add pointers being returned from C, add test_return_ptr

Author: Strophox

src/tools/miri/src/shims/native_lib.rs

@@ -3,8 +3,11 @@ use std::ops::Deref;
 
 use libffi::high::call as ffi;
 use libffi::low::CodePtr;
-use rustc_abi::{BackendRepr, HasDataLayout};
-use rustc_middle::ty::{self as ty, IntTy, UintTy};
+use rustc_abi::{BackendRepr, HasDataLayout, Size};
+use rustc_middle::{
+    mir::interpret::Pointer,
+    ty::{self as ty, IntTy, UintTy},
+};
 use rustc_span::Symbol;
 
 use crate::*;
@@ -75,6 +78,11 @@ trait EvalContextExtPriv<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 unsafe { ffi::call::<()>(ptr, libffi_args.as_slice()) };
                 return interp_ok(ImmTy::uninit(dest.layout));
             }
+            ty::RawPtr(..) => {
+                let x = unsafe { ffi::call::<*const ()>(ptr, libffi_args.as_slice()) };
+                let ptr = Pointer::new(Provenance::Wildcard, Size::from_bytes(x.addr()));
+                Scalar::from_pointer(ptr, this)
+            }
             _ => throw_unsup_format!("unsupported return type for native call: {:?}", link_name),
         };
         interp_ok(ImmTy::from_scalar(scalar, dest.layout))

src/tools/miri/tests/native-lib/pass/ptr_write_access.rs

@@ -21,6 +21,7 @@ fn main() {
     test_overwrite_dangling();
     test_pass_dangling();
     test_swap_ptr_triple_dangling();
+    test_return_ptr();
 }
 
 /// Test function that modifies an int.
@@ -207,7 +208,6 @@ fn test_swap_ptr_triple_dangling() {
 }
 
 
-/* TODO: Fix "unsupported return type"
 /// Test function that directly returns its pointer argument.
 fn test_return_ptr() {
     extern "C" {
@@ -220,4 +220,3 @@ fn test_return_ptr() {
     let ptr = unsafe { return_ptr(ptr) };
     assert_eq!(unsafe { *ptr }, x);
 }
-*/

src/tools/miri/tests/native-lib/ptr_write_access.c

@@ -23,6 +23,22 @@ EXPORT void init_array(int *array, size_t len, int val) {
   }
 }
 
+/* Test: test_init_static_inner */
+
+typedef struct SyncPtr {
+    int *ptr;
+} SyncPtr;
+
+EXPORT void init_static_inner(const SyncPtr *s_ptr, int val) {
+  *(s_ptr->ptr) = val;
+}
+
+/* Tests: test_exposed, test_pass_dangling */
+
+EXPORT void ignore_ptr(__attribute__((unused)) const int *ptr) {
+  return;
+}
+
 /* Test: test_expose_int */
 EXPORT void expose_int(const int *int_ptr, const int **pptr) {
   *pptr = int_ptr;
@@ -49,28 +65,12 @@ EXPORT void swap_ptr_tuple(Tuple *t_ptr) {
   t_ptr->ptr1 = tmp;
 }
 
-/* Test: test_init_static_inner */
-
-typedef struct SyncPtr {
-    int *ptr;
-} SyncPtr;
-
-EXPORT void init_static_inner(const SyncPtr *s_ptr, int val) {
-  *(s_ptr->ptr) = val;
-}
-
 /* Test: test_overwrite_dangling */
 
 EXPORT void overwrite_ptr(const int **pptr) {
   *pptr = NULL;
 }
 
-/* Test: test_pass_dangling */
-
-EXPORT void ignore_ptr(__attribute__((unused)) const int *ptr) {
-  return;
-}
-
 /* Test: test_swap_ptr_triple_dangling */
 
 typedef struct Triple {