[llvm-rc] Fix DIALOG(EX) parsing ability. [5/8]

[mnbvmar]

Summary

This fixes a use-after-free bug that was noticed by a sanitizer buildbot (http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/7502).

[rnk]

lgtm

[zturner]

llvm/tools/llvm-rc/ResourceScriptParser.cpp

333 ↗

(On Diff #113140)

Just use if (!Control::SupportedCtrls.contains_lower(*ClassResult))

or better yet, add a function so that you can write if (!Control::isSupported(*ClassResult)) so you don't make this mistake again.

llvm/trunk/tools/llvm-rc/ResourceScriptParser.cpp

 
 Expected<Control> RCParser::parseControl() {
   // Each control definition (except CONTROL) follows one of the schemes below
   // depending on the control class:
   //  [class] text, id, x, y, width, height [, style] [, exstyle] [, helpID]
   //  [class]       id, x, y, width, height [, style] [, exstyle] [, helpID]
   // Note that control ids must be integers.
   ASSIGN_OR_RETURN(ClassResult, readIdentifier());
-  StringRef ClassUpper = ClassResult->upper();
+  std::string ClassUpper = ClassResult->upper();
   if (Control::SupportedCtls.find(ClassUpper) == Control::SupportedCtls.end())
     return getExpectedError("control type, END or '}'", true);
 
   // Read caption if necessary.
   StringRef Caption;
   if (Control::CtlsWithTitle.find(ClassUpper) != Control::CtlsWithTitle.end()) {
     ASSIGN_OR_RETURN(CaptionResult, readString());
     RETURN_IF_ERROR(consumeType(Kind::Comma));