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[clangd] Factor out some helper functions related to heuristic resolution in TargetFinder 

Summary:
Two helpers are introduced:

 * Some of the logic previously in TargetFinder::Visit*() methods is
   factored out into resolveDependentExprToDecls().

 * Some of the logic in getMembersReferencedViaDependentName() is
   factored out into resolveTypeToRecordDecl().

D82739 will build on this and use these functions in new ways.

Reviewers: hokein

Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, kadircet, usaxena95, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D83371
This commit is contained in:
Nathan Ridge 2020-07-08 02:43:38 -04:00
parent e71c7b593a
commit 98d763ad05
1 changed files with 52 additions and 29 deletions
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81
clang-tools-extra/clangd/FindTarget.cpp
View File

@ -58,6 +58,24 @@ nodeToString(const ast_type_traits::DynTypedNode &N) {
return S;
}
// Helper function for getMembersReferencedViaDependentName()
// which takes a dependent type `T` and heuristically
// resolves it to a CXXRecordDecl in which we can try name lookup.
CXXRecordDecl *resolveTypeToRecordDecl(const Type *T) {
assert(T);
if (const auto *ICNT = T->getAs<InjectedClassNameType>()) {
T = ICNT->getInjectedSpecializationType().getTypePtrOrNull();
}
const auto *TST = T->getAs<TemplateSpecializationType>();
if (!TST)
return nullptr;
const ClassTemplateDecl *TD = dyn_cast_or_null<ClassTemplateDecl>(
TST->getTemplateName().getAsTemplateDecl());
if (!TD)
return nullptr;
return TD->getTemplatedDecl();
}
// Given a dependent type and a member name, heuristically resolve the
// name to one or more declarations.
// The current heuristic is simply to look up the name in the primary
@ -82,25 +100,17 @@ std::vector<const NamedDecl *> getMembersReferencedViaDependentName(
ET->getDecl()->lookup(NameFactory(ET->getDecl()->getASTContext()));
return {Result.begin(), Result.end()};
}
if (auto *ICNT = T->getAs<InjectedClassNameType>()) {
T = ICNT->getInjectedSpecializationType().getTypePtrOrNull();
if (auto *RD = resolveTypeToRecordDecl(T)) {
if (!RD->hasDefinition())
return {};
RD = RD->getDefinition();
DeclarationName Name = NameFactory(RD->getASTContext());
return RD->lookupDependentName(Name, [=](const NamedDecl *D) {
return IsNonstaticMember ? D->isCXXInstanceMember()
: !D->isCXXInstanceMember();
});
}
auto *TST = T->getAs<TemplateSpecializationType>();
if (!TST)
return {};
const ClassTemplateDecl *TD = dyn_cast_or_null<ClassTemplateDecl>(
TST->getTemplateName().getAsTemplateDecl());
if (!TD)
return {};
CXXRecordDecl *RD = TD->getTemplatedDecl();
if (!RD->hasDefinition())
return {};
RD = RD->getDefinition();
DeclarationName Name = NameFactory(RD->getASTContext());
return RD->lookupDependentName(Name, [=](const NamedDecl *D) {
return IsNonstaticMember ? D->isCXXInstanceMember()
: !D->isCXXInstanceMember();
});
return {};
}
// Given the type T of a dependent expression that appears of the LHS of a "->",
@ -144,6 +154,28 @@ const Type *getPointeeType(const Type *T) {
return FirstArg.getAsType().getTypePtrOrNull();
}
// Try to heuristically resolve a dependent expression `E` to one
// or more declarations that it likely references.
std::vector<const NamedDecl *> resolveDependentExprToDecls(const Expr *E) {
assert(E->isTypeDependent());
if (const auto *ME = dyn_cast<CXXDependentScopeMemberExpr>(E)) {
const Type *BaseType = ME->getBaseType().getTypePtrOrNull();
if (ME->isArrow()) {
BaseType = getPointeeType(BaseType);
}
return getMembersReferencedViaDependentName(
BaseType, [ME](ASTContext &) { return ME->getMember(); },
/*IsNonstaticMember=*/true);
}
if (const auto *RE = dyn_cast<DependentScopeDeclRefExpr>(E)) {
return getMembersReferencedViaDependentName(
RE->getQualifier()->getAsType(),
[RE](ASTContext &) { return RE->getDeclName(); },
/*IsNonstaticMember=*/false);
}
return {};
}
const NamedDecl *getTemplatePattern(const NamedDecl *D) {
if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(D)) {
if (const auto *Result = CRD->getTemplateInstantiationPattern())
@ -341,21 +373,12 @@ public:
}
void
VisitCXXDependentScopeMemberExpr(const CXXDependentScopeMemberExpr *E) {
const Type *BaseType = E->getBaseType().getTypePtrOrNull();
if (E->isArrow()) {
BaseType = getPointeeType(BaseType);
}
for (const NamedDecl *D : getMembersReferencedViaDependentName(
BaseType, [E](ASTContext &) { return E->getMember(); },
/*IsNonstaticMember=*/true)) {
for (const NamedDecl *D : resolveDependentExprToDecls(E)) {
Outer.add(D, Flags);
}
}
void VisitDependentScopeDeclRefExpr(const DependentScopeDeclRefExpr *E) {
for (const NamedDecl *D : getMembersReferencedViaDependentName(
E->getQualifier()->getAsType(),
[E](ASTContext &) { return E->getDeclName(); },
/*IsNonstaticMember=*/false)) {
for (const NamedDecl *D : resolveDependentExprToDecls(E)) {
Outer.add(D, Flags);
}
}