clang-tools  10.0.0git
ExpandMacro.cpp
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1 //===--- ExpandMacro.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 
9 #include "refactor/Tweak.h"
10 #include "clang/Basic/SourceLocation.h"
11 #include "clang/Basic/SourceManager.h"
12 #include "clang/Basic/TokenKinds.h"
13 #include "clang/Tooling/Core/Replacement.h"
14 #include "clang/Tooling/Syntax/Tokens.h"
15 #include "llvm/ADT/ArrayRef.h"
16 #include "llvm/ADT/STLExtras.h"
17 #include "llvm/Support/Error.h"
18 #include <string>
19 namespace clang {
20 namespace clangd {
21 namespace {
22 
23 /// Replaces a reference to a macro under the cursor with its expansion.
24 /// Before:
25 /// #define FOO(X) X+X
26 /// FOO(10*a)
27 /// ^^^
28 /// After:
29 /// #define FOO(X) X+X
30 /// 10*a+10*a
31 class ExpandMacro : public Tweak {
32 public:
33  const char *id() const override final;
34  Intent intent() const override { return Intent::Refactor; }
35 
36  bool prepare(const Selection &Inputs) override;
37  Expected<Tweak::Effect> apply(const Selection &Inputs) override;
38  std::string title() const override;
39 
40 private:
41  syntax::TokenBuffer::Expansion Expansion;
42  std::string MacroName;
43 };
44 
45 REGISTER_TWEAK(ExpandMacro)
46 
47 /// Finds a spelled token that the cursor is pointing at.
48 static const syntax::Token *
49 findTokenUnderCursor(const SourceManager &SM,
50  llvm::ArrayRef<syntax::Token> Spelled,
51  unsigned CursorOffset) {
52  // Find the token that strats after the offset, then look at a previous one.
53  auto It = llvm::partition_point(Spelled, [&](const syntax::Token &T) {
54  assert(T.location().isFileID());
55  return SM.getFileOffset(T.location()) <= CursorOffset;
56  });
57  if (It == Spelled.begin())
58  return nullptr;
59  // Check the token we found actually touches the cursor position.
60  --It;
61  return It->range(SM).touches(CursorOffset) ? It : nullptr;
62 }
63 
64 static const syntax::Token *
65 findIdentifierUnderCursor(const syntax::TokenBuffer &Tokens,
66  SourceLocation Cursor) {
67  assert(Cursor.isFileID());
68 
69  auto &SM = Tokens.sourceManager();
70  auto Spelled = Tokens.spelledTokens(SM.getFileID(Cursor));
71 
72  auto *T = findTokenUnderCursor(SM, Spelled, SM.getFileOffset(Cursor));
73  if (!T)
74  return nullptr;
75  if (T->kind() == tok::identifier)
76  return T;
77  // Also try the previous token when the cursor is at the boundary, e.g.
78  // FOO^()
79  // FOO^+
80  if (T == Spelled.begin())
81  return nullptr;
82  --T;
83  if (T->endLocation() != Cursor || T->kind() != tok::identifier)
84  return nullptr;
85  return T;
86 }
87 
88 bool ExpandMacro::prepare(const Selection &Inputs) {
89  // FIXME: we currently succeed on selection at the end of the token, e.g.
90  // 'FOO[[ ]]BAR'. We should not trigger in that case.
91 
92  // Find a token under the cursor.
93  auto *T = findIdentifierUnderCursor(Inputs.AST->getTokens(), Inputs.Cursor);
94  // We are interested only in identifiers, other tokens can't be macro names.
95  if (!T)
96  return false;
97  // If the identifier is a macro we will find the corresponding expansion.
98  auto Expansion = Inputs.AST->getTokens().expansionStartingAt(T);
99  if (!Expansion)
100  return false;
101  this->MacroName = T->text(Inputs.AST->getSourceManager());
102  this->Expansion = *Expansion;
103  return true;
104 }
105 
106 Expected<Tweak::Effect> ExpandMacro::apply(const Selection &Inputs) {
107  auto &SM = Inputs.AST->getSourceManager();
108 
109  std::string Replacement;
110  for (const syntax::Token &T : Expansion.Expanded) {
111  Replacement += T.text(SM);
112  Replacement += " ";
113  }
114  if (!Replacement.empty()) {
115  assert(Replacement.back() == ' ');
116  Replacement.pop_back();
117  }
118 
119  CharSourceRange MacroRange =
120  CharSourceRange::getCharRange(Expansion.Spelled.front().location(),
121  Expansion.Spelled.back().endLocation());
122 
123  tooling::Replacements Reps;
124  llvm::cantFail(Reps.add(tooling::Replacement(SM, MacroRange, Replacement)));
125  return Effect::mainFileEdit(SM, std::move(Reps));
126 }
127 
128 std::string ExpandMacro::title() const {
129  return llvm::formatv("Expand macro '{0}'", MacroName);
130 }
131 
132 } // namespace
133 } // namespace clangd
134 } // namespace clang
#define REGISTER_TWEAK(Subclass)
Definition: Tweak.h:129
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//