whitelist std::ptr::read

src/lib.rs

@@ -255,9 +255,26 @@ impl<'a, 'mir, 'tcx> Machine<'a, 'mir, 'tcx> for Evaluator<'tcx> {
 
     const STATIC_KIND: Option<MiriMemoryKind> = Some(MiriMemoryKind::MutStatic);
 
-    #[inline(always)]
     fn enforce_validity(ecx: &EvalContext<'a, 'mir, 'tcx, Self>) -> bool {
-        ecx.machine.validate
+        if !ecx.machine.validate {
+            return false;
+        }
+
+        // Some functions are whitelisted until we figure out how to fix them.
+        // We walk up the stack a few frames to also cover their callees.
+        const WHITELIST: &[&str] = &[
+            // Uses mem::uninitialized
+            "std::ptr::read",
+        ];
+        for frame in ecx.stack().iter()
+            .rev().take(3)
+        {
+            let name = frame.instance.to_string();
+            if WHITELIST.iter().any(|white| name.starts_with(white)) {
+                return false;
+            }
+        }
+        true
     }
 
     /// Returns Ok() when the function was handled, fail otherwise

tests/compiletest.rs

@@ -103,8 +103,6 @@ fn miri_pass(sysroot: &Path, path: &str, target: &str, host: &str, need_fullmir:
     flags.push("-Dwarnings -Dunused".to_owned()); // overwrite the -Aunused in compiletest-rs
     if have_fullmir() {
         flags.push("-Zmiri-start-fn".to_owned());
-        // start-fn uses ptr::read, and so fails validation
-        flags.push("-Zmiri-disable-validation".to_owned());
     }
     if opt {
         flags.push("-Zmir-opt-level=3".to_owned());

tests/run-pass/call_drop_through_owned_slice.rs

@@ -1,6 +1,3 @@
-// FIXME validation disabled because ptr::read uses mem::uninitialized
-// compile-flags: -Zmiri-disable-validation
-
 struct Bar;
 
 static mut DROP_COUNT: usize = 0;

tests/run-pass/issue-29746.rs

@@ -8,9 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// FIXME validation disabled because ptr::read uses mem::uninitialized
-// compile-flags: -Zmiri-disable-validation
-
 // zip!(a1,a2,a3,a4) is equivalent to:
 //  a1.zip(a2).zip(a3).zip(a4).map(|(((x1,x2),x3),x4)| (x1,x2,x3,x4))
 macro_rules! zip {

tests/run-pass/sendable-class.rs

@@ -8,9 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// FIXME validation disabled because ptr::read uses mem::uninitialized
-// compile-flags: -Zmiri-disable-validation
-
 // Test that a class with only sendable fields can be sent
 
 use std::sync::mpsc::channel;

tests/run-pass/unique-send.rs

@@ -8,9 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// FIXME validation disabled because ptr::read uses mem::uninitialized
-// compile-flags: -Zmiri-disable-validation
-
 #![feature(box_syntax)]
 
 use std::sync::mpsc::channel;