feat!: Allow extension callbacks to have non-'static lifetimes (#128)

Closes #127.

BREAKING CHANGE: Add a lifetime argument to `TypingSession`,
`EmitModuleContext`, `EmitHugr`, `EmitFuncContext`.

src/custom.rs

@@ -111,7 +111,7 @@ impl<'a, H: HugrView + 'a> CodegenExtsBuilder<'a, H> {
         mut self,
         handler: impl 'a
             + for<'c> Fn(
-                &mut EmitFuncContext<'c, H>,
+                &mut EmitFuncContext<'c, 'a, H>,
                 EmitOpArgs<'c, '_, ExtensionOp, H>,
                 Op,
             ) -> Result<()>,
@@ -152,3 +152,73 @@ pub struct CodegenExtsMap<'a, H> {
     pub extension_op_handlers: Rc<ExtensionOpMap<'a, H>>,
     pub type_converter: Rc<TypeConverter<'a>>,
 }
+
+#[cfg(test)]
+mod test {
+    use hugr::{
+        extension::prelude::{ConstString, PRELUDE_ID, PRINT_OP_ID, STRING_TYPE, STRING_TYPE_NAME},
+        Hugr,
+    };
+    use inkwell::{
+        context::Context,
+        types::BasicType,
+        values::{BasicMetadataValueEnum, BasicValue},
+    };
+    use itertools::Itertools as _;
+
+    use crate::{emit::libc::emit_libc_printf, CodegenExtsBuilder};
+
+    #[test]
+    fn types_with_lifetimes() {
+        let n = "name_with_lifetime".to_string();
+
+        let cem = CodegenExtsBuilder::<Hugr>::default()
+            .custom_type((PRELUDE_ID, STRING_TYPE_NAME), |session, _| {
+                let ctx = session.iw_context();
+                Ok(ctx
+                    .get_struct_type(n.as_ref())
+                    .unwrap_or_else(|| ctx.opaque_struct_type(n.as_ref()))
+                    .as_basic_type_enum())
+            })
+            .finish();
+
+        let ctx = Context::create();
+
+        let ty = cem
+            .type_converter
+            .session(&ctx)
+            .llvm_type(&STRING_TYPE)
+            .unwrap()
+            .into_struct_type();
+        let ty_n = ty.get_name().unwrap().to_str().unwrap();
+        assert_eq!(ty_n, n);
+    }
+
+    #[test]
+    fn custom_const_lifetime_of_context() {
+        let ctx = Context::create();
+
+        let _ = CodegenExtsBuilder::<Hugr>::default()
+            .custom_const::<ConstString>(|_, konst| {
+                Ok(ctx
+                    .const_string(konst.value().as_bytes(), true)
+                    .as_basic_value_enum())
+            })
+            .finish();
+    }
+
+    #[test]
+    fn extension_op_lifetime() {
+        let ctx = Context::create();
+
+        let _ = CodegenExtsBuilder::<Hugr>::default()
+            .extension_op(PRELUDE_ID, PRINT_OP_ID, |context, args| {
+                let mut print_args: Vec<BasicMetadataValueEnum> =
+                    vec![ctx.const_string("%s".as_bytes(), true).into()];
+                print_args.extend(args.inputs.into_iter().map_into::<BasicMetadataValueEnum>());
+                emit_libc_printf(context, &print_args)?;
+                args.outputs.finish(context.builder(), [])
+            })
+            .finish();
+    }
+}

src/custom/extension_op.rs

@@ -35,15 +35,15 @@ use crate::emit::{EmitFuncContext, EmitOpArgs};
 ///
 /// Callbacks may hold references with lifetimes older than `'a`.
 pub trait ExtensionOpFn<'a, H>:
-    for<'c> Fn(&mut EmitFuncContext<'c, H>, EmitOpArgs<'c, '_, ExtensionOp, H>) -> Result<()> + 'a
+    for<'c> Fn(&mut EmitFuncContext<'c, 'a, H>, EmitOpArgs<'c, '_, ExtensionOp, H>) -> Result<()> + 'a
 {
 }
 
 impl<
         'a,
         H,
         F: for<'c> Fn(
-                &mut EmitFuncContext<'c, H>,
+                &mut EmitFuncContext<'c, 'a, H>,
                 EmitOpArgs<'c, '_, ExtensionOp, H>,
             ) -> Result<()>
             + ?Sized
@@ -76,7 +76,7 @@ impl<'a, H: HugrView> ExtensionOpMap<'a, H> {
         &mut self,
         handler: impl 'a
             + for<'c> Fn(
-                &mut EmitFuncContext<'c, H>,
+                &mut EmitFuncContext<'c, 'a, H>,
                 EmitOpArgs<'c, '_, ExtensionOp, H>,
                 Op,
             ) -> Result<()>,
@@ -96,7 +96,7 @@ impl<'a, H: HugrView> ExtensionOpMap<'a, H> {
     /// If no handler is registered for the op an error will be returned.
     pub fn emit_extension_op<'c>(
         &self,
-        context: &mut EmitFuncContext<'c, H>,
+        context: &mut EmitFuncContext<'c, 'a, H>,
         args: EmitOpArgs<'c, '_, ExtensionOp, H>,
     ) -> Result<()> {
         let node = args.node();

src/custom/load_constant.rs

@@ -19,15 +19,17 @@ use crate::emit::EmitFuncContext;
 ///
 /// Callbacks may hold references with lifetimes older than `'a`.
 pub trait LoadConstantFn<'a, H: ?Sized, CC: CustomConst + ?Sized>:
-    for<'c> Fn(&mut EmitFuncContext<'c, H>, &CC) -> Result<BasicValueEnum<'c>> + 'a
+    for<'c> Fn(&mut EmitFuncContext<'c, 'a, H>, &CC) -> Result<BasicValueEnum<'c>> + 'a
 {
 }
 
 impl<
         'a,
         H: ?Sized,
         CC: ?Sized + CustomConst,
-        F: 'a + ?Sized + for<'c> Fn(&mut EmitFuncContext<'c, H>, &CC) -> Result<BasicValueEnum<'c>>,
+        F: 'a
+            + ?Sized
+            + for<'c> Fn(&mut EmitFuncContext<'c, 'a, H>, &CC) -> Result<BasicValueEnum<'c>>,
     > LoadConstantFn<'a, H, CC> for F
 {
 }
@@ -59,7 +61,7 @@ impl<'a, H: HugrView> LoadConstantsMap<'a, H> {
     /// appropriate inner callbacks.
     pub fn emit_load_constant<'c>(
         &self,
-        context: &mut EmitFuncContext<'c, H>,
+        context: &mut EmitFuncContext<'c, 'a, H>,
         konst: &dyn CustomConst,
     ) -> Result<BasicValueEnum<'c>> {
         let type_id = konst.type_id();

src/custom/types.rs

@@ -1,3 +1,5 @@
+use std::marker::PhantomData;
+
 use itertools::Itertools as _;
 
 use hugr::types::CustomType;
@@ -14,22 +16,22 @@ use crate::{
 };
 
 pub trait LLVMCustomTypeFn<'a>:
-    for<'c> Fn(TypingSession<'c>, &CustomType) -> Result<BasicTypeEnum<'c>> + 'a
+    for<'c> Fn(TypingSession<'c, 'a>, &CustomType) -> Result<BasicTypeEnum<'c>> + 'a
 {
 }
 
 impl<
         'a,
-        F: for<'c> Fn(TypingSession<'c>, &CustomType) -> Result<BasicTypeEnum<'c>> + 'a + ?Sized,
+        F: for<'c> Fn(TypingSession<'c, 'a>, &CustomType) -> Result<BasicTypeEnum<'c>> + 'a + ?Sized,
     > LLVMCustomTypeFn<'a> for F
 {
 }
 
 #[derive(Default, Clone)]
-pub struct LLVMTypeMapping;
+pub struct LLVMTypeMapping<'a>(PhantomData<&'a ()>);
 
-impl TypeMapping for LLVMTypeMapping {
-    type InV<'c> = TypingSession<'c>;
+impl<'a> TypeMapping for LLVMTypeMapping<'a> {
+    type InV<'c> = TypingSession<'c, 'a>;
 
     type OutV<'c> = BasicTypeEnum<'c>;
 
@@ -48,7 +50,7 @@ impl TypeMapping for LLVMTypeMapping {
     fn map_sum_type<'c>(
         &self,
         sum_type: &HugrSumType,
-        context: TypingSession<'c>,
+        context: TypingSession<'c, 'a>,
         variants: impl IntoIterator<Item = Vec<Self::OutV<'c>>>,
     ) -> Result<Self::SumOutV<'c>> {
         LLVMSumType::try_new2(
@@ -61,7 +63,7 @@ impl TypeMapping for LLVMTypeMapping {
     fn map_function_type<'c>(
         &self,
         _: &HugrFuncType,
-        context: TypingSession<'c>,
+        context: TypingSession<'c, 'a>,
         inputs: impl IntoIterator<Item = Self::OutV<'c>>,
         outputs: impl IntoIterator<Item = Self::OutV<'c>>,
     ) -> Result<Self::FuncOutV<'c>> {

src/emit.rs

@@ -34,16 +34,19 @@ pub use ops::emit_value;
 /// This includes the module itself, a set of extensions for lowering custom
 /// elements, and policy for naming various HUGR elements.
 ///
-/// `'c` names the lifetime of the LLVM context.
-// TODO add another lifetime parameter for `extensions` below.
-pub struct EmitModuleContext<'c, H> {
+/// `'c` names the lifetime of the LLVM context, while `'a` names the lifetime
+/// of other internal references.
+pub struct EmitModuleContext<'c, 'a, H>
+where
+    'a: 'c,
+{
     iw_context: &'c Context,
     module: Module<'c>,
-    extensions: Rc<CodegenExtsMap<'static, H>>,
+    extensions: Rc<CodegenExtsMap<'a, H>>,
     namer: Rc<Namer>,
 }
 
-impl<'c, H> EmitModuleContext<'c, H> {
+impl<'c, 'a, H> EmitModuleContext<'c, 'a, H> {
     delegate! {
         to self.typing_session() {
             /// Convert a [HugrType] into an LLVM [Type](BasicTypeEnum).
@@ -70,7 +73,7 @@ impl<'c, H> EmitModuleContext<'c, H> {
         iw_context: &'c Context,
         module: Module<'c>,
         namer: Rc<Namer>,
-        extensions: Rc<CodegenExtsMap<'static, H>>,
+        extensions: Rc<CodegenExtsMap<'a, H>>,
     ) -> Self {
         Self {
             iw_context,
@@ -88,12 +91,12 @@ impl<'c, H> EmitModuleContext<'c, H> {
     }
 
     /// Returns a reference to the inner [CodegenExtsMap].
-    pub fn extensions(&self) -> Rc<CodegenExtsMap<'static, H>> {
+    pub fn extensions(&self) -> Rc<CodegenExtsMap<'a, H>> {
         self.extensions.clone()
     }
 
     /// Returns a [TypingSession] constructed from it's members.
-    pub fn typing_session(&self) -> TypingSession<'c> {
+    pub fn typing_session(&self) -> TypingSession<'c, 'a> {
         self.extensions
             .type_converter
             .clone()
@@ -235,12 +238,15 @@ impl<'c, H> EmitModuleContext<'c, H> {
 type EmissionSet = HashSet<Node>;
 
 /// Emits [HugrView]s into an LLVM [Module].
-pub struct EmitHugr<'c, H> {
+pub struct EmitHugr<'c, 'a, H>
+where
+    'a: 'c,
+{
     emitted: EmissionSet,
-    module_context: EmitModuleContext<'c, H>,
+    module_context: EmitModuleContext<'c, 'a, H>,
 }
 
-impl<'c, H: HugrView> EmitHugr<'c, H> {
+impl<'c, 'a, H: HugrView> EmitHugr<'c, 'a, H> {
     delegate! {
         to self.module_context {
             /// Returns a reference to the inner [Context].
@@ -257,7 +263,7 @@ impl<'c, H: HugrView> EmitHugr<'c, H> {
         iw_context: &'c Context,
         module: Module<'c>,
         namer: Rc<Namer>,
-        extensions: Rc<CodegenExtsMap<'static, H>>,
+        extensions: Rc<CodegenExtsMap<'a, H>>,
     ) -> Self {
         assert_eq!(iw_context, &module.get_context());
         Self {

src/emit/func.rs

@@ -43,10 +43,11 @@ pub use mailbox::{RowMailBox, RowPromise};
 /// [MailBox](RowMailBox)es are stack allocations that are `alloca`ed in the
 /// first basic block of the function, read from to get the input values of each
 /// node, and written to with the output values of each node.
-///
-// TODO add another lifetime parameter which `emit_context` will need.
-pub struct EmitFuncContext<'c, H> {
-    emit_context: EmitModuleContext<'c, H>,
+pub struct EmitFuncContext<'c, 'a, H>
+where
+    'a: 'c,
+{
+    emit_context: EmitModuleContext<'c, 'a, H>,
     todo: EmissionSet,
     func: FunctionValue<'c>,
     env: HashMap<Wire, ValueMailBox<'c>>,
@@ -55,15 +56,15 @@ pub struct EmitFuncContext<'c, H> {
     launch_bb: BasicBlock<'c>,
 }
 
-impl<'c, H: HugrView> EmitFuncContext<'c, H> {
+impl<'c, 'a, H: HugrView> EmitFuncContext<'c, 'a, H> {
     delegate! {
         to self.emit_context {
             /// Returns the inkwell [Context].
             pub fn iw_context(&self) ->  &'c Context;
             /// Returns the internal [CodegenExtsMap] .
-            pub fn extensions(&self) ->  Rc<CodegenExtsMap<'static,H>>;
+            pub fn extensions(&self) ->  Rc<CodegenExtsMap<'a,H>>;
             /// Returns a new [TypingSession].
-            pub fn typing_session(&self) -> TypingSession<'c>;
+            pub fn typing_session(&self) -> TypingSession<'c, 'a>;
             /// Convert hugr [HugrType] into an LLVM [Type](BasicTypeEnum).
             pub fn llvm_type(&self, hugr_type: &HugrType) -> Result<BasicTypeEnum<'c> >;
             /// Convert a [HugrFuncType] into an LLVM [FunctionType].
@@ -143,9 +144,9 @@ impl<'c, H: HugrView> EmitFuncContext<'c, H> {
     ///
     /// TODO on failure return `emit_context`
     pub fn new(
-        emit_context: EmitModuleContext<'c, H>,
+        emit_context: EmitModuleContext<'c, 'a, H>,
         func: FunctionValue<'c>,
-    ) -> Result<EmitFuncContext<'c, H>> {
+    ) -> Result<EmitFuncContext<'c, 'a, H>> {
         if func.get_first_basic_block().is_some() {
             Err(anyhow!(
                 "EmitContext::new: Function already has a basic block: {:?}",
@@ -180,9 +181,9 @@ impl<'c, H: HugrView> EmitFuncContext<'c, H> {
     /// Create a new anonymous [RowMailBox]. This mailbox is not mapped to any
     /// [Wire]s, and so will not interact with any mailboxes returned from
     /// [EmitFuncContext::node_ins_rmb] or [EmitFuncContext::node_outs_rmb].
-    pub fn new_row_mail_box<'a>(
+    pub fn new_row_mail_box<'t>(
         &mut self,
-        ts: impl IntoIterator<Item = &'a Type>,
+        ts: impl IntoIterator<Item = &'t Type>,
         name: impl AsRef<str>,
     ) -> Result<RowMailBox<'c>> {
         Ok(RowMailBox::new(
@@ -307,7 +308,7 @@ impl<'c, H: HugrView> EmitFuncContext<'c, H> {
 
     /// Consumes the `EmitFuncContext` and returns both the inner
     /// [EmitModuleContext] and the scoped [FuncDefn]s that were encountered.
-    pub fn finish(self) -> Result<(EmitModuleContext<'c, H>, EmissionSet)> {
+    pub fn finish(self) -> Result<(EmitModuleContext<'c, 'a, H>, EmissionSet)> {
         self.builder.position_at_end(self.prologue_bb);
         self.builder.build_unconditional_branch(self.launch_bb)?;
         Ok((self.emit_context, self.todo))