From e4ad6ef39f25b7d58821ee4e406e7ae3d9d19946 Mon Sep 17 00:00:00 2001
From: chriseth <chris@ethereum.org>
Date: Thu, 24 Mar 2022 01:37:41 +0100
Subject: [PATCH] Use unordered map.

---
 libsolutil/BooleanLP.h |  2 +-
 libsolutil/LP.cpp      |  8 +++++
 libsolutil/LP.h        | 79 ++++++++++++++++++++++++++++++++++++++++--
 3 files changed, 86 insertions(+), 3 deletions(-)

diff --git a/libsolutil/BooleanLP.h b/libsolutil/BooleanLP.h
index f4dab298f..85e7efcde 100644
--- a/libsolutil/BooleanLP.h
+++ b/libsolutil/BooleanLP.h
@@ -123,7 +123,7 @@ private:
 	/// Stack of state, to allow for push()/pop().
 	std::vector<State> m_state{{State{}}};
 
-	std::map<SolvingState, LPResult, SolvingState::Compare> m_lpCache;
+	std::unordered_map<SolvingState, LPResult> m_lpCache;
 
 };
 
diff --git a/libsolutil/LP.cpp b/libsolutil/LP.cpp
index 16e0ed1bd..fa0187a99 100644
--- a/libsolutil/LP.cpp
+++ b/libsolutil/LP.cpp
@@ -504,7 +504,11 @@ bool Constraint::operator<(Constraint const& _other) const
 
 	for (size_t i = 0; i < max(data.size(), _other.data.size()); ++i)
 		if (rational diff = data.get(i) - _other.data.get(i))
+		{
+			//cout << "Exit after " << i << endl;
 			return diff < 0;
+		}
+	//cout << "full traversal of " << max(data.size(), _other.data.size()) << endl;
 
 	return false;
 }
@@ -516,7 +520,11 @@ bool Constraint::operator==(Constraint const& _other) const
 
 	for (size_t i = 0; i < max(data.size(), _other.data.size()); ++i)
 		if (data.get(i) != _other.data.get(i))
+		{
+			//cout << "Exit after " << i << endl;
 			return false;
+		}
+	//cout << "full traversal of " << max(data.size(), _other.data.size()) << endl;
 
 	return true;
 }
diff --git a/libsolutil/LP.h b/libsolutil/LP.h
index 76b74ff50..31a600edb 100644
--- a/libsolutil/LP.h
+++ b/libsolutil/LP.h
@@ -24,6 +24,7 @@
 
 #include <vector>
 #include <variant>
+#include <functional>
 
 namespace solidity::util
 {
@@ -85,9 +86,83 @@ struct SolvingState
 		bool considerVariableNames;
 	};
 
+	bool operator==(SolvingState const& _other) const noexcept {
+		return bounds == _other.bounds && constraints == _other.constraints;
+	}
+
 	std::string toString() const;
 };
 
+}
+
+template <class T>
+inline void hashCombine(std::size_t& _seed, T const& _v)
+{
+	std::hash<T> hasher;
+	_seed ^= hasher(_v) + 0x9e3779b9 + (_seed << 6) + (_seed >> 2);
+}
+
+template <class T>
+inline void hashCombineVector(std::size_t& _seed, std::vector<T> const& _v)
+{
+	hashCombine(_seed, _v.size());
+	for (auto const& x: _v)
+		hashCombine(_seed, x);
+}
+
+template<>
+struct std::hash<solidity::util::SolvingState::Bounds>
+{
+	std::size_t operator()(solidity::util::SolvingState::Bounds const& _bounds) const noexcept
+	{
+		std::size_t result = 0;
+		hashCombine(result, _bounds.lower);
+		hashCombine(result, _bounds.upper);
+		return result;
+	}
+};
+
+template<>
+struct std::hash<solidity::util::LinearExpression>
+{
+	std::size_t operator()(solidity::util::LinearExpression const& _linearExpression) const noexcept
+	{
+		std::size_t result = 0;
+		hashCombine(result, _linearExpression.size());
+		for (auto const& x: _linearExpression.enumerate())
+			hashCombine(result, x.second);
+		return result;
+	}
+};
+
+template<>
+struct std::hash<solidity::util::Constraint>
+{
+	std::size_t operator()(solidity::util::Constraint const& _constraint) const noexcept
+	{
+		std::size_t result = 0;
+		hashCombine(result, _constraint.equality);
+		hashCombine(result, _constraint.data);
+		return result;
+	}
+};
+
+template<>
+struct std::hash<solidity::util::SolvingState>
+{
+	std::size_t operator()(solidity::util::SolvingState const& _solvingState) const noexcept
+	{
+		std::size_t result = 0;
+		hashCombineVector(result, _solvingState.bounds);
+		hashCombineVector(result, _solvingState.constraints);
+		return result;
+	}
+};
+
+
+namespace solidity::util
+{
+
 enum class LPResult
 {
 	Unknown,
@@ -179,7 +254,7 @@ class LPSolver
 {
 public:
 	explicit LPSolver(bool _supportModels = true);
-	explicit LPSolver(std::map<SolvingState, LPResult, SolvingState::Compare>* _cache):
+	explicit LPSolver(std::unordered_map<SolvingState, LPResult>* _cache):
 		m_cache(_cache) {}
 
 
@@ -216,7 +291,7 @@ private:
 	std::vector<size_t> m_subProblemsPerConstraint;
 	/// TODO also store the first infeasible subproblem?
 	/// TODO still retain the cache?
-	std::map<SolvingState, LPResult, SolvingState::Compare>* m_cache = nullptr;
+	std::unordered_map<SolvingState, LPResult>* m_cache = nullptr;
 
 };