diff --git a/src/Pipeline/SpirvShader.cpp b/src/Pipeline/SpirvShader.cpp
index 74c0a22..e7845c3 100644
--- a/src/Pipeline/SpirvShader.cpp
+++ b/src/Pipeline/SpirvShader.cpp
@@ -475,7 +475,7 @@
 		// Simplifying assumptions (to be satisfied by earlier transformations)
 		// - The only input/output OpVariables present are those used by the entrypoint
 
-		Object::ID entryPointFunctionId;
+		Function::ID currentFunction;
 		Block::ID currentBlock;
 		InsnIterator blockStart;
 
@@ -488,13 +488,13 @@
 			case spv::OpEntryPoint:
 			{
 				auto executionModel = spv::ExecutionModel(insn.word(1));
-				auto id = Object::ID(insn.word(2));
+				auto id = Function::ID(insn.word(2));
 				auto name = insn.string(3);
 				auto stage = executionModelToStage(executionModel);
 				if (stage == pipelineStage && strcmp(name, entryPointName) == 0)
 				{
-					ASSERT_MSG(entryPointFunctionId == 0, "Duplicate entry point with name '%s' and stage %d", name, int(stage));
-					entryPointFunctionId = id;
+					ASSERT_MSG(entryPoint == 0, "Duplicate entry point with name '%s' and stage %d", name, int(stage));
+					entryPoint = id;
 				}
 				break;
 			}
@@ -607,8 +607,10 @@
 			case spv::OpUnreachable:
 			{
 				ASSERT(currentBlock.value() != 0);
+				ASSERT(currentFunction.value() != 0);
+
 				auto blockEnd = insn; blockEnd++;
-				blocks[currentBlock] = Block(blockStart, blockEnd);
+				functions[currentFunction].blocks[currentBlock] = Block(blockStart, blockEnd);
 				currentBlock = Block::ID(0);
 
 				if (opcode == spv::OpKill)
@@ -791,39 +793,35 @@
 
 			case spv::OpFunction:
 			{
-				auto functionId = Object::ID(insn.word(2));
-				if (functionId == entryPointFunctionId)
+				auto functionId = Function::ID(insn.word(2));
+				ASSERT_MSG(currentFunction == 0, "Functions %d and %d overlap", currentFunction.value(), functionId.value());
+				currentFunction = functionId;
+				auto &function = functions[functionId];
+				function.result = Type::ID(insn.word(1));
+				function.type = Type::ID(insn.word(4));
+				// Scan forward to find the function's label.
+				for (auto it = insn; it != end() && function.entry == 0; it++)
 				{
-					// Scan forward to find the function's label.
-					for (auto it = insn; it != end() && entryPointBlockId == 0; it++)
+					switch (it.opcode())
 					{
-						switch (it.opcode())
-						{
-						case spv::OpFunction:
-						case spv::OpFunctionParameter:
-							break;
-						case spv::OpLabel:
-							entryPointBlockId = Block::ID(it.word(1));
-							break;
-						default:
-							WARN("Unexpected opcode '%s' following OpFunction", OpcodeName(it.opcode()).c_str());
-						}
+					case spv::OpFunction:
+					case spv::OpFunctionParameter:
+						break;
+					case spv::OpLabel:
+						function.entry = Block::ID(it.word(1));
+						break;
+					default:
+						WARN("Unexpected opcode '%s' following OpFunction", OpcodeName(it.opcode()).c_str());
 					}
 				}
-				else
-				{
-					// All non-entry point functions should be inlined into an
-					// entry point function.
-					// This isn't the target entry point, so must be another
-					// entry point that we are not interested in. Just skip it.
-					for (; insn != end() && insn.opcode() != spv::OpFunctionEnd; insn++) {}
-				}
-
+				ASSERT_MSG(function.entry != 0, "Function<%d> has no label", currentFunction.value());
 				break;
 			}
+
 			case spv::OpFunctionEnd:
-				// Due to preprocessing, the entrypoint and its function provide no value.
+				currentFunction = 0;
 				break;
+
 			case spv::OpExtInstImport:
 			{
 				// We will only support the GLSL 450 extended instruction set, so no point in tracking the ID we assign it.
@@ -1062,47 +1060,10 @@
 			}
 		}
 
-		ASSERT_MSG(entryPointFunctionId != 0, "Entry point '%s' not found", entryPointName);
-		AssignBlockFields();
-	}
-
-	void SpirvShader::TraverseReachableBlocks(Block::ID id, SpirvShader::Block::Set& reachable)
-	{
-		if (reachable.count(id) == 0)
+		ASSERT_MSG(entryPoint != 0, "Entry point '%s' not found", entryPointName);
+		for (auto &it : functions)
 		{
-			reachable.emplace(id);
-			for (auto out : getBlock(id).outs)
-			{
-				TraverseReachableBlocks(out, reachable);
-			}
-		}
-	}
-
-	void SpirvShader::AssignBlockFields()
-	{
-		Block::Set reachable;
-		TraverseReachableBlocks(entryPointBlockId, reachable);
-
-		for (auto &it : blocks)
-		{
-			auto &blockId = it.first;
-			auto &block = it.second;
-			if (reachable.count(blockId) > 0)
-			{
-				for (auto &outId : it.second.outs)
-				{
-					auto outIt = blocks.find(outId);
-					ASSERT_MSG(outIt != blocks.end(), "Block %d has a non-existent out %d", blockId.value(), outId.value());
-					auto &out = outIt->second;
-					out.ins.emplace(blockId);
-				}
-				if (block.kind == Block::Loop)
-				{
-					auto mergeIt = blocks.find(block.mergeBlock);
-					ASSERT_MSG(mergeIt != blocks.end(), "Loop block %d has a non-existent merge block %d", blockId.value(), block.mergeBlock.value());
-					mergeIt->second.isLoopMerge = true;
-				}
-			}
+			it.second.AssignBlockFields();
 		}
 	}
 
@@ -2043,7 +2004,7 @@
 
 	void SpirvShader::emit(SpirvRoutine *routine, RValue<SIMD::Int> const &activeLaneMask, const vk::DescriptorSet::Bindings &descriptorSets) const
 	{
-		EmitState state(routine, activeLaneMask, descriptorSets, robustBufferAccess);
+		EmitState state(routine, entryPoint, activeLaneMask, descriptorSets, robustBufferAccess);
 
 		// Emit everything up to the first label
 		// TODO: Separate out dispatch of block from non-block instructions?
@@ -2056,13 +2017,14 @@
 			EmitInstruction(insn, &state);
 		}
 
-		// Emit all the blocks starting from entryPointBlockId.
-		EmitBlocks(entryPointBlockId, &state);
+		// Emit all the blocks starting from entryPoint.
+		EmitBlocks(getFunction(entryPoint).entry, &state);
 	}
 
 	void SpirvShader::EmitBlocks(Block::ID id, EmitState *state, Block::ID ignore /* = 0 */) const
 	{
 		auto oldPending = state->pending;
+		auto &function = getFunction(state->function);
 
 		std::deque<Block::ID> pending;
 		state->pending = &pending;
@@ -2071,7 +2033,7 @@
 		{
 			auto id = pending.front();
 
-			auto const &block = getBlock(id);
+			auto const &block = function.getBlock(id);
 			if (id == ignore)
 			{
 				pending.pop_front();
@@ -2080,7 +2042,7 @@
 
 			// Ensure all dependency blocks have been generated.
 			auto depsDone = true;
-			ForeachBlockDependency(id, [&](Block::ID dep)
+			function.ForeachBlockDependency(id, [&](Block::ID dep)
 			{
 				if (state->visited.count(dep) == 0)
 				{
@@ -2138,30 +2100,18 @@
 		}
 	}
 
-	void SpirvShader::ForeachBlockDependency(Block::ID blockId, std::function<void(Block::ID)> f) const
-	{
-		auto block = getBlock(blockId);
-		for (auto dep : block.ins)
-		{
-			if (block.kind != Block::Loop ||                 // if not a loop...
-				!existsPath(blockId, dep, block.mergeBlock)) // or a loop and not a loop back edge
-			{
-				f(dep);
-			}
-		}
-	}
-
 	void SpirvShader::EmitNonLoop(EmitState *state) const
 	{
+		auto &function = getFunction(state->function);
 		auto blockId = state->currentBlock;
-		auto block = getBlock(blockId);
+		auto block = function.getBlock(blockId);
 
 		if (!state->visited.emplace(blockId).second)
 		{
 			return; // Already generated this block.
 		}
 
-		if (blockId != entryPointBlockId)
+		if (blockId != function.entry)
 		{
 			// Set the activeLaneMask.
 			SIMD::Int activeLaneMask(0);
@@ -2186,10 +2136,11 @@
 
 	void SpirvShader::EmitLoop(EmitState *state) const
 	{
+		auto &function = getFunction(state->function);
 		auto blockId = state->currentBlock;
-		auto &block = getBlock(blockId);
+		auto &block = function.getBlock(blockId);
 		auto mergeBlockId = block.mergeBlock;
-		auto &mergeBlock = getBlock(mergeBlockId);
+		auto &mergeBlock = function.getBlock(mergeBlockId);
 
 		if (!state->visited.emplace(blockId).second)
 		{
@@ -2200,7 +2151,7 @@
 		std::unordered_set<Block::ID> loopBlocks;
 		for (auto in : block.ins)
 		{
-			if (!existsPath(blockId, in, mergeBlockId)) // if not a loop back-edge
+			if (!function.ExistsPath(blockId, in, mergeBlockId)) // if not a loop back-edge
 			{
 				incomingBlocks.emplace(in);
 			}
@@ -2231,7 +2182,7 @@
 		// mergeActiveLaneMasks contains edge lane masks for the merge block.
 		// This is the union of all edge masks across all iterations of the loop.
 		std::unordered_map<Block::ID, SIMD::Int> mergeActiveLaneMasks;
-		for (auto in : getBlock(mergeBlockId).ins)
+		for (auto in : function.getBlock(mergeBlockId).ins)
 		{
 			mergeActiveLaneMasks.emplace(in, SIMD::Int(0));
 		}
@@ -2274,14 +2225,14 @@
 		loopActiveLaneMask = SIMD::Int(0);
 		for (auto in : block.ins)
 		{
-			if (existsPath(blockId, in, mergeBlockId))
+			if (function.ExistsPath(blockId, in, mergeBlockId))
 			{
 				loopActiveLaneMask |= GetActiveLaneMaskEdge(state, in, blockId);
 			}
 		}
 
 		// Add active lanes to the merge lane mask.
-		for (auto in : getBlock(mergeBlockId).ins)
+		for (auto in : function.getBlock(mergeBlockId).ins)
 		{
 			auto edge = Block::Edge{in, mergeBlockId};
 			auto it = state->edgeActiveLaneMasks.find(edge);
@@ -4638,7 +4589,8 @@
 
 	SpirvShader::EmitResult SpirvShader::EmitBranchConditional(InsnIterator insn, EmitState *state) const
 	{
-		auto block = getBlock(state->currentBlock);
+		auto &function = getFunction(state->function);
+		auto block = function.getBlock(state->currentBlock);
 		ASSERT(block.branchInstruction == insn);
 
 		auto condId = Object::ID(block.branchInstruction.word(1));
@@ -4658,7 +4610,8 @@
 
 	SpirvShader::EmitResult SpirvShader::EmitSwitch(InsnIterator insn, EmitState *state) const
 	{
-		auto block = getBlock(state->currentBlock);
+		auto &function = getFunction(state->function);
+		auto block = function.getBlock(state->currentBlock);
 		ASSERT(block.branchInstruction == insn);
 
 		auto selId = Object::ID(block.branchInstruction.word(1));
@@ -4712,7 +4665,8 @@
 
 	SpirvShader::EmitResult SpirvShader::EmitPhi(InsnIterator insn, EmitState *state) const
 	{
-		auto currentBlock = getBlock(state->currentBlock);
+		auto &function = getFunction(state->function);
+		auto currentBlock = function.getBlock(state->currentBlock);
 		if (!currentBlock.isLoopMerge)
 		{
 			// If this is a loop merge block, then don't attempt to update the
@@ -6356,7 +6310,61 @@
 		}
 	}
 
-	bool SpirvShader::existsPath(Block::ID from, Block::ID to, Block::ID notPassingThrough) const
+
+	void SpirvShader::Function::TraverseReachableBlocks(Block::ID id, SpirvShader::Block::Set& reachable)
+	{
+		if (reachable.count(id) == 0)
+		{
+			reachable.emplace(id);
+			for (auto out : getBlock(id).outs)
+			{
+				TraverseReachableBlocks(out, reachable);
+			}
+		}
+	}
+
+	void SpirvShader::Function::AssignBlockFields()
+	{
+		Block::Set reachable;
+		TraverseReachableBlocks(entry, reachable);
+
+		for (auto &it : blocks)
+		{
+			auto &blockId = it.first;
+			auto &block = it.second;
+			if (reachable.count(blockId) > 0)
+			{
+				for (auto &outId : it.second.outs)
+				{
+					auto outIt = blocks.find(outId);
+					ASSERT_MSG(outIt != blocks.end(), "Block %d has a non-existent out %d", blockId.value(), outId.value());
+					auto &out = outIt->second;
+					out.ins.emplace(blockId);
+				}
+				if (block.kind == Block::Loop)
+				{
+					auto mergeIt = blocks.find(block.mergeBlock);
+					ASSERT_MSG(mergeIt != blocks.end(), "Loop block %d has a non-existent merge block %d", blockId.value(), block.mergeBlock.value());
+					mergeIt->second.isLoopMerge = true;
+				}
+			}
+		}
+	}
+
+	void SpirvShader::Function::ForeachBlockDependency(Block::ID blockId, std::function<void(Block::ID)> f) const
+	{
+		auto block = getBlock(blockId);
+		for (auto dep : block.ins)
+		{
+			if (block.kind != Block::Loop ||                 // if not a loop...
+				!ExistsPath(blockId, dep, block.mergeBlock)) // or a loop and not a loop back edge
+			{
+				f(dep);
+			}
+		}
+	}
+
+	bool SpirvShader::Function::ExistsPath(Block::ID from, Block::ID to, Block::ID notPassingThrough) const
 	{
 		// TODO: Optimize: This can be cached on the block.
 		Block::Set seen;
diff --git a/src/Pipeline/SpirvShader.hpp b/src/Pipeline/SpirvShader.hpp
index 995419e..d1c627b 100644
--- a/src/Pipeline/SpirvShader.hpp
+++ b/src/Pipeline/SpirvShader.hpp
@@ -541,6 +541,45 @@
 			InsnIterator end_;
 		};
 
+		class Function
+		{
+		public:
+			using ID = SpirvID<Function>;
+
+			// Walks all reachable the blocks starting from id adding them to
+			// reachable.
+			void TraverseReachableBlocks(Block::ID id, Block::Set& reachable);
+
+			// AssignBlockFields() performs the following for all reachable blocks:
+			// * Assigns Block::ins with the identifiers of all blocks that contain
+			//   this block in their Block::outs.
+			// * Sets Block::isLoopMerge to true if the block is the merge of a
+			//   another loop block.
+			void AssignBlockFields();
+
+			// ForeachBlockDependency calls f with each dependency of the given
+			// block. A dependency is an incoming block that is not a loop-back
+			// edge.
+			void ForeachBlockDependency(Block::ID blockId, std::function<void(Block::ID)> f) const;
+
+			// ExistsPath returns true if there's a direct or indirect flow from
+			// the 'from' block to the 'to' block that does not pass through
+			// notPassingThrough.
+			bool ExistsPath(Block::ID from, Block::ID to, Block::ID notPassingThrough) const;
+
+			Block const &getBlock(Block::ID id) const
+			{
+				auto it = blocks.find(id);
+				ASSERT_MSG(it != blocks.end(), "Unknown block %d", id.value());
+				return it->second;
+			}
+
+			Block::ID entry; // function entry point block.
+			HandleMap<Block> blocks; // blocks belonging to this function.
+			Type::ID type; // type of the function.
+			Type::ID result; // return type.
+		};
+
 		struct TypeOrObject {}; // Dummy struct to represent a Type or Object.
 
 		// TypeOrObjectID is an identifier that represents a Type or an Object,
@@ -623,7 +662,7 @@
 		// shader entry point represented by this object.
 		uint64_t getSerialID() const
 		{
-			return  ((uint64_t)entryPointBlockId.value() << 32) | codeSerialID;
+			return  ((uint64_t)entryPoint.value() << 32) | codeSerialID;
 		}
 
 		SpirvShader(uint32_t codeSerialID,
@@ -816,10 +855,10 @@
 			return it->second;
 		}
 
-		Block const &getBlock(Block::ID id) const
+		Function const &getFunction(Function::ID id) const
 		{
-			auto it = blocks.find(id);
-			ASSERT_MSG(it != blocks.end(), "Unknown block %d", id.value());
+			auto it = functions.find(id);
+			ASSERT_MSG(it != functions.end(), "Unknown function %d", id.value());
 			return it->second;
 		}
 
@@ -828,22 +867,11 @@
 		Modes modes;
 		HandleMap<Type> types;
 		HandleMap<Object> defs;
-		HandleMap<Block> blocks;
-		Block::ID entryPointBlockId; // Block of the entry point function.
+		HandleMap<Function> functions;
+		Function::ID entryPoint;
 
 		const bool robustBufferAccess = true;
 
-		// Walks all reachable the blocks starting from id adding them to
-		// reachable.
-		void TraverseReachableBlocks(Block::ID id, Block::Set& reachable);
-
-		// AssignBlockFields() performs the following for all reachable blocks:
-		// * Assigns Block::ins with the identifiers of all blocks that contain
-		//   this block in their Block::outs.
-		// * Sets Block::isLoopMerge to true if the block is the merge of a
-		//   another loop block.
-		void AssignBlockFields();
-
 		// DeclareType creates a Type for the given OpTypeX instruction, storing
 		// it into the types map. It is called from the analysis pass (constructor).
 		void DeclareType(InsnIterator insn);
@@ -923,8 +951,13 @@
 		class EmitState
 		{
 		public:
-			EmitState(SpirvRoutine *routine, RValue<SIMD::Int> activeLaneMask, const vk::DescriptorSet::Bindings &descriptorSets, bool robustBufferAccess)
+			EmitState(SpirvRoutine *routine,
+					Function::ID function,
+					RValue<SIMD::Int> activeLaneMask,
+					const vk::DescriptorSet::Bindings &descriptorSets,
+					bool robustBufferAccess)
 				: routine(routine),
+				  function(function),
 				  activeLaneMaskValue(activeLaneMask.value),
 				  descriptorSets(descriptorSets),
 				  robust(robustBufferAccess)
@@ -954,6 +987,7 @@
 			void addActiveLaneMaskEdge(Block::ID from, Block::ID to, RValue<SIMD::Int> mask);
 
 			SpirvRoutine *routine = nullptr; // The current routine being built.
+			Function::ID function; // The current function being built.
 			rr::Value *activeLaneMaskValue = nullptr; // The current active lane mask.
 			Block::ID currentBlock; // The current block being built.
 			Block::Set visited; // Blocks already built.
@@ -1055,21 +1089,11 @@
 		// Returns the *component* offset in the literal for the given access chain.
 		uint32_t WalkLiteralAccessChain(Type::ID id, uint32_t numIndexes, uint32_t const *indexes) const;
 
-		// existsPath returns true if there's a direct or indirect flow from
-		// the 'from' block to the 'to' block that does not pass through
-		// notPassingThrough.
-		bool existsPath(Block::ID from, Block::ID to, Block::ID notPassingThrough) const;
-
 		// Lookup the active lane mask for the edge from -> to.
 		// If from is unreachable, then a mask of all zeros is returned.
 		// Asserts if from is reachable and the edge does not exist.
 		RValue<SIMD::Int> GetActiveLaneMaskEdge(EmitState *state, Block::ID from, Block::ID to) const;
 
-		// ForeachBlockDependency calls f with each dependency of the given
-		// block. A dependency is an incoming block that is not a loop-back
-		// edge.
-		void ForeachBlockDependency(Block::ID blockId, std::function<void(Block::ID)> f) const;
-
 		// Emit all the unvisited blocks (except for ignore) in DFS order,
 		// starting with id.
 		void EmitBlocks(Block::ID id, EmitState *state, Block::ID ignore = 0) const;
diff --git a/src/Pipeline/SpirvShaderSampling.cpp b/src/Pipeline/SpirvShaderSampling.cpp
index 87bba39..e02c32a 100644
--- a/src/Pipeline/SpirvShaderSampling.cpp
+++ b/src/Pipeline/SpirvShaderSampling.cpp
@@ -117,7 +117,7 @@
 SpirvShader::ImageSampler *SpirvShader::emitSamplerFunction(ImageInstruction instruction, const Sampler &samplerState)
 {
 	// TODO(b/129523279): Hold a separate mutex lock for the sampler being built.
-	Function<Void(Pointer<Byte>, Pointer<Byte>, Pointer<SIMD::Float>, Pointer<SIMD::Float>, Pointer<Byte>)> function;
+	rr::Function<Void(Pointer<Byte>, Pointer<Byte>, Pointer<SIMD::Float>, Pointer<SIMD::Float>, Pointer<Byte>)> function;
 	{
 		Pointer<Byte> texture = function.Arg<0>();
 		Pointer<Byte> sampler = function.Arg<1>();