[FileCheck]: Fix diagnostics for NOT prefixes (#78412)

Fixes #70221 

Fix a bug in FileCheck that corrects the error message when multiple
prefixes are provided
through --check-prefixes and one of them is a PREFIX-NOT.

Earlier, only the first of the provided prefixes was displayed as the
erroneous prefix, while the
actual error might be on the prefix that occurred at the end of the
prefix list in the input file.

Now, the right NOT prefix is shown in the error message.

1 files changed, 33 insertions, 28 deletions

diff --git a/llvm/lib/FileCheck/FileCheck.cpp b/llvm/lib/FileCheck/FileCheck.cpp
index b728c14..0d5bdf7 100644
--- a/llvm/lib/FileCheck/FileCheck.cpp
+++ b/llvm/lib/FileCheck/FileCheck.cpp
@@ -1784,7 +1784,7 @@ bool FileCheck::readCheckFile(
 
   PatternContext->createLineVariable();
 
-  std::vector<Pattern> ImplicitNegativeChecks;
+  std::vector<FileCheckString::DagNotPrefixInfo> ImplicitNegativeChecks;
   for (StringRef PatternString : Req.ImplicitCheckNot) {
     // Create a buffer with fake command line content in order to display the
     // command line option responsible for the specific implicit CHECK-NOT.
@@ -1807,14 +1807,15 @@ bool FileCheck::readCheckFile(
       }
     }
 
-    ImplicitNegativeChecks.push_back(
-        Pattern(Check::CheckNot, PatternContext.get()));
-    ImplicitNegativeChecks.back().parsePattern(PatternInBuffer,
-                                               "IMPLICIT-CHECK", SM, Req);
+    ImplicitNegativeChecks.emplace_back(
+        Pattern(Check::CheckNot, PatternContext.get()),
+        StringRef("IMPLICIT-CHECK"));
+    ImplicitNegativeChecks.back().DagNotPat.parsePattern(
+        PatternInBuffer, "IMPLICIT-CHECK", SM, Req);
   }
 
-  std::vector<Pattern> DagNotMatches = ImplicitNegativeChecks;
-
+  std::vector<FileCheckString::DagNotPrefixInfo> DagNotMatches =
+      ImplicitNegativeChecks;
   // LineNumber keeps track of the line on which CheckPrefix instances are
   // found.
   unsigned LineNumber = 1;
@@ -1926,7 +1927,7 @@ bool FileCheck::readCheckFile(
 
     // Handle CHECK-DAG/-NOT.
     if (CheckTy == Check::CheckDAG || CheckTy == Check::CheckNot) {
-      DagNotMatches.push_back(P);
+      DagNotMatches.emplace_back(P, UsedPrefix);
       continue;
     }
 
@@ -2165,7 +2166,7 @@ size_t FileCheckString::Check(const SourceMgr &SM, StringRef Buffer,
                               FileCheckRequest &Req,
                               std::vector<FileCheckDiag> *Diags) const {
   size_t LastPos = 0;
-  std::vector<const Pattern *> NotStrings;
+  std::vector<const DagNotPrefixInfo *> NotStrings;
 
   // IsLabelScanMode is true when we are scanning forward to find CHECK-LABEL
   // bounds; we have not processed variable definitions within the bounded block
@@ -2302,17 +2303,19 @@ 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 FileCheckString::CheckNot(
+    const SourceMgr &SM, StringRef Buffer,
+    const std::vector<const DagNotPrefixInfo *> &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!");
-    Pattern::MatchResult MatchResult = Pat->match(Buffer, SM);
-    if (Error Err = reportMatchResult(/*ExpectedMatch=*/false, SM, Prefix,
-                                      Pat->getLoc(), *Pat, 1, Buffer,
-                                      std::move(MatchResult), Req, Diags)) {
+  for (auto NotInfo : NotStrings) {
+    assert((NotInfo->DagNotPat.getCheckTy() == Check::CheckNot) &&
+           "Expect CHECK-NOT!");
+    Pattern::MatchResult MatchResult = NotInfo->DagNotPat.match(Buffer, SM);
+    if (Error Err = reportMatchResult(
+            /*ExpectedMatch=*/false, SM, NotInfo->DagNotPrefix,
+            NotInfo->DagNotPat.getLoc(), NotInfo->DagNotPat, 1, Buffer,
+            std::move(MatchResult), Req, Diags)) {
       cantFail(handleErrors(std::move(Err), [&](const ErrorReported &E) {}));
       DirectiveFail = true;
       continue;
@@ -2321,10 +2324,11 @@ bool FileCheckString::CheckNot(const SourceMgr &SM, StringRef Buffer,
   return DirectiveFail;
 }
 
-size_t FileCheckString::CheckDag(const SourceMgr &SM, StringRef Buffer,
-                                 std::vector<const Pattern *> &NotStrings,
-                                 const FileCheckRequest &Req,
-                                 std::vector<FileCheckDiag> *Diags) const {
+size_t
+FileCheckString::CheckDag(const SourceMgr &SM, StringRef Buffer,
+                          std::vector<const DagNotPrefixInfo *> &NotStrings,
+                          const FileCheckRequest &Req,
+                          std::vector<FileCheckDiag> *Diags) const {
   if (DagNotStrings.empty())
     return 0;
 
@@ -2344,13 +2348,14 @@ size_t FileCheckString::CheckDag(const SourceMgr &SM, StringRef Buffer,
   // group, so we don't use a range-based for loop here.
   for (auto PatItr = DagNotStrings.begin(), PatEnd = DagNotStrings.end();
        PatItr != PatEnd; ++PatItr) {
-    const Pattern &Pat = *PatItr;
+    const Pattern &Pat = PatItr->DagNotPat;
+    const StringRef DNPrefix = PatItr->DagNotPrefix;
     assert((Pat.getCheckTy() == Check::CheckDAG ||
             Pat.getCheckTy() == Check::CheckNot) &&
            "Invalid CHECK-DAG or CHECK-NOT!");
 
     if (Pat.getCheckTy() == Check::CheckNot) {
-      NotStrings.push_back(&Pat);
+      NotStrings.push_back(&*PatItr);
       continue;
     }
 
@@ -2367,7 +2372,7 @@ size_t FileCheckString::CheckDag(const SourceMgr &SM, StringRef Buffer,
       // With a group of CHECK-DAGs, a single mismatching means the match on
       // that group of CHECK-DAGs fails immediately.
       if (MatchResult.TheError || Req.VerboseVerbose) {
-        if (Error Err = reportMatchResult(/*ExpectedMatch=*/true, SM, Prefix,
+        if (Error Err = reportMatchResult(/*ExpectedMatch=*/true, SM, DNPrefix,
                                           Pat.getLoc(), Pat, 1, MatchBuffer,
                                           std::move(MatchResult), Req, Diags)) {
           cantFail(
@@ -2430,13 +2435,13 @@ size_t FileCheckString::CheckDag(const SourceMgr &SM, StringRef Buffer,
     }
     if (!Req.VerboseVerbose)
       cantFail(printMatch(
-          /*ExpectedMatch=*/true, SM, Prefix, Pat.getLoc(), Pat, 1, Buffer,
+          /*ExpectedMatch=*/true, SM, DNPrefix, Pat.getLoc(), Pat, 1, Buffer,
           Pattern::MatchResult(MatchPos, MatchLen, Error::success()), Req,
           Diags));
 
     // Handle the end of a CHECK-DAG group.
     if (std::next(PatItr) == PatEnd ||
-        std::next(PatItr)->getCheckTy() == Check::CheckNot) {
+        std::next(PatItr)->DagNotPat.getCheckTy() == Check::CheckNot) {
       if (!NotStrings.empty()) {
         // If there are CHECK-NOTs between two CHECK-DAGs or from CHECK to
         // CHECK-DAG, verify that there are no 'not' strings occurred in that