TCA emitCall(vixl::MacroAssembler& a, CppCall call) {
switch (call.kind()) {
case CppCall::Kind::Direct:
a. Mov (rHostCallReg, reinterpret_cast<intptr_t>(call.address()));
break;
case CppCall::Kind::Virtual:
a. Ldr (rHostCallReg, argReg(0)[0]);
a. Ldr (rHostCallReg, rHostCallReg[call.vtableOffset()]);
break;
case CppCall::Kind::IndirectReg:
case CppCall::Kind::IndirectVreg:
// call indirect currently not implemented. It'll be something like
// a.Br(x2a(call.getReg()))
not_implemented();
always_assert(0);
break;
case CppCall::Kind::ArrayVirt:
case CppCall::Kind::Destructor:
not_implemented();
always_assert(0);
break;
}
using namespace vixl;
auto fixupAddr = a.frontier();
a. HostCall(6);
// Note that the fixup address for a HostCall is directly *before* the
// HostCall, not after as in the native case. This is because, in simulation
// mode we look at the simulator's PC at the time the fixup is invoked, and it
// will still be pointing to the HostCall; it's not advanced past it until the
// host call returns. In the native case, by contrast, we'll be looking at
// return addresses, which point after the call.
return fixupAddr;
}
Vpoint emitCall(Vout& v, CppCall call, RegSet args) {
PhysReg arg0(argReg(0));
PhysReg rHostCall(rHostCallReg);
switch (call.kind()) {
case CppCall::Kind::Direct:
v << ldimm{reinterpret_cast<intptr_t>(call.address()), rHostCall};
break;
case CppCall::Kind::Virtual:
v << loadq{arg0[0], rHostCall};
v << loadq{rHostCall[call.vtableOffset()], rHostCall};
break;
case CppCall::Kind::IndirectReg:
case CppCall::Kind::IndirectVreg:
// call indirect currently not implemented. It'll be something like
// a.Br(x2a(call.getReg()))
not_implemented();
always_assert(0);
break;
case CppCall::Kind::ArrayVirt:
case CppCall::Kind::Destructor:
not_implemented();
always_assert(0);
break;
}
uint8_t argc = args.size();
args.add(rHostCall);
auto fixupAddr = v.makePoint();
v << hostcall{args, argc, fixupAddr};
return fixupAddr;
}
void emitCall(Vout& v, CppCall target, RegSet args) {
switch (target.kind()) {
case CppCall::Kind::Direct:
v << call{static_cast<TCA>(target.address()), args};
return;
case CppCall::Kind::Virtual:
// Virtual call. Load method's address from proper offset off of object in
// rdi, using rax as scratch.
v << load{*reg::rdi, reg::rax};
v << callm{reg::rax[target.vtableOffset()], args};
return;
case CppCall::Kind::ArrayVirt: {
auto const addr = reinterpret_cast<intptr_t>(target.arrayTable());
v << loadzbl{reg::rdi[HeaderKindOffset], reg::eax};
if (deltaFits(addr, sz::dword)) {
v << callm{baseless(reg::rax * 8 + addr), args};
} else {
auto const base = v.makeReg();
v << ldimmq{addr, base};
v << callm{base[reg::rax * 8], args};
}
static_assert(sizeof(HeaderKind) == 1, "");
return;
}
case CppCall::Kind::Destructor:
// this movzbq is only needed because callers aren't required to
// zero-extend the type.
auto zextType = v.makeReg();
v << movzbq{target.reg(), zextType};
auto dtor_ptr = lookupDestructor(v, zextType);
v << callm{dtor_ptr, args};
return;
}
not_reached();
}