resolc crate (#328)

- Factor the YUL crate out of `revive-solidity`.
- `revive-solidity` is in reality not a Solidity implementation but the
revive solidity compiler driver (`resolc`). By renaming we not only get
this straight but also a binary with the same name as the crate which
should be less confusing.

---------

Signed-off-by: Cyrill Leutwiler <bigcyrill@hotmail.com>

crates/resolc/src/project/contract/ir/mod.rs

@@ -0,0 +1,66 @@
+//! The contract source code.
+
+pub mod llvm_ir;
+pub mod yul;
+
+use std::collections::HashSet;
+
+use serde::Deserialize;
+use serde::Serialize;
+
+use revive_yul::parser::statement::object::Object;
+
+use self::llvm_ir::LLVMIR;
+use self::yul::Yul;
+
+/// The contract source code.
+#[derive(Debug, Serialize, Deserialize, Clone)]
+#[allow(clippy::upper_case_acronyms)]
+pub enum IR {
+    /// The Yul source code.
+    Yul(Yul),
+    /// The LLVM IR source code.
+    LLVMIR(LLVMIR),
+}
+
+impl IR {
+    /// A shortcut constructor.
+    pub fn new_yul(source_code: String, object: Object) -> Self {
+        Self::Yul(Yul::new(source_code, object))
+    }
+
+    /// A shortcut constructor.
+    pub fn new_llvm_ir(path: String, source: String) -> Self {
+        Self::LLVMIR(LLVMIR::new(path, source))
+    }
+
+    /// Get the list of missing deployable libraries.
+    pub fn get_missing_libraries(&self) -> HashSet<String> {
+        match self {
+            Self::Yul(inner) => inner.get_missing_libraries(),
+            Self::LLVMIR(_inner) => HashSet::new(),
+        }
+    }
+}
+
+impl<D> revive_llvm_context::PolkaVMWriteLLVM<D> for IR
+where
+    D: revive_llvm_context::PolkaVMDependency + Clone,
+{
+    fn declare(
+        &mut self,
+        context: &mut revive_llvm_context::PolkaVMContext<D>,
+    ) -> anyhow::Result<()> {
+        match self {
+            Self::Yul(inner) => inner.declare(context),
+            Self::LLVMIR(_inner) => Ok(()),
+        }
+    }
+
+    fn into_llvm(self, context: &mut revive_llvm_context::PolkaVMContext<D>) -> anyhow::Result<()> {
+        match self {
+            Self::Yul(inner) => inner.into_llvm(context),
+            Self::LLVMIR(_inner) => Ok(()),
+        }
+    }
+}