Auto merge of #48904 - Zoxc:code-and-file-maps, r=michaelwoerister

Make CodeMap and FileMap thread-safe

r? @michaelwoerister

1 files changed, 40 insertions, 38 deletions

diff --git a/src/libsyntax/codemap.rs b/src/libsyntax/codemap.rs
index 951f8a871ca..a1aec052088 100644
--- a/src/libsyntax/codemap.rs
+++ b/src/libsyntax/codemap.rs
@@ -24,8 +24,7 @@ pub use self::ExpnFormat::*;
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stable_hasher::StableHasher;
-use rustc_data_structures::sync::Lrc;
-use std::cell::{RefCell, Ref};
+use rustc_data_structures::sync::{Lrc, Lock, LockGuard};
 use std::cmp;
 use std::hash::Hash;
 use std::path::{Path, PathBuf};
@@ -125,13 +124,17 @@ impl StableFilemapId {
 // CodeMap
 //
 
+pub(super) struct CodeMapFiles {
+    pub(super) file_maps: Vec<Lrc<FileMap>>,
+    stable_id_to_filemap: FxHashMap<StableFilemapId, Lrc<FileMap>>
+}
+
 pub struct CodeMap {
-    pub(super) files: RefCell<Vec<Lrc<FileMap>>>,
-    file_loader: Box<FileLoader>,
+    pub(super) files: Lock<CodeMapFiles>,
+    file_loader: Box<FileLoader + Sync + Send>,
     // This is used to apply the file path remapping as specified via
     // --remap-path-prefix to all FileMaps allocated within this CodeMap.
     path_mapping: FilePathMapping,
-    stable_id_to_filemap: RefCell<FxHashMap<StableFilemapId, Lrc<FileMap>>>,
     /// In case we are in a doctest, replace all file names with the PathBuf,
     /// and add the given offsets to the line info
     doctest_offset: Option<(FileName, isize)>,
@@ -140,10 +143,12 @@ pub struct CodeMap {
 impl CodeMap {
     pub fn new(path_mapping: FilePathMapping) -> CodeMap {
         CodeMap {
-            files: RefCell::new(Vec::new()),
+            files: Lock::new(CodeMapFiles {
+                file_maps: Vec::new(),
+                stable_id_to_filemap: FxHashMap(),
+            }),
             file_loader: Box::new(RealFileLoader),
             path_mapping,
-            stable_id_to_filemap: RefCell::new(FxHashMap()),
             doctest_offset: None,
         }
     }
@@ -157,14 +162,16 @@ impl CodeMap {
 
     }
 
-    pub fn with_file_loader(file_loader: Box<FileLoader>,
+    pub fn with_file_loader(file_loader: Box<FileLoader + Sync + Send>,
                             path_mapping: FilePathMapping)
                             -> CodeMap {
         CodeMap {
-            files: RefCell::new(Vec::new()),
-            file_loader,
+            files: Lock::new(CodeMapFiles {
+                file_maps: Vec::new(),
+                stable_id_to_filemap: FxHashMap(),
+            }),
+            file_loader: file_loader,
             path_mapping,
-            stable_id_to_filemap: RefCell::new(FxHashMap()),
             doctest_offset: None,
         }
     }
@@ -187,17 +194,16 @@ impl CodeMap {
         Ok(self.new_filemap(filename, src))
     }
 
-    pub fn files(&self) -> Ref<Vec<Lrc<FileMap>>> {
-        self.files.borrow()
+    pub fn files(&self) -> LockGuard<Vec<Lrc<FileMap>>> {
+        LockGuard::map(self.files.borrow(), |files| &mut files.file_maps)
     }
 
     pub fn filemap_by_stable_id(&self, stable_id: StableFilemapId) -> Option<Lrc<FileMap>> {
-        self.stable_id_to_filemap.borrow().get(&stable_id).map(|fm| fm.clone())
+        self.files.borrow().stable_id_to_filemap.get(&stable_id).map(|fm| fm.clone())
     }
 
     fn next_start_pos(&self) -> usize {
-        let files = self.files.borrow();
-        match files.last() {
+        match self.files.borrow().file_maps.last() {
             None => 0,
             // Add one so there is some space between files. This lets us distinguish
             // positions in the codemap, even in the presence of zero-length files.
@@ -207,9 +213,9 @@ impl CodeMap {
 
     /// Creates a new filemap without setting its line information. If you don't
     /// intend to set the line information yourself, you should use new_filemap_and_lines.
+    /// This does not ensure that only one FileMap exists per file name.
     pub fn new_filemap(&self, filename: FileName, src: String) -> Lrc<FileMap> {
         let start_pos = self.next_start_pos();
-        let mut files = self.files.borrow_mut();
 
         // The path is used to determine the directory for loading submodules and
         // include files, so it must be before remapping.
@@ -233,16 +239,16 @@ impl CodeMap {
             Pos::from_usize(start_pos),
         ));
 
-        files.push(filemap.clone());
+        let mut files = self.files.borrow_mut();
 
-        self.stable_id_to_filemap
-            .borrow_mut()
-            .insert(StableFilemapId::new(&filemap), filemap.clone());
+        files.file_maps.push(filemap.clone());
+        files.stable_id_to_filemap.insert(StableFilemapId::new(&filemap), filemap.clone());
 
         filemap
     }
 
     /// Creates a new filemap and sets its line information.
+    /// This does not ensure that only one FileMap exists per file name.
     pub fn new_filemap_and_lines(&self, filename: &Path, src: &str) -> Lrc<FileMap> {
         let fm = self.new_filemap(filename.to_owned().into(), src.to_owned());
         let mut byte_pos: u32 = fm.start_pos.0;
@@ -273,7 +279,6 @@ impl CodeMap {
                                 mut file_local_non_narrow_chars: Vec<NonNarrowChar>)
                                 -> Lrc<FileMap> {
         let start_pos = self.next_start_pos();
-        let mut files = self.files.borrow_mut();
 
         let end_pos = Pos::from_usize(start_pos + source_len);
         let start_pos = Pos::from_usize(start_pos);
@@ -297,20 +302,19 @@ impl CodeMap {
             crate_of_origin,
             src: None,
             src_hash,
-            external_src: RefCell::new(ExternalSource::AbsentOk),
+            external_src: Lock::new(ExternalSource::AbsentOk),
             start_pos,
             end_pos,
-            lines: RefCell::new(file_local_lines),
-            multibyte_chars: RefCell::new(file_local_multibyte_chars),
-            non_narrow_chars: RefCell::new(file_local_non_narrow_chars),
+            lines: Lock::new(file_local_lines),
+            multibyte_chars: Lock::new(file_local_multibyte_chars),
+            non_narrow_chars: Lock::new(file_local_non_narrow_chars),
             name_hash,
         });
 
-        files.push(filemap.clone());
+        let mut files = self.files.borrow_mut();
 
-        self.stable_id_to_filemap
-            .borrow_mut()
-            .insert(StableFilemapId::new(&filemap), filemap.clone());
+        files.file_maps.push(filemap.clone());
+        files.stable_id_to_filemap.insert(StableFilemapId::new(&filemap), filemap.clone());
 
         filemap
     }
@@ -401,8 +405,7 @@ impl CodeMap {
     pub fn lookup_line(&self, pos: BytePos) -> Result<FileMapAndLine, Lrc<FileMap>> {
         let idx = self.lookup_filemap_idx(pos);
 
-        let files = self.files.borrow();
-        let f = (*files)[idx].clone();
+        let f = (*self.files.borrow().file_maps)[idx].clone();
 
         match f.lookup_line(pos) {
             Some(line) => Ok(FileMapAndLine { fm: f, line: line }),
@@ -456,7 +459,7 @@ impl CodeMap {
     }
 
     pub fn span_to_string(&self, sp: Span) -> String {
-        if self.files.borrow().is_empty() && sp.source_equal(&DUMMY_SP) {
+        if self.files.borrow().file_maps.is_empty() && sp.source_equal(&DUMMY_SP) {
             return "no-location".to_string();
         }
 
@@ -799,7 +802,7 @@ impl CodeMap {
     }
 
     pub fn get_filemap(&self, filename: &FileName) -> Option<Lrc<FileMap>> {
-        for fm in self.files.borrow().iter() {
+        for fm in self.files.borrow().file_maps.iter() {
             if *filename == fm.name {
                 return Some(fm.clone());
             }
@@ -810,7 +813,7 @@ impl CodeMap {
     /// For a global BytePos compute the local offset within the containing FileMap
     pub fn lookup_byte_offset(&self, bpos: BytePos) -> FileMapAndBytePos {
         let idx = self.lookup_filemap_idx(bpos);
-        let fm = (*self.files.borrow())[idx].clone();
+        let fm = (*self.files.borrow().file_maps)[idx].clone();
         let offset = bpos - fm.start_pos;
         FileMapAndBytePos {fm: fm, pos: offset}
     }
@@ -818,8 +821,7 @@ impl CodeMap {
     /// Converts an absolute BytePos to a CharPos relative to the filemap.
     pub fn bytepos_to_file_charpos(&self, bpos: BytePos) -> CharPos {
         let idx = self.lookup_filemap_idx(bpos);
-        let files = self.files.borrow();
-        let map = &(*files)[idx];
+        let map = &(*self.files.borrow().file_maps)[idx];
 
         // The number of extra bytes due to multibyte chars in the FileMap
         let mut total_extra_bytes = 0;
@@ -845,7 +847,7 @@ impl CodeMap {
     // Return the index of the filemap (in self.files) which contains pos.
     pub fn lookup_filemap_idx(&self, pos: BytePos) -> usize {
         let files = self.files.borrow();
-        let files = &*files;
+        let files = &files.file_maps;
         let count = files.len();
 
         // Binary search for the filemap.