Fix `rustdoc --version` when used with download-rustc

Previously, rustdoc would unconditionally report the version that *rustc* was compiled with.
That showed things like `nightly-2022-10-30`, which wasn't right, since this was a `dev` build compiled from source.

Fix it by changing `rustc_driver::version` to a macro expanded at invocation time.

1 files changed, 32 insertions, 10 deletions

diff --git a/compiler/rustc_driver/src/lib.rs b/compiler/rustc_driver/src/lib.rs
index cf4bcc7c158..03045517703 100644
--- a/compiler/rustc_driver/src/lib.rs
+++ b/compiler/rustc_driver/src/lib.rs
@@ -6,6 +6,7 @@
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(once_cell)]
+#![feature(decl_macro)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
 #![deny(rustc::untranslatable_diagnostic)]
@@ -742,20 +743,41 @@ fn print_crate_info(
 }
 
 /// Prints version information
-pub fn version(binary: &str, matches: &getopts::Matches) {
+///
+/// NOTE: this is a macro to support drivers built at a different time than the main `rustc_driver` crate.
+pub macro version($binary: literal, $matches: expr) {
+    fn unw(x: Option<&str>) -> &str {
+        x.unwrap_or("unknown")
+    }
+    $crate::version_at_macro_invocation(
+        $binary,
+        $matches,
+        unw(option_env!("CFG_VERSION")),
+        unw(option_env!("CFG_VER_HASH")),
+        unw(option_env!("CFG_VER_DATE")),
+        unw(option_env!("CFG_RELEASE")),
+    )
+}
+
+#[doc(hidden)] // use the macro instead
+pub fn version_at_macro_invocation(
+    binary: &str,
+    matches: &getopts::Matches,
+    version: &str,
+    commit_hash: &str,
+    commit_date: &str,
+    release: &str,
+) {
     let verbose = matches.opt_present("verbose");
 
-    println!("{} {}", binary, util::version_str().unwrap_or("unknown version"));
+    println!("{} {}", binary, version);
 
     if verbose {
-        fn unw(x: Option<&str>) -> &str {
-            x.unwrap_or("unknown")
-        }
         println!("binary: {}", binary);
-        println!("commit-hash: {}", unw(util::commit_hash_str()));
-        println!("commit-date: {}", unw(util::commit_date_str()));
+        println!("commit-hash: {}", commit_hash);
+        println!("commit-date: {}", commit_date);
         println!("host: {}", config::host_triple());
-        println!("release: {}", unw(util::release_str()));
+        println!("release: {}", release);
 
         let debug_flags = matches.opt_strs("Z");
         let backend_name = debug_flags.iter().find_map(|x| x.strip_prefix("codegen-backend="));
@@ -1071,7 +1093,7 @@ pub fn handle_options(args: &[String]) -> Option<getopts::Matches> {
     }
 
     if matches.opt_present("version") {
-        version("rustc", &matches);
+        version!("rustc", &matches);
         return None;
     }
 
@@ -1216,7 +1238,7 @@ pub fn report_ice(info: &panic::PanicInfo<'_>, bug_report_url: &str) {
         format!("we would appreciate a bug report: {}", bug_report_url).into(),
         format!(
             "rustc {} running on {}",
-            util::version_str().unwrap_or("unknown_version"),
+            util::version_str!().unwrap_or("unknown_version"),
             config::host_triple()
         )
         .into(),