From 9bec9da4ec633a541cf6048beed99629fefae2b9 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Fri, 5 Mar 2021 01:18:15 +0200
Subject: [PATCH] Check that variable references refer do declared variables

---
 source/glsl/compiler.cpp           |  1 +
 source/glsl/validate.cpp           | 26 ++++++++++++++++++++++++++
 source/glsl/validate.h             | 11 +++++++++++
 tests/glsl/undeclared.glsl         | 15 +++++++++++++++
 tests/glsl/unlinked_interface.glsl | 25 +++++++++++++++++++++++++
 5 files changed, 78 insertions(+)
 create mode 100644 tests/glsl/undeclared.glsl
 create mode 100644 tests/glsl/unlinked_interface.glsl

diff --git a/source/glsl/compiler.cpp b/source/glsl/compiler.cpp
index f5540139..0f608d6d 100644
--- a/source/glsl/compiler.cpp
+++ b/source/glsl/compiler.cpp
@@ -260,6 +260,7 @@ void Compiler::generate(Stage &stage, Mode mode)
 bool Compiler::validate(Stage &stage)
 {
 	DeclarationValidator().apply(stage);
+	ReferenceValidator().apply(stage);
 
 	for(vector<Diagnostic>::const_iterator i=stage.diagnostics.begin(); i!=stage.diagnostics.end(); ++i)
 		if(i->severity==Diagnostic::ERR)
diff --git a/source/glsl/validate.cpp b/source/glsl/validate.cpp
index 6d0f8e51..6f0869ea 100644
--- a/source/glsl/validate.cpp
+++ b/source/glsl/validate.cpp
@@ -112,6 +112,32 @@ void DeclarationValidator::visit(FunctionDeclaration &func)
 	TraversingVisitor::visit(func);
 }
 
+
+void ReferenceValidator::visit(VariableReference &var)
+{
+	if(!var.declaration)
+		error(var, format("Use of undeclared variable '%s'", var.name));
+	else if(stage->type!=Stage::VERTEX && var.declaration->interface=="in" && !var.declaration->linked_declaration)
+		error(var, format("Use of unlinked input variable '%s'", var.name));
+}
+
+void ReferenceValidator::visit(InterfaceBlockReference &iface)
+{
+	/* An interface block reference without a declaration should be impossible
+	since references are generated based on existing declarations. */
+	if(!iface.declaration)
+		error(iface, format("Use of undeclared interface block '%s'", iface.name));
+	else if(stage->type!=Stage::VERTEX && iface.declaration->interface=="in" && !iface.declaration->linked_block)
+		error(iface, format("Use of unlinked input block '%s'", iface.name));
+}
+
+void ReferenceValidator::visit(VariableDeclaration &var)
+{
+	if(!var.type_declaration)
+		error(var, format("Use of undeclared type '%s'", var.type));
+	TraversingVisitor::visit(var);
+}
+
 } // namespace SL
 } // namespace GL
 } // namespace Msp
diff --git a/source/glsl/validate.h b/source/glsl/validate.h
index c723b995..bf2677e8 100644
--- a/source/glsl/validate.h
+++ b/source/glsl/validate.h
@@ -50,6 +50,17 @@ private:
 	virtual void visit(FunctionDeclaration &);
 };
 
+class ReferenceValidator: private Validator
+{
+public:
+	void apply(Stage &s) { stage = &s; s.content.visit(*this); }
+
+private:
+	virtual void visit(VariableReference &);
+	virtual void visit(InterfaceBlockReference &);
+	virtual void visit(VariableDeclaration &);
+};
+
 } // namespace SL
 } // namespace GL
 } // namespace Msp
diff --git a/tests/glsl/undeclared.glsl b/tests/glsl/undeclared.glsl
new file mode 100644
index 00000000..da888cd3
--- /dev/null
+++ b/tests/glsl/undeclared.glsl
@@ -0,0 +1,15 @@
+uniform Transform
+{
+	mat4 mvp;
+} transform;
+
+#pragma MSP stage(vertex)
+void main()
+{
+	gl_Position = transform.model*position;
+}
+
+/* Expected error:
+<test>:9: Use of undeclared member 'model'
+<test>:9: Use of undeclared variable 'position'
+*/
diff --git a/tests/glsl/unlinked_interface.glsl b/tests/glsl/unlinked_interface.glsl
new file mode 100644
index 00000000..bb90f0db
--- /dev/null
+++ b/tests/glsl/unlinked_interface.glsl
@@ -0,0 +1,25 @@
+uniform sampler2D tex;
+
+#pragma MSP stage(vertex)
+layout(location=0) in vec4 position;
+void main()
+{
+	gl_Position = position;
+}
+
+#pragma MSP stage(fragment)
+in vec2 texcoord;
+in VertexOut
+{
+	vec4 color;
+} vs_out;
+out vec4 frag_color;
+void main()
+{
+	frag_color = texture(tex, texcoord)*vs_out.color;
+}
+
+/* Expected error:
+<test>:19: Use of unlinked input variable 'texcoord'
+<test>:19: Use of unlinked input block 'vs_out'
+*/
-- 
2.43.0