Merge #360

360: Single-pass fixes and optimizations. r=syrusakbary a=losfair



Co-authored-by: losfair <zhy20000919@hotmail.com>
Co-authored-by: Lachlan Sneff <lachlan.sneff@gmail.com>

lib/singlepass-backend/src/codegen.rs

@@ -8,22 +8,40 @@ use wasmparser::{Operator, Type as WpType};
 
 pub trait ModuleCodeGenerator<FCG: FunctionCodeGenerator, RM: RunnableModule> {
     fn check_precondition(&mut self, module_info: &ModuleInfo) -> Result<(), CodegenError>;
+
+    /// Creates a new function and returns the function-scope code generator for it.
     fn next_function(&mut self) -> Result<&mut FCG, CodegenError>;
     fn finalize(self, module_info: &ModuleInfo) -> Result<RM, CodegenError>;
     fn feed_signatures(&mut self, signatures: Map<SigIndex, FuncSig>) -> Result<(), CodegenError>;
+
+    /// Sets function signatures.
     fn feed_function_signatures(
         &mut self,
         assoc: Map<FuncIndex, SigIndex>,
     ) -> Result<(), CodegenError>;
+
+    /// Adds an import function.
     fn feed_import_function(&mut self) -> Result<(), CodegenError>;
 }
 
+/// The function-scope code generator trait.
 pub trait FunctionCodeGenerator {
+    /// Sets the return type.
     fn feed_return(&mut self, ty: WpType) -> Result<(), CodegenError>;
+
+    /// Adds a parameter to the function.
     fn feed_param(&mut self, ty: WpType) -> Result<(), CodegenError>;
+
+    /// Adds `n` locals to the function.
     fn feed_local(&mut self, ty: WpType, n: usize) -> Result<(), CodegenError>;
+
+    /// Called before the first call to `feed_opcode`.
     fn begin_body(&mut self) -> Result<(), CodegenError>;
-    fn feed_opcode(&mut self, op: Operator, module_info: &ModuleInfo) -> Result<(), CodegenError>;
+
+    /// Called for each operator.
+    fn feed_opcode(&mut self, op: &Operator, module_info: &ModuleInfo) -> Result<(), CodegenError>;
+
+    /// Finalizes the function.
     fn finalize(&mut self) -> Result<(), CodegenError>;
 }