lib/CodeGen/MachineModuleInfo.cpp

   1 //===-- llvm/CodeGen/MachineModuleInfo.cpp ----------------------*- C++ -*-===//
   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 "llvm/CodeGen/MachineModuleInfo.h"
  10 #include "llvm/ADT/ArrayRef.h"
  11 #include "llvm/ADT/DenseMap.h"
  12 #include "llvm/ADT/PostOrderIterator.h"
  13 #include "llvm/ADT/StringRef.h"
  14 #include "llvm/ADT/TinyPtrVector.h"
  15 #include "llvm/CodeGen/MachineFunction.h"
  16 #include "llvm/CodeGen/Passes.h"
  17 #include "llvm/IR/BasicBlock.h"
  18 #include "llvm/IR/DerivedTypes.h"
  19 #include "llvm/IR/Instructions.h"
  20 #include "llvm/IR/Module.h"
  21 #include "llvm/IR/Value.h"
  22 #include "llvm/IR/ValueHandle.h"
  23 #include "llvm/MC/MCContext.h"
  24 #include "llvm/MC/MCSymbol.h"
  25 #include "llvm/Pass.h"
  26 #include "llvm/Support/Casting.h"
  27 #include "llvm/Support/ErrorHandling.h"
  28 #include "llvm/Target/TargetLoweringObjectFile.h"
  29 #include "llvm/Target/TargetMachine.h"
  30 #include <algorithm>
  31 #include <cassert>
  32 #include <memory>
  33 #include <utility>
  34 #include <vector>
  35
  36 using namespace llvm;
  37 using namespace llvm::dwarf;
  38
  39 // Out of line virtual method.
  40 MachineModuleInfoImpl::~MachineModuleInfoImpl() = default;
  41
  42 namespace llvm {
  43
  44 class MMIAddrLabelMapCallbackPtr final : CallbackVH {
  45   MMIAddrLabelMap *Map = nullptr;
  46
  47 public:
  48   MMIAddrLabelMapCallbackPtr() = default;
  49   MMIAddrLabelMapCallbackPtr(Value *V) : CallbackVH(V) {}
  50
  51   void setPtr(BasicBlock *BB) {
  52     ValueHandleBase::operator=(BB);
  53   }
  54
  55   void setMap(MMIAddrLabelMap *map) { Map = map; }
  56
  57   void deleted() override;
  58   void allUsesReplacedWith(Value *V2) override;
  59 };
  60
  61 class MMIAddrLabelMap {
  62   MCContext &Context;
  63   struct AddrLabelSymEntry {
  64     /// The symbols for the label.
  65     TinyPtrVector<MCSymbol *> Symbols;
  66
  67     Function *Fn;   // The containing function of the BasicBlock.
  68     unsigned Index; // The index in BBCallbacks for the BasicBlock.
  69   };
  70
  71   DenseMap<AssertingVH<BasicBlock>, AddrLabelSymEntry> AddrLabelSymbols;
  72
  73   /// Callbacks for the BasicBlock's that we have entries for.  We use this so
  74   /// we get notified if a block is deleted or RAUWd.
  75   std::vector<MMIAddrLabelMapCallbackPtr> BBCallbacks;
  76
  77   /// This is a per-function list of symbols whose corresponding BasicBlock got
  78   /// deleted.  These symbols need to be emitted at some point in the file, so
  79   /// AsmPrinter emits them after the function body.
  80   DenseMap<AssertingVH<Function>, std::vector<MCSymbol*>>
  81     DeletedAddrLabelsNeedingEmission;
  82
  83 public:
  84   MMIAddrLabelMap(MCContext &context) : Context(context) {}
  85
  86   ~MMIAddrLabelMap() {
  87     assert(DeletedAddrLabelsNeedingEmission.empty() &&
  88            "Some labels for deleted blocks never got emitted");
  89   }
  90
  91   ArrayRef<MCSymbol *> getAddrLabelSymbolToEmit(BasicBlock *BB);
  92
  93   void takeDeletedSymbolsForFunction(Function *F,
  94                                      std::vector<MCSymbol*> &Result);
  95
  96   void UpdateForDeletedBlock(BasicBlock *BB);
  97   void UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New);
  98 };
  99
 100 } // end namespace llvm
 101
 102 ArrayRef<MCSymbol *> MMIAddrLabelMap::getAddrLabelSymbolToEmit(BasicBlock *BB) {
 103   assert(BB->hasAddressTaken() &&
 104          "Shouldn't get label for block without address taken");
 105   AddrLabelSymEntry &Entry = AddrLabelSymbols[BB];
 106
 107   // If we already had an entry for this block, just return it.
 108   if (!Entry.Symbols.empty()) {
 109     assert(BB->getParent() == Entry.Fn && "Parent changed");
 110     return Entry.Symbols;
 111   }
 112
 113   // Otherwise, this is a new entry, create a new symbol for it and add an
 114   // entry to BBCallbacks so we can be notified if the BB is deleted or RAUWd.
 115   BBCallbacks.emplace_back(BB);
 116   BBCallbacks.back().setMap(this);
 117   Entry.Index = BBCallbacks.size() - 1;
 118   Entry.Fn = BB->getParent();
 119   Entry.Symbols.push_back(Context.createTempSymbol(!BB->hasAddressTaken()));
 120   return Entry.Symbols;
 121 }
 122
 123 /// If we have any deleted symbols for F, return them.
 124 void MMIAddrLabelMap::
 125 takeDeletedSymbolsForFunction(Function *F, std::vector<MCSymbol*> &Result) {
 126   DenseMap<AssertingVH<Function>, std::vector<MCSymbol*>>::iterator I =
 127     DeletedAddrLabelsNeedingEmission.find(F);
 128
 129   // If there are no entries for the function, just return.
 130   if (I == DeletedAddrLabelsNeedingEmission.end()) return;
 131
 132   // Otherwise, take the list.
 133   std::swap(Result, I->second);
 134   DeletedAddrLabelsNeedingEmission.erase(I);
 135 }
 136
 137 void MMIAddrLabelMap::UpdateForDeletedBlock(BasicBlock *BB) {
 138   // If the block got deleted, there is no need for the symbol.  If the symbol
 139   // was already emitted, we can just forget about it, otherwise we need to
 140   // queue it up for later emission when the function is output.
 141   AddrLabelSymEntry Entry = std::move(AddrLabelSymbols[BB]);
 142   AddrLabelSymbols.erase(BB);
 143   assert(!Entry.Symbols.empty() && "Didn't have a symbol, why a callback?");
 144   BBCallbacks[Entry.Index] = nullptr;  // Clear the callback.
 145
 146   assert((BB->getParent() == nullptr || BB->getParent() == Entry.Fn) &&
 147          "Block/parent mismatch");
 148
 149   for (MCSymbol *Sym : Entry.Symbols) {
 150     if (Sym->isDefined())
 151       return;
 152
 153     // If the block is not yet defined, we need to emit it at the end of the
 154     // function.  Add the symbol to the DeletedAddrLabelsNeedingEmission list
 155     // for the containing Function.  Since the block is being deleted, its
 156     // parent may already be removed, we have to get the function from 'Entry'.
 157     DeletedAddrLabelsNeedingEmission[Entry.Fn].push_back(Sym);
 158   }
 159 }
 160
 161 void MMIAddrLabelMap::UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New) {
 162   // Get the entry for the RAUW'd block and remove it from our map.
 163   AddrLabelSymEntry OldEntry = std::move(AddrLabelSymbols[Old]);
 164   AddrLabelSymbols.erase(Old);
 165   assert(!OldEntry.Symbols.empty() && "Didn't have a symbol, why a callback?");
 166
 167   AddrLabelSymEntry &NewEntry = AddrLabelSymbols[New];
 168
 169   // If New is not address taken, just move our symbol over to it.
 170   if (NewEntry.Symbols.empty()) {
 171     BBCallbacks[OldEntry.Index].setPtr(New);    // Update the callback.
 172     NewEntry = std::move(OldEntry);             // Set New's entry.
 173     return;
 174   }
 175
 176   BBCallbacks[OldEntry.Index] = nullptr;    // Update the callback.
 177
 178   // Otherwise, we need to add the old symbols to the new block's set.
 179   NewEntry.Symbols.insert(NewEntry.Symbols.end(), OldEntry.Symbols.begin(),
 180                           OldEntry.Symbols.end());
 181 }
 182
 183 void MMIAddrLabelMapCallbackPtr::deleted() {
 184   Map->UpdateForDeletedBlock(cast<BasicBlock>(getValPtr()));
 185 }
 186
 187 void MMIAddrLabelMapCallbackPtr::allUsesReplacedWith(Value *V2) {
 188   Map->UpdateForRAUWBlock(cast<BasicBlock>(getValPtr()), cast<BasicBlock>(V2));
 189 }
 190
 191 void MachineModuleInfo::initialize() {
 192   ObjFileMMI = nullptr;
 193   CurCallSite = 0;
 194   UsesMSVCFloatingPoint = UsesMorestackAddr = false;
 195   HasSplitStack = HasNosplitStack = false;
 196   AddrLabelSymbols = nullptr;
 197 }
 198
 199 void MachineModuleInfo::finalize() {
 200   Personalities.clear();
 201
 202   delete AddrLabelSymbols;
 203   AddrLabelSymbols = nullptr;
 204
 205   Context.reset();
 206
 207   delete ObjFileMMI;
 208   ObjFileMMI = nullptr;
 209 }
 210
 211 MachineModuleInfo::MachineModuleInfo(MachineModuleInfo &&MMI)
 212     : TM(std::move(MMI.TM)),
 213       Context(MMI.TM.getMCAsmInfo(), MMI.TM.getMCRegisterInfo(),
 214               MMI.TM.getObjFileLowering(), nullptr, nullptr, false) {
 215   ObjFileMMI = MMI.ObjFileMMI;
 216   CurCallSite = MMI.CurCallSite;
 217   UsesMSVCFloatingPoint = MMI.UsesMSVCFloatingPoint;
 218   UsesMorestackAddr = MMI.UsesMorestackAddr;
 219   HasSplitStack = MMI.HasSplitStack;
 220   HasNosplitStack = MMI.HasNosplitStack;
 221   AddrLabelSymbols = MMI.AddrLabelSymbols;
 222   TheModule = MMI.TheModule;
 223 }
 224
 225 MachineModuleInfo::MachineModuleInfo(const LLVMTargetMachine *TM)
 226     : TM(*TM), Context(TM->getMCAsmInfo(), TM->getMCRegisterInfo(),
 227                        TM->getObjFileLowering(), nullptr, nullptr, false) {
 228   initialize();
 229 }
 230
 231 MachineModuleInfo::~MachineModuleInfo() { finalize(); }
 232
 233 //===- Address of Block Management ----------------------------------------===//
 234
 235 ArrayRef<MCSymbol *>
 236 MachineModuleInfo::getAddrLabelSymbolToEmit(const BasicBlock *BB) {
 237   // Lazily create AddrLabelSymbols.
 238   if (!AddrLabelSymbols)
 239     AddrLabelSymbols = new MMIAddrLabelMap(Context);
 240  return AddrLabelSymbols->getAddrLabelSymbolToEmit(const_cast<BasicBlock*>(BB));
 241 }
 242
 243 void MachineModuleInfo::
 244 takeDeletedSymbolsForFunction(const Function *F,
 245                               std::vector<MCSymbol*> &Result) {
 246   // If no blocks have had their addresses taken, we're done.
 247   if (!AddrLabelSymbols) return;
 248   return AddrLabelSymbols->
 249      takeDeletedSymbolsForFunction(const_cast<Function*>(F), Result);
 250 }
 251
 252 /// \name Exception Handling
 253 /// \{
 254
 255 void MachineModuleInfo::addPersonality(const Function *Personality) {
 256   for (unsigned i = 0; i < Personalities.size(); ++i)
 257     if (Personalities[i] == Personality)
 258       return;
 259   Personalities.push_back(Personality);
 260 }
 261
 262 /// \}
 263
 264 MachineFunction *
 265 MachineModuleInfo::getMachineFunction(const Function &F) const {
 266   auto I = MachineFunctions.find(&F);
 267   return I != MachineFunctions.end() ? I->second.get() : nullptr;
 268 }
 269
 270 MachineFunction &
 271 MachineModuleInfo::getOrCreateMachineFunction(const Function &F) {
 272   // Shortcut for the common case where a sequence of MachineFunctionPasses
 273   // all query for the same Function.
 274   if (LastRequest == &F)
 275     return *LastResult;
 276
 277   auto I = MachineFunctions.insert(
 278       std::make_pair(&F, std::unique_ptr<MachineFunction>()));
 279   MachineFunction *MF;
 280   if (I.second) {
 281     // No pre-existing machine function, create a new one.
 282     const TargetSubtargetInfo &STI = *TM.getSubtargetImpl(F);
 283     MF = new MachineFunction(F, TM, STI, NextFnNum++, *this);
 284     // Update the set entry.
 285     I.first->second.reset(MF);
 286   } else {
 287     MF = I.first->second.get();
 288   }
 289
 290   LastRequest = &F;
 291   LastResult = MF;
 292   return *MF;
 293 }
 294
 295 void MachineModuleInfo::deleteMachineFunctionFor(Function &F) {
 296   MachineFunctions.erase(&F);
 297   LastRequest = nullptr;
 298   LastResult = nullptr;
 299 }
 300
 301 namespace {
 302
 303 /// This pass frees the MachineFunction object associated with a Function.
 304 class FreeMachineFunction : public FunctionPass {
 305 public:
 306   static char ID;
 307
 308   FreeMachineFunction() : FunctionPass(ID) {}
 309
 310   void getAnalysisUsage(AnalysisUsage &AU) const override {
 311     AU.addRequired<MachineModuleInfoWrapperPass>();
 312     AU.addPreserved<MachineModuleInfoWrapperPass>();
 313   }
 314
 315   bool runOnFunction(Function &F) override {
 316     MachineModuleInfo &MMI =
 317         getAnalysis<MachineModuleInfoWrapperPass>().getMMI();
 318     MMI.deleteMachineFunctionFor(F);
 319     return true;
 320   }
 321
 322   StringRef getPassName() const override {
 323     return "Free MachineFunction";
 324   }
 325 };
 326
 327 } // end anonymous namespace
 328
 329 char FreeMachineFunction::ID;
 330
 331 FunctionPass *llvm::createFreeMachineFunctionPass() {
 332   return new FreeMachineFunction();
 333 }
 334
 335 MachineModuleInfoWrapperPass::MachineModuleInfoWrapperPass(
 336     const LLVMTargetMachine *TM)
 337     : ImmutablePass(ID), MMI(TM) {
 338   initializeMachineModuleInfoWrapperPassPass(*PassRegistry::getPassRegistry());
 339 }
 340
 341 // Handle the Pass registration stuff necessary to use DataLayout's.
 342 INITIALIZE_PASS(MachineModuleInfoWrapperPass, "machinemoduleinfo",
 343                 "Machine Module Information", false, false)
 344 char MachineModuleInfoWrapperPass::ID = 0;
 345
 346 bool MachineModuleInfoWrapperPass::doInitialization(Module &M) {
 347   MMI.initialize();
 348   MMI.TheModule = &M;
 349   MMI.DbgInfoAvailable = !M.debug_compile_units().empty();
 350   return false;
 351 }
 352
 353 bool MachineModuleInfoWrapperPass::doFinalization(Module &M) {
 354   MMI.finalize();
 355   return false;
 356 }
 357
 358 AnalysisKey MachineModuleAnalysis::Key;
 359
 360 MachineModuleInfo MachineModuleAnalysis::run(Module &M,
 361                                              ModuleAnalysisManager &) {
 362   MachineModuleInfo MMI(TM);
 363   MMI.TheModule = &M;
 364   MMI.DbgInfoAvailable = !M.debug_compile_units().empty();
 365   return MMI;
 366 }