xref: /llvm-project/llvm/tools/llvm-reduce/ReducerWorkItem.cpp (revision a8f8613dec435cfb78bf202c392f2acf150a5937) 
1 //===- ReducerWorkItem.cpp - Wrapper for Module and MachineFunction -------===//
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 #include "ReducerWorkItem.h"
10 #include "TestRunner.h"
11 #include "llvm/Analysis/ModuleSummaryAnalysis.h"
12 #include "llvm/Analysis/ProfileSummaryInfo.h"
13 #include "llvm/Bitcode/BitcodeReader.h"
14 #include "llvm/Bitcode/BitcodeWriter.h"
15 #include "llvm/CodeGen/CommandFlags.h"
16 #include "llvm/CodeGen/MIRParser/MIRParser.h"
17 #include "llvm/CodeGen/MIRPrinter.h"
18 #include "llvm/CodeGen/MachineDominators.h"
19 #include "llvm/CodeGen/MachineFrameInfo.h"
20 #include "llvm/CodeGen/MachineFunction.h"
21 #include "llvm/CodeGen/MachineFunctionPass.h"
22 #include "llvm/CodeGen/MachineModuleInfo.h"
23 #include "llvm/CodeGen/MachineRegisterInfo.h"
24 #include "llvm/CodeGen/TargetInstrInfo.h"
25 #include "llvm/IR/Constants.h"
26 #include "llvm/IR/Instructions.h"
27 #include "llvm/IR/ModuleSummaryIndex.h"
28 #include "llvm/IR/Operator.h"
29 #include "llvm/IR/Verifier.h"
30 #include "llvm/IRReader/IRReader.h"
31 #include "llvm/MC/TargetRegistry.h"
32 #include "llvm/Passes/PassBuilder.h"
33 #include "llvm/Support/MemoryBufferRef.h"
34 #include "llvm/Support/SourceMgr.h"
35 #include "llvm/Support/TargetSelect.h"
36 #include "llvm/Support/ToolOutputFile.h"
37 #include "llvm/Support/WithColor.h"
38 #include "llvm/Target/TargetMachine.h"
39 #include "llvm/TargetParser/Host.h"
40 #include "llvm/Transforms/IPO/ThinLTOBitcodeWriter.h"
41 #include "llvm/Transforms/Utils/Cloning.h"
42 #include <optional>
43 
44 using namespace llvm;
45 
46 ReducerWorkItem::ReducerWorkItem() = default;
47 ReducerWorkItem::~ReducerWorkItem() = default;
48 
49 extern cl::OptionCategory LLVMReduceOptions;
50 static cl::opt<std::string> TargetTriple("mtriple",
51                                          cl::desc("Set the target triple"),
52                                          cl::cat(LLVMReduceOptions));
53 
54 static cl::opt<bool> TmpFilesAsBitcode(
55     "write-tmp-files-as-bitcode",
56     cl::desc("Always write temporary files as bitcode instead of textual IR"),
57     cl::init(false), cl::cat(LLVMReduceOptions));
58 
59 static void cloneFrameInfo(
60     MachineFrameInfo &DstMFI, const MachineFrameInfo &SrcMFI,
61     const DenseMap<MachineBasicBlock *, MachineBasicBlock *> &Src2DstMBB) {
62   DstMFI.setFrameAddressIsTaken(SrcMFI.isFrameAddressTaken());
63   DstMFI.setReturnAddressIsTaken(SrcMFI.isReturnAddressTaken());
64   DstMFI.setHasStackMap(SrcMFI.hasStackMap());
65   DstMFI.setHasPatchPoint(SrcMFI.hasPatchPoint());
66   DstMFI.setUseLocalStackAllocationBlock(
67       SrcMFI.getUseLocalStackAllocationBlock());
68   DstMFI.setOffsetAdjustment(SrcMFI.getOffsetAdjustment());
69 
70   DstMFI.ensureMaxAlignment(SrcMFI.getMaxAlign());
71   assert(DstMFI.getMaxAlign() == SrcMFI.getMaxAlign() &&
72          "we need to set exact alignment");
73 
74   DstMFI.setAdjustsStack(SrcMFI.adjustsStack());
75   DstMFI.setHasCalls(SrcMFI.hasCalls());
76   DstMFI.setHasOpaqueSPAdjustment(SrcMFI.hasOpaqueSPAdjustment());
77   DstMFI.setHasCopyImplyingStackAdjustment(
78       SrcMFI.hasCopyImplyingStackAdjustment());
79   DstMFI.setHasVAStart(SrcMFI.hasVAStart());
80   DstMFI.setHasMustTailInVarArgFunc(SrcMFI.hasMustTailInVarArgFunc());
81   DstMFI.setHasTailCall(SrcMFI.hasTailCall());
82 
83   if (SrcMFI.isMaxCallFrameSizeComputed())
84     DstMFI.setMaxCallFrameSize(SrcMFI.getMaxCallFrameSize());
85 
86   DstMFI.setCVBytesOfCalleeSavedRegisters(
87       SrcMFI.getCVBytesOfCalleeSavedRegisters());
88 
89   if (MachineBasicBlock *SavePt = SrcMFI.getSavePoint())
90     DstMFI.setSavePoint(Src2DstMBB.find(SavePt)->second);
91   if (MachineBasicBlock *RestorePt = SrcMFI.getRestorePoint())
92     DstMFI.setRestorePoint(Src2DstMBB.find(RestorePt)->second);
93 
94 
95   auto CopyObjectProperties = [](MachineFrameInfo &DstMFI,
96                                  const MachineFrameInfo &SrcMFI, int FI) {
97     if (SrcMFI.isStatepointSpillSlotObjectIndex(FI))
98       DstMFI.markAsStatepointSpillSlotObjectIndex(FI);
99     DstMFI.setObjectSSPLayout(FI, SrcMFI.getObjectSSPLayout(FI));
100     DstMFI.setObjectZExt(FI, SrcMFI.isObjectZExt(FI));
101     DstMFI.setObjectSExt(FI, SrcMFI.isObjectSExt(FI));
102   };
103 
104   for (int i = 0, e = SrcMFI.getNumObjects() - SrcMFI.getNumFixedObjects();
105        i != e; ++i) {
106     int NewFI;
107 
108     assert(!SrcMFI.isFixedObjectIndex(i));
109     if (SrcMFI.isVariableSizedObjectIndex(i)) {
110       NewFI = DstMFI.CreateVariableSizedObject(SrcMFI.getObjectAlign(i),
111                                                SrcMFI.getObjectAllocation(i));
112     } else {
113       NewFI = DstMFI.CreateStackObject(
114           SrcMFI.getObjectSize(i), SrcMFI.getObjectAlign(i),
115           SrcMFI.isSpillSlotObjectIndex(i), SrcMFI.getObjectAllocation(i),
116           SrcMFI.getStackID(i));
117       DstMFI.setObjectOffset(NewFI, SrcMFI.getObjectOffset(i));
118     }
119 
120     CopyObjectProperties(DstMFI, SrcMFI, i);
121 
122     (void)NewFI;
123     assert(i == NewFI && "expected to keep stable frame index numbering");
124   }
125 
126   // Copy the fixed frame objects backwards to preserve frame index numbers,
127   // since CreateFixedObject uses front insertion.
128   for (int i = -1; i >= (int)-SrcMFI.getNumFixedObjects(); --i) {
129     assert(SrcMFI.isFixedObjectIndex(i));
130     int NewFI = DstMFI.CreateFixedObject(
131       SrcMFI.getObjectSize(i), SrcMFI.getObjectOffset(i),
132       SrcMFI.isImmutableObjectIndex(i), SrcMFI.isAliasedObjectIndex(i));
133     CopyObjectProperties(DstMFI, SrcMFI, i);
134 
135     (void)NewFI;
136     assert(i == NewFI && "expected to keep stable frame index numbering");
137   }
138 
139   for (unsigned I = 0, E = SrcMFI.getLocalFrameObjectCount(); I < E; ++I) {
140     auto LocalObject = SrcMFI.getLocalFrameObjectMap(I);
141     DstMFI.mapLocalFrameObject(LocalObject.first, LocalObject.second);
142   }
143 
144   DstMFI.setCalleeSavedInfo(SrcMFI.getCalleeSavedInfo());
145 
146   if (SrcMFI.hasStackProtectorIndex()) {
147     DstMFI.setStackProtectorIndex(SrcMFI.getStackProtectorIndex());
148   }
149 
150   // FIXME: Needs test, missing MIR serialization.
151   if (SrcMFI.hasFunctionContextIndex()) {
152     DstMFI.setFunctionContextIndex(SrcMFI.getFunctionContextIndex());
153   }
154 }
155 
156 static void cloneMemOperands(MachineInstr &DstMI, MachineInstr &SrcMI,
157                              MachineFunction &SrcMF, MachineFunction &DstMF) {
158   // The new MachineMemOperands should be owned by the new function's
159   // Allocator.
160   PseudoSourceValueManager &PSVMgr = DstMF.getPSVManager();
161 
162   // We also need to remap the PseudoSourceValues from the new function's
163   // PseudoSourceValueManager.
164   SmallVector<MachineMemOperand *, 2> NewMMOs;
165   for (MachineMemOperand *OldMMO : SrcMI.memoperands()) {
166     MachinePointerInfo NewPtrInfo(OldMMO->getPointerInfo());
167     if (const PseudoSourceValue *PSV =
168             dyn_cast_if_present<const PseudoSourceValue *>(NewPtrInfo.V)) {
169       switch (PSV->kind()) {
170       case PseudoSourceValue::Stack:
171         NewPtrInfo.V = PSVMgr.getStack();
172         break;
173       case PseudoSourceValue::GOT:
174         NewPtrInfo.V = PSVMgr.getGOT();
175         break;
176       case PseudoSourceValue::JumpTable:
177         NewPtrInfo.V = PSVMgr.getJumpTable();
178         break;
179       case PseudoSourceValue::ConstantPool:
180         NewPtrInfo.V = PSVMgr.getConstantPool();
181         break;
182       case PseudoSourceValue::FixedStack:
183         NewPtrInfo.V = PSVMgr.getFixedStack(
184             cast<FixedStackPseudoSourceValue>(PSV)->getFrameIndex());
185         break;
186       case PseudoSourceValue::GlobalValueCallEntry:
187         NewPtrInfo.V = PSVMgr.getGlobalValueCallEntry(
188             cast<GlobalValuePseudoSourceValue>(PSV)->getValue());
189         break;
190       case PseudoSourceValue::ExternalSymbolCallEntry:
191         NewPtrInfo.V = PSVMgr.getExternalSymbolCallEntry(
192             cast<ExternalSymbolPseudoSourceValue>(PSV)->getSymbol());
193         break;
194       case PseudoSourceValue::TargetCustom:
195       default:
196         // FIXME: We have no generic interface for allocating custom PSVs.
197         report_fatal_error("Cloning TargetCustom PSV not handled");
198       }
199     }
200 
201     MachineMemOperand *NewMMO = DstMF.getMachineMemOperand(
202         NewPtrInfo, OldMMO->getFlags(), OldMMO->getMemoryType(),
203         OldMMO->getBaseAlign(), OldMMO->getAAInfo(), OldMMO->getRanges(),
204         OldMMO->getSyncScopeID(), OldMMO->getSuccessOrdering(),
205         OldMMO->getFailureOrdering());
206     NewMMOs.push_back(NewMMO);
207   }
208 
209   DstMI.setMemRefs(DstMF, NewMMOs);
210 }
211 
212 static std::unique_ptr<MachineFunction> cloneMF(MachineFunction *SrcMF,
213                                                 MachineModuleInfo &DestMMI) {
214   auto DstMF = std::make_unique<MachineFunction>(
215       SrcMF->getFunction(), SrcMF->getTarget(), SrcMF->getSubtarget(),
216       SrcMF->getFunctionNumber(), DestMMI);
217   DenseMap<MachineBasicBlock *, MachineBasicBlock *> Src2DstMBB;
218 
219   auto *SrcMRI = &SrcMF->getRegInfo();
220   auto *DstMRI = &DstMF->getRegInfo();
221 
222   // Clone blocks.
223   for (MachineBasicBlock &SrcMBB : *SrcMF) {
224     MachineBasicBlock *DstMBB =
225         DstMF->CreateMachineBasicBlock(SrcMBB.getBasicBlock());
226     Src2DstMBB[&SrcMBB] = DstMBB;
227 
228     DstMBB->setCallFrameSize(SrcMBB.getCallFrameSize());
229 
230     if (SrcMBB.isIRBlockAddressTaken())
231       DstMBB->setAddressTakenIRBlock(SrcMBB.getAddressTakenIRBlock());
232     if (SrcMBB.isMachineBlockAddressTaken())
233       DstMBB->setMachineBlockAddressTaken();
234 
235     // FIXME: This is not serialized
236     if (SrcMBB.hasLabelMustBeEmitted())
237       DstMBB->setLabelMustBeEmitted();
238 
239     DstMBB->setAlignment(SrcMBB.getAlignment());
240 
241     // FIXME: This is not serialized
242     DstMBB->setMaxBytesForAlignment(SrcMBB.getMaxBytesForAlignment());
243 
244     DstMBB->setIsEHPad(SrcMBB.isEHPad());
245     DstMBB->setIsEHScopeEntry(SrcMBB.isEHScopeEntry());
246     DstMBB->setIsEHCatchretTarget(SrcMBB.isEHCatchretTarget());
247     DstMBB->setIsEHFuncletEntry(SrcMBB.isEHFuncletEntry());
248 
249     // FIXME: These are not serialized
250     DstMBB->setIsCleanupFuncletEntry(SrcMBB.isCleanupFuncletEntry());
251     DstMBB->setIsBeginSection(SrcMBB.isBeginSection());
252     DstMBB->setIsEndSection(SrcMBB.isEndSection());
253 
254     DstMBB->setSectionID(SrcMBB.getSectionID());
255     DstMBB->setIsInlineAsmBrIndirectTarget(
256         SrcMBB.isInlineAsmBrIndirectTarget());
257 
258     // FIXME: This is not serialized
259     if (std::optional<uint64_t> Weight = SrcMBB.getIrrLoopHeaderWeight())
260       DstMBB->setIrrLoopHeaderWeight(*Weight);
261   }
262 
263   const MachineFrameInfo &SrcMFI = SrcMF->getFrameInfo();
264   MachineFrameInfo &DstMFI = DstMF->getFrameInfo();
265 
266   // Copy stack objects and other info
267   cloneFrameInfo(DstMFI, SrcMFI, Src2DstMBB);
268 
269   // Remap the debug info frame index references.
270   DstMF->VariableDbgInfos = SrcMF->VariableDbgInfos;
271 
272   // Clone virtual registers
273   for (unsigned I = 0, E = SrcMRI->getNumVirtRegs(); I != E; ++I) {
274     Register Reg = Register::index2VirtReg(I);
275     Register NewReg = DstMRI->createIncompleteVirtualRegister(
276       SrcMRI->getVRegName(Reg));
277     assert(NewReg == Reg && "expected to preserve virtreg number");
278 
279     DstMRI->setRegClassOrRegBank(NewReg, SrcMRI->getRegClassOrRegBank(Reg));
280 
281     LLT RegTy = SrcMRI->getType(Reg);
282     if (RegTy.isValid())
283       DstMRI->setType(NewReg, RegTy);
284 
285     // Copy register allocation hints.
286     const auto &Hints = SrcMRI->getRegAllocationHints(Reg);
287     for (Register PrefReg : Hints.second)
288       DstMRI->addRegAllocationHint(NewReg, PrefReg);
289   }
290 
291   const TargetSubtargetInfo &STI = DstMF->getSubtarget();
292   const TargetInstrInfo *TII = STI.getInstrInfo();
293   const TargetRegisterInfo *TRI = STI.getRegisterInfo();
294 
295   // Link blocks.
296   for (auto &SrcMBB : *SrcMF) {
297     auto *DstMBB = Src2DstMBB[&SrcMBB];
298     DstMF->push_back(DstMBB);
299 
300     for (auto It = SrcMBB.succ_begin(), IterEnd = SrcMBB.succ_end();
301          It != IterEnd; ++It) {
302       auto *SrcSuccMBB = *It;
303       auto *DstSuccMBB = Src2DstMBB[SrcSuccMBB];
304       DstMBB->addSuccessor(DstSuccMBB, SrcMBB.getSuccProbability(It));
305     }
306 
307     for (auto &LI : SrcMBB.liveins_dbg())
308       DstMBB->addLiveIn(LI);
309 
310     // Make sure MRI knows about registers clobbered by unwinder.
311     if (DstMBB->isEHPad()) {
312       if (auto *RegMask = TRI->getCustomEHPadPreservedMask(*DstMF))
313         DstMRI->addPhysRegsUsedFromRegMask(RegMask);
314     }
315   }
316 
317   DenseSet<const uint32_t *> ConstRegisterMasks;
318 
319   // Track predefined/named regmasks which we ignore.
320   for (const uint32_t *Mask : TRI->getRegMasks())
321     ConstRegisterMasks.insert(Mask);
322 
323   // Clone instructions.
324   for (auto &SrcMBB : *SrcMF) {
325     auto *DstMBB = Src2DstMBB[&SrcMBB];
326     for (auto &SrcMI : SrcMBB) {
327       const auto &MCID = TII->get(SrcMI.getOpcode());
328       auto *DstMI = DstMF->CreateMachineInstr(MCID, SrcMI.getDebugLoc(),
329                                               /*NoImplicit=*/true);
330       DstMI->setFlags(SrcMI.getFlags());
331       DstMI->setAsmPrinterFlag(SrcMI.getAsmPrinterFlags());
332 
333       DstMBB->push_back(DstMI);
334       for (auto &SrcMO : SrcMI.operands()) {
335         MachineOperand DstMO(SrcMO);
336         DstMO.clearParent();
337 
338         // Update MBB.
339         if (DstMO.isMBB())
340           DstMO.setMBB(Src2DstMBB[DstMO.getMBB()]);
341         else if (DstMO.isRegMask()) {
342           DstMRI->addPhysRegsUsedFromRegMask(DstMO.getRegMask());
343 
344           if (!ConstRegisterMasks.count(DstMO.getRegMask())) {
345             uint32_t *DstMask = DstMF->allocateRegMask();
346             std::memcpy(DstMask, SrcMO.getRegMask(),
347                         sizeof(*DstMask) *
348                             MachineOperand::getRegMaskSize(TRI->getNumRegs()));
349             DstMO.setRegMask(DstMask);
350           }
351         }
352 
353         DstMI->addOperand(DstMO);
354       }
355 
356       cloneMemOperands(*DstMI, SrcMI, *SrcMF, *DstMF);
357     }
358   }
359 
360   DstMF->setAlignment(SrcMF->getAlignment());
361   DstMF->setExposesReturnsTwice(SrcMF->exposesReturnsTwice());
362   DstMF->setHasInlineAsm(SrcMF->hasInlineAsm());
363   DstMF->setHasWinCFI(SrcMF->hasWinCFI());
364 
365   DstMF->getProperties().reset().set(SrcMF->getProperties());
366 
367   if (!SrcMF->getFrameInstructions().empty() ||
368       !SrcMF->getLongjmpTargets().empty() ||
369       !SrcMF->getCatchretTargets().empty())
370     report_fatal_error("cloning not implemented for machine function property");
371 
372   DstMF->setCallsEHReturn(SrcMF->callsEHReturn());
373   DstMF->setCallsUnwindInit(SrcMF->callsUnwindInit());
374   DstMF->setHasEHCatchret(SrcMF->hasEHCatchret());
375   DstMF->setHasEHScopes(SrcMF->hasEHScopes());
376   DstMF->setHasEHFunclets(SrcMF->hasEHFunclets());
377   DstMF->setIsOutlined(SrcMF->isOutlined());
378 
379   if (!SrcMF->getLandingPads().empty() ||
380       !SrcMF->getCodeViewAnnotations().empty() ||
381       !SrcMF->getTypeInfos().empty() ||
382       !SrcMF->getFilterIds().empty() ||
383       SrcMF->hasAnyWasmLandingPadIndex() ||
384       SrcMF->hasAnyCallSiteLandingPad() ||
385       SrcMF->hasAnyCallSiteLabel() ||
386       !SrcMF->getCallSitesInfo().empty())
387     report_fatal_error("cloning not implemented for machine function property");
388 
389   DstMF->setDebugInstrNumberingCount(SrcMF->DebugInstrNumberingCount);
390 
391   if (!DstMF->cloneInfoFrom(*SrcMF, Src2DstMBB))
392     report_fatal_error("target does not implement MachineFunctionInfo cloning");
393 
394   DstMRI->freezeReservedRegs(*DstMF);
395 
396   DstMF->verify(nullptr, "", /*AbortOnError=*/true);
397   return DstMF;
398 }
399 
400 static void initializeTargetInfo() {
401   InitializeAllTargets();
402   InitializeAllTargetMCs();
403   InitializeAllAsmPrinters();
404   InitializeAllAsmParsers();
405 }
406 
407 void ReducerWorkItem::print(raw_ostream &ROS, void *p) const {
408   if (MMI) {
409     printMIR(ROS, *M);
410     for (Function &F : *M) {
411       if (auto *MF = MMI->getMachineFunction(F))
412         printMIR(ROS, *MF);
413     }
414   } else {
415     M->print(ROS, /*AssemblyAnnotationWriter=*/nullptr,
416              /*ShouldPreserveUseListOrder=*/true);
417   }
418 }
419 
420 bool ReducerWorkItem::verify(raw_fd_ostream *OS) const {
421   if (verifyModule(*M, OS))
422     return true;
423 
424   if (!MMI)
425     return false;
426 
427   for (const Function &F : getModule()) {
428     if (const MachineFunction *MF = MMI->getMachineFunction(F)) {
429       if (!MF->verify(nullptr, "", /*AbortOnError=*/false))
430         return true;
431     }
432   }
433 
434   return false;
435 }
436 
437 bool ReducerWorkItem::isReduced(const TestRunner &Test) const {
438   const bool UseBitcode = Test.inputIsBitcode() || TmpFilesAsBitcode;
439 
440   SmallString<128> CurrentFilepath;
441 
442   // Write ReducerWorkItem to tmp file
443   int FD;
444   std::error_code EC = sys::fs::createTemporaryFile(
445       "llvm-reduce", isMIR() ? "mir" : (UseBitcode ? "bc" : "ll"), FD,
446       CurrentFilepath,
447       UseBitcode && !isMIR() ? sys::fs::OF_None : sys::fs::OF_Text);
448   if (EC) {
449     WithColor::error(errs(), Test.getToolName())
450         << "error making unique filename: " << EC.message() << '\n';
451     exit(1);
452   }
453 
454   ToolOutputFile Out(CurrentFilepath, FD);
455 
456   writeOutput(Out.os(), UseBitcode);
457 
458   Out.os().close();
459   if (Out.os().has_error()) {
460     WithColor::error(errs(), Test.getToolName())
461         << "error emitting bitcode to file '" << CurrentFilepath
462         << "': " << Out.os().error().message() << '\n';
463     exit(1);
464   }
465 
466   // Current Chunks aren't interesting
467   return Test.run(CurrentFilepath);
468 }
469 
470 std::unique_ptr<ReducerWorkItem>
471 ReducerWorkItem::clone(const TargetMachine *TM) const {
472   auto CloneMMM = std::make_unique<ReducerWorkItem>();
473   if (TM) {
474     // We're assuming the Module IR contents are always unchanged by MIR
475     // reductions, and can share it as a constant.
476     CloneMMM->M = M;
477 
478     // MachineModuleInfo contains a lot of other state used during codegen which
479     // we won't be using here, but we should be able to ignore it (although this
480     // is pretty ugly).
481     const LLVMTargetMachine *LLVMTM =
482         static_cast<const LLVMTargetMachine *>(TM);
483     CloneMMM->MMI = std::make_unique<MachineModuleInfo>(LLVMTM);
484 
485     for (const Function &F : getModule()) {
486       if (auto *MF = MMI->getMachineFunction(F))
487         CloneMMM->MMI->insertFunction(F, cloneMF(MF, *CloneMMM->MMI));
488     }
489   } else {
490     CloneMMM->M = CloneModule(*M);
491   }
492   return CloneMMM;
493 }
494 
495 /// Try to produce some number that indicates a function is getting smaller /
496 /// simpler.
497 static uint64_t computeMIRComplexityScoreImpl(const MachineFunction &MF) {
498   uint64_t Score = 0;
499   const MachineFrameInfo &MFI = MF.getFrameInfo();
500 
501   // Add for stack objects
502   Score += MFI.getNumObjects();
503 
504   // Add in the block count.
505   Score += 2 * MF.size();
506 
507   const MachineRegisterInfo &MRI = MF.getRegInfo();
508   for (unsigned I = 0, E = MRI.getNumVirtRegs(); I != E; ++I) {
509     Register Reg = Register::index2VirtReg(I);
510     Score += MRI.getRegAllocationHints(Reg).second.size();
511   }
512 
513   for (const MachineBasicBlock &MBB : MF) {
514     for (const MachineInstr &MI : MBB) {
515       const unsigned Opc = MI.getOpcode();
516 
517       // Reductions may want or need to introduce implicit_defs, so don't count
518       // them.
519       // TODO: These probably should count in some way.
520       if (Opc == TargetOpcode::IMPLICIT_DEF ||
521           Opc == TargetOpcode::G_IMPLICIT_DEF)
522         continue;
523 
524       // Each instruction adds to the score
525       Score += 4;
526 
527       if (Opc == TargetOpcode::PHI || Opc == TargetOpcode::G_PHI ||
528           Opc == TargetOpcode::INLINEASM || Opc == TargetOpcode::INLINEASM_BR)
529         ++Score;
530 
531       if (MI.getFlags() != 0)
532         ++Score;
533 
534       // Increase weight for more operands.
535       for (const MachineOperand &MO : MI.operands()) {
536         ++Score;
537 
538         // Treat registers as more complex.
539         if (MO.isReg()) {
540           ++Score;
541 
542           // And subregisters as even more complex.
543           if (MO.getSubReg()) {
544             ++Score;
545             if (MO.isDef())
546               ++Score;
547           }
548         } else if (MO.isRegMask())
549           ++Score;
550       }
551     }
552   }
553 
554   return Score;
555 }
556 
557 uint64_t ReducerWorkItem::computeMIRComplexityScore() const {
558   uint64_t Score = 0;
559 
560   for (const Function &F : getModule()) {
561     if (auto *MF = MMI->getMachineFunction(F))
562       Score += computeMIRComplexityScoreImpl(*MF);
563   }
564 
565   return Score;
566 }
567 
568 // FIXME: ReduceOperandsSkip has similar function, except it uses larger numbers
569 // for more reduced.
570 static unsigned classifyReductivePower(const Value *V) {
571   if (auto *C = dyn_cast<ConstantData>(V)) {
572     if (C->isNullValue())
573       return 0;
574     if (C->isOneValue())
575       return 1;
576     if (isa<UndefValue>(V))
577       return 2;
578     return 3;
579   }
580 
581   if (isa<GlobalValue>(V))
582     return 4;
583 
584   // TODO: Account for expression size
585   if (isa<ConstantExpr>(V))
586     return 5;
587 
588   if (isa<Constant>(V))
589     return 1;
590 
591   if (isa<Argument>(V))
592     return 6;
593 
594   if (isa<Instruction>(V))
595     return 7;
596 
597   return 0;
598 }
599 
600 // TODO: Additional flags and attributes may be complexity reducing. If we start
601 // adding flags and attributes, they could have negative cost.
602 static uint64_t computeIRComplexityScoreImpl(const Function &F) {
603   uint64_t Score = 1; // Count the function itself
604   SmallVector<std::pair<unsigned, MDNode *>> MDs;
605 
606   AttributeList Attrs = F.getAttributes();
607   for (AttributeSet AttrSet : Attrs)
608     Score += AttrSet.getNumAttributes();
609 
610   for (const BasicBlock &BB : F) {
611     ++Score;
612 
613     for (const Instruction &I : BB) {
614       ++Score;
615 
616       if (const auto *OverflowOp = dyn_cast<OverflowingBinaryOperator>(&I)) {
617         if (OverflowOp->hasNoUnsignedWrap())
618           ++Score;
619         if (OverflowOp->hasNoSignedWrap())
620           ++Score;
621       } else if (const auto *GEP = dyn_cast<GEPOperator>(&I)) {
622         if (GEP->isInBounds())
623           ++Score;
624       } else if (const auto *ExactOp = dyn_cast<PossiblyExactOperator>(&I)) {
625         if (ExactOp->isExact())
626           ++Score;
627       } else if (const auto *FPOp = dyn_cast<FPMathOperator>(&I)) {
628         FastMathFlags FMF = FPOp->getFastMathFlags();
629         if (FMF.allowReassoc())
630           ++Score;
631         if (FMF.noNaNs())
632           ++Score;
633         if (FMF.noInfs())
634           ++Score;
635         if (FMF.noSignedZeros())
636           ++Score;
637         if (FMF.allowReciprocal())
638           ++Score;
639         if (FMF.allowContract())
640           ++Score;
641         if (FMF.approxFunc())
642           ++Score;
643       }
644 
645       for (const Value *Operand : I.operands()) {
646         ++Score;
647         Score += classifyReductivePower(Operand);
648       }
649 
650       I.getAllMetadata(MDs);
651       Score += MDs.size();
652       MDs.clear();
653     }
654   }
655 
656   return Score;
657 }
658 
659 uint64_t ReducerWorkItem::computeIRComplexityScore() const {
660   uint64_t Score = 0;
661 
662   const Module &M = getModule();
663   Score += M.named_metadata_size();
664 
665   SmallVector<std::pair<unsigned, MDNode *>, 32> GlobalMetadata;
666   for (const GlobalVariable &GV : M.globals()) {
667     ++Score;
668 
669     if (GV.hasInitializer())
670       Score += classifyReductivePower(GV.getInitializer());
671 
672     // TODO: Account for linkage?
673 
674     GV.getAllMetadata(GlobalMetadata);
675     Score += GlobalMetadata.size();
676     GlobalMetadata.clear();
677   }
678 
679   for (const GlobalAlias &GA : M.aliases())
680     Score += classifyReductivePower(GA.getAliasee());
681 
682   for (const GlobalIFunc &GI : M.ifuncs())
683     Score += classifyReductivePower(GI.getResolver());
684 
685   for (const Function &F : M)
686     Score += computeIRComplexityScoreImpl(F);
687 
688   return Score;
689 }
690 
691 void ReducerWorkItem::writeOutput(raw_ostream &OS, bool EmitBitcode) const {
692   // Requesting bitcode emission with mir is nonsense, so just ignore it.
693   if (EmitBitcode && !isMIR())
694     writeBitcode(OS);
695   else
696     print(OS, /*AnnotationWriter=*/nullptr);
697 }
698 
699 void ReducerWorkItem::readBitcode(MemoryBufferRef Data, LLVMContext &Ctx,
700                                   StringRef ToolName) {
701   Expected<BitcodeFileContents> IF = llvm::getBitcodeFileContents(Data);
702   if (!IF) {
703     WithColor::error(errs(), ToolName) << IF.takeError();
704     exit(1);
705   }
706   BitcodeModule BM = IF->Mods[0];
707   Expected<BitcodeLTOInfo> LI = BM.getLTOInfo();
708   Expected<std::unique_ptr<Module>> MOrErr = BM.parseModule(Ctx);
709   if (!LI || !MOrErr) {
710     WithColor::error(errs(), ToolName) << IF.takeError();
711     exit(1);
712   }
713   LTOInfo = std::make_unique<BitcodeLTOInfo>(*LI);
714   M = std::move(MOrErr.get());
715 }
716 
717 void ReducerWorkItem::writeBitcode(raw_ostream &OutStream) const {
718   if (LTOInfo && LTOInfo->IsThinLTO && LTOInfo->EnableSplitLTOUnit) {
719     PassBuilder PB;
720     LoopAnalysisManager LAM;
721     FunctionAnalysisManager FAM;
722     CGSCCAnalysisManager CGAM;
723     ModuleAnalysisManager MAM;
724     PB.registerModuleAnalyses(MAM);
725     PB.registerCGSCCAnalyses(CGAM);
726     PB.registerFunctionAnalyses(FAM);
727     PB.registerLoopAnalyses(LAM);
728     PB.crossRegisterProxies(LAM, FAM, CGAM, MAM);
729     ModulePassManager MPM;
730     MPM.addPass(ThinLTOBitcodeWriterPass(OutStream, nullptr));
731     MPM.run(*M, MAM);
732   } else {
733     std::unique_ptr<ModuleSummaryIndex> Index;
734     if (LTOInfo && LTOInfo->HasSummary) {
735       ProfileSummaryInfo PSI(*M);
736       Index = std::make_unique<ModuleSummaryIndex>(
737           buildModuleSummaryIndex(*M, nullptr, &PSI));
738     }
739     WriteBitcodeToFile(getModule(), OutStream,
740                        /*ShouldPreserveUseListOrder=*/true, Index.get());
741   }
742 }
743 
744 std::pair<std::unique_ptr<ReducerWorkItem>, bool>
745 llvm::parseReducerWorkItem(StringRef ToolName, StringRef Filename,
746                            LLVMContext &Ctxt,
747                            std::unique_ptr<TargetMachine> &TM, bool IsMIR) {
748   bool IsBitcode = false;
749   Triple TheTriple;
750 
751   auto MMM = std::make_unique<ReducerWorkItem>();
752 
753   if (IsMIR) {
754     initializeTargetInfo();
755 
756     auto FileOrErr = MemoryBuffer::getFileOrSTDIN(Filename, /*IsText=*/true);
757     if (std::error_code EC = FileOrErr.getError()) {
758       WithColor::error(errs(), ToolName) << EC.message() << '\n';
759       return {nullptr, false};
760     }
761 
762     std::unique_ptr<MIRParser> MParser =
763         createMIRParser(std::move(FileOrErr.get()), Ctxt);
764 
765     auto SetDataLayout = [&](StringRef DataLayoutTargetTriple,
766                              StringRef OldDLStr) -> std::optional<std::string> {
767       // NB: We always call createTargetMachineForTriple() even if an explicit
768       // DataLayout is already set in the module since we want to use this
769       // callback to setup the TargetMachine rather than doing it later.
770       std::string IRTargetTriple = DataLayoutTargetTriple.str();
771       if (!TargetTriple.empty())
772         IRTargetTriple = Triple::normalize(TargetTriple);
773       TheTriple = Triple(IRTargetTriple);
774       if (TheTriple.getTriple().empty())
775         TheTriple.setTriple(sys::getDefaultTargetTriple());
776       ExitOnError ExitOnErr(std::string(ToolName) + ": error: ");
777       TM = ExitOnErr(codegen::createTargetMachineForTriple(TheTriple.str()));
778 
779       return TM->createDataLayout().getStringRepresentation();
780     };
781 
782     std::unique_ptr<Module> M = MParser->parseIRModule(SetDataLayout);
783     LLVMTargetMachine *LLVMTM = static_cast<LLVMTargetMachine *>(TM.get());
784 
785     MMM->MMI = std::make_unique<MachineModuleInfo>(LLVMTM);
786     MParser->parseMachineFunctions(*M, *MMM->MMI);
787     MMM->M = std::move(M);
788   } else {
789     SMDiagnostic Err;
790     ErrorOr<std::unique_ptr<MemoryBuffer>> MB =
791         MemoryBuffer::getFileOrSTDIN(Filename);
792     if (std::error_code EC = MB.getError()) {
793       WithColor::error(errs(), ToolName)
794           << Filename << ": " << EC.message() << "\n";
795       return {nullptr, false};
796     }
797 
798     if (!isBitcode((const unsigned char *)(*MB)->getBufferStart(),
799                    (const unsigned char *)(*MB)->getBufferEnd())) {
800       std::unique_ptr<Module> Result = parseIR(**MB, Err, Ctxt);
801       if (!Result) {
802         Err.print(ToolName.data(), errs());
803         return {nullptr, false};
804       }
805       MMM->M = std::move(Result);
806     } else {
807       IsBitcode = true;
808       MMM->readBitcode(MemoryBufferRef(**MB), Ctxt, ToolName);
809 
810       if (MMM->LTOInfo->IsThinLTO && MMM->LTOInfo->EnableSplitLTOUnit)
811         initializeTargetInfo();
812     }
813   }
814   if (MMM->verify(&errs())) {
815     WithColor::error(errs(), ToolName)
816         << Filename << " - input module is broken!\n";
817     return {nullptr, false};
818   }
819   return {std::move(MMM), IsBitcode};
820 }
821