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