CompilerStack: Yul AST generation only on demand

- The JSON artifacts take a lot of memory so always generating them is very wasteful.
- Even when requested, they are only relevant while the current contract is being copmiled. We only really want to store the serialized JSON that will be returned to the user.
- This actually also speeds up compilation quite a bit.

Changelog.md

@@ -5,6 +5,7 @@ Language Features:
 
 Compiler Features:
  * Code Generator: Transient storage value type state variables are now supported by the legacy pipeline.
+ * CompilerStack: Generate Yul ASTs only on demand to reduce memory usage.
 
 
 Bugfixes:

libsolidity/interface/CompilerStack.cpp

@@ -956,21 +956,24 @@ std::string const& CompilerStack::yulIR(std::string const& _contractName) const
 	return contract(_contractName).yulIR;
 }
 
-Json const& CompilerStack::yulIRAst(std::string const& _contractName) const
+Json CompilerStack::yulIRAst(std::string const& _contractName) const
 {
 	solAssert(m_stackState == CompilationSuccessful, "Compilation was not successful.");
 	solUnimplementedAssert(!isExperimentalSolidity());
-	return contract(_contractName).yulIRAst;
+
+	// NOTE: Intentionally not using LazyInit. The artifact can get very large and we don't want to
+	// keep it around when compiling a large project containing many contracts.
+	return loadGeneratedIR(contract(_contractName).yulIR).astJson();
 }
 
-Json const& CompilerStack::yulCFGJson(std::string const& _contractName) const
+Json CompilerStack::yulCFGJson(std::string const& _contractName) const
 {
-	if (m_stackState != CompilationSuccessful)
-		solThrow(CompilerError, "Compilation was not successful.");
-
+	solAssert(m_stackState == CompilationSuccessful, "Compilation was not successful.");
 	solUnimplementedAssert(!isExperimentalSolidity());
 
-	return contract(_contractName).yulCFGJson;
+	// NOTE: Intentionally not using LazyInit. The artifact can get very large and we don't want to
+	// keep it around when compiling a large project containing many contracts.
+	return loadGeneratedIR(contract(_contractName).yulIR).cfgJson();
 }
 
 std::string const& CompilerStack::yulIROptimized(std::string const& _contractName) const
@@ -979,11 +982,14 @@ std::string const& CompilerStack::yulIROptimized(std::string const& _contractNam
 	return contract(_contractName).yulIROptimized;
 }
 
-Json const& CompilerStack::yulIROptimizedAst(std::string const& _contractName) const
+Json CompilerStack::yulIROptimizedAst(std::string const& _contractName) const
 {
 	solAssert(m_stackState == CompilationSuccessful, "Compilation was not successful.");
 	solUnimplementedAssert(!isExperimentalSolidity());
-	return contract(_contractName).yulIROptimizedAst;
+
+	// NOTE: Intentionally not using LazyInit. The artifact can get very large and we don't want to
+	// keep it around when compiling a large project containing many contracts.
+	return loadGeneratedIR(contract(_contractName).yulIROptimized).astJson();
 }
 
 evmasm::LinkerObject const& CompilerStack::object(std::string const& _contractName) const
@@ -1539,13 +1545,10 @@ void CompilerStack::generateIR(ContractDefinition const& _contract, bool _unopti
 	}
 
 	YulStack stack = loadGeneratedIR(compiledContract.yulIR);
-	compiledContract.yulIRAst = stack.astJson();
-	compiledContract.yulCFGJson = stack.cfgJson();
 	if (!_unoptimizedOnly)
 	{
 		stack.optimize();
 		compiledContract.yulIROptimized = stack.print();
-		compiledContract.yulIROptimizedAst = stack.astJson();
 	}
 }
 

libsolidity/interface/CompilerStack.h

@@ -295,15 +295,15 @@ class CompilerStack: public langutil::CharStreamProvider, public evmasm::Abstrac
 	std::string const& yulIR(std::string const& _contractName) const;
 
 	/// @returns the IR representation of a contract AST in format.
-	Json const& yulIRAst(std::string const& _contractName) const;
+	Json yulIRAst(std::string const& _contractName) const;
 
 	/// @returns the optimized IR representation of a contract.
 	std::string const& yulIROptimized(std::string const& _contractName) const;
 
 	/// @returns the optimized IR representation of a contract AST in JSON format.
-	Json const& yulIROptimizedAst(std::string const& _contractName) const;
+	Json yulIROptimizedAst(std::string const& _contractName) const;
 
-	Json const& yulCFGJson(std::string const& _contractName) const;
+	Json yulCFGJson(std::string const& _contractName) const;
 
 	/// @returns the assembled object for a contract.
 	virtual evmasm::LinkerObject const& object(std::string const& _contractName) const override;
@@ -416,9 +416,6 @@ class CompilerStack: public langutil::CharStreamProvider, public evmasm::Abstrac
 		evmasm::LinkerObject runtimeObject; ///< Runtime object.
 		std::string yulIR; ///< Yul IR code straight from the code generator.
 		std::string yulIROptimized; ///< Reparsed and possibly optimized Yul IR code.
-		Json yulIRAst; ///< JSON AST of Yul IR code.
-		Json yulIROptimizedAst; ///< JSON AST of optimized Yul IR code.
-		Json yulCFGJson; ///< JSON CFG of Yul IR code.
 		util::LazyInit<std::string const> metadata; ///< The metadata json that will be hashed into the chain.
 		util::LazyInit<Json const> abi;
 		util::LazyInit<Json const> storageLayout;