From: Jordan Rose <jordan_rose@apple.com>
Date: Sat, 8 Sep 2012 01:24:53 +0000 (+0000)
Subject: [analyzer] Remove constraints on dead symbols as part of removeDeadBindings.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=24c7f98828e039005cff3bd847e7ab404a6a09f8;p=clang

[analyzer] Remove constraints on dead symbols as part of removeDeadBindings.

Previously, we'd just keep constraints around forever, which means we'd
never be able to merge paths that differed only in constraints on dead
symbols.

Because we now allow constraints on symbolic expressions, not just single
symbols, this requires changing SymExpr::symbol_iterator to include
intermediate symbol nodes in its traversal, not just the SymbolData leaf
nodes.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@163444 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/StaticAnalyzer/Core/ProgramState.cpp b/lib/StaticAnalyzer/Core/ProgramState.cpp
index ed8e1dc9ec..3c7e28e946 100644
--- a/lib/StaticAnalyzer/Core/ProgramState.cpp
+++ b/lib/StaticAnalyzer/Core/ProgramState.cpp
@@ -106,8 +106,9 @@ ProgramStateManager::removeDeadBindings(ProgramStateRef state,
                                                    SymReaper);
   NewState.setStore(newStore);
   SymReaper.setReapedStore(newStore);
-  
-  return getPersistentState(NewState);
+
+  ProgramStateRef Result = getPersistentState(NewState);
+  return ConstraintMgr->removeDeadBindings(Result, SymReaper);
 }
 
 ProgramStateRef ProgramStateManager::MarshalState(ProgramStateRef state,
@@ -697,7 +698,9 @@ bool ProgramState::isTainted(SymbolRef Sym, TaintTagType Kind) const {
   bool Tainted = false;
   for (SymExpr::symbol_iterator SI = Sym->symbol_begin(), SE =Sym->symbol_end();
        SI != SE; ++SI) {
-    assert(isa<SymbolData>(*SI));
+    if (!isa<SymbolData>(*SI))
+      continue;
+    
     const TaintTagType *Tag = get<TaintMap>(*SI);
     Tainted = (Tag && *Tag == Kind);
 
diff --git a/lib/StaticAnalyzer/Core/SymbolManager.cpp b/lib/StaticAnalyzer/Core/SymbolManager.cpp
index c21df4c318..16fc5408f5 100644
--- a/lib/StaticAnalyzer/Core/SymbolManager.cpp
+++ b/lib/StaticAnalyzer/Core/SymbolManager.cpp
@@ -117,21 +117,17 @@ bool SymExpr::symbol_iterator::operator!=(const symbol_iterator &X) const {
 
 SymExpr::symbol_iterator::symbol_iterator(const SymExpr *SE) {
   itr.push_back(SE);
-  while (!isa<SymbolData>(itr.back())) expand();
 }
 
 SymExpr::symbol_iterator &SymExpr::symbol_iterator::operator++() {
   assert(!itr.empty() && "attempting to iterate on an 'end' iterator");
-  assert(isa<SymbolData>(itr.back()));
-  itr.pop_back();
-  if (!itr.empty())
-    while (!isa<SymbolData>(itr.back())) expand();
+  expand();
   return *this;
 }
 
 SymbolRef SymExpr::symbol_iterator::operator*() {
   assert(!itr.empty() && "attempting to dereference an 'end' iterator");
-  return cast<SymbolData>(itr.back());
+  return itr.back();
 }
 
 void SymExpr::symbol_iterator::expand() {
diff --git a/test/Analysis/traversal-path-unification.c b/test/Analysis/traversal-path-unification.c
new file mode 100644
index 0000000000..0a45f48a01
--- /dev/null
+++ b/test/Analysis/traversal-path-unification.c
@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -analyze -analyzer-checker=core,debug.DumpTraversal %s | FileCheck %s
+
+int a();
+int b();
+int c();
+
+void testRemoveDeadBindings() {
+  int i = a();
+  if (i)
+    a();
+  else
+    b();
+
+  // At this point the symbol bound to 'i' is dead.
+  // The effects of a() and b() are identical (they both invalidate globals).
+  // We should unify the two paths here and only get one end-of-path node.
+  c();
+}
+
+// CHECK: --END PATH--
+// CHECK-NOT: --END PATH--
\ No newline at end of file