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authordim <dim@FreeBSD.org>2011-02-20 13:06:31 +0000
committerdim <dim@FreeBSD.org>2011-02-20 13:06:31 +0000
commit39fcc9a984e2820e4ea0fa2ac4abd17d9f3a31df (patch)
treea9243275843fbeaa590afc07ee888e006b8d54ea /lib/StaticAnalyzer/Core/SValBuilder.cpp
parent69b4eca4a4255ba43baa5c1d9bbdec3ec17f479e (diff)
downloadFreeBSD-src-39fcc9a984e2820e4ea0fa2ac4abd17d9f3a31df.zip
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Vendor import of clang trunk r126079:
http://llvm.org/svn/llvm-project/cfe/trunk@126079
Diffstat (limited to 'lib/StaticAnalyzer/Core/SValBuilder.cpp')
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1 files changed, 310 insertions, 0 deletions
diff --git a/lib/StaticAnalyzer/Core/SValBuilder.cpp b/lib/StaticAnalyzer/Core/SValBuilder.cpp
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+// SValBuilder.cpp - Basic class for all SValBuilder implementations -*- C++ -*-
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines SValBuilder, the base class for all (complete) SValBuilder
+// implementations.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/GRState.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h"
+
+using namespace clang;
+using namespace ento;
+
+//===----------------------------------------------------------------------===//
+// Basic SVal creation.
+//===----------------------------------------------------------------------===//
+
+DefinedOrUnknownSVal SValBuilder::makeZeroVal(QualType T) {
+ if (Loc::isLocType(T))
+ return makeNull();
+
+ if (T->isIntegerType())
+ return makeIntVal(0, T);
+
+ // FIXME: Handle floats.
+ // FIXME: Handle structs.
+ return UnknownVal();
+}
+
+
+NonLoc SValBuilder::makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op,
+ const llvm::APSInt& v, QualType T) {
+ // The Environment ensures we always get a persistent APSInt in
+ // BasicValueFactory, so we don't need to get the APSInt from
+ // BasicValueFactory again.
+ assert(!Loc::isLocType(T));
+ return nonloc::SymExprVal(SymMgr.getSymIntExpr(lhs, op, v, T));
+}
+
+NonLoc SValBuilder::makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op,
+ const SymExpr *rhs, QualType T) {
+ assert(SymMgr.getType(lhs) == SymMgr.getType(rhs));
+ assert(!Loc::isLocType(T));
+ return nonloc::SymExprVal(SymMgr.getSymSymExpr(lhs, op, rhs, T));
+}
+
+
+SVal SValBuilder::convertToArrayIndex(SVal V) {
+ if (V.isUnknownOrUndef())
+ return V;
+
+ // Common case: we have an appropriately sized integer.
+ if (nonloc::ConcreteInt* CI = dyn_cast<nonloc::ConcreteInt>(&V)) {
+ const llvm::APSInt& I = CI->getValue();
+ if (I.getBitWidth() == ArrayIndexWidth && I.isSigned())
+ return V;
+ }
+
+ return evalCastNL(cast<NonLoc>(V), ArrayIndexTy);
+}
+
+DefinedOrUnknownSVal
+SValBuilder::getRegionValueSymbolVal(const TypedRegion* R) {
+ QualType T = R->getValueType();
+
+ if (!SymbolManager::canSymbolicate(T))
+ return UnknownVal();
+
+ SymbolRef sym = SymMgr.getRegionValueSymbol(R);
+
+ if (Loc::isLocType(T))
+ return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
+
+ return nonloc::SymbolVal(sym);
+}
+
+DefinedOrUnknownSVal SValBuilder::getConjuredSymbolVal(const void *SymbolTag,
+ const Expr *E,
+ unsigned Count) {
+ QualType T = E->getType();
+
+ if (!SymbolManager::canSymbolicate(T))
+ return UnknownVal();
+
+ SymbolRef sym = SymMgr.getConjuredSymbol(E, Count, SymbolTag);
+
+ if (Loc::isLocType(T))
+ return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
+
+ return nonloc::SymbolVal(sym);
+}
+
+DefinedOrUnknownSVal SValBuilder::getConjuredSymbolVal(const void *SymbolTag,
+ const Expr *E,
+ QualType T,
+ unsigned Count) {
+
+ if (!SymbolManager::canSymbolicate(T))
+ return UnknownVal();
+
+ SymbolRef sym = SymMgr.getConjuredSymbol(E, T, Count, SymbolTag);
+
+ if (Loc::isLocType(T))
+ return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
+
+ return nonloc::SymbolVal(sym);
+}
+
+DefinedSVal SValBuilder::getMetadataSymbolVal(const void *SymbolTag,
+ const MemRegion *MR,
+ const Expr *E, QualType T,
+ unsigned Count) {
+ assert(SymbolManager::canSymbolicate(T) && "Invalid metadata symbol type");
+
+ SymbolRef sym = SymMgr.getMetadataSymbol(MR, E, T, Count, SymbolTag);
+
+ if (Loc::isLocType(T))
+ return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
+
+ return nonloc::SymbolVal(sym);
+}
+
+DefinedOrUnknownSVal
+SValBuilder::getDerivedRegionValueSymbolVal(SymbolRef parentSymbol,
+ const TypedRegion *R) {
+ QualType T = R->getValueType();
+
+ if (!SymbolManager::canSymbolicate(T))
+ return UnknownVal();
+
+ SymbolRef sym = SymMgr.getDerivedSymbol(parentSymbol, R);
+
+ if (Loc::isLocType(T))
+ return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
+
+ return nonloc::SymbolVal(sym);
+}
+
+DefinedSVal SValBuilder::getFunctionPointer(const FunctionDecl* FD) {
+ return loc::MemRegionVal(MemMgr.getFunctionTextRegion(FD));
+}
+
+DefinedSVal SValBuilder::getBlockPointer(const BlockDecl *D,
+ CanQualType locTy,
+ const LocationContext *LC) {
+ const BlockTextRegion *BC =
+ MemMgr.getBlockTextRegion(D, locTy, LC->getAnalysisContext());
+ const BlockDataRegion *BD = MemMgr.getBlockDataRegion(BC, LC);
+ return loc::MemRegionVal(BD);
+}
+
+//===----------------------------------------------------------------------===//
+
+SVal SValBuilder::evalBinOp(const GRState *ST, BinaryOperator::Opcode Op,
+ SVal L, SVal R, QualType T) {
+
+ if (L.isUndef() || R.isUndef())
+ return UndefinedVal();
+
+ if (L.isUnknown() || R.isUnknown())
+ return UnknownVal();
+
+ if (isa<Loc>(L)) {
+ if (isa<Loc>(R))
+ return evalBinOpLL(ST, Op, cast<Loc>(L), cast<Loc>(R), T);
+
+ return evalBinOpLN(ST, Op, cast<Loc>(L), cast<NonLoc>(R), T);
+ }
+
+ if (isa<Loc>(R)) {
+ // Support pointer arithmetic where the addend is on the left
+ // and the pointer on the right.
+ assert(Op == BO_Add);
+
+ // Commute the operands.
+ return evalBinOpLN(ST, Op, cast<Loc>(R), cast<NonLoc>(L), T);
+ }
+
+ return evalBinOpNN(ST, Op, cast<NonLoc>(L), cast<NonLoc>(R), T);
+}
+
+DefinedOrUnknownSVal SValBuilder::evalEQ(const GRState *ST,
+ DefinedOrUnknownSVal L,
+ DefinedOrUnknownSVal R) {
+ return cast<DefinedOrUnknownSVal>(evalBinOp(ST, BO_EQ, L, R,
+ Context.IntTy));
+}
+
+// FIXME: should rewrite according to the cast kind.
+SVal SValBuilder::evalCast(SVal val, QualType castTy, QualType originalTy) {
+ if (val.isUnknownOrUndef() || castTy == originalTy)
+ return val;
+
+ // For const casts, just propagate the value.
+ if (!castTy->isVariableArrayType() && !originalTy->isVariableArrayType())
+ if (Context.hasSameUnqualifiedType(castTy, originalTy))
+ return val;
+
+ // Check for casts to real or complex numbers. We don't handle these at all
+ // right now.
+ if (castTy->isFloatingType() || castTy->isAnyComplexType())
+ return UnknownVal();
+
+ // Check for casts from integers to integers.
+ if (castTy->isIntegerType() && originalTy->isIntegerType())
+ return evalCastNL(cast<NonLoc>(val), castTy);
+
+ // Check for casts from pointers to integers.
+ if (castTy->isIntegerType() && Loc::isLocType(originalTy))
+ return evalCastL(cast<Loc>(val), castTy);
+
+ // Check for casts from integers to pointers.
+ if (Loc::isLocType(castTy) && originalTy->isIntegerType()) {
+ if (nonloc::LocAsInteger *LV = dyn_cast<nonloc::LocAsInteger>(&val)) {
+ if (const MemRegion *R = LV->getLoc().getAsRegion()) {
+ StoreManager &storeMgr = StateMgr.getStoreManager();
+ R = storeMgr.castRegion(R, castTy);
+ return R ? SVal(loc::MemRegionVal(R)) : UnknownVal();
+ }
+ return LV->getLoc();
+ }
+ goto DispatchCast;
+ }
+
+ // Just pass through function and block pointers.
+ if (originalTy->isBlockPointerType() || originalTy->isFunctionPointerType()) {
+ assert(Loc::isLocType(castTy));
+ return val;
+ }
+
+ // Check for casts from array type to another type.
+ if (originalTy->isArrayType()) {
+ // We will always decay to a pointer.
+ val = StateMgr.ArrayToPointer(cast<Loc>(val));
+
+ // Are we casting from an array to a pointer? If so just pass on
+ // the decayed value.
+ if (castTy->isPointerType())
+ return val;
+
+ // Are we casting from an array to an integer? If so, cast the decayed
+ // pointer value to an integer.
+ assert(castTy->isIntegerType());
+
+ // FIXME: Keep these here for now in case we decide soon that we
+ // need the original decayed type.
+ // QualType elemTy = cast<ArrayType>(originalTy)->getElementType();
+ // QualType pointerTy = C.getPointerType(elemTy);
+ return evalCastL(cast<Loc>(val), castTy);
+ }
+
+ // Check for casts from a region to a specific type.
+ if (const MemRegion *R = val.getAsRegion()) {
+ // FIXME: We should handle the case where we strip off view layers to get
+ // to a desugared type.
+
+ if (!Loc::isLocType(castTy)) {
+ // FIXME: There can be gross cases where one casts the result of a function
+ // (that returns a pointer) to some other value that happens to fit
+ // within that pointer value. We currently have no good way to
+ // model such operations. When this happens, the underlying operation
+ // is that the caller is reasoning about bits. Conceptually we are
+ // layering a "view" of a location on top of those bits. Perhaps
+ // we need to be more lazy about mutual possible views, even on an
+ // SVal? This may be necessary for bit-level reasoning as well.
+ return UnknownVal();
+ }
+
+ // We get a symbolic function pointer for a dereference of a function
+ // pointer, but it is of function type. Example:
+
+ // struct FPRec {
+ // void (*my_func)(int * x);
+ // };
+ //
+ // int bar(int x);
+ //
+ // int f1_a(struct FPRec* foo) {
+ // int x;
+ // (*foo->my_func)(&x);
+ // return bar(x)+1; // no-warning
+ // }
+
+ assert(Loc::isLocType(originalTy) || originalTy->isFunctionType() ||
+ originalTy->isBlockPointerType() || castTy->isReferenceType());
+
+ StoreManager &storeMgr = StateMgr.getStoreManager();
+
+ // Delegate to store manager to get the result of casting a region to a
+ // different type. If the MemRegion* returned is NULL, this expression
+ // Evaluates to UnknownVal.
+ R = storeMgr.castRegion(R, castTy);
+ return R ? SVal(loc::MemRegionVal(R)) : UnknownVal();
+ }
+
+DispatchCast:
+ // All other cases.
+ return isa<Loc>(val) ? evalCastL(cast<Loc>(val), castTy)
+ : evalCastNL(cast<NonLoc>(val), castTy);
+}
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