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backend_x64/RegAlloc: Provide convenience function HostCall to save registers necessary as per host ABI

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This commit is contained in:
MerryMage 2016-07-11 15:28:10 +01:00
parent d92a771e3c
commit cbcf61a9e6
2 changed files with 38 additions and 1 deletions
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36
src/backend_x64/reg_alloc.cpp
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@ -133,6 +133,41 @@ Gen::X64Reg RegAlloc::ScratchRegister(std::initializer_list<HostLoc> desired_loc
return hostloc_to_x64.at(location);
}
void RegAlloc::HostCall(IR::Value* result_def, IR::Value* arg0_use, IR::Value* arg1_use, IR::Value* arg2_use, IR::Value* arg3_use) {
constexpr HostLoc AbiReturn = HostLoc::RAX;
#ifdef _WIN32
constexpr std::array<HostLoc, 4> AbiArgs = { HostLoc::RCX, HostLoc::RDX, HostLoc::R8, HostLoc::R9 };
/// Caller-saved registers other than AbiReturn or AbiArgs
constexpr std::array<HostLoc, 2> OtherCallerSave = { HostLoc::R10, HostLoc::R11 };
#else
constexpr std::array<HostLoc, 4> AbiArgs = { HostLoc::RDI, HostLoc::RSI, HostLoc::RDX, HostLoc::RCX };
/// Caller-saved registers other than AbiReturn or AbiArgs
constexpr std::array<HostLoc, 4> OtherCallerSave = { HostLoc::R8, HostLoc::R9, HostLoc::R10, HostLoc::R11 };
#endif
const std::array<IR::Value*, 4> args = {arg0_use, arg1_use, arg2_use, arg3_use};
// TODO: This works but almost certainly leads to suboptimal generated code.
for (HostLoc caller_save : OtherCallerSave) {
ScratchRegister({caller_save});
}
if (result_def) {
DefRegister(result_def, {AbiReturn});
} else {
ScratchRegister({AbiReturn});
}
for (size_t i = 0; i < AbiArgs.size(); i++) {
if (args[i]) {
UseRegister(args[i], {AbiArgs[i]});
} else {
ScratchRegister({AbiArgs[i]});
}
}
}
HostLoc RegAlloc::SelectARegister(std::initializer_list<HostLoc> desired_locations) const {
std::vector<HostLoc> candidates = desired_locations;
@ -207,6 +242,5 @@ void RegAlloc::Reset() {
remaining_uses.clear();
}
} // namespace BackendX64
} // namespace Dynarmic

3
src/backend_x64/reg_alloc.h
View file

@ -74,6 +74,9 @@ public:
/// Early-def, Late-use, single-use
Gen::X64Reg ScratchRegister(std::initializer_list<HostLoc> desired_locations = hostloc_any_register);
/// Late-def for result register, Early-use for all arguments, Each value is placed into registers according to host ABI.
void HostCall(IR::Value* result_def = nullptr, IR::Value* arg0_use = nullptr, IR::Value* arg1_use = nullptr, IR::Value* arg2_use = nullptr, IR::Value* arg3_use = nullptr);
// TODO: Values in host flags
void EndOfAllocScope();