From dfcf8ebc329b79c369b88bdbeb982480aa5fc12a Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Mon, 5 Apr 2021 14:49:41 +0300
Subject: [PATCH] Always use member access for interface blocks, even anonymous
 ones

Having variable references magically refer to variables inside interface
blocks causes trouble when generating SPIR-V.

This currently breaks one test case because UnusedVariableRemover can't
track access chains.
---
 source/glsl/optimize.cpp | 16 ++------------
 source/glsl/output.cpp   | 12 ++++++++---
 source/glsl/output.h     |  1 +
 source/glsl/resolve.cpp  | 46 ++++++++++++++++++++++++++--------------
 4 files changed, 42 insertions(+), 33 deletions(-)

diff --git a/source/glsl/optimize.cpp b/source/glsl/optimize.cpp
index d7558ebd..475e8b64 100644
--- a/source/glsl/optimize.cpp
+++ b/source/glsl/optimize.cpp
@@ -997,10 +997,6 @@ bool UnusedVariableRemover::apply(Stage &s)
 		if(i->used_by.empty())
 			unused_nodes.insert(i->node);
 
-	for(map<string, InterfaceBlock *>::const_iterator i=s.interface_blocks.begin(); i!=s.interface_blocks.end(); ++i)
-		if(i->second->instance_name.empty())
-			unused_nodes.insert(i->second);
-
 	for(BlockVariableMap::const_iterator i=variables.begin(); i!=variables.end(); ++i)
 	{
 		if(i->second.output)
@@ -1153,16 +1149,8 @@ void UnusedVariableRemover::visit(VariableDeclaration &var)
 
 void UnusedVariableRemover::visit(InterfaceBlock &iface)
 {
-	if(iface.instance_name.empty())
-	{
-		SetForScope<InterfaceBlock *> set_block(interface_block, &iface);
-		iface.struct_declaration->members.visit(*this);
-	}
-	else
-	{
-		VariableInfo &var_info = variables[&iface];
-		var_info.output = (iface.interface=="out" && (iface.linked_block || !iface.block_name.compare(0, 3, "gl_")));
-	}
+	VariableInfo &var_info = variables[&iface];
+	var_info.output = (iface.interface=="out" && (iface.linked_block || !iface.block_name.compare(0, 3, "gl_")));
 }
 
 void UnusedVariableRemover::merge_variables(const BlockVariableMap &other_vars)
diff --git a/source/glsl/output.cpp b/source/glsl/output.cpp
index 1d82cae6..38adb5bd 100644
--- a/source/glsl/output.cpp
+++ b/source/glsl/output.cpp
@@ -14,7 +14,8 @@ Formatter::Formatter():
 	source_line(1),
 	indent(0),
 	parameter_list(false),
-	omit_builtin(false)
+	omit_builtin(false),
+	r_empty_name(false)
 { }
 
 const string &Formatter::apply(Stage &s)
@@ -154,17 +155,22 @@ void Formatter::visit(Literal &literal)
 void Formatter::visit(VariableReference &var)
 {
 	append(var.name);
+	r_empty_name = false;
 }
 
 void Formatter::visit(InterfaceBlockReference &iface)
 {
-	append(iface.name);
+	r_empty_name = iface.declaration->instance_name.empty();
+	if(!r_empty_name)
+		append(iface.declaration->instance_name);
 }
 
 void Formatter::visit(MemberAccess &memacc)
 {
 	visit_expression(*memacc.left, memacc.oper, false);
-	append(format(".%s", memacc.member));
+	if(!r_empty_name)
+		append('.');
+	append(memacc.member);
 }
 
 void Formatter::visit(Swizzle &swizzle)
diff --git a/source/glsl/output.h b/source/glsl/output.h
index 6bdb1ab7..ef936987 100644
--- a/source/glsl/output.h
+++ b/source/glsl/output.h
@@ -20,6 +20,7 @@ private:
 	unsigned indent;
 	bool parameter_list;
 	bool omit_builtin;
+	bool r_empty_name;
 
 public:
 	Formatter();
diff --git a/source/glsl/resolve.cpp b/source/glsl/resolve.cpp
index 8bfe635e..c5a507a2 100644
--- a/source/glsl/resolve.cpp
+++ b/source/glsl/resolve.cpp
@@ -226,28 +226,42 @@ void VariableResolver::visit(VariableReference &var)
 	{
 		const map<string, InterfaceBlock *> &blocks = stage->interface_blocks;
 		map<string, InterfaceBlock *>::const_iterator i = blocks.find(var.name);
+		if(i==blocks.end())
+		{
+			// Look for the variable in anonymous interface blocks.
+			for(i=blocks.begin(); i!=blocks.end(); ++i)
+				if(i->second->instance_name.empty() && i->second->struct_declaration)
+					if(i->second->struct_declaration->members.variables.count(var.name))
+						break;
+		}
+
 		if(i!=blocks.end())
 		{
-			/* The name refers to an interface block with an instance name rather
-			than a variable.  Prepare a new syntax tree node accordingly. */
+			/* The name refers to either an interface block with an instance name
+			or a variable declared inside an anonymous interface block.  Prepare
+			new syntax tree nodes accordingly. */
 			InterfaceBlockReference *iface_ref = new InterfaceBlockReference;
 			iface_ref->source = var.source;
 			iface_ref->line = var.line;
-			iface_ref->name = var.name;
 			iface_ref->declaration = i->second;
-			r_replacement_expr = iface_ref;
-		}
-		else
-		{
-			// Look for the variable in anonymous interface blocks.
-			for(i=blocks.begin(); (!declaration && i!=blocks.end()); ++i)
-				if(i->second->instance_name.empty() && i->second->struct_declaration)
-				{
-					const map<string, VariableDeclaration *> &iface_vars = i->second->struct_declaration->members.variables;
-					map<string, VariableDeclaration *>::const_iterator j = iface_vars.find(var.name);
-					if(j!=iface_vars.end())
-						declaration = j->second;
-				}
+
+			if(i->second->instance_name.empty())
+			{
+				iface_ref->name = format("%s %s", i->second->interface, i->second->block_name);
+
+				MemberAccess *memacc = new MemberAccess;
+				memacc->source = var.source;
+				memacc->line = var.line;
+				memacc->left = iface_ref;
+				memacc->member = var.name;
+
+				r_replacement_expr = memacc;
+			}
+			else
+			{
+				iface_ref->name = var.name;
+				r_replacement_expr = iface_ref;
+			}
 		}
 	}
 
-- 
2.43.0