Fix compiler for dist LLVM bitcode linker

Author: Kobzol

src/bootstrap/src/core/build_steps/compile.rs

@@ -2056,7 +2056,7 @@ impl Step for Assemble {
             if builder.config.llvm_bitcode_linker_enabled {
                 trace!("llvm-bitcode-linker enabled, installing");
                 let llvm_bitcode_linker = builder.ensure(
-                    crate::core::build_steps::tool::LlvmBitcodeLinker::for_use_by_compiler(
+                    crate::core::build_steps::tool::LlvmBitcodeLinker::from_target_compiler(
                         builder,
                         target_compiler,
                     ),

src/bootstrap/src/core/build_steps/dist.rs

@@ -1576,7 +1576,7 @@ impl Step for Extended {
             backend: "cranelift".to_string(),
         });
         add_component!("llvm-bitcode-linker" => LlvmBitcodeLinker {
-            target_compiler: compiler,
+            build_compiler: compiler,
             target
         });
 
@@ -2344,9 +2344,13 @@ impl Step for LlvmTools {
     }
 }
 
+/// Distributes the `llvm-bitcode-linker` tool so that it can be used by a compiler whose host
+/// is `target`.
 #[derive(Debug, PartialOrd, Ord, Clone, Hash, PartialEq, Eq)]
 pub struct LlvmBitcodeLinker {
-    pub target_compiler: Compiler,
+    /// The linker will be compiled by this compiler.
+    pub build_compiler: Compiler,
+    /// The linker will by usable by rustc on this host.
     pub target: TargetSelection,
 }
 
@@ -2362,7 +2366,10 @@ impl Step for LlvmBitcodeLinker {
 
     fn make_run(run: RunConfig<'_>) {
         run.builder.ensure(LlvmBitcodeLinker {
-            target_compiler: run.builder.compiler(run.builder.top_stage, run.target),
+            build_compiler: tool::LlvmBitcodeLinker::get_build_compiler_for_target(
+                run.builder,
+                run.target,
+            ),
             target: run.target,
         });
     }
@@ -2371,7 +2378,7 @@ impl Step for LlvmBitcodeLinker {
         let target = self.target;
 
         let llbc_linker = builder
-            .ensure(tool::LlvmBitcodeLinker::for_use_by_compiler(builder, self.target_compiler));
+            .ensure(tool::LlvmBitcodeLinker::from_build_compiler(self.build_compiler, target));
 
         let self_contained_bin_dir = format!("lib/rustlib/{}/bin/self-contained", target.triple);
 

src/bootstrap/src/core/build_steps/install.rs

@@ -287,7 +287,7 @@ install!((self, builder, _config),
         }
     };
     LlvmBitcodeLinker, alias = "llvm-bitcode-linker", Self::should_build(_config), only_hosts: true, {
-        if let Some(tarball) = builder.ensure(dist::LlvmBitcodeLinker { target_compiler: self.compiler, target: self.target }) {
+        if let Some(tarball) = builder.ensure(dist::LlvmBitcodeLinker { build_compiler: self.compiler, target: self.target }) {
             install_sh(builder, "llvm-bitcode-linker", self.compiler.stage, Some(self.target), &tarball);
         } else {
             builder.info(

src/bootstrap/src/core/build_steps/tool.rs

@@ -1171,8 +1171,14 @@ pub struct LlvmBitcodeLinker {
 }
 
 impl LlvmBitcodeLinker {
+    /// Returns `LlvmBitcodeLinker` that will be **compiled** by the passed compiler, for the given
+    /// `target`.
+    pub fn from_build_compiler(build_compiler: Compiler, target: TargetSelection) -> Self {
+        Self { build_compiler, target }
+    }
+
     /// Returns `LlvmBitcodeLinker` that should be **used** by the passed compiler.
-    pub fn for_use_by_compiler(builder: &Builder<'_>, target_compiler: Compiler) -> Self {
+    pub fn from_target_compiler(builder: &Builder<'_>, target_compiler: Compiler) -> Self {
         Self {
             build_compiler: get_tool_target_compiler(
                 builder,
@@ -1181,6 +1187,14 @@ impl LlvmBitcodeLinker {
             target: target_compiler.host,
         }
     }
+
+    /// Return a compiler that is able to build this tool for the given `target`.
+    pub fn get_build_compiler_for_target(
+        builder: &Builder<'_>,
+        target: TargetSelection,
+    ) -> Compiler {
+        get_tool_target_compiler(builder, ToolTargetBuildMode::Build(target))
+    }
 }
 
 impl Step for LlvmBitcodeLinker {
@@ -1196,10 +1210,7 @@ impl Step for LlvmBitcodeLinker {
 
     fn make_run(run: RunConfig<'_>) {
         run.builder.ensure(LlvmBitcodeLinker {
-            build_compiler: get_tool_target_compiler(
-                run.builder,
-                ToolTargetBuildMode::Build(run.target),
-            ),
+            build_compiler: Self::get_build_compiler_for_target(run.builder, run.target),
             target: run.target,
         });
     }

src/bootstrap/src/core/builder/tests.rs

@@ -1293,7 +1293,6 @@ mod snapshot {
         [build] rustc 0 <host> -> miri 1 <target1>
         [build] rustc 0 <host> -> cargo-miri 1 <target1>
         [build] rustc 1 <host> -> LlvmBitcodeLinker 2 <target1>
-        [build] rustc 0 <host> -> LlvmBitcodeLinker 1 <host>
         ");
     }