Test all CHECK-NOT in a block even if one fails

[thopre]

Summary

This commit makes FileCheck print all CHECK-NOT directive failure in a
CHECK-NOT block even if one fails. Prior to that, it would stop trying
to match CHECK-NOT directive as soon as one in the block fails.

[grimar]

Test case?

[thopre]

Add testcase

[jhenderson]

llvm/test/FileCheck/multiple-check-not-failures.txt

2 ↗

(On Diff #287245)

4–5 ↗

(On Diff #287245)

I prefer this style - it means each line clearly indicates the continuation pattern individually, whilst also showing that the entire command is present in the first line (which the existing style doesn't).

31 ↗

(On Diff #287245)

I think this line is a little too precise for a -NOT pattern - a slight change to the message would result in the check no longer doing anything useful.

You could probably just get away with something like CHECK-ERRORS-NOT: error:

[thopre]

Address review comments

llvm/test/FileCheck/multiple-check-not-failures.txt

31 ↗

(On Diff #287245)

I had to disable --dump-input for that because otherwise it shows the error again and the CHECK-NOT fails.

[jhenderson]

LGTM!

[thopre]

Rebase to see if CI is now green.

llvm/lib/Support/FileCheck.cpp

bool FileCheckString::CheckSame(const SourceMgr &SM, StringRef Buffer) const {
 
   return false;
 }
 
 bool FileCheckString::CheckNot(const SourceMgr &SM, StringRef Buffer,
                                const std::vector<const Pattern *> &NotStrings,
                                const FileCheckRequest &Req,
                                std::vector<FileCheckDiag> *Diags) const {
+  bool DirectiveFail = false;
   for (const Pattern *Pat : NotStrings) {
     assert((Pat->getCheckTy() == Check::CheckNot) && "Expect CHECK-NOT!");
 
     size_t MatchLen = 0;
     Expected<size_t> MatchResult = Pat->match(Buffer, MatchLen, SM);
 
     if (!MatchResult) {
       PrintNoMatch(false, SM, Prefix, Pat->getLoc(), *Pat, 1, Buffer,
                    Req.VerboseVerbose, Diags, MatchResult.takeError());
       continue;
     }
     size_t Pos = *MatchResult;
 
     PrintMatch(false, SM, Prefix, Pat->getLoc(), *Pat, 1, Buffer, Pos, MatchLen,
                Req, Diags);
-
-    return true;
+    DirectiveFail = true;
+    continue;
   }
 
-  return false;
+  return DirectiveFail;
 }
 
 size_t FileCheckString::CheckDag(const SourceMgr &SM, StringRef Buffer,
                                  std::vector<const Pattern *> &NotStrings,
                                  const FileCheckRequest &Req,
                                  std::vector<FileCheckDiag> *Diags) const {
   if (DagNotStrings.empty())
     return 0;