From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 9 Oct 2021 16:58:51 +0000 (+0300)
Subject: Also break up arrays which are only indexed by constants
X-Git-Url: http://git.tdb.fi/?p=libs%2Fgl.git;a=commitdiff_plain;h=49e89e55692ecdbccd98b93578d29f89669a9fc0

Also break up arrays which are only indexed by constants
---

diff --git a/source/glsl/optimize.cpp b/source/glsl/optimize.cpp
index 768cfd5d..42e4a86e 100644
--- a/source/glsl/optimize.cpp
+++ b/source/glsl/optimize.cpp
@@ -532,11 +532,19 @@ bool AggregateDismantler::apply(Stage &stage)
 
 		for(const AggregateMember &m: kvp.second.members)
 		{
+			string name;
+			if(m.declaration)
+				name = format("%s_%s", kvp.second.declaration->name, m.declaration->name);
+			else
+				name = format("%s_%d", kvp.second.declaration->name, m.index);
+
 			VariableDeclaration *var = new VariableDeclaration;
 			var->source = kvp.first->source;
 			var->line = kvp.first->line;
-			var->name = get_unused_variable_name(*kvp.second.decl_scope, format("%s_%s", kvp.second.declaration->name, m.declaration->name));
-			var->type = m.declaration->type;
+			var->name = get_unused_variable_name(*kvp.second.decl_scope, name);
+			/* XXX This is kind of brittle and depends on the array declaration's
+			textual type not having brackets in it. */
+			var->type = (m.declaration ? m.declaration : kvp.second.declaration)->type;
 			if(m.initializer)
 				var->init_expression = m.initializer->clone();
 
@@ -570,10 +578,17 @@ void AggregateDismantler::visit(RefPtr<Expression> &expr)
 {
 	r_aggregate_ref = 0;
 	expr->visit(*this);
-	if(r_aggregate_ref && r_reference.chain_len==1 && (r_reference.chain[0]&0x3F)!=0x3F)
+	if(r_aggregate_ref && r_reference.chain_len==1)
 	{
-		r_aggregate_ref->members[r_reference.chain[0]&0x3F].references.push_back(&expr);
-		r_aggregate_ref->members_referenced = true;
+		if((r_reference.chain[0]&0x3F)!=0x3F)
+		{
+			r_aggregate_ref->members[r_reference.chain[0]&0x3F].references.push_back(&expr);
+			r_aggregate_ref->members_referenced = true;
+		}
+		else
+			/* If the accessed member is not known, mark the entire aggregate as
+			referenced. */
+			r_aggregate_ref->referenced = true;
 	}
 	r_aggregate_ref = 0;
 }
@@ -584,6 +599,8 @@ void AggregateDismantler::visit(VariableReference &var)
 		r_reference.declaration = var.declaration;
 	else
 	{
+		/* If an aggregate variable is referenced as a whole, it should not be
+		dismantled. */
 		auto i = aggregates.find(var.declaration);
 		if(i!=aggregates.end())
 			i->second.referenced = true;
@@ -624,7 +641,19 @@ void AggregateDismantler::visit(BinaryExpression &binary)
 			visit(binary.right);
 		}
 
-		add_to_chain(r_reference, Assignment::Target::ARRAY, 0x3F);
+		unsigned index = 0x3F;
+		if(Literal *literal_subscript = dynamic_cast<Literal *>(binary.right.get()))
+			if(literal_subscript->value.check_type<int>())
+				index = literal_subscript->value.value<int>();
+		add_to_chain(r_reference, Assignment::Target::ARRAY, index);
+
+		if(r_reference.declaration && r_reference.chain_len==1)
+		{
+			auto i = aggregates.find(r_reference.declaration);
+			r_aggregate_ref = (i!=aggregates.end() ? &i->second : 0);
+		}
+		else
+			r_aggregate_ref = 0;
 	}
 	else
 	{
@@ -638,6 +667,7 @@ void AggregateDismantler::visit(VariableDeclaration &var)
 	TraversingVisitor::visit(var);
 
 	if(var.interface.empty())
+	{
 		if(const StructDeclaration *strct = dynamic_cast<const StructDeclaration *>(var.type_declaration))
 		{
 			const FunctionCall *init_call = dynamic_cast<const FunctionCall *>(var.init_expression.get());
@@ -656,6 +686,7 @@ void AggregateDismantler::visit(VariableDeclaration &var)
 					{
 						AggregateMember member;
 						member.declaration = mem_decl;
+						member.index = i;
 						if(init_call)
 							member.initializer = init_call->arguments[i];
 						aggre.members.push_back(member);
@@ -664,6 +695,26 @@ void AggregateDismantler::visit(VariableDeclaration &var)
 				}
 			}
 		}
+		else if(const Literal *literal_size = dynamic_cast<const Literal *>(var.array_size.get()))
+		{
+			if(literal_size->value.check_type<int>())
+			{
+				Aggregate &aggre = aggregates[&var];
+				aggre.declaration = &var;
+				aggre.decl_scope = current_block;
+				aggre.insert_point = insert_point;
+
+				int size = literal_size->value.value<int>();
+				for(int i=0; i<size; ++i)
+				{
+					AggregateMember member;
+					member.index = i;
+					// Array initializers are not supported yet
+					aggre.members.push_back(member);
+				}
+			}
+		}
+	}
 }
 
 
diff --git a/source/glsl/optimize.h b/source/glsl/optimize.h
index 1eb0464e..aebe080c 100644
--- a/source/glsl/optimize.h
+++ b/source/glsl/optimize.h
@@ -161,6 +161,7 @@ private:
 	struct AggregateMember
 	{
 		const VariableDeclaration *declaration = 0;
+		unsigned index = 0;
 		RefPtr<Expression> initializer;
 		std::vector<RefPtr<Expression> *> references;
 	};
diff --git a/tests/glsl/unary_operators.glsl b/tests/glsl/unary_operators.glsl
index bd9803b2..baef6451 100644
--- a/tests/glsl/unary_operators.glsl
+++ b/tests/glsl/unary_operators.glsl
@@ -22,7 +22,7 @@ void main()
 	--i;
 	i++;
 	i--;
-	int arr[3];
-	++arr[0];
+	int arr_0;
+	++arr_0;
 }
 */