[analyzer] Overhaul how the static analyzer expects CFGs by forcing CFGs to be linearized only when used by the static analyzer. This required a rewrite of LiveVariables, and exposed a ton of subtle bugs.

The motivation of this large change is to drastically simplify the logic in ExprEngine going forward.

Some fallout is that the output of some BugReporterVisitors is not as accurate as before; those will
need to be fixed over time.  There is also some possible performance regression as RemoveDeadBindings
will be called frequently; this can also be improved over time.

llvm-svn: 136419

1 files changed, 12 insertions, 6 deletions

diff --git a/clang/lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp
index b540bce9817..69081a93a63 100644
--- a/clang/lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp
@@ -111,13 +111,19 @@ void UnreachableCodeChecker::checkEndAnalysis(ExplodedGraph &G,
     // FIXME: This should be extended to include other unreachable markers,
     // such as llvm_unreachable.
     if (!CB->empty()) {
-      CFGElement First = CB->front();
-      if (const CFGStmt *S = First.getAs<CFGStmt>()) {
-        if (const CallExpr *CE = dyn_cast<CallExpr>(S->getStmt())) {
-          if (CE->isBuiltinCall(Ctx) == Builtin::BI__builtin_unreachable)
-            continue;
-        }
+      bool foundUnreachable = false;
+      for (CFGBlock::const_iterator ci = CB->begin(), ce = CB->end();
+           ci != ce; ++ci) {
+        if (const CFGStmt *S = (*ci).getAs<CFGStmt>())
+          if (const CallExpr *CE = dyn_cast<CallExpr>(S->getStmt())) {
+            if (CE->isBuiltinCall(Ctx) == Builtin::BI__builtin_unreachable) {
+              foundUnreachable = true;
+              break;
+            }
+          }
       }
+      if (foundUnreachable)
+        continue;
     }
 
     // We found a block that wasn't covered - find the statement to report