1 //===---- MemCpyOptimizer.h - memcpy optimization ---------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This pass performs various transformations related to eliminating memcpy
11 // calls, or transforming sets of stores into memset's.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_TRANSFORMS_SCALAR_MEMCPYOPTIMIZER_H
16 #define LLVM_TRANSFORMS_SCALAR_MEMCPYOPTIMIZER_H
17 
18 #include "llvm/ADT/STLExtras.h"
19 #include "llvm/Analysis/AliasAnalysis.h"
20 #include "llvm/Analysis/AssumptionCache.h"
21 #include "llvm/Analysis/GlobalsModRef.h"
22 #include "llvm/Analysis/MemoryDependenceAnalysis.h"
23 #include "llvm/Analysis/TargetLibraryInfo.h"
24 #include "llvm/IR/Dominators.h"
25 #include "llvm/IR/Function.h"
26 #include "llvm/IR/Instructions.h"
27 #include "llvm/IR/IntrinsicInst.h"
28 #include "llvm/IR/PassManager.h"
29 
30 namespace llvm {
31 
32 class MemCpyOptPass : public PassInfoMixin<MemCpyOptPass> {
33   MemoryDependenceResults *MD = nullptr;
34   TargetLibraryInfo *TLI = nullptr;
35   std::function<AliasAnalysis &()> LookupAliasAnalysis;
36   std::function<AssumptionCache &()> LookupAssumptionCache;
37   std::function<DominatorTree &()> LookupDomTree;
38 
39 public:
MemCpyOptPass()40   MemCpyOptPass() {}
41   PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
42   // Glue for the old PM.
43   bool runImpl(Function &F, MemoryDependenceResults *MD_,
44                TargetLibraryInfo *TLI_,
45                std::function<AliasAnalysis &()> LookupAliasAnalysis_,
46                std::function<AssumptionCache &()> LookupAssumptionCache_,
47                std::function<DominatorTree &()> LookupDomTree_);
48 
49 private:
50   // Helper functions
51   bool processStore(StoreInst *SI, BasicBlock::iterator &BBI);
52   bool processMemSet(MemSetInst *SI, BasicBlock::iterator &BBI);
53   bool processMemCpy(MemCpyInst *M);
54   bool processMemMove(MemMoveInst *M);
55   bool performCallSlotOptzn(Instruction *cpy, Value *cpyDst, Value *cpySrc,
56                             uint64_t cpyLen, unsigned cpyAlign, CallInst *C);
57   bool processMemCpyMemCpyDependence(MemCpyInst *M, MemCpyInst *MDep);
58   bool processMemSetMemCpyDependence(MemCpyInst *M, MemSetInst *MDep);
59   bool performMemCpyToMemSetOptzn(MemCpyInst *M, MemSetInst *MDep);
60   bool processByValArgument(CallSite CS, unsigned ArgNo);
61   Instruction *tryMergingIntoMemset(Instruction *I, Value *StartPtr,
62                                     Value *ByteVal);
63 
64   bool iterateOnFunction(Function &F);
65 };
66 }
67 
68 #endif // LLVM_TRANSFORMS_SCALAR_MEMCPYOPTIMIZER_H
69