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| //===--- DefineInline.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 "AST.h"
#include "FindTarget.h"
#include "Logger.h"
#include "Selection.h"
#include "SourceCode.h"
#include "XRefs.h"
#include "refactor/Tweak.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/ASTTypeTraits.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclBase.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/NestedNameSpecifier.h"
#include "clang/AST/PrettyPrinter.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/AST/Stmt.h"
#include "clang/AST/TemplateBase.h"
#include "clang/AST/Type.h"
#include "clang/AST/TypeLoc.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TokenKinds.h"
#include "clang/Index/IndexDataConsumer.h"
#include "clang/Index/IndexSymbol.h"
#include "clang/Index/IndexingAction.h"
#include "clang/Lex/Lexer.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Lex/Token.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/Sema.h"
#include "clang/Tooling/Core/Replacement.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/FormatAdapters.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/raw_ostream.h"
#include <cstddef>
#include <set>
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>
namespace clang {
namespace clangd {
namespace {
// Returns semicolon location for the given FD. Since AST doesn't contain that
// information, searches for a semicolon by lexing from end of function decl
// while skipping comments.
llvm::Optional<SourceLocation> getSemicolonForDecl(const FunctionDecl *FD) {
const SourceManager &SM = FD->getASTContext().getSourceManager();
const LangOptions &LangOpts = FD->getASTContext().getLangOpts();
SourceLocation CurLoc = FD->getEndLoc();
auto NextTok = Lexer::findNextToken(CurLoc, SM, LangOpts);
if (!NextTok || !NextTok->is(tok::semi))
return llvm::None;
return NextTok->getLocation();
}
// Deduces the FunctionDecl from a selection. Requires either the function body
// or the function decl to be selected. Returns null if none of the above
// criteria is met.
const FunctionDecl *getSelectedFunction(const SelectionTree::Node *SelNode) {
const ast_type_traits::DynTypedNode &AstNode = SelNode->ASTNode;
if (const FunctionDecl *FD = AstNode.get<FunctionDecl>())
return FD;
if (AstNode.get<CompoundStmt>() &&
SelNode->Selected == SelectionTree::Complete) {
if (const SelectionTree::Node *P = SelNode->Parent)
return P->ASTNode.get<FunctionDecl>();
}
return nullptr;
}
// Checks the decls mentioned in Source are visible in the context of Target.
// Achives that by checking declaraions occur before target location in
// translation unit or declared in the same class.
bool checkDeclsAreVisible(const llvm::DenseSet<const Decl *> &DeclRefs,
const FunctionDecl *Target, const SourceManager &SM) {
SourceLocation TargetLoc = Target->getLocation();
// To be used in visibility check below, decls in a class are visible
// independent of order.
const RecordDecl *Class = nullptr;
if (const auto *MD = llvm::dyn_cast<CXXMethodDecl>(Target))
Class = MD->getParent();
for (const auto *DR : DeclRefs) {
// Use canonical decl, since having one decl before target is enough.
const Decl *D = DR->getCanonicalDecl();
if (D == Target)
continue;
SourceLocation DeclLoc = D->getLocation();
// FIXME: Allow declarations from different files with include insertion.
if (!SM.isWrittenInSameFile(DeclLoc, TargetLoc))
return false;
// If declaration is before target, then it is visible.
if (SM.isBeforeInTranslationUnit(DeclLoc, TargetLoc))
continue;
// Otherwise they need to be in same class
if (!Class)
return false;
const RecordDecl *Parent = nullptr;
if (const auto *MD = llvm::dyn_cast<CXXMethodDecl>(D))
Parent = MD->getParent();
else if (const auto *FD = llvm::dyn_cast<FieldDecl>(D))
Parent = FD->getParent();
if (Parent != Class)
return false;
}
return true;
}
// Rewrites body of FD to fully-qualify all of the decls inside.
llvm::Expected<std::string> qualifyAllDecls(const FunctionDecl *FD) {
// There are three types of spellings that needs to be qualified in a function
// body:
// - Types: Foo -> ns::Foo
// - DeclRefExpr: ns2::foo() -> ns1::ns2::foo();
// - UsingDecls:
// using ns2::foo -> using ns1::ns2::foo
// using namespace ns2 -> using namespace ns1::ns2
// using ns3 = ns2 -> using ns3 = ns1::ns2
//
// Go over all references inside a function body to generate replacements that
// will fully qualify those. So that body can be moved into an arbitrary file.
// We perform the qualification by qualyfying the first type/decl in a
// (un)qualified name. e.g:
// namespace a { namespace b { class Bar{}; void foo(); } }
// b::Bar x; -> a::b::Bar x;
// foo(); -> a::b::foo();
// FIXME: Instead of fully qualyfying we should try deducing visible scopes at
// target location and generate minimal edits.
const SourceManager &SM = FD->getASTContext().getSourceManager();
tooling::Replacements Replacements;
bool HadErrors = false;
findExplicitReferences(FD->getBody(), [&](ReferenceLoc Ref) {
// Since we want to qualify only the first qualifier, skip names with a
// qualifier.
if (Ref.Qualifier)
return;
// There might be no decl in dependent contexts, there's nothing much we can
// do in such cases.
if (Ref.Targets.empty())
return;
// Do not qualify names introduced by macro expansions.
if (Ref.NameLoc.isMacroID())
return;
for (const NamedDecl *ND : Ref.Targets) {
if (ND->getDeclContext() != Ref.Targets.front()->getDeclContext()) {
elog("define inline: Targets from multiple contexts: {0}, {1}",
printQualifiedName(*Ref.Targets.front()), printQualifiedName(*ND));
HadErrors = true;
return;
}
}
// All Targets are in the same scope, so we can safely chose first one.
const NamedDecl *ND = Ref.Targets.front();
// Skip anything from a non-namespace scope, these can be:
// - Function or Method scopes, which means decl is local and doesn't need
// qualification.
// - From Class/Struct/Union scope, which again doesn't need any qualifiers,
// rather the left side of it requires qualification, like:
// namespace a { class Bar { public: static int x; } }
// void foo() { Bar::x; }
// ~~~~~ -> we need to qualify Bar not x.
if (!ND->getDeclContext()->isNamespace())
return;
std::string Qualifier = printNamespaceScope(*ND->getDeclContext());
if (auto Err = Replacements.add(
tooling::Replacement(SM, Ref.NameLoc, 0, Qualifier))) {
HadErrors = true;
elog("define inline: Failed to add quals: {0}", std::move(Err));
}
});
if (HadErrors) {
return llvm::createStringError(
llvm::inconvertibleErrorCode(),
"define inline: Failed to compute qualifiers see logs for details.");
}
// Get new begin and end positions for the qualified body.
auto OrigBodyRange = toHalfOpenFileRange(
SM, FD->getASTContext().getLangOpts(), FD->getBody()->getSourceRange());
if (!OrigBodyRange)
return llvm::createStringError(llvm::inconvertibleErrorCode(),
"Couldn't get range func body.");
unsigned BodyBegin = SM.getFileOffset(OrigBodyRange->getBegin());
unsigned BodyEnd = Replacements.getShiftedCodePosition(
SM.getFileOffset(OrigBodyRange->getEnd()));
// Trim the result to function body.
auto QualifiedFunc = tooling::applyAllReplacements(
SM.getBufferData(SM.getFileID(OrigBodyRange->getBegin())), Replacements);
if (!QualifiedFunc)
return QualifiedFunc.takeError();
return QualifiedFunc->substr(BodyBegin, BodyEnd - BodyBegin + 1);
}
// Returns the canonical declaration for the given FunctionDecl. This will
// usually be the first declaration in current translation unit with the
// exception of template specialization.
// For those we return first declaration different than the canonical one.
// Because canonical declaration points to template decl instead of
// specialization.
const FunctionDecl *findTarget(const FunctionDecl *FD) {
auto CanonDecl = FD->getCanonicalDecl();
if (!FD->isFunctionTemplateSpecialization())
return CanonDecl;
// For specializations CanonicalDecl is the TemplatedDecl, which is not the
// target we want to inline into. Instead we traverse previous decls to find
// the first forward decl for this specialization.
auto PrevDecl = FD;
while (PrevDecl->getPreviousDecl() != CanonDecl) {
PrevDecl = PrevDecl->getPreviousDecl();
assert(PrevDecl && "Found specialization without template decl");
}
return PrevDecl;
}
// Returns the begining location for a FunctionDecl. Returns location of
// template keyword for templated functions.
const SourceLocation getBeginLoc(const FunctionDecl *FD) {
// Include template parameter list.
if (auto *FTD = FD->getDescribedFunctionTemplate())
return FTD->getBeginLoc();
return FD->getBeginLoc();
}
/// Moves definition of a function/method to its declaration location.
/// Before:
/// a.h:
/// void foo();
///
/// a.cc:
/// void foo() { return; }
///
/// ------------------------
/// After:
/// a.h:
/// void foo() { return; }
///
/// a.cc:
///
class DefineInline : public Tweak {
public:
const char *id() const override final;
Intent intent() const override { return Intent::Refactor; }
std::string title() const override {
return "Move function body to declaration";
}
// Returns true when selection is on a function definition that does not
// make use of any internal symbols.
bool prepare(const Selection &Sel) override {
const SelectionTree::Node *SelNode = Sel.ASTSelection.commonAncestor();
if (!SelNode)
return false;
Source = getSelectedFunction(SelNode);
if (!Source || !Source->isThisDeclarationADefinition())
return false;
// Only the last level of template parameter locations are not kept in AST,
// so if we are inlining a method that is in a templated class, there is no
// way to verify template parameter names. Therefore we bail out.
if (auto *MD = llvm::dyn_cast<CXXMethodDecl>(Source)) {
if (MD->getParent()->isTemplated())
return false;
}
// If function body starts or ends inside a macro, we refuse to move it into
// declaration location.
if (Source->getBody()->getBeginLoc().isMacroID() ||
Source->getBody()->getEndLoc().isMacroID())
return false;
Target = findTarget(Source);
if (Target == Source) {
// The only declaration is Source. No other declaration to move function
// body.
// FIXME: If we are in an implementation file, figure out a suitable
// location to put declaration. Possibly using other declarations in the
// AST.
return false;
}
// Check if the decls referenced in function body are visible in the
// declaration location.
if (!checkDeclsAreVisible(getNonLocalDeclRefs(Sel.AST, Source), Target,
Sel.AST.getSourceManager()))
return false;
return true;
}
Expected<Effect> apply(const Selection &Sel) override {
const auto &AST = Sel.AST.getASTContext();
const auto &SM = AST.getSourceManager();
auto Semicolon = getSemicolonForDecl(Target);
if (!Semicolon) {
return llvm::createStringError(
llvm::inconvertibleErrorCode(),
"Couldn't find semicolon for target declaration.");
}
auto QualifiedBody = qualifyAllDecls(Source);
if (!QualifiedBody)
return QualifiedBody.takeError();
const tooling::Replacement SemicolonToFuncBody(SM, *Semicolon, 1,
*QualifiedBody);
auto DefRange = toHalfOpenFileRange(
SM, AST.getLangOpts(),
SM.getExpansionRange(CharSourceRange::getCharRange(getBeginLoc(Source),
Source->getEndLoc()))
.getAsRange());
if (!DefRange) {
return llvm::createStringError(llvm::inconvertibleErrorCode(),
"Couldn't get range for the source.");
}
unsigned int SourceLen = SM.getFileOffset(DefRange->getEnd()) -
SM.getFileOffset(DefRange->getBegin());
const tooling::Replacement DeleteFuncBody(SM, DefRange->getBegin(),
SourceLen, "");
llvm::SmallVector<std::pair<std::string, Edit>, 2> Edits;
// Edit for Target.
auto FE = Effect::fileEdit(SM, SM.getFileID(*Semicolon),
tooling::Replacements(SemicolonToFuncBody));
if (!FE)
return FE.takeError();
Edits.push_back(std::move(*FE));
// Edit for Source.
if (!SM.isWrittenInSameFile(DefRange->getBegin(),
SM.getExpansionLoc(Target->getBeginLoc()))) {
// Generate a new edit if the Source and Target are in different files.
auto FE = Effect::fileEdit(SM, SM.getFileID(Sel.Cursor),
tooling::Replacements(DeleteFuncBody));
if (!FE)
return FE.takeError();
Edits.push_back(std::move(*FE));
} else {
// Merge with previous edit if they are in the same file.
if (auto Err = Edits.front().second.Replacements.add(DeleteFuncBody))
return std::move(Err);
}
Effect E;
for (auto &Pair : Edits)
E.ApplyEdits.try_emplace(std::move(Pair.first), std::move(Pair.second));
return E;
}
private:
const FunctionDecl *Source = nullptr;
const FunctionDecl *Target = nullptr;
};
REGISTER_TWEAK(DefineInline)
} // namespace
} // namespace clangd
} // namespace clang
|