From f5188158f7edbc672cfc2b5b9125730bbf1886b1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kamil=20=C5=9Aliwak?= <kamil.sliwak@codepoets.it>
Date: Tue, 9 Jan 2024 16:44:27 +0100
Subject: [PATCH] Remove obsolete gas cost tiers

- They're no longer used because the cost depends on the EVM version.
---
 libevmasm/Assembly.cpp        |  1 -
 libevmasm/GasMeter.cpp        | 24 +++++++++++++-----------
 libevmasm/Instruction.cpp     | 12 ++++++------
 libevmasm/Instruction.h       |  2 --
 solc/CommandLineInterface.cpp |  2 --
 5 files changed, 19 insertions(+), 22 deletions(-)

diff --git a/libevmasm/Assembly.cpp b/libevmasm/Assembly.cpp
index ab6ac2c63..3f067ff6b 100644
--- a/libevmasm/Assembly.cpp
+++ b/libevmasm/Assembly.cpp
@@ -29,7 +29,6 @@
 #include <libevmasm/JumpdestRemover.h>
 #include <libevmasm/BlockDeduplicator.h>
 #include <libevmasm/ConstantOptimiser.h>
-#include <libevmasm/GasMeter.h>
 
 #include <liblangutil/CharStream.h>
 #include <liblangutil/Exceptions.h>
diff --git a/libevmasm/GasMeter.cpp b/libevmasm/GasMeter.cpp
index 5982b8a08..e237e32a2 100644
--- a/libevmasm/GasMeter.cpp
+++ b/libevmasm/GasMeter.cpp
@@ -274,18 +274,20 @@ unsigned GasMeter::runGas(Instruction _instruction, langutil::EVMVersion _evmVer
 
 	switch (instructionInfo(_instruction, _evmVersion).gasPriceTier)
 	{
-	case Tier::Zero:		return GasCosts::tier0Gas;
-	case Tier::Base:		return GasCosts::tier1Gas;
-	case Tier::VeryLow:		return GasCosts::tier2Gas;
-	case Tier::Low:			return GasCosts::tier3Gas;
-	case Tier::Mid:			return GasCosts::tier4Gas;
-	case Tier::High:		return GasCosts::tier5Gas;
-	case Tier::Ext:			return GasCosts::tier6Gas;
-	case Tier::WarmAccess:	return GasCosts::warmStorageReadCost;
-	default: break;
+	case Tier::Zero:        return GasCosts::tier0Gas;
+	case Tier::Base:        return GasCosts::tier1Gas;
+	case Tier::VeryLow:     return GasCosts::tier2Gas;
+	case Tier::Low:         return GasCosts::tier3Gas;
+	case Tier::Mid:         return GasCosts::tier4Gas;
+	case Tier::High:        return GasCosts::tier5Gas;
+	case Tier::Ext:         return GasCosts::tier6Gas;
+	case Tier::WarmAccess:  return GasCosts::warmStorageReadCost;
+
+	case Tier::Special:
+	case Tier::Invalid:
+		assertThrow(false, OptimizerException, "Invalid gas tier for instruction " + instructionInfo(_instruction, _evmVersion).name);
 	}
-	assertThrow(false, OptimizerException, "Invalid gas tier for instruction " + instructionInfo(_instruction, _evmVersion).name);
-	return 0;
+	util::unreachable();
 }
 
 u256 GasMeter::dataGas(bytes const& _data, bool _inCreation, langutil::EVMVersion _evmVersion)
diff --git a/libevmasm/Instruction.cpp b/libevmasm/Instruction.cpp
index a21f33e18..4e0684b6b 100644
--- a/libevmasm/Instruction.cpp
+++ b/libevmasm/Instruction.cpp
@@ -211,7 +211,7 @@ static std::map<Instruction, InstructionInfo> const c_instructionInfo =
 	{ Instruction::SIGNEXTEND,	{ "SIGNEXTEND",		0, 2, 1, false, Tier::Low } },
 	{ Instruction::KECCAK256,	{ "KECCAK256",			0, 2, 1, true, Tier::Special } },
 	{ Instruction::ADDRESS,		{ "ADDRESS",		0, 0, 1, false, Tier::Base } },
-	{ Instruction::BALANCE,		{ "BALANCE",		0, 1, 1, false, Tier::Balance } },
+	{ Instruction::BALANCE,     { "BALANCE",        0, 1, 1, false, Tier::Special } },
 	{ Instruction::ORIGIN,		{ "ORIGIN",			0, 0, 1, false, Tier::Base } },
 	{ Instruction::CALLER,		{ "CALLER",			0, 0, 1, false, Tier::Base } },
 	{ Instruction::CALLVALUE,	{ "CALLVALUE",		0, 0, 1, false, Tier::Base } },
@@ -221,12 +221,12 @@ static std::map<Instruction, InstructionInfo> const c_instructionInfo =
 	{ Instruction::CODESIZE,	{ "CODESIZE",		0, 0, 1, false, Tier::Base } },
 	{ Instruction::CODECOPY,	{ "CODECOPY",		0, 3, 0, true, Tier::VeryLow } },
 	{ Instruction::GASPRICE,	{ "GASPRICE",		0, 0, 1, false, Tier::Base } },
-	{ Instruction::EXTCODESIZE,	{ "EXTCODESIZE",	0, 1, 1, false, Tier::ExtCode } },
-	{ Instruction::EXTCODECOPY,	{ "EXTCODECOPY",	0, 4, 0, true, Tier::ExtCode } },
-	{ Instruction::RETURNDATASIZE,	{"RETURNDATASIZE",	0, 0, 1, false, Tier::Base } },
-	{ Instruction::RETURNDATACOPY,	{"RETURNDATACOPY",	0, 3, 0, true, Tier::VeryLow } },
+	{ Instruction::EXTCODESIZE, { "EXTCODESIZE",    0, 1, 1, false, Tier::Special } },
+	{ Instruction::EXTCODECOPY, { "EXTCODECOPY",    0, 4, 0, true, Tier::Special } },
+	{ Instruction::RETURNDATASIZE, {"RETURNDATASIZE", 0, 0, 1, false, Tier::Base } },
+	{ Instruction::RETURNDATACOPY, {"RETURNDATACOPY", 0, 3, 0, true, Tier::VeryLow } },
 	{ Instruction::MCOPY,       { "MCOPY",          0, 3, 0, true, Tier::VeryLow } },
-	{ Instruction::EXTCODEHASH,	{ "EXTCODEHASH",	0, 1, 1, false, Tier::Balance } },
+	{ Instruction::EXTCODEHASH, { "EXTCODEHASH",    0, 1, 1, false, Tier::Special } },
 	{ Instruction::BLOCKHASH,	{ "BLOCKHASH",		0, 1, 1, false, Tier::Ext } },
 	{ Instruction::BLOBHASH,    { "BLOBHASH",       0, 1, 1, false, Tier::VeryLow } },
 	{ Instruction::COINBASE,	{ "COINBASE",		0, 0, 1, false, Tier::Base } },
diff --git a/libevmasm/Instruction.h b/libevmasm/Instruction.h
index 1733863aa..d29a6feca 100644
--- a/libevmasm/Instruction.h
+++ b/libevmasm/Instruction.h
@@ -297,8 +297,6 @@ enum class Tier
 	High,		// 10, Slow
 	Ext,		// 20, Ext
 	WarmAccess,	// 100, Warm Access
-	ExtCode,	// 700, Extcode
-	Balance,	// 400, Balance
 	Special,	// multiparam or otherwise special
 	Invalid		// Invalid.
 };
diff --git a/solc/CommandLineInterface.cpp b/solc/CommandLineInterface.cpp
index 7181bfd4c..4c08efb51 100644
--- a/solc/CommandLineInterface.cpp
+++ b/solc/CommandLineInterface.cpp
@@ -43,9 +43,7 @@
 
 #include <libyul/YulStack.h>
 
-#include <libevmasm/Instruction.h>
 #include <libevmasm/Disassemble.h>
-#include <libevmasm/GasMeter.h>
 
 #include <liblangutil/Exceptions.h>
 #include <liblangutil/SourceReferenceFormatter.h>