| //===--- InlayHints.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 "InlayHints.h" |
| #include "AST.h" |
| #include "Config.h" |
| #include "HeuristicResolver.h" |
| #include "ParsedAST.h" |
| #include "SourceCode.h" |
| #include "clang/AST/Decl.h" |
| #include "clang/AST/DeclarationName.h" |
| #include "clang/AST/ExprCXX.h" |
| #include "clang/AST/RecursiveASTVisitor.h" |
| #include "clang/Basic/Builtins.h" |
| #include "clang/Basic/SourceManager.h" |
| #include "llvm/ADT/ScopeExit.h" |
| #include <optional> |
| |
| namespace clang { |
| namespace clangd { |
| namespace { |
| |
| // For now, inlay hints are always anchored at the left or right of their range. |
| enum class HintSide { Left, Right }; |
| |
| // Helper class to iterate over the designator names of an aggregate type. |
| // |
| // For an array type, yields [0], [1], [2]... |
| // For aggregate classes, yields null for each base, then .field1, .field2, ... |
| class AggregateDesignatorNames { |
| public: |
| AggregateDesignatorNames(QualType T) { |
| if (!T.isNull()) { |
| T = T.getCanonicalType(); |
| if (T->isArrayType()) { |
| IsArray = true; |
| Valid = true; |
| return; |
| } |
| if (const RecordDecl *RD = T->getAsRecordDecl()) { |
| Valid = true; |
| FieldsIt = RD->field_begin(); |
| FieldsEnd = RD->field_end(); |
| if (const auto *CRD = llvm::dyn_cast<CXXRecordDecl>(RD)) { |
| BasesIt = CRD->bases_begin(); |
| BasesEnd = CRD->bases_end(); |
| Valid = CRD->isAggregate(); |
| } |
| OneField = Valid && BasesIt == BasesEnd && FieldsIt != FieldsEnd && |
| std::next(FieldsIt) == FieldsEnd; |
| } |
| } |
| } |
| // Returns false if the type was not an aggregate. |
| operator bool() { return Valid; } |
| // Advance to the next element in the aggregate. |
| void next() { |
| if (IsArray) |
| ++Index; |
| else if (BasesIt != BasesEnd) |
| ++BasesIt; |
| else if (FieldsIt != FieldsEnd) |
| ++FieldsIt; |
| } |
| // Print the designator to Out. |
| // Returns false if we could not produce a designator for this element. |
| bool append(std::string &Out, bool ForSubobject) { |
| if (IsArray) { |
| Out.push_back('['); |
| Out.append(std::to_string(Index)); |
| Out.push_back(']'); |
| return true; |
| } |
| if (BasesIt != BasesEnd) |
| return false; // Bases can't be designated. Should we make one up? |
| if (FieldsIt != FieldsEnd) { |
| llvm::StringRef FieldName; |
| if (const IdentifierInfo *II = FieldsIt->getIdentifier()) |
| FieldName = II->getName(); |
| |
| // For certain objects, their subobjects may be named directly. |
| if (ForSubobject && |
| (FieldsIt->isAnonymousStructOrUnion() || |
| // std::array<int,3> x = {1,2,3}. Designators not strictly valid! |
| (OneField && isReservedName(FieldName)))) |
| return true; |
| |
| if (!FieldName.empty() && !isReservedName(FieldName)) { |
| Out.push_back('.'); |
| Out.append(FieldName.begin(), FieldName.end()); |
| return true; |
| } |
| return false; |
| } |
| return false; |
| } |
| |
| private: |
| bool Valid = false; |
| bool IsArray = false; |
| bool OneField = false; // e.g. std::array { T __elements[N]; } |
| unsigned Index = 0; |
| CXXRecordDecl::base_class_const_iterator BasesIt; |
| CXXRecordDecl::base_class_const_iterator BasesEnd; |
| RecordDecl::field_iterator FieldsIt; |
| RecordDecl::field_iterator FieldsEnd; |
| }; |
| |
| // Collect designator labels describing the elements of an init list. |
| // |
| // This function contributes the designators of some (sub)object, which is |
| // represented by the semantic InitListExpr Sem. |
| // This includes any nested subobjects, but *only* if they are part of the same |
| // original syntactic init list (due to brace elision). |
| // In other words, it may descend into subobjects but not written init-lists. |
| // |
| // For example: struct Outer { Inner a,b; }; struct Inner { int x, y; } |
| // Outer o{{1, 2}, 3}; |
| // This function will be called with Sem = { {1, 2}, {3, ImplicitValue} } |
| // It should generate designators '.a:' and '.b.x:'. |
| // '.a:' is produced directly without recursing into the written sublist. |
| // (The written sublist will have a separate collectDesignators() call later). |
| // Recursion with Prefix='.b' and Sem = {3, ImplicitValue} produces '.b.x:'. |
| void collectDesignators(const InitListExpr *Sem, |
| llvm::DenseMap<SourceLocation, std::string> &Out, |
| const llvm::DenseSet<SourceLocation> &NestedBraces, |
| std::string &Prefix) { |
| if (!Sem || Sem->isTransparent()) |
| return; |
| assert(Sem->isSemanticForm()); |
| |
| // The elements of the semantic form all correspond to direct subobjects of |
| // the aggregate type. `Fields` iterates over these subobject names. |
| AggregateDesignatorNames Fields(Sem->getType()); |
| if (!Fields) |
| return; |
| for (const Expr *Init : Sem->inits()) { |
| auto Next = llvm::make_scope_exit([&, Size(Prefix.size())] { |
| Fields.next(); // Always advance to the next subobject name. |
| Prefix.resize(Size); // Erase any designator we appended. |
| }); |
| // Skip for a broken initializer or if it is a "hole" in a subobject that |
| // was not explicitly initialized. |
| if (!Init || llvm::isa<ImplicitValueInitExpr>(Init)) |
| continue; |
| |
| const auto *BraceElidedSubobject = llvm::dyn_cast<InitListExpr>(Init); |
| if (BraceElidedSubobject && |
| NestedBraces.contains(BraceElidedSubobject->getLBraceLoc())) |
| BraceElidedSubobject = nullptr; // there were braces! |
| |
| if (!Fields.append(Prefix, BraceElidedSubobject != nullptr)) |
| continue; // no designator available for this subobject |
| if (BraceElidedSubobject) { |
| // If the braces were elided, this aggregate subobject is initialized |
| // inline in the same syntactic list. |
| // Descend into the semantic list describing the subobject. |
| // (NestedBraces are still correct, they're from the same syntactic list). |
| collectDesignators(BraceElidedSubobject, Out, NestedBraces, Prefix); |
| continue; |
| } |
| Out.try_emplace(Init->getBeginLoc(), Prefix); |
| } |
| } |
| |
| // Get designators describing the elements of a (syntactic) init list. |
| // This does not produce designators for any explicitly-written nested lists. |
| llvm::DenseMap<SourceLocation, std::string> |
| getDesignators(const InitListExpr *Syn) { |
| assert(Syn->isSyntacticForm()); |
| |
| // collectDesignators needs to know which InitListExprs in the semantic tree |
| // were actually written, but InitListExpr::isExplicit() lies. |
| // Instead, record where braces of sub-init-lists occur in the syntactic form. |
| llvm::DenseSet<SourceLocation> NestedBraces; |
| for (const Expr *Init : Syn->inits()) |
| if (auto *Nested = llvm::dyn_cast<InitListExpr>(Init)) |
| NestedBraces.insert(Nested->getLBraceLoc()); |
| |
| // Traverse the semantic form to find the designators. |
| // We use their SourceLocation to correlate with the syntactic form later. |
| llvm::DenseMap<SourceLocation, std::string> Designators; |
| std::string EmptyPrefix; |
| collectDesignators(Syn->isSemanticForm() ? Syn : Syn->getSemanticForm(), |
| Designators, NestedBraces, EmptyPrefix); |
| return Designators; |
| } |
| |
| class InlayHintVisitor : public RecursiveASTVisitor<InlayHintVisitor> { |
| public: |
| InlayHintVisitor(std::vector<InlayHint> &Results, ParsedAST &AST, |
| const Config &Cfg, std::optional<Range> RestrictRange) |
| : Results(Results), AST(AST.getASTContext()), Tokens(AST.getTokens()), |
| Cfg(Cfg), RestrictRange(std::move(RestrictRange)), |
| MainFileID(AST.getSourceManager().getMainFileID()), |
| Resolver(AST.getHeuristicResolver()), |
| TypeHintPolicy(this->AST.getPrintingPolicy()), |
| StructuredBindingPolicy(this->AST.getPrintingPolicy()) { |
| bool Invalid = false; |
| llvm::StringRef Buf = |
| AST.getSourceManager().getBufferData(MainFileID, &Invalid); |
| MainFileBuf = Invalid ? StringRef{} : Buf; |
| |
| TypeHintPolicy.SuppressScope = true; // keep type names short |
| TypeHintPolicy.AnonymousTagLocations = |
| false; // do not print lambda locations |
| |
| // For structured bindings, print canonical types. This is important because |
| // for bindings that use the tuple_element protocol, the non-canonical types |
| // would be "tuple_element<I, A>::type". |
| // For "auto", we often prefer sugared types. |
| // Not setting PrintCanonicalTypes for "auto" allows |
| // SuppressDefaultTemplateArgs (set by default) to have an effect. |
| StructuredBindingPolicy = TypeHintPolicy; |
| StructuredBindingPolicy.PrintCanonicalTypes = true; |
| } |
| |
| bool VisitTypeLoc(TypeLoc TL) { |
| if (const auto *DT = llvm::dyn_cast<DecltypeType>(TL.getType())) |
| if (QualType UT = DT->getUnderlyingType(); !UT->isDependentType()) |
| addTypeHint(TL.getSourceRange(), UT, ": "); |
| return true; |
| } |
| |
| bool VisitCXXConstructExpr(CXXConstructExpr *E) { |
| // Weed out constructor calls that don't look like a function call with |
| // an argument list, by checking the validity of getParenOrBraceRange(). |
| // Also weed out std::initializer_list constructors as there are no names |
| // for the individual arguments. |
| if (!E->getParenOrBraceRange().isValid() || |
| E->isStdInitListInitialization()) { |
| return true; |
| } |
| |
| processCall(E->getConstructor(), {E->getArgs(), E->getNumArgs()}); |
| return true; |
| } |
| |
| bool VisitCallExpr(CallExpr *E) { |
| if (!Cfg.InlayHints.Parameters) |
| return true; |
| |
| // Do not show parameter hints for operator calls written using operator |
| // syntax or user-defined literals. (Among other reasons, the resulting |
| // hints can look awkard, e.g. the expression can itself be a function |
| // argument and then we'd get two hints side by side). |
| if (isa<CXXOperatorCallExpr>(E) || isa<UserDefinedLiteral>(E)) |
| return true; |
| |
| auto CalleeDecls = Resolver->resolveCalleeOfCallExpr(E); |
| if (CalleeDecls.size() != 1) |
| return true; |
| const FunctionDecl *Callee = nullptr; |
| if (const auto *FD = dyn_cast<FunctionDecl>(CalleeDecls[0])) |
| Callee = FD; |
| else if (const auto *FTD = dyn_cast<FunctionTemplateDecl>(CalleeDecls[0])) |
| Callee = FTD->getTemplatedDecl(); |
| if (!Callee) |
| return true; |
| |
| processCall(Callee, {E->getArgs(), E->getNumArgs()}); |
| return true; |
| } |
| |
| bool VisitFunctionDecl(FunctionDecl *D) { |
| if (auto *FPT = |
| llvm::dyn_cast<FunctionProtoType>(D->getType().getTypePtr())) { |
| if (!FPT->hasTrailingReturn()) { |
| if (auto FTL = D->getFunctionTypeLoc()) |
| addReturnTypeHint(D, FTL.getRParenLoc()); |
| } |
| } |
| return true; |
| } |
| |
| bool VisitLambdaExpr(LambdaExpr *E) { |
| FunctionDecl *D = E->getCallOperator(); |
| if (!E->hasExplicitResultType()) |
| addReturnTypeHint(D, E->hasExplicitParameters() |
| ? D->getFunctionTypeLoc().getRParenLoc() |
| : E->getIntroducerRange().getEnd()); |
| return true; |
| } |
| |
| void addReturnTypeHint(FunctionDecl *D, SourceRange Range) { |
| auto *AT = D->getReturnType()->getContainedAutoType(); |
| if (!AT || AT->getDeducedType().isNull()) |
| return; |
| addTypeHint(Range, D->getReturnType(), /*Prefix=*/"-> "); |
| } |
| |
| bool VisitVarDecl(VarDecl *D) { |
| // Do not show hints for the aggregate in a structured binding, |
| // but show hints for the individual bindings. |
| if (auto *DD = dyn_cast<DecompositionDecl>(D)) { |
| for (auto *Binding : DD->bindings()) { |
| addTypeHint(Binding->getLocation(), Binding->getType(), /*Prefix=*/": ", |
| StructuredBindingPolicy); |
| } |
| return true; |
| } |
| |
| if (D->getType()->getContainedAutoType()) { |
| if (!D->getType()->isDependentType()) { |
| // Our current approach is to place the hint on the variable |
| // and accordingly print the full type |
| // (e.g. for `const auto& x = 42`, print `const int&`). |
| // Alternatively, we could place the hint on the `auto` |
| // (and then just print the type deduced for the `auto`). |
| addTypeHint(D->getLocation(), D->getType(), /*Prefix=*/": "); |
| } |
| } |
| |
| // Handle templates like `int foo(auto x)` with exactly one instantiation. |
| if (auto *PVD = llvm::dyn_cast<ParmVarDecl>(D)) { |
| if (D->getIdentifier() && PVD->getType()->isDependentType() && |
| !getContainedAutoParamType(D->getTypeSourceInfo()->getTypeLoc()) |
| .isNull()) { |
| if (auto *IPVD = getOnlyParamInstantiation(PVD)) |
| addTypeHint(D->getLocation(), IPVD->getType(), /*Prefix=*/": "); |
| } |
| } |
| |
| return true; |
| } |
| |
| ParmVarDecl *getOnlyParamInstantiation(ParmVarDecl *D) { |
| auto *TemplateFunction = llvm::dyn_cast<FunctionDecl>(D->getDeclContext()); |
| if (!TemplateFunction) |
| return nullptr; |
| auto *InstantiatedFunction = llvm::dyn_cast_or_null<FunctionDecl>( |
| getOnlyInstantiation(TemplateFunction)); |
| if (!InstantiatedFunction) |
| return nullptr; |
| |
| unsigned ParamIdx = 0; |
| for (auto *Param : TemplateFunction->parameters()) { |
| // Can't reason about param indexes in the presence of preceding packs. |
| // And if this param is a pack, it may expand to multiple params. |
| if (Param->isParameterPack()) |
| return nullptr; |
| if (Param == D) |
| break; |
| ++ParamIdx; |
| } |
| assert(ParamIdx < TemplateFunction->getNumParams() && |
| "Couldn't find param in list?"); |
| assert(ParamIdx < InstantiatedFunction->getNumParams() && |
| "Instantiated function has fewer (non-pack) parameters?"); |
| return InstantiatedFunction->getParamDecl(ParamIdx); |
| } |
| |
| bool VisitInitListExpr(InitListExpr *Syn) { |
| // We receive the syntactic form here (shouldVisitImplicitCode() is false). |
| // This is the one we will ultimately attach designators to. |
| // It may have subobject initializers inlined without braces. The *semantic* |
| // form of the init-list has nested init-lists for these. |
| // getDesignators will look at the semantic form to determine the labels. |
| assert(Syn->isSyntacticForm() && "RAV should not visit implicit code!"); |
| if (!Cfg.InlayHints.Designators) |
| return true; |
| if (Syn->isIdiomaticZeroInitializer(AST.getLangOpts())) |
| return true; |
| llvm::DenseMap<SourceLocation, std::string> Designators = |
| getDesignators(Syn); |
| for (const Expr *Init : Syn->inits()) { |
| if (llvm::isa<DesignatedInitExpr>(Init)) |
| continue; |
| auto It = Designators.find(Init->getBeginLoc()); |
| if (It != Designators.end() && |
| !isPrecededByParamNameComment(Init, It->second)) |
| addDesignatorHint(Init->getSourceRange(), It->second); |
| } |
| return true; |
| } |
| |
| // FIXME: Handle RecoveryExpr to try to hint some invalid calls. |
| |
| private: |
| using NameVec = SmallVector<StringRef, 8>; |
| |
| void processCall(const FunctionDecl *Callee, |
| llvm::ArrayRef<const Expr *> Args) { |
| if (!Cfg.InlayHints.Parameters || Args.size() == 0 || !Callee) |
| return; |
| |
| // The parameter name of a move or copy constructor is not very interesting. |
| if (auto *Ctor = dyn_cast<CXXConstructorDecl>(Callee)) |
| if (Ctor->isCopyOrMoveConstructor()) |
| return; |
| |
| // Resolve parameter packs to their forwarded parameter |
| auto ForwardedParams = resolveForwardingParameters(Callee); |
| |
| NameVec ParameterNames = chooseParameterNames(ForwardedParams); |
| |
| // Exclude setters (i.e. functions with one argument whose name begins with |
| // "set"), and builtins like std::move/forward/... as their parameter name |
| // is also not likely to be interesting. |
| if (isSetter(Callee, ParameterNames) || isSimpleBuiltin(Callee)) |
| return; |
| |
| for (size_t I = 0; I < ParameterNames.size() && I < Args.size(); ++I) { |
| // Pack expansion expressions cause the 1:1 mapping between arguments and |
| // parameters to break down, so we don't add further inlay hints if we |
| // encounter one. |
| if (isa<PackExpansionExpr>(Args[I])) { |
| break; |
| } |
| |
| StringRef Name = ParameterNames[I]; |
| bool NameHint = shouldHintName(Args[I], Name); |
| bool ReferenceHint = |
| shouldHintReference(Callee->getParamDecl(I), ForwardedParams[I]); |
| |
| if (NameHint || ReferenceHint) { |
| addInlayHint(Args[I]->getSourceRange(), HintSide::Left, |
| InlayHintKind::Parameter, ReferenceHint ? "&" : "", |
| NameHint ? Name : "", ": "); |
| } |
| } |
| } |
| |
| static bool isSetter(const FunctionDecl *Callee, const NameVec &ParamNames) { |
| if (ParamNames.size() != 1) |
| return false; |
| |
| StringRef Name = getSimpleName(*Callee); |
| if (!Name.startswith_insensitive("set")) |
| return false; |
| |
| // In addition to checking that the function has one parameter and its |
| // name starts with "set", also check that the part after "set" matches |
| // the name of the parameter (ignoring case). The idea here is that if |
| // the parameter name differs, it may contain extra information that |
| // may be useful to show in a hint, as in: |
| // void setTimeout(int timeoutMillis); |
| // This currently doesn't handle cases where params use snake_case |
| // and functions don't, e.g. |
| // void setExceptionHandler(EHFunc exception_handler); |
| // We could improve this by replacing `equals_insensitive` with some |
| // `sloppy_equals` which ignores case and also skips underscores. |
| StringRef WhatItIsSetting = Name.substr(3).ltrim("_"); |
| return WhatItIsSetting.equals_insensitive(ParamNames[0]); |
| } |
| |
| // Checks if the callee is one of the builtins |
| // addressof, as_const, forward, move(_if_noexcept) |
| static bool isSimpleBuiltin(const FunctionDecl *Callee) { |
| switch (Callee->getBuiltinID()) { |
| case Builtin::BIaddressof: |
| case Builtin::BIas_const: |
| case Builtin::BIforward: |
| case Builtin::BImove: |
| case Builtin::BImove_if_noexcept: |
| return true; |
| default: |
| return false; |
| } |
| } |
| |
| bool shouldHintName(const Expr *Arg, StringRef ParamName) { |
| if (ParamName.empty()) |
| return false; |
| |
| // If the argument expression is a single name and it matches the |
| // parameter name exactly, omit the name hint. |
| if (ParamName == getSpelledIdentifier(Arg)) |
| return false; |
| |
| // Exclude argument expressions preceded by a /*paramName*/. |
| if (isPrecededByParamNameComment(Arg, ParamName)) |
| return false; |
| |
| return true; |
| } |
| |
| bool shouldHintReference(const ParmVarDecl *Param, |
| const ParmVarDecl *ForwardedParam) { |
| // We add a & hint only when the argument is passed as mutable reference. |
| // For parameters that are not part of an expanded pack, this is |
| // straightforward. For expanded pack parameters, it's likely that they will |
| // be forwarded to another function. In this situation, we only want to add |
| // the reference hint if the argument is actually being used via mutable |
| // reference. This means we need to check |
| // 1. whether the value category of the argument is preserved, i.e. each |
| // pack expansion uses std::forward correctly. |
| // 2. whether the argument is ever copied/cast instead of passed |
| // by-reference |
| // Instead of checking this explicitly, we use the following proxy: |
| // 1. the value category can only change from rvalue to lvalue during |
| // forwarding, so checking whether both the parameter of the forwarding |
| // function and the forwarded function are lvalue references detects such |
| // a conversion. |
| // 2. if the argument is copied/cast somewhere in the chain of forwarding |
| // calls, it can only be passed on to an rvalue reference or const lvalue |
| // reference parameter. Thus if the forwarded parameter is a mutable |
| // lvalue reference, it cannot have been copied/cast to on the way. |
| // Additionally, we should not add a reference hint if the forwarded |
| // parameter was only partially resolved, i.e. points to an expanded pack |
| // parameter, since we do not know how it will be used eventually. |
| auto Type = Param->getType(); |
| auto ForwardedType = ForwardedParam->getType(); |
| return Type->isLValueReferenceType() && |
| ForwardedType->isLValueReferenceType() && |
| !ForwardedType.getNonReferenceType().isConstQualified() && |
| !isExpandedFromParameterPack(ForwardedParam); |
| } |
| |
| // Checks if "E" is spelled in the main file and preceded by a C-style comment |
| // whose contents match ParamName (allowing for whitespace and an optional "=" |
| // at the end. |
| bool isPrecededByParamNameComment(const Expr *E, StringRef ParamName) { |
| auto &SM = AST.getSourceManager(); |
| auto ExprStartLoc = SM.getTopMacroCallerLoc(E->getBeginLoc()); |
| auto Decomposed = SM.getDecomposedLoc(ExprStartLoc); |
| if (Decomposed.first != MainFileID) |
| return false; |
| |
| StringRef SourcePrefix = MainFileBuf.substr(0, Decomposed.second); |
| // Allow whitespace between comment and expression. |
| SourcePrefix = SourcePrefix.rtrim(); |
| // Check for comment ending. |
| if (!SourcePrefix.consume_back("*/")) |
| return false; |
| // Ignore some punctuation and whitespace around comment. |
| // In particular this allows designators to match nicely. |
| llvm::StringLiteral IgnoreChars = " =."; |
| SourcePrefix = SourcePrefix.rtrim(IgnoreChars); |
| ParamName = ParamName.trim(IgnoreChars); |
| // Other than that, the comment must contain exactly ParamName. |
| if (!SourcePrefix.consume_back(ParamName)) |
| return false; |
| SourcePrefix = SourcePrefix.rtrim(IgnoreChars); |
| return SourcePrefix.endswith("/*"); |
| } |
| |
| // If "E" spells a single unqualified identifier, return that name. |
| // Otherwise, return an empty string. |
| static StringRef getSpelledIdentifier(const Expr *E) { |
| E = E->IgnoreUnlessSpelledInSource(); |
| |
| if (auto *DRE = dyn_cast<DeclRefExpr>(E)) |
| if (!DRE->getQualifier()) |
| return getSimpleName(*DRE->getDecl()); |
| |
| if (auto *ME = dyn_cast<MemberExpr>(E)) |
| if (!ME->getQualifier() && ME->isImplicitAccess()) |
| return getSimpleName(*ME->getMemberDecl()); |
| |
| return {}; |
| } |
| |
| NameVec chooseParameterNames(SmallVector<const ParmVarDecl *> Parameters) { |
| NameVec ParameterNames; |
| for (const auto *P : Parameters) { |
| if (isExpandedFromParameterPack(P)) { |
| // If we haven't resolved a pack paramater (e.g. foo(Args... args)) to a |
| // non-pack parameter, then hinting as foo(args: 1, args: 2, args: 3) is |
| // unlikely to be useful. |
| ParameterNames.emplace_back(); |
| } else { |
| auto SimpleName = getSimpleName(*P); |
| // If the parameter is unnamed in the declaration: |
| // attempt to get its name from the definition |
| if (SimpleName.empty()) { |
| if (const auto *PD = getParamDefinition(P)) { |
| SimpleName = getSimpleName(*PD); |
| } |
| } |
| ParameterNames.emplace_back(SimpleName); |
| } |
| } |
| |
| // Standard library functions often have parameter names that start |
| // with underscores, which makes the hints noisy, so strip them out. |
| for (auto &Name : ParameterNames) |
| stripLeadingUnderscores(Name); |
| |
| return ParameterNames; |
| } |
| |
| // for a ParmVarDecl from a function declaration, returns the corresponding |
| // ParmVarDecl from the definition if possible, nullptr otherwise. |
| static const ParmVarDecl *getParamDefinition(const ParmVarDecl *P) { |
| if (auto *Callee = dyn_cast<FunctionDecl>(P->getDeclContext())) { |
| if (auto *Def = Callee->getDefinition()) { |
| auto I = std::distance(Callee->param_begin(), |
| llvm::find(Callee->parameters(), P)); |
| if (I < Callee->getNumParams()) { |
| return Def->getParamDecl(I); |
| } |
| } |
| } |
| return nullptr; |
| } |
| |
| static void stripLeadingUnderscores(StringRef &Name) { |
| Name = Name.ltrim('_'); |
| } |
| |
| static StringRef getSimpleName(const NamedDecl &D) { |
| if (IdentifierInfo *Ident = D.getDeclName().getAsIdentifierInfo()) { |
| return Ident->getName(); |
| } |
| |
| return StringRef(); |
| } |
| |
| // We pass HintSide rather than SourceLocation because we want to ensure |
| // it is in the same file as the common file range. |
| void addInlayHint(SourceRange R, HintSide Side, InlayHintKind Kind, |
| llvm::StringRef Prefix, llvm::StringRef Label, |
| llvm::StringRef Suffix) { |
| // We shouldn't get as far as adding a hint if the category is disabled. |
| // We'd like to disable as much of the analysis as possible above instead. |
| // Assert in debug mode but add a dynamic check in production. |
| assert(Cfg.InlayHints.Enabled && "Shouldn't get here if disabled!"); |
| switch (Kind) { |
| #define CHECK_KIND(Enumerator, ConfigProperty) \ |
| case InlayHintKind::Enumerator: \ |
| assert(Cfg.InlayHints.ConfigProperty && \ |
| "Shouldn't get here if kind is disabled!"); \ |
| if (!Cfg.InlayHints.ConfigProperty) \ |
| return; \ |
| break |
| CHECK_KIND(Parameter, Parameters); |
| CHECK_KIND(Type, DeducedTypes); |
| CHECK_KIND(Designator, Designators); |
| #undef CHECK_KIND |
| } |
| |
| auto LSPRange = getHintRange(R); |
| if (!LSPRange) |
| return; |
| Position LSPPos = Side == HintSide::Left ? LSPRange->start : LSPRange->end; |
| if (RestrictRange && |
| (LSPPos < RestrictRange->start || !(LSPPos < RestrictRange->end))) |
| return; |
| bool PadLeft = Prefix.consume_front(" "); |
| bool PadRight = Suffix.consume_back(" "); |
| Results.push_back(InlayHint{LSPPos, (Prefix + Label + Suffix).str(), Kind, |
| PadLeft, PadRight, *LSPRange}); |
| } |
| |
| // Get the range of the main file that *exactly* corresponds to R. |
| std::optional<Range> getHintRange(SourceRange R) { |
| const auto &SM = AST.getSourceManager(); |
| auto Spelled = Tokens.spelledForExpanded(Tokens.expandedTokens(R)); |
| // TokenBuffer will return null if e.g. R corresponds to only part of a |
| // macro expansion. |
| if (!Spelled || Spelled->empty()) |
| return std::nullopt; |
| // Hint must be within the main file, not e.g. a non-preamble include. |
| if (SM.getFileID(Spelled->front().location()) != SM.getMainFileID() || |
| SM.getFileID(Spelled->back().location()) != SM.getMainFileID()) |
| return std::nullopt; |
| return Range{sourceLocToPosition(SM, Spelled->front().location()), |
| sourceLocToPosition(SM, Spelled->back().endLocation())}; |
| } |
| |
| static bool shouldPrintCanonicalType(QualType QT) { |
| // The sugared type is more useful in some cases, and the canonical |
| // type in other cases. For now, prefer the sugared type unless |
| // we are printing `decltype(expr)`. This could be refined further |
| // (see https://github.com/clangd/clangd/issues/1298). |
| if (QT->isDecltypeType()) |
| return true; |
| if (const AutoType *AT = QT->getContainedAutoType()) |
| if (!AT->getDeducedType().isNull() && |
| AT->getDeducedType()->isDecltypeType()) |
| return true; |
| return false; |
| } |
| |
| void addTypeHint(SourceRange R, QualType T, llvm::StringRef Prefix) { |
| TypeHintPolicy.PrintCanonicalTypes = shouldPrintCanonicalType(T); |
| addTypeHint(R, T, Prefix, TypeHintPolicy); |
| } |
| |
| void addTypeHint(SourceRange R, QualType T, llvm::StringRef Prefix, |
| const PrintingPolicy &Policy) { |
| if (!Cfg.InlayHints.DeducedTypes || T.isNull()) |
| return; |
| |
| std::string TypeName = T.getAsString(Policy); |
| if (TypeName.length() < TypeNameLimit) |
| addInlayHint(R, HintSide::Right, InlayHintKind::Type, Prefix, TypeName, |
| /*Suffix=*/""); |
| } |
| |
| void addDesignatorHint(SourceRange R, llvm::StringRef Text) { |
| addInlayHint(R, HintSide::Left, InlayHintKind::Designator, |
| /*Prefix=*/"", Text, /*Suffix=*/"="); |
| } |
| |
| std::vector<InlayHint> &Results; |
| ASTContext &AST; |
| const syntax::TokenBuffer &Tokens; |
| const Config &Cfg; |
| std::optional<Range> RestrictRange; |
| FileID MainFileID; |
| StringRef MainFileBuf; |
| const HeuristicResolver *Resolver; |
| // We want to suppress default template arguments, but otherwise print |
| // canonical types. Unfortunately, they're conflicting policies so we can't |
| // have both. For regular types, suppressing template arguments is more |
| // important, whereas printing canonical types is crucial for structured |
| // bindings, so we use two separate policies. (See the constructor where |
| // the policies are initialized for more details.) |
| PrintingPolicy TypeHintPolicy; |
| PrintingPolicy StructuredBindingPolicy; |
| |
| static const size_t TypeNameLimit = 32; |
| }; |
| |
| } // namespace |
| |
| std::vector<InlayHint> inlayHints(ParsedAST &AST, |
| std::optional<Range> RestrictRange) { |
| std::vector<InlayHint> Results; |
| const auto &Cfg = Config::current(); |
| if (!Cfg.InlayHints.Enabled) |
| return Results; |
| InlayHintVisitor Visitor(Results, AST, Cfg, std::move(RestrictRange)); |
| Visitor.TraverseAST(AST.getASTContext()); |
| |
| // De-duplicate hints. Duplicates can sometimes occur due to e.g. explicit |
| // template instantiations. |
| llvm::sort(Results); |
| Results.erase(std::unique(Results.begin(), Results.end()), Results.end()); |
| |
| return Results; |
| } |
| |
| } // namespace clangd |
| } // namespace clang |
