From 948930b171b4d99ba424a979951769f9ef7a6b29 Mon Sep 17 00:00:00 2001
From: Hans-Kristian Arntzen <hans-kristian.arntzen@arm.com>
Date: Sun, 11 Sep 2016 12:36:12 +0200
Subject: [PATCH] Build new IDs for shadow arguments.

---
 spirv_common.hpp |  6 ++++++
 spirv_cross.cpp  | 31 ++++++++++++++++++++++++++++---
 spirv_glsl.cpp   |  4 +---
 3 files changed, 35 insertions(+), 6 deletions(-)

diff --git a/spirv_common.hpp b/spirv_common.hpp
index aab75d75..836993e7 100644
--- a/spirv_common.hpp
+++ b/spirv_common.hpp
@@ -448,6 +448,7 @@ struct SPIRFunction : IVariant
 	// or a global ID.
 	struct CombinedImageSamplerParameter
 	{
+		uint32_t id;
 		uint32_t texture_id;
 		uint32_t sampler_id;
 		bool global_texture;
@@ -457,6 +458,11 @@ struct SPIRFunction : IVariant
 	uint32_t return_type;
 	uint32_t function_type;
 	std::vector<Parameter> arguments;
+
+	// Can be used by backends to add magic arguments.
+	// Currently used by combined image/sampler implementation.
+
+	std::vector<Parameter> shadow_arguments;
 	std::vector<uint32_t> local_variables;
 	uint32_t entry_block = 0;
 	std::vector<uint32_t> blocks;
diff --git a/spirv_cross.cpp b/spirv_cross.cpp
index 998a03b7..0249bbfe 100644
--- a/spirv_cross.cpp
+++ b/spirv_cross.cpp
@@ -2407,7 +2407,7 @@ void Compiler::CombinedImageSamplerHandler::register_combined_image_sampler(SPIR
 	// or a parameter in our own function. If both are global, they will not need a parameter,
 	// otherwise, add it to our list.
 	SPIRFunction::CombinedImageSamplerParameter param = {
-		texture_id, sampler_id, true, true,
+		0u, texture_id, sampler_id, true, true,
 	};
 
 	auto texture_itr = find_if(begin(caller.arguments), end(caller.arguments),
@@ -2437,7 +2437,33 @@ void Compiler::CombinedImageSamplerHandler::register_combined_image_sampler(SPIR
 		               });
 
 	if (itr == end(caller.combined_parameters))
+	{
+		uint32_t id = compiler.increase_bound_by(2);
+		auto type_id = id + 0;
+		auto combined_id = id + 1;
+		auto &base = compiler.expression_type(sampler_id);
+		auto &type = compiler.set<SPIRType>(type_id);
+
+		type = base;
+		type.pointer = true;
+		type.storage = StorageClassUniformConstant;
+
+		// Build new variable.
+		compiler.set<SPIRVariable>(combined_id, type_id, StorageClassFunction, 0);
+
+		// Inherit RelaxedPrecision (and potentially other useful flags if deemed relevant).
+		auto &new_flags = compiler.meta[combined_id].decoration.decoration_flags;
+		auto old_flags = compiler.meta[sampler_id].decoration.decoration_flags;
+		new_flags = old_flags & (1ull << DecorationRelaxedPrecision);
+
+		param.id = combined_id;
+
+		compiler.set_name(combined_id,
+		                  join("SPIRV_Cross_Combined", compiler.to_name(texture_id), compiler.to_name(sampler_id)));
+
 		caller.combined_parameters.push_back(param);
+		caller.shadow_arguments.push_back({ type_id, combined_id, 0u, 0u });
+	}
 }
 
 bool Compiler::CombinedImageSamplerHandler::handle(Op opcode, const uint32_t *args, uint32_t length)
@@ -2552,8 +2578,7 @@ bool Compiler::CombinedImageSamplerHandler::handle(Op opcode, const uint32_t *ar
 		type.storage = StorageClassUniformConstant;
 
 		// Build new variable.
-		auto &var = compiler.set<SPIRVariable>(combined_id, type_id, StorageClassUniformConstant, 0);
-		var.storage = StorageClassUniformConstant;
+		compiler.set<SPIRVariable>(combined_id, type_id, StorageClassUniformConstant, 0);
 
 		// Inherit RelaxedPrecision (and potentially other useful flags if deemed relevant).
 		auto &new_flags = compiler.meta[combined_id].decoration.decoration_flags;
diff --git a/spirv_glsl.cpp b/spirv_glsl.cpp
index 7a735de6..0c8c2a2e 100644
--- a/spirv_glsl.cpp
+++ b/spirv_glsl.cpp
@@ -1905,7 +1905,6 @@ void CompilerGLSL::emit_sampled_image_op(uint32_t result_type, uint32_t result_i
 		if (image_itr != end(args) || sampler_itr != end(args))
 		{
 			// If any parameter originates from a parameter, we will find it in our argument list.
-			uint32_t param_index = 0;
 			bool global_texture = image_itr == end(args);
 			bool global_sampler = sampler_itr == end(args);
 			uint32_t texture_id = global_texture ? image_id : (image_itr - begin(args));
@@ -1920,8 +1919,7 @@ void CompilerGLSL::emit_sampled_image_op(uint32_t result_type, uint32_t result_i
 
 			if (itr != end(combined))
 			{
-				param_index = itr - begin(combined);
-				emit_op(result_type, result_id, join("PARAMETER", param_index), true, false);
+				emit_op(result_type, result_id, to_expression(itr->id), true, false);
 			}
 			else
 			{