From ce6644bc1e921833f9b3c10cf7d4a0b78e8d5dc9 Mon Sep 17 00:00:00 2001
From: Jordan Rose <jordan_rose@apple.com>
Date: Sat, 29 Sep 2012 01:36:51 +0000
Subject: [PATCH] Revert "[analyzer] Create a temporary region for rvalue
 structs when accessing fields"

This reverts commit 6f61df3e7256413dcb99afb9673f4206e3c4992c.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@164877 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/StaticAnalyzer/Core/ExprEngine.cpp | 18 +++++++++---------
 test/Analysis/fields.c                 | 11 +----------
 test/Analysis/reference.cpp            |  4 +++-
 3 files changed, 13 insertions(+), 20 deletions(-)

diff --git a/lib/StaticAnalyzer/Core/ExprEngine.cpp b/lib/StaticAnalyzer/Core/ExprEngine.cpp
index 06216f83ea..8e2c159ca7 100644
--- a/lib/StaticAnalyzer/Core/ExprEngine.cpp
+++ b/lib/StaticAnalyzer/Core/ExprEngine.cpp
@@ -1505,17 +1505,17 @@ void ExprEngine::VisitMemberExpr(const MemberExpr *M, ExplodedNode *Pred,
   ProgramStateRef state = Pred->getState();
   const LocationContext *LCtx = Pred->getLocationContext();
   SVal baseExprVal = state->getSVal(baseExpr, Pred->getLocationContext());
-
-  // If we're accessing a field of an rvalue, we need to treat it like a
-  // temporary object.
-  if (isa<NonLoc>(baseExprVal)) {
-    const MemRegion *R  =
-      svalBuilder.getRegionManager().getCXXTempObjectRegion(baseExpr, LCtx);
-    SVal L = loc::MemRegionVal(R);
-    state = state->bindLoc(L, baseExprVal);
-    baseExprVal = L;
+  if (isa<nonloc::LazyCompoundVal>(baseExprVal) ||
+      isa<nonloc::CompoundVal>(baseExprVal) ||
+      // FIXME: This can originate by conjuring a symbol for an unknown
+      // temporary struct object, see test/Analysis/fields.c:
+      // (p = getit()).x
+      isa<nonloc::SymbolVal>(baseExprVal)) {
+    Bldr.generateNode(M, Pred, state->BindExpr(M, LCtx, UnknownVal()));
+    return;
   }
 
+  // For all other cases, compute an lvalue.    
   SVal L = state->getLValue(field, baseExprVal);
   if (M->isGLValue()) {
     ExplodedNodeSet Tmp;
diff --git a/test/Analysis/fields.c b/test/Analysis/fields.c
index a2b3dcf738..a10d5a8060 100644
--- a/test/Analysis/fields.c
+++ b/test/Analysis/fields.c
@@ -1,6 +1,4 @@
-// RUN: %clang_cc1 -analyze -analyzer-checker=core,alpha.core,debug.ExprInspection %s -analyzer-store=region -verify
-
-void clang_analyzer_eval(int);
+// RUN: %clang_cc1 -analyze -analyzer-checker=core,alpha.core %s -analyzer-store=region -verify
 
 unsigned foo();
 typedef struct bf { unsigned x:2; } bf;
@@ -35,10 +33,3 @@ void testNullAddress() {
   int *px = &p->x; // expected-warning{{Access to field 'x' results in a dereference of a null pointer (loaded from variable 'p')}}
   *px = 1; // No warning because analysis stops at the previous line.
 }
-
-void testLazyCompoundVal() {
-  Point p = {42, 0};
-  Point q;
-  clang_analyzer_eval((q = p).x == 42); // expected-warning{{TRUE}}
-  clang_analyzer_eval(q.x == 42); // expected-warning{{TRUE}}
-}
diff --git a/test/Analysis/reference.cpp b/test/Analysis/reference.cpp
index ce0ee8ed57..374f3f7261 100644
--- a/test/Analysis/reference.cpp
+++ b/test/Analysis/reference.cpp
@@ -116,8 +116,10 @@ void testReferenceAddress(int &x) {
 
   struct S { int &x; };
 
+  // FIXME: Should be TRUE. Fields of return-by-value structs are not yet
+  // symbolicated. Tracked by <rdar://problem/12137950>.
   extern S getS();
-  clang_analyzer_eval(&getS().x != 0); // expected-warning{{TRUE}}
+  clang_analyzer_eval(&getS().x != 0); // expected-warning{{UNKNOWN}}
 
   extern S *getSP();
   clang_analyzer_eval(&getSP()->x != 0); // expected-warning{{TRUE}}
-- 
2.40.0