Get rid of env var race condition once and for all

Author: oli-obk

Cargo.lock

@@ -19,7 +19,11 @@ use rustc::ty::TyCtxt;
 use syntax::ast::{self, MetaItemKind, NestedMetaItemKind};
 use std::path::PathBuf;
 
-struct MiriCompilerCalls(RustcDefaultCalls);
+struct MiriCompilerCalls {
+    default: RustcDefaultCalls,
+    /// whether we are building for the host
+    host_target: bool,
+}
 
 impl<'a> CompilerCalls<'a> for MiriCompilerCalls {
     fn early_callback(
@@ -30,7 +34,7 @@ impl<'a> CompilerCalls<'a> for MiriCompilerCalls {
         descriptions: &rustc_errors::registry::Registry,
         output: ErrorOutputType,
     ) -> Compilation {
-        self.0.early_callback(
+        self.default.early_callback(
             matches,
             sopts,
             cfg,
@@ -47,7 +51,7 @@ impl<'a> CompilerCalls<'a> for MiriCompilerCalls {
         ofile: &Option<PathBuf>,
         descriptions: &rustc_errors::registry::Registry,
     ) -> Option<(Input, Option<PathBuf>)> {
-        self.0.no_input(
+        self.default.no_input(
             matches,
             sopts,
             cfg,
@@ -64,17 +68,17 @@ impl<'a> CompilerCalls<'a> for MiriCompilerCalls {
         odir: &Option<PathBuf>,
         ofile: &Option<PathBuf>,
     ) -> Compilation {
-        self.0.late_callback(matches, sess, input, odir, ofile)
+        self.default.late_callback(matches, sess, input, odir, ofile)
     }
     fn build_controller(
         &mut self,
         sess: &Session,
         matches: &getopts::Matches,
     ) -> CompileController<'a> {
-        let mut control = self.0.build_controller(sess, matches);
+        let mut control = self.default.build_controller(sess, matches);
         control.after_hir_lowering.callback = Box::new(after_hir_lowering);
         control.after_analysis.callback = Box::new(after_analysis);
-        if std::env::var("MIRI_HOST_TARGET") != Ok("yes".to_owned()) {
+        if !self.host_target {
             // only fully compile targets on the host
             control.after_analysis.stop = Compilation::Stop;
         }
@@ -254,6 +258,16 @@ fn main() {
 
     // for auxilary builds in unit tests
     args.push("-Zalways-encode-mir".to_owned());
+    let mut host_target = false;
+    args.retain(|arg| if arg == "--miri_host_target" {
+        host_target = true;
+        false // remove the flag, rustc doesn't know it
+    } else {
+        true
+    });
 
-    rustc_driver::run_compiler(&args, &mut MiriCompilerCalls(RustcDefaultCalls), None, None);
+    rustc_driver::run_compiler(&args, &mut MiriCompilerCalls {
+        default: RustcDefaultCalls,
+        host_target,
+    }, None, None);
 }

miri/bin/miri.rs

@@ -20,7 +20,11 @@ use rustc::hir::{self, itemlikevisit};
 use rustc::ty::TyCtxt;
 use syntax::ast;
 
-struct MiriCompilerCalls(RustcDefaultCalls);
+struct MiriCompilerCalls {
+    default: RustcDefaultCalls,
+    /// whether we are building for the host
+    host_target: bool,
+}
 
 impl<'a> CompilerCalls<'a> for MiriCompilerCalls {
     fn early_callback(
@@ -31,7 +35,7 @@ impl<'a> CompilerCalls<'a> for MiriCompilerCalls {
         descriptions: &rustc_errors::registry::Registry,
         output: ErrorOutputType
     ) -> Compilation {
-        self.0.early_callback(matches, sopts, cfg, descriptions, output)
+        self.default.early_callback(matches, sopts, cfg, descriptions, output)
     }
     fn no_input(
         &mut self,
@@ -42,7 +46,7 @@ impl<'a> CompilerCalls<'a> for MiriCompilerCalls {
         ofile: &Option<PathBuf>,
         descriptions: &rustc_errors::registry::Registry
     ) -> Option<(Input, Option<PathBuf>)> {
-        self.0.no_input(matches, sopts, cfg, odir, ofile, descriptions)
+        self.default.no_input(matches, sopts, cfg, odir, ofile, descriptions)
     }
     fn late_callback(
         &mut self,
@@ -52,13 +56,13 @@ impl<'a> CompilerCalls<'a> for MiriCompilerCalls {
         odir: &Option<PathBuf>,
         ofile: &Option<PathBuf>
     ) -> Compilation {
-        self.0.late_callback(matches, sess, input, odir, ofile)
+        self.default.late_callback(matches, sess, input, odir, ofile)
     }
     fn build_controller(&mut self, sess: &Session, matches: &getopts::Matches) -> CompileController<'a> {
-        let mut control = self.0.build_controller(sess, matches);
+        let mut control = self.default.build_controller(sess, matches);
         control.after_hir_lowering.callback = Box::new(after_hir_lowering);
         control.after_analysis.callback = Box::new(after_analysis);
-        if std::env::var("MIRI_HOST_TARGET") != Ok("yes".to_owned()) {
+        if !self.host_target {
             // only fully compile targets on the host
             control.after_analysis.stop = Compilation::Stop;
         }
@@ -139,7 +143,15 @@ fn main() {
         }
         let stderr = std::io::stderr();
         write!(stderr.lock(), "test [miri-pass] {} ... ", path.display()).unwrap();
-        let mut args: Vec<String> = std::env::args().collect();
+        let mut host_target = false;
+        let mut args: Vec<String> = std::env::args().filter(|arg| {
+            if arg == "--miri_host_target" {
+                host_target = true;
+                false // remove the flag, rustc doesn't know it
+            } else {
+                true
+            }
+        }).collect();
         // file to process
         args.push(path.display().to_string());
 

rustc_tests/src/main.rs

@@ -126,15 +126,14 @@ fn miri_pass(path: &str, target: &str, host: &str, fullmir: bool, opt: bool) {
         // For now, only validate without optimizations.  Inlining breaks validation.
         flags.push("-Zmir-emit-validate=1".to_owned());
     }
+    if target == host {
+        flags.push("--miri_host_target".to_owned());
+    }
     config.target_rustcflags = Some(flags.join(" "));
     // don't actually execute the final binary, it might be for other targets and we only care
     // about running miri, not the binary.
     config.runtool = Some("echo \"\" || ".to_owned());
-    if target == host {
-        std::env::set_var("MIRI_HOST_TARGET", "yes");
-    }
     compiletest::run_tests(&config);
-    std::env::set_var("MIRI_HOST_TARGET", "");
 }
 
 fn is_target_dir<P: Into<PathBuf>>(path: P) -> bool {