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, None);
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::createAnonymousAARoot(StringRef Name, MDNode *Extra) {
154   SmallVector<Metadata *, 3> Args(1, nullptr);
155   if (Extra)
156     Args.push_back(Extra);
157   if (!Name.empty())
158     Args.push_back(createString(Name));
159   MDNode *Root = MDNode::getDistinct(Context, Args);
160 
161   // At this point we have
162   //   !0 = distinct !{null} <- root
163   // Replace the reserved operand with the root node itself.
164   Root->replaceOperandWith(0, Root);
165 
166   // We now have
167   //   !0 = distinct !{!0} <- root
168   return Root;
169 }
170 
171 MDNode *MDBuilder::createTBAARoot(StringRef Name) {
172   return MDNode::get(Context, createString(Name));
173 }
174 
175 /// Return metadata for a non-root TBAA node with the given name,
176 /// parent in the TBAA tree, and value for 'pointsToConstantMemory'.
177 MDNode *MDBuilder::createTBAANode(StringRef Name, MDNode *Parent,
178                                   bool isConstant) {
179   if (isConstant) {
180     Constant *Flags = ConstantInt::get(Type::getInt64Ty(Context), 1);
181     return MDNode::get(Context,
182                        {createString(Name), Parent, createConstant(Flags)});
183   }
184   return MDNode::get(Context, {createString(Name), Parent});
185 }
186 
187 MDNode *MDBuilder::createAliasScopeDomain(StringRef Name) {
188   return MDNode::get(Context, createString(Name));
189 }
190 
191 MDNode *MDBuilder::createAliasScope(StringRef Name, MDNode *Domain) {
192   return MDNode::get(Context, {createString(Name), Domain});
193 }
194 
195 /// Return metadata for a tbaa.struct node with the given
196 /// struct field descriptions.
197 MDNode *MDBuilder::createTBAAStructNode(ArrayRef<TBAAStructField> Fields) {
198   SmallVector<Metadata *, 4> Vals(Fields.size() * 3);
199   Type *Int64 = Type::getInt64Ty(Context);
200   for (unsigned i = 0, e = Fields.size(); i != e; ++i) {
201     Vals[i * 3 + 0] = createConstant(ConstantInt::get(Int64, Fields[i].Offset));
202     Vals[i * 3 + 1] = createConstant(ConstantInt::get(Int64, Fields[i].Size));
203     Vals[i * 3 + 2] = Fields[i].Type;
204   }
205   return MDNode::get(Context, Vals);
206 }
207 
208 /// Return metadata for a TBAA struct node in the type DAG
209 /// with the given name, a list of pairs (offset, field type in the type DAG).
210 MDNode *MDBuilder::createTBAAStructTypeNode(
211     StringRef Name, ArrayRef<std::pair<MDNode *, uint64_t>> Fields) {
212   SmallVector<Metadata *, 4> Ops(Fields.size() * 2 + 1);
213   Type *Int64 = Type::getInt64Ty(Context);
214   Ops[0] = createString(Name);
215   for (unsigned i = 0, e = Fields.size(); i != e; ++i) {
216     Ops[i * 2 + 1] = Fields[i].first;
217     Ops[i * 2 + 2] = createConstant(ConstantInt::get(Int64, Fields[i].second));
218   }
219   return MDNode::get(Context, Ops);
220 }
221 
222 /// Return metadata for a TBAA scalar type node with the
223 /// given name, an offset and a parent in the TBAA type DAG.
224 MDNode *MDBuilder::createTBAAScalarTypeNode(StringRef Name, MDNode *Parent,
225                                             uint64_t Offset) {
226   ConstantInt *Off = ConstantInt::get(Type::getInt64Ty(Context), Offset);
227   return MDNode::get(Context,
228                      {createString(Name), Parent, createConstant(Off)});
229 }
230 
231 /// Return metadata for a TBAA tag node with the given
232 /// base type, access type and offset relative to the base type.
233 MDNode *MDBuilder::createTBAAStructTagNode(MDNode *BaseType, MDNode *AccessType,
234                                            uint64_t Offset, bool IsConstant) {
235   IntegerType *Int64 = Type::getInt64Ty(Context);
236   ConstantInt *Off = ConstantInt::get(Int64, Offset);
237   if (IsConstant) {
238     return MDNode::get(Context, {BaseType, AccessType, createConstant(Off),
239                                  createConstant(ConstantInt::get(Int64, 1))});
240   }
241   return MDNode::get(Context, {BaseType, AccessType, createConstant(Off)});
242 }
243 
244 MDNode *MDBuilder::createTBAATypeNode(MDNode *Parent, uint64_t Size,
245                                       Metadata *Id,
246                                       ArrayRef<TBAAStructField> Fields) {
247   SmallVector<Metadata *, 4> Ops(3 + Fields.size() * 3);
248   Type *Int64 = Type::getInt64Ty(Context);
249   Ops[0] = Parent;
250   Ops[1] = createConstant(ConstantInt::get(Int64, Size));
251   Ops[2] = Id;
252   for (unsigned I = 0, E = Fields.size(); I != E; ++I) {
253     Ops[I * 3 + 3] = Fields[I].Type;
254     Ops[I * 3 + 4] = createConstant(ConstantInt::get(Int64, Fields[I].Offset));
255     Ops[I * 3 + 5] = createConstant(ConstantInt::get(Int64, Fields[I].Size));
256   }
257   return MDNode::get(Context, Ops);
258 }
259 
260 MDNode *MDBuilder::createTBAAAccessTag(MDNode *BaseType, MDNode *AccessType,
261                                        uint64_t Offset, uint64_t Size,
262                                        bool IsImmutable) {
263   IntegerType *Int64 = Type::getInt64Ty(Context);
264   auto *OffsetNode = createConstant(ConstantInt::get(Int64, Offset));
265   auto *SizeNode = createConstant(ConstantInt::get(Int64, Size));
266   if (IsImmutable) {
267     auto *ImmutabilityFlagNode = createConstant(ConstantInt::get(Int64, 1));
268     return MDNode::get(Context, {BaseType, AccessType, OffsetNode, SizeNode,
269                                  ImmutabilityFlagNode});
270   }
271   return MDNode::get(Context, {BaseType, AccessType, OffsetNode, SizeNode});
272 }
273 
274 MDNode *MDBuilder::createMutableTBAAAccessTag(MDNode *Tag) {
275   MDNode *BaseType = cast<MDNode>(Tag->getOperand(0));
276   MDNode *AccessType = cast<MDNode>(Tag->getOperand(1));
277   Metadata *OffsetNode = Tag->getOperand(2);
278   uint64_t Offset = mdconst::extract<ConstantInt>(OffsetNode)->getZExtValue();
279 
280   bool NewFormat = isa<MDNode>(AccessType->getOperand(0));
281 
282   // See if the tag is already mutable.
283   unsigned ImmutabilityFlagOp = NewFormat ? 4 : 3;
284   if (Tag->getNumOperands() <= ImmutabilityFlagOp)
285     return Tag;
286 
287   // If Tag is already mutable then return it.
288   Metadata *ImmutabilityFlagNode = Tag->getOperand(ImmutabilityFlagOp);
289   if (!mdconst::extract<ConstantInt>(ImmutabilityFlagNode)->getValue())
290     return Tag;
291 
292   // Otherwise, create another node.
293   if (!NewFormat)
294     return createTBAAStructTagNode(BaseType, AccessType, Offset);
295 
296   Metadata *SizeNode = Tag->getOperand(3);
297   uint64_t Size = mdconst::extract<ConstantInt>(SizeNode)->getZExtValue();
298   return createTBAAAccessTag(BaseType, AccessType, Offset, Size);
299 }
300 
301 MDNode *MDBuilder::createIrrLoopHeaderWeight(uint64_t Weight) {
302   Metadata *Vals[] = {
303     createString("loop_header_weight"),
304     createConstant(ConstantInt::get(Type::getInt64Ty(Context), Weight)),
305   };
306   return MDNode::get(Context, Vals);
307 }
308 
309 MDNode *MDBuilder::createPseudoProbeDesc(uint64_t GUID, uint64_t Hash,
310                                          Function *F) {
311   auto *Int64Ty = Type::getInt64Ty(Context);
312   SmallVector<Metadata *, 3> Ops(3);
313   Ops[0] = createConstant(ConstantInt::get(Int64Ty, GUID));
314   Ops[1] = createConstant(ConstantInt::get(Int64Ty, Hash));
315   Ops[2] = createString(F->getName());
316   return MDNode::get(Context, Ops);
317 }
318