1 //===---- IndirectionUtils.cpp - Utilities for call indirection in Orc ----===//
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 #include "llvm/ADT/STLExtras.h"
11 #include "llvm/ADT/Triple.h"
12 #include "llvm/ExecutionEngine/Orc/IndirectionUtils.h"
13 #include "llvm/IR/CallSite.h"
14 #include "llvm/IR/IRBuilder.h"
15 #include "llvm/Transforms/Utils/Cloning.h"
16 #include <sstream>
17 
18 namespace llvm {
19 namespace orc {
20 
21 void JITCompileCallbackManager::anchor() {}
22 void IndirectStubsManager::anchor() {}
23 
24 Constant* createIRTypedAddress(FunctionType &FT, TargetAddress Addr) {
25   Constant *AddrIntVal =
26     ConstantInt::get(Type::getInt64Ty(FT.getContext()), Addr);
27   Constant *AddrPtrVal =
28     ConstantExpr::getCast(Instruction::IntToPtr, AddrIntVal,
29                           PointerType::get(&FT, 0));
30   return AddrPtrVal;
31 }
32 
33 GlobalVariable* createImplPointer(PointerType &PT, Module &M,
34                                   const Twine &Name, Constant *Initializer) {
35   auto IP = new GlobalVariable(M, &PT, false, GlobalValue::ExternalLinkage,
36                                Initializer, Name, nullptr,
37                                GlobalValue::NotThreadLocal, 0, true);
38   IP->setVisibility(GlobalValue::HiddenVisibility);
39   return IP;
40 }
41 
42 void makeStub(Function &F, Value &ImplPointer) {
43   assert(F.isDeclaration() && "Can't turn a definition into a stub.");
44   assert(F.getParent() && "Function isn't in a module.");
45   Module &M = *F.getParent();
46   BasicBlock *EntryBlock = BasicBlock::Create(M.getContext(), "entry", &F);
47   IRBuilder<> Builder(EntryBlock);
48   LoadInst *ImplAddr = Builder.CreateLoad(&ImplPointer);
49   std::vector<Value*> CallArgs;
50   for (auto &A : F.args())
51     CallArgs.push_back(&A);
52   CallInst *Call = Builder.CreateCall(ImplAddr, CallArgs);
53   Call->setTailCall();
54   Call->setAttributes(F.getAttributes());
55   if (F.getReturnType()->isVoidTy())
56     Builder.CreateRetVoid();
57   else
58     Builder.CreateRet(Call);
59 }
60 
61 // Utility class for renaming global values and functions during partitioning.
62 class GlobalRenamer {
63 public:
64 
65   static bool needsRenaming(const Value &New) {
66     return !New.hasName() || New.getName().startswith("\01L");
67   }
68 
69   const std::string& getRename(const Value &Orig) {
70     // See if we have a name for this global.
71     {
72       auto I = Names.find(&Orig);
73       if (I != Names.end())
74         return I->second;
75     }
76 
77     // Nope. Create a new one.
78     // FIXME: Use a more robust uniquing scheme. (This may blow up if the user
79     //        writes a "__orc_anon[[:digit:]]* method).
80     unsigned ID = Names.size();
81     std::ostringstream NameStream;
82     NameStream << "__orc_anon" << ID++;
83     auto I = Names.insert(std::make_pair(&Orig, NameStream.str()));
84     return I.first->second;
85   }
86 private:
87   DenseMap<const Value*, std::string> Names;
88 };
89 
90 static void raiseVisibilityOnValue(GlobalValue &V, GlobalRenamer &R) {
91   if (V.hasLocalLinkage()) {
92     if (R.needsRenaming(V))
93       V.setName(R.getRename(V));
94     V.setLinkage(GlobalValue::ExternalLinkage);
95     V.setVisibility(GlobalValue::HiddenVisibility);
96   }
97   V.setUnnamedAddr(false);
98   assert(!R.needsRenaming(V) && "Invalid global name.");
99 }
100 
101 void makeAllSymbolsExternallyAccessible(Module &M) {
102   GlobalRenamer Renamer;
103 
104   for (auto &F : M)
105     raiseVisibilityOnValue(F, Renamer);
106 
107   for (auto &GV : M.globals())
108     raiseVisibilityOnValue(GV, Renamer);
109 
110   for (auto &A : M.aliases())
111     raiseVisibilityOnValue(A, Renamer);
112 }
113 
114 Function* cloneFunctionDecl(Module &Dst, const Function &F,
115                             ValueToValueMapTy *VMap) {
116   assert(F.getParent() != &Dst && "Can't copy decl over existing function.");
117   Function *NewF =
118     Function::Create(cast<FunctionType>(F.getValueType()),
119                      F.getLinkage(), F.getName(), &Dst);
120   NewF->copyAttributesFrom(&F);
121 
122   if (VMap) {
123     (*VMap)[&F] = NewF;
124     auto NewArgI = NewF->arg_begin();
125     for (auto ArgI = F.arg_begin(), ArgE = F.arg_end(); ArgI != ArgE;
126          ++ArgI, ++NewArgI)
127       (*VMap)[&*ArgI] = &*NewArgI;
128   }
129 
130   return NewF;
131 }
132 
133 void moveFunctionBody(Function &OrigF, ValueToValueMapTy &VMap,
134                       ValueMaterializer *Materializer,
135                       Function *NewF) {
136   assert(!OrigF.isDeclaration() && "Nothing to move");
137   if (!NewF)
138     NewF = cast<Function>(VMap[&OrigF]);
139   else
140     assert(VMap[&OrigF] == NewF && "Incorrect function mapping in VMap.");
141   assert(NewF && "Function mapping missing from VMap.");
142   assert(NewF->getParent() != OrigF.getParent() &&
143          "moveFunctionBody should only be used to move bodies between "
144          "modules.");
145 
146   SmallVector<ReturnInst *, 8> Returns; // Ignore returns cloned.
147   CloneFunctionInto(NewF, &OrigF, VMap, /*ModuleLevelChanges=*/true, Returns,
148                     "", nullptr, nullptr, Materializer);
149   OrigF.deleteBody();
150 }
151 
152 GlobalVariable* cloneGlobalVariableDecl(Module &Dst, const GlobalVariable &GV,
153                                         ValueToValueMapTy *VMap) {
154   assert(GV.getParent() != &Dst && "Can't copy decl over existing global var.");
155   GlobalVariable *NewGV = new GlobalVariable(
156       Dst, GV.getValueType(), GV.isConstant(),
157       GV.getLinkage(), nullptr, GV.getName(), nullptr,
158       GV.getThreadLocalMode(), GV.getType()->getAddressSpace());
159   NewGV->copyAttributesFrom(&GV);
160   if (VMap)
161     (*VMap)[&GV] = NewGV;
162   return NewGV;
163 }
164 
165 void moveGlobalVariableInitializer(GlobalVariable &OrigGV,
166                                    ValueToValueMapTy &VMap,
167                                    ValueMaterializer *Materializer,
168                                    GlobalVariable *NewGV) {
169   assert(OrigGV.hasInitializer() && "Nothing to move");
170   if (!NewGV)
171     NewGV = cast<GlobalVariable>(VMap[&OrigGV]);
172   else
173     assert(VMap[&OrigGV] == NewGV &&
174            "Incorrect global variable mapping in VMap.");
175   assert(NewGV->getParent() != OrigGV.getParent() &&
176          "moveGlobalVariable should only be used to move initializers between "
177          "modules");
178 
179   NewGV->setInitializer(MapValue(OrigGV.getInitializer(), VMap, RF_None,
180                                  nullptr, Materializer));
181 }
182 
183 GlobalAlias* cloneGlobalAliasDecl(Module &Dst, const GlobalAlias &OrigA,
184                                   ValueToValueMapTy &VMap) {
185   assert(OrigA.getAliasee() && "Original alias doesn't have an aliasee?");
186   auto *NewA = GlobalAlias::create(OrigA.getValueType(),
187                                    OrigA.getType()->getPointerAddressSpace(),
188                                    OrigA.getLinkage(), OrigA.getName(), &Dst);
189   NewA->copyAttributesFrom(&OrigA);
190   VMap[&OrigA] = NewA;
191   return NewA;
192 }
193 
194 } // End namespace orc.
195 } // End namespace llvm.
196