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/ADT/SetVector.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(std::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 #ifndef NDEBUG
52   // Check for metadata references from leaked Instructions.
53   for (auto &Pair : InstructionMetadata)
54     Pair.first->dump();
55   assert(InstructionMetadata.empty() &&
56          "Instructions with metadata have been leaked");
57 #endif
58 
59   // Drop references for MDNodes.  Do this before Values get deleted to avoid
60   // unnecessary RAUW when nodes are still unresolved.
61   for (auto *I : DistinctMDNodes)
62     I->dropAllReferences();
63 #define HANDLE_MDNODE_LEAF_UNIQUABLE(CLASS)                                    \
64   for (auto *I : CLASS##s)                                                     \
65     I->dropAllReferences();
66 #include "llvm/IR/Metadata.def"
67 
68   // Also drop references that come from the Value bridges.
69   for (auto &Pair : ValuesAsMetadata)
70     Pair.second->dropUsers();
71   for (auto &Pair : MetadataAsValues)
72     Pair.second->dropUse();
73 
74   // Destroy MDNodes.
75   for (MDNode *I : DistinctMDNodes)
76     I->deleteAsSubclass();
77 #define HANDLE_MDNODE_LEAF_UNIQUABLE(CLASS)                                    \
78   for (CLASS * I : CLASS##s)                                                   \
79     delete I;
80 #include "llvm/IR/Metadata.def"
81 
82   // Free the constants.
83   for (auto *I : ExprConstants)
84     I->dropAllReferences();
85   for (auto *I : ArrayConstants)
86     I->dropAllReferences();
87   for (auto *I : StructConstants)
88     I->dropAllReferences();
89   for (auto *I : VectorConstants)
90     I->dropAllReferences();
91   ExprConstants.freeConstants();
92   ArrayConstants.freeConstants();
93   StructConstants.freeConstants();
94   VectorConstants.freeConstants();
95   InlineAsms.freeConstants();
96 
97   CAZConstants.clear();
98   CPNConstants.clear();
99   UVConstants.clear();
100   IntConstants.clear();
101   FPConstants.clear();
102 
103   for (auto &CDSConstant : CDSConstants)
104     delete CDSConstant.second;
105   CDSConstants.clear();
106 
107   // Destroy attributes.
108   for (FoldingSetIterator<AttributeImpl> I = AttrsSet.begin(),
109          E = AttrsSet.end(); I != E; ) {
110     FoldingSetIterator<AttributeImpl> Elem = I++;
111     delete &*Elem;
112   }
113 
114   // Destroy attribute lists.
115   for (FoldingSetIterator<AttributeListImpl> I = AttrsLists.begin(),
116                                              E = AttrsLists.end();
117        I != E;) {
118     FoldingSetIterator<AttributeListImpl> Elem = I++;
119     delete &*Elem;
120   }
121 
122   // Destroy attribute node lists.
123   for (FoldingSetIterator<AttributeSetNode> I = AttrsSetNodes.begin(),
124          E = AttrsSetNodes.end(); I != E; ) {
125     FoldingSetIterator<AttributeSetNode> Elem = I++;
126     delete &*Elem;
127   }
128 
129   // Destroy MetadataAsValues.
130   {
131     SmallVector<MetadataAsValue *, 8> MDVs;
132     MDVs.reserve(MetadataAsValues.size());
133     for (auto &Pair : MetadataAsValues)
134       MDVs.push_back(Pair.second);
135     MetadataAsValues.clear();
136     for (auto *V : MDVs)
137       delete V;
138   }
139 
140   // Destroy ValuesAsMetadata.
141   for (auto &Pair : ValuesAsMetadata)
142     delete Pair.second;
143 }
144 
145 void LLVMContextImpl::dropTriviallyDeadConstantArrays() {
146   SmallSetVector<ConstantArray *, 4> WorkList(ArrayConstants.begin(),
147                                               ArrayConstants.end());
148 
149   while (!WorkList.empty()) {
150     ConstantArray *C = WorkList.pop_back_val();
151     if (C->use_empty()) {
152       for (const Use &Op : C->operands()) {
153         if (auto *COp = dyn_cast<ConstantArray>(Op))
154           WorkList.insert(COp);
155       }
156       C->destroyConstant();
157     }
158   }
159 }
160 
161 void Module::dropTriviallyDeadConstantArrays() {
162   Context.pImpl->dropTriviallyDeadConstantArrays();
163 }
164 
165 namespace llvm {
166 
167 /// Make MDOperand transparent for hashing.
168 ///
169 /// This overload of an implementation detail of the hashing library makes
170 /// MDOperand hash to the same value as a \a Metadata pointer.
171 ///
172 /// Note that overloading \a hash_value() as follows:
173 ///
174 /// \code
175 ///     size_t hash_value(const MDOperand &X) { return hash_value(X.get()); }
176 /// \endcode
177 ///
178 /// does not cause MDOperand to be transparent.  In particular, a bare pointer
179 /// doesn't get hashed before it's combined, whereas \a MDOperand would.
180 static const Metadata *get_hashable_data(const MDOperand &X) { return X.get(); }
181 
182 } // end namespace llvm
183 
184 unsigned MDNodeOpsKey::calculateHash(MDNode *N, unsigned Offset) {
185   unsigned Hash = hash_combine_range(N->op_begin() + Offset, N->op_end());
186 #ifndef NDEBUG
187   {
188     SmallVector<Metadata *, 8> MDs(N->op_begin() + Offset, N->op_end());
189     unsigned RawHash = calculateHash(MDs);
190     assert(Hash == RawHash &&
191            "Expected hash of MDOperand to equal hash of Metadata*");
192   }
193 #endif
194   return Hash;
195 }
196 
197 unsigned MDNodeOpsKey::calculateHash(ArrayRef<Metadata *> Ops) {
198   return hash_combine_range(Ops.begin(), Ops.end());
199 }
200 
201 StringMapEntry<uint32_t> *LLVMContextImpl::getOrInsertBundleTag(StringRef Tag) {
202   uint32_t NewIdx = BundleTagCache.size();
203   return &*(BundleTagCache.insert(std::make_pair(Tag, NewIdx)).first);
204 }
205 
206 void LLVMContextImpl::getOperandBundleTags(SmallVectorImpl<StringRef> &Tags) const {
207   Tags.resize(BundleTagCache.size());
208   for (const auto &T : BundleTagCache)
209     Tags[T.second] = T.first();
210 }
211 
212 uint32_t LLVMContextImpl::getOperandBundleTagID(StringRef Tag) const {
213   auto I = BundleTagCache.find(Tag);
214   assert(I != BundleTagCache.end() && "Unknown tag!");
215   return I->second;
216 }
217 
218 SyncScope::ID LLVMContextImpl::getOrInsertSyncScopeID(StringRef SSN) {
219   auto NewSSID = SSC.size();
220   assert(NewSSID < std::numeric_limits<SyncScope::ID>::max() &&
221          "Hit the maximum number of synchronization scopes allowed!");
222   return SSC.insert(std::make_pair(SSN, SyncScope::ID(NewSSID))).first->second;
223 }
224 
225 void LLVMContextImpl::getSyncScopeNames(
226     SmallVectorImpl<StringRef> &SSNs) const {
227   SSNs.resize(SSC.size());
228   for (const auto &SSE : SSC)
229     SSNs[SSE.second] = SSE.first();
230 }
231 
232 /// Singleton instance of the OptBisect class.
233 ///
234 /// This singleton is accessed via the LLVMContext::getOptPassGate() function.
235 /// It provides a mechanism to disable passes and individual optimizations at
236 /// compile time based on a command line option (-opt-bisect-limit) in order to
237 /// perform a bisecting search for optimization-related problems.
238 ///
239 /// Even if multiple LLVMContext objects are created, they will all return the
240 /// same instance of OptBisect in order to provide a single bisect count.  Any
241 /// code that uses the OptBisect object should be serialized when bisection is
242 /// enabled in order to enable a consistent bisect count.
243 static ManagedStatic<OptBisect> OptBisector;
244 
245 OptPassGate &LLVMContextImpl::getOptPassGate() const {
246   if (!OPG)
247     OPG = &(*OptBisector);
248   return *OPG;
249 }
250 
251 void LLVMContextImpl::setOptPassGate(OptPassGate& OPG) {
252   this->OPG = &OPG;
253 }
254