Make sure vmoffset are aligned to pointer size (for #4059)

lib/types/src/serialize.rs

@@ -211,7 +211,7 @@ pub struct MetadataHeader {
 impl MetadataHeader {
     /// Current ABI version. Increment this any time breaking changes are made
     /// to the format of the serialized data.
-    pub const CURRENT_VERSION: u32 = 4;
+    pub const CURRENT_VERSION: u32 = 5;
 
     /// Magic number to identify wasmer metadata.
     const MAGIC: [u8; 8] = *b"WASMER\0\0";

lib/types/src/vmoffsets.rs

@@ -12,6 +12,7 @@ use crate::{
 };
 use more_asserts::assert_lt;
 use std::convert::TryFrom;
+use std::mem::size_of;
 
 /// An index type for builtin functions.
 #[derive(Copy, Clone, Debug)]
@@ -284,34 +285,44 @@ impl VMOffsets {
             base.checked_add(num_items.checked_mul(item_size).unwrap())
                 .unwrap()
         }
+        /// Offset base by num_items items of size item_size, panicking on overflow
+        /// Also, will align the value on pointer size boundary,
+        /// to avoid misalignement issue
+        fn offset_by_aligned(base: u32, num_items: u32, item_size: u32) -> u32 {
+            align(
+                base.checked_add(num_items.checked_mul(item_size).unwrap())
+                    .unwrap(),
+                size_of::<&u32>() as u32,
+            )
+        }
 
         self.vmctx_signature_ids_begin = 0;
-        self.vmctx_imported_functions_begin = offset_by(
+        self.vmctx_imported_functions_begin = offset_by_aligned(
             self.vmctx_signature_ids_begin,
             self.num_signature_ids,
             u32::from(self.size_of_vmshared_signature_index()),
         );
-        self.vmctx_imported_tables_begin = offset_by(
+        self.vmctx_imported_tables_begin = offset_by_aligned(
             self.vmctx_imported_functions_begin,
             self.num_imported_functions,
             u32::from(self.size_of_vmfunction_import()),
         );
-        self.vmctx_imported_memories_begin = offset_by(
+        self.vmctx_imported_memories_begin = offset_by_aligned(
             self.vmctx_imported_tables_begin,
             self.num_imported_tables,
             u32::from(self.size_of_vmtable_import()),
         );
-        self.vmctx_imported_globals_begin = offset_by(
+        self.vmctx_imported_globals_begin = offset_by_aligned(
             self.vmctx_imported_memories_begin,
             self.num_imported_memories,
             u32::from(self.size_of_vmmemory_import()),
         );
-        self.vmctx_tables_begin = offset_by(
+        self.vmctx_tables_begin = offset_by_aligned(
             self.vmctx_imported_globals_begin,
             self.num_imported_globals,
             u32::from(self.size_of_vmglobal_import()),
         );
-        self.vmctx_memories_begin = offset_by(
+        self.vmctx_memories_begin = offset_by_aligned(
             self.vmctx_tables_begin,
             self.num_local_tables,
             u32::from(self.size_of_vmtable_definition()),