auto merge of #15024 : kmcallister/rust/lint, r=alexcrichton

This is a rebase of #14804 with two new commits on top to implement and test lint plugins.

r? @alexcrichton @huonw: Can you take a look at the new commits, and also weigh in about any issues from the old PR that you feel are still unresolved? I'm leaving the old branch alone to preserve discussion history.

Author: bors

src/librustc/driver/config.rs

@@ -19,7 +19,7 @@ use back;
 use back::link;
 use back::target_strs;
 use back::{arm, x86, x86_64, mips, mipsel};
-use middle::lint;
+use lint;
 
 use syntax::abi;
 use syntax::ast;
@@ -70,7 +70,8 @@ pub struct Options {
     pub gc: bool,
     pub optimize: OptLevel,
     pub debuginfo: DebugInfoLevel,
-    pub lint_opts: Vec<(lint::Lint, lint::Level)> ,
+    pub lint_opts: Vec<(String, lint::Level)>,
+    pub describe_lints: bool,
     pub output_types: Vec<back::link::OutputType> ,
     // This was mutable for rustpkg, which updates search paths based on the
     // parsed code. It remains mutable in case its replacements wants to use
@@ -104,6 +105,7 @@ pub fn basic_options() -> Options {
         optimize: No,
         debuginfo: NoDebugInfo,
         lint_opts: Vec::new(),
+        describe_lints: false,
         output_types: Vec::new(),
         addl_lib_search_paths: RefCell::new(HashSet::new()),
         maybe_sysroot: None,
@@ -585,30 +587,15 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
     let no_trans = matches.opt_present("no-trans");
     let no_analysis = matches.opt_present("no-analysis");
 
-    let lint_levels = [lint::Allow, lint::Warn,
-                       lint::Deny, lint::Forbid];
-    let mut lint_opts = Vec::new();
-    let lint_dict = lint::get_lint_dict();
-    for level in lint_levels.iter() {
-        let level_name = lint::level_to_str(*level);
-
-        let level_short = level_name.slice_chars(0, 1);
-        let level_short = level_short.to_ascii().to_upper().into_str();
-        let flags = matches.opt_strs(level_short.as_slice())
-                           .move_iter()
-                           .collect::<Vec<_>>()
-                           .append(matches.opt_strs(level_name).as_slice());
-        for lint_name in flags.iter() {
-            let lint_name = lint_name.replace("-", "_").into_string();
-            match lint_dict.find_equiv(&lint_name) {
-              None => {
-                early_error(format!("unknown {} flag: {}",
-                                    level_name,
-                                    lint_name).as_slice());
-              }
-              Some(lint) => {
-                lint_opts.push((lint.lint, *level));
-              }
+    let mut lint_opts = vec!();
+    let mut describe_lints = false;
+
+    for &level in [lint::Allow, lint::Warn, lint::Deny, lint::Forbid].iter() {
+        for lint_name in matches.opt_strs(level.as_str()).move_iter() {
+            if lint_name.as_slice() == "help" {
+                describe_lints = true;
+            } else {
+                lint_opts.push((lint_name.replace("-", "_").into_string(), level));
             }
         }
     }
@@ -752,6 +739,7 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
         optimize: opt_level,
         debuginfo: debuginfo,
         lint_opts: lint_opts,
+        describe_lints: describe_lints,
         output_types: output_types,
         addl_lib_search_paths: RefCell::new(addl_lib_search_paths),
         maybe_sysroot: sysroot_opt,

src/librustc/driver/driver.rs

@@ -20,12 +20,13 @@ use metadata::common::LinkMeta;
 use metadata::creader;
 use middle::cfg;
 use middle::cfg::graphviz::LabelledCFG;
-use middle::{trans, freevars, stability, kind, ty, typeck, lint, reachable};
+use middle::{trans, freevars, stability, kind, ty, typeck, reachable};
 use middle::dependency_format;
 use middle;
 use plugin::load::Plugins;
 use plugin::registry::Registry;
 use plugin;
+use lint;
 use util::common::time;
 use util::ppaux;
 use util::nodemap::{NodeSet};
@@ -78,8 +79,12 @@ pub fn compile_input(sess: Session,
                                                  &sess);
             let id = link::find_crate_id(krate.attrs.as_slice(),
                                          outputs.out_filestem.as_slice());
-            let (expanded_crate, ast_map) =
-                phase_2_configure_and_expand(&sess, krate, &id);
+            let (expanded_crate, ast_map)
+                = match phase_2_configure_and_expand(&sess, krate, &id) {
+                    None => return,
+                    Some(p) => p,
+                };
+
             (outputs, expanded_crate, ast_map)
         };
         write_out_deps(&sess, input, &outputs, &expanded_crate);
@@ -172,10 +177,12 @@ pub fn phase_1_parse_input(sess: &Session, cfg: ast::CrateConfig, input: &Input)
 /// syntax expansion, secondary `cfg` expansion, synthesis of a test
 /// harness if one is to be provided and injection of a dependency on the
 /// standard library and prelude.
+///
+/// Returns `None` if we're aborting after handling -W help.
 pub fn phase_2_configure_and_expand(sess: &Session,
                                     mut krate: ast::Crate,
                                     crate_id: &CrateId)
-                                    -> (ast::Crate, syntax::ast_map::Map) {
+                                    -> Option<(ast::Crate, syntax::ast_map::Map)> {
     let time_passes = sess.time_passes();
 
     *sess.crate_types.borrow_mut() = collect_crate_types(sess, krate.attrs.as_slice());
@@ -209,7 +216,24 @@ pub fn phase_2_configure_and_expand(sess: &Session,
         }
     });
 
-    let Registry { syntax_exts, .. } = registry;
+    let Registry { syntax_exts, lint_passes, .. } = registry;
+
+    {
+        let mut ls = sess.lint_store.borrow_mut();
+        for pass in lint_passes.move_iter() {
+            ls.register_pass(Some(sess), true, pass);
+        }
+    }
+
+    // Lint plugins are registered; now we can process command line flags.
+    if sess.opts.describe_lints {
+        super::describe_lints(&*sess.lint_store.borrow(), true);
+        return None;
+    }
+    sess.lint_store.borrow_mut().process_command_line(sess);
+
+    // Abort if there are errors from lint processing or a plugin registrar.
+    sess.abort_if_errors();
 
     krate = time(time_passes, "expansion", (krate, macros, syntax_exts),
         |(krate, macros, syntax_exts)| {
@@ -253,7 +277,7 @@ pub fn phase_2_configure_and_expand(sess: &Session,
         krate.encode(&mut json).unwrap();
     }
 
-    (krate, map)
+    Some((krate, map))
 }
 
 pub struct CrateAnalysis {
@@ -366,7 +390,7 @@ pub fn phase_3_run_analysis_passes(sess: Session,
     });
 
     time(time_passes, "lint checking", (), |_|
-         lint::check_crate(&ty_cx, &exported_items, krate));
+         lint::check_crate(&ty_cx, krate, &exported_items));
 
     CrateAnalysis {
         exp_map2: exp_map2,
@@ -630,9 +654,11 @@ pub fn pretty_print_input(sess: Session,
 
     let (krate, ast_map, is_expanded) = match ppm {
         PpmExpanded | PpmExpandedIdentified | PpmTyped | PpmFlowGraph(_) => {
-            let (krate, ast_map) = phase_2_configure_and_expand(&sess,
-                                                                krate,
-                                                                &id);
+            let (krate, ast_map)
+                = match phase_2_configure_and_expand(&sess, krate, &id) {
+                    None => return,
+                    Some(p) => p,
+                };
             (krate, Some(ast_map), true)
         }
         _ => (krate, None, false)
@@ -766,15 +792,15 @@ pub fn collect_crate_types(session: &Session,
                 }
                 Some(ref n) if n.equiv(&("bin")) => Some(config::CrateTypeExecutable),
                 Some(_) => {
-                    session.add_lint(lint::UnknownCrateType,
+                    session.add_lint(lint::builtin::UNKNOWN_CRATE_TYPE,
                                      ast::CRATE_NODE_ID,
                                      a.span,
                                      "invalid `crate_type` \
                                       value".to_string());
                     None
                 }
                 _ => {
-                    session.add_lint(lint::UnknownCrateType,
+                    session.add_lint(lint::builtin::UNKNOWN_CRATE_TYPE,
                                      ast::CRATE_NODE_ID,
                                      a.span,
                                      "`crate_type` requires a \

src/librustc/driver/mod.rs

@@ -13,11 +13,11 @@ pub use syntax::diagnostic;
 use back::link;
 use driver::driver::{Input, FileInput, StrInput};
 use driver::session::{Session, build_session};
-use middle::lint;
+use lint::Lint;
+use lint;
 use metadata;
 
 use std::any::AnyRefExt;
-use std::cmp;
 use std::io;
 use std::os;
 use std::str;
@@ -49,9 +49,18 @@ fn run_compiler(args: &[String]) {
         Some(matches) => matches,
         None => return
     };
+    let sopts = config::build_session_options(&matches);
 
     let (input, input_file_path) = match matches.free.len() {
-        0u => early_error("no input filename given"),
+        0u => {
+            if sopts.describe_lints {
+                let mut ls = lint::LintStore::new();
+                ls.register_builtin(None);
+                describe_lints(&ls, false);
+                return;
+            }
+            early_error("no input filename given");
+        }
         1u => {
             let ifile = matches.free.get(0).as_slice();
             if ifile == "-" {
@@ -66,7 +75,6 @@ fn run_compiler(args: &[String]) {
         _ => early_error("multiple input filenames provided")
     };
 
-    let sopts = config::build_session_options(&matches);
     let sess = build_session(sopts, input_file_path);
     let cfg = config::build_configuration(&sess);
     let odir = matches.opt_str("out-dir").map(|o| Path::new(o));
@@ -124,41 +132,68 @@ Additional help:
                              config::optgroups().as_slice()));
 }
 
-fn describe_warnings() {
+fn describe_lints(lint_store: &lint::LintStore, loaded_plugins: bool) {
     println!("
 Available lint options:
     -W <foo>           Warn about <foo>
     -A <foo>           Allow <foo>
     -D <foo>           Deny <foo>
     -F <foo>           Forbid <foo> (deny, and deny all overrides)
-");
 
-    let lint_dict = lint::get_lint_dict();
-    let mut lint_dict = lint_dict.move_iter()
-                                 .map(|(k, v)| (v, k))
-                                 .collect::<Vec<(lint::LintSpec, &'static str)> >();
-    lint_dict.as_mut_slice().sort();
+");
 
-    let mut max_key = 0;
-    for &(_, name) in lint_dict.iter() {
-        max_key = cmp::max(name.len(), max_key);
-    }
-    fn padded(max: uint, s: &str) -> String {
-        format!("{}{}", " ".repeat(max - s.len()), s)
+    fn sort_lints(lints: Vec<(&'static Lint, bool)>) -> Vec<&'static Lint> {
+        let mut lints: Vec<_> = lints.move_iter().map(|(x, _)| x).collect();
+        lints.sort_by(|x: &&Lint, y: &&Lint| {
+            match x.default_level.cmp(&y.default_level) {
+                // The sort doesn't case-fold but it's doubtful we care.
+                Equal => x.name.cmp(&y.name),
+                r => r,
+            }
+        });
+        lints
     }
-    println!("\nAvailable lint checks:\n");
-    println!("    {}  {:7.7s}  {}",
-             padded(max_key, "name"), "default", "meaning");
-    println!("    {}  {:7.7s}  {}\n",
-             padded(max_key, "----"), "-------", "-------");
-    for (spec, name) in lint_dict.move_iter() {
-        let name = name.replace("_", "-");
-        println!("    {}  {:7.7s}  {}",
-                 padded(max_key, name.as_slice()),
-                 lint::level_to_str(spec.default),
-                 spec.desc);
+
+    let (plugin, builtin) = lint_store.get_lints().partitioned(|&(_, p)| p);
+    let plugin = sort_lints(plugin);
+    let builtin = sort_lints(builtin);
+
+    // FIXME (#7043): We should use the width in character cells rather than
+    // the number of codepoints.
+    let max_name_len = plugin.iter().chain(builtin.iter())
+        .map(|&s| s.name.char_len())
+        .max().unwrap_or(0);
+    let padded = |x: &str| {
+        " ".repeat(max_name_len - x.char_len()).append(x)
+    };
+
+    println!("Lint checks provided by rustc:\n");
+    println!("    {}  {:7.7s}  {}", padded("name"), "default", "meaning");
+    println!("    {}  {:7.7s}  {}", padded("----"), "-------", "-------");
+
+    let print_lints = |lints: Vec<&Lint>| {
+        for lint in lints.move_iter() {
+            let name = lint.name_lower().replace("_", "-");
+            println!("    {}  {:7.7s}  {}",
+                     padded(name.as_slice()), lint.default_level.as_str(), lint.desc);
+        }
+        println!("\n");
+    };
+
+    print_lints(builtin);
+
+    match (loaded_plugins, plugin.len()) {
+        (false, 0) => {
+            println!("Compiler plugins can provide additional lints. To see a listing of these, \
+                      re-run `rustc -W help` with a crate filename.");
+        }
+        (false, _) => fail!("didn't load lint plugins but got them anyway!"),
+        (true, 0) => println!("This crate does not load any lint plugins."),
+        (true, _) => {
+            println!("Lint checks provided by plugins loaded by this crate:\n");
+            print_lints(plugin);
+        }
     }
-    println!("");
 }
 
 fn describe_debug_flags() {
@@ -214,12 +249,7 @@ pub fn handle_options(mut args: Vec<String>) -> Option<getopts::Matches> {
         return None;
     }
 
-    let lint_flags = matches.opt_strs("W").move_iter().collect::<Vec<_>>().append(
-                                    matches.opt_strs("warn").as_slice());
-    if lint_flags.iter().any(|x| x.as_slice() == "help") {
-        describe_warnings();
-        return None;
-    }
+    // Don't handle -W help here, because we might first load plugins.
 
     let r = matches.opt_strs("Z");
     if r.iter().any(|x| x.as_slice() == "help") {