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Add initial lowering of a trivial function (#2640)

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This is starting to build out actual lowering logic, for a really simple `fn Main() -> i32 { return 0; }`

Notes for achieving this:

- In semantics, currently function names are bound separate from the signature. When emitting IR, this turns out to be inconvenient because we want to know the name when we process the declaration and the definition. This change addresses that by merging the name into the FunctionDeclaration node, which is also accessible from the definition. It removes the separate BindName. This should be the cause of all the test changes in semantics, because the IR generated changes.

- Add a "Lowering" class which I'm using to hold the llvm builder state. This class now has minimal support for the SemanticsIR generated by the above example.

- In the "Lowering", values from expressions are stored in a DenseMap. I'll keep thinking about whether there's a cleaner way to achieve this, and I'd call it a temporary solution for now. However, this is how the `0` in `return 0` gets properly associated across SemanticsIR instructions, and it'll frequently be an issue in less trivial cases.
This commit is contained in:
Jon Ross-Perkins
2023-02-28 11:30:20 -08:00
committed by GitHub
parent 49726cd89e
commit 32e8fee4ad
46 changed files with 570 additions and 341 deletions
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toolchain/semantics/semantics_parse_tree_handler.cpp
+29 -20
View File
@@ -62,7 +62,7 @@ auto SemanticsParseTreeHandler::Build() -> void {
}
// Pop information for the file-level scope.
node_block_stack_.Pop();
semantics_->top_node_block_id_ = node_block_stack_.Pop();
PopScope();
// Information in all the various context objects should be cleaned up as
@@ -87,16 +87,10 @@ auto SemanticsParseTreeHandler::AddNodeAndPush(ParseTree::Node parse_node,
node_stack_.Push(parse_node, node_id);
}
auto SemanticsParseTreeHandler::BindName(ParseTree::Node name_node,
SemanticsNodeId type_id,
SemanticsNodeId target_id)
-> SemanticsStringId {
CARBON_CHECK(parse_tree_->node_kind(name_node) == ParseNodeKind::DeclaredName)
<< parse_tree_->node_kind(name_node);
auto name_str = parse_tree_->GetNodeText(name_node);
auto name_id = semantics_->AddString(name_str);
AddNode(SemanticsNode::MakeBindName(name_node, type_id, name_id, target_id));
auto SemanticsParseTreeHandler::AddNameToLookup(ParseTree::Node name_node,
SemanticsStringId name_id,
SemanticsNodeId target_id)
-> void {
auto [it, inserted] = current_scope().names.insert(name_id);
if (inserted) {
name_lookup_[name_id].push_back(target_id);
@@ -107,10 +101,23 @@ auto SemanticsParseTreeHandler::BindName(ParseTree::Node name_node,
auto prev_def_id = name_lookup_[name_id].back();
auto prev_def = semantics_->GetNode(prev_def_id);
emitter_->Build(name_node, NameRedefined, name_str)
emitter_->Build(name_node, NameRedefined, semantics_->GetString(name_id))
.Note(prev_def.parse_node(), PreviousDefinition)
.Emit();
}
}
auto SemanticsParseTreeHandler::BindName(ParseTree::Node name_node,
SemanticsNodeId type_id,
SemanticsNodeId target_id)
-> SemanticsStringId {
CARBON_CHECK(parse_tree_->node_kind(name_node) == ParseNodeKind::DeclaredName)
<< parse_tree_->node_kind(name_node);
auto name_str = parse_tree_->GetNodeText(name_node);
auto name_id = semantics_->AddString(name_str);
AddNode(SemanticsNode::MakeBindName(name_node, type_id, name_id, target_id));
AddNameToLookup(name_node, name_id, target_id);
return name_id;
}
@@ -319,7 +326,7 @@ auto SemanticsParseTreeHandler::HandleCallExpression(ParseTree::Node parse_node)
return true;
}
auto callable_id = name_node.GetAsFunctionDeclaration();
auto [_, callable_id] = name_node.GetAsFunctionDeclaration();
auto callable = semantics_->GetCallable(callable_id);
if (!TryTypeConversionOnArgs(call_expr_parse_node, ir_id, refs_id,
@@ -496,14 +503,16 @@ auto SemanticsParseTreeHandler::HandleFunctionDefinitionStart(
auto fn_node =
node_stack_.PopForSoloParseNode(ParseNodeKind::FunctionIntroducer);
auto name_str = parse_tree_->GetNodeText(name_node);
auto name_id = semantics_->AddString(name_str);
auto callable_id =
semantics_->AddCallable({.param_ir_id = param_ir_id,
.param_refs_id = param_refs_id,
.return_type_id = return_type_id});
auto decl_id =
AddNode(SemanticsNode::MakeFunctionDeclaration(fn_node, callable_id));
// TODO: Propagate the type of the function.
BindName(name_node, SemanticsNodeId::Invalid, decl_id);
auto decl_id = AddNode(
SemanticsNode::MakeFunctionDeclaration(fn_node, name_id, callable_id));
AddNameToLookup(name_node, name_id, decl_id);
node_block_stack_.Push();
PushScope();
@@ -657,7 +666,7 @@ auto SemanticsParseTreeHandler::HandleNameReference(ParseTree::Node parse_node)
node_stack_.Push(parse_node, SemanticsNodeId::BuiltinInvalidType);
};
auto name_id = semantics_->GetString(name_str);
auto name_id = semantics_->GetStringID(name_str);
if (!name_id) {
name_not_found();
return true;
@@ -784,7 +793,7 @@ auto SemanticsParseTreeHandler::HandleReturnStatement(
CARBON_CHECK(!return_scope_stack_.empty());
const auto& fn_node = semantics_->GetNode(return_scope_stack_.back());
const auto callable =
semantics_->GetCallable(fn_node.GetAsFunctionDeclaration());
semantics_->GetCallable(fn_node.GetAsFunctionDeclaration().second);
if (parse_tree_->node_kind(node_stack_.PeekParseNode()) ==
ParseNodeKind::ReturnStatementStart) {
@@ -937,7 +946,7 @@ auto SemanticsParseTreeHandler::HandleVariableDeclaration(
auto binding = node_stack_.PopForParseNodeAndNameId();
// Restore the name now that the initializer is complete.
AddNameToLookup(binding.second, storage_id);
ReaddNameToLookup(binding.second, storage_id);
auto storage_type =
TryTypeConversion(parse_node, storage_id, last_child.second,