Improve the calculation of location sizes for arrays and structs (revives #513)

crates/rustc_codegen_spirv/src/codegen_cx/entry.rs

@@ -535,7 +535,7 @@ impl<'tcx> CodegenCx<'tcx> {
                 Decoration::Location,
                 std::iter::once(Operand::LiteralInt32(*location)),
             );
-            *location += 1;
+            *location += self.location_size_of_type(value_spirv_type);
         }
 
         // Emit the `OpVariable` with its *Result* ID set to `var`.
@@ -554,4 +554,34 @@ impl<'tcx> CodegenCx<'tcx> {
             }
         }
     }
+
+    fn location_size_of_type(&self, ty: Word) -> u32 {
+        match self.lookup_type(ty) {
+            // Arrays take up multiple locations.
+            SpirvType::Array { count, .. } => {
+                self.builder
+                    .lookup_const_u64(count)
+                    .expect("Array type has invalid count value") as u32
+            }
+            // Structs take up per component.
+            SpirvType::Adt { field_types, .. } => {
+                let mut size = 0;
+
+                for field_type in field_types {
+                    size += self.location_size_of_type(field_type);
+                }
+
+                size
+            }
+            // 2 component vectors always take up 1 location.
+            SpirvType::Vector { count: 2, .. } => 1,
+            // 3 or 4 component vectors take up 2 locations if they have a 64-bit scalar type.
+            SpirvType::Vector { element, .. } => match self.lookup_type(element) {
+                SpirvType::Float(64) | SpirvType::Integer(64, _) => 2,
+                _ => 1,
+            },
+            SpirvType::Matrix { element, count } => count * self.location_size_of_type(element),
+            _ => 1,
+        }
+    }
 }

tests/ui/dis/array_location_calculation.rs

@@ -0,0 +1,27 @@
+// build-pass
+// compile-flags: -C llvm-args=--disassemble-globals
+
+use spirv_std::{
+    self as _,
+    glam::{DVec3, IVec4, Mat3, Vec4},
+};
+
+#[spirv(matrix)]
+pub struct Mat4x3 {
+    pub col_0: Vec4,
+    pub col_1: Vec4,
+    pub col_2: Vec4,
+}
+
+#[spirv(fragment)]
+pub fn main(
+    one: [f32; 7],
+    two: [f32; 3],
+    three: Mat3,
+    four: DVec3,
+    five: IVec4,
+    six: f32,
+    seven: Mat4x3,
+    eight: u32,
+) {
+}

tests/ui/dis/array_location_calculation.stderr

@@ -0,0 +1,82 @@
+OpCapability Float64
+OpCapability Int16
+OpCapability Int64
+OpCapability Int8
+OpCapability ShaderClockKHR
+OpCapability Shader
+OpExtension "SPV_KHR_shader_clock"
+OpMemoryModel Logical Simple
+OpEntryPoint Fragment %1 "main" %2 %3 %4 %5 %6 %7 %8 %9
+OpExecutionMode %1 OriginUpperLeft
+%10 = OpString "$OPSTRING_FILENAME/array_location_calculation.rs"
+OpMemberName %11 0 "x_axis"
+OpMemberName %11 1 "y_axis"
+OpMemberName %11 2 "z_axis"
+OpName %11 "spirv_std::glam::core::storage::Columns3<spirv_std::glam::XYZ<f32>>"
+OpMemberName %12 0 "0"
+OpName %12 "spirv_std::glam::Mat3"
+OpName %13 "array_location_calculation::main"
+OpName %2 "one"
+OpName %3 "two"
+OpName %4 "three"
+OpName %5 "four"
+OpName %6 "five"
+OpName %7 "six"
+OpName %8 "seven"
+OpName %9 "eight"
+OpMemberName %11 0 "x_axis"
+OpMemberName %11 1 "y_axis"
+OpMemberName %11 2 "z_axis"
+OpMemberName %12 0 "0"
+OpMemberName %12 0 "0"
+OpMemberName %11 0 "x_axis"
+OpMemberName %11 1 "y_axis"
+OpMemberName %11 2 "z_axis"
+OpDecorate %14 ArrayStride 4
+OpDecorate %15 ArrayStride 4
+OpMemberDecorate %11 0 Offset 0
+OpMemberDecorate %11 1 Offset 16
+OpMemberDecorate %11 2 Offset 32
+OpMemberDecorate %12 0 Offset 0
+OpDecorate %2 Location 0
+OpDecorate %3 Location 7
+OpDecorate %4 Location 10
+OpDecorate %5 Location 13
+OpDecorate %6 Location 15
+OpDecorate %7 Location 16
+OpDecorate %8 Location 17
+OpDecorate %9 Location 20
+%16 = OpTypeVoid
+%17 = OpTypeFloat 32
+%18 = OpTypeInt 32 0
+%19 = OpConstant  %18  7
+%14 = OpTypeArray %17 %19
+%20 = OpConstant  %18  3
+%15 = OpTypeArray %17 %20
+%21 = OpTypeVector %17 3
+%11 = OpTypeStruct %21 %21 %21
+%12 = OpTypeStruct %11
+%22 = OpTypeFloat 64
+%23 = OpTypeVector %22 3
+%24 = OpTypeInt 32 1
+%25 = OpTypeVector %24 4
+%26 = OpTypeVector %17 4
+%27 = OpTypeMatrix %26 3
+%28 = OpTypeFunction %16 %14 %15 %12 %23 %25 %17 %27 %18
+%29 = OpTypeFunction %16
+%30 = OpTypePointer Input %14
+%2 = OpVariable  %30  Input
+%31 = OpTypePointer Input %15
+%3 = OpVariable  %31  Input
+%32 = OpTypePointer Input %12
+%4 = OpVariable  %32  Input
+%33 = OpTypePointer Input %23
+%5 = OpVariable  %33  Input
+%34 = OpTypePointer Input %25
+%6 = OpVariable  %34  Input
+%35 = OpTypePointer Input %17
+%7 = OpVariable  %35  Input
+%36 = OpTypePointer Input %27
+%8 = OpVariable  %36  Input
+%37 = OpTypePointer Input %18
+%9 = OpVariable  %37  Input