Auto merge of #45002 - oli-obk:miri, r=<try>

Validate miri against the HIR const evaluator

r? @eddyb

cc @alexcrichton @arielb1 @RalfJung

The interesting parts are the last few functions in `librustc_const_eval/eval.rs`

* We warn if miri produces an error while HIR const eval does not.
* We warn if miri produces a value that does not match the value produced by HIR const eval
* if miri succeeds and HIR const eval fails, nothing is emitted, but we still return the HIR error
* if both error, nothing is emitted and the HIR const eval error is returned

So there are no actual changes, except that miri is forced to produce the same values as the old const eval.

* This does **not** touch the const evaluator in trans at all. That will come in a future PR.
* This does **not** cause any code to compile that didn't compile before. That will also come in the future

It would be great if someone could start a crater run if travis passes

.travis.yml

@@ -294,6 +294,7 @@ before_deploy:
           cp -r obj/build/dist/* deploy/$TRAVIS_COMMIT;
       fi
   - travis_retry gem update --system
+  - ls -la deploy/$TRAVIS_COMMIT
 
 deploy:
   - provider: s3

src/bootstrap/bin/rustc.rs

@@ -246,6 +246,9 @@ fn main() {
         // When running miri tests, we need to generate MIR for all libraries
         if env::var("TEST_MIRI").ok().map_or(false, |val| val == "true") {
             cmd.arg("-Zalways-encode-mir");
+            if stage != "0" {
+                cmd.arg("-Zmiri");
+            }
             cmd.arg("-Zmir-emit-validate=1");
         }
 

src/bootstrap/builder.rs

@@ -495,13 +495,11 @@ impl<'a> Builder<'a> {
         if let Some(target_linker) = self.build.linker(target) {
             cargo.env("RUSTC_TARGET_LINKER", target_linker);
         }
+        cargo.env("RUSTC_DEBUGINFO", self.config.rust_debuginfo.to_string())
+            .env("RUSTC_DEBUGINFO_LINES", self.config.rust_debuginfo_lines.to_string());
 
         if mode != Mode::Tool {
-            // Tools don't get debuginfo right now, e.g. cargo and rls don't
-            // get compiled with debuginfo.
-            cargo.env("RUSTC_DEBUGINFO", self.config.rust_debuginfo.to_string())
-                 .env("RUSTC_DEBUGINFO_LINES", self.config.rust_debuginfo_lines.to_string())
-                 .env("RUSTC_FORCE_UNSTABLE", "1");
+            cargo.env("RUSTC_FORCE_UNSTABLE", "1");
 
             // Currently the compiler depends on crates from crates.io, and
             // then other crates can depend on the compiler (e.g. proc-macro

src/bootstrap/check.rs

@@ -321,6 +321,7 @@ impl Step for Rustfmt {
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub struct Miri {
+    stage: u32,
     host: Interned<String>,
 }
 
@@ -336,15 +337,17 @@ impl Step for Miri {
 
     fn make_run(run: RunConfig) {
         run.builder.ensure(Miri {
+            stage: run.builder.top_stage,
             host: run.target,
         });
     }
 
     /// Runs `cargo test` for miri.
     fn run(self, builder: &Builder) {
         let build = builder.build;
+        let stage = self.stage;
         let host = self.host;
-        let compiler = builder.compiler(1, host);
+        let compiler = builder.compiler(stage, host);
 
         if let Some(miri) = builder.ensure(tool::Miri { compiler, target: self.host }) {
             let mut cargo = builder.cargo(compiler, Mode::Tool, host, "test");
@@ -766,6 +769,7 @@ impl Step for Compiletest {
         if build.config.rust_debuginfo_tests {
             flags.push("-g".to_string());
         }
+        flags.push("-Zmiri -Zunstable-options".to_string());
 
         if let Some(linker) = build.linker(target) {
             cmd.arg("--linker").arg(linker);

src/librustc/Cargo.toml

@@ -16,13 +16,17 @@ graphviz = { path = "../libgraphviz" }
 jobserver = "0.1"
 log = "0.3"
 owning_ref = "0.3.3"
+rustc_apfloat = { path = "../librustc_apfloat" }
 rustc_back = { path = "../librustc_back" }
 rustc_const_math = { path = "../librustc_const_math" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_errors = { path = "../librustc_errors" }
 serialize = { path = "../libserialize" }
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
+backtrace = "0.3.3"
+byteorder = { version = "1.1", features = ["i128"]}
+
 
 # Note that these dependencies are a lie, they're just here to get linkage to
 # work.

src/librustc/lib.rs

@@ -64,6 +64,7 @@
 #![feature(unboxed_closures)]
 #![feature(underscore_lifetimes)]
 #![feature(trace_macros)]
+#![feature(catch_expr)]
 #![feature(test)]
 
 #![recursion_limit="512"]
@@ -89,6 +90,10 @@ extern crate jobserver;
 
 extern crate serialize as rustc_serialize; // used by deriving
 
+extern crate rustc_apfloat;
+extern crate byteorder;
+extern crate backtrace;
+
 // Note that librustc doesn't actually depend on these crates, see the note in
 // `Cargo.toml` for this crate about why these are here.
 #[allow(unused_extern_crates)]