Rollup merge of rust-lang#51977 - mnd:fix-bootstrap-test-with-local-stage0, r=simulacrum

bootstrap: tests should use rustc from config.toml

Tests should always use "rustc" and "cargo" from config.toml instead of assuming that stage0 binaries was downloaded to build directory.

Without this change `./x.py test src/bootstrap` will always try to use `build/ARCH/stage0/bin/rustc` file as compiler, but when we use local compiler to bootstrap this file does not exist.

Author: pietroalbini

src/bootstrap/bootstrap.py

@@ -816,6 +816,8 @@ def bootstrap(help_triggered):
     env["BOOTSTRAP_PYTHON"] = sys.executable
     env["BUILD_DIR"] = build.build_dir
     env["RUSTC_BOOTSTRAP"] = '1'
+    env["CARGO"] = build.cargo()
+    env["RUSTC"] = build.rustc()
     run(args, env=env, verbose=build.verbose)
 
 

src/bootstrap/config.rs

@@ -23,7 +23,6 @@ use std::cmp;
 
 use num_cpus;
 use toml;
-use util::exe;
 use cache::{INTERNER, Interned};
 use flags::Flags;
 pub use flags::Subcommand;
@@ -367,9 +366,8 @@ impl Config {
         config.src = Config::path_from_python("SRC");
         config.out = Config::path_from_python("BUILD_DIR");
 
-        let stage0_root = config.out.join(&config.build).join("stage0/bin");
-        config.initial_rustc = stage0_root.join(exe("rustc", &config.build));
-        config.initial_cargo = stage0_root.join(exe("cargo", &config.build));
+        config.initial_rustc = Config::path_from_python("RUSTC");
+        config.initial_cargo = Config::path_from_python("CARGO");
 
         config
     }