Hi, something like this should work:

RUNTIME_FUNCTION(...) {
 ...
 return *isolate->factory()->NewNumber(number);
}
On Tue, Feb 14, 2023 at 8:19 PM Pradyumna Shome <pradyumna.sh...@gmail.com>
wrote:

> Hi all
>
> I'm trying to add a new runtime function to return the Data Pointer of an
> array as a v8::NumberObject, so I can operate upon memory addresses in
> other JavaScript commands. I'm having trouble constructing and returning an
> object of type v8::internal::Object, since it seems like every operation
> always returns a Local/Handle.
>
> I reached out to one of the developers (Jakob) separately, and they
> pointed me to the definition of v8::NumberObject::New
> <https://source.chromium.org/chromium/chromium/src/+/main:v8/src/api/api.cc;l=7636;drc=e14364652369744ed1a8b9c4a582f11833b35aff>.
> However, I'm unable to figure out the plumbing required to satisfy the
> compiler that what I'm returning from the runtime function is indeed a
> v8::internal::Object. I've shared what I've tried doing to troubleshoot,
> the error log (bolding the actual errors) and code snippet below.
>
> Best
> Pradyumna
>
> *What I've Tried*
>
>    1. Constructing v8::StringObjects, v8::NumberObjects, and
>    v8::internal::Numbers,by plumbing together APIs from
>    
> https://v8docs.nodesource.com/node-0.8/da/d56/classv8_1_1_number_object.html
>    and other sites.
>    2. Reading the relevant pieces of https://v8.dev/docs/embed to
>    understand what Local/Handle/Persistents are.
>    3. Searched for call sites of the NumberObject/StringObject/Number
>    APIs on the GitHub, Google, and You search engines to see if others have
>    tried to do something similar. It turns out not a lot of people outside of
>    the v8 developers are editing v8 (at least publicly).
>    4. Read through numbers StackOverflow questions about construction
>    v8::internal::objects, and manipulating Locals.
>    5. Searching for related keywords on this forum.
>
>
> *Error Log (for one of the attempts)*
>
> # autoninja -C out/arm64.optdebug d8
> ninja: Entering directory `out/arm64.optdebug'
> [1/11] CXX obj/v8_base_without_compiler/runtime-test.o
> FAILED: obj/v8_base_without_compiler/runtime-test.o
> ../../third_party/llvm-build/Release+Asserts/bin/clang++ -MMD -MF
> obj/v8_base_without_compiler/runtime-test.o.d -D__STDC_CONSTANT_MACROS
> -D__STDC_FORMAT_MACROS -DCR_XCODE_VERSION=1420
> -DCR_CLANG_REVISION=\"llvmorg-16-init-17653-g39da55e8-2\" -DCOMPONENT_BUILD
> -DCR_LIBCXX_REVISION=59bae40d835ae4eabaddbef781f5e3b778dd7907
> -D_LIBCPP_ENABLE_ASSERTIONS=1 -D_DEBUG -DDYNAMIC_ANNOTATIONS_ENABLED=1
> -DCPPGC_VERIFY_HEAP -DENABLE_DISASSEMBLER
> -DV8_TYPED_ARRAY_MAX_SIZE_IN_HEAP=64 -DOBJECT_PRINT -DVERIFY_HEAP
> -DV8_TRACE_MAPS -DV8_ENABLE_ALLOCATION_TIMEOUT -DV8_ENABLE_FORCE_SLOW_PATH
> -DV8_ENABLE_DOUBLE_CONST_STORE_CHECK -DV8_INTL_SUPPORT
> -DENABLE_HANDLE_ZAPPING -DV8_CODE_COMMENTS -DV8_ENABLE_DEBUG_CODE
> -DV8_ENABLE_HEAP_SNAPSHOT_VERIFY -DV8_SNAPSHOT_NATIVE_CODE_COUNTERS
> -DV8_USE_EXTERNAL_STARTUP_DATA -DV8_ATOMIC_OBJECT_FIELD_WRITES
> -DV8_ENABLE_LAZY_SOURCE_POSITIONS -DV8_SHARED_RO_HEAP
> -DV8_WIN64_UNWINDING_INFO -DV8_ENABLE_REGEXP_INTERPRETER_THREADED_DISPATCH
> -DV8_SHORT_BUILTIN_CALLS -DV8_EXTERNAL_CODE_SPACE -DV8_ENABLE_MAGLEV
> -DV8_ENABLE_TURBOFAN -DV8_ENABLE_SYSTEM_INSTRUMENTATION
> -DV8_ENABLE_WEBASSEMBLY -DV8_ALLOCATION_FOLDING
> -DV8_ALLOCATION_SITE_TRACKING -DV8_ADVANCED_BIGINT_ALGORITHMS
> -DV8_STATIC_ROOTS -DV8_USE_ZLIB -DV8_USE_LIBM_TRIG_FUNCTIONS
> -DV8_ENABLE_CHECKS -DV8_COMPRESS_POINTERS
> -DV8_COMPRESS_POINTERS_IN_SHARED_CAGE -DV8_31BIT_SMIS_ON_64BIT_ARCH
> -DV8_ENABLE_SANDBOX -DV8_DEPRECATION_WARNINGS
> -DV8_IMMINENT_DEPRECATION_WARNINGS -DCPPGC_CAGED_HEAP
> -DCPPGC_YOUNG_GENERATION -DCPPGC_POINTER_COMPRESSION
> -DCPPGC_SLIM_WRITE_BARRIER -DV8_TARGET_ARCH_ARM64 -DV8_HAVE_TARGET_OS
> -DV8_TARGET_OS_MACOS -DDEBUG -DV8_RUNTIME_CALL_STATS -DBUILDING_V8_SHARED
> -DUSING_V8_BASE_SHARED -DUSING_V8_PLATFORM_SHARED -DU_USING_ICU_NAMESPACE=0
> -DU_ENABLE_DYLOAD=0 -DUSE_CHROMIUM_ICU=1 -DU_ENABLE_TRACING=1
> -DU_ENABLE_RESOURCE_TRACING=0 -DICU_UTIL_DATA_IMPL=ICU_UTIL_DATA_FILE
> -I../.. -Igen -I../../buildtools/third_party/libc++ -I../../include
> -Igen/include -I../../third_party/icu/source/common
> -I../../third_party/icu/source/i18n -I../../third_party/zlib -Wall -Werror
> -Wextra -Wimplicit-fallthrough -Wextra-semi -Wunreachable-code-aggressive
> -Wthread-safety -Wunguarded-availability -Wno-missing-field-initializers
> -Wno-unused-parameter -Wno-psabi -Wloop-analysis
> -Wno-unneeded-internal-declaration -Wenum-compare-conditional
> -Wno-ignored-pragma-optimize -Wno-deprecated-builtins
> -Wno-bitfield-constant-conversion -Wshadow -fno-delete-null-pointer-checks
> -fno-ident -fno-strict-aliasing -fstack-protector-strong
> -fcolor-diagnostics -fmerge-all-constants
> -fcrash-diagnostics-dir=../../tools/clang/crashreports -mllvm
> -instcombine-lower-dbg-declare=0 -ffp-contract=off
> -fcomplete-member-pointers -arch arm64 -fno-global-isel -mno-outline
> -Wno-builtin-macro-redefined -D__DATE__= -D__TIME__= -D__TIMESTAMP__=
> -ffile-compilation-dir=. -no-canonical-prefixes
> -ftrivial-auto-var-init=pattern -fno-omit-frame-pointer -g2 -gdwarf-aranges
> -Xclang -debug-info-kind=limited -isysroot
> ../../../../../../Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX13.1.sdk
> -mmacos-version-min=10.13 -Wheader-hygiene -Wstring-conversion
> -Wtautological-overlap-compare -Wmissing-field-initializers
> -Wunreachable-code -Wctad-maybe-unsupported -Wno-shadow -Wshorten-64-to-32
> -O0 -fvisibility=default -Wexit-time-destructors
> -Wno-undefined-bool-conversion -Wno-tautological-undefined-compare
> -std=c++20 -Wno-trigraphs -fno-exceptions -fno-rtti -nostdinc++
> -isystem../../buildtools/third_party/libc++/trunk/include
> -isystem../../buildtools/third_party/libc++abi/trunk/include -c
> ../../src/runtime/runtime-test.cc -o
> obj/v8_base_without_compiler/runtime-test.o
>
> *../../src/runtime/runtime-test.cc:1160:57: error: cannot initialize a
> parameter of type 'Value *' with an rvalue of type 'Local<NumberObject> *'*
> return *(v8::internal::Object*)v8::NumberObject::Cast(&numberObjectLocal);
>                                                         ^~~~~~~~~~~~~~~~~~
>
> *../../include/v8-primitive-object.h:25:46: note: passing argument to
> parameter 'value' here*  V8_INLINE static NumberObject* Cast(Value*
> value) {
>                                              ^
> In file included from ../../src/runtime/runtime-test.cc:10:
> In file included from ../../include/v8-function.h:11:
> In file included from ../../include/v8-function-callback.h:8:
>
> *../../include/v8-local-handle.h:166:5: error: static assertion failed due
> to requirement 'std::is_base_of<v8::NumberObject, v8::Value>::value': type
> check*    static_assert(std::is_base_of<T, S>::value, "type check");
>     ^             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> *../../src/runtime/runtime-test.cc:1159:43: note: in instantiation of
> function template specialization
> 'v8::Local<v8::NumberObject>::Local<v8::Value>' requested here*
> Local<NumberObject> numberObjectLocal =
> v8::NumberObject::New((v8::Isolate*)isolate, number);
>                                           ^
> 2 errors generated.
> ninja: build stopped: subcommand failed.
> Error! - V8 compilation finished with errors.
>
> *Code Snippet*
> RUNTIME_FUNCTION(Runtime_AddressOfArray) {
>   SealHandleScope shs(isolate);
>   StdoutStream os;
>
>   MaybeObject maybe_object(*args.address_of_arg_at(0));
>   Object object = maybe_object.GetHeapObjectOrSmi();
>
>   void* data_pointer = JSTypedArray::cast(object).DataPtr();
>   os << "Data Pointer: " << data_pointer << std::endl;
>
>   std::string data_pointer_string;
>   std::ostringstream stream;
>   stream << data_pointer_string;
>   data_pointer_string = stream.str();
>   int number = stoi(data_pointer_string);
>
> *Local<NumberObject> numberObjectLocal =
> v8::NumberObject::New((v8::Isolate*)isolate, number);  return
> *(v8::internal::Object*)v8::NumberObject::Cast(&numberObjectLocal);*
> }
>
> --
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