Emit function alias to data as a function symbol.

CFI emits jump slots for indirect functions as a byte array
constant, and declares function-typed aliases to these constants.

This change fixes AsmPrinter to emit these aliases as function
symbols and not data symbols.

llvm-svn: 254674

llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp

@@ -1187,6 +1187,11 @@ bool AsmPrinter::doFinalization(Module &M) {
     else
       assert(Alias.hasLocalLinkage() && "Invalid alias linkage");
 
+    // Set the symbol type to function if the alias has a function type.
+    // This affects codegen when the aliasee is not a function.
+    if (Alias.getType()->getPointerElementType()->isFunctionTy())
+      OutStreamer->EmitSymbolAttribute(Name, MCSA_ELF_TypeFunction);
+
     EmitVisibility(Name, Alias.getVisibility());
 
     // Emit the directives as assignments aka .set:

llvm/test/CodeGen/Generic/function-alias.ll

@@ -0,0 +1,12 @@
+; RUN: llc < %s | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; "data" constant
+@0 = private constant <{ i8, i8 }> <{i8 15, i8 11}>, section ".text"
+
+; function-typed alias
+@ud2 = alias void (), bitcast (<{ i8, i8 }>* @0 to void ()*)
+
+; Check that "ud2" is emitted as a function symbol.
+; CHECK: .type{{.*}}ud2,@function