Optimize some functions in the wiggle crate (#5566)

* wiggle: Inline some trivial functions

This commit marks a number of functions in wiggle as `#[inline]` as
they're otherwise trivial, mostly returning constants. This comes out of
some work I looked at recently with Andrew where some of these functions
showed up in profiles when they shouldn't.

* wiggle: Optimize the `GuestMemory` for shared memory

This commit implements a minor optimization to the `GuestMemory`
implementation for Wasmtime to skip most methods if a shared memory is
in play. Shared memories never get borrowed and this can be used to
internally skip some borrow-checker methods.

* wiggle: Optimize `GuestPtr::to_vec`

This commit replaces the safe implementation of `GuestPtr::to_vec` with
an unsafe implementation. The purpose of this is to speed up the
function when used with shared memory which otherwise performs a bunch
of atomic reads for types like `u8` which does validation-per-element
and isn't vectorizable. On a benchmark I was helping Andrew with this
sped up the host code enough to the point that guest code dwarfed the
execution time.

* Fix build

crates/wiggle/generate/src/types/flags.rs

@@ -42,6 +42,7 @@ pub(super) fn define_flags(
 
         impl TryFrom<#repr> for #ident {
             type Error = wiggle::GuestError;
+            #[inline]
             fn try_from(value: #repr) -> Result<Self, wiggle::GuestError> {
                 if #repr::from(!#ident::all()) & value != 0 {
                     Err(wiggle::GuestError::InvalidFlagValue(stringify!(#ident)))
@@ -53,22 +54,26 @@ pub(super) fn define_flags(
 
         impl TryFrom<#abi_repr> for #ident {
             type Error = wiggle::GuestError;
+            #[inline]
             fn try_from(value: #abi_repr) -> Result<Self, wiggle::GuestError> {
                 #ident::try_from(#repr::try_from(value)?)
             }
         }
 
         impl From<#ident> for #repr {
+            #[inline]
             fn from(e: #ident) -> #repr {
                 e.bits
             }
         }
 
         impl<'a> wiggle::GuestType<'a> for #ident {
+            #[inline]
             fn guest_size() -> u32 {
                 #repr::guest_size()
             }
 
+            #[inline]
             fn guest_align() -> usize {
                 #repr::guest_align()
             }

crates/wiggle/generate/src/types/handle.rs

@@ -14,29 +14,34 @@ pub(super) fn define_handle(name: &witx::Id, h: &witx::HandleDatatype) -> TokenS
         pub struct #ident(u32);
 
         impl #ident {
+            #[inline]
             pub unsafe fn inner(&self) -> u32 {
                 self.0
             }
         }
 
         impl From<#ident> for u32 {
+            #[inline]
             fn from(e: #ident) -> u32 {
                 e.0
             }
         }
 
         impl From<#ident> for i32 {
+            #[inline]
             fn from(e: #ident) -> i32 {
                 e.0 as i32
             }
         }
 
         impl From<u32> for #ident {
+            #[inline]
             fn from(e: u32) -> #ident {
                 #ident(e)
             }
         }
         impl From<i32> for #ident {
+            #[inline]
             fn from(e: i32) -> #ident {
                 #ident(e as u32)
             }
@@ -49,18 +54,22 @@ pub(super) fn define_handle(name: &witx::Id, h: &witx::HandleDatatype) -> TokenS
         }
 
         impl<'a> wiggle::GuestType<'a> for #ident {
+            #[inline]
             fn guest_size() -> u32 {
                 #size
             }
 
+            #[inline]
             fn guest_align() -> usize {
                 #align
             }
 
+            #[inline]
             fn read(location: &wiggle::GuestPtr<'a, #ident>) -> Result<#ident, wiggle::GuestError> {
                 Ok(#ident(u32::read(&location.cast())?))
             }
 
+            #[inline]
             fn write(location: &wiggle::GuestPtr<'_, Self>, val: Self) -> Result<(), wiggle::GuestError> {
                 u32::write(&location.cast(), val.0)
             }

crates/wiggle/generate/src/types/record.rs

@@ -87,10 +87,12 @@ pub(super) fn define_struct(name: &witx::Id, s: &witx::RecordDatatype) -> TokenS
         }
 
         impl<'a> wiggle::GuestType<'a> for #ident #struct_lifetime {
+            #[inline]
             fn guest_size() -> u32 {
                 #size
             }
 
+            #[inline]
             fn guest_align() -> usize {
                 #align
             }

crates/wiggle/generate/src/types/variant.rs

@@ -80,6 +80,7 @@ pub(super) fn define_variant(
         quote! {
             impl TryFrom<#tag_ty> for #ident {
                 type Error = wiggle::GuestError;
+                #[inline]
                 fn try_from(value: #tag_ty) -> Result<#ident, wiggle::GuestError> {
                     match value {
                         #(#tryfrom_repr_cases),*,
@@ -90,6 +91,7 @@ pub(super) fn define_variant(
 
             impl TryFrom<#abi_ty> for #ident {
                 type Error = wiggle::GuestError;
+                #[inline]
                 fn try_from(value: #abi_ty) -> Result<#ident, wiggle::GuestError> {
                     #ident::try_from(#tag_ty::try_from(value)?)
                 }
@@ -107,6 +109,7 @@ pub(super) fn define_variant(
         });
         quote! {
             impl From<#ident> for #tag_ty {
+                #[inline]
                 fn from(v: #ident) -> #tag_ty {
                     match v {
                         #(#from_repr_cases),*,
@@ -148,10 +151,12 @@ pub(super) fn define_variant(
         #enum_from
 
         impl<'a> wiggle::GuestType<'a> for #ident #enum_lifetime {
+            #[inline]
             fn guest_size() -> u32 {
                 #size
             }
 
+            #[inline]
             fn guest_align() -> usize {
                 #align
             }