[llvm] [llvm][Tablegen][llvm-tblgen] Added keyword #undef to llvm-tblgen and fixed a small b… (PR #69135)

[zhao jiangtao via llvm-commits]

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@@ -664,7 +660,7 @@ tgtok::TokKind TGLexer::prepIsDirective() const {
           // It looks like TableGen does not support '\r' as the actual
           // carriage return, e.g. getNextChar() treats a single '\r'
           // as '\n'.  So we do the same here.
-          NextChar == '\r')
+          NextChar == '\r' || NextChar == '\0')
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whousemyname wrote:

Regarding the question I mentioned at the end of #endif, I will open a PR to explain this issue clearly.

https://github.com/llvm/llvm-project/pull/69135