[analyzer] Do not run visitors until the fixpoint, run only once.

In the current implementation, we run visitors until the fixed point is
reached.
That is, if a visitor adds another visitor, the currently processed path
is destroyed, all diagnostics is discarded, and it is regenerated again,
until it's no longer modified.
This pattern has a few negative implications:

 - This loop does not even guarantee to terminate.
   E.g. just imagine two visitors bouncing a diagnostics around.
 - Performance-wise, e.g. for sqlite3 all visitors are being re-run at
   least 10 times for some bugs.
   We have already seen a few reports where it leads to timeouts.
 - If we want to add more computationally intense visitors, this will
   become worse.
 - From architectural standpoint, the current layout requires copying
   visitors, which is conceptually wrong, and can be annoying (e.g. no
   unique_ptr on visitors allowed).

The proposed change is a much simpler architecture: the outer loop
processes nodes upwards, and whenever the visitor is added it only
processes current nodes and above, thus guaranteeing termination.

Differential Revision: https://reviews.llvm.org/D47856

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@335666 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 1 insertions, 2 deletions

diff --git a/lib/StaticAnalyzer/Checkers/LocalizationChecker.cpp b/lib/StaticAnalyzer/Checkers/LocalizationChecker.cpp
index bfdb511e74..849b1193c0 100644
--- a/lib/StaticAnalyzer/Checkers/LocalizationChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/LocalizationChecker.cpp
@@ -113,8 +113,7 @@ NonLocalizedStringChecker::NonLocalizedStringChecker() {
 }
 
 namespace {
-class NonLocalizedStringBRVisitor final
-    : public BugReporterVisitorImpl<NonLocalizedStringBRVisitor> {
+class NonLocalizedStringBRVisitor final : public BugReporterVisitor {
 
   const MemRegion *NonLocalizedString;
   bool Satisfied;