Implement data packing intrinsics

* Fix how the HLSL writer determines how to use a RWByteAddressBuffer
* Fix how the HLSL writer decides the register space for a storage
  variable
* Fix inference of hlsl format in the tint executable
* Add support for data packing intrinsics
  * type determination
  * validation
  * writers
  * spirv reader

Bug: tint:340, tint:473, tint:474
Change-Id: I45dc8fd7c6f9abc7d30f617c7e3d713d7965b76e
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/40342
Commit-Queue: Alan Baker <alanbaker@google.com>
Reviewed-by: dan sinclair <dsinclair@chromium.org>

src/semantic/intrinsic.cc

@@ -124,6 +124,16 @@ const char* str(Intrinsic i) {
       return "modf";
     case Intrinsic::kNormalize:
       return "normalize";
+    case Intrinsic::kPack4x8Snorm:
+      return "pack4x8snorm";
+    case Intrinsic::kPack4x8Unorm:
+      return "pack4x8unorm";
+    case Intrinsic::kPack2x16Snorm:
+      return "pack2x16snorm";
+    case Intrinsic::kPack2x16Unorm:
+      return "pack2x16unorm";
+    case Intrinsic::kPack2x16Float:
+      return "pack2x16float";
     case Intrinsic::kPow:
       return "pow";
     case Intrinsic::kReflect:
@@ -215,6 +225,12 @@ bool IsImageQueryIntrinsic(Intrinsic i) {
          i == Intrinsic::kTextureNumSamples;
 }
 
+bool IsDataPackingIntrinsic(Intrinsic i) {
+  return i == Intrinsic::kPack4x8Snorm || i == Intrinsic::kPack4x8Unorm ||
+         i == Intrinsic::kPack2x16Snorm || i == Intrinsic::kPack2x16Unorm ||
+         i == Intrinsic::kPack2x16Float;
+}
+
 }  // namespace intrinsic
 }  // namespace semantic
 }  // namespace tint

src/semantic/intrinsic.h

@@ -70,6 +70,11 @@ enum class Intrinsic {
   kMix,
   kModf,
   kNormalize,
+  kPack4x8Snorm,
+  kPack4x8Unorm,
+  kPack2x16Snorm,
+  kPack2x16Unorm,
+  kPack2x16Float,
   kPow,
   kReflect,
   kReverseBits,
@@ -133,6 +138,11 @@ bool IsTextureIntrinsic(Intrinsic i);
 /// @returns true if the given `i` is a image query intrinsic
 bool IsImageQueryIntrinsic(Intrinsic i);
 
+/// Determines if the given `i` is a data packing intrinsic
+/// @param i the intrinsic
+/// @returns true if the given `i` is a data packing intrinsic
+bool IsDataPackingIntrinsic(Intrinsic i);
+
 /// @returns the name of the intrinsic function. The spelling, including case,
 /// matches the name in the WGSL spec.
 const char* str(Intrinsic i);