unittests/Support/Casting.cpp

   1 //===---------- llvm/unittest/Support/Casting.cpp - Casting tests ---------===//
   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 "llvm/Support/Casting.h"
  10 #include "llvm/IR/User.h"
  11 #include "llvm/Support/Debug.h"
  12 #include "llvm/Support/raw_ostream.h"
  13 #include "gtest/gtest.h"
  14 #include <cstdlib>
  15
  16 namespace llvm {
  17 // Used to test illegal cast. If a cast doesn't match any of the "real" ones,
  18 // it will match this one.
  19 struct IllegalCast;
  20 template <typename T> IllegalCast *cast(...) { return nullptr; }
  21
  22 // set up two example classes
  23 // with conversion facility
  24 //
  25 struct bar {
  26   bar() {}
  27   struct foo *baz();
  28   struct foo *caz();
  29   struct foo *daz();
  30   struct foo *naz();
  31 private:
  32   bar(const bar &);
  33 };
  34 struct foo {
  35   void ext() const;
  36   /*  static bool classof(const bar *X) {
  37     cerr << "Classof: " << X << "\n";
  38     return true;
  39     }*/
  40 };
  41
  42 struct base {
  43   virtual ~base() {}
  44 };
  45
  46 struct derived : public base {
  47   static bool classof(const base *B) { return true; }
  48 };
  49
  50 template <> struct isa_impl<foo, bar> {
  51   static inline bool doit(const bar &Val) {
  52     dbgs() << "Classof: " << &Val << "\n";
  53     return true;
  54   }
  55 };
  56
  57 template <typename T> struct isa_impl<foo, T> {
  58   static inline bool doit(const T &Val) { return false; }
  59 };
  60
  61 foo *bar::baz() {
  62     return cast<foo>(this);
  63 }
  64
  65 foo *bar::caz() {
  66     return cast_or_null<foo>(this);
  67 }
  68
  69 foo *bar::daz() {
  70     return dyn_cast<foo>(this);
  71 }
  72
  73 foo *bar::naz() {
  74     return dyn_cast_or_null<foo>(this);
  75 }
  76
  77
  78 bar *fub();
  79
  80 template <> struct simplify_type<foo> {
  81   typedef int SimpleType;
  82   static SimpleType getSimplifiedValue(foo &Val) { return 0; }
  83 };
  84
  85 } // End llvm namespace
  86
  87 using namespace llvm;
  88
  89
  90 // Test the peculiar behavior of Use in simplify_type.
  91 static_assert(std::is_same<simplify_type<Use>::SimpleType, Value *>::value,
  92               "Use doesn't simplify correctly!");
  93 static_assert(std::is_same<simplify_type<Use *>::SimpleType, Value *>::value,
  94               "Use doesn't simplify correctly!");
  95
  96 // Test that a regular class behaves as expected.
  97 static_assert(std::is_same<simplify_type<foo>::SimpleType, int>::value,
  98               "Unexpected simplify_type result!");
  99 static_assert(std::is_same<simplify_type<foo *>::SimpleType, foo *>::value,
 100               "Unexpected simplify_type result!");
 101
 102 namespace {
 103
 104 const foo *null_foo = nullptr;
 105
 106 bar B;
 107 extern bar &B1;
 108 bar &B1 = B;
 109 extern const bar *B2;
 110 // test various configurations of const
 111 const bar &B3 = B1;
 112 const bar *const B4 = B2;
 113
 114 TEST(CastingTest, isa) {
 115   EXPECT_TRUE(isa<foo>(B1));
 116   EXPECT_TRUE(isa<foo>(B2));
 117   EXPECT_TRUE(isa<foo>(B3));
 118   EXPECT_TRUE(isa<foo>(B4));
 119 }
 120
 121 TEST(CastingTest, isa_and_nonnull) {
 122   EXPECT_TRUE(isa_and_nonnull<foo>(B2));
 123   EXPECT_TRUE(isa_and_nonnull<foo>(B4));
 124   EXPECT_FALSE(isa_and_nonnull<foo>(fub()));
 125 }
 126
 127 TEST(CastingTest, cast) {
 128   foo &F1 = cast<foo>(B1);
 129   EXPECT_NE(&F1, null_foo);
 130   const foo *F3 = cast<foo>(B2);
 131   EXPECT_NE(F3, null_foo);
 132   const foo *F4 = cast<foo>(B2);
 133   EXPECT_NE(F4, null_foo);
 134   const foo &F5 = cast<foo>(B3);
 135   EXPECT_NE(&F5, null_foo);
 136   const foo *F6 = cast<foo>(B4);
 137   EXPECT_NE(F6, null_foo);
 138   // Can't pass null pointer to cast<>.
 139   // foo *F7 = cast<foo>(fub());
 140   // EXPECT_EQ(F7, null_foo);
 141   foo *F8 = B1.baz();
 142   EXPECT_NE(F8, null_foo);
 143
 144   std::unique_ptr<const bar> BP(B2);
 145   auto FP = cast<foo>(std::move(BP));
 146   static_assert(std::is_same<std::unique_ptr<const foo>, decltype(FP)>::value,
 147                 "Incorrect deduced return type!");
 148   EXPECT_NE(FP.get(), null_foo);
 149   FP.release();
 150 }
 151
 152 TEST(CastingTest, cast_or_null) {
 153   const foo *F11 = cast_or_null<foo>(B2);
 154   EXPECT_NE(F11, null_foo);
 155   const foo *F12 = cast_or_null<foo>(B2);
 156   EXPECT_NE(F12, null_foo);
 157   const foo *F13 = cast_or_null<foo>(B4);
 158   EXPECT_NE(F13, null_foo);
 159   const foo *F14 = cast_or_null<foo>(fub());  // Shouldn't print.
 160   EXPECT_EQ(F14, null_foo);
 161   foo *F15 = B1.caz();
 162   EXPECT_NE(F15, null_foo);
 163
 164   std::unique_ptr<const bar> BP(fub());
 165   auto FP = cast_or_null<foo>(std::move(BP));
 166   EXPECT_EQ(FP.get(), null_foo);
 167 }
 168
 169 TEST(CastingTest, dyn_cast) {
 170   const foo *F1 = dyn_cast<foo>(B2);
 171   EXPECT_NE(F1, null_foo);
 172   const foo *F2 = dyn_cast<foo>(B2);
 173   EXPECT_NE(F2, null_foo);
 174   const foo *F3 = dyn_cast<foo>(B4);
 175   EXPECT_NE(F3, null_foo);
 176   // Can't pass null pointer to dyn_cast<>.
 177   // foo *F4 = dyn_cast<foo>(fub());
 178   // EXPECT_EQ(F4, null_foo);
 179   foo *F5 = B1.daz();
 180   EXPECT_NE(F5, null_foo);
 181 }
 182
 183 TEST(CastingTest, dyn_cast_or_null) {
 184   const foo *F1 = dyn_cast_or_null<foo>(B2);
 185   EXPECT_NE(F1, null_foo);
 186   const foo *F2 = dyn_cast_or_null<foo>(B2);
 187   EXPECT_NE(F2, null_foo);
 188   const foo *F3 = dyn_cast_or_null<foo>(B4);
 189   EXPECT_NE(F3, null_foo);
 190   foo *F4 = dyn_cast_or_null<foo>(fub());
 191   EXPECT_EQ(F4, null_foo);
 192   foo *F5 = B1.naz();
 193   EXPECT_NE(F5, null_foo);
 194 }
 195
 196 std::unique_ptr<derived> newd() { return std::make_unique<derived>(); }
 197 std::unique_ptr<base> newb() { return std::make_unique<derived>(); }
 198
 199 TEST(CastingTest, unique_dyn_cast) {
 200   derived *OrigD = nullptr;
 201   auto D = std::make_unique<derived>();
 202   OrigD = D.get();
 203
 204   // Converting from D to itself is valid, it should return a new unique_ptr
 205   // and the old one should become nullptr.
 206   auto NewD = unique_dyn_cast<derived>(D);
 207   ASSERT_EQ(OrigD, NewD.get());
 208   ASSERT_EQ(nullptr, D);
 209
 210   // Converting from D to B is valid, B should have a value and D should be
 211   // nullptr.
 212   auto B = unique_dyn_cast<base>(NewD);
 213   ASSERT_EQ(OrigD, B.get());
 214   ASSERT_EQ(nullptr, NewD);
 215
 216   // Converting from B to itself is valid, it should return a new unique_ptr
 217   // and the old one should become nullptr.
 218   auto NewB = unique_dyn_cast<base>(B);
 219   ASSERT_EQ(OrigD, NewB.get());
 220   ASSERT_EQ(nullptr, B);
 221
 222   // Converting from B to D is valid, D should have a value and B should be
 223   // nullptr;
 224   D = unique_dyn_cast<derived>(NewB);
 225   ASSERT_EQ(OrigD, D.get());
 226   ASSERT_EQ(nullptr, NewB);
 227
 228   // Converting between unrelated types should fail.  The original value should
 229   // remain unchanged and it should return nullptr.
 230   auto F = unique_dyn_cast<foo>(D);
 231   ASSERT_EQ(nullptr, F);
 232   ASSERT_EQ(OrigD, D.get());
 233
 234   // All of the above should also hold for temporaries.
 235   auto D2 = unique_dyn_cast<derived>(newd());
 236   EXPECT_NE(nullptr, D2);
 237
 238   auto B2 = unique_dyn_cast<derived>(newb());
 239   EXPECT_NE(nullptr, B2);
 240
 241   auto B3 = unique_dyn_cast<base>(newb());
 242   EXPECT_NE(nullptr, B3);
 243
 244   auto F2 = unique_dyn_cast<foo>(newb());
 245   EXPECT_EQ(nullptr, F2);
 246 }
 247
 248 // These lines are errors...
 249 //foo *F20 = cast<foo>(B2);  // Yields const foo*
 250 //foo &F21 = cast<foo>(B3);  // Yields const foo&
 251 //foo *F22 = cast<foo>(B4);  // Yields const foo*
 252 //foo &F23 = cast_or_null<foo>(B1);
 253 //const foo &F24 = cast_or_null<foo>(B3);
 254
 255 const bar *B2 = &B;
 256 }  // anonymous namespace
 257
 258 bar *llvm::fub() { return nullptr; }
 259
 260 namespace {
 261 namespace inferred_upcasting {
 262 // This test case verifies correct behavior of inferred upcasts when the
 263 // types are statically known to be OK to upcast. This is the case when,
 264 // for example, Derived inherits from Base, and we do `isa<Base>(Derived)`.
 265
 266 // Note: This test will actually fail to compile without inferred
 267 // upcasting.
 268
 269 class Base {
 270 public:
 271   // No classof. We are testing that the upcast is inferred.
 272   Base() {}
 273 };
 274
 275 class Derived : public Base {
 276 public:
 277   Derived() {}
 278 };
 279
 280 // Even with no explicit classof() in Base, we should still be able to cast
 281 // Derived to its base class.
 282 TEST(CastingTest, UpcastIsInferred) {
 283   Derived D;
 284   EXPECT_TRUE(isa<Base>(D));
 285   Base *BP = dyn_cast<Base>(&D);
 286   EXPECT_TRUE(BP != nullptr);
 287 }
 288
 289
 290 // This test verifies that the inferred upcast takes precedence over an
 291 // explicitly written one. This is important because it verifies that the
 292 // dynamic check gets optimized away.
 293 class UseInferredUpcast {
 294 public:
 295   int Dummy;
 296   static bool classof(const UseInferredUpcast *) {
 297     return false;
 298   }
 299 };
 300
 301 TEST(CastingTest, InferredUpcastTakesPrecedence) {
 302   UseInferredUpcast UIU;
 303   // Since the explicit classof() returns false, this will fail if the
 304   // explicit one is used.
 305   EXPECT_TRUE(isa<UseInferredUpcast>(&UIU));
 306 }
 307
 308 } // end namespace inferred_upcasting
 309 } // end anonymous namespace
 310 // Test that we reject casts of temporaries (and so the illegal cast gets used).
 311 namespace TemporaryCast {
 312 struct pod {};
 313 IllegalCast *testIllegalCast() { return cast<foo>(pod()); }
 314 }
 315
 316 namespace {
 317 namespace pointer_wrappers {
 318
 319 struct Base {
 320   bool IsDerived;
 321   Base(bool IsDerived = false) : IsDerived(IsDerived) {}
 322 };
 323
 324 struct Derived : Base {
 325   Derived() : Base(true) {}
 326   static bool classof(const Base *B) { return B->IsDerived; }
 327 };
 328
 329 class PTy {
 330   Base *B;
 331 public:
 332   PTy(Base *B) : B(B) {}
 333   explicit operator bool() const { return get(); }
 334   Base *get() const { return B; }
 335 };
 336
 337 } // end namespace pointer_wrappers
 338 } // end namespace
 339
 340 namespace llvm {
 341
 342 template <> struct simplify_type<pointer_wrappers::PTy> {
 343   typedef pointer_wrappers::Base *SimpleType;
 344   static SimpleType getSimplifiedValue(pointer_wrappers::PTy &P) {
 345     return P.get();
 346   }
 347 };
 348 template <> struct simplify_type<const pointer_wrappers::PTy> {
 349   typedef pointer_wrappers::Base *SimpleType;
 350   static SimpleType getSimplifiedValue(const pointer_wrappers::PTy &P) {
 351     return P.get();
 352   }
 353 };
 354
 355 } // end namespace llvm
 356
 357 namespace {
 358 namespace pointer_wrappers {
 359
 360 // Some objects.
 361 pointer_wrappers::Base B;
 362 pointer_wrappers::Derived D;
 363
 364 // Mutable "smart" pointers.
 365 pointer_wrappers::PTy MN(nullptr);
 366 pointer_wrappers::PTy MB(&B);
 367 pointer_wrappers::PTy MD(&D);
 368
 369 // Const "smart" pointers.
 370 const pointer_wrappers::PTy CN(nullptr);
 371 const pointer_wrappers::PTy CB(&B);
 372 const pointer_wrappers::PTy CD(&D);
 373
 374 TEST(CastingTest, smart_isa) {
 375   EXPECT_TRUE(!isa<pointer_wrappers::Derived>(MB));
 376   EXPECT_TRUE(!isa<pointer_wrappers::Derived>(CB));
 377   EXPECT_TRUE(isa<pointer_wrappers::Derived>(MD));
 378   EXPECT_TRUE(isa<pointer_wrappers::Derived>(CD));
 379 }
 380
 381 TEST(CastingTest, smart_cast) {
 382   EXPECT_TRUE(cast<pointer_wrappers::Derived>(MD) == &D);
 383   EXPECT_TRUE(cast<pointer_wrappers::Derived>(CD) == &D);
 384 }
 385
 386 TEST(CastingTest, smart_cast_or_null) {
 387   EXPECT_TRUE(cast_or_null<pointer_wrappers::Derived>(MN) == nullptr);
 388   EXPECT_TRUE(cast_or_null<pointer_wrappers::Derived>(CN) == nullptr);
 389   EXPECT_TRUE(cast_or_null<pointer_wrappers::Derived>(MD) == &D);
 390   EXPECT_TRUE(cast_or_null<pointer_wrappers::Derived>(CD) == &D);
 391 }
 392
 393 TEST(CastingTest, smart_dyn_cast) {
 394   EXPECT_TRUE(dyn_cast<pointer_wrappers::Derived>(MB) == nullptr);
 395   EXPECT_TRUE(dyn_cast<pointer_wrappers::Derived>(CB) == nullptr);
 396   EXPECT_TRUE(dyn_cast<pointer_wrappers::Derived>(MD) == &D);
 397   EXPECT_TRUE(dyn_cast<pointer_wrappers::Derived>(CD) == &D);
 398 }
 399
 400 TEST(CastingTest, smart_dyn_cast_or_null) {
 401   EXPECT_TRUE(dyn_cast_or_null<pointer_wrappers::Derived>(MN) == nullptr);
 402   EXPECT_TRUE(dyn_cast_or_null<pointer_wrappers::Derived>(CN) == nullptr);
 403   EXPECT_TRUE(dyn_cast_or_null<pointer_wrappers::Derived>(MB) == nullptr);
 404   EXPECT_TRUE(dyn_cast_or_null<pointer_wrappers::Derived>(CB) == nullptr);
 405   EXPECT_TRUE(dyn_cast_or_null<pointer_wrappers::Derived>(MD) == &D);
 406   EXPECT_TRUE(dyn_cast_or_null<pointer_wrappers::Derived>(CD) == &D);
 407 }
 408
 409 } // end namespace pointer_wrappers
 410 } // end namespace