compiletest: crashes: turn off backtraces for faster tests

Author: matthiaskrgr

src/tools/compiletest/src/header.rs

@@ -581,6 +581,16 @@ impl TestProps {
             self.incremental = true;
         }
 
+        if config.mode == Mode::Crashes {
+            // we don't want to pollute anything with backtrace-files
+            // also turn off backtraces in order to save some execution
+            // time on the tests; we only need to know IF it crashes
+            self.rustc_env = vec![
+                ("RUST_BACKTRACE".to_string(), "0".to_string()),
+                ("RUSTC_ICE".to_string(), "0".to_string()),
+            ];
+        }
+
         for key in &["RUST_TEST_NOCAPTURE", "RUST_TEST_THREADS"] {
             if let Ok(val) = env::var(key) {
                 if self.exec_env.iter().find(|&&(ref x, _)| x == key).is_none() {
@@ -596,7 +606,8 @@ impl TestProps {
 
     fn update_fail_mode(&mut self, ln: &str, config: &Config) {
         let check_ui = |mode: &str| {
-            if config.mode != Mode::Ui {
+            // Mode::Crashes may need build-fail in order to trigger llvm errors or stack overflows
+            if config.mode != Mode::Ui && config.mode != Mode::Crashes {
                 panic!("`{}-fail` header is only supported in UI tests", mode);
             }
         };
@@ -625,7 +636,7 @@ impl TestProps {
     fn update_pass_mode(&mut self, ln: &str, revision: Option<&str>, config: &Config) {
         let check_no_run = |s| match (config.mode, s) {
             (Mode::Ui, _) => (),
-            (Mode::Crashes, "should-ice") => (),
+            (Mode::Crashes, _) => (),
             (Mode::Codegen, "build-pass") => (),
             (Mode::Incremental, _) => {
                 if revision.is_some() && !self.revisions.iter().all(|r| r.starts_with("cfail")) {