dynarmic/src/backend/x64/emit_x64.cpp
MerryMage 55bddc767f backend/x64: Touch PEXT/PDEP code
* Use pext/pdep where not previously used
* Limit pext/pdep to non-AMD platforms due to slowness on AMD
* Use imul/and as alternatives for AMD and non-BMI2 platforms
2020-06-10 22:30:22 +01:00

337 lines
10 KiB
C++

/* This file is part of the dynarmic project.
* Copyright (c) 2016 MerryMage
* SPDX-License-Identifier: 0BSD
*/
#include <iterator>
#include <tsl/robin_set.h>
#include "backend/x64/block_of_code.h"
#include "backend/x64/emit_x64.h"
#include "backend/x64/nzcv_util.h"
#include "backend/x64/perf_map.h"
#include "common/assert.h"
#include "common/bit_util.h"
#include "common/common_types.h"
#include "common/scope_exit.h"
#include "common/variant_util.h"
#include "frontend/ir/basic_block.h"
#include "frontend/ir/microinstruction.h"
#include "frontend/ir/opcodes.h"
// TODO: Have ARM flags in host flags and not have them use up GPR registers unless necessary.
// TODO: Actually implement that proper instruction selector you've always wanted to sweetheart.
namespace Dynarmic::Backend::X64 {
using namespace Xbyak::util;
EmitContext::EmitContext(RegAlloc& reg_alloc, IR::Block& block)
: reg_alloc(reg_alloc), block(block) {}
size_t EmitContext::GetInstOffset(IR::Inst* inst) const {
return static_cast<size_t>(std::distance(block.begin(), IR::Block::iterator(inst)));
}
void EmitContext::EraseInstruction(IR::Inst* inst) {
block.Instructions().erase(inst);
inst->ClearArgs();
}
EmitX64::EmitX64(BlockOfCode& code) : code(code) {
exception_handler.Register(code);
}
EmitX64::~EmitX64() = default;
std::optional<EmitX64::BlockDescriptor> EmitX64::GetBasicBlock(IR::LocationDescriptor descriptor) const {
const auto iter = block_descriptors.find(descriptor);
if (iter == block_descriptors.end()) {
return std::nullopt;
}
return iter->second;
}
void EmitX64::EmitVoid(EmitContext&, IR::Inst*) {
}
void EmitX64::EmitBreakpoint(EmitContext&, IR::Inst*) {
code.int3();
}
void EmitX64::EmitIdentity(EmitContext& ctx, IR::Inst* inst) {
auto args = ctx.reg_alloc.GetArgumentInfo(inst);
if (!args[0].IsImmediate()) {
ctx.reg_alloc.DefineValue(inst, args[0]);
}
}
void EmitX64::PushRSBHelper(Xbyak::Reg64 loc_desc_reg, Xbyak::Reg64 index_reg, IR::LocationDescriptor target) {
using namespace Xbyak::util;
const auto iter = block_descriptors.find(target);
CodePtr target_code_ptr = iter != block_descriptors.end()
? iter->second.entrypoint
: code.GetReturnFromRunCodeAddress();
code.mov(index_reg.cvt32(), dword[r15 + code.GetJitStateInfo().offsetof_rsb_ptr]);
code.mov(loc_desc_reg, target.Value());
patch_information[target].mov_rcx.emplace_back(code.getCurr());
EmitPatchMovRcx(target_code_ptr);
code.mov(qword[r15 + index_reg * 8 + code.GetJitStateInfo().offsetof_rsb_location_descriptors], loc_desc_reg);
code.mov(qword[r15 + index_reg * 8 + code.GetJitStateInfo().offsetof_rsb_codeptrs], rcx);
code.add(index_reg.cvt32(), 1);
code.and_(index_reg.cvt32(), u32(code.GetJitStateInfo().rsb_ptr_mask));
code.mov(dword[r15 + code.GetJitStateInfo().offsetof_rsb_ptr], index_reg.cvt32());
}
void EmitX64::EmitPushRSB(EmitContext& ctx, IR::Inst* inst) {
auto args = ctx.reg_alloc.GetArgumentInfo(inst);
ASSERT(args[0].IsImmediate());
const u64 unique_hash_of_target = args[0].GetImmediateU64();
ctx.reg_alloc.ScratchGpr(HostLoc::RCX);
const Xbyak::Reg64 loc_desc_reg = ctx.reg_alloc.ScratchGpr();
const Xbyak::Reg64 index_reg = ctx.reg_alloc.ScratchGpr();
PushRSBHelper(loc_desc_reg, index_reg, IR::LocationDescriptor{unique_hash_of_target});
}
void EmitX64::EmitGetCarryFromOp(EmitContext&, IR::Inst*) {
ASSERT_MSG(false, "should never happen");
}
void EmitX64::EmitGetOverflowFromOp(EmitContext&, IR::Inst*) {
ASSERT_MSG(false, "should never happen");
}
void EmitX64::EmitGetGEFromOp(EmitContext&, IR::Inst*) {
ASSERT_MSG(false, "should never happen");
}
void EmitX64::EmitGetUpperFromOp(EmitContext&, IR::Inst*) {
ASSERT_MSG(false, "should never happen");
}
void EmitX64::EmitGetLowerFromOp(EmitContext&, IR::Inst*) {
ASSERT_MSG(false, "should never happen");
}
void EmitX64::EmitGetNZCVFromOp(EmitContext& ctx, IR::Inst* inst) {
auto args = ctx.reg_alloc.GetArgumentInfo(inst);
const int bitsize = [&]{
switch (args[0].GetType()) {
case IR::Type::U8:
return 8;
case IR::Type::U16:
return 16;
case IR::Type::U32:
return 32;
case IR::Type::U64:
return 64;
default:
UNREACHABLE();
}
}();
const Xbyak::Reg64 nzcv = ctx.reg_alloc.ScratchGpr(HostLoc::RAX);
const Xbyak::Reg value = ctx.reg_alloc.UseGpr(args[0]).changeBit(bitsize);
code.cmp(value, 0);
code.lahf();
code.seto(code.al);
ctx.reg_alloc.DefineValue(inst, nzcv);
}
void EmitX64::EmitNZCVFromPackedFlags(EmitContext& ctx, IR::Inst* inst) {
auto args = ctx.reg_alloc.GetArgumentInfo(inst);
if (args[0].IsImmediate()) {
const Xbyak::Reg32 nzcv = ctx.reg_alloc.ScratchGpr().cvt32();
u32 value = 0;
value |= Common::Bit<31>(args[0].GetImmediateU32()) ? (1 << 15) : 0;
value |= Common::Bit<30>(args[0].GetImmediateU32()) ? (1 << 14) : 0;
value |= Common::Bit<29>(args[0].GetImmediateU32()) ? (1 << 8) : 0;
value |= Common::Bit<28>(args[0].GetImmediateU32()) ? (1 << 0) : 0;
code.mov(nzcv, value);
ctx.reg_alloc.DefineValue(inst, nzcv);
} else if (code.HasFastBMI2()) {
const Xbyak::Reg32 nzcv = ctx.reg_alloc.UseScratchGpr(args[0]).cvt32();
const Xbyak::Reg32 tmp = ctx.reg_alloc.ScratchGpr().cvt32();
code.shr(nzcv, 28);
code.mov(tmp, NZCV::x64_mask);
code.pdep(nzcv, nzcv, tmp);
ctx.reg_alloc.DefineValue(inst, nzcv);
} else {
const Xbyak::Reg32 nzcv = ctx.reg_alloc.UseScratchGpr(args[0]).cvt32();
code.shr(nzcv, 28);
code.imul(nzcv, nzcv, NZCV::to_x64_multiplier);
code.and_(nzcv, NZCV::x64_mask);
ctx.reg_alloc.DefineValue(inst, nzcv);
}
}
void EmitX64::EmitAddCycles(size_t cycles) {
ASSERT(cycles < std::numeric_limits<u32>::max());
code.sub(qword[r15 + code.GetJitStateInfo().offsetof_cycles_remaining], static_cast<u32>(cycles));
}
Xbyak::Label EmitX64::EmitCond(IR::Cond cond) {
Xbyak::Label pass;
code.mov(eax, dword[r15 + code.GetJitStateInfo().offsetof_cpsr_nzcv]);
// sahf restores SF, ZF, CF
// add al, 0x7F restores OF
switch (cond) {
case IR::Cond::EQ: //z
code.sahf();
code.jz(pass);
break;
case IR::Cond::NE: //!z
code.sahf();
code.jnz(pass);
break;
case IR::Cond::CS: //c
code.sahf();
code.jc(pass);
break;
case IR::Cond::CC: //!c
code.sahf();
code.jnc(pass);
break;
case IR::Cond::MI: //n
code.sahf();
code.js(pass);
break;
case IR::Cond::PL: //!n
code.sahf();
code.jns(pass);
break;
case IR::Cond::VS: //v
code.add(al, 0x7F);
code.jo(pass);
break;
case IR::Cond::VC: //!v
code.add(al, 0x7F);
code.jno(pass);
break;
case IR::Cond::HI: //c & !z
code.sahf();
code.cmc();
code.ja(pass);
break;
case IR::Cond::LS: //!c | z
code.sahf();
code.cmc();
code.jna(pass);
break;
case IR::Cond::GE: // n == v
code.add(al, 0x7F);
code.sahf();
code.jge(pass);
break;
case IR::Cond::LT: // n != v
code.add(al, 0x7F);
code.sahf();
code.jl(pass);
break;
case IR::Cond::GT: // !z & (n == v)
code.add(al, 0x7F);
code.sahf();
code.jg(pass);
break;
case IR::Cond::LE: // z | (n != v)
code.add(al, 0x7F);
code.sahf();
code.jle(pass);
break;
default:
ASSERT_MSG(false, "Unknown cond {}", static_cast<size_t>(cond));
break;
}
return pass;
}
EmitX64::BlockDescriptor EmitX64::RegisterBlock(const IR::LocationDescriptor& descriptor, CodePtr entrypoint, size_t size) {
PerfMapRegister(entrypoint, code.getCurr(), LocationDescriptorToFriendlyName(descriptor));
Patch(descriptor, entrypoint);
BlockDescriptor block_desc{entrypoint, size};
block_descriptors.emplace(descriptor.Value(), block_desc);
return block_desc;
}
void EmitX64::EmitTerminal(IR::Terminal terminal, IR::LocationDescriptor initial_location, bool is_single_step) {
Common::VisitVariant<void>(terminal, [this, initial_location, is_single_step](auto x) {
using T = std::decay_t<decltype(x)>;
if constexpr (!std::is_same_v<T, IR::Term::Invalid>) {
this->EmitTerminalImpl(x, initial_location, is_single_step);
} else {
ASSERT_MSG(false, "Invalid terminal");
}
});
}
void EmitX64::Patch(const IR::LocationDescriptor& target_desc, CodePtr target_code_ptr) {
const CodePtr save_code_ptr = code.getCurr();
const PatchInformation& patch_info = patch_information[target_desc];
for (CodePtr location : patch_info.jg) {
code.SetCodePtr(location);
EmitPatchJg(target_desc, target_code_ptr);
}
for (CodePtr location : patch_info.jmp) {
code.SetCodePtr(location);
EmitPatchJmp(target_desc, target_code_ptr);
}
for (CodePtr location : patch_info.mov_rcx) {
code.SetCodePtr(location);
EmitPatchMovRcx(target_code_ptr);
}
code.SetCodePtr(save_code_ptr);
}
void EmitX64::Unpatch(const IR::LocationDescriptor& target_desc) {
Patch(target_desc, nullptr);
}
void EmitX64::ClearCache() {
block_descriptors.clear();
patch_information.clear();
PerfMapClear();
}
void EmitX64::InvalidateBasicBlocks(const tsl::robin_set<IR::LocationDescriptor>& locations) {
code.EnableWriting();
SCOPE_EXIT { code.DisableWriting(); };
for (const auto &descriptor : locations) {
const auto it = block_descriptors.find(descriptor);
if (it == block_descriptors.end()) {
continue;
}
if (patch_information.count(descriptor)) {
Unpatch(descriptor);
}
block_descriptors.erase(it);
}
}
} // namespace Dynarmic::Backend::X64