1 //===---- llvm/MDBuilder.cpp - Builder for LLVM metadata ------------------===//
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 defines the MDBuilder class, which is used as a convenient way to
10 // create LLVM metadata with a consistent and simplified interface.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/IR/MDBuilder.h"
15 #include "llvm/IR/Constants.h"
16 #include "llvm/IR/Function.h"
17 #include "llvm/IR/Metadata.h"
18 using namespace llvm;
19 
20 MDString *MDBuilder::createString(StringRef Str) {
21   return MDString::get(Context, Str);
22 }
23 
24 ConstantAsMetadata *MDBuilder::createConstant(Constant *C) {
25   return ConstantAsMetadata::get(C);
26 }
27 
28 MDNode *MDBuilder::createFPMath(float Accuracy) {
29   if (Accuracy == 0.0)
30     return nullptr;
31   assert(Accuracy > 0.0 && "Invalid fpmath accuracy!");
32   auto *Op =
33       createConstant(ConstantFP::get(Type::getFloatTy(Context), Accuracy));
34   return MDNode::get(Context, Op);
35 }
36 
37 MDNode *MDBuilder::createBranchWeights(uint32_t TrueWeight,
38                                        uint32_t FalseWeight) {
39   return createBranchWeights({TrueWeight, FalseWeight});
40 }
41 
42 MDNode *MDBuilder::createBranchWeights(ArrayRef<uint32_t> Weights) {
43   assert(Weights.size() >= 1 && "Need at least one branch weights!");
44 
45   SmallVector<Metadata *, 4> Vals(Weights.size() + 1);
46   Vals[0] = createString("branch_weights");
47 
48   Type *Int32Ty = Type::getInt32Ty(Context);
49   for (unsigned i = 0, e = Weights.size(); i != e; ++i)
50     Vals[i + 1] = createConstant(ConstantInt::get(Int32Ty, Weights[i]));
51 
52   return MDNode::get(Context, Vals);
53 }
54 
55 MDNode *MDBuilder::createUnpredictable() {
56   return MDNode::get(Context, std::nullopt);
57 }
58 
59 MDNode *MDBuilder::createFunctionEntryCount(
60     uint64_t Count, bool Synthetic,
61     const DenseSet<GlobalValue::GUID> *Imports) {
62   Type *Int64Ty = Type::getInt64Ty(Context);
63   SmallVector<Metadata *, 8> Ops;
64   if (Synthetic)
65     Ops.push_back(createString("synthetic_function_entry_count"));
66   else
67     Ops.push_back(createString("function_entry_count"));
68   Ops.push_back(createConstant(ConstantInt::get(Int64Ty, Count)));
69   if (Imports) {
70     SmallVector<GlobalValue::GUID, 2> OrderID(Imports->begin(), Imports->end());
71     llvm::sort(OrderID);
72     for (auto ID : OrderID)
73       Ops.push_back(createConstant(ConstantInt::get(Int64Ty, ID)));
74   }
75   return MDNode::get(Context, Ops);
76 }
77 
78 MDNode *MDBuilder::createFunctionSectionPrefix(StringRef Prefix) {
79   return MDNode::get(Context,
80                      {createString("function_section_prefix"),
81                       createString(Prefix)});
82 }
83 
84 MDNode *MDBuilder::createRange(const APInt &Lo, const APInt &Hi) {
85   assert(Lo.getBitWidth() == Hi.getBitWidth() && "Mismatched bitwidths!");
86 
87   Type *Ty = IntegerType::get(Context, Lo.getBitWidth());
88   return createRange(ConstantInt::get(Ty, Lo), ConstantInt::get(Ty, Hi));
89 }
90 
91 MDNode *MDBuilder::createRange(Constant *Lo, Constant *Hi) {
92   // If the range is everything then it is useless.
93   if (Hi == Lo)
94     return nullptr;
95 
96   // Return the range [Lo, Hi).
97   return MDNode::get(Context, {createConstant(Lo), createConstant(Hi)});
98 }
99 
100 MDNode *MDBuilder::createCallees(ArrayRef<Function *> Callees) {
101   SmallVector<Metadata *, 4> Ops;
102   for (Function *F : Callees)
103     Ops.push_back(createConstant(F));
104   return MDNode::get(Context, Ops);
105 }
106 
107 MDNode *MDBuilder::createCallbackEncoding(unsigned CalleeArgNo,
108                                           ArrayRef<int> Arguments,
109                                           bool VarArgArePassed) {
110   SmallVector<Metadata *, 4> Ops;
111 
112   Type *Int64 = Type::getInt64Ty(Context);
113   Ops.push_back(createConstant(ConstantInt::get(Int64, CalleeArgNo)));
114 
115   for (int ArgNo : Arguments)
116     Ops.push_back(createConstant(ConstantInt::get(Int64, ArgNo, true)));
117 
118   Type *Int1 = Type::getInt1Ty(Context);
119   Ops.push_back(createConstant(ConstantInt::get(Int1, VarArgArePassed)));
120 
121   return MDNode::get(Context, Ops);
122 }
123 
124 MDNode *MDBuilder::mergeCallbackEncodings(MDNode *ExistingCallbacks,
125                                           MDNode *NewCB) {
126   if (!ExistingCallbacks)
127     return MDNode::get(Context, {NewCB});
128 
129   auto *NewCBCalleeIdxAsCM = cast<ConstantAsMetadata>(NewCB->getOperand(0));
130   uint64_t NewCBCalleeIdx =
131       cast<ConstantInt>(NewCBCalleeIdxAsCM->getValue())->getZExtValue();
132   (void)NewCBCalleeIdx;
133 
134   SmallVector<Metadata *, 4> Ops;
135   unsigned NumExistingOps = ExistingCallbacks->getNumOperands();
136   Ops.resize(NumExistingOps + 1);
137 
138   for (unsigned u = 0; u < NumExistingOps; u++) {
139     Ops[u] = ExistingCallbacks->getOperand(u);
140 
141     auto *OldCBCalleeIdxAsCM = cast<ConstantAsMetadata>(Ops[u]);
142     uint64_t OldCBCalleeIdx =
143       cast<ConstantInt>(OldCBCalleeIdxAsCM->getValue())->getZExtValue();
144     (void)OldCBCalleeIdx;
145     assert(NewCBCalleeIdx != OldCBCalleeIdx &&
146            "Cannot map a callback callee index twice!");
147   }
148 
149   Ops[NumExistingOps] = NewCB;
150   return MDNode::get(Context, Ops);
151 }
152 
153 MDNode *MDBuilder::createRTTIPointerPrologue(Constant *PrologueSig,
154                                              Constant *RTTI) {
155   SmallVector<Metadata *, 4> Ops;
156   Ops.push_back(createConstant(PrologueSig));
157   Ops.push_back(createConstant(RTTI));
158   return MDNode::get(Context, Ops);
159 }
160 
161 MDNode *MDBuilder::createPCSections(ArrayRef<PCSection> Sections) {
162   SmallVector<Metadata *, 2> Ops;
163 
164   for (const auto &Entry : Sections) {
165     const StringRef &Sec = Entry.first;
166     Ops.push_back(createString(Sec));
167 
168     // If auxiliary data for this section exists, append it.
169     const SmallVector<Constant *> &AuxConsts = Entry.second;
170     if (!AuxConsts.empty()) {
171       SmallVector<Metadata *, 1> AuxMDs;
172       AuxMDs.reserve(AuxConsts.size());
173       for (Constant *C : AuxConsts)
174         AuxMDs.push_back(createConstant(C));
175       Ops.push_back(MDNode::get(Context, AuxMDs));
176     }
177   }
178 
179   return MDNode::get(Context, Ops);
180 }
181 
182 MDNode *MDBuilder::createAnonymousAARoot(StringRef Name, MDNode *Extra) {
183   SmallVector<Metadata *, 3> Args(1, nullptr);
184   if (Extra)
185     Args.push_back(Extra);
186   if (!Name.empty())
187     Args.push_back(createString(Name));
188   MDNode *Root = MDNode::getDistinct(Context, Args);
189 
190   // At this point we have
191   //   !0 = distinct !{null} <- root
192   // Replace the reserved operand with the root node itself.
193   Root->replaceOperandWith(0, Root);
194 
195   // We now have
196   //   !0 = distinct !{!0} <- root
197   return Root;
198 }
199 
200 MDNode *MDBuilder::createTBAARoot(StringRef Name) {
201   return MDNode::get(Context, createString(Name));
202 }
203 
204 /// Return metadata for a non-root TBAA node with the given name,
205 /// parent in the TBAA tree, and value for 'pointsToConstantMemory'.
206 MDNode *MDBuilder::createTBAANode(StringRef Name, MDNode *Parent,
207                                   bool isConstant) {
208   if (isConstant) {
209     Constant *Flags = ConstantInt::get(Type::getInt64Ty(Context), 1);
210     return MDNode::get(Context,
211                        {createString(Name), Parent, createConstant(Flags)});
212   }
213   return MDNode::get(Context, {createString(Name), Parent});
214 }
215 
216 MDNode *MDBuilder::createAliasScopeDomain(StringRef Name) {
217   return MDNode::get(Context, createString(Name));
218 }
219 
220 MDNode *MDBuilder::createAliasScope(StringRef Name, MDNode *Domain) {
221   return MDNode::get(Context, {createString(Name), Domain});
222 }
223 
224 /// Return metadata for a tbaa.struct node with the given
225 /// struct field descriptions.
226 MDNode *MDBuilder::createTBAAStructNode(ArrayRef<TBAAStructField> Fields) {
227   SmallVector<Metadata *, 4> Vals(Fields.size() * 3);
228   Type *Int64 = Type::getInt64Ty(Context);
229   for (unsigned i = 0, e = Fields.size(); i != e; ++i) {
230     Vals[i * 3 + 0] = createConstant(ConstantInt::get(Int64, Fields[i].Offset));
231     Vals[i * 3 + 1] = createConstant(ConstantInt::get(Int64, Fields[i].Size));
232     Vals[i * 3 + 2] = Fields[i].Type;
233   }
234   return MDNode::get(Context, Vals);
235 }
236 
237 /// Return metadata for a TBAA struct node in the type DAG
238 /// with the given name, a list of pairs (offset, field type in the type DAG).
239 MDNode *MDBuilder::createTBAAStructTypeNode(
240     StringRef Name, ArrayRef<std::pair<MDNode *, uint64_t>> Fields) {
241   SmallVector<Metadata *, 4> Ops(Fields.size() * 2 + 1);
242   Type *Int64 = Type::getInt64Ty(Context);
243   Ops[0] = createString(Name);
244   for (unsigned i = 0, e = Fields.size(); i != e; ++i) {
245     Ops[i * 2 + 1] = Fields[i].first;
246     Ops[i * 2 + 2] = createConstant(ConstantInt::get(Int64, Fields[i].second));
247   }
248   return MDNode::get(Context, Ops);
249 }
250 
251 /// Return metadata for a TBAA scalar type node with the
252 /// given name, an offset and a parent in the TBAA type DAG.
253 MDNode *MDBuilder::createTBAAScalarTypeNode(StringRef Name, MDNode *Parent,
254                                             uint64_t Offset) {
255   ConstantInt *Off = ConstantInt::get(Type::getInt64Ty(Context), Offset);
256   return MDNode::get(Context,
257                      {createString(Name), Parent, createConstant(Off)});
258 }
259 
260 /// Return metadata for a TBAA tag node with the given
261 /// base type, access type and offset relative to the base type.
262 MDNode *MDBuilder::createTBAAStructTagNode(MDNode *BaseType, MDNode *AccessType,
263                                            uint64_t Offset, bool IsConstant) {
264   IntegerType *Int64 = Type::getInt64Ty(Context);
265   ConstantInt *Off = ConstantInt::get(Int64, Offset);
266   if (IsConstant) {
267     return MDNode::get(Context, {BaseType, AccessType, createConstant(Off),
268                                  createConstant(ConstantInt::get(Int64, 1))});
269   }
270   return MDNode::get(Context, {BaseType, AccessType, createConstant(Off)});
271 }
272 
273 MDNode *MDBuilder::createTBAATypeNode(MDNode *Parent, uint64_t Size,
274                                       Metadata *Id,
275                                       ArrayRef<TBAAStructField> Fields) {
276   SmallVector<Metadata *, 4> Ops(3 + Fields.size() * 3);
277   Type *Int64 = Type::getInt64Ty(Context);
278   Ops[0] = Parent;
279   Ops[1] = createConstant(ConstantInt::get(Int64, Size));
280   Ops[2] = Id;
281   for (unsigned I = 0, E = Fields.size(); I != E; ++I) {
282     Ops[I * 3 + 3] = Fields[I].Type;
283     Ops[I * 3 + 4] = createConstant(ConstantInt::get(Int64, Fields[I].Offset));
284     Ops[I * 3 + 5] = createConstant(ConstantInt::get(Int64, Fields[I].Size));
285   }
286   return MDNode::get(Context, Ops);
287 }
288 
289 MDNode *MDBuilder::createTBAAAccessTag(MDNode *BaseType, MDNode *AccessType,
290                                        uint64_t Offset, uint64_t Size,
291                                        bool IsImmutable) {
292   IntegerType *Int64 = Type::getInt64Ty(Context);
293   auto *OffsetNode = createConstant(ConstantInt::get(Int64, Offset));
294   auto *SizeNode = createConstant(ConstantInt::get(Int64, Size));
295   if (IsImmutable) {
296     auto *ImmutabilityFlagNode = createConstant(ConstantInt::get(Int64, 1));
297     return MDNode::get(Context, {BaseType, AccessType, OffsetNode, SizeNode,
298                                  ImmutabilityFlagNode});
299   }
300   return MDNode::get(Context, {BaseType, AccessType, OffsetNode, SizeNode});
301 }
302 
303 MDNode *MDBuilder::createMutableTBAAAccessTag(MDNode *Tag) {
304   MDNode *BaseType = cast<MDNode>(Tag->getOperand(0));
305   MDNode *AccessType = cast<MDNode>(Tag->getOperand(1));
306   Metadata *OffsetNode = Tag->getOperand(2);
307   uint64_t Offset = mdconst::extract<ConstantInt>(OffsetNode)->getZExtValue();
308 
309   bool NewFormat = isa<MDNode>(AccessType->getOperand(0));
310 
311   // See if the tag is already mutable.
312   unsigned ImmutabilityFlagOp = NewFormat ? 4 : 3;
313   if (Tag->getNumOperands() <= ImmutabilityFlagOp)
314     return Tag;
315 
316   // If Tag is already mutable then return it.
317   Metadata *ImmutabilityFlagNode = Tag->getOperand(ImmutabilityFlagOp);
318   if (!mdconst::extract<ConstantInt>(ImmutabilityFlagNode)->getValue())
319     return Tag;
320 
321   // Otherwise, create another node.
322   if (!NewFormat)
323     return createTBAAStructTagNode(BaseType, AccessType, Offset);
324 
325   Metadata *SizeNode = Tag->getOperand(3);
326   uint64_t Size = mdconst::extract<ConstantInt>(SizeNode)->getZExtValue();
327   return createTBAAAccessTag(BaseType, AccessType, Offset, Size);
328 }
329 
330 MDNode *MDBuilder::createIrrLoopHeaderWeight(uint64_t Weight) {
331   Metadata *Vals[] = {
332     createString("loop_header_weight"),
333     createConstant(ConstantInt::get(Type::getInt64Ty(Context), Weight)),
334   };
335   return MDNode::get(Context, Vals);
336 }
337 
338 MDNode *MDBuilder::createPseudoProbeDesc(uint64_t GUID, uint64_t Hash,
339                                          StringRef FName) {
340   auto *Int64Ty = Type::getInt64Ty(Context);
341   SmallVector<Metadata *, 3> Ops(3);
342   Ops[0] = createConstant(ConstantInt::get(Int64Ty, GUID));
343   Ops[1] = createConstant(ConstantInt::get(Int64Ty, Hash));
344   Ops[2] = createString(FName);
345   return MDNode::get(Context, Ops);
346 }
347 
348 MDNode *
349 MDBuilder::createLLVMStats(ArrayRef<std::pair<StringRef, uint64_t>> LLVMStats) {
350   auto *Int64Ty = Type::getInt64Ty(Context);
351   SmallVector<Metadata *, 4> Ops(LLVMStats.size() * 2);
352   for (size_t I = 0; I < LLVMStats.size(); I++) {
353     Ops[I * 2] = createString(LLVMStats[I].first);
354     Ops[I * 2 + 1] =
355         createConstant(ConstantInt::get(Int64Ty, LLVMStats[I].second));
356   }
357   return MDNode::get(Context, Ops);
358 }
359