implement immutable variables codegen (#70)

crates/llvm-context/src/polkavm/evm/immutable.rs

@@ -1,14 +1,19 @@
 //! Translates the contract immutable operations.
 
+use inkwell::types::BasicType;
+
 use crate::polkavm::context::address_space::AddressSpace;
 use crate::polkavm::context::code_type::CodeType;
+use crate::polkavm::context::function::runtime;
 use crate::polkavm::context::pointer::Pointer;
 use crate::polkavm::context::Context;
 use crate::polkavm::Dependency;
 
 /// Translates the contract immutable load.
-/// In the deploy code the values are read from the auxiliary heap.
-/// In the runtime code they are requested from the system contract.
+///
+/// In deploy code the values are read from the stack.
+///
+/// In runtime code they are loaded lazily with the `get_immutable_data` syscall.
 pub fn load<'ctx, D>(
     context: &mut Context<'ctx, D>,
     index: inkwell::values::IntValue<'ctx>,
@@ -20,38 +25,27 @@ where
         None => {
             anyhow::bail!("Immutables are not available if the contract part is undefined");
         }
-        Some(CodeType::Deploy) => {
-            let index_double = context.builder().build_int_mul(
-                index,
-                context.word_const(2),
-                "immutable_load_index_double",
-            )?;
-            let offset_absolute = context.builder().build_int_add(
-                index_double,
-                context.word_const(
-                    crate::polkavm::HEAP_AUX_OFFSET_CONSTRUCTOR_RETURN_DATA
-                        + (3 * revive_common::BYTE_LENGTH_WORD) as u64,
-                ),
-                "immutable_offset_absolute",
-            )?;
-            let immutable_pointer = Pointer::new_with_offset(
-                context,
-                AddressSpace::default(),
-                context.word_type(),
-                offset_absolute,
-                "immutable_pointer",
-            );
-            context.build_load(immutable_pointer, "immutable_value")
-        }
+        Some(CodeType::Deploy) => load_from_memory(context, index),
         Some(CodeType::Runtime) => {
-            todo!()
+            context.build_call(
+                context
+                    .get_function(runtime::FUNCTION_LOAD_IMMUTABLE_DATA)
+                    .expect("is always declared for runtime code")
+                    .borrow()
+                    .declaration(),
+                &[],
+                runtime::FUNCTION_LOAD_IMMUTABLE_DATA,
+            );
+            load_from_memory(context, index)
         }
     }
 }
 
 /// Translates the contract immutable store.
-/// In the deploy code the values are written to the auxiliary heap at the predefined offset,
-/// being prepared for returning to the system contract for saving.
+///
+/// In deploy code the values are written to the stack at the predefined offset,
+/// being prepared for storing them using the `set_immutable_data` syscall.
+///
 /// Ignored in the runtime code.
 pub fn store<'ctx, D>(
     context: &mut Context<'ctx, D>,
@@ -66,46 +60,48 @@ where
             anyhow::bail!("Immutables are not available if the contract part is undefined");
         }
         Some(CodeType::Deploy) => {
-            let index_double = context.builder().build_int_mul(
-                index,
-                context.word_const(2),
-                "immutable_load_index_double",
-            )?;
-            let index_offset_absolute = context.builder().build_int_add(
-                index_double,
-                context.word_const(
-                    crate::polkavm::HEAP_AUX_OFFSET_CONSTRUCTOR_RETURN_DATA
-                        + (2 * revive_common::BYTE_LENGTH_WORD) as u64,
+            let immutable_data_pointer = context
+                .get_global(revive_runtime_api::immutable_data::GLOBAL_IMMUTABLE_DATA_POINTER)?
+                .value
+                .as_pointer_value();
+            let immutable_pointer = context.build_gep(
+                Pointer::new(
+                    context.word_type(),
+                    AddressSpace::Stack,
+                    immutable_data_pointer,
                 ),
-                "index_offset_absolute",
-            )?;
-            let index_offset_pointer = Pointer::new_with_offset(
-                context,
-                AddressSpace::default(),
-                context.word_type(),
-                index_offset_absolute,
-                "immutable_index_pointer",
+                &[index],
+                context.word_type().as_basic_type_enum(),
+                "immutable_variable_pointer",
             );
-            context.build_store(index_offset_pointer, index)?;
-
-            let value_offset_absolute = context.builder().build_int_add(
-                index_offset_absolute,
-                context.word_const(revive_common::BYTE_LENGTH_WORD as u64),
-                "value_offset_absolute",
-            )?;
-            let value_offset_pointer = Pointer::new_with_offset(
-                context,
-                AddressSpace::default(),
-                context.word_type(),
-                value_offset_absolute,
-                "immutable_value_pointer",
-            );
-            context.build_store(value_offset_pointer, value)?;
-
-            Ok(())
+            context.build_store(immutable_pointer, value)
         }
         Some(CodeType::Runtime) => {
             anyhow::bail!("Immutable writes are not available in the runtime code");
         }
     }
 }
+
+pub fn load_from_memory<'ctx, D>(
+    context: &mut Context<'ctx, D>,
+    index: inkwell::values::IntValue<'ctx>,
+) -> anyhow::Result<inkwell::values::BasicValueEnum<'ctx>>
+where
+    D: Dependency + Clone,
+{
+    let immutable_data_pointer = context
+        .get_global(revive_runtime_api::immutable_data::GLOBAL_IMMUTABLE_DATA_POINTER)?
+        .value
+        .as_pointer_value();
+    let immutable_pointer = context.build_gep(
+        Pointer::new(
+            context.word_type(),
+            AddressSpace::Stack,
+            immutable_data_pointer,
+        ),
+        &[index],
+        context.word_type().as_basic_type_enum(),
+        "immutable_variable_pointer",
+    );
+    context.build_load(immutable_pointer, "immutable_value")
+}