[clang] [clang-format] Support of TableGen basic format restrictions. (PR #81611)

[Hirofumi Nakamura via cfe-commits]

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@@ -5072,7 +5072,38 @@ bool TokenAnnotator::spaceRequiredBefore(const AnnotatedLine &Line,
          Left.endsSequence(tok::greatergreater, tok::l_brace))) {
       return false;
     }
+  } else if (Style.isTableGen()) {
+    // Avoid to connect [ and {. [{ is start token of multiline string.
+    if (Left.is(tok::l_square) && Right.is(tok::l_brace))
+      return true;
+    if (Left.is(tok::r_brace) && Right.is(tok::r_square))
+      return true;
+    // Do not insert around colon in DAGArg and cond operator.
+    if (Right.is(TT_TableGenDAGArgListColon) ||
+        Left.is(TT_TableGenDAGArgListColon)) {
+      return false;
+    }
+    if (Right.is(TT_TableGenCondOperatorColon))
+      return false;
+    // Do not insert bang operators and consequent openers.
+    if (Right.isOneOf(tok::l_paren, tok::less) &&
+        Left.isOneOf(TT_TableGenBangOperator, TT_TableGenCondOperator)) {
+      return false;
+    }
+    // Trailing paste requires space before '{' or ':', the case in name values.
+    // Not before ';', the case in normal values.
+    if (Left.is(TT_TableGenTrailingPasteOperator) &&
+        Right.isOneOf(tok::l_brace, tok::colon)) {
+      return true;
+    }
+    // Otherwise paste operator does not prefer space around.
+    if (Left.is(tok::hash) || Right.is(tok::hash))
+      return false;
+    // Sure not to connect after defining keywords.
+    if (Keywords.isTableGenDefinition(Left))
+      return true;
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hnakamura5 wrote:

Returning true forces to insert space between Left and Right tokens.

https://github.com/llvm/llvm-project/pull/81611