Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

3 files changed, 481 insertions, 0 deletions

diff --git a/build/clang-plugin/mozsearch-plugin/from-clangd/HeuristicResolver.cpp b/build/clang-plugin/mozsearch-plugin/from-clangd/HeuristicResolver.cpp
new file mode 100644
index 0000000000..719094dbf2
--- /dev/null
+++ b/build/clang-plugin/mozsearch-plugin/from-clangd/HeuristicResolver.cpp
@@ -0,0 +1,349 @@
+//===--- HeuristicResolver.cpp ---------------------------*- C++-*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "HeuristicResolver.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/CXXInheritance.h"
+#include "clang/AST/DeclTemplate.h"
+#include "clang/AST/ExprCXX.h"
+#include "clang/AST/Type.h"
+
+namespace clang {
+namespace clangd {
+
+// Convenience lambdas for use as the 'Filter' parameter of
+// HeuristicResolver::resolveDependentMember().
+const auto NoFilter = [](const NamedDecl *D) { return true; };
+const auto NonStaticFilter = [](const NamedDecl *D) {
+  return D->isCXXInstanceMember();
+};
+const auto StaticFilter = [](const NamedDecl *D) {
+  return !D->isCXXInstanceMember();
+};
+const auto ValueFilter = [](const NamedDecl *D) { return isa<ValueDecl>(D); };
+const auto TypeFilter = [](const NamedDecl *D) { return isa<TypeDecl>(D); };
+const auto TemplateFilter = [](const NamedDecl *D) {
+  return isa<TemplateDecl>(D);
+};
+
+namespace {
+
+const Type *resolveDeclsToType(const std::vector<const NamedDecl *> &Decls,
+                               ASTContext &Ctx) {
+  if (Decls.size() != 1) // Names an overload set -- just bail.
+    return nullptr;
+  if (const auto *TD = dyn_cast<TypeDecl>(Decls[0])) {
+    return Ctx.getTypeDeclType(TD).getTypePtr();
+  }
+  if (const auto *VD = dyn_cast<ValueDecl>(Decls[0])) {
+    return VD->getType().getTypePtrOrNull();
+  }
+  return nullptr;
+}
+
+} // namespace
+
+// Helper function for HeuristicResolver::resolveDependentMember()
+// which takes a possibly-dependent type `T` and heuristically
+// resolves it to a CXXRecordDecl in which we can try name lookup.
+CXXRecordDecl *HeuristicResolver::resolveTypeToRecordDecl(const Type *T) const {
+  assert(T);
+
+  // Unwrap type sugar such as type aliases.
+  T = T->getCanonicalTypeInternal().getTypePtr();
+
+  if (const auto *DNT = T->getAs<DependentNameType>()) {
+    T = resolveDeclsToType(resolveDependentNameType(DNT), Ctx);
+    if (!T)
+      return nullptr;
+    T = T->getCanonicalTypeInternal().getTypePtr();
+  }
+
+  if (const auto *RT = T->getAs<RecordType>())
+    return dyn_cast<CXXRecordDecl>(RT->getDecl());
+
+  if (const auto *ICNT = T->getAs<InjectedClassNameType>())
+    T = ICNT->getInjectedSpecializationType().getTypePtrOrNull();
+  if (!T)
+    return nullptr;
+
+  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();
+}
+
+const Type *HeuristicResolver::getPointeeType(const Type *T) const {
+  if (!T)
+    return nullptr;
+
+  if (T->isPointerType())
+    return T->castAs<PointerType>()->getPointeeType().getTypePtrOrNull();
+
+  // Try to handle smart pointer types.
+
+  // Look up operator-> in the primary template. If we find one, it's probably a
+  // smart pointer type.
+  auto ArrowOps = resolveDependentMember(
+      T, Ctx.DeclarationNames.getCXXOperatorName(OO_Arrow), NonStaticFilter);
+  if (ArrowOps.empty())
+    return nullptr;
+
+  // Getting the return type of the found operator-> method decl isn't useful,
+  // because we discarded template arguments to perform lookup in the primary
+  // template scope, so the return type would just have the form U* where U is a
+  // template parameter type.
+  // Instead, just handle the common case where the smart pointer type has the
+  // form of SmartPtr<X, ...>, and assume X is the pointee type.
+  auto *TST = T->getAs<TemplateSpecializationType>();
+  if (!TST)
+    return nullptr;
+  if (TST->template_arguments().size() == 0)
+    return nullptr;
+  const TemplateArgument &FirstArg = TST->template_arguments()[0];
+  if (FirstArg.getKind() != TemplateArgument::Type)
+    return nullptr;
+  return FirstArg.getAsType().getTypePtrOrNull();
+}
+
+std::vector<const NamedDecl *> HeuristicResolver::resolveMemberExpr(
+    const CXXDependentScopeMemberExpr *ME) const {
+  // If the expression has a qualifier, first try resolving the member
+  // inside the qualifier's type.
+  // Note that we cannot use a NonStaticFilter in either case, for a couple
+  // of reasons:
+  //   1. It's valid to access a static member using instance member syntax,
+  //      e.g. `instance.static_member`.
+  //   2. We can sometimes get a CXXDependentScopeMemberExpr for static
+  //      member syntax too, e.g. if `X::static_member` occurs inside
+  //      an instance method, it's represented as a CXXDependentScopeMemberExpr
+  //      with `this` as the base expression as `X` as the qualifier
+  //      (which could be valid if `X` names a base class after instantiation).
+  if (NestedNameSpecifier *NNS = ME->getQualifier()) {
+    if (const Type *QualifierType = resolveNestedNameSpecifierToType(NNS)) {
+      auto Decls =
+          resolveDependentMember(QualifierType, ME->getMember(), NoFilter);
+      if (!Decls.empty())
+        return Decls;
+    }
+  }
+
+  // If that didn't yield any results, try resolving the member inside
+  // the expression's base type.
+  const Type *BaseType = ME->getBaseType().getTypePtrOrNull();
+  if (ME->isArrow()) {
+    BaseType = getPointeeType(BaseType);
+  }
+  if (!BaseType)
+    return {};
+  if (const auto *BT = BaseType->getAs<BuiltinType>()) {
+    // If BaseType is the type of a dependent expression, it's just
+    // represented as BuiltinType::Dependent which gives us no information. We
+    // can get further by analyzing the dependent expression.
+    Expr *Base = ME->isImplicitAccess() ? nullptr : ME->getBase();
+    if (Base && BT->getKind() == BuiltinType::Dependent) {
+      BaseType = resolveExprToType(Base);
+    }
+  }
+  return resolveDependentMember(BaseType, ME->getMember(), NoFilter);
+}
+
+std::vector<const NamedDecl *> HeuristicResolver::resolveDeclRefExpr(
+    const DependentScopeDeclRefExpr *RE) const {
+  return resolveDependentMember(RE->getQualifier()->getAsType(),
+                                RE->getDeclName(), StaticFilter);
+}
+
+std::vector<const NamedDecl *>
+HeuristicResolver::resolveTypeOfCallExpr(const CallExpr *CE) const {
+  const auto *CalleeType = resolveExprToType(CE->getCallee());
+  if (!CalleeType)
+    return {};
+  if (const auto *FnTypePtr = CalleeType->getAs<PointerType>())
+    CalleeType = FnTypePtr->getPointeeType().getTypePtr();
+  if (const FunctionType *FnType = CalleeType->getAs<FunctionType>()) {
+    if (const auto *D =
+            resolveTypeToRecordDecl(FnType->getReturnType().getTypePtr())) {
+      return {D};
+    }
+  }
+  return {};
+}
+
+std::vector<const NamedDecl *>
+HeuristicResolver::resolveCalleeOfCallExpr(const CallExpr *CE) const {
+  if (const auto *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) {
+    return {ND};
+  }
+
+  return resolveExprToDecls(CE->getCallee());
+}
+
+std::vector<const NamedDecl *> HeuristicResolver::resolveUsingValueDecl(
+    const UnresolvedUsingValueDecl *UUVD) const {
+  return resolveDependentMember(UUVD->getQualifier()->getAsType(),
+                                UUVD->getNameInfo().getName(), ValueFilter);
+}
+
+std::vector<const NamedDecl *> HeuristicResolver::resolveDependentNameType(
+    const DependentNameType *DNT) const {
+  return resolveDependentMember(
+      resolveNestedNameSpecifierToType(DNT->getQualifier()),
+      DNT->getIdentifier(), TypeFilter);
+}
+
+std::vector<const NamedDecl *>
+HeuristicResolver::resolveTemplateSpecializationType(
+    const DependentTemplateSpecializationType *DTST) const {
+  return resolveDependentMember(
+      resolveNestedNameSpecifierToType(DTST->getQualifier()),
+      DTST->getIdentifier(), TemplateFilter);
+}
+
+std::vector<const NamedDecl *>
+HeuristicResolver::resolveExprToDecls(const Expr *E) const {
+  if (const auto *ME = dyn_cast<CXXDependentScopeMemberExpr>(E)) {
+    return resolveMemberExpr(ME);
+  }
+  if (const auto *RE = dyn_cast<DependentScopeDeclRefExpr>(E)) {
+    return resolveDeclRefExpr(RE);
+  }
+  if (const auto *OE = dyn_cast<OverloadExpr>(E)) {
+    return {OE->decls_begin(), OE->decls_end()};
+  }
+  if (const auto *CE = dyn_cast<CallExpr>(E)) {
+    return resolveTypeOfCallExpr(CE);
+  }
+  if (const auto *ME = dyn_cast<MemberExpr>(E))
+    return {ME->getMemberDecl()};
+
+  return {};
+}
+
+const Type *HeuristicResolver::resolveExprToType(const Expr *E) const {
+  std::vector<const NamedDecl *> Decls = resolveExprToDecls(E);
+  if (!Decls.empty())
+    return resolveDeclsToType(Decls, Ctx);
+
+  return E->getType().getTypePtr();
+}
+
+const Type *HeuristicResolver::resolveNestedNameSpecifierToType(
+    const NestedNameSpecifier *NNS) const {
+  if (!NNS)
+    return nullptr;
+
+  // The purpose of this function is to handle the dependent (Kind ==
+  // Identifier) case, but we need to recurse on the prefix because
+  // that may be dependent as well, so for convenience handle
+  // the TypeSpec cases too.
+  switch (NNS->getKind()) {
+  case NestedNameSpecifier::TypeSpec:
+  case NestedNameSpecifier::TypeSpecWithTemplate:
+    return NNS->getAsType();
+  case NestedNameSpecifier::Identifier: {
+    return resolveDeclsToType(
+        resolveDependentMember(
+            resolveNestedNameSpecifierToType(NNS->getPrefix()),
+            NNS->getAsIdentifier(), TypeFilter),
+        Ctx);
+  }
+  default:
+    break;
+  }
+  return nullptr;
+}
+
+namespace {
+
+bool isOrdinaryMember(const NamedDecl *ND) {
+  return ND->isInIdentifierNamespace(Decl::IDNS_Ordinary | Decl::IDNS_Tag |
+                                     Decl::IDNS_Member);
+}
+
+bool findOrdinaryMember(const CXXRecordDecl *RD, CXXBasePath &Path,
+                        DeclarationName Name) {
+  Path.Decls = RD->lookup(Name).begin();
+  for (DeclContext::lookup_iterator I = Path.Decls, E = I.end(); I != E; ++I)
+    if (isOrdinaryMember(*I))
+      return true;
+
+  return false;
+}
+
+} // namespace
+
+bool HeuristicResolver::findOrdinaryMemberInDependentClasses(
+    const CXXBaseSpecifier *Specifier, CXXBasePath &Path,
+    DeclarationName Name) const {
+  CXXRecordDecl *RD =
+      resolveTypeToRecordDecl(Specifier->getType().getTypePtr());
+  if (!RD)
+    return false;
+  return findOrdinaryMember(RD, Path, Name);
+}
+
+std::vector<const NamedDecl *> HeuristicResolver::lookupDependentName(
+    CXXRecordDecl *RD, DeclarationName Name,
+    llvm::function_ref<bool(const NamedDecl *ND)> Filter) const {
+  std::vector<const NamedDecl *> Results;
+
+  // Lookup in the class.
+  bool AnyOrdinaryMembers = false;
+  for (const NamedDecl *ND : RD->lookup(Name)) {
+    if (isOrdinaryMember(ND))
+      AnyOrdinaryMembers = true;
+    if (Filter(ND))
+      Results.push_back(ND);
+  }
+  if (AnyOrdinaryMembers)
+    return Results;
+
+  // Perform lookup into our base classes.
+  CXXBasePaths Paths;
+  Paths.setOrigin(RD);
+  if (!RD->lookupInBases(
+          [&](const CXXBaseSpecifier *Specifier, CXXBasePath &Path) {
+            return findOrdinaryMemberInDependentClasses(Specifier, Path, Name);
+          },
+          Paths, /*LookupInDependent=*/true))
+    return Results;
+  for (DeclContext::lookup_iterator I = Paths.front().Decls, E = I.end();
+       I != E; ++I) {
+    if (isOrdinaryMember(*I) && Filter(*I))
+      Results.push_back(*I);
+  }
+  return Results;
+}
+
+std::vector<const NamedDecl *> HeuristicResolver::resolveDependentMember(
+    const Type *T, DeclarationName Name,
+    llvm::function_ref<bool(const NamedDecl *ND)> Filter) const {
+  if (!T)
+    return {};
+  if (auto *ET = T->getAs<EnumType>()) {
+    auto Result = ET->getDecl()->lookup(Name);
+    return {Result.begin(), Result.end()};
+  }
+  if (auto *RD = resolveTypeToRecordDecl(T)) {
+    if (!RD->hasDefinition())
+      return {};
+    RD = RD->getDefinition();
+    return lookupDependentName(RD, Name, Filter);
+  }
+  return {};
+}
+
+} // namespace clangd
+} // namespace clang
diff --git a/build/clang-plugin/mozsearch-plugin/from-clangd/HeuristicResolver.h b/build/clang-plugin/mozsearch-plugin/from-clangd/HeuristicResolver.h
new file mode 100644
index 0000000000..dc04123d37
--- /dev/null
+++ b/build/clang-plugin/mozsearch-plugin/from-clangd/HeuristicResolver.h
@@ -0,0 +1,122 @@
+//===--- HeuristicResolver.h - Resolution of dependent names -----*- C++-*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_HEURISTICRESOLVER_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_HEURISTICRESOLVER_H
+
+#include "clang/AST/Decl.h"
+#include <vector>
+
+namespace clang {
+
+class ASTContext;
+class CallExpr;
+class CXXBasePath;
+class CXXDependentScopeMemberExpr;
+class DeclarationName;
+class DependentScopeDeclRefExpr;
+class NamedDecl;
+class Type;
+class UnresolvedUsingValueDecl;
+
+namespace clangd {
+
+// This class heuristic resolution of declarations and types in template code.
+//
+// As a compiler, clang only needs to perform certain types of processing on
+// template code (such as resolving dependent names to declarations, or
+// resolving the type of a dependent expression) after instantiation. Indeed,
+// C++ language features such as template specialization mean such resolution
+// cannot be done accurately before instantiation
+//
+// However, template code is written and read in uninstantiated form, and clangd
+// would like to provide editor features like go-to-definition in template code
+// where possible. To this end, clangd attempts to resolve declarations and
+// types in uninstantiated code by using heuristics, understanding that the
+// results may not be fully accurate but that this is better than nothing.
+//
+// At this time, the heuristic used is a simple but effective one: assume that
+// template instantiations are based on the primary template definition and not
+// not a specialization. More advanced heuristics may be added in the future.
+class HeuristicResolver {
+public:
+  HeuristicResolver(ASTContext &Ctx) : Ctx(Ctx) {}
+
+  // Try to heuristically resolve certain types of expressions, declarations, or
+  // types to one or more likely-referenced declarations.
+  std::vector<const NamedDecl *>
+  resolveMemberExpr(const CXXDependentScopeMemberExpr *ME) const;
+  std::vector<const NamedDecl *>
+  resolveDeclRefExpr(const DependentScopeDeclRefExpr *RE) const;
+  std::vector<const NamedDecl *>
+  resolveTypeOfCallExpr(const CallExpr *CE) const;
+  std::vector<const NamedDecl *>
+  resolveCalleeOfCallExpr(const CallExpr *CE) const;
+  std::vector<const NamedDecl *>
+  resolveUsingValueDecl(const UnresolvedUsingValueDecl *UUVD) const;
+  std::vector<const NamedDecl *>
+  resolveDependentNameType(const DependentNameType *DNT) const;
+  std::vector<const NamedDecl *> resolveTemplateSpecializationType(
+      const DependentTemplateSpecializationType *DTST) const;
+
+  // Try to heuristically resolve a dependent nested name specifier
+  // to the type it likely denotes. Note that *dependent* name specifiers always
+  // denote types, not namespaces.
+  const Type *
+  resolveNestedNameSpecifierToType(const NestedNameSpecifier *NNS) const;
+
+  // Given the type T of a dependent expression that appears of the LHS of a
+  // "->", heuristically find a corresponding pointee type in whose scope we
+  // could look up the name appearing on the RHS.
+  const Type *getPointeeType(const Type *T) const;
+
+private:
+  ASTContext &Ctx;
+
+  // Given a tag-decl 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
+  // template. This is a heuristic because the template could potentially
+  // have specializations that declare different members.
+  // Multiple declarations could be returned if the name is overloaded
+  // (e.g. an overloaded method in the primary template).
+  // This heuristic will give the desired answer in many cases, e.g.
+  // for a call to vector<T>::size().
+  std::vector<const NamedDecl *> resolveDependentMember(
+      const Type *T, DeclarationName Name,
+      llvm::function_ref<bool(const NamedDecl *ND)> Filter) const;
+
+  // Try to heuristically resolve the type of a possibly-dependent expression
+  // `E`.
+  const Type *resolveExprToType(const Expr *E) const;
+  std::vector<const NamedDecl *> resolveExprToDecls(const Expr *E) const;
+
+  // Helper function for HeuristicResolver::resolveDependentMember()
+  // which takes a possibly-dependent type `T` and heuristically
+  // resolves it to a CXXRecordDecl in which we can try name lookup.
+  CXXRecordDecl *resolveTypeToRecordDecl(const Type *T) const;
+
+  // This is a reimplementation of CXXRecordDecl::lookupDependentName()
+  // so that the implementation can call into other HeuristicResolver helpers.
+  // FIXME: Once HeuristicResolver is upstreamed to the clang libraries
+  // (https://github.com/clangd/clangd/discussions/1662),
+  // CXXRecordDecl::lookupDepenedentName() can be removed, and its call sites
+  // can be modified to benefit from the more comprehensive heuristics offered
+  // by HeuristicResolver instead.
+  std::vector<const NamedDecl *> lookupDependentName(
+      CXXRecordDecl *RD, DeclarationName Name,
+      llvm::function_ref<bool(const NamedDecl *ND)> Filter) const;
+  bool findOrdinaryMemberInDependentClasses(const CXXBaseSpecifier *Specifier,
+                                            CXXBasePath &Path,
+                                            DeclarationName Name) const;
+};
+
+} // namespace clangd
+} // namespace clang
+
+#endif
diff --git a/build/clang-plugin/mozsearch-plugin/from-clangd/README.md b/build/clang-plugin/mozsearch-plugin/from-clangd/README.md
new file mode 100644
index 0000000000..9f39dab231
--- /dev/null
+++ b/build/clang-plugin/mozsearch-plugin/from-clangd/README.md
@@ -0,0 +1,10 @@
+The facilities in this subdirectory are copied over from clangd
+(https://clangd.llvm.org/).
+
+The files here are currently copies of the following upstream files:
+https://github.com/llvm/llvm-project/blob/2bcbcbefcd0f7432f99cc07bb47d1e1ecb579a3f/clang-tools-extra/clangd/HeuristicResolver.h
+https://github.com/llvm/llvm-project/blob/2bcbcbefcd0f7432f99cc07bb47d1e1ecb579a3f/clang-tools-extra/clangd/HeuristicResolver.cpp
+
+If, in the future, these facilities are moved from clangd to
+to libclangTooling and exposed in the clang API headers, we can
+switch to consuming them from there directly.