Split libAnalysis into two libraries: libAnalysis and libChecker.

(1) libAnalysis is a generic analysis library that can be used by
    Sema.  It defines the CFG, basic dataflow analysis primitives, and
    inexpensive flow-sensitive analyses (e.g. LiveVariables).

(2) libChecker contains the guts of the static analyzer, incuding the
    path-sensitive analysis engine and domain-specific checks.

Now any clients that want to use the frontend to build their own tools
don't need to link in the entire static analyzer.

This change exposes various obvious cleanups that can be made to the
layout of files and headers in libChecker.  More changes pending.  :)

This change also exposed a layering violation between AnalysisContext
and MemRegion.  BlockInvocationContext shouldn't explicitly know about
BlockDataRegions.  For now I've removed the BlockDataRegion* from
BlockInvocationContext (removing context-sensitivity; although this
wasn't used yet).  We need to have a better way to extend
BlockInvocationContext (and any LocationContext) to add
context-sensitivty.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@94406 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 86 insertions, 0 deletions

diff --git a/lib/Checker/UndefResultChecker.cpp b/lib/Checker/UndefResultChecker.cpp
new file mode 100644
index 0000000000..4408c471d2
--- /dev/null
+++ b/lib/Checker/UndefResultChecker.cpp
@@ -0,0 +1,86 @@
+//=== UndefResultChecker.cpp ------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This defines UndefResultChecker, a builtin check in GRExprEngine that 
+// performs checks for undefined results of non-assignment binary operators.
+//
+//===----------------------------------------------------------------------===//
+
+#include "GRExprEngineInternalChecks.h"
+#include "clang/Checker/PathSensitive/CheckerVisitor.h"
+#include "clang/Checker/PathSensitive/GRExprEngine.h"
+#include "clang/Checker/PathSensitive/BugReporter.h"
+
+using namespace clang;
+
+namespace {
+class UndefResultChecker 
+  : public CheckerVisitor<UndefResultChecker> {
+
+  BugType *BT;
+  
+public:
+  UndefResultChecker() : BT(0) {}
+  static void *getTag() { static int tag = 0; return &tag; }
+  void PostVisitBinaryOperator(CheckerContext &C, const BinaryOperator *B);
+};
+} // end anonymous namespace
+
+void clang::RegisterUndefResultChecker(GRExprEngine &Eng) {
+  Eng.registerCheck(new UndefResultChecker());
+}
+
+void UndefResultChecker::PostVisitBinaryOperator(CheckerContext &C, 
+                                                 const BinaryOperator *B) {
+  const GRState *state = C.getState();
+  if (state->getSVal(B).isUndef()) {
+    // Generate an error node.
+    ExplodedNode *N = C.GenerateSink();
+    if (!N)
+      return;
+    
+    if (!BT)
+      BT = new BuiltinBug("Result of operation is garbage or undefined");
+
+    llvm::SmallString<256> sbuf;
+    llvm::raw_svector_ostream OS(sbuf);
+    const Expr *Ex = NULL;
+    bool isLeft = true;
+    
+    if (state->getSVal(B->getLHS()).isUndef()) {
+      Ex = B->getLHS()->IgnoreParenCasts();
+      isLeft = true;
+    }
+    else if (state->getSVal(B->getRHS()).isUndef()) {
+      Ex = B->getRHS()->IgnoreParenCasts();
+      isLeft = false;
+    }
+    
+    if (Ex) {
+      OS << "The " << (isLeft ? "left" : "right")
+         << " operand of '"
+         << BinaryOperator::getOpcodeStr(B->getOpcode())
+         << "' is a garbage value";
+    }          
+    else {
+      // Neither operand was undefined, but the result is undefined.
+      OS << "The result of the '"
+         << BinaryOperator::getOpcodeStr(B->getOpcode())
+         << "' expression is undefined";
+    }
+    EnhancedBugReport *report = new EnhancedBugReport(*BT, OS.str(), N);
+    if (Ex) {
+      report->addRange(Ex->getSourceRange());
+      report->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue, Ex);
+    }
+    else
+      report->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue, B);
+    C.EmitReport(report);
+  }
+}