Fix NameAnonFunctions pass: for ThinLTO we need to rename global variables as well

[mehdi_amini]

Summary

A follow-up patch will rename this pass and the source file accordingly,
but I figured the non-NFC change will be easier to spot in isolation.

[pcc]

Do aliases and ifuncs also need to be renamed? I know that at least unnamed aliases are legal (rL239921) but I don't know about ifuncs.

[mehdi_amini]

In D24641#544320, @pcc wrote:

Do aliases and ifuncs also need to be renamed? I know that at least unnamed aliases are legal (rL239921) but I don't know about ifuncs.

I didn't know alias could be unnamed, reminds me that I need to fix the alias representation (and forbid unnamed at the same time).

So now I need another iterator for all Module globalvalues... ;)

I feel ifunc would break ThinLTO, I don't remember seeing any test for that (I'm not sure they work on MachO either).

[mehdi_amini]

Handle unnamed aliases as well

[tejohnson]

LGTM

lib/Transforms/Utils/NameAnonFunctions.cpp

 };
 } // end anonymous namespace
 
 // 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++));
+  auto RenameIfNeed = [&] (GlobalValue &GV) {
+    if (GV.hasName())
+      return;
+    GV.setName(Twine("anon.") + ModuleHash.get() + "." + Twine(count++));
     Changed = true;
-  }
+  };
+  for (auto &GO : M.global_objects())
+    RenameIfNeed(GO);
+  for (auto &GA : M.aliases())
+    RenameIfNeed(GA);
+
   return Changed;
 }
 
 namespace {
 
 // Legacy pass that provides a name to every anon function.
 class NameAnonFunctionLegacyPass : public ModulePass {
 

test/Transforms/NameAnonFunctions/rename.ll

 ; RUN: opt -S -name-anon-functions < %s | FileCheck %s
 
 
 ; foo contribute to the unique hash for the module
 define void @foo() {
     ret void
 }
 
 ; bar is internal, and does not contribute to the unique hash for the module
 define internal void @bar() {
     ret void
 }
 
+; CHECK: @anon.acbd18db4cc2f85cedef654fccc4a4d8.3 = global i8 0
+; CHECK: @anon.acbd18db4cc2f85cedef654fccc4a4d8.4 = alias i8, i8* @anon.acbd18db4cc2f85cedef654fccc4a4d8.3
 ; CHECK: define void @anon.acbd18db4cc2f85cedef654fccc4a4d8.0()
 ; CHECK: define void @anon.acbd18db4cc2f85cedef654fccc4a4d8.1()
 ; CHECK: define void @anon.acbd18db4cc2f85cedef654fccc4a4d8.2()
 
 define void @0() {
     ret void
 }
 define void @1() {
     ret void
 }
 define void @2() {
     ret void
 }
 
+
+@3 = global i8 0
+
+@4 = alias i8, i8 *@3
 No newline at end of file