Rollup merge of #137096 - ehuss:stabilize-doctest-xcompile, r=fmease

Stabilize flags for doctest cross compilation

This makes the following changes in preparation for supporting doctest cross-compiling in cargo:

- Renames `--runtool` and `--runtool-arg` to `--test-runtool` and `--test-runtool-arg` to maintain consistency with other `--test-*` arguments.
- Stabilizes the `--test-runtool` and `--test-runtool-arg`. These are needed in order to support cargo's `target.runner` option which specifies a runner to execute a cross-compiled doctest (for example, qemu).
- Stabilizes the `--enable-per-target-ignores` flag by removing it and making it unconditionally enabled. This makes it possible to disable a doctest on a per-target basis, which I think will be helpful for rolling out this feature.

These changes were suggested in https://rust-lang.zulipchat.com/#narrow/channel/266220-t-rustdoc/topic/stabilizing.20doctest.20xcompile/near/409281127

The intent is to stabilize the doctest-xcompile feature in cargo. This will help ensure that for projects that do cross-compile testing that their doctests are also covered. Currently there is a somewhat surprising behavior that they are ignored.

Closes rust-lang/rust#64245

try-job: x86_64-msvc-1

Author: matthiaskrgr

cargo-miri/src/main.rs

@@ -53,7 +53,7 @@ fn main() {
     //     with `RustcPhase::Rustdoc`. There we perform a check-build (needed to get the expected
     //     build failures for `compile_fail` doctests) and then store a JSON file with the
     //     information needed to run this test.
-    //   - We also set `--runtool` to ourselves, which ends up in `phase_runner` with
+    //   - We also set `--test-runtool` to ourselves, which ends up in `phase_runner` with
     //     `RunnerPhase::Rustdoc`. There we parse the JSON file written in `phase_rustc` and invoke
     //     the Miri driver for interpretation.
 

cargo-miri/src/phases.rs

@@ -666,8 +666,8 @@ pub fn phase_rustdoc(mut args: impl Iterator<Item = String>) {
         if arg == "--extern" {
             // Patch --extern arguments to use *.rmeta files, since phase_cargo_rustc only creates stub *.rlib files.
             forward_patched_extern_arg(&mut args, &mut cmd);
-        } else if arg == "--runtool" {
-            // An existing --runtool flag indicates cargo is running in cross-target mode, which we don't support.
+        } else if arg == "--test-runtool" {
+            // An existing --test-runtool flag indicates cargo is running in cross-target mode, which we don't support.
             // Note that this is only passed when cargo is run with the unstable -Zdoctest-xcompile flag;
             // otherwise, we won't be called as rustdoc at all.
             show_error!("cross-interpreting doctests is not currently supported by Miri.");
@@ -693,8 +693,8 @@ pub fn phase_rustdoc(mut args: impl Iterator<Item = String>) {
     // to let phase_cargo_rustc know to expect that. We'll use this environment variable as a flag:
     cmd.env("MIRI_CALLED_FROM_RUSTDOC", "1");
 
-    // The `--test-builder` and `--runtool` arguments are unstable rustdoc features,
-    // which are disabled by default. We first need to enable them explicitly:
+    // The `--test-builder` is an unstable rustdoc features,
+    // which is disabled by default. We first need to enable them explicitly:
     cmd.arg("-Zunstable-options");
 
     // rustdoc needs to know the right sysroot.
@@ -705,7 +705,7 @@ pub fn phase_rustdoc(mut args: impl Iterator<Item = String>) {
     // Make rustdoc call us back.
     let cargo_miri_path = env::current_exe().expect("current executable path invalid");
     cmd.arg("--test-builder").arg(&cargo_miri_path); // invoked by forwarding most arguments
-    cmd.arg("--runtool").arg(&cargo_miri_path); // invoked with just a single path argument
+    cmd.arg("--test-runtool").arg(&cargo_miri_path); // invoked with just a single path argument
 
     debug_cmd("[cargo-miri rustdoc]", verbose, &cmd);
     exec(cmd)