From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 10 Dec 2016 20:43:51 +0000 (+0200)
Subject: Some fixes to assignment management in UnusedVariableLocator
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=4fe225bf15048fcb7a678370f87d09f2de37031a;p=libs%2Fgl.git

Some fixes to assignment management in UnusedVariableLocator

Sometimes assignments were being removed when they shouldn't (reference
from a conditional sub-block).  Other times they weren't being removed
when they should (followup assignment in the same block).
---

diff --git a/source/programcompiler.cpp b/source/programcompiler.cpp
index 14c9d3d3..cc4b5efe 100644
--- a/source/programcompiler.cpp
+++ b/source/programcompiler.cpp
@@ -1229,8 +1229,7 @@ void ProgramCompiler::UnusedVariableLocator::apply(Stage &s)
 		if(!i->second.referenced)
 		{
 			unused_nodes.insert(i->first);
-			for(vector<Node *>::iterator j=i->second.assignments.begin(); j!=i->second.assignments.end(); ++j)
-				unused_nodes.insert(*j);
+			clear_assignments(i->second, true);
 		}
 	}
 	variables.pop_back();
@@ -1282,11 +1281,21 @@ void ProgramCompiler::UnusedVariableLocator::record_assignment(VariableDeclarati
 {
 	VariableInfo &var_info = variables.back()[&var];
 	if(!self_ref)
-		var_info.assignments.clear();
+		clear_assignments(var_info, true);
 	var_info.assignments.push_back(&node);
 	var_info.conditionally_assigned = false;
 }
 
+void ProgramCompiler::UnusedVariableLocator::clear_assignments(VariableInfo &var_info, bool mark_unused)
+{
+	if(mark_unused)
+	{
+		for(vector<Node *>::iterator i=var_info.assignments.begin(); i!=var_info.assignments.end(); ++i)
+			unused_nodes.insert(*i);
+	}
+	var_info.assignments.clear();
+}
+
 void ProgramCompiler::UnusedVariableLocator::visit(ExpressionStatement &expr)
 {
 	assignment = 0;
@@ -1350,8 +1359,7 @@ void ProgramCompiler::UnusedVariableLocator::merge_down_variables()
 		{
 			if(!i->second.referenced)
 				unused_nodes.insert(i->first);
-			for(vector<Node *>::iterator j=i->second.assignments.begin(); j!=i->second.assignments.end(); ++j)
-				unused_nodes.insert(*j);
+			clear_assignments(i->second, true);
 			continue;
 		}
 
@@ -1360,11 +1368,9 @@ void ProgramCompiler::UnusedVariableLocator::merge_down_variables()
 			parent_variables.insert(*i);
 		else
 		{
-			if(!i->second.conditionally_assigned)
-			{
-				j->second.assignments.clear();
-				j->second.conditionally_assigned = true;
-			}
+			if(i->second.referenced || !i->second.conditionally_assigned)
+				clear_assignments(j->second, !i->second.referenced);
+			j->second.conditionally_assigned = i->second.conditionally_assigned;
 			j->second.referenced |= i->second.referenced;
 			j->second.assignments.insert(j->second.assignments.end(), i->second.assignments.begin(), i->second.assignments.end());
 		}
diff --git a/source/programcompiler.h b/source/programcompiler.h
index 0ff4f667..ac1f910d 100644
--- a/source/programcompiler.h
+++ b/source/programcompiler.h
@@ -276,6 +276,7 @@ private:
 		virtual void visit(ProgramSyntax::BinaryExpression &);
 		virtual void visit(ProgramSyntax::Assignment &);
 		void record_assignment(ProgramSyntax::VariableDeclaration &, ProgramSyntax::Node &, bool);
+		void clear_assignments(VariableInfo &, bool);
 		virtual void visit(ProgramSyntax::ExpressionStatement &);
 		virtual void visit(ProgramSyntax::StructDeclaration &);
 		virtual void visit(ProgramSyntax::VariableDeclaration &);