1 files changed, 345 insertions, 0 deletions
diff --git a/lib/StaticAnalyzer/Core/SymbolManager.cpp b/lib/StaticAnalyzer/Core/SymbolManager.cpp
new file mode 100644
index 0000000..c1ca1cf
--- /dev/null
+++ b/lib/StaticAnalyzer/Core/SymbolManager.cpp
@@ -0,0 +1,345 @@
+//== SymbolManager.h - Management of Symbolic Values ------------*- 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 SymbolManager, a class that manages symbolic values
+//  created for use by ExprEngine and related classes.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
+#include "clang/Analysis/Analyses/LiveVariables.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace clang;
+using namespace ento;
+
+void SymExpr::dump() const {
+  dumpToStream(llvm::errs());
+}
+
+static void print(llvm::raw_ostream& os, BinaryOperator::Opcode Op) {
+  switch (Op) {
+    default:
+      assert(false && "operator printing not implemented");
+      break;
+    case BO_Mul: os << '*'  ; break;
+    case BO_Div: os << '/'  ; break;
+    case BO_Rem: os << '%'  ; break;
+    case BO_Add: os << '+'  ; break;
+    case BO_Sub: os << '-'  ; break;
+    case BO_Shl: os << "<<" ; break;
+    case BO_Shr: os << ">>" ; break;
+    case BO_LT:  os << "<"  ; break;
+    case BO_GT:  os << '>'  ; break;
+    case BO_LE:  os << "<=" ; break;
+    case BO_GE:  os << ">=" ; break;
+    case BO_EQ:  os << "==" ; break;
+    case BO_NE:  os << "!=" ; break;
+    case BO_And: os << '&'  ; break;
+    case BO_Xor: os << '^'  ; break;
+    case BO_Or:  os << '|'  ; break;
+  }
+}
+
+void SymIntExpr::dumpToStream(llvm::raw_ostream& os) const {
+  os << '(';
+  getLHS()->dumpToStream(os);
+  os << ") ";
+  print(os, getOpcode());
+  os << ' ' << getRHS().getZExtValue();
+  if (getRHS().isUnsigned()) os << 'U';
+}
+
+void SymSymExpr::dumpToStream(llvm::raw_ostream& os) const {
+  os << '(';
+  getLHS()->dumpToStream(os);
+  os << ") ";
+  os << '(';
+  getRHS()->dumpToStream(os);
+  os << ')';
+}
+
+void SymbolConjured::dumpToStream(llvm::raw_ostream& os) const {
+  os << "conj_$" << getSymbolID() << '{' << T.getAsString() << '}';
+}
+
+void SymbolDerived::dumpToStream(llvm::raw_ostream& os) const {
+  os << "derived_$" << getSymbolID() << '{'
+     << getParentSymbol() << ',' << getRegion() << '}';
+}
+
+void SymbolExtent::dumpToStream(llvm::raw_ostream& os) const {
+  os << "extent_$" << getSymbolID() << '{' << getRegion() << '}';
+}
+
+void SymbolMetadata::dumpToStream(llvm::raw_ostream& os) const {
+  os << "meta_$" << getSymbolID() << '{'
+     << getRegion() << ',' << T.getAsString() << '}';
+}
+
+void SymbolRegionValue::dumpToStream(llvm::raw_ostream& os) const {
+  os << "reg_$" << getSymbolID() << "<" << R << ">";
+}
+
+const SymbolRegionValue*
+SymbolManager::getRegionValueSymbol(const TypedRegion* R) {
+  llvm::FoldingSetNodeID profile;
+  SymbolRegionValue::Profile(profile, R);
+  void* InsertPos;
+  SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
+  if (!SD) {
+    SD = (SymExpr*) BPAlloc.Allocate<SymbolRegionValue>();
+    new (SD) SymbolRegionValue(SymbolCounter, R);
+    DataSet.InsertNode(SD, InsertPos);
+    ++SymbolCounter;
+  }
+
+  return cast<SymbolRegionValue>(SD);
+}
+
+const SymbolConjured*
+SymbolManager::getConjuredSymbol(const Stmt* E, QualType T, unsigned Count,
+                                 const void* SymbolTag) {
+
+  llvm::FoldingSetNodeID profile;
+  SymbolConjured::Profile(profile, E, T, Count, SymbolTag);
+  void* InsertPos;
+  SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
+  if (!SD) {
+    SD = (SymExpr*) BPAlloc.Allocate<SymbolConjured>();
+    new (SD) SymbolConjured(SymbolCounter, E, T, Count, SymbolTag);
+    DataSet.InsertNode(SD, InsertPos);
+    ++SymbolCounter;
+  }
+
+  return cast<SymbolConjured>(SD);
+}
+
+const SymbolDerived*
+SymbolManager::getDerivedSymbol(SymbolRef parentSymbol,
+                                const TypedRegion *R) {
+
+  llvm::FoldingSetNodeID profile;
+  SymbolDerived::Profile(profile, parentSymbol, R);
+  void* InsertPos;
+  SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
+  if (!SD) {
+    SD = (SymExpr*) BPAlloc.Allocate<SymbolDerived>();
+    new (SD) SymbolDerived(SymbolCounter, parentSymbol, R);
+    DataSet.InsertNode(SD, InsertPos);
+    ++SymbolCounter;
+  }
+
+  return cast<SymbolDerived>(SD);
+}
+
+const SymbolExtent*
+SymbolManager::getExtentSymbol(const SubRegion *R) {
+  llvm::FoldingSetNodeID profile;
+  SymbolExtent::Profile(profile, R);
+  void* InsertPos;
+  SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
+  if (!SD) {
+    SD = (SymExpr*) BPAlloc.Allocate<SymbolExtent>();
+    new (SD) SymbolExtent(SymbolCounter, R);
+    DataSet.InsertNode(SD, InsertPos);
+    ++SymbolCounter;
+  }
+
+  return cast<SymbolExtent>(SD);
+}
+
+const SymbolMetadata*
+SymbolManager::getMetadataSymbol(const MemRegion* R, const Stmt* S, QualType T,
+                                 unsigned Count, const void* SymbolTag) {
+
+  llvm::FoldingSetNodeID profile;
+  SymbolMetadata::Profile(profile, R, S, T, Count, SymbolTag);
+  void* InsertPos;
+  SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
+  if (!SD) {
+    SD = (SymExpr*) BPAlloc.Allocate<SymbolMetadata>();
+    new (SD) SymbolMetadata(SymbolCounter, R, S, T, Count, SymbolTag);
+    DataSet.InsertNode(SD, InsertPos);
+    ++SymbolCounter;
+  }
+
+  return cast<SymbolMetadata>(SD);
+}
+
+const SymIntExpr *SymbolManager::getSymIntExpr(const SymExpr *lhs,
+                                               BinaryOperator::Opcode op,
+                                               const llvm::APSInt& v,
+                                               QualType t) {
+  llvm::FoldingSetNodeID ID;
+  SymIntExpr::Profile(ID, lhs, op, v, t);
+  void *InsertPos;
+  SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
+
+  if (!data) {
+    data = (SymIntExpr*) BPAlloc.Allocate<SymIntExpr>();
+    new (data) SymIntExpr(lhs, op, v, t);
+    DataSet.InsertNode(data, InsertPos);
+  }
+
+  return cast<SymIntExpr>(data);
+}
+
+const SymSymExpr *SymbolManager::getSymSymExpr(const SymExpr *lhs,
+                                               BinaryOperator::Opcode op,
+                                               const SymExpr *rhs,
+                                               QualType t) {
+  llvm::FoldingSetNodeID ID;
+  SymSymExpr::Profile(ID, lhs, op, rhs, t);
+  void *InsertPos;
+  SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
+
+  if (!data) {
+    data = (SymSymExpr*) BPAlloc.Allocate<SymSymExpr>();
+    new (data) SymSymExpr(lhs, op, rhs, t);
+    DataSet.InsertNode(data, InsertPos);
+  }
+
+  return cast<SymSymExpr>(data);
+}
+
+QualType SymbolConjured::getType(ASTContext&) const {
+  return T;
+}
+
+QualType SymbolDerived::getType(ASTContext& Ctx) const {
+  return R->getValueType();
+}
+
+QualType SymbolExtent::getType(ASTContext& Ctx) const {
+  return Ctx.getSizeType();
+}
+
+QualType SymbolMetadata::getType(ASTContext&) const {
+  return T;
+}
+
+QualType SymbolRegionValue::getType(ASTContext& C) const {
+  return R->getValueType();
+}
+
+SymbolManager::~SymbolManager() {}
+
+bool SymbolManager::canSymbolicate(QualType T) {
+  T = T.getCanonicalType();
+
+  if (Loc::isLocType(T))
+    return true;
+
+  if (T->isIntegerType())
+    return T->isScalarType();
+
+  if (T->isRecordType() && !T->isUnionType())
+    return true;
+
+  return false;
+}
+
+void SymbolReaper::markLive(SymbolRef sym) {
+  TheLiving.insert(sym);
+  TheDead.erase(sym);
+}
+
+void SymbolReaper::markInUse(SymbolRef sym) {
+  if (isa<SymbolMetadata>(sym))
+    MetadataInUse.insert(sym);
+}
+
+bool SymbolReaper::maybeDead(SymbolRef sym) {
+  if (isLive(sym))
+    return false;
+
+  TheDead.insert(sym);
+  return true;
+}
+
+static bool IsLiveRegion(SymbolReaper &Reaper, const MemRegion *MR) {
+  MR = MR->getBaseRegion();
+
+  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(MR))
+    return Reaper.isLive(SR->getSymbol());
+
+  if (const VarRegion *VR = dyn_cast<VarRegion>(MR))
+    return Reaper.isLive(VR);
+
+  // FIXME: This is a gross over-approximation. What we really need is a way to
+  // tell if anything still refers to this region. Unlike SymbolicRegions,
+  // AllocaRegions don't have associated symbols, though, so we don't actually
+  // have a way to track their liveness.
+  if (isa<AllocaRegion>(MR))
+    return true;
+
+  if (isa<CXXThisRegion>(MR))
+    return true;
+
+  if (isa<MemSpaceRegion>(MR))
+    return true;
+
+  return false;
+}
+
+bool SymbolReaper::isLive(SymbolRef sym) {
+  if (TheLiving.count(sym))
+    return true;
+
+  if (const SymbolDerived *derived = dyn_cast<SymbolDerived>(sym)) {
+    if (isLive(derived->getParentSymbol())) {
+      markLive(sym);
+      return true;
+    }
+    return false;
+  }
+
+  if (const SymbolExtent *extent = dyn_cast<SymbolExtent>(sym)) {
+    if (IsLiveRegion(*this, extent->getRegion())) {
+      markLive(sym);
+      return true;
+    }
+    return false;
+  }
+
+  if (const SymbolMetadata *metadata = dyn_cast<SymbolMetadata>(sym)) {
+    if (MetadataInUse.count(sym)) {
+      if (IsLiveRegion(*this, metadata->getRegion())) {
+        markLive(sym);
+        MetadataInUse.erase(sym);
+        return true;
+      }
+    }
+    return false;
+  }
+
+  // Interogate the symbol.  It may derive from an input value to
+  // the analyzed function/method.
+  return isa<SymbolRegionValue>(sym);
+}
+
+bool SymbolReaper::isLive(const Stmt* ExprVal) const {
+  return LCtx->getAnalysisContext()->getRelaxedLiveVariables()->
+      isLive(Loc, ExprVal);
+}
+
+bool SymbolReaper::isLive(const VarRegion *VR) const {
+  const StackFrameContext *VarContext = VR->getStackFrame();
+  const StackFrameContext *CurrentContext = LCtx->getCurrentStackFrame();
+
+  if (VarContext == CurrentContext)
+    return LCtx->getAnalysisContext()->getRelaxedLiveVariables()->
+        isLive(Loc, VR->getDecl());
+
+  return VarContext->isParentOf(CurrentContext);
+}
+
+SymbolVisitor::~SymbolVisitor() {}