[ASDAlexander77]

A @cpp class can now call C++ virtual methods that take a trivially copyable struct by value, or return a small one in registers. tsbindgen binds such methods instead of skipping them.

tslang

LowerToLLVM (lowerCppCallArgs, on both call and invoke): a tuple argument of a @cpp call is copied into a zeroed slot and passed the way the target passes the record. TargetInfo::cppRecordAbi selects the rules:

ABI	Up to 16 bytes	Larger
MSVC x64	1, 2, 4 or 8 bytes: in a register, as an integer of that size; any other size: a pointer to the copy	a pointer to the copy
SysV x86-64	integers and pointers: one or two 64-bit registers, if that many of the six remain (counted), else on the stack	on the stack (byval)
AAPCS64	[N x i64], which the backend places all in registers or all on the stack	a pointer to the copy

A tuple the Itanium ABI returns in registers is read back from i64 / { i64, i64 } / [2 x i64]. That now covers any trivial record of up to 16 bytes of integers and pointers, not only one or two 8-byte fields.

These are errors rather than wrong calls:

• floating-point records under the Itanium ABI (SSE registers, HFAs);
• an unmarked trivial record of more than 16 bytes returned (mark it @cppnontrivial);
• records by value in non-virtual methods or in methods with a body.

tsbindgen

• A virtual method's by-value record parameter is emitted as the record's own type, unless the record:
  • isn't trivially copyable (MSVC would destroy, say, a RefCountPtr in the callee and release a reference the caller never added),
  • is a union,
  • or has floating-point fields under the Itanium ABI.
• Under the Itanium ABI, a record result of more than 16 bytes is @cppnontrivial.

docs/cpp-classes.md ("Structs passed by value") and the README document this, including the cases left out.

Tests

• abi_host.cpp gains byValue (records of 4, 8, 12, 16 and 24 bytes, then an int), pair, flags (three bools) and r12 (12 bytes). It runs against MSVC in test-jit-cppvtable-abi and against g++/clang on Linux CI. The callee changes its by-value copies, and the test checks that the caller's tuples are unchanged.
• test-compile-cppvtable-records-{msvc,x86_64,aarch64} check each ABI's call shape in the IR on any host.
• itanium_float_param.ts and itanium_record.ts (now floats) cover the errors.
• TsClangImporterTests gain RecordsPassedByValue and RecordsReturnedInMemoryOrFloatRegisters.
• Local results: full suite 4085/4085 on Windows, plus the new tests.
• Itanium x86-64 against g++ (WSL): all six checks pass. The same check compiled with pre-alpha101 silently got both by-value cases wrong.

Downstream

native_ts_graphics' tools/gen_nvrhi_classes.py hand-wrote 11 NVRHI methods per ABI because tsbindgen skipped them. With this change tsbindgen binds them all. A local build against this tslang passes nvrhi_direct and headless on D3D12 and Vulkan (-debug) and on Android x86_64 and arm64. That cleanup lands after a release.

🤖 Generated with Claude Code