1 //===-- CGBuilder.h - Choose IRBuilder implementation  ----------*- C++ -*-===//
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 #ifndef LLVM_CLANG_LIB_CODEGEN_CGBUILDER_H
10 #define LLVM_CLANG_LIB_CODEGEN_CGBUILDER_H
11 
12 #include "llvm/IR/DataLayout.h"
13 #include "llvm/IR/IRBuilder.h"
14 #include "Address.h"
15 #include "CodeGenTypeCache.h"
16 
17 namespace clang {
18 namespace CodeGen {
19 
20 class CodeGenFunction;
21 
22 /// This is an IRBuilder insertion helper that forwards to
23 /// CodeGenFunction::InsertHelper, which adds necessary metadata to
24 /// instructions.
25 class CGBuilderInserter final : public llvm::IRBuilderDefaultInserter {
26 public:
27   CGBuilderInserter() = default;
28   explicit CGBuilderInserter(CodeGenFunction *CGF) : CGF(CGF) {}
29 
30   /// This forwards to CodeGenFunction::InsertHelper.
31   void InsertHelper(llvm::Instruction *I, const llvm::Twine &Name,
32                     llvm::BasicBlock *BB,
33                     llvm::BasicBlock::iterator InsertPt) const override;
34 private:
35   CodeGenFunction *CGF = nullptr;
36 };
37 
38 typedef CGBuilderInserter CGBuilderInserterTy;
39 
40 typedef llvm::IRBuilder<llvm::ConstantFolder, CGBuilderInserterTy>
41     CGBuilderBaseTy;
42 
43 class CGBuilderTy : public CGBuilderBaseTy {
44   /// Storing a reference to the type cache here makes it a lot easier
45   /// to build natural-feeling, target-specific IR.
46   const CodeGenTypeCache &TypeCache;
47 public:
48   CGBuilderTy(const CodeGenTypeCache &TypeCache, llvm::LLVMContext &C)
49     : CGBuilderBaseTy(C), TypeCache(TypeCache) {}
50   CGBuilderTy(const CodeGenTypeCache &TypeCache,
51               llvm::LLVMContext &C, const llvm::ConstantFolder &F,
52               const CGBuilderInserterTy &Inserter)
53     : CGBuilderBaseTy(C, F, Inserter), TypeCache(TypeCache) {}
54   CGBuilderTy(const CodeGenTypeCache &TypeCache, llvm::Instruction *I)
55     : CGBuilderBaseTy(I), TypeCache(TypeCache) {}
56   CGBuilderTy(const CodeGenTypeCache &TypeCache, llvm::BasicBlock *BB)
57     : CGBuilderBaseTy(BB), TypeCache(TypeCache) {}
58 
59   llvm::ConstantInt *getSize(CharUnits N) {
60     return llvm::ConstantInt::get(TypeCache.SizeTy, N.getQuantity());
61   }
62   llvm::ConstantInt *getSize(uint64_t N) {
63     return llvm::ConstantInt::get(TypeCache.SizeTy, N);
64   }
65 
66   // Note that we intentionally hide the CreateLoad APIs that don't
67   // take an alignment.
68   llvm::LoadInst *CreateLoad(Address Addr, const llvm::Twine &Name = "") {
69     return CreateAlignedLoad(Addr.getPointer(),
70                              Addr.getAlignment().getAsAlign(), Name);
71   }
72   llvm::LoadInst *CreateLoad(Address Addr, const char *Name) {
73     // This overload is required to prevent string literals from
74     // ending up in the IsVolatile overload.
75     return CreateAlignedLoad(Addr.getPointer(),
76                              Addr.getAlignment().getAsAlign(), Name);
77   }
78   llvm::LoadInst *CreateLoad(Address Addr, bool IsVolatile,
79                              const llvm::Twine &Name = "") {
80     return CreateAlignedLoad(
81         Addr.getPointer(), Addr.getAlignment().getAsAlign(), IsVolatile, Name);
82   }
83 
84   using CGBuilderBaseTy::CreateAlignedLoad;
85   llvm::LoadInst *CreateAlignedLoad(llvm::Value *Addr, CharUnits Align,
86                                     const llvm::Twine &Name = "") {
87     return CreateAlignedLoad(Addr, Align.getAsAlign(), Name);
88   }
89   llvm::LoadInst *CreateAlignedLoad(llvm::Value *Addr, CharUnits Align,
90                                     const char *Name) {
91     return CreateAlignedLoad(Addr, Align.getAsAlign(), Name);
92   }
93   llvm::LoadInst *CreateAlignedLoad(llvm::Type *Ty, llvm::Value *Addr,
94                                     CharUnits Align,
95                                     const llvm::Twine &Name = "") {
96     assert(Addr->getType()->getPointerElementType() == Ty);
97     return CreateAlignedLoad(Addr, Align.getAsAlign(), Name);
98   }
99 
100   // Note that we intentionally hide the CreateStore APIs that don't
101   // take an alignment.
102   llvm::StoreInst *CreateStore(llvm::Value *Val, Address Addr,
103                                bool IsVolatile = false) {
104     return CreateAlignedStore(Val, Addr.getPointer(),
105                               Addr.getAlignment().getAsAlign(), IsVolatile);
106   }
107 
108   using CGBuilderBaseTy::CreateAlignedStore;
109   llvm::StoreInst *CreateAlignedStore(llvm::Value *Val, llvm::Value *Addr,
110                                       CharUnits Align, bool IsVolatile = false) {
111     return CreateAlignedStore(Val, Addr, Align.getAsAlign(), IsVolatile);
112   }
113 
114   // FIXME: these "default-aligned" APIs should be removed,
115   // but I don't feel like fixing all the builtin code right now.
116   llvm::StoreInst *CreateDefaultAlignedStore(llvm::Value *Val,
117                                              llvm::Value *Addr,
118                                              bool IsVolatile = false) {
119     return CGBuilderBaseTy::CreateStore(Val, Addr, IsVolatile);
120   }
121 
122   /// Emit a load from an i1 flag variable.
123   llvm::LoadInst *CreateFlagLoad(llvm::Value *Addr,
124                                  const llvm::Twine &Name = "") {
125     assert(Addr->getType()->getPointerElementType() == getInt1Ty());
126     return CreateAlignedLoad(getInt1Ty(), Addr, CharUnits::One(), Name);
127   }
128 
129   /// Emit a store to an i1 flag variable.
130   llvm::StoreInst *CreateFlagStore(bool Value, llvm::Value *Addr) {
131     assert(Addr->getType()->getPointerElementType() == getInt1Ty());
132     return CreateAlignedStore(getInt1(Value), Addr, CharUnits::One());
133   }
134 
135   using CGBuilderBaseTy::CreateBitCast;
136   Address CreateBitCast(Address Addr, llvm::Type *Ty,
137                         const llvm::Twine &Name = "") {
138     return Address(CreateBitCast(Addr.getPointer(), Ty, Name),
139                    Addr.getAlignment());
140   }
141 
142   using CGBuilderBaseTy::CreateAddrSpaceCast;
143   Address CreateAddrSpaceCast(Address Addr, llvm::Type *Ty,
144                               const llvm::Twine &Name = "") {
145     return Address(CreateAddrSpaceCast(Addr.getPointer(), Ty, Name),
146                    Addr.getAlignment());
147   }
148 
149   /// Cast the element type of the given address to a different type,
150   /// preserving information like the alignment and address space.
151   Address CreateElementBitCast(Address Addr, llvm::Type *Ty,
152                                const llvm::Twine &Name = "") {
153     auto PtrTy = Ty->getPointerTo(Addr.getAddressSpace());
154     return CreateBitCast(Addr, PtrTy, Name);
155   }
156 
157   using CGBuilderBaseTy::CreatePointerBitCastOrAddrSpaceCast;
158   Address CreatePointerBitCastOrAddrSpaceCast(Address Addr, llvm::Type *Ty,
159                                               const llvm::Twine &Name = "") {
160     llvm::Value *Ptr =
161       CreatePointerBitCastOrAddrSpaceCast(Addr.getPointer(), Ty, Name);
162     return Address(Ptr, Addr.getAlignment());
163   }
164 
165   /// Given
166   ///   %addr = {T1, T2...}* ...
167   /// produce
168   ///   %name = getelementptr inbounds %addr, i32 0, i32 index
169   ///
170   /// This API assumes that drilling into a struct like this is always an
171   /// inbounds operation.
172   using CGBuilderBaseTy::CreateStructGEP;
173   Address CreateStructGEP(Address Addr, unsigned Index,
174                           const llvm::Twine &Name = "") {
175     llvm::StructType *ElTy = cast<llvm::StructType>(Addr.getElementType());
176     const llvm::DataLayout &DL = BB->getParent()->getParent()->getDataLayout();
177     const llvm::StructLayout *Layout = DL.getStructLayout(ElTy);
178     auto Offset = CharUnits::fromQuantity(Layout->getElementOffset(Index));
179 
180     return Address(CreateStructGEP(Addr.getElementType(),
181                                    Addr.getPointer(), Index, Name),
182                    Addr.getAlignment().alignmentAtOffset(Offset));
183   }
184 
185   /// Given
186   ///   %addr = [n x T]* ...
187   /// produce
188   ///   %name = getelementptr inbounds %addr, i64 0, i64 index
189   /// where i64 is actually the target word size.
190   ///
191   /// This API assumes that drilling into an array like this is always
192   /// an inbounds operation.
193   Address CreateConstArrayGEP(Address Addr, uint64_t Index,
194                               const llvm::Twine &Name = "") {
195     llvm::ArrayType *ElTy = cast<llvm::ArrayType>(Addr.getElementType());
196     const llvm::DataLayout &DL = BB->getParent()->getParent()->getDataLayout();
197     CharUnits EltSize =
198         CharUnits::fromQuantity(DL.getTypeAllocSize(ElTy->getElementType()));
199 
200     return Address(
201         CreateInBoundsGEP(Addr.getPointer(),
202                           {getSize(CharUnits::Zero()), getSize(Index)}, Name),
203         Addr.getAlignment().alignmentAtOffset(Index * EltSize));
204   }
205 
206   /// Given
207   ///   %addr = T* ...
208   /// produce
209   ///   %name = getelementptr inbounds %addr, i64 index
210   /// where i64 is actually the target word size.
211   Address CreateConstInBoundsGEP(Address Addr, uint64_t Index,
212                                  const llvm::Twine &Name = "") {
213     llvm::Type *ElTy = Addr.getElementType();
214     const llvm::DataLayout &DL = BB->getParent()->getParent()->getDataLayout();
215     CharUnits EltSize = CharUnits::fromQuantity(DL.getTypeAllocSize(ElTy));
216 
217     return Address(CreateInBoundsGEP(Addr.getElementType(), Addr.getPointer(),
218                                      getSize(Index), Name),
219                    Addr.getAlignment().alignmentAtOffset(Index * EltSize));
220   }
221 
222   /// Given
223   ///   %addr = T* ...
224   /// produce
225   ///   %name = getelementptr inbounds %addr, i64 index
226   /// where i64 is actually the target word size.
227   Address CreateConstGEP(Address Addr, uint64_t Index,
228                          const llvm::Twine &Name = "") {
229     const llvm::DataLayout &DL = BB->getParent()->getParent()->getDataLayout();
230     CharUnits EltSize =
231         CharUnits::fromQuantity(DL.getTypeAllocSize(Addr.getElementType()));
232 
233     return Address(CreateGEP(Addr.getElementType(), Addr.getPointer(),
234                              getSize(Index), Name),
235                    Addr.getAlignment().alignmentAtOffset(Index * EltSize));
236   }
237 
238   /// Given a pointer to i8, adjust it by a given constant offset.
239   Address CreateConstInBoundsByteGEP(Address Addr, CharUnits Offset,
240                                      const llvm::Twine &Name = "") {
241     assert(Addr.getElementType() == TypeCache.Int8Ty);
242     return Address(CreateInBoundsGEP(Addr.getPointer(), getSize(Offset), Name),
243                    Addr.getAlignment().alignmentAtOffset(Offset));
244   }
245   Address CreateConstByteGEP(Address Addr, CharUnits Offset,
246                              const llvm::Twine &Name = "") {
247     assert(Addr.getElementType() == TypeCache.Int8Ty);
248     return Address(CreateGEP(Addr.getPointer(), getSize(Offset), Name),
249                    Addr.getAlignment().alignmentAtOffset(Offset));
250   }
251 
252   using CGBuilderBaseTy::CreateConstInBoundsGEP2_32;
253   Address CreateConstInBoundsGEP2_32(Address Addr, unsigned Idx0, unsigned Idx1,
254                                      const llvm::Twine &Name = "") {
255     const llvm::DataLayout &DL = BB->getParent()->getParent()->getDataLayout();
256 
257     auto *GEP = cast<llvm::GetElementPtrInst>(CreateConstInBoundsGEP2_32(
258         Addr.getElementType(), Addr.getPointer(), Idx0, Idx1, Name));
259     llvm::APInt Offset(
260         DL.getIndexSizeInBits(Addr.getType()->getPointerAddressSpace()), 0,
261         /*isSigned=*/true);
262     if (!GEP->accumulateConstantOffset(DL, Offset))
263       llvm_unreachable("offset of GEP with constants is always computable");
264     return Address(GEP, Addr.getAlignment().alignmentAtOffset(
265                             CharUnits::fromQuantity(Offset.getSExtValue())));
266   }
267 
268   using CGBuilderBaseTy::CreateMemCpy;
269   llvm::CallInst *CreateMemCpy(Address Dest, Address Src, llvm::Value *Size,
270                                bool IsVolatile = false) {
271     return CreateMemCpy(Dest.getPointer(), Dest.getAlignment().getAsAlign(),
272                         Src.getPointer(), Src.getAlignment().getAsAlign(), Size,
273                         IsVolatile);
274   }
275   llvm::CallInst *CreateMemCpy(Address Dest, Address Src, uint64_t Size,
276                                bool IsVolatile = false) {
277     return CreateMemCpy(Dest.getPointer(), Dest.getAlignment().getAsAlign(),
278                         Src.getPointer(), Src.getAlignment().getAsAlign(), Size,
279                         IsVolatile);
280   }
281 
282   using CGBuilderBaseTy::CreateMemCpyInline;
283   llvm::CallInst *CreateMemCpyInline(Address Dest, Address Src, uint64_t Size) {
284     return CreateMemCpyInline(
285         Dest.getPointer(), Dest.getAlignment().getAsAlign(), Src.getPointer(),
286         Src.getAlignment().getAsAlign(), getInt64(Size));
287   }
288 
289   using CGBuilderBaseTy::CreateMemMove;
290   llvm::CallInst *CreateMemMove(Address Dest, Address Src, llvm::Value *Size,
291                                 bool IsVolatile = false) {
292     return CreateMemMove(Dest.getPointer(), Dest.getAlignment().getAsAlign(),
293                          Src.getPointer(), Src.getAlignment().getAsAlign(),
294                          Size, IsVolatile);
295   }
296 
297   using CGBuilderBaseTy::CreateMemSet;
298   llvm::CallInst *CreateMemSet(Address Dest, llvm::Value *Value,
299                                llvm::Value *Size, bool IsVolatile = false) {
300     return CreateMemSet(Dest.getPointer(), Value, Size,
301                         Dest.getAlignment().getAsAlign(), IsVolatile);
302   }
303 
304   using CGBuilderBaseTy::CreatePreserveStructAccessIndex;
305   Address CreatePreserveStructAccessIndex(Address Addr,
306                                           unsigned Index,
307                                           unsigned FieldIndex,
308                                           llvm::MDNode *DbgInfo) {
309     llvm::StructType *ElTy = cast<llvm::StructType>(Addr.getElementType());
310     const llvm::DataLayout &DL = BB->getParent()->getParent()->getDataLayout();
311     const llvm::StructLayout *Layout = DL.getStructLayout(ElTy);
312     auto Offset = CharUnits::fromQuantity(Layout->getElementOffset(Index));
313 
314     return Address(CreatePreserveStructAccessIndex(ElTy, Addr.getPointer(),
315                                                    Index, FieldIndex, DbgInfo),
316                    Addr.getAlignment().alignmentAtOffset(Offset));
317   }
318 };
319 
320 }  // end namespace CodeGen
321 }  // end namespace clang
322 
323 #endif
324