Pull ScopeInfo implementation into its own file.

The infrastructure for -Warc-repeated-use-of-weak got a little too heavy
to leave sitting at the top of Sema.cpp.

No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@164856 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 181 insertions, 0 deletions

diff --git a/lib/Sema/ScopeInfo.cpp b/lib/Sema/ScopeInfo.cpp
new file mode 100644
index 0000000000..bb9420d1e7
--- /dev/null
+++ b/lib/Sema/ScopeInfo.cpp
@@ -0,0 +1,181 @@
+//===--- ScopeInfo.cpp - Information about a semantic context -------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements FunctionScopeInfo and its subclasses, which contain
+// information about a single function, block, lambda, or method body.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Sema/ScopeInfo.h"
+#include "clang/AST/Decl.h"
+#include "clang/AST/DeclObjC.h"
+#include "clang/AST/Expr.h"
+#include "clang/AST/ExprCXX.h"
+#include "clang/AST/ExprObjC.h"
+
+using namespace clang;
+using namespace sema;
+
+void FunctionScopeInfo::Clear() {
+  HasBranchProtectedScope = false;
+  HasBranchIntoScope = false;
+  HasIndirectGoto = false;
+
+  SwitchStack.clear();
+  Returns.clear();
+  ErrorTrap.reset();
+  PossiblyUnreachableDiags.clear();
+  WeakObjectUses.clear();
+}
+
+static const NamedDecl *getBestPropertyDecl(const ObjCPropertyRefExpr *PropE) {
+  if (PropE->isExplicitProperty())
+    return PropE->getExplicitProperty();
+
+  return PropE->getImplicitPropertyGetter();
+}
+
+static bool isSelfExpr(const Expr *E) {
+  E = E->IgnoreParenImpCasts();
+
+  const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E);
+  if (!DRE)
+    return false;
+
+  const ImplicitParamDecl *Param = dyn_cast<ImplicitParamDecl>(DRE->getDecl());
+  if (!Param)
+    return false;
+
+  const ObjCMethodDecl *M = dyn_cast<ObjCMethodDecl>(Param->getDeclContext());
+  if (!M)
+    return false;
+
+  return M->getSelfDecl() == Param;
+}
+
+FunctionScopeInfo::WeakObjectProfileTy::BaseInfoTy
+FunctionScopeInfo::WeakObjectProfileTy::getBaseInfo(const Expr *E) {
+  E = E->IgnoreParenCasts();
+
+  const NamedDecl *D = 0;
+  bool IsExact = false;
+
+  switch (E->getStmtClass()) {
+  case Stmt::DeclRefExprClass:
+    D = cast<DeclRefExpr>(E)->getDecl();
+    IsExact = isa<VarDecl>(D);
+    break;
+  case Stmt::MemberExprClass: {
+    const MemberExpr *ME = cast<MemberExpr>(E);
+    D = ME->getMemberDecl();
+    IsExact = isa<CXXThisExpr>(ME->getBase()->IgnoreParenImpCasts());
+    break;
+  }
+  case Stmt::ObjCIvarRefExprClass: {
+    const ObjCIvarRefExpr *IE = cast<ObjCIvarRefExpr>(E);
+    D = IE->getDecl();
+    IsExact = isSelfExpr(IE->getBase());
+    break;
+  }
+  case Stmt::PseudoObjectExprClass: {
+    const PseudoObjectExpr *POE = cast<PseudoObjectExpr>(E);
+    const ObjCPropertyRefExpr *BaseProp =
+      dyn_cast<ObjCPropertyRefExpr>(POE->getSyntacticForm());
+    if (BaseProp) {
+      D = getBestPropertyDecl(BaseProp);
+
+      const Expr *DoubleBase = BaseProp->getBase();
+      if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(DoubleBase))
+        DoubleBase = OVE->getSourceExpr();
+
+      IsExact = isSelfExpr(DoubleBase);
+    }
+    break;
+  }
+  default:
+    break;
+  }
+
+  return BaseInfoTy(D, IsExact);
+}
+
+
+FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
+                                          const ObjCPropertyRefExpr *PropE)
+    : Base(0, true), Property(getBestPropertyDecl(PropE)) {
+
+  if (PropE->isObjectReceiver()) {
+    const OpaqueValueExpr *OVE = cast<OpaqueValueExpr>(PropE->getBase());
+    const Expr *E = OVE->getSourceExpr();
+    Base = getBaseInfo(E);
+  } else if (PropE->isClassReceiver()) {
+    Base.setPointer(PropE->getClassReceiver());
+  } else {
+    assert(PropE->isSuperReceiver());
+  }
+}
+
+FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
+                                                      const DeclRefExpr *DRE)
+  : Base(0, true), Property(DRE->getDecl()) {
+  assert(isa<VarDecl>(Property));
+}
+
+FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
+                                                  const ObjCIvarRefExpr *IvarE)
+  : Base(getBaseInfo(IvarE->getBase())), Property(IvarE->getDecl()) {
+}
+
+void FunctionScopeInfo::markSafeWeakUse(const Expr *E) {
+  E = E->IgnoreParenImpCasts();
+
+  if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) {
+    markSafeWeakUse(POE->getSyntacticForm());
+    return;
+  }
+
+  if (const ConditionalOperator *Cond = dyn_cast<ConditionalOperator>(E)) {
+    markSafeWeakUse(Cond->getTrueExpr());
+    markSafeWeakUse(Cond->getFalseExpr());
+    return;
+  }
+
+  if (const BinaryConditionalOperator *Cond =
+        dyn_cast<BinaryConditionalOperator>(E)) {
+    markSafeWeakUse(Cond->getCommon());
+    markSafeWeakUse(Cond->getFalseExpr());
+    return;
+  }
+
+  // Has this weak object been seen before?
+  FunctionScopeInfo::WeakObjectUseMap::iterator Uses;
+  if (const ObjCPropertyRefExpr *RefExpr = dyn_cast<ObjCPropertyRefExpr>(E))
+    Uses = WeakObjectUses.find(FunctionScopeInfo::WeakObjectProfileTy(RefExpr));
+  else if (const ObjCIvarRefExpr *IvarE = dyn_cast<ObjCIvarRefExpr>(E))
+    Uses = WeakObjectUses.find(FunctionScopeInfo::WeakObjectProfileTy(IvarE));
+  else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
+    Uses = WeakObjectUses.find(FunctionScopeInfo::WeakObjectProfileTy(DRE));
+  else
+    return;
+
+  if (Uses == WeakObjectUses.end())
+    return;
+
+  // Has there been a read from the object using this Expr?
+  FunctionScopeInfo::WeakUseVector::reverse_iterator ThisUse =
+    std::find(Uses->second.rbegin(), Uses->second.rend(), WeakUseTy(E, true));
+  if (ThisUse == Uses->second.rend())
+    return;
+
+  ThisUse->markSafe();
+}
+
+FunctionScopeInfo::~FunctionScopeInfo() { }
+BlockScopeInfo::~BlockScopeInfo() { }
+LambdaScopeInfo::~LambdaScopeInfo() { }