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      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/CloneSubModule.h"
     13 #include "llvm/ExecutionEngine/Orc/IndirectionUtils.h"
     14 #include "llvm/IR/CallSite.h"
     15 #include "llvm/IR/IRBuilder.h"
     16 #include <set>
     17 #include <sstream>
     18 
     19 namespace llvm {
     20 namespace orc {
     21 
     22 Constant* createIRTypedAddress(FunctionType &FT, TargetAddress Addr) {
     23   Constant *AddrIntVal =
     24     ConstantInt::get(Type::getInt64Ty(FT.getContext()), Addr);
     25   Constant *AddrPtrVal =
     26     ConstantExpr::getCast(Instruction::IntToPtr, AddrIntVal,
     27                           PointerType::get(&FT, 0));
     28   return AddrPtrVal;
     29 }
     30 
     31 GlobalVariable* createImplPointer(PointerType &PT, Module &M,
     32                                   const Twine &Name, Constant *Initializer) {
     33   if (!Initializer)
     34     Initializer = Constant::getNullValue(&PT);
     35   return new GlobalVariable(M, &PT, false, GlobalValue::ExternalLinkage,
     36                             Initializer, Name, nullptr,
     37                             GlobalValue::NotThreadLocal, 0, true);
     38 }
     39 
     40 void makeStub(Function &F, GlobalVariable &ImplPointer) {
     41   assert(F.isDeclaration() && "Can't turn a definition into a stub.");
     42   assert(F.getParent() && "Function isn't in a module.");
     43   Module &M = *F.getParent();
     44   BasicBlock *EntryBlock = BasicBlock::Create(M.getContext(), "entry", &F);
     45   IRBuilder<> Builder(EntryBlock);
     46   LoadInst *ImplAddr = Builder.CreateLoad(&ImplPointer);
     47   std::vector<Value*> CallArgs;
     48   for (auto &A : F.args())
     49     CallArgs.push_back(&A);
     50   CallInst *Call = Builder.CreateCall(ImplAddr, CallArgs);
     51   Call->setTailCall();
     52   Builder.CreateRet(Call);
     53 }
     54 
     55 // Utility class for renaming global values and functions during partitioning.
     56 class GlobalRenamer {
     57 public:
     58 
     59   static bool needsRenaming(const Value &New) {
     60     if (!New.hasName() || New.getName().startswith("\01L"))
     61       return true;
     62     return false;
     63   }
     64 
     65   const std::string& getRename(const Value &Orig) {
     66     // See if we have a name for this global.
     67     {
     68       auto I = Names.find(&Orig);
     69       if (I != Names.end())
     70         return I->second;
     71     }
     72 
     73     // Nope. Create a new one.
     74     // FIXME: Use a more robust uniquing scheme. (This may blow up if the user
     75     //        writes a "__orc_anon[[:digit:]]* method).
     76     unsigned ID = Names.size();
     77     std::ostringstream NameStream;
     78     NameStream << "__orc_anon" << ID++;
     79     auto I = Names.insert(std::make_pair(&Orig, NameStream.str()));
     80     return I.first->second;
     81   }
     82 private:
     83   DenseMap<const Value*, std::string> Names;
     84 };
     85 
     86 void partition(Module &M, const ModulePartitionMap &PMap) {
     87 
     88   GlobalRenamer Renamer;
     89 
     90   for (auto &KVPair : PMap) {
     91 
     92     auto ExtractGlobalVars =
     93       [&](GlobalVariable &New, const GlobalVariable &Orig,
     94           ValueToValueMapTy &VMap) {
     95         if (KVPair.second.count(&Orig)) {
     96           copyGVInitializer(New, Orig, VMap);
     97         }
     98         if (New.hasLocalLinkage()) {
     99           if (Renamer.needsRenaming(New))
    100             New.setName(Renamer.getRename(Orig));
    101           New.setLinkage(GlobalValue::ExternalLinkage);
    102           New.setVisibility(GlobalValue::HiddenVisibility);
    103         }
    104         assert(!Renamer.needsRenaming(New) && "Invalid global name.");
    105       };
    106 
    107     auto ExtractFunctions =
    108       [&](Function &New, const Function &Orig, ValueToValueMapTy &VMap) {
    109         if (KVPair.second.count(&Orig))
    110           copyFunctionBody(New, Orig, VMap);
    111         if (New.hasLocalLinkage()) {
    112           if (Renamer.needsRenaming(New))
    113             New.setName(Renamer.getRename(Orig));
    114           New.setLinkage(GlobalValue::ExternalLinkage);
    115           New.setVisibility(GlobalValue::HiddenVisibility);
    116         }
    117         assert(!Renamer.needsRenaming(New) && "Invalid function name.");
    118       };
    119 
    120     CloneSubModule(*KVPair.first, M, ExtractGlobalVars, ExtractFunctions,
    121                    false);
    122   }
    123 }
    124 
    125 FullyPartitionedModule fullyPartition(Module &M) {
    126   FullyPartitionedModule MP;
    127 
    128   ModulePartitionMap PMap;
    129 
    130   for (auto &F : M) {
    131 
    132     if (F.isDeclaration())
    133       continue;
    134 
    135     std::string NewModuleName = (M.getName() + "." + F.getName()).str();
    136     MP.Functions.push_back(
    137       llvm::make_unique<Module>(NewModuleName, M.getContext()));
    138     MP.Functions.back()->setDataLayout(M.getDataLayout());
    139     PMap[MP.Functions.back().get()].insert(&F);
    140   }
    141 
    142   MP.GlobalVars =
    143     llvm::make_unique<Module>((M.getName() + ".globals_and_stubs").str(),
    144                               M.getContext());
    145   MP.GlobalVars->setDataLayout(M.getDataLayout());
    146 
    147   MP.Commons =
    148     llvm::make_unique<Module>((M.getName() + ".commons").str(), M.getContext());
    149   MP.Commons->setDataLayout(M.getDataLayout());
    150 
    151   // Make sure there's at least an empty set for the stubs map or we'll fail
    152   // to clone anything for it (including the decls).
    153   PMap[MP.GlobalVars.get()] = ModulePartitionMap::mapped_type();
    154   for (auto &GV : M.globals())
    155     if (GV.getLinkage() == GlobalValue::CommonLinkage)
    156       PMap[MP.Commons.get()].insert(&GV);
    157     else
    158       PMap[MP.GlobalVars.get()].insert(&GV);
    159 
    160   partition(M, PMap);
    161 
    162   return MP;
    163 }
    164 
    165 } // End namespace orc.
    166 } // End namespace llvm.
    167