1 //===- GlobalsModRef.h - Simple Mod/Ref AA for Globals ----------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 /// This is the interface for a simple mod/ref and alias analysis over globals.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_ANALYSIS_GLOBALSMODREF_H
15 #define LLVM_ANALYSIS_GLOBALSMODREF_H
17 #include "llvm/Analysis/AliasAnalysis.h"
18 #include "llvm/Analysis/CallGraph.h"
19 #include "llvm/IR/Constants.h"
20 #include "llvm/IR/Function.h"
21 #include "llvm/IR/Module.h"
22 #include "llvm/IR/ValueHandle.h"
23 #include "llvm/Pass.h"
28 /// An alias analysis result set for globals.
30 /// This focuses on handling aliasing properties of globals and interprocedural
31 /// function call mod/ref information.
32 class GlobalsAAResult : public AAResultBase<GlobalsAAResult> {
33 friend AAResultBase<GlobalsAAResult>;
39 /// The globals that do not have their addresses taken.
40 SmallPtrSet<const GlobalValue *, 8> NonAddressTakenGlobals;
42 /// IndirectGlobals - The memory pointed to by this global is known to be
43 /// 'owned' by the global.
44 SmallPtrSet<const GlobalValue *, 8> IndirectGlobals;
46 /// AllocsForIndirectGlobals - If an instruction allocates memory for an
47 /// indirect global, this map indicates which one.
48 DenseMap<const Value *, const GlobalValue *> AllocsForIndirectGlobals;
50 /// For each function, keep track of what globals are modified or read.
51 DenseMap<const Function *, FunctionInfo> FunctionInfos;
53 /// A map of functions to SCC. The SCCs are described by a simple integer
54 /// ID that is only useful for comparing for equality (are two functions
55 /// in the same SCC or not?)
56 DenseMap<const Function *, unsigned> FunctionToSCCMap;
58 /// Handle to clear this analysis on deletion of values.
59 struct DeletionCallbackHandle final : CallbackVH {
61 std::list<DeletionCallbackHandle>::iterator I;
63 DeletionCallbackHandle(GlobalsAAResult &GAR, Value *V)
64 : CallbackVH(V), GAR(&GAR) {}
66 void deleted() override;
69 /// List of callbacks for globals being tracked by this analysis. Note that
70 /// these objects are quite large, but we only anticipate having one per
71 /// global tracked by this analysis. There are numerous optimizations we
72 /// could perform to the memory utilization here if this becomes a problem.
73 std::list<DeletionCallbackHandle> Handles;
75 explicit GlobalsAAResult(const DataLayout &DL, const TargetLibraryInfo &TLI);
78 GlobalsAAResult(GlobalsAAResult &&Arg);
80 static GlobalsAAResult analyzeModule(Module &M, const TargetLibraryInfo &TLI,
83 //------------------------------------------------
84 // Implement the AliasAnalysis API
86 AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB);
88 using AAResultBase::getModRefInfo;
89 ModRefInfo getModRefInfo(ImmutableCallSite CS, const MemoryLocation &Loc);
91 /// getModRefBehavior - Return the behavior of the specified function if
92 /// called from the specified call site. The call site may be null in which
93 /// case the most generic behavior of this function should be returned.
94 FunctionModRefBehavior getModRefBehavior(const Function *F);
96 /// getModRefBehavior - Return the behavior of the specified function if
97 /// called from the specified call site. The call site may be null in which
98 /// case the most generic behavior of this function should be returned.
99 FunctionModRefBehavior getModRefBehavior(ImmutableCallSite CS);
102 FunctionInfo *getFunctionInfo(const Function *F);
104 void AnalyzeGlobals(Module &M);
105 void AnalyzeCallGraph(CallGraph &CG, Module &M);
106 bool AnalyzeUsesOfPointer(Value *V,
107 SmallPtrSetImpl<Function *> *Readers = nullptr,
108 SmallPtrSetImpl<Function *> *Writers = nullptr,
109 GlobalValue *OkayStoreDest = nullptr);
110 bool AnalyzeIndirectGlobalMemory(GlobalValue *GV);
111 void CollectSCCMembership(CallGraph &CG);
113 bool isNonEscapingGlobalNoAlias(const GlobalValue *GV, const Value *V);
114 ModRefInfo getModRefInfoForArgument(ImmutableCallSite CS,
115 const GlobalValue *GV);
118 /// Analysis pass providing a never-invalidated alias analysis result.
121 typedef GlobalsAAResult Result;
123 /// \brief Opaque, unique identifier for this analysis pass.
124 static void *ID() { return (void *)&PassID; }
126 GlobalsAAResult run(Module &M, AnalysisManager<Module> *AM);
128 /// \brief Provide access to a name for this pass for debugging purposes.
129 static StringRef name() { return "GlobalsAA"; }
135 /// Legacy wrapper pass to provide the GlobalsAAResult object.
136 class GlobalsAAWrapperPass : public ModulePass {
137 std::unique_ptr<GlobalsAAResult> Result;
142 GlobalsAAWrapperPass();
144 GlobalsAAResult &getResult() { return *Result; }
145 const GlobalsAAResult &getResult() const { return *Result; }
147 bool runOnModule(Module &M) override;
148 bool doFinalization(Module &M) override;
149 void getAnalysisUsage(AnalysisUsage &AU) const override;
152 //===--------------------------------------------------------------------===//
154 // createGlobalsAAWrapperPass - This pass provides alias and mod/ref info for
155 // global values that do not have their addresses taken.
157 ModulePass *createGlobalsAAWrapperPass();