Auto merge of #40091 - eddyb:rollup, r=eddyb

Rollup of 28 pull requests

- Successful merges: #39859, #39864, #39888, #39903, #39905, #39914, #39945, #39950, #39953, #39961, #39980, #39988, #39993, #39995, #40019, #40020, #40022, #40024, #40025, #40026, #40027, #40031, #40035, #40037, #40038, #40064, #40069, #40086
- Failed merges: #39927, #40008, #40047

Author: bors

src/bootstrap/bin/rustc.rs

@@ -68,6 +68,7 @@ fn main() {
     };
     let stage = env::var("RUSTC_STAGE").expect("RUSTC_STAGE was not set");
     let sysroot = env::var_os("RUSTC_SYSROOT").expect("RUSTC_SYSROOT was not set");
+    let mut on_fail = env::var_os("RUSTC_ON_FAIL").map(|of| Command::new(of));
 
     let rustc = env::var_os(rustc).unwrap_or_else(|| panic!("{:?} was not set", rustc));
     let libdir = env::var_os(libdir).unwrap_or_else(|| panic!("{:?} was not set", libdir));
@@ -217,9 +218,20 @@ fn main() {
     }
 
     // Actually run the compiler!
-    std::process::exit(match exec_cmd(&mut cmd) {
-        Ok(s) => s.code().unwrap_or(0xfe),
-        Err(e) => panic!("\n\nfailed to run {:?}: {}\n\n", cmd, e),
+    std::process::exit(if let Some(ref mut on_fail) = on_fail {
+        match cmd.status() {
+            Ok(s) if s.success() => 0,
+            _ => {
+                println!("\nDid not run successfully:\n{:?}\n-------------", cmd);
+                exec_cmd(on_fail).expect("could not run the backup command");
+                1
+            }
+        }
+    } else {
+        std::process::exit(match exec_cmd(&mut cmd) {
+            Ok(s) => s.code().unwrap_or(0xfe),
+            Err(e) => panic!("\n\nfailed to run {:?}: {}\n\n", cmd, e),
+        })
     })
 }
 

src/bootstrap/bootstrap.py

@@ -355,8 +355,12 @@ def build_bootstrap(self):
         env = os.environ.copy()
         env["CARGO_TARGET_DIR"] = build_dir
         env["RUSTC"] = self.rustc()
-        env["LD_LIBRARY_PATH"] = os.path.join(self.bin_root(), "lib")
-        env["DYLD_LIBRARY_PATH"] = os.path.join(self.bin_root(), "lib")
+        env["LD_LIBRARY_PATH"] = os.path.join(self.bin_root(), "lib") + \
+                                 (os.pathsep + env["LD_LIBRARY_PATH"]) \
+                                 if "LD_LIBRARY_PATH" in env else ""
+        env["DYLD_LIBRARY_PATH"] = os.path.join(self.bin_root(), "lib") + \
+                                   (os.pathsep + env["DYLD_LIBRARY_PATH"]) \
+                                   if "DYLD_LIBRARY_PATH" in env else ""
         env["PATH"] = os.path.join(self.bin_root(), "bin") + \
                       os.pathsep + env["PATH"]
         if not os.path.isfile(self.cargo()):
@@ -485,6 +489,8 @@ def build_triple(self):
             ostype += 'abi64'
         elif cputype in {'powerpc', 'ppc', 'ppc64'}:
             cputype = 'powerpc'
+        elif cputype == 'sparcv9':
+            pass
         elif cputype in {'amd64', 'x86_64', 'x86-64', 'x64'}:
             cputype = 'x86_64'
         else:

src/bootstrap/flags.rs

@@ -28,6 +28,7 @@ use step;
 /// Deserialized version of all flags for this compile.
 pub struct Flags {
     pub verbose: usize, // verbosity level: 0 == not verbose, 1 == verbose, 2 == very verbose
+    pub on_fail: Option<String>,
     pub stage: Option<u32>,
     pub keep_stage: Option<u32>,
     pub build: String,
@@ -81,6 +82,7 @@ impl Flags {
         opts.optopt("", "build", "build target of the stage0 compiler", "BUILD");
         opts.optmulti("", "host", "host targets to build", "HOST");
         opts.optmulti("", "target", "target targets to build", "TARGET");
+        opts.optopt("", "on-fail", "command to run on failure", "CMD");
         opts.optopt("", "stage", "stage to build", "N");
         opts.optopt("", "keep-stage", "stage to keep without recompiling", "N");
         opts.optopt("", "src", "path to the root of the rust checkout", "DIR");
@@ -283,6 +285,7 @@ To learn more about a subcommand, run `./x.py <command> -h`
         Flags {
             verbose: m.opt_count("v"),
             stage: stage,
+            on_fail: m.opt_str("on-fail"),
             keep_stage: m.opt_str("keep-stage").map(|j| j.parse().unwrap()),
             build: m.opt_str("build").unwrap_or_else(|| {
                 env::var("BUILD").unwrap()

src/bootstrap/lib.rs

@@ -499,6 +499,10 @@ impl Build {
             cargo.env("RUSTC_INCREMENTAL", incr_dir);
         }
 
+        if let Some(ref on_fail) = self.flags.on_fail {
+            cargo.env("RUSTC_ON_FAIL", on_fail);
+        }
+
         let verbose = cmp::max(self.config.verbose, self.flags.verbose);
         cargo.env("RUSTC_VERBOSE", format!("{}", verbose));
 
@@ -828,17 +832,6 @@ impl Build {
         if target.contains("apple-darwin") {
             base.push("-stdlib=libc++".into());
         }
-        // This is a hack, because newer binutils broke things on some vms/distros
-        // (i.e., linking against unknown relocs disabled by the following flag)
-        // See: https://github.com/rust-lang/rust/issues/34978
-        match target {
-            "i586-unknown-linux-gnu" |
-            "i686-unknown-linux-musl" |
-            "x86_64-unknown-linux-musl" => {
-                base.push("-Wa,-mrelax-relocations=no".into());
-            },
-            _ => {},
-        }
         return base
     }
 

src/ci/docker/linux-tested-targets/Dockerfile

@@ -34,6 +34,14 @@ ENV RUST_CONFIGURE_ARGS \
       --musl-root-x86_64=/musl-x86_64 \
       --musl-root-i686=/musl-i686
 
+# Newer binutils broke things on some vms/distros (i.e., linking against
+# unknown relocs disabled by the following flag), so we need to go out of our
+# way to produce "super compatible" binaries.
+#
+# See: https://github.com/rust-lang/rust/issues/34978
+ENV CFLAGS_i686_unknown_linux_gnu=-Wa,-mrelax-relocations=no \
+    CFLAGS_x86_64_unknown_linux_gnu=-Wa,-mrelax-relocations=no
+
 ENV SCRIPT \
       python2.7 ../x.py test \
           --target x86_64-unknown-linux-musl \

src/ci/docker/linux-tested-targets/build-musl.sh

@@ -11,7 +11,10 @@
 
 set -ex
 
-export CFLAGS="-fPIC"
+# We need to mitigate rust-lang/rust#34978 when compiling musl itself as well
+export CFLAGS="-fPIC -Wa,-mrelax-relocations=no"
+export CXXFLAGS="-Wa,-mrelax-relocations=no"
+
 MUSL=musl-1.1.14
 curl https://www.musl-libc.org/releases/$MUSL.tar.gz | tar xzf -
 cd $MUSL

src/doc/nomicon/src/phantom-data.md

@@ -82,5 +82,23 @@ standard library made a utility for itself called `Unique<T>` which:
 
 * wraps a `*const T` for variance
 * includes a `PhantomData<T>`
-* auto-derives Send/Sync as if T was contained
-* marks the pointer as NonZero for the null-pointer optimization
+* auto-derives `Send`/`Sync` as if T was contained
+* marks the pointer as `NonZero` for the null-pointer optimization
+
+## Table of `PhantomData` patterns
+
+Here’s a table of all the wonderful ways `PhantomData` could be used:
+
+| Phantom type                | `'a`      | `T`                       |
+|-----------------------------|-----------|---------------------------|
+| `PhantomData<T>`            | -         | variant (with drop check) |
+| `PhantomData<&'a T>`        | variant   | variant                   |
+| `PhantomData<&'a mut T>`    | variant   | invariant                 |
+| `PhantomData<*const T>`     | -         | variant                   |
+| `PhantomData<*mut T>`       | -         | invariant                 |
+| `PhantomData<fn(T)>`        | -         | contravariant (*)         |
+| `PhantomData<fn() -> T>`    | -         | variant                   |
+| `PhantomData<fn(T) -> T>`   | -         | invariant                 |
+| `PhantomData<Cell<&'a ()>>` | invariant | -                         |
+
+(*) If contravariance gets scrapped, this would be invariant.

src/libcompiler_builtins/build.rs

@@ -92,7 +92,15 @@ fn main() {
         // compiler-rt's build system already
         cfg.flag("-fno-builtin");
         cfg.flag("-fvisibility=hidden");
-        cfg.flag("-fomit-frame-pointer");
+        // Accepted practice on Solaris is to never omit frame pointer so that
+        // system observability tools work as expected.  In addition, at least
+        // on Solaris, -fomit-frame-pointer on sparcv9 appears to generate
+        // references to data outside of the current stack frame.  A search of
+        // the gcc bug database provides a variety of issues surrounding
+        // -fomit-frame-pointer on non-x86 platforms.
+        if !target.contains("solaris") && !target.contains("sparc") {
+            cfg.flag("-fomit-frame-pointer");
+        }
         cfg.flag("-ffreestanding");
         cfg.define("VISIBILITY_HIDDEN", None);
     }

src/liblibc

@@ -220,15 +220,24 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
                 // Note that `break` and `continue` statements
                 // may cause additional edges.
 
-                // Is the condition considered part of the loop?
                 let loopback = self.add_dummy_node(&[pred]);              // 1
-                let cond_exit = self.expr(&cond, loopback);             // 2
-                let expr_exit = self.add_ast_node(expr.id, &[cond_exit]); // 3
+
+                // Create expr_exit without pred (cond_exit)
+                let expr_exit = self.add_ast_node(expr.id, &[]);         // 3
+
+                // The LoopScope needs to be on the loop_scopes stack while evaluating the
+                // condition and the body of the loop (both can break out of the loop)
                 self.loop_scopes.push(LoopScope {
                     loop_id: expr.id,
                     continue_index: loopback,
                     break_index: expr_exit
                 });
+
+                let cond_exit = self.expr(&cond, loopback);             // 2
+
+                // Add pred (cond_exit) to expr_exit
+                self.add_contained_edge(cond_exit, expr_exit);
+
                 let body_exit = self.block(&body, cond_exit);          // 4
                 self.add_contained_edge(body_exit, loopback);            // 5
                 self.loop_scopes.pop();
@@ -294,17 +303,17 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
                 self.add_unreachable_node()
             }
 
-            hir::ExprBreak(label, ref opt_expr) => {
+            hir::ExprBreak(destination, ref opt_expr) => {
                 let v = self.opt_expr(opt_expr, pred);
-                let loop_scope = self.find_scope(expr, label);
+                let loop_scope = self.find_scope(expr, destination);
                 let b = self.add_ast_node(expr.id, &[v]);
                 self.add_exiting_edge(expr, b,
                                       loop_scope, loop_scope.break_index);
                 self.add_unreachable_node()
             }
 
-            hir::ExprAgain(label) => {
-                let loop_scope = self.find_scope(expr, label);
+            hir::ExprAgain(destination) => {
+                let loop_scope = self.find_scope(expr, destination);
                 let a = self.add_ast_node(expr.id, &[pred]);
                 self.add_exiting_edge(expr, a,
                                       loop_scope, loop_scope.continue_index);
@@ -579,17 +588,18 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
 
     fn find_scope(&self,
                   expr: &hir::Expr,
-                  label: Option<hir::Label>) -> LoopScope {
-        match label {
-            None => *self.loop_scopes.last().unwrap(),
-            Some(label) => {
+                  destination: hir::Destination) -> LoopScope {
+
+        match destination.loop_id.into() {
+            Ok(loop_id) => {
                 for l in &self.loop_scopes {
-                    if l.loop_id == label.loop_id {
+                    if l.loop_id == loop_id {
                         return *l;
                     }
                 }
-                span_bug!(expr.span, "no loop scope for id {}", label.loop_id);
+                span_bug!(expr.span, "no loop scope for id {}", loop_id);
             }
+            Err(err) => span_bug!(expr.span, "loop scope error: {}",  err)
         }
     }
 }