Rollup merge of rust-lang#112454 - ferrocene:pa-compiletest-dynamic-l…

…inking, r=davidtwco

Make compiletest aware of targets without dynamic linking

Some parts of the compiletest internals and some tests require dynamic linking to work, which is not supported by all targets. Before this PR, this was handled by if branches matching on the target name.

This PR loads whether a target supports dynamic linking or not from the target spec, and adds a `// needs-dynamic-linking` attribute for tests that require it. Note that I was not able to replace all the old conditions based on the target name, as some targets have `dynamic_linking: true` in their spec but pretend they don't have it in compiletest.

Also, to get this to work I had to *partially* revert rust-lang#111472 (cc `@djkoloski` `@tmandry` `@bjorn3).` On one hand, only the target spec contains whether a target supports dynamic linking, but on the other hand a subset of the fields can be overridden through `-C` flags (as far as I'm aware only `-C panic=$strategy`). The solution I came up with is to take the target spec as the base, and then override the panic strategy based on `--print=cfg`. Hopefully that should not break y'all again.

src/tools/compiletest/src/common.rs

@@ -453,7 +453,7 @@ impl TargetCfgs {
         let mut all_families = HashSet::new();
         let mut all_pointer_widths = HashSet::new();
 
-        for (target, cfg) in targets.into_iter() {
+        for (target, cfg) in targets.iter() {
             all_archs.insert(cfg.arch.clone());
             all_oses.insert(cfg.os.clone());
             all_oses_and_envs.insert(cfg.os_and_env());
@@ -464,11 +464,11 @@ impl TargetCfgs {
             }
             all_pointer_widths.insert(format!("{}bit", cfg.pointer_width));
 
-            all_targets.insert(target.into());
+            all_targets.insert(target.clone());
         }
 
         Self {
-            current: Self::get_current_target_config(config),
+            current: Self::get_current_target_config(config, &targets),
             all_targets,
             all_archs,
             all_oses,
@@ -480,16 +480,20 @@ impl TargetCfgs {
         }
     }
 
-    fn get_current_target_config(config: &Config) -> TargetCfg {
-        let mut arch = None;
-        let mut os = None;
-        let mut env = None;
-        let mut abi = None;
-        let mut families = Vec::new();
-        let mut pointer_width = None;
-        let mut endian = None;
-        let mut panic = None;
-
+    fn get_current_target_config(
+        config: &Config,
+        targets: &HashMap<String, TargetCfg>,
+    ) -> TargetCfg {
+        let mut cfg = targets[&config.target].clone();
+
+        // To get the target information for the current target, we take the target spec obtained
+        // from `--print=all-target-specs-json`, and then we enrich it with the information
+        // gathered from `--print=cfg --target=$target`.
+        //
+        // This is done because some parts of the target spec can be overridden with `-C` flags,
+        // which are respected for `--print=cfg` but not for `--print=all-target-specs-json`. The
+        // code below extracts them from `--print=cfg`: make sure to only override fields that can
+        // actually be changed with `-C` flags.
         for config in
             rustc_output(config, &["--print=cfg", "--target", &config.target]).trim().lines()
         {
@@ -507,60 +511,16 @@ impl TargetCfgs {
                 })
                 .unwrap_or_else(|| (config, None));
 
-            match name {
-                "target_arch" => {
-                    arch = Some(value.expect("target_arch should be a key-value pair").to_string());
-                }
-                "target_os" => {
-                    os = Some(value.expect("target_os sould be a key-value pair").to_string());
-                }
-                "target_env" => {
-                    env = Some(value.expect("target_env should be a key-value pair").to_string());
-                }
-                "target_abi" => {
-                    abi = Some(value.expect("target_abi should be a key-value pair").to_string());
-                }
-                "target_family" => {
-                    families
-                        .push(value.expect("target_family should be a key-value pair").to_string());
-                }
-                "target_pointer_width" => {
-                    pointer_width = Some(
-                        value
-                            .expect("target_pointer_width should be a key-value pair")
-                            .parse::<u32>()
-                            .expect("target_pointer_width should be a valid u32"),
-                    );
-                }
-                "target_endian" => {
-                    endian = Some(match value.expect("target_endian should be a key-value pair") {
-                        "big" => Endian::Big,
-                        "little" => Endian::Little,
-                        _ => panic!("target_endian should be either 'big' or 'little'"),
-                    });
-                }
-                "panic" => {
-                    panic = Some(match value.expect("panic should be a key-value pair") {
-                        "abort" => PanicStrategy::Abort,
-                        "unwind" => PanicStrategy::Unwind,
-                        _ => panic!("panic should be either 'abort' or 'unwind'"),
-                    });
-                }
-                _ => (),
+            match (name, value) {
+                // Can be overridden with `-C panic=$strategy`.
+                ("panic", Some("abort")) => cfg.panic = PanicStrategy::Abort,
+                ("panic", Some("unwind")) => cfg.panic = PanicStrategy::Unwind,
+                ("panic", other) => panic!("unexpected value for panic cfg: {other:?}"),
+                _ => {}
             }
         }
 
-        TargetCfg {
-            arch: arch.expect("target configuration should specify target_arch"),
-            os: os.expect("target configuration should specify target_os"),
-            env: env.expect("target configuration should specify target_env"),
-            abi: abi.expect("target configuration should specify target_abi"),
-            families,
-            pointer_width: pointer_width
-                .expect("target configuration should specify target_pointer_width"),
-            endian: endian.expect("target configuration should specify target_endian"),
-            panic: panic.expect("target configuration should specify panic"),
-        }
+        cfg
     }
 }
 
@@ -582,6 +542,8 @@ pub struct TargetCfg {
     endian: Endian,
     #[serde(rename = "panic-strategy", default)]
     pub(crate) panic: PanicStrategy,
+    #[serde(default)]
+    pub(crate) dynamic_linking: bool,
 }
 
 impl TargetCfg {

src/tools/compiletest/src/header/needs.rs

@@ -130,6 +130,11 @@ pub(super) fn handle_needs(
             condition: config.git_hash,
             ignore_reason: "ignored when git hashes have been omitted for building",
         },
+        Need {
+            name: "needs-dynamic-linking",
+            condition: config.target_cfg().dynamic_linking,
+            ignore_reason: "ignored on targets without dynamic linking",
+        },
     ];
 
     let (name, comment) = match ln.split_once([':', ' ']) {

src/tools/compiletest/src/runtest.rs

@@ -1810,8 +1810,8 @@ impl<'test> TestCx<'test> {
             || self.config.target.contains("wasm32")
             || self.config.target.contains("nvptx")
             || self.is_vxworks_pure_static()
-            || self.config.target.contains("sgx")
             || self.config.target.contains("bpf")
+            || !self.config.target_cfg().dynamic_linking
         {
             // We primarily compile all auxiliary libraries as dynamic libraries
             // to avoid code size bloat and large binaries as much as possible

tests/ui/issues/issue-12133-3.rs

@@ -4,7 +4,7 @@
 // aux-build:issue-12133-dylib2.rs
 // ignore-emscripten no dylib support
 // ignore-musl
-// ignore-sgx no dylib support
+// needs-dynamic-linking
 
 // pretty-expanded FIXME #23616
 

tests/ui/issues/issue-85461.rs

@@ -1,6 +1,7 @@
 // compile-flags: -Cinstrument-coverage -Ccodegen-units=4 --crate-type dylib -Copt-level=0
 // build-pass
 // needs-profiler-support
+// needs-dynamic-linking
 
 // Regression test for #85461 where MSVC sometimes fails to link instrument-coverage binaries
 // with dead code and #[inline(always)].

tests/ui/proc-macro/crt-static.rs

@@ -7,6 +7,7 @@
 // build-pass
 // force-host
 // no-prefer-dynamic
+// needs-dynamic-linking
 
 #![crate_type = "proc-macro"]