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//! All the runtime support necessary for the wasm to cranelift translation is formalized by the
//! traits `FunctionEnvironment` and `ModuleEnvironment`.
//!
//! There are skeleton implementations of these traits in the `dummy` module, and complete
//! implementations in [Wasmtime].
//!
//! [Wasmtime]: https://github.com/bytecodealliance/wasmtime
use crate::state::FuncTranslationState;
use crate::{
DataIndex, ElemIndex, FuncIndex, Global, GlobalIndex, Heap, HeapData, Memory, MemoryIndex,
SignatureIndex, Table, TableIndex, Tag, TagIndex, TypeIndex, WasmError, WasmFuncType,
WasmResult, WasmType,
};
use core::convert::From;
use cranelift_codegen::cursor::FuncCursor;
use cranelift_codegen::ir::immediates::Offset32;
use cranelift_codegen::ir::{self, InstBuilder};
use cranelift_codegen::isa::TargetFrontendConfig;
use cranelift_entity::PrimaryMap;
use cranelift_frontend::FunctionBuilder;
use std::boxed::Box;
use std::string::ToString;
use wasmparser::{FuncValidator, FunctionBody, Operator, ValidatorResources, WasmFeatures};
/// The value of a WebAssembly global variable.
#[derive(Clone, Copy)]
pub enum GlobalVariable {
/// This is a constant global with a value known at compile time.
Const(ir::Value),
/// This is a variable in memory that should be referenced through a `GlobalValue`.
Memory {
/// The address of the global variable storage.
gv: ir::GlobalValue,
/// An offset to add to the address.
offset: Offset32,
/// The global variable's type.
ty: ir::Type,
},
/// This is a global variable that needs to be handled by the environment.
Custom,
}
/// Environment affecting the translation of a WebAssembly.
pub trait TargetEnvironment {
/// Get the information needed to produce Cranelift IR for the given target.
fn target_config(&self) -> TargetFrontendConfig;
/// Whether to enable Spectre mitigations for heap accesses.
fn heap_access_spectre_mitigation(&self) -> bool;
/// Get the Cranelift integer type to use for native pointers.
///
/// This returns `I64` for 64-bit architectures and `I32` for 32-bit architectures.
fn pointer_type(&self) -> ir::Type {
ir::Type::int(u16::from(self.target_config().pointer_bits())).unwrap()
}
/// Get the size of a native pointer, in bytes.
fn pointer_bytes(&self) -> u8 {
self.target_config().pointer_bytes()
}
/// Get the Cranelift reference type to use for the given Wasm reference
/// type.
///
/// By default, this returns `R64` for 64-bit architectures and `R32` for
/// 32-bit architectures. If you override this, then you should also
/// override `FuncEnvironment::{translate_ref_null, translate_ref_is_null}`
/// as well.
fn reference_type(&self, ty: WasmType) -> ir::Type {
let _ = ty;
match self.pointer_type() {
ir::types::I32 => ir::types::R32,
ir::types::I64 => ir::types::R64,
_ => panic!("unsupported pointer type"),
}
}
}
/// Environment affecting the translation of a single WebAssembly function.
///
/// A `FuncEnvironment` trait object is required to translate a WebAssembly function to Cranelift
/// IR. The function environment provides information about the WebAssembly module as well as the
/// runtime environment.
pub trait FuncEnvironment: TargetEnvironment {
/// Is the given parameter of the given function a wasm-level parameter, as opposed to a hidden
/// parameter added for use by the implementation?
fn is_wasm_parameter(&self, signature: &ir::Signature, index: usize) -> bool {
signature.params[index].purpose == ir::ArgumentPurpose::Normal
}
/// Is the given return of the given function a wasm-level parameter, as
/// opposed to a hidden parameter added for use by the implementation?
fn is_wasm_return(&self, signature: &ir::Signature, index: usize) -> bool {
signature.returns[index].purpose == ir::ArgumentPurpose::Normal
}
/// Called after the locals for a function have been parsed, and the number
/// of variables defined by this function is provided.
fn after_locals(&mut self, num_locals_defined: usize) {
drop(num_locals_defined);
}
/// Set up the necessary preamble definitions in `func` to access the global variable
/// identified by `index`.
///
/// The index space covers both imported globals and globals defined by the module.
///
/// Return the global variable reference that should be used to access the global and the
/// WebAssembly type of the global.
fn make_global(
&mut self,
func: &mut ir::Function,
index: GlobalIndex,
) -> WasmResult<GlobalVariable>;
/// Get the heaps for this function environment.
///
/// The returned map should provide heap format details (encoded in
/// `HeapData`) for each `Heap` that was previously returned by
/// `make_heap()`. The translator will first call make_heap for each Wasm
/// memory, and then later when translating code, will invoke `heaps()` to
/// learn how to access the environment's implementation of each memory.
fn heaps(&self) -> &PrimaryMap<Heap, HeapData>;
/// Set up the necessary preamble definitions in `func` to access the linear memory identified
/// by `index`.
///
/// The index space covers both imported and locally declared memories.
fn make_heap(&mut self, func: &mut ir::Function, index: MemoryIndex) -> WasmResult<Heap>;
/// Set up the necessary preamble definitions in `func` to access the table identified
/// by `index`.
///
/// The index space covers both imported and locally declared tables.
fn make_table(&mut self, func: &mut ir::Function, index: TableIndex) -> WasmResult<ir::Table>;
/// Set up a signature definition in the preamble of `func` that can be used for an indirect
/// call with signature `index`.
///
/// The signature may contain additional arguments needed for an indirect call, but the
/// arguments marked as `ArgumentPurpose::Normal` must correspond to the WebAssembly signature
/// arguments.
///
/// The signature will only be used for indirect calls, even if the module has direct function
/// calls with the same WebAssembly type.
fn make_indirect_sig(
&mut self,
func: &mut ir::Function,
index: TypeIndex,
) -> WasmResult<ir::SigRef>;
/// Set up an external function definition in the preamble of `func` that can be used to
/// directly call the function `index`.
///
/// The index space covers both imported functions and functions defined in the current module.
///
/// The function's signature may contain additional arguments needed for a direct call, but the
/// arguments marked as `ArgumentPurpose::Normal` must correspond to the WebAssembly signature
/// arguments.
///
/// The function's signature will only be used for direct calls, even if the module has
/// indirect calls with the same WebAssembly type.
fn make_direct_func(
&mut self,
func: &mut ir::Function,
index: FuncIndex,
) -> WasmResult<ir::FuncRef>;
/// Translate a `call_indirect` WebAssembly instruction at `pos`.
///
/// Insert instructions at `pos` for an indirect call to the function `callee` in the table
/// `table_index` with WebAssembly signature `sig_index`. The `callee` value will have type
/// `i32`.
///
/// The signature `sig_ref` was previously created by `make_indirect_sig()`.
///
/// Return the call instruction whose results are the WebAssembly return values.
#[allow(clippy::too_many_arguments)]
fn translate_call_indirect(
&mut self,
builder: &mut FunctionBuilder,
table_index: TableIndex,
table: ir::Table,
sig_index: TypeIndex,
sig_ref: ir::SigRef,
callee: ir::Value,
call_args: &[ir::Value],
) -> WasmResult<ir::Inst>;
/// Translate a `call` WebAssembly instruction at `pos`.
///
/// Insert instructions at `pos` for a direct call to the function `callee_index`.
///
/// The function reference `callee` was previously created by `make_direct_func()`.
///
/// Return the call instruction whose results are the WebAssembly return values.
fn translate_call(
&mut self,
mut pos: FuncCursor,
_callee_index: FuncIndex,
callee: ir::FuncRef,
call_args: &[ir::Value],
) -> WasmResult<ir::Inst> {
Ok(pos.ins().call(callee, call_args))
}
/// Translate a `memory.grow` WebAssembly instruction.
///
/// The `index` provided identifies the linear memory to grow, and `heap` is the heap reference
/// returned by `make_heap` for the same index.
///
/// The `val` value is the requested memory size in pages.
///
/// Returns the old size (in pages) of the memory.
fn translate_memory_grow(
&mut self,
pos: FuncCursor,
index: MemoryIndex,
heap: Heap,
val: ir::Value,
) -> WasmResult<ir::Value>;
/// Translates a `memory.size` WebAssembly instruction.
///
/// The `index` provided identifies the linear memory to query, and `heap` is the heap reference
/// returned by `make_heap` for the same index.
///
/// Returns the size in pages of the memory.
fn translate_memory_size(
&mut self,
pos: FuncCursor,
index: MemoryIndex,
heap: Heap,
) -> WasmResult<ir::Value>;
/// Translate a `memory.copy` WebAssembly instruction.
///
/// The `index` provided identifies the linear memory to query, and `heap` is the heap reference
/// returned by `make_heap` for the same index.
fn translate_memory_copy(
&mut self,
pos: FuncCursor,
src_index: MemoryIndex,
src_heap: Heap,
dst_index: MemoryIndex,
dst_heap: Heap,
dst: ir::Value,
src: ir::Value,
len: ir::Value,
) -> WasmResult<()>;
/// Translate a `memory.fill` WebAssembly instruction.
///
/// The `index` provided identifies the linear memory to query, and `heap` is the heap reference
/// returned by `make_heap` for the same index.
fn translate_memory_fill(
&mut self,
pos: FuncCursor,
index: MemoryIndex,
heap: Heap,
dst: ir::Value,
val: ir::Value,
len: ir::Value,
) -> WasmResult<()>;
/// Translate a `memory.init` WebAssembly instruction.
///
/// The `index` provided identifies the linear memory to query, and `heap` is the heap reference
/// returned by `make_heap` for the same index. `seg_index` is the index of the segment to copy
/// from.
#[allow(clippy::too_many_arguments)]
fn translate_memory_init(
&mut self,
pos: FuncCursor,
index: MemoryIndex,
heap: Heap,
seg_index: u32,
dst: ir::Value,
src: ir::Value,
len: ir::Value,
) -> WasmResult<()>;
/// Translate a `data.drop` WebAssembly instruction.
fn translate_data_drop(&mut self, pos: FuncCursor, seg_index: u32) -> WasmResult<()>;
/// Translate a `table.size` WebAssembly instruction.
fn translate_table_size(
&mut self,
pos: FuncCursor,
index: TableIndex,
table: ir::Table,
) -> WasmResult<ir::Value>;
/// Translate a `table.grow` WebAssembly instruction.
fn translate_table_grow(
&mut self,
pos: FuncCursor,
table_index: TableIndex,
table: ir::Table,
delta: ir::Value,
init_value: ir::Value,
) -> WasmResult<ir::Value>;
/// Translate a `table.get` WebAssembly instruction.
fn translate_table_get(
&mut self,
builder: &mut FunctionBuilder,
table_index: TableIndex,
table: ir::Table,
index: ir::Value,
) -> WasmResult<ir::Value>;
/// Translate a `table.set` WebAssembly instruction.
fn translate_table_set(
&mut self,
builder: &mut FunctionBuilder,
table_index: TableIndex,
table: ir::Table,
value: ir::Value,
index: ir::Value,
) -> WasmResult<()>;
/// Translate a `table.copy` WebAssembly instruction.
#[allow(clippy::too_many_arguments)]
fn translate_table_copy(
&mut self,
pos: FuncCursor,
dst_table_index: TableIndex,
dst_table: ir::Table,
src_table_index: TableIndex,
src_table: ir::Table,
dst: ir::Value,
src: ir::Value,
len: ir::Value,
) -> WasmResult<()>;
/// Translate a `table.fill` WebAssembly instruction.
fn translate_table_fill(
&mut self,
pos: FuncCursor,
table_index: TableIndex,
dst: ir::Value,
val: ir::Value,
len: ir::Value,
) -> WasmResult<()>;
/// Translate a `table.init` WebAssembly instruction.
#[allow(clippy::too_many_arguments)]
fn translate_table_init(
&mut self,
pos: FuncCursor,
seg_index: u32,
table_index: TableIndex,
table: ir::Table,
dst: ir::Value,
src: ir::Value,
len: ir::Value,
) -> WasmResult<()>;
/// Translate a `elem.drop` WebAssembly instruction.
fn translate_elem_drop(&mut self, pos: FuncCursor, seg_index: u32) -> WasmResult<()>;
/// Translate a `ref.null T` WebAssembly instruction.
///
/// By default, translates into a null reference type.
///
/// Override this if you don't use Cranelift reference types for all Wasm
/// reference types (e.g. you use a raw pointer for `funcref`s) or if the
/// null sentinel is not a null reference type pointer for your type. If you
/// override this method, then you should also override
/// `translate_ref_is_null` as well.
fn translate_ref_null(&mut self, mut pos: FuncCursor, ty: WasmType) -> WasmResult<ir::Value> {
let _ = ty;
Ok(pos.ins().null(self.reference_type(ty)))
}
/// Translate a `ref.is_null` WebAssembly instruction.
///
/// By default, assumes that `value` is a Cranelift reference type, and that
/// a null Cranelift reference type is the null value for all Wasm reference
/// types.
///
/// If you override this method, you probably also want to override
/// `translate_ref_null` as well.
fn translate_ref_is_null(
&mut self,
mut pos: FuncCursor,
value: ir::Value,
) -> WasmResult<ir::Value> {
let is_null = pos.ins().is_null(value);
Ok(pos.ins().uextend(ir::types::I32, is_null))
}
/// Translate a `ref.func` WebAssembly instruction.
fn translate_ref_func(
&mut self,
pos: FuncCursor,
func_index: FuncIndex,
) -> WasmResult<ir::Value>;
/// Translate a `global.get` WebAssembly instruction at `pos` for a global
/// that is custom.
fn translate_custom_global_get(
&mut self,
pos: FuncCursor,
global_index: GlobalIndex,
) -> WasmResult<ir::Value>;
/// Translate a `global.set` WebAssembly instruction at `pos` for a global
/// that is custom.
fn translate_custom_global_set(
&mut self,
pos: FuncCursor,
global_index: GlobalIndex,
val: ir::Value,
) -> WasmResult<()>;
/// Translate an `i32.atomic.wait` or `i64.atomic.wait` WebAssembly instruction.
/// The `index` provided identifies the linear memory containing the value
/// to wait on, and `heap` is the heap reference returned by `make_heap`
/// for the same index. Whether the waited-on value is 32- or 64-bit can be
/// determined by examining the type of `expected`, which must be only I32 or I64.
///
/// Note that the `addr` here is the host linear memory address rather
/// than a relative wasm linear memory address. The type of this value is
/// the same as the host's pointer.
///
/// Returns an i32, which is negative if the helper call failed.
fn translate_atomic_wait(
&mut self,
pos: FuncCursor,
index: MemoryIndex,
heap: Heap,
addr: ir::Value,
expected: ir::Value,
timeout: ir::Value,
) -> WasmResult<ir::Value>;
/// Translate an `atomic.notify` WebAssembly instruction.
/// The `index` provided identifies the linear memory containing the value
/// to wait on, and `heap` is the heap reference returned by `make_heap`
/// for the same index.
///
/// Note that the `addr` here is the host linear memory address rather
/// than a relative wasm linear memory address. The type of this value is
/// the same as the host's pointer.
///
/// Returns an i64, which is negative if the helper call failed.
fn translate_atomic_notify(
&mut self,
pos: FuncCursor,
index: MemoryIndex,
heap: Heap,
addr: ir::Value,
count: ir::Value,
) -> WasmResult<ir::Value>;
/// Emit code at the beginning of every wasm loop.
///
/// This can be used to insert explicit interrupt or safepoint checking at
/// the beginnings of loops.
fn translate_loop_header(&mut self, _builder: &mut FunctionBuilder) -> WasmResult<()> {
// By default, don't emit anything.
Ok(())
}
/// Optional callback for the `FunctionEnvironment` performing this translation to maintain
/// internal state or prepare custom state for the operator to translate
fn before_translate_operator(
&mut self,
_op: &Operator,
_builder: &mut FunctionBuilder,
_state: &FuncTranslationState,
) -> WasmResult<()> {
Ok(())
}
/// Optional callback for the `FunctionEnvironment` performing this translation to maintain
/// internal state or finalize custom state for the operator that was translated
fn after_translate_operator(
&mut self,
_op: &Operator,
_builder: &mut FunctionBuilder,
_state: &FuncTranslationState,
) -> WasmResult<()> {
Ok(())
}
/// Optional callback for the `FuncEnvironment` performing this translation
/// to maintain, prepare, or finalize custom, internal state when we
/// statically determine that a Wasm memory access will unconditionally
/// trap, rendering the rest of the block unreachable. Called just before
/// the unconditional trap is emitted.
fn before_unconditionally_trapping_memory_access(
&mut self,
_builder: &mut FunctionBuilder,
) -> WasmResult<()> {
Ok(())
}
/// Optional callback for the `FunctionEnvironment` performing this translation to perform work
/// before the function body is translated.
fn before_translate_function(
&mut self,
_builder: &mut FunctionBuilder,
_state: &FuncTranslationState,
) -> WasmResult<()> {
Ok(())
}
/// Optional callback for the `FunctionEnvironment` performing this translation to perform work
/// after the function body is translated.
fn after_translate_function(
&mut self,
_builder: &mut FunctionBuilder,
_state: &FuncTranslationState,
) -> WasmResult<()> {
Ok(())
}
/// Returns the target ISA's condition to check for unsigned addition
/// overflowing.
fn unsigned_add_overflow_condition(&self) -> ir::condcodes::IntCC;
/// Whether or not to force relaxed simd instructions to have deterministic
/// lowerings meaning they will produce the same results across all hosts,
/// regardless of the cost to performance.
fn relaxed_simd_deterministic(&self) -> bool {
true
}
/// Whether or not the target being translated for has a native fma
/// instruction. If it does not then when relaxed simd isn't deterministic
/// the translation of the `f32x4.relaxed_fma` instruction, for example,
/// will do a multiplication and then an add instead of the fused version.
fn has_native_fma(&self) -> bool {
false
}
/// Returns whether this is an x86 target, which may alter lowerings of
/// relaxed simd instructions.
fn is_x86(&self) -> bool {
false
}
}
/// An object satisfying the `ModuleEnvironment` trait can be passed as argument to the
/// [`translate_module`](fn.translate_module.html) function. These methods should not be called
/// by the user, they are only for `cranelift-wasm` internal use.
pub trait ModuleEnvironment<'data> {
/// Provides the number of types up front. By default this does nothing, but
/// implementations can use this to preallocate memory if desired.
fn reserve_types(&mut self, _num: u32) -> WasmResult<()> {
Ok(())
}
/// Declares a function signature to the environment.
fn declare_type_func(&mut self, wasm_func_type: WasmFuncType) -> WasmResult<()>;
/// Translates a type index to its signature index, only called for type
/// indices which point to functions.
fn type_to_signature(&self, index: TypeIndex) -> WasmResult<SignatureIndex> {
drop(index);
Err(WasmError::Unsupported("module linking".to_string()))
}
/// Provides the number of imports up front. By default this does nothing, but
/// implementations can use this to preallocate memory if desired.
fn reserve_imports(&mut self, _num: u32) -> WasmResult<()> {
Ok(())
}
/// Declares a function import to the environment.
fn declare_func_import(
&mut self,
index: TypeIndex,
module: &'data str,
field: &'data str,
) -> WasmResult<()>;
/// Declares a table import to the environment.
fn declare_table_import(
&mut self,
table: Table,
module: &'data str,
field: &'data str,
) -> WasmResult<()>;
/// Declares a memory import to the environment.
fn declare_memory_import(
&mut self,
memory: Memory,
module: &'data str,
field: &'data str,
) -> WasmResult<()>;
/// Declares an tag import to the environment.
fn declare_tag_import(
&mut self,
tag: Tag,
module: &'data str,
field: &'data str,
) -> WasmResult<()> {
drop((tag, module, field));
Err(WasmError::Unsupported("wasm tags".to_string()))
}
/// Declares a global import to the environment.
fn declare_global_import(
&mut self,
global: Global,
module: &'data str,
field: &'data str,
) -> WasmResult<()>;
/// Notifies the implementation that all imports have been declared.
fn finish_imports(&mut self) -> WasmResult<()> {
Ok(())
}
/// Provides the number of defined functions up front. By default this does nothing, but
/// implementations can use this to preallocate memory if desired.
fn reserve_func_types(&mut self, _num: u32) -> WasmResult<()> {
Ok(())
}
/// Declares the type (signature) of a local function in the module.
fn declare_func_type(&mut self, index: TypeIndex) -> WasmResult<()>;
/// Provides the number of defined tables up front. By default this does nothing, but
/// implementations can use this to preallocate memory if desired.
fn reserve_tables(&mut self, _num: u32) -> WasmResult<()> {
Ok(())
}
/// Declares a table to the environment.
fn declare_table(&mut self, table: Table) -> WasmResult<()>;
/// Provides the number of defined memories up front. By default this does nothing, but
/// implementations can use this to preallocate memory if desired.
fn reserve_memories(&mut self, _num: u32) -> WasmResult<()> {
Ok(())
}
/// Declares a memory to the environment
fn declare_memory(&mut self, memory: Memory) -> WasmResult<()>;
/// Provides the number of defined tags up front. By default this does nothing, but
/// implementations can use this to preallocate memory if desired.
fn reserve_tags(&mut self, _num: u32) -> WasmResult<()> {
Ok(())
}
/// Declares an tag to the environment
fn declare_tag(&mut self, tag: Tag) -> WasmResult<()> {
drop(tag);
Err(WasmError::Unsupported("wasm tags".to_string()))
}
/// Provides the number of defined globals up front. By default this does nothing, but
/// implementations can use this to preallocate memory if desired.
fn reserve_globals(&mut self, _num: u32) -> WasmResult<()> {
Ok(())
}
/// Declares a global to the environment.
fn declare_global(&mut self, global: Global) -> WasmResult<()>;
/// Provides the number of exports up front. By default this does nothing, but
/// implementations can use this to preallocate memory if desired.
fn reserve_exports(&mut self, _num: u32) -> WasmResult<()> {
Ok(())
}
/// Declares a function export to the environment.
fn declare_func_export(&mut self, func_index: FuncIndex, name: &'data str) -> WasmResult<()>;
/// Declares a table export to the environment.
fn declare_table_export(&mut self, table_index: TableIndex, name: &'data str)
-> WasmResult<()>;
/// Declares a memory export to the environment.
fn declare_memory_export(
&mut self,
memory_index: MemoryIndex,
name: &'data str,
) -> WasmResult<()>;
/// Declares an tag export to the environment.
fn declare_tag_export(&mut self, tag_index: TagIndex, name: &'data str) -> WasmResult<()> {
drop((tag_index, name));
Err(WasmError::Unsupported("wasm tags".to_string()))
}
/// Declares a global export to the environment.
fn declare_global_export(
&mut self,
global_index: GlobalIndex,
name: &'data str,
) -> WasmResult<()>;
/// Notifies the implementation that all exports have been declared.
fn finish_exports(&mut self) -> WasmResult<()> {
Ok(())
}
/// Declares the optional start function.
fn declare_start_func(&mut self, index: FuncIndex) -> WasmResult<()>;
/// Provides the number of element initializers up front. By default this does nothing, but
/// implementations can use this to preallocate memory if desired.
fn reserve_table_elements(&mut self, _num: u32) -> WasmResult<()> {
Ok(())
}
/// Fills a declared table with references to functions in the module.
fn declare_table_elements(
&mut self,
table_index: TableIndex,
base: Option<GlobalIndex>,
offset: u32,
elements: Box<[FuncIndex]>,
) -> WasmResult<()>;
/// Declare a passive element segment.
fn declare_passive_element(
&mut self,
index: ElemIndex,
elements: Box<[FuncIndex]>,
) -> WasmResult<()>;
/// Indicates that a declarative element segment was seen in the wasm
/// module.
fn declare_elements(&mut self, elements: Box<[FuncIndex]>) -> WasmResult<()> {
drop(elements);
Ok(())
}
/// Provides the number of passive data segments up front.
///
/// By default this does nothing, but implementations may use this to
/// pre-allocate memory if desired.
fn reserve_passive_data(&mut self, count: u32) -> WasmResult<()> {
let _ = count;
Ok(())
}
/// Declare a passive data segment.
fn declare_passive_data(&mut self, data_index: DataIndex, data: &'data [u8]) -> WasmResult<()>;
/// Indicates how many functions the code section reports and the byte
/// offset of where the code sections starts.
fn reserve_function_bodies(&mut self, bodies: u32, code_section_offset: u64) {
drop((bodies, code_section_offset));
}
/// Provides the contents of a function body.
fn define_function_body(
&mut self,
validator: FuncValidator<ValidatorResources>,
body: FunctionBody<'data>,
) -> WasmResult<()>;
/// Provides the number of data initializers up front. By default this does nothing, but
/// implementations can use this to preallocate memory if desired.
fn reserve_data_initializers(&mut self, _num: u32) -> WasmResult<()> {
Ok(())
}
/// Fills a declared memory with bytes at module instantiation.
fn declare_data_initialization(
&mut self,
memory_index: MemoryIndex,
base: Option<GlobalIndex>,
offset: u64,
data: &'data [u8],
) -> WasmResult<()>;
/// Declares the name of a module to the environment.
///
/// By default this does nothing, but implementations can use this to read
/// the module name subsection of the custom name section if desired.
fn declare_module_name(&mut self, _name: &'data str) {}
/// Declares the name of a function to the environment.
///
/// By default this does nothing, but implementations can use this to read
/// the function name subsection of the custom name section if desired.
fn declare_func_name(&mut self, _func_index: FuncIndex, _name: &'data str) {}
/// Declares the name of a function's local to the environment.
///
/// By default this does nothing, but implementations can use this to read
/// the local name subsection of the custom name section if desired.
fn declare_local_name(&mut self, _func_index: FuncIndex, _local_index: u32, _name: &'data str) {
}
/// Indicates that a custom section has been found in the wasm file
fn custom_section(&mut self, _name: &'data str, _data: &'data [u8]) -> WasmResult<()> {
Ok(())
}
/// Returns the list of enabled wasm features this translation will be using.
fn wasm_features(&self) -> WasmFeatures {
WasmFeatures::default()
}
}