Collapse #[repr(transparent)] types

crates/rustc_codegen_spirv/src/abi.rs

@@ -3,7 +3,7 @@
 
 use crate::attr::{AggregatedSpirvAttributes, IntrinsicType};
 use crate::codegen_cx::CodegenCx;
-use crate::spirv_type::SpirvType;
+use crate::spirv_type::{SpirvType, name_type_id};
 use itertools::Itertools;
 use rspirv::spirv::{Dim, ImageFormat, StorageClass, Word};
 use rustc_abi::ExternAbi as Abi;
@@ -321,6 +321,33 @@ impl<'tcx> ConvSpirvType<'tcx> for FnAbi<'tcx, Ty<'tcx>> {
     }
 }
 
+/// If `layout` has exactly one non-ZST field positioned at offset 0 with size and
+/// alignment matching the outer layout, returns that field.
+///
+/// This captures the structural shape of a "newtype wrapper" — a single meaningful
+/// field padded out to the outer type, which can be substituted for the outer type
+/// in a SPIR-V type graph as long as the caller has *independently* verified that
+/// the ABIs match (either via `BackendRepr::eq_up_to_validity`, or via
+/// `#[repr(transparent)]`, which guarantees full ABI identity by construction).
+fn sole_structural_newtype_field<'tcx>(
+    cx: &CodegenCx<'tcx>,
+    layout: TyAndLayout<'tcx>,
+) -> Option<TyAndLayout<'tcx>> {
+    let mut non_zst = (0..layout.fields.count()).filter(|&i| !layout.field(cx, i).is_zst());
+    let i = non_zst.next()?;
+    if non_zst.next().is_some() {
+        return None;
+    }
+    let field = layout.field(cx, i);
+    // Only unpack a newtype if the field and the newtype line up
+    // perfectly, in every way that could potentially affect ABI.
+    (layout.fields.offset(i) == Size::ZERO
+        && field.size == layout.size
+        && field.align.abi == layout.align.abi
+        && field.backend_repr.eq_up_to_validity(&layout.backend_repr))
+    .then_some(field)
+}
+
 impl<'tcx> ConvSpirvType<'tcx> for TyAndLayout<'tcx> {
     fn spirv_type(&self, mut span: Span, cx: &CodegenCx<'tcx>) -> Word {
         if let TyKind::Adt(adt, args) = *self.ty.kind() {
@@ -379,23 +406,8 @@ impl<'tcx> ConvSpirvType<'tcx> for TyAndLayout<'tcx> {
                 //      a new one, offering the `(a, b)` shape `rustc_codegen_ssa`
                 //      expects, while letting noop pointercasts access the sole
                 //      `BackendRepr::ScalarPair` field - this is the approach taken here
-                let mut non_zst_fields = (0..self.fields.count())
-                    .map(|i| (i, self.field(cx, i)))
-                    .filter(|(_, field)| !field.is_zst());
-                let sole_non_zst_field = match (non_zst_fields.next(), non_zst_fields.next()) {
-                    (Some(field), None) => Some(field),
-                    _ => None,
-                };
-                if let Some((i, field)) = sole_non_zst_field {
-                    // Only unpack a newtype if the field and the newtype line up
-                    // perfectly, in every way that could potentially affect ABI.
-                    if self.fields.offset(i) == Size::ZERO
-                        && field.size == self.size
-                        && field.align.abi == self.align.abi
-                        && field.backend_repr.eq_up_to_validity(&self.backend_repr)
-                    {
-                        return field.spirv_type(span, cx);
-                    }
+                if let Some(field) = sole_structural_newtype_field(cx, *self) {
+                    return field.spirv_type(span, cx);
                 }
 
                 // Note: We can't use auto_struct_layout here because the spirv types here might be undefined due to
@@ -447,7 +459,24 @@ impl<'tcx> ConvSpirvType<'tcx> for TyAndLayout<'tcx> {
                 .tcx
                 .dcx()
                 .fatal("scalable vectors are not supported in SPIR-V backend"),
-            BackendRepr::Memory { sized: _ } => trans_aggregate(cx, span, *self),
+            BackendRepr::Memory { sized: _ } => {
+                // For `#[repr(transparent)]` newtypes, reuse the single non-ZST
+                // field's SPIR-V type directly instead of wrapping it in an
+                // `OpTypeStruct`, if the type is `#[repr(transparent)]`.
+                // Otherwise, we're manipulating the abi too much and the
+                // format args decompiler fails.
+                if let TyKind::Adt(adt, _) = self.ty.kind()
+                    && adt.repr().transparent()
+                    && let Some(field) = sole_structural_newtype_field(cx, *self)
+                {
+                    let inner_id = field.spirv_type(span, cx);
+                    // Preserve the wrapper's name as an `OpName` alias on the
+                    // inner SPIR-V type so disassembly still shows it.
+                    name_type_id(cx, inner_id, TyLayoutNameKey::from(*self));
+                    return inner_id;
+                }
+                trans_aggregate(cx, span, *self)
+            }
         }
     }
 }

crates/rustc_codegen_spirv/src/spirv_type.rs

@@ -92,6 +92,17 @@ pub enum SpirvType<'tcx> {
     RayQueryKhr,
 }
 
+/// Emit an `OpName` for a type `id`, deduplicated per `(id, name_key)` pair.
+/// Unlike [`SpirvType::def_with_name`], this operates on an existing `id` - useful
+/// for types reused across multiple Rust types (e.g. `#[repr(transparent)]`
+/// newtype collapse, where the wrapper's name is attached to the inner's id).
+pub fn name_type_id<'tcx>(cx: &CodegenCx<'tcx>, id: Word, name_key: TyLayoutNameKey<'tcx>) {
+    let mut type_names = cx.type_cache.type_names.borrow_mut();
+    if type_names.entry(id).or_default().insert(name_key) {
+        cx.emit_global().name(id, name_key.to_string());
+    }
+}
+
 impl SpirvType<'_> {
     /// Note: `Builder::type_*` should be called *nowhere else* but here, to ensure
     /// `CodegenCx::type_defs` stays up-to-date
@@ -266,13 +277,7 @@ impl SpirvType<'_> {
         name_key: TyLayoutNameKey<'tcx>,
     ) -> Word {
         let id = self.def(def_span, cx);
-
-        // Only emit `OpName` if this is the first time we see this name.
-        let mut type_names = cx.type_cache.type_names.borrow_mut();
-        if type_names.entry(id).or_default().insert(name_key) {
-            cx.emit_global().name(id, name_key.to_string());
-        }
-
+        name_type_id(cx, id, name_key);
         id
     }
 

tests/compiletests/README.md

@@ -79,7 +79,7 @@ contents of `path/to/test.rs.stderr`.
     * `// normalize-stderr-test "OpCapability VulkanMemoryModel\n" -> ""` remove the vulkan memory model *capability*, only used by `vulkan` targets
     * `// normalize-stderr-test "OpExtension .SPV_KHR_vulkan_memory_model.\n" -> ""` remove the vulkan memory model *extension*, only used by `vulkan` targets
     * `// normalize-stderr-test "OpMemoryModel Logical Vulkan" -> "OpMemoryModel Logical Simple"` replace the `Vulkan` memory model with `Simple`, which `spv` targets use
-    * `// normalize-stderr-test "; .*\n" -> ""` remove comments on spirv version by rspirv
+    * `// normalize-stderr-test "^(; .*\n)*" -> ""` remove comments on spirv version by rspirv
   * remove rustc error src paths:
     * `// normalize-stderr-test "\S*/lib/rustlib/" -> "$$SYSROOT/lib/rustlib/"` normalize path to crates delivered with rustc, such as `core`
     * `// normalize-stderr-test "\S*/crates/spirv-std/src/" -> "$$SPIRV_STD_SRC/"` normalize path to the `spirv-std` crate

tests/compiletests/ui/dis/spec_constant_array.rs

@@ -9,7 +9,7 @@
 // ignore-vulkan1.1
 
 // compile-flags: -C llvm-args=--disassemble
-// normalize-stderr-test "; .*\n" -> ""
+// normalize-stderr-test "^(; .*\n)*" -> ""
 // normalize-stderr-test "OpCapability VulkanMemoryModel\n" -> ""
 // normalize-stderr-test "OpSource .*\n" -> ""
 // normalize-stderr-test "OpMemoryModel Logical Vulkan" -> "OpMemoryModel Logical Simple"

tests/compiletests/ui/dis/spec_constant_array.stderr

@@ -3,6 +3,7 @@ OpMemoryModel Logical Simple
 OpEntryPoint GLCompute %1 "main" %2
 OpExecutionMode %1 LocalSize 1 1 1
 %3 = OpString "$DIR/spec_constant_array.rs"
+OpName %2 "out"
 OpDecorate %4 Block
 OpMemberDecorate %4 0 Offset 0
 OpDecorate %2 Binding 0

tests/compiletests/ui/entry/asm/entry1_global_asm.rs

@@ -3,7 +3,7 @@
 // normalize-stderr-test "OpSource .*\n" -> ""
 // normalize-stderr-test "OpLine .*\n" -> ""
 // normalize-stderr-test "%\d+ = OpString .*\n" -> ""
-// normalize-stderr-test "; .*\n" -> ""
+// normalize-stderr-test "^(; .*\n)*" -> ""
 // normalize-stderr-test "OpCapability VulkanMemoryModel\n" -> ""
 // normalize-stderr-test "OpMemoryModel Logical Vulkan" -> "OpMemoryModel Logical Simple"
 // ignore-spv1.0

tests/compiletests/ui/entry/asm/entry1_reference.rs

@@ -3,7 +3,7 @@
 // normalize-stderr-test "OpSource .*\n" -> ""
 // normalize-stderr-test "OpLine .*\n" -> ""
 // normalize-stderr-test "%\d+ = OpString .*\n" -> ""
-// normalize-stderr-test "; .*\n" -> ""
+// normalize-stderr-test "^(; .*\n)*" -> ""
 // normalize-stderr-test "OpCapability VulkanMemoryModel\n" -> ""
 // normalize-stderr-test "OpMemoryModel Logical Vulkan" -> "OpMemoryModel Logical Simple"
 // ignore-spv1.0

tests/compiletests/ui/entry/asm/entry2_global_asm.rs

@@ -3,7 +3,7 @@
 // normalize-stderr-test "OpSource .*\n" -> ""
 // normalize-stderr-test "OpLine .*\n" -> ""
 // normalize-stderr-test "%\d+ = OpString .*\n" -> ""
-// normalize-stderr-test "; .*\n" -> ""
+// normalize-stderr-test "^(; .*\n)*" -> ""
 // normalize-stderr-test "OpCapability VulkanMemoryModel\n" -> ""
 // normalize-stderr-test "OpMemoryModel Logical Vulkan" -> "OpMemoryModel Logical Simple"
 // ignore-spv1.0

tests/compiletests/ui/entry/asm/entry2_reference.rs

@@ -3,7 +3,7 @@
 // normalize-stderr-test "OpSource .*\n" -> ""
 // normalize-stderr-test "OpLine .*\n" -> ""
 // normalize-stderr-test "%\d+ = OpString .*\n" -> ""
-// normalize-stderr-test "; .*\n" -> ""
+// normalize-stderr-test "^(; .*\n)*" -> ""
 // normalize-stderr-test "OpCapability VulkanMemoryModel\n" -> ""
 // normalize-stderr-test "OpMemoryModel Logical Vulkan" -> "OpMemoryModel Logical Simple"
 // ignore-spv1.0

tests/compiletests/ui/entry/asm/entry3_generic_asm.rs

@@ -3,7 +3,7 @@
 // normalize-stderr-test "OpSource .*\n" -> ""
 // normalize-stderr-test "OpLine .*\n" -> ""
 // normalize-stderr-test "%\d+ = OpString .*\n" -> ""
-// normalize-stderr-test "; .*\n" -> ""
+// normalize-stderr-test "^(; .*\n)*" -> ""
 // normalize-stderr-test "OpCapability VulkanMemoryModel\n" -> ""
 // normalize-stderr-test "OpMemoryModel Logical Vulkan" -> "OpMemoryModel Logical Simple"
 // ignore-spv1.0

tests/compiletests/ui/entry/asm/entry3_global_asm.rs

@@ -3,7 +3,7 @@
 // normalize-stderr-test "OpSource .*\n" -> ""
 // normalize-stderr-test "OpLine .*\n" -> ""
 // normalize-stderr-test "%\d+ = OpString .*\n" -> ""
-// normalize-stderr-test "; .*\n" -> ""
+// normalize-stderr-test "^(; .*\n)*" -> ""
 // normalize-stderr-test "OpCapability VulkanMemoryModel\n" -> ""
 // normalize-stderr-test "OpMemoryModel Logical Vulkan" -> "OpMemoryModel Logical Simple"
 // ignore-spv1.0

tests/compiletests/ui/entry/asm/entry3_reference.rs

@@ -3,7 +3,7 @@
 // normalize-stderr-test "OpSource .*\n" -> ""
 // normalize-stderr-test "OpLine .*\n" -> ""
 // normalize-stderr-test "%\d+ = OpString .*\n" -> ""
-// normalize-stderr-test "; .*\n" -> ""
+// normalize-stderr-test "^(; .*\n)*" -> ""
 // normalize-stderr-test "OpCapability VulkanMemoryModel\n" -> ""
 // normalize-stderr-test "OpMemoryModel Logical Vulkan" -> "OpMemoryModel Logical Simple"
 // ignore-spv1.0

tests/compiletests/ui/entry/asm/entry_fragment_global_asm.rs

@@ -3,7 +3,7 @@
 // normalize-stderr-test "OpSource .*\n" -> ""
 // normalize-stderr-test "OpLine .*\n" -> ""
 // normalize-stderr-test "%\d+ = OpString .*\n" -> ""
-// normalize-stderr-test "; .*\n" -> ""
+// normalize-stderr-test "^(; .*\n)*" -> ""
 // normalize-stderr-test "OpCapability VulkanMemoryModel\n" -> ""
 // normalize-stderr-test "OpMemoryModel Logical Vulkan" -> "OpMemoryModel Logical Simple"
 // ignore-spv1.0

tests/compiletests/ui/entry/asm/entry_fragment_reference.rs

@@ -3,7 +3,7 @@
 // normalize-stderr-test "OpSource .*\n" -> ""
 // normalize-stderr-test "OpLine .*\n" -> ""
 // normalize-stderr-test "%\d+ = OpString .*\n" -> ""
-// normalize-stderr-test "; .*\n" -> ""
+// normalize-stderr-test "^(; .*\n)*" -> ""
 // normalize-stderr-test "OpCapability VulkanMemoryModel\n" -> ""
 // normalize-stderr-test "OpMemoryModel Logical Vulkan" -> "OpMemoryModel Logical Simple"
 // ignore-spv1.0

tests/compiletests/ui/glam/offsets_vec3_vec3a.rs

@@ -3,7 +3,7 @@
 // normalize-stderr-test "OpSource .*\n" -> ""
 // normalize-stderr-test "OpLine .*\n" -> ""
 // normalize-stderr-test "%\d+ = OpString .*\n" -> ""
-// normalize-stderr-test "; .*\n" -> ""
+// normalize-stderr-test "^(; .*\n)*" -> ""
 // normalize-stderr-test "OpCapability VulkanMemoryModel\n" -> ""
 // normalize-stderr-test "OpMemoryModel Logical Vulkan" -> "OpMemoryModel Logical Simple"
 // ignore-vulkan1.0

tests/compiletests/ui/image/write_comp.rs

@@ -4,7 +4,7 @@
 // normalize-stderr-test "OpSource .*\n" -> ""
 // normalize-stderr-test "OpLine .*\n" -> ""
 // normalize-stderr-test "%\d+ = OpString .*\n" -> ""
-// normalize-stderr-test "; .*\n" -> ""
+// normalize-stderr-test "^(; .*\n)*" -> ""
 // normalize-stderr-test "OpCapability VulkanMemoryModel\n" -> ""
 // normalize-stderr-test "OpMemoryModel Logical Vulkan" -> "OpMemoryModel Logical Simple"
 // ignore-vulkan1.0

tests/compiletests/ui/image/write_comp_format.rs

@@ -4,7 +4,7 @@
 // normalize-stderr-test "OpSource .*\n" -> ""
 // normalize-stderr-test "OpLine .*\n" -> ""
 // normalize-stderr-test "%\d+ = OpString .*\n" -> ""
-// normalize-stderr-test "; .*\n" -> ""
+// normalize-stderr-test "^(; .*\n)*" -> ""
 // normalize-stderr-test "OpCapability VulkanMemoryModel\n" -> ""
 // normalize-stderr-test "OpMemoryModel Logical Vulkan" -> "OpMemoryModel Logical Simple"
 // ignore-vulkan1.0

tests/compiletests/ui/lang/abi/transparent.rs

@@ -0,0 +1,91 @@
+// build-pass
+// compile-flags: -C llvm-args=--disassemble
+// normalize-stderr-test "OpSource .*\n" -> ""
+// normalize-stderr-test "OpLine .*\n" -> ""
+// normalize-stderr-test "%\d+ = OpString .*\n" -> ""
+// normalize-stderr-test "^(; .*\n)*" -> ""
+// normalize-stderr-test "OpCapability VulkanMemoryModel\n" -> ""
+// normalize-stderr-test "OpMemoryModel Logical Vulkan" -> "OpMemoryModel Logical Simple"
+// ignore-spv1.0
+// ignore-spv1.1
+// ignore-spv1.2
+// ignore-spv1.3
+// ignore-vulkan1.0
+// ignore-vulkan1.1
+
+use core::marker::PhantomData;
+use spirv_std::glam::*;
+use spirv_std::spirv;
+
+#[repr(C)]
+#[derive(Default)]
+struct SomeStruct {
+    a: u32,
+    b: f32,
+    c: Vec3,
+}
+
+#[derive(Default)]
+pub struct A(u32);
+#[repr(transparent)]
+#[derive(Default)]
+pub struct ATrans(u32);
+
+#[derive(Default)]
+pub struct B(Vec3);
+#[repr(transparent)]
+#[derive(Default)]
+pub struct BTrans(Vec3);
+
+#[derive(Default)]
+pub struct C(SomeStruct);
+#[repr(transparent)]
+#[derive(Default)]
+pub struct CTrans(SomeStruct);
+
+#[derive(Default)]
+pub struct D<'a>(u32, PhantomData<&'a ()>);
+#[repr(transparent)]
+#[derive(Default)]
+pub struct DTrans<'a>(u32, PhantomData<&'a ()>);
+
+#[derive(Default)]
+pub struct E(ATrans);
+#[repr(transparent)]
+#[derive(Default)]
+pub struct ETrans(ATrans);
+
+#[derive(Default)]
+pub struct Zst;
+#[repr(transparent)]
+#[derive(Default)]
+pub struct ZstTrans;
+
+#[spirv(vertex)]
+pub fn main(
+    a: &mut A,
+    a_trans: &mut ATrans,
+    b: &mut B,
+    b_trans: &mut BTrans,
+    c: &mut C,
+    c_trans: &mut CTrans,
+    d: &mut D<'static>,
+    d_trans: &mut DTrans<'static>,
+    e: &mut E,
+    e_trans: &mut ETrans,
+    zst: &mut Zst,
+    zst_trans: &mut ZstTrans,
+) {
+    *a = Default::default();
+    *a_trans = Default::default();
+    *b = Default::default();
+    *b_trans = Default::default();
+    *c = Default::default();
+    *c_trans = Default::default();
+    *d = Default::default();
+    *d_trans = Default::default();
+    *e = Default::default();
+    *e_trans = Default::default();
+    *zst = Default::default();
+    *zst_trans = Default::default();
+}