From 9fe245d7e05f44d42156d3f557d257e17d3ac4f0 Mon Sep 17 00:00:00 2001
From: Will Dietz <w@wdtz.org>
Date: Thu, 20 Sep 2018 19:53:59 -0500
Subject: [PATCH] llvm7: optionally use libpfm (exegesis), default off w/darwin

---
 pkgs/development/compilers/llvm/7/llvm.nix | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/pkgs/development/compilers/llvm/7/llvm.nix b/pkgs/development/compilers/llvm/7/llvm.nix
index 4f540d23c9e..67bde813fee 100644
--- a/pkgs/development/compilers/llvm/7/llvm.nix
+++ b/pkgs/development/compilers/llvm/7/llvm.nix
@@ -4,6 +4,7 @@
 , python
 , libffi
 , libbfd
+, libpfm
 , libxml2
 , ncurses
 , version
@@ -13,6 +14,7 @@
 , enableManpages ? false
 , enableSharedLibraries ? true
 , enableWasm ? true
+, enablePFM ? !stdenv.isDarwin
 }:
 
 let
@@ -36,7 +38,8 @@ in stdenv.mkDerivation (rec {
   nativeBuildInputs = [ cmake python ]
     ++ stdenv.lib.optional enableManpages python.pkgs.sphinx;
 
-  buildInputs = [ libxml2 libffi ];
+  buildInputs = [ libxml2 libffi ]
+    ++ stdenv.lib.optional enablePFM libpfm; # exegesis
 
   propagatedBuildInputs = [ ncurses zlib ];