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/CommandLine.h"
19 #include "llvm/Support/ManagedStatic.h"
20 #include <cassert>
21 #include <utility>
22 
23 using namespace llvm;
24 
25 static cl::opt<bool>
26     ForceOpaquePointersCL("force-opaque-pointers",
27                           cl::desc("Force all pointers to be opaque pointers"),
28                           cl::init(false));
29 
30 LLVMContextImpl::LLVMContextImpl(LLVMContext &C)
31     : DiagHandler(std::make_unique<DiagnosticHandler>()),
32       VoidTy(C, Type::VoidTyID), LabelTy(C, Type::LabelTyID),
33       HalfTy(C, Type::HalfTyID), BFloatTy(C, Type::BFloatTyID),
34       FloatTy(C, Type::FloatTyID), DoubleTy(C, Type::DoubleTyID),
35       MetadataTy(C, Type::MetadataTyID), TokenTy(C, Type::TokenTyID),
36       X86_FP80Ty(C, Type::X86_FP80TyID), FP128Ty(C, Type::FP128TyID),
37       PPC_FP128Ty(C, Type::PPC_FP128TyID), X86_MMXTy(C, Type::X86_MMXTyID),
38       X86_AMXTy(C, Type::X86_AMXTyID), Int1Ty(C, 1), Int8Ty(C, 8),
39       Int16Ty(C, 16), Int32Ty(C, 32), Int64Ty(C, 64), Int128Ty(C, 128),
40       ForceOpaquePointers(ForceOpaquePointersCL) {}
41 
42 LLVMContextImpl::~LLVMContextImpl() {
43   // NOTE: We need to delete the contents of OwnedModules, but Module's dtor
44   // will call LLVMContextImpl::removeModule, thus invalidating iterators into
45   // the container. Avoid iterators during this operation:
46   while (!OwnedModules.empty())
47     delete *OwnedModules.begin();
48 
49 #ifndef NDEBUG
50   // Check for metadata references from leaked Values.
51   for (auto &Pair : ValueMetadata)
52     Pair.first->dump();
53   assert(ValueMetadata.empty() && "Values with metadata have been leaked");
54 #endif
55 
56   // Drop references for MDNodes.  Do this before Values get deleted to avoid
57   // unnecessary RAUW when nodes are still unresolved.
58   for (auto *I : DistinctMDNodes) {
59     // We may have DIArgList that were uniqued, and as it has a custom
60     // implementation of dropAllReferences, it needs to be explicitly invoked.
61     if (auto *AL = dyn_cast<DIArgList>(I)) {
62       AL->dropAllReferences();
63       continue;
64     }
65     I->dropAllReferences();
66   }
67 #define HANDLE_MDNODE_LEAF_UNIQUABLE(CLASS)                                    \
68   for (auto *I : CLASS##s)                                                     \
69     I->dropAllReferences();
70 #include "llvm/IR/Metadata.def"
71 
72   // Also drop references that come from the Value bridges.
73   for (auto &Pair : ValuesAsMetadata)
74     Pair.second->dropUsers();
75   for (auto &Pair : MetadataAsValues)
76     Pair.second->dropUse();
77 
78   // Destroy MDNodes.
79   for (MDNode *I : DistinctMDNodes)
80     I->deleteAsSubclass();
81 #define HANDLE_MDNODE_LEAF_UNIQUABLE(CLASS)                                    \
82   for (CLASS * I : CLASS##s)                                                   \
83     delete I;
84 #include "llvm/IR/Metadata.def"
85 
86   // Free the constants.
87   for (auto *I : ExprConstants)
88     I->dropAllReferences();
89   for (auto *I : ArrayConstants)
90     I->dropAllReferences();
91   for (auto *I : StructConstants)
92     I->dropAllReferences();
93   for (auto *I : VectorConstants)
94     I->dropAllReferences();
95   ExprConstants.freeConstants();
96   ArrayConstants.freeConstants();
97   StructConstants.freeConstants();
98   VectorConstants.freeConstants();
99   InlineAsms.freeConstants();
100 
101   CAZConstants.clear();
102   CPNConstants.clear();
103   UVConstants.clear();
104   PVConstants.clear();
105   IntConstants.clear();
106   FPConstants.clear();
107   CDSConstants.clear();
108 
109   // Destroy attribute node lists.
110   for (FoldingSetIterator<AttributeSetNode> I = AttrsSetNodes.begin(),
111          E = AttrsSetNodes.end(); I != E; ) {
112     FoldingSetIterator<AttributeSetNode> Elem = I++;
113     delete &*Elem;
114   }
115 
116   // Destroy MetadataAsValues.
117   {
118     SmallVector<MetadataAsValue *, 8> MDVs;
119     MDVs.reserve(MetadataAsValues.size());
120     for (auto &Pair : MetadataAsValues)
121       MDVs.push_back(Pair.second);
122     MetadataAsValues.clear();
123     for (auto *V : MDVs)
124       delete V;
125   }
126 
127   // Destroy ValuesAsMetadata.
128   for (auto &Pair : ValuesAsMetadata)
129     delete Pair.second;
130 }
131 
132 void LLVMContextImpl::dropTriviallyDeadConstantArrays() {
133   SmallSetVector<ConstantArray *, 4> WorkList;
134 
135   // When ArrayConstants are of substantial size and only a few in them are
136   // dead, starting WorkList with all elements of ArrayConstants can be
137   // wasteful. Instead, starting WorkList with only elements that have empty
138   // uses.
139   for (ConstantArray *C : ArrayConstants)
140     if (C->use_empty())
141       WorkList.insert(C);
142 
143   while (!WorkList.empty()) {
144     ConstantArray *C = WorkList.pop_back_val();
145     if (C->use_empty()) {
146       for (const Use &Op : C->operands()) {
147         if (auto *COp = dyn_cast<ConstantArray>(Op))
148           WorkList.insert(COp);
149       }
150       C->destroyConstant();
151     }
152   }
153 }
154 
155 void Module::dropTriviallyDeadConstantArrays() {
156   Context.pImpl->dropTriviallyDeadConstantArrays();
157 }
158 
159 namespace llvm {
160 
161 /// Make MDOperand transparent for hashing.
162 ///
163 /// This overload of an implementation detail of the hashing library makes
164 /// MDOperand hash to the same value as a \a Metadata pointer.
165 ///
166 /// Note that overloading \a hash_value() as follows:
167 ///
168 /// \code
169 ///     size_t hash_value(const MDOperand &X) { return hash_value(X.get()); }
170 /// \endcode
171 ///
172 /// does not cause MDOperand to be transparent.  In particular, a bare pointer
173 /// doesn't get hashed before it's combined, whereas \a MDOperand would.
174 static const Metadata *get_hashable_data(const MDOperand &X) { return X.get(); }
175 
176 } // end namespace llvm
177 
178 unsigned MDNodeOpsKey::calculateHash(MDNode *N, unsigned Offset) {
179   unsigned Hash = hash_combine_range(N->op_begin() + Offset, N->op_end());
180 #ifndef NDEBUG
181   {
182     SmallVector<Metadata *, 8> MDs(drop_begin(N->operands(), Offset));
183     unsigned RawHash = calculateHash(MDs);
184     assert(Hash == RawHash &&
185            "Expected hash of MDOperand to equal hash of Metadata*");
186   }
187 #endif
188   return Hash;
189 }
190 
191 unsigned MDNodeOpsKey::calculateHash(ArrayRef<Metadata *> Ops) {
192   return hash_combine_range(Ops.begin(), Ops.end());
193 }
194 
195 StringMapEntry<uint32_t> *LLVMContextImpl::getOrInsertBundleTag(StringRef Tag) {
196   uint32_t NewIdx = BundleTagCache.size();
197   return &*(BundleTagCache.insert(std::make_pair(Tag, NewIdx)).first);
198 }
199 
200 void LLVMContextImpl::getOperandBundleTags(SmallVectorImpl<StringRef> &Tags) const {
201   Tags.resize(BundleTagCache.size());
202   for (const auto &T : BundleTagCache)
203     Tags[T.second] = T.first();
204 }
205 
206 uint32_t LLVMContextImpl::getOperandBundleTagID(StringRef Tag) const {
207   auto I = BundleTagCache.find(Tag);
208   assert(I != BundleTagCache.end() && "Unknown tag!");
209   return I->second;
210 }
211 
212 SyncScope::ID LLVMContextImpl::getOrInsertSyncScopeID(StringRef SSN) {
213   auto NewSSID = SSC.size();
214   assert(NewSSID < std::numeric_limits<SyncScope::ID>::max() &&
215          "Hit the maximum number of synchronization scopes allowed!");
216   return SSC.insert(std::make_pair(SSN, SyncScope::ID(NewSSID))).first->second;
217 }
218 
219 void LLVMContextImpl::getSyncScopeNames(
220     SmallVectorImpl<StringRef> &SSNs) const {
221   SSNs.resize(SSC.size());
222   for (const auto &SSE : SSC)
223     SSNs[SSE.second] = SSE.first();
224 }
225 
226 /// Gets the OptPassGate for this LLVMContextImpl, which defaults to the
227 /// singleton OptBisect if not explicitly set.
228 OptPassGate &LLVMContextImpl::getOptPassGate() const {
229   if (!OPG)
230     OPG = &(*OptBisector);
231   return *OPG;
232 }
233 
234 void LLVMContextImpl::setOptPassGate(OptPassGate& OPG) {
235   this->OPG = &OPG;
236 }
237