spirv-reader: switch to HLSL-style pipeline IO

- When storing to sample_mask output, write to the 0th element
- Only make a return struct if it has members
- Adjust type signedness coercion when loading special builtins.
- Adapt tests

- Update expectations for end-to-end tests

- Handle sample_mask with stride
  Input variables normally don't have layout. But they can have it
  up through SPIR-V 1.4.
  Handle this case in the SPIR-V reader, by seeing through the
  intermediate alias type created for the strided array type.

Bug: tint:508
Change-Id: I0f19dc1305d3f250dbbc0698a602288c34245274
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/54743
Auto-Submit: David Neto <dneto@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: James Price <jrprice@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>

test/ptr_ref/load/local/i32.spvasm.expected.hlsl

@@ -1,8 +1,13 @@
-[numthreads(1, 1, 1)]
-void main() {
+void main_1() {
   int i = 0;
   i = 123;
   const int x_10 = i;
   const int x_12 = (x_10 + 1);
   return;
 }
+
+[numthreads(1, 1, 1)]
+void main() {
+  main_1();
+  return;
+}

test/ptr_ref/load/local/i32.spvasm.expected.msl

@@ -1,7 +1,7 @@
 #include <metal_stdlib>
 
 using namespace metal;
-kernel void tint_symbol() {
+void main_1() {
   int i = 0;
   i = 123;
   int const x_10 = i;
@@ -9,3 +9,8 @@ kernel void tint_symbol() {
   return;
 }
 
+kernel void tint_symbol() {
+  main_1();
+  return;
+}
+

test/ptr_ref/load/local/i32.spvasm.expected.spvasm

@@ -1,14 +1,15 @@
 ; SPIR-V
 ; Version: 1.3
 ; Generator: Google Tint Compiler; 0
-; Bound: 14
+; Bound: 17
 ; Schema: 0
                OpCapability Shader
                OpMemoryModel Logical GLSL450
                OpEntryPoint GLCompute %main "main"
                OpExecutionMode %main LocalSize 1 1 1
-               OpName %main "main"
+               OpName %main_1 "main_1"
                OpName %i "i"
+               OpName %main "main"
        %void = OpTypeVoid
           %1 = OpTypeFunction %void
         %int = OpTypeInt 32 1
@@ -17,7 +18,7 @@
           %9 = OpConstantNull %int
     %int_123 = OpConstant %int 123
       %int_1 = OpConstant %int 1
-       %main = OpFunction %void None %1
+     %main_1 = OpFunction %void None %1
           %4 = OpLabel
           %i = OpVariable %_ptr_Function_int Function %9
                OpStore %i %int_0
@@ -26,3 +27,8 @@
          %13 = OpIAdd %int %11 %int_1
                OpReturn
                OpFunctionEnd
+       %main = OpFunction %void None %1
+         %15 = OpLabel
+         %16 = OpFunctionCall %void %main_1
+               OpReturn
+               OpFunctionEnd

test/ptr_ref/load/local/i32.spvasm.expected.wgsl

@@ -1,8 +1,12 @@
-[[stage(compute)]]
-fn main() {
+fn main_1() {
   var i : i32 = 0;
   i = 123;
   let x_10 : i32 = i;
   let x_12 : i32 = (x_10 + 1);
   return;
 }
+
+[[stage(compute)]]
+fn main() {
+  main_1();
+}

test/ptr_ref/load/local/struct_field.spvasm.expected.hlsl

@@ -2,11 +2,16 @@ struct S {
   int i;
 };
 
-[numthreads(1, 1, 1)]
-void main() {
+void main_1() {
   int i = 0;
   S V = {0};
   const int x_14 = V.i;
   i = x_14;
   return;
 }
+
+[numthreads(1, 1, 1)]
+void main() {
+  main_1();
+  return;
+}

test/ptr_ref/load/local/struct_field.spvasm.expected.msl

@@ -5,7 +5,7 @@ struct S {
   int i;
 };
 
-kernel void tint_symbol() {
+void main_1() {
   int i = 0;
   S V = {};
   int const x_14 = V.i;
@@ -13,3 +13,8 @@ kernel void tint_symbol() {
   return;
 }
 
+kernel void tint_symbol() {
+  main_1();
+  return;
+}
+

test/ptr_ref/load/local/struct_field.spvasm.expected.spvasm

@@ -1,17 +1,18 @@
 ; SPIR-V
 ; Version: 1.3
 ; Generator: Google Tint Compiler; 0
-; Bound: 17
+; Bound: 20
 ; Schema: 0
                OpCapability Shader
                OpMemoryModel Logical GLSL450
                OpEntryPoint GLCompute %main "main"
                OpExecutionMode %main LocalSize 1 1 1
-               OpName %main "main"
+               OpName %main_1 "main_1"
                OpName %i "i"
                OpName %S "S"
                OpMemberName %S 0 "i"
                OpName %V "V"
+               OpName %main "main"
                OpMemberDecorate %S 0 Offset 0
        %void = OpTypeVoid
           %1 = OpTypeFunction %void
@@ -23,7 +24,7 @@
          %12 = OpConstantNull %S
        %uint = OpTypeInt 32 0
      %uint_0 = OpConstant %uint 0
-       %main = OpFunction %void None %1
+     %main_1 = OpFunction %void None %1
           %4 = OpLabel
           %i = OpVariable %_ptr_Function_int Function %8
           %V = OpVariable %_ptr_Function_S Function %12
@@ -32,3 +33,8 @@
                OpStore %i %16
                OpReturn
                OpFunctionEnd
+       %main = OpFunction %void None %1
+         %18 = OpLabel
+         %19 = OpFunctionCall %void %main_1
+               OpReturn
+               OpFunctionEnd

test/ptr_ref/load/local/struct_field.spvasm.expected.wgsl

@@ -2,11 +2,15 @@ struct S {
   i : i32;
 };
 
-[[stage(compute)]]
-fn main() {
+fn main_1() {
   var i : i32;
   var V : S;
   let x_14 : i32 = V.i;
   i = x_14;
   return;
 }
+
+[[stage(compute)]]
+fn main() {
+  main_1();
+}