Avoid runtime dependency on static libstdc++

Usually, we do want to use the static C++ library when building rustc_llvm, but do not want to have that dependency at compiler runtime. Change the defaults to Make It So.

2 files changed, 5 insertions, 1 deletions

diff --git a/src/bootstrap/config.rs b/src/bootstrap/config.rs
index ba50ce9ec24..2afce4fac42 100644
--- a/src/bootstrap/config.rs
+++ b/src/bootstrap/config.rs
@@ -781,7 +781,7 @@ impl Config {
         config.llvm_optimize = true;
         config.ninja_in_file = true;
         config.llvm_version_check = true;
-        config.llvm_static_stdcpp = true;
+        config.llvm_static_stdcpp = false;
         config.backtrace = true;
         config.rust_optimize = true;
         config.rust_optimize_tests = true;
diff --git a/src/ci/run.sh b/src/ci/run.sh
index 9a247fb60a8..7de06ec35c3 100755
--- a/src/ci/run.sh
+++ b/src/ci/run.sh
@@ -123,6 +123,10 @@ else
   # (And PGO is its own can of worms).
   if [ "$NO_DOWNLOAD_CI_LLVM" = "" ]; then
     RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --set llvm.download-ci-llvm=if-available"
+  else
+    # When building for CI we want to use the static C++ Standard library
+    # included with LLVM, since a dynamic libstdcpp may not be available.
+    RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --set llvm.static-libstdcpp"
   fi
 fi