[CFG] [analyzer] Disable argument construction contexts for variadic functions.

The analyzer doesn't make use of them anyway and they seem to have
pretty weird AST from time to time, so let's just skip them for now.

Fixes a crash reported as pr37769.

Differential Revision: https://reviews.llvm.org/D50855

llvm-svn: 340977

1 files changed, 21 insertions, 9 deletions

diff --git a/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp b/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
index 9634157a70f..04190deb7a8 100644
--- a/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
+++ b/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
@@ -283,11 +283,10 @@ ProgramStateRef ExprEngine::getInitialState(const LocationContext *InitLoc) {
   return state;
 }
 
-ProgramStateRef
-ExprEngine::createTemporaryRegionIfNeeded(ProgramStateRef State,
-                                          const LocationContext *LC,
-                                          const Expr *InitWithAdjustments,
-                                          const Expr *Result) {
+ProgramStateRef ExprEngine::createTemporaryRegionIfNeeded(
+    ProgramStateRef State, const LocationContext *LC,
+    const Expr *InitWithAdjustments, const Expr *Result,
+    const SubRegion **OutRegionWithAdjustments) {
   // FIXME: This function is a hack that works around the quirky AST
   // we're often having with respect to C++ temporaries. If only we modelled
   // the actual execution order of statements properly in the CFG,
@@ -297,8 +296,11 @@ ExprEngine::createTemporaryRegionIfNeeded(ProgramStateRef State,
   if (!Result) {
     // If we don't have an explicit result expression, we're in "if needed"
     // mode. Only create a region if the current value is a NonLoc.
-    if (!InitValWithAdjustments.getAs<NonLoc>())
+    if (!InitValWithAdjustments.getAs<NonLoc>()) {
+      if (OutRegionWithAdjustments)
+        *OutRegionWithAdjustments = nullptr;
       return State;
+    }
     Result = InitWithAdjustments;
   } else {
     // We need to create a region no matter what. For sanity, make sure we don't
@@ -418,11 +420,17 @@ ExprEngine::createTemporaryRegionIfNeeded(ProgramStateRef State,
   // The result expression would now point to the correct sub-region of the
   // newly created temporary region. Do this last in order to getSVal of Init
   // correctly in case (Result == Init).
-  State = State->BindExpr(Result, LC, Reg);
+  if (Result->isGLValue()) {
+    State = State->BindExpr(Result, LC, Reg);
+  } else {
+    State = State->BindExpr(Result, LC, InitValWithAdjustments);
+  }
 
   // Notify checkers once for two bindLoc()s.
   State = processRegionChange(State, TR, LC);
 
+  if (OutRegionWithAdjustments)
+    *OutRegionWithAdjustments = cast<SubRegion>(Reg.getAsRegion());
   return State;
 }
 
@@ -2532,8 +2540,12 @@ void ExprEngine::VisitMemberExpr(const MemberExpr *M, ExplodedNode *Pred,
       }
 
       // Handle regular struct fields / member variables.
-      state = createTemporaryRegionIfNeeded(state, LCtx, BaseExpr);
-      SVal baseExprVal = state->getSVal(BaseExpr, LCtx);
+      const SubRegion *MR = nullptr;
+      state = createTemporaryRegionIfNeeded(state, LCtx, BaseExpr,
+                                            /*Result=*/nullptr,
+                                            /*OutRegionWithAdjustments=*/&MR);
+      SVal baseExprVal =
+          MR ? loc::MemRegionVal(MR) : state->getSVal(BaseExpr, LCtx);
 
       const auto *field = cast<FieldDecl>(Member);
       SVal L = state->getLValue(field, baseExprVal);