From 89de98315588ec89ad66e9a4f3f90bf03e1f7733 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Thu, 11 Nov 2021 12:49:08 +0200
Subject: [PATCH] Propagate locations from existing variables before
 optimization

Uniform location and binding qualifiers should apply to all copies of the
variable even if the one originally containing them is optimized out.
---
 source/glsl/compiler.cpp | 1 +
 source/glsl/finalize.cpp | 8 ++++++--
 source/glsl/finalize.h   | 3 ++-
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/source/glsl/compiler.cpp b/source/glsl/compiler.cpp
index e676fcc8..4e9f94d8 100644
--- a/source/glsl/compiler.cpp
+++ b/source/glsl/compiler.cpp
@@ -75,6 +75,7 @@ void Compiler::compile(Mode mode)
 	for(Stage &s: module->stages)
 		generate(s);
 	ConstantIdAssigner().apply(*module, features);
+	LocationAllocator().apply(*module, features, false);
 
 	for(Stage &s: module->stages)
 		validate(s);
diff --git a/source/glsl/finalize.cpp b/source/glsl/finalize.cpp
index 7eb0165d..cb304aa3 100644
--- a/source/glsl/finalize.cpp
+++ b/source/glsl/finalize.cpp
@@ -62,8 +62,9 @@ void StructOrganizer::visit(VariableDeclaration &var)
 }
 
 
-void LocationAllocator::apply(Module &module, const Features &features)
+void LocationAllocator::apply(Module &module, const Features &features, bool a)
 {
+	alloc_new = a;
 	for(Stage &s: module.stages)
 		apply(s);
 
@@ -111,6 +112,9 @@ void LocationAllocator::allocate_locations(const string &iface)
 			}
 		}
 
+		if(!alloc_new)
+			continue;
+
 		set<unsigned> &used = used_locations[(*i)->interface];
 
 		unsigned size = LocationCounter().apply(**i);
@@ -142,7 +146,7 @@ void LocationAllocator::bind_uniform(RefPtr<Layout> &layout, const string &name,
 	auto i = uniforms.find(name);
 	if(i!=uniforms.end() && i->second.bind_point>=0)
 		add_layout_qualifier(layout, Layout::Qualifier("binding", i->second.bind_point));
-	else
+	else if(alloc_new)
 	{
 		set<unsigned> &used = used_bindings[0];
 
diff --git a/source/glsl/finalize.h b/source/glsl/finalize.h
index bde0618a..ab4276f5 100644
--- a/source/glsl/finalize.h
+++ b/source/glsl/finalize.h
@@ -36,6 +36,7 @@ private:
 		Uniform(): location(-1), desc_set(-1), bind_point(-1) { }
 	};
 
+	bool alloc_new = true;
 	std::map<std::string, std::set<unsigned> > used_locations;
 	std::map<std::string, Uniform> uniforms;
 	std::map<unsigned, std::set<unsigned> > used_bindings;
@@ -44,7 +45,7 @@ private:
 	std::vector<InterfaceBlock *> unbound_blocks;
 
 public:
-	void apply(Module &, const Features &);
+	void apply(Module &, const Features &, bool = true);
 private:
 	void apply(Stage &);
 
-- 
2.43.0