diff --git a/lib/wasm/src/code_translator.rs b/lib/wasm/src/code_translator.rs index 751f528f63..48e689dbef 100644 --- a/lib/wasm/src/code_translator.rs +++ b/lib/wasm/src/code_translator.rs @@ -126,13 +126,27 @@ impl ControlStackFrame { /// Contains information passed along during the translation and that records: /// -/// - the depth of the two unreachable control blocks stacks, that are manipulated when translating +/// - The current value and control stacks. +/// - The depth of the two unreachable control blocks stacks, that are manipulated when translating /// unreachable code; struct TranslationState { + stack: Vec, + control_stack: Vec, phantom_unreachable_stack_depth: usize, real_unreachable_stack_depth: usize, } +impl TranslationState { + fn new() -> TranslationState { + TranslationState { + stack: Vec::new(), + control_stack: Vec::new(), + phantom_unreachable_stack_depth: 0, + real_unreachable_stack_depth: 0, + } + } +} + /// Holds mappings between the function and signatures indexes in the Wasm module and their /// references as imports of the Cretonne IL function. #[derive(Clone, Debug)] @@ -175,8 +189,6 @@ pub fn translate_function_body( } } let mut func_imports = FunctionImports::new(); - let mut stack: Vec = Vec::new(); - let mut control_stack: Vec = Vec::new(); // We introduce an arbitrary scope for the FunctionBuilder object { let mut builder = FunctionBuilder::new(&mut func, il_builder); @@ -206,13 +218,12 @@ pub fn translate_function_body( local_index += 1; } } - let mut state = TranslationState { - phantom_unreachable_stack_depth: 0, - real_unreachable_stack_depth: 0, - }; + + let mut state = TranslationState::new(); + // We initialize the control stack with the implicit function block let end_ebb = builder.create_ebb(); - control_stack.push(ControlStackFrame::Block { + state.control_stack.push(ControlStackFrame::Block { destination: end_ebb, original_stack_size: 0, return_values: sig.return_types @@ -231,20 +242,12 @@ pub fn translate_function_body( state.real_unreachable_stack_depth > 0 ); if state.real_unreachable_stack_depth > 0 { - translate_unreachable_operator( - op, - &mut builder, - &mut stack, - &mut control_stack, - &mut state, - ) + translate_unreachable_operator(op, &mut builder, &mut state) } else { translate_operator( op, &mut builder, runtime, - &mut stack, - &mut control_stack, &mut state, sig, functions, @@ -262,20 +265,22 @@ pub fn translate_function_body( // In WebAssembly, the final return instruction is implicit so we need to build it // explicitely in Cretonne IL. if !builder.is_filled() && (!builder.is_unreachable() || !builder.is_pristine()) { - let cut_index = stack.len() - sig.return_types.len(); - let return_vals = stack.split_off(cut_index); + let cut_index = state.stack.len() - sig.return_types.len(); + let return_vals = state.stack.split_off(cut_index); builder.ins().return_(&return_vals); } // Because the function has an implicit block as body, we need to explicitely close it. - let frame = control_stack.pop().unwrap(); + let frame = state.control_stack.pop().unwrap(); builder.switch_to_block(frame.following_code(), frame.return_values()); builder.seal_block(frame.following_code()); // If the block is reachable we also have to include a return instruction in it. if !builder.is_unreachable() { - stack.truncate(frame.original_stack_size()); - stack.extend_from_slice(builder.ebb_args(frame.following_code())); - let cut_index = stack.len() - sig.return_types.len(); - let return_vals = stack.split_off(cut_index); + state.stack.truncate(frame.original_stack_size()); + state.stack.extend_from_slice( + builder.ebb_args(frame.following_code()), + ); + let cut_index = state.stack.len() - sig.return_types.len(); + let return_vals = state.stack.split_off(cut_index); builder.ins().return_(&return_vals); } } @@ -288,8 +293,6 @@ fn translate_operator( op: &Operator, builder: &mut FunctionBuilder, runtime: &mut WasmRuntime, - stack: &mut Vec, - control_stack: &mut Vec, state: &mut TranslationState, sig: &Signature, functions: &[SignatureIndex], @@ -297,6 +300,9 @@ fn translate_operator( exports: &Option>, func_imports: &mut FunctionImports, ) { + let stack = &mut state.stack; + let control_stack = &mut state.control_stack; + // This big match treats all Wasm code operators. match *op { /********************************** Locals **************************************** @@ -1197,10 +1203,11 @@ fn translate_operator( fn translate_unreachable_operator( op: &Operator, builder: &mut FunctionBuilder, - stack: &mut Vec, - control_stack: &mut Vec, state: &mut TranslationState, ) { + let stack = &mut state.stack; + let control_stack = &mut state.control_stack; + // We don't translate because the code is unreachable // Nevertheless we have to record a phantom stack for this code // to know when the unreachable code ends