Add parallel-front-end directive.

Author: ywxt

src/tools/compiletest/src/directives.rs

@@ -205,6 +205,8 @@ pub struct TestProps {
     pub dont_require_annotations: HashSet<ErrorKind>,
     /// Whether pretty printers should be disabled in gdb.
     pub disable_gdb_pretty_printers: bool,
+    /// Whether to use the parallel front end.
+    pub parallel_front_end: bool,
 }
 
 mod directives {
@@ -254,6 +256,7 @@ mod directives {
     // This isn't a real directive, just one that is probably mistyped often
     pub const INCORRECT_COMPILER_FLAGS: &'static str = "compiler-flags";
     pub const DISABLE_GDB_PRETTY_PRINTERS: &'static str = "disable-gdb-pretty-printers";
+    pub const PARALLEL_FRONT_END: &'static str = "parallel-front-end";
 }
 
 impl TestProps {
@@ -310,6 +313,7 @@ impl TestProps {
             add_core_stubs: false,
             dont_require_annotations: Default::default(),
             disable_gdb_pretty_printers: false,
+            parallel_front_end: false,
         }
     }
 
@@ -664,6 +668,7 @@ impl TestProps {
                         DISABLE_GDB_PRETTY_PRINTERS,
                         &mut self.disable_gdb_pretty_printers,
                     );
+                    config.set_name_directive(ln, PARALLEL_FRONT_END, &mut self.parallel_front_end);
                 },
             );
 

src/tools/compiletest/src/directives/directive_names.rs

@@ -239,6 +239,7 @@ pub(crate) const KNOWN_DIRECTIVE_NAMES: &[&str] = &[
     "only-x86_64-pc-windows-gnu",
     "only-x86_64-pc-windows-msvc",
     "only-x86_64-unknown-linux-gnu",
+    "parallel-front-end",
     "pp-exact",
     "pretty-compare-only",
     "pretty-mode",

src/tools/compiletest/src/runtest.rs

@@ -1520,8 +1520,10 @@ impl<'test> TestCx<'test> {
         };
         rustc.arg(input_file);
 
-        // Use a single thread for efficiency and a deterministic error message order
-        rustc.arg("-Zthreads=1");
+        if !self.props.parallel_front_end {
+            // Use a single thread for efficiency and a deterministic error message order
+            rustc.arg("-Zthreads=1");
+        }
 
         // Hide libstd sources from ui tests to make sure we generate the stderr
         // output that users will see.
@@ -2749,7 +2751,7 @@ impl<'test> TestCx<'test> {
         // Wrapper tools set by `runner` might provide extra output on failure,
         // for example a WebAssembly runtime might print the stack trace of an
         // `unreachable` instruction by default.
-        let compare_output_by_lines = self.config.runner.is_some();
+        let compare_output_by_lines = self.props.parallel_front_end || self.config.runner.is_some();
 
         let tmp;
         let (expected, actual): (&str, &str) = if compare_output_by_lines {

tests/ui/parallel-rustc/cache-after-waiting-issue-111528.rs

@@ -1,16 +1,18 @@
+// Test for #111528, the ice issue cause waiting on a query that panicked
+//
 //@ compile-flags: -Z threads=16
 //@ build-fail
+//@ parallel-front-end
 
-#![crate_type="rlib"]
+#![crate_type = "rlib"]
 #![allow(warnings)]
 
-#[export_name="fail"]
-pub fn a() {
-}
+#[export_name = "fail"]
+pub fn a() {}
 
-#[export_name="fail"]
+#[export_name = "fail"]
 pub fn b() {
-//~^ ERROR symbol `fail` is already defined
+    //~^ ERROR symbol `fail` is already defined
 }
 
 fn main() {}

tests/ui/parallel-rustc/cache-after-waiting-issue-111528.stderr

@@ -1,5 +1,5 @@
 error: symbol `fail` is already defined
-  --> $DIR/cache-after-waiting-issue-111528.rs:12:1
+  --> $DIR/cache-after-waiting-issue-111528.rs:14:1
    |
 LL | pub fn b() {
    | ^^^^^^^^^^

tests/ui/parallel-rustc/cycle_crash.rs

@@ -1,5 +1,7 @@
 //@ compile-flags: -Z threads=2
+//@ check-fail
+//@ parallel-front-end
 
-const FOO: usize = FOO; //~ERROR cycle detected when simplifying constant for the type system `FOO`
+const FOO: usize = FOO; //~ ERROR cycle detected when simplifying constant for the type system `FOO`
 
 fn main() {}

tests/ui/parallel-rustc/cycle_crash.stderr

@@ -1,11 +1,11 @@
 error[E0391]: cycle detected when simplifying constant for the type system `FOO`
-  --> $DIR/cycle_crash.rs:3:1
+  --> $DIR/cycle_crash.rs:5:1
    |
 LL | const FOO: usize = FOO;
    | ^^^^^^^^^^^^^^^^
    |
 note: ...which requires const-evaluating + checking `FOO`...
-  --> $DIR/cycle_crash.rs:3:20
+  --> $DIR/cycle_crash.rs:5:20
    |
 LL | const FOO: usize = FOO;
    |                    ^^^

tests/ui/parallel-rustc/export-symbols-deadlock-issue-118205-2.rs

@@ -1,6 +1,10 @@
+// Test for #118205, which causes a deadlock bug
+//
 //@ compile-flags:-C extra-filename=-1 -Z threads=16
 //@ no-prefer-dynamic
 //@ build-pass
+//@ parallel-front-end
+
 #![crate_name = "crateresolve1"]
 #![crate_type = "lib"]
 

tests/ui/parallel-rustc/export-symbols-deadlock-issue-118205.rs

@@ -1,5 +1,8 @@
+// Test for #118205, which causes a deadlock bug
+//
 //@ compile-flags: -Z threads=16
 //@ build-pass
+//@ parallel-front-end
 
 pub static GLOBAL: isize = 3;
 

tests/ui/parallel-rustc/hello_world.rs

@@ -1,5 +1,8 @@
+// Test for the basic function of parallel front end
+//
 //@ compile-flags: -Z threads=8
 //@ run-pass
+//@ parallel-front-end
 
 fn main() {
     println!("Hello world!");