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/Triple.h"
11 #include "llvm/ExecutionEngine/Orc/CloneSubModule.h"
12 #include "llvm/ExecutionEngine/Orc/IndirectionUtils.h"
13 #include "llvm/IR/CallSite.h"
14 #include "llvm/IR/IRBuilder.h"
15 #include <set>
16 
17 namespace llvm {
18 namespace orc {
19 
20 GlobalVariable* createImplPointer(Function &F, const Twine &Name,
21                                   Constant *Initializer) {
22   assert(F.getParent() && "Function isn't in a module.");
23   if (!Initializer)
24     Initializer = Constant::getNullValue(F.getType());
25   Module &M = *F.getParent();
26   return new GlobalVariable(M, F.getType(), false, GlobalValue::ExternalLinkage,
27                             Initializer, Name, nullptr,
28                             GlobalValue::NotThreadLocal, 0, true);
29 }
30 
31 void makeStub(Function &F, GlobalVariable &ImplPointer) {
32   assert(F.isDeclaration() && "Can't turn a definition into a stub.");
33   assert(F.getParent() && "Function isn't in a module.");
34   Module &M = *F.getParent();
35   BasicBlock *EntryBlock = BasicBlock::Create(M.getContext(), "entry", &F);
36   IRBuilder<> Builder(EntryBlock);
37   LoadInst *ImplAddr = Builder.CreateLoad(&ImplPointer);
38   std::vector<Value*> CallArgs;
39   for (auto &A : F.args())
40     CallArgs.push_back(&A);
41   CallInst *Call = Builder.CreateCall(ImplAddr, CallArgs);
42   Call->setTailCall();
43   Builder.CreateRet(Call);
44 }
45 
46 void partition(Module &M, const ModulePartitionMap &PMap) {
47 
48   for (auto &KVPair : PMap) {
49 
50     auto ExtractGlobalVars =
51       [&](GlobalVariable &New, const GlobalVariable &Orig,
52           ValueToValueMapTy &VMap) {
53         if (KVPair.second.count(&Orig)) {
54           copyGVInitializer(New, Orig, VMap);
55         }
56         if (New.getLinkage() == GlobalValue::PrivateLinkage) {
57           New.setLinkage(GlobalValue::ExternalLinkage);
58           New.setVisibility(GlobalValue::HiddenVisibility);
59         }
60       };
61 
62     auto ExtractFunctions =
63       [&](Function &New, const Function &Orig, ValueToValueMapTy &VMap) {
64         if (KVPair.second.count(&Orig))
65           copyFunctionBody(New, Orig, VMap);
66         if (New.getLinkage() == GlobalValue::InternalLinkage) {
67           New.setLinkage(GlobalValue::ExternalLinkage);
68           New.setVisibility(GlobalValue::HiddenVisibility);
69         }
70       };
71 
72     CloneSubModule(*KVPair.first, M, ExtractGlobalVars, ExtractFunctions,
73                    false);
74   }
75 }
76 
77 FullyPartitionedModule fullyPartition(Module &M) {
78   FullyPartitionedModule MP;
79 
80   ModulePartitionMap PMap;
81 
82   for (auto &F : M) {
83 
84     if (F.isDeclaration())
85       continue;
86 
87     std::string NewModuleName = (M.getName() + "." + F.getName()).str();
88     MP.Functions.push_back(
89       llvm::make_unique<Module>(NewModuleName, M.getContext()));
90     MP.Functions.back()->setDataLayout(M.getDataLayout());
91     PMap[MP.Functions.back().get()].insert(&F);
92   }
93 
94   MP.GlobalVars =
95     llvm::make_unique<Module>((M.getName() + ".globals_and_stubs").str(),
96                               M.getContext());
97   MP.GlobalVars->setDataLayout(M.getDataLayout());
98 
99   MP.Commons =
100     llvm::make_unique<Module>((M.getName() + ".commons").str(), M.getContext());
101   MP.Commons->setDataLayout(M.getDataLayout());
102 
103   // Make sure there's at least an empty set for the stubs map or we'll fail
104   // to clone anything for it (including the decls).
105   PMap[MP.GlobalVars.get()] = ModulePartitionMap::mapped_type();
106   for (auto &GV : M.globals())
107     if (GV.getLinkage() == GlobalValue::CommonLinkage)
108       PMap[MP.Commons.get()].insert(&GV);
109     else
110       PMap[MP.GlobalVars.get()].insert(&GV);
111 
112   partition(M, PMap);
113 
114   return MP;
115 }
116 
117 } // End namespace orc.
118 } // End namespace llvm.
119