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
28 using namespace llvm;
29
30 namespace {
31
32 class Printer : public FunctionPass {
33 static char ID;
34
35 raw_ostream &OS;
36
37 public:
Printer(raw_ostream & OS)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
49 INITIALIZE_PASS(GCModuleInfo, "collector-metadata",
50 "Create Garbage Collector Module Metadata", false, false)
51
52 // -----------------------------------------------------------------------------
53
GCFunctionInfo(const Function & F,GCStrategy & S)54 GCFunctionInfo::GCFunctionInfo(const Function &F, GCStrategy &S)
55 : F(F), S(S), FrameSize(~0LL) {}
56
57 GCFunctionInfo::~GCFunctionInfo() = default;
58
59 // -----------------------------------------------------------------------------
60
61 char GCModuleInfo::ID = 0;
62
GCModuleInfo()63 GCModuleInfo::GCModuleInfo() : ImmutablePass(ID) {
64 initializeGCModuleInfoPass(*PassRegistry::getPassRegistry());
65 }
66
getFunctionInfo(const Function & F)67 GCFunctionInfo &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
clear()82 void GCModuleInfo::clear() {
83 Functions.clear();
84 FInfoMap.clear();
85 GCStrategyList.clear();
86 }
87
88 // -----------------------------------------------------------------------------
89
90 char Printer::ID = 0;
91
createGCInfoPrinter(raw_ostream & OS)92 FunctionPass *llvm::createGCInfoPrinter(raw_ostream &OS) {
93 return new Printer(OS);
94 }
95
getPassName() const96 StringRef Printer::getPassName() const {
97 return "Print Garbage Collector Information";
98 }
99
getAnalysisUsage(AnalysisUsage & AU) const100 void Printer::getAnalysisUsage(AnalysisUsage &AU) const {
101 FunctionPass::getAnalysisUsage(AU);
102 AU.setPreservesAll();
103 AU.addRequired<GCModuleInfo>();
104 }
105
runOnFunction(Function & F)106 bool 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
doFinalization(Module & M)140 bool 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
getGCStrategy(const StringRef Name)147 GCStrategy *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