, FillSlice
t_mmapH // mmap-ped data; MmapHolder
t_harrPartial // partially-written HArr
t_comp, t_block, t_body, t_scope, t_scopeExt, t_blBlocks // various compiled object things; see vm.h/vm.c
t_fldAlias, t_arrMerge, t_vfyObj // various mutation target data holders; see vm.h/vm.c
t_ns, t_nsDesc // namespace, namespace descriptor; NS, NSDesc
t_nfn, t_nfnDesc // native function, native function descriptor; NFn/NFnDesc
t_ffiType // FFI data object; BQNFFIType
t_customObj // type with dynamic visit & free methods; CustomObj
t_arbObj // generic arbitrary heap-allocated object
t_talloc, t_temp // temporary allocation types; multiple uses
t_hashmap // hashmap
t_freed // object mid-freeing during GC
t_invalid // placeholder type for places where a type shouldn't be
t_funWrap, t_md1Wrap, t_md2Wrap // types wrapping builtins for RT_WRAP; see rtwrap.c
See src/h.h for more basic operationsAn object can be allocated with mm_alloc(sizeInBytes, t_something). The returned object starts with the structure of Value, so custom data must be after that. mm_free can be used to force-free a heap-allocated object regardless of its reference count.
Any such allocation is guaranteed to have at least 1024 bytes readable & writable both before & after the allocation, though of course the read values should not affect any visible behavior, and writes need to write back exactly the data that was there before.
A heap-allocated object from type B can be cast to a Value* with v(x), to an Arr* with a(x), or to a specific pointer type with c(Type,x).
The reference count of any B object can be incremented/decremented with inc(x)/dec(x), and any subtype of Value* can use ptr_inc(x)/ptr_dec(x). inc(x) and ptr_inc(x) will return the argument, so you can use it inline. dec(x) and ptr_dec(x) will free the object if the refcount as a result goes to zero. incBy / incByG offset the reference count by the specified amount, but will not free the object if it results in a reference count of zero.
Since reference counting is hard, there's make heapverify that verifies that any code executed does it right (and screams unreadable messages when it doesn't). After any changes, I'd suggest running test/mainCfgs.sh path/to/mlochbaum/BQN, which'll run a couple primary configurations, including said heapverify.
Temporary allocations can be made with utils/talloc.h:
#include "utils/talloc.h"
TALLOC(char, buf, 123); // allocate char* buf with 123 elements
char* buf = TALLOCP(char, 123); // alternative syntax, useful if buf is declared elsewhere
// buf is now a regular char* and can be stored/passed around as needed
buf = TREALLOC(buf, 456); // extend buf; may reuse, may allocate new space; won't ever truncate
TFREE(buf); // free buf
// if the size is guaranteed to be small enough, using VLAs is potentially fine
// but even a rank-sized buffer is probably better off in a TALLOC (if impossible to write directly in a shape ahead-of-time)
TSALLOC(i32, stack, 10); // allocate an i32 stack with initially reserved 10 items (initial reserve must be positive!)
TSADD(stack, 15); // add a single item
TSADDA(stack, (i32*){1,2,3}, 3); // add many items
usz sz = TSSIZE(stack); // get the current height of the stack
i32 item = stack[1]; // get the 2nd item
TSFREE(stack); // free the stack
// note that TSALLOC creates multiple local variables, and as such cannot be passed around to other functionsAll virtual method accesses require that the argument is heap-allocated.
You can get a virtual function of a B object with TI(x, something). There's also TIv(x, something) for a pointer x instead. See #define FOR_TI in src/h.h for available functions.
Call a BQN function object with c1(f, x) or c2(f, w, x). A specific builtin can be called by looking up the appropriate name in src/builtins.h, adding the bi_ prefix, and invoking it with c1/c2. Note that these functions consume w and x, but leave the refcount of f untouched. (usually, which arguments are consumed is specified in a comment after either the function definition or prototype)
Calling a modifier involves deriving it with m1_d/m2_d, using a regular c1/c2, and managing the refcounts of everything while at that.
The list of builtin functions is specified in the initial macros of src/builtins.h, where A/M/D are used for ambivalent/monadic/dyadic. Once added, bi_yourName will be available, and the required of the following functions must be defined somewhere in the source:
// functions:
B yourName_c1(B t, B x);
B yourName_c2(B t, B w, B x);
// 1-modifiers:
B yourName_c1(Md1D* d, B x);
B yourName_c2(Md1D* d, B w, B x);
// 2-modifiers:
B yourName_c1(Md2D* d, B x);
B yourName_c2(Md2D* d, B w, B x);For functions, in most cases, the t parameter (representing 𝕊/"this") is unused (it must be ignored for functions managed by builtins.h), but can be used for objects from nfns.h to store state with a function.
For modifiers, the d parameter stores the operands and the modifier itself. Use d->f for 𝔽, d->g for 𝔾, d->m1 for _𝕣, d->m2 for _𝕣_, and tag(d,FUN_TAG) for 𝕊.
The implementation should consume the w/x arguments, but not t/d.
// im - monadic inverse
// ix - 𝕩-inverse - w⊸F⁼ x aka w F⁼ x
// iw - 𝕨-inverse - F⟜x⁼ w
// the calls for these must be in some `whatever_init()` function, and apply only to builtins specified in builtins.h
c(BFn,bi_someFunction)->im = someFunction_im; // set the monadic inverse; someFunction_im has the signature of a regular monadic call implementation
c(BFn,bi_someFunction)->ix = someFunction_ix; // etc
c(BFn,bi_someFunction)->iw = someFunction_iw;
c(BMd1,bi_some1mod)->ix = some1mod_ix;
c(BMd2,bi_some2mod)->im = some2mod_im; // you get the idea
// for new types, the appropriate virtual functions (fn_im/fn_is/fn_iw/fn_ix/m1_im/m1_iw/m1_ix/m2_im/m2_iw/m2_ix) can be setThere exist various macros to view the main metadata of an array:
| operation | B x; |
Value* x / Arr* x / etc |
result type |
|---|---|---|---|
| get shape | SH(x) |
PSH(x) |
usz* |
| get item amount (product of shape) | IA(x) |
PIA(x) |
usz |
| get rank | RNK(x) |
PRNK(x) |
ur |
| set rank | SRNK(x) |
SPRNK(x) |
N/A |
The shape pointer of a rank≤1 array will point to the object's own ia field (the one read by IA(x)). Otherwise, it'll point within a reference-counted t_shape object (ShArr's a field).
Allocating an array:
i32* rp; B r = m_i32arrv(&rp, 123); // allocate a 123-element i32 vector
i32* rp; B r = m_i32arrc(&rp, x); // allocate an array with the same shape as x (x must be an array; x isn't consumed)
i32* rp; Arr* r = m_i32arrp(&rp, 123); // allocate a 123-element i32-array without allocating shape
// then at some point do one of these:
arr_shVec(r); // set shape of r to a vector
usz* sh = arr_shAlloc(r, 4); // allocate a rank 4 shape; write to sh the individual items; sh will be NULL for ranks 0 and 1
arr_shCopy(r, x); // copy the shape object of x (doesn't consume x)
// then get the final array:
B result = taga(r);
// see stuff.h for m_shArr/arr_shSet* for ways to batch-assign a single shape object to multiple objects
u32* rp; B r = m_c32arrv(%rp, 10); // 10-char string
// etc for m_(i8|i16|i32|c8|c16|c32|f64)arr[vcp]
// arbitrary object arrays:
// initialized with all elements being 0.0s, which you can replace with `r.a[i]=val`, and get the result with `r.b`; simple, but may not be optimal
HArr_p r = m_harr0v(10); // new 10-item vector
HArr_p r = m_harr0c(10, x); // new 10-item array with the same shape as x
HArr_p r = m_harr0p(10); // new 10-item array without any set shape. Use the arr_shWhatever(r.c, …)
// safe known size array creation without preinitialization:
M_HARR(r, 123) // allocate a 123-item arbitrary object array
HARR_ADD(r, i, val); // write val to the next position in the array. The 'i' variable is just a hint, all calls must be consecutive either way
HARR_ADDA(r, val); // the above but without needing the useless 'i' parameter
// then do one of these to get the finished object:
B result = HARR_FV(r); // sets shape to a vector
B result = HARR_FC(r, x); // copies the shape of x, doesn't consume x
B result = HARR_FCD(r, x); // copies the shape of x and consumes it
usz* sh = HARR_FA(r, 4); // allocate shape for a rank 4 array. To get the result `B` object, do HARR_O(r).b later
Arr* result = HARR_FP(r); // don't allocate/set any shape
// If at any point you want to free the object before finishing it, do HARR_ABANDON(r)
// If you're sure GC cannot happen (that includes no allocating) before all items in the array are set, you can use:
HArr_p r = m_harrUv(10); // 10-item vector
HArr_p r = m_harrUc(10, x); // 10-item array with the same shape as x
HArr_p r = m_harrUp(10); // 10-item array without any set shape. Use the arr_shWhatever(r.c, …)
// run `NOGC_E;` after filling in the items to resume allowing allocations (not necessary if item count is 0)
// you can use withFill to add a fill element to a created array (or manually create a fillarr, see src/core/fillarr.h)
B r = m_c32vec(U"⟨1⋄2⋄3⟩", 7); // a constant string with unicode chars
B r = m_c32vec_0(U"⟨1⋄2⋄3⟩"); // ..or with implicit length
B r = m_c8vec("hello", 5); // a constant ASCII string
B r = m_c8vec_0("hello"); // ..or with implicit length
B r = utf8Decode("⟨1⋄2⋄3⟩", 17) // decode UTF-8 from a char*
B r = utf8Decode0("⟨1⋄2⋄3⟩") // ..or with implicit length
#include "utils/utf.h"
u64 sz = utf8lenB(x); TALLOC(char, buf, sz+1); toUTF8(x, buf); buf[sz]=0; /*use buf as a C-string*/ TFREE(buf);
// src/utils/mut.h provides a way to build an array by copying parts of other arrays
// some functions for making specific arrays:
B r = m_unit(x); // equivalent to <𝕩
B r = m_hunit(x); // like the above, except no fill is set
B r = m_atomUnit(x); // if x is likely to be an atom, this is a better alternative to m_unit
B r = m_hVec1(a); // ⟨a⟩
B r = m_hVec2(a,b); // ⟨a,b⟩
B r = m_hVec3(a,b,c); // ⟨a,b,c⟩
B r = m_hVec4(a,b,c,d); // ⟨a,b,c,d⟩
B r = emptyHVec(); // an empty vector with no fill
B r = emptyIVec(); // an empty integer vector
B r = emptyCVec(); // an empty character vector
B r = emptySVec(); // an empty string vectorRetrieving data from arrays:
// generic methods:
SGet(x) // initializes the getter for fast reads; the argument must be a variable name
B c = Get(x,n); // in a loop, reading the n-th item
SGetU(x)
B c = GetU(x,n); // alternatively, GetU can be used to not increment the result. Useful for temporary usage of the item or if it is known to not be heap-allocated (or code throws an error if it is)
B c = IGet(x,n); // skip the initialize/call separation; not suggested in loops
B c = IGetU(x,n);
// for specific array types:
if (TI(x,elType)==el_i32) i32* xp = i32any_ptr(x); // for either t_i32arr or t_i32slice; for t_i32arr only, there's i32arr_ptr(x); same for all other primitive element types (except bitarr which only has bitarr_ptr)
if (TI(x,elType)!=el_B) void* xp = tyany_ptr(x); // alternative equivalent check: IS_ANY_ARR(TY(x)); tyarr_ptr if the input is also known to not be a slice
if (TY(x)==t_harr) B* xp = harr_ptr(x);
if (TY(x)==t_harr || TY(x)==t_hslice) B* xp = hany_ptr(x); // note that elType==el_B doesn't imply hany_ptr is safe!
if (TY(x)==t_fillarr) B* xp = fillarr_ptr(x);
B* xp = arr_bptr(x); // will return NULL if the array isn't backed by a contiguous B*
// functions to convert arrays to a specific type array: (all consume their argument, and assume that the elements losslessly fit in the desired type)
I8Arr* a = toI8Arr(x); // convert x to an I8Arr instance (returns the argument if it already is)
I8Arr* a = (I8Arr*)cpyI8Arr(x); // get an I8Arr with reference count 1 with the same items & shape
B a = toI8Any(x); // get an object which be a valid argument to i8any_ptr
// same logic applies for:
// toBitArr/toI8Arr/toI16Arr/toI32Arr/toF64Arr/toC8Arr/toC16Arr/toC32Arr/toHArr
// cpyBitArr/cpyI8Arr/cpyI16Arr/cpyI32Arr/cpyF64Arr/cpyC8Arr/cpyC16Arr/cpyC32Arr/cpyHArr
// toI8Any/toI16Any/toI32Any/toF64Any/toC8Any/toC16Any/toC32AnyThrow an error with thrM("some message") or thr(some B object) or thrOOM(). Leaving reference counts at a higher-than-necessary reference count is acceptable.
A fancier message can be created with thrF(message, …) with printf-like (but different!!) varargs (source in do_fmt):
%i decimal i32 (also for i8/i16/ur)
%l decimal i64
%ui decimal u32 (also for u8/u16)
%ul decimal u64
%xi hex u32
%xl hex u64
%s decimal usz
%f f64
%p pointer
%c unicode character (u32)
%S char* C-string consisting of ASCII
%U char* of UTF-8 data
%R a B object of a number or string (string is printed without quotes or escaping)
%H the shape of a B object
%2H a shape, passed in by a ur & usz*
%B a B object, formatted by •Repr (be very very careful to not give a potentially large object, which'd lead to unreadably long messages!)
%% "%"
See #define CATCH in src/h.h for how to catch errors.
Use assert(predicate) for checks (for optimized builds they're replaced with if (!predicate) invoke_undefined_behavior(); so it's still invoked!!). UD; can be used to explicitly invoke undefined behavior (equivalent in behavior to assert(false);), which is useful for things like untaken default branches in switch statements.
There's also fatal("message") that (at least currently) is kept in optimized builds as-is, and always kills the process on being called.
The garbage collector can run either at the top level (currently, between lines of REPL input) at full capability, where all unreferenced objects will be freed, or potentially during any allocation in a severely restricted mode where any object with a reference count not matching the expected value is assumed as a GC root (intention being that it's referred to by live code on the C stack, but it could also be a leak if an error left reference counts too high).
Therefore, at any point of execution where an allocation or error happens, the heap must be in a valid state (that is, most allocated objects need all their pointer/object fields initialized (more precisely, anything used by the object's void [type]_visit() function (and [type]_free if the object may be GC'd))). Manually mm_allocing an object will result in an invalid initial state for most types, but higher-level allocation function helpers usually initialize them to a valid state (e.g. m_c8arrv, m_tyarrp, m_md2D, m_scope, m_harr0p, m_fillarr0p, m_fillarrpEmpty), but some do not (e.g. m_harrUv, m_fillarrp); those will need a NOGC_E; statement to be added after you've initialized them (and be careful to do that only when actually done - the debugging options for a GC during an incompletely-initialized heap aren't nice!)
To add a permanent GC root, use gc_add(B x). To add dynamic roots, the options are gc_add_ref(B* x), which checks & uses *x as a GC root, or gc_addFn(vfn f), where the given function should invoke mm_visit or mm_visitP on the objects it wants to assume as roots. gc_add and gc_add_ref and mm_visit accept non-heap-allocated values (i.e. numbers, characters, bi_N), but mm_visitP must not be passed the null pointer.
A couple functions for simple actions within GDB/LLDB are defined:
void g_pst() // print a BQN stacktrace; might not work if paused in the middle of stackframe manipulation, but it tries
void g_p(B x) // print x
void g_i(B x) // print •internal.Info x
void g_pv(Value* x) // g_p but for an untagged value
void g_iv(Value* x) // g_i but for an untagged value
Value* g_v(B x) // untag a value
Arr* g_a(B x) // untag a value to Arr*
B g_t (void* x) // tag pointer with OBJ_TAG
B g_ta(void* x) // tag pointer with ARR_TAG
B g_tf(void* x) // tag pointer with FUN_TAG
// invoke with "p g_p(whatever)"; requires a build with debug symbols for best experience, but e.g. "p (void)g_pst()" can be used without oneMost toggles require a value of 1 to be enabled.
// (effective) usual default value is listed; (u) marks being not defined
// defaults may change under some conditions (DEBUG, USE_SETJMP, heapverify, among maybe other things)
// some things fully configured by the build system may not be listed
// general config:
#define REPL_INTERRUPT 0 // support ctrl+c for interrupting some REPL execution
#define ENABLE_GC 1 // enable garbage collection
#define MM 1 // memory manager; 0 - malloc (no GC); 1 - buddy; 2 - 2buddy
#define HEAP_MAX ~0ULL // initial heap max size (overridden by -M)
#define JIT_ENABLED (u) // force-enable or force-disable JIT (x86_64-only)
#define RANDSEED 0 // random seed used to make •rand (0 uses time)
#define JIT_START 2 // number of calls for when to start JITting (x86_64-only); default is 2, defined in vm.h
// -1: never JIT (≈ JIT_ENABLED=0)
// 0: JIT everything
// >0: JIT after n non-JIT invocations; max ¯1+2⋆16
// runtime configuration:
#define ALL_R0 0 // use all of r0.bqn for runtime_0
#define ALL_R1 0 // use all of r1.bqn for runtime
#define NO_RT 0 // whether to completely disable self-hosted runtime loading
#define FAKE_RUNTIME 0 // disable the self-hosted runtime
#define FORMATTER 1 // use self-hosted formatter for output
#define NO_EXPLAIN 0 // disable )explain
#define NO_RYU 0 // disable usage of Ryu
#define EACH_FILLS 0 // compute fills for ¨ and ⌜; may be forcibly disabled
#define SFNS_FILLS 1 // compute fills for structural functions (∾, ≍, etc)
#define CHECK_VALID 1 // check for valid arguments in places where that would be detrimental to performance
// e.g. left argument sortedness of ⍋/⍒, incompatible changes in ⌾, etc
#define USE_SETJMP 1 // whether setjmp is available & should be used for error catching (makes refcounts leakable)
#define SEMANTIC_CATCH USE_SETJMP // whether catching should be assumed to be usable for operations which need to semantically change depending on that
#define SEMANTIC_CATCH_BI SEMANTIC_CATCH // whether ⎊ will catch stuff
#define RYU_OPTIMIZE_SIZE 0 // reduce size of Ryu tables at the cost of some performance for number •Repr
#define FFI_CHECKS 1 // check for valid arguments passed to FFI-d functions
#define UNSAFE_SIZES 0 // disable safety checks on array length overflows
// debugging stuff:
#define DEBUG 0 // the regular debug build
#define HEAP_VERIFY 0 // heapverify
#define RT_VERIFY 0 // compare native and runtime versions of primitives
#define WARN_SLOW 0 // log on various slow operations
#define USE_PERF 0 // write a /tmp/perf-<pid>.map for JITted things for linux perf
#define GC_LOG_DETAILED 0 // slightly more stats on GC logging
#define DEBUG_VM 0 // print evaluation of every bytecode
#define USE_VALGRIND 0 // adjust memory manager & code for valgrind usage
#define VERIFY_TAIL (u) // number of bytes after the end of an array to verify not being improperly modified; 64 in DEBUG
#define NEEQUAL_NEGZERO 0 // make negative zero not equal zero for •internal.EEqual
#define RT_VERIFY_ARGS 1 // rtverify: preserve arguments for printing on failure
#define GC_EVERY_NTH_ALLOC (u) // force a GC on every n'th allocation (<=1 to GC on every alloc)
// some somewhat-outdated/unmaintained things:
#define RT_PERF 0 // time runtime primitives
#define ALLOC_STAT 0 // store basic allocation statistics
#define ALLOC_SIZES 0 // store per-type allocation size statistics
#define DONT_FREE 0 // don't actually ever free objects, such that they can be printed after being freed for debugging
#define TYPED_ARITH 1 // enable specialized loops for typed arith
#define VM_POS 1 // whether to store detailed execution position information for stacktraces
#define OBJ_COUNTER 0 // store a unique allocation number with each object; superseded by the existence of https://rr-project.org/
#define OBJ_TRACK (u) // object ID to track