Support extra-verbose builds:

- The bootstrap crate currently passes -v to Cargo if itself invoked
with -vv.  But Cargo supports -vv (to show build script output), so make
bootstrap pass that if itself invoked with -vvv.  (More specifically,
pass N '-v's to Cargo if invoked with N+1 of them.)

- bootstrap.py currently tries to pass on up to two '-v's to cargo when
building bootstrap, but incorrectly ('-v' is marked as 'store_true', so
argparse stores either False or True, ignoring multiple '-v's).  Fix
this, allow passing any number of '-v's, and make it consistent with
bootstrap's invocation of Cargo (i.e. subtract one from the number of
'-v's).

- Also improve bootstrap.py's config.toml 'parsing' to support arbitrary
verbosity levels, + allow command line to override it.

src/bootstrap/bootstrap.py

@@ -597,10 +597,8 @@ def build_bootstrap(self):
                 self.cargo()))
         args = [self.cargo(), "build", "--manifest-path",
                 os.path.join(self.rust_root, "src/bootstrap/Cargo.toml")]
-        if self.verbose:
+        for _ in range(1, self.verbose):
             args.append("--verbose")
-            if self.verbose > 1:
-                args.append("--verbose")
         if self.use_locked_deps:
             args.append("--locked")
         if self.use_vendored_sources:
@@ -675,7 +673,7 @@ def bootstrap(help_triggered):
     parser.add_argument('--config')
     parser.add_argument('--build')
     parser.add_argument('--clean', action='store_true')
-    parser.add_argument('-v', '--verbose', action='store_true')
+    parser.add_argument('-v', '--verbose', action='count', default=0)
 
     args = [a for a in sys.argv if a != '-h' and a != '--help']
     args, _ = parser.parse_known_args(args)
@@ -691,10 +689,9 @@ def bootstrap(help_triggered):
     except (OSError, IOError):
         pass
 
-    if '\nverbose = 2' in build.config_toml:
-        build.verbose = 2
-    elif '\nverbose = 1' in build.config_toml:
-        build.verbose = 1
+    match = re.search(r'\nverbose = (\d+)', build.config_toml)
+    if match is not None:
+        build.verbose = max(build.verbose, int(match.group(1)))
 
     build.use_vendored_sources = '\nvendor = true' in build.config_toml
 

src/bootstrap/builder.rs

@@ -763,7 +763,7 @@ impl<'a> Builder<'a> {
             cargo.env("WINAPI_NO_BUNDLED_LIBRARIES", "1");
         }
 
-        if self.is_very_verbose() {
+        for _ in 1..self.verbosity {
             cargo.arg("-v");
         }
 

src/bootstrap/flags.rs

@@ -29,7 +29,7 @@ use cache::{Interned, INTERNER};
 
 /// Deserialized version of all flags for this compile.
 pub struct Flags {
-    pub verbose: usize, // verbosity level: 0 == not verbose, 1 == verbose, 2 == very verbose
+    pub verbose: usize, // number of -v args; each extra -v after the first is passed to Cargo
     pub on_fail: Option<String>,
     pub stage: Option<u32>,
     pub keep_stage: Option<u32>,

src/bootstrap/lib.rs

@@ -605,10 +605,6 @@ impl Build {
         self.verbosity > 0
     }
 
-    pub fn is_very_verbose(&self) -> bool {
-        self.verbosity > 1
-    }
-
     /// Prints a message if this build is configured in verbose mode.
     fn verbose(&self, msg: &str) {
         if self.is_verbose() {