1 //===- LLVMContextImpl.cpp - Implement LLVMContextImpl --------------------===//
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 opaque LLVMContextImpl.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "LLVMContextImpl.h"
14 #include "llvm/IR/Module.h"
15 #include "llvm/IR/OptBisect.h"
16 #include "llvm/IR/Type.h"
17 #include "llvm/Support/ManagedStatic.h"
18 #include <cassert>
19 #include <utility>
20 
21 using namespace llvm;
22 
23 LLVMContextImpl::LLVMContextImpl(LLVMContext &C)
24   : DiagHandler(std::make_unique<DiagnosticHandler>()),
25     VoidTy(C, Type::VoidTyID),
26     LabelTy(C, Type::LabelTyID),
27     HalfTy(C, Type::HalfTyID),
28     FloatTy(C, Type::FloatTyID),
29     DoubleTy(C, Type::DoubleTyID),
30     MetadataTy(C, Type::MetadataTyID),
31     TokenTy(C, Type::TokenTyID),
32     X86_FP80Ty(C, Type::X86_FP80TyID),
33     FP128Ty(C, Type::FP128TyID),
34     PPC_FP128Ty(C, Type::PPC_FP128TyID),
35     X86_MMXTy(C, Type::X86_MMXTyID),
36     Int1Ty(C, 1),
37     Int8Ty(C, 8),
38     Int16Ty(C, 16),
39     Int32Ty(C, 32),
40     Int64Ty(C, 64),
41     Int128Ty(C, 128) {}
42 
43 LLVMContextImpl::~LLVMContextImpl() {
44   // NOTE: We need to delete the contents of OwnedModules, but Module's dtor
45   // will call LLVMContextImpl::removeModule, thus invalidating iterators into
46   // the container. Avoid iterators during this operation:
47   while (!OwnedModules.empty())
48     delete *OwnedModules.begin();
49 
50 #ifndef NDEBUG
51   // Check for metadata references from leaked Instructions.
52   for (auto &Pair : InstructionMetadata)
53     Pair.first->dump();
54   assert(InstructionMetadata.empty() &&
55          "Instructions with metadata have been leaked");
56 #endif
57 
58   // Drop references for MDNodes.  Do this before Values get deleted to avoid
59   // unnecessary RAUW when nodes are still unresolved.
60   for (auto *I : DistinctMDNodes)
61     I->dropAllReferences();
62 #define HANDLE_MDNODE_LEAF_UNIQUABLE(CLASS)                                    \
63   for (auto *I : CLASS##s)                                                     \
64     I->dropAllReferences();
65 #include "llvm/IR/Metadata.def"
66 
67   // Also drop references that come from the Value bridges.
68   for (auto &Pair : ValuesAsMetadata)
69     Pair.second->dropUsers();
70   for (auto &Pair : MetadataAsValues)
71     Pair.second->dropUse();
72 
73   // Destroy MDNodes.
74   for (MDNode *I : DistinctMDNodes)
75     I->deleteAsSubclass();
76 #define HANDLE_MDNODE_LEAF_UNIQUABLE(CLASS)                                    \
77   for (CLASS * I : CLASS##s)                                                   \
78     delete I;
79 #include "llvm/IR/Metadata.def"
80 
81   // Free the constants.
82   for (auto *I : ExprConstants)
83     I->dropAllReferences();
84   for (auto *I : ArrayConstants)
85     I->dropAllReferences();
86   for (auto *I : StructConstants)
87     I->dropAllReferences();
88   for (auto *I : VectorConstants)
89     I->dropAllReferences();
90   ExprConstants.freeConstants();
91   ArrayConstants.freeConstants();
92   StructConstants.freeConstants();
93   VectorConstants.freeConstants();
94   InlineAsms.freeConstants();
95 
96   CAZConstants.clear();
97   CPNConstants.clear();
98   UVConstants.clear();
99   IntConstants.clear();
100   FPConstants.clear();
101 
102   for (auto &CDSConstant : CDSConstants)
103     delete CDSConstant.second;
104   CDSConstants.clear();
105 
106   // Destroy attributes.
107   for (FoldingSetIterator<AttributeImpl> I = AttrsSet.begin(),
108          E = AttrsSet.end(); I != E; ) {
109     FoldingSetIterator<AttributeImpl> Elem = I++;
110     delete &*Elem;
111   }
112 
113   // Destroy attribute lists.
114   for (FoldingSetIterator<AttributeListImpl> I = AttrsLists.begin(),
115                                              E = AttrsLists.end();
116        I != E;) {
117     FoldingSetIterator<AttributeListImpl> Elem = I++;
118     delete &*Elem;
119   }
120 
121   // Destroy attribute node lists.
122   for (FoldingSetIterator<AttributeSetNode> I = AttrsSetNodes.begin(),
123          E = AttrsSetNodes.end(); I != E; ) {
124     FoldingSetIterator<AttributeSetNode> Elem = I++;
125     delete &*Elem;
126   }
127 
128   // Destroy MetadataAsValues.
129   {
130     SmallVector<MetadataAsValue *, 8> MDVs;
131     MDVs.reserve(MetadataAsValues.size());
132     for (auto &Pair : MetadataAsValues)
133       MDVs.push_back(Pair.second);
134     MetadataAsValues.clear();
135     for (auto *V : MDVs)
136       delete V;
137   }
138 
139   // Destroy ValuesAsMetadata.
140   for (auto &Pair : ValuesAsMetadata)
141     delete Pair.second;
142 }
143 
144 void LLVMContextImpl::dropTriviallyDeadConstantArrays() {
145   bool Changed;
146   do {
147     Changed = false;
148 
149     for (auto I = ArrayConstants.begin(), E = ArrayConstants.end(); I != E;) {
150       auto *C = *I++;
151       if (C->use_empty()) {
152         Changed = true;
153         C->destroyConstant();
154       }
155     }
156   } while (Changed);
157 }
158 
159 void Module::dropTriviallyDeadConstantArrays() {
160   Context.pImpl->dropTriviallyDeadConstantArrays();
161 }
162 
163 namespace llvm {
164 
165 /// Make MDOperand transparent for hashing.
166 ///
167 /// This overload of an implementation detail of the hashing library makes
168 /// MDOperand hash to the same value as a \a Metadata pointer.
169 ///
170 /// Note that overloading \a hash_value() as follows:
171 ///
172 /// \code
173 ///     size_t hash_value(const MDOperand &X) { return hash_value(X.get()); }
174 /// \endcode
175 ///
176 /// does not cause MDOperand to be transparent.  In particular, a bare pointer
177 /// doesn't get hashed before it's combined, whereas \a MDOperand would.
178 static const Metadata *get_hashable_data(const MDOperand &X) { return X.get(); }
179 
180 } // end namespace llvm
181 
182 unsigned MDNodeOpsKey::calculateHash(MDNode *N, unsigned Offset) {
183   unsigned Hash = hash_combine_range(N->op_begin() + Offset, N->op_end());
184 #ifndef NDEBUG
185   {
186     SmallVector<Metadata *, 8> MDs(N->op_begin() + Offset, N->op_end());
187     unsigned RawHash = calculateHash(MDs);
188     assert(Hash == RawHash &&
189            "Expected hash of MDOperand to equal hash of Metadata*");
190   }
191 #endif
192   return Hash;
193 }
194 
195 unsigned MDNodeOpsKey::calculateHash(ArrayRef<Metadata *> Ops) {
196   return hash_combine_range(Ops.begin(), Ops.end());
197 }
198 
199 StringMapEntry<uint32_t> *LLVMContextImpl::getOrInsertBundleTag(StringRef Tag) {
200   uint32_t NewIdx = BundleTagCache.size();
201   return &*(BundleTagCache.insert(std::make_pair(Tag, NewIdx)).first);
202 }
203 
204 void LLVMContextImpl::getOperandBundleTags(SmallVectorImpl<StringRef> &Tags) const {
205   Tags.resize(BundleTagCache.size());
206   for (const auto &T : BundleTagCache)
207     Tags[T.second] = T.first();
208 }
209 
210 uint32_t LLVMContextImpl::getOperandBundleTagID(StringRef Tag) const {
211   auto I = BundleTagCache.find(Tag);
212   assert(I != BundleTagCache.end() && "Unknown tag!");
213   return I->second;
214 }
215 
216 SyncScope::ID LLVMContextImpl::getOrInsertSyncScopeID(StringRef SSN) {
217   auto NewSSID = SSC.size();
218   assert(NewSSID < std::numeric_limits<SyncScope::ID>::max() &&
219          "Hit the maximum number of synchronization scopes allowed!");
220   return SSC.insert(std::make_pair(SSN, SyncScope::ID(NewSSID))).first->second;
221 }
222 
223 void LLVMContextImpl::getSyncScopeNames(
224     SmallVectorImpl<StringRef> &SSNs) const {
225   SSNs.resize(SSC.size());
226   for (const auto &SSE : SSC)
227     SSNs[SSE.second] = SSE.first();
228 }
229 
230 /// Singleton instance of the OptBisect class.
231 ///
232 /// This singleton is accessed via the LLVMContext::getOptPassGate() function.
233 /// It provides a mechanism to disable passes and individual optimizations at
234 /// compile time based on a command line option (-opt-bisect-limit) in order to
235 /// perform a bisecting search for optimization-related problems.
236 ///
237 /// Even if multiple LLVMContext objects are created, they will all return the
238 /// same instance of OptBisect in order to provide a single bisect count.  Any
239 /// code that uses the OptBisect object should be serialized when bisection is
240 /// enabled in order to enable a consistent bisect count.
241 static ManagedStatic<OptBisect> OptBisector;
242 
243 OptPassGate &LLVMContextImpl::getOptPassGate() const {
244   if (!OPG)
245     OPG = &(*OptBisector);
246   return *OPG;
247 }
248 
249 void LLVMContextImpl::setOptPassGate(OptPassGate& OPG) {
250   this->OPG = &OPG;
251 }
252