Auto merge of #76799 - Mark-Simulacrum:fix-cross-compile-dist, r=alexcrichton

Fix cross compiling dist/build invocations

I am uncertain why the first commit is not affecting CI. I suspect it's because we pass --disable-docs on most of our cross-compilation builders. The second commit doesn't affect CI because CI runs x.py dist, not x.py build.

Both commits are standalone; together they should resolve #76733. The first commit doesn't really fix that issue but rather just fixes cross-compiled x.py dist, resolving a bug introduced in #76549.

3 files changed, 56 insertions, 2 deletions

diff --git a/src/bootstrap/builder/tests.rs b/src/bootstrap/builder/tests.rs
index cd90021507e..4a9082d3e85 100644
--- a/src/bootstrap/builder/tests.rs
+++ b/src/bootstrap/builder/tests.rs
@@ -94,6 +94,54 @@ mod defaults {
     }
 
     #[test]
+    fn build_cross_compile() {
+        let config = Config { stage: 1, ..configure("build", &["B"], &["B"]) };
+        let build = Build::new(config);
+        let mut builder = Builder::new(&build);
+        builder.run_step_descriptions(&Builder::get_step_descriptions(Kind::Build), &[]);
+
+        let a = TargetSelection::from_user("A");
+        let b = TargetSelection::from_user("B");
+
+        // Ideally, this build wouldn't actually have `target: a`
+        // rustdoc/rustcc/std here (the user only requested a host=B build, so
+        // there's not really a need for us to build for target A in this case
+        // (since we're producing stage 1 libraries/binaries).  But currently
+        // rustbuild is just a bit buggy here; this should be fixed though.
+        assert_eq!(
+            first(builder.cache.all::<compile::Std>()),
+            &[
+                compile::Std { compiler: Compiler { host: a, stage: 0 }, target: a },
+                compile::Std { compiler: Compiler { host: a, stage: 1 }, target: a },
+                compile::Std { compiler: Compiler { host: a, stage: 0 }, target: b },
+                compile::Std { compiler: Compiler { host: a, stage: 1 }, target: b },
+            ]
+        );
+        assert_eq!(
+            first(builder.cache.all::<compile::Assemble>()),
+            &[
+                compile::Assemble { target_compiler: Compiler { host: a, stage: 0 } },
+                compile::Assemble { target_compiler: Compiler { host: a, stage: 1 } },
+                compile::Assemble { target_compiler: Compiler { host: b, stage: 1 } },
+            ]
+        );
+        assert_eq!(
+            first(builder.cache.all::<tool::Rustdoc>()),
+            &[
+                tool::Rustdoc { compiler: Compiler { host: a, stage: 1 } },
+                tool::Rustdoc { compiler: Compiler { host: b, stage: 1 } },
+            ],
+        );
+        assert_eq!(
+            first(builder.cache.all::<compile::Rustc>()),
+            &[
+                compile::Rustc { compiler: Compiler { host: a, stage: 0 }, target: a },
+                compile::Rustc { compiler: Compiler { host: a, stage: 0 }, target: b },
+            ]
+        );
+    }
+
+    #[test]
     fn doc_default() {
         let mut config = configure("doc", &[], &[]);
         config.compiler_docs = true;
diff --git a/src/bootstrap/doc.rs b/src/bootstrap/doc.rs
index 97f32b61fb9..aa670bd9a2e 100644
--- a/src/bootstrap/doc.rs
+++ b/src/bootstrap/doc.rs
@@ -752,6 +752,7 @@ impl Step for RustcBook {
         let out_listing = out_base.join("src/lints");
         builder.cp_r(&builder.src.join("src/doc/rustc"), &out_base);
         builder.info(&format!("Generating lint docs ({})", self.target));
+
         let rustc = builder.rustc(self.compiler);
         // The tool runs `rustc` for extracting output examples, so it needs a
         // functional sysroot.
@@ -762,7 +763,8 @@ impl Step for RustcBook {
         cmd.arg("--out");
         cmd.arg(&out_listing);
         cmd.arg("--rustc");
-        cmd.arg(rustc);
+        cmd.arg(&rustc);
+        cmd.arg("--rustc-target").arg(&self.target.rustc_target_arg());
         if builder.config.verbose() {
             cmd.arg("--verbose");
         }
diff --git a/src/bootstrap/tool.rs b/src/bootstrap/tool.rs
index 460dffb5c8a..290e3744852 100644
--- a/src/bootstrap/tool.rs
+++ b/src/bootstrap/tool.rs
@@ -470,7 +470,11 @@ impl Step for Rustdoc {
 
     fn make_run(run: RunConfig<'_>) {
         run.builder.ensure(Rustdoc {
-            compiler: run.builder.compiler(run.builder.top_stage, run.build_triple()),
+            // Note: this is somewhat unique in that we actually want a *target*
+            // compiler here, because rustdoc *is* a compiler. We won't be using
+            // this as the compiler to build with, but rather this is "what
+            // compiler are we producing"?
+            compiler: run.builder.compiler(run.builder.top_stage, run.target),
         });
     }