From: Evgeniy Stepanov <eugeni.stepanov@gmail.com>
Date: Fri, 4 Dec 2015 00:45:43 +0000 (+0000)
Subject: Emit function alias to data as a function symbol.
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=cb1cb45c602578eeb8c6894e86206bade019d044

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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254674 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 2cfea650872..b8604240b5d 100644
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/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:
diff --git a/test/CodeGen/Generic/function-alias.ll b/test/CodeGen/Generic/function-alias.ll
new file mode 100644
index 00000000000..d68d75d5578
--- /dev/null
+++ b/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