Add note about LLVM 8+ not being supported yet. Issue #392

README.md

@@ -2,7 +2,6 @@
 
 [![Build Status](https://travis-ci.org/nickg/nvc.svg?branch=master)](https://travis-ci.org/nickg/nvc)
 [![Windows status](https://ci.appveyor.com/api/projects/status/7eo8mjn98misbhva/branch/master?svg=true)](https://ci.appveyor.com/project/nickg72247/nvc/branch/master)
-[![Join the chat at https://gitter.im/nvc-vhdl/Lobby](https://badges.gitter.im/nvc-vhdl/Lobby.svg)](https://gitter.im/nvc-vhdl/Lobby?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 
 NVC is a GPLv3 VHDL compiler and simulator aiming for IEEE 1076-2002 compliance. See
 these [blog posts](http://www.doof.me.uk/category/vhdl/) for background
@@ -52,7 +51,8 @@ To build from a released tarball:
  sudo make install
 
 To use a specific version of LLVM add `--with-llvm=/path/to/llvm-config`
-to the configure command. LLVM 3.8 or later is required.
+to the configure command. LLVM 7 is recommended. Note that LLVM 8 and
+later are *not* supported at this time.
 
 NVC also depends GNU Flex to generate the lexical analyser.
 

m4/ax_llvm_c.m4

@@ -100,6 +100,10 @@ AC_DEFUN([AX_LLVM_C], [
  [LLVM intrinsics have alignment param])
  fi
 
+ if test "$llvm_ver_num" -ge "80"; then
+ AC_MSG_WARN(LLVM 8 and later not yet supported)
+ fi
+
  LLVM_OBJ_EXT="o"
  case $host_os in
  *cygwin*|msys*|mingw32*)