rustc: implement argsfiles for command line

This makes `rustc` support `@path` arguments on the command line. The `path` is opened and the file is interpreted
as new command line options which are logically inserted at that point in the command-line. The options in the file
are one per line. The file is UTF-8 encoded, and may have either Unix or Windows line endings.
It does not support recursive use of `@path`.

This is useful for very large command lines, or when command-lines are being generated into files by other tooling.

1 files changed, 16 insertions, 0 deletions

diff --git a/src/test/ui/commandline-argfile-missing.rs b/src/test/ui/commandline-argfile-missing.rs
new file mode 100644
index 00000000000..34faf076335
--- /dev/null
+++ b/src/test/ui/commandline-argfile-missing.rs
@@ -0,0 +1,16 @@
+// Check to see if we can get parameters from an @argsfile file
+//
+// build-fail
+// normalize-stderr-test: "Argument \d+" -> "Argument $$N"
+// normalize-stderr-test: "os error \d+" -> "os error $$ERR"
+// normalize-stderr-test: "commandline-argfile-missing.args:[^(]*" -> "commandline-argfile-missing.args: $$FILE_MISSING "
+// compile-flags: --cfg cmdline_set @{{src-base}}/commandline-argfile-missing.args
+
+#[cfg(not(cmdline_set))]
+compile_error!("cmdline_set not set");
+
+#[cfg(not(unbroken))]
+compile_error!("unbroken not set");
+
+fn main() {
+}