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1 //===-- GCMetadata.cpp - Garbage collector metadata -----------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements the GCFunctionInfo class and GCModuleInfo pass.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/CodeGen/GCMetadata.h"
15 #include "llvm/CodeGen/GCStrategy.h"
16 #include "llvm/CodeGen/MachineFrameInfo.h"
17 #include "llvm/CodeGen/Passes.h"
18 #include "llvm/IR/Function.h"
19 #include "llvm/MC/MCSymbol.h"
20 #include "llvm/Pass.h"
21 #include "llvm/Support/Debug.h"
22 #include "llvm/Support/ErrorHandling.h"
23 #include "llvm/Support/raw_ostream.h"
24 using namespace llvm;
25 
26 namespace {
27 
28 class Printer : public FunctionPass {
29   static char ID;
30   raw_ostream &OS;
31 
32 public:
Printer(raw_ostream & OS)33   explicit Printer(raw_ostream &OS) : FunctionPass(ID), OS(OS) {}
34 
35   const char *getPassName() const override;
36   void getAnalysisUsage(AnalysisUsage &AU) const override;
37 
38   bool runOnFunction(Function &F) override;
39   bool doFinalization(Module &M) override;
40 };
41 }
42 
43 INITIALIZE_PASS(GCModuleInfo, "collector-metadata",
44                 "Create Garbage Collector Module Metadata", false, false)
45 
46 // -----------------------------------------------------------------------------
47 
GCFunctionInfo(const Function & F,GCStrategy & S)48 GCFunctionInfo::GCFunctionInfo(const Function &F, GCStrategy &S)
49     : F(F), S(S), FrameSize(~0LL) {}
50 
~GCFunctionInfo()51 GCFunctionInfo::~GCFunctionInfo() {}
52 
53 // -----------------------------------------------------------------------------
54 
55 char GCModuleInfo::ID = 0;
56 
GCModuleInfo()57 GCModuleInfo::GCModuleInfo() : ImmutablePass(ID) {
58   initializeGCModuleInfoPass(*PassRegistry::getPassRegistry());
59 }
60 
getFunctionInfo(const Function & F)61 GCFunctionInfo &GCModuleInfo::getFunctionInfo(const Function &F) {
62   assert(!F.isDeclaration() && "Can only get GCFunctionInfo for a definition!");
63   assert(F.hasGC());
64 
65   finfo_map_type::iterator I = FInfoMap.find(&F);
66   if (I != FInfoMap.end())
67     return *I->second;
68 
69   GCStrategy *S = getGCStrategy(F.getGC());
70   Functions.push_back(make_unique<GCFunctionInfo>(F, *S));
71   GCFunctionInfo *GFI = Functions.back().get();
72   FInfoMap[&F] = GFI;
73   return *GFI;
74 }
75 
clear()76 void GCModuleInfo::clear() {
77   Functions.clear();
78   FInfoMap.clear();
79   GCStrategyList.clear();
80 }
81 
82 // -----------------------------------------------------------------------------
83 
84 char Printer::ID = 0;
85 
createGCInfoPrinter(raw_ostream & OS)86 FunctionPass *llvm::createGCInfoPrinter(raw_ostream &OS) {
87   return new Printer(OS);
88 }
89 
getPassName() const90 const char *Printer::getPassName() const {
91   return "Print Garbage Collector Information";
92 }
93 
getAnalysisUsage(AnalysisUsage & AU) const94 void Printer::getAnalysisUsage(AnalysisUsage &AU) const {
95   FunctionPass::getAnalysisUsage(AU);
96   AU.setPreservesAll();
97   AU.addRequired<GCModuleInfo>();
98 }
99 
DescKind(GC::PointKind Kind)100 static const char *DescKind(GC::PointKind Kind) {
101   switch (Kind) {
102   case GC::PreCall:
103     return "pre-call";
104   case GC::PostCall:
105     return "post-call";
106   }
107   llvm_unreachable("Invalid point kind");
108 }
109 
runOnFunction(Function & F)110 bool Printer::runOnFunction(Function &F) {
111   if (F.hasGC())
112     return false;
113 
114   GCFunctionInfo *FD = &getAnalysis<GCModuleInfo>().getFunctionInfo(F);
115 
116   OS << "GC roots for " << FD->getFunction().getName() << ":\n";
117   for (GCFunctionInfo::roots_iterator RI = FD->roots_begin(),
118                                       RE = FD->roots_end();
119        RI != RE; ++RI)
120     OS << "\t" << RI->Num << "\t" << RI->StackOffset << "[sp]\n";
121 
122   OS << "GC safe points for " << FD->getFunction().getName() << ":\n";
123   for (GCFunctionInfo::iterator PI = FD->begin(), PE = FD->end(); PI != PE;
124        ++PI) {
125 
126     OS << "\t" << PI->Label->getName() << ": " << DescKind(PI->Kind)
127        << ", live = {";
128 
129     for (GCFunctionInfo::live_iterator RI = FD->live_begin(PI),
130                                        RE = FD->live_end(PI);
131          ;) {
132       OS << " " << RI->Num;
133       if (++RI == RE)
134         break;
135       OS << ",";
136     }
137 
138     OS << " }\n";
139   }
140 
141   return false;
142 }
143 
doFinalization(Module & M)144 bool Printer::doFinalization(Module &M) {
145   GCModuleInfo *GMI = getAnalysisIfAvailable<GCModuleInfo>();
146   assert(GMI && "Printer didn't require GCModuleInfo?!");
147   GMI->clear();
148   return false;
149 }
150 
getGCStrategy(const StringRef Name)151 GCStrategy *GCModuleInfo::getGCStrategy(const StringRef Name) {
152   // TODO: Arguably, just doing a linear search would be faster for small N
153   auto NMI = GCStrategyMap.find(Name);
154   if (NMI != GCStrategyMap.end())
155     return NMI->getValue();
156 
157   for (auto& Entry : GCRegistry::entries()) {
158     if (Name == Entry.getName()) {
159       std::unique_ptr<GCStrategy> S = Entry.instantiate();
160       S->Name = Name;
161       GCStrategyMap[Name] = S.get();
162       GCStrategyList.push_back(std::move(S));
163       return GCStrategyList.back().get();
164     }
165   }
166 
167   if (GCRegistry::begin() == GCRegistry::end()) {
168     // In normal operation, the registry should not be empty.  There should
169     // be the builtin GCs if nothing else.  The most likely scenario here is
170     // that we got here without running the initializers used by the Registry
171     // itself and it's registration mechanism.
172     const std::string error = ("unsupported GC: " + Name).str() +
173       " (did you remember to link and initialize the CodeGen library?)";
174     report_fatal_error(error);
175   } else
176     report_fatal_error(std::string("unsupported GC: ") + Name);
177 }
178