glsl_to_cxx/

lib.rs

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 #![allow(unknown_lints, mismatched_lifetime_syntaxes)]

extern crate glsl;

mod hir;

use glsl::parser::Parse;
use glsl::syntax;
use glsl::syntax::{TranslationUnit, UnaryOp};
use hir::{Statement, Type};
use std::cell::{Cell, RefCell};
use std::collections::{BTreeMap, HashMap};
use std::io::Read;
use std::mem;

#[derive(PartialEq, Eq)]
enum ShaderKind {
    Fragment,
    Vertex,
}

type UniformIndices = BTreeMap<String, (i32, hir::TypeKind, hir::StorageClass)>;

fn build_uniform_indices(indices: &mut UniformIndices, state: &hir::State) {
    for u in state.used_globals.borrow().iter() {
        let sym = state.sym(*u);
        match &sym.decl {
            hir::SymDecl::Global(storage, _, ty, _) => match storage {
                hir::StorageClass::Uniform | hir::StorageClass::Sampler(..) => {
                    let next_index = indices.len() as i32 + 1;
                    indices.entry(sym.name.clone()).or_insert((
                        next_index,
                        ty.kind.clone(),
                        *storage,
                    ));
                }
                _ => {}
            },
            _ => {}
        }
    }
}

pub fn translate(args: &mut dyn Iterator<Item = String>) -> String {
    let _cmd_name = args.next();
    let vertex_file = args.next().unwrap();

    let vs_name = std::path::Path::new(&vertex_file)
        .file_stem()
        .unwrap()
        .to_string_lossy()
        .to_string();

    let frag_file = args.next().unwrap();

    let fs_name = std::path::Path::new(&frag_file)
        .file_stem()
        .unwrap()
        .to_string_lossy()
        .to_string();

    let (vs_state, vs_hir, vs_is_frag) = parse_shader(vertex_file);
    let (fs_state, fs_hir, fs_is_frag) = parse_shader(frag_file);

    // we use a BTree so that iteration is stable
    let mut uniform_indices = BTreeMap::new();
    build_uniform_indices(&mut uniform_indices, &vs_state);
    build_uniform_indices(&mut uniform_indices, &fs_state);

    assert_eq!(fs_name, vs_name);

    let mut result = translate_shader(
        vs_name,
        vs_state,
        vs_hir,
        vs_is_frag,
        &uniform_indices,
    );
    result += "\n";
    result += &translate_shader(
        fs_name,
        fs_state,
        fs_hir,
        fs_is_frag,
        &uniform_indices,
    );
    result
}

fn parse_shader(file: String) -> (hir::State, hir::TranslationUnit, bool) {
    let mut contents = String::new();
    let is_frag = file.contains("frag");
    std::fs::File::open(&file)
        .unwrap()
        .read_to_string(&mut contents)
        .unwrap();
    let r = TranslationUnit::parse(contents);

    //println!("{:#?}", r);
    let mut ast_glsl = String::new();
    let r = match r {
        Ok(ok) => ok,
        Err(e) => panic!("failed to parse {:?}: {:?}", file, e),
    };
    glsl::transpiler::glsl::show_translation_unit(&mut ast_glsl, &r);
    //let mut fast = std::fs::File::create("ast").unwrap();
    //fast.write(ast_glsl.as_bytes());

    let mut state = hir::State::new();
    let hir = hir::ast_to_hir(&mut state, &r);
    (state, hir, is_frag)
}

fn translate_shader(
    name: String,
    mut state: hir::State,
    hir: hir::TranslationUnit,
    is_frag: bool,
    uniform_indices: &UniformIndices,
) -> String {
    //println!("{:#?}", state);

    hir::infer_run_class(&mut state, &hir);

    let mut uniforms = Vec::new();
    let mut inputs = Vec::new();
    let mut outputs = Vec::new();

    for i in &hir {
        match i {
            hir::ExternalDeclaration::Declaration(hir::Declaration::InitDeclaratorList(ref d)) => {
                match &state.sym(d.head.name).decl {
                    hir::SymDecl::Global(storage, ..)
                        if state.used_globals.borrow().contains(&d.head.name) =>
                    {
                        match storage {
                            hir::StorageClass::Uniform | hir::StorageClass::Sampler(..) => {
                                uniforms.push(d.head.name);
                            }
                            hir::StorageClass::In => {
                                inputs.push(d.head.name);
                            }
                            hir::StorageClass::Out | hir::StorageClass::FragColor(_) => {
                                outputs.push(d.head.name);
                            }
                            _ => {}
                        }
                    }
                    _ => {}
                }
            }
            _ => {}
        }
    }

    //println!("{:#?}", hir);

    let mut state = OutputState {
        hir: state,
        output: String::new(),
        buffer: RefCell::new(String::new()),
        indent: 0,
        should_indent: false,
        output_cxx: false,
        mask: None,
        cond_index: 0,
        return_type: None,
        return_declared: false,
        return_vector: false,
        is_scalar: Cell::new(false),
        is_lval: Cell::new(false),
        name: name.clone(),
        kind: if is_frag {
            ShaderKind::Fragment
        } else {
            ShaderKind::Vertex
        },
        functions: HashMap::new(),
        deps: RefCell::new(Vec::new()),
        vector_mask: 0,
        uses_discard: false,
        used_fragcoord: Cell::new(0),
        use_perspective: false,
        used_globals: RefCell::new(Vec::new()),
        texel_fetches: RefCell::new(Vec::new()),
    };

    show_translation_unit(&mut state, &hir);
    let _output_glsl = state.finish_output();

    state.should_indent = true;
    state.output_cxx = true;

    if state.output_cxx {
        let part_name = name.to_owned()
            + match state.kind {
                ShaderKind::Vertex => "_vert",
                ShaderKind::Fragment => "_frag",
            };

        if state.kind == ShaderKind::Vertex {
            write_common_globals(&mut state, &inputs, &outputs, uniform_indices);
            write!(state, "struct {0}_vert : VertexShaderImpl, {0}_common {{\nprivate:\n", name);
        } else {
            write!(state, "struct {0}_frag : FragmentShaderImpl, {0}_vert {{\nprivate:\n", name);
        }

        write!(state, "typedef {} Self;\n", part_name);

        show_translation_unit(&mut state, &hir);

        let pruned_inputs: Vec<_> = inputs
            .iter()
            .filter(|i| state.used_globals.borrow().contains(i))
            .cloned()
            .collect();

        if state.kind == ShaderKind::Vertex {
            write_set_uniform_1i(&mut state, uniform_indices);
            write_set_uniform_4fv(&mut state, uniform_indices);
            write_set_uniform_matrix4fv(&mut state, uniform_indices);
            write_load_attribs(&mut state, &pruned_inputs);
            write_store_outputs(&mut state, &outputs);
        } else {
            write_read_inputs(&mut state, &pruned_inputs);
        }

        write_abi(&mut state);
        write!(state, "}};\n\n");

        if state.kind == ShaderKind::Fragment {
            write!(state, "struct {0}_program : ProgramImpl, {0}_frag {{\n", name);
            write_get_uniform_index(&mut state, uniform_indices);
            write!(state, "void bind_attrib(const char* name, int index) override {{\n");
            write!(state, " attrib_locations.bind_loc(name, index);\n}}\n");
            write!(state, "int get_attrib(const char* name) const override {{\n");
            write!(state, " return attrib_locations.get_loc(name);\n}}\n");
            write!(state, "size_t interpolants_size() const override {{ return sizeof(InterpOutputs); }}\n");
            write!(state, "VertexShaderImpl* get_vertex_shader() override {{\n");
            write!(state, " return this;\n}}\n");
            write!(state, "FragmentShaderImpl* get_fragment_shader() override {{\n");
            write!(state, " return this;\n}}\n");
            write!(state, "const char* get_name() const override {{ return \"{}\"; }}\n", name);
            write!(state, "static ProgramImpl* loader() {{ return new {}_program; }}\n", name);
            write!(state, "}};\n\n");
        }

        define_global_consts(&mut state, &hir, &part_name);
    } else {
        show_translation_unit(&mut state, &hir);
    }
    let output_cxx = state.finish_output();

    //let mut hir = std::fs::File::create("hir").unwrap();
    //hir.write(output_glsl.as_bytes());

    output_cxx
}

fn write_get_uniform_index(state: &mut OutputState, uniform_indices: &UniformIndices) {
    write!(
        state,
        "int get_uniform(const char *name) const override {{\n"
    );
    for (uniform_name, (index, _, _)) in uniform_indices.iter() {
        write!(
            state,
            " if (strcmp(\"{}\", name) == 0) {{ return {}; }}\n",
            uniform_name, index
        );
    }
    write!(state, " return -1;\n");
    write!(state, "}}\n");
}

fn float4_compatible(ty: hir::TypeKind) -> bool {
    match ty {
        hir::TypeKind::Vec4 => true,
        _ => false,
    }
}

fn matrix4_compatible(ty: hir::TypeKind) -> bool {
    match ty {
        hir::TypeKind::Mat4 => true,
        _ => false,
    }
}

fn write_program_samplers(state: &mut OutputState, uniform_indices: &UniformIndices) {
    write!(state, "struct Samplers {{\n");
    for (name, (_, tk, storage)) in uniform_indices.iter() {
        match tk {
            hir::TypeKind::Sampler2D
            | hir::TypeKind::Sampler2DRect
            | hir::TypeKind::ISampler2D => {
                write!(state, " ");
                show_type_kind(state, &tk);
                let suffix = if let hir::StorageClass::Sampler(format) = storage {
                    format.type_suffix()
                } else {
                    None
                };
                write!(state, "{}_impl {}_impl;\n", suffix.unwrap_or(""), name);
                write!(state, " int {}_slot;\n", name);
            }
            _ => {}
        }
    }
    write!(
        state,
        " bool set_slot(int index, int value) {{\n"
    );
    write!(state, "  switch (index) {{\n");
    for (name, (index, tk, _)) in uniform_indices.iter() {
        match tk {
            hir::TypeKind::Sampler2D
            | hir::TypeKind::Sampler2DRect
            | hir::TypeKind::ISampler2D => {
                write!(state, "  case {}:\n", index);
                write!(state, "   {}_slot = value;\n", name);
                write!(state, "   return true;\n");
            }
            _ => {}
        }
    }
    write!(state, "  }}\n");
    write!(state, "  return false;\n");
    write!(state, " }}\n");
    write!(state, "}} samplers;\n");

}

fn write_bind_textures(state: &mut OutputState, uniforms: &UniformIndices) {
    write!(state, "void bind_textures() {{\n");
    for (name, (_, tk, storage)) in uniforms {
        match storage {
            hir::StorageClass::Sampler(_format) => {
                match tk {
                    hir::TypeKind::Sampler2D
                    | hir::TypeKind::Sampler2DRect => write!(state,
                        " {0} = lookup_sampler(&samplers.{0}_impl, samplers.{0}_slot);\n",
                        name),
                    hir::TypeKind::ISampler2D => write!(state,
                        " {0} = lookup_isampler(&samplers.{0}_impl, samplers.{0}_slot);\n",
                        name),
                    _ => {}
                };
            }
            _ => {}
        }
    }
    write!(state, "}}\n");
}

fn write_set_uniform_1i(
    state: &mut OutputState,
    uniforms: &UniformIndices,
) {
    write!(
        state,
        "static void set_uniform_1i(VertexShaderImpl* impl, int index, int value) {{\n"
    );
    write!(state, " Self* self = (Self*)impl;\n");
    write!(state, " if (self->samplers.set_slot(index, value)) return;\n");
    write!(state, " switch (index) {{\n");
    for (name, (index, tk, _)) in uniforms {
        write!(state, " case {}:\n", index);
        match tk {
            hir::TypeKind::Int => write!(
                state,
                "  self->{} = {}(value);\n",
                name,
                tk.cxx_primitive_scalar_type_name().unwrap(),
            ),
            _ => write!(state, "  assert(0); // {}\n", name),
        };
        write!(state, "  break;\n");
    }
    write!(state, " }}\n");
    write!(state, "}}\n");
}

fn write_set_uniform_4fv(
    state: &mut OutputState,
    uniforms: &UniformIndices,
) {
    write!(
        state,
        "static void set_uniform_4fv(VertexShaderImpl* impl, int index, const float *value) {{\n"
    );
    write!(state, " Self* self = (Self*)impl;\n");
    write!(state, " switch (index) {{\n");
    for (name, (index, tk, _)) in uniforms {
        write!(state, " case {}:\n", index);
        if float4_compatible(tk.clone()) {
            write!(
                state,
                "  self->{} = vec4_scalar::load_from_ptr(value);\n",
                name
            );
        } else {
            write!(state, "  assert(0); // {}\n", name);
        }
        write!(state, "  break;\n");
    }
    write!(state, " }}\n");
    write!(state, "}}\n");
}

fn write_set_uniform_matrix4fv(
    state: &mut OutputState,
    uniforms: &UniformIndices,
) {
    write!(
        state,
        "static void set_uniform_matrix4fv(VertexShaderImpl* impl, int index, const float *value) {{\n"
    );
    write!(state, " Self* self = (Self*)impl;\n");
    write!(state, " switch (index) {{\n");
    for (name, (index, tk, _)) in uniforms {
        write!(state, " case {}:\n", index);
        if matrix4_compatible(tk.clone()) {
            write!(
                state,
                "  self->{} = mat4_scalar::load_from_ptr(value);\n",
                name
            );
        } else {
            write!(state, "  assert(0); // {}\n", name);
        }
        write!(state, "  break;\n");
    }
    write!(state, " }}\n");
    write!(state, "}}\n");
}

fn write_bind_attrib_location(state: &mut OutputState, attribs: &[hir::SymRef]) {
    write!(state, "struct AttribLocations {{\n");
    for i in attribs {
        let sym = state.hir.sym(*i);
        write!(state, " int {} = NULL_ATTRIB;\n", sym.name.as_str());
    }
    write!(state, " void bind_loc(const char* name, int index) {{\n");
    for i in attribs {
        let sym = state.hir.sym(*i);
        write!(
            state,
            "  if (strcmp(\"{0}\", name) == 0) {{ {0} = index; return; }}\n",
            sym.name.as_str()
        );
    }
    write!(state, " }}\n");
    write!(state, " int get_loc(const char* name) const {{\n");
    for i in attribs {
        let sym = state.hir.sym(*i);
        write!(state,
            "  if (strcmp(\"{0}\", name) == 0) {{ \
                return {0} != NULL_ATTRIB ? {0} : -1; \
              }}\n",
            sym.name.as_str());
    }
    write!(state, "  return -1;\n");
    write!(state, " }}\n");
    write!(state, "}} attrib_locations;\n");
}

fn write_common_globals(state: &mut OutputState, attribs: &[hir::SymRef],
                        outputs: &[hir::SymRef], uniforms: &UniformIndices) {
    write!(state, "struct {}_common {{\n", state.name);

    write_program_samplers(state, uniforms);
    write_bind_attrib_location(state, attribs);

    let is_scalar = state.is_scalar.replace(true);
    for i in outputs {
        let sym = state.hir.sym(*i);
        match &sym.decl {
            hir::SymDecl::Global(hir::StorageClass::Out, _, ty, hir::RunClass::Scalar) => {
                show_type(state, ty);
                write!(state, " {};\n", sym.name.as_str());
            }
            _ => {}
        }
    }
    for (name, (_, tk, storage)) in uniforms {
        match storage {
            hir::StorageClass::Sampler(format) => {
                write!(state,
                       "{}{} {};\n",
                       tk.cxx_primitive_type_name().unwrap(),
                       format.type_suffix().unwrap_or(""),
                       name,
                );
            }
            _ => {
                show_type_kind(state, tk);
                write!(state, " {};\n", name);
            }
        }
    }
    state.is_scalar.set(is_scalar);

    write_bind_textures(state, uniforms);

    write!(state, "}};\n");
}

//fn type_name(state: &OutputState, ty: &Type) -> String {
//  let buffer = state.push_buffer();
//  show_type(state, ty);
//  state.pop_buffer(buffer)
//}

fn write_load_attribs(state: &mut OutputState, attribs: &[hir::SymRef]) {
    write!(state, "static void load_attribs(\
                   VertexShaderImpl* impl, VertexAttrib *attribs, \
                   uint32_t start, int instance, int count) {{\
                     Self* self = (Self*)impl;\n");
    for i in attribs {
        let sym = state.hir.sym(*i);
        match &sym.decl {
            hir::SymDecl::Global(_, _interpolation, _ty, run_class) => {
                let name = sym.name.as_str();
                let func = if *run_class == hir::RunClass::Scalar {
                    "load_flat_attrib"
                } else {
                    "load_attrib"
                };
                write!(state,
                    " {0}(self->{1}, attribs[self->attrib_locations.{1}], start, instance, count);\n",
                    func, name);
            }
            _ => panic!(),
        }
    }
    write!(state, "}}\n");
}

fn write_store_outputs(state: &mut OutputState, outputs: &[hir::SymRef]) {
    let is_scalar = state.is_scalar.replace(true);
    write!(state, "public:\nstruct InterpOutputs {{\n");
    if state.hir.used_clip_dist != 0 {
       state.write(" Float swgl_ClipDistance;\n");
    }
    for i in outputs {
        let sym = state.hir.sym(*i);
        match &sym.decl {
            hir::SymDecl::Global(_, _, ty, run_class) => {
                if *run_class != hir::RunClass::Scalar {
                    show_type(state, ty);
                    write!(state, " {};\n", sym.name.as_str());
                }
            }
            _ => panic!(),
        }
    }

    write!(state, "}};\nprivate:\n");
    state.is_scalar.set(is_scalar);

    write!(
        state,
        "ALWAYS_INLINE void store_interp_outputs(char* dest_ptr, size_t stride) {{\n"
    );
    write!(state, "  for(int n = 0; n < 4; n++) {{\n");
    write!(
        state,
        "    auto* dest = reinterpret_cast<InterpOutputs*>(dest_ptr);\n"
    );
    if state.hir.used_clip_dist != 0 {
        for (i, comp) in "xyzw".chars().enumerate() {
            if (state.hir.used_clip_dist & (1 << i)) != 0 {
                write!(state, "    dest->swgl_ClipDistance.{} = get_nth(gl_ClipDistance[{}], n);\n", comp, i);
            } else {
                write!(state, "    dest->swgl_ClipDistance.{} = 0.0f;\n", comp);
            }
        }
    }
    for i in outputs {
        let sym = state.hir.sym(*i);
        match &sym.decl {
            hir::SymDecl::Global(_, _, _, run_class) => {
                if *run_class != hir::RunClass::Scalar {
                    let name = sym.name.as_str();
                    write!(state, "    dest->{} = get_nth({}, n);\n", name, name);
                }
            }
            _ => panic!(),
        }
    }
    write!(state, "    dest_ptr += stride;\n");
    write!(state, "  }}\n");
    write!(state, "}}\n");
}

fn write_read_inputs(state: &mut OutputState, inputs: &[hir::SymRef]) {
    write!(
        state,
        "typedef {}_vert::InterpOutputs InterpInputs;\n",
        state.name
    );

    write!(state, "InterpInputs interp_step;\n");

    let mut has_varying = false;
    for i in inputs {
        let sym = state.hir.sym(*i);
        match &sym.decl {
            hir::SymDecl::Global(_, _, ty, run_class) => {
                if *run_class != hir::RunClass::Scalar {
                    if !has_varying {
                        has_varying = true;
                        write!(state, "struct InterpPerspective {{\n");
                    }
                    show_type(state, ty);
                    write!(state, " {};\n", sym.name.as_str());
                }
            }
            _ => panic!(),
        }
    }
    if has_varying {
        write!(state, "}};\n");
        write!(state, "InterpPerspective interp_perspective;\n");
    }

    write!(state,
        "static void read_interp_inputs(\
            FragmentShaderImpl* impl, const void* init_, const void* step_) {{\
            Self* self = (Self*)impl;\
            const InterpInputs* init = (const InterpInputs*)init_;\
            const InterpInputs* step = (const InterpInputs*)step_;\n");
    for i in inputs {
        let sym = state.hir.sym(*i);
        match &sym.decl {
            hir::SymDecl::Global(_, _, _, run_class) => {
                if *run_class != hir::RunClass::Scalar {
                    let name = sym.name.as_str();
                    write!(
                        state,
                        "  self->{0} = init_interp(init->{0}, step->{0});\n",
                        name
                    );
                    write!(
                        state,
                        "  self->interp_step.{0} = step->{0} * 4.0f;\n",
                        name
                    );
                }
            }
            _ => panic!(),
        }
    }
    write!(state, "}}\n");

    let used_fragcoord = state.used_fragcoord.get();
    if has_varying || (used_fragcoord & (4 | 8)) != 0 {
        state.use_perspective = true;
    }
    if state.use_perspective {
        write!(state,
            "static void read_perspective_inputs(\
                FragmentShaderImpl* impl, const void* init_, const void* step_) {{\
                Self* self = (Self*)impl;\
                const InterpInputs* init = (const InterpInputs*)init_;\
                const InterpInputs* step = (const InterpInputs*)step_;\n");
        if has_varying {
            write!(state, "  Float w = 1.0f / self->gl_FragCoord.w;\n");
        }
        for i in inputs {
            let sym = state.hir.sym(*i);
            match &sym.decl {
                hir::SymDecl::Global(_, _, _, run_class) => {
                    if *run_class != hir::RunClass::Scalar {
                        let name = sym.name.as_str();
                        write!(
                            state,
                            "  self->interp_perspective.{0} = init_interp(init->{0}, step->{0});\n",
                            name
                        );
                        write!(state, "  self->{0} = self->interp_perspective.{0} * w;\n", name);
                        write!(
                            state,
                            "  self->interp_step.{0} = step->{0} * 4.0f;\n",
                            name
                        );
                    }
                }
                _ => panic!(),
            }
        }
        write!(state, "}}\n");
    }

    write!(state, "ALWAYS_INLINE void step_interp_inputs(int steps = 4) {{\n");
    if (used_fragcoord & 1) != 0 {
        write!(state, "  step_fragcoord(steps);\n");
    }
    if !inputs.is_empty() {
        write!(state, "  float chunks = steps * 0.25f;\n");
    }
    for i in inputs {
        let sym = state.hir.sym(*i);
        match &sym.decl {
            hir::SymDecl::Global(_, _, _, run_class) => {
                if *run_class != hir::RunClass::Scalar {
                    let name = sym.name.as_str();
                    write!(state, "  {0} += interp_step.{0} * chunks;\n", name);
                }
            }
            _ => panic!(),
        }
    }
    write!(state, "}}\n");

    if state.use_perspective {
        write!(state, "ALWAYS_INLINE void step_perspective_inputs(int steps = 4) {{\n");
        if (used_fragcoord & 1) != 0 {
            write!(state, "  step_fragcoord(steps);\n");
        }
        write!(state, "  step_perspective(steps);\n");
        if !inputs.is_empty() {
            write!(state, "  float chunks = steps * 0.25f;\n");
        }
        if has_varying {
            write!(state, "  Float w = 1.0f / gl_FragCoord.w;\n");
        }
        for i in inputs {
            let sym = state.hir.sym(*i);
            match &sym.decl {
                hir::SymDecl::Global(_, _, _, run_class) => {
                    if *run_class != hir::RunClass::Scalar {
                        let name = sym.name.as_str();
                        write!(state, "  interp_perspective.{0} += interp_step.{0} * chunks;\n", name);
                        write!(state, "  {0} = w * interp_perspective.{0};\n", name);
                    }
                }
                _ => panic!(),
            }
        }
        write!(state, "}}\n");
    }
}

pub struct OutputState {
    hir: hir::State,
    output: String,
    buffer: RefCell<String>,
    should_indent: bool,
    output_cxx: bool,
    indent: i32,
    mask: Option<Box<hir::Expr>>,
    cond_index: usize,
    return_type: Option<Box<hir::Type>>,
    return_declared: bool,
    return_vector: bool,
    is_scalar: Cell<bool>,
    is_lval: Cell<bool>,
    name: String,
    kind: ShaderKind,
    functions: HashMap<(hir::SymRef, u32), bool>,
    deps: RefCell<Vec<(hir::SymRef, u32)>>,
    vector_mask: u32,
    uses_discard: bool,
    used_fragcoord: Cell<i32>,
    use_perspective: bool,
    used_globals: RefCell<Vec<hir::SymRef>>,
    texel_fetches: RefCell<Vec<(hir::SymRef, hir::SymRef, hir::TexelFetchOffsets)>>,
}

use std::fmt::{Arguments, Write};

impl OutputState {
    fn indent(&mut self) {
        if self.should_indent {
            self.indent += 1
        }
    }
    fn outdent(&mut self) {
        if self.should_indent {
            self.indent -= 1
        }
    }

    fn write(&self, s: &str) {
        self.buffer.borrow_mut().push_str(s);
    }

    fn flush_buffer(&mut self) {
        self.output.push_str(&self.buffer.borrow());
        self.buffer.borrow_mut().clear();
    }

    fn finish_output(&mut self) -> String {
        self.flush_buffer();

        let mut s = String::new();
        mem::swap(&mut self.output, &mut s);
        s
    }

    fn push_buffer(&self) -> String {
        self.buffer.replace(String::new())
    }

    fn pop_buffer(&self, s: String) -> String {
        self.buffer.replace(s)
    }

    fn write_fmt(&self, args: Arguments) {
        let _ = self.buffer.borrow_mut().write_fmt(args);
    }
}

pub fn show_identifier(state: &OutputState, i: &syntax::Identifier) {
    state.write(&i.0);
}

fn glsl_primitive_type_name_to_cxx(glsl_name: &str) -> &str {
    hir::TypeKind::from_glsl_primitive_type_name(glsl_name)
        .and_then(|kind| kind.cxx_primitive_type_name())
        .unwrap_or(glsl_name)
}

fn add_used_global(state: &OutputState, i: &hir::SymRef) {
    let mut globals = state.used_globals.borrow_mut();
    if !globals.contains(i) {
        globals.push(*i);
    }
}

pub fn show_sym(state: &OutputState, i: &hir::SymRef) {
    let sym = state.hir.sym(*i);
    match &sym.decl {
        hir::SymDecl::NativeFunction(_, ref cxx_name, _) => {
            let mut name = sym.name.as_str();
            if state.output_cxx {
                name = cxx_name.unwrap_or(name);
            }
            state.write(name);
        }
        hir::SymDecl::Global(..) => {
            if state.output_cxx {
                add_used_global(state, i);
            }
            let mut name = sym.name.as_str();
            if state.output_cxx {
                name = glsl_primitive_type_name_to_cxx(name);
            }
            state.write(name);
        }
        hir::SymDecl::UserFunction(..) | hir::SymDecl::Local(..) | hir::SymDecl::Struct(..) => {
            let mut name = sym.name.as_str();
            // we want to replace constructor names
            if state.output_cxx {
                name = glsl_primitive_type_name_to_cxx(name);
            }
            state.write(name);
        }
    }
}

pub fn show_variable(state: &OutputState, i: &hir::SymRef) {
    let sym = state.hir.sym(*i);
    match &sym.decl {
        hir::SymDecl::Global(_, _, ty, _) => {
            show_type(state, ty);
            state.write(" ");
            let mut name = sym.name.as_str();
            if state.output_cxx {
                name = glsl_primitive_type_name_to_cxx(name);
            }
            state.write(name);
        }
        _ => panic!(),
    }
}

pub fn write_default_constructor(state: &OutputState, name: &str) {
    // write default constructor
    let _ = write!(state, "{}() = default;\n", name);
}

pub fn write_constructor(state: &OutputState, name: &str, s: &hir::StructFields) {
    if s.fields.len() == 1 {
        state.write("explicit ");
    }
    let _ = write!(state, "{}(", name);
    let mut first_field = true;
    for field in &s.fields {
        if !first_field {
            state.write(", ");
        }
        show_type(state, &field.ty);
        state.write(" ");
        show_identifier_and_type(state, &field.name, &field.ty);
        first_field = false;
    }
    state.write(") : ");

    let mut first_field = true;
    for field in &s.fields {
        if !first_field {
            state.write(", ");
        }
        let _ = write!(state, "{}({})", field.name, field.name);
        first_field = false;
    }
    state.write("{}\n");
}

pub fn write_convert_constructor(state: &OutputState, name: &str, s: &hir::StructFields) {
    if s.fields.len() == 1 {
        state.write("explicit ");
    }
    let _ = write!(state, "{}(", name);
    let mut first_field = true;
    for field in &s.fields {
        if !first_field {
            state.write(", ");
        }

        let is_scalar = state.is_scalar.replace(true);
        show_type(state, &field.ty);
        state.is_scalar.set(is_scalar);

        state.write(" ");

        show_identifier_and_type(state, &field.name, &field.ty);
        first_field = false;
    }
    state.write(")");

    let mut first_field = true;
    for hir::StructField { ty, name } in &s.fields {
        if ty.array_sizes.is_none() {
            if first_field {
                state.write(":");
            } else {
                state.write(",");
            }
            let _ = write!(state, "{}({})", name, name);
            first_field = false;
        }
    }
    state.write("{\n");
    for hir::StructField { ty, name } in &s.fields {
        if ty.array_sizes.is_some() {
            let _ = write!(state, "this->{}.convert({});\n", name, name);
        }
    }
    state.write("}\n");

    let _ = write!(state, "IMPLICIT {}({}_scalar s)", name, name);
    let mut first_field = true;
    for hir::StructField { ty, name } in &s.fields {
        if ty.array_sizes.is_none() {
            if first_field {
                state.write(":");
            } else {
                state.write(",");
            }
            let _ = write!(state, "{}(s.{})", name, name);
            first_field = false;
        }
    }
    state.write("{\n");
    for hir::StructField { ty, name } in &s.fields {
        if ty.array_sizes.is_some() {
            let _ = write!(state, "{}.convert(s.{});\n", name, name);
        }
    }
    state.write("}\n");
}

pub fn write_if_then_else(state: &OutputState, name: &str, s: &hir::StructFields) {
    let _ = write!(
        state,
        "friend {} if_then_else(I32 c, {} t, {} e) {{ return {}(\n",
        name, name, name, name
    );
    let mut first_field = true;
    for field in &s.fields {
        if !first_field {
            state.write(", ");
        }
        let _ = write!(state, "if_then_else(c, t.{}, e.{})", field.name, field.name);
        first_field = false;
    }
    state.write(");\n}");
}

pub fn show_storage_class(state: &OutputState, q: &hir::StorageClass) {
    match *q {
        hir::StorageClass::None => {}
        hir::StorageClass::Const => {
            state.write("const ");
        }
        hir::StorageClass::In => {
            state.write("in ");
        }
        hir::StorageClass::Out => {
            state.write("out ");
        }
        hir::StorageClass::FragColor(index) => {
            write!(state, "layout(location = 0, index = {}) out ", index);
        }
        hir::StorageClass::Uniform | hir::StorageClass::Sampler(..) => {
            state.write("uniform ");
        }
    }
}

pub fn show_sym_decl(state: &OutputState, i: &hir::SymRef) {
    let sym = state.hir.sym(*i);
    match &sym.decl {
        hir::SymDecl::Global(storage, ..) => {
            if !state.output_cxx {
                show_storage_class(state, storage)
            }
            if storage == &hir::StorageClass::Const {
                state.write("static constexpr ");
            }
            let mut name = sym.name.as_str();
            if state.output_cxx {
                name = glsl_primitive_type_name_to_cxx(name);
            }
            state.write(name);
        }
        hir::SymDecl::Local(storage, ..) => {
            if !state.output_cxx {
                show_storage_class(state, storage)
            }
            if storage == &hir::StorageClass::Const {
                state.write("const ");
            }
            let mut name = sym.name.as_str();
            if state.output_cxx {
                name = glsl_primitive_type_name_to_cxx(name);
            }
            state.write(name);
        }
        hir::SymDecl::Struct(s) => {
            let name = sym.name.as_str();

            if state.output_cxx {
                let name_scalar = format!("{}_scalar", name);
                write!(state, "struct {} {{\n", name_scalar);
                let is_scalar = state.is_scalar.replace(true);
                for field in &s.fields {
                    show_struct_field(state, field);
                }
                write_default_constructor(state, &name_scalar);
                write_constructor(state, &name_scalar, s);
                state.is_scalar.set(is_scalar);
                state.write("};\n");
            }

            write!(state, "struct {} {{\n", name);
            for field in &s.fields {
                show_struct_field(state, field);
            }

            // write if_then_else
            if state.output_cxx {
                write_default_constructor(state, name);
                write_constructor(state, name, s);
                write_convert_constructor(state, name, s);
                write_if_then_else(state, name, s);
            }
            state.write("}");
        }
        _ => panic!(),
    }
}

pub fn show_type_name(state: &OutputState, t: &syntax::TypeName) {
    state.write(&t.0);
}

pub fn show_type_specifier_non_array(state: &mut OutputState, t: &syntax::TypeSpecifierNonArray) {
    if let Some(kind) = hir::TypeKind::from_primitive_type_specifier(t) {
        show_type_kind(state, &kind);
    } else {
        match t {
            syntax::TypeSpecifierNonArray::Struct(ref _s) => panic!(), //show_struct_non_declaration(state, s),
            syntax::TypeSpecifierNonArray::TypeName(ref tn) => show_type_name(state, tn),
            _ => unreachable!(),
        }
    }
}

pub fn show_type_kind(state: &OutputState, t: &hir::TypeKind) {
    if state.output_cxx {
        if state.is_scalar.get() {
            if let Some(name) = t.cxx_primitive_scalar_type_name() {
                state.write(name);
            } else if let Some(name) = t.cxx_primitive_type_name() {
                let mut scalar_name = String::from(name);
                scalar_name.push_str("_scalar");
                state.write(scalar_name.as_str());
            } else {
                match t {
                    hir::TypeKind::Struct(ref s) => {
                        let mut scalar_name = String::from(state.hir.sym(*s).name.as_str());
                        scalar_name.push_str("_scalar");
                        state.write(scalar_name.as_str());
                    }
                    _ => unreachable!(),
                }
            }
        } else if let Some(name) = t.cxx_primitive_type_name() {
            state.write(name);
        } else {
            match t {
                hir::TypeKind::Struct(ref s) => {
                    state.write(state.hir.sym(*s).name.as_str());
                }
                _ => unreachable!(),
            }
        }
    } else if let Some(name) = t.glsl_primitive_type_name() {
        state.write(name);
    } else {
        match t {
            hir::TypeKind::Struct(ref s) => {
                state.write(state.hir.sym(*s).name.as_str());
            }
            _ => unreachable!(),
        }
    }
}

pub fn show_type_specifier(state: &mut OutputState, t: &syntax::TypeSpecifier) {
    show_type_specifier_non_array(state, &t.ty);

    if let Some(ref arr_spec) = t.array_specifier {
        show_array_spec(state, arr_spec);
    }
}

pub fn show_type(state: &OutputState, t: &Type) {
    if !state.output_cxx {
        if let Some(ref precision) = t.precision {
            show_precision_qualifier(state, precision);
            state.write(" ");
        }
    }

    if state.output_cxx {
        if let Some(ref array) = t.array_sizes {
            state.write("Array<");
            show_type_kind(state, &t.kind);
            let size = match &array.sizes[..] {
                [size] => size,
                _ => panic!(),
            };
            state.write(",");
            show_hir_expr(state, size);
            state.write(">");
        } else {
            show_type_kind(state, &t.kind);
        }
    } else {
        show_type_kind(state, &t.kind);
    }

    /*if let Some(ref arr_spec) = t.array_sizes {
      panic!();
    }*/
}

/*pub fn show_fully_specified_type(state: &mut OutputState, t: &FullySpecifiedType) {
  state.flat = false;
  if let Some(ref qual) = t.qualifier {
    if !state.output_cxx {
      show_type_qualifier(state, &qual);
    } else {
      state.flat =
        qual.qualifiers.0.iter()
            .flat_map(|q| match q { syntax::TypeQualifierSpec::Interpolation(Flat) => Some(()), _ => None})
            .next().is_some();
    }
    state.write(" ");
  }

  show_type_specifier(state, &t.ty);
}*/

/*pub fn show_struct_non_declaration(state: &mut OutputState, s: &syntax::StructSpecifier) {
  state.write("struct ");

  if let Some(ref name) = s.name {
    let _ = write!(state, "{} ", name);
  }

  state.write("{\n");

  for field in &s.fields.0 {
    show_struct_field(state, field);
  }

  state.write("}");
}*/

pub fn show_struct(_state: &OutputState, _s: &syntax::StructSpecifier) {
    panic!();
    //show_struct_non_declaration(state, s);
    //state.write(";\n");
}

pub fn show_struct_field(state: &OutputState, field: &hir::StructField) {
    show_type(state, &field.ty);
    state.write(" ");

    show_identifier_and_type(state, &field.name, &field.ty);

    state.write(";\n");
}

pub fn show_array_spec(state: &OutputState, a: &syntax::ArraySpecifier) {
    for dimension in &a.dimensions {
        match dimension {
            syntax::ArraySpecifierDimension::Unsized => {
                state.write("[]");
            }
            syntax::ArraySpecifierDimension::ExplicitlySized(ref e) => {
                state.write("[");
                show_expr(state, &e);
                state.write("]");
            }
        }
    }
}

pub fn show_identifier_and_type(state: &OutputState, ident: &syntax::Identifier, ty: &hir::Type) {
    let _ = write!(state, "{}", ident);

    if !state.output_cxx {
        if let Some(ref arr_spec) = ty.array_sizes {
            show_array_sizes(state, &arr_spec);
        }
    }
}

pub fn show_arrayed_identifier(state: &OutputState, ident: &syntax::ArrayedIdentifier) {
    let _ = write!(state, "{}", ident.ident);

    if let Some(ref arr_spec) = ident.array_spec {
        show_array_spec(state, &arr_spec);
    }
}

pub fn show_array_sizes(state: &OutputState, a: &hir::ArraySizes) {
    state.write("[");
    match &a.sizes[..] {
        [a] => show_hir_expr(state, a),
        _ => panic!(),
    }

    state.write("]");
    /*
    match *a {
      syntax::ArraySpecifier::Unsized => { state.write("[]"); }
      syntax::ArraySpecifier::ExplicitlySized(ref e) => {
        state.write("[");
        show_expr(state, &e);
        state.write("]");
      }
    }*/
}

pub fn show_type_qualifier(state: &OutputState, q: &hir::TypeQualifier) {
    let mut qualifiers = q.qualifiers.0.iter();
    let first = qualifiers.next().unwrap();

    show_type_qualifier_spec(state, first);

    for qual_spec in qualifiers {
        state.write(" ");
        show_type_qualifier_spec(state, qual_spec)
    }
}

pub fn show_type_qualifier_spec(state: &OutputState, q: &hir::TypeQualifierSpec) {
    match *q {
        hir::TypeQualifierSpec::Layout(ref l) => show_layout_qualifier(state, &l),
        hir::TypeQualifierSpec::Parameter(ref _p) => panic!(),
        hir::TypeQualifierSpec::Memory(ref _m) => panic!(),
        hir::TypeQualifierSpec::Invariant => {
            state.write("invariant");
        }
        hir::TypeQualifierSpec::Precise => {
            state.write("precise");
        }
    }
}

pub fn show_syntax_storage_qualifier(state: &OutputState, q: &syntax::StorageQualifier) {
    match *q {
        syntax::StorageQualifier::Const => {
            state.write("const");
        }
        syntax::StorageQualifier::InOut => {
            state.write("inout");
        }
        syntax::StorageQualifier::In => {
            state.write("in");
        }
        syntax::StorageQualifier::Out => {
            state.write("out");
        }
        syntax::StorageQualifier::Centroid => {
            state.write("centroid");
        }
        syntax::StorageQualifier::Patch => {
            state.write("patch");
        }
        syntax::StorageQualifier::Sample => {
            state.write("sample");
        }
        syntax::StorageQualifier::Uniform => {
            state.write("uniform");
        }
        syntax::StorageQualifier::Attribute => {
            state.write("attribute");
        }
        syntax::StorageQualifier::Varying => {
            state.write("varying");
        }
        syntax::StorageQualifier::Buffer => {
            state.write("buffer");
        }
        syntax::StorageQualifier::Shared => {
            state.write("shared");
        }
        syntax::StorageQualifier::Coherent => {
            state.write("coherent");
        }
        syntax::StorageQualifier::Volatile => {
            state.write("volatile");
        }
        syntax::StorageQualifier::Restrict => {
            state.write("restrict");
        }
        syntax::StorageQualifier::ReadOnly => {
            state.write("readonly");
        }
        syntax::StorageQualifier::WriteOnly => {
            state.write("writeonly");
        }
        syntax::StorageQualifier::Subroutine(ref n) => show_subroutine(state, &n),
    }
}

pub fn show_subroutine(state: &OutputState, types: &[syntax::TypeName]) {
    state.write("subroutine");

    if !types.is_empty() {
        state.write("(");

        let mut types_iter = types.iter();
        let first = types_iter.next().unwrap();

        show_type_name(state, first);

        for type_name in types_iter {
            state.write(", ");
            show_type_name(state, type_name);
        }

        state.write(")");
    }
}

pub fn show_layout_qualifier(state: &OutputState, l: &syntax::LayoutQualifier) {
    let mut qualifiers = l.ids.0.iter();
    let first = qualifiers.next().unwrap();

    state.write("layout (");
    show_layout_qualifier_spec(state, first);

    for qual_spec in qualifiers {
        state.write(", ");
        show_layout_qualifier_spec(state, qual_spec);
    }

    state.write(")");
}

pub fn show_layout_qualifier_spec(state: &OutputState, l: &syntax::LayoutQualifierSpec) {
    match *l {
        syntax::LayoutQualifierSpec::Identifier(ref i, Some(ref e)) => {
            let _ = write!(state, "{} = ", i);
            show_expr(state, &e);
        }
        syntax::LayoutQualifierSpec::Identifier(ref i, None) => show_identifier(state, &i),
        syntax::LayoutQualifierSpec::Shared => {
            state.write("shared");
        }
    }
}

pub fn show_precision_qualifier(state: &OutputState, p: &syntax::PrecisionQualifier) {
    match *p {
        syntax::PrecisionQualifier::High => {
            state.write("highp");
        }
        syntax::PrecisionQualifier::Medium => {
            state.write("mediump");
        }
        syntax::PrecisionQualifier::Low => {
            state.write("low");
        }
    }
}

pub fn show_interpolation_qualifier(state: &OutputState, i: &syntax::InterpolationQualifier) {
    match *i {
        syntax::InterpolationQualifier::Smooth => {
            state.write("smooth");
        }
        syntax::InterpolationQualifier::Flat => {
            state.write("flat");
        }
        syntax::InterpolationQualifier::NoPerspective => {
            state.write("noperspective");
        }
    }
}

pub fn show_parameter_qualifier(state: &mut OutputState, i: &Option<hir::ParameterQualifier>) {
    if let Some(i) = i {
        if state.output_cxx {
            match *i {
                hir::ParameterQualifier::Out => {
                    state.write("&");
                }
                hir::ParameterQualifier::InOut => {
                    state.write("&");
                }
                _ => {}
            }
        } else {
            match *i {
                hir::ParameterQualifier::Const => {
                    state.write("const");
                }
                hir::ParameterQualifier::In => {
                    state.write("in");
                }
                hir::ParameterQualifier::Out => {
                    state.write("out");
                }
                hir::ParameterQualifier::InOut => {
                    state.write("inout");
                }
            }
        }
    }
}

pub fn show_float(state: &OutputState, x: f32) {
    if x.fract() == 0. {
        write!(state, "{}.f", x);
    } else {
        write!(state, "{}f", x);
    }
}

pub fn show_double(state: &OutputState, x: f64) {
    // force doubles to print as floats
    if x.fract() == 0. {
        write!(state, "{}.f", x);
    } else {
        write!(state, "{}f", x);
    }
}

fn expr_run_class(state: &OutputState, expr: &hir::Expr) -> hir::RunClass {
    match &expr.kind {
        hir::ExprKind::Variable(i) => symbol_run_class(&state.hir.sym(*i).decl, state.vector_mask),
        hir::ExprKind::IntConst(_)
        | hir::ExprKind::UIntConst(_)
        | hir::ExprKind::BoolConst(_)
        | hir::ExprKind::FloatConst(_)
        | hir::ExprKind::DoubleConst(_) => hir::RunClass::Scalar,
        hir::ExprKind::Unary(_, ref e) => expr_run_class(state, e),
        hir::ExprKind::Binary(_, ref l, ref r) => {
            expr_run_class(state, l).merge(expr_run_class(state, r))
        }
        hir::ExprKind::Ternary(ref c, ref s, ref e) => expr_run_class(state, c)
            .merge(expr_run_class(state, s))
            .merge(expr_run_class(state, e)),
        hir::ExprKind::Assignment(ref v, _, ref e) => {
            expr_run_class(state, v).merge(expr_run_class(state, e))
        }
        hir::ExprKind::Bracket(ref e, ref indx) => {
            indx.iter().fold(
                expr_run_class(state, e),
                |run_class, indx| run_class.merge(expr_run_class(state, indx)),
            )
        }
        hir::ExprKind::FunCall(ref fun, ref args) => {
            let arg_mask: u32 = args.iter().enumerate().fold(0, |mask, (idx, e)| {
                if expr_run_class(state, e) == hir::RunClass::Vector {
                    mask | (1 << idx)
                } else {
                    mask
                }
            });
            match fun {
                hir::FunIdentifier::Identifier(ref sym) => match &state.hir.sym(*sym).decl {
                    hir::SymDecl::NativeFunction(_, _, ref ret_class) => {
                        if *ret_class != hir::RunClass::Unknown {
                            *ret_class
                        } else if arg_mask != 0 {
                            hir::RunClass::Vector
                        } else {
                            hir::RunClass::Scalar
                        }
                    }
                    hir::SymDecl::UserFunction(ref fd, ref run_class) => {
                        let param_mask: u32 = fd.prototype.parameters.iter().enumerate().fold(
                            arg_mask,
                            |mask, (idx, param)| {
                                if let hir::FunctionParameterDeclaration::Named(Some(qual), p) =
                                    param
                                {
                                    match qual {
                                        hir::ParameterQualifier::InOut
                                        | hir::ParameterQualifier::Out => {
                                            if symbol_run_class(
                                                &state.hir.sym(p.sym).decl,
                                                arg_mask,
                                            ) == hir::RunClass::Vector
                                            {
                                                mask | (1 << idx)
                                            } else {
                                                mask
                                            }
                                        }
                                        _ => mask,
                                    }
                                } else {
                                    mask
                                }
                            },
                        );
                        match *run_class {
                            hir::RunClass::Scalar => hir::RunClass::Scalar,
                            hir::RunClass::Dependent(mask) => {
                                if (mask & param_mask) != 0 {
                                    hir::RunClass::Vector
                                } else {
                                    hir::RunClass::Scalar
                                }
                            }
                            _ => hir::RunClass::Vector,
                        }
                    }
                    hir::SymDecl::Struct(..) => {
                        if arg_mask != 0 {
                            hir::RunClass::Vector
                        } else {
                            hir::RunClass::Scalar
                        }
                    }
                    _ => panic!(),
                },
                hir::FunIdentifier::Constructor(..) => {
                    if arg_mask != 0 {
                        hir::RunClass::Vector
                    } else {
                        hir::RunClass::Scalar
                    }
                }
            }
        }
        hir::ExprKind::Dot(ref e, _) => expr_run_class(state, e),
        hir::ExprKind::SwizzleSelector(ref e, _) => expr_run_class(state, e),
        hir::ExprKind::PostInc(ref e) => expr_run_class(state, e),
        hir::ExprKind::PostDec(ref e) => expr_run_class(state, e),
        hir::ExprKind::Comma(_, ref e) => expr_run_class(state, e),
        hir::ExprKind::Cond(_, ref e) => expr_run_class(state, e),
        hir::ExprKind::CondMask => hir::RunClass::Vector,
    }
}

pub fn show_hir_expr(state: &OutputState, expr: &hir::Expr) {
    show_hir_expr_inner(state, expr, false);
}

pub fn show_hir_expr_inner(state: &OutputState, expr: &hir::Expr, top_level: bool) {
    match expr.kind {
        hir::ExprKind::Variable(ref i) => show_sym(state, i),
        hir::ExprKind::IntConst(ref x) => {
            let _ = write!(state, "{}", x);
        }
        hir::ExprKind::UIntConst(ref x) => {
            let _ = write!(state, "{}u", x);
        }
        hir::ExprKind::BoolConst(ref x) => {
            let _ = write!(state, "{}", x);
        }
        hir::ExprKind::FloatConst(ref x) => show_float(state, *x),
        hir::ExprKind::DoubleConst(ref x) => show_double(state, *x),
        hir::ExprKind::Unary(ref op, ref e) => {
            show_unary_op(state, &op);
            state.write("(");
            show_hir_expr(state, &e);
            state.write(")");
        }
        hir::ExprKind::Binary(ref op, ref l, ref r) => {
            state.write("(");
            show_hir_expr(state, &l);
            state.write(")");
            show_binary_op(state, &op);
            state.write("(");
            show_hir_expr(state, &r);
            state.write(")");
        }
        hir::ExprKind::Ternary(ref c, ref s, ref e) => {
            if state.output_cxx && expr_run_class(state, c) != hir::RunClass::Scalar {
                state.write("if_then_else(");
                show_hir_expr(state, &c);
                state.write(", ");
                show_hir_expr(state, &s);
                state.write(", ");
                show_hir_expr(state, &e);
                state.write(")");
            } else {
                show_hir_expr(state, &c);
                state.write(" ? ");
                show_hir_expr(state, &s);
                state.write(" : ");
                show_hir_expr(state, &e);
            }
        }
        hir::ExprKind::Assignment(ref v, ref op, ref e) => {
            let is_output = hir::is_output(v, &state.hir).is_some();
            let is_scalar_var = expr_run_class(state, v) == hir::RunClass::Scalar;
            let is_scalar_expr = expr_run_class(state, e) == hir::RunClass::Scalar;
            let force_scalar = is_scalar_var && !is_scalar_expr;

            if let Some(mask) = &state.mask {
                let is_scalar_mask = expr_run_class(state, mask) == hir::RunClass::Scalar;
                let force_scalar_mask = is_scalar_var && is_scalar_expr && !is_scalar_mask;

                if force_scalar || force_scalar_mask {
                    if top_level {
                        state.write("if (");
                    } else {
                        state.write("(");
                    }
                } else {
                    state.is_lval.set(true);
                    show_hir_expr(state, &v);
                    state.is_lval.set(false);
                    state.write(" = if_then_else(");
                }

                if is_output && state.return_declared {
                    state.write("((");
                    show_hir_expr(state, mask);
                    state.write(")&ret_mask)");
                } else {
                    show_hir_expr(state, mask);
                }
                if force_scalar || force_scalar_mask {
                    if top_level {
                        state.write("[0]) { ");
                    } else {
                        state.write("[0] ? ");
                    }
                    state.is_lval.set(true);
                    show_hir_expr(state, &v);
                    state.is_lval.set(false);
                    state.write(" = ");
                } else {
                    state.write(",");
                }

                if op != &syntax::AssignmentOp::Equal {
                    show_hir_expr(state, &v);
                }

                match *op {
                    syntax::AssignmentOp::Equal => {}
                    syntax::AssignmentOp::Mult => {
                        state.write("*");
                    }
                    syntax::AssignmentOp::Div => {
                        state.write("/");
                    }
                    syntax::AssignmentOp::Mod => {
                        state.write("%");
                    }
                    syntax::AssignmentOp::Add => {
                        state.write("+");
                    }
                    syntax::AssignmentOp::Sub => {
                        state.write("-");
                    }
                    syntax::AssignmentOp::LShift => {
                        state.write("<<");
                    }
                    syntax::AssignmentOp::RShift => {
                        state.write(">>");
                    }
                    syntax::AssignmentOp::And => {
                        state.write("&");
                    }
                    syntax::AssignmentOp::Xor => {
                        state.write("^");
                    }
                    syntax::AssignmentOp::Or => {
                        state.write("|");
                    }
                }
                if force_scalar {
                    state.write("force_scalar(");
                }
                show_hir_expr(state, &e);
                if force_scalar {
                    state.write(")");
                }
                if force_scalar || force_scalar_mask {
                    if top_level {
                        state.write("; }");
                    } else {
                        state.write(" : ");
                        show_hir_expr(state, &v);
                        state.write(")");
                    }
                } else {
                    state.write(",");
                    show_hir_expr(state, &v);
                    state.write(")");
                }
            } else {
                state.is_lval.set(true);
                show_hir_expr(state, &v);
                state.is_lval.set(false);
                state.write(" ");

                if is_output && state.return_declared {
                    state.write("= ");
                    if force_scalar {
                        state.write("force_scalar(");
                    }
                    state.write("if_then_else(ret_mask,");

                    if op != &syntax::AssignmentOp::Equal {
                        show_hir_expr(state, &v);
                    }

                    match *op {
                        syntax::AssignmentOp::Equal => {}
                        syntax::AssignmentOp::Mult => {
                            state.write("*");
                        }
                        syntax::AssignmentOp::Div => {
                            state.write("/");
                        }
                        syntax::AssignmentOp::Mod => {
                            state.write("%");
                        }
                        syntax::AssignmentOp::Add => {
                            state.write("+");
                        }
                        syntax::AssignmentOp::Sub => {
                            state.write("-");
                        }
                        syntax::AssignmentOp::LShift => {
                            state.write("<<");
                        }
                        syntax::AssignmentOp::RShift => {
                            state.write(">>");
                        }
                        syntax::AssignmentOp::And => {
                            state.write("&");
                        }
                        syntax::AssignmentOp::Xor => {
                            state.write("^");
                        }
                        syntax::AssignmentOp::Or => {
                            state.write("|");
                        }
                    }
                    show_hir_expr(state, &e);
                    state.write(",");
                    show_hir_expr(state, &v);
                    state.write(")");
                } else {
                    show_assignment_op(state, &op);
                    state.write(" ");
                    if force_scalar {
                        state.write("force_scalar(");
                    }
                    show_hir_expr(state, &e);
                }

                if force_scalar {
                    state.write(")");
                }
            }
        }
        hir::ExprKind::Bracket(ref e, ref indx) => {
            show_hir_expr(state, &e);
            state.write("[");
            for dimension in indx {
                show_hir_expr(state, dimension);
            }
            state.write("]");
        }
        hir::ExprKind::FunCall(ref fun, ref args) => {
            let mut cond_mask: u32 = 0;
            let mut adapt_mask: u32 = 0;
            let mut has_ret = false;
            let mut array_constructor = false;

            let mut arg_mask: u32 = 0;
            for (idx, e) in args.iter().enumerate() {
                if expr_run_class(state, e) == hir::RunClass::Vector {
                    arg_mask |= 1 << idx;
                }
            }

            match fun {
                hir::FunIdentifier::Constructor(t) => {
                    let is_scalar = state.is_scalar.replace(arg_mask == 0);
                    show_type(state, t);
                    state.is_scalar.set(is_scalar);
                    array_constructor = t.array_sizes.is_some();
                }
                hir::FunIdentifier::Identifier(name) => {
                    if state.output_cxx {
                        let sym = state.hir.sym(*name);
                        match &sym.decl {
                            hir::SymDecl::NativeFunction(..) => {
                                if sym.name == "texelFetchOffset" && args.len() >= 4 {
                                    if let Some((sampler, base, x, y)) = hir::get_texel_fetch_offset(
                                        &state.hir, &args[0], &args[1], &args[3],
                                    ) {
                                        let base_sym = state.hir.sym(base);
                                        let sampler_sym = state.hir.sym(sampler);
                                        add_used_global(state, &sampler);
                                        if let hir::SymDecl::Global(..) = &base_sym.decl {
                                            add_used_global(state, &base);
                                        }
                                        write!(
                                            state,
                                            "texelFetchUnchecked({}, {}_{}_fetch, {}, {})",
                                            sampler_sym.name,
                                            sampler_sym.name,
                                            base_sym.name,
                                            x,
                                            y,
                                        );
                                        return;
                                    }
                                } else if sym.name.starts_with("swgl_commitDithered") {
                                    state.used_fragcoord.set(
                                        state.used_fragcoord.get() | 1 | 2);
                                }
                                show_sym(state, name)
                            }
                            hir::SymDecl::UserFunction(ref fd, ref _run_class) => {
                                if (state.mask.is_some() || state.return_declared) &&
                                    !fd.globals.is_empty()
                                {
                                    cond_mask |= 1 << 31;
                                }
                                let mut param_mask: u32 = 0;
                                for (idx, (param, e)) in
                                    fd.prototype.parameters.iter().zip(args.iter()).enumerate()
                                {
                                    if let hir::FunctionParameterDeclaration::Named(qual, p) = param
                                    {
                                        if symbol_run_class(&state.hir.sym(p.sym).decl, arg_mask)
                                            == hir::RunClass::Vector
                                        {
                                            param_mask |= 1 << idx;
                                        }
                                        match qual {
                                            Some(hir::ParameterQualifier::InOut)
                                            | Some(hir::ParameterQualifier::Out) => {
                                                if state.mask.is_some() || state.return_declared {
                                                    cond_mask |= 1 << idx;
                                                }
                                                if (!arg_mask & param_mask & (1 << idx)) != 0 {
                                                    if adapt_mask == 0 {
                                                        state.write(if top_level {
                                                            "{ "
                                                        } else {
                                                            "({ "
                                                        });
                                                    }
                                                    show_type(state, &p.ty);
                                                    write!(state, " _arg{}_ = ", idx);
                                                    show_hir_expr(state, e);
                                                    state.write("; ");
                                                    adapt_mask |= 1 << idx;
                                                }
                                            }
                                            _ => {}
                                        }
                                    }
                                }
                                if adapt_mask != 0 &&
                                    fd.prototype.ty.kind != hir::TypeKind::Void &&
                                    !top_level
                                {
                                    state.write("auto _ret_ = ");
                                    has_ret = true;
                                }
                                show_sym(state, name);
                                let mut deps = state.deps.borrow_mut();
                                let dep_key = (
                                    *name,
                                    if cond_mask != 0 {
                                        param_mask | (1 << 31)
                                    } else {
                                        param_mask
                                    },
                                );
                                if !deps.contains(&dep_key) {
                                    deps.push(dep_key);
                                }
                            }
                            hir::SymDecl::Struct(..) => {
                                show_sym(state, name);
                                if arg_mask == 0 {
                                    state.write("_scalar");
                                }
                            }
                            _ => panic!("bad identifier to function call"),
                        }
                    }
                }
            }

            if array_constructor {
                state.write("{{");
            } else {
                state.write("(");
            }

            for (idx, e) in args.iter().enumerate() {
                if idx != 0 {
                    state.write(", ");
                }
                if (adapt_mask & (1 << idx)) != 0 {
                    write!(state, "_arg{}_", idx);
                } else {
                    show_hir_expr(state, e);
                }
            }

            if cond_mask != 0 {
                if !args.is_empty() {
                    state.write(", ");
                }
                if let Some(mask) = &state.mask {
                    if state.return_declared {
                        state.write("(");
                        show_hir_expr(state, mask);
                        state.write(")&ret_mask");
                    } else {
                        show_hir_expr(state, mask);
                    }
                } else if state.return_declared {
                    state.write("ret_mask");
                } else {
                    state.write("~0");
                }
            }

            if array_constructor {
                state.write("}}");
            } else {
                state.write(")");
            }

            if adapt_mask != 0 {
                state.write("; ");
                for (idx, e) in args.iter().enumerate() {
                    if (adapt_mask & (1 << idx)) != 0 {
                        state.is_lval.set(true);
                        show_hir_expr(state, e);
                        state.is_lval.set(false);
                        write!(state, " = force_scalar(_arg{}_); ", idx);
                    }
                }
                if has_ret {
                    state.write("_ret_; })");
                } else {
                    state.write(if top_level { "}" } else { "})" });
                }
            }
        }
        hir::ExprKind::Dot(ref e, ref i) => {
            state.write("(");
            show_hir_expr(state, &e);
            state.write(")");
            state.write(".");
            show_identifier(state, i);
        }
        hir::ExprKind::SwizzleSelector(ref e, ref s) => {
            if state.output_cxx {
                if let hir::ExprKind::Variable(ref sym) = &e.kind {
                    if state.hir.sym(*sym).name == "gl_FragCoord" {
                        state.used_fragcoord.set(
                            s.components.iter().fold(
                                state.used_fragcoord.get(),
                                |used, c| used | (1 << c)));
                    }
                }
                state.write("(");
                show_hir_expr(state, &e);
                state.write(").");
                if s.components.len() == 1 {
                    // For single component swizzles, output a field access to
                    // avoid stressing inlining of sel().
                    state.write(&s.to_field_set(hir::FieldSet::Xyzw));
                } else {
                    if state.is_lval.get() && s.components.len() > 1 {
                        state.write("lsel(");
                    } else {
                        state.write("sel(");
                    }
                    for (i, c) in s.to_string().chars().enumerate() {
                        if i > 0 {
                            state.write(",");
                        }
                        write!(state, "{}", c.to_uppercase());
                    }
                    state.write(")");
                }
            } else {
                state.write("(");
                show_hir_expr(state, &e);
                state.write(")");
                state.write(".");
                state.write(&s.to_string());
            }
        }
        hir::ExprKind::PostInc(ref e) => {
            show_hir_expr(state, &e);
            state.write("++");
        }
        hir::ExprKind::PostDec(ref e) => {
            show_hir_expr(state, &e);
            state.write("--");
        }
        hir::ExprKind::Comma(ref a, ref b) => {
            show_hir_expr(state, &a);
            state.write(", ");
            show_hir_expr(state, &b);
        }
        hir::ExprKind::Cond(index, _) => {
            write!(state, "_c{}_", index);
        }
        hir::ExprKind::CondMask => {
            state.write("_cond_mask_");
        }
    }
}

pub fn show_expr(state: &OutputState, expr: &syntax::Expr) {
    match *expr {
        syntax::Expr::Variable(ref i) => show_identifier(state, &i),
        syntax::Expr::IntConst(ref x) => {
            let _ = write!(state, "{}", x);
        }
        syntax::Expr::UIntConst(ref x) => {
            let _ = write!(state, "{}u", x);
        }
        syntax::Expr::BoolConst(ref x) => {
            let _ = write!(state, "{}", x);
        }
        syntax::Expr::FloatConst(ref x) => show_float(state, *x),
        syntax::Expr::DoubleConst(ref x) => show_double(state, *x),
        syntax::Expr::Unary(ref op, ref e) => {
            show_unary_op(state, &op);
            state.write("(");
            show_expr(state, &e);
            state.write(")");
        }
        syntax::Expr::Binary(ref op, ref l, ref r) => {
            state.write("(");
            show_expr(state, &l);
            state.write(")");
            show_binary_op(state, &op);
            state.write("(");
            show_expr(state, &r);
            state.write(")");
        }
        syntax::Expr::Ternary(ref c, ref s, ref e) => {
            show_expr(state, &c);
            state.write(" ? ");
            show_expr(state, &s);
            state.write(" : ");
            show_expr(state, &e);
        }
        syntax::Expr::Assignment(ref v, ref op, ref e) => {
            show_expr(state, &v);
            state.write(" ");
            show_assignment_op(state, &op);
            state.write(" ");
            show_expr(state, &e);
        }
        syntax::Expr::Bracket(ref e, ref a) => {
            show_expr(state, &e);
            show_array_spec(state, &a);
        }
        syntax::Expr::FunCall(ref fun, ref args) => {
            show_function_identifier(state, &fun);
            state.write("(");

            if !args.is_empty() {
                let mut args_iter = args.iter();
                let first = args_iter.next().unwrap();
                show_expr(state, first);

                for e in args_iter {
                    state.write(", ");
                    show_expr(state, e);
                }
            }

            state.write(")");
        }
        syntax::Expr::Dot(ref e, ref i) => {
            state.write("(");
            show_expr(state, &e);
            state.write(")");
            state.write(".");
            show_identifier(state, &i);
        }
        syntax::Expr::PostInc(ref e) => {
            show_expr(state, &e);
            state.write("++");
        }
        syntax::Expr::PostDec(ref e) => {
            show_expr(state, &e);
            state.write("--");
        }
        syntax::Expr::Comma(ref a, ref b) => {
            show_expr(state, &a);
            state.write(", ");
            show_expr(state, &b);
        }
    }
}

pub fn show_unary_op(state: &OutputState, op: &syntax::UnaryOp) {
    match *op {
        syntax::UnaryOp::Inc => {
            state.write("++");
        }
        syntax::UnaryOp::Dec => {
            state.write("--");
        }
        syntax::UnaryOp::Add => {
            state.write("+");
        }
        syntax::UnaryOp::Minus => {
            state.write("-");
        }
        syntax::UnaryOp::Not => {
            state.write("!");
        }
        syntax::UnaryOp::Complement => {
            state.write("~");
        }
    }
}

pub fn show_binary_op(state: &OutputState, op: &syntax::BinaryOp) {
    match *op {
        syntax::BinaryOp::Or => {
            state.write("||");
        }
        syntax::BinaryOp::Xor => {
            state.write("^^");
        }
        syntax::BinaryOp::And => {
            state.write("&&");
        }
        syntax::BinaryOp::BitOr => {
            state.write("|");
        }
        syntax::BinaryOp::BitXor => {
            state.write("^");
        }
        syntax::BinaryOp::BitAnd => {
            state.write("&");
        }
        syntax::BinaryOp::Equal => {
            state.write("==");
        }
        syntax::BinaryOp::NonEqual => {
            state.write("!=");
        }
        syntax::BinaryOp::LT => {
            state.write("<");
        }
        syntax::BinaryOp::GT => {
            state.write(">");
        }
        syntax::BinaryOp::LTE => {
            state.write("<=");
        }
        syntax::BinaryOp::GTE => {
            state.write(">=");
        }
        syntax::BinaryOp::LShift => {
            state.write("<<");
        }
        syntax::BinaryOp::RShift => {
            state.write(">>");
        }
        syntax::BinaryOp::Add => {
            state.write("+");
        }
        syntax::BinaryOp::Sub => {
            state.write("-");
        }
        syntax::BinaryOp::Mult => {
            state.write("*");
        }
        syntax::BinaryOp::Div => {
            state.write("/");
        }
        syntax::BinaryOp::Mod => {
            state.write("%");
        }
    }
}

pub fn show_assignment_op(state: &OutputState, op: &syntax::AssignmentOp) {
    match *op {
        syntax::AssignmentOp::Equal => {
            state.write("=");
        }
        syntax::AssignmentOp::Mult => {
            state.write("*=");
        }
        syntax::AssignmentOp::Div => {
            state.write("/=");
        }
        syntax::AssignmentOp::Mod => {
            state.write("%=");
        }
        syntax::AssignmentOp::Add => {
            state.write("+=");
        }
        syntax::AssignmentOp::Sub => {
            state.write("-=");
        }
        syntax::AssignmentOp::LShift => {
            state.write("<<=");
        }
        syntax::AssignmentOp::RShift => {
            state.write(">>=");
        }
        syntax::AssignmentOp::And => {
            state.write("&=");
        }
        syntax::AssignmentOp::Xor => {
            state.write("^=");
        }
        syntax::AssignmentOp::Or => {
            state.write("|=");
        }
    }
}

pub fn show_function_identifier(state: &OutputState, i: &syntax::FunIdentifier) {
    match *i {
        syntax::FunIdentifier::Identifier(ref n) => show_identifier(state, &n),
        syntax::FunIdentifier::Expr(ref e) => show_expr(state, &*e),
    }
}

pub fn show_hir_function_identifier(state: &OutputState, i: &hir::FunIdentifier) {
    match *i {
        hir::FunIdentifier::Identifier(ref n) => show_sym(state, n),
        hir::FunIdentifier::Constructor(ref t) => show_type(state, &*t),
    }
}

pub fn show_declaration(state: &mut OutputState, d: &hir::Declaration) {
    show_indent(state);
    match *d {
        hir::Declaration::FunctionPrototype(ref proto) => {
            if !state.output_cxx {
                show_function_prototype(state, &proto);
                state.write(";\n");
            }
        }
        hir::Declaration::InitDeclaratorList(ref list) => {
            show_init_declarator_list(state, &list);
            state.write(";\n");

            if state.output_cxx {
                let base = list.head.name;
                let base_sym = state.hir.sym(base);
                if let hir::SymDecl::Local(..) = &base_sym.decl {
                    let mut texel_fetches = state.texel_fetches.borrow_mut();
                    while let Some(idx) = texel_fetches.iter().position(|&(_, b, _)| b == base)
                    {
                        let (sampler, _, offsets) = texel_fetches.remove(idx);
                        let sampler_sym = state.hir.sym(sampler);
                        define_texel_fetch_ptr(state, &base_sym, &sampler_sym, &offsets);
                    }
                }
            }
        }
        hir::Declaration::Precision(ref qual, ref ty) => {
            if !state.output_cxx {
                show_precision_qualifier(state, &qual);
                show_type_specifier(state, &ty);
                state.write(";\n");
            }
        }
        hir::Declaration::Block(ref _block) => {
            panic!();
            //show_block(state, &block);
            //state.write(";\n");
        }
        hir::Declaration::Global(ref qual, ref identifiers) => {
            // We only want to output GLSL layout qualifiers if not C++
            if !state.output_cxx {
                show_type_qualifier(state, &qual);

                if !identifiers.is_empty() {
                    let mut iter = identifiers.iter();
                    let first = iter.next().unwrap();
                    show_identifier(state, first);

                    for identifier in iter {
                        let _ = write!(state, ", {}", identifier);
                    }
                }

                state.write(";\n");
            }
        }
        hir::Declaration::StructDefinition(ref sym) => {
            show_sym_decl(state, sym);

            state.write(";\n");
        }
    }
}

pub fn show_function_prototype(state: &mut OutputState, fp: &hir::FunctionPrototype) {
    let is_scalar = state.is_scalar.replace(!state.return_vector);
    show_type(state, &fp.ty);
    state.is_scalar.set(is_scalar);

    state.write(" ");
    show_identifier(state, &fp.name);

    state.write("(");

    if !fp.parameters.is_empty() {
        let mut iter = fp.parameters.iter();
        let first = iter.next().unwrap();
        show_function_parameter_declaration(state, first);

        for param in iter {
            state.write(", ");
            show_function_parameter_declaration(state, param);
        }
    }

    if state.output_cxx && (state.vector_mask & (1 << 31)) != 0 {
        if !fp.parameters.is_empty() {
            state.write(", ");
        }
        state.write("I32 _cond_mask_");
    }

    state.write(")");
}

pub fn show_function_parameter_declaration(
    state: &mut OutputState,
    p: &hir::FunctionParameterDeclaration,
) {
    match *p {
        hir::FunctionParameterDeclaration::Named(ref qual, ref fpd) => {
            if state.output_cxx {
                let is_scalar = state.is_scalar.replace(
                    symbol_run_class(&state.hir.sym(fpd.sym).decl, state.vector_mask)
                        == hir::RunClass::Scalar,
                );
                show_type(state, &fpd.ty);
                state.is_scalar.set(is_scalar);
                show_parameter_qualifier(state, qual);
            } else {
                show_parameter_qualifier(state, qual);
                state.write(" ");
                show_type(state, &fpd.ty);
            }
            state.write(" ");
            show_identifier_and_type(state, &fpd.name, &fpd.ty);
        }
        hir::FunctionParameterDeclaration::Unnamed(ref qual, ref ty) => {
            if state.output_cxx {
                show_type_specifier(state, ty);
                show_parameter_qualifier(state, qual);
            } else {
                show_parameter_qualifier(state, qual);
                state.write(" ");
                show_type_specifier(state, ty);
            }
        }
    }
}

pub fn show_init_declarator_list(state: &mut OutputState, i: &hir::InitDeclaratorList) {
    show_single_declaration(state, &i.head);

    for decl in &i.tail {
        state.write(", ");
        show_single_declaration_no_type(state, decl);
    }
}

pub fn show_single_declaration(state: &mut OutputState, d: &hir::SingleDeclaration) {
    if state.output_cxx {
        show_single_declaration_cxx(state, d)
    } else {
        show_single_declaration_glsl(state, d)
    }
}

pub fn show_single_declaration_glsl(state: &mut OutputState, d: &hir::SingleDeclaration) {
    if let Some(ref qual) = d.qualifier {
        show_type_qualifier(state, &qual);
        state.write(" ");
    }

    let sym = state.hir.sym(d.name);
    match &sym.decl {
        hir::SymDecl::Global(storage, interpolation, ..) => {
            show_storage_class(state, storage);
            if let Some(i) = interpolation {
                show_interpolation_qualifier(state, i);
            }
        }
        hir::SymDecl::Local(storage, ..) => show_storage_class(state, storage),
        _ => panic!("should be variable"),
    }

    if let Some(ty_def) = d.ty_def {
        show_sym_decl(state, &ty_def);
    } else {
        show_type(state, &d.ty);
    }

    state.write(" ");
    state.write(sym.name.as_str());

    if let Some(ref arr_spec) = d.ty.array_sizes {
        show_array_sizes(state, &arr_spec);
    }

    if let Some(ref initializer) = d.initializer {
        state.write(" = ");
        show_initializer(state, initializer);
    }
}

fn symbol_run_class(decl: &hir::SymDecl, vector_mask: u32) -> hir::RunClass {
    let run_class = match decl {
        hir::SymDecl::Global(_, _, _, run_class) => *run_class,
        hir::SymDecl::Local(_, _, run_class) => *run_class,
        _ => hir::RunClass::Vector,
    };
    match run_class {
        hir::RunClass::Scalar => hir::RunClass::Scalar,
        hir::RunClass::Dependent(mask) => {
            if (mask & vector_mask) != 0 {
                hir::RunClass::Vector
            } else {
                hir::RunClass::Scalar
            }
        }
        _ => hir::RunClass::Vector,
    }
}

pub fn show_single_declaration_cxx(state: &mut OutputState, d: &hir::SingleDeclaration) {
    let sym = state.hir.sym(d.name);
    if state.kind == ShaderKind::Vertex {
        match &sym.decl {
            hir::SymDecl::Global(hir::StorageClass::Uniform, ..) |
            hir::SymDecl::Global(hir::StorageClass::Sampler(_), ..) |
            hir::SymDecl::Global(hir::StorageClass::Out, _, _, hir::RunClass::Scalar) => {
                state.write("// ");
            }
            _ => {}
        }
    } else {
        match &sym.decl {
            hir::SymDecl::Global(hir::StorageClass::FragColor(index), ..) => {
                let fragcolor = match index {
                    0 => "gl_FragColor",
                    1 => "gl_SecondaryFragColor",
                    _ => panic!(),
                };
                write!(state, "#define {} {}\n", sym.name, fragcolor);
                show_indent(state);
                state.write("// ");
            }
            hir::SymDecl::Global(hir::StorageClass::Out, ..) => {
                write!(state, "#define {} gl_FragColor\n", sym.name);
                show_indent(state);
                state.write("// ");
            }
            hir::SymDecl::Global(hir::StorageClass::Uniform, ..) |
            hir::SymDecl::Global(hir::StorageClass::Sampler(_), ..) |
            hir::SymDecl::Global(hir::StorageClass::In, _, _, hir::RunClass::Scalar) => {
                state.write("// ");
            }
            _ => {}
        }
    }
    let is_scalar = state
        .is_scalar
        .replace(symbol_run_class(&sym.decl, state.vector_mask) == hir::RunClass::Scalar);

    if let Some(ref _array) = d.ty.array_sizes {
        show_type(state, &d.ty);
    } else {
        if let Some(ty_def) = d.ty_def {
            show_sym_decl(state, &ty_def);
        } else {
            show_type(state, &d.ty);
        }
    }

    // XXX: this is pretty grotty
    state.write(" ");
    show_sym_decl(state, &d.name);

    state.is_scalar.set(is_scalar);

    if let Some(ref initializer) = d.initializer {
        state.write(" = ");
        show_initializer(state, initializer);
    }
}

pub fn show_single_declaration_no_type(state: &OutputState, d: &hir::SingleDeclarationNoType) {
    show_arrayed_identifier(state, &d.ident);

    if let Some(ref initializer) = d.initializer {
        state.write(" = ");
        show_initializer(state, initializer);
    }
}

pub fn show_initializer(state: &OutputState, i: &hir::Initializer) {
    match *i {
        hir::Initializer::Simple(ref e) => show_hir_expr(state, e),
        hir::Initializer::List(ref list) => {
            let mut iter = list.0.iter();
            let first = iter.next().unwrap();

            state.write("{ ");
            show_initializer(state, first);

            for ini in iter {
                state.write(", ");
                show_initializer(state, ini);
            }

            state.write(" }");
        }
    }
}

/*
pub fn show_block(state: &mut OutputState, b: &hir::Block) {
  show_type_qualifier(state, &b.qualifier);
  state.write(" ");
  show_identifier(state, &b.name);
  state.write(" {");

  for field in &b.fields {
    show_struct_field(state, field);
    state.write("\n");
  }
  state.write("}");

  if let Some(ref ident) = b.identifier {
    show_arrayed_identifier(state, ident);
  }
}
*/

// This is a hack to run through the first time with an empty writter to find if 'return' is declared.
pub fn has_conditional_return(state: &mut OutputState, cst: &hir::CompoundStatement) -> bool {
    let buffer = state.push_buffer();
    show_compound_statement(state, cst);
    state.pop_buffer(buffer);
    let result = state.return_declared;
    state.return_declared = false;
    result
}

fn define_texel_fetch_ptr(
    state: &OutputState,
    base_sym: &hir::Symbol,
    sampler_sym: &hir::Symbol,
    offsets: &hir::TexelFetchOffsets,
) {
    show_indent(state);
    write!(
        state,
        "auto {}_{}_fetch = texelFetchPtr({}, {}, {}, {}, {}, {});\n",
        sampler_sym.name,
        base_sym.name,
        sampler_sym.name,
        base_sym.name,
        offsets.min_x,
        offsets.max_x,
        offsets.min_y,
        offsets.max_y,
    );
}

pub fn show_function_definition(
    state: &mut OutputState,
    fd: &hir::FunctionDefinition,
    vector_mask: u32,
) {
    //  println!("start {:?} {:?}", fd.prototype.name, vector_mask);
    if state.output_cxx && fd.prototype.name.as_str() == "main" {
        state.write("ALWAYS_INLINE ");
    }
    show_function_prototype(state, &fd.prototype);
    state.write(" ");
    state.return_type = Some(Box::new(fd.prototype.ty.clone()));

    if state.output_cxx && (vector_mask & (1 << 31)) != 0 {
        state.mask = Some(Box::new(hir::Expr {
            kind: hir::ExprKind::CondMask,
            ty: hir::Type::new(hir::TypeKind::Bool),
        }));
    }

    show_indent(state);
    state.write("{\n");

    state.indent();
    if has_conditional_return(state, &fd.body) {
        show_indent(state);
        state.write(if state.return_vector {
            "I32"
        } else {
            "int32_t"
        });
        state.write(" ret_mask = ");
        if let Some(mask) = &state.mask {
            show_hir_expr(state, mask);
        } else {
            state.write("~0");
        }
        state.write(";\n");
        // XXX: the cloning here is bad
        show_indent(state);
        if fd.prototype.ty != Type::new(hir::TypeKind::Void) {
            let is_scalar = state.is_scalar.replace(!state.return_vector);
            show_type(state, &state.return_type.clone().unwrap());
            state.write(" ret;\n");
            state.is_scalar.set(is_scalar);
        }
    }

    if state.output_cxx {
        match fd.prototype.name.as_str() {
            "swgl_drawSpanRGBA8" |
            "swgl_drawSpanR8" => {
                // Partial spans are not drawn using span shaders, but rather drawn with a fragment shader
                // where the span shader left off. We need to undo any changes to the interpolants made by
                // the span shaders so that we can reset the interpolants to where the fragment shader
                // expects them. We do this by saving them in an _Undo_ struct on entry to the span shader,
                // and then restore them in the _Undo_ struct destructor.
                let mut needs_undo = vec![];
                for global in &fd.globals {
                    let sym = state.hir.sym(*global);
                    match &sym.decl {
                        hir::SymDecl::Global(hir::StorageClass::In, _, ty, hir::RunClass::Vector) => {
                            if needs_undo.is_empty() {
                                state.write("struct _Undo_ {\nSelf* self;\n");
                            }
                            show_type(state, ty);
                            write!(state, " {};\n", sym.name);
                            needs_undo.push(sym.name.clone());
                        }
                        _ => {}
                    }
                }
                if !needs_undo.is_empty() {
                    state.write("explicit _Undo_(Self* self) : self(self)");
                    for name in &needs_undo {
                        write!(state, ", {0}(self->{0})", name);
                    }
                    state.write(" {}\n");
                    state.write("~_Undo_() {\n");
                    for name in &needs_undo {
                        write!(state, "self->{0} = {0};\n", name);
                    }
                    state.write("}} _undo_(this);\n");
                }
            }
            _ => {}
        }

        let mut texel_fetches = state.texel_fetches.borrow_mut();
        texel_fetches.clear();
        for ((sampler, base), offsets) in fd.texel_fetches.iter() {
            add_used_global(state, sampler);
            let sampler_sym = state.hir.sym(*sampler);
            let base_sym = state.hir.sym(*base);
            match &base_sym.decl {
                hir::SymDecl::Global(..) => {
                    add_used_global(state, base);
                    define_texel_fetch_ptr(state, &base_sym, &sampler_sym, &offsets);
                }
                hir::SymDecl::Local(..) => {
                    if fd.prototype.has_parameter(*base) {
                        define_texel_fetch_ptr(state, &base_sym, &sampler_sym, &offsets);
                    } else {
                        texel_fetches.push((*sampler, *base, offsets.clone()));
                    }
                }
                _ => panic!(),
            }
        }
    }

    for st in &fd.body.statement_list {
        show_statement(state, st);
    }

    if state.return_declared {
        show_indent(state);
        if fd.prototype.ty == Type::new(hir::TypeKind::Void) {
            state.write("return;\n");
        } else {
            state.write("return ret;\n");
        }
    }
    state.outdent();

    show_indent(state);
    state.write("}\n");
    // println!("end {:?}", fd.prototype.name);

    state.return_type = None;
    state.return_declared = false;
    state.mask = None;
}

pub fn show_compound_statement(state: &mut OutputState, cst: &hir::CompoundStatement) {
    show_indent(state);
    state.write("{\n");

    state.indent();
    for st in &cst.statement_list {
        show_statement(state, st);
    }
    state.outdent();

    show_indent(state);
    state.write("}\n");
}

pub fn show_statement(state: &mut OutputState, st: &hir::Statement) {
    match *st {
        hir::Statement::Compound(ref cst) => show_compound_statement(state, cst),
        hir::Statement::Simple(ref sst) => show_simple_statement(state, sst),
    }
}

pub fn show_simple_statement(state: &mut OutputState, sst: &hir::SimpleStatement) {
    match *sst {
        hir::SimpleStatement::Declaration(ref d) => show_declaration(state, d),
        hir::SimpleStatement::Expression(ref e) => show_expression_statement(state, e),
        hir::SimpleStatement::Selection(ref s) => show_selection_statement(state, s),
        hir::SimpleStatement::Switch(ref s) => show_switch_statement(state, s),
        hir::SimpleStatement::Iteration(ref i) => show_iteration_statement(state, i),
        hir::SimpleStatement::Jump(ref j) => show_jump_statement(state, j),
    }
}

pub fn show_indent(state: &OutputState) {
    for _ in 0 .. state.indent {
        state.write(" ");
    }
}

pub fn show_expression_statement(state: &mut OutputState, est: &hir::ExprStatement) {
    show_indent(state);

    if let Some(ref e) = *est {
        show_hir_expr_inner(state, e, true);
    }

    state.write(";\n");
}

pub fn show_selection_statement(state: &mut OutputState, sst: &hir::SelectionStatement) {
    show_indent(state);

    if state.output_cxx &&
        (state.return_declared || expr_run_class(state, &sst.cond) != hir::RunClass::Scalar)
    {
        let (cond_index, mask) = if state.mask.is_none() || sst.else_stmt.is_some() {
            let cond = sst.cond.clone();
            state.cond_index += 1;
            let cond_index = state.cond_index;
            write!(state, "auto _c{}_ = ", cond_index);
            show_hir_expr(state, &cond);
            state.write(";\n");
            (
                cond_index,
                Box::new(hir::Expr {
                    kind: hir::ExprKind::Cond(cond_index, cond),
                    ty: hir::Type::new(hir::TypeKind::Bool),
                }),
            )
        } else {
            (0, sst.cond.clone())
        };

        let previous = mem::replace(&mut state.mask, None);
        state.mask = Some(match previous.clone() {
            Some(e) => {
                let cond = Box::new(hir::Expr {
                    kind: hir::ExprKind::Binary(syntax::BinaryOp::BitAnd, e, mask.clone()),
                    ty: hir::Type::new(hir::TypeKind::Bool),
                });
                state.cond_index += 1;
                let nested_cond_index = state.cond_index;
                show_indent(state);
                write!(state, "auto _c{}_ = ", nested_cond_index);
                show_hir_expr(state, &cond);
                state.write(";\n");
                Box::new(hir::Expr {
                    kind: hir::ExprKind::Cond(nested_cond_index, cond),
                    ty: hir::Type::new(hir::TypeKind::Bool),
                })
            }
            None => mask.clone(),
        });

        show_statement(state, &sst.body);
        state.mask = previous;

        if let Some(rest) = &sst.else_stmt {
            // invert the condition
            let inverted_cond = Box::new(hir::Expr {
                kind: hir::ExprKind::Unary(UnaryOp::Complement, mask),
                ty: hir::Type::new(hir::TypeKind::Bool),
            });
            let previous = mem::replace(&mut state.mask, None);
            state.mask = Some(match previous.clone() {
                Some(e) => {
                    let cond = Box::new(hir::Expr {
                        kind: hir::ExprKind::Binary(syntax::BinaryOp::BitAnd, e, inverted_cond),
                        ty: hir::Type::new(hir::TypeKind::Bool),
                    });
                    show_indent(state);
                    write!(state, "_c{}_ = ", cond_index);
                    show_hir_expr(state, &cond);
                    state.write(";\n");
                    Box::new(hir::Expr {
                        kind: hir::ExprKind::Cond(cond_index, cond),
                        ty: hir::Type::new(hir::TypeKind::Bool),
                    })
                }
                None => inverted_cond,
            });

            show_statement(state, rest);
            state.mask = previous;
        }
    } else {
        state.write("if (");
        show_hir_expr(state, &sst.cond);
        state.write(") {\n");

        state.indent();
        show_statement(state, &sst.body);
        state.outdent();

        show_indent(state);
        if let Some(rest) = &sst.else_stmt {
            state.write("} else ");
            show_statement(state, rest);
        } else {
            state.write("}\n");
        }
    }
}

fn case_stmts_to_if_stmts(stmts: &[Statement], last: bool) -> (Option<Box<Statement>>, bool) {
    // Look for jump statements and remove them
    // We currently are pretty strict on the form that the statement
    // list needs to be in. This can be loosened as needed.
    let mut fallthrough = false;
    let cstmt = match &stmts[..] {
        [hir::Statement::Compound(c)] => match c.statement_list.split_last() {
            Some((hir::Statement::Simple(s), rest)) => match **s {
                hir::SimpleStatement::Jump(hir::JumpStatement::Break) => hir::CompoundStatement {
                    statement_list: rest.to_owned(),
                },
                _ => panic!("fall through not supported"),
            },
            _ => panic!("empty compound"),
        },
        [hir::Statement::Simple(s)] => {
            match **s {
                hir::SimpleStatement::Jump(hir::JumpStatement::Break) => hir::CompoundStatement {
                    statement_list: Vec::new(),
                },
                _ => {
                    if last {
                        // we don't need a break at the end
                        hir::CompoundStatement {
                            statement_list: vec![hir::Statement::Simple(s.clone())],
                        }
                    } else {
                        panic!("fall through not supported {:?}", s)
                    }
                }
            }
        }
        [] => return (None, true),
        stmts => match stmts.split_last() {
            Some((hir::Statement::Simple(s), rest)) => match **s {
                hir::SimpleStatement::Jump(hir::JumpStatement::Break) => hir::CompoundStatement {
                    statement_list: rest.to_owned(),
                },
                _ => {
                    if !last {
                        fallthrough = true;
                    }
                    hir::CompoundStatement {
                        statement_list: stmts.to_owned(),
                    }
                }
            },
            _ => panic!("unexpected empty"),
        },
    };
    let stmts = Box::new(hir::Statement::Compound(Box::new(cstmt)));
    (Some(stmts), fallthrough)
}

fn build_selection<'a, I: Iterator<Item = &'a hir::Case>>(
    head: &Box<hir::Expr>,
    case: &hir::Case,
    mut cases: I,
    default: Option<&hir::Case>,
    previous_condition: Option<Box<hir::Expr>>,
    previous_stmts: Option<Box<hir::Statement>>,
) -> hir::SelectionStatement {
    let cond = match &case.label {
        hir::CaseLabel::Case(e) => Some(Box::new(hir::Expr {
            kind: hir::ExprKind::Binary(syntax::BinaryOp::Equal, head.clone(), e.clone()),
            ty: hir::Type::new(hir::TypeKind::Bool),
        })),
        hir::CaseLabel::Def => None,
    };

    // if we have two conditions join them
    let cond = match (&previous_condition, &cond) {
        (Some(prev), Some(cond)) => Some(Box::new(hir::Expr {
            kind: hir::ExprKind::Binary(syntax::BinaryOp::Or, prev.clone(), cond.clone()),
            ty: hir::Type::new(hir::TypeKind::Bool),
        })),
        (_, cond) => cond.clone(),
    };

    /*

    // find the next case that's not a default
    let next_case = loop {
      match cases.next() {
        Some(hir::Case { label: hir::CaseLabel::Def, ..}) => { },
        case => break case,
      }
    };*/

    let (cond, body, else_stmt) = match (cond, cases.next()) {
        (None, Some(next_case)) => {
            assert!(previous_stmts.is_none());
            // default so just move on to the next
            return build_selection(head, next_case, cases, default, None, None);
        }
        (Some(cond), Some(next_case)) => {
            assert!(previous_stmts.is_none());
            let (stmts, fallthrough) = case_stmts_to_if_stmts(&case.stmts, false);
            if !fallthrough && stmts.is_some() {
                (
                    cond,
                    stmts.unwrap(),
                    Some(Box::new(hir::Statement::Simple(Box::new(
                        hir::SimpleStatement::Selection(build_selection(
                            head, next_case, cases, default, None, None,
                        )),
                    )))),
                )
            } else {
                // empty so fall through to the next
                return build_selection(head, next_case, cases, default, Some(cond), stmts);
            }
        }
        (Some(cond), None) => {
            // non-default last
            assert!(previous_stmts.is_none());
            let (stmts, _) = case_stmts_to_if_stmts(&case.stmts, default.is_none());
            let stmts = stmts.expect("empty case labels unsupported at the end");
            // add the default case at the end if we have one
            (
                cond,
                stmts,
                match default {
                    Some(default) => {
                        let (default_stmts, fallthrough) =
                            case_stmts_to_if_stmts(&default.stmts, true);
                        assert!(!fallthrough);
                        Some(default_stmts.expect("empty default unsupported"))
                    }
                    None => None,
                },
            )
        }
        (None, None) => {
            // default, last

            assert!(default.is_some());

            let (stmts, fallthrough) = case_stmts_to_if_stmts(&case.stmts, true);
            let stmts = stmts.expect("empty default unsupported");
            assert!(!fallthrough);

            match previous_stmts {
                Some(previous_stmts) => {
                    let cond = previous_condition.expect("must have previous condition");
                    (cond, previous_stmts, Some(stmts))
                }
                None => {
                    let cond = Box::new(hir::Expr {
                        kind: hir::ExprKind::BoolConst(true),
                        ty: hir::Type::new(hir::TypeKind::Bool),
                    });
                    (cond, stmts, None)
                }
            }
        }
    };

    hir::SelectionStatement {
        cond,
        body,
        else_stmt,
    }
}

pub fn lower_switch_to_ifs(sst: &hir::SwitchStatement) -> hir::SelectionStatement {
    let default = sst.cases.iter().find(|x| x.label == hir::CaseLabel::Def);
    let mut cases = sst.cases.iter();
    let r = build_selection(&sst.head, cases.next().unwrap(), cases, default, None, None);
    r
}

fn is_declaration(stmt: &hir::Statement) -> bool {
    if let hir::Statement::Simple(s) = stmt {
        if let hir::SimpleStatement::Declaration(..) = **s {
            return true;
        }
    }
    return false;
}

pub fn show_switch_statement(state: &mut OutputState, sst: &hir::SwitchStatement) {
    if state.output_cxx && expr_run_class(state, &sst.head) != hir::RunClass::Scalar {
        // XXX: when lowering switches we end up with a mask that has
        // a bunch of mutually exclusive conditions.
        // It would be nice if we could fold them together.
        let ifs = lower_switch_to_ifs(sst);
        return show_selection_statement(state, &ifs);
    }

    show_indent(state);
    state.write("switch (");
    show_hir_expr(state, &sst.head);
    state.write(") {\n");
    state.indent();

    for case in &sst.cases {
        show_case_label(state, &case.label);
        state.indent();

        let has_declaration = case.stmts.iter().any(|x| is_declaration(x));
        // glsl allows declarations in switch statements while C requires them to be
        // in a compound statement. If we have a declaration wrap the statements in an block.
        // This will break some glsl shaders but keeps the saner ones working
        if has_declaration {
            show_indent(state);
            state.write("{\n");
            state.indent();
        }
        for st in &case.stmts {
            show_statement(state, st);
        }

        if has_declaration {
            show_indent(state);
            state.write("}\n");
            state.outdent();
        }

        state.outdent();
    }
    state.outdent();
    show_indent(state);
    state.write("}\n");
}

pub fn show_case_label(state: &mut OutputState, cl: &hir::CaseLabel) {
    show_indent(state);
    match *cl {
        hir::CaseLabel::Case(ref e) => {
            state.write("case ");
            show_hir_expr(state, e);
            state.write(":\n");
        }
        hir::CaseLabel::Def => {
            state.write("default:\n");
        }
    }
}

pub fn show_iteration_statement(state: &mut OutputState, ist: &hir::IterationStatement) {
    show_indent(state);
    match *ist {
        hir::IterationStatement::While(ref cond, ref body) => {
            state.write("while (");
            show_condition(state, cond);
            state.write(") ");
            show_statement(state, body);
        }
        hir::IterationStatement::DoWhile(ref body, ref cond) => {
            state.write("do ");
            show_statement(state, body);
            state.write(" while (");
            show_hir_expr(state, cond);
            state.write(");\n");
        }
        hir::IterationStatement::For(ref init, ref rest, ref body) => {
            state.write("for (");
            show_for_init_statement(state, init);
            show_for_rest_statement(state, rest);
            state.write(") ");
            show_statement(state, body);
        }
    }
}

pub fn show_condition(state: &mut OutputState, c: &hir::Condition) {
    match *c {
        hir::Condition::Expr(ref e) => show_hir_expr(state, e),
        /*hir::Condition::Assignment(ref ty, ref name, ref initializer) => {
          show_type(state, ty);
          state.write(" ");
          show_identifier(f, name);
          state.write(" = ");
          show_initializer(state, initializer);
        }*/
    }
}

pub fn show_for_init_statement(state: &mut OutputState, i: &hir::ForInitStatement) {
    match *i {
        hir::ForInitStatement::Expression(ref expr) => {
            if let Some(ref e) = *expr {
                show_hir_expr(state, e);
            }
        }
        hir::ForInitStatement::Declaration(ref d) => {
            show_declaration(state, d);
        }
    }
}

pub fn show_for_rest_statement(state: &mut OutputState, r: &hir::ForRestStatement) {
    if let Some(ref cond) = r.condition {
        show_condition(state, cond);
    }

    state.write("; ");

    if let Some(ref e) = r.post_expr {
        show_hir_expr(state, e);
    }
}

fn use_return_mask(state: &OutputState) -> bool {
    if let Some(mask) = &state.mask {
        mask.kind != hir::ExprKind::CondMask
    } else {
        false
    }
}

pub fn show_jump_statement(state: &mut OutputState, j: &hir::JumpStatement) {
    show_indent(state);
    match *j {
        hir::JumpStatement::Continue => {
            state.write("continue;\n");
        }
        hir::JumpStatement::Break => {
            state.write("break;\n");
        }
        hir::JumpStatement::Discard => {
            if state.output_cxx {
                state.uses_discard = true;
                if let Some(mask) = &state.mask {
                    state.write("swgl_IsPixelDiscarded |= (");
                    show_hir_expr(state, mask);
                    state.write(")");
                    if state.return_declared {
                        state.write("&ret_mask");
                    }
                    state.write(";\n");
                } else {
                    state.write("swgl_IsPixelDiscarded = true;\n");
                }
            } else {
                state.write("discard;\n");
            }
        }
        hir::JumpStatement::Return(ref e) => {
            if let Some(e) = e {
                if state.output_cxx {
                    if use_return_mask(state) {
                        // We cast any conditions by `ret_mask_type` so that scalars nicely
                        // convert to -1. i.e. I32 &= bool will give the wrong result. while I32 &= I32(bool) works
                        let ret_mask_type = if state.return_vector {
                            "I32"
                        } else {
                            "int32_t"
                        };
                        if state.return_declared {
                            // XXX: the cloning here is bad
                            write!(state, "ret = if_then_else(ret_mask & {}(", ret_mask_type);
                            show_hir_expr(state, &state.mask.clone().unwrap());
                            state.write("), ");
                            show_hir_expr(state, e);
                            state.write(", ret);\n");
                        } else {
                            state.write("ret = ");
                            show_hir_expr(state, e);
                            state.write(";\n");
                        }

                        show_indent(state);

                        if state.return_declared {
                            write!(state, "ret_mask &= ~{}(", ret_mask_type);
                        } else {
                            write!(state, "ret_mask = ~{}(", ret_mask_type);
                        }
                        show_hir_expr(state, &state.mask.clone().unwrap());
                        state.write(");\n");
                        state.return_declared = true;
                    } else {
                        if state.return_declared {
                            state.write("ret = if_then_else(ret_mask, ");
                            show_hir_expr(state, e);
                            state.write(", ret);\n");
                        } else {
                            state.write("return ");
                            show_hir_expr(state, e);
                            state.write(";\n");
                        }
                    }
                } else {
                    state.write("return ");
                    show_hir_expr(state, e);
                    state.write(";\n");
                }
            } else {
                if state.output_cxx {
                    if use_return_mask(state) {
                        show_indent(state);
                        let ret_mask_type = if state.return_vector {
                            "I32"
                        } else {
                            "int32_t"
                        };
                        if state.return_declared {
                            write!(state, "ret_mask &= ~{}(", ret_mask_type);
                        } else {
                            write!(state, "ret_mask = ~{}(", ret_mask_type);
                        }
                        show_hir_expr(state, &state.mask.clone().unwrap());
                        state.write(");\n");
                        state.return_declared = true;
                    } else {
                        state.write("return;\n");
                    }
                } else {
                    state.write("return;\n");
                }
            }
        }
    }
}

pub fn show_path(state: &OutputState, path: &syntax::Path) {
    match path {
        syntax::Path::Absolute(s) => {
            let _ = write!(state, "<{}>", s);
        }
        syntax::Path::Relative(s) => {
            let _ = write!(state, "\"{}\"", s);
        }
    }
}

pub fn show_preprocessor(state: &OutputState, pp: &syntax::Preprocessor) {
    match *pp {
        syntax::Preprocessor::Define(ref pd) => show_preprocessor_define(state, pd),
        syntax::Preprocessor::Else => show_preprocessor_else(state),
        syntax::Preprocessor::ElseIf(ref pei) => show_preprocessor_elseif(state, pei),
        syntax::Preprocessor::EndIf => show_preprocessor_endif(state),
        syntax::Preprocessor::Error(ref pe) => show_preprocessor_error(state, pe),
        syntax::Preprocessor::If(ref pi) => show_preprocessor_if(state, pi),
        syntax::Preprocessor::IfDef(ref pid) => show_preprocessor_ifdef(state, pid),
        syntax::Preprocessor::IfNDef(ref pind) => show_preprocessor_ifndef(state, pind),
        syntax::Preprocessor::Include(ref pi) => show_preprocessor_include(state, pi),
        syntax::Preprocessor::Line(ref pl) => show_preprocessor_line(state, pl),
        syntax::Preprocessor::Pragma(ref pp) => show_preprocessor_pragma(state, pp),
        syntax::Preprocessor::Undef(ref pu) => show_preprocessor_undef(state, pu),
        syntax::Preprocessor::Version(ref pv) => show_preprocessor_version(state, pv),
        syntax::Preprocessor::Extension(ref pe) => show_preprocessor_extension(state, pe),
    }
}

pub fn show_preprocessor_define(state: &OutputState, pd: &syntax::PreprocessorDefine) {
    match *pd {
        syntax::PreprocessorDefine::ObjectLike {
            ref ident,
            ref value,
        } => {
            let _ = write!(state, "#define {} {}\n", ident, value);
        }

        syntax::PreprocessorDefine::FunctionLike {
            ref ident,
            ref args,
            ref value,
        } => {
            let _ = write!(state, "#define {}(", ident);

            if !args.is_empty() {
                let _ = write!(state, "{}", &args[0]);

                for arg in &args[1 .. args.len()] {
                    let _ = write!(state, ", {}", arg);
                }
            }

            let _ = write!(state, ") {}\n", value);
        }
    }
}

pub fn show_preprocessor_else(state: &OutputState) {
    state.write("#else\n");
}

pub fn show_preprocessor_elseif(state: &OutputState, pei: &syntax::PreprocessorElseIf) {
    let _ = write!(state, "#elseif {}\n", pei.condition);
}

pub fn show_preprocessor_error(state: &OutputState, pe: &syntax::PreprocessorError) {
    let _ = writeln!(state, "#error {}", pe.message);
}

pub fn show_preprocessor_endif(state: &OutputState) {
    state.write("#endif\n");
}

pub fn show_preprocessor_if(state: &OutputState, pi: &syntax::PreprocessorIf) {
    let _ = write!(state, "#if {}\n", pi.condition);
}

pub fn show_preprocessor_ifdef(state: &OutputState, pid: &syntax::PreprocessorIfDef) {
    state.write("#ifdef ");
    show_identifier(state, &pid.ident);
    state.write("\n");
}

pub fn show_preprocessor_ifndef(state: &OutputState, pind: &syntax::PreprocessorIfNDef) {
    state.write("#ifndef ");
    show_identifier(state, &pind.ident);
    state.write("\n");
}

pub fn show_preprocessor_include(state: &OutputState, pi: &syntax::PreprocessorInclude) {
    state.write("#include ");
    show_path(state, &pi.path);
    state.write("\n");
}

pub fn show_preprocessor_line(state: &OutputState, pl: &syntax::PreprocessorLine) {
    let _ = write!(state, "#line {}", pl.line);
    if let Some(source_string_number) = pl.source_string_number {
        let _ = write!(state, " {}", source_string_number);
    }
    state.write("\n");
}

pub fn show_preprocessor_pragma(state: &OutputState, pp: &syntax::PreprocessorPragma) {
    let _ = writeln!(state, "#pragma {}", pp.command);
}

pub fn show_preprocessor_undef(state: &OutputState, pud: &syntax::PreprocessorUndef) {
    state.write("#undef ");
    show_identifier(state, &pud.name);
    state.write("\n");
}

pub fn show_preprocessor_version(state: &OutputState, pv: &syntax::PreprocessorVersion) {
    let _ = write!(state, "#version {}", pv.version);

    if let Some(ref profile) = pv.profile {
        match *profile {
            syntax::PreprocessorVersionProfile::Core => {
                state.write(" core");
            }
            syntax::PreprocessorVersionProfile::Compatibility => {
                state.write(" compatibility");
            }
            syntax::PreprocessorVersionProfile::ES => {
                state.write(" es");
            }
        }
    }

    state.write("\n");
}

pub fn show_preprocessor_extension(state: &OutputState, pe: &syntax::PreprocessorExtension) {
    state.write("#extension ");

    match pe.name {
        syntax::PreprocessorExtensionName::All => {
            state.write("all");
        }
        syntax::PreprocessorExtensionName::Specific(ref n) => {
            state.write(n);
        }
    }

    if let Some(ref behavior) = pe.behavior {
        match *behavior {
            syntax::PreprocessorExtensionBehavior::Require => {
                state.write(" : require");
            }
            syntax::PreprocessorExtensionBehavior::Enable => {
                state.write(" : enable");
            }
            syntax::PreprocessorExtensionBehavior::Warn => {
                state.write(" : warn");
            }
            syntax::PreprocessorExtensionBehavior::Disable => {
                state.write(" : disable");
            }
        }
    }

    state.write("\n");
}

pub fn show_external_declaration(state: &mut OutputState, ed: &hir::ExternalDeclaration) {
    match *ed {
        hir::ExternalDeclaration::Preprocessor(ref pp) => {
            if !state.output_cxx {
                show_preprocessor(state, pp)
            }
        }
        hir::ExternalDeclaration::FunctionDefinition(ref fd) => {
            if !state.output_cxx {
                show_function_definition(state, fd, !0)
            }
        }
        hir::ExternalDeclaration::Declaration(ref d) => show_declaration(state, d),
    }
}

pub fn show_cxx_function_definition(state: &mut OutputState, name: hir::SymRef, vector_mask: u32) {
    if let Some((ref fd, run_class)) = state.hir.function_definition(name) {
        state.vector_mask = vector_mask;
        state.return_vector = (vector_mask & (1 << 31)) != 0
            || match run_class {
                hir::RunClass::Scalar => false,
                hir::RunClass::Dependent(mask) => (mask & vector_mask) != 0,
                _ => true,
            };
        match state.functions.get(&(name, vector_mask)) {
            Some(true) => {}
            Some(false) => {
                show_function_prototype(state, &fd.prototype);
                state.functions.insert((name, vector_mask), true);
            }
            None => {
                state.functions.insert((name, vector_mask), false);
                let buffer = state.push_buffer();
                show_function_definition(state, fd, vector_mask);
                for (name, vector_mask) in state.deps.replace(Vec::new()) {
                    show_cxx_function_definition(state, name, vector_mask);
                }
                state.flush_buffer();
                state.pop_buffer(buffer);
                state.functions.insert((name, vector_mask), true);
            }
        }
    }
}

pub fn show_translation_unit(state: &mut OutputState, tu: &hir::TranslationUnit) {
    state.flush_buffer();

    for ed in &(tu.0).0 {
        show_external_declaration(state, ed);
        state.flush_buffer();
    }
    if state.output_cxx {
        for name in &["main", "swgl_drawSpanRGBA8", "swgl_drawSpanR8"] {
            if let Some(sym) = state.hir.lookup(name) {
                show_cxx_function_definition(state, sym, 0);
                state.flush_buffer();
            }
        }
    }
}

fn write_abi(state: &mut OutputState) {
    match state.kind {
        ShaderKind::Fragment => {
            state.write("static void run(FragmentShaderImpl* impl) {\n");
            state.write(" Self* self = (Self*)impl;\n");
            if state.uses_discard {
                state.write(" self->swgl_IsPixelDiscarded = false;\n");
            }
            state.write(" self->main();\n");
            state.write(" self->step_interp_inputs();\n");
            state.write("}\n");
            state.write("static void skip(FragmentShaderImpl* impl, int steps) {\n");
            state.write(" Self* self = (Self*)impl;\n");
            state.write(" self->step_interp_inputs(steps);\n");
            state.write("}\n");
            if state.use_perspective {
                state.write("static void run_perspective(FragmentShaderImpl* impl) {\n");
                state.write(" Self* self = (Self*)impl;\n");
                if state.uses_discard {
                    state.write(" self->swgl_IsPixelDiscarded = false;\n");
                }
                state.write(" self->main();\n");
                state.write(" self->step_perspective_inputs();\n");
                state.write("}\n");
                state.write("static void skip_perspective(FragmentShaderImpl* impl, int steps) {\n");
                state.write(" Self* self = (Self*)impl;\n");
                state.write(" self->step_perspective_inputs(steps);\n");
                state.write("}\n");
            }
            if state.hir.lookup("swgl_drawSpanRGBA8").is_some() {
                state.write("static int draw_span_RGBA8(FragmentShaderImpl* impl) {\n");
                state.write(" Self* self = (Self*)impl; DISPATCH_DRAW_SPAN(self, RGBA8); }\n");
            }
            if state.hir.lookup("swgl_drawSpanR8").is_some() {
                state.write("static int draw_span_R8(FragmentShaderImpl* impl) {\n");
                state.write(" Self* self = (Self*)impl; DISPATCH_DRAW_SPAN(self, R8); }\n");
            }

            write!(state, "public:\n{}_frag() {{\n", state.name);
        }
        ShaderKind::Vertex => {
            state.write("static void run(VertexShaderImpl* impl, char* interps, size_t interp_stride) {\n");
            state.write(" Self* self = (Self*)impl;\n");
            state.write(" self->main();\n");
            state.write(" self->store_interp_outputs(interps, interp_stride);\n");
            state.write("}\n");
            state.write("static void init_batch(VertexShaderImpl* impl) {\n");
            state.write(" Self* self = (Self*)impl; self->bind_textures(); }\n");

            write!(state, "public:\n{}_vert() {{\n", state.name);
        }
    }
    match state.kind {
        ShaderKind::Fragment => {
            state.write(" init_span_func = &read_interp_inputs;\n");
            state.write(" run_func = &run;\n");
            state.write(" skip_func = &skip;\n");
            if state.hir.lookup("swgl_drawSpanRGBA8").is_some() {
                state.write(" draw_span_RGBA8_func = &draw_span_RGBA8;\n");
            }
            if state.hir.lookup("swgl_drawSpanR8").is_some() {
                state.write(" draw_span_R8_func = &draw_span_R8;\n");
            }
            if state.uses_discard {
                state.write(" enable_discard();\n");
            }
            if state.use_perspective {
                state.write(" enable_perspective();\n");
                state.write(" init_span_w_func = &read_perspective_inputs;\n");
                state.write(" run_w_func = &run_perspective;\n");
                state.write(" skip_w_func = &skip_perspective;\n");
            } else {
                state.write(" init_span_w_func = &read_interp_inputs;\n");
                state.write(" run_w_func = &run;\n");
                state.write(" skip_w_func = &skip;\n");
            }
        }
        ShaderKind::Vertex => {
            state.write(" set_uniform_1i_func = &set_uniform_1i;\n");
            state.write(" set_uniform_4fv_func = &set_uniform_4fv;\n");
            state.write(" set_uniform_matrix4fv_func = &set_uniform_matrix4fv;\n");
            state.write(" init_batch_func = &init_batch;\n");
            state.write(" load_attribs_func = &load_attribs;\n");
            state.write(" run_primitive_func = &run;\n");
            if state.hir.used_clip_dist != 0 {
                state.write(" enable_clip_distance();\n");
            }
        }
    }
    state.write("}\n");
}

pub fn define_global_consts(state: &mut OutputState, tu: &hir::TranslationUnit, part_name: &str) {
    for i in tu {
        match i {
            hir::ExternalDeclaration::Declaration(hir::Declaration::InitDeclaratorList(ref d)) => {
                let sym = state.hir.sym(d.head.name);
                match &sym.decl {
                    hir::SymDecl::Global(hir::StorageClass::Const, ..) => {
                        let is_scalar = state.is_scalar.replace(
                            symbol_run_class(&sym.decl, state.vector_mask) == hir::RunClass::Scalar,
                        );
                        if let Some(ref _array) = d.head.ty.array_sizes {
                            show_type(state, &d.head.ty);
                        } else {
                            if let Some(ty_def) = d.head.ty_def {
                                show_sym_decl(state, &ty_def);
                            } else {
                                show_type(state, &d.head.ty);
                            }
                        }
                        write!(state, " constexpr {}::{};\n", part_name, sym.name);
                        state.is_scalar.set(is_scalar);
                    }
                    _ => {}
                }
            }
            _ => {}
        }
    }
}