[PATCH] D106577: [clang] Define __STDC_ISO_10646__

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman added reviewers: aaron.ballman, rsmith, jyknight.
aaron.ballman added a comment.

Can you also add a test that explicitly uses `-fshort-wchar` to verify that we don't predefine the macro?



================
Comment at: clang/lib/Frontend/InitPreprocessor.cpp:430-435
+  // Because Clang only supports UTF-32 or UTF-16 as the
+  // wide execution encoding, any platform that doesn't uses
+  // short wchar can represent the entire Unicode code space
+  // Unicode 13 was released in December 2020.
+  // Note that new Unicode version are *very* unlikely to affect
+  // representability
----------------
Are we going to have to remember to update this value each time Unicode updates?


================
Comment at: clang/lib/Frontend/InitPreprocessor.cpp:436-438
+  if (TI.getWCharWidth() >= 32) {
+    Builder.defineMacro("__STDC_ISO_10646__", "202012L");
+  }
----------------



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