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     std::stable_sort(OrderID.begin(), OrderID.end(),
72       [] (GlobalValue::GUID A, GlobalValue::GUID B) {
73         return A < B;});
74     for (auto ID : OrderID)
75       Ops.push_back(createConstant(ConstantInt::get(Int64Ty, ID)));
76   }
77   return MDNode::get(Context, Ops);
78 }
79 
80 MDNode *MDBuilder::createFunctionSectionPrefix(StringRef Prefix) {
81   return MDNode::get(Context,
82                      {createString("function_section_prefix"),
83                       createString(Prefix)});
84 }
85 
86 MDNode *MDBuilder::createRange(const APInt &Lo, const APInt &Hi) {
87   assert(Lo.getBitWidth() == Hi.getBitWidth() && "Mismatched bitwidths!");
88 
89   Type *Ty = IntegerType::get(Context, Lo.getBitWidth());
90   return createRange(ConstantInt::get(Ty, Lo), ConstantInt::get(Ty, Hi));
91 }
92 
93 MDNode *MDBuilder::createRange(Constant *Lo, Constant *Hi) {
94   // If the range is everything then it is useless.
95   if (Hi == Lo)
96     return nullptr;
97 
98   // Return the range [Lo, Hi).
99   return MDNode::get(Context, {createConstant(Lo), createConstant(Hi)});
100 }
101 
102 MDNode *MDBuilder::createCallees(ArrayRef<Function *> Callees) {
103   SmallVector<Metadata *, 4> Ops;
104   for (Function *F : Callees)
105     Ops.push_back(createConstant(F));
106   return MDNode::get(Context, Ops);
107 }
108 
109 MDNode *MDBuilder::createCallbackEncoding(unsigned CalleeArgNo,
110                                           ArrayRef<int> Arguments,
111                                           bool VarArgArePassed) {
112   SmallVector<Metadata *, 4> Ops;
113 
114   Type *Int64 = Type::getInt64Ty(Context);
115   Ops.push_back(createConstant(ConstantInt::get(Int64, CalleeArgNo)));
116 
117   for (int ArgNo : Arguments)
118     Ops.push_back(createConstant(ConstantInt::get(Int64, ArgNo, true)));
119 
120   Type *Int1 = Type::getInt1Ty(Context);
121   Ops.push_back(createConstant(ConstantInt::get(Int1, VarArgArePassed)));
122 
123   return MDNode::get(Context, Ops);
124 }
125 
126 MDNode *MDBuilder::mergeCallbackEncodings(MDNode *ExistingCallbacks,
127                                           MDNode *NewCB) {
128   if (!ExistingCallbacks)
129     return MDNode::get(Context, {NewCB});
130 
131   auto *NewCBCalleeIdxAsCM = cast<ConstantAsMetadata>(NewCB->getOperand(0));
132   uint64_t NewCBCalleeIdx =
133       cast<ConstantInt>(NewCBCalleeIdxAsCM->getValue())->getZExtValue();
134   (void)NewCBCalleeIdx;
135 
136   SmallVector<Metadata *, 4> Ops;
137   unsigned NumExistingOps = ExistingCallbacks->getNumOperands();
138   Ops.resize(NumExistingOps + 1);
139 
140   for (unsigned u = 0; u < NumExistingOps; u++) {
141     Ops[u] = ExistingCallbacks->getOperand(u);
142 
143     auto *OldCBCalleeIdxAsCM = cast<ConstantAsMetadata>(Ops[u]);
144     uint64_t OldCBCalleeIdx =
145       cast<ConstantInt>(OldCBCalleeIdxAsCM->getValue())->getZExtValue();
146     (void)OldCBCalleeIdx;
147     assert(NewCBCalleeIdx != OldCBCalleeIdx &&
148            "Cannot map a callback callee index twice!");
149   }
150 
151   Ops[NumExistingOps] = NewCB;
152   return MDNode::get(Context, Ops);
153 }
154 
155 MDNode *MDBuilder::createAnonymousAARoot(StringRef Name, MDNode *Extra) {
156   // To ensure uniqueness the root node is self-referential.
157   auto Dummy = MDNode::getTemporary(Context, None);
158 
159   SmallVector<Metadata *, 3> Args(1, Dummy.get());
160   if (Extra)
161     Args.push_back(Extra);
162   if (!Name.empty())
163     Args.push_back(createString(Name));
164   MDNode *Root = MDNode::get(Context, Args);
165 
166   // At this point we have
167   //   !0 = metadata !{}            <- dummy
168   //   !1 = metadata !{metadata !0} <- root
169   // Replace the dummy operand with the root node itself and delete the dummy.
170   Root->replaceOperandWith(0, Root);
171 
172   // We now have
173   //   !1 = metadata !{metadata !1} <- self-referential root
174   return Root;
175 }
176 
177 MDNode *MDBuilder::createTBAARoot(StringRef Name) {
178   return MDNode::get(Context, createString(Name));
179 }
180 
181 /// Return metadata for a non-root TBAA node with the given name,
182 /// parent in the TBAA tree, and value for 'pointsToConstantMemory'.
183 MDNode *MDBuilder::createTBAANode(StringRef Name, MDNode *Parent,
184                                   bool isConstant) {
185   if (isConstant) {
186     Constant *Flags = ConstantInt::get(Type::getInt64Ty(Context), 1);
187     return MDNode::get(Context,
188                        {createString(Name), Parent, createConstant(Flags)});
189   }
190   return MDNode::get(Context, {createString(Name), Parent});
191 }
192 
193 MDNode *MDBuilder::createAliasScopeDomain(StringRef Name) {
194   return MDNode::get(Context, createString(Name));
195 }
196 
197 MDNode *MDBuilder::createAliasScope(StringRef Name, MDNode *Domain) {
198   return MDNode::get(Context, {createString(Name), Domain});
199 }
200 
201 /// Return metadata for a tbaa.struct node with the given
202 /// struct field descriptions.
203 MDNode *MDBuilder::createTBAAStructNode(ArrayRef<TBAAStructField> Fields) {
204   SmallVector<Metadata *, 4> Vals(Fields.size() * 3);
205   Type *Int64 = Type::getInt64Ty(Context);
206   for (unsigned i = 0, e = Fields.size(); i != e; ++i) {
207     Vals[i * 3 + 0] = createConstant(ConstantInt::get(Int64, Fields[i].Offset));
208     Vals[i * 3 + 1] = createConstant(ConstantInt::get(Int64, Fields[i].Size));
209     Vals[i * 3 + 2] = Fields[i].Type;
210   }
211   return MDNode::get(Context, Vals);
212 }
213 
214 /// Return metadata for a TBAA struct node in the type DAG
215 /// with the given name, a list of pairs (offset, field type in the type DAG).
216 MDNode *MDBuilder::createTBAAStructTypeNode(
217     StringRef Name, ArrayRef<std::pair<MDNode *, uint64_t>> Fields) {
218   SmallVector<Metadata *, 4> Ops(Fields.size() * 2 + 1);
219   Type *Int64 = Type::getInt64Ty(Context);
220   Ops[0] = createString(Name);
221   for (unsigned i = 0, e = Fields.size(); i != e; ++i) {
222     Ops[i * 2 + 1] = Fields[i].first;
223     Ops[i * 2 + 2] = createConstant(ConstantInt::get(Int64, Fields[i].second));
224   }
225   return MDNode::get(Context, Ops);
226 }
227 
228 /// Return metadata for a TBAA scalar type node with the
229 /// given name, an offset and a parent in the TBAA type DAG.
230 MDNode *MDBuilder::createTBAAScalarTypeNode(StringRef Name, MDNode *Parent,
231                                             uint64_t Offset) {
232   ConstantInt *Off = ConstantInt::get(Type::getInt64Ty(Context), Offset);
233   return MDNode::get(Context,
234                      {createString(Name), Parent, createConstant(Off)});
235 }
236 
237 /// Return metadata for a TBAA tag node with the given
238 /// base type, access type and offset relative to the base type.
239 MDNode *MDBuilder::createTBAAStructTagNode(MDNode *BaseType, MDNode *AccessType,
240                                            uint64_t Offset, bool IsConstant) {
241   IntegerType *Int64 = Type::getInt64Ty(Context);
242   ConstantInt *Off = ConstantInt::get(Int64, Offset);
243   if (IsConstant) {
244     return MDNode::get(Context, {BaseType, AccessType, createConstant(Off),
245                                  createConstant(ConstantInt::get(Int64, 1))});
246   }
247   return MDNode::get(Context, {BaseType, AccessType, createConstant(Off)});
248 }
249 
250 MDNode *MDBuilder::createTBAATypeNode(MDNode *Parent, uint64_t Size,
251                                       Metadata *Id,
252                                       ArrayRef<TBAAStructField> Fields) {
253   SmallVector<Metadata *, 4> Ops(3 + Fields.size() * 3);
254   Type *Int64 = Type::getInt64Ty(Context);
255   Ops[0] = Parent;
256   Ops[1] = createConstant(ConstantInt::get(Int64, Size));
257   Ops[2] = Id;
258   for (unsigned I = 0, E = Fields.size(); I != E; ++I) {
259     Ops[I * 3 + 3] = Fields[I].Type;
260     Ops[I * 3 + 4] = createConstant(ConstantInt::get(Int64, Fields[I].Offset));
261     Ops[I * 3 + 5] = createConstant(ConstantInt::get(Int64, Fields[I].Size));
262   }
263   return MDNode::get(Context, Ops);
264 }
265 
266 MDNode *MDBuilder::createTBAAAccessTag(MDNode *BaseType, MDNode *AccessType,
267                                        uint64_t Offset, uint64_t Size,
268                                        bool IsImmutable) {
269   IntegerType *Int64 = Type::getInt64Ty(Context);
270   auto *OffsetNode = createConstant(ConstantInt::get(Int64, Offset));
271   auto *SizeNode = createConstant(ConstantInt::get(Int64, Size));
272   if (IsImmutable) {
273     auto *ImmutabilityFlagNode = createConstant(ConstantInt::get(Int64, 1));
274     return MDNode::get(Context, {BaseType, AccessType, OffsetNode, SizeNode,
275                                  ImmutabilityFlagNode});
276   }
277   return MDNode::get(Context, {BaseType, AccessType, OffsetNode, SizeNode});
278 }
279 
280 MDNode *MDBuilder::createMutableTBAAAccessTag(MDNode *Tag) {
281   MDNode *BaseType = cast<MDNode>(Tag->getOperand(0));
282   MDNode *AccessType = cast<MDNode>(Tag->getOperand(1));
283   Metadata *OffsetNode = Tag->getOperand(2);
284   uint64_t Offset = mdconst::extract<ConstantInt>(OffsetNode)->getZExtValue();
285 
286   bool NewFormat = isa<MDNode>(AccessType->getOperand(0));
287 
288   // See if the tag is already mutable.
289   unsigned ImmutabilityFlagOp = NewFormat ? 4 : 3;
290   if (Tag->getNumOperands() <= ImmutabilityFlagOp)
291     return Tag;
292 
293   // If Tag is already mutable then return it.
294   Metadata *ImmutabilityFlagNode = Tag->getOperand(ImmutabilityFlagOp);
295   if (!mdconst::extract<ConstantInt>(ImmutabilityFlagNode)->getValue())
296     return Tag;
297 
298   // Otherwise, create another node.
299   if (!NewFormat)
300     return createTBAAStructTagNode(BaseType, AccessType, Offset);
301 
302   Metadata *SizeNode = Tag->getOperand(3);
303   uint64_t Size = mdconst::extract<ConstantInt>(SizeNode)->getZExtValue();
304   return createTBAAAccessTag(BaseType, AccessType, Offset, Size);
305 }
306 
307 MDNode *MDBuilder::createIrrLoopHeaderWeight(uint64_t Weight) {
308   Metadata *Vals[] = {
309     createString("loop_header_weight"),
310     createConstant(ConstantInt::get(Type::getInt64Ty(Context), Weight)),
311   };
312   return MDNode::get(Context, Vals);
313 }
314