Allow alias to point to an arbitrary ConstantExpr.

This  patch changes GlobalAlias to point to an arbitrary ConstantExpr and it is
up to MC (or the system assembler) to decide if that expression is valid or not.

This reduces our ability to diagnose invalid uses and how early we can spot
them, but it also lets us do things like

@test5 = alias inttoptr(i32 sub (i32 ptrtoint (i32* @test2 to i32),
                                 i32 ptrtoint (i32* @bar to i32)) to i32*)

An important implication of this patch is that the notion of aliased global
doesn't exist any more. The alias has to encode the information needed to
access it in its metadata (linkage, visibility, type, etc).

Another consequence to notice is that getSection has to return a "const char *".
It could return a NullTerminatedStringRef if there was such a thing, but when
that was proposed the decision was to just uses "const char*" for that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210062 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 2 insertions, 6 deletions

diff --git a/tools/llvm-nm/llvm-nm.cpp b/tools/llvm-nm/llvm-nm.cpp
index d1cfefe6a3..476b49486a 100644
--- a/tools/llvm-nm/llvm-nm.cpp
+++ b/tools/llvm-nm/llvm-nm.cpp
@@ -415,15 +415,11 @@ static char getSymbolNMTypeChar(MachOObjectFile &Obj, basic_symbol_iterator I) {
 }
 
 static char getSymbolNMTypeChar(const GlobalValue &GV) {
-  if (isa<Function>(GV))
+  if (GV.getType()->getElementType()->isFunctionTy())
     return 't';
   // FIXME: should we print 'b'? At the IR level we cannot be sure if this
   // will be in bss or not, but we could approximate.
-  if (isa<GlobalVariable>(GV))
-    return 'd';
-  const GlobalAlias *GA = cast<GlobalAlias>(&GV);
-  const GlobalValue *AliasedGV = GA->getAliasee();
-  return getSymbolNMTypeChar(*AliasedGV);
+  return 'd';
 }
 
 static char getSymbolNMTypeChar(IRObjectFile &Obj, basic_symbol_iterator I) {