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 
18 namespace llvm {
19 namespace orc {
20 
21 GlobalVariable* createImplPointer(Function &F, const Twine &Name,
22                                   Constant *Initializer) {
23   assert(F.getParent() && "Function isn't in a module.");
24   if (!Initializer)
25     Initializer = Constant::getNullValue(F.getType());
26   Module &M = *F.getParent();
27   return new GlobalVariable(M, F.getType(), false, GlobalValue::ExternalLinkage,
28                             Initializer, Name, nullptr,
29                             GlobalValue::NotThreadLocal, 0, true);
30 }
31 
32 void makeStub(Function &F, GlobalVariable &ImplPointer) {
33   assert(F.isDeclaration() && "Can't turn a definition into a stub.");
34   assert(F.getParent() && "Function isn't in a module.");
35   Module &M = *F.getParent();
36   BasicBlock *EntryBlock = BasicBlock::Create(M.getContext(), "entry", &F);
37   IRBuilder<> Builder(EntryBlock);
38   LoadInst *ImplAddr = Builder.CreateLoad(&ImplPointer);
39   std::vector<Value*> CallArgs;
40   for (auto &A : F.args())
41     CallArgs.push_back(&A);
42   CallInst *Call = Builder.CreateCall(ImplAddr, CallArgs);
43   Call->setTailCall();
44   Builder.CreateRet(Call);
45 }
46 
47 void partition(Module &M, const ModulePartitionMap &PMap) {
48 
49   for (auto &KVPair : PMap) {
50 
51     auto ExtractGlobalVars =
52       [&](GlobalVariable &New, const GlobalVariable &Orig,
53           ValueToValueMapTy &VMap) {
54         if (KVPair.second.count(&Orig)) {
55           copyGVInitializer(New, Orig, VMap);
56         }
57         if (New.hasLocalLinkage()) {
58           New.setLinkage(GlobalValue::ExternalLinkage);
59           New.setVisibility(GlobalValue::HiddenVisibility);
60         }
61       };
62 
63     auto ExtractFunctions =
64       [&](Function &New, const Function &Orig, ValueToValueMapTy &VMap) {
65         if (KVPair.second.count(&Orig))
66           copyFunctionBody(New, Orig, VMap);
67         if (New.hasLocalLinkage()) {
68           New.setLinkage(GlobalValue::ExternalLinkage);
69           New.setVisibility(GlobalValue::HiddenVisibility);
70         }
71       };
72 
73     CloneSubModule(*KVPair.first, M, ExtractGlobalVars, ExtractFunctions,
74                    false);
75   }
76 }
77 
78 FullyPartitionedModule fullyPartition(Module &M) {
79   FullyPartitionedModule MP;
80 
81   ModulePartitionMap PMap;
82 
83   for (auto &F : M) {
84 
85     if (F.isDeclaration())
86       continue;
87 
88     std::string NewModuleName = (M.getName() + "." + F.getName()).str();
89     MP.Functions.push_back(
90       llvm::make_unique<Module>(NewModuleName, M.getContext()));
91     MP.Functions.back()->setDataLayout(M.getDataLayout());
92     PMap[MP.Functions.back().get()].insert(&F);
93   }
94 
95   MP.GlobalVars =
96     llvm::make_unique<Module>((M.getName() + ".globals_and_stubs").str(),
97                               M.getContext());
98   MP.GlobalVars->setDataLayout(M.getDataLayout());
99 
100   MP.Commons =
101     llvm::make_unique<Module>((M.getName() + ".commons").str(), M.getContext());
102   MP.Commons->setDataLayout(M.getDataLayout());
103 
104   // Make sure there's at least an empty set for the stubs map or we'll fail
105   // to clone anything for it (including the decls).
106   PMap[MP.GlobalVars.get()] = ModulePartitionMap::mapped_type();
107   for (auto &GV : M.globals())
108     if (GV.getLinkage() == GlobalValue::CommonLinkage)
109       PMap[MP.Commons.get()].insert(&GV);
110     else
111       PMap[MP.GlobalVars.get()].insert(&GV);
112 
113   partition(M, PMap);
114 
115   return MP;
116 }
117 
118 } // End namespace orc.
119 } // End namespace llvm.
120