Zhaoming Jiang 7098d3d692 tint: Add enable directive for extensions ... In this CL the enable directive is implemented. 1. Add AST node for enable directive, assign a ExtensionKind (enum) for each supported extension. 2. Use an unorder_set in ast::Module to record all required extensions' kind. 3. Provide inspector methods for getting names of used extension, and getting all used enable directives' extension names and location. 4. For different writer, the extension nodes are handled in different ways. MSL and HLSL writers will just ignore the extension nodes, while SPIRV and GLSL writers will emit corresponding code. 5. Implement unittests and end2end test for enable directive and inspector, using a reserved extension name `InternalExtensionForTesting`. Bug: tint:1472 Change-Id: I40cb4061554deb477bc2005d7e38c9718385f825 Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/86623 Kokoro: Kokoro <noreply+kokoro@google.com> Reviewed-by: Ben Clayton <bclayton@google.com> Commit-Queue: Zhaoming Jiang <zhaoming.jiang@intel.com>		2022-04-27 02:27:52 +00:00
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InternalExtensionForTesting	tint: Add enable directive for extensions	2022-04-27 02:27:52 +00:00