tint: Implement `f16` keyword in Tint frontend
This patch:
1. Add the `f16` WGSL extension.
2. Add `f16` as keyword, and remove it from reserved word list.
3. Add ast::f16 and sem::f16, and implement validation that using `f16`
type must be with `f16` extension enabled.
4. Add `Number<NumberKindF16>` for f16 literal and constant, and add
`ast::FloatLiteralExpression::Suffix::kH`.
5. Add placeholder in all writer which report error when try to emit f16
type.
Bugs: tint:1473, tint:1502
Change-Id: Ifb363beeb2699ed7cac57e07227d1b2cfa8050b4
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/89922
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Zhaoming Jiang <zhaoming.jiang@intel.com>
diff --git a/src/tint/resolver/resolver.cc b/src/tint/resolver/resolver.cc
index 962dd02..38a5025 100644
--- a/src/tint/resolver/resolver.cc
+++ b/src/tint/resolver/resolver.cc
@@ -172,6 +172,14 @@
[&](const ast::Bool*) { return builder_->create<sem::Bool>(); },
[&](const ast::I32*) { return builder_->create<sem::I32>(); },
[&](const ast::U32*) { return builder_->create<sem::U32>(); },
+ [&](const ast::F16* t) -> sem::F16* {
+ // Validate if f16 type is allowed.
+ if (builder_->AST().Extensions().count(ast::Enable::ExtensionKind::kF16) == 0) {
+ AddError("f16 used without 'f16' extension enabled", t->source);
+ return nullptr;
+ }
+ return builder_->create<sem::F16>();
+ },
[&](const ast::F32*) { return builder_->create<sem::F32>(); },
[&](const ast::Vector* t) -> sem::Vector* {
if (!t->type) {
