From c090e1729badfcdda072026319814450c293e74c Mon Sep 17 00:00:00 2001
From: Richard Feldman <oss@rtfeldman.com>
Date: Mon, 7 Jun 2021 21:51:28 -0400
Subject: [PATCH] Update macOS installation instructions

---
 BUILDING_FROM_SOURCE.md | 24 +++++-------------------
 1 file changed, 5 insertions(+), 19 deletions(-)

diff --git a/BUILDING_FROM_SOURCE.md b/BUILDING_FROM_SOURCE.md
index 0bbd5fdda8..af1e8b7e0d 100644
--- a/BUILDING_FROM_SOURCE.md
+++ b/BUILDING_FROM_SOURCE.md
@@ -54,13 +54,15 @@ If you want to install it manually, you can also download Zig directly [here](ht
 ### LLVM
 **version: 12.0.x**
 
+For macOS, you can install LLVM 12 using `brew install llvm@12` and then adding
+`/usr/local/opt/llvm/bin` to your `PATH`. You can confirm this worked by
+running `llc --version` - it should mention "LLVM version 12.0.0" at the top.
+
 For Ubuntu and Debian, you can use the `Automatic installation script` at [apt.llvm.org](https://apt.llvm.org):
 ```
 sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)"
 ```
 
-For macOS, check the troubleshooting section below.
-
 There are also plenty of alternative options at http://releases.llvm.org/download.html
 
 ## Using Nix
@@ -143,31 +145,15 @@ If you encounter `cannot find -lz` run `sudo apt install zlib1g-dev`.
 
 ### LLVM installation on macOS
 
-By default homebrew will try to install llvm 11, which is currently
-unsupported. You need to install an older version (10.0.0_3) by doing:
-
-```
-$ brew edit llvm
-
-# Replace the contents of the file with https://raw.githubusercontent.com/Homebrew/homebrew-core/6616d50fb0b24dbe30f5e975210bdad63257f517/Formula/llvm.rb
-
-# we expect llvm-as-10 to be present
-$ ln -s /usr/local/opt/llvm/bin/{llvm-as,llvm-as-10}
-
-# "pinning" ensures that homebrew doesn't update it automatically
-$ brew pin llvm
-```
+If installing LLVM fails, it might help to run `sudo xcode-select -r` before installing again.
 
 It might also be useful to add these exports to your shell:
 
 ```
-export PATH="/usr/local/opt/llvm/bin:$PATH"
 export LDFLAGS="-L/usr/local/opt/llvm/lib -Wl,-rpath,/usr/local/opt/llvm/lib"
 export CPPFLAGS="-I/usr/local/opt/llvm/include"
 ```
 
-If installing LLVM still fails, it might help to run `sudo xcode-select -r` before installing again.
-
 ### LLVM installation on Windows
 
 Installing LLVM's prebuilt binaries doesn't seem to be enough for the `llvm-sys` crate that Roc depends on, so I had to build LLVM from source