Check pointer size and emit opaque type if required (#2637)

* Check size of pointer types

* Test that `__ptr32` is emitted as `u32`

* Update CHANGELOG.md

* Add expectation with raw pointer for clang 5

* Add expectation with raw pointer for clang 9

* Remove extra line

Author: pvdrz

CHANGELOG.md

@@ -184,6 +184,8 @@
 ## Removed
 ## Fixed
 - Allow compiling `bindgen-cli` with a static libclang.
+- Emit an opaque integer type for pointer types that don't have the same size
+  as the target's pointer size.
 ## Security
 
 # 0.68.1

bindgen-tests/tests/expectations/tests/libclang-5/ptr32-has-different-size.rs

@@ -0,0 +1,4 @@
+// bindgen-flags: -- -fms-extensions
+typedef struct TEST_STRUCT {
+  void* __ptr32 ptr_32bit;
+} TEST;

bindgen-tests/tests/expectations/tests/libclang-9/ptr32-has-different-size.rs

@@ -14,25 +14,36 @@ pub(crate) enum Error {
 
     /// Function ABI is not supported.
     UnsupportedAbi(&'static str),
+
+    /// The pointer type size does not match the target's pointer size.
+    InvalidPointerSize {
+        ty_name: String,
+        ty_size: usize,
+        ptr_size: usize,
+    },
 }
 
 impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.write_str(match *self {
+        match self {
             Error::NoLayoutForOpaqueBlob => {
-                "Tried to generate an opaque blob, but had no layout."
+                "Tried to generate an opaque blob, but had no layout.".fmt(f)
             }
             Error::InstantiationOfOpaqueType => {
                 "Instantiation of opaque template type or partial template specialization."
+                    .fmt(f)
             }
             Error::UnsupportedAbi(abi) => {
-                return write!(
+                 write!(
                     f,
                     "{} ABI is not supported by the configured Rust target.",
                     abi
                 )
             }
-        })
+            Error::InvalidPointerSize { ty_name, ty_size, ptr_size } => {
+                write!(f, "The {} pointer type has size {} but the current target's pointer size is {}.", ty_name, ty_size, ptr_size)
+            }
+        }
     }
 }
 

bindgen-tests/tests/expectations/tests/ptr32-has-different-size.rs

@@ -21,6 +21,7 @@ use self::struct_layout::StructLayoutTracker;
 use super::BindgenOptions;
 
 use crate::callbacks::{DeriveInfo, FieldInfo, TypeKind as DeriveTypeKind};
+use crate::codegen::error::Error;
 use crate::ir::analysis::{HasVtable, Sizedness};
 use crate::ir::annotations::{
     Annotations, FieldAccessorKind, FieldVisibilityKind,
@@ -3923,6 +3924,16 @@ impl TryToRustTy for Type {
             }
             TypeKind::Opaque => self.try_to_opaque(ctx, item),
             TypeKind::Pointer(inner) | TypeKind::Reference(inner) => {
+                // Check that this type has the same size as the target's pointer type.
+                let size = self.get_layout(ctx, item).size;
+                if size != ctx.target_pointer_size() {
+                    return Err(Error::InvalidPointerSize {
+                        ty_name: self.name().unwrap_or("unknown").into(),
+                        ty_size: size,
+                        ptr_size: ctx.target_pointer_size(),
+                    });
+                }
+
                 let is_const = ctx.resolve_type(inner).is_const();
 
                 let inner =