Rollup merge of #82261 - ojeda:rustdoc-argfile, r=jyn514

rustdoc: Support argument files

Factors out the `rustc_driver` logic that handles argument files so that rustdoc supports them as well, e.g.:

    rustdoc `@argfile`

This is needed to be able to generate docs for projects that already use argument files when compiling them, e.g. projects that pass a huge number of `--cfg` arguments.

The feature was stabilized for `rustc` in #66172.

1 files changed, 13 insertions, 0 deletions

diff --git a/src/test/rustdoc-ui/commandline-argfile.rs b/src/test/rustdoc-ui/commandline-argfile.rs
new file mode 100644
index 00000000000..cc8c8722c1c
--- /dev/null
+++ b/src/test/rustdoc-ui/commandline-argfile.rs
@@ -0,0 +1,13 @@
+// Check to see if we can get parameters from an @argsfile file
+//
+// check-pass
+// compile-flags: --cfg cmdline_set @{{src-base}}/commandline-argfile.args
+
+#[cfg(not(cmdline_set))]
+compile_error!("cmdline_set not set");
+
+#[cfg(not(unbroken))]
+compile_error!("unbroken not set");
+
+fn main() {
+}