Add a pass to name anonymous/nameless function
Summary:
For correct handling of alias to nameless
function, we need to be able to refer them through a GUID in the summary.
Here we name them using a hash of the non-private global names in the module.
Reviewers: tejohnson
Subscribers: joker.eph, llvm-commits
Differential Revision: http://reviews.llvm.org/D18883
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266132
diff --git a/llvm/lib/Transforms/Utils/NameAnonFunctions.cpp b/llvm/lib/Transforms/Utils/NameAnonFunctions.cpp
new file mode 100644
index 0000000..8a2208e
--- /dev/null
+++ b/llvm/lib/Transforms/Utils/NameAnonFunctions.cpp
@@ -0,0 +1,102 @@
+//===- 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 {
+Pass *createNameAnonFunctionPass() { return new NameAnonFunction(); }
+}