GCMetadata.cpp revision 360784 
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/CodeGen/GCMetadata.h"
14#include "llvm/ADT/STLExtras.h"
15#include "llvm/CodeGen/GCStrategy.h"
16#include "llvm/CodeGen/Passes.h"
17#include "llvm/IR/Function.h"
18#include "llvm/InitializePasses.h"
19#include "llvm/MC/MCSymbol.h"
20#include "llvm/Pass.h"
21#include "llvm/Support/ErrorHandling.h"
22#include "llvm/Support/raw_ostream.h"
23#include <algorithm>
24#include <cassert>
25#include <memory>
26#include <string>
27
28using namespace llvm;
29
30namespace {
31
32class Printer : public FunctionPass {
33  static char ID;
34
35  raw_ostream &OS;
36
37public:
38  explicit Printer(raw_ostream &OS) : FunctionPass(ID), OS(OS) {}
39
40  StringRef getPassName() const override;
41  void getAnalysisUsage(AnalysisUsage &AU) const override;
42
43  bool runOnFunction(Function &F) override;
44  bool doFinalization(Module &M) override;
45};
46
47} // end anonymous namespace
48
49INITIALIZE_PASS(GCModuleInfo, "collector-metadata",
50                "Create Garbage Collector Module Metadata", false, false)
51
52// -----------------------------------------------------------------------------
53
54GCFunctionInfo::GCFunctionInfo(const Function &F, GCStrategy &S)
55    : F(F), S(S), FrameSize(~0LL) {}
56
57GCFunctionInfo::~GCFunctionInfo() = default;
58
59// -----------------------------------------------------------------------------
60
61char GCModuleInfo::ID = 0;
62
63GCModuleInfo::GCModuleInfo() : ImmutablePass(ID) {
64  initializeGCModuleInfoPass(*PassRegistry::getPassRegistry());
65}
66
67GCFunctionInfo &GCModuleInfo::getFunctionInfo(const Function &F) {
68  assert(!F.isDeclaration() && "Can only get GCFunctionInfo for a definition!");
69  assert(F.hasGC());
70
71  finfo_map_type::iterator I = FInfoMap.find(&F);
72  if (I != FInfoMap.end())
73    return *I->second;
74
75  GCStrategy *S = getGCStrategy(F.getGC());
76  Functions.push_back(std::make_unique<GCFunctionInfo>(F, *S));
77  GCFunctionInfo *GFI = Functions.back().get();
78  FInfoMap[&F] = GFI;
79  return *GFI;
80}
81
82void GCModuleInfo::clear() {
83  Functions.clear();
84  FInfoMap.clear();
85  GCStrategyList.clear();
86}
87
88// -----------------------------------------------------------------------------
89
90char Printer::ID = 0;
91
92FunctionPass *llvm::createGCInfoPrinter(raw_ostream &OS) {
93  return new Printer(OS);
94}
95
96StringRef Printer::getPassName() const {
97  return "Print Garbage Collector Information";
98}
99
100void Printer::getAnalysisUsage(AnalysisUsage &AU) const {
101  FunctionPass::getAnalysisUsage(AU);
102  AU.setPreservesAll();
103  AU.addRequired<GCModuleInfo>();
104}
105
106bool Printer::runOnFunction(Function &F) {
107  if (F.hasGC())
108    return false;
109
110  GCFunctionInfo *FD = &getAnalysis<GCModuleInfo>().getFunctionInfo(F);
111
112  OS << "GC roots for " << FD->getFunction().getName() << ":\n";
113  for (GCFunctionInfo::roots_iterator RI = FD->roots_begin(),
114                                      RE = FD->roots_end();
115       RI != RE; ++RI)
116    OS << "\t" << RI->Num << "\t" << RI->StackOffset << "[sp]\n";
117
118  OS << "GC safe points for " << FD->getFunction().getName() << ":\n";
119  for (GCFunctionInfo::iterator PI = FD->begin(), PE = FD->end(); PI != PE;
120       ++PI) {
121
122    OS << "\t" << PI->Label->getName() << ": " << "post-call"
123       << ", live = {";
124
125    for (GCFunctionInfo::live_iterator RI = FD->live_begin(PI),
126                                       RE = FD->live_end(PI);
127         ;) {
128      OS << " " << RI->Num;
129      if (++RI == RE)
130        break;
131      OS << ",";
132    }
133
134    OS << " }\n";
135  }
136
137  return false;
138}
139
140bool Printer::doFinalization(Module &M) {
141  GCModuleInfo *GMI = getAnalysisIfAvailable<GCModuleInfo>();
142  assert(GMI && "Printer didn't require GCModuleInfo?!");
143  GMI->clear();
144  return false;
145}
146
147GCStrategy *GCModuleInfo::getGCStrategy(const StringRef Name) {
148  // TODO: Arguably, just doing a linear search would be faster for small N
149  auto NMI = GCStrategyMap.find(Name);
150  if (NMI != GCStrategyMap.end())
151    return NMI->getValue();
152
153  for (auto& Entry : GCRegistry::entries()) {
154    if (Name == Entry.getName()) {
155      std::unique_ptr<GCStrategy> S = Entry.instantiate();
156      S->Name = Name;
157      GCStrategyMap[Name] = S.get();
158      GCStrategyList.push_back(std::move(S));
159      return GCStrategyList.back().get();
160    }
161  }
162
163  if (GCRegistry::begin() == GCRegistry::end()) {
164    // In normal operation, the registry should not be empty.  There should
165    // be the builtin GCs if nothing else.  The most likely scenario here is
166    // that we got here without running the initializers used by the Registry
167    // itself and it's registration mechanism.
168    const std::string error = ("unsupported GC: " + Name).str() +
169      " (did you remember to link and initialize the CodeGen library?)";
170    report_fatal_error(error);
171  } else
172    report_fatal_error(std::string("unsupported GC: ") + Name);
173}
174