Plumb wasm memory types further down in Winch

This commit plumbs `wasmtime_environ::Memory` further down the stack in
Winch to where heaps are processed. This avoids an extra layer of
indirection through a `Heap` type which peels apart a `Memory` to pick
out a few fields. In the future this'll be used with more helpers on
`Memory` to simplify the static/dynamic memory cases.

crates/environ/src/types.rs

@@ -1797,6 +1797,19 @@ impl Memory {
             IndexType::I32 => WASM32_MAX_SIZE,
         }
     }
+
+    /// Returns the static size of this heap in bytes at runtime, if available.
+    ///
+    /// This is only computable when the minimum size equals the maximum size.
+    pub fn static_heap_size(&self) -> Option<u64> {
+        let min = self.minimum_byte_size().ok()?;
+        let max = self.maximum_byte_size().ok()?;
+        if min == max {
+            Some(min)
+        } else {
+            None
+        }
+    }
 }
 
 #[derive(Copy, Clone, Debug)]

winch/codegen/src/codegen/bounds.rs

@@ -1,14 +1,15 @@
 //! Exposes heap bounds checks functionality for WebAssembly.
 //! Bounds checks in WebAssembly are critical for safety, so extreme caution is
 //! recommended when working on this area of Winch.
-use super::env::{HeapData, HeapStyle};
+use super::env::HeapData;
 use crate::{
     abi::{scratch, vmctx},
     codegen::CodeGenContext,
     isa::reg::{writable, Reg},
     masm::{IntCmpKind, MacroAssembler, OperandSize, RegImm, TrapCode},
     stack::TypedReg,
 };
+use wasmtime_environ::Signed;
 
 /// A newtype to represent an immediate offset argument for a heap access.
 #[derive(Debug, Copy, Clone)]
@@ -90,12 +91,11 @@ where
     M: MacroAssembler,
 {
     let dst = context.any_gpr(masm);
-    match (heap.max_size, &heap.style) {
+    match heap.memory.static_heap_size() {
         // Constant size, no need to perform a load.
-        (Some(max_size), HeapStyle::Dynamic) if heap.min_size == max_size => {
-            masm.mov(writable!(dst), RegImm::i64(max_size as i64), ptr_size)
-        }
-        (_, HeapStyle::Dynamic) => {
+        Some(size) => masm.mov(writable!(dst), RegImm::i64(size.signed()), ptr_size),
+
+        None => {
             let scratch = scratch!(M);
             let base = if let Some(offset) = heap.import_from {
                 let addr = masm.address_at_vmctx(offset);
@@ -107,10 +107,9 @@ where
             let addr = masm.address_at_reg(base, heap.current_length_offset);
             masm.load_ptr(addr, writable!(dst));
         }
-        (_, HeapStyle::Static { .. }) => unreachable!("Loading dynamic bounds of a static heap"),
     }
 
-    Bounds::from_typed_reg(TypedReg::new(heap.ty, dst))
+    Bounds::from_typed_reg(TypedReg::new(heap.index_type(), dst))
 }
 
 /// This function ensures the following:

winch/codegen/src/codegen/env.rs

@@ -11,9 +11,9 @@ use std::collections::{
 use std::mem;
 use wasmparser::BlockType;
 use wasmtime_environ::{
-    BuiltinFunctionIndex, FuncIndex, GlobalIndex, Memory, MemoryIndex, MemoryStyle,
-    ModuleTranslation, ModuleTypesBuilder, PrimaryMap, PtrSize, Table, TableIndex, Tunables,
-    TypeConvert, TypeIndex, VMOffsets, WasmHeapType, WasmValType,
+    BuiltinFunctionIndex, FuncIndex, GlobalIndex, IndexType, Memory, MemoryIndex,
+    ModuleTranslation, ModuleTypesBuilder, PrimaryMap, PtrSize, Table, TableIndex, TypeConvert,
+    TypeIndex, VMOffsets, WasmHeapType, WasmValType,
 };
 
 #[derive(Debug, Clone, Copy)]
@@ -42,20 +42,6 @@ pub struct TableData {
     pub(crate) current_elements_size: OperandSize,
 }
 
-/// Style of the heap.
-#[derive(Debug, Copy, Clone)]
-pub enum HeapStyle {
-    /// Static heap, which has a fixed address.
-    Static {
-        /// The heap bound in bytes, not including the bytes for the offset
-        /// guard pages.
-        bound: u64,
-    },
-    /// Dynamic heap, which can be relocated to a different address when grown.
-    /// The bounds are calculated at runtime on every access.
-    Dynamic,
-}
-
 /// Heap metadata.
 ///
 /// Heaps represent a WebAssembly linear memory.
@@ -71,19 +57,17 @@ pub struct HeapData {
     /// If the WebAssembly memory is imported, this field contains the offset to locate the
     /// base of the heap.
     pub import_from: Option<u32>,
-    /// The memory type (32 or 64).
-    pub ty: WasmValType,
-    /// The style of the heap.
-    pub style: HeapStyle,
-    /// The guaranteed minimum size, in bytes.
-    pub min_size: u64,
-    /// The maximum heap size in bytes.
-    pub max_size: Option<u64>,
-    /// The log2 of this memory's page size, in bytes.
-    ///
-    /// By default the page size is 64KiB (0x10000; 2**16; 1<<16; 65536) but the
-    /// custom-page-sizes proposal allows opting into a page size of `1`.
-    pub page_size_log2: u8,
+    /// The memory type this heap is associated with.
+    pub memory: Memory,
+}
+
+impl HeapData {
+    pub fn index_type(&self) -> WasmValType {
+        match self.memory.idx_type {
+            IndexType::I32 => WasmValType::I32,
+            IndexType::I64 => WasmValType::I64,
+        }
+    }
 }
 
 /// A function callee.
@@ -114,8 +98,6 @@ pub struct FuncEnv<'a, 'translation: 'a, 'data: 'translation, P: PtrSize> {
     pub types: &'translation ModuleTypesBuilder,
     /// The built-in functions available to the JIT code.
     pub builtins: &'translation mut BuiltinFunctions,
-    /// Configurable code generation options.
-    tunables: &'translation Tunables,
     /// Track resolved table information.
     resolved_tables: HashMap<TableIndex, TableData>,
     /// Track resolved heap information.
@@ -151,15 +133,13 @@ impl<'a, 'translation, 'data, P: PtrSize> FuncEnv<'a, 'translation, 'data, P> {
         translation: &'translation ModuleTranslation<'data>,
         types: &'translation ModuleTypesBuilder,
         builtins: &'translation mut BuiltinFunctions,
-        tunables: &'translation Tunables,
         isa: &dyn TargetIsa,
         ptr_type: WasmValType,
     ) -> Self {
         Self {
             vmoffsets,
             translation,
             types,
-            tunables,
             resolved_tables: HashMap::new(),
             resolved_heaps: HashMap::new(),
             resolved_callees: HashMap::new(),
@@ -292,21 +272,12 @@ impl<'a, 'translation, 'data, P: PtrSize> FuncEnv<'a, 'translation, 'data, P> {
                     };
 
                 let memory = &self.translation.module.memories[index];
-                let (min_size, max_size) = heap_limits(memory);
-                let style = heap_style_and_offset_guard_size(memory, self.tunables);
 
                 *entry.insert(HeapData {
                     offset: base_offset,
                     import_from,
                     current_length_offset,
-                    style,
-                    ty: match memory.idx_type {
-                        wasmtime_environ::IndexType::I32 => WasmValType::I32,
-                        wasmtime_environ::IndexType::I64 => WasmValType::I64,
-                    },
-                    min_size,
-                    max_size,
-                    page_size_log2: memory.page_size_log2,
+                    memory: *memory,
                 })
             }
         }
@@ -420,25 +391,3 @@ impl<'a, 'data> TypeConverter<'a, 'data> {
         Self { translation, types }
     }
 }
-
-fn heap_style_and_offset_guard_size(memory: &Memory, tunables: &Tunables) -> HeapStyle {
-    let style = MemoryStyle::for_memory(*memory, tunables);
-    match style {
-        MemoryStyle::Static { byte_reservation } => HeapStyle::Static {
-            bound: byte_reservation,
-        },
-
-        MemoryStyle::Dynamic { .. } => HeapStyle::Dynamic,
-    }
-}
-
-fn heap_limits(memory: &Memory) -> (u64, Option<u64>) {
-    (
-        memory.minimum_byte_size().unwrap_or_else(|_| {
-            // 2^64 as a minimum doesn't fin in a 64 bit integer.
-            // So in this case, the minimum is clamped to u64::MAX.
-            u64::MAX
-        }),
-        memory.maximum_byte_size().ok(),
-    )
-}

winch/codegen/src/codegen/mod.rs

@@ -8,20 +8,19 @@ use crate::{
     stack::TypedReg,
 };
 use anyhow::Result;
+use cranelift_codegen::{
+    binemit::CodeOffset,
+    ir::{RelSourceLoc, SourceLoc},
+};
 use smallvec::SmallVec;
 use wasmparser::{
     BinaryReader, FuncValidator, MemArg, Operator, ValidatorResources, VisitOperator,
 };
+use wasmtime_cranelift::{TRAP_BAD_SIGNATURE, TRAP_TABLE_OUT_OF_BOUNDS};
 use wasmtime_environ::{
-    GlobalIndex, MemoryIndex, PtrSize, TableIndex, Tunables, TypeIndex, WasmHeapType, WasmValType,
-    FUNCREF_MASK,
-};
-
-use cranelift_codegen::{
-    binemit::CodeOffset,
-    ir::{RelSourceLoc, SourceLoc},
+    GlobalIndex, MemoryIndex, MemoryStyle, PtrSize, TableIndex, Tunables, TypeIndex, WasmHeapType,
+    WasmValType, FUNCREF_MASK,
 };
-use wasmtime_cranelift::{TRAP_BAD_SIGNATURE, TRAP_TABLE_OUT_OF_BOUNDS};
 
 mod context;
 pub(crate) use context::*;
@@ -585,19 +584,24 @@ where
         let memory_index = MemoryIndex::from_u32(memarg.memory);
         let heap = self.env.resolve_heap(memory_index);
         let index = Index::from_typed_reg(self.context.pop_to_reg(self.masm, None));
-        let offset =
-            bounds::ensure_index_and_offset(self.masm, index, memarg.offset, heap.ty.into());
+        let offset = bounds::ensure_index_and_offset(
+            self.masm,
+            index,
+            memarg.offset,
+            heap.index_type().into(),
+        );
         let offset_with_access_size = add_offset_and_access_size(offset, access_size);
 
-        let addr = match heap.style {
+        let style = MemoryStyle::for_memory(heap.memory, self.tunables);
+        let addr = match style {
             // == Dynamic Heaps ==
 
             // Account for the general case for dynamic memories. The access is
             // out of bounds if:
             // * index + offset + access_size overflows
             //   OR
             // * index + offset + access_size > bound
-            HeapStyle::Dynamic => {
+            MemoryStyle::Dynamic { .. } => {
                 let bounds =
                     bounds::load_dynamic_heap_bounds(&mut self.context, self.masm, &heap, ptr_size);
 
@@ -621,7 +625,7 @@ where
                 self.masm.mov(
                     writable!(index_offset_and_access_size),
                     index_reg.into(),
-                    heap.ty.into(),
+                    heap.index_type().into(),
                 );
                 // Perform
                 // index = index + offset + access_size, trapping if the
@@ -675,7 +679,9 @@ where
             // optimizing the work that the compiler has to do until the
             // reachability is restored or when reaching the end of the
             // function.
-            HeapStyle::Static { bound } if offset_with_access_size > bound => {
+            MemoryStyle::Static { byte_reservation }
+                if offset_with_access_size > byte_reservation =>
+            {
                 self.emit_fuel_increment();
                 self.masm.trap(TrapCode::HEAP_OUT_OF_BOUNDS);
                 self.context.reachable = false;
@@ -708,10 +714,10 @@ where
             // * If the heap type is 32-bits, the offset is at most u32::MAX, so
             // no  adjustment is needed as part of
             // [bounds::ensure_index_and_offset].
-            HeapStyle::Static { bound }
-                if heap.ty == WasmValType::I32
+            MemoryStyle::Static { byte_reservation }
+                if heap.index_type() == WasmValType::I32
                     && u64::from(u32::MAX)
-                        <= u64::from(bound) + u64::from(self.tunables.memory_guard_size)
+                        <= byte_reservation + u64::from(self.tunables.memory_guard_size)
                             - offset_with_access_size =>
             {
                 let addr = self.context.any_gpr(self.masm);
@@ -726,8 +732,8 @@ where
             //
             // bound - (offset + access_size) cannot wrap, because we already
             // checked that (offset + access_size) > bound, above.
-            HeapStyle::Static { bound } => {
-                let bounds = Bounds::from_u64(bound);
+            MemoryStyle::Static { byte_reservation } => {
+                let bounds = Bounds::from_u64(byte_reservation);
                 let addr = bounds::load_heap_addr_checked(
                     self.masm,
                     &mut self.context,
@@ -908,14 +914,14 @@ where
             .address_at_reg(base, heap_data.current_length_offset);
         self.masm.load_ptr(size_addr, writable!(size_reg));
         // Emit a shift to get the size in pages rather than in bytes.
-        let dst = TypedReg::new(heap_data.ty, size_reg);
-        let pow = heap_data.page_size_log2;
+        let dst = TypedReg::new(heap_data.index_type(), size_reg);
+        let pow = heap_data.memory.page_size_log2;
         self.masm.shift_ir(
             writable!(dst.reg),
             pow as u64,
             dst.into(),
             ShiftKind::ShrU,
-            heap_data.ty.into(),
+            heap_data.index_type().into(),
         );
         self.context.stack.push(dst.into());
     }

winch/codegen/src/isa/aarch64/mod.rs

@@ -104,7 +104,6 @@ impl TargetIsa for Aarch64 {
             translation,
             types,
             builtins,
-            tunables,
             self,
             abi::Aarch64ABI::ptr_type(),
         );

winch/codegen/src/isa/x64/mod.rs

@@ -114,7 +114,6 @@ impl TargetIsa for X64 {
             translation,
             types,
             builtins,
-            tunables,
             self,
             abi::X64ABI::ptr_type(),
         );

winch/codegen/src/visitor.rs

@@ -1653,7 +1653,7 @@ where
         // The memory32_grow builtin returns a pointer type, therefore we must
         // ensure that the return type is representative of the address space of
         // the heap type.
-        match (self.env.ptr_type(), heap.ty) {
+        match (self.env.ptr_type(), heap.index_type()) {
             (WasmValType::I64, WasmValType::I64) => {}
             // When the heap type is smaller than the pointer type, we adjust
             // the result of the memory32_grow builtin.