From 389b7ff19074988a3855bbc5ba7b19eb903a6fb4 Mon Sep 17 00:00:00 2001
From: Mark Rousskov <mark.simulacrum@gmail.com>
Date: Wed, 16 Sep 2020 17:57:20 -0400
Subject: [PATCH] Do not link LLVM tools to LLVM dylib unless rustc is

Previously we would have some platforms where LLVM was linked to rustc
statically, but to the LLVM tools dynamically. That meant we were distributing
two copies of LLVM: one as a separate dylib and one statically linked in to
librustc_driver.
---
 src/bootstrap/dist.rs   | 13 +++++--------
 src/bootstrap/native.rs | 11 ++++++++---
 src/ci/run.sh           |  7 -------
 3 files changed, 13 insertions(+), 18 deletions(-)

diff --git a/src/bootstrap/dist.rs b/src/bootstrap/dist.rs
index debe6e36a9b..044507c398f 100644
--- a/src/bootstrap/dist.rs
+++ b/src/bootstrap/dist.rs
@@ -2401,14 +2401,11 @@ fn maybe_install_llvm(builder: &Builder<'_>, target: TargetSelection, dst_libdir
         return;
     }
 
-    // On macOS for some reason the llvm-config binary behaves differently and
-    // and fails on missing .a files if run without --link-shared. If run with
-    // that option, it still fails, but because we only ship a libLLVM.dylib
-    // rather than libLLVM-11-rust-....dylib file.
-    //
-    // For now just don't use llvm-config here on macOS; that will fail to
-    // support CI-built LLVM, but until we work out the different behavior that
-    // is fine as it is off by default.
+    // On macOS, rustc (and LLVM tools) link to an unversioned libLLVM.dylib
+    // instead of libLLVM-11-rust-....dylib, as on linux. It's not entirely
+    // clear why this is the case, though. llvm-config will emit the versioned
+    // paths and we don't want those in the sysroot (as we're expecting
+    // unversioned paths).
     if target.contains("apple-darwin") {
         let src_libdir = builder.llvm_out(target).join("lib");
         let llvm_dylib_path = src_libdir.join("libLLVM.dylib");
diff --git a/src/bootstrap/native.rs b/src/bootstrap/native.rs
index 3829d47da33..71b35c0433a 100644
--- a/src/bootstrap/native.rs
+++ b/src/bootstrap/native.rs
@@ -129,8 +129,10 @@ impl Step for Llvm {
                 Err(m) => m,
             };
 
-        if builder.config.llvm_link_shared && target.contains("windows") {
-            panic!("shared linking to LLVM is not currently supported on Windows");
+        if builder.config.llvm_link_shared
+            && (target.contains("windows") || target.contains("apple-darwin"))
+        {
+            panic!("shared linking to LLVM is not currently supported on {}", target.triple);
         }
 
         builder.info(&format!("Building LLVM for {}", target));
@@ -209,7 +211,10 @@ impl Step for Llvm {
         // which saves both memory during parallel links and overall disk space
         // for the tools. We don't do this on every platform as it doesn't work
         // equally well everywhere.
-        if builder.llvm_link_tools_dynamically(target) {
+        //
+        // If we're not linking rustc to a dynamic LLVM, though, then don't link
+        // tools to it.
+        if builder.llvm_link_tools_dynamically(target) && builder.config.llvm_link_shared {
             cfg.define("LLVM_LINK_LLVM_DYLIB", "ON");
         }
 
diff --git a/src/ci/run.sh b/src/ci/run.sh
index c8faf1ec831..5231aa2e766 100755
--- a/src/ci/run.sh
+++ b/src/ci/run.sh
@@ -75,13 +75,6 @@ if [ "$DEPLOY$DEPLOY_ALT" = "1" ]; then
   RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --set rust.remap-debuginfo"
   RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --debuginfo-level-std=1"
 
-  # If we're distributing binaries, we want a shared LLVM link. We're already
-  # going to link LLVM to the LLVM tools dynamically, so we need to ship a
-  # libLLVM library anyway.
-  if !isWindows; then
-    RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --set llvm.link-shared=true"
-  fi
-
   if [ "$NO_LLVM_ASSERTIONS" = "1" ]; then
     RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --disable-llvm-assertions"
   elif [ "$DEPLOY_ALT" != "" ]; then