Improve x.py logging and defaults a bit more

src/bootstrap/bootstrap.py

@@ -189,11 +189,11 @@ def default_build_triple(verbose):
         host = next(x for x in version.split('\n') if x.startswith("host: "))
         triple = host.split("host: ")[1]
         if verbose:
-            print("detected default triple {}".format(triple))
+            print("detected default triple {} from pre-installed rustc".format(triple))
         return triple
     except Exception as e:
         if verbose:
-            print("rustup not detected: {}".format(e))
+            print("pre-installed rustc not detected: {}".format(e))
             print("falling back to auto-detect")
 
     required = sys.platform != 'win32'
@@ -726,12 +726,15 @@ def maybe_download_ci_toolchain(self):
         status = subprocess.call(["git", "diff-index", "--quiet", commit, "--", compiler, library])
         if status != 0:
             if download_rustc == "if-unchanged":
+                if self.verbose:
+                    print("warning: saw changes to compiler/ or library/ since {}; " \
+                          "ignoring `download-rustc`".format(commit))
                 return None
-            print("warning: `download-rustc` is enabled, but there are changes to \
-                   compiler/ or library/")
+            print("warning: `download-rustc` is enabled, but there are changes to " \
+                  "compiler/ or library/")
 
         if self.verbose:
-            print("using downloaded stage1 artifacts from CI (commit {})".format(commit))
+            print("using downloaded stage2 artifacts from CI (commit {})".format(commit))
         self.rustc_commit = commit
         # FIXME: support downloading artifacts from the beta channel
         self.download_toolchain(False, "nightly")

src/bootstrap/builder.rs

@@ -1578,11 +1578,11 @@ impl<'a> Builder<'a> {
                 panic!("{}", out);
             }
             if let Some(out) = self.cache.get(&step) {
-                self.verbose(&format!("{}c {:?}", "  ".repeat(stack.len()), step));
+                self.verbose_than(1, &format!("{}c {:?}", "  ".repeat(stack.len()), step));
 
                 return out;
             }
-            self.verbose(&format!("{}> {:?}", "  ".repeat(stack.len()), step));
+            self.verbose_than(1, &format!("{}> {:?}", "  ".repeat(stack.len()), step));
             stack.push(Box::new(step.clone()));
         }
 
@@ -1605,7 +1605,7 @@ impl<'a> Builder<'a> {
             let cur_step = stack.pop().expect("step stack empty");
             assert_eq!(cur_step.downcast_ref(), Some(&step));
         }
-        self.verbose(&format!("{}< {:?}", "  ".repeat(self.stack.borrow().len()), step));
+        self.verbose_than(1, &format!("{}< {:?}", "  ".repeat(self.stack.borrow().len()), step));
         self.cache.put(step, out.clone());
         out
     }

src/bootstrap/defaults/config.tools.toml

@@ -11,6 +11,10 @@ incremental = true
 # This cuts compile times by almost 60x, but means you can't modify the compiler.
 download-rustc = "if-unchanged"
 
+[build]
+# Document with the in-tree rustdoc by default, since `download-rustc` makes it quick to compile.
+doc-stage = 2
+
 [llvm]
 # Will download LLVM from CI if available on your platform.
 download-ci-llvm = "if-available"