diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 70979a2..10605fd 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -408,6 +408,7 @@
     writer/spirv/builder_test.cc
     writer/spirv/builder_type_test.cc
     writer/spirv/builder_entry_point_test.cc
+    writer/spirv/builder_function_test.cc
     writer/spirv/instruction_test.cc
     writer/spirv/operand_test.cc
     writer/spirv/spv_dump.cc
diff --git a/src/ast/function.cc b/src/ast/function.cc
index 4d13d13..4aa7c52 100644
--- a/src/ast/function.cc
+++ b/src/ast/function.cc
@@ -14,6 +14,8 @@
 
 #include "src/ast/function.h"
 
+#include <sstream>
+
 namespace tint {
 namespace ast {
 
@@ -83,5 +85,16 @@
   out << "}" << std::endl;
 }
 
+std::string Function::type_name() const {
+  std::ostringstream out;
+
+  out << "__func" + return_type_->type_name();
+  for (const auto& param : params_) {
+    out << param->type()->type_name();
+  }
+
+  return out.str();
+}
+
 }  // namespace ast
 }  // namespace tint
diff --git a/src/ast/function.h b/src/ast/function.h
index 691f059..71afe7c 100644
--- a/src/ast/function.h
+++ b/src/ast/function.h
@@ -94,6 +94,9 @@
   /// @param indent number of spaces to indent the node when writing
   void to_str(std::ostream& out, size_t indent) const override;
 
+  /// @returns the type name for this function
+  std::string type_name() const;
+
  private:
   Function(const Function&) = delete;
 
diff --git a/src/ast/function_test.cc b/src/ast/function_test.cc
index d2bd9aa..e4506a5 100644
--- a/src/ast/function_test.cc
+++ b/src/ast/function_test.cc
@@ -16,6 +16,7 @@
 
 #include "gtest/gtest.h"
 #include "src/ast/nop_statement.h"
+#include "src/ast/type/f32_type.h"
 #include "src/ast/type/i32_type.h"
 #include "src/ast/type/void_type.h"
 #include "src/ast/variable.h"
@@ -202,5 +203,27 @@
 )");
 }
 
+TEST_F(FunctionTest, TypeName) {
+  type::VoidType void_type;
+
+  Function f("func", {}, &void_type);
+  EXPECT_EQ(f.type_name(), "__func__void");
+}
+
+TEST_F(FunctionTest, TypeName_WithParams) {
+  type::VoidType void_type;
+  type::I32Type i32;
+  type::F32Type f32;
+
+  std::vector<std::unique_ptr<Variable>> params;
+  params.push_back(
+      std::make_unique<Variable>("var1", StorageClass::kNone, &i32));
+  params.push_back(
+      std::make_unique<Variable>("var2", StorageClass::kNone, &f32));
+
+  Function f("func", std::move(params), &void_type);
+  EXPECT_EQ(f.type_name(), "__func__void__i32__f32");
+}
+
 }  // namespace ast
 }  // namespace tint
diff --git a/src/reader/spirv/namer_test.cc b/src/reader/spirv/namer_test.cc
index 75c46c1..4f94907 100644
--- a/src/reader/spirv/namer_test.cc
+++ b/src/reader/spirv/namer_test.cc
@@ -200,7 +200,7 @@
 
 TEST_F(
     SpvNamerTest,
-    SuggestSanitizedMemberName_TakeSuggestionWhenNoConflictAfterSuggestionForLowerMember) {
+    SuggestSanitizedMemberName_TakeSuggestionWhenNoConflictAfterSuggestionForLowerMember) {  // NOLINT
   Namer namer(fail_stream_);
   EXPECT_TRUE(namer.SuggestSanitizedMemberName(1, 7, "mother"));
   EXPECT_THAT(namer.GetMemberName(1, 2), Eq(""));
diff --git a/src/reader/spirv/parser_impl.cc b/src/reader/spirv/parser_impl.cc
index 000cd64..97ce5f2 100644
--- a/src/reader/spirv/parser_impl.cc
+++ b/src/reader/spirv/parser_impl.cc
@@ -238,7 +238,7 @@
 bool ParserImpl::ParseInternalModule() {
   if (!success_) {
     return false;
-  };
+  }
   if (!RegisterExtendedInstructionImports()) {
     return false;
   }
diff --git a/src/writer/spirv/builder.cc b/src/writer/spirv/builder.cc
index 6a9063d..7d511ee 100644
--- a/src/writer/spirv/builder.cc
+++ b/src/writer/spirv/builder.cc
@@ -14,6 +14,8 @@
 
 #include "src/writer/spirv/builder.h"
 
+#include <utility>
+
 #include "spirv/unified1/spirv.h"
 #include "src/ast/struct.h"
 #include "src/ast/struct_member.h"
@@ -74,6 +76,12 @@
                 {Operand::Int(SpvAddressingModelLogical),
                  Operand::Int(SpvMemoryModelVulkanKHR)});
 
+  for (const auto& func : m.functions()) {
+    if (!GenerateFunction(func.get())) {
+      return false;
+    }
+  }
+
   for (const auto& ep : m.entry_points()) {
     if (!GenerateEntryPoint(ep.get())) {
       return false;
@@ -142,6 +150,58 @@
   return true;
 }
 
+bool Builder::GenerateFunction(ast::Function* func) {
+  uint32_t func_type_id = GenerateFunctionTypeIfNeeded(func);
+  if (func_type_id == 0) {
+    return false;
+  }
+
+  auto func_op = result_op();
+  auto func_id = func_op.to_i();
+
+  push_debug(spv::Op::OpName,
+             {Operand::Int(func_id), Operand::String(func->name())});
+
+  auto ret_id = GenerateTypeIfNeeded(func->return_type());
+  if (ret_id == 0) {
+    return false;
+  }
+
+  // TODO(dsinclair): Handle parameters
+  push_inst(spv::Op::OpFunction, {Operand::Int(ret_id), func_op,
+                                  Operand::Int(SpvFunctionControlMaskNone),
+                                  Operand::Int(func_type_id)});
+  push_inst(spv::Op::OpLabel, {result_op()});
+
+  // TODO(dsinclair): Function body ...
+
+  push_inst(spv::Op::OpFunctionEnd, {});
+
+  func_name_to_id_[func->name()] = func_id;
+  return true;
+}
+
+uint32_t Builder::GenerateFunctionTypeIfNeeded(ast::Function* func) {
+  auto val = type_name_to_id_.find(func->type_name());
+  if (val != type_name_to_id_.end()) {
+    return val->second;
+  }
+
+  auto func_op = result_op();
+  auto func_type_id = func_op.to_i();
+
+  auto ret_id = GenerateTypeIfNeeded(func->return_type());
+  if (ret_id == 0) {
+    return 0;
+  }
+
+  // TODO(dsinclair): Handle parameters
+  push_type(spv::Op::OpTypeFunction, {func_op, Operand::Int(ret_id)});
+
+  type_name_to_id_[func->type_name()] = func_type_id;
+  return func_type_id;
+}
+
 void Builder::GenerateImport(ast::Import* imp) {
   auto result = result_op();
   auto id = result.to_i();
diff --git a/src/writer/spirv/builder.h b/src/writer/spirv/builder.h
index 31efbde..fe56501 100644
--- a/src/writer/spirv/builder.h
+++ b/src/writer/spirv/builder.h
@@ -110,7 +110,7 @@
     instructions_.push_back(Instruction{op, operands});
   }
   /// @returns the instruction list
-  const std::vector<Instruction>& inst() const { return instructions_; }
+  const std::vector<Instruction>& instructions() const { return instructions_; }
   /// Adds an instruction to the annotations
   /// @param op the op to set
   /// @param operands the operands for the instruction
@@ -124,6 +124,14 @@
   /// @param ep the entry point
   /// @returns true if the instruction was generated, false otherwise
   bool GenerateEntryPoint(ast::EntryPoint* ep);
+  /// Generates the instructions for a function
+  /// @param func the function to generate
+  /// @returns true if the instructions were generated
+  bool GenerateFunction(ast::Function* func);
+  /// Generates a function type if not already created
+  /// @param func the function to generate for
+  /// @returns the ID to use for the function type. Returns 0 on failure.
+  uint32_t GenerateFunctionTypeIfNeeded(ast::Function* func);
   /// Generates an import instruction
   /// @param imp the import
   void GenerateImport(ast::Import* imp);
diff --git a/src/writer/spirv/builder_entry_point_test.cc b/src/writer/spirv/builder_entry_point_test.cc
index 953fb47..44213b4 100644
--- a/src/writer/spirv/builder_entry_point_test.cc
+++ b/src/writer/spirv/builder_entry_point_test.cc
@@ -85,7 +85,7 @@
   ASSERT_EQ(preamble.size(), 1);
   EXPECT_EQ(preamble[0].opcode(), spv::Op::OpEntryPoint);
 
-  ASSERT_TRUE(preamble[0].operands().size() >= 3);
+  ASSERT_GE(preamble[0].operands().size(), 3);
   EXPECT_EQ(preamble[0].operands()[0].to_i(), params.model);
 }
 INSTANTIATE_TEST_SUITE_P(
diff --git a/src/writer/spirv/builder_function_test.cc b/src/writer/spirv/builder_function_test.cc
new file mode 100644
index 0000000..891675d
--- /dev/null
+++ b/src/writer/spirv/builder_function_test.cc
@@ -0,0 +1,80 @@
+// Copyright 2020 The Tint Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <string>
+
+#include "gtest/gtest.h"
+#include "spirv/unified1/spirv.h"
+#include "spirv/unified1/spirv.hpp11"
+#include "src/ast/function.h"
+#include "src/ast/type/void_type.h"
+#include "src/writer/spirv/builder.h"
+#include "src/writer/spirv/spv_dump.h"
+
+namespace tint {
+namespace writer {
+namespace spirv {
+
+using BuilderTest = testing::Test;
+
+TEST_F(BuilderTest, Function_Empty) {
+  ast::type::VoidType void_type;
+  ast::Function func("a_func", {}, &void_type);
+
+  Builder b;
+  ASSERT_TRUE(b.GenerateFunction(&func));
+
+  EXPECT_EQ(DumpInstructions(b.debug()), R"(OpName %3 "a_func"
+)");
+  EXPECT_EQ(DumpInstructions(b.types()), R"(%2 = OpTypeVoid
+%1 = OpTypeFunction %2
+)");
+  EXPECT_EQ(DumpInstructions(b.instructions()), R"(%3 = OpFunction %2 None %1
+%4 = OpLabel
+OpFunctionEnd
+)");
+}
+
+TEST_F(BuilderTest, DISABLED_Function_WithParams) {}
+
+TEST_F(BuilderTest, DISABLED_Function_WithBody) {}
+
+TEST_F(BuilderTest, FunctionType) {
+  ast::type::VoidType void_type;
+  ast::Function func("a_func", {}, &void_type);
+
+  Builder b;
+  ASSERT_TRUE(b.GenerateFunction(&func));
+  EXPECT_EQ(DumpInstructions(b.types()), R"(%2 = OpTypeVoid
+%1 = OpTypeFunction %2
+)");
+}
+
+TEST_F(BuilderTest, FunctionType_DeDuplicate) {
+  ast::type::VoidType void_type;
+  ast::Function func1("a_func", {}, &void_type);
+  ast::Function func2("b_func", {}, &void_type);
+
+  Builder b;
+  ASSERT_TRUE(b.GenerateFunction(&func1));
+  ASSERT_TRUE(b.GenerateFunction(&func2));
+  EXPECT_EQ(DumpInstructions(b.types()), R"(%2 = OpTypeVoid
+%1 = OpTypeFunction %2
+)");
+}
+
+
+}  // namespace spirv
+}  // namespace writer
+}  // namespace tint
diff --git a/src/writer/spirv/spv_dump.h b/src/writer/spirv/spv_dump.h
index 34a023e..c9079c7 100644
--- a/src/writer/spirv/spv_dump.h
+++ b/src/writer/spirv/spv_dump.h
@@ -16,6 +16,7 @@
 #define SRC_WRITER_SPIRV_SPV_DUMP_H_
 
 #include <string>
+#include <vector>
 
 #include "src/writer/spirv/builder.h"
 #include "src/writer/spirv/instruction.h"