Resolve {GlobalValue,GloalIndirectSymol}::getBaseObject confusion

While both GlobalAlias and GlobalIFunc are GlobalIndirectSymbol, their
`getIndirectSymbol()` usage is quite different (GlobalIFunc's resolver
is an entity different from GlobalIFunc itself).

As discussed on https://lists.llvm.org/pipermail/llvm-dev/2020-September/144904.html
("[IR] Modelling of GlobalIFunc"), the name `getBaseObject` is confusing when
used with GlobalIFunc.

To resolve the confusion:

* Move GloalIndirectSymol::getBaseObject to GlobalAlias:: (GlobalIFunc should use `getResolver` instead)
* Change GlobalValue::getBaseObject not to inspect GlobalIFunc. Note: the function has 7 references.
* Add GlobalIFunc::getResolverFunction to peel off potential ConstantExpr indirection
  (`strlen` in `test/LTO/Resolution/X86/ifunc.ll`)

Note: GlobalIFunc::getResolver (like GlobalAlias::getAliasee which does not peel
off ConstantExpr indirection) is kept to be used by ValueEnumerator.

Reviewed By: ibookstein

Differential Revision: https://reviews.llvm.org/D109792

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Object/ModuleSymbolTable.cpp b/llvm/lib/Object/ModuleSymbolTable.cpp
index 9a79de7..5ae81c9 100644
--- a/llvm/lib/Object/ModuleSymbolTable.cpp
+++ b/llvm/lib/Object/ModuleSymbolTable.cpp
@@ -204,7 +204,7 @@ uint32_t ModuleSymbolTable::getSymbolFlags(Symbol S) const {
     if (GVar->isConstant())
       Res |= BasicSymbolRef::SF_Const;
   }
-  if (dyn_cast_or_null<Function>(GV->getBaseObject()))
+  if (isa_and_nonnull<Function>(GV->getBaseObject()) || isa<GlobalIFunc>(GV))
     Res |= BasicSymbolRef::SF_Executable;
   if (isa<GlobalAlias>(GV))
     Res |= BasicSymbolRef::SF_Indirect;