cranelift-wasm: Remove ModuleTranslationState (#5365)

* cranelift-wasm: Remove `ModuleTranslationState`

We were putting data into it, but never reading data out of it. Can be removed.

* cranelift-wasm: move `funct_state.rs` sub module to `state.rs`

Since it is the only submodule of `state` it can just be the whole `state`
module.

cranelift/wasm/src/lib.rs

@@ -61,8 +61,7 @@ pub use crate::environ::{
 };
 pub use crate::func_translator::FuncTranslator;
 pub use crate::module_translator::translate_module;
-pub use crate::state::func_state::FuncTranslationState;
+pub use crate::state::FuncTranslationState;
-pub use crate::state::module_state::ModuleTranslationState;
 pub use crate::translation_utils::*;
 pub use cranelift_frontend::FunctionBuilder;
 pub use wasmtime_types::*;

cranelift/wasm/src/module_translator.rs

@@ -6,7 +6,6 @@ use crate::sections_translator::{
     parse_global_section, parse_import_section, parse_memory_section, parse_name_section,
     parse_start_section, parse_table_section, parse_tag_section, parse_type_section,
 };
-use crate::state::ModuleTranslationState;
 use crate::WasmResult;
 use cranelift_codegen::timing;
 use std::prelude::v1::*;
@@ -17,9 +16,8 @@ use wasmparser::{NameSectionReader, Parser, Payload, Validator};
 pub fn translate_module<'data>(
     data: &'data [u8],
     environ: &mut dyn ModuleEnvironment<'data>,
-) -> WasmResult<ModuleTranslationState> {
+) -> WasmResult<()> {
     let _tt = timing::wasm_translate_module();
-    let mut module_translation_state = ModuleTranslationState::new();
     let mut validator = Validator::new_with_features(environ.wasm_features());
 
     for payload in Parser::new(0).parse_all(data) {
@@ -37,7 +35,7 @@ pub fn translate_module<'data>(
 
             Payload::TypeSection(types) => {
                 validator.type_section(&types)?;
-                parse_type_section(types, &mut module_translation_state, environ)?;
+                parse_type_section(types, environ)?;
             }
 
             Payload::ImportSection(imports) => {
@@ -127,5 +125,5 @@ pub fn translate_module<'data>(
         }
     }
 
-    Ok(module_translation_state)
+    Ok(())
 }

cranelift/wasm/src/sections_translator.rs

@@ -8,7 +8,6 @@
 //! is handled, according to the semantics of WebAssembly, to only specific expressions that are
 //! interpreted on the fly.
 use crate::environ::ModuleEnvironment;
-use crate::state::ModuleTranslationState;
 use crate::wasm_unsupported;
 use crate::{
     DataIndex, ElemIndex, FuncIndex, Global, GlobalIndex, GlobalInit, Memory, MemoryIndex, Table,
@@ -64,21 +63,15 @@ fn global(ty: GlobalType, initializer: GlobalInit) -> WasmResult<Global> {
 /// Parses the Type section of the wasm module.
 pub fn parse_type_section<'a>(
     types: TypeSectionReader<'a>,
-    module_translation_state: &mut ModuleTranslationState,
     environ: &mut dyn ModuleEnvironment<'a>,
 ) -> WasmResult<()> {
     let count = types.get_count();
-    module_translation_state.wasm_types.reserve(count as usize);
     environ.reserve_types(count)?;
 
     for entry in types {
         match entry? {
             Type::Func(wasm_func_ty) => {
                 environ.declare_type_func(wasm_func_ty.clone().try_into()?)?;
-                module_translation_state.wasm_types.push((
-                    wasm_func_ty.params().to_vec().into(),
-                    wasm_func_ty.results().to_vec().into(),
-                ));
             }
         }
     }

cranelift/wasm/src/state.rs

@@ -1,8 +1,5 @@
 //! WebAssembly module and function translation state.
 //!
-//! The `ModuleTranslationState` struct defined in this module is used to keep track of data about
-//! the whole WebAssembly module, such as the decoded type signatures.
-//!
 //! The `FuncTranslationState` struct defined in this module is used to keep track of the WebAssembly
 //! value and control stacks during the translation of a single function.
 

cranelift/wasm/src/state/mod.rs

@@ -1,14 +0,0 @@
-//! WebAssembly module and function translation state.
-//!
-//! The `ModuleTranslationState` struct defined in this module is used to keep track of data about
-//! the whole WebAssembly module, such as the decoded type signatures.
-//!
-//! The `FuncTranslationState` struct defined in this module is used to keep track of the WebAssembly
-//! value and control stacks during the translation of a single function.
-
-pub(crate) mod func_state;
-pub(crate) mod module_state;
-
-// Re-export for convenience.
-pub(crate) use func_state::*;
-pub(crate) use module_state::*;

cranelift/wasm/src/state/module_state.rs

@@ -1,31 +0,0 @@
-use crate::SignatureIndex;
-use cranelift_entity::PrimaryMap;
-use std::boxed::Box;
-
-/// Map of signatures to a function's parameter and return types.
-pub(crate) type WasmTypes =
-    PrimaryMap<SignatureIndex, (Box<[wasmparser::ValType]>, Box<[wasmparser::ValType]>)>;
-
-/// Contains information decoded from the Wasm module that must be referenced
-/// during each Wasm function's translation.
-///
-/// This is only for data that is maintained by `cranelift-wasm` itself, as
-/// opposed to being maintained by the embedder. Data that is maintained by the
-/// embedder is represented with `ModuleEnvironment`.
-#[derive(Debug)]
-pub struct ModuleTranslationState {
-    /// A map containing a Wasm module's original, raw signatures.
-    ///
-    /// This is used for translating multi-value Wasm blocks inside functions,
-    /// which are encoded to refer to their type signature via index.
-    pub(crate) wasm_types: WasmTypes,
-}
-
-impl ModuleTranslationState {
-    /// Creates a new empty ModuleTranslationState.
-    pub fn new() -> Self {
-        Self {
-            wasm_types: PrimaryMap::new(),
-        }
-    }
-}