Fix deep call hierarchies in CombinedImageSamplerUsageHandler.

spirv_cross.cpp

@@ -3361,26 +3361,6 @@ void Compiler::analyze_sampler_comparison_states()
 	comparison_samplers = move(handler.comparison_samplers);
 }
 
-uint32_t Compiler::CombinedImageSamplerUsageHandler::map_to_global_variable(uint32_t id, bool map_parameter) const
-{
-	const auto remap = [](const unordered_map<uint32_t, uint32_t> &map, uint32_t variable_id) -> uint32_t {
-		auto itr = map.find(variable_id);
-		if (itr != end(map))
-			return itr->second;
-		else
-			return variable_id;
-	};
-
-	// Attempt to remap an ID to a variable if it was loaded by OpLoad.
-	id = remap(to_variable_map, id);
-	if (map_parameter)
-	{
-		// Attempt to remap a variable ID to a global ID if the variable ID is a function parameter.
-		id = remap(param_to_global, id);
-	}
-	return id;
-}
-
 bool Compiler::CombinedImageSamplerUsageHandler::begin_function_scope(const uint32_t *args, uint32_t length)
 {
 	if (length < 3)
@@ -3390,32 +3370,37 @@ bool Compiler::CombinedImageSamplerUsageHandler::begin_function_scope(const uint
 	const auto *arg = &args[3];
 	length -= 3;
 
-	// Do not need a stack for param_to_global since we cannot recurse, and parameter IDs for different functions
-	// must be different.
 	for (uint32_t i = 0; i < length; i++)
 	{
 		auto &argument = func.arguments[i];
-		param_to_global[argument.id] = map_to_global_variable(arg[i], true);
+		dependency_hierarchy[argument.id].insert(arg[i]);
 	}
 
 	return true;
 }
 
+void Compiler::CombinedImageSamplerUsageHandler::add_hierarchy_to_comparison_samplers(uint32_t sampler)
+{
+	// Traverse the variable dependency hierarchy and tag everything in its path with comparison samplers.
+	comparison_samplers.insert(sampler);
+	for (auto &samp : dependency_hierarchy[sampler])
+		add_hierarchy_to_comparison_samplers(samp);
+}
+
 bool Compiler::CombinedImageSamplerUsageHandler::handle(Op opcode, const uint32_t *args, uint32_t length)
 {
 	switch (opcode)
 	{
+	case OpAccessChain:
+	case OpInBoundsAccessChain:
 	case OpLoad:
 	{
 		if (length < 3)
 			return false;
-		// Needed so we are able to map the loaded OpSampler to its original variable.
-		to_variable_map[args[1]] = args[2];
+		dependency_hierarchy[args[1]].insert(args[2]);
 		break;
 	}
 
-	// TODO: Deal with arrays of images and samplers?
-
 	case OpSampledImage:
 	{
 		if (length < 4)
@@ -3427,12 +3412,7 @@ bool Compiler::CombinedImageSamplerUsageHandler::handle(Op opcode, const uint32_
 		{
 			// This sampler must be a SamplerComparisionState, and not a regular SamplerState.
 			uint32_t sampler = args[3];
-
-			// Make sure we tag both parameters and global variables here.
-			uint32_t sampler_variable = map_to_global_variable(sampler, false);
-			comparison_samplers.insert(sampler_variable);
-			sampler_variable = map_to_global_variable(sampler, true);
-			comparison_samplers.insert(sampler_variable);
+			add_hierarchy_to_comparison_samplers(sampler);
 		}
 		return true;
 	}

spirv_cross.hpp

@@ -621,6 +621,10 @@ protected:
 	    SPIRFunction &entry, const CFG &cfg,
 	    const std::unordered_map<uint32_t, std::unordered_set<uint32_t>> &variable_to_blocks);
 
+	// If a variable ID or parameter ID is found in this set, a sampler is actually a shadow/comparison sampler.
+	// SPIR-V does not support this distinction, so we must keep track of this information outside the type system.
+	// There might be unrelated IDs found in this set which do not correspond to actual variables.
+	// This set should only be queried for the existence of samplers which are already known to be variables or parameter IDs.
 	std::unordered_set<uint32_t> comparison_samplers;
 	void analyze_sampler_comparison_states();
 	struct CombinedImageSamplerUsageHandler : OpcodeHandler
@@ -634,10 +638,10 @@ protected:
 		bool handle(spv::Op opcode, const uint32_t *args, uint32_t length) override;
 		Compiler &compiler;
 
-		std::unordered_map<uint32_t, uint32_t> to_variable_map;
-		std::unordered_map<uint32_t, uint32_t> param_to_global;
+		std::unordered_map<uint32_t, std::unordered_set<uint32_t>> dependency_hierarchy;
 		std::unordered_set<uint32_t> comparison_samplers;
-		uint32_t map_to_global_variable(uint32_t id, bool map_parameter) const;
+
+		void add_hierarchy_to_comparison_samplers(uint32_t sampler);
 	};
 };
 }

spirv_glsl.cpp

@@ -5830,7 +5830,7 @@ string CompilerGLSL::argument_decl(const SPIRFunction::Parameter &arg)
 	if (type.basetype == SPIRType::Sampler)
 	{
 		tmp_type = &fake_type;
-		fake_type.basetype = SPIRType::Sampler;
+		fake_type = type;
 		fake_type.image.depth = comparison_samplers.count(arg.id) != 0;
 	}
 
@@ -5849,7 +5849,7 @@ string CompilerGLSL::variable_decl(const SPIRVariable &variable)
 	if (type.basetype == SPIRType::Sampler)
 	{
 		tmp_type = &fake_type;
-		fake_type.basetype = SPIRType::Sampler;
+		fake_type = type;
 		fake_type.image.depth = comparison_samplers.count(variable.self) != 0;
 	}