llvm-context: modularize compiler builtin functions (#234)

- Add the revive runtime function interface to minimize boiler plate code. - Outline heavily repeated code into dedicated functions to bring down code size. - The code size tests builds optimized for size. - Function attributes are passed as slices. This significantly brings down the code size for all OpenZeppelin wizard contracts (using all possible features) compiled against OpenZeppelin `v5.0.0` with size optimizations. |contract|| `-Oz` main | `-Oz` PR || `-O3` main | `-O3` PR | |-|-|-|-|-|-|-| |erc1155.sol||100K|67K||114K|147K| |erc20.sol||120K|90K||160K|191K| |erc721.sol||128K|101K||178K|214K| |governor.sol||226K|165K||293K|349K| |rwa.sol||116K|85K||154K|185K| |stable.sol||116K|86K||155K|192K| On the flip side this introduces a heavy penalty for cycle optimized builds. Setting the no-inline attributes for cycle optimized builds helps a lot but heavily penalizes runtime speed (LLVM does not yet inline everything properly - to be investigated later on). Next steps: - Modularize more functions - Refactor the YUL function arguments to use pointers instead of values - Afterwards check if LLVM still has trouble inline-ing properly on O3 or set the no-inline attribute if it does not penalize runtime performance too bad.
2026-06-17 11:11:10 +00:00 · 2025-02-25 16:47:01 +01:00
parent 7ffe64ed7c
commit a07968205b
32 changed files with 1444 additions and 655 deletions
@@ -0,0 +1,113 @@
+//! The revive compiler runtime function interface definition.
+//!
+//! Common routines should not be inlined but extracted into smaller functions.
+//! This benefits contract code size.
+
+use crate::optimizer::settings::size_level::SizeLevel;
+use crate::polkavm::context::function::declaration::Declaration;
+use crate::polkavm::context::function::Function;
+use crate::polkavm::context::Attribute;
+use crate::polkavm::context::Context;
+use crate::polkavm::Dependency;
+
+/// The revive runtime function interface simplifies declaring runtime functions
+/// and code emitting by providing helpful default implementations.
+pub trait RuntimeFunction<D>
+where
+    D: Dependency + Clone,
+{
+    /// The function name.
+    const NAME: &'static str;
+
+    const ATTRIBUTES: &'static [Attribute] = &[
+        Attribute::NoFree,
+        Attribute::NoRecurse,
+        Attribute::WillReturn,
+    ];
+
+    /// The function type.
+    fn r#type<'ctx>(context: &Context<'ctx, D>) -> inkwell::types::FunctionType<'ctx>;
+
+    /// Declare the function.
+    fn declare(&self, context: &mut Context<D>) -> anyhow::Result<()> {
+        let function = context.add_function(
+            Self::NAME,
+            Self::r#type(context),
+            0,
+            Some(inkwell::module::Linkage::External),
+        )?;
+
+        let mut attributes = Self::ATTRIBUTES.to_vec();
+        attributes.extend_from_slice(match context.optimizer_settings().level_middle_end_size {
+            SizeLevel::Zero => &[],
+            _ => &[Attribute::OptimizeForSize, Attribute::MinSize],
+        });
+        Function::set_attributes(
+            context.llvm(),
+            function.borrow().declaration(),
+            &attributes,
+            true,
+        );
+
+        Ok(())
+    }
+
+    /// Get the function declaration.
+    fn declaration<'ctx>(context: &Context<'ctx, D>) -> Declaration<'ctx> {
+        context
+            .get_function(Self::NAME)
+            .unwrap_or_else(|| panic!("runtime function {} should be declared", Self::NAME))
+            .borrow()
+            .declaration()
+    }
+
+    /// Emit the function.
+    fn emit(&self, context: &mut Context<D>) -> anyhow::Result<()> {
+        context.set_current_function(Self::NAME, None)?;
+        context.set_basic_block(context.current_function().borrow().entry_block());
+
+        let return_value = self.emit_body(context)?;
+        self.emit_epilogue(context, return_value);
+
+        context.pop_debug_scope();
+
+        Ok(())
+    }
+
+    /// Emit the function body.
+    fn emit_body<'ctx>(
+        &self,
+        context: &mut Context<'ctx, D>,
+    ) -> anyhow::Result<Option<inkwell::values::BasicValueEnum<'ctx>>>;
+
+    /// Emit the function return instructions.
+    fn emit_epilogue<'ctx>(
+        &self,
+        context: &mut Context<'ctx, D>,
+        return_value: Option<inkwell::values::BasicValueEnum<'ctx>>,
+    ) {
+        let return_block = context.current_function().borrow().return_block();
+        context.build_unconditional_branch(return_block);
+        context.set_basic_block(return_block);
+        match return_value {
+            Some(value) => context.build_return(Some(&value)),
+            None => context.build_return(None),
+        }
+    }
+
+    /// Get the nth function paramater.
+    fn paramater<'ctx>(
+        context: &Context<'ctx, D>,
+        index: usize,
+    ) -> inkwell::values::BasicValueEnum<'ctx> {
+        let name = Self::NAME;
+        context
+            .get_function(name)
+            .unwrap_or_else(|| panic!("runtime function {name} should be declared"))
+            .borrow()
+            .declaration()
+            .function_value()
+            .get_nth_param(index as u32)
+            .unwrap_or_else(|| panic!("runtime function {name} should have parameter #{index}"))
+    }
+}