From 02c1541c20adf36ea09825dc7bc745f8487c4bc8 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 12 Nov 2016 18:40:29 +0200
Subject: [PATCH] Move unused aggregate detection to UnusedVariableDetector

It isn't really NodeRemover's job.
---
 source/programcompiler.cpp | 61 +++++++++++++++++++-------------------
 source/programcompiler.h   | 11 +++----
 2 files changed, 34 insertions(+), 38 deletions(-)

diff --git a/source/programcompiler.cpp b/source/programcompiler.cpp
index 55f62ae9..f7d23161 100644
--- a/source/programcompiler.cpp
+++ b/source/programcompiler.cpp
@@ -83,7 +83,7 @@ bool ProgramCompiler::optimize(Stage &stage)
 	remover.to_remove = unused_locator.unused_nodes;
 	remover.apply(stage);
 
-	return remover.n_removed;
+	return !unused_locator.unused_nodes.empty();
 }
 
 void ProgramCompiler::inject_block(Block &target, const Block &source)
@@ -626,6 +626,7 @@ void ProgramCompiler::VariableRenamer::visit(VariableDeclaration &var)
 
 
 ProgramCompiler::UnusedVariableLocator::UnusedVariableLocator():
+	aggregate(0),
 	assignment(false),
 	record_target(false),
 	assignment_target(0),
@@ -656,6 +657,10 @@ void ProgramCompiler::UnusedVariableLocator::visit(VariableReference &var)
 		if(assignment && var.declaration==assignment_target)
 			self_referencing = true;
 	}
+
+	map<VariableDeclaration *, Node *>::iterator i = aggregates.find(var.declaration);
+	if(i!=aggregates.end())
+		unused_nodes.erase(i->second);
 }
 
 void ProgramCompiler::UnusedVariableLocator::visit(MemberAccess &memacc)
@@ -710,50 +715,50 @@ void ProgramCompiler::UnusedVariableLocator::visit(ExpressionStatement &expr)
 	assignment = false;
 }
 
+void ProgramCompiler::UnusedVariableLocator::visit(StructDeclaration &strct)
+{
+	SetForScope<Node *> set(aggregate, &strct);
+	unused_nodes.insert(&strct);
+	TraversingVisitor::visit(strct);
+}
+
 void ProgramCompiler::UnusedVariableLocator::visit(VariableDeclaration &var)
 {
-	unused_nodes.insert(&var);
-	if(var.init_expression)
+	if(aggregate)
+		aggregates[&var] = aggregate;
+	else
 	{
-		unused_nodes.insert(&*var.init_expression);
-		assignments[&var] = &*var.init_expression;
+		unused_nodes.insert(&var);
+		if(var.init_expression)
+		{
+			unused_nodes.insert(&*var.init_expression);
+			assignments[&var] = &*var.init_expression;
+		}
 	}
+	unused_nodes.erase(var.type_declaration);
 	TraversingVisitor::visit(var);
 }
 
+void ProgramCompiler::UnusedVariableLocator::visit(InterfaceBlock &iface)
+{
+	SetForScope<Node *> set(aggregate, &iface);
+	unused_nodes.insert(&iface);
+	TraversingVisitor::visit(iface);
+}
 
-ProgramCompiler::NodeRemover::NodeRemover():
-	n_removed(0),
-	immutable_block(false),
-	remove_block(false)
-{ }
 
 void ProgramCompiler::NodeRemover::visit(Block &block)
 {
-	remove_block = immutable_block;
 	for(list<NodePtr<Node> >::iterator i=block.body.begin(); i!=block.body.end(); )
 	{
-		bool remove = to_remove.count(&**i);
-		if(!remove)
-			remove_block = false;
 		(*i)->visit(*this);
-
-		if(remove ? !immutable_block : remove_block)
-		{
+		if(to_remove.count(&**i))
 			block.body.erase(i++);
-			++n_removed;
-		}
 		else
 			++i;
 	}
 }
 
-void ProgramCompiler::NodeRemover::visit(StructDeclaration &strct)
-{
-	SetFlag set(immutable_block);
-	TraversingVisitor::visit(strct);
-}
-
 void ProgramCompiler::NodeRemover::visit(VariableDeclaration &var)
 {
 	if(to_remove.count(&var))
@@ -767,11 +772,5 @@ void ProgramCompiler::NodeRemover::visit(VariableDeclaration &var)
 		var.init_expression = 0;
 }
 
-void ProgramCompiler::NodeRemover::visit(InterfaceBlock &iface)
-{
-	SetFlag set(immutable_block);
-	TraversingVisitor::visit(iface);
-}
-
 } // namespace GL
 } // namespace Msp
diff --git a/source/programcompiler.h b/source/programcompiler.h
index f1ea1652..829f7535 100644
--- a/source/programcompiler.h
+++ b/source/programcompiler.h
@@ -98,6 +98,8 @@ private:
 	struct UnusedVariableLocator: Visitor
 	{
 		std::set<ProgramSyntax::Node *> unused_nodes;
+		std::map<ProgramSyntax::VariableDeclaration *, ProgramSyntax::Node *> aggregates;
+		ProgramSyntax::Node *aggregate;
 		std::map<ProgramSyntax::VariableDeclaration *, ProgramSyntax::Node *> assignments;
 		bool assignment;
 		bool record_target;
@@ -111,22 +113,17 @@ private:
 		virtual void visit(ProgramSyntax::MemberAccess &);
 		virtual void visit(ProgramSyntax::BinaryExpression &);
 		virtual void visit(ProgramSyntax::ExpressionStatement &);
+		virtual void visit(ProgramSyntax::StructDeclaration &);
 		virtual void visit(ProgramSyntax::VariableDeclaration &);
+		virtual void visit(ProgramSyntax::InterfaceBlock &);
 	};
 
 	struct NodeRemover: Visitor
 	{
 		std::set<ProgramSyntax::Node *> to_remove;
-		unsigned n_removed;
-		bool immutable_block;
-		bool remove_block;
-
-		NodeRemover();
 
 		virtual void visit(ProgramSyntax::Block &);
-		virtual void visit(ProgramSyntax::StructDeclaration &);
 		virtual void visit(ProgramSyntax::VariableDeclaration &);
-		virtual void visit(ProgramSyntax::InterfaceBlock &);
 	};
 
 	ProgramParser parser;
-- 
2.43.0