auto merge of #20032 : Manishearth/rust/plugin-loader, r=cmr

`rustc something.rs -L folder_with_plugin_dylib/ -Z extra-plugins=foo` works via this

My way of testing this is by cloning https://github.com/Manishearth/rust-clippy, `cargo build`ing it, and then running `rustc examples/box_vec.rs -L target/ -Z extra-plugins=rust_clippy` after editing out the `exern crate rust_clippy` from `box_vec.rs`

r? @huonw

fixes #15446

Author: bors

src/compiletest/header.rs

@@ -42,6 +42,8 @@ pub struct TestProps {
     pub pretty_compare_only: bool,
     // Patterns which must not appear in the output of a cfail test.
     pub forbid_output: Vec<String>,
+    // Ignore errors which originate from a command line span
+    pub ignore_command_line: bool,
 }
 
 // Load any test directives embedded in the file
@@ -60,6 +62,8 @@ pub fn load_props(testfile: &Path) -> TestProps {
     let mut pretty_mode = None;
     let mut pretty_compare_only = false;
     let mut forbid_output = Vec::new();
+    let mut ignore_command_line = false;
+
     iter_header(testfile, |ln| {
         match parse_error_pattern(ln) {
           Some(ep) => error_patterns.push(ep),
@@ -102,6 +106,10 @@ pub fn load_props(testfile: &Path) -> TestProps {
             pretty_compare_only = parse_pretty_compare_only(ln);
         }
 
+        if !ignore_command_line {
+            ignore_command_line = parse_ignore_command_line(ln);
+        }
+
         match parse_aux_build(ln) {
             Some(ab) => { aux_builds.push(ab); }
             None => {}
@@ -140,6 +148,7 @@ pub fn load_props(testfile: &Path) -> TestProps {
         pretty_mode: pretty_mode.unwrap_or("normal".to_string()),
         pretty_compare_only: pretty_compare_only,
         forbid_output: forbid_output,
+        ignore_command_line: ignore_command_line,
     }
 }
 
@@ -291,6 +300,10 @@ fn parse_pretty_compare_only(line: &str) -> bool {
     parse_name_directive(line, "pretty-compare-only")
 }
 
+fn parse_ignore_command_line(line: &str) -> bool {
+    parse_name_directive(line, "ignore-command-line")
+}
+
 fn parse_exec_env(line: &str) -> Option<(String, String)> {
     parse_name_value_directive(line, "exec-env").map(|nv| {
         // nv is either FOO or FOO=BAR

src/compiletest/runtest.rs

@@ -104,7 +104,7 @@ fn run_cfail_test(config: &Config, props: &TestProps, testfile: &Path) {
         if !props.error_patterns.is_empty() {
             fatal("both error pattern and expected errors specified");
         }
-        check_expected_errors(expected_errors, testfile, &proc_res);
+        check_expected_errors(props, expected_errors, testfile, &proc_res);
     } else {
         check_error_patterns(props, testfile, output_to_check.as_slice(), &proc_res);
     }
@@ -941,7 +941,8 @@ fn check_forbid_output(props: &TestProps,
     }
 }
 
-fn check_expected_errors(expected_errors: Vec<errors::ExpectedError> ,
+fn check_expected_errors(props: &TestProps,
+                         expected_errors: Vec<errors::ExpectedError> ,
                          testfile: &Path,
                          proc_res: &ProcRes) {
 
@@ -996,6 +997,11 @@ fn check_expected_errors(expected_errors: Vec<errors::ExpectedError> ,
             was_expected = true;
         }
 
+        if line.starts_with("<command line option>") &&
+           props.ignore_command_line {
+            was_expected = true;
+        }
+
         if !was_expected && is_compiler_error_or_warning(line) {
             fatal_proc_rec(format!("unexpected compiler error or warning: '{}'",
                                   line).as_slice(),

src/librustc/metadata/creader.rs

@@ -26,7 +26,7 @@ use syntax::ast;
 use syntax::abi;
 use syntax::attr;
 use syntax::attr::AttrMetaMethods;
-use syntax::codemap::{Span, mk_sp};
+use syntax::codemap::{COMMAND_LINE_SP, Span, mk_sp};
 use syntax::parse;
 use syntax::parse::token::InternedString;
 use syntax::parse::token;
@@ -445,8 +445,20 @@ impl<'a> CrateReader<'a> {
     }
 
     pub fn read_plugin_metadata<'b>(&'b mut self,
-                                    vi: &'b ast::ViewItem) -> PluginMetadata<'b> {
-        let info = self.extract_crate_info(vi).unwrap();
+                                    krate: CrateOrString<'b>) -> PluginMetadata<'b> {
+        let (info, span) = match krate {
+            CrateOrString::Krate(c) => {
+                (self.extract_crate_info(c).unwrap(), c.span)
+            }
+            CrateOrString::Str(s) => {
+                (CrateInfo {
+                     name: s.to_string(),
+                     ident: s.to_string(),
+                     id: ast::DUMMY_NODE_ID,
+                     should_link: true,
+                 }, COMMAND_LINE_SP)
+            }
+        };
         let target_triple = &self.sess.opts.target_triple[];
         let is_cross = target_triple != config::host_triple();
         let mut should_link = info.should_link && !is_cross;
@@ -455,7 +467,7 @@ impl<'a> CrateReader<'a> {
         let name = info.name.clone();
         let mut load_ctxt = loader::Context {
             sess: self.sess,
-            span: vi.span,
+            span: span,
             ident: &ident[],
             crate_name: &name[],
             hash: None,
@@ -486,7 +498,7 @@ impl<'a> CrateReader<'a> {
         let metadata = if register {
             // Register crate now to avoid double-reading metadata
             let (_, cmd, _) = self.register_crate(&None, &info.ident[],
-                                &info.name[], vi.span, library);
+                                &info.name[], span, library);
             PMDSource::Registered(cmd)
         } else {
             // Not registering the crate; just hold on to the metadata
@@ -498,12 +510,18 @@ impl<'a> CrateReader<'a> {
             metadata: metadata,
             dylib: dylib,
             info: info,
-            vi_span: vi.span,
+            vi_span: span,
             target_only: target_only,
         }
     }
 }
 
+#[derive(Copy)]
+pub enum CrateOrString<'a> {
+    Krate(&'a ast::ViewItem),
+    Str(&'a str)
+}
+
 impl<'a> PluginMetadata<'a> {
     /// Read exported macros
     pub fn exported_macros(&self) -> Vec<ast::MacroDef> {

src/librustc/middle/infer/region_inference/graphviz.rs

@@ -22,7 +22,6 @@ use middle::ty;
 use super::Constraint;
 use middle::infer::SubregionOrigin;
 use middle::infer::region_inference::RegionVarBindings;
-use session::config;
 use util::nodemap::{FnvHashMap, FnvHashSet};
 use util::ppaux::Repr;
 
@@ -55,7 +54,7 @@ pub fn maybe_print_constraints_for<'a, 'tcx>(region_vars: &RegionVarBindings<'a,
                                              subject_node: ast::NodeId) {
     let tcx = region_vars.tcx;
 
-    if !region_vars.tcx.sess.debugging_opt(config::PRINT_REGION_GRAPH) {
+    if !region_vars.tcx.sess.opts.debugging_opts.print_region_graph {
         return;
     }
 

src/librustc/plugin/load.rs

@@ -11,7 +11,7 @@
 //! Used by `rustc` when loading a plugin, or a crate with exported macros.
 
 use session::Session;
-use metadata::creader::CrateReader;
+use metadata::creader::{CrateOrString, CrateReader};
 use plugin::registry::Registry;
 
 use std::mem;
@@ -44,11 +44,11 @@ pub struct Plugins {
     pub registrars: Vec<PluginRegistrar>,
 }
 
-struct PluginLoader<'a> {
+pub struct PluginLoader<'a> {
     sess: &'a Session,
     span_whitelist: HashSet<Span>,
     reader: CrateReader<'a>,
-    plugins: Plugins,
+    pub plugins: Plugins,
 }
 
 impl<'a> PluginLoader<'a> {
@@ -67,7 +67,7 @@ impl<'a> PluginLoader<'a> {
 
 /// Read plugin metadata and dynamically load registrar functions.
 pub fn load_plugins(sess: &Session, krate: &ast::Crate,
-                    addl_plugins: Option<Plugins>) -> Plugins {
+                    addl_plugins: Option<Vec<String>>) -> Plugins {
     let mut loader = PluginLoader::new(sess);
 
     // We need to error on `#[macro_use] extern crate` when it isn't at the
@@ -79,19 +79,14 @@ pub fn load_plugins(sess: &Session, krate: &ast::Crate,
 
     visit::walk_crate(&mut loader, krate);
 
-    let mut plugins = loader.plugins;
-
-    match addl_plugins {
-        Some(addl_plugins) => {
-            // Add in the additional plugins requested by the frontend
-            let Plugins { macros: addl_macros, registrars: addl_registrars } = addl_plugins;
-            plugins.macros.extend(addl_macros.into_iter());
-            plugins.registrars.extend(addl_registrars.into_iter());
+    if let Some(plugins) = addl_plugins {
+        for plugin in plugins.iter() {
+            loader.load_plugin(CrateOrString::Str(plugin.as_slice()),
+                                                  None, None, None)
         }
-        None => ()
     }
 
-    return plugins;
+    return loader.plugins;
 }
 
 // note that macros aren't expanded yet, and therefore macros can't add plugins.
@@ -160,22 +155,39 @@ impl<'a, 'v> Visitor<'v> for PluginLoader<'a> {
             }
         }
 
+        self.load_plugin(CrateOrString::Krate(vi), plugin_attr, macro_selection, Some(reexport))
+    }
+
+    fn visit_mac(&mut self, _: &ast::Mac) {
+        // bummer... can't see plugins inside macros.
+        // do nothing.
+    }
+}
+
+impl<'a> PluginLoader<'a> {
+    pub fn load_plugin<'b>(&mut self,
+                           c: CrateOrString<'b>,
+                           plugin_attr: Option<P<ast::MetaItem>>,
+                           macro_selection: Option<HashSet<token::InternedString>>,
+                           reexport: Option<HashSet<token::InternedString>>) {
         let mut macros = vec![];
         let mut registrar = None;
 
-        let load_macros = match macro_selection.as_ref() {
-            Some(sel) => sel.len() != 0 || reexport.len() != 0,
-            None => true,
+        let load_macros = match (macro_selection.as_ref(), reexport.as_ref()) {
+            (Some(sel), Some(re)) => sel.len() != 0 || re.len() != 0,
+            _ => true,
         };
         let load_registrar = plugin_attr.is_some();
 
-        if load_macros && !self.span_whitelist.contains(&vi.span) {
-            self.sess.span_err(vi.span, "an `extern crate` loading macros must be at \
-                                         the crate root");
-        }
+        if let CrateOrString::Krate(vi) = c {
+            if load_macros && !self.span_whitelist.contains(&vi.span) {
+                self.sess.span_err(vi.span, "an `extern crate` loading macros must be at \
+                                             the crate root");
+            }
+       }
 
         if load_macros || load_registrar {
-            let pmd = self.reader.read_plugin_metadata(vi);
+            let pmd = self.reader.read_plugin_metadata(c);
             if load_macros {
                 macros = pmd.exported_macros();
             }
@@ -190,29 +202,26 @@ impl<'a, 'v> Visitor<'v> for PluginLoader<'a> {
                 None => true,
                 Some(sel) => sel.contains(&name),
             };
-            def.export = reexport.contains(&name);
+            def.export = if let Some(ref re) = reexport {
+                re.contains(&name)
+            } else {
+                false // Don't reexport macros from crates loaded from the command line
+            };
             self.plugins.macros.push(def);
         }
 
         if let Some((lib, symbol)) = registrar {
-            let fun = self.dylink_registrar(vi, lib, symbol);
+            let fun = self.dylink_registrar(c, lib, symbol);
             self.plugins.registrars.push(PluginRegistrar {
                 fun: fun,
                 args: plugin_attr.unwrap(),
             });
         }
     }
 
-    fn visit_mac(&mut self, _: &ast::Mac) {
-        // bummer... can't see plugins inside macros.
-        // do nothing.
-    }
-}
-
-impl<'a> PluginLoader<'a> {
     // Dynamically link a registrar function into the compiler process.
-    fn dylink_registrar(&mut self,
-                        vi: &ast::ViewItem,
+    fn dylink_registrar<'b>(&mut self,
+                        c: CrateOrString<'b>,
                         path: Path,
                         symbol: String) -> PluginRegistrarFun {
         // Make sure the path contains a / or the linker will search for it.
@@ -223,7 +232,13 @@ impl<'a> PluginLoader<'a> {
             // this is fatal: there are almost certainly macros we need
             // inside this crate, so continue would spew "macro undefined"
             // errors
-            Err(err) => self.sess.span_fatal(vi.span, &err[])
+            Err(err) => {
+                if let CrateOrString::Krate(cr) = c {
+                    self.sess.span_fatal(cr.span, &err[])
+                } else {
+                    self.sess.fatal(&err[])
+                }
+            }
         };
 
         unsafe {
@@ -233,7 +248,13 @@ impl<'a> PluginLoader<'a> {
                         mem::transmute::<*mut u8,PluginRegistrarFun>(registrar)
                     }
                     // again fatal if we can't register macros
-                    Err(err) => self.sess.span_fatal(vi.span, &err[])
+                    Err(err) => {
+                        if let CrateOrString::Krate(cr) = c {
+                            self.sess.span_fatal(cr.span, &err[])
+                        } else {
+                            self.sess.fatal(&err[])
+                        }
+                    }
                 };
 
             // Intentionally leak the dynamic library. We can't ever unload it