Add support for handling ifuncs to GlobalValue::getBaseObject

Summary:
All GlobalIndirectSymbol types (not just GlobalAlias) should return
their base object.

Without this patch LTO would warn "Unable to determine comdat of
alias!" for an ifunc.

Reviewers: pcc

Subscribers: mehdi_amini, inglorion, llvm-commits

Differential Revision: https://reviews.llvm.org/D33202

llvm-svn: 303096

llvm/lib/IR/Globals.cpp

@@ -255,7 +255,7 @@ bool GlobalValue::canIncreaseAlignment() const {
 const GlobalObject *GlobalValue::getBaseObject() const {
   if (auto *GO = dyn_cast<GlobalObject>(this))
     return GO;
-  if (auto *GA = dyn_cast<GlobalAlias>(this))
+  if (auto *GA = dyn_cast<GlobalIndirectSymbol>(this))
     return GA->getBaseObject();
   return nullptr;
 }

llvm/test/LTO/Resolution/X86/ifunc.ll

@@ -0,0 +1,15 @@
+; RUN: opt -module-summary -o %t.bc %s
+; RUN: llvm-lto2 run %t.bc -r %t.bc,foo,pl -o %t2
+; RUN: llvm-nm %t2.0 | FileCheck %s
+; CHECK: T foo
+; CHECK: t foo_ifunc
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@foo = ifunc i32 (i32), i64 ()* @foo_ifunc
+
+define internal i64 @foo_ifunc() {
+entry:
+  ret i64 0
+}

llvm/test/Object/X86/nm-ir.ll

@@ -12,7 +12,7 @@
 ; CHECK-NEXT: C g3
 ; CHECK-NOT: g4
 ; CHECK-NEXT: T global_asm_sym
-; CHECK-NEXT: D ifunc_f1
+; CHECK-NEXT: T ifunc_f1
 ; CHECK-NEXT: t local_asm_sym
 ; CHECK-NEXT: U undef_asm_sy