Yul: Introduces ASTNodeRegistry

[clonker]

This PR supersedes PR #15242. Depends on PR #15821.

It introduces yul::ASTNodeRegistryBuilder and yul::ASTNodeRegistry. Most important bits of the API:

┌──────────────────────────────────────────────────────────────────────────┐                                      
│ASTNodeRegistryBuilder                                                    │                                      
├──────────────────────────────────────────────────────────────────────────┤                                      
│ ASTNodeRegistryBuilder()                                                 │                                      
│ explicit ASTNodeRegistryBuilder(ASTNodeRegistry const& _existingRegistry)│                                      
│                                                                          │                                      
│ ASTNodeRegistry::NodeIdidefine(std::string_view _label)                  │                                      
│ ASTNodeRegistry build() const                                            │                                      
└────────────────────────────────────┬─────────────────────────────────────┘                                      
                                     │                                                                            
                                     │                                                                            
                                     │                                                                            
┌────────────────────────────────────┴─────────────────────────────────────────────────────────────────────────┐  
│ASTNodeRegistry                                                                                               │  
├──────────────────────────────────────────────────────────────────────────────────────────────────────────────┤  
│ ASTNodeRegistry()                                                                                            │  
│ ASTNodeRegistry(std::vector<std::string> const& _labels, std::vector<size_t> const& _nameToLabelMapping)     │  
│                                                                                                              │  
│ std::string_view operator()(NodeIde_id)                                                                      │  
│ std::optional<YulName> findNameForLabel(std::string_view _label) const                                       │  
└────────────────────────────────────┬─────────────────────────────────────────────────────────────────────────┘  
                                     │                                                                            
                                     │                                                                            
                                     │                                                                            
┌────────────────────────────────────┴───────────────────────────────────────────────────────────────────────────┐
│NodeIdDispenser                                                                                                 │
├────────────────────────────────────────────────────────────────────────────────────────────────────────────────┤
│ explicit NodeIdDispenser(ASTNodeRegistry const& _existingRegistry, std::set<std::string> const& _reserved = {})│
│                                                                                                                │
│ NodeId newId(NodeId _parent = 0)                                                                               │
│ NodeId newGhost()                                                                                              │
│ ASTNodeRegistry generate(Block const& _root, Dialect const& _dialect) const;                                   │
└────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘

I have not yet included the NodeIdDispenser, this can be done in a separate PR.

The ASTNodeRegistry lives (immutably) in the AST and can be used to query labels for particular nodes in the AST. But potentially this could store more metadata than just string labels.

A ASTNodeRegistry can be created by using the ASTNodeRegistryBuilder - which would be the preferred way when importing or parsing (see PR #15833):

solidity/libyul/AsmJsonImporter.cpp

Lines 82 to 87 in c2cea37

	NameWithDebugData AsmJsonImporter::createNameWithDebugData(Json const& _node)
	{
	auto nameWithDebugData = createAsmNode<NameWithDebugData>(_node);
	nameWithDebugData.name = m_nodeLabelRegistryBuilder.define(member(_node, "name").get<std::string>());
	return nameWithDebugData;
	}

solidity/libyul/AsmJsonImporter.cpp

Lines 56 to 60 in c2cea37

	AST AsmJsonImporter::createAST(solidity::Json const& _node)
	{
	auto block = createBlock(_node);
	return {m_dialect, m_nodeLabelRegistryBuilder.build(), std::move(block)};
	}

Or, during/after optimization, from the NodeIdDispenser based on the root block, discarding everything that is not part of the current AST, and the dialect to check for collisions with reserved identifiers:

solidity/libyul/optimiser/Suite.cpp

Line 200 in c2cea37

_object.setCode(std::make_shared<AST>(dialect, nameDispenser, std::move(astRoot)));

solidity/libyul/AST.cpp

Lines 110 to 114 in c2cea37

	AST::AST(Dialect const& _dialect, NodeIdDispenser const& _nameDispenser, Block _root):
	m_dialect(_dialect),
	m_labels(_nameDispenser.generateNewLabels(_root, _dialect)),
	m_root(std::move(_root))
	{}

[blishko]

Except the minor comments, it seems OK to me.

[blishko]

@clonker, BTW, one thing that I found confusing was referring to things related to type NodeId as names. Not sure if this is because of YulName, and if this is what you also pointed out as annoying on Monday.
Just saying for the record :)

[clonker]

@clonker, BTW, one thing that I found confusing was referring to things related to type NodeId as names. Not sure if this is because of YulName, and if this is what you also pointed out as annoying on Monday. Just saying for the record :)

You are right and this is what I was referring to on Monday :) I have made things self-consistent now as in everything is "id" and there is no more mention of "name". Change on the larger scope (as in changing YulName to something else) is pending/to be discussed. Thanks for pointing it out!

[blishko]

Looks good to me!
But my review is rather superficial, I don't have enough knowledge about the design and how this is gonna be used.
Someone else should also have a look at this as well :)