Method emit

crates/cpp/src/lib.rs:2451–3552

(
        &mut self,
        _resolve: &Resolve,
        inst: &wit_bindgen_core::abi::Instruction<'_>,
        operands: &mut Vec<Self::Operand>,
        results: &mut Vec<Self::Operand>,
    )

    type Operand = String;

    fn emit(
        &mut self,
        _resolve: &Resolve,
        inst: &wit_bindgen_core::abi::Instruction<'_>,
        operands: &mut Vec<Self::Operand>,
        results: &mut Vec<Self::Operand>,
    ) {
        let mut top_as = |cvt: &str| {
            results.push(format!("({cvt}({}))", operands.pop().unwrap()));
        };

        match inst {
            abi::Instruction::GetArg { nth } => {
                if *nth == 0 && self.params[0].as_str() == "self" {
                    if self.r#gen.in_guest_import {
                        results.push("(*this)".to_string());
                    } else {
                        results.push("(*lookup_resource(self))".to_string());
                    }
                } else {
                    results.push(self.params[*nth].clone());
                }
            }
            abi::Instruction::I32Const { val } => results.push(format!("(int32_t({val}))")),
            abi::Instruction::Bitcasts { casts } => {
                for (cast, op) in casts.iter().zip(operands) {
                    // let op = op;
                    results.push(self.r#gen.r#gen.perform_cast(op, cast));
                }
            }
            abi::Instruction::ConstZero { tys } => {
                for ty in tys.iter() {
                    match ty {
                        WasmType::I32 => results.push("int32_t(0)".to_string()),
                        WasmType::I64 => results.push("int64_t(0)".to_string()),
                        WasmType::F32 => results.push("0.0f".to_string()),
                        WasmType::F64 => results.push("0.0".to_string()),
                        WasmType::Length => results.push("size_t(0)".to_string()),
                        WasmType::Pointer => results.push("nullptr".to_string()),
                        WasmType::PointerOrI64 => results.push("int64_t(0)".to_string()),
                    }
                }
            }
            abi::Instruction::I32Load { offset } => {
                let tmp = self.tmp();
                uwriteln!(
                    self.src,
                    "int32_t l{tmp} = *((int32_t const*)({} + {offset}));",
                    operands[0],
                    offset = offset.format(POINTER_SIZE_EXPRESSION)
                );
                results.push(format!("l{tmp}"));
            }
            abi::Instruction::I32Load8U { offset } => {
                self.load_ext("uint8_t", *offset, operands, results)
            }
            abi::Instruction::I32Load8S { offset } => {
                self.load_ext("int8_t", *offset, operands, results)