Merge pull request from GHSA-wh6w-3828-g9qf

* Unconditionally use `MemoryImageSlot`

This commit removes the internal branching within the pooling instance
allocator to sometimes use a `MemoryImageSlot` and sometimes now.
Instead this is now unconditionally used in all situations on all
platforms. This fixes an issue where the state of a slot could get
corrupted if modules being instantiated switched from having images to
not having an image or vice versa.

The bulk of this commit is the removal of the `memory-init-cow`
compile-time feature in addition to adding Windows support to the
`cow.rs` file.

* Fix compile on Unix

* Add a stricter assertion for static memory bounds

Double-check that when a memory is allocated the configuration required
is satisfied by the pooling allocator.

crates/wasmtime/Cargo.toml

@@ -62,7 +62,6 @@ default = [
   'parallel-compilation',
   'cranelift',
   'pooling-allocator',
-  'memory-init-cow',
   'vtune',
 ]
 
@@ -104,13 +103,6 @@ all-arch = ["wasmtime-cranelift?/all-arch"]
 # need portable signal handling.
 posix-signals-on-macos = ["wasmtime-runtime/posix-signals-on-macos"]
 
-# Enables, on supported platforms, the usage of copy-on-write initialization of
-# compatible linear memories. For more information see the documentation of
-# `Config::memory_init_cow`.
-#
-# Enabling this feature has no effect on unsupported platforms.
-memory-init-cow = ["wasmtime-runtime/memory-init-cow"]
-
 # Enables in-progress support for the component model. Note that this feature is
 # in-progress, buggy, and incomplete. This is primarily here for internal
 # testing purposes.

crates/wasmtime/src/config.rs

@@ -1340,8 +1340,6 @@ impl Config {
     ///
     /// [`Module::deserialize_file`]: crate::Module::deserialize_file
     /// [`Module`]: crate::Module
-    #[cfg(feature = "memory-init-cow")]
-    #[cfg_attr(nightlydoc, doc(cfg(feature = "memory-init-cow")))]
     pub fn memory_init_cow(&mut self, enable: bool) -> &mut Self {
         self.memory_init_cow = enable;
         self
@@ -1367,8 +1365,6 @@ impl Config {
     /// on.
     ///
     /// This option is disabled by default.
-    #[cfg(feature = "memory-init-cow")]
-    #[cfg_attr(nightlydoc, doc(cfg(feature = "memory-init-cow")))]
     pub fn force_memory_init_memfd(&mut self, enable: bool) -> &mut Self {
         self.force_memory_init_memfd = enable;
         self
@@ -1409,8 +1405,6 @@ impl Config {
     /// as the maximum module initial memory content size.
     ///
     /// By default this value is 16 MiB.
-    #[cfg(feature = "memory-init-cow")]
-    #[cfg_attr(nightlydoc, doc(cfg(feature = "memory-init-cow")))]
     pub fn memory_guaranteed_dense_image_size(&mut self, size_in_bytes: u64) -> &mut Self {
         self.memory_guaranteed_dense_image_size = size_in_bytes;
         self
@@ -1683,11 +1677,7 @@ impl PoolingAllocationConfig {
     /// Configures the method by which slots in the pooling allocator are
     /// allocated to instances
     ///
-    /// This defaults to [`PoolingAllocationStrategy::ReuseAffinity`] when the
-    /// `memory-init-cow` feature of Wasmtime is enabled, which is enabled by
-    /// default. Otherwise it defaults to
-    /// [`PoolingAllocationStrategy::NextAvailable`] Otherwise it defaults to
-    /// [`PoolingAllocationStrategy::NextAvailable`].
+    /// This defaults to [`PoolingAllocationStrategy::ReuseAffinity`] .
     pub fn strategy(&mut self, strategy: PoolingAllocationStrategy) -> &mut Self {
         self.config.strategy = strategy;
         self