TransBlockObjCVariable.cpp [plain text]
#include "Transforms.h"
#include "Internals.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Attr.h"
#include "clang/Basic/SourceManager.h"
using namespace clang;
using namespace arcmt;
using namespace trans;
namespace {
class RootBlockObjCVarRewriter :
public RecursiveASTVisitor<RootBlockObjCVarRewriter> {
llvm::DenseSet<VarDecl *> &VarsToChange;
class BlockVarChecker : public RecursiveASTVisitor<BlockVarChecker> {
VarDecl *Var;
typedef RecursiveASTVisitor<BlockVarChecker> base;
public:
BlockVarChecker(VarDecl *var) : Var(var) { }
bool TraverseImplicitCastExpr(ImplicitCastExpr *castE) {
if (DeclRefExpr *
ref = dyn_cast<DeclRefExpr>(castE->getSubExpr())) {
if (ref->getDecl() == Var) {
if (castE->getCastKind() == CK_LValueToRValue)
return true; if (castE->getCastKind() == CK_NoOp && castE->isLValue() &&
Var->getASTContext().getLangOpts().CPlusPlus)
return true; }
}
return base::TraverseImplicitCastExpr(castE);
}
bool VisitDeclRefExpr(DeclRefExpr *E) {
if (E->getDecl() == Var)
return false; return true;
}
};
public:
RootBlockObjCVarRewriter(llvm::DenseSet<VarDecl *> &VarsToChange)
: VarsToChange(VarsToChange) { }
bool VisitBlockDecl(BlockDecl *block) {
SmallVector<VarDecl *, 4> BlockVars;
for (const auto &I : block->captures()) {
VarDecl *var = I.getVariable();
if (I.isByRef() &&
var->getType()->isObjCObjectPointerType() &&
isImplicitStrong(var->getType())) {
BlockVars.push_back(var);
}
}
for (unsigned i = 0, e = BlockVars.size(); i != e; ++i) {
VarDecl *var = BlockVars[i];
BlockVarChecker checker(var);
bool onlyValueOfVarIsNeeded = checker.TraverseStmt(block->getBody());
if (onlyValueOfVarIsNeeded)
VarsToChange.insert(var);
else
VarsToChange.erase(var);
}
return true;
}
private:
bool isImplicitStrong(QualType ty) {
if (isa<AttributedType>(ty.getTypePtr()))
return false;
return ty.getLocalQualifiers().getObjCLifetime() == Qualifiers::OCL_Strong;
}
};
class BlockObjCVarRewriter : public RecursiveASTVisitor<BlockObjCVarRewriter> {
llvm::DenseSet<VarDecl *> &VarsToChange;
public:
BlockObjCVarRewriter(llvm::DenseSet<VarDecl *> &VarsToChange)
: VarsToChange(VarsToChange) { }
bool TraverseBlockDecl(BlockDecl *block) {
RootBlockObjCVarRewriter(VarsToChange).TraverseDecl(block);
return true;
}
};
}
void BlockObjCVariableTraverser::traverseBody(BodyContext &BodyCtx) {
MigrationPass &Pass = BodyCtx.getMigrationContext().Pass;
llvm::DenseSet<VarDecl *> VarsToChange;
BlockObjCVarRewriter trans(VarsToChange);
trans.TraverseStmt(BodyCtx.getTopStmt());
for (llvm::DenseSet<VarDecl *>::iterator
I = VarsToChange.begin(), E = VarsToChange.end(); I != E; ++I) {
VarDecl *var = *I;
BlocksAttr *attr = var->getAttr<BlocksAttr>();
if(!attr)
continue;
bool useWeak = canApplyWeak(Pass.Ctx, var->getType());
SourceManager &SM = Pass.Ctx.getSourceManager();
Transaction Trans(Pass.TA);
Pass.TA.replaceText(SM.getExpansionLoc(attr->getLocation()),
"__block",
useWeak ? "__weak" : "__unsafe_unretained");
}
}