xref: /llvm-project/llvm/tools/llvm-reduce/ReducerWorkItem.cpp (revision 9a258664024d12a06ba8eb9344e270a9bb5f5d87) 
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/MachineJumpTableInfo.h"
23 #include "llvm/CodeGen/MachineModuleInfo.h"
24 #include "llvm/CodeGen/MachineRegisterInfo.h"
25 #include "llvm/CodeGen/PseudoSourceValueManager.h"
26 #include "llvm/CodeGen/TargetInstrInfo.h"
27 #include "llvm/IR/Constants.h"
28 #include "llvm/IR/Instructions.h"
29 #include "llvm/IR/ModuleSummaryIndex.h"
30 #include "llvm/IR/Operator.h"
31 #include "llvm/IR/Verifier.h"
32 #include "llvm/IRReader/IRReader.h"
33 #include "llvm/MC/TargetRegistry.h"
34 #include "llvm/Passes/PassBuilder.h"
35 #include "llvm/Support/MemoryBufferRef.h"
36 #include "llvm/Support/SourceMgr.h"
37 #include "llvm/Support/TargetSelect.h"
38 #include "llvm/Support/ToolOutputFile.h"
39 #include "llvm/Support/WithColor.h"
40 #include "llvm/Target/TargetMachine.h"
41 #include "llvm/TargetParser/Host.h"
42 #include "llvm/Transforms/IPO/ThinLTOBitcodeWriter.h"
43 #include "llvm/Transforms/Utils/Cloning.h"
44 #include <optional>
45 
46 using namespace llvm;
47 
48 ReducerWorkItem::ReducerWorkItem() = default;
49 ReducerWorkItem::~ReducerWorkItem() = default;
50 
51 extern cl::OptionCategory LLVMReduceOptions;
52 static cl::opt<std::string> TargetTriple("mtriple",
53                                          cl::desc("Set the target triple"),
54                                          cl::cat(LLVMReduceOptions));
55 
56 static cl::opt<bool> TmpFilesAsBitcode(
57     "write-tmp-files-as-bitcode",
58     cl::desc("Always write temporary files as bitcode instead of textual IR"),
59     cl::init(false), cl::cat(LLVMReduceOptions));
60 
61 static void cloneFrameInfo(
62     MachineFrameInfo &DstMFI, const MachineFrameInfo &SrcMFI,
63     const DenseMap<MachineBasicBlock *, MachineBasicBlock *> &Src2DstMBB) {
64   DstMFI.setFrameAddressIsTaken(SrcMFI.isFrameAddressTaken());
65   DstMFI.setReturnAddressIsTaken(SrcMFI.isReturnAddressTaken());
66   DstMFI.setHasStackMap(SrcMFI.hasStackMap());
67   DstMFI.setHasPatchPoint(SrcMFI.hasPatchPoint());
68   DstMFI.setUseLocalStackAllocationBlock(
69       SrcMFI.getUseLocalStackAllocationBlock());
70   DstMFI.setOffsetAdjustment(SrcMFI.getOffsetAdjustment());
71 
72   DstMFI.ensureMaxAlignment(SrcMFI.getMaxAlign());
73   assert(DstMFI.getMaxAlign() == SrcMFI.getMaxAlign() &&
74          "we need to set exact alignment");
75 
76   DstMFI.setAdjustsStack(SrcMFI.adjustsStack());
77   DstMFI.setHasCalls(SrcMFI.hasCalls());
78   DstMFI.setHasOpaqueSPAdjustment(SrcMFI.hasOpaqueSPAdjustment());
79   DstMFI.setHasCopyImplyingStackAdjustment(
80       SrcMFI.hasCopyImplyingStackAdjustment());
81   DstMFI.setHasVAStart(SrcMFI.hasVAStart());
82   DstMFI.setHasMustTailInVarArgFunc(SrcMFI.hasMustTailInVarArgFunc());
83   DstMFI.setHasTailCall(SrcMFI.hasTailCall());
84 
85   if (SrcMFI.isMaxCallFrameSizeComputed())
86     DstMFI.setMaxCallFrameSize(SrcMFI.getMaxCallFrameSize());
87 
88   DstMFI.setCVBytesOfCalleeSavedRegisters(
89       SrcMFI.getCVBytesOfCalleeSavedRegisters());
90 
91   if (MachineBasicBlock *SavePt = SrcMFI.getSavePoint())
92     DstMFI.setSavePoint(Src2DstMBB.find(SavePt)->second);
93   if (MachineBasicBlock *RestorePt = SrcMFI.getRestorePoint())
94     DstMFI.setRestorePoint(Src2DstMBB.find(RestorePt)->second);
95 
96 
97   auto CopyObjectProperties = [](MachineFrameInfo &DstMFI,
98                                  const MachineFrameInfo &SrcMFI, int FI) {
99     if (SrcMFI.isStatepointSpillSlotObjectIndex(FI))
100       DstMFI.markAsStatepointSpillSlotObjectIndex(FI);
101     DstMFI.setObjectSSPLayout(FI, SrcMFI.getObjectSSPLayout(FI));
102     DstMFI.setObjectZExt(FI, SrcMFI.isObjectZExt(FI));
103     DstMFI.setObjectSExt(FI, SrcMFI.isObjectSExt(FI));
104   };
105 
106   for (int i = 0, e = SrcMFI.getNumObjects() - SrcMFI.getNumFixedObjects();
107        i != e; ++i) {
108     int NewFI;
109 
110     assert(!SrcMFI.isFixedObjectIndex(i));
111     if (SrcMFI.isVariableSizedObjectIndex(i)) {
112       NewFI = DstMFI.CreateVariableSizedObject(SrcMFI.getObjectAlign(i),
113                                                SrcMFI.getObjectAllocation(i));
114     } else {
115       NewFI = DstMFI.CreateStackObject(
116           SrcMFI.getObjectSize(i), SrcMFI.getObjectAlign(i),
117           SrcMFI.isSpillSlotObjectIndex(i), SrcMFI.getObjectAllocation(i),
118           SrcMFI.getStackID(i));
119       DstMFI.setObjectOffset(NewFI, SrcMFI.getObjectOffset(i));
120     }
121 
122     CopyObjectProperties(DstMFI, SrcMFI, i);
123 
124     (void)NewFI;
125     assert(i == NewFI && "expected to keep stable frame index numbering");
126   }
127 
128   // Copy the fixed frame objects backwards to preserve frame index numbers,
129   // since CreateFixedObject uses front insertion.
130   for (int i = -1; i >= (int)-SrcMFI.getNumFixedObjects(); --i) {
131     assert(SrcMFI.isFixedObjectIndex(i));
132     int NewFI = DstMFI.CreateFixedObject(
133       SrcMFI.getObjectSize(i), SrcMFI.getObjectOffset(i),
134       SrcMFI.isImmutableObjectIndex(i), SrcMFI.isAliasedObjectIndex(i));
135     CopyObjectProperties(DstMFI, SrcMFI, i);
136 
137     (void)NewFI;
138     assert(i == NewFI && "expected to keep stable frame index numbering");
139   }
140 
141   for (unsigned I = 0, E = SrcMFI.getLocalFrameObjectCount(); I < E; ++I) {
142     auto LocalObject = SrcMFI.getLocalFrameObjectMap(I);
143     DstMFI.mapLocalFrameObject(LocalObject.first, LocalObject.second);
144   }
145 
146   DstMFI.setCalleeSavedInfo(SrcMFI.getCalleeSavedInfo());
147 
148   if (SrcMFI.hasStackProtectorIndex()) {
149     DstMFI.setStackProtectorIndex(SrcMFI.getStackProtectorIndex());
150   }
151 
152   // FIXME: Needs test, missing MIR serialization.
153   if (SrcMFI.hasFunctionContextIndex()) {
154     DstMFI.setFunctionContextIndex(SrcMFI.getFunctionContextIndex());
155   }
156 }
157 
158 static void cloneJumpTableInfo(
159     MachineFunction &DstMF, const MachineJumpTableInfo &SrcJTI,
160     const DenseMap<MachineBasicBlock *, MachineBasicBlock *> &Src2DstMBB) {
161 
162   auto *DstJTI = DstMF.getOrCreateJumpTableInfo(SrcJTI.getEntryKind());
163 
164   std::vector<MachineBasicBlock *> DstBBs;
165 
166   for (const MachineJumpTableEntry &Entry : SrcJTI.getJumpTables()) {
167     for (MachineBasicBlock *X : Entry.MBBs)
168       DstBBs.push_back(Src2DstMBB.find(X)->second);
169 
170     DstJTI->createJumpTableIndex(DstBBs);
171     DstBBs.clear();
172   }
173 }
174 
175 static void cloneMemOperands(MachineInstr &DstMI, MachineInstr &SrcMI,
176                              MachineFunction &SrcMF, MachineFunction &DstMF) {
177   // The new MachineMemOperands should be owned by the new function's
178   // Allocator.
179   PseudoSourceValueManager &PSVMgr = DstMF.getPSVManager();
180 
181   // We also need to remap the PseudoSourceValues from the new function's
182   // PseudoSourceValueManager.
183   SmallVector<MachineMemOperand *, 2> NewMMOs;
184   for (MachineMemOperand *OldMMO : SrcMI.memoperands()) {
185     MachinePointerInfo NewPtrInfo(OldMMO->getPointerInfo());
186     if (const PseudoSourceValue *PSV =
187             dyn_cast_if_present<const PseudoSourceValue *>(NewPtrInfo.V)) {
188       switch (PSV->kind()) {
189       case PseudoSourceValue::Stack:
190         NewPtrInfo.V = PSVMgr.getStack();
191         break;
192       case PseudoSourceValue::GOT:
193         NewPtrInfo.V = PSVMgr.getGOT();
194         break;
195       case PseudoSourceValue::JumpTable:
196         NewPtrInfo.V = PSVMgr.getJumpTable();
197         break;
198       case PseudoSourceValue::ConstantPool:
199         NewPtrInfo.V = PSVMgr.getConstantPool();
200         break;
201       case PseudoSourceValue::FixedStack:
202         NewPtrInfo.V = PSVMgr.getFixedStack(
203             cast<FixedStackPseudoSourceValue>(PSV)->getFrameIndex());
204         break;
205       case PseudoSourceValue::GlobalValueCallEntry:
206         NewPtrInfo.V = PSVMgr.getGlobalValueCallEntry(
207             cast<GlobalValuePseudoSourceValue>(PSV)->getValue());
208         break;
209       case PseudoSourceValue::ExternalSymbolCallEntry:
210         NewPtrInfo.V = PSVMgr.getExternalSymbolCallEntry(
211             cast<ExternalSymbolPseudoSourceValue>(PSV)->getSymbol());
212         break;
213       case PseudoSourceValue::TargetCustom:
214       default:
215         // FIXME: We have no generic interface for allocating custom PSVs.
216         report_fatal_error("Cloning TargetCustom PSV not handled");
217       }
218     }
219 
220     MachineMemOperand *NewMMO = DstMF.getMachineMemOperand(
221         NewPtrInfo, OldMMO->getFlags(), OldMMO->getMemoryType(),
222         OldMMO->getBaseAlign(), OldMMO->getAAInfo(), OldMMO->getRanges(),
223         OldMMO->getSyncScopeID(), OldMMO->getSuccessOrdering(),
224         OldMMO->getFailureOrdering());
225     NewMMOs.push_back(NewMMO);
226   }
227 
228   DstMI.setMemRefs(DstMF, NewMMOs);
229 }
230 
231 static std::unique_ptr<MachineFunction> cloneMF(MachineFunction *SrcMF,
232                                                 MachineModuleInfo &DestMMI) {
233   auto DstMF = std::make_unique<MachineFunction>(
234       SrcMF->getFunction(), SrcMF->getTarget(), SrcMF->getSubtarget(),
235       SrcMF->getFunctionNumber(), DestMMI);
236   DenseMap<MachineBasicBlock *, MachineBasicBlock *> Src2DstMBB;
237 
238   auto *SrcMRI = &SrcMF->getRegInfo();
239   auto *DstMRI = &DstMF->getRegInfo();
240 
241   // Clone blocks.
242   for (MachineBasicBlock &SrcMBB : *SrcMF) {
243     MachineBasicBlock *DstMBB =
244         DstMF->CreateMachineBasicBlock(SrcMBB.getBasicBlock());
245     Src2DstMBB[&SrcMBB] = DstMBB;
246 
247     DstMBB->setCallFrameSize(SrcMBB.getCallFrameSize());
248 
249     if (SrcMBB.isIRBlockAddressTaken())
250       DstMBB->setAddressTakenIRBlock(SrcMBB.getAddressTakenIRBlock());
251     if (SrcMBB.isMachineBlockAddressTaken())
252       DstMBB->setMachineBlockAddressTaken();
253 
254     // FIXME: This is not serialized
255     if (SrcMBB.hasLabelMustBeEmitted())
256       DstMBB->setLabelMustBeEmitted();
257 
258     DstMBB->setAlignment(SrcMBB.getAlignment());
259 
260     // FIXME: This is not serialized
261     DstMBB->setMaxBytesForAlignment(SrcMBB.getMaxBytesForAlignment());
262 
263     DstMBB->setIsEHPad(SrcMBB.isEHPad());
264     DstMBB->setIsEHScopeEntry(SrcMBB.isEHScopeEntry());
265     DstMBB->setIsEHCatchretTarget(SrcMBB.isEHCatchretTarget());
266     DstMBB->setIsEHFuncletEntry(SrcMBB.isEHFuncletEntry());
267 
268     // FIXME: These are not serialized
269     DstMBB->setIsCleanupFuncletEntry(SrcMBB.isCleanupFuncletEntry());
270     DstMBB->setIsBeginSection(SrcMBB.isBeginSection());
271     DstMBB->setIsEndSection(SrcMBB.isEndSection());
272 
273     DstMBB->setSectionID(SrcMBB.getSectionID());
274     DstMBB->setIsInlineAsmBrIndirectTarget(
275         SrcMBB.isInlineAsmBrIndirectTarget());
276 
277     // FIXME: This is not serialized
278     if (std::optional<uint64_t> Weight = SrcMBB.getIrrLoopHeaderWeight())
279       DstMBB->setIrrLoopHeaderWeight(*Weight);
280   }
281 
282   const MachineFrameInfo &SrcMFI = SrcMF->getFrameInfo();
283   MachineFrameInfo &DstMFI = DstMF->getFrameInfo();
284 
285   // Copy stack objects and other info
286   cloneFrameInfo(DstMFI, SrcMFI, Src2DstMBB);
287 
288   if (MachineJumpTableInfo *SrcJTI = SrcMF->getJumpTableInfo()) {
289     cloneJumpTableInfo(*DstMF, *SrcJTI, Src2DstMBB);
290   }
291 
292   // Remap the debug info frame index references.
293   DstMF->VariableDbgInfos = SrcMF->VariableDbgInfos;
294 
295   // Clone virtual registers
296   for (unsigned I = 0, E = SrcMRI->getNumVirtRegs(); I != E; ++I) {
297     Register Reg = Register::index2VirtReg(I);
298     Register NewReg = DstMRI->createIncompleteVirtualRegister(
299       SrcMRI->getVRegName(Reg));
300     assert(NewReg == Reg && "expected to preserve virtreg number");
301 
302     DstMRI->setRegClassOrRegBank(NewReg, SrcMRI->getRegClassOrRegBank(Reg));
303 
304     LLT RegTy = SrcMRI->getType(Reg);
305     if (RegTy.isValid())
306       DstMRI->setType(NewReg, RegTy);
307 
308     // Copy register allocation hints.
309     const auto &Hints = SrcMRI->getRegAllocationHints(Reg);
310     for (Register PrefReg : Hints.second)
311       DstMRI->addRegAllocationHint(NewReg, PrefReg);
312   }
313 
314   const TargetSubtargetInfo &STI = DstMF->getSubtarget();
315   const TargetInstrInfo *TII = STI.getInstrInfo();
316   const TargetRegisterInfo *TRI = STI.getRegisterInfo();
317 
318   // Link blocks.
319   for (auto &SrcMBB : *SrcMF) {
320     auto *DstMBB = Src2DstMBB[&SrcMBB];
321     DstMF->push_back(DstMBB);
322 
323     for (auto It = SrcMBB.succ_begin(), IterEnd = SrcMBB.succ_end();
324          It != IterEnd; ++It) {
325       auto *SrcSuccMBB = *It;
326       auto *DstSuccMBB = Src2DstMBB[SrcSuccMBB];
327       DstMBB->addSuccessor(DstSuccMBB, SrcMBB.getSuccProbability(It));
328     }
329 
330     for (auto &LI : SrcMBB.liveins_dbg())
331       DstMBB->addLiveIn(LI);
332 
333     // Make sure MRI knows about registers clobbered by unwinder.
334     if (DstMBB->isEHPad()) {
335       if (auto *RegMask = TRI->getCustomEHPadPreservedMask(*DstMF))
336         DstMRI->addPhysRegsUsedFromRegMask(RegMask);
337     }
338   }
339 
340   DenseSet<const uint32_t *> ConstRegisterMasks;
341 
342   // Track predefined/named regmasks which we ignore.
343   for (const uint32_t *Mask : TRI->getRegMasks())
344     ConstRegisterMasks.insert(Mask);
345 
346   // Clone instructions.
347   for (auto &SrcMBB : *SrcMF) {
348     auto *DstMBB = Src2DstMBB[&SrcMBB];
349     for (auto &SrcMI : SrcMBB) {
350       const auto &MCID = TII->get(SrcMI.getOpcode());
351       auto *DstMI = DstMF->CreateMachineInstr(MCID, SrcMI.getDebugLoc(),
352                                               /*NoImplicit=*/true);
353       DstMI->setFlags(SrcMI.getFlags());
354       DstMI->setAsmPrinterFlag(SrcMI.getAsmPrinterFlags());
355 
356       DstMBB->push_back(DstMI);
357       for (auto &SrcMO : SrcMI.operands()) {
358         MachineOperand DstMO(SrcMO);
359         DstMO.clearParent();
360 
361         // Update MBB.
362         if (DstMO.isMBB())
363           DstMO.setMBB(Src2DstMBB[DstMO.getMBB()]);
364         else if (DstMO.isRegMask()) {
365           DstMRI->addPhysRegsUsedFromRegMask(DstMO.getRegMask());
366 
367           if (!ConstRegisterMasks.count(DstMO.getRegMask())) {
368             uint32_t *DstMask = DstMF->allocateRegMask();
369             std::memcpy(DstMask, SrcMO.getRegMask(),
370                         sizeof(*DstMask) *
371                             MachineOperand::getRegMaskSize(TRI->getNumRegs()));
372             DstMO.setRegMask(DstMask);
373           }
374         }
375 
376         DstMI->addOperand(DstMO);
377       }
378 
379       cloneMemOperands(*DstMI, SrcMI, *SrcMF, *DstMF);
380     }
381   }
382 
383   DstMF->setAlignment(SrcMF->getAlignment());
384   DstMF->setExposesReturnsTwice(SrcMF->exposesReturnsTwice());
385   DstMF->setHasInlineAsm(SrcMF->hasInlineAsm());
386   DstMF->setHasWinCFI(SrcMF->hasWinCFI());
387 
388   DstMF->getProperties().reset().set(SrcMF->getProperties());
389 
390   if (!SrcMF->getFrameInstructions().empty() ||
391       !SrcMF->getLongjmpTargets().empty() ||
392       !SrcMF->getCatchretTargets().empty())
393     report_fatal_error("cloning not implemented for machine function property");
394 
395   DstMF->setCallsEHReturn(SrcMF->callsEHReturn());
396   DstMF->setCallsUnwindInit(SrcMF->callsUnwindInit());
397   DstMF->setHasEHCatchret(SrcMF->hasEHCatchret());
398   DstMF->setHasEHScopes(SrcMF->hasEHScopes());
399   DstMF->setHasEHFunclets(SrcMF->hasEHFunclets());
400   DstMF->setIsOutlined(SrcMF->isOutlined());
401 
402   if (!SrcMF->getLandingPads().empty() ||
403       !SrcMF->getCodeViewAnnotations().empty() ||
404       !SrcMF->getTypeInfos().empty() ||
405       !SrcMF->getFilterIds().empty() ||
406       SrcMF->hasAnyWasmLandingPadIndex() ||
407       SrcMF->hasAnyCallSiteLandingPad() ||
408       SrcMF->hasAnyCallSiteLabel() ||
409       !SrcMF->getCallSitesInfo().empty())
410     report_fatal_error("cloning not implemented for machine function property");
411 
412   DstMF->setDebugInstrNumberingCount(SrcMF->DebugInstrNumberingCount);
413 
414   if (!DstMF->cloneInfoFrom(*SrcMF, Src2DstMBB))
415     report_fatal_error("target does not implement MachineFunctionInfo cloning");
416 
417   DstMRI->freezeReservedRegs();
418 
419   DstMF->verify(nullptr, "", /*AbortOnError=*/true);
420   return DstMF;
421 }
422 
423 static void initializeTargetInfo() {
424   InitializeAllTargets();
425   InitializeAllTargetMCs();
426   InitializeAllAsmPrinters();
427   InitializeAllAsmParsers();
428 }
429 
430 void ReducerWorkItem::print(raw_ostream &ROS, void *p) const {
431   if (MMI) {
432     printMIR(ROS, *M);
433     for (Function &F : *M) {
434       if (auto *MF = MMI->getMachineFunction(F))
435         printMIR(ROS, *MMI, *MF);
436     }
437   } else {
438     M->print(ROS, /*AssemblyAnnotationWriter=*/nullptr,
439              /*ShouldPreserveUseListOrder=*/true);
440   }
441 }
442 
443 bool ReducerWorkItem::verify(raw_fd_ostream *OS) const {
444   if (verifyModule(*M, OS))
445     return true;
446 
447   if (!MMI)
448     return false;
449 
450   for (const Function &F : getModule()) {
451     if (const MachineFunction *MF = MMI->getMachineFunction(F)) {
452       if (!MF->verify(nullptr, "", /*AbortOnError=*/false))
453         return true;
454     }
455   }
456 
457   return false;
458 }
459 
460 bool ReducerWorkItem::isReduced(const TestRunner &Test) const {
461   const bool UseBitcode = Test.inputIsBitcode() || TmpFilesAsBitcode;
462 
463   SmallString<128> CurrentFilepath;
464 
465   // Write ReducerWorkItem to tmp file
466   int FD;
467   std::error_code EC = sys::fs::createTemporaryFile(
468       "llvm-reduce", isMIR() ? "mir" : (UseBitcode ? "bc" : "ll"), FD,
469       CurrentFilepath,
470       UseBitcode && !isMIR() ? sys::fs::OF_None : sys::fs::OF_Text);
471   if (EC) {
472     WithColor::error(errs(), Test.getToolName())
473         << "error making unique filename: " << EC.message() << '\n';
474     exit(1);
475   }
476 
477   ToolOutputFile Out(CurrentFilepath, FD);
478 
479   writeOutput(Out.os(), UseBitcode);
480 
481   Out.os().close();
482   if (Out.os().has_error()) {
483     WithColor::error(errs(), Test.getToolName())
484         << "error emitting bitcode to file '" << CurrentFilepath
485         << "': " << Out.os().error().message() << '\n';
486     exit(1);
487   }
488 
489   // Current Chunks aren't interesting
490   return Test.run(CurrentFilepath);
491 }
492 
493 std::unique_ptr<ReducerWorkItem>
494 ReducerWorkItem::clone(const TargetMachine *TM) const {
495   auto CloneMMM = std::make_unique<ReducerWorkItem>();
496   if (TM) {
497     // We're assuming the Module IR contents are always unchanged by MIR
498     // reductions, and can share it as a constant.
499     CloneMMM->M = M;
500 
501     // MachineModuleInfo contains a lot of other state used during codegen which
502     // we won't be using here, but we should be able to ignore it (although this
503     // is pretty ugly).
504     const LLVMTargetMachine *LLVMTM =
505         static_cast<const LLVMTargetMachine *>(TM);
506     CloneMMM->MMI = std::make_unique<MachineModuleInfo>(LLVMTM);
507 
508     for (const Function &F : getModule()) {
509       if (auto *MF = MMI->getMachineFunction(F))
510         CloneMMM->MMI->insertFunction(F, cloneMF(MF, *CloneMMM->MMI));
511     }
512   } else {
513     CloneMMM->M = CloneModule(*M);
514   }
515   return CloneMMM;
516 }
517 
518 /// Try to produce some number that indicates a function is getting smaller /
519 /// simpler.
520 static uint64_t computeMIRComplexityScoreImpl(const MachineFunction &MF) {
521   uint64_t Score = 0;
522   const MachineFrameInfo &MFI = MF.getFrameInfo();
523 
524   // Add for stack objects
525   Score += MFI.getNumObjects();
526 
527   // Add in the block count.
528   Score += 2 * MF.size();
529 
530   const MachineRegisterInfo &MRI = MF.getRegInfo();
531   for (unsigned I = 0, E = MRI.getNumVirtRegs(); I != E; ++I) {
532     Register Reg = Register::index2VirtReg(I);
533     Score += MRI.getRegAllocationHints(Reg).second.size();
534   }
535 
536   for (const MachineBasicBlock &MBB : MF) {
537     for (const MachineInstr &MI : MBB) {
538       const unsigned Opc = MI.getOpcode();
539 
540       // Reductions may want or need to introduce implicit_defs, so don't count
541       // them.
542       // TODO: These probably should count in some way.
543       if (Opc == TargetOpcode::IMPLICIT_DEF ||
544           Opc == TargetOpcode::G_IMPLICIT_DEF)
545         continue;
546 
547       // Each instruction adds to the score
548       Score += 4;
549 
550       if (Opc == TargetOpcode::PHI || Opc == TargetOpcode::G_PHI ||
551           Opc == TargetOpcode::INLINEASM || Opc == TargetOpcode::INLINEASM_BR)
552         ++Score;
553 
554       if (MI.getFlags() != 0)
555         ++Score;
556 
557       // Increase weight for more operands.
558       for (const MachineOperand &MO : MI.operands()) {
559         ++Score;
560 
561         // Treat registers as more complex.
562         if (MO.isReg()) {
563           ++Score;
564 
565           // And subregisters as even more complex.
566           if (MO.getSubReg()) {
567             ++Score;
568             if (MO.isDef())
569               ++Score;
570           }
571         } else if (MO.isRegMask())
572           ++Score;
573       }
574     }
575   }
576 
577   return Score;
578 }
579 
580 uint64_t ReducerWorkItem::computeMIRComplexityScore() const {
581   uint64_t Score = 0;
582 
583   for (const Function &F : getModule()) {
584     if (auto *MF = MMI->getMachineFunction(F))
585       Score += computeMIRComplexityScoreImpl(*MF);
586   }
587 
588   return Score;
589 }
590 
591 // FIXME: ReduceOperandsSkip has similar function, except it uses larger numbers
592 // for more reduced.
593 static unsigned classifyReductivePower(const Value *V) {
594   if (auto *C = dyn_cast<ConstantData>(V)) {
595     if (C->isNullValue())
596       return 0;
597     if (C->isOneValue())
598       return 1;
599     if (isa<UndefValue>(V))
600       return 2;
601     return 3;
602   }
603 
604   if (isa<GlobalValue>(V))
605     return 4;
606 
607   // TODO: Account for expression size
608   if (isa<ConstantExpr>(V))
609     return 5;
610 
611   if (isa<Constant>(V))
612     return 1;
613 
614   if (isa<Argument>(V))
615     return 6;
616 
617   if (isa<Instruction>(V))
618     return 7;
619 
620   return 0;
621 }
622 
623 // TODO: Additional flags and attributes may be complexity reducing. If we start
624 // adding flags and attributes, they could have negative cost.
625 static uint64_t computeIRComplexityScoreImpl(const Function &F) {
626   uint64_t Score = 1; // Count the function itself
627   SmallVector<std::pair<unsigned, MDNode *>> MDs;
628 
629   AttributeList Attrs = F.getAttributes();
630   for (AttributeSet AttrSet : Attrs)
631     Score += AttrSet.getNumAttributes();
632 
633   for (const BasicBlock &BB : F) {
634     ++Score;
635 
636     for (const Instruction &I : BB) {
637       ++Score;
638 
639       if (const auto *OverflowOp = dyn_cast<OverflowingBinaryOperator>(&I)) {
640         if (OverflowOp->hasNoUnsignedWrap())
641           ++Score;
642         if (OverflowOp->hasNoSignedWrap())
643           ++Score;
644       } else if (const auto *GEP = dyn_cast<GEPOperator>(&I)) {
645         if (GEP->isInBounds())
646           ++Score;
647       } else if (const auto *ExactOp = dyn_cast<PossiblyExactOperator>(&I)) {
648         if (ExactOp->isExact())
649           ++Score;
650       } else if (const auto *FPOp = dyn_cast<FPMathOperator>(&I)) {
651         FastMathFlags FMF = FPOp->getFastMathFlags();
652         if (FMF.allowReassoc())
653           ++Score;
654         if (FMF.noNaNs())
655           ++Score;
656         if (FMF.noInfs())
657           ++Score;
658         if (FMF.noSignedZeros())
659           ++Score;
660         if (FMF.allowReciprocal())
661           ++Score;
662         if (FMF.allowContract())
663           ++Score;
664         if (FMF.approxFunc())
665           ++Score;
666       }
667 
668       for (const Value *Operand : I.operands()) {
669         ++Score;
670         Score += classifyReductivePower(Operand);
671       }
672 
673       I.getAllMetadata(MDs);
674       Score += MDs.size();
675       MDs.clear();
676     }
677   }
678 
679   return Score;
680 }
681 
682 uint64_t ReducerWorkItem::computeIRComplexityScore() const {
683   uint64_t Score = 0;
684 
685   const Module &M = getModule();
686   Score += M.named_metadata_size();
687 
688   SmallVector<std::pair<unsigned, MDNode *>, 32> GlobalMetadata;
689   for (const GlobalVariable &GV : M.globals()) {
690     ++Score;
691 
692     if (GV.hasInitializer())
693       Score += classifyReductivePower(GV.getInitializer());
694 
695     // TODO: Account for linkage?
696 
697     GV.getAllMetadata(GlobalMetadata);
698     Score += GlobalMetadata.size();
699     GlobalMetadata.clear();
700   }
701 
702   for (const GlobalAlias &GA : M.aliases())
703     Score += classifyReductivePower(GA.getAliasee());
704 
705   for (const GlobalIFunc &GI : M.ifuncs())
706     Score += classifyReductivePower(GI.getResolver());
707 
708   for (const Function &F : M)
709     Score += computeIRComplexityScoreImpl(F);
710 
711   return Score;
712 }
713 
714 void ReducerWorkItem::writeOutput(raw_ostream &OS, bool EmitBitcode) const {
715   // Requesting bitcode emission with mir is nonsense, so just ignore it.
716   if (EmitBitcode && !isMIR())
717     writeBitcode(OS);
718   else
719     print(OS, /*AnnotationWriter=*/nullptr);
720 }
721 
722 void ReducerWorkItem::readBitcode(MemoryBufferRef Data, LLVMContext &Ctx,
723                                   StringRef ToolName) {
724   Expected<BitcodeFileContents> IF = llvm::getBitcodeFileContents(Data);
725   if (!IF) {
726     WithColor::error(errs(), ToolName) << IF.takeError();
727     exit(1);
728   }
729   BitcodeModule BM = IF->Mods[0];
730   Expected<BitcodeLTOInfo> LI = BM.getLTOInfo();
731   Expected<std::unique_ptr<Module>> MOrErr = BM.parseModule(Ctx);
732   if (!LI || !MOrErr) {
733     WithColor::error(errs(), ToolName) << IF.takeError();
734     exit(1);
735   }
736   LTOInfo = std::make_unique<BitcodeLTOInfo>(*LI);
737   M = std::move(MOrErr.get());
738 }
739 
740 void ReducerWorkItem::writeBitcode(raw_ostream &OutStream) const {
741   if (LTOInfo && LTOInfo->IsThinLTO && LTOInfo->EnableSplitLTOUnit) {
742     PassBuilder PB;
743     LoopAnalysisManager LAM;
744     FunctionAnalysisManager FAM;
745     CGSCCAnalysisManager CGAM;
746     ModuleAnalysisManager MAM;
747     PB.registerModuleAnalyses(MAM);
748     PB.registerCGSCCAnalyses(CGAM);
749     PB.registerFunctionAnalyses(FAM);
750     PB.registerLoopAnalyses(LAM);
751     PB.crossRegisterProxies(LAM, FAM, CGAM, MAM);
752     ModulePassManager MPM;
753     MPM.addPass(ThinLTOBitcodeWriterPass(OutStream, nullptr));
754     MPM.run(*M, MAM);
755   } else {
756     std::unique_ptr<ModuleSummaryIndex> Index;
757     if (LTOInfo && LTOInfo->HasSummary) {
758       ProfileSummaryInfo PSI(*M);
759       Index = std::make_unique<ModuleSummaryIndex>(
760           buildModuleSummaryIndex(*M, nullptr, &PSI));
761     }
762     WriteBitcodeToFile(getModule(), OutStream,
763                        /*ShouldPreserveUseListOrder=*/true, Index.get());
764   }
765 }
766 
767 std::pair<std::unique_ptr<ReducerWorkItem>, bool>
768 llvm::parseReducerWorkItem(StringRef ToolName, StringRef Filename,
769                            LLVMContext &Ctxt,
770                            std::unique_ptr<TargetMachine> &TM, bool IsMIR) {
771   bool IsBitcode = false;
772   Triple TheTriple;
773 
774   auto MMM = std::make_unique<ReducerWorkItem>();
775 
776   if (IsMIR) {
777     initializeTargetInfo();
778 
779     auto FileOrErr = MemoryBuffer::getFileOrSTDIN(Filename, /*IsText=*/true);
780     if (std::error_code EC = FileOrErr.getError()) {
781       WithColor::error(errs(), ToolName) << EC.message() << '\n';
782       return {nullptr, false};
783     }
784 
785     std::unique_ptr<MIRParser> MParser =
786         createMIRParser(std::move(FileOrErr.get()), Ctxt);
787 
788     auto SetDataLayout = [&](StringRef DataLayoutTargetTriple,
789                              StringRef OldDLStr) -> std::optional<std::string> {
790       // NB: We always call createTargetMachineForTriple() even if an explicit
791       // DataLayout is already set in the module since we want to use this
792       // callback to setup the TargetMachine rather than doing it later.
793       std::string IRTargetTriple = DataLayoutTargetTriple.str();
794       if (!TargetTriple.empty())
795         IRTargetTriple = Triple::normalize(TargetTriple);
796       TheTriple = Triple(IRTargetTriple);
797       if (TheTriple.getTriple().empty())
798         TheTriple.setTriple(sys::getDefaultTargetTriple());
799       ExitOnError ExitOnErr(std::string(ToolName) + ": error: ");
800       TM = ExitOnErr(codegen::createTargetMachineForTriple(TheTriple.str()));
801 
802       return TM->createDataLayout().getStringRepresentation();
803     };
804 
805     std::unique_ptr<Module> M = MParser->parseIRModule(SetDataLayout);
806     LLVMTargetMachine *LLVMTM = static_cast<LLVMTargetMachine *>(TM.get());
807 
808     MMM->MMI = std::make_unique<MachineModuleInfo>(LLVMTM);
809     MParser->parseMachineFunctions(*M, *MMM->MMI);
810     MMM->M = std::move(M);
811   } else {
812     SMDiagnostic Err;
813     ErrorOr<std::unique_ptr<MemoryBuffer>> MB =
814         MemoryBuffer::getFileOrSTDIN(Filename);
815     if (std::error_code EC = MB.getError()) {
816       WithColor::error(errs(), ToolName)
817           << Filename << ": " << EC.message() << "\n";
818       return {nullptr, false};
819     }
820 
821     if (!isBitcode((const unsigned char *)(*MB)->getBufferStart(),
822                    (const unsigned char *)(*MB)->getBufferEnd())) {
823       std::unique_ptr<Module> Result = parseIR(**MB, Err, Ctxt);
824       if (!Result) {
825         Err.print(ToolName.data(), errs());
826         return {nullptr, false};
827       }
828       MMM->M = std::move(Result);
829     } else {
830       IsBitcode = true;
831       MMM->readBitcode(MemoryBufferRef(**MB), Ctxt, ToolName);
832 
833       if (MMM->LTOInfo->IsThinLTO && MMM->LTOInfo->EnableSplitLTOUnit)
834         initializeTargetInfo();
835     }
836   }
837   if (MMM->verify(&errs())) {
838     WithColor::error(errs(), ToolName)
839         << Filename << " - input module is broken!\n";
840     return {nullptr, false};
841   }
842   return {std::move(MMM), IsBitcode};
843 }
844