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//===- NameAnonFunctions.cpp - ThinLTO Summary-based Function Import ------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements naming anonymous function to make sure they can be
// refered to by ThinLTO.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/SmallString.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/MD5.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"
using namespace llvm;
// Compute a "unique" hash for the module based on the name of the public
// functions.
class ModuleHasher {
Module &TheModule;
std::string TheHash;
public:
ModuleHasher(Module &M) : TheModule(M) {}
/// Return the lazily computed hash.
std::string &get() {
if (!TheHash.empty())
// Cache hit :)
return TheHash;
MD5 Hasher;
for (auto &F : TheModule) {
if (F.isDeclaration() || F.hasLocalLinkage() || !F.hasName())
continue;
auto Name = F.getName();
Hasher.update(Name);
}
for (auto &GV : TheModule.globals()) {
if (GV.isDeclaration() || GV.hasLocalLinkage() || !GV.hasName())
continue;
auto Name = GV.getName();
Hasher.update(Name);
}
// Now return the result.
MD5::MD5Result Hash;
Hasher.final(Hash);
SmallString<32> Result;
MD5::stringifyResult(Hash, Result);
TheHash = Result.str();
return TheHash;
}
};
// Rename all the anon functions in the module
bool llvm::nameUnamedFunctions(Module &M) {
bool Changed = false;
ModuleHasher ModuleHash(M);
int count = 0;
for (auto &F : M) {
if (F.hasName())
continue;
F.setName(Twine("anon.") + ModuleHash.get() + "." + Twine(count++));
Changed = true;
}
return Changed;
}
namespace {
// Simple pass that provides a name to every anon function.
class NameAnonFunction : public ModulePass {
public:
/// Pass identification, replacement for typeid
static char ID;
/// Specify pass name for debug output
const char *getPassName() const override { return "Name Anon Functions"; }
explicit NameAnonFunction() : ModulePass(ID) {}
bool runOnModule(Module &M) override { return nameUnamedFunctions(M); }
};
char NameAnonFunction::ID = 0;
} // anonymous namespace
INITIALIZE_PASS_BEGIN(NameAnonFunction, "name-anon-functions",
"Provide a name to nameless functions", false, false)
INITIALIZE_PASS_END(NameAnonFunction, "name-anon-functions",
"Provide a name to nameless functions", false, false)
namespace llvm {
ModulePass *createNameAnonFunctionPass() { return new NameAnonFunction(); }
}