Auto merge of #814 - RalfJung:shims, r=RalfJung

move find_fn (which is not specific to foreign items) out of foreign_item

src/lib.rs

@@ -28,6 +28,7 @@ pub use rustc_mir::interpret::*;
 // Resolve ambiguity.
 pub use rustc_mir::interpret::{self, AllocMap, PlaceTy};
 
+pub use crate::shims::{EvalContextExt as ShimsEvalContextExt};
 pub use crate::shims::foreign_items::EvalContextExt as ForeignItemsEvalContextExt;
 pub use crate::shims::intrinsics::EvalContextExt as IntrinsicsEvalContextExt;
 pub use crate::operator::EvalContextExt as OperatorEvalContextExt;

src/shims/foreign_items.rs

@@ -1,4 +1,3 @@
-use rustc::ty;
 use rustc::ty::layout::{Align, LayoutOf, Size};
 use rustc::hir::def_id::DefId;
 use rustc::mir;
@@ -11,46 +10,6 @@ use crate::*;
 
 impl<'mir, 'tcx> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
-    fn find_fn(
-        &mut self,
-        instance: ty::Instance<'tcx>,
-        args: &[OpTy<'tcx, Tag>],
-        dest: Option<PlaceTy<'tcx, Tag>>,
-        ret: Option<mir::BasicBlock>,
-    ) -> InterpResult<'tcx, Option<&'mir mir::Body<'tcx>>> {
-        let this = self.eval_context_mut();
-        trace!("eval_fn_call: {:#?}, {:?}", instance, dest.map(|place| *place));
-
-        // First, run the common hooks also supported by CTFE.
-        if this.hook_fn(instance, args, dest)? {
-            this.goto_block(ret)?;
-            return Ok(None);
-        }
-        // There are some more lang items we want to hook that CTFE does not hook (yet).
-        if this.tcx.lang_items().align_offset_fn() == Some(instance.def.def_id()) {
-            // FIXME: return a real value in case the target allocation has an
-            // alignment bigger than the one requested.
-            let n = u128::max_value();
-            let dest = dest.unwrap();
-            let n = this.truncate(n, dest.layout);
-            this.write_scalar(Scalar::from_uint(n, dest.layout.size), dest)?;
-            this.goto_block(ret)?;
-            return Ok(None);
-        }
-
-        // Try to see if we can do something about foreign items.
-        if this.tcx.is_foreign_item(instance.def_id()) {
-            // An external function that we cannot find MIR for, but we can still run enough
-            // of them to make miri viable.
-            this.emulate_foreign_item(instance.def_id(), args, dest, ret)?;
-            // `goto_block` already handled.
-            return Ok(None);
-        }
-
-        // Otherwise, load the MIR.
-        Ok(Some(this.load_mir(instance.def)?))
-    }
-
     /// Returns the minimum alignment for the target architecture.
     fn min_align(&self) -> Align {
         let this = self.eval_context_ref();

src/shims/mod.rs

@@ -1,2 +1,49 @@
 pub mod foreign_items;
 pub mod intrinsics;
+
+use rustc::{ty, mir};
+
+use crate::*;
+
+impl<'mir, 'tcx> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
+    fn find_fn(
+        &mut self,
+        instance: ty::Instance<'tcx>,
+        args: &[OpTy<'tcx, Tag>],
+        dest: Option<PlaceTy<'tcx, Tag>>,
+        ret: Option<mir::BasicBlock>,
+    ) -> InterpResult<'tcx, Option<&'mir mir::Body<'tcx>>> {
+        let this = self.eval_context_mut();
+        trace!("eval_fn_call: {:#?}, {:?}", instance, dest.map(|place| *place));
+
+        // First, run the common hooks also supported by CTFE.
+        if this.hook_fn(instance, args, dest)? {
+            this.goto_block(ret)?;
+            return Ok(None);
+        }
+        // There are some more lang items we want to hook that CTFE does not hook (yet).
+        if this.tcx.lang_items().align_offset_fn() == Some(instance.def.def_id()) {
+            // FIXME: return a real value in case the target allocation has an
+            // alignment bigger than the one requested.
+            let n = u128::max_value();
+            let dest = dest.unwrap();
+            let n = this.truncate(n, dest.layout);
+            this.write_scalar(Scalar::from_uint(n, dest.layout.size), dest)?;
+            this.goto_block(ret)?;
+            return Ok(None);
+        }
+
+        // Try to see if we can do something about foreign items.
+        if this.tcx.is_foreign_item(instance.def_id()) {
+            // An external function that we cannot find MIR for, but we can still run enough
+            // of them to make miri viable.
+            this.emulate_foreign_item(instance.def_id(), args, dest, ret)?;
+            // `goto_block` already handled.
+            return Ok(None);
+        }
+
+        // Otherwise, load the MIR.
+        Ok(Some(this.load_mir(instance.def)?))
+    }
+}