1 //===-- AArch64TargetMachine.cpp - Define TargetMachine for AArch64 -------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
11 //===----------------------------------------------------------------------===//
14 #include "AArch64CallLowering.h"
15 #include "AArch64InstructionSelector.h"
16 #include "AArch64LegalizerInfo.h"
17 #include "AArch64RegisterBankInfo.h"
18 #include "AArch64TargetMachine.h"
19 #include "AArch64TargetObjectFile.h"
20 #include "AArch64TargetTransformInfo.h"
21 #include "llvm/CodeGen/GlobalISel/IRTranslator.h"
22 #include "llvm/CodeGen/GlobalISel/InstructionSelect.h"
23 #include "llvm/CodeGen/GlobalISel/Legalizer.h"
24 #include "llvm/CodeGen/GlobalISel/RegBankSelect.h"
25 #include "llvm/CodeGen/MachineScheduler.h"
26 #include "llvm/CodeGen/Passes.h"
27 #include "llvm/CodeGen/RegAllocRegistry.h"
28 #include "llvm/CodeGen/TargetPassConfig.h"
29 #include "llvm/IR/Function.h"
30 #include "llvm/IR/LegacyPassManager.h"
31 #include "llvm/InitializePasses.h"
32 #include "llvm/Support/CommandLine.h"
33 #include "llvm/Support/TargetRegistry.h"
34 #include "llvm/Target/TargetOptions.h"
35 #include "llvm/Transforms/Scalar.h"
38 static cl::opt<bool> EnableCCMP("aarch64-enable-ccmp",
39 cl::desc("Enable the CCMP formation pass"),
40 cl::init(true), cl::Hidden);
42 static cl::opt<bool> EnableMCR("aarch64-enable-mcr",
43 cl::desc("Enable the machine combiner pass"),
44 cl::init(true), cl::Hidden);
46 static cl::opt<bool> EnableStPairSuppress("aarch64-enable-stp-suppress",
47 cl::desc("Suppress STP for AArch64"),
48 cl::init(true), cl::Hidden);
50 static cl::opt<bool> EnableAdvSIMDScalar(
51 "aarch64-enable-simd-scalar",
52 cl::desc("Enable use of AdvSIMD scalar integer instructions"),
53 cl::init(false), cl::Hidden);
56 EnablePromoteConstant("aarch64-enable-promote-const",
57 cl::desc("Enable the promote constant pass"),
58 cl::init(true), cl::Hidden);
60 static cl::opt<bool> EnableCollectLOH(
61 "aarch64-enable-collect-loh",
62 cl::desc("Enable the pass that emits the linker optimization hints (LOH)"),
63 cl::init(true), cl::Hidden);
66 EnableDeadRegisterElimination("aarch64-enable-dead-defs", cl::Hidden,
67 cl::desc("Enable the pass that removes dead"
68 " definitons and replaces stores to"
69 " them with stores to the zero"
73 static cl::opt<bool> EnableRedundantCopyElimination(
74 "aarch64-enable-copyelim",
75 cl::desc("Enable the redundant copy elimination pass"), cl::init(true),
78 static cl::opt<bool> EnableLoadStoreOpt("aarch64-enable-ldst-opt",
79 cl::desc("Enable the load/store pair"
80 " optimization pass"),
81 cl::init(true), cl::Hidden);
83 static cl::opt<bool> EnableAtomicTidy(
84 "aarch64-enable-atomic-cfg-tidy", cl::Hidden,
85 cl::desc("Run SimplifyCFG after expanding atomic operations"
86 " to make use of cmpxchg flow-based information"),
90 EnableEarlyIfConversion("aarch64-enable-early-ifcvt", cl::Hidden,
91 cl::desc("Run early if-conversion"),
95 EnableCondOpt("aarch64-enable-condopt",
96 cl::desc("Enable the condition optimizer pass"),
97 cl::init(true), cl::Hidden);
100 EnableA53Fix835769("aarch64-fix-cortex-a53-835769", cl::Hidden,
101 cl::desc("Work around Cortex-A53 erratum 835769"),
105 EnableAddressTypePromotion("aarch64-enable-type-promotion", cl::Hidden,
106 cl::desc("Enable the type promotion pass"),
110 EnableGEPOpt("aarch64-enable-gep-opt", cl::Hidden,
111 cl::desc("Enable optimizations on complex GEPs"),
115 BranchRelaxation("aarch64-enable-branch-relax", cl::Hidden, cl::init(true),
116 cl::desc("Relax out of range conditional branches"));
118 // FIXME: Unify control over GlobalMerge.
119 static cl::opt<cl::boolOrDefault>
120 EnableGlobalMerge("aarch64-enable-global-merge", cl::Hidden,
121 cl::desc("Enable the global merge pass"));
124 EnableLoopDataPrefetch("aarch64-enable-loop-data-prefetch", cl::Hidden,
125 cl::desc("Enable the loop data prefetch pass"),
128 extern "C" void LLVMInitializeAArch64Target() {
129 // Register the target.
130 RegisterTargetMachine<AArch64leTargetMachine> X(getTheAArch64leTarget());
131 RegisterTargetMachine<AArch64beTargetMachine> Y(getTheAArch64beTarget());
132 RegisterTargetMachine<AArch64leTargetMachine> Z(getTheARM64Target());
133 auto PR = PassRegistry::getPassRegistry();
134 initializeGlobalISel(*PR);
135 initializeAArch64A53Fix835769Pass(*PR);
136 initializeAArch64A57FPLoadBalancingPass(*PR);
137 initializeAArch64AddressTypePromotionPass(*PR);
138 initializeAArch64AdvSIMDScalarPass(*PR);
139 initializeAArch64CollectLOHPass(*PR);
140 initializeAArch64ConditionalComparesPass(*PR);
141 initializeAArch64ConditionOptimizerPass(*PR);
142 initializeAArch64DeadRegisterDefinitionsPass(*PR);
143 initializeAArch64ExpandPseudoPass(*PR);
144 initializeAArch64LoadStoreOptPass(*PR);
145 initializeAArch64VectorByElementOptPass(*PR);
146 initializeAArch64PromoteConstantPass(*PR);
147 initializeAArch64RedundantCopyEliminationPass(*PR);
148 initializeAArch64StorePairSuppressPass(*PR);
149 initializeLDTLSCleanupPass(*PR);
152 //===----------------------------------------------------------------------===//
153 // AArch64 Lowering public interface.
154 //===----------------------------------------------------------------------===//
155 static std::unique_ptr<TargetLoweringObjectFile> createTLOF(const Triple &TT) {
156 if (TT.isOSBinFormatMachO())
157 return make_unique<AArch64_MachoTargetObjectFile>();
159 return make_unique<AArch64_ELFTargetObjectFile>();
162 // Helper function to build a DataLayout string
163 static std::string computeDataLayout(const Triple &TT,
164 const MCTargetOptions &Options,
166 if (Options.getABIName() == "ilp32")
167 return "e-m:e-p:32:32-i8:8-i16:16-i64:64-S128";
168 if (TT.isOSBinFormatMachO())
169 return "e-m:o-i64:64-i128:128-n32:64-S128";
171 return "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128";
172 return "E-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128";
175 static Reloc::Model getEffectiveRelocModel(const Triple &TT,
176 Optional<Reloc::Model> RM) {
177 // AArch64 Darwin is always PIC.
180 // On ELF platforms the default static relocation model has a smart enough
181 // linker to cope with referencing external symbols defined in a shared
182 // library. Hence DynamicNoPIC doesn't need to be promoted to PIC.
183 if (!RM.hasValue() || *RM == Reloc::DynamicNoPIC)
184 return Reloc::Static;
188 /// Create an AArch64 architecture model.
190 AArch64TargetMachine::AArch64TargetMachine(
191 const Target &T, const Triple &TT, StringRef CPU, StringRef FS,
192 const TargetOptions &Options, Optional<Reloc::Model> RM,
193 CodeModel::Model CM, CodeGenOpt::Level OL, bool LittleEndian)
194 // This nested ternary is horrible, but DL needs to be properly
195 // initialized before TLInfo is constructed.
196 : LLVMTargetMachine(T, computeDataLayout(TT, Options.MCOptions,
198 TT, CPU, FS, Options,
199 getEffectiveRelocModel(TT, RM), CM, OL),
200 TLOF(createTLOF(getTargetTriple())),
201 isLittle(LittleEndian) {
205 AArch64TargetMachine::~AArch64TargetMachine() {}
207 #ifdef LLVM_BUILD_GLOBAL_ISEL
209 struct AArch64GISelActualAccessor : public GISelAccessor {
210 std::unique_ptr<CallLowering> CallLoweringInfo;
211 std::unique_ptr<InstructionSelector> InstSelector;
212 std::unique_ptr<LegalizerInfo> Legalizer;
213 std::unique_ptr<RegisterBankInfo> RegBankInfo;
214 const CallLowering *getCallLowering() const override {
215 return CallLoweringInfo.get();
217 const InstructionSelector *getInstructionSelector() const override {
218 return InstSelector.get();
220 const LegalizerInfo *getLegalizerInfo() const override {
221 return Legalizer.get();
223 const RegisterBankInfo *getRegBankInfo() const override {
224 return RegBankInfo.get();
227 } // End anonymous namespace.
230 const AArch64Subtarget *
231 AArch64TargetMachine::getSubtargetImpl(const Function &F) const {
232 Attribute CPUAttr = F.getFnAttribute("target-cpu");
233 Attribute FSAttr = F.getFnAttribute("target-features");
235 std::string CPU = !CPUAttr.hasAttribute(Attribute::None)
236 ? CPUAttr.getValueAsString().str()
238 std::string FS = !FSAttr.hasAttribute(Attribute::None)
239 ? FSAttr.getValueAsString().str()
242 auto &I = SubtargetMap[CPU + FS];
244 // This needs to be done before we create a new subtarget since any
245 // creation will depend on the TM and the code generation flags on the
246 // function that reside in TargetOptions.
247 resetTargetOptions(F);
248 I = llvm::make_unique<AArch64Subtarget>(TargetTriple, CPU, FS, *this,
250 #ifndef LLVM_BUILD_GLOBAL_ISEL
251 GISelAccessor *GISel = new GISelAccessor();
253 AArch64GISelActualAccessor *GISel =
254 new AArch64GISelActualAccessor();
255 GISel->CallLoweringInfo.reset(
256 new AArch64CallLowering(*I->getTargetLowering()));
257 GISel->Legalizer.reset(new AArch64LegalizerInfo());
259 auto *RBI = new AArch64RegisterBankInfo(*I->getRegisterInfo());
261 // FIXME: At this point, we can't rely on Subtarget having RBI.
262 // It's awkward to mix passing RBI and the Subtarget; should we pass
264 GISel->InstSelector.reset(new AArch64InstructionSelector(*this, *I, *RBI));
266 GISel->RegBankInfo.reset(RBI);
268 I->setGISelAccessor(*GISel);
273 void AArch64leTargetMachine::anchor() { }
275 AArch64leTargetMachine::AArch64leTargetMachine(
276 const Target &T, const Triple &TT, StringRef CPU, StringRef FS,
277 const TargetOptions &Options, Optional<Reloc::Model> RM,
278 CodeModel::Model CM, CodeGenOpt::Level OL)
279 : AArch64TargetMachine(T, TT, CPU, FS, Options, RM, CM, OL, true) {}
281 void AArch64beTargetMachine::anchor() { }
283 AArch64beTargetMachine::AArch64beTargetMachine(
284 const Target &T, const Triple &TT, StringRef CPU, StringRef FS,
285 const TargetOptions &Options, Optional<Reloc::Model> RM,
286 CodeModel::Model CM, CodeGenOpt::Level OL)
287 : AArch64TargetMachine(T, TT, CPU, FS, Options, RM, CM, OL, false) {}
290 /// AArch64 Code Generator Pass Configuration Options.
291 class AArch64PassConfig : public TargetPassConfig {
293 AArch64PassConfig(AArch64TargetMachine *TM, PassManagerBase &PM)
294 : TargetPassConfig(TM, PM) {
295 if (TM->getOptLevel() != CodeGenOpt::None)
296 substitutePass(&PostRASchedulerID, &PostMachineSchedulerID);
299 AArch64TargetMachine &getAArch64TargetMachine() const {
300 return getTM<AArch64TargetMachine>();
304 createMachineScheduler(MachineSchedContext *C) const override {
305 ScheduleDAGMILive *DAG = createGenericSchedLive(C);
306 DAG->addMutation(createLoadClusterDAGMutation(DAG->TII, DAG->TRI));
307 DAG->addMutation(createStoreClusterDAGMutation(DAG->TII, DAG->TRI));
308 DAG->addMutation(createMacroFusionDAGMutation(DAG->TII));
312 void addIRPasses() override;
313 bool addPreISel() override;
314 bool addInstSelector() override;
315 #ifdef LLVM_BUILD_GLOBAL_ISEL
316 bool addIRTranslator() override;
317 bool addLegalizeMachineIR() override;
318 bool addRegBankSelect() override;
319 bool addGlobalInstructionSelect() override;
321 bool addILPOpts() override;
322 void addPreRegAlloc() override;
323 void addPostRegAlloc() override;
324 void addPreSched2() override;
325 void addPreEmitPass() override;
329 TargetIRAnalysis AArch64TargetMachine::getTargetIRAnalysis() {
330 return TargetIRAnalysis([this](const Function &F) {
331 return TargetTransformInfo(AArch64TTIImpl(this, F));
335 TargetPassConfig *AArch64TargetMachine::createPassConfig(PassManagerBase &PM) {
336 return new AArch64PassConfig(this, PM);
339 void AArch64PassConfig::addIRPasses() {
340 // Always expand atomic operations, we don't deal with atomicrmw or cmpxchg
342 addPass(createAtomicExpandPass(TM));
344 // Cmpxchg instructions are often used with a subsequent comparison to
345 // determine whether it succeeded. We can exploit existing control-flow in
346 // ldrex/strex loops to simplify this, but it needs tidying up.
347 if (TM->getOptLevel() != CodeGenOpt::None && EnableAtomicTidy)
348 addPass(createCFGSimplificationPass());
350 // Run LoopDataPrefetch
352 // Run this before LSR to remove the multiplies involved in computing the
353 // pointer values N iterations ahead.
354 if (TM->getOptLevel() != CodeGenOpt::None && EnableLoopDataPrefetch)
355 addPass(createLoopDataPrefetchPass());
357 TargetPassConfig::addIRPasses();
359 // Match interleaved memory accesses to ldN/stN intrinsics.
360 if (TM->getOptLevel() != CodeGenOpt::None)
361 addPass(createInterleavedAccessPass(TM));
363 if (TM->getOptLevel() == CodeGenOpt::Aggressive && EnableGEPOpt) {
364 // Call SeparateConstOffsetFromGEP pass to extract constants within indices
365 // and lower a GEP with multiple indices to either arithmetic operations or
366 // multiple GEPs with single index.
367 addPass(createSeparateConstOffsetFromGEPPass(TM, true));
368 // Call EarlyCSE pass to find and remove subexpressions in the lowered
370 addPass(createEarlyCSEPass());
371 // Do loop invariant code motion in case part of the lowered result is
373 addPass(createLICMPass());
377 // Pass Pipeline Configuration
378 bool AArch64PassConfig::addPreISel() {
379 // Run promote constant before global merge, so that the promoted constants
380 // get a chance to be merged
381 if (TM->getOptLevel() != CodeGenOpt::None && EnablePromoteConstant)
382 addPass(createAArch64PromoteConstantPass());
383 // FIXME: On AArch64, this depends on the type.
384 // Basically, the addressable offsets are up to 4095 * Ty.getSizeInBytes().
385 // and the offset has to be a multiple of the related size in bytes.
386 if ((TM->getOptLevel() != CodeGenOpt::None &&
387 EnableGlobalMerge == cl::BOU_UNSET) ||
388 EnableGlobalMerge == cl::BOU_TRUE) {
389 bool OnlyOptimizeForSize = (TM->getOptLevel() < CodeGenOpt::Aggressive) &&
390 (EnableGlobalMerge == cl::BOU_UNSET);
391 addPass(createGlobalMergePass(TM, 4095, OnlyOptimizeForSize));
394 if (TM->getOptLevel() != CodeGenOpt::None && EnableAddressTypePromotion)
395 addPass(createAArch64AddressTypePromotionPass());
400 bool AArch64PassConfig::addInstSelector() {
401 addPass(createAArch64ISelDag(getAArch64TargetMachine(), getOptLevel()));
403 // For ELF, cleanup any local-dynamic TLS accesses (i.e. combine as many
404 // references to _TLS_MODULE_BASE_ as possible.
405 if (TM->getTargetTriple().isOSBinFormatELF() &&
406 getOptLevel() != CodeGenOpt::None)
407 addPass(createAArch64CleanupLocalDynamicTLSPass());
412 #ifdef LLVM_BUILD_GLOBAL_ISEL
413 bool AArch64PassConfig::addIRTranslator() {
414 addPass(new IRTranslator());
417 bool AArch64PassConfig::addLegalizeMachineIR() {
418 addPass(new Legalizer());
421 bool AArch64PassConfig::addRegBankSelect() {
422 addPass(new RegBankSelect());
425 bool AArch64PassConfig::addGlobalInstructionSelect() {
426 addPass(new InstructionSelect());
431 bool AArch64PassConfig::addILPOpts() {
433 addPass(createAArch64ConditionOptimizerPass());
435 addPass(createAArch64ConditionalCompares());
437 addPass(&MachineCombinerID);
438 if (EnableEarlyIfConversion)
439 addPass(&EarlyIfConverterID);
440 if (EnableStPairSuppress)
441 addPass(createAArch64StorePairSuppressPass());
442 addPass(createAArch64VectorByElementOptPass());
446 void AArch64PassConfig::addPreRegAlloc() {
447 // Change dead register definitions to refer to the zero register.
448 if (TM->getOptLevel() != CodeGenOpt::None && EnableDeadRegisterElimination)
449 addPass(createAArch64DeadRegisterDefinitions());
451 // Use AdvSIMD scalar instructions whenever profitable.
452 if (TM->getOptLevel() != CodeGenOpt::None && EnableAdvSIMDScalar) {
453 addPass(createAArch64AdvSIMDScalar());
454 // The AdvSIMD pass may produce copies that can be rewritten to
455 // be register coaleascer friendly.
456 addPass(&PeepholeOptimizerID);
460 void AArch64PassConfig::addPostRegAlloc() {
461 // Remove redundant copy instructions.
462 if (TM->getOptLevel() != CodeGenOpt::None && EnableRedundantCopyElimination)
463 addPass(createAArch64RedundantCopyEliminationPass());
465 if (TM->getOptLevel() != CodeGenOpt::None && usingDefaultRegAlloc())
466 // Improve performance for some FP/SIMD code for A57.
467 addPass(createAArch64A57FPLoadBalancing());
470 void AArch64PassConfig::addPreSched2() {
471 // Expand some pseudo instructions to allow proper scheduling.
472 addPass(createAArch64ExpandPseudoPass());
473 // Use load/store pair instructions when possible.
474 if (TM->getOptLevel() != CodeGenOpt::None && EnableLoadStoreOpt)
475 addPass(createAArch64LoadStoreOptimizationPass());
478 void AArch64PassConfig::addPreEmitPass() {
479 if (EnableA53Fix835769)
480 addPass(createAArch64A53Fix835769());
481 // Relax conditional branch instructions if they're otherwise out of
482 // range of their destination.
483 if (BranchRelaxation)
484 addPass(&BranchRelaxationPassID);
486 if (TM->getOptLevel() != CodeGenOpt::None && EnableCollectLOH &&
487 TM->getTargetTriple().isOSBinFormatMachO())
488 addPass(createAArch64CollectLOHPass());