[analyzer] Fix an assertation failure for invalid sourcelocation, add a new debug checker

For a rather short code snippet, if debug.ReportStmts (added in this patch) was
enabled, a bug reporter visitor crashed:

struct h {
  operator int();
};

int k() {
  return h();
}

Ultimately, this originated from PathDiagnosticLocation::createMemberLoc, as it
didn't handle the case where it's MemberExpr typed parameter returned and
invalid SourceLocation for MemberExpr::getMemberLoc. The solution was to find
any related valid SourceLocaion, and Stmt::getBeginLoc happens to be just that.

Differential Revision: https://reviews.llvm.org/D58777

llvm-svn: 356161

1 files changed, 11 insertions, 1 deletions

diff --git a/clang/lib/StaticAnalyzer/Core/PathDiagnostic.cpp b/clang/lib/StaticAnalyzer/Core/PathDiagnostic.cpp
index 13e3bcfad2a..cc1e7e1798f 100644
--- a/clang/lib/StaticAnalyzer/Core/PathDiagnostic.cpp
+++ b/clang/lib/StaticAnalyzer/Core/PathDiagnostic.cpp
@@ -571,6 +571,8 @@ static SourceLocation getValidSourceLocation(const Stmt* S,
     } while (!L.isValid());
   }
 
+  // FIXME: Ironically, this assert actually fails in some cases.
+  //assert(L.isValid());
   return L;
 }
 
@@ -671,7 +673,15 @@ PathDiagnosticLocation::createConditionalColonLoc(
 PathDiagnosticLocation
 PathDiagnosticLocation::createMemberLoc(const MemberExpr *ME,
                                         const SourceManager &SM) {
-  return PathDiagnosticLocation(ME->getMemberLoc(), SM, SingleLocK);
+
+  assert(ME->getMemberLoc().isValid() || ME->getBeginLoc().isValid());
+
+  // In some cases, getMemberLoc isn't valid -- in this case we'll return with
+  // some other related valid SourceLocation.
+  if (ME->getMemberLoc().isValid())
+    return PathDiagnosticLocation(ME->getMemberLoc(), SM, SingleLocK);
+
+  return PathDiagnosticLocation(ME->getBeginLoc(), SM, SingleLocK);
 }
 
 PathDiagnosticLocation