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//===--- ExpandMacro.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 "refactor/Tweak.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TokenKinds.h"
#include "clang/Tooling/Core/Replacement.h"
#include "clang/Tooling/Syntax/Tokens.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/Error.h"
#include <string>
namespace clang {
namespace clangd {
namespace {
/// Replaces a reference to a macro under the cursor with its expansion.
/// Before:
/// #define FOO(X) X+X
/// FOO(10*a)
/// ^^^
/// After:
/// #define FOO(X) X+X
/// 10*a+10*a
class ExpandMacro : public Tweak {
public:
const char *id() const override final;
llvm::StringLiteral kind() const override {
return CodeAction::REFACTOR_KIND;
}
bool prepare(const Selection &Inputs) override;
Expected<Tweak::Effect> apply(const Selection &Inputs) override;
std::string title() const override;
private:
syntax::TokenBuffer::Expansion Expansion;
std::string MacroName;
};
REGISTER_TWEAK(ExpandMacro)
/// Finds a spelled token that the cursor is pointing at.
static const syntax::Token *
findTokenUnderCursor(const SourceManager &SM,
llvm::ArrayRef<syntax::Token> Spelled,
unsigned CursorOffset) {
// Find the token that strats after the offset, then look at a previous one.
auto It = llvm::partition_point(Spelled, [&](const syntax::Token &T) {
assert(T.location().isFileID());
return SM.getFileOffset(T.location()) <= CursorOffset;
});
if (It == Spelled.begin())
return nullptr;
// Check the token we found actually touches the cursor position.
--It;
return It->range(SM).touches(CursorOffset) ? It : nullptr;
}
static const syntax::Token *
findIdentifierUnderCursor(const syntax::TokenBuffer &Tokens,
SourceLocation Cursor) {
assert(Cursor.isFileID());
auto &SM = Tokens.sourceManager();
auto Spelled = Tokens.spelledTokens(SM.getFileID(Cursor));
auto *T = findTokenUnderCursor(SM, Spelled, SM.getFileOffset(Cursor));
if (!T)
return nullptr;
if (T->kind() == tok::identifier)
return T;
// Also try the previous token when the cursor is at the boundary, e.g.
// FOO^()
// FOO^+
if (T == Spelled.begin())
return nullptr;
--T;
if (T->endLocation() != Cursor || T->kind() != tok::identifier)
return nullptr;
return T;
}
bool ExpandMacro::prepare(const Selection &Inputs) {
// FIXME: we currently succeed on selection at the end of the token, e.g.
// 'FOO[[ ]]BAR'. We should not trigger in that case.
// Find a token under the cursor.
auto *T = findIdentifierUnderCursor(Inputs.AST->getTokens(), Inputs.Cursor);
// We are interested only in identifiers, other tokens can't be macro names.
if (!T)
return false;
// If the identifier is a macro we will find the corresponding expansion.
auto Expansion = Inputs.AST->getTokens().expansionStartingAt(T);
if (!Expansion)
return false;
this->MacroName = std::string(T->text(Inputs.AST->getSourceManager()));
this->Expansion = *Expansion;
return true;
}
Expected<Tweak::Effect> ExpandMacro::apply(const Selection &Inputs) {
auto &SM = Inputs.AST->getSourceManager();
std::string Replacement;
for (const syntax::Token &T : Expansion.Expanded) {
Replacement += T.text(SM);
Replacement += " ";
}
if (!Replacement.empty()) {
assert(Replacement.back() == ' ');
Replacement.pop_back();
}
CharSourceRange MacroRange =
CharSourceRange::getCharRange(Expansion.Spelled.front().location(),
Expansion.Spelled.back().endLocation());
tooling::Replacements Reps;
llvm::cantFail(Reps.add(tooling::Replacement(SM, MacroRange, Replacement)));
return Effect::mainFileEdit(SM, std::move(Reps));
}
std::string ExpandMacro::title() const {
return std::string(llvm::formatv("Expand macro '{0}'", MacroName));
}
} // namespace
} // namespace clangd
} // namespace clang