Auto merge of rust-lang#3593 - RalfJung:native-lib, r=RalfJung

rename 'extern-so' to 'native-lib'

Calling "extern" functions is not super clear IMO (extern to what), but saying that we are calling "native" functions from inside the interpreter makes it very clear I think.

src/tools/miri/.gitignore

@@ -9,5 +9,5 @@ tex/*/out
 perf.data
 perf.data.old
 flamegraph.svg
-tests/extern-so/libtestlib.so
+tests/native-lib/libtestlib.so
 .auto-*

src/tools/miri/README.md

@@ -374,17 +374,17 @@ to Miri failing to detect cases of undefined behavior in a program.
   this flag is **unsound**.
 * `-Zmiri-disable-weak-memory-emulation` disables the emulation of some C++11 weak
   memory effects.
-* `-Zmiri-extern-so-file=<path to a shared object file>` is an experimental flag for providing support
-  for FFI calls. Functions not provided by that file are still executed via the usual Miri shims.
-  **WARNING**: If an invalid/incorrect `.so` file is specified, this can cause undefined behaviour in Miri itself!
-  And of course, Miri cannot do any checks on the actions taken by the external code.
+* `-Zmiri-native-lib=<path to a shared object file>` is an experimental flag for providing support
+  for calling native functions from inside the interpreter via FFI. Functions not provided by that
+  file are still executed via the usual Miri shims.
+  **WARNING**: If an invalid/incorrect `.so` file is specified, this can cause Undefined Behavior in Miri itself!
+  And of course, Miri cannot do any checks on the actions taken by the native code.
   Note that Miri has its own handling of file descriptors, so if you want to replace *some* functions
   working on file descriptors, you will have to replace *all* of them, or the two kinds of
   file descriptors will be mixed up.
   This is **work in progress**; currently, only integer arguments and return values are
   supported (and no, pointer/integer casts to work around this limitation will not work;
-  they will fail horribly). It also only works on unix hosts for now.
-  Follow [the discussion on supporting other types](https://github.com/rust-lang/miri/issues/2365).
+  they will fail horribly). It also only works on Linux hosts for now.
 * `-Zmiri-measureme=<name>` enables `measureme` profiling for the interpreted program.
    This can be used to find which parts of your program are executing slowly under Miri.
    The profile is written out to a file inside a directory called `<name>`, and can be processed

src/tools/miri/src/bin/miri.rs

@@ -575,18 +575,15 @@ fn main() {
                 "full" => BacktraceStyle::Full,
                 _ => show_error!("-Zmiri-backtrace may only be 0, 1, or full"),
             };
-        } else if let Some(param) = arg.strip_prefix("-Zmiri-extern-so-file=") {
+        } else if let Some(param) = arg.strip_prefix("-Zmiri-native-lib=") {
             let filename = param.to_string();
             if std::path::Path::new(&filename).exists() {
-                if let Some(other_filename) = miri_config.external_so_file {
-                    show_error!(
-                        "-Zmiri-extern-so-file is already set to {}",
-                        other_filename.display()
-                    );
+                if let Some(other_filename) = miri_config.native_lib {
+                    show_error!("-Zmiri-native-lib is already set to {}", other_filename.display());
                 }
-                miri_config.external_so_file = Some(filename.into());
+                miri_config.native_lib = Some(filename.into());
             } else {
-                show_error!("-Zmiri-extern-so-file `{}` does not exist", filename);
+                show_error!("-Zmiri-native-lib `{}` does not exist", filename);
             }
         } else if let Some(param) = arg.strip_prefix("-Zmiri-num-cpus=") {
             let num_cpus = param

src/tools/miri/src/eval.rs

@@ -142,8 +142,8 @@ pub struct MiriConfig {
     /// Whether Stacked Borrows and Tree Borrows retagging should recurse into fields of datatypes.
     pub retag_fields: RetagFields,
     /// The location of a shared object file to load when calling external functions
-    /// FIXME! consider allowing users to specify paths to multiple SO files, or to a directory
-    pub external_so_file: Option<PathBuf>,
+    /// FIXME! consider allowing users to specify paths to multiple files, or to a directory
+    pub native_lib: Option<PathBuf>,
     /// Run a garbage collector for BorTags every N basic blocks.
     pub gc_interval: u32,
     /// The number of CPUs to be reported by miri.
@@ -188,7 +188,7 @@ impl Default for MiriConfig {
             preemption_rate: 0.01, // 1%
             report_progress: None,
             retag_fields: RetagFields::Yes,
-            external_so_file: None,
+            native_lib: None,
             gc_interval: 10_000,
             num_cpus: 1,
             page_size: None,

src/tools/miri/src/machine.rs

@@ -535,11 +535,11 @@ pub struct MiriMachine<'mir, 'tcx> {
     // The total number of blocks that have been executed.
     pub(crate) basic_block_count: u64,
 
-    /// Handle of the optional shared object file for external functions.
+    /// Handle of the optional shared object file for native functions.
     #[cfg(target_os = "linux")]
-    pub external_so_lib: Option<(libloading::Library, std::path::PathBuf)>,
+    pub native_lib: Option<(libloading::Library, std::path::PathBuf)>,
     #[cfg(not(target_os = "linux"))]
-    pub external_so_lib: Option<!>,
+    pub native_lib: Option<!>,
 
     /// Run a garbage collector for BorTags every N basic blocks.
     pub(crate) gc_interval: u32,
@@ -665,7 +665,7 @@ impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
             basic_block_count: 0,
             clock: Clock::new(config.isolated_op == IsolatedOp::Allow),
             #[cfg(target_os = "linux")]
-            external_so_lib: config.external_so_file.as_ref().map(|lib_file_path| {
+            native_lib: config.native_lib.as_ref().map(|lib_file_path| {
                 let target_triple = layout_cx.tcx.sess.opts.target_triple.triple();
                 // Check if host target == the session target.
                 if env!("TARGET") != target_triple {
@@ -687,7 +687,7 @@ impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
                 )
             }),
             #[cfg(not(target_os = "linux"))]
-            external_so_lib: config.external_so_file.as_ref().map(|_| {
+            native_lib: config.native_lib.as_ref().map(|_| {
                 panic!("loading external .so files is only supported on Linux")
             }),
             gc_interval: config.gc_interval,
@@ -802,7 +802,7 @@ impl VisitProvenance for MiriMachine<'_, '_> {
             preemption_rate: _,
             report_progress: _,
             basic_block_count: _,
-            external_so_lib: _,
+            native_lib: _,
             gc_interval: _,
             since_gc: _,
             num_cpus: _,