clang-tools-extra/clangd/refactor/tweaks/DumpAST.cpp

   1 //===--- DumpAST.cpp ---------------------------------------------*- C++-*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 // Defines a few tweaks that expose AST and related information.
   9 // Some of these are fairly clang-specific and hidden (e.g. textual AST dumps).
  10 // Others are more generally useful (class layout) and are exposed by default.
  11 //===----------------------------------------------------------------------===//
  12 #include "XRefs.h"
  13 #include "refactor/Tweak.h"
  14 #include "clang/AST/ASTTypeTraits.h"
  15 #include "clang/AST/Type.h"
  16 #include "llvm/Support/FormatVariadic.h"
  17 #include "llvm/Support/ScopedPrinter.h"
  18 #include "llvm/Support/raw_ostream.h"
  19 #include <optional>
  20
  21 namespace clang {
  22 namespace clangd {
  23 namespace {
  24
  25 /// Dumps the AST of the selected node.
  26 /// Input:
  27 ///   fcall("foo");
  28 ///   ^^^^^
  29 /// Message:
  30 ///   CallExpr
  31 ///   |-DeclRefExpr fcall
  32 ///   `-StringLiteral "foo"
  33 class DumpAST : public Tweak {
  34 public:
  35   const char *id() const final;
  36
  37   bool prepare(const Selection &Inputs) override {
  38     for (auto *N = Inputs.ASTSelection.commonAncestor(); N && !Node;
  39          N = N->Parent)
  40       if (dumpable(N->ASTNode))
  41         Node = N->ASTNode;
  42     return Node.has_value();
  43   }
  44   Expected<Effect> apply(const Selection &Inputs) override;
  45   std::string title() const override {
  46     return std::string(
  47         llvm::formatv("Dump {0} AST", Node->getNodeKind().asStringRef()));
  48   }
  49   llvm::StringLiteral kind() const override { return CodeAction::INFO_KIND; }
  50   bool hidden() const override { return true; }
  51
  52 private:
  53   static bool dumpable(const DynTypedNode &N) {
  54     // Sadly not all node types can be dumped, and there's no API to check.
  55     // See DynTypedNode::dump().
  56     return N.get<Decl>() || N.get<Stmt>() || N.get<Type>();
  57   }
  58
  59   std::optional<DynTypedNode> Node;
  60 };
  61 REGISTER_TWEAK(DumpAST)
  62
  63 llvm::Expected<Tweak::Effect> DumpAST::apply(const Selection &Inputs) {
  64   std::string Str;
  65   llvm::raw_string_ostream OS(Str);
  66   Node->dump(OS, Inputs.AST->getASTContext());
  67   return Effect::showMessage(std::move(OS.str()));
  68 }
  69
  70 /// Dumps the SelectionTree.
  71 /// Input:
  72 /// int fcall(int);
  73 /// void foo() {
  74 ///   fcall(2 + 2);
  75 ///     ^^^^^
  76 /// }
  77 /// Message:
  78 /// TranslationUnitDecl
  79 ///   FunctionDecl void foo()
  80 ///     CompoundStmt {}
  81 ///      .CallExpr fcall(2 + 2)
  82 ///        ImplicitCastExpr fcall
  83 ///         .DeclRefExpr fcall
  84 ///        BinaryOperator 2 + 2
  85 ///          *IntegerLiteral 2
  86 class ShowSelectionTree : public Tweak {
  87 public:
  88   const char *id() const final;
  89
  90   bool prepare(const Selection &Inputs) override { return true; }
  91   Expected<Effect> apply(const Selection &Inputs) override {
  92     return Effect::showMessage(llvm::to_string(Inputs.ASTSelection));
  93   }
  94   std::string title() const override { return "Show selection tree"; }
  95   llvm::StringLiteral kind() const override { return CodeAction::INFO_KIND; }
  96   bool hidden() const override { return true; }
  97 };
  98 REGISTER_TWEAK(ShowSelectionTree)
  99
 100 /// Dumps the symbol under the cursor.
 101 /// Inputs:
 102 /// void foo();
 103 ///      ^^^
 104 /// Message:
 105 ///  foo -
 106 ///  {"containerName":null,"id":"CA2EBE44A1D76D2A","name":"foo","usr":"c:@F@foo#"}
 107 class DumpSymbol : public Tweak {
 108   const char *id() const final;
 109   bool prepare(const Selection &Inputs) override { return true; }
 110   Expected<Effect> apply(const Selection &Inputs) override {
 111     std::string Storage;
 112     llvm::raw_string_ostream Out(Storage);
 113
 114     for (auto &Sym : getSymbolInfo(
 115              *Inputs.AST, sourceLocToPosition(Inputs.AST->getSourceManager(),
 116                                               Inputs.Cursor)))
 117       Out << Sym;
 118     return Effect::showMessage(Out.str());
 119   }
 120   std::string title() const override { return "Dump symbol under the cursor"; }
 121   llvm::StringLiteral kind() const override { return CodeAction::INFO_KIND; }
 122   bool hidden() const override { return true; }
 123 };
 124 REGISTER_TWEAK(DumpSymbol)
 125
 126 /// Shows the layout of the RecordDecl under the cursor.
 127 /// Input:
 128 /// struct X { int foo; };
 129 /// ^^^^^^^^
 130 /// Message:
 131 ///        0 | struct S
 132 ///        0 |   int foo
 133 ///          | [sizeof=4, dsize=4, align=4,
 134 ///          |  nvsize=4, nvalign=4]
 135 class DumpRecordLayout : public Tweak {
 136 public:
 137   const char *id() const final;
 138
 139   bool prepare(const Selection &Inputs) override {
 140     if (auto *Node = Inputs.ASTSelection.commonAncestor())
 141       if (auto *D = Node->ASTNode.get<Decl>())
 142         Record = dyn_cast<RecordDecl>(D);
 143     return Record && Record->isThisDeclarationADefinition() &&
 144            !Record->isDependentType();
 145   }
 146   Expected<Effect> apply(const Selection &Inputs) override {
 147     std::string Str;
 148     llvm::raw_string_ostream OS(Str);
 149     Inputs.AST->getASTContext().DumpRecordLayout(Record, OS);
 150     return Effect::showMessage(std::move(OS.str()));
 151   }
 152   std::string title() const override {
 153     return std::string(llvm::formatv(
 154         "Show {0} layout",
 155         TypeWithKeyword::getTagTypeKindName(Record->getTagKind())));
 156   }
 157   llvm::StringLiteral kind() const override { return CodeAction::INFO_KIND; }
 158   // FIXME: this is interesting to most users. However:
 159   //  - triggering is too broad (e.g. triggers on comments within a class)
 160   //  - showMessage has inconsistent UX (e.g. newlines are stripped in VSCode)
 161   //  - the output itself is a bit hard to decipher.
 162   bool hidden() const override { return true; }
 163
 164 private:
 165   const RecordDecl *Record = nullptr;
 166 };
 167 REGISTER_TWEAK(DumpRecordLayout)
 168
 169 } // namespace
 170 } // namespace clangd
 171 } // namespace clang