From: Pete Cooper Date: Wed, 29 Jul 2015 22:19:09 +0000 (+0000) Subject: Reapply "Add reverse(ContainerTy) range adapter." X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=639ec3da92ac9b20cd1e5cb4ab235df51e167641;p=oota-llvm.git Reapply "Add reverse(ContainerTy) range adapter." This reverts commit r243567, which ultimately reapplies r243563. The fix here was to use std::enable_if for overload resolution. Thanks to David Blaikie for lots of help on this, and for the extra tests! Original commit message follows: For cases where we needed a foreach loop in reverse over a container, we had to do something like for (const GlobalValue *GV : make_range(TypeInfos.rbegin(), TypeInfos.rend())) { This provides a convenience method which shortens this to for (const GlobalValue *GV : reverse(TypeInfos)) { There are 2 versions of this, with a preference to the rbegin() version. The first uses rbegin() and rend() to construct an iterator_range. The second constructs an iterator_range from the begin() and end() methods wrapped in std::reverse_iterator's. Reviewed by David Blaikie. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243581 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/include/llvm/ADT/STLExtras.h b/include/llvm/ADT/STLExtras.h index b68345a1dcf..fa2a90680d3 100644 --- a/include/llvm/ADT/STLExtras.h +++ b/include/llvm/ADT/STLExtras.h @@ -196,6 +196,41 @@ inline mapped_iterator map_iterator(const ItTy &I, FuncTy F) { return mapped_iterator(I, F); } +/// \brief Metafunction to determine if type T has a member called rbegin(). +template struct has_rbegin { + template static char(&f(const U &, decltype(&U::rbegin)))[1]; + static char(&f(...))[2]; + const static bool value = sizeof(f(std::declval(), nullptr)) == 1; +}; + +// Returns an iterator_range over the given container which iterates in reverse. +// Note that the container must have rbegin()/rend() methods for this to work. +template +auto reverse(ContainerTy &&C, + typename std::enable_if::value>::type * = + nullptr) -> decltype(make_range(C.rbegin(), C.rend())) { + return make_range(C.rbegin(), C.rend()); +} + +// Returns a std::reverse_iterator wrapped around the given iterator. +template +std::reverse_iterator make_reverse_iterator(IteratorTy It) { + return std::reverse_iterator(It); +} + +// Returns an iterator_range over the given container which iterates in reverse. +// Note that the container must have begin()/end() methods which return +// bidirectional iterators for this to work. +template +auto reverse( + ContainerTy &&C, + typename std::enable_if::value>::type * = nullptr) + -> decltype(make_range(make_reverse_iterator(std::end(C)), + make_reverse_iterator(std::begin(C)))) { + return make_range(make_reverse_iterator(std::end(C)), + make_reverse_iterator(std::begin(C))); +} + //===----------------------------------------------------------------------===// // Extra additions to //===----------------------------------------------------------------------===// diff --git a/lib/CodeGen/AsmPrinter/ARMException.cpp b/lib/CodeGen/AsmPrinter/ARMException.cpp index 5f91763f27b..462e5d19c8d 100644 --- a/lib/CodeGen/AsmPrinter/ARMException.cpp +++ b/lib/CodeGen/AsmPrinter/ARMException.cpp @@ -115,8 +115,7 @@ void ARMException::emitTypeInfos(unsigned TTypeEncoding) { Entry = TypeInfos.size(); } - for (const GlobalValue *GV : make_range(TypeInfos.rbegin(), - TypeInfos.rend())) { + for (const GlobalValue *GV : reverse(TypeInfos)) { if (VerboseAsm) Asm->OutStreamer->AddComment("TypeInfo " + Twine(Entry--)); Asm->EmitTTypeReference(GV, TTypeEncoding); diff --git a/unittests/ADT/CMakeLists.txt b/unittests/ADT/CMakeLists.txt index cbcb0848556..cb878c61b85 100644 --- a/unittests/ADT/CMakeLists.txt +++ b/unittests/ADT/CMakeLists.txt @@ -28,6 +28,7 @@ set(ADTSources PointerIntPairTest.cpp PointerUnionTest.cpp PostOrderIteratorTest.cpp + RangeAdapterTest.cpp SCCIteratorTest.cpp SmallPtrSetTest.cpp SmallStringTest.cpp diff --git a/unittests/ADT/RangeAdapterTest.cpp b/unittests/ADT/RangeAdapterTest.cpp new file mode 100644 index 00000000000..634f5bb990d --- /dev/null +++ b/unittests/ADT/RangeAdapterTest.cpp @@ -0,0 +1,83 @@ +//===- RangeAdapterTest.cpp - Unit tests for range adapters --------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#include "llvm/ADT/iterator_range.h" +#include "llvm/ADT/STLExtras.h" +#include "gtest/gtest.h" + +#include +#include +#include + +using namespace llvm; + +namespace { + +// A wrapper around vector which exposes rbegin(), rend(). +class ReverseOnlyVector { + std::vector Vec; + +public: + ReverseOnlyVector(std::initializer_list list) : Vec(list) {} + + typedef std::vector::reverse_iterator reverse_iterator; + reverse_iterator rbegin() { return Vec.rbegin(); } + reverse_iterator rend() { return Vec.rend(); } +}; + +// A wrapper around vector which exposes begin(), end(), rbegin() and rend(). +// begin() and end() don't have implementations as this ensures that we will +// get a linker error if reverse() chooses begin()/end() over rbegin(), rend(). +class BidirectionalVector { + std::vector Vec; + +public: + BidirectionalVector(std::initializer_list list) : Vec(list) {} + + typedef std::vector::iterator iterator; + iterator begin(); + iterator end(); + + typedef std::vector::reverse_iterator reverse_iterator; + reverse_iterator rbegin() { return Vec.rbegin(); } + reverse_iterator rend() { return Vec.rend(); } +}; + +template void TestRev(const R &r) { + int counter = 3; + for (int i : r) + EXPECT_EQ(i, counter--); +} + +// Test fixture +template class RangeAdapterLValueTest : public ::testing::Test {}; + +typedef ::testing::Types, std::list, int[4]> + RangeAdapterLValueTestTypes; +TYPED_TEST_CASE(RangeAdapterLValueTest, RangeAdapterLValueTestTypes); + +TYPED_TEST(RangeAdapterLValueTest, TrivialOperation) { + TypeParam v = {0, 1, 2, 3}; + TestRev(reverse(v)); + + const TypeParam c = {0, 1, 2, 3}; + TestRev(reverse(c)); +} + +template struct RangeAdapterRValueTest : testing::Test {}; + +typedef ::testing::Types, std::list, ReverseOnlyVector, + BidirectionalVector> RangeAdapterRValueTestTypes; +TYPED_TEST_CASE(RangeAdapterRValueTest, RangeAdapterRValueTestTypes); + +TYPED_TEST(RangeAdapterRValueTest, TrivialOperation) { + TestRev(reverse(TypeParam({0, 1, 2, 3}))); +} + +} // anonymous namespace