Emerge Yul recompiler (#1)

Provide a modified (and incomplete) version of ZKSync zksolc that can compile the most basic contracts

crates/pallet-contracts-pvm-llapi/src/lib.rs

@@ -0,0 +1,42 @@
+//! This crate vendors the [PolkaVM][0] C API and provides a LLVM module for interacting
+//! with the `pallet-contracts` runtime API.
+//!
+//! At present, the contracts pallet requires blobs to export `call` and `deploy`,
+//! and offers a bunch of [runtime API methods][1]. The provided [module] implements
+//! those exports and imports.
+//!
+//! [0]: [https://crates.io/crates/polkavm]
+//! [1]: [https://docs.rs/pallet-contracts/26.0.0/pallet_contracts/api_doc/index.html]
+//!
+
+use inkwell::{context::Context, memory_buffer::MemoryBuffer, module::Module, support::LLVMString};
+
+include!(concat!(env!("OUT_DIR"), "/polkavm_guest.rs"));
+
+/// Creates a LLVM module from the [BITCODE].
+///
+/// The module does:
+/// - Export the `call` and `deploy` functions (which are named thereafter).
+/// - Import (most) `pallet-contracts` runtime API functions.
+///
+/// Returns `Error` if the bitcode fails to parse, which should never happen.
+pub fn module<'context>(
+    context: &'context Context,
+    module_name: &str,
+) -> Result<Module<'context>, LLVMString> {
+    let buf = MemoryBuffer::create_from_memory_range(BITCODE, module_name);
+    Module::parse_bitcode_from_buffer(&buf, context)
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn it_works() {
+        inkwell::targets::Target::initialize_riscv(&Default::default());
+        let context = inkwell::context::Context::create();
+        let module = crate::module(&context, "polkavm_guest").unwrap();
+
+        assert!(module.get_function("call").is_some());
+        assert!(module.get_function("deploy").is_some());
+    }
+}