From 72cd8aedc2901d6a6b598eadc001cc39040ae487 Mon Sep 17 00:00:00 2001

From: Josh Stone <jistone@redhat.com>

Date: Wed, 12 Dec 2018 16:51:31 -0800

Subject: [PATCH] Try to get the target triple from rustc itself

The prior method was trying to pick the triple out of the sysroot path.

A FIXME comment already notes that this doesn't work with custom

toolchains in rustup. It also fails with distro-installed toolchains,

where the sysroot may simply be `/usr`.

The output of `rustc -Vv` is a more reliable source, as it contains a

line like `host: x86_64-unknown-linux-gnu`.  This should be enough to

identify the triple for any `rustc`, but just in case, the path-based

code is kept as a fallback.

---

 src/loader.rs | 41 ++++++++++++++++++++++++++++++++++++++---

 1 file changed, 38 insertions(+), 3 deletions(-)

diff --git a/src/loader.rs b/src/loader.rs

index 645c95139164..fe92bef1c596 100644

--- a/src/loader.rs

+++ b/src/loader.rs

@@ -108,9 +108,33 @@ impl AnalysisLoader for CargoAnalysisLoader {

     }

 }

+fn extract_target_triple(sys_root_path: &Path) -> String {

+    // First try to get the triple from the rustc version output,

+    // otherwise fall back on the rustup-style toolchain path.

+    extract_rustc_host_triple()

+        .unwrap_or_else(|| extract_rustup_target_triple(sys_root_path))

+}

+

+fn extract_rustc_host_triple() -> Option<String> {

+    let rustc = env::var("RUSTC").unwrap_or(String::from("rustc"));

+    let verbose_version = Command::new(rustc)

+        .arg("--verbose")

+        .arg("--version")

+        .output()

+        .ok()

+        .and_then(|out| String::from_utf8(out.stdout).ok())?;

+

+    // Extracts the triple from a line like `host: x86_64-unknown-linux-gnu`

+    verbose_version

+        .lines()

+        .find(|line| line.starts_with("host: "))

+        .and_then(|host| host.split_whitespace().nth(1))

+        .map(String::from)

+}

+

 // FIXME: This can fail when using a custom toolchain in rustup (often linked to

 // `/$rust_repo/build/$target/stage2`)

-fn extract_target_triple(sys_root_path: &Path) -> String {

+fn extract_rustup_target_triple(sys_root_path: &Path) -> String {

     // Extracts nightly-x86_64-pc-windows-msvc from

     // $HOME/.rustup/toolchains/nightly-x86_64-pc-windows-msvc

     let toolchain = sys_root_path

@@ -169,7 +193,7 @@ mod tests {

             r#"C:\Users\user\.rustup\toolchains\nightly-x86_64-pc-windows-msvc"#,

         );

         assert_eq!(

-            extract_target_triple(path),

+            extract_rustup_target_triple(path),

             String::from("x86_64-pc-windows-msvc")

         );

     }

@@ -180,8 +204,19 @@ mod tests {

             "/home/user/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu",

         );

         assert_eq!(

-            extract_target_triple(path),

+            extract_rustup_target_triple(path),

             String::from("x86_64-unknown-linux-gnu")

         );

     }

+

+    #[test]

+    fn target_triple() {

+        let sys_root_path = sys_root_path();

+        let target_triple = extract_target_triple(&sys_root_path);

+        let target_path = sys_root_path

+            .join("lib")

+            .join("rustlib")

+            .join(&target_triple);

+        assert!(target_path.is_dir(), "{:?} is not a directory!", target_path);

+    }

 }

-- 

2.19.2