Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1695 insertions, 0 deletions

diff --git a/third_party/rust/naga/src/back/spv/writer.rs b/third_party/rust/naga/src/back/spv/writer.rs
new file mode 100644
index 0000000000..59fe739f2c
--- /dev/null
+++ b/third_party/rust/naga/src/back/spv/writer.rs
@@ -0,0 +1,1695 @@
+use super::{
+    helpers::{contains_builtin, global_needs_wrapper, map_storage_class},
+    make_local, Block, BlockContext, CachedExpressions, EntryPointContext, Error, Function,
+    FunctionArgument, GlobalVariable, IdGenerator, Instruction, LocalType, LocalVariable,
+    LogicalLayout, LookupFunctionType, LookupType, LoopContext, Options, PhysicalLayout,
+    PipelineOptions, ResultMember, Writer, WriterFlags, BITS_PER_BYTE,
+};
+use crate::{
+    arena::{Handle, UniqueArena},
+    back::spv::BindingInfo,
+    proc::{Alignment, TypeResolution},
+    valid::{FunctionInfo, ModuleInfo},
+};
+use spirv::Word;
+use std::collections::hash_map::Entry;
+
+struct FunctionInterface<'a> {
+    varying_ids: &'a mut Vec<Word>,
+    stage: crate::ShaderStage,
+}
+
+impl Function {
+    fn to_words(&self, sink: &mut impl Extend<Word>) {
+        self.signature.as_ref().unwrap().to_words(sink);
+        for argument in self.parameters.iter() {
+            argument.instruction.to_words(sink);
+        }
+        for (index, block) in self.blocks.iter().enumerate() {
+            Instruction::label(block.label_id).to_words(sink);
+            if index == 0 {
+                for local_var in self.variables.values() {
+                    local_var.instruction.to_words(sink);
+                }
+            }
+            for instruction in block.body.iter() {
+                instruction.to_words(sink);
+            }
+        }
+    }
+}
+
+impl Writer {
+    pub fn new(options: &Options) -> Result<Self, Error> {
+        let (major, minor) = options.lang_version;
+        if major != 1 {
+            return Err(Error::UnsupportedVersion(major, minor));
+        }
+        let raw_version = ((major as u32) << 16) | ((minor as u32) << 8);
+
+        let mut capabilities_used = crate::FastHashSet::default();
+        capabilities_used.insert(spirv::Capability::Shader);
+
+        let mut id_gen = IdGenerator::default();
+        let gl450_ext_inst_id = id_gen.next();
+        let void_type = id_gen.next();
+
+        Ok(Writer {
+            physical_layout: PhysicalLayout::new(raw_version),
+            logical_layout: LogicalLayout::default(),
+            id_gen,
+            capabilities_available: options.capabilities.clone(),
+            capabilities_used,
+            extensions_used: crate::FastHashSet::default(),
+            debugs: vec![],
+            annotations: vec![],
+            flags: options.flags,
+            bounds_check_policies: options.bounds_check_policies,
+            void_type,
+            lookup_type: crate::FastHashMap::default(),
+            lookup_function: crate::FastHashMap::default(),
+            lookup_function_type: crate::FastHashMap::default(),
+            constant_ids: Vec::new(),
+            cached_constants: crate::FastHashMap::default(),
+            global_variables: Vec::new(),
+            binding_map: options.binding_map.clone(),
+            saved_cached: CachedExpressions::default(),
+            gl450_ext_inst_id,
+            temp_list: Vec::new(),
+        })
+    }
+
+    /// Reset `Writer` to its initial state, retaining any allocations.
+    ///
+    /// Why not just implement `Recyclable` for `Writer`? By design,
+    /// `Recyclable::recycle` requires ownership of the value, not just
+    /// `&mut`; see the trait documentation. But we need to use this method
+    /// from functions like `Writer::write`, which only have `&mut Writer`.
+    /// Workarounds include unsafe code (`std::ptr::read`, then `write`, ugh)
+    /// or something like a `Default` impl that returns an oddly-initialized
+    /// `Writer`, which is worse.
+    fn reset(&mut self) {
+        use super::recyclable::Recyclable;
+        use std::mem::take;
+
+        let mut id_gen = IdGenerator::default();
+        let gl450_ext_inst_id = id_gen.next();
+        let void_type = id_gen.next();
+
+        // Every field of the old writer that is not determined by the `Options`
+        // passed to `Writer::new` should be reset somehow.
+        let fresh = Writer {
+            // Copied from the old Writer:
+            flags: self.flags,
+            bounds_check_policies: self.bounds_check_policies,
+            capabilities_available: take(&mut self.capabilities_available),
+            binding_map: take(&mut self.binding_map),
+
+            // Initialized afresh:
+            id_gen,
+            void_type,
+            gl450_ext_inst_id,
+
+            // Recycled:
+            capabilities_used: take(&mut self.capabilities_used).recycle(),
+            extensions_used: take(&mut self.extensions_used).recycle(),
+            physical_layout: self.physical_layout.clone().recycle(),
+            logical_layout: take(&mut self.logical_layout).recycle(),
+            debugs: take(&mut self.debugs).recycle(),
+            annotations: take(&mut self.annotations).recycle(),
+            lookup_type: take(&mut self.lookup_type).recycle(),
+            lookup_function: take(&mut self.lookup_function).recycle(),
+            lookup_function_type: take(&mut self.lookup_function_type).recycle(),
+            constant_ids: take(&mut self.constant_ids).recycle(),
+            cached_constants: take(&mut self.cached_constants).recycle(),
+            global_variables: take(&mut self.global_variables).recycle(),
+            saved_cached: take(&mut self.saved_cached).recycle(),
+            temp_list: take(&mut self.temp_list).recycle(),
+        };
+
+        *self = fresh;
+
+        self.capabilities_used.insert(spirv::Capability::Shader);
+    }
+
+    /// Indicate that the code requires any one of the listed capabilities.
+    ///
+    /// If nothing in `capabilities` appears in the available capabilities
+    /// specified in the [`Options`] from which this `Writer` was created,
+    /// return an error. The `what` string is used in the error message to
+    /// explain what provoked the requirement. (If no available capabilities were
+    /// given, assume everything is available.)
+    ///
+    /// The first acceptable capability will be added to this `Writer`'s
+    /// [`capabilities_used`] table, and an `OpCapability` emitted for it in the
+    /// result. For this reason, more specific capabilities should be listed
+    /// before more general.
+    ///
+    /// [`capabilities_used`]: Writer::capabilities_used
+    pub(super) fn require_any(
+        &mut self,
+        what: &'static str,
+        capabilities: &[spirv::Capability],
+    ) -> Result<(), Error> {
+        match *capabilities {
+            [] => Ok(()),
+            [first, ..] => {
+                // Find the first acceptable capability, or return an error if
+                // there is none.
+                let selected = match self.capabilities_available {
+                    None => first,
+                    Some(ref available) => {
+                        match capabilities.iter().find(|cap| available.contains(cap)) {
+                            Some(&cap) => cap,
+                            None => {
+                                return Err(Error::MissingCapabilities(what, capabilities.to_vec()))
+                            }
+                        }
+                    }
+                };
+                self.capabilities_used.insert(selected);
+                Ok(())
+            }
+        }
+    }
+
+    /// Indicate that the code uses the given extension.
+    pub(super) fn use_extension(&mut self, extension: &'static str) {
+        self.extensions_used.insert(extension);
+    }
+
+    pub(super) fn get_type_id(&mut self, lookup_ty: LookupType) -> Word {
+        match self.lookup_type.entry(lookup_ty) {
+            Entry::Occupied(e) => *e.get(),
+            Entry::Vacant(e) => {
+                let local = match lookup_ty {
+                    LookupType::Handle(_handle) => unreachable!("Handles are populated at start"),
+                    LookupType::Local(local) => local,
+                };
+
+                let id = self.id_gen.next();
+                e.insert(id);
+                self.write_type_declaration_local(id, local);
+                id
+            }
+        }
+    }
+
+    pub(super) fn get_expression_type_id(&mut self, tr: &TypeResolution) -> Word {
+        let lookup_ty = match *tr {
+            TypeResolution::Handle(ty_handle) => LookupType::Handle(ty_handle),
+            TypeResolution::Value(ref inner) => LookupType::Local(make_local(inner).unwrap()),
+        };
+        self.get_type_id(lookup_ty)
+    }
+
+    pub(super) fn get_pointer_id(
+        &mut self,
+        arena: &UniqueArena<crate::Type>,
+        handle: Handle<crate::Type>,
+        class: spirv::StorageClass,
+    ) -> Result<Word, Error> {
+        let ty_id = self.get_type_id(LookupType::Handle(handle));
+        if let crate::TypeInner::Pointer { .. } = arena[handle].inner {
+            return Ok(ty_id);
+        }
+        let lookup_type = LookupType::Local(LocalType::Pointer {
+            base: handle,
+            class,
+        });
+        Ok(if let Some(&id) = self.lookup_type.get(&lookup_type) {
+            id
+        } else {
+            let id = self.id_gen.next();
+            let instruction = Instruction::type_pointer(id, class, ty_id);
+            instruction.to_words(&mut self.logical_layout.declarations);
+            self.lookup_type.insert(lookup_type, id);
+            id
+        })
+    }
+
+    pub(super) fn get_uint_type_id(&mut self) -> Word {
+        let local_type = LocalType::Value {
+            vector_size: None,
+            kind: crate::ScalarKind::Uint,
+            width: 4,
+            pointer_space: None,
+        };
+        self.get_type_id(local_type.into())
+    }
+
+    pub(super) fn get_float_type_id(&mut self) -> Word {
+        let local_type = LocalType::Value {
+            vector_size: None,
+            kind: crate::ScalarKind::Float,
+            width: 4,
+            pointer_space: None,
+        };
+        self.get_type_id(local_type.into())
+    }
+
+    pub(super) fn get_float_pointer_type_id(&mut self, class: spirv::StorageClass) -> Word {
+        let lookup_type = LookupType::Local(LocalType::Value {
+            vector_size: None,
+            kind: crate::ScalarKind::Float,
+            width: 4,
+            pointer_space: Some(class),
+        });
+        if let Some(&id) = self.lookup_type.get(&lookup_type) {
+            id
+        } else {
+            let id = self.id_gen.next();
+            let ty_id = self.get_float_type_id();
+            let instruction = Instruction::type_pointer(id, class, ty_id);
+            instruction.to_words(&mut self.logical_layout.declarations);
+            self.lookup_type.insert(lookup_type, id);
+            id
+        }
+    }
+
+    pub(super) fn get_bool_type_id(&mut self) -> Word {
+        let local_type = LocalType::Value {
+            vector_size: None,
+            kind: crate::ScalarKind::Bool,
+            width: 1,
+            pointer_space: None,
+        };
+        self.get_type_id(local_type.into())
+    }
+
+    pub(super) fn decorate(&mut self, id: Word, decoration: spirv::Decoration, operands: &[Word]) {
+        self.annotations
+            .push(Instruction::decorate(id, decoration, operands));
+    }
+
+    fn write_function(
+        &mut self,
+        ir_function: &crate::Function,
+        info: &FunctionInfo,
+        ir_module: &crate::Module,
+        mut interface: Option<FunctionInterface>,
+    ) -> Result<Word, Error> {
+        let mut function = Function::default();
+
+        for (handle, variable) in ir_function.local_variables.iter() {
+            let id = self.id_gen.next();
+
+            if self.flags.contains(WriterFlags::DEBUG) {
+                if let Some(ref name) = variable.name {
+                    self.debugs.push(Instruction::name(id, name));
+                }
+            }
+
+            let init_word = variable
+                .init
+                .map(|constant| self.constant_ids[constant.index()]);
+            let pointer_type_id =
+                self.get_pointer_id(&ir_module.types, variable.ty, spirv::StorageClass::Function)?;
+            let instruction = Instruction::variable(
+                pointer_type_id,
+                id,
+                spirv::StorageClass::Function,
+                init_word.or_else(|| {
+                    let type_id = self.get_type_id(LookupType::Handle(variable.ty));
+                    Some(self.write_constant_null(type_id))
+                }),
+            );
+            function
+                .variables
+                .insert(handle, LocalVariable { id, instruction });
+        }
+
+        let prelude_id = self.id_gen.next();
+        let mut prelude = Block::new(prelude_id);
+        let mut ep_context = EntryPointContext {
+            argument_ids: Vec::new(),
+            results: Vec::new(),
+        };
+
+        let mut parameter_type_ids = Vec::with_capacity(ir_function.arguments.len());
+        for argument in ir_function.arguments.iter() {
+            let class = spirv::StorageClass::Input;
+            let handle_ty = ir_module.types[argument.ty].inner.is_handle();
+            let argument_type_id = match handle_ty {
+                true => self.get_pointer_id(
+                    &ir_module.types,
+                    argument.ty,
+                    spirv::StorageClass::UniformConstant,
+                )?,
+                false => self.get_type_id(LookupType::Handle(argument.ty)),
+            };
+
+            if let Some(ref mut iface) = interface {
+                let id = if let Some(ref binding) = argument.binding {
+                    let name = argument.name.as_deref();
+
+                    let varying_id = self.write_varying(
+                        ir_module,
+                        iface.stage,
+                        class,
+                        name,
+                        argument.ty,
+                        binding,
+                    )?;
+                    iface.varying_ids.push(varying_id);
+                    let id = self.id_gen.next();
+                    prelude
+                        .body
+                        .push(Instruction::load(argument_type_id, id, varying_id, None));
+                    id
+                } else if let crate::TypeInner::Struct { ref members, .. } =
+                    ir_module.types[argument.ty].inner
+                {
+                    let struct_id = self.id_gen.next();
+                    let mut constituent_ids = Vec::with_capacity(members.len());
+                    for member in members {
+                        let type_id = self.get_type_id(LookupType::Handle(member.ty));
+                        let name = member.name.as_deref();
+                        let binding = member.binding.as_ref().unwrap();
+                        let varying_id = self.write_varying(
+                            ir_module,
+                            iface.stage,
+                            class,
+                            name,
+                            member.ty,
+                            binding,
+                        )?;
+                        iface.varying_ids.push(varying_id);
+                        let id = self.id_gen.next();
+                        prelude
+                            .body
+                            .push(Instruction::load(type_id, id, varying_id, None));
+                        constituent_ids.push(id);
+                    }
+                    prelude.body.push(Instruction::composite_construct(
+                        argument_type_id,
+                        struct_id,
+                        &constituent_ids,
+                    ));
+                    struct_id
+                } else {
+                    unreachable!("Missing argument binding on an entry point");
+                };
+                ep_context.argument_ids.push(id);
+            } else {
+                let argument_id = self.id_gen.next();
+                let instruction = Instruction::function_parameter(argument_type_id, argument_id);
+                if self.flags.contains(WriterFlags::DEBUG) {
+                    if let Some(ref name) = argument.name {
+                        self.debugs.push(Instruction::name(argument_id, name));
+                    }
+                }
+                function.parameters.push(FunctionArgument {
+                    instruction,
+                    handle_id: if handle_ty {
+                        let id = self.id_gen.next();
+                        prelude.body.push(Instruction::load(
+                            self.get_type_id(LookupType::Handle(argument.ty)),
+                            id,
+                            argument_id,
+                            None,
+                        ));
+                        id
+                    } else {
+                        0
+                    },
+                });
+                parameter_type_ids.push(argument_type_id);
+            };
+        }
+
+        let return_type_id = match ir_function.result {
+            Some(ref result) => {
+                if let Some(ref mut iface) = interface {
+                    let mut has_point_size = false;
+                    let class = spirv::StorageClass::Output;
+                    if let Some(ref binding) = result.binding {
+                        has_point_size |=
+                            *binding == crate::Binding::BuiltIn(crate::BuiltIn::PointSize);
+                        let type_id = self.get_type_id(LookupType::Handle(result.ty));
+                        let varying_id = self.write_varying(
+                            ir_module,
+                            iface.stage,
+                            class,
+                            None,
+                            result.ty,
+                            binding,
+                        )?;
+                        iface.varying_ids.push(varying_id);
+                        ep_context.results.push(ResultMember {
+                            id: varying_id,
+                            type_id,
+                            built_in: binding.to_built_in(),
+                        });
+                    } else if let crate::TypeInner::Struct { ref members, .. } =
+                        ir_module.types[result.ty].inner
+                    {
+                        for member in members {
+                            let type_id = self.get_type_id(LookupType::Handle(member.ty));
+                            let name = member.name.as_deref();
+                            let binding = member.binding.as_ref().unwrap();
+                            has_point_size |=
+                                *binding == crate::Binding::BuiltIn(crate::BuiltIn::PointSize);
+                            let varying_id = self.write_varying(
+                                ir_module,
+                                iface.stage,
+                                class,
+                                name,
+                                member.ty,
+                                binding,
+                            )?;
+                            iface.varying_ids.push(varying_id);
+                            ep_context.results.push(ResultMember {
+                                id: varying_id,
+                                type_id,
+                                built_in: binding.to_built_in(),
+                            });
+                        }
+                    } else {
+                        unreachable!("Missing result binding on an entry point");
+                    }
+
+                    if self.flags.contains(WriterFlags::FORCE_POINT_SIZE)
+                        && iface.stage == crate::ShaderStage::Vertex
+                        && !has_point_size
+                    {
+                        // add point size artificially
+                        let varying_id = self.id_gen.next();
+                        let pointer_type_id = self.get_float_pointer_type_id(class);
+                        Instruction::variable(pointer_type_id, varying_id, class, None)
+                            .to_words(&mut self.logical_layout.declarations);
+                        self.decorate(
+                            varying_id,
+                            spirv::Decoration::BuiltIn,
+                            &[spirv::BuiltIn::PointSize as u32],
+                        );
+                        iface.varying_ids.push(varying_id);
+
+                        let default_value_id =
+                            self.get_constant_scalar(crate::ScalarValue::Float(1.0), 4);
+                        prelude
+                            .body
+                            .push(Instruction::store(varying_id, default_value_id, None));
+                    }
+                    self.void_type
+                } else {
+                    self.get_type_id(LookupType::Handle(result.ty))
+                }
+            }
+            None => self.void_type,
+        };
+
+        let lookup_function_type = LookupFunctionType {
+            parameter_type_ids,
+            return_type_id,
+        };
+
+        let function_id = self.id_gen.next();
+        if self.flags.contains(WriterFlags::DEBUG) {
+            if let Some(ref name) = ir_function.name {
+                self.debugs.push(Instruction::name(function_id, name));
+            }
+        }
+
+        let function_type = self.get_function_type(lookup_function_type);
+        function.signature = Some(Instruction::function(
+            return_type_id,
+            function_id,
+            spirv::FunctionControl::empty(),
+            function_type,
+        ));
+
+        if interface.is_some() {
+            function.entry_point_context = Some(ep_context);
+        }
+
+        // fill up the `GlobalVariable::access_id`
+        for gv in self.global_variables.iter_mut() {
+            gv.reset_for_function();
+        }
+        for (handle, var) in ir_module.global_variables.iter() {
+            if info[handle].is_empty() {
+                continue;
+            }
+
+            let mut gv = self.global_variables[handle.index()].clone();
+
+            // Handle globals are pre-emitted and should be loaded automatically.
+            //
+            // Any that are binding arrays we skip as we cannot load the array, we must load the result after indexing.
+            let is_binding_array = match ir_module.types[var.ty].inner {
+                crate::TypeInner::BindingArray { .. } => true,
+                _ => false,
+            };
+
+            if var.space == crate::AddressSpace::Handle && !is_binding_array {
+                let var_type_id = self.get_type_id(LookupType::Handle(var.ty));
+                let id = self.id_gen.next();
+                prelude
+                    .body
+                    .push(Instruction::load(var_type_id, id, gv.var_id, None));
+                gv.access_id = gv.var_id;
+                gv.handle_id = id;
+            } else if global_needs_wrapper(ir_module, var) {
+                let class = map_storage_class(var.space);
+                let pointer_type_id = self.get_pointer_id(&ir_module.types, var.ty, class)?;
+                let index_id = self.get_index_constant(0);
+
+                let id = self.id_gen.next();
+                prelude.body.push(Instruction::access_chain(
+                    pointer_type_id,
+                    id,
+                    gv.var_id,
+                    &[index_id],
+                ));
+                gv.access_id = id;
+            } else {
+                // by default, the variable ID is accessed as is
+                gv.access_id = gv.var_id;
+            };
+
+            // work around borrow checking in the presence of `self.xxx()` calls
+            self.global_variables[handle.index()] = gv;
+        }
+
+        // Create a `BlockContext` for generating SPIR-V for the function's
+        // body.
+        let mut context = BlockContext {
+            ir_module,
+            ir_function,
+            fun_info: info,
+            function: &mut function,
+            // Re-use the cached expression table from prior functions.
+            cached: std::mem::take(&mut self.saved_cached),
+
+            // Steal the Writer's temp list for a bit.
+            temp_list: std::mem::take(&mut self.temp_list),
+            writer: self,
+        };
+
+        // fill up the pre-emitted expressions
+        context.cached.reset(ir_function.expressions.len());
+        for (handle, expr) in ir_function.expressions.iter() {
+            if expr.needs_pre_emit() {
+                context.cache_expression_value(handle, &mut prelude)?;
+            }
+        }
+
+        let main_id = context.gen_id();
+        context
+            .function
+            .consume(prelude, Instruction::branch(main_id));
+        context.write_block(
+            main_id,
+            &ir_function.body,
+            super::block::BlockExit::Return,
+            LoopContext::default(),
+        )?;
+
+        // Consume the `BlockContext`, ending its borrows and letting the
+        // `Writer` steal back its cached expression table and temp_list.
+        let BlockContext {
+            cached, temp_list, ..
+        } = context;
+        self.saved_cached = cached;
+        self.temp_list = temp_list;
+
+        function.to_words(&mut self.logical_layout.function_definitions);
+        Instruction::function_end().to_words(&mut self.logical_layout.function_definitions);
+
+        Ok(function_id)
+    }
+
+    fn write_execution_mode(
+        &mut self,
+        function_id: Word,
+        mode: spirv::ExecutionMode,
+    ) -> Result<(), Error> {
+        //self.check(mode.required_capabilities())?;
+        Instruction::execution_mode(function_id, mode, &[])
+            .to_words(&mut self.logical_layout.execution_modes);
+        Ok(())
+    }
+
+    // TODO Move to instructions module
+    fn write_entry_point(
+        &mut self,
+        entry_point: &crate::EntryPoint,
+        info: &FunctionInfo,
+        ir_module: &crate::Module,
+    ) -> Result<Instruction, Error> {
+        let mut interface_ids = Vec::new();
+        let function_id = self.write_function(
+            &entry_point.function,
+            info,
+            ir_module,
+            Some(FunctionInterface {
+                varying_ids: &mut interface_ids,
+                stage: entry_point.stage,
+            }),
+        )?;
+
+        let exec_model = match entry_point.stage {
+            crate::ShaderStage::Vertex => spirv::ExecutionModel::Vertex,
+            crate::ShaderStage::Fragment => {
+                self.write_execution_mode(function_id, spirv::ExecutionMode::OriginUpperLeft)?;
+                if let Some(ref result) = entry_point.function.result {
+                    if contains_builtin(
+                        result.binding.as_ref(),
+                        result.ty,
+                        &ir_module.types,
+                        crate::BuiltIn::FragDepth,
+                    ) {
+                        self.write_execution_mode(
+                            function_id,
+                            spirv::ExecutionMode::DepthReplacing,
+                        )?;
+                    }
+                }
+                spirv::ExecutionModel::Fragment
+            }
+            crate::ShaderStage::Compute => {
+                let execution_mode = spirv::ExecutionMode::LocalSize;
+                //self.check(execution_mode.required_capabilities())?;
+                Instruction::execution_mode(
+                    function_id,
+                    execution_mode,
+                    &entry_point.workgroup_size,
+                )
+                .to_words(&mut self.logical_layout.execution_modes);
+                spirv::ExecutionModel::GLCompute
+            }
+        };
+        //self.check(exec_model.required_capabilities())?;
+
+        Ok(Instruction::entry_point(
+            exec_model,
+            function_id,
+            &entry_point.name,
+            interface_ids.as_slice(),
+        ))
+    }
+
+    fn make_scalar(
+        &mut self,
+        id: Word,
+        kind: crate::ScalarKind,
+        width: crate::Bytes,
+    ) -> Instruction {
+        use crate::ScalarKind as Sk;
+
+        let bits = (width * BITS_PER_BYTE) as u32;
+        match kind {
+            Sk::Sint | Sk::Uint => {
+                let signedness = if kind == Sk::Sint {
+                    super::instructions::Signedness::Signed
+                } else {
+                    super::instructions::Signedness::Unsigned
+                };
+                let cap = match bits {
+                    8 => Some(spirv::Capability::Int8),
+                    16 => Some(spirv::Capability::Int16),
+                    64 => Some(spirv::Capability::Int64),
+                    _ => None,
+                };
+                if let Some(cap) = cap {
+                    self.capabilities_used.insert(cap);
+                }
+                Instruction::type_int(id, bits, signedness)
+            }
+            Sk::Float => {
+                if bits == 64 {
+                    self.capabilities_used.insert(spirv::Capability::Float64);
+                }
+                Instruction::type_float(id, bits)
+            }
+            Sk::Bool => Instruction::type_bool(id),
+        }
+    }
+
+    fn request_image_capabilities(&mut self, inner: &crate::TypeInner) -> Result<(), Error> {
+        if let crate::TypeInner::Image {
+            dim,
+            arrayed,
+            class,
+        } = *inner
+        {
+            let sampled = match class {
+                crate::ImageClass::Sampled { .. } => true,
+                crate::ImageClass::Depth { .. } => true,
+                crate::ImageClass::Storage { format, .. } => {
+                    self.request_image_format_capabilities(format.into())?;
+                    false
+                }
+            };
+
+            match dim {
+                crate::ImageDimension::D1 => {
+                    if sampled {
+                        self.require_any("sampled 1D images", &[spirv::Capability::Sampled1D])?;
+                    } else {
+                        self.require_any("1D storage images", &[spirv::Capability::Image1D])?;
+                    }
+                }
+                crate::ImageDimension::Cube if arrayed => {
+                    if sampled {
+                        self.require_any(
+                            "sampled cube array images",
+                            &[spirv::Capability::SampledCubeArray],
+                        )?;
+                    } else {
+                        self.require_any(
+                            "cube array storage images",
+                            &[spirv::Capability::ImageCubeArray],
+                        )?;
+                    }
+                }
+                _ => {}
+            }
+        }
+
+        Ok(())
+    }
+
+    fn write_type_declaration_local(&mut self, id: Word, local_ty: LocalType) {
+        let instruction = match local_ty {
+            LocalType::Value {
+                vector_size: None,
+                kind,
+                width,
+                pointer_space: None,
+            } => self.make_scalar(id, kind, width),
+            LocalType::Value {
+                vector_size: Some(size),
+                kind,
+                width,
+                pointer_space: None,
+            } => {
+                let scalar_id = self.get_type_id(LookupType::Local(LocalType::Value {
+                    vector_size: None,
+                    kind,
+                    width,
+                    pointer_space: None,
+                }));
+                Instruction::type_vector(id, scalar_id, size)
+            }
+            LocalType::Matrix {
+                columns,
+                rows,
+                width,
+            } => {
+                let vector_id = self.get_type_id(LookupType::Local(LocalType::Value {
+                    vector_size: Some(rows),
+                    kind: crate::ScalarKind::Float,
+                    width,
+                    pointer_space: None,
+                }));
+                Instruction::type_matrix(id, vector_id, columns)
+            }
+            LocalType::Pointer { base, class } => {
+                let type_id = self.get_type_id(LookupType::Handle(base));
+                Instruction::type_pointer(id, class, type_id)
+            }
+            LocalType::Value {
+                vector_size,
+                kind,
+                width,
+                pointer_space: Some(class),
+            } => {
+                let type_id = self.get_type_id(LookupType::Local(LocalType::Value {
+                    vector_size,
+                    kind,
+                    width,
+                    pointer_space: None,
+                }));
+                Instruction::type_pointer(id, class, type_id)
+            }
+            LocalType::Image(image) => {
+                let local_type = LocalType::Value {
+                    vector_size: None,
+                    kind: image.sampled_type,
+                    width: 4,
+                    pointer_space: None,
+                };
+                let type_id = self.get_type_id(LookupType::Local(local_type));
+                Instruction::type_image(id, type_id, image.dim, image.flags, image.image_format)
+            }
+            LocalType::Sampler => Instruction::type_sampler(id),
+            LocalType::SampledImage { image_type_id } => {
+                Instruction::type_sampled_image(id, image_type_id)
+            }
+            LocalType::BindingArray { base, size } => {
+                let inner_ty = self.get_type_id(LookupType::Handle(base));
+                let scalar_id = self.get_constant_scalar(crate::ScalarValue::Uint(size), 4);
+                Instruction::type_array(id, inner_ty, scalar_id)
+            }
+            LocalType::PointerToBindingArray { base, size } => {
+                let inner_ty =
+                    self.get_type_id(LookupType::Local(LocalType::BindingArray { base, size }));
+                Instruction::type_pointer(id, spirv::StorageClass::UniformConstant, inner_ty)
+            }
+        };
+
+        instruction.to_words(&mut self.logical_layout.declarations);
+    }
+
+    fn write_type_declaration_arena(
+        &mut self,
+        arena: &UniqueArena<crate::Type>,
+        handle: Handle<crate::Type>,
+    ) -> Result<Word, Error> {
+        let ty = &arena[handle];
+        let id = if let Some(local) = make_local(&ty.inner) {
+            // This type can be represented as a `LocalType`, so check if we've
+            // already written an instruction for it. If not, do so now, with
+            // `write_type_declaration_local`.
+            match self.lookup_type.entry(LookupType::Local(local)) {
+                // We already have an id for this `LocalType`.
+                Entry::Occupied(e) => *e.get(),
+
+                // It's a type we haven't seen before.
+                Entry::Vacant(e) => {
+                    let id = self.id_gen.next();
+                    e.insert(id);
+
+                    self.write_type_declaration_local(id, local);
+
+                    // If it's an image type, request SPIR-V capabilities here, so
+                    // write_type_declaration_local can stay infallible.
+                    self.request_image_capabilities(&ty.inner)?;
+
+                    id
+                }
+            }
+        } else {
+            use spirv::Decoration;
+
+            let id = self.id_gen.next();
+            let instruction = match ty.inner {
+                crate::TypeInner::Array { base, size, stride } => {
+                    self.decorate(id, Decoration::ArrayStride, &[stride]);
+
+                    let type_id = self.get_type_id(LookupType::Handle(base));
+                    match size {
+                        crate::ArraySize::Constant(const_handle) => {
+                            let length_id = self.constant_ids[const_handle.index()];
+                            Instruction::type_array(id, type_id, length_id)
+                        }
+                        crate::ArraySize::Dynamic => Instruction::type_runtime_array(id, type_id),
+                    }
+                }
+                crate::TypeInner::BindingArray { base, size } => {
+                    let type_id = self.get_type_id(LookupType::Handle(base));
+                    match size {
+                        crate::ArraySize::Constant(const_handle) => {
+                            let length_id = self.constant_ids[const_handle.index()];
+                            Instruction::type_array(id, type_id, length_id)
+                        }
+                        crate::ArraySize::Dynamic => Instruction::type_runtime_array(id, type_id),
+                    }
+                }
+                crate::TypeInner::Struct {
+                    ref members,
+                    span: _,
+                } => {
+                    let mut member_ids = Vec::with_capacity(members.len());
+                    for (index, member) in members.iter().enumerate() {
+                        self.decorate_struct_member(id, index, member, arena)?;
+                        let member_id = self.get_type_id(LookupType::Handle(member.ty));
+                        member_ids.push(member_id);
+                    }
+                    Instruction::type_struct(id, member_ids.as_slice())
+                }
+
+                // These all have TypeLocal representations, so they should have been
+                // handled by `write_type_declaration_local` above.
+                crate::TypeInner::Scalar { .. }
+                | crate::TypeInner::Atomic { .. }
+                | crate::TypeInner::Vector { .. }
+                | crate::TypeInner::Matrix { .. }
+                | crate::TypeInner::Pointer { .. }
+                | crate::TypeInner::ValuePointer { .. }
+                | crate::TypeInner::Image { .. }
+                | crate::TypeInner::Sampler { .. } => unreachable!(),
+            };
+
+            instruction.to_words(&mut self.logical_layout.declarations);
+            id
+        };
+
+        // Add this handle as a new alias for that type.
+        self.lookup_type.insert(LookupType::Handle(handle), id);
+
+        if self.flags.contains(WriterFlags::DEBUG) {
+            if let Some(ref name) = ty.name {
+                self.debugs.push(Instruction::name(id, name));
+            }
+        }
+
+        Ok(id)
+    }
+
+    fn request_image_format_capabilities(
+        &mut self,
+        format: spirv::ImageFormat,
+    ) -> Result<(), Error> {
+        use spirv::ImageFormat as If;
+        match format {
+            If::Rg32f
+            | If::Rg16f
+            | If::R11fG11fB10f
+            | If::R16f
+            | If::Rgba16
+            | If::Rgb10A2
+            | If::Rg16
+            | If::Rg8
+            | If::R16
+            | If::R8
+            | If::Rgba16Snorm
+            | If::Rg16Snorm
+            | If::Rg8Snorm
+            | If::R16Snorm
+            | If::R8Snorm
+            | If::Rg32i
+            | If::Rg16i
+            | If::Rg8i
+            | If::R16i
+            | If::R8i
+            | If::Rgb10a2ui
+            | If::Rg32ui
+            | If::Rg16ui
+            | If::Rg8ui
+            | If::R16ui
+            | If::R8ui => self.require_any(
+                "storage image format",
+                &[spirv::Capability::StorageImageExtendedFormats],
+            ),
+            If::R64ui | If::R64i => self.require_any(
+                "64-bit integer storage image format",
+                &[spirv::Capability::Int64ImageEXT],
+            ),
+            If::Unknown
+            | If::Rgba32f
+            | If::Rgba16f
+            | If::R32f
+            | If::Rgba8
+            | If::Rgba8Snorm
+            | If::Rgba32i
+            | If::Rgba16i
+            | If::Rgba8i
+            | If::R32i
+            | If::Rgba32ui
+            | If::Rgba16ui
+            | If::Rgba8ui
+            | If::R32ui => Ok(()),
+        }
+    }
+
+    pub(super) fn get_index_constant(&mut self, index: Word) -> Word {
+        self.get_constant_scalar(crate::ScalarValue::Uint(index as _), 4)
+    }
+
+    pub(super) fn get_constant_scalar(
+        &mut self,
+        value: crate::ScalarValue,
+        width: crate::Bytes,
+    ) -> Word {
+        if let Some(&id) = self.cached_constants.get(&(value, width)) {
+            return id;
+        }
+        let id = self.id_gen.next();
+        self.write_constant_scalar(id, &value, width, None);
+        self.cached_constants.insert((value, width), id);
+        id
+    }
+
+    fn write_constant_scalar(
+        &mut self,
+        id: Word,
+        value: &crate::ScalarValue,
+        width: crate::Bytes,
+        debug_name: Option<&String>,
+    ) {
+        if self.flags.contains(WriterFlags::DEBUG) {
+            if let Some(name) = debug_name {
+                self.debugs.push(Instruction::name(id, name));
+            }
+        }
+        let type_id = self.get_type_id(LookupType::Local(LocalType::Value {
+            vector_size: None,
+            kind: value.scalar_kind(),
+            width,
+            pointer_space: None,
+        }));
+        let (solo, pair);
+        let instruction = match *value {
+            crate::ScalarValue::Sint(val) => {
+                let words = match width {
+                    4 => {
+                        solo = [val as u32];
+                        &solo[..]
+                    }
+                    8 => {
+                        pair = [val as u32, (val >> 32) as u32];
+                        &pair
+                    }
+                    _ => unreachable!(),
+                };
+                Instruction::constant(type_id, id, words)
+            }
+            crate::ScalarValue::Uint(val) => {
+                let words = match width {
+                    4 => {
+                        solo = [val as u32];
+                        &solo[..]
+                    }
+                    8 => {
+                        pair = [val as u32, (val >> 32) as u32];
+                        &pair
+                    }
+                    _ => unreachable!(),
+                };
+                Instruction::constant(type_id, id, words)
+            }
+            crate::ScalarValue::Float(val) => {
+                let words = match width {
+                    4 => {
+                        solo = [(val as f32).to_bits()];
+                        &solo[..]
+                    }
+                    8 => {
+                        let bits = f64::to_bits(val);
+                        pair = [bits as u32, (bits >> 32) as u32];
+                        &pair
+                    }
+                    _ => unreachable!(),
+                };
+                Instruction::constant(type_id, id, words)
+            }
+            crate::ScalarValue::Bool(true) => Instruction::constant_true(type_id, id),
+            crate::ScalarValue::Bool(false) => Instruction::constant_false(type_id, id),
+        };
+
+        instruction.to_words(&mut self.logical_layout.declarations);
+    }
+
+    fn write_constant_composite(
+        &mut self,
+        id: Word,
+        ty: Handle<crate::Type>,
+        components: &[Handle<crate::Constant>],
+    ) -> Result<(), Error> {
+        let mut constituent_ids = Vec::with_capacity(components.len());
+        for constituent in components.iter() {
+            let constituent_id = self.constant_ids[constituent.index()];
+            constituent_ids.push(constituent_id);
+        }
+
+        let type_id = self.get_type_id(LookupType::Handle(ty));
+        Instruction::constant_composite(type_id, id, constituent_ids.as_slice())
+            .to_words(&mut self.logical_layout.declarations);
+        Ok(())
+    }
+
+    pub(super) fn write_constant_null(&mut self, type_id: Word) -> Word {
+        let null_id = self.id_gen.next();
+        Instruction::constant_null(type_id, null_id)
+            .to_words(&mut self.logical_layout.declarations);
+        null_id
+    }
+
+    /// Generate an `OpVariable` for one value in an [`EntryPoint`]'s IO interface.
+    ///
+    /// The [`Binding`]s of the arguments and result of an [`EntryPoint`]'s
+    /// [`Function`] describe a SPIR-V shader interface. In SPIR-V, the
+    /// interface is represented by global variables in the `Input` and `Output`
+    /// storage classes, with decorations indicating which builtin or location
+    /// each variable corresponds to.
+    ///
+    /// This function emits a single global `OpVariable` for a single value from
+    /// the interface, and adds appropriate decorations to indicate which
+    /// builtin or location it represents, how it should be interpolated, and so
+    /// on. The `class` argument gives the variable's SPIR-V storage class,
+    /// which should be either [`Input`] or [`Output`].
+    ///
+    /// [`Binding`]: crate::Binding
+    /// [`Function`]: crate::Function
+    /// [`EntryPoint`]: crate::EntryPoint
+    /// [`Input`]: spirv::StorageClass::Input
+    /// [`Output`]: spirv::StorageClass::Output
+    fn write_varying(
+        &mut self,
+        ir_module: &crate::Module,
+        stage: crate::ShaderStage,
+        class: spirv::StorageClass,
+        debug_name: Option<&str>,
+        ty: Handle<crate::Type>,
+        binding: &crate::Binding,
+    ) -> Result<Word, Error> {
+        let id = self.id_gen.next();
+        let pointer_type_id = self.get_pointer_id(&ir_module.types, ty, class)?;
+        Instruction::variable(pointer_type_id, id, class, None)
+            .to_words(&mut self.logical_layout.declarations);
+
+        if self
+            .flags
+            .contains(WriterFlags::DEBUG | WriterFlags::LABEL_VARYINGS)
+        {
+            if let Some(name) = debug_name {
+                self.debugs.push(Instruction::name(id, name));
+            }
+        }
+
+        use spirv::{BuiltIn, Decoration};
+
+        match *binding {
+            crate::Binding::Location {
+                location,
+                interpolation,
+                sampling,
+            } => {
+                self.decorate(id, Decoration::Location, &[location]);
+
+                // The Vulkan spec says: VUID-StandaloneSpirv-Flat-06202
+                //
+                // > The Flat, NoPerspective, Sample, and Centroid decorations
+                // > must not be used on variables with the Input storage class in
+                // > a vertex shader
+                if class != spirv::StorageClass::Input || stage != crate::ShaderStage::Vertex {
+                    match interpolation {
+                        // Perspective-correct interpolation is the default in SPIR-V.
+                        None | Some(crate::Interpolation::Perspective) => (),
+                        Some(crate::Interpolation::Flat) => {
+                            self.decorate(id, Decoration::Flat, &[]);
+                        }
+                        Some(crate::Interpolation::Linear) => {
+                            self.decorate(id, Decoration::NoPerspective, &[]);
+                        }
+                    }
+                }
+
+                match sampling {
+                    // Center sampling is the default in SPIR-V.
+                    None | Some(crate::Sampling::Center) => (),
+                    Some(crate::Sampling::Centroid) => {
+                        self.decorate(id, Decoration::Centroid, &[]);
+                    }
+                    Some(crate::Sampling::Sample) => {
+                        self.require_any(
+                            "per-sample interpolation",
+                            &[spirv::Capability::SampleRateShading],
+                        )?;
+                        self.decorate(id, Decoration::Sample, &[]);
+                    }
+                }
+            }
+            crate::Binding::BuiltIn(built_in) => {
+                use crate::BuiltIn as Bi;
+                let built_in = match built_in {
+                    Bi::Position { invariant } => {
+                        if invariant {
+                            self.decorate(id, Decoration::Invariant, &[]);
+                        }
+
+                        if class == spirv::StorageClass::Output {
+                            BuiltIn::Position
+                        } else {
+                            BuiltIn::FragCoord
+                        }
+                    }
+                    Bi::ViewIndex => {
+                        self.require_any("`view_index` built-in", &[spirv::Capability::MultiView])?;
+                        BuiltIn::ViewIndex
+                    }
+                    // vertex
+                    Bi::BaseInstance => BuiltIn::BaseInstance,
+                    Bi::BaseVertex => BuiltIn::BaseVertex,
+                    Bi::ClipDistance => BuiltIn::ClipDistance,
+                    Bi::CullDistance => BuiltIn::CullDistance,
+                    Bi::InstanceIndex => BuiltIn::InstanceIndex,
+                    Bi::PointSize => BuiltIn::PointSize,
+                    Bi::VertexIndex => BuiltIn::VertexIndex,
+                    // fragment
+                    Bi::FragDepth => BuiltIn::FragDepth,
+                    Bi::FrontFacing => BuiltIn::FrontFacing,
+                    Bi::PrimitiveIndex => {
+                        self.require_any(
+                            "`primitive_index` built-in",
+                            &[spirv::Capability::Geometry],
+                        )?;
+                        BuiltIn::PrimitiveId
+                    }
+                    Bi::SampleIndex => {
+                        self.require_any(
+                            "`sample_index` built-in",
+                            &[spirv::Capability::SampleRateShading],
+                        )?;
+
+                        BuiltIn::SampleId
+                    }
+                    Bi::SampleMask => BuiltIn::SampleMask,
+                    // compute
+                    Bi::GlobalInvocationId => BuiltIn::GlobalInvocationId,
+                    Bi::LocalInvocationId => BuiltIn::LocalInvocationId,
+                    Bi::LocalInvocationIndex => BuiltIn::LocalInvocationIndex,
+                    Bi::WorkGroupId => BuiltIn::WorkgroupId,
+                    Bi::WorkGroupSize => BuiltIn::WorkgroupSize,
+                    Bi::NumWorkGroups => BuiltIn::NumWorkgroups,
+                };
+
+                self.decorate(id, Decoration::BuiltIn, &[built_in as u32]);
+
+                use crate::ScalarKind as Sk;
+
+                // Per the Vulkan spec, `VUID-StandaloneSpirv-Flat-04744`:
+                //
+                // > Any variable with integer or double-precision floating-
+                // > point type and with Input storage class in a fragment
+                // > shader, must be decorated Flat
+                if class == spirv::StorageClass::Input && stage == crate::ShaderStage::Fragment {
+                    let is_flat = match ir_module.types[ty].inner {
+                        crate::TypeInner::Scalar { kind, .. }
+                        | crate::TypeInner::Vector { kind, .. } => match kind {
+                            Sk::Uint | Sk::Sint | Sk::Bool => true,
+                            Sk::Float => false,
+                        },
+                        _ => false,
+                    };
+
+                    if is_flat {
+                        self.decorate(id, Decoration::Flat, &[]);
+                    }
+                }
+            }
+        }
+
+        Ok(id)
+    }
+
+    fn write_global_variable(
+        &mut self,
+        ir_module: &crate::Module,
+        global_variable: &crate::GlobalVariable,
+    ) -> Result<Word, Error> {
+        use spirv::Decoration;
+
+        let id = self.id_gen.next();
+        let class = map_storage_class(global_variable.space);
+
+        //self.check(class.required_capabilities())?;
+
+        if self.flags.contains(WriterFlags::DEBUG) {
+            if let Some(ref name) = global_variable.name {
+                self.debugs.push(Instruction::name(id, name));
+            }
+        }
+
+        let storage_access = match global_variable.space {
+            crate::AddressSpace::Storage { access } => Some(access),
+            _ => match ir_module.types[global_variable.ty].inner {
+                crate::TypeInner::Image {
+                    class: crate::ImageClass::Storage { access, .. },
+                    ..
+                } => Some(access),
+                _ => None,
+            },
+        };
+        if let Some(storage_access) = storage_access {
+            if !storage_access.contains(crate::StorageAccess::LOAD) {
+                self.decorate(id, Decoration::NonReadable, &[]);
+            }
+            if !storage_access.contains(crate::StorageAccess::STORE) {
+                self.decorate(id, Decoration::NonWritable, &[]);
+            }
+        }
+
+        let mut substitute_inner_type_lookup = None;
+        if let Some(ref res_binding) = global_variable.binding {
+            self.decorate(id, Decoration::DescriptorSet, &[res_binding.group]);
+            self.decorate(id, Decoration::Binding, &[res_binding.binding]);
+
+            if let Some(&BindingInfo {
+                binding_array_size: Some(remapped_binding_array_size),
+            }) = self.binding_map.get(res_binding)
+            {
+                if let crate::TypeInner::BindingArray { base, .. } =
+                    ir_module.types[global_variable.ty].inner
+                {
+                    substitute_inner_type_lookup =
+                        Some(LookupType::Local(LocalType::PointerToBindingArray {
+                            base,
+                            size: remapped_binding_array_size as u64,
+                        }))
+                }
+            } else {
+            }
+        };
+
+        let init_word = global_variable
+            .init
+            .map(|constant| self.constant_ids[constant.index()]);
+        let inner_type_id = self.get_type_id(
+            substitute_inner_type_lookup.unwrap_or(LookupType::Handle(global_variable.ty)),
+        );
+
+        // generate the wrapping structure if needed
+        let pointer_type_id = if global_needs_wrapper(ir_module, global_variable) {
+            let wrapper_type_id = self.id_gen.next();
+
+            self.decorate(wrapper_type_id, Decoration::Block, &[]);
+            let member = crate::StructMember {
+                name: None,
+                ty: global_variable.ty,
+                binding: None,
+                offset: 0,
+            };
+            self.decorate_struct_member(wrapper_type_id, 0, &member, &ir_module.types)?;
+
+            Instruction::type_struct(wrapper_type_id, &[inner_type_id])
+                .to_words(&mut self.logical_layout.declarations);
+
+            let pointer_type_id = self.id_gen.next();
+            Instruction::type_pointer(pointer_type_id, class, wrapper_type_id)
+                .to_words(&mut self.logical_layout.declarations);
+
+            pointer_type_id
+        } else {
+            // This is a global variable in the Storage address space. The only
+            // way it could have `global_needs_wrapper() == false` is if it has
+            // a runtime-sized array. In this case, we need to decorate it with
+            // Block.
+            if let crate::AddressSpace::Storage { .. } = global_variable.space {
+                self.decorate(inner_type_id, Decoration::Block, &[]);
+            }
+            if substitute_inner_type_lookup.is_some() {
+                inner_type_id
+            } else {
+                self.get_pointer_id(&ir_module.types, global_variable.ty, class)?
+            }
+        };
+
+        let init_word = match global_variable.space {
+            crate::AddressSpace::Private => {
+                init_word.or_else(|| Some(self.write_constant_null(inner_type_id)))
+            }
+            _ => init_word,
+        };
+
+        Instruction::variable(pointer_type_id, id, class, init_word)
+            .to_words(&mut self.logical_layout.declarations);
+        Ok(id)
+    }
+
+    /// Write the necessary decorations for a struct member.
+    ///
+    /// Emit decorations for the `index`'th member of the struct type
+    /// designated by `struct_id`, described by `member`.
+    fn decorate_struct_member(
+        &mut self,
+        struct_id: Word,
+        index: usize,
+        member: &crate::StructMember,
+        arena: &UniqueArena<crate::Type>,
+    ) -> Result<(), Error> {
+        use spirv::Decoration;
+
+        self.annotations.push(Instruction::member_decorate(
+            struct_id,
+            index as u32,
+            Decoration::Offset,
+            &[member.offset],
+        ));
+
+        if self.flags.contains(WriterFlags::DEBUG) {
+            if let Some(ref name) = member.name {
+                self.debugs
+                    .push(Instruction::member_name(struct_id, index as u32, name));
+            }
+        }
+
+        // Matrices and arrays of matrices both require decorations,
+        // so "see through" an array to determine if they're needed.
+        let member_array_subty_inner = match arena[member.ty].inner {
+            crate::TypeInner::Array { base, .. } => &arena[base].inner,
+            ref other => other,
+        };
+        if let crate::TypeInner::Matrix {
+            columns: _,
+            rows,
+            width,
+        } = *member_array_subty_inner
+        {
+            let byte_stride = Alignment::from(rows) * width as u32;
+            self.annotations.push(Instruction::member_decorate(
+                struct_id,
+                index as u32,
+                Decoration::ColMajor,
+                &[],
+            ));
+            self.annotations.push(Instruction::member_decorate(
+                struct_id,
+                index as u32,
+                Decoration::MatrixStride,
+                &[byte_stride],
+            ));
+        }
+
+        Ok(())
+    }
+
+    fn get_function_type(&mut self, lookup_function_type: LookupFunctionType) -> Word {
+        match self
+            .lookup_function_type
+            .entry(lookup_function_type.clone())
+        {
+            Entry::Occupied(e) => *e.get(),
+            _ => {
+                let id = self.id_gen.next();
+                let instruction = Instruction::type_function(
+                    id,
+                    lookup_function_type.return_type_id,
+                    &lookup_function_type.parameter_type_ids,
+                );
+                instruction.to_words(&mut self.logical_layout.declarations);
+                self.lookup_function_type.insert(lookup_function_type, id);
+                id
+            }
+        }
+    }
+
+    fn write_physical_layout(&mut self) {
+        self.physical_layout.bound = self.id_gen.0 + 1;
+    }
+
+    fn write_logical_layout(
+        &mut self,
+        ir_module: &crate::Module,
+        mod_info: &ModuleInfo,
+        ep_index: Option<usize>,
+    ) -> Result<(), Error> {
+        fn has_view_index_check(
+            ir_module: &crate::Module,
+            binding: Option<&crate::Binding>,
+            ty: Handle<crate::Type>,
+        ) -> bool {
+            match ir_module.types[ty].inner {
+                crate::TypeInner::Struct { ref members, .. } => members.iter().any(|member| {
+                    has_view_index_check(ir_module, member.binding.as_ref(), member.ty)
+                }),
+                _ => binding == Some(&crate::Binding::BuiltIn(crate::BuiltIn::ViewIndex)),
+            }
+        }
+
+        let has_storage_buffers =
+            ir_module
+                .global_variables
+                .iter()
+                .any(|(_, var)| match var.space {
+                    crate::AddressSpace::Storage { .. } => true,
+                    _ => false,
+                });
+        let has_view_index = ir_module
+            .entry_points
+            .iter()
+            .flat_map(|entry| entry.function.arguments.iter())
+            .any(|arg| has_view_index_check(ir_module, arg.binding.as_ref(), arg.ty));
+
+        if self.physical_layout.version < 0x10300 && has_storage_buffers {
+            // enable the storage buffer class on < SPV-1.3
+            Instruction::extension("SPV_KHR_storage_buffer_storage_class")
+                .to_words(&mut self.logical_layout.extensions);
+        }
+        if has_view_index {
+            Instruction::extension("SPV_KHR_multiview")
+                .to_words(&mut self.logical_layout.extensions)
+        }
+        Instruction::type_void(self.void_type).to_words(&mut self.logical_layout.declarations);
+        Instruction::ext_inst_import(self.gl450_ext_inst_id, "GLSL.std.450")
+            .to_words(&mut self.logical_layout.ext_inst_imports);
+
+        if self.flags.contains(WriterFlags::DEBUG) {
+            self.debugs
+                .push(Instruction::source(spirv::SourceLanguage::GLSL, 450));
+        }
+
+        self.constant_ids.resize(ir_module.constants.len(), 0);
+        // first, output all the scalar constants
+        for (handle, constant) in ir_module.constants.iter() {
+            match constant.inner {
+                crate::ConstantInner::Composite { .. } => continue,
+                crate::ConstantInner::Scalar { width, ref value } => {
+                    self.constant_ids[handle.index()] = match constant.name {
+                        Some(ref name) => {
+                            let id = self.id_gen.next();
+                            self.write_constant_scalar(id, value, width, Some(name));
+                            id
+                        }
+                        None => self.get_constant_scalar(*value, width),
+                    };
+                }
+            }
+        }
+
+        // then all types, some of them may rely on constants and struct type set
+        for (handle, _) in ir_module.types.iter() {
+            self.write_type_declaration_arena(&ir_module.types, handle)?;
+        }
+
+        // the all the composite constants, they rely on types
+        for (handle, constant) in ir_module.constants.iter() {
+            match constant.inner {
+                crate::ConstantInner::Scalar { .. } => continue,
+                crate::ConstantInner::Composite { ty, ref components } => {
+                    let id = self.id_gen.next();
+                    self.constant_ids[handle.index()] = id;
+                    if self.flags.contains(WriterFlags::DEBUG) {
+                        if let Some(ref name) = constant.name {
+                            self.debugs.push(Instruction::name(id, name));
+                        }
+                    }
+                    self.write_constant_composite(id, ty, components)?;
+                }
+            }
+        }
+        debug_assert_eq!(self.constant_ids.iter().position(|&id| id == 0), None);
+
+        // now write all globals
+        for (handle, var) in ir_module.global_variables.iter() {
+            // If a single entry point was specified, only write `OpVariable` instructions
+            // for the globals it actually uses. Emit dummies for the others,
+            // to preserve the indices in `global_variables`.
+            let gvar = match ep_index {
+                Some(index) if mod_info.get_entry_point(index)[handle].is_empty() => {
+                    GlobalVariable::dummy()
+                }
+                _ => {
+                    let id = self.write_global_variable(ir_module, var)?;
+                    GlobalVariable::new(id)
+                }
+            };
+            self.global_variables.push(gvar);
+        }
+
+        // all functions
+        for (handle, ir_function) in ir_module.functions.iter() {
+            let info = &mod_info[handle];
+            if let Some(index) = ep_index {
+                let ep_info = mod_info.get_entry_point(index);
+                // If this function uses globals that we omitted from the SPIR-V
+                // because the entry point and its callees didn't use them,
+                // then we must skip it.
+                if !ep_info.dominates_global_use(info) {
+                    log::info!("Skip function {:?}", ir_function.name);
+                    continue;
+                }
+            }
+            let id = self.write_function(ir_function, info, ir_module, None)?;
+            self.lookup_function.insert(handle, id);
+        }
+
+        // and entry points
+        for (index, ir_ep) in ir_module.entry_points.iter().enumerate() {
+            if ep_index.is_some() && ep_index != Some(index) {
+                continue;
+            }
+            let info = mod_info.get_entry_point(index);
+            let ep_instruction = self.write_entry_point(ir_ep, info, ir_module)?;
+            ep_instruction.to_words(&mut self.logical_layout.entry_points);
+        }
+
+        for capability in self.capabilities_used.iter() {
+            Instruction::capability(*capability).to_words(&mut self.logical_layout.capabilities);
+        }
+        for extension in self.extensions_used.iter() {
+            Instruction::extension(extension).to_words(&mut self.logical_layout.extensions);
+        }
+        if ir_module.entry_points.is_empty() {
+            // SPIR-V doesn't like modules without entry points
+            Instruction::capability(spirv::Capability::Linkage)
+                .to_words(&mut self.logical_layout.capabilities);
+        }
+
+        let addressing_model = spirv::AddressingModel::Logical;
+        let memory_model = spirv::MemoryModel::GLSL450;
+        //self.check(addressing_model.required_capabilities())?;
+        //self.check(memory_model.required_capabilities())?;
+
+        Instruction::memory_model(addressing_model, memory_model)
+            .to_words(&mut self.logical_layout.memory_model);
+
+        if self.flags.contains(WriterFlags::DEBUG) {
+            for debug in self.debugs.iter() {
+                debug.to_words(&mut self.logical_layout.debugs);
+            }
+        }
+
+        for annotation in self.annotations.iter() {
+            annotation.to_words(&mut self.logical_layout.annotations);
+        }
+
+        Ok(())
+    }
+
+    pub fn write(
+        &mut self,
+        ir_module: &crate::Module,
+        info: &ModuleInfo,
+        pipeline_options: Option<&PipelineOptions>,
+        words: &mut Vec<Word>,
+    ) -> Result<(), Error> {
+        self.reset();
+
+        // Try to find the entry point and corresponding index
+        let ep_index = match pipeline_options {
+            Some(po) => {
+                let index = ir_module
+                    .entry_points
+                    .iter()
+                    .position(|ep| po.shader_stage == ep.stage && po.entry_point == ep.name)
+                    .ok_or(Error::EntryPointNotFound)?;
+                Some(index)
+            }
+            None => None,
+        };
+
+        self.write_logical_layout(ir_module, info, ep_index)?;
+        self.write_physical_layout();
+
+        self.physical_layout.in_words(words);
+        self.logical_layout.in_words(words);
+        Ok(())
+    }
+
+    /// Return the set of capabilities the last module written used.
+    pub const fn get_capabilities_used(&self) -> &crate::FastHashSet<spirv::Capability> {
+        &self.capabilities_used
+    }
+}
+
+#[test]
+fn test_write_physical_layout() {
+    let mut writer = Writer::new(&Options::default()).unwrap();
+    assert_eq!(writer.physical_layout.bound, 0);
+    writer.write_physical_layout();
+    assert_eq!(writer.physical_layout.bound, 3);
+}