1 //===- LLVMContextImpl.cpp - Implement LLVMContextImpl --------------------===//
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 opaque LLVMContextImpl.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "LLVMContextImpl.h"
15 #include "llvm/IR/Module.h"
16 #include "llvm/IR/OptBisect.h"
17 #include "llvm/IR/Type.h"
18 #include "llvm/Support/ManagedStatic.h"
19 #include <cassert>
20 #include <utility>
21 
22 using namespace llvm;
23 
24 LLVMContextImpl::LLVMContextImpl(LLVMContext &C)
25   : DiagHandler(llvm::make_unique<DiagnosticHandler>()),
26     VoidTy(C, Type::VoidTyID),
27     LabelTy(C, Type::LabelTyID),
28     HalfTy(C, Type::HalfTyID),
29     FloatTy(C, Type::FloatTyID),
30     DoubleTy(C, Type::DoubleTyID),
31     MetadataTy(C, Type::MetadataTyID),
32     TokenTy(C, Type::TokenTyID),
33     X86_FP80Ty(C, Type::X86_FP80TyID),
34     FP128Ty(C, Type::FP128TyID),
35     PPC_FP128Ty(C, Type::PPC_FP128TyID),
36     X86_MMXTy(C, Type::X86_MMXTyID),
37     Int1Ty(C, 1),
38     Int8Ty(C, 8),
39     Int16Ty(C, 16),
40     Int32Ty(C, 32),
41     Int64Ty(C, 64),
42     Int128Ty(C, 128) {}
43 
44 LLVMContextImpl::~LLVMContextImpl() {
45   // NOTE: We need to delete the contents of OwnedModules, but Module's dtor
46   // will call LLVMContextImpl::removeModule, thus invalidating iterators into
47   // the container. Avoid iterators during this operation:
48   while (!OwnedModules.empty())
49     delete *OwnedModules.begin();
50 
51   // Drop references for MDNodes.  Do this before Values get deleted to avoid
52   // unnecessary RAUW when nodes are still unresolved.
53   for (auto *I : DistinctMDNodes)
54     I->dropAllReferences();
55 #define HANDLE_MDNODE_LEAF_UNIQUABLE(CLASS)                                    \
56   for (auto *I : CLASS##s)                                                     \
57     I->dropAllReferences();
58 #include "llvm/IR/Metadata.def"
59 
60   // Also drop references that come from the Value bridges.
61   for (auto &Pair : ValuesAsMetadata)
62     Pair.second->dropUsers();
63   for (auto &Pair : MetadataAsValues)
64     Pair.second->dropUse();
65 
66   // Destroy MDNodes.
67   for (MDNode *I : DistinctMDNodes)
68     I->deleteAsSubclass();
69 #define HANDLE_MDNODE_LEAF_UNIQUABLE(CLASS)                                    \
70   for (CLASS * I : CLASS##s)                                                   \
71     delete I;
72 #include "llvm/IR/Metadata.def"
73 
74   // Free the constants.
75   for (auto *I : ExprConstants)
76     I->dropAllReferences();
77   for (auto *I : ArrayConstants)
78     I->dropAllReferences();
79   for (auto *I : StructConstants)
80     I->dropAllReferences();
81   for (auto *I : VectorConstants)
82     I->dropAllReferences();
83   ExprConstants.freeConstants();
84   ArrayConstants.freeConstants();
85   StructConstants.freeConstants();
86   VectorConstants.freeConstants();
87   InlineAsms.freeConstants();
88 
89   CAZConstants.clear();
90   CPNConstants.clear();
91   UVConstants.clear();
92   IntConstants.clear();
93   FPConstants.clear();
94 
95   for (auto &CDSConstant : CDSConstants)
96     delete CDSConstant.second;
97   CDSConstants.clear();
98 
99   // Destroy attributes.
100   for (FoldingSetIterator<AttributeImpl> I = AttrsSet.begin(),
101          E = AttrsSet.end(); I != E; ) {
102     FoldingSetIterator<AttributeImpl> Elem = I++;
103     delete &*Elem;
104   }
105 
106   // Destroy attribute lists.
107   for (FoldingSetIterator<AttributeListImpl> I = AttrsLists.begin(),
108                                              E = AttrsLists.end();
109        I != E;) {
110     FoldingSetIterator<AttributeListImpl> Elem = I++;
111     delete &*Elem;
112   }
113 
114   // Destroy attribute node lists.
115   for (FoldingSetIterator<AttributeSetNode> I = AttrsSetNodes.begin(),
116          E = AttrsSetNodes.end(); I != E; ) {
117     FoldingSetIterator<AttributeSetNode> Elem = I++;
118     delete &*Elem;
119   }
120 
121   // Destroy MetadataAsValues.
122   {
123     SmallVector<MetadataAsValue *, 8> MDVs;
124     MDVs.reserve(MetadataAsValues.size());
125     for (auto &Pair : MetadataAsValues)
126       MDVs.push_back(Pair.second);
127     MetadataAsValues.clear();
128     for (auto *V : MDVs)
129       delete V;
130   }
131 
132   // Destroy ValuesAsMetadata.
133   for (auto &Pair : ValuesAsMetadata)
134     delete Pair.second;
135 }
136 
137 void LLVMContextImpl::dropTriviallyDeadConstantArrays() {
138   bool Changed;
139   do {
140     Changed = false;
141 
142     for (auto I = ArrayConstants.begin(), E = ArrayConstants.end(); I != E;) {
143       auto *C = *I++;
144       if (C->use_empty()) {
145         Changed = true;
146         C->destroyConstant();
147       }
148     }
149   } while (Changed);
150 }
151 
152 void Module::dropTriviallyDeadConstantArrays() {
153   Context.pImpl->dropTriviallyDeadConstantArrays();
154 }
155 
156 namespace llvm {
157 
158 /// \brief Make MDOperand transparent for hashing.
159 ///
160 /// This overload of an implementation detail of the hashing library makes
161 /// MDOperand hash to the same value as a \a Metadata pointer.
162 ///
163 /// Note that overloading \a hash_value() as follows:
164 ///
165 /// \code
166 ///     size_t hash_value(const MDOperand &X) { return hash_value(X.get()); }
167 /// \endcode
168 ///
169 /// does not cause MDOperand to be transparent.  In particular, a bare pointer
170 /// doesn't get hashed before it's combined, whereas \a MDOperand would.
171 static const Metadata *get_hashable_data(const MDOperand &X) { return X.get(); }
172 
173 } // end namespace llvm
174 
175 unsigned MDNodeOpsKey::calculateHash(MDNode *N, unsigned Offset) {
176   unsigned Hash = hash_combine_range(N->op_begin() + Offset, N->op_end());
177 #ifndef NDEBUG
178   {
179     SmallVector<Metadata *, 8> MDs(N->op_begin() + Offset, N->op_end());
180     unsigned RawHash = calculateHash(MDs);
181     assert(Hash == RawHash &&
182            "Expected hash of MDOperand to equal hash of Metadata*");
183   }
184 #endif
185   return Hash;
186 }
187 
188 unsigned MDNodeOpsKey::calculateHash(ArrayRef<Metadata *> Ops) {
189   return hash_combine_range(Ops.begin(), Ops.end());
190 }
191 
192 StringMapEntry<uint32_t> *LLVMContextImpl::getOrInsertBundleTag(StringRef Tag) {
193   uint32_t NewIdx = BundleTagCache.size();
194   return &*(BundleTagCache.insert(std::make_pair(Tag, NewIdx)).first);
195 }
196 
197 void LLVMContextImpl::getOperandBundleTags(SmallVectorImpl<StringRef> &Tags) const {
198   Tags.resize(BundleTagCache.size());
199   for (const auto &T : BundleTagCache)
200     Tags[T.second] = T.first();
201 }
202 
203 uint32_t LLVMContextImpl::getOperandBundleTagID(StringRef Tag) const {
204   auto I = BundleTagCache.find(Tag);
205   assert(I != BundleTagCache.end() && "Unknown tag!");
206   return I->second;
207 }
208 
209 SyncScope::ID LLVMContextImpl::getOrInsertSyncScopeID(StringRef SSN) {
210   auto NewSSID = SSC.size();
211   assert(NewSSID < std::numeric_limits<SyncScope::ID>::max() &&
212          "Hit the maximum number of synchronization scopes allowed!");
213   return SSC.insert(std::make_pair(SSN, SyncScope::ID(NewSSID))).first->second;
214 }
215 
216 void LLVMContextImpl::getSyncScopeNames(
217     SmallVectorImpl<StringRef> &SSNs) const {
218   SSNs.resize(SSC.size());
219   for (const auto &SSE : SSC)
220     SSNs[SSE.second] = SSE.first();
221 }
222 
223 /// Singleton instance of the OptBisect class.
224 ///
225 /// This singleton is accessed via the LLVMContext::getOptBisect() function.  It
226 /// provides a mechanism to disable passes and individual optimizations at
227 /// compile time based on a command line option (-opt-bisect-limit) in order to
228 /// perform a bisecting search for optimization-related problems.
229 ///
230 /// Even if multiple LLVMContext objects are created, they will all return the
231 /// same instance of OptBisect in order to provide a single bisect count.  Any
232 /// code that uses the OptBisect object should be serialized when bisection is
233 /// enabled in order to enable a consistent bisect count.
234 static ManagedStatic<OptBisect> OptBisector;
235 
236 OptBisect &LLVMContextImpl::getOptBisect() {
237   return *OptBisector;
238 }
239