[llvm-debuginfo-analyzer] Return by reference instead of value - Warning analysis data.

[CarlosAlbertoEnciso]

Summary

The following functions are used in the unittest, to access
information about invalid information detected by the Reader
during the debug information analysis:

• getDebugTags
• getWarningOffsets
• getInvalidLocations
• getInvalidCoverages
• getInvalidRanges
• getLinesZero

Just return a reference to the container with the information.

Note: Issue discovered by the smart pointers changes to the tool.
https://reviews.llvm.org/D137933

[dblaikie]

Sounds good (this sort of cleanup is fine for post-commit review, FWIW)

[CarlosAlbertoEnciso]

In D138092#3931440, @dblaikie wrote:

Sounds good (this sort of cleanup is fine for post-commit review, FWIW)

Thanks for all your help in the reviews.

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

public:
   void addInvalidCoverage(LVSymbol *Symbol);
   // Record symbols with invalid locations.
   void addInvalidLocation(LVLocation *Location);
   // Record scopes with invalid ranges.
   void addInvalidRange(LVLocation *Location);
   // Record line zero.
   void addLineZero(LVLine *Line);
 
-  const LVTagOffsetsMap getDebugTags() const { return DebugTags; }
-  const LVOffsetElementMap getWarningOffsets() const { return WarningOffsets; }
-  const LVOffsetLocationsMap getInvalidLocations() const {
+  const LVTagOffsetsMap &getDebugTags() const { return DebugTags; }
+  const LVOffsetElementMap &getWarningOffsets() const { return WarningOffsets; }
+  const LVOffsetLocationsMap &getInvalidLocations() const {
     return InvalidLocations;
   }
-  const LVOffsetSymbolMap getInvalidCoverages() const {
+  const LVOffsetSymbolMap &getInvalidCoverages() const {
     return InvalidCoverages;
   }
-  const LVOffsetLocationsMap getInvalidRanges() const { return InvalidRanges; }
-  const LVOffsetLinesMap getLinesZero() const { return LinesZero; }
+  const LVOffsetLocationsMap &getInvalidRanges() const { return InvalidRanges; }
+  const LVOffsetLinesMap &getLinesZero() const { return LinesZero; }
 
   // Process ranges, locations and calculate coverage.
   void processRangeLocationCoverage(
       LVValidLocation ValidLocation = &LVLocation::validateRanges);
 
   // Add matched element.
   void addMatched(LVElement *Element) { MatchedElements.push_back(Element); }
   void addMatched(LVScope *Scope) { MatchedScopes.push_back(Scope); }