Commit 40078465 authored by Jakub Kuderski's avatar Jakub Kuderski
Browse files

[clang-tidy] Fix PR32896, PR33058: detect initializer lists in modernize-use-empalce 

Summary:
The patch is backported from: r302281 to fix the 4.0.1 release blocker PR33058.
This patch fixes [[ https://bugs.llvm.org/show_bug.cgi?id=32896 | PR32896 ]].

The problem was that modernize-use-emplace incorrectly removed changed push_back into emplace_back, removing explicit constructor call with initializer list parameter, resulting in compiler error after applying fixits.
modernize-use-emplace used to check if matched constructor had InitListExpr, but didn't check against CXXStdInitializerListExpr.

Eg.

```
std::vector<std::vector<int>> v;
  v.push_back(std::vector<int>({1})); // --> v.emplace_back({1});
```

Reviewers: Prazek, alexfh, aaron.ballman

Reviewed By: Prazek, alexfh, aaron.ballman

Subscribers: xazax.hun, cfe-commits

Tags: #clang-tools-extra

Differential Revision: https://reviews.llvm.org/D32767

llvm-svn: 303524
parent c128825c

clang-tools-extra/clang-tidy/modernize/UseEmplaceCheck.cpp

+13 −1
Original line number Diff line number Diff line
@@ -20,6 +20,14 @@ static const auto DefaultContainersWithPushBack = 
static const auto DefaultSmartPointers =

    "::std::shared_ptr; ::std::unique_ptr; ::std::auto_ptr; ::std::weak_ptr";



namespace {

namespace impl {

// FIXME: This matcher should be replaced by a matcher from ASTMatcher.h

const ast_matchers::internal::VariadicDynCastAllOfMatcher<Stmt,

    CXXStdInitializerListExpr> cxxStdInitializerListExpr;

} // namespace impl

} // namespace



UseEmplaceCheck::UseEmplaceCheck(StringRef Name, ClangTidyContext *Context)

    : ClangTidyCheck(Name, Context),

      ContainersWithPushBack(utils::options::parseStringList(Options.get(
@@ -69,7 +77,11 @@ void UseEmplaceCheck::registerMatchers(MatchFinder *Finder) { 
  // emplace_back can't access private constructor.

  auto isPrivateCtor = hasDeclaration(cxxConstructorDecl(isPrivate()));



  auto hasInitList = has(ignoringImplicit(initListExpr()));

  auto hasInitList = anyOf(has(ignoringImplicit(initListExpr())),

                           has(impl::cxxStdInitializerListExpr()));

  // FIXME: Replace internal C++ initializer list matcher with one from

  // ASTMatchers.h



  // FIXME: Discard 0/NULL (as nullptr), static inline const data members,

  // overloaded functions and template names.

  auto soughtConstructExpr =

clang-tools-extra/test/clang-tidy/modernize-use-emplace.cpp

+23 −0
Original line number Diff line number Diff line
@@ -4,9 +4,19 @@ 
// RUN:               value: '::std::vector; ::std::list; ::std::deque; llvm::LikeASmallVector'}]}" -- -std=c++11



namespace std {

template <typename>

class initializer_list

{

public:

  initializer_list() noexcept {}

};



template <typename T>

class vector {

public:

  vector() = default;

  vector(initializer_list<T>) {}



  void push_back(const T &) {}

  void push_back(T &&) {}
@@ -422,3 +432,16 @@ void testWithDtor() { 
  // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: use emplace_back

  // CHECK-FIXES: v.emplace_back(42);

}



void testInitializerList() {

  std::vector<std::vector<int>> v;

  v.push_back(std::vector<int>({1}));

  // Test against the bug reported in PR32896.



  v.push_back({{2}});



  using PairIntVector = std::pair<int, std::vector<int>>;

  std::vector<PairIntVector> x;

  x.push_back(PairIntVector(3, {4}));

  x.push_back({5, {6}});

}