From ec0b78595d6c8fc08f65947f1b082cbe4504f1e9 Mon Sep 17 00:00:00 2001
From: chriseth <chris@ethereum.org>
Date: Wed, 17 Apr 2019 19:14:27 +0200
Subject: [PATCH] [Yul] Wasm dialect.

---
 libyul/CMakeLists.txt                |  2 +
 libyul/backends/wasm/WasmDialect.cpp | 75 ++++++++++++++++++++++++++++
 libyul/backends/wasm/WasmDialect.h   | 55 ++++++++++++++++++++
 3 files changed, 132 insertions(+)
 create mode 100644 libyul/backends/wasm/WasmDialect.cpp
 create mode 100644 libyul/backends/wasm/WasmDialect.h

diff --git a/libyul/CMakeLists.txt b/libyul/CMakeLists.txt
index ab0f53c97..b70d813b4 100644
--- a/libyul/CMakeLists.txt
+++ b/libyul/CMakeLists.txt
@@ -38,6 +38,8 @@ add_library(yul
 	backends/evm/EVMObjectCompiler.h
 	backends/evm/NoOutputAssembly.h
 	backends/evm/NoOutputAssembly.cpp
+	backends/wasm/WasmDialect.cpp
+	backends/wasm/WasmDialect.h
 	optimiser/ASTCopier.cpp
 	optimiser/ASTCopier.h
 	optimiser/ASTWalker.cpp
diff --git a/libyul/backends/wasm/WasmDialect.cpp b/libyul/backends/wasm/WasmDialect.cpp
new file mode 100644
index 000000000..5e03b037f
--- /dev/null
+++ b/libyul/backends/wasm/WasmDialect.cpp
@@ -0,0 +1,75 @@
+/*
+	This file is part of solidity.
+
+	solidity is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/**
+ * Dialects for Wasm.
+ */
+
+#include <libyul/backends/wasm/WasmDialect.h>
+
+using namespace std;
+using namespace yul;
+
+WasmDialect::WasmDialect(AsmFlavour _flavour):
+	Dialect{_flavour}
+{
+	for (auto const& name: {
+		"i64.add",
+		"i64.sub",
+		"i64.mul",
+		"i64.div_u",
+		"i64.rem_u",
+		"i64.and",
+		"i64.or",
+		"i64.xor",
+		"i64.shl",
+		"i64.shr_u",
+		"i64.eq",
+		"i64.ne",
+		"i64.lt_u",
+		"i64.gt_u",
+		"i64.le_u",
+		"i64.ge_u"
+	})
+		addFunction(name, 2, 1);
+
+	addFunction("i64.eqz", 1, 1);
+	addFunction("i64.store", 2, 0);
+	addFunction("i64.load", 1, 1);
+
+	addFunction("drop", 1, 0);
+	addFunction("unreachable", 0, 0);
+}
+
+BuiltinFunction const* WasmDialect::builtin(YulString _name) const
+{
+	auto it = m_functions.find(_name);
+	if (it != m_functions.end())
+		return &it->second;
+	else
+		return nullptr;
+}
+
+void WasmDialect::addFunction(string _name, size_t _params, size_t _returns)
+{
+	YulString name{std::move(_name)};
+	BuiltinFunction& f = m_functions[name];
+	f.name = name;
+	f.parameters.resize(_params);
+	f.returns.resize(_returns);
+	f.movable = false;
+	f.literalArguments = false;
+}
diff --git a/libyul/backends/wasm/WasmDialect.h b/libyul/backends/wasm/WasmDialect.h
new file mode 100644
index 000000000..71509ca08
--- /dev/null
+++ b/libyul/backends/wasm/WasmDialect.h
@@ -0,0 +1,55 @@
+/*
+	This file is part of solidity.
+
+	solidity is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/**
+ * Dialects for Wasm.
+ */
+
+#pragma once
+
+#include <libyul/Dialect.h>
+
+#include <map>
+
+namespace yul
+{
+
+class YulString;
+using Type = YulString;
+struct FunctionCall;
+struct Object;
+
+/**
+ * Yul dialect for Wasm as a backend.
+ *
+ * Builtin functions are a subset of the wasm instructions, always implicitly assuming
+ * unsigned 64 bit types.
+ *
+ * !This is subject to changes!
+ */
+struct WasmDialect: public Dialect
+{
+	WasmDialect(AsmFlavour _flavour);
+
+	BuiltinFunction const* builtin(YulString _name) const override;
+
+protected:
+	void addFunction(std::string _name, size_t _params, size_t _returns);
+
+	std::map<YulString, BuiltinFunction> m_functions;
+};
+
+}