Function inliner.

4 files changed, 207 insertions, 2 deletions

diff --git a/libjulia/optimiser/FunctionalInliner.cpp b/libjulia/optimiser/FunctionalInliner.cpp
new file mode 100644
index 00000000..0544ee5d
--- /dev/null
+++ b/libjulia/optimiser/FunctionalInliner.cpp
@@ -0,0 +1,71 @@
+/*
+	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/>.
+*/
+/**
+ * Optimiser component that performs function inlining.
+ */
+
+#include <libjulia/optimiser/FunctionalInliner.h>
+
+#include <libjulia/optimiser/InlinableFunctionFilter.h>
+#include <libjulia/optimiser/Substitution.h>
+#include <libjulia/optimiser/Semantics.h>
+
+#include <libsolidity/inlineasm/AsmData.h>
+
+#include <boost/algorithm/cxx11/all_of.hpp>
+
+using namespace std;
+using namespace dev;
+using namespace dev::julia;
+using namespace dev::solidity;
+
+void FunctionalInliner::run()
+{
+	InlinableFunctionFilter filter;
+	filter(m_block);
+	m_inlinableFunctions = filter.inlinableFunctions();
+
+	(*this)(m_block);
+}
+
+
+void FunctionalInliner::visit(Expression& _expression)
+{
+	ASTModifier::visit(_expression);
+	if (_expression.type() == typeid(FunctionCall))
+	{
+		FunctionCall& funCall = boost::get<FunctionCall>(_expression);
+
+		bool movable = boost::algorithm::all_of(
+			funCall.arguments,
+			[=](Expression const& _arg) { return MovableChecker(_arg).movable(); }
+		);
+		if (m_inlinableFunctions.count(funCall.functionName.name) && movable)
+		{
+			FunctionDefinition const& fun = *m_inlinableFunctions.at(funCall.functionName.name);
+			map<string, Expression const*> substitutions;
+			for (size_t i = 0; i < fun.parameters.size(); ++i)
+				substitutions[fun.parameters[i].name] = &funCall.arguments[i];
+			_expression = Substitution(substitutions).translate(*boost::get<Assignment>(fun.body.statements.front()).value);
+
+			// TODO actually in the process of inlining, we could also make a function non-inlinable
+			// because it could now call itself
+
+			// If two functions call each other, we have to exit after some iterations.
+		}
+	}
+}
diff --git a/libjulia/optimiser/FunctionalInliner.h b/libjulia/optimiser/FunctionalInliner.h
new file mode 100644
index 00000000..30c972ff
--- /dev/null
+++ b/libjulia/optimiser/FunctionalInliner.h
@@ -0,0 +1,69 @@
+/*
+	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/>.
+*/
+/**
+ * Optimiser component that performs function inlining.
+ */
+#pragma once
+
+#include <libjulia/optimiser/ASTWalker.h>
+
+#include <libjulia/ASTDataForward.h>
+
+#include <libsolidity/interface/Exceptions.h>
+
+#include <boost/variant.hpp>
+#include <boost/optional.hpp>
+
+#include <set>
+
+namespace dev
+{
+namespace julia
+{
+
+/**
+ * Optimiser component that modifies an AST in place, inlining functions that can be
+ * inlined inside functional expressions, i.e. functions that
+ *  - return a single value
+ *  - have a body like r := <functional expression>
+ *  - neither reference themselves nor r in the right hand side
+ *
+ * Furthermore, the arguments of the function call cannot have any side-effects.
+ *
+ * This component can only be used on sources with unique names.
+ */
+class FunctionalInliner: public ASTModifier
+{
+public:
+	FunctionalInliner(Block& _block):
+		m_block(_block)
+	{}
+
+	void run();
+
+private:
+	virtual void visit(Expression& _expression) override;
+
+	std::map<std::string, FunctionDefinition const*> m_inlinableFunctions;
+	std::map<std::string, std::string> m_varReplacements;
+
+	Block& m_block;
+};
+
+
+}
+}
diff --git a/libjulia/optimiser/InlinableFunctionFilter.cpp b/libjulia/optimiser/InlinableFunctionFilter.cpp
index db9f812d..37e21f0d 100644
--- a/libjulia/optimiser/InlinableFunctionFilter.cpp
+++ b/libjulia/optimiser/InlinableFunctionFilter.cpp
@@ -51,6 +51,8 @@ void InlinableFunctionFilter::operator()(FunctionDefinition const& _function)
 			Assignment const& assignment = boost::get<Assignment>(bodyStatement);
 			if (assignment.variableNames.size() == 1 && assignment.variableNames.front().name == retVariable)
 			{
+				// FIXME: use code size metric here
+
 				// We cannot overwrite previous settings, because this function definition
 				// would not be valid here if we were searching inside a functionally inlinable
 				// function body.
diff --git a/test/libjulia/Inliner.cpp b/test/libjulia/Inliner.cpp
index b583fafc..53776acf 100644
--- a/test/libjulia/Inliner.cpp
+++ b/test/libjulia/Inliner.cpp
@@ -24,6 +24,8 @@
 #include <libjulia/optimiser/InlinableFunctionFilter.h>
 #include <libjulia/optimiser/FunctionalInliner.h>
 
+#include <libsolidity/inlineasm/AsmPrinter.h>
+
 #include <boost/test/unit_test.hpp>
 
 #include <boost/range/adaptors.hpp>
@@ -42,7 +44,7 @@ string inlinableFunctions(string const& _source)
 	auto ast = disambiguate(_source);
 
 	InlinableFunctionFilter filter;
-	filter(*ast);
+	filter(ast);
 
 	return boost::algorithm::join(
 		filter.inlinableFunctions() | boost::adaptors::map_keys,
@@ -50,9 +52,15 @@ string inlinableFunctions(string const& _source)
 	);
 }
 
+string inlineFunctions(string const& _source, bool _julia = true)
+{
+	auto ast = disambiguate(_source, _julia);
+	FunctionalInliner(ast).run();
+	return AsmPrinter(_julia)(ast);
+}
 }
 
-BOOST_AUTO_TEST_SUITE(IuliaInliner)
+BOOST_AUTO_TEST_SUITE(IuliaInlinableFunctionFilter)
 
 BOOST_AUTO_TEST_CASE(smoke_test)
 {
@@ -100,3 +108,58 @@ BOOST_AUTO_TEST_CASE(negative)
 
 
 BOOST_AUTO_TEST_SUITE_END()
+
+BOOST_AUTO_TEST_SUITE(IuliaFunctionInliner)
+
+BOOST_AUTO_TEST_CASE(simple)
+{
+	BOOST_CHECK_EQUAL(
+		inlineFunctions("{ function f() -> x:u256 { x := 2:u256 } let y:u256 := f() }"),
+		format("{ function f() -> x:u256 { x := 2:u256 } let y:u256 := 2:u256 }")
+	);
+}
+
+BOOST_AUTO_TEST_CASE(with_args)
+{
+	BOOST_CHECK_EQUAL(
+		inlineFunctions("{ function f(a:u256) -> x:u256 { x := a } let y:u256 := f(7:u256) }"),
+		format("{ function f(a:u256) -> x:u256 { x := a } let y:u256 := 7:u256 }")
+	);
+}
+
+BOOST_AUTO_TEST_CASE(no_inline_with_mload)
+{
+	// Does not inline because mload could be moved out of sequence
+	BOOST_CHECK_EQUAL(
+		inlineFunctions("{ function f(a) -> x { x := a } let y := f(mload(2)) }", false),
+		format("{ function f(a) -> x { x := a } let y := f(mload(2)) }", false)
+	);
+}
+
+BOOST_AUTO_TEST_CASE(complex_with_evm)
+{
+	BOOST_CHECK_EQUAL(
+		inlineFunctions("{ function f(a) -> x { x := add(a, a) } let y := f(calldatasize()) }", false),
+		format("{ function f(a) -> x { x := add(a, a) } let y := add(calldatasize(), calldatasize()) }", false)
+	);
+}
+
+BOOST_AUTO_TEST_CASE(double_calls)
+{
+	BOOST_CHECK_EQUAL(
+		inlineFunctions(R"({
+			function f(a) -> x { x := add(a, a) }
+			function g(b, c) -> y { y := mul(mload(c), f(b)) }
+			let y := g(calldatasize(), 7)
+		})", false),
+		format(R"({
+			function f(a) -> x { x := add(a, a) }
+			function g(b, c) -> y { y := mul(mload(c), add(b, b)) }
+			let y_1 := mul(mload(7), add(calldatasize(), calldatasize()))
+		})", false)
+	);
+}
+
+// TODO test double recursive calls
+
+BOOST_AUTO_TEST_SUITE_END()