Function visit

crates/rustc_codegen_spirv/src/linker/simple_passes.rs:194–263

(
        sess: &Session,
        module: &'m Module,
        visited: &mut Vec<bool>,
        stack: &mut Vec<Word>,
        names: &mut Option<FxHashMap<Word, &'m str>>,
        index: usize,
      

    };

    fn visit<'m>(
        sess: &Session,
        module: &'m Module,
        visited: &mut Vec<bool>,
        stack: &mut Vec<Word>,
        names: &mut Option<FxHashMap<Word, &'m str>>,
        index: usize,
        func_id_to_idx: &FxHashMap<Word, usize>,
    ) -> Result<()> {
        if visited[index] {
            return Ok(());
        }
        visited[index] = true;
        stack.push(module.functions[index].def_id().unwrap());
        let mut any_err = None;
        for inst in module.functions[index].all_inst_iter() {
            if inst.class.opcode == Op::FunctionCall {
                let callee = func_id_to_idx[&inst.operands[0].unwrap_id_ref()];
                let callee_had_err =
                    visit(sess, module, visited, stack, names, callee, func_id_to_idx).err();
                any_err = any_err.or(callee_had_err);
            }
            if matches!(
                inst.class.opcode,
                Op::ImageSampleImplicitLod
                    | Op::ImageSampleDrefImplicitLod
                    | Op::ImageSampleProjImplicitLod
                    | Op::ImageSampleProjDrefImplicitLod
                    | Op::ImageQueryLod
                    | Op::ImageSparseSampleImplicitLod
                    | Op::ImageSparseSampleDrefImplicitLod
                    | Op::DPdx
                    | Op::DPdy
                    | Op::Fwidth
                    | Op::DPdxFine
                    | Op::DPdyFine
                    | Op::FwidthFine
                    | Op::DPdxCoarse
                    | Op::DPdyCoarse
                    | Op::FwidthCoarse
                    | Op::Kill
            ) {
                // These instructions are (usually) in system functions - if we get an error, allow
                // the system function to be visited again from elsewhere to emit another error
                // from another callsite.
                visited[index] = false;

                let names = names.get_or_insert_with(|| get_names(module));
                let stack = stack.iter().rev().map(|&s| get_name(names, s).into_owned());
                let note = once("Stack:".to_string())
                    .chain(stack)
                    .collect::<Vec<_>>()
                    .join("\n");
                any_err = Some(
                    sess.struct_err(format!(
                        "{} cannot be used outside a fragment shader",
                        inst.class.opname
                    ))