1 //===- NameAnonFunctions.cpp - ThinLTO Summary-based Function Import ------===//
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 // This file implements naming anonymous function to make sure they can be
11 // refered to by ThinLTO.
12 //
13 //===----------------------------------------------------------------------===//
14
15 #include "llvm/ADT/SmallString.h"
16 #include "llvm/IR/Module.h"
17 #include "llvm/Support/MD5.h"
18 #include "llvm/Transforms/Utils/ModuleUtils.h"
19
20 using namespace llvm;
21
22 // Compute a "unique" hash for the module based on the name of the public
23 // functions.
24 class ModuleHasher {
25 Module &TheModule;
26 std::string TheHash;
27
28 public:
ModuleHasher(Module & M)29 ModuleHasher(Module &M) : TheModule(M) {}
30
31 /// Return the lazily computed hash.
get()32 std::string &get() {
33 if (!TheHash.empty())
34 // Cache hit :)
35 return TheHash;
36
37 MD5 Hasher;
38 for (auto &F : TheModule) {
39 if (F.isDeclaration() || F.hasLocalLinkage() || !F.hasName())
40 continue;
41 auto Name = F.getName();
42 Hasher.update(Name);
43 }
44 for (auto &GV : TheModule.globals()) {
45 if (GV.isDeclaration() || GV.hasLocalLinkage() || !GV.hasName())
46 continue;
47 auto Name = GV.getName();
48 Hasher.update(Name);
49 }
50
51 // Now return the result.
52 MD5::MD5Result Hash;
53 Hasher.final(Hash);
54 SmallString<32> Result;
55 MD5::stringifyResult(Hash, Result);
56 TheHash = Result.str();
57 return TheHash;
58 }
59 };
60
61 // Rename all the anon functions in the module
nameUnamedFunctions(Module & M)62 bool llvm::nameUnamedFunctions(Module &M) {
63 bool Changed = false;
64 ModuleHasher ModuleHash(M);
65 int count = 0;
66 for (auto &F : M) {
67 if (F.hasName())
68 continue;
69 F.setName(Twine("anon.") + ModuleHash.get() + "." + Twine(count++));
70 Changed = true;
71 }
72 return Changed;
73 }
74
75 namespace {
76
77 // Simple pass that provides a name to every anon function.
78 class NameAnonFunction : public ModulePass {
79
80 public:
81 /// Pass identification, replacement for typeid
82 static char ID;
83
84 /// Specify pass name for debug output
getPassName() const85 const char *getPassName() const override { return "Name Anon Functions"; }
86
NameAnonFunction()87 explicit NameAnonFunction() : ModulePass(ID) {}
88
runOnModule(Module & M)89 bool runOnModule(Module &M) override { return nameUnamedFunctions(M); }
90 };
91 char NameAnonFunction::ID = 0;
92
93 } // anonymous namespace
94
95 INITIALIZE_PASS_BEGIN(NameAnonFunction, "name-anon-functions",
96 "Provide a name to nameless functions", false, false)
97 INITIALIZE_PASS_END(NameAnonFunction, "name-anon-functions",
98 "Provide a name to nameless functions", false, false)
99
100 namespace llvm {
createNameAnonFunctionPass()101 ModulePass *createNameAnonFunctionPass() { return new NameAnonFunction(); }
102 }
103