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When name lookup comes across a declaration that is in a module that 

is not visible, look for any previous declarations of that entity that
might be visible.

llvm-svn: 146563
This commit is contained in:
Douglas Gregor 2011-12-14 16:03:29 +00:00
parent 5533a55172
commit 4a814568b2
6 changed files with 116 additions and 29 deletions
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31
clang/include/clang/Sema/Lookup.h
View File

@ -266,23 +266,36 @@ public:
return Paths;
}
/// \brief Tests whether the given declaration is acceptable.
bool isAcceptableDecl(NamedDecl *D) const {
if (!D->isInIdentifierNamespace(IDNS))
return false;
/// \brief Determine whether the given declaration is visible to the
/// program.
static bool isVisible(NamedDecl *D) {
// So long as this declaration is not module-private or was parsed as
// part of this translation unit (i.e., in the module), we're allowed to
// find it.
// part of this translation unit (i.e., in the module), it's visible.
if (!D->isModulePrivate() || !D->isFromASTFile())
return true;
// FIXME: We should be allowed to refer to a module-private name from
// within the same module, e.g., during template instantiation.
// This requires us know which module a particular declaration came from.
return false;
}
/// \brief Retrieve the accepted (re)declaration of the given declaration,
/// if there is one.
NamedDecl *getAcceptableDecl(NamedDecl *D) const {
if (!D->isInIdentifierNamespace(IDNS))
return 0;
if (isVisible(D))
return D;
return getAcceptableDeclSlow(D);
}
private:
NamedDecl *getAcceptableDeclSlow(NamedDecl *D) const;
public:
/// \brief Returns the identifier namespace mask for this lookup.
unsigned getIdentifierNamespace() const {
return IDNS;

83
clang/lib/Sema/SemaLookup.cpp
View File

@ -321,6 +321,12 @@ void LookupResult::deletePaths(CXXBasePaths *Paths) {
delete Paths;
}
static NamedDecl *getVisibleDecl(NamedDecl *D);
NamedDecl *LookupResult::getAcceptableDeclSlow(NamedDecl *D) const {
return getVisibleDecl(D);
}
/// Resolves the result kind of this lookup.
void LookupResult::resolveKind() {
unsigned N = Decls.size();
@ -649,7 +655,7 @@ static bool LookupDirect(Sema &S, LookupResult &R, const DeclContext *DC) {
DeclContext::lookup_const_iterator I, E;
for (llvm::tie(I, E) = DC->lookup(R.getLookupName()); I != E; ++I) {
NamedDecl *D = *I;
if (R.isAcceptableDecl(D)) {
if ((D = R.getAcceptableDecl(D))) {
R.addDecl(D);
Found = true;
}
@ -875,9 +881,9 @@ bool Sema::CppLookupName(LookupResult &R, Scope *S) {
// Check whether the IdResolver has anything in this scope.
bool Found = false;
for (; I != IEnd && S->isDeclScope(*I); ++I) {
if (R.isAcceptableDecl(*I)) {
if (NamedDecl *ND = R.getAcceptableDecl(*I)) {
Found = true;
R.addDecl(*I);
R.addDecl(ND);
}
}
if (Found) {
@ -926,8 +932,8 @@ bool Sema::CppLookupName(LookupResult &R, Scope *S) {
if (ObjCIvarDecl *Ivar = Class->lookupInstanceVariable(
Name.getAsIdentifierInfo(),
ClassDeclared)) {
if (R.isAcceptableDecl(Ivar)) {
R.addDecl(Ivar);
if (NamedDecl *ND = R.getAcceptableDecl(Ivar)) {
R.addDecl(ND);
R.resolveKind();
return true;
}
@ -977,13 +983,13 @@ bool Sema::CppLookupName(LookupResult &R, Scope *S) {
// Check whether the IdResolver has anything in this scope.
bool Found = false;
for (; I != IEnd && S->isDeclScope(*I); ++I) {
if (R.isAcceptableDecl(*I)) {
if (NamedDecl *ND = R.getAcceptableDecl(*I)) {
// We found something. Look for anything else in our scope
// with this same name and in an acceptable identifier
// namespace, so that we can construct an overload set if we
// need to.
Found = true;
R.addDecl(*I);
R.addDecl(ND);
}
}
@ -1047,6 +1053,40 @@ bool Sema::CppLookupName(LookupResult &R, Scope *S) {
return !R.empty();
}
/// \brief Retrieve the previous declaration of D.
static NamedDecl *getPreviousDeclaration(NamedDecl *D) {
if (TagDecl *TD = dyn_cast<TagDecl>(D))
return TD->getPreviousDeclaration();
if (VarDecl *VD = dyn_cast<VarDecl>(D))
return VD->getPreviousDeclaration();
if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
return FD->getPreviousDeclaration();
if (RedeclarableTemplateDecl *RTD = dyn_cast<RedeclarableTemplateDecl>(D))
return RTD->getPreviousDeclaration();
return 0;
}
/// \brief Retrieve the visible declaration corresponding to D, if any.
///
/// This routine determines whether the declaration D is visible in the current
/// module, with the current imports. If not, it checks whether any
/// redeclaration of D is visible, and if so, returns that declaration.
///
/// \returns D, or a visible previous declaration of D, whichever is more recent
/// and visible. If no declaration of D is visible, returns null.
static NamedDecl *getVisibleDecl(NamedDecl *D) {
if (LookupResult::isVisible(D))
return D;
while ((D = getPreviousDeclaration(D))) {
if (LookupResult::isVisible(D))
return D;
}
return 0;
}
/// @brief Perform unqualified name lookup starting from a given
/// scope.
///
@ -1125,10 +1165,11 @@ bool Sema::LookupName(LookupResult &R, Scope *S, bool AllowBuiltinCreation) {
// If this declaration is module-private and it came from an AST
// file, we can't see it.
if ((*I)->isModulePrivate() && (*I)->isFromASTFile())
NamedDecl *D = getVisibleDecl(*I);
if (!D)
continue;
R.addDecl(*I);
R.addDecl(D);
if ((*I)->getAttr<OverloadableAttr>()) {
// If this declaration has the "overloadable" attribute, we
@ -1145,7 +1186,10 @@ bool Sema::LookupName(LookupResult &R, Scope *S, bool AllowBuiltinCreation) {
for (++LastI; LastI != IEnd; ++LastI) {
if (!S->isDeclScope(*LastI))
break;
R.addDecl(*LastI);
D = getVisibleDecl(*LastI);
if (D)
R.addDecl(D);
}
}
@ -2712,7 +2756,7 @@ static void LookupVisibleDecls(DeclContext *Ctx, LookupResult &Result,
DEnd = CurCtx->decls_end();
D != DEnd; ++D) {
if (NamedDecl *ND = dyn_cast<NamedDecl>(*D)) {
if (Result.isAcceptableDecl(ND)) {
if ((ND = Result.getAcceptableDecl(ND))) {
Consumer.FoundDecl(ND, Visited.checkHidden(ND), Ctx, InBaseClass);
Visited.add(ND);
}
@ -2723,17 +2767,16 @@ static void LookupVisibleDecls(DeclContext *Ctx, LookupResult &Result,
PEnd = ForwardProto->protocol_end();
P != PEnd;
++P) {
if (Result.isAcceptableDecl(*P)) {
Consumer.FoundDecl(*P, Visited.checkHidden(*P), Ctx, InBaseClass);
Visited.add(*P);
if (NamedDecl *ND = Result.getAcceptableDecl(*P)) {
Consumer.FoundDecl(ND, Visited.checkHidden(ND), Ctx, InBaseClass);
Visited.add(ND);
}
}
} else if (ObjCClassDecl *Class = dyn_cast<ObjCClassDecl>(*D)) {
ObjCInterfaceDecl *IFace = Class->getForwardInterfaceDecl();
if (Result.isAcceptableDecl(IFace)) {
Consumer.FoundDecl(IFace, Visited.checkHidden(IFace), Ctx,
InBaseClass);
Visited.add(IFace);
if (NamedDecl *ND = Result.getAcceptableDecl(IFace)) {
Consumer.FoundDecl(ND, Visited.checkHidden(ND), Ctx, InBaseClass);
Visited.add(ND);
}
}
@ -2873,7 +2916,7 @@ static void LookupVisibleDecls(Scope *S, LookupResult &Result,
for (Scope::decl_iterator D = S->decl_begin(), DEnd = S->decl_end();
D != DEnd; ++D) {
if (NamedDecl *ND = dyn_cast<NamedDecl>(*D))
if (Result.isAcceptableDecl(ND)) {
if ((ND = Result.getAcceptableDecl(ND))) {
Consumer.FoundDecl(ND, Visited.checkHidden(ND), 0, false);
Visited.add(ND);
}

2
clang/test/Modules/Inputs/decl.h Normal file
View File

@ -0,0 +1,2 @@
@class A;
typedef struct B B;

7
clang/test/Modules/Inputs/def.h Normal file
View File

@ -0,0 +1,7 @@
@interface A
@end
struct B {
int b1;
};

5
clang/test/Modules/Inputs/module.map
View File

@ -36,3 +36,8 @@ module category_bottom {
module redeclarations_left { header "redeclarations_left.h" }
module redeclarations_right { header "redeclarations_right.h" }
module load_failure { header "load_failure.h" }
module decldef {
explicit module Decl { header "decl.h" }
explicit module Def { header "def.h" }
}

17
clang/test/Modules/decldef.mm Normal file
View File

@ -0,0 +1,17 @@
// RUN: rm -rf %t
// RUN: %clang_cc1 -I %S/Inputs -fmodule-cache-path %t %s -verify
__import_module__ decldef;
A *a1; // expected-error{{unknown type name 'A'}}
B *b1; // expected-error{{unknown type name 'B'}}
__import_module__ decldef.Decl;
// FIXME: No link between @interface (which we can't see) and @class
// (which we can).
// A *a2;
B *b;
void testB() {
B b; // FIXME: Should error, because we can't see the definition.
}