compiletest: Support running with a remapped base directory.

src/tools/compiletest/src/header.rs

@@ -162,6 +162,9 @@ pub struct TestProps {
     pub stderr_per_bitwidth: bool,
     // The MIR opt to unit test, if any
     pub mir_unit_test: Option<String>,
+    // Whether to tell `rustc` to remap the "src base" directory to a fake
+    // directory.
+    pub remap_src_base: bool,
 }
 
 mod directives {
@@ -196,6 +199,7 @@ mod directives {
     pub const INCREMENTAL: &'static str = "incremental";
     pub const KNOWN_BUG: &'static str = "known-bug";
     pub const MIR_UNIT_TEST: &'static str = "unit-test";
+    pub const REMAP_SRC_BASE: &'static str = "remap-src-base";
     // This isn't a real directive, just one that is probably mistyped often
     pub const INCORRECT_COMPILER_FLAGS: &'static str = "compiler-flags";
 }
@@ -241,6 +245,7 @@ impl TestProps {
             should_ice: false,
             stderr_per_bitwidth: false,
             mir_unit_test: None,
+            remap_src_base: false,
         }
     }
 
@@ -433,6 +438,7 @@ impl TestProps {
                 config.set_name_value_directive(ln, MIR_UNIT_TEST, &mut self.mir_unit_test, |s| {
                     s.trim().to_string()
                 });
+                config.set_name_directive(ln, REMAP_SRC_BASE, &mut self.remap_src_base);
             });
         }
 

src/tools/compiletest/src/runtest.rs

@@ -44,6 +44,8 @@ use debugger::{check_debugger_output, DebuggerCommands};
 #[cfg(test)]
 mod tests;
 
+const FAKE_SRC_BASE: &str = "fake-test-src-base";
+
 #[cfg(windows)]
 fn disable_error_reporting<F: FnOnce() -> R, R>(f: F) -> R {
     use std::sync::Mutex;
@@ -1328,12 +1330,19 @@ impl<'test> TestCx<'test> {
             return;
         }
 
+        // On Windows, translate all '\' path separators to '/'
+        let file_name = format!("{}", self.testpaths.file.display()).replace(r"\", "/");
+
         // On Windows, keep all '\' path separators to match the paths reported in the JSON output
         // from the compiler
-        let os_file_name = self.testpaths.file.display().to_string();
+        let diagnostic_file_name = if self.props.remap_src_base {
-
+            let mut p = PathBuf::from(FAKE_SRC_BASE);
-        // on windows, translate all '\' path separators to '/'
+            p.push(&self.testpaths.relative_dir);
-        let file_name = format!("{}", self.testpaths.file.display()).replace(r"\", "/");
+            p.push(self.testpaths.file.file_name().unwrap());
+            p.display().to_string()
+        } else {
+            self.testpaths.file.display().to_string()
+        };
 
         // If the testcase being checked contains at least one expected "help"
         // message, then we'll ensure that all "help" messages are expected.
@@ -1343,7 +1352,7 @@ impl<'test> TestCx<'test> {
         let expect_note = expected_errors.iter().any(|ee| ee.kind == Some(ErrorKind::Note));
 
         // Parse the JSON output from the compiler and extract out the messages.
-        let actual_errors = json::parse_output(&os_file_name, &proc_res.stderr, proc_res);
+        let actual_errors = json::parse_output(&diagnostic_file_name, &proc_res.stderr, proc_res);
         let mut unexpected = Vec::new();
         let mut found = vec![false; expected_errors.len()];
         for actual_error in &actual_errors {
@@ -1970,6 +1979,14 @@ impl<'test> TestCx<'test> {
             }
         }
 
+        if self.props.remap_src_base {
+            rustc.arg(format!(
+                "--remap-path-prefix={}={}",
+                self.config.src_base.display(),
+                FAKE_SRC_BASE,
+            ));
+        }
+
         match emit {
             Emit::None => {}
             Emit::Metadata if is_rustdoc => {}
@@ -3545,6 +3562,14 @@ impl<'test> TestCx<'test> {
         let parent_dir = self.testpaths.file.parent().unwrap();
         normalize_path(parent_dir, "$DIR");
 
+        if self.props.remap_src_base {
+            let mut remapped_parent_dir = PathBuf::from(FAKE_SRC_BASE);
+            if self.testpaths.relative_dir != Path::new("") {
+                remapped_parent_dir.push(&self.testpaths.relative_dir);
+            }
+            normalize_path(&remapped_parent_dir, "$DIR");
+        }
+
         let source_bases = &[
             // Source base on the current filesystem (calculated as parent of `tests/$suite`):
             Some(self.config.src_base.parent().unwrap().parent().unwrap().into()),