Remove virtual memory support (#408)

* remove support for virtual memory in wasmi_core and wasmi

* remove virtual memory support for GitHub Actions CI

* rename buffer_vec.rs -> byte_buffer.rs

* use windows-latest in CI instead of windows-2019

We were required to use windows-2019 because of the virtual memory feature which is removed now.

.github/workflows/rust.yml

@@ -49,21 +49,9 @@ jobs:
       matrix:
         # windows-latest was pinned to windows-2019
         # because of https://github.com/paritytech/wasmi/runs/5021520759
-        os: [ubuntu-latest, windows-2019, macos-latest]
-        include:
-          # Include a new variable `rustc-args` with `-- --test-threads 1`
-          # for windows-2019 to be used with virtual_memory crate feature
-          # enabled while testing.
-          - os: windows-2019
-            test-args: "--test-threads 1"
+        os: [ubuntu-latest, windows-latest, macos-latest]
     runs-on: ${{ matrix.os }}
     steps:
-      - name: Configure Pagefile for Windows
-        if: matrix.os == 'windows-2019'
-        uses: al-cheb/[email protected]
-        with:
-          minimum-size: 6GB
-          maximum-size: 32GB
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
         with:
@@ -83,10 +71,9 @@ jobs:
         uses: actions-rs/cargo@v1
         env:
           RUSTFLAGS: '--cfg debug_assertions'
-          TEST_FLAGS: ${{ matrix.test-args }}
         with:
           command: test
-          args: --workspace --release --all-features -- $TEST_FLAGS
+          args: --workspace --release --all-features
 
   fmt:
     name: Formatting

core/Cargo.toml

@@ -15,7 +15,6 @@ memory_units = "0.4.0"
 libm = "0.2.1"
 num-rational = { version = "0.4", default-features = false, features = ["num-bigint"] }
 num-traits = { version = "0.2.8", default-features = false }
-region = { version = "3.0", optional = true }
 downcast-rs = { version = "1.2", default-features = false }
 
 [dev-dependencies]
@@ -30,13 +29,3 @@ std = [
     "num-traits/std",
     "downcast-rs/std",
 ]
-# Enables OS supported virtual memory.
-#
-# Note
-#
-# - This feature is only supported on 64-bit platforms.
-#   For 32-bit platforms the linear memory will fallback to using the Vec
-#   based implementation.
-# - The default is to fall back is an inefficient vector based implementation.
-# - By nature this feature requires `region` and the Rust standard library.
-virtual_memory = ["region", "std"]

core/src/lib.rs

@@ -7,18 +7,12 @@ mod trap;
 mod untyped;
 mod value;
 
-#[cfg(feature = "virtual_memory")]
-mod vmem;
-
 #[cfg(not(feature = "std"))]
 extern crate alloc;
 
 #[cfg(feature = "std")]
 extern crate std as alloc;
 
-#[cfg(feature = "virtual_memory")]
-pub use self::vmem::{VirtualMemory, VirtualMemoryError};
-
 /// WebAssembly-specific sizes and units.
 pub mod memory_units {
     pub use memory_units::{size_of, wasm32::*, ByteSize, Bytes, RoundUpTo};

wasmi_v1/Cargo.toml

@@ -31,16 +31,6 @@ std = [
     "wasmparser/std",
     "spin/std",
 ]
-# Enables OS supported virtual memory.
-#
-# Note
-#
-# - This feature is only supported on 64-bit platforms.
-#   For 32-bit platforms the linear memory will fallback to using the Vec
-#   based implementation.
-# - The default is to fall back is an inefficient vector based implementation.
-# - By nature this feature requires `region` and the Rust standard library.
-virtual_memory = ["wasmi_core/virtual_memory", "std"]
 
 [[bench]]
 name = "benches"

wasmi_v1/src/memory/buffer_vec.rs → wasmi_v1/src/memory/byte_buffer.rs

@@ -1,16 +1,5 @@
 use super::{max_memory_len, MemoryError};
 use alloc::{vec, vec::Vec};
-use core::{fmt, fmt::Display};
-
-/// Dummy error for fallible `Vec`-based virtual memory operations.
-#[derive(Debug)]
-pub struct VirtualMemoryError {}
-
-impl Display for VirtualMemoryError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "encountered failure while operating with virtual memory")
-    }
-}
 
 /// A `Vec`-based byte buffer implementation.
 ///

wasmi_v1/src/memory/mod.rs

@@ -1,12 +1,6 @@
-#[cfg(all(feature = "virtual_memory", target_pointer_width = "64"))]
-#[path = "buffer_vmem.rs"]
 mod byte_buffer;
 
-#[cfg(not(all(feature = "virtual_memory", target_pointer_width = "64")))]
-#[path = "buffer_vec.rs"]
-mod byte_buffer;
-
-use self::byte_buffer::{ByteBuffer, VirtualMemoryError};
+use self::byte_buffer::ByteBuffer;
 use super::{AsContext, AsContextMut, Index, StoreContext, StoreContextMut, Stored};
 use core::{fmt, fmt::Display};
 use wasmi_core::memory_units::{Bytes, Pages};
@@ -38,8 +32,6 @@ pub enum MemoryError {
     OutOfBoundsGrowth,
     /// Tried to access linear memory out of bounds.
     OutOfBoundsAccess,
-    /// A generic virtual memory error.
-    Vmem(byte_buffer::VirtualMemoryError),
     /// Occurs when a memory type does not satisfy the constraints of another.
     UnsatisfyingMemoryType {
         /// The unsatisfying [`MemoryType`].
@@ -52,16 +44,15 @@ pub enum MemoryError {
 impl Display for MemoryError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
-            MemoryError::OutOfBoundsAllocation => {
+            Self::OutOfBoundsAllocation => {
                 write!(f, "tried to allocate too much virtual memory")
             }
-            MemoryError::OutOfBoundsGrowth => {
+            Self::OutOfBoundsGrowth => {
                 write!(f, "tried to grow virtual memory out of bounds")
             }
-            MemoryError::OutOfBoundsAccess => {
+            Self::OutOfBoundsAccess => {
                 write!(f, "tried to access virtual memory out of bounds")
             }
-            MemoryError::Vmem(error) => Display::fmt(error, f),
             Self::UnsatisfyingMemoryType {
                 unsatisfying,
                 required,
@@ -76,12 +67,6 @@ impl Display for MemoryError {
     }
 }
 
-impl From<VirtualMemoryError> for MemoryError {
-    fn from(error: VirtualMemoryError) -> Self {
-        Self::Vmem(error)
-    }
-}
-
 /// Returns the maximum virtual memory buffer length in bytes.
 fn max_memory_len() -> usize {
     i32::MAX as u32 as usize