Update spirv-reader readme
Change-Id: I933cab554b3bbd278a23b892535cba4992649002
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/48760
Auto-Submit: David Neto <dneto@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Alan Baker <alanbaker@google.com>
Commit-Queue: Alan Baker <alanbaker@google.com>
diff --git a/src/reader/spirv/README.md b/src/reader/spirv/README.md
index 9d132b0..e5f2f0d 100644
--- a/src/reader/spirv/README.md
+++ b/src/reader/spirv/README.md
@@ -13,27 +13,25 @@
# Translate SPIR-V into WGSL.
tint --format wgsl a.spv
-## Validation
+## Supported dialects
-The SPIR-V module must pass validation for the `SPV_ENV_WEBGPU_0` target
-environment in SPIRV-Tools.
+The SPIR-V module must pass validation for the Vulkan 1.1 environment in SPIRV-Tools.
+In particular, SPIR-V 1.4 and later are not supported.
-That set of rules is _experimental_ and was originally intended
-to constraint SPIR-V modules being ingested directly by the WebGPU API.
-Those rules are now too restrictive, because some amount of sanitization
-and normalization occurs during translation from SPIR-V to WGSL.
-The validation rules will be relaxed at some point TBD.
+For example, the equivalent of the following must pass:
-Generally, validation of _functionality_ used will remain, e.g. WebGPU currently
-does not support `CullDistance` or subgroup operations.
+ spirv-val --target-env vulkan1.1 a.spv
-However, detailed rules about the form of SPIR-V can be relaxed, e.g. the
-requirement to use SPIR-V 1.3, and restrictive rules about statically unreachable
-code.
+Additionally, the reader imposes additional constraints based on:
+
+* The features supported by WGSL. Some Vulkan features might not be supportable because
+ WebGPU must be portable to other graphics APIs.
+* Limitations of the reader itself. These might be relaxed in the future with extra
+ engineering work.
## Feedback
-Please file issues at https://crbug.com/tint, and put `spirv-reader` in the issue title.
+Please file issues at https://crbug.com/tint, and apply label `SpirvReader`.
-Outstanding issues can be found by using the `spirv-reader` label in the Chromium project's
-bug tracker: https://bugs.chromium.org/p/tint/issues/list?q=label:spirv-reader
+Outstanding issues can be found by using the `SpirvReader` label in the Chromium project's
+bug tracker: https://bugs.chromium.org/p/tint/issues/list?q=label:SpirvReader
