Refactor OSAtomic evaluation logic into OSAtomicChecker.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@90968 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/OSAtomicChecker.cpp b/lib/Analysis/OSAtomicChecker.cpp
new file mode 100644
index 0000000..03e9e38
--- /dev/null
+++ b/lib/Analysis/OSAtomicChecker.cpp
@@ -0,0 +1,187 @@
+//=== OSAtomicChecker.cpp - OSAtomic functions evaluator --------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This checker evaluates OSAtomic functions.
+//
+//===----------------------------------------------------------------------===//
+
+#include "GRExprEngineInternalChecks.h"
+#include "clang/Analysis/PathSensitive/Checker.h"
+#include "clang/Basic/Builtins.h"
+#include "llvm/ADT/StringSwitch.h"
+
+using namespace clang;
+
+namespace {
+
+class OSAtomicChecker : public Checker {
+public:
+ static void *getTag() { static int tag = 0; return &tag; }
+ virtual bool EvalCallExpr(CheckerContext &C, const CallExpr *CE);
+
+private:
+ bool EvalOSAtomicCompareAndSwap(CheckerContext &C, const CallExpr *CE);
+};
+
+}
+
+void clang::RegisterOSAtomicChecker(GRExprEngine &Eng) {
+ Eng.registerCheck(new OSAtomicChecker());
+}
+
+bool OSAtomicChecker::EvalCallExpr(CheckerContext &C,const CallExpr *CE) {
+ const GRState *state = C.getState();
+ const Expr *Callee = CE->getCallee();
+ SVal L = state->getSVal(Callee);
+
+ const FunctionDecl* FD = L.getAsFunctionDecl();
+ if (!FD)
+ return false;
+
+ const char *FName = FD->getNameAsCString();
+
+ // Check for compare and swap.
+ if (strncmp(FName, "OSAtomicCompareAndSwap", 22) == 0 ||
+ strncmp(FName, "objc_atomicCompareAndSwap", 25) == 0)
+ return EvalOSAtomicCompareAndSwap(C, CE);
+
+ // FIXME: Other atomics.
+ return false;
+}
+
+bool OSAtomicChecker::EvalOSAtomicCompareAndSwap(CheckerContext &C,
+ const CallExpr *CE) {
+ // Not enough arguments to match OSAtomicCompareAndSwap?
+ if (CE->getNumArgs() != 3)
+ return false;
+
+ ASTContext &Ctx = C.getASTContext();
+ const Expr *oldValueExpr = CE->getArg(0);
+ QualType oldValueType = Ctx.getCanonicalType(oldValueExpr->getType());
+
+ const Expr *newValueExpr = CE->getArg(1);
+ QualType newValueType = Ctx.getCanonicalType(newValueExpr->getType());
+
+ // Do the types of 'oldValue' and 'newValue' match?
+ if (oldValueType != newValueType)
+ return false;
+
+ const Expr *theValueExpr = CE->getArg(2);
+ const PointerType *theValueType=theValueExpr->getType()->getAs<PointerType>();
+
+ // theValueType not a pointer?
+ if (!theValueType)
+ return false;
+
+ QualType theValueTypePointee =
+ Ctx.getCanonicalType(theValueType->getPointeeType()).getUnqualifiedType();
+
+ // The pointee must match newValueType and oldValueType.
+ if (theValueTypePointee != newValueType)
+ return false;
+
+ static unsigned magic_load = 0;
+ static unsigned magic_store = 0;
+
+ const void *OSAtomicLoadTag = &magic_load;
+ const void *OSAtomicStoreTag = &magic_store;
+
+ // Load 'theValue'.
+ GRExprEngine &Engine = C.getEngine();
+ const GRState *state = C.getState();
+ ExplodedNodeSet Tmp;
+ SVal location = state->getSVal(theValueExpr);
+ // Here we should use the value type of the region as the load type.
+ const MemRegion *R = location.getAsRegion()->StripCasts();
+ QualType LoadTy;
+ if (R) {
+ LoadTy = cast<TypedRegion>(R)->getValueType(Ctx);
+ location = loc::MemRegionVal(R);
+ }
+ Engine.EvalLoad(Tmp, const_cast<Expr *>(theValueExpr), C.getPredecessor(),
+ state, location, OSAtomicLoadTag, LoadTy);
+
+ if (Tmp.empty()) {
+ // If no nodes were generated, other checkers must generated sinks. But
+ // since the builder state was restored, we set it manually to prevent
+ // auto transition.
+ // FIXME: there should be a better approach.
+ C.getNodeBuilder().BuildSinks = true;
+ return true;
+ }
+
+ for (ExplodedNodeSet::iterator I = Tmp.begin(), E = Tmp.end();
+ I != E; ++I) {
+
+ ExplodedNode *N = *I;
+ const GRState *stateLoad = N->getState();
+ SVal theValueVal_untested = stateLoad->getSVal(theValueExpr);
+ SVal oldValueVal_untested = stateLoad->getSVal(oldValueExpr);
+
+ // FIXME: Issue an error.
+ if (theValueVal_untested.isUndef() || oldValueVal_untested.isUndef()) {
+ return false;
+ }
+
+ DefinedOrUnknownSVal theValueVal =
+ cast<DefinedOrUnknownSVal>(theValueVal_untested);
+ DefinedOrUnknownSVal oldValueVal =
+ cast<DefinedOrUnknownSVal>(oldValueVal_untested);
+
+ SValuator &SVator = Engine.getSValuator();
+
+ // Perform the comparison.
+ DefinedOrUnknownSVal Cmp = SVator.EvalEQ(stateLoad,theValueVal,oldValueVal);
+
+ const GRState *stateEqual = stateLoad->Assume(Cmp, true);
+
+ // Were they equal?
+ if (stateEqual) {
+ // Perform the store.
+ ExplodedNodeSet TmpStore;
+ SVal val = stateEqual->getSVal(newValueExpr);
+
+ // Handle implicit value casts.
+ if (const TypedRegion *R =
+ dyn_cast_or_null<TypedRegion>(location.getAsRegion())) {
+ llvm::tie(state, val) = SVator.EvalCast(val, state,R->getValueType(Ctx),
+ newValueExpr->getType());
+ }
+
+ Engine.EvalStore(TmpStore, NULL, const_cast<Expr *>(theValueExpr), N,
+ stateEqual, location, val, OSAtomicStoreTag);
+
+ if (TmpStore.empty()) {
+ // If no nodes were generated, other checkers must generated sinks. But
+ // since the builder state was restored, we set it manually to prevent
+ // auto transition.
+ // FIXME: there should be a better approach.
+ C.getNodeBuilder().BuildSinks = true;
+ return true;
+ }
+
+ // Now bind the result of the comparison.
+ for (ExplodedNodeSet::iterator I2 = TmpStore.begin(),
+ E2 = TmpStore.end(); I2 != E2; ++I2) {
+ ExplodedNode *predNew = *I2;
+ const GRState *stateNew = predNew->getState();
+ SVal Res = Engine.getValueManager().makeTruthVal(true, CE->getType());
+ C.GenerateNode(stateNew->BindExpr(CE, Res), predNew);
+ }
+ }
+
+ // Were they not equal?
+ if (const GRState *stateNotEqual = stateLoad->Assume(Cmp, false)) {
+ SVal Res = Engine.getValueManager().makeTruthVal(false, CE->getType());
+ C.GenerateNode(stateNotEqual->BindExpr(CE, Res), N);
+ }
+ }
+
+ return true;
+}