Merge branch 'master' into master

1 files changed, 13 insertions, 0 deletions

diff --git a/src/bootstrap/tool.rs b/src/bootstrap/tool.rs
index bfb846f3b56..f9be35d7c5e 100644
--- a/src/bootstrap/tool.rs
+++ b/src/bootstrap/tool.rs
@@ -513,6 +513,19 @@ impl Step for Rustdoc {
         // rustc compiler it's paired with, so it must be built with the previous stage compiler.
         let build_compiler = builder.compiler(target_compiler.stage - 1, builder.config.build);
 
+        // When using `download-rustc` and a stage0 build_compiler, copying rustc doesn't actually
+        // build stage0 libstd (because the libstd in sysroot has the wrong ABI). Explicitly build
+        // it.
+        builder.ensure(compile::Std { compiler: build_compiler, target: target_compiler.host });
+        builder.ensure(compile::Rustc { compiler: build_compiler, target: target_compiler.host });
+        // NOTE: this implies that `download-rustc` is pretty useless when compiling with the stage0
+        // compiler, since you do just as much work.
+        if !builder.config.dry_run && builder.config.download_rustc && build_compiler.stage == 0 {
+            println!(
+                "warning: `download-rustc` does nothing when building stage1 tools; consider using `--stage 2` instead"
+            );
+        }
+
         // The presence of `target_compiler` ensures that the necessary libraries (codegen backends,
         // compiler libraries, ...) are built. Rustdoc does not require the presence of any
         // libraries within sysroot_libdir (i.e., rustlib), though doctests may want it (since