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Implement elementary access control. 

llvm-svn: 94268
This commit is contained in:
John McCall 2010-01-23 00:46:32 +00:00
parent 86c1181c3d
commit 553c0796ee
13 changed files with 368 additions and 31 deletions
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15
clang/include/clang/AST/CXXInheritance.h
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@ -65,12 +65,21 @@ struct CXXBasePathElement {
/// subobject is being used.
class CXXBasePath : public llvm::SmallVector<CXXBasePathElement, 4> {
public:
/// \brief The access along this inheritance path.
CXXBasePath() : Access(AS_public) {}
/// \brief The access along this inheritance path. This is only
/// calculated when recording paths. AS_none is a special value
/// used to indicate a path which permits no legal access.
AccessSpecifier Access;
/// \brief The set of declarations found inside this base class
/// subobject.
DeclContext::lookup_result Decls;
void clear() {
llvm::SmallVectorImpl<CXXBasePathElement>::clear();
Access = AS_public;
}
};
/// BasePaths - Represents the set of paths from a derived class to
@ -138,10 +147,6 @@ class CXXBasePaths {
/// to help build the set of paths.
CXXBasePath ScratchPath;
/// ScratchAccess - A stack of accessibility annotations used by
/// Sema::lookupInBases.
llvm::SmallVector<AccessSpecifier, 4> ScratchAccess;
/// DetectedVirtual - The base class that is virtual.
const RecordType *DetectedVirtual;

9
clang/include/clang/AST/DeclCXX.h
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@ -817,6 +817,15 @@ public:
/// GraphViz.
void viewInheritance(ASTContext& Context) const;
/// MergeAccess - Calculates the access of a decl that is reached
/// along a path.
static AccessSpecifier MergeAccess(AccessSpecifier PathAccess,
AccessSpecifier DeclAccess) {
assert(DeclAccess != AS_none);
if (DeclAccess == AS_private) return AS_none;
return (PathAccess > DeclAccess ? PathAccess : DeclAccess);
}
static bool classof(const Decl *D) {
return D->getKind() == CXXRecord ||
D->getKind() == ClassTemplateSpecialization ||

9
clang/include/clang/Basic/DiagnosticSemaKinds.td
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@ -412,6 +412,15 @@ def err_class_redeclared_with_different_access : Error<
"%0 redeclared with '%1' access">;
def note_previous_access_declaration : Note<
"previously declared '%1' here">;
def err_access_outside_class : Error<
"access to %select{private|protected}0 member outside any class context">;
def note_access_natural : Note<"declared %select{private|protected}0 here">;
def note_access_constrained_by_path : Note<
"access to decl constrained by %select{private|protected}0 inheritance">;
def err_access_protected : Error<
"access to protected member of %0 from %1, which is not a subclass">;
def err_access_private : Error<
"access to private member of %0 from %1">;
// C++ name lookup
def err_incomplete_nested_name_spec : Error<

9
clang/include/clang/Basic/Specifiers.h
View File

@ -68,13 +68,14 @@ namespace clang {
bool ModeAttr : 1;
};
/// AccessSpecifier - A C++ access specifier (none, public, private,
/// protected).
/// AccessSpecifier - A C++ access specifier (public, private,
/// protected), plus the special value "none" which means
/// different things in different contexts.
enum AccessSpecifier {
AS_none,
AS_public,
AS_protected,
AS_private
AS_private,
AS_none
};
}

42
clang/lib/AST/CXXInheritance.cpp
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@ -61,7 +61,6 @@ void CXXBasePaths::clear() {
Paths.clear();
ClassSubobjects.clear();
ScratchPath.clear();
ScratchAccess.clear();
DetectedVirtual = 0;
}
@ -147,6 +146,10 @@ bool CXXRecordDecl::lookupInBases(BaseMatchesCallback *BaseMatches,
CXXBasePaths &Paths) const {
bool FoundPath = false;
// The access of the path down to this record.
AccessSpecifier AccessToHere = Paths.ScratchPath.Access;
bool IsFirstStep = Paths.ScratchPath.empty();
ASTContext &Context = getASTContext();
for (base_class_const_iterator BaseSpec = bases_begin(),
BaseSpecEnd = bases_end(); BaseSpec != BaseSpecEnd; ++BaseSpec) {
@ -191,20 +194,30 @@ bool CXXRecordDecl::lookupInBases(BaseMatchesCallback *BaseMatches,
Element.SubobjectNumber = Subobjects.second;
Paths.ScratchPath.push_back(Element);
// C++0x [class.access.base]p1 (paraphrased):
// The access of a member of a base class is the less permissive
// of its access within the base class and the access of the base
// class within the derived class.
// We're just calculating the access along the path, so we ignore
// the access specifiers of whatever decls we've found.
AccessSpecifier PathAccess = Paths.ScratchPath.Access;
Paths.ScratchAccess.push_back(PathAccess);
Paths.ScratchPath.Access
= std::max(PathAccess, BaseSpec->getAccessSpecifier());
// Calculate the "top-down" access to this base class.
// The spec actually describes this bottom-up, but top-down is
// equivalent because the definition works out as follows:
// 1. Write down the access along each step in the inheritance
// chain, followed by the access of the decl itself.
// For example, in
// class A { public: int foo; };
// class B : protected A {};
// class C : public B {};
// class D : private C {};
// we would write:
// private public protected public
// 2. If 'private' appears anywhere except far-left, access is denied.
// 3. Otherwise, overall access is determined by the most restrictive
// access in the sequence.
if (IsFirstStep)
Paths.ScratchPath.Access = BaseSpec->getAccessSpecifier();
else
Paths.ScratchPath.Access
= MergeAccess(AccessToHere, BaseSpec->getAccessSpecifier());
}
if (BaseMatches(BaseSpec, Paths.ScratchPath, UserData)) {
// We've found a path that terminates that this base.
// We've found a path that terminates at this base.
FoundPath = true;
if (Paths.isRecordingPaths()) {
// We have a path. Make a copy of it before moving on.
@ -237,8 +250,6 @@ bool CXXRecordDecl::lookupInBases(BaseMatchesCallback *BaseMatches,
// collecting paths).
if (Paths.isRecordingPaths()) {
Paths.ScratchPath.pop_back();
Paths.ScratchPath.Access = Paths.ScratchAccess.back();
Paths.ScratchAccess.pop_back();
}
// If we set a virtual earlier, and this isn't a path, forget it again.
@ -246,6 +257,9 @@ bool CXXRecordDecl::lookupInBases(BaseMatchesCallback *BaseMatches,
Paths.DetectedVirtual = 0;
}
}
// Reset the scratch path access.
Paths.ScratchPath.Access = AccessToHere;
return FoundPath;
}

2
clang/lib/Parse/ParseDeclCXX.cpp
View File

@ -983,7 +983,7 @@ Parser::BaseResult Parser::ParseBaseSpecifier(DeclPtrTy ClassDecl) {
// Parse an (optional) access specifier.
AccessSpecifier Access = getAccessSpecifierIfPresent();
if (Access)
if (Access != AS_none)
ConsumeToken();
// Parse the 'virtual' keyword (again!), in case it came after the

36
clang/lib/Sema/Lookup.h
View File

@ -131,6 +131,7 @@ public:
Sema::RedeclarationKind Redecl = Sema::NotForRedeclaration)
: ResultKind(NotFound),
Paths(0),
NamingClass(0),
SemaRef(SemaRef),
Name(Name),
NameLoc(NameLoc),
@ -150,6 +151,7 @@ public:
LookupResult(TemporaryToken _, const LookupResult &Other)
: ResultKind(NotFound),
Paths(0),
NamingClass(0),
SemaRef(Other.SemaRef),
Name(Other.Name),
NameLoc(Other.NameLoc),
@ -245,6 +247,37 @@ public:
return IDNS;
}
/// \brief Returns whether these results arose from performing a
/// lookup into a class.
bool isClassLookup() const {
return NamingClass != 0;
}
/// \brief Returns the 'naming class' for this lookup, i.e. the
/// class which was looked into to find these results.
///
/// C++0x [class.access.base]p5:
/// The access to a member is affected by the class in which the
/// member is named. This naming class is the class in which the
/// member name was looked up and found. [Note: this class can be
/// explicit, e.g., when a qualified-id is used, or implicit,
/// e.g., when a class member access operator (5.2.5) is used
/// (including cases where an implicit "this->" is added). If both
/// a class member access operator and a qualified-id are used to
/// name the member (as in p->T::m), the class naming the member
/// is the class named by the nested-name-specifier of the
/// qualified-id (that is, T). -- end note ]
///
/// This is set by the lookup routines when they find results in a class.
CXXRecordDecl *getNamingClass() const {
return NamingClass;
}
/// \brief Sets the 'naming class' for this lookup.
void setNamingClass(CXXRecordDecl *Record) {
NamingClass = Record;
}
/// \brief Add a declaration to these results with its natural access.
/// Does not test the acceptance criteria.
void addDecl(NamedDecl *D) {
@ -465,6 +498,8 @@ private:
void diagnose() {
if (isAmbiguous())
SemaRef.DiagnoseAmbiguousLookup(*this);
else if (isClassLookup() && SemaRef.getLangOptions().AccessControl)
SemaRef.CheckAccess(*this);
}
void setAmbiguous(AmbiguityKind AK) {
@ -504,6 +539,7 @@ private:
AmbiguityKind Ambiguity; // ill-defined unless ambiguous
UnresolvedSet<8> Decls;
CXXBasePaths *Paths;
CXXRecordDecl *NamingClass;
// Parameters.
Sema &SemaRef;

3
clang/lib/Sema/Sema.h
View File

@ -2361,6 +2361,9 @@ public:
CXXBasePaths &Paths,
bool NoPrivileges = false);
void CheckAccess(const LookupResult &R);
bool CheckAccess(const LookupResult &R, NamedDecl *D, AccessSpecifier Access);
bool CheckBaseClassAccess(QualType Derived, QualType Base,
unsigned InaccessibleBaseID,
CXXBasePaths& Paths, SourceLocation AccessLoc,

99
clang/lib/Sema/SemaAccess.cpp
View File

@ -12,6 +12,7 @@
//===----------------------------------------------------------------------===//
#include "Sema.h"
#include "Lookup.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/DeclCXX.h"
@ -137,3 +138,101 @@ bool Sema::CheckBaseClassAccess(QualType Derived, QualType Base,
return false;
}
/// Diagnose the path which caused the given declaration to become
/// inaccessible.
static void DiagnoseAccessPath(Sema &S, const LookupResult &R, NamedDecl *D,
AccessSpecifier Access) {
// Easy case: the decl's natural access determined its path access.
if (Access == D->getAccess() || D->getAccess() == AS_private) {
S.Diag(D->getLocation(), diag::note_access_natural)
<< (unsigned) (Access == AS_protected);
return;
}
// TODO: flesh this out
S.Diag(D->getLocation(), diag::note_access_constrained_by_path)
<< (unsigned) (Access == AS_protected);
}
/// Checks access to the given declaration in the current context.
///
/// \param R the means via which the access was made; must have a naming
/// class set
/// \param D the declaration accessed
/// \param Access the best access along any inheritance path from the
/// naming class to the declaration. AS_none means the path is impossible
bool Sema::CheckAccess(const LookupResult &R, NamedDecl *D,
AccessSpecifier Access) {
assert(R.getNamingClass() && "performing access check without naming class");
// If the access path is public, it's accessible everywhere.
if (Access == AS_public)
return false;
// Otherwise, derive the current class context.
DeclContext *DC = CurContext;
while (isa<CXXRecordDecl>(DC) &&
cast<CXXRecordDecl>(DC)->isAnonymousStructOrUnion())
DC = DC->getParent();
CXXRecordDecl *CurRecord;
if (isa<CXXRecordDecl>(DC))
CurRecord = cast<CXXRecordDecl>(DC);
else if (isa<CXXMethodDecl>(DC))
CurRecord = cast<CXXMethodDecl>(DC)->getParent();
else {
Diag(R.getNameLoc(), diag::err_access_outside_class)
<< (Access == AS_protected);
DiagnoseAccessPath(*this, R, D, Access);
return true;
}
CXXRecordDecl *NamingClass = R.getNamingClass();
while (NamingClass->isAnonymousStructOrUnion())
// This should be guaranteed by the fact that the decl has
// non-public access. If not, we should make it guaranteed!
NamingClass = cast<CXXRecordDecl>(NamingClass);
// White-list accesses from within the declaring class.
if (Access != AS_none &&
CurRecord->getCanonicalDecl() == NamingClass->getCanonicalDecl())
return false;
// Protected access.
if (Access == AS_protected) {
// FIXME: implement [class.protected]p1
if (CurRecord->isDerivedFrom(NamingClass))
return false;
// FIXME: dependent classes
}
// FIXME: friends
// Okay, it's a bad access, reject it.
CXXRecordDecl *DeclaringClass = cast<CXXRecordDecl>(D->getDeclContext());
if (Access == AS_protected) {
Diag(R.getNameLoc(), diag::err_access_protected)
<< Context.getTypeDeclType(DeclaringClass)
<< Context.getTypeDeclType(CurRecord);
DiagnoseAccessPath(*this, R, D, Access);
return true;
}
assert(Access == AS_private || Access == AS_none);
Diag(R.getNameLoc(), diag::err_access_private)
<< Context.getTypeDeclType(DeclaringClass)
<< Context.getTypeDeclType(CurRecord);
DiagnoseAccessPath(*this, R, D, Access);
return true;
}
/// Checks access to all the declarations in the given result set.
void Sema::CheckAccess(const LookupResult &R) {
for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I)
CheckAccess(R, *I, I.getAccess());
}

4
clang/lib/Sema/SemaDecl.cpp
View File

@ -5732,8 +5732,10 @@ Sema::DeclPtrTy Sema::ActOnEnumConstant(Scope *S, DeclPtrTy theEnumDecl,
IdLoc, Id, Owned(Val));
// Register this decl in the current scope stack.
if (New)
if (New) {
New->setAccess(TheEnumDecl->getAccess());
PushOnScopeChains(New, S);
}
return DeclPtrTy::make(New);
}

12
clang/lib/Sema/SemaLookup.cpp
View File

@ -967,6 +967,8 @@ bool Sema::LookupQualifiedName(LookupResult &R, DeclContext *LookupCtx,
// Perform qualified name lookup into the LookupCtx.
if (LookupDirect(R, LookupCtx)) {
R.resolveKind();
if (isa<CXXRecordDecl>(LookupCtx))
R.setNamingClass(cast<CXXRecordDecl>(LookupCtx));
return true;
}
@ -1039,6 +1041,8 @@ bool Sema::LookupQualifiedName(LookupResult &R, DeclContext *LookupCtx,
R.getLookupName().getAsOpaquePtr(), Paths))
return false;
R.setNamingClass(LookupRec);
// C++ [class.member.lookup]p2:
// [...] If the resulting set of declarations are not all from
// sub-objects of the same type, or the set has a nonstatic member
@ -1111,8 +1115,12 @@ bool Sema::LookupQualifiedName(LookupResult &R, DeclContext *LookupCtx,
// Lookup in a base class succeeded; return these results.
DeclContext::lookup_iterator I, E;
for (llvm::tie(I,E) = Paths.front().Decls; I != E; ++I)
R.addDecl(*I, std::max(SubobjectAccess, (*I)->getAccess()));
for (llvm::tie(I,E) = Paths.front().Decls; I != E; ++I) {
NamedDecl *D = *I;
AccessSpecifier AS = CXXRecordDecl::MergeAccess(SubobjectAccess,
D->getAccess());
R.addDecl(D, AS);
}
R.resolveKind();
return true;
}

152
clang/test/CXX/class.access/class.access.base/p1.cpp Normal file
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@ -0,0 +1,152 @@
// RUN: %clang_cc1 -fsyntax-only -faccess-control -verify %s
// C++0x [class.access.base]p1(a):
// If a class is declared to be a base class for another class using
// the public access specifier, the public members of the base class
// are accessible as public members of the derived class and protected
// members of the base class are accessible as protected members of
// the derived class.
namespace test0 {
class Base {
public: int pub; static int spub;
protected: int prot; static int sprot; // expected-note 4 {{declared protected here}}
private: int priv; static int spriv; // expected-note 8 {{declared private here}}
};
class Test : public Base {
void test() {
pub++;
spub++;
prot++;
sprot++;
priv++; // expected-error {{private member}}
spriv++; // expected-error {{private member}}
Base::pub++;
Base::spub++;
Base::prot++;
Base::sprot++;
Base::priv++; // expected-error {{private member}}
Base::spriv++; // expected-error {{private member}}
}
};
void test(Test *t) {
t->pub++;
t->spub++;
t->prot++; // expected-error {{protected member}}
t->sprot++; // expected-error {{protected member}}
t->priv++; // expected-error {{private member}}
t->spriv++; // expected-error {{private member}}
t->Base::pub++;
t->Base::spub++;
t->Base::prot++; // expected-error {{protected member}}
t->Base::sprot++; // expected-error {{protected member}}
t->Base::priv++; // expected-error {{private member}}
t->Base::spriv++; // expected-error {{private member}}
}
}
// C++0x [class.access.base]p1(b):
// If a class is declared to be a base class for another class using
// the protected access specifier, the public and protected members
// of the base class are accessible as protected members of the
// derived class.
namespace test1 {
class Base { // expected-note 6 {{constrained by protected inheritance}}
public: int pub; static int spub; // expected-note 2 {{constrained by protected inheritance}}
protected: int prot; static int sprot; // expected-note 4 {{declared protected here}}
private: int priv; static int spriv; // expected-note 8 {{declared private here}}
};
class Test : protected Base {
void test() {
pub++;
spub++;
prot++;
sprot++;
priv++; // expected-error {{private member}}
spriv++; // expected-error {{private member}}
Base::pub++;
Base::spub++;
Base::prot++;
Base::sprot++;
Base::priv++; // expected-error {{private member}}
Base::spriv++; // expected-error {{private member}}
}
};
void test(Test *t) {
t->pub++; // expected-error {{protected member}}
t->spub++; // expected-error {{protected member}}
t->prot++; // expected-error {{protected member}}
t->sprot++; // expected-error {{protected member}}
t->priv++; // expected-error {{private member}}
t->spriv++; // expected-error {{private member}}
// Two possible errors here: one for Base, one for the member
t->Base::pub++; // expected-error {{protected member}}
t->Base::spub++; // expected-error {{protected member}}
t->Base::prot++; // expected-error 2 {{protected member}}
t->Base::sprot++; // expected-error 2 {{protected member}}
t->Base::priv++; // expected-error {{protected member}} expected-error {{private member}}
t->Base::spriv++; // expected-error {{protected member}} expected-error {{private member}}
}
}
// C++0x [class.access.base]p1(b):
// If a class is declared to be a base class for another class using
// the private access specifier, the public and protected members of
// the base class are accessible as private members of the derived
// class.
namespace test2 {
class Base { //expected-note 6 {{constrained by private inheritance}}
public:
int pub; // expected-note {{constrained by private inheritance}}
static int spub; // expected-note {{constrained by private inheritance}}
protected:
int prot; // expected-note {{constrained by private inheritance}} \
// expected-note {{declared protected here}}
static int sprot; // expected-note {{constrained by private inheritance}} \
// expected-note {{declared protected here}}
private:
int priv; // expected-note 4 {{declared private here}}
static int spriv; // expected-note 4 {{declared private here}}
};
class Test : private Base { // expected-note 6 {{'private' inheritance specifier here}}
void test() {
pub++;
spub++;
prot++;
sprot++;
priv++; // expected-error {{private member}}
spriv++; // expected-error {{private member}}
Base::pub++;
Base::spub++;
Base::prot++;
Base::sprot++;
Base::priv++; // expected-error {{private member}}
Base::spriv++; // expected-error {{private member}}
}
};
void test(Test *t) {
t->pub++; // expected-error {{private member}} expected-error {{inaccessible base class}}
t->spub++; // expected-error {{private member}}
t->prot++; // expected-error {{private member}} expected-error {{inaccessible base class}}
t->sprot++; // expected-error {{private member}}
t->priv++; // expected-error {{private member}} expected-error {{inaccessible base class}}
t->spriv++; // expected-error {{private member}}
t->Base::pub++; // expected-error {{private member}} expected-error {{inaccessible base class}}
t->Base::spub++; // expected-error {{private member}}
t->Base::prot++; // expected-error {{protected member}} expected-error {{private member}} expected-error {{inaccessible base class}}
t->Base::sprot++; // expected-error {{protected member}} expected-error {{private member}}
t->Base::priv++; // expected-error 2 {{private member}} expected-error {{inaccessible base class}}
t->Base::spriv++; // expected-error 2 {{private member}}
}
}

7
clang/test/SemaCXX/access-control-check.cpp
View File

@ -5,12 +5,11 @@ class M {
};
class P {
int iP;
int PPR();
int iP; // expected-note {{declared private here}}
int PPR(); // expected-note {{declared private here}}
};
class N : M,P {
N() {}
// FIXME. No access violation is reported in method call or member access.
int PR() { return iP + PPR(); }
int PR() { return iP + PPR(); } // expected-error 2 {{access to private member of 'class P'}}
};