Add compiler_for_std

Author: Kobzol

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

@@ -150,7 +150,7 @@ impl Step for Std {
         trace!(force_recompile);
 
         run.builder.ensure(Std {
-            build_compiler: run.builder.compiler(run.builder.top_stage, run.build_triple()),
+            build_compiler: run.builder.compiler_for_std(run.builder.top_stage, run.target),
             target: run.target,
             crates,
             force_recompile,

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

@@ -115,7 +115,7 @@ impl Step for JsonDocs {
 
     fn make_run(run: RunConfig<'_>) {
         run.builder.ensure(JsonDocs {
-            build_compiler: run.builder.compiler(run.builder.top_stage, run.builder.host_target),
+            build_compiler: run.builder.compiler_for_std(run.builder.top_stage, run.target),
             target: run.target,
         });
     }

src/bootstrap/src/core/build_steps/doc.rs

@@ -616,7 +616,9 @@ impl Step for Std {
             return;
         }
         run.builder.ensure(Std {
-            build_compiler: run.builder.compiler(run.builder.top_stage, run.builder.host_target),
+            build_compiler: run
+                .builder
+                .compiler_for_std(run.builder.top_stage, run.builder.host_target),
             target: run.target,
             format: if run.builder.config.cmd.json() {
                 DocumentationFormat::Json

src/bootstrap/src/core/builder/mod.rs

@@ -1360,6 +1360,14 @@ impl<'a> Builder<'a> {
         self.ensure(compile::Assemble { target_compiler: Compiler::new(stage, host) })
     }
 
+    pub fn compiler_for_std(&self, stage: u32, target: TargetSelection) -> Compiler {
+        if compile::Std::should_be_uplifted_from_stage_1(self, stage, target) {
+            self.compiler(1, self.host_target)
+        } else {
+            self.compiler(stage, self.host_target)
+        }
+    }
+
     /// Similar to `compiler`, except handles the full-bootstrap option to
     /// silently use the stage1 compiler instead of a stage2 compiler if one is
     /// requested.