Implemented shared memory for Wasmer in preparation for multithreading

Fixed linter

Fixed clippy

Cleaned up some merge leftover

lib/api/src/js/mod.rs

@@ -73,7 +73,6 @@ pub use crate::js::value::Value as Val;
 
 pub mod vm {
     //! The `vm` module re-exports wasmer-vm types.
-
     pub use crate::js::export::VMMemory;
 }
 

lib/api/src/sys/imports.rs

@@ -1,11 +1,12 @@
 //! The import module contains the implementation data structures and helper functions used to
 //! manipulate and access a wasm module's imports including memories, tables, globals, and
 //! functions.
-use crate::{Exports, Extern, Module};
+use crate::{AsStoreMut, Exports, Extern, Memory, Module};
 use std::collections::HashMap;
 use std::fmt;
 use wasmer_compiler::LinkError;
 use wasmer_types::ImportError;
+use wasmer_vm::VMSharedMemory;
 
 /// All of the import data used when instantiating.
 ///
@@ -111,6 +112,36 @@ impl Imports {
             .insert((ns.to_string(), name.to_string()), val.into());
     }
 
+    /// Imports (any) shared memory into the imports.
+    /// (if the module does not import memory then this function is ignored)
+    pub fn import_shared_memory(
+        &mut self,
+        module: &Module,
+        store: &mut impl AsStoreMut,
+    ) -> Option<VMSharedMemory> {
+        // Determine if shared memory needs to be created and imported
+        let shared_memory = module
+            .imports()
+            .memories()
+            .next()
+            .map(|a| *a.ty())
+            .map(|ty| {
+                let style = store.as_store_ref().tunables().memory_style(&ty);
+                VMSharedMemory::new(&ty, &style).unwrap()
+            });
+
+        if let Some(memory) = shared_memory {
+            self.define(
+                "env",
+                "memory",
+                Memory::new_from_existing(store, memory.clone().into()),
+            );
+            Some(memory)
+        } else {
+            None
+        }
+    }
+
     /// Returns the contents of a namespace as an `Exports`.
     ///
     /// Returns `None` if the namespace doesn't exist.

lib/api/src/sys/mod.rs

@@ -57,8 +57,8 @@ pub mod vm {
     //! The `vm` module re-exports wasmer-vm types.
 
     pub use wasmer_vm::{
-        MemoryError, MemoryStyle, TableStyle, VMExtern, VMMemory, VMMemoryDefinition, VMTable,
+        MemoryError, MemoryStyle, TableStyle, VMExtern, VMMemory, VMMemoryDefinition,
-        VMTableDefinition,
+        VMOwnedMemory, VMSharedMemory, VMTable, VMTableDefinition,
     };
 }
 

lib/cli/src/commands/run/wasi.rs

@@ -104,7 +104,8 @@ impl Wasi {
             is_wasix_module(module),
             std::sync::atomic::Ordering::Release,
         );
-        let import_object = import_object_for_all_wasi_versions(store, &wasi_env.env);
+        let mut import_object = import_object_for_all_wasi_versions(store, &wasi_env.env);
+        import_object.import_shared_memory(module, store);
         let instance = Instance::new(store, module, &import_object)?;
         let memory = instance.exports.get_memory("memory")?;
         wasi_env.data_mut(store).set_memory(memory.clone());

lib/compiler-cranelift/src/translator/code_translator.rs

@@ -1063,26 +1063,48 @@ pub fn translate_operator<FE: FuncEnvironment + ?Sized>(
             assert!(builder.func.dfg.value_type(expected) == implied_ty);
             // `fn translate_atomic_wait` can inspect the type of `expected` to figure out what
             // code it needs to generate, if it wants.
-            let res = environ.translate_atomic_wait(
+            match environ.translate_atomic_wait(
                 builder.cursor(),
                 heap_index,
                 heap,
                 addr,
                 expected,
                 timeout,
-            )?;
+            ) {
+                Ok(res) => {
                     state.push1(res);
                 }
+                Err(wasmer_types::WasmError::Unsupported(_err)) => {
+                    // If multiple threads hit a mutex then the function will fail
+                    builder.ins().trap(ir::TrapCode::UnreachableCodeReached);
+                    state.reachable = false;
+                }
+                Err(err) => {
+                    return Err(err);
+                }
+            };
+        }
         Operator::MemoryAtomicNotify { memarg } => {
             let heap_index = MemoryIndex::from_u32(memarg.memory);
             let heap = state.get_heap(builder.func, memarg.memory, environ)?;
             let count = state.pop1(); // 32 (fixed)
             let addr = state.pop1(); // 32 (fixed)
             let addr = fold_atomic_mem_addr(addr, memarg, I32, builder);
-            let res =
+            match environ.translate_atomic_notify(builder.cursor(), heap_index, heap, addr, count) {
-                environ.translate_atomic_notify(builder.cursor(), heap_index, heap, addr, count)?;
+                Ok(res) => {
                     state.push1(res);
                 }
+                Err(wasmer_types::WasmError::Unsupported(_err)) => {
+                    // Simple return a zero as this function is needed for the __wasi_init_memory function
+                    // but the equivalent notify.wait will not be called (as only one thread calls __start)
+                    // hence these atomic operations are not needed
+                    state.push1(builder.ins().iconst(I32, i64::from(0)));
+                }
+                Err(err) => {
+                    return Err(err);
+                }
+            };
+        }
         Operator::I32AtomicLoad { memarg } => {
             translate_atomic_load(I32, I32, memarg, builder, state, environ)?
         }

lib/compiler/src/translator/environ.rs

@@ -1,7 +1,6 @@
 // This file contains code from external sources.
 // Attributions: https://github.com/wasmerio/wasmer/blob/master/ATTRIBUTIONS.md
 use super::state::ModuleTranslationState;
-use crate::lib::std::borrow::ToOwned;
 use crate::lib::std::string::ToString;
 use crate::lib::std::{boxed::Box, string::String, vec::Vec};
 use crate::translate_module;
@@ -9,13 +8,13 @@ use crate::wasmparser::{Operator, Range, Type};
 use std::convert::{TryFrom, TryInto};
 use wasmer_types::entity::PrimaryMap;
 use wasmer_types::FunctionType;
+use wasmer_types::WasmResult;
 use wasmer_types::{
     CustomSectionIndex, DataIndex, DataInitializer, DataInitializerLocation, ElemIndex,
     ExportIndex, FunctionIndex, GlobalIndex, GlobalInit, GlobalType, ImportIndex,
     LocalFunctionIndex, MemoryIndex, MemoryType, ModuleInfo, SignatureIndex, TableIndex,
     TableInitializer, TableType,
 };
-use wasmer_types::{WasmError, WasmResult};
 
 /// Contains function data: bytecode and its offset in the module.
 #[derive(Hash)]
@@ -254,11 +253,6 @@ impl<'data> ModuleEnvironment<'data> {
     }
 
     pub(crate) fn declare_memory(&mut self, memory: MemoryType) -> WasmResult<()> {
-        if memory.shared {
-            return Err(WasmError::Unsupported(
-                "shared memories are not supported yet".to_owned(),
-            ));
-        }
         self.module.memories.push(memory);
         Ok(())
     }

lib/vm/src/instance/mod.rs

@@ -16,10 +16,11 @@ use crate::trap::{catch_traps, Trap, TrapCode};
 use crate::vmcontext::{
     memory_copy, memory_fill, VMBuiltinFunctionsArray, VMCallerCheckedAnyfunc, VMContext,
     VMFunctionContext, VMFunctionImport, VMFunctionKind, VMGlobalDefinition, VMGlobalImport,
-    VMMemoryImport, VMSharedSignatureIndex, VMTableDefinition, VMTableImport, VMTrampoline,
+    VMMemoryDefinition, VMMemoryImport, VMSharedSignatureIndex, VMTableDefinition, VMTableImport,
+    VMTrampoline,
 };
+use crate::LinearMemory;
 use crate::{FunctionBodyPtr, MaybeInstanceOwned, TrapHandlerFn, VMFunctionBody};
-use crate::{LinearMemory, VMMemoryDefinition};
 use crate::{VMFuncRef, VMFunction, VMGlobal, VMMemory, VMTable};
 pub use allocator::InstanceAllocator;
 use memoffset::offset_of;

lib/vm/src/lib.rs

@@ -45,7 +45,7 @@ pub use crate::function_env::VMFunctionEnvironment;
 pub use crate::global::*;
 pub use crate::imports::Imports;
 pub use crate::instance::{InstanceAllocator, InstanceHandle};
-pub use crate::memory::{initialize_memory_with_data, LinearMemory, VMMemory};
+pub use crate::memory::{initialize_memory_with_data, LinearMemory, VMMemory, VMOwnedMemory, VMSharedMemory};
 pub use crate::mmap::Mmap;
 pub use crate::probestack::PROBESTACK;
 pub use crate::sig_registry::SignatureRegistry;

lib/vm/src/memory.rs

@@ -12,6 +12,7 @@ use std::cell::UnsafeCell;
 use std::convert::TryInto;
 use std::ptr::NonNull;
 use std::slice;
+use std::sync::{Arc, RwLock};
 use wasmer_types::{Bytes, MemoryError, MemoryStyle, MemoryType, Pages};
 
 // The memory mapped area
@@ -156,6 +157,18 @@ pub struct VMOwnedMemory {
 unsafe impl Send for VMOwnedMemory {}
 unsafe impl Sync for VMOwnedMemory {}
 
+/// A shared linear memory instance.
+#[derive(Debug, Clone)]
+pub struct VMSharedMemory {
+    // The underlying allocation.
+    mmap: Arc<RwLock<WasmMmap>>,
+    // Configuration of this memory
+    config: VMMemoryConfig,
+}
+
+unsafe impl Send for VMSharedMemory {}
+unsafe impl Sync for VMSharedMemory {}
+
 impl VMOwnedMemory {
     /// Create a new linear memory instance with specified minimum and maximum number of wasm pages.
     ///
@@ -259,6 +272,16 @@ impl VMOwnedMemory {
     }
 }
 
+impl VMOwnedMemory {
+    /// Converts this owned memory into shared memory
+    pub fn to_shared(self) -> VMSharedMemory {
+        VMSharedMemory {
+            mmap: Arc::new(RwLock::new(self.mmap)),
+            config: self.config,
+        }
+    }
+}
+
 impl LinearMemory for VMOwnedMemory {
     /// Returns the type for this memory.
     fn ty(&self) -> MemoryType {
@@ -295,12 +318,85 @@ impl LinearMemory for VMOwnedMemory {
     }
 }
 
+impl VMSharedMemory {
+    /// Create a new linear memory instance with specified minimum and maximum number of wasm pages.
+    ///
+    /// This creates a `Memory` with owned metadata: this can be used to create a memory
+    /// that will be imported into Wasm modules.
+    pub fn new(memory: &MemoryType, style: &MemoryStyle) -> Result<Self, MemoryError> {
+        Ok(VMOwnedMemory::new(memory, style)?.to_shared())
+    }
+
+    /// Create a new linear memory instance with specified minimum and maximum number of wasm pages.
+    ///
+    /// This creates a `Memory` with metadata owned by a VM, pointed to by
+    /// `vm_memory_location`: this can be used to create a local memory.
+    ///
+    /// # Safety
+    /// - `vm_memory_location` must point to a valid location in VM memory.
+    pub unsafe fn from_definition(
+        memory: &MemoryType,
+        style: &MemoryStyle,
+        vm_memory_location: NonNull<VMMemoryDefinition>,
+    ) -> Result<Self, MemoryError> {
+        Ok(VMOwnedMemory::from_definition(memory, style, vm_memory_location)?.to_shared())
+    }
+}
+
+impl LinearMemory for VMSharedMemory {
+    /// Returns the type for this memory.
+    fn ty(&self) -> MemoryType {
+        let minimum = {
+            let guard = self.mmap.read().unwrap();
+            guard.size()
+        };
+        self.config.ty(minimum)
+    }
+
+    /// Returns the size of hte memory in pages
+    fn size(&self) -> Pages {
+        let guard = self.mmap.read().unwrap();
+        guard.size()
+    }
+
+    /// Returns the memory style for this memory.
+    fn style(&self) -> MemoryStyle {
+        self.config.style()
+    }
+
+    /// Grow memory by the specified amount of wasm pages.
+    ///
+    /// Returns `None` if memory can't be grown by the specified amount
+    /// of wasm pages.
+    fn grow(&mut self, delta: Pages) -> Result<Pages, MemoryError> {
+        let mut guard = self.mmap.write().unwrap();
+        guard.grow(delta, self.config.clone())
+    }
+
+    /// Return a `VMMemoryDefinition` for exposing the memory to compiled wasm code.
+    fn vmmemory(&self) -> NonNull<VMMemoryDefinition> {
+        let guard = self.mmap.read().unwrap();
+        guard.vm_memory_definition.as_ptr()
+    }
+
+    /// Owned memory can not be cloned (this will always return None)
+    fn try_clone(&self) -> Option<Box<dyn LinearMemory + 'static>> {
+        None
+    }
+}
+
 impl From<VMOwnedMemory> for VMMemory {
     fn from(mem: VMOwnedMemory) -> Self {
         Self(Box::new(mem))
     }
 }
 
+impl From<VMSharedMemory> for VMMemory {
+    fn from(mem: VMSharedMemory) -> Self {
+        Self(Box::new(mem))
+    }
+}
+
 /// Represents linear memory that can be either owned or shared
 #[derive(Debug)]
 pub struct VMMemory(pub Box<dyn LinearMemory + 'static>);
@@ -357,8 +453,12 @@ impl VMMemory {
     ///
     /// This creates a `Memory` with owned metadata: this can be used to create a memory
     /// that will be imported into Wasm modules.
-    pub fn new(memory: &MemoryType, style: &MemoryStyle) -> Result<Self, MemoryError> {
+    pub fn new(memory: &MemoryType, style: &MemoryStyle) -> Result<VMMemory, MemoryError> {
-        Ok(Self(Box::new(VMOwnedMemory::new(memory, style)?)))
+        Ok(if memory.shared {
+            Self(Box::new(VMSharedMemory::new(memory, style)?))
+        } else {
+            Self(Box::new(VMOwnedMemory::new(memory, style)?))
+        })
     }
 
     /// Returns the number of pages in the allocated memory block
@@ -377,12 +477,20 @@ impl VMMemory {
         memory: &MemoryType,
         style: &MemoryStyle,
         vm_memory_location: NonNull<VMMemoryDefinition>,
-    ) -> Result<Self, MemoryError> {
+    ) -> Result<VMMemory, MemoryError> {
-        Ok(Self(Box::new(VMOwnedMemory::from_definition(
+        Ok(if memory.shared {
+            Self(Box::new(VMSharedMemory::from_definition(
                 memory,
                 style,
                 vm_memory_location,
-        )?)))
+            )?))
+        } else {
+            Self(Box::new(VMOwnedMemory::from_definition(
+                memory,
+                style,
+                vm_memory_location,
+            )?))
+        })
     }
 
     /// Creates VMMemory from a custom implementation - the following into implementations

lib/vm/src/store.rs

@@ -78,6 +78,11 @@ impl StoreObjects {
         self.id
     }
 
+    /// Sets the ID of this store
+    pub fn set_id(&mut self, id: StoreId) {
+        self.id = id;
+    }
+
     /// Returns a pair of mutable references from two handles.
     ///
     /// Panics if both handles point to the same object.