diff --git a/src/back/glsl/mod.rs b/src/back/glsl/mod.rs
index a8c41faf85..ddb1c6c6c0 100644
--- a/src/back/glsl/mod.rs
+++ b/src/back/glsl/mod.rs
@@ -1686,18 +1686,23 @@ fn glsl_scalar(kind: ScalarKind, width: crate::Bytes) -> Result<ScalarString<'st
 /// Helper function that returns the glsl variable name for a builtin
 fn glsl_built_in(built_in: BuiltIn) -> &'static str {
     match built_in {
+        // vertex
         BuiltIn::Position => "gl_Position",
-        BuiltIn::GlobalInvocationId => "gl_GlobalInvocationID",
         BuiltIn::BaseInstance => "gl_BaseInstance",
         BuiltIn::BaseVertex => "gl_BaseVertex",
         BuiltIn::ClipDistance => "gl_ClipDistance",
         BuiltIn::InstanceIndex => "gl_InstanceID",
-        BuiltIn::VertexIndex => "gl_VertexID",
         BuiltIn::PointSize => "gl_PointSize",
+        BuiltIn::VertexIndex => "gl_VertexID",
+        // fragment
         BuiltIn::FragCoord => "gl_FragCoord",
+        BuiltIn::FragDepth => "gl_FragDepth",
         BuiltIn::FrontFacing => "gl_FrontFacing",
         BuiltIn::SampleIndex => "gl_SampleID",
-        BuiltIn::FragDepth => "gl_FragDepth",
+        BuiltIn::SampleMaskIn => "gl_SampleMaskIn",
+        BuiltIn::SampleMaskOut => "gl_SampleMask",
+        // compute
+        BuiltIn::GlobalInvocationId => "gl_GlobalInvocationID",
         BuiltIn::LocalInvocationId => "gl_LocalInvocationID",
         BuiltIn::LocalInvocationIndex => "gl_LocalInvocationIndex",
         BuiltIn::WorkGroupId => "gl_WorkGroupID",
diff --git a/src/back/msl/mod.rs b/src/back/msl/mod.rs
index 053704303f..53c8ddf38c 100644
--- a/src/back/msl/mod.rs
+++ b/src/back/msl/mod.rs
@@ -173,6 +173,8 @@ impl ResolvedBinding {
                     Bi::FragDepth => "depth(any)",
                     Bi::FrontFacing => "front_facing",
                     Bi::SampleIndex => "sample_id",
+                    Bi::SampleMaskIn => "sample_mask",
+                    Bi::SampleMaskOut => "sample_mask",
                     // compute
                     Bi::GlobalInvocationId => "thread_position_in_grid",
                     Bi::LocalInvocationId => "thread_position_in_threadgroup",
diff --git a/src/back/spv/writer.rs b/src/back/spv/writer.rs
index bd4fbac0e3..8f9d3ef93a 100644
--- a/src/back/spv/writer.rs
+++ b/src/back/spv/writer.rs
@@ -856,23 +856,28 @@ impl Writer {
                     ));
             }
             Some(crate::Binding::BuiltIn(built_in)) => {
+                use crate::BuiltIn as Bi;
                 let built_in = match built_in {
-                    crate::BuiltIn::BaseInstance => spirv::BuiltIn::BaseInstance,
-                    crate::BuiltIn::BaseVertex => spirv::BuiltIn::BaseVertex,
-                    crate::BuiltIn::ClipDistance => spirv::BuiltIn::ClipDistance,
-                    crate::BuiltIn::InstanceIndex => spirv::BuiltIn::InstanceIndex,
-                    crate::BuiltIn::Position => spirv::BuiltIn::Position,
-                    crate::BuiltIn::VertexIndex => spirv::BuiltIn::VertexIndex,
-                    crate::BuiltIn::PointSize => spirv::BuiltIn::PointSize,
-                    crate::BuiltIn::FragCoord => spirv::BuiltIn::FragCoord,
-                    crate::BuiltIn::FrontFacing => spirv::BuiltIn::FrontFacing,
-                    crate::BuiltIn::SampleIndex => spirv::BuiltIn::SampleId,
-                    crate::BuiltIn::FragDepth => spirv::BuiltIn::FragDepth,
-                    crate::BuiltIn::GlobalInvocationId => spirv::BuiltIn::GlobalInvocationId,
-                    crate::BuiltIn::LocalInvocationId => spirv::BuiltIn::LocalInvocationId,
-                    crate::BuiltIn::LocalInvocationIndex => spirv::BuiltIn::LocalInvocationIndex,
-                    crate::BuiltIn::WorkGroupId => spirv::BuiltIn::WorkgroupId,
-                    crate::BuiltIn::WorkGroupSize => spirv::BuiltIn::WorkgroupSize,
+                    Bi::BaseInstance => spirv::BuiltIn::BaseInstance,
+                    Bi::BaseVertex => spirv::BuiltIn::BaseVertex,
+                    Bi::ClipDistance => spirv::BuiltIn::ClipDistance,
+                    Bi::InstanceIndex => spirv::BuiltIn::InstanceIndex,
+                    Bi::PointSize => spirv::BuiltIn::PointSize,
+                    Bi::Position => spirv::BuiltIn::Position,
+                    Bi::VertexIndex => spirv::BuiltIn::VertexIndex,
+                    // fragment
+                    Bi::FragCoord => spirv::BuiltIn::FragCoord,
+                    Bi::FragDepth => spirv::BuiltIn::FragDepth,
+                    Bi::FrontFacing => spirv::BuiltIn::FrontFacing,
+                    Bi::SampleIndex => spirv::BuiltIn::SampleId,
+                    Bi::SampleMaskIn => spirv::BuiltIn::SampleMask,
+                    Bi::SampleMaskOut => spirv::BuiltIn::SampleMask,
+                    // compute
+                    Bi::GlobalInvocationId => spirv::BuiltIn::GlobalInvocationId,
+                    Bi::LocalInvocationId => spirv::BuiltIn::LocalInvocationId,
+                    Bi::LocalInvocationIndex => spirv::BuiltIn::LocalInvocationIndex,
+                    Bi::WorkGroupId => spirv::BuiltIn::WorkgroupId,
+                    Bi::WorkGroupSize => spirv::BuiltIn::WorkgroupSize,
                 };
 
                 self.annotations
diff --git a/src/front/spv/convert.rs b/src/front/spv/convert.rs
index 167863efa3..e2259aa4e4 100644
--- a/src/front/spv/convert.rs
+++ b/src/front/spv/convert.rs
@@ -98,21 +98,28 @@ pub fn map_width(word: spirv::Word) -> Result<crate::Bytes, Error> {
         .map_err(|_| Error::InvalidTypeWidth(word))
 }
 
-pub fn map_builtin(word: spirv::Word) -> Result<crate::BuiltIn, Error> {
+pub fn map_builtin(word: spirv::Word, is_output: bool) -> Result<crate::BuiltIn, Error> {
     use spirv::BuiltIn as Bi;
     Ok(match spirv::BuiltIn::from_u32(word) {
         Some(Bi::BaseInstance) => crate::BuiltIn::BaseInstance,
         Some(Bi::BaseVertex) => crate::BuiltIn::BaseVertex,
         Some(Bi::ClipDistance) => crate::BuiltIn::ClipDistance,
         Some(Bi::InstanceIndex) => crate::BuiltIn::InstanceIndex,
+        Some(Bi::PointSize) => crate::BuiltIn::PointSize,
         Some(Bi::Position) => crate::BuiltIn::Position,
         Some(Bi::VertexIndex) => crate::BuiltIn::VertexIndex,
         // fragment
-        Some(Bi::PointSize) => crate::BuiltIn::PointSize,
         Some(Bi::FragCoord) => crate::BuiltIn::FragCoord,
+        Some(Bi::FragDepth) => crate::BuiltIn::FragDepth,
         Some(Bi::FrontFacing) => crate::BuiltIn::FrontFacing,
         Some(Bi::SampleId) => crate::BuiltIn::SampleIndex,
-        Some(Bi::FragDepth) => crate::BuiltIn::FragDepth,
+        Some(Bi::SampleMask) => {
+            if is_output {
+                crate::BuiltIn::SampleMaskOut
+            } else {
+                crate::BuiltIn::SampleMaskIn
+            }
+        }
         // compute
         Some(Bi::GlobalInvocationId) => crate::BuiltIn::GlobalInvocationId,
         Some(Bi::LocalInvocationId) => crate::BuiltIn::LocalInvocationId,
diff --git a/src/front/spv/mod.rs b/src/front/spv/mod.rs
index d69b431d0c..fc07e58b4e 100644
--- a/src/front/spv/mod.rs
+++ b/src/front/spv/mod.rs
@@ -158,7 +158,7 @@ bitflags::bitflags! {
 #[derive(Debug, Default)]
 struct Decoration {
     name: Option<String>,
-    built_in: Option<crate::BuiltIn>,
+    built_in: Option<spirv::Word>,
     location: Option<spirv::Word>,
     desc_set: Option<spirv::Word>,
     desc_index: Option<spirv::Word>,
@@ -177,7 +177,7 @@ impl Decoration {
         }
     }
 
-    fn get_binding(&self) -> Option<crate::Binding> {
+    fn get_binding(&self, is_output: bool) -> Option<crate::Binding> {
         //TODO: validate this better
         match *self {
             Decoration {
@@ -186,7 +186,13 @@ impl Decoration {
                 desc_set: None,
                 desc_index: None,
                 ..
-            } => Some(crate::Binding::BuiltIn(built_in)),
+            } => match convert::map_builtin(built_in, is_output) {
+                Ok(built_in) => Some(crate::Binding::BuiltIn(built_in)),
+                Err(e) => {
+                    log::warn!("{:?}", e);
+                    None
+                }
+            },
             Decoration {
                 built_in: None,
                 location: Some(loc),
@@ -381,11 +387,7 @@ impl<I: Iterator<Item = u32>> Parser<I> {
         match dec_typed {
             spirv::Decoration::BuiltIn => {
                 inst.expect(base_words + 2)?;
-                let raw = self.next()?;
-                match map_builtin(raw) {
-                    Ok(built_in) => dec.built_in = Some(built_in),
-                    Err(_e) => log::warn!("Unsupported builtin {}", raw),
-                };
+                dec.built_in = Some(self.next()?);
             }
             spirv::Decoration::Location => {
                 inst.expect(base_words + 2)?;
@@ -2345,7 +2347,7 @@ impl<I: Iterator<Item = u32>> Parser<I> {
             crate::StorageAccess::empty()
         };
 
-        let binding = dec.get_binding();
+        let binding = dec.get_binding(class == crate::StorageClass::Output);
         let ty = match binding {
             // SPIR-V only cares about some of the built-in types being integer.
             // Naga requires them to be strictly unsigned, so we have to patch it.
diff --git a/src/front/wgsl/conv.rs b/src/front/wgsl/conv.rs
index d10a3afcd0..8aa0d52383 100644
--- a/src/front/wgsl/conv.rs
+++ b/src/front/wgsl/conv.rs
@@ -21,6 +21,9 @@ pub fn map_built_in(word: &str) -> Result<crate::BuiltIn, Error<'_>> {
         "front_facing" => crate::BuiltIn::FrontFacing,
         "frag_coord" => crate::BuiltIn::FragCoord,
         "frag_depth" => crate::BuiltIn::FragDepth,
+        "sample_index" => crate::BuiltIn::SampleIndex,
+        "sample_mask_in" => crate::BuiltIn::SampleMaskIn,
+        "sample_mask_out" => crate::BuiltIn::SampleMaskOut,
         // compute
         "global_invocation_id" => crate::BuiltIn::GlobalInvocationId,
         "local_invocation_id" => crate::BuiltIn::LocalInvocationId,
diff --git a/src/lib.rs b/src/lib.rs
index 2719c40ccb..b002ac82d5 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -140,14 +140,16 @@ pub enum BuiltIn {
     BaseVertex,
     ClipDistance,
     InstanceIndex,
+    PointSize,
     Position,
     VertexIndex,
     // fragment
-    PointSize,
     FragCoord,
+    FragDepth,
     FrontFacing,
     SampleIndex,
-    FragDepth,
+    SampleMaskIn,
+    SampleMaskOut,
     // compute
     GlobalInvocationId,
     LocalInvocationId,
diff --git a/src/proc/validator.rs b/src/proc/validator.rs
index 14de47ff76..619f1f349a 100644
--- a/src/proc/validator.rs
+++ b/src/proc/validator.rs
@@ -158,6 +158,8 @@ impl crate::GlobalVariable {
                     | Bi::InstanceIndex
                     | Bi::VertexIndex
                     | Bi::SampleIndex
+                    | Bi::SampleMaskIn
+                    | Bi::SampleMaskOut
                     | Bi::LocalInvocationIndex => Ti::Scalar {
                         kind: Sk::Uint,
                         width,
@@ -500,10 +502,10 @@ impl Validator {
                             | (crate::ShaderStage::Vertex, crate::BuiltIn::BaseVertex)
                             | (crate::ShaderStage::Vertex, crate::BuiltIn::InstanceIndex)
                             | (crate::ShaderStage::Vertex, crate::BuiltIn::VertexIndex)
-                            | (crate::ShaderStage::Fragment, crate::BuiltIn::PointSize)
                             | (crate::ShaderStage::Fragment, crate::BuiltIn::FragCoord)
                             | (crate::ShaderStage::Fragment, crate::BuiltIn::FrontFacing)
                             | (crate::ShaderStage::Fragment, crate::BuiltIn::SampleIndex)
+                            | (crate::ShaderStage::Fragment, crate::BuiltIn::SampleMaskIn)
                             | (crate::ShaderStage::Compute, crate::BuiltIn::GlobalInvocationId)
                             | (crate::ShaderStage::Compute, crate::BuiltIn::LocalInvocationId)
                             | (crate::ShaderStage::Compute, crate::BuiltIn::LocalInvocationIndex)
@@ -527,7 +529,8 @@ impl Validator {
                             (crate::ShaderStage::Vertex, crate::BuiltIn::Position)
                             | (crate::ShaderStage::Vertex, crate::BuiltIn::PointSize)
                             | (crate::ShaderStage::Vertex, crate::BuiltIn::ClipDistance)
-                            | (crate::ShaderStage::Fragment, crate::BuiltIn::FragDepth) => (),
+                            | (crate::ShaderStage::Fragment, crate::BuiltIn::FragDepth)
+                            | (crate::ShaderStage::Fragment, crate::BuiltIn::SampleMaskOut) => (),
                             _ => return Err(EntryPointError::InvalidBuiltIn(built_in)),
                         },
                         Some(crate::Binding::Location(loc)) => {