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creader: Load parts of plugin metadata on demand
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Keegan McAllister committed Jan 6, 2015
1 parent 677b7ca commit f314e2c
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Showing 2 changed files with 125 additions and 82 deletions.
148 changes: 98 additions & 50 deletions src/librustc/metadata/creader.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -16,11 +16,10 @@ use back::svh::Svh;
use session::{config, Session};
use session::search_paths::PathKind;
use metadata::cstore;
use metadata::cstore::{CStore, CrateSource};
use metadata::cstore::{CStore, CrateSource, MetadataBlob};
use metadata::decoder;
use metadata::loader;
use metadata::loader::CratePaths;
use plugin::load::PluginMetadata;
use util::nodemap::FnvHashMap;

use std::rc::Rc;
Expand Down Expand Up @@ -154,6 +153,29 @@ fn register_native_lib(sess: &Session,
sess.cstore.add_used_library(name, kind);
}

pub struct PluginMetadata<'a> {
sess: &'a Session,
metadata: PMDSource,
dylib: Option<Path>,
info: CrateInfo,
vi_span: Span,
target_only: bool,
}

enum PMDSource {
Registered(Rc<cstore::crate_metadata>),
Owned(MetadataBlob),
}

impl PMDSource {
pub fn as_slice<'a>(&'a self) -> &'a [u8] {
match *self {
PMDSource::Registered(ref cmd) => cmd.data(),
PMDSource::Owned(ref mdb) => mdb.as_slice(),
}
}
}

impl<'a> CrateReader<'a> {
pub fn new(sess: &'a Session) -> CrateReader<'a> {
CrateReader {
Expand Down Expand Up @@ -450,17 +472,20 @@ impl<'a> CrateReader<'a> {
}).collect()
}

pub fn read_plugin_metadata(&mut self,
krate: &ast::ViewItem) -> PluginMetadata {
let info = self.extract_crate_info(krate).unwrap();
pub fn read_plugin_metadata<'b>(&'b mut self,
vi: &'b ast::ViewItem) -> PluginMetadata<'b> {
let info = self.extract_crate_info(vi).unwrap();
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;
let mut target_only = false;
let ident = info.ident.clone();
let name = info.name.clone();
let mut load_ctxt = loader::Context {
sess: self.sess,
span: krate.span,
ident: info.ident[],
crate_name: info.name[],
span: vi.span,
ident: ident[],
crate_name: name[],
hash: None,
filesearch: self.sess.host_filesearch(PathKind::Crate),
triple: config::host_triple(),
Expand All @@ -472,32 +497,49 @@ impl<'a> CrateReader<'a> {
let library = match load_ctxt.maybe_load_library_crate() {
Some(l) => l,
None if is_cross => {
// try loading from target crates (only valid if there are
// no syntax extensions)
// Try loading from target crates. This will abort later if we try to
// load a plugin registrar function,
target_only = true;
should_link = info.should_link;

load_ctxt.triple = target_triple;
load_ctxt.filesearch = self.sess.target_filesearch(PathKind::Crate);
let lib = load_ctxt.load_library_crate();
if decoder::get_plugin_registrar_fn(lib.metadata.as_slice()).is_some() {
let message = format!("crate `{}` contains a plugin_registrar fn but \
only a version for triple `{}` could be found (need {})",
info.ident, target_triple, config::host_triple());
self.sess.span_err(krate.span, message[]);
// need to abort now because the syntax expansion
// code will shortly attempt to load and execute
// code from the found library.
self.sess.abort_if_errors();
}
should_link = info.should_link;
lib
load_ctxt.load_library_crate()
}
None => { load_ctxt.report_load_errs(); unreachable!() },
};

// Read exported macros
let imported_from = Some(token::intern(info.ident[]).ident());
let source_name = format!("<{} macros>", info.ident[]);
let dylib = library.dylib.clone();
let register = should_link && self.existing_match(info.name[], None).is_none();
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);
PMDSource::Registered(cmd)
} else {
// Not registering the crate; just hold on to the metadata
PMDSource::Owned(library.metadata)
};

PluginMetadata {
sess: self.sess,
metadata: metadata,
dylib: dylib,
info: info,
vi_span: vi.span,
target_only: target_only,
}
}
}

impl<'a> PluginMetadata<'a> {
/// Read exported macros
pub fn exported_macros(&self) -> Vec<ast::MacroDef> {
let imported_from = Some(token::intern(self.info.ident[]).ident());
let source_name = format!("<{} macros>", self.info.ident[]);
let mut macros = vec![];
decoder::each_exported_macro(library.metadata.as_slice(), &*self.sess.cstore.intr,
decoder::each_exported_macro(self.metadata.as_slice(),
&*self.sess.cstore.intr,
|name, attrs, body| {
// NB: Don't use parse::parse_tts_from_source_str because it parses with
// quote_depth > 0.
Expand All @@ -520,31 +562,37 @@ impl<'a> CrateReader<'a> {
true
}
);
macros
}

// Look for a plugin registrar
let registrar = decoder::get_plugin_registrar_fn(library.metadata.as_slice()).map(|id| {
decoder::get_symbol(library.metadata.as_slice(), id)
});
if library.dylib.is_none() && registrar.is_some() {
let message = format!("plugin crate `{}` only found in rlib format, \
but must be available in dylib format",
info.ident);
self.sess.span_err(krate.span, message[]);
// No need to abort because the loading code will just ignore this
// empty dylib.
/// Look for a plugin registrar. Returns library path and symbol name.
pub fn plugin_registrar(&self) -> Option<(Path, String)> {
if self.target_only {
// Need to abort before syntax expansion.
let message = format!("plugin crate `{}` is not available for triple `{}` \
(only found {})",
self.info.ident,
config::host_triple(),
self.sess.opts.target_triple);
self.sess.span_err(self.vi_span, message[]);
self.sess.abort_if_errors();
}
let pc = PluginMetadata {
macros: macros,
registrar: match (library.dylib.as_ref(), registrar) {
(Some(dylib), Some(reg)) => Some((dylib.clone(), reg)),
_ => None,
},
};
if should_link && self.existing_match(info.name[], None).is_none() {
// register crate now to avoid double-reading metadata
self.register_crate(&None, info.ident[],
info.name[], krate.span, library);

let registrar = decoder::get_plugin_registrar_fn(self.metadata.as_slice())
.map(|id| decoder::get_symbol(self.metadata.as_slice(), id));

match (self.dylib.as_ref(), registrar) {
(Some(dylib), Some(reg)) => Some((dylib.clone(), reg)),
(None, Some(_)) => {
let message = format!("plugin crate `{}` only found in rlib format, \
but must be available in dylib format",
self.info.ident);
self.sess.span_err(self.vi_span, message[]);
// No need to abort because the loading code will just ignore this
// empty dylib.
None
}
_ => None,
}
pc
}
}
59 changes: 27 additions & 32 deletions src/librustc/plugin/load.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -23,14 +23,6 @@ use syntax::visit;
use syntax::visit::Visitor;
use syntax::attr::AttrMetaMethods;

/// Metadata for a single plugin crate.
pub struct PluginMetadata {
/// Macros exported by the crate.
pub macros: Vec<ast::MacroDef>,
/// Path to the shared library file, and registrar function symbol.
pub registrar: Option<(Path, String)>,
}

/// Pointer to a registrar function.
pub type PluginRegistrarFun =
fn(&mut Registry);
Expand Down Expand Up @@ -86,37 +78,40 @@ pub fn load_plugins(sess: &Session, krate: &ast::Crate,
// note that macros aren't expanded yet, and therefore macros can't add plugins.
impl<'a, 'v> Visitor<'v> for PluginLoader<'a> {
fn visit_view_item(&mut self, vi: &ast::ViewItem) {
// We're only interested in `extern crate`.
match vi.node {
ast::ViewItemExternCrate(_, _, _) => {
let mut plugin_phase = false;

for attr in vi.attrs.iter().filter(|a| a.check_name("phase")) {
let phases = attr.meta_item_list().unwrap_or(&[]);
if attr::contains_name(phases, "plugin") {
plugin_phase = true;
}
if attr::contains_name(phases, "syntax") {
plugin_phase = true;
self.sess.span_warn(attr.span,
"phase(syntax) is a deprecated synonym for phase(plugin)");
}
}
ast::ViewItemExternCrate(..) => (),
_ => return,
}

if !plugin_phase { return; }
let mut plugin_phase = false;
for attr in vi.attrs.iter().filter(|a| a.check_name("phase")) {
let phases = attr.meta_item_list().unwrap_or(&[]);
if attr::contains_name(phases, "plugin") {
plugin_phase = true;
}
if attr::contains_name(phases, "syntax") {
plugin_phase = true;
self.sess.span_warn(attr.span,
"phase(syntax) is a deprecated synonym for phase(plugin)");
}
}

let PluginMetadata { macros, registrar } =
self.reader.read_plugin_metadata(vi);
let mut macros = vec![];
let mut registrar = None;

self.plugins.macros.extend(macros.into_iter());
if plugin_phase {
let pmd = self.reader.read_plugin_metadata(vi);
macros = pmd.exported_macros();
registrar = pmd.plugin_registrar();
}

match registrar {
Some((lib, symbol)) => self.dylink_registrar(vi, lib, symbol),
_ => (),
}
}
_ => (),
self.plugins.macros.extend(macros.into_iter());
if let Some((lib, symbol)) = registrar {
self.dylink_registrar(vi, lib, symbol);
}
}

fn visit_mac(&mut self, _: &ast::Mac) {
// bummer... can't see plugins inside macros.
// do nothing.
Expand Down

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