lib/CodeGen/GCMetadata.cpp

   1 //===-- GCMetadata.cpp - Garbage collector metadata -----------------------===//
   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 implements the GCFunctionInfo class and GCModuleInfo pass.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "llvm/ADT/STLExtras.h"
  14 #include "llvm/CodeGen/GCMetadata.h"
  15 #include "llvm/CodeGen/GCStrategy.h"
  16 #include "llvm/CodeGen/Passes.h"
  17 #include "llvm/IR/Function.h"
  18 #include "llvm/MC/MCSymbol.h"
  19 #include "llvm/Pass.h"
  20 #include "llvm/Support/ErrorHandling.h"
  21 #include "llvm/Support/raw_ostream.h"
  22 #include <algorithm>
  23 #include <cassert>
  24 #include <memory>
  25 #include <string>
  26
  27 using namespace llvm;
  28
  29 namespace {
  30
  31 class Printer : public FunctionPass {
  32   static char ID;
  33
  34   raw_ostream &OS;
  35
  36 public:
  37   explicit Printer(raw_ostream &OS) : FunctionPass(ID), OS(OS) {}
  38
  39   StringRef getPassName() const override;
  40   void getAnalysisUsage(AnalysisUsage &AU) const override;
  41
  42   bool runOnFunction(Function &F) override;
  43   bool doFinalization(Module &M) override;
  44 };
  45
  46 } // end anonymous namespace
  47
  48 INITIALIZE_PASS(GCModuleInfo, "collector-metadata",
  49                 "Create Garbage Collector Module Metadata", false, false)
  50
  51 // -----------------------------------------------------------------------------
  52
  53 GCFunctionInfo::GCFunctionInfo(const Function &F, GCStrategy &S)
  54     : F(F), S(S), FrameSize(~0LL) {}
  55
  56 GCFunctionInfo::~GCFunctionInfo() = default;
  57
  58 // -----------------------------------------------------------------------------
  59
  60 char GCModuleInfo::ID = 0;
  61
  62 GCModuleInfo::GCModuleInfo() : ImmutablePass(ID) {
  63   initializeGCModuleInfoPass(*PassRegistry::getPassRegistry());
  64 }
  65
  66 GCFunctionInfo &GCModuleInfo::getFunctionInfo(const Function &F) {
  67   assert(!F.isDeclaration() && "Can only get GCFunctionInfo for a definition!");
  68   assert(F.hasGC());
  69
  70   finfo_map_type::iterator I = FInfoMap.find(&F);
  71   if (I != FInfoMap.end())
  72     return *I->second;
  73
  74   GCStrategy *S = getGCStrategy(F.getGC());
  75   Functions.push_back(std::make_unique<GCFunctionInfo>(F, *S));
  76   GCFunctionInfo *GFI = Functions.back().get();
  77   FInfoMap[&F] = GFI;
  78   return *GFI;
  79 }
  80
  81 void GCModuleInfo::clear() {
  82   Functions.clear();
  83   FInfoMap.clear();
  84   GCStrategyList.clear();
  85 }
  86
  87 // -----------------------------------------------------------------------------
  88
  89 char Printer::ID = 0;
  90
  91 FunctionPass *llvm::createGCInfoPrinter(raw_ostream &OS) {
  92   return new Printer(OS);
  93 }
  94
  95 StringRef Printer::getPassName() const {
  96   return "Print Garbage Collector Information";
  97 }
  98
  99 void Printer::getAnalysisUsage(AnalysisUsage &AU) const {
 100   FunctionPass::getAnalysisUsage(AU);
 101   AU.setPreservesAll();
 102   AU.addRequired<GCModuleInfo>();
 103 }
 104
 105 bool Printer::runOnFunction(Function &F) {
 106   if (F.hasGC())
 107     return false;
 108
 109   GCFunctionInfo *FD = &getAnalysis<GCModuleInfo>().getFunctionInfo(F);
 110
 111   OS << "GC roots for " << FD->getFunction().getName() << ":\n";
 112   for (GCFunctionInfo::roots_iterator RI = FD->roots_begin(),
 113                                       RE = FD->roots_end();
 114        RI != RE; ++RI)
 115     OS << "\t" << RI->Num << "\t" << RI->StackOffset << "[sp]\n";
 116
 117   OS << "GC safe points for " << FD->getFunction().getName() << ":\n";
 118   for (GCFunctionInfo::iterator PI = FD->begin(), PE = FD->end(); PI != PE;
 119        ++PI) {
 120
 121     OS << "\t" << PI->Label->getName() << ": " << "post-call"
 122        << ", live = {";
 123
 124     for (GCFunctionInfo::live_iterator RI = FD->live_begin(PI),
 125                                        RE = FD->live_end(PI);
 126          ;) {
 127       OS << " " << RI->Num;
 128       if (++RI == RE)
 129         break;
 130       OS << ",";
 131     }
 132
 133     OS << " }\n";
 134   }
 135
 136   return false;
 137 }
 138
 139 bool Printer::doFinalization(Module &M) {
 140   GCModuleInfo *GMI = getAnalysisIfAvailable<GCModuleInfo>();
 141   assert(GMI && "Printer didn't require GCModuleInfo?!");
 142   GMI->clear();
 143   return false;
 144 }
 145
 146 GCStrategy *GCModuleInfo::getGCStrategy(const StringRef Name) {
 147   // TODO: Arguably, just doing a linear search would be faster for small N
 148   auto NMI = GCStrategyMap.find(Name);
 149   if (NMI != GCStrategyMap.end())
 150     return NMI->getValue();
 151
 152   for (auto& Entry : GCRegistry::entries()) {
 153     if (Name == Entry.getName()) {
 154       std::unique_ptr<GCStrategy> S = Entry.instantiate();
 155       S->Name = Name;
 156       GCStrategyMap[Name] = S.get();
 157       GCStrategyList.push_back(std::move(S));
 158       return GCStrategyList.back().get();
 159     }
 160   }
 161
 162   if (GCRegistry::begin() == GCRegistry::end()) {
 163     // In normal operation, the registry should not be empty.  There should
 164     // be the builtin GCs if nothing else.  The most likely scenario here is
 165     // that we got here without running the initializers used by the Registry
 166     // itself and it's registration mechanism.
 167     const std::string error = ("unsupported GC: " + Name).str() +
 168       " (did you remember to link and initialize the CodeGen library?)";
 169     report_fatal_error(error);
 170   } else
 171     report_fatal_error(std::string("unsupported GC: ") + Name);
 172 }