rustbuild: explicitely build some components only for a given stage

Some components are only built when they're being pulled in
as dependencies with .stage(0) specified.
They now can also be pulled in with build-all-tools, hence
only build them as stage 0.

Signed-off-by: Marc-Antoine Perennou <[email protected]>

src/bootstrap/step.rs

@@ -543,43 +543,50 @@ pub fn build_rules<'a>(build: &'a Build) -> Rules {
     rules.build("tool-rustbook", "src/tools/rustbook")
          .default(build.config.build_all_tools)
          .host(true)
+         .only_stage(0)
          .dep(|s| s.name("maybe-clean-tools"))
          .dep(|s| s.name("librustc-tool"))
          .run(move |s| compile::tool(build, s.stage, s.target, "rustbook"));
     rules.build("tool-error-index", "src/tools/error_index_generator")
          .default(build.config.build_all_tools)
          .host(true)
+         .only_stage(0)
          .dep(|s| s.name("maybe-clean-tools"))
          .dep(|s| s.name("librustc-tool"))
          .run(move |s| compile::tool(build, s.stage, s.target, "error_index_generator"));
     rules.build("tool-unstable-book-gen", "src/tools/unstable-book-gen")
          .default(build.config.build_all_tools)
          .host(true)
+         .only_stage(0)
          .dep(|s| s.name("maybe-clean-tools"))
          .dep(|s| s.name("libstd-tool"))
          .run(move |s| compile::tool(build, s.stage, s.target, "unstable-book-gen"));
     rules.build("tool-tidy", "src/tools/tidy")
          .default(build.config.build_all_tools)
          .host(true)
          .only_build(true)
+         .only_stage(0)
          .dep(|s| s.name("maybe-clean-tools"))
          .dep(|s| s.name("libstd-tool"))
          .run(move |s| compile::tool(build, s.stage, s.target, "tidy"));
     rules.build("tool-linkchecker", "src/tools/linkchecker")
          .default(build.config.build_all_tools)
          .host(true)
+         .only_stage(0)
          .dep(|s| s.name("maybe-clean-tools"))
          .dep(|s| s.name("libstd-tool"))
          .run(move |s| compile::tool(build, s.stage, s.target, "linkchecker"));
     rules.build("tool-cargotest", "src/tools/cargotest")
          .default(build.config.build_all_tools)
          .host(true)
+         .only_stage(0)
          .dep(|s| s.name("maybe-clean-tools"))
          .dep(|s| s.name("libstd-tool"))
          .run(move |s| compile::tool(build, s.stage, s.target, "cargotest"));
     rules.build("tool-compiletest", "src/tools/compiletest")
          .default(build.config.build_all_tools)
          .host(true)
+         .only_stage(0)
          .dep(|s| s.name("maybe-clean-tools"))
          .dep(|s| s.name("libtest-tool"))
          .run(move |s| compile::tool(build, s.stage, s.target, "compiletest"));
@@ -588,6 +595,7 @@ pub fn build_rules<'a>(build: &'a Build) -> Rules {
          .host(true)
          .only_build(true)
          .only_host_build(true)
+         .only_stage(0)
          .dep(|s| s.name("maybe-clean-tools"))
          .dep(|s| s.name("libstd-tool"))
          .run(move |s| compile::tool(build, s.stage, s.target, "build-manifest"));
@@ -600,12 +608,14 @@ pub fn build_rules<'a>(build: &'a Build) -> Rules {
     rules.build("tool-remote-test-client", "src/tools/remote-test-client")
          .default(build.config.build_all_tools)
          .host(true)
+         .only_stage(0)
          .dep(|s| s.name("maybe-clean-tools"))
          .dep(|s| s.name("libstd-tool"))
          .run(move |s| compile::tool(build, s.stage, s.target, "remote-test-client"));
     rules.build("tool-rust-installer", "src/tools/rust-installer")
          .default(build.config.build_all_tools)
          .host(true)
+         .only_stage(0)
          .dep(|s| s.name("maybe-clean-tools"))
          .dep(|s| s.name("libstd-tool"))
          .run(move |s| compile::tool(build, s.stage, s.target, "rust-installer"));
@@ -980,6 +990,9 @@ struct Rule<'a> {
     /// targets.
     only_build: bool,
 
+    /// Whether this rule is only built for one stage (usually stage 0).
+    only_stage: Option<u32>,
+
     /// A list of "order only" dependencies. This rules does not actually
     /// depend on these rules, but if they show up in the dependency graph then
     /// this rule must be executed after all these rules.
@@ -1008,6 +1021,7 @@ impl<'a> Rule<'a> {
             host: false,
             only_host_build: false,
             only_build: false,
+            only_stage: None,
             after: Vec::new(),
         }
     }
@@ -1059,6 +1073,11 @@ impl<'a, 'b> RuleBuilder<'a, 'b> {
         self.rule.only_host_build = only_host_build;
         self
     }
+
+    fn only_stage(&mut self, stage: u32) -> &mut Self {
+        self.rule.only_stage = Some(stage);
+        self
+    }
 }
 
 impl<'a, 'b> Drop for RuleBuilder<'a, 'b> {
@@ -1225,6 +1244,7 @@ invalid rule dependency graph detected, was a rule added and maybe typo'd?
             Subcommand::Install { ref paths } => (Kind::Install, &paths[..]),
             Subcommand::Clean => panic!(),
         };
+        let current_stage = self.sbuild.stage;
 
         let mut rules: Vec<_> = self.rules.values().filter_map(|rule| {
             if rule.kind != kind {
@@ -1278,7 +1298,10 @@ invalid rule dependency graph detected, was a rule added and maybe typo'd?
 
             hosts.iter().flat_map(move |host| {
                 arr.iter().map(move |target| {
-                    self.sbuild.name(rule.name).target(target).host(host)
+                    self.sbuild.name(rule.name)
+                               .target(target)
+                               .host(host)
+                               .stage(rule.only_stage.unwrap_or(current_stage))
                 })
             })
         }).collect()