xref: /llvm-project/llvm/lib/Target/X86/X86TargetMachine.cpp (revision bf6e39367cb27e7fc77a574c9748c5ff16a68d83)
1 //===-- X86TargetMachine.cpp - Define TargetMachine for the X86 -----------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines the X86 specific subclass of TargetMachine.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "X86TargetMachine.h"
14 #include "MCTargetDesc/X86MCTargetDesc.h"
15 #include "TargetInfo/X86TargetInfo.h"
16 #include "X86.h"
17 #include "X86MachineFunctionInfo.h"
18 #include "X86MacroFusion.h"
19 #include "X86Subtarget.h"
20 #include "X86TargetObjectFile.h"
21 #include "X86TargetTransformInfo.h"
22 #include "llvm/ADT/STLExtras.h"
23 #include "llvm/ADT/SmallString.h"
24 #include "llvm/ADT/StringRef.h"
25 #include "llvm/Analysis/TargetTransformInfo.h"
26 #include "llvm/CodeGen/ExecutionDomainFix.h"
27 #include "llvm/CodeGen/GlobalISel/CSEInfo.h"
28 #include "llvm/CodeGen/GlobalISel/CallLowering.h"
29 #include "llvm/CodeGen/GlobalISel/IRTranslator.h"
30 #include "llvm/CodeGen/GlobalISel/InstructionSelect.h"
31 #include "llvm/CodeGen/GlobalISel/InstructionSelector.h"
32 #include "llvm/CodeGen/GlobalISel/Legalizer.h"
33 #include "llvm/CodeGen/GlobalISel/RegBankSelect.h"
34 #include "llvm/CodeGen/MachineScheduler.h"
35 #include "llvm/CodeGen/Passes.h"
36 #include "llvm/CodeGen/RegAllocRegistry.h"
37 #include "llvm/CodeGen/TargetPassConfig.h"
38 #include "llvm/IR/Attributes.h"
39 #include "llvm/IR/DataLayout.h"
40 #include "llvm/IR/Function.h"
41 #include "llvm/MC/MCAsmInfo.h"
42 #include "llvm/MC/TargetRegistry.h"
43 #include "llvm/Pass.h"
44 #include "llvm/Support/CodeGen.h"
45 #include "llvm/Support/CommandLine.h"
46 #include "llvm/Support/ErrorHandling.h"
47 #include "llvm/Target/TargetLoweringObjectFile.h"
48 #include "llvm/Target/TargetOptions.h"
49 #include "llvm/TargetParser/Triple.h"
50 #include "llvm/Transforms/CFGuard.h"
51 #include <memory>
52 #include <optional>
53 #include <string>
54 
55 using namespace llvm;
56 
57 static cl::opt<bool> EnableMachineCombinerPass("x86-machine-combiner",
58                                cl::desc("Enable the machine combiner pass"),
59                                cl::init(true), cl::Hidden);
60 
61 static cl::opt<bool>
62     EnableTileRAPass("x86-tile-ra",
63                      cl::desc("Enable the tile register allocation pass"),
64                      cl::init(true), cl::Hidden);
65 
66 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeX86Target() {
67   // Register the target.
68   RegisterTargetMachine<X86TargetMachine> X(getTheX86_32Target());
69   RegisterTargetMachine<X86TargetMachine> Y(getTheX86_64Target());
70 
71   PassRegistry &PR = *PassRegistry::getPassRegistry();
72   initializeX86LowerAMXIntrinsicsLegacyPassPass(PR);
73   initializeX86LowerAMXTypeLegacyPassPass(PR);
74   initializeX86PreAMXConfigPassPass(PR);
75   initializeX86PreTileConfigPass(PR);
76   initializeGlobalISel(PR);
77   initializeWinEHStatePassPass(PR);
78   initializeFixupBWInstPassPass(PR);
79   initializeEvexToVexInstPassPass(PR);
80   initializeFixupLEAPassPass(PR);
81   initializeFPSPass(PR);
82   initializeX86FixupSetCCPassPass(PR);
83   initializeX86CallFrameOptimizationPass(PR);
84   initializeX86CmovConverterPassPass(PR);
85   initializeX86TileConfigPass(PR);
86   initializeX86FastPreTileConfigPass(PR);
87   initializeX86FastTileConfigPass(PR);
88   initializeKCFIPass(PR);
89   initializeX86LowerTileCopyPass(PR);
90   initializeX86ExpandPseudoPass(PR);
91   initializeX86ExecutionDomainFixPass(PR);
92   initializeX86DomainReassignmentPass(PR);
93   initializeX86AvoidSFBPassPass(PR);
94   initializeX86AvoidTrailingCallPassPass(PR);
95   initializeX86SpeculativeLoadHardeningPassPass(PR);
96   initializeX86SpeculativeExecutionSideEffectSuppressionPass(PR);
97   initializeX86FlagsCopyLoweringPassPass(PR);
98   initializeX86LoadValueInjectionLoadHardeningPassPass(PR);
99   initializeX86LoadValueInjectionRetHardeningPassPass(PR);
100   initializeX86OptimizeLEAPassPass(PR);
101   initializeX86PartialReductionPass(PR);
102   initializePseudoProbeInserterPass(PR);
103   initializeX86ReturnThunksPass(PR);
104   initializeX86DAGToDAGISelPass(PR);
105   initializeX86ArgumentStackSlotPassPass(PR);
106 }
107 
108 static std::unique_ptr<TargetLoweringObjectFile> createTLOF(const Triple &TT) {
109   if (TT.isOSBinFormatMachO()) {
110     if (TT.getArch() == Triple::x86_64)
111       return std::make_unique<X86_64MachoTargetObjectFile>();
112     return std::make_unique<TargetLoweringObjectFileMachO>();
113   }
114 
115   if (TT.isOSBinFormatCOFF())
116     return std::make_unique<TargetLoweringObjectFileCOFF>();
117   return std::make_unique<X86ELFTargetObjectFile>();
118 }
119 
120 static std::string computeDataLayout(const Triple &TT) {
121   // X86 is little endian
122   std::string Ret = "e";
123 
124   Ret += DataLayout::getManglingComponent(TT);
125   // X86 and x32 have 32 bit pointers.
126   if (!TT.isArch64Bit() || TT.isX32() || TT.isOSNaCl())
127     Ret += "-p:32:32";
128 
129   // Address spaces for 32 bit signed, 32 bit unsigned, and 64 bit pointers.
130   Ret += "-p270:32:32-p271:32:32-p272:64:64";
131 
132   // Some ABIs align 64 bit integers and doubles to 64 bits, others to 32.
133   if (TT.isArch64Bit() || TT.isOSWindows() || TT.isOSNaCl())
134     Ret += "-i64:64";
135   else if (TT.isOSIAMCU())
136     Ret += "-i64:32-f64:32";
137   else
138     Ret += "-f64:32:64";
139 
140   // Some ABIs align long double to 128 bits, others to 32.
141   if (TT.isOSNaCl() || TT.isOSIAMCU())
142     ; // No f80
143   else if (TT.isArch64Bit() || TT.isOSDarwin() || TT.isWindowsMSVCEnvironment())
144     Ret += "-f80:128";
145   else
146     Ret += "-f80:32";
147 
148   if (TT.isOSIAMCU())
149     Ret += "-f128:32";
150 
151   // The registers can hold 8, 16, 32 or, in x86-64, 64 bits.
152   if (TT.isArch64Bit())
153     Ret += "-n8:16:32:64";
154   else
155     Ret += "-n8:16:32";
156 
157   // The stack is aligned to 32 bits on some ABIs and 128 bits on others.
158   if ((!TT.isArch64Bit() && TT.isOSWindows()) || TT.isOSIAMCU())
159     Ret += "-a:0:32-S32";
160   else
161     Ret += "-S128";
162 
163   return Ret;
164 }
165 
166 static Reloc::Model getEffectiveRelocModel(const Triple &TT, bool JIT,
167                                            std::optional<Reloc::Model> RM) {
168   bool is64Bit = TT.getArch() == Triple::x86_64;
169   if (!RM) {
170     // JIT codegen should use static relocations by default, since it's
171     // typically executed in process and not relocatable.
172     if (JIT)
173       return Reloc::Static;
174 
175     // Darwin defaults to PIC in 64 bit mode and dynamic-no-pic in 32 bit mode.
176     // Win64 requires rip-rel addressing, thus we force it to PIC. Otherwise we
177     // use static relocation model by default.
178     if (TT.isOSDarwin()) {
179       if (is64Bit)
180         return Reloc::PIC_;
181       return Reloc::DynamicNoPIC;
182     }
183     if (TT.isOSWindows() && is64Bit)
184       return Reloc::PIC_;
185     return Reloc::Static;
186   }
187 
188   // ELF and X86-64 don't have a distinct DynamicNoPIC model.  DynamicNoPIC
189   // is defined as a model for code which may be used in static or dynamic
190   // executables but not necessarily a shared library. On X86-32 we just
191   // compile in -static mode, in x86-64 we use PIC.
192   if (*RM == Reloc::DynamicNoPIC) {
193     if (is64Bit)
194       return Reloc::PIC_;
195     if (!TT.isOSDarwin())
196       return Reloc::Static;
197   }
198 
199   // If we are on Darwin, disallow static relocation model in X86-64 mode, since
200   // the Mach-O file format doesn't support it.
201   if (*RM == Reloc::Static && TT.isOSDarwin() && is64Bit)
202     return Reloc::PIC_;
203 
204   return *RM;
205 }
206 
207 static CodeModel::Model
208 getEffectiveX86CodeModel(std::optional<CodeModel::Model> CM, bool JIT,
209                          bool Is64Bit) {
210   if (CM) {
211     if (*CM == CodeModel::Tiny)
212       report_fatal_error("Target does not support the tiny CodeModel", false);
213     return *CM;
214   }
215   if (JIT)
216     return Is64Bit ? CodeModel::Large : CodeModel::Small;
217   return CodeModel::Small;
218 }
219 
220 /// Create an X86 target.
221 ///
222 X86TargetMachine::X86TargetMachine(const Target &T, const Triple &TT,
223                                    StringRef CPU, StringRef FS,
224                                    const TargetOptions &Options,
225                                    std::optional<Reloc::Model> RM,
226                                    std::optional<CodeModel::Model> CM,
227                                    CodeGenOpt::Level OL, bool JIT)
228     : LLVMTargetMachine(
229           T, computeDataLayout(TT), TT, CPU, FS, Options,
230           getEffectiveRelocModel(TT, JIT, RM),
231           getEffectiveX86CodeModel(CM, JIT, TT.getArch() == Triple::x86_64),
232           OL),
233       TLOF(createTLOF(getTargetTriple())), IsJIT(JIT) {
234   // On PS4/PS5, the "return address" of a 'noreturn' call must still be within
235   // the calling function, and TrapUnreachable is an easy way to get that.
236   if (TT.isPS() || TT.isOSBinFormatMachO()) {
237     this->Options.TrapUnreachable = true;
238     this->Options.NoTrapAfterNoreturn = TT.isOSBinFormatMachO();
239   }
240 
241   setMachineOutliner(true);
242 
243   // x86 supports the debug entry values.
244   setSupportsDebugEntryValues(true);
245 
246   initAsmInfo();
247 }
248 
249 X86TargetMachine::~X86TargetMachine() = default;
250 
251 const X86Subtarget *
252 X86TargetMachine::getSubtargetImpl(const Function &F) const {
253   Attribute CPUAttr = F.getFnAttribute("target-cpu");
254   Attribute TuneAttr = F.getFnAttribute("tune-cpu");
255   Attribute FSAttr = F.getFnAttribute("target-features");
256 
257   StringRef CPU =
258       CPUAttr.isValid() ? CPUAttr.getValueAsString() : (StringRef)TargetCPU;
259   // "x86-64" is a default target setting for many front ends. In these cases,
260   // they actually request for "generic" tuning unless the "tune-cpu" was
261   // specified.
262   StringRef TuneCPU = TuneAttr.isValid() ? TuneAttr.getValueAsString()
263                       : CPU == "x86-64"  ? "generic"
264                                          : (StringRef)CPU;
265   StringRef FS =
266       FSAttr.isValid() ? FSAttr.getValueAsString() : (StringRef)TargetFS;
267 
268   SmallString<512> Key;
269   // The additions here are ordered so that the definitely short strings are
270   // added first so we won't exceed the small size. We append the
271   // much longer FS string at the end so that we only heap allocate at most
272   // one time.
273 
274   // Extract prefer-vector-width attribute.
275   unsigned PreferVectorWidthOverride = 0;
276   Attribute PreferVecWidthAttr = F.getFnAttribute("prefer-vector-width");
277   if (PreferVecWidthAttr.isValid()) {
278     StringRef Val = PreferVecWidthAttr.getValueAsString();
279     unsigned Width;
280     if (!Val.getAsInteger(0, Width)) {
281       Key += 'p';
282       Key += Val;
283       PreferVectorWidthOverride = Width;
284     }
285   }
286 
287   // Extract min-legal-vector-width attribute.
288   unsigned RequiredVectorWidth = UINT32_MAX;
289   Attribute MinLegalVecWidthAttr = F.getFnAttribute("min-legal-vector-width");
290   if (MinLegalVecWidthAttr.isValid()) {
291     StringRef Val = MinLegalVecWidthAttr.getValueAsString();
292     unsigned Width;
293     if (!Val.getAsInteger(0, Width)) {
294       Key += 'm';
295       Key += Val;
296       RequiredVectorWidth = Width;
297     }
298   }
299 
300   // Add CPU to the Key.
301   Key += CPU;
302 
303   // Add tune CPU to the Key.
304   Key += TuneCPU;
305 
306   // Keep track of the start of the feature portion of the string.
307   unsigned FSStart = Key.size();
308 
309   // FIXME: This is related to the code below to reset the target options,
310   // we need to know whether or not the soft float flag is set on the
311   // function before we can generate a subtarget. We also need to use
312   // it as a key for the subtarget since that can be the only difference
313   // between two functions.
314   bool SoftFloat = F.getFnAttribute("use-soft-float").getValueAsBool();
315   // If the soft float attribute is set on the function turn on the soft float
316   // subtarget feature.
317   if (SoftFloat)
318     Key += FS.empty() ? "+soft-float" : "+soft-float,";
319 
320   Key += FS;
321 
322   // We may have added +soft-float to the features so move the StringRef to
323   // point to the full string in the Key.
324   FS = Key.substr(FSStart);
325 
326   auto &I = SubtargetMap[Key];
327   if (!I) {
328     // This needs to be done before we create a new subtarget since any
329     // creation will depend on the TM and the code generation flags on the
330     // function that reside in TargetOptions.
331     resetTargetOptions(F);
332     I = std::make_unique<X86Subtarget>(
333         TargetTriple, CPU, TuneCPU, FS, *this,
334         MaybeAlign(F.getParent()->getOverrideStackAlignment()),
335         PreferVectorWidthOverride, RequiredVectorWidth);
336   }
337   return I.get();
338 }
339 
340 bool X86TargetMachine::isNoopAddrSpaceCast(unsigned SrcAS,
341                                            unsigned DestAS) const {
342   assert(SrcAS != DestAS && "Expected different address spaces!");
343   if (getPointerSize(SrcAS) != getPointerSize(DestAS))
344     return false;
345   return SrcAS < 256 && DestAS < 256;
346 }
347 
348 //===----------------------------------------------------------------------===//
349 // X86 TTI query.
350 //===----------------------------------------------------------------------===//
351 
352 TargetTransformInfo
353 X86TargetMachine::getTargetTransformInfo(const Function &F) const {
354   return TargetTransformInfo(X86TTIImpl(this, F));
355 }
356 
357 //===----------------------------------------------------------------------===//
358 // Pass Pipeline Configuration
359 //===----------------------------------------------------------------------===//
360 
361 namespace {
362 
363 /// X86 Code Generator Pass Configuration Options.
364 class X86PassConfig : public TargetPassConfig {
365 public:
366   X86PassConfig(X86TargetMachine &TM, PassManagerBase &PM)
367     : TargetPassConfig(TM, PM) {}
368 
369   X86TargetMachine &getX86TargetMachine() const {
370     return getTM<X86TargetMachine>();
371   }
372 
373   ScheduleDAGInstrs *
374   createMachineScheduler(MachineSchedContext *C) const override {
375     ScheduleDAGMILive *DAG = createGenericSchedLive(C);
376     DAG->addMutation(createX86MacroFusionDAGMutation());
377     return DAG;
378   }
379 
380   ScheduleDAGInstrs *
381   createPostMachineScheduler(MachineSchedContext *C) const override {
382     ScheduleDAGMI *DAG = createGenericSchedPostRA(C);
383     DAG->addMutation(createX86MacroFusionDAGMutation());
384     return DAG;
385   }
386 
387   void addIRPasses() override;
388   bool addInstSelector() override;
389   bool addIRTranslator() override;
390   bool addLegalizeMachineIR() override;
391   bool addRegBankSelect() override;
392   bool addGlobalInstructionSelect() override;
393   bool addILPOpts() override;
394   bool addPreISel() override;
395   void addMachineSSAOptimization() override;
396   void addPreRegAlloc() override;
397   bool addPostFastRegAllocRewrite() override;
398   void addPostRegAlloc() override;
399   void addPreEmitPass() override;
400   void addPreEmitPass2() override;
401   void addPreSched2() override;
402   bool addRegAssignAndRewriteOptimized() override;
403 
404   std::unique_ptr<CSEConfigBase> getCSEConfig() const override;
405 };
406 
407 class X86ExecutionDomainFix : public ExecutionDomainFix {
408 public:
409   static char ID;
410   X86ExecutionDomainFix() : ExecutionDomainFix(ID, X86::VR128XRegClass) {}
411   StringRef getPassName() const override {
412     return "X86 Execution Dependency Fix";
413   }
414 };
415 char X86ExecutionDomainFix::ID;
416 
417 } // end anonymous namespace
418 
419 INITIALIZE_PASS_BEGIN(X86ExecutionDomainFix, "x86-execution-domain-fix",
420   "X86 Execution Domain Fix", false, false)
421 INITIALIZE_PASS_DEPENDENCY(ReachingDefAnalysis)
422 INITIALIZE_PASS_END(X86ExecutionDomainFix, "x86-execution-domain-fix",
423   "X86 Execution Domain Fix", false, false)
424 
425 TargetPassConfig *X86TargetMachine::createPassConfig(PassManagerBase &PM) {
426   return new X86PassConfig(*this, PM);
427 }
428 
429 MachineFunctionInfo *X86TargetMachine::createMachineFunctionInfo(
430     BumpPtrAllocator &Allocator, const Function &F,
431     const TargetSubtargetInfo *STI) const {
432   return X86MachineFunctionInfo::create<X86MachineFunctionInfo>(Allocator, F,
433                                                                 STI);
434 }
435 
436 void X86PassConfig::addIRPasses() {
437   addPass(createAtomicExpandPass());
438 
439   // We add both pass anyway and when these two passes run, we skip the pass
440   // based on the option level and option attribute.
441   addPass(createX86LowerAMXIntrinsicsPass());
442   addPass(createX86LowerAMXTypePass());
443 
444   TargetPassConfig::addIRPasses();
445 
446   if (TM->getOptLevel() != CodeGenOpt::None) {
447     addPass(createInterleavedAccessPass());
448     addPass(createX86PartialReductionPass());
449   }
450 
451   // Add passes that handle indirect branch removal and insertion of a retpoline
452   // thunk. These will be a no-op unless a function subtarget has the retpoline
453   // feature enabled.
454   addPass(createIndirectBrExpandPass());
455 
456   // Add Control Flow Guard checks.
457   const Triple &TT = TM->getTargetTriple();
458   if (TT.isOSWindows()) {
459     if (TT.getArch() == Triple::x86_64) {
460       addPass(createCFGuardDispatchPass());
461     } else {
462       addPass(createCFGuardCheckPass());
463     }
464   }
465 
466   if (TM->Options.JMCInstrument)
467     addPass(createJMCInstrumenterPass());
468 }
469 
470 bool X86PassConfig::addInstSelector() {
471   // Install an instruction selector.
472   addPass(createX86ISelDag(getX86TargetMachine(), getOptLevel()));
473 
474   // For ELF, cleanup any local-dynamic TLS accesses.
475   if (TM->getTargetTriple().isOSBinFormatELF() &&
476       getOptLevel() != CodeGenOpt::None)
477     addPass(createCleanupLocalDynamicTLSPass());
478 
479   addPass(createX86GlobalBaseRegPass());
480   addPass(createX86ArgumentStackSlotPass());
481   return false;
482 }
483 
484 bool X86PassConfig::addIRTranslator() {
485   addPass(new IRTranslator(getOptLevel()));
486   return false;
487 }
488 
489 bool X86PassConfig::addLegalizeMachineIR() {
490   addPass(new Legalizer());
491   return false;
492 }
493 
494 bool X86PassConfig::addRegBankSelect() {
495   addPass(new RegBankSelect());
496   return false;
497 }
498 
499 bool X86PassConfig::addGlobalInstructionSelect() {
500   addPass(new InstructionSelect(getOptLevel()));
501   return false;
502 }
503 
504 bool X86PassConfig::addILPOpts() {
505   addPass(&EarlyIfConverterID);
506   if (EnableMachineCombinerPass)
507     addPass(&MachineCombinerID);
508   addPass(createX86CmovConverterPass());
509   return true;
510 }
511 
512 bool X86PassConfig::addPreISel() {
513   // Only add this pass for 32-bit x86 Windows.
514   const Triple &TT = TM->getTargetTriple();
515   if (TT.isOSWindows() && TT.getArch() == Triple::x86)
516     addPass(createX86WinEHStatePass());
517   return true;
518 }
519 
520 void X86PassConfig::addPreRegAlloc() {
521   if (getOptLevel() != CodeGenOpt::None) {
522     addPass(&LiveRangeShrinkID);
523     addPass(createX86FixupSetCC());
524     addPass(createX86OptimizeLEAs());
525     addPass(createX86CallFrameOptimization());
526     addPass(createX86AvoidStoreForwardingBlocks());
527   }
528 
529   addPass(createX86SpeculativeLoadHardeningPass());
530   addPass(createX86FlagsCopyLoweringPass());
531   addPass(createX86DynAllocaExpander());
532 
533   if (getOptLevel() != CodeGenOpt::None)
534     addPass(createX86PreTileConfigPass());
535   else
536     addPass(createX86FastPreTileConfigPass());
537 }
538 
539 void X86PassConfig::addMachineSSAOptimization() {
540   addPass(createX86DomainReassignmentPass());
541   TargetPassConfig::addMachineSSAOptimization();
542 }
543 
544 void X86PassConfig::addPostRegAlloc() {
545   addPass(createX86LowerTileCopyPass());
546   addPass(createX86FloatingPointStackifierPass());
547   // When -O0 is enabled, the Load Value Injection Hardening pass will fall back
548   // to using the Speculative Execution Side Effect Suppression pass for
549   // mitigation. This is to prevent slow downs due to
550   // analyses needed by the LVIHardening pass when compiling at -O0.
551   if (getOptLevel() != CodeGenOpt::None)
552     addPass(createX86LoadValueInjectionLoadHardeningPass());
553 }
554 
555 void X86PassConfig::addPreSched2() {
556   addPass(createX86ExpandPseudoPass());
557   addPass(createKCFIPass());
558 }
559 
560 void X86PassConfig::addPreEmitPass() {
561   if (getOptLevel() != CodeGenOpt::None) {
562     addPass(new X86ExecutionDomainFix());
563     addPass(createBreakFalseDeps());
564   }
565 
566   addPass(createX86IndirectBranchTrackingPass());
567 
568   addPass(createX86IssueVZeroUpperPass());
569 
570   if (getOptLevel() != CodeGenOpt::None) {
571     addPass(createX86FixupBWInsts());
572     addPass(createX86PadShortFunctions());
573     addPass(createX86FixupLEAs());
574     addPass(createX86FixupInstTuning());
575     addPass(createX86FixupVectorConstants());
576   }
577   addPass(createX86EvexToVexInsts());
578   addPass(createX86DiscriminateMemOpsPass());
579   addPass(createX86InsertPrefetchPass());
580   addPass(createX86InsertX87waitPass());
581 }
582 
583 void X86PassConfig::addPreEmitPass2() {
584   const Triple &TT = TM->getTargetTriple();
585   const MCAsmInfo *MAI = TM->getMCAsmInfo();
586 
587   // The X86 Speculative Execution Pass must run after all control
588   // flow graph modifying passes. As a result it was listed to run right before
589   // the X86 Retpoline Thunks pass. The reason it must run after control flow
590   // graph modifications is that the model of LFENCE in LLVM has to be updated
591   // (FIXME: https://bugs.llvm.org/show_bug.cgi?id=45167). Currently the
592   // placement of this pass was hand checked to ensure that the subsequent
593   // passes don't move the code around the LFENCEs in a way that will hurt the
594   // correctness of this pass. This placement has been shown to work based on
595   // hand inspection of the codegen output.
596   addPass(createX86SpeculativeExecutionSideEffectSuppression());
597   addPass(createX86IndirectThunksPass());
598   addPass(createX86ReturnThunksPass());
599 
600   // Insert extra int3 instructions after trailing call instructions to avoid
601   // issues in the unwinder.
602   if (TT.isOSWindows() && TT.getArch() == Triple::x86_64)
603     addPass(createX86AvoidTrailingCallPass());
604 
605   // Verify basic block incoming and outgoing cfa offset and register values and
606   // correct CFA calculation rule where needed by inserting appropriate CFI
607   // instructions.
608   if (!TT.isOSDarwin() &&
609       (!TT.isOSWindows() ||
610        MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI))
611     addPass(createCFIInstrInserter());
612 
613   if (TT.isOSWindows()) {
614     // Identify valid longjmp targets for Windows Control Flow Guard.
615     addPass(createCFGuardLongjmpPass());
616     // Identify valid eh continuation targets for Windows EHCont Guard.
617     addPass(createEHContGuardCatchretPass());
618   }
619   addPass(createX86LoadValueInjectionRetHardeningPass());
620 
621   // Insert pseudo probe annotation for callsite profiling
622   addPass(createPseudoProbeInserter());
623 
624   // KCFI indirect call checks are lowered to a bundle, and on Darwin platforms,
625   // also CALL_RVMARKER.
626   addPass(createUnpackMachineBundles([&TT](const MachineFunction &MF) {
627     // Only run bundle expansion if the module uses kcfi, or there are relevant
628     // ObjC runtime functions present in the module.
629     const Function &F = MF.getFunction();
630     const Module *M = F.getParent();
631     return M->getModuleFlag("kcfi") ||
632            (TT.isOSDarwin() &&
633             (M->getFunction("objc_retainAutoreleasedReturnValue") ||
634              M->getFunction("objc_unsafeClaimAutoreleasedReturnValue")));
635   }));
636 }
637 
638 bool X86PassConfig::addPostFastRegAllocRewrite() {
639   addPass(createX86FastTileConfigPass());
640   return true;
641 }
642 
643 std::unique_ptr<CSEConfigBase> X86PassConfig::getCSEConfig() const {
644   return getStandardCSEConfigForOpt(TM->getOptLevel());
645 }
646 
647 static bool onlyAllocateTileRegisters(const TargetRegisterInfo &TRI,
648                                       const TargetRegisterClass &RC) {
649   return static_cast<const X86RegisterInfo &>(TRI).isTileRegisterClass(&RC);
650 }
651 
652 bool X86PassConfig::addRegAssignAndRewriteOptimized() {
653   // Don't support tile RA when RA is specified by command line "-regalloc".
654   if (!isCustomizedRegAlloc() && EnableTileRAPass) {
655     // Allocate tile register first.
656     addPass(createGreedyRegisterAllocator(onlyAllocateTileRegisters));
657     addPass(createX86TileConfigPass());
658   }
659   return TargetPassConfig::addRegAssignAndRewriteOptimized();
660 }
661