[Diagnsotics] Small Improvement on -Wmisleading-indentation

[xbolva00]

clang/lib/Parse/ParseStmt.cpp

1219–1221

DiagnosticsEngine‘s isIgnored?

[aaron.ballman]

clang/lib/Parse/ParseStmt.cpp

1219–1221

Rather than querying the diagnostics engine for each call to Check(), I think you can query this property once in the constructor and then do a simple member variable test here instead.

1229–1230

Under what circumstances is this required (can we generate a test case for it)?

[Tyker]

clang/lib/Parse/ParseStmt.cpp

1219–1221

Check() is called only once per object so there should be no difference. and DiagnosticsEngine::isIgnored requests the location of the location at which the warning is supposed to appear. this location is not know during the construction of the object.

1229–1230

i managed to reproduced it https://godbolt.org/z/XqVNPD

[aaron.ballman]

LGTM

clang/lib/Parse/ParseStmt.cpp

1219–1221

Okay, sounds good

clang/lib/Parse/ParseStmt.cpp

 enum MisleadingStatementKind { MSK_if, MSK_else, MSK_for, MSK_while };
 
 struct MisleadingIndentationChecker {
   Parser &P;
   SourceLocation StmtLoc;
   SourceLocation PrevLoc;
   unsigned NumDirectives;
   MisleadingStatementKind Kind;
-  bool NeedsChecking;
   bool ShouldSkip;
   MisleadingIndentationChecker(Parser &P, MisleadingStatementKind K,
                                SourceLocation SL)
       : P(P), StmtLoc(SL), PrevLoc(P.getCurToken().getLocation()),
         NumDirectives(P.getPreprocessor().getNumDirectives()), Kind(K),
-        NeedsChecking(true), ShouldSkip(P.getCurToken().is(tok::l_brace)) {
+        ShouldSkip(P.getCurToken().is(tok::l_brace)) {
     if (!P.MisleadingIndentationElseLoc.isInvalid()) {
       StmtLoc = P.MisleadingIndentationElseLoc;
       P.MisleadingIndentationElseLoc = SourceLocation();
     }
     if (Kind == MSK_else && !ShouldSkip)
       P.MisleadingIndentationElseLoc = SL;
   }
   void Check() {
-    NeedsChecking = false;
     Token Tok = P.getCurToken();
-    if (ShouldSkip || NumDirectives != P.getPreprocessor().getNumDirectives() ||
+    if (P.getActions().getDiagnostics().isIgnored(
+            diag::warn_misleading_indentation, Tok.getLocation()) ||
+        ShouldSkip || NumDirectives != P.getPreprocessor().getNumDirectives() ||
         Tok.isOneOf(tok::semi, tok::r_brace) || Tok.isAnnotation() ||
         Tok.getLocation().isMacroID() || PrevLoc.isMacroID() ||
         StmtLoc.isMacroID() ||
         (Kind == MSK_else && P.MisleadingIndentationElseLoc.isInvalid())) {
       P.MisleadingIndentationElseLoc = SourceLocation();
       return;
     }
+    if (Kind == MSK_else)
+      P.MisleadingIndentationElseLoc = SourceLocation();
 
     SourceManager &SM = P.getPreprocessor().getSourceManager();
     unsigned PrevColNum = SM.getSpellingColumnNumber(PrevLoc);
     unsigned CurColNum = SM.getSpellingColumnNumber(Tok.getLocation());
     unsigned StmtColNum = SM.getSpellingColumnNumber(StmtLoc);
 
     if (PrevColNum != 0 && CurColNum != 0 && StmtColNum != 0 &&
         ((PrevColNum > StmtColNum && PrevColNum == CurColNum) ||

clang/test/Parser/warn-misleading-indentation.cpp

 }
 
 void a3(int i) {
   if (1)
     {
     i = 4;
     }
     return;
-}
+}
+
+void s(int num) {
+    {
+        if (1)
+            return;
+        else
+            return;
+        return;
+    }
+    if (0)
+#ifdef WITH_WARN
+// expected-note@-2 {{here}}
+#endif
+        return;
+        return;
+#ifdef WITH_WARN
+// expected-warning@-2 {{misleading indentation; statement is not part of the previous 'if'}}
+#endif
+}