Auto merge of #108905 - ferrocene:pa-compiletest-ignore, r=ehuss

Validate `ignore` and `only` compiletest directive, and add human-readable ignore reasons

This PR adds strict validation for the `ignore` and `only` compiletest directives, failing if an unknown value is provided to them. Doing so uncovered 79 tests in `tests/ui` that had invalid directives, so this PR also fixes them.

Finally, this PR adds human-readable ignore reasons when tests are ignored due to `ignore` or `only` directives, like *"only executed when the architecture is aarch64"* or *"ignored when the operative system is windows"*. This was the original reason why I started working on this PR and #108659, as we need both of them for Ferrocene.

The PR is a draft because the code is extremely inefficient: it calls `rustc --print=cfg --target $target` for every rustc target (to gather the list of allowed ignore values), which on my system takes between 4s and 5s, and performs a lot of allocations of constant values. I'll fix both of them in the coming days.

r? `@ehuss`

compiler/rustc_driver_impl/src/lib.rs

@@ -44,8 +44,10 @@ use rustc_session::{early_error, early_error_no_abort, early_warn};
 use rustc_span::source_map::{FileLoader, FileName};
 use rustc_span::symbol::sym;
 use rustc_target::json::ToJson;
+use rustc_target::spec::{Target, TargetTriple};
 
 use std::cmp::max;
+use std::collections::BTreeMap;
 use std::env;
 use std::ffi::OsString;
 use std::fs;
@@ -648,6 +650,15 @@ fn print_crate_info(
             TargetSpec => {
                 println!("{}", serde_json::to_string_pretty(&sess.target.to_json()).unwrap());
             }
+            AllTargetSpecs => {
+                let mut targets = BTreeMap::new();
+                for name in rustc_target::spec::TARGETS {
+                    let triple = TargetTriple::from_triple(name);
+                    let target = Target::expect_builtin(&triple);
+                    targets.insert(name, target.to_json());
+                }
+                println!("{}", serde_json::to_string_pretty(&targets).unwrap());
+            }
             FileNames | CrateName => {
                 let Some(attrs) = attrs.as_ref() else {
                     // no crate attributes, print out an error and exit

compiler/rustc_session/src/config.rs

@@ -582,6 +582,7 @@ pub enum PrintRequest {
     CodeModels,
     TlsModels,
     TargetSpec,
+    AllTargetSpecs,
     NativeStaticLibs,
     StackProtectorStrategies,
     LinkArgs,
@@ -1441,8 +1442,8 @@ pub fn rustc_short_optgroups() -> Vec<RustcOptGroup> {
             "Compiler information to print on stdout",
             "[crate-name|file-names|sysroot|target-libdir|cfg|calling-conventions|\
              target-list|target-cpus|target-features|relocation-models|code-models|\
-             tls-models|target-spec-json|native-static-libs|stack-protector-strategies|\
-             link-args]",
+             tls-models|target-spec-json|all-target-specs-json|native-static-libs|\
+             stack-protector-strategies|link-args]",
         ),
         opt::flagmulti_s("g", "", "Equivalent to -C debuginfo=2"),
         opt::flagmulti_s("O", "", "Equivalent to -C opt-level=2"),
@@ -1889,6 +1890,7 @@ fn collect_print_requests(
         ("native-static-libs", PrintRequest::NativeStaticLibs),
         ("stack-protector-strategies", PrintRequest::StackProtectorStrategies),
         ("target-spec-json", PrintRequest::TargetSpec),
+        ("all-target-specs-json", PrintRequest::AllTargetSpecs),
         ("link-args", PrintRequest::LinkArgs),
         ("split-debuginfo", PrintRequest::SplitDebuginfo),
     ];
@@ -1902,7 +1904,18 @@ fn collect_print_requests(
                     early_error(
                         error_format,
                         "the `-Z unstable-options` flag must also be passed to \
-                     enable the target-spec-json print option",
+                         enable the target-spec-json print option",
+                    );
+                }
+            }
+            Some((_, PrintRequest::AllTargetSpecs)) => {
+                if unstable_opts.unstable_options {
+                    PrintRequest::AllTargetSpecs
+                } else {
+                    early_error(
+                        error_format,
+                        "the `-Z unstable-options` flag must also be passed to \
+                         enable the all-target-specs-json print option",
                     );
                 }
             }

src/bootstrap/test.rs

@@ -694,7 +694,7 @@ impl Step for CompiletestTest {
     /// Runs `cargo test` for compiletest.
     fn run(self, builder: &Builder<'_>) {
         let host = self.host;
-        let compiler = builder.compiler(0, host);
+        let compiler = builder.compiler(1, host);
 
         // We need `ToolStd` for the locally-built sysroot because
         // compiletest uses unstable features of the `test` crate.