[llvm-debuginfo-analyzer] (05/09) - Select elements - Test case (UndefinedBehaviorSanitizer)

[CarlosAlbertoEnciso]

Summary

The test case 'checkFlexiblePatterns' caused a failure in:

https://lab.llvm.org/buildbot/#/builders/85/builds/11590
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior

runtime error: applying zero offset to null pointer
llvm/lib/Support/regengine.inc:151:18

The logical view is traversed and for each logical element a
series of match criterias are applied. One of those criterias
is to match its name or type name to a given pattern.

If the logical element does not have a type (for instance a
'namespace') do not try to use its type name, which is a
empty string as the 'matcher' function receives a null pointer.

[probinson]

LGTM

[CarlosAlbertoEnciso]

@probinson Thanks for your valuable review.

llvm/include/llvm/DebugInfo/LogicalView/Core/LVOptions.h

class LVPatterns final {
   }
 
   void addElement(LVElement *Element);
 
   template <typename T, typename U>
   void resolveGenericPatternMatch(T *Element, const U &Requests) {
     assert(Element && "Element must not be nullptr");
     auto CheckPattern = [=]() -> bool {
-      return Element->isNamed() &&
-             (matchGenericPattern(Element->getName()) ||
+      return (Element->isNamed() && matchGenericPattern(Element->getName())) ||
+             (Element->isTyped() &&
               matchGenericPattern(Element->getTypeName()));
     };
     auto CheckOffset = [=]() -> bool {
       return matchOffsetPattern(Element->getOffset());
     };
     if ((options().getSelectGenericPattern() && CheckPattern()) ||
         (options().getSelectOffsetPattern() && CheckOffset()) ||
         ((Requests.size() || ElementRequest.size()) &&

llvm/lib/DebugInfo/LogicalView/Core/LVOptions.cpp

if (options().getSelectExecute() && !options().getReportExecute()) {
     options().setReportExecute();
     options().setReportList();
   }
 }
 
 // Match a general pattern.
 bool LVPatterns::matchPattern(StringRef Input, const LVMatchInfo &MatchInfo) {
   bool Matched = false;
+  // Do not match an empty 'Input'.
+  if (Input.empty())
+    return Matched;
   // Traverse all match specifications.
   for (const LVMatch &Match : MatchInfo) {
     switch (Match.Mode) {
     case LVMatchMode::Match:
       Matched = Input.equals(Match.Pattern);
       break;
     case LVMatchMode::NoCase:
       Matched = Input.equals_insensitive(Match.Pattern);