diff --git a/src/dawn_native/d3d12/RenderPipelineD3D12.cpp b/src/dawn_native/d3d12/RenderPipelineD3D12.cpp
index 0978bd8..12aa05b 100644
--- a/src/dawn_native/d3d12/RenderPipelineD3D12.cpp
+++ b/src/dawn_native/d3d12/RenderPipelineD3D12.cpp
@@ -319,11 +319,11 @@
         Device* device,
         const RenderPipelineDescriptor* descriptor) {
         Ref<RenderPipeline> pipeline = AcquireRef(new RenderPipeline(device, descriptor));
-        DAWN_TRY(pipeline->Initialize(descriptor));
+        DAWN_TRY(pipeline->Initialize());
         return pipeline;
     }
 
-    MaybeError RenderPipeline::Initialize(const RenderPipelineDescriptor* descriptor) {
+    MaybeError RenderPipeline::Initialize() {
         Device* device = ToBackend(GetDevice());
         uint32_t compileFlags = 0;
 
@@ -340,13 +340,16 @@
 
         D3D12_GRAPHICS_PIPELINE_STATE_DESC descriptorD3D12 = {};
 
+        const ProgrammableStage& vertexStage = GetStage(SingleShaderStage::Vertex);
+        const ProgrammableStage& fragmentStage = GetStage(SingleShaderStage::Fragment);
+
         PerStage<const char*> entryPoints;
-        entryPoints[SingleShaderStage::Vertex] = descriptor->vertex.entryPoint;
-        entryPoints[SingleShaderStage::Fragment] = descriptor->fragment->entryPoint;
+        entryPoints[SingleShaderStage::Vertex] = vertexStage.entryPoint.c_str();
+        entryPoints[SingleShaderStage::Fragment] = fragmentStage.entryPoint.c_str();
 
         PerStage<ShaderModule*> modules;
-        modules[SingleShaderStage::Vertex] = ToBackend(descriptor->vertex.module);
-        modules[SingleShaderStage::Fragment] = ToBackend(descriptor->fragment->module);
+        modules[SingleShaderStage::Vertex] = ToBackend(vertexStage.module.Get());
+        modules[SingleShaderStage::Fragment] = ToBackend(fragmentStage.module.Get());
 
         PerStage<D3D12_SHADER_BYTECODE*> shaders;
         shaders[SingleShaderStage::Vertex] = &descriptorD3D12.VS;
diff --git a/src/dawn_native/d3d12/RenderPipelineD3D12.h b/src/dawn_native/d3d12/RenderPipelineD3D12.h
index 67222f4..ed71da9 100644
--- a/src/dawn_native/d3d12/RenderPipelineD3D12.h
+++ b/src/dawn_native/d3d12/RenderPipelineD3D12.h
@@ -42,7 +42,7 @@
       private:
         ~RenderPipeline() override;
         using RenderPipelineBase::RenderPipelineBase;
-        MaybeError Initialize(const RenderPipelineDescriptor* descriptor);
+        MaybeError Initialize();
         D3D12_INPUT_LAYOUT_DESC ComputeInputLayout(
             std::array<D3D12_INPUT_ELEMENT_DESC, kMaxVertexAttributes>* inputElementDescriptors);
 
diff --git a/src/dawn_native/metal/RenderPipelineMTL.h b/src/dawn_native/metal/RenderPipelineMTL.h
index 43eebec..07a2d77 100644
--- a/src/dawn_native/metal/RenderPipelineMTL.h
+++ b/src/dawn_native/metal/RenderPipelineMTL.h
@@ -47,7 +47,7 @@
 
       private:
         using RenderPipelineBase::RenderPipelineBase;
-        MaybeError Initialize(const RenderPipelineDescriptor* descriptor);
+        MaybeError Initialize();
 
         MTLVertexDescriptor* MakeVertexDesc();
 
diff --git a/src/dawn_native/metal/RenderPipelineMTL.mm b/src/dawn_native/metal/RenderPipelineMTL.mm
index 17706d7..a38a23a 100644
--- a/src/dawn_native/metal/RenderPipelineMTL.mm
+++ b/src/dawn_native/metal/RenderPipelineMTL.mm
@@ -314,11 +314,11 @@
         Device* device,
         const RenderPipelineDescriptor* descriptor) {
         Ref<RenderPipeline> pipeline = AcquireRef(new RenderPipeline(device, descriptor));
-        DAWN_TRY(pipeline->Initialize(descriptor));
+        DAWN_TRY(pipeline->Initialize());
         return pipeline;
     }
 
-    MaybeError RenderPipeline::Initialize(const RenderPipelineDescriptor* descriptor) {
+    MaybeError RenderPipeline::Initialize() {
         mMtlPrimitiveTopology = MTLPrimitiveTopology(GetPrimitiveTopology());
         mMtlFrontFace = MTLFrontFace(GetFrontFace());
         mMtlCullMode = ToMTLCullMode(GetCullMode());
@@ -338,8 +338,9 @@
         }
         descriptorMTL.vertexDescriptor = vertexDesc.Get();
 
-        ShaderModule* vertexModule = ToBackend(descriptor->vertex.module);
-        const char* vertexEntryPoint = descriptor->vertex.entryPoint;
+        const ProgrammableStage& vertexStage = GetStage(SingleShaderStage::Vertex);
+        ShaderModule* vertexModule = ToBackend(vertexStage.module.Get());
+        const char* vertexEntryPoint = vertexStage.entryPoint.c_str();
         ShaderModule::MetalFunctionData vertexData;
         DAWN_TRY(vertexModule->CreateFunction(vertexEntryPoint, SingleShaderStage::Vertex,
                                               ToBackend(GetLayout()), &vertexData, 0xFFFFFFFF,
@@ -350,8 +351,9 @@
             mStagesRequiringStorageBufferLength |= wgpu::ShaderStage::Vertex;
         }
 
-        ShaderModule* fragmentModule = ToBackend(descriptor->fragment->module);
-        const char* fragmentEntryPoint = descriptor->fragment->entryPoint;
+        const ProgrammableStage& fragmentStage = GetStage(SingleShaderStage::Fragment);
+        ShaderModule* fragmentModule = ToBackend(fragmentStage.module.Get());
+        const char* fragmentEntryPoint = fragmentStage.entryPoint.c_str();
         ShaderModule::MetalFunctionData fragmentData;
         DAWN_TRY(fragmentModule->CreateFunction(fragmentEntryPoint, SingleShaderStage::Fragment,
                                                 ToBackend(GetLayout()), &fragmentData,
diff --git a/src/dawn_native/vulkan/RenderPipelineVk.cpp b/src/dawn_native/vulkan/RenderPipelineVk.cpp
index 22bfe82..5fb4266 100644
--- a/src/dawn_native/vulkan/RenderPipelineVk.cpp
+++ b/src/dawn_native/vulkan/RenderPipelineVk.cpp
@@ -323,38 +323,40 @@
         Device* device,
         const RenderPipelineDescriptor* descriptor) {
         Ref<RenderPipeline> pipeline = AcquireRef(new RenderPipeline(device, descriptor));
-        DAWN_TRY(pipeline->Initialize(descriptor));
+        DAWN_TRY(pipeline->Initialize());
         return pipeline;
     }
 
-    MaybeError RenderPipeline::Initialize(const RenderPipelineDescriptor* descriptor) {
+    MaybeError RenderPipeline::Initialize() {
         Device* device = ToBackend(GetDevice());
 
         VkPipelineShaderStageCreateInfo shaderStages[2];
         {
             // Generate a new VkShaderModule with BindingRemapper tint transform for each
             // pipeline
+            const ProgrammableStage& vertexStage = GetStage(SingleShaderStage::Vertex);
             DAWN_TRY_ASSIGN(shaderStages[0].module,
-                            ToBackend(descriptor->vertex.module)
-                                ->GetTransformedModuleHandle(descriptor->vertex.entryPoint,
+                            ToBackend(vertexStage.module.Get())
+                                ->GetTransformedModuleHandle(vertexStage.entryPoint.c_str(),
                                                              ToBackend(GetLayout())));
+            const ProgrammableStage& fragmentStage = GetStage(SingleShaderStage::Fragment);
             DAWN_TRY_ASSIGN(shaderStages[1].module,
-                            ToBackend(descriptor->fragment->module)
-                                ->GetTransformedModuleHandle(descriptor->fragment->entryPoint,
+                            ToBackend(fragmentStage.module.Get())
+                                ->GetTransformedModuleHandle(fragmentStage.entryPoint.c_str(),
                                                              ToBackend(GetLayout())));
             shaderStages[0].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO;
             shaderStages[0].pNext = nullptr;
             shaderStages[0].flags = 0;
             shaderStages[0].stage = VK_SHADER_STAGE_VERTEX_BIT;
             shaderStages[0].pSpecializationInfo = nullptr;
-            shaderStages[0].pName = descriptor->vertex.entryPoint;
+            shaderStages[0].pName = vertexStage.entryPoint.c_str();
 
             shaderStages[1].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO;
             shaderStages[1].pNext = nullptr;
             shaderStages[1].flags = 0;
             shaderStages[1].stage = VK_SHADER_STAGE_FRAGMENT_BIT;
             shaderStages[1].pSpecializationInfo = nullptr;
-            shaderStages[1].pName = descriptor->fragment->entryPoint;
+            shaderStages[1].pName = fragmentStage.entryPoint.c_str();
         }
 
         PipelineVertexInputStateCreateInfoTemporaryAllocations tempAllocations;
diff --git a/src/dawn_native/vulkan/RenderPipelineVk.h b/src/dawn_native/vulkan/RenderPipelineVk.h
index 9339bb6..fe653c8 100644
--- a/src/dawn_native/vulkan/RenderPipelineVk.h
+++ b/src/dawn_native/vulkan/RenderPipelineVk.h
@@ -38,7 +38,7 @@
       private:
         ~RenderPipeline() override;
         using RenderPipelineBase::RenderPipelineBase;
-        MaybeError Initialize(const RenderPipelineDescriptor* descriptor);
+        MaybeError Initialize();
 
         struct PipelineVertexInputStateCreateInfoTemporaryAllocations {
             std::array<VkVertexInputBindingDescription, kMaxVertexBuffers> bindings;