Auto merge of #68474 - tmandry:rollup-6gmbet6, r=tmandry

Rollup of 10 pull requests

Successful merges:

 - #67195 ([experiment] Add `-Z no-link` flag)
 - #68253 (add bare metal ARM Cortex-A targets to rustc)
 - #68361 (Unbreak linking with lld 9 on FreeBSD 13.0-CURRENT i386)
 - #68388 (Make `TooGeneric` error in WF checking a proper error)
 - #68409 (Micro-optimize OutputFilenames)
 - #68410 (Export weak symbols used by MemorySanitizer)
 - #68425 (Fix try-op diagnostic in E0277 for methods)
 - #68440 (bootstrap: update clippy subcmd decription)
 - #68441 (pprust: use as_deref)
 - #68462 (librustc_mir: don't allocate vectors where slices will do.)

Failed merges:

r? @ghost

Cargo.lock

@@ -3428,6 +3428,7 @@ dependencies = [
  "rustc_session",
  "rustc_span",
  "rustc_target",
+ "serialize",
  "smallvec 1.0.0",
  "syntax",
 ]

src/bootstrap/flags.rs

@@ -104,7 +104,7 @@ Usage: x.py <subcommand> [options] [<paths>...]
 Subcommands:
     build       Compile either the compiler or libraries
     check       Compile either the compiler or libraries, using cargo check
-    clippy      Run clippy
+    clippy      Run clippy (uses rustup/cargo-installed clippy binary)
     fix         Run cargo fix
     fmt         Run rustfmt
     test        Build and run some test suites

src/ci/docker/dist-various-1/Dockerfile

@@ -160,6 +160,7 @@ ENV TARGETS=$TARGETS,armebv7r-none-eabihf
 ENV TARGETS=$TARGETS,armv7r-none-eabi
 ENV TARGETS=$TARGETS,armv7r-none-eabihf
 ENV TARGETS=$TARGETS,thumbv7neon-unknown-linux-gnueabihf
+ENV TARGETS=$TARGETS,armv7a-none-eabi
 
 # riscv targets currently do not need a C compiler, as compiler_builtins
 # doesn't currently have it enabled, and the riscv gcc compiler is not
@@ -173,6 +174,10 @@ ENV CC_mipsel_unknown_linux_musl=mipsel-openwrt-linux-gcc \
     CC_thumbv7neon_unknown_linux_gnueabihf=arm-linux-gnueabihf-gcc \
     AR_thumbv7neon_unknown_linux_gnueabihf=arm-linux-gnueabihf-ar \
     CXX_thumbv7neon_unknown_linux_gnueabihf=arm-linux-gnueabihf-g++ \
+    CC_armv7a_none_eabi=arm-none-eabi-gcc \
+    CC_armv7a_none_eabihf=arm-none-eabi-gcc \
+    CFLAGS_armv7a_none_eabi=-march=armv7-a \
+    CFLAGS_armv7a_none_eabihf=-march=armv7-a+vfpv3 \
     CC_riscv64gc_unknown_linux_gnu=riscv64-unknown-linux-gnu-gcc \
     AR_riscv64gc_unknown_linux_gnu=riscv64-unknown-linux-gnu-ar \
     CXX_riscv64gc_unknown_linux_gnu=riscv64-unknown-linux-gnu-g++ \

src/librustc/middle/cstore.rs

@@ -27,7 +27,7 @@ pub use rustc_session::utils::NativeLibraryKind;
 
 /// Where a crate came from on the local filesystem. One of these three options
 /// must be non-None.
-#[derive(PartialEq, Clone, Debug, HashStable)]
+#[derive(PartialEq, Clone, Debug, HashStable, RustcEncodable, RustcDecodable)]
 pub struct CrateSource {
     pub dylib: Option<(PathBuf, PathKind)>,
     pub rlib: Option<(PathBuf, PathKind)>,
@@ -75,7 +75,7 @@ impl DepKind {
     }
 }
 
-#[derive(PartialEq, Clone, Debug)]
+#[derive(PartialEq, Clone, Debug, RustcEncodable, RustcDecodable)]
 pub enum LibSource {
     Some(PathBuf),
     MetadataOnly,
@@ -160,6 +160,7 @@ pub enum ExternCrateSource {
     Path,
 }
 
+#[derive(RustcEncodable, RustcDecodable)]
 pub struct EncodedMetadata {
     pub raw_data: Vec<u8>,
 }

src/librustc/middle/dependency_format.rs

@@ -19,7 +19,7 @@ pub type DependencyList = Vec<Linkage>;
 /// This is local to the tcx, and is generally relevant to one session.
 pub type Dependencies = Vec<(config::CrateType, DependencyList)>;
 
-#[derive(Copy, Clone, PartialEq, Debug, HashStable)]
+#[derive(Copy, Clone, PartialEq, Debug, HashStable, RustcEncodable, RustcDecodable)]
 pub enum Linkage {
     NotLinked,
     IncludedFromDylib,

src/librustc/traits/error_reporting/mod.rs

@@ -919,17 +919,29 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 report_object_safety_error(self.tcx, span, did, violations)
             }
 
-            // already reported in the query
-            ConstEvalFailure(err) => {
-                if let ErrorHandled::TooGeneric = err {
-                    // Silence this error, as it can be produced during intermediate steps
-                    // when a constant is not yet able to be evaluated (but will be later).
-                    return;
-                }
-                self.tcx.sess.delay_span_bug(
-                    span,
-                    &format!("constant in type had an ignored error: {:?}", err),
-                );
+            ConstEvalFailure(ErrorHandled::TooGeneric) => {
+                // In this instance, we have a const expression containing an unevaluated
+                // generic parameter. We have no idea whether this expression is valid or
+                // not (e.g. it might result in an error), but we don't want to just assume
+                // that it's okay, because that might result in post-monomorphisation time
+                // errors. The onus is really on the caller to provide values that it can
+                // prove are well-formed.
+                let mut err = self
+                    .tcx
+                    .sess
+                    .struct_span_err(span, "constant expression depends on a generic parameter");
+                // FIXME(const_generics): we should suggest to the user how they can resolve this
+                // issue. However, this is currently not actually possible
+                // (see https://github.com/rust-lang/rust/issues/66962#issuecomment-575907083).
+                err.note("this may fail depending on what value the parameter takes");
+                err
+            }
+
+            // Already reported in the query.
+            ConstEvalFailure(ErrorHandled::Reported) => {
+                self.tcx
+                    .sess
+                    .delay_span_bug(span, &format!("constant in type had an ignored error"));
                 return;
             }
 

src/librustc/traits/error_reporting/on_unimplemented.rs

@@ -59,31 +59,45 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     fn describe_enclosure(&self, hir_id: hir::HirId) -> Option<&'static str> {
         let hir = &self.tcx.hir();
         let node = hir.find(hir_id)?;
-        if let hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(sig, _, body_id), .. }) = &node {
-            self.describe_generator(*body_id).or_else(|| {
+        match &node {
+            hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(sig, _, body_id), .. }) => {
+                self.describe_generator(*body_id).or_else(|| {
+                    Some(if let hir::FnHeader { asyncness: hir::IsAsync::Async, .. } = sig.header {
+                        "an async function"
+                    } else {
+                        "a function"
+                    })
+                })
+            }
+            hir::Node::TraitItem(hir::TraitItem {
+                kind: hir::TraitItemKind::Method(_, hir::TraitMethod::Provided(body_id)),
+                ..
+            }) => self.describe_generator(*body_id).or_else(|| Some("a trait method")),
+            hir::Node::ImplItem(hir::ImplItem {
+                kind: hir::ImplItemKind::Method(sig, body_id),
+                ..
+            }) => self.describe_generator(*body_id).or_else(|| {
                 Some(if let hir::FnHeader { asyncness: hir::IsAsync::Async, .. } = sig.header {
-                    "an async function"
+                    "an async method"
                 } else {
-                    "a function"
+                    "a method"
                 })
-            })
-        } else if let hir::Node::Expr(hir::Expr {
-            kind: hir::ExprKind::Closure(_is_move, _, body_id, _, gen_movability),
-            ..
-        }) = &node
-        {
-            self.describe_generator(*body_id).or_else(|| {
+            }),
+            hir::Node::Expr(hir::Expr {
+                kind: hir::ExprKind::Closure(_is_move, _, body_id, _, gen_movability),
+                ..
+            }) => self.describe_generator(*body_id).or_else(|| {
                 Some(if gen_movability.is_some() { "an async closure" } else { "a closure" })
-            })
-        } else if let hir::Node::Expr(hir::Expr { .. }) = &node {
-            let parent_hid = hir.get_parent_node(hir_id);
-            if parent_hid != hir_id {
-                return self.describe_enclosure(parent_hid);
-            } else {
-                None
+            }),
+            hir::Node::Expr(hir::Expr { .. }) => {
+                let parent_hid = hir.get_parent_node(hir_id);
+                if parent_hid != hir_id {
+                    return self.describe_enclosure(parent_hid);
+                } else {
+                    None
+                }
             }
-        } else {
-            None
+            _ => None,
         }
     }
 

src/librustc_codegen_llvm/Cargo.toml

@@ -28,6 +28,7 @@ rustc_incremental = { path = "../librustc_incremental" }
 rustc_index = { path = "../librustc_index" }
 rustc_llvm = { path = "../librustc_llvm" }
 rustc_session = { path = "../librustc_session" }
+rustc_serialize = { path = "../libserialize", package = "serialize" }
 rustc_target = { path = "../librustc_target" }
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
 syntax = { path = "../libsyntax" }

src/librustc_codegen_llvm/lib.rs

@@ -33,6 +33,7 @@ use rustc_codegen_ssa::CompiledModule;
 use rustc_errors::{FatalError, Handler};
 use std::any::Any;
 use std::ffi::CStr;
+use std::fs;
 use std::sync::Arc;
 use syntax::expand::allocator::AllocatorKind;
 
@@ -44,6 +45,7 @@ use rustc::ty::{self, TyCtxt};
 use rustc::util::common::ErrorReported;
 use rustc_codegen_ssa::ModuleCodegen;
 use rustc_codegen_utils::codegen_backend::CodegenBackend;
+use rustc_serialize::json;
 
 mod back {
     pub mod archive;
@@ -298,6 +300,18 @@ impl CodegenBackend for LlvmCodegenBackend {
             return Ok(());
         }
 
+        if sess.opts.debugging_opts.no_link {
+            // FIXME: use a binary format to encode the `.rlink` file
+            let rlink_data = json::encode(&codegen_results).map_err(|err| {
+                sess.fatal(&format!("failed to encode rlink: {}", err));
+            })?;
+            let rlink_file = outputs.with_extension("rlink");
+            fs::write(&rlink_file, rlink_data).map_err(|err| {
+                sess.fatal(&format!("failed to write file {}: {}", rlink_file.display(), err));
+            })?;
+            return Ok(());
+        }
+
         // Run the linker on any artifacts that resulted from the LLVM run.
         // This should produce either a finished executable or library.
         sess.time("link_crate", || {

src/librustc_codegen_ssa/back/linker.rs

@@ -20,6 +20,7 @@ use rustc_target::spec::{LinkerFlavor, LldFlavor};
 
 /// For all the linkers we support, and information they might
 /// need out of the shared crate context before we get rid of it.
+#[derive(RustcEncodable, RustcDecodable)]
 pub struct LinkerInfo {
     exports: FxHashMap<CrateType, Vec<String>>,
 }

src/librustc_codegen_ssa/back/symbol_export.rs

@@ -3,7 +3,7 @@ use std::sync::Arc;
 
 use rustc::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc::middle::exported_symbols::{metadata_symbol_name, ExportedSymbol, SymbolExportLevel};
-use rustc::session::config;
+use rustc::session::config::{self, Sanitizer};
 use rustc::ty::query::Providers;
 use rustc::ty::subst::SubstsRef;
 use rustc::ty::Instance;
@@ -206,6 +206,16 @@ fn exported_symbols_provider_local(
         }));
     }
 
+    if let Some(Sanitizer::Memory) = tcx.sess.opts.debugging_opts.sanitizer {
+        // Similar to profiling, preserve weak msan symbol during LTO.
+        const MSAN_WEAK_SYMBOLS: [&str; 2] = ["__msan_track_origins", "__msan_keep_going"];
+
+        symbols.extend(MSAN_WEAK_SYMBOLS.iter().map(|sym| {
+            let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(sym));
+            (exported_symbol, SymbolExportLevel::C)
+        }));
+    }
+
     if tcx.sess.crate_types.borrow().contains(&config::CrateType::Dylib) {
         let symbol_name = metadata_symbol_name(tcx);
         let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(&symbol_name));

src/librustc_codegen_ssa/lib.rs

@@ -87,7 +87,7 @@ impl<M> ModuleCodegen<M> {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, RustcEncodable, RustcDecodable)]
 pub struct CompiledModule {
     pub name: String,
     pub kind: ModuleKind,
@@ -101,7 +101,7 @@ pub struct CachedModuleCodegen {
     pub source: WorkProduct,
 }
 
-#[derive(Copy, Clone, Debug, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq, RustcEncodable, RustcDecodable)]
 pub enum ModuleKind {
     Regular,
     Metadata,
@@ -117,7 +117,14 @@ bitflags::bitflags! {
 }
 
 /// Misc info we load from metadata to persist beyond the tcx.
-#[derive(Debug)]
+///
+/// Note: though `CrateNum` is only meaningful within the same tcx, information within `CrateInfo`
+/// is self-contained. `CrateNum` can be viewed as a unique identifier within a `CrateInfo`, where
+/// `used_crate_source` contains all `CrateSource` of the dependents, and maintains a mapping from
+/// identifiers (`CrateNum`) to `CrateSource`. The other fields map `CrateNum` to the crate's own
+/// additional properties, so that effectively we can retrieve each dependent crate's `CrateSource`
+/// and the corresponding properties without referencing information outside of a `CrateInfo`.
+#[derive(Debug, RustcEncodable, RustcDecodable)]
 pub struct CrateInfo {
     pub panic_runtime: Option<CrateNum>,
     pub compiler_builtins: Option<CrateNum>,
@@ -135,6 +142,7 @@ pub struct CrateInfo {
     pub dependency_formats: Lrc<Dependencies>,
 }
 
+#[derive(RustcEncodable, RustcDecodable)]
 pub struct CodegenResults {
     pub crate_name: Symbol,
     pub modules: Vec<CompiledModule>,

src/librustc_hir/def_id.rs

@@ -1,7 +1,8 @@
 use rustc_data_structures::AtomicRef;
 use rustc_index::vec::Idx;
+use rustc_serialize::{Decoder, Encoder};
 use std::fmt;
-use std::u32;
+use std::{u32, u64};
 
 rustc_index::newtype_index! {
     pub struct CrateId {
@@ -86,8 +87,18 @@ impl fmt::Display for CrateNum {
     }
 }
 
-impl rustc_serialize::UseSpecializedEncodable for CrateNum {}
-impl rustc_serialize::UseSpecializedDecodable for CrateNum {}
+/// As a local identifier, a `CrateNum` is only meaningful within its context, e.g. within a tcx.
+/// Therefore, make sure to include the context when encode a `CrateNum`.
+impl rustc_serialize::UseSpecializedEncodable for CrateNum {
+    fn default_encode<E: Encoder>(&self, e: &mut E) -> Result<(), E::Error> {
+        e.emit_u32(self.as_u32())
+    }
+}
+impl rustc_serialize::UseSpecializedDecodable for CrateNum {
+    fn default_decode<D: Decoder>(d: &mut D) -> Result<CrateNum, D::Error> {
+        Ok(CrateNum::from_u32(d.read_u32()?))
+    }
+}
 
 rustc_index::newtype_index! {
     /// A DefIndex is an index into the hir-map for a crate, identifying a
@@ -135,8 +146,21 @@ impl DefId {
     }
 }
 
-impl rustc_serialize::UseSpecializedEncodable for DefId {}
-impl rustc_serialize::UseSpecializedDecodable for DefId {}
+impl rustc_serialize::UseSpecializedEncodable for DefId {
+    fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
+        let krate = u64::from(self.krate.as_u32());
+        let index = u64::from(self.index.as_u32());
+        s.emit_u64((krate << 32) | index)
+    }
+}
+impl rustc_serialize::UseSpecializedDecodable for DefId {
+    fn default_decode<D: Decoder>(d: &mut D) -> Result<DefId, D::Error> {
+        let def_id = d.read_u64()?;
+        let krate = CrateNum::from_u32((def_id >> 32) as u32);
+        let index = DefIndex::from_u32((def_id & 0xffffffff) as u32);
+        Ok(DefId { krate, index })
+    }
+}
 
 pub fn default_def_id_debug(def_id: DefId, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     f.debug_struct("DefId").field("krate", &def_id.krate).field("index", &def_id.index).finish()

src/librustc_interface/util.rs

@@ -550,13 +550,13 @@ pub fn build_output_filenames(
                 .or_else(|| attr::find_crate_name(attrs).map(|n| n.to_string()))
                 .unwrap_or_else(|| input.filestem().to_owned());
 
-            OutputFilenames {
-                out_directory: dirpath,
-                out_filestem: stem,
-                single_output_file: None,
-                extra: sess.opts.cg.extra_filename.clone(),
-                outputs: sess.opts.output_types.clone(),
-            }
+            OutputFilenames::new(
+                dirpath,
+                stem,
+                None,
+                sess.opts.cg.extra_filename.clone(),
+                sess.opts.output_types.clone(),
+            )
         }
 
         Some(ref out_file) => {
@@ -578,18 +578,13 @@ pub fn build_output_filenames(
                 sess.warn("ignoring --out-dir flag due to -o flag");
             }
 
-            OutputFilenames {
-                out_directory: out_file.parent().unwrap_or_else(|| Path::new("")).to_path_buf(),
-                out_filestem: out_file
-                    .file_stem()
-                    .unwrap_or_default()
-                    .to_str()
-                    .unwrap()
-                    .to_string(),
-                single_output_file: ofile,
-                extra: sess.opts.cg.extra_filename.clone(),
-                outputs: sess.opts.output_types.clone(),
-            }
+            OutputFilenames::new(
+                out_file.parent().unwrap_or_else(|| Path::new("")).to_path_buf(),
+                out_file.file_stem().unwrap_or_default().to_str().unwrap().to_string(),
+                ofile,
+                sess.opts.cg.extra_filename.clone(),
+                sess.opts.output_types.clone(),
+            )
         }
     }
 }