[ 99% 2187/2196] CXX obj/v8/third_party/inspector_protocol/crdtp/span.o warning: unknown warning option '-Wno-nontrivial-memcall'; did you mean '-Wno-nontrivial-memaccess'? [-Wunknown-warning-option] warning: unknown warning option '-Wno-uninitialized-const-pointer'; did you mean '-Wno-uninitialized-const-reference'? [-Wunknown-warning-option] warning: unknown warning option '-Wunnecessary-virtual-specifier'; did you mean '-Wduplicate-decl-specifier'? [-Wunknown-warning-option] 3 warnings generated. [ 99% 2188/2196] CXX obj/v8/third_party/inspector_protocol/crdtp/status.o warning: unknown warning option '-Wno-nontrivial-memcall'; did you mean '-Wno-nontrivial-memaccess'? [-Wunknown-warning-option] warning: unknown warning option '-Wno-uninitialized-const-pointer'; did you mean '-Wno-uninitialized-const-reference'? [-Wunknown-warning-option] warning: unknown warning option '-Wunnecessary-virtual-specifier'; did you mean '-Wduplicate-decl-specifier'? [-Wunknown-warning-option] 3 warnings generated. [ 99% 2189/2196] CXX obj/v8/third_party/inspector_protocol/crdtp_platform/json_platform_v8.o warning: unknown warning option '-Wno-nontrivial-memcall'; did you mean '-Wno-nontrivial-memaccess'? [-Wunknown-warning-option] warning: unknown warning option '-Wno-uninitialized-const-pointer'; did you mean '-Wno-uninitialized-const-reference'? [-Wunknown-warning-option] warning: unknown warning option '-Wunnecessary-virtual-specifier'; did you mean '-Wduplicate-decl-specifier'? [-Wunknown-warning-option] 3 warnings generated. [ 99% 2190/2196] LINK ./mksnapshot c++: warning: argument unused during compilation: '--unwindlib=none' [-Wunused-command-line-argument] [ 99% 2191/2196] ACTION //v8:run_mksnapshot_default(//build/toolchain/freebsd:clang_x64) FAILED: [code=251] gen/v8/embedded.S gen/v8/snapshot.cc python3 ../../../deno-2.6.6/cargo-crates/v8-142.2.0/v8/tools/run.py ./mksnapshot --turbo_instruction_scheduling --stress-turbo-late-spilling --target_os=freebsd --target_arch=x64 --embedded_src gen/v8/embedded.S --predictable --no-use-ic --turbo-elide-frames --embedded_variant Default --random-seed 314159265 --startup_src gen/v8/snapshot.cc --no-native-code-counters --concurrent-builtin-generation --concurrent-turbofan-max-threads=0 # # Fatal process out of memory: Oilpan: CagedHeap reservation. # ==== C stack trace =============================== 0x1dcca2e3b7d3 <v8::base::debug::StackTrace::StackTrace()+0x1dcca0924013> at /wrkdirs/usr/ports/www/deno/work/target/release/gn_out/mksnapshot 0x1dcca2e3af4b <v8::platform::(anonymous namespace)::PrintStackTrace()+0x1dcca092401b> at /wrkdirs/usr/ports/www/deno/work/target/release/gn_out/mksnapshot 0x1dcca2e30228 <v8::base::FatalOOM(v8::base::OOMType, char const*)+0x1dcca0924038> at /wrkdirs/usr/ports/www/deno/work/target/release/gn_out/mksnapshot 0x1dcca0fa53f3 <v8::internal::V8::FatalProcessOutOfMemory(v8::internal::Isolate*, char const*, v8::OOMDetails const&)+0x1dcca0924073> at /wrkdirs/usr/ports/www/deno/work/target/release/gn_out/mksnapshot 0x1dcca1153a3e <v8::internal::(anonymous namespace)::GlobalFatalOutOfMemoryHandlerImpl(std::__Cr::basic_string<char, std::__Cr::char_traits<char>, std::__Cr::allocator<char>> const&, v8::SourceLocation, cppgc::internal::HeapBase*)+0x1dcca092401e> at /wrkdirs/usr/ports/www/deno/work/target/release/gn_out/mksnapshot 0x1dcca1b1d039 <cppgc::internal::FatalOutOfMemoryHandler::operator()(std::__Cr::basic_string<char, std::__Cr::char_traits<char>, std::__Cr::allocator<char>> const&, v8::SourceLocation) const+0x1dcca0924029> at /wrkdirs/usr/ports/www/deno/work/target/release/gn_out/mksnapshot 0x1dcca1b25e37 <cppgc::internal::CagedHeap::CagedHeap(v8::PageAllocator&, unsigned long)+0x1dcca0924247> at /wrkdirs/usr/ports/www/deno/work/target/release/gn_out/mksnapshot 0x1dcca1b25bc2 <cppgc::internal::CagedHeap::InitializeIfNeeded(v8::PageAllocator&, unsigned long)+0x1dcca0924042> at /wrkdirs/usr/ports/www/deno/work/target/release/gn_out/mksnapshot 0x1dcca1b1d0d1 <cppgc::InitializeProcess(v8::PageAllocator*, unsigned long)+0x1dcca0924041> at /wrkdirs/usr/ports/www/deno/work/target/release/gn_out/mksnapshot 0x1dcca0fabda0 <v8::V8::Initialize(int)+0x1dcca0924050> at /wrkdirs/usr/ports/www/deno/work/target/release/gn_out/mksnapshot 0x1dcca0fa0e06 <main+0x1dcca0924496> at /wrkdirs/usr/ports/www/deno/work/target/release/gn_out/mksnapshot 0x1dd4c7ee9e34 <__libc_start1+0x124> at /lib/libc.so.7 Return code is -5 ninja: build stopped: subcommand failed. --- stderr thread 'main' (191816) panicked at /wrkdirs/usr/ports/www/deno/work/deno-2.6.6/cargo-crates/v8-142.2.0/build.rs:1051:3: assertion failed: ninja(&gn_out_dir, maybe_env).arg(target).status().unwrap().success() stack backtrace: 0: __rustc::rust_begin_unwind 1: core::panicking::panic_fmt 2: core::panicking::panic 3: build_script_build::build_v8 4: build_script_build::main note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace. *** Error code 101 Stop. make: stopped in /usr/ports/www/deno =>> Cleaning up wrkdir ===> Cleaning for deno-2.6.6_1 build of www/deno | deno-2.6.6_1 ended at Fri Mar 13 03:43:50 CDT 2026 build time: 02:08:41 !!! build failure encountered !!!
The problem seems to be not with building gen/v8/snapshot.cc per se, but rather with the generation. How much RAM / parallelism are you giving the build?
Max RAM for it is set to 40G. That said the newest update to the to it seems to have fixed it.