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 "AttributeImpl.h"
15 #include "llvm/ADT/SetVector.h"
16 #include "llvm/ADT/StringMapEntry.h"
17 #include "llvm/ADT/iterator.h"
18 #include "llvm/ADT/iterator_range.h"
19 #include "llvm/IR/DiagnosticHandler.h"
20 #include "llvm/IR/LLVMRemarkStreamer.h"
21 #include "llvm/IR/Module.h"
22 #include "llvm/IR/OptBisect.h"
23 #include "llvm/IR/Type.h"
24 #include "llvm/IR/Use.h"
25 #include "llvm/IR/User.h"
26 #include "llvm/Remarks/RemarkStreamer.h"
27 #include "llvm/Support/CommandLine.h"
28 #include "llvm/Support/Compiler.h"
29 #include "llvm/Support/ErrorHandling.h"
30 #include "llvm/Support/TypeSize.h"
31 #include <cassert>
32 #include <utility>
33 
34 using namespace llvm;
35 
36 LLVMContextImpl::LLVMContextImpl(LLVMContext &C)
37     : DiagHandler(std::make_unique<DiagnosticHandler>()),
38       VoidTy(C, Type::VoidTyID), LabelTy(C, Type::LabelTyID),
39       HalfTy(C, Type::HalfTyID), BFloatTy(C, Type::BFloatTyID),
40       FloatTy(C, Type::FloatTyID), DoubleTy(C, Type::DoubleTyID),
41       MetadataTy(C, Type::MetadataTyID), TokenTy(C, Type::TokenTyID),
42       X86_FP80Ty(C, Type::X86_FP80TyID), FP128Ty(C, Type::FP128TyID),
43       PPC_FP128Ty(C, Type::PPC_FP128TyID), X86_MMXTy(C, Type::X86_MMXTyID),
44       X86_AMXTy(C, Type::X86_AMXTyID), Int1Ty(C, 1), Int8Ty(C, 8),
45       Int16Ty(C, 16), Int32Ty(C, 32), Int64Ty(C, 64), Int128Ty(C, 128) {}
46 
47 LLVMContextImpl::~LLVMContextImpl() {
48 #ifndef NDEBUG
49   // Check that any variable location records that fell off the end of a block
50   // when it's terminator was removed were eventually replaced. This assertion
51   // firing indicates that DPValues went missing during the lifetime of the
52   // LLVMContext.
53   assert(TrailingDPValues.empty() && "DPValue records in blocks not cleaned");
54 #endif
55 
56   // NOTE: We need to delete the contents of OwnedModules, but Module's dtor
57   // will call LLVMContextImpl::removeModule, thus invalidating iterators into
58   // the container. Avoid iterators during this operation:
59   while (!OwnedModules.empty())
60     delete *OwnedModules.begin();
61 
62 #ifndef NDEBUG
63   // Check for metadata references from leaked Values.
64   for (auto &Pair : ValueMetadata)
65     Pair.first->dump();
66   assert(ValueMetadata.empty() && "Values with metadata have been leaked");
67 #endif
68 
69   // Drop references for MDNodes.  Do this before Values get deleted to avoid
70   // unnecessary RAUW when nodes are still unresolved.
71   for (auto *I : DistinctMDNodes)
72     I->dropAllReferences();
73 #define HANDLE_MDNODE_LEAF_UNIQUABLE(CLASS)                                    \
74   for (auto *I : CLASS##s)                                                     \
75     I->dropAllReferences();
76 #include "llvm/IR/Metadata.def"
77 
78   // Also drop references that come from the Value bridges.
79   for (auto &Pair : ValuesAsMetadata)
80     Pair.second->dropUsers();
81   for (auto &Pair : MetadataAsValues)
82     Pair.second->dropUse();
83   // Do not untrack ValueAsMetadata references for DIArgLists, as they have
84   // already been more efficiently untracked above.
85   for (DIArgList *AL : DIArgLists) {
86     AL->dropAllReferences(/* Untrack */ false);
87     delete AL;
88   }
89   DIArgLists.clear();
90 
91   // Destroy MDNodes.
92   for (MDNode *I : DistinctMDNodes)
93     I->deleteAsSubclass();
94 #define HANDLE_MDNODE_LEAF_UNIQUABLE(CLASS)                                    \
95   for (CLASS * I : CLASS##s)                                                   \
96     delete I;
97 #include "llvm/IR/Metadata.def"
98 
99   // Free the constants.
100   for (auto *I : ExprConstants)
101     I->dropAllReferences();
102   for (auto *I : ArrayConstants)
103     I->dropAllReferences();
104   for (auto *I : StructConstants)
105     I->dropAllReferences();
106   for (auto *I : VectorConstants)
107     I->dropAllReferences();
108   ExprConstants.freeConstants();
109   ArrayConstants.freeConstants();
110   StructConstants.freeConstants();
111   VectorConstants.freeConstants();
112   InlineAsms.freeConstants();
113 
114   CAZConstants.clear();
115   CPNConstants.clear();
116   CTNConstants.clear();
117   UVConstants.clear();
118   PVConstants.clear();
119   IntZeroConstants.clear();
120   IntOneConstants.clear();
121   IntConstants.clear();
122   FPConstants.clear();
123   CDSConstants.clear();
124 
125   // Destroy attribute node lists.
126   for (FoldingSetIterator<AttributeSetNode> I = AttrsSetNodes.begin(),
127          E = AttrsSetNodes.end(); I != E; ) {
128     FoldingSetIterator<AttributeSetNode> Elem = I++;
129     delete &*Elem;
130   }
131 
132   // Destroy MetadataAsValues.
133   {
134     SmallVector<MetadataAsValue *, 8> MDVs;
135     MDVs.reserve(MetadataAsValues.size());
136     for (auto &Pair : MetadataAsValues)
137       MDVs.push_back(Pair.second);
138     MetadataAsValues.clear();
139     for (auto *V : MDVs)
140       delete V;
141   }
142 
143   // Destroy ValuesAsMetadata.
144   for (auto &Pair : ValuesAsMetadata)
145     delete Pair.second;
146 }
147 
148 void LLVMContextImpl::dropTriviallyDeadConstantArrays() {
149   SmallSetVector<ConstantArray *, 4> WorkList;
150 
151   // When ArrayConstants are of substantial size and only a few in them are
152   // dead, starting WorkList with all elements of ArrayConstants can be
153   // wasteful. Instead, starting WorkList with only elements that have empty
154   // uses.
155   for (ConstantArray *C : ArrayConstants)
156     if (C->use_empty())
157       WorkList.insert(C);
158 
159   while (!WorkList.empty()) {
160     ConstantArray *C = WorkList.pop_back_val();
161     if (C->use_empty()) {
162       for (const Use &Op : C->operands()) {
163         if (auto *COp = dyn_cast<ConstantArray>(Op))
164           WorkList.insert(COp);
165       }
166       C->destroyConstant();
167     }
168   }
169 }
170 
171 void Module::dropTriviallyDeadConstantArrays() {
172   Context.pImpl->dropTriviallyDeadConstantArrays();
173 }
174 
175 namespace llvm {
176 
177 /// Make MDOperand transparent for hashing.
178 ///
179 /// This overload of an implementation detail of the hashing library makes
180 /// MDOperand hash to the same value as a \a Metadata pointer.
181 ///
182 /// Note that overloading \a hash_value() as follows:
183 ///
184 /// \code
185 ///     size_t hash_value(const MDOperand &X) { return hash_value(X.get()); }
186 /// \endcode
187 ///
188 /// does not cause MDOperand to be transparent.  In particular, a bare pointer
189 /// doesn't get hashed before it's combined, whereas \a MDOperand would.
190 static const Metadata *get_hashable_data(const MDOperand &X) { return X.get(); }
191 
192 } // end namespace llvm
193 
194 unsigned MDNodeOpsKey::calculateHash(MDNode *N, unsigned Offset) {
195   unsigned Hash = hash_combine_range(N->op_begin() + Offset, N->op_end());
196 #ifndef NDEBUG
197   {
198     SmallVector<Metadata *, 8> MDs(drop_begin(N->operands(), Offset));
199     unsigned RawHash = calculateHash(MDs);
200     assert(Hash == RawHash &&
201            "Expected hash of MDOperand to equal hash of Metadata*");
202   }
203 #endif
204   return Hash;
205 }
206 
207 unsigned MDNodeOpsKey::calculateHash(ArrayRef<Metadata *> Ops) {
208   return hash_combine_range(Ops.begin(), Ops.end());
209 }
210 
211 StringMapEntry<uint32_t> *LLVMContextImpl::getOrInsertBundleTag(StringRef Tag) {
212   uint32_t NewIdx = BundleTagCache.size();
213   return &*(BundleTagCache.insert(std::make_pair(Tag, NewIdx)).first);
214 }
215 
216 void LLVMContextImpl::getOperandBundleTags(SmallVectorImpl<StringRef> &Tags) const {
217   Tags.resize(BundleTagCache.size());
218   for (const auto &T : BundleTagCache)
219     Tags[T.second] = T.first();
220 }
221 
222 uint32_t LLVMContextImpl::getOperandBundleTagID(StringRef Tag) const {
223   auto I = BundleTagCache.find(Tag);
224   assert(I != BundleTagCache.end() && "Unknown tag!");
225   return I->second;
226 }
227 
228 SyncScope::ID LLVMContextImpl::getOrInsertSyncScopeID(StringRef SSN) {
229   auto NewSSID = SSC.size();
230   assert(NewSSID < std::numeric_limits<SyncScope::ID>::max() &&
231          "Hit the maximum number of synchronization scopes allowed!");
232   return SSC.insert(std::make_pair(SSN, SyncScope::ID(NewSSID))).first->second;
233 }
234 
235 void LLVMContextImpl::getSyncScopeNames(
236     SmallVectorImpl<StringRef> &SSNs) const {
237   SSNs.resize(SSC.size());
238   for (const auto &SSE : SSC)
239     SSNs[SSE.second] = SSE.first();
240 }
241 
242 /// Gets the OptPassGate for this LLVMContextImpl, which defaults to the
243 /// singleton OptBisect if not explicitly set.
244 OptPassGate &LLVMContextImpl::getOptPassGate() const {
245   if (!OPG)
246     OPG = &getGlobalPassGate();
247   return *OPG;
248 }
249 
250 void LLVMContextImpl::setOptPassGate(OptPassGate& OPG) {
251   this->OPG = &OPG;
252 }
253