make the metadata lock more robust and bump the metadata encoding version

check the metadata lock when loading rather than afterwards

Fixes rust-lang#33733
Fixes rust-lang#33015

Author: arielb1

src/librustc_metadata/common.rs

@@ -252,3 +252,7 @@ pub fn rustc_version() -> String {
 }
 
 pub const tag_panic_strategy: usize = 0x114;
+
+// NB: increment this if you change the format of metadata such that
+// rustc_version can't be found.
+pub const metadata_encoding_version : &'static [u8] = &[b'r', b'u', b's', b't', 0, 0, 0, 2];

src/librustc_metadata/creader.rs

@@ -12,7 +12,6 @@
 
 //! Validates all used crates and extern libraries and loads their metadata
 
-use common::rustc_version;
 use cstore::{self, CStore, CrateSource, MetadataBlob};
 use decoder;
 use loader::{self, CratePaths};
@@ -234,25 +233,6 @@ impl<'a> CrateReader<'a> {
         return ret;
     }
 
-    fn verify_rustc_version(&self,
-                            name: &str,
-                            span: Span,
-                            metadata: &MetadataBlob) {
-        let crate_rustc_version = decoder::crate_rustc_version(metadata.as_slice());
-        if crate_rustc_version != Some(rustc_version()) {
-            let mut err = struct_span_fatal!(self.sess, span, E0514,
-                                             "the crate `{}` has been compiled with {}, which is \
-                                              incompatible with this version of rustc",
-                                              name,
-                                              crate_rustc_version
-                                              .as_ref().map(|s| &**s)
-                                              .unwrap_or("an old version of rustc"));
-            err.help("consider removing the compiled binaries and recompiling \
-                      with your current version of rustc");
-            err.emit();
-        }
-    }
-
     fn verify_no_symbol_conflicts(&self,
                                   span: Span,
                                   metadata: &MetadataBlob) {
@@ -294,7 +274,6 @@ impl<'a> CrateReader<'a> {
                       explicitly_linked: bool)
                       -> (ast::CrateNum, Rc<cstore::crate_metadata>,
                           cstore::CrateSource) {
-        self.verify_rustc_version(name, span, &lib.metadata);
         self.verify_no_symbol_conflicts(span, &lib.metadata);
 
         // Claim this crate number and cache it
@@ -379,6 +358,7 @@ impl<'a> CrateReader<'a> {
                     rejected_via_hash: vec!(),
                     rejected_via_triple: vec!(),
                     rejected_via_kind: vec!(),
+                    rejected_via_version: vec!(),
                     should_match_name: true,
                 };
                 match self.load(&mut load_ctxt) {
@@ -506,6 +486,7 @@ impl<'a> CrateReader<'a> {
             rejected_via_hash: vec!(),
             rejected_via_triple: vec!(),
             rejected_via_kind: vec!(),
+            rejected_via_version: vec!(),
             should_match_name: true,
         };
         let library = self.load(&mut load_ctxt).or_else(|| {

src/librustc_metadata/csearch.rs

@@ -9,6 +9,7 @@
 // except according to those terms.
 
 use cstore;
+use common;
 use decoder;
 use encoder;
 use loader;
@@ -587,7 +588,7 @@ impl<'tcx> CrateStore<'tcx> for cstore::CStore {
 
     fn metadata_encoding_version(&self) -> &[u8]
     {
-        encoder::metadata_encoding_version
+        common::metadata_encoding_version
     }
 
     /// Returns a map from a sufficiently visible external item (i.e. an external item that is

src/librustc_metadata/encoder.rs

@@ -1851,10 +1851,6 @@ fn encode_panic_strategy(rbml_w: &mut Encoder, ecx: &EncodeContext) {
     }
 }
 
-// NB: Increment this as you change the metadata encoding version.
-#[allow(non_upper_case_globals)]
-pub const metadata_encoding_version : &'static [u8] = &[b'r', b'u', b's', b't', 0, 0, 0, 2 ];
-
 pub fn encode_metadata(ecx: EncodeContext, krate: &hir::Crate) -> Vec<u8> {
     let mut wr = Cursor::new(Vec::new());
 

src/librustc_metadata/loader.rs

@@ -213,8 +213,8 @@
 //! metadata::loader or metadata::creader for all the juicy details!
 
 use cstore::{MetadataBlob, MetadataVec, MetadataArchive};
+use common::{metadata_encoding_version, rustc_version};
 use decoder;
-use encoder;
 
 use rustc::hir::svh::Svh;
 use rustc::session::Session;
@@ -260,6 +260,7 @@ pub struct Context<'a> {
     pub rejected_via_hash: Vec<CrateMismatch>,
     pub rejected_via_triple: Vec<CrateMismatch>,
     pub rejected_via_kind: Vec<CrateMismatch>,
+    pub rejected_via_version: Vec<CrateMismatch>,
     pub should_match_name: bool,
 }
 
@@ -336,6 +337,10 @@ impl<'a> Context<'a> {
             struct_span_err!(self.sess, self.span, E0462,
                              "found staticlib `{}` instead of rlib or dylib{}",
                              self.ident, add)
+        } else if !self.rejected_via_version.is_empty() {
+            struct_span_err!(self.sess, self.span, E0514,
+                             "found crate `{}` compiled by an incompatible version of rustc{}",
+                             self.ident, add)
         } else {
             struct_span_err!(self.sess, self.span, E0463,
                              "can't find crate for `{}`{}",
@@ -350,7 +355,7 @@ impl<'a> Context<'a> {
             }
         }
         if !self.rejected_via_hash.is_empty() {
-            err.note("perhaps this crate needs to be recompiled?");
+            err.note("perhaps that crate needs to be recompiled?");
             let mismatches = self.rejected_via_hash.iter();
             for (i, &CrateMismatch{ ref path, .. }) in mismatches.enumerate() {
                 err.note(&format!("crate `{}` path #{}: {}",
@@ -367,13 +372,22 @@ impl<'a> Context<'a> {
             }
         }
         if !self.rejected_via_kind.is_empty() {
-            err.help("please recompile this crate using --crate-type lib");
+            err.help("please recompile that crate using --crate-type lib");
             let mismatches = self.rejected_via_kind.iter();
             for (i, &CrateMismatch { ref path, .. }) in mismatches.enumerate() {
                 err.note(&format!("crate `{}` path #{}: {}",
                                   self.ident, i+1, path.display()));
             }
         }
+        if !self.rejected_via_version.is_empty() {
+            err.help(&format!("please recompile that crate using this compiler ({})",
+                              rustc_version()));
+            let mismatches = self.rejected_via_version.iter();
+            for (i, &CrateMismatch { ref path, ref got }) in mismatches.enumerate() {
+                err.note(&format!("crate `{}` path #{}: {} compiled by {:?}",
+                                  self.ident, i+1, path.display(), got));
+            }
+        }
 
         err.emit();
         self.sess.abort_if_errors();
@@ -591,6 +605,17 @@ impl<'a> Context<'a> {
     }
 
     fn crate_matches(&mut self, crate_data: &[u8], libpath: &Path) -> Option<Svh> {
+        let crate_rustc_version = decoder::crate_rustc_version(crate_data);
+        if crate_rustc_version != Some(rustc_version()) {
+            let message = crate_rustc_version.unwrap_or(format!("an unknown compiler"));
+            info!("Rejecting via version: expected {} got {}", rustc_version(), message);
+            self.rejected_via_version.push(CrateMismatch {
+                path: libpath.to_path_buf(),
+                got: message
+            });
+            return None;
+        }
+
         if self.should_match_name {
             match decoder::maybe_get_crate_name(crate_data) {
                 Some(ref name) if self.crate_name == *name => {}
@@ -801,12 +826,12 @@ fn get_metadata_section_imp(target: &Target, flavor: CrateFlavor, filename: &Pat
                 let cbuf = llvm::LLVMGetSectionContents(si.llsi);
                 let csz = llvm::LLVMGetSectionSize(si.llsi) as usize;
                 let cvbuf: *const u8 = cbuf as *const u8;
-                let vlen = encoder::metadata_encoding_version.len();
+                let vlen = metadata_encoding_version.len();
                 debug!("checking {} bytes of metadata-version stamp",
                        vlen);
                 let minsz = cmp::min(vlen, csz);
                 let buf0 = slice::from_raw_parts(cvbuf, minsz);
-                let version_ok = buf0 == encoder::metadata_encoding_version;
+                let version_ok = buf0 == metadata_encoding_version;
                 if !version_ok {
                     return Err((format!("incompatible metadata version found: '{}'",
                                         filename.display())));