Casting.cpp
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//===---------- llvm/unittest/Support/Casting.cpp - Casting tests ---------===//
//
// 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 "llvm/Support/Casting.h"
#include "llvm/IR/User.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "gtest/gtest.h"
#include <cstdlib>
namespace llvm {
// Used to test illegal cast. If a cast doesn't match any of the "real" ones,
// it will match this one.
struct IllegalCast;
template <typename T> IllegalCast *cast(...) { return nullptr; }
// set up two example classes
// with conversion facility
//
struct bar {
bar() {}
struct foo *baz();
struct foo *caz();
struct foo *daz();
struct foo *naz();
private:
bar(const bar &);
};
struct foo {
void ext() const;
/* static bool classof(const bar *X) {
cerr << "Classof: " << X << "\n";
return true;
}*/
};
struct base {
virtual ~base() {}
};
struct derived : public base {
static bool classof(const base *B) { return true; }
};
template <> struct isa_impl<foo, bar> {
static inline bool doit(const bar &Val) {
dbgs() << "Classof: " << &Val << "\n";
return true;
}
};
template <typename T> struct isa_impl<foo, T> {
static inline bool doit(const T &Val) { return false; }
};
foo *bar::baz() {
return cast<foo>(this);
}
foo *bar::caz() {
return cast_or_null<foo>(this);
}
foo *bar::daz() {
return dyn_cast<foo>(this);
}
foo *bar::naz() {
return dyn_cast_or_null<foo>(this);
}
bar *fub();
template <> struct simplify_type<foo> {
typedef int SimpleType;
static SimpleType getSimplifiedValue(foo &Val) { return 0; }
};
} // End llvm namespace
using namespace llvm;
// Test the peculiar behavior of Use in simplify_type.
static_assert(std::is_same<simplify_type<Use>::SimpleType, Value *>::value,
"Use doesn't simplify correctly!");
static_assert(std::is_same<simplify_type<Use *>::SimpleType, Value *>::value,
"Use doesn't simplify correctly!");
// Test that a regular class behaves as expected.
static_assert(std::is_same<simplify_type<foo>::SimpleType, int>::value,
"Unexpected simplify_type result!");
static_assert(std::is_same<simplify_type<foo *>::SimpleType, foo *>::value,
"Unexpected simplify_type result!");
namespace {
const foo *null_foo = nullptr;
bar B;
extern bar &B1;
bar &B1 = B;
extern const bar *B2;
// test various configurations of const
const bar &B3 = B1;
const bar *const B4 = B2;
TEST(CastingTest, isa) {
EXPECT_TRUE(isa<foo>(B1));
EXPECT_TRUE(isa<foo>(B2));
EXPECT_TRUE(isa<foo>(B3));
EXPECT_TRUE(isa<foo>(B4));
}
TEST(CastingTest, isa_and_nonnull) {
EXPECT_TRUE(isa_and_nonnull<foo>(B2));
EXPECT_TRUE(isa_and_nonnull<foo>(B4));
EXPECT_FALSE(isa_and_nonnull<foo>(fub()));
}
TEST(CastingTest, cast) {
foo &F1 = cast<foo>(B1);
EXPECT_NE(&F1, null_foo);
const foo *F3 = cast<foo>(B2);
EXPECT_NE(F3, null_foo);
const foo *F4 = cast<foo>(B2);
EXPECT_NE(F4, null_foo);
const foo &F5 = cast<foo>(B3);
EXPECT_NE(&F5, null_foo);
const foo *F6 = cast<foo>(B4);
EXPECT_NE(F6, null_foo);
// Can't pass null pointer to cast<>.
// foo *F7 = cast<foo>(fub());
// EXPECT_EQ(F7, null_foo);
foo *F8 = B1.baz();
EXPECT_NE(F8, null_foo);
std::unique_ptr<const bar> BP(B2);
auto FP = cast<foo>(std::move(BP));
static_assert(std::is_same<std::unique_ptr<const foo>, decltype(FP)>::value,
"Incorrect deduced return type!");
EXPECT_NE(FP.get(), null_foo);
FP.release();
}
TEST(CastingTest, cast_or_null) {
const foo *F11 = cast_or_null<foo>(B2);
EXPECT_NE(F11, null_foo);
const foo *F12 = cast_or_null<foo>(B2);
EXPECT_NE(F12, null_foo);
const foo *F13 = cast_or_null<foo>(B4);
EXPECT_NE(F13, null_foo);
const foo *F14 = cast_or_null<foo>(fub()); // Shouldn't print.
EXPECT_EQ(F14, null_foo);
foo *F15 = B1.caz();
EXPECT_NE(F15, null_foo);
std::unique_ptr<const bar> BP(fub());
auto FP = cast_or_null<foo>(std::move(BP));
EXPECT_EQ(FP.get(), null_foo);
}
TEST(CastingTest, dyn_cast) {
const foo *F1 = dyn_cast<foo>(B2);
EXPECT_NE(F1, null_foo);
const foo *F2 = dyn_cast<foo>(B2);
EXPECT_NE(F2, null_foo);
const foo *F3 = dyn_cast<foo>(B4);
EXPECT_NE(F3, null_foo);
// Can't pass null pointer to dyn_cast<>.
// foo *F4 = dyn_cast<foo>(fub());
// EXPECT_EQ(F4, null_foo);
foo *F5 = B1.daz();
EXPECT_NE(F5, null_foo);
}
TEST(CastingTest, dyn_cast_or_null) {
const foo *F1 = dyn_cast_or_null<foo>(B2);
EXPECT_NE(F1, null_foo);
const foo *F2 = dyn_cast_or_null<foo>(B2);
EXPECT_NE(F2, null_foo);
const foo *F3 = dyn_cast_or_null<foo>(B4);
EXPECT_NE(F3, null_foo);
foo *F4 = dyn_cast_or_null<foo>(fub());
EXPECT_EQ(F4, null_foo);
foo *F5 = B1.naz();
EXPECT_NE(F5, null_foo);
}
std::unique_ptr<derived> newd() { return std::make_unique<derived>(); }
std::unique_ptr<base> newb() { return std::make_unique<derived>(); }
TEST(CastingTest, unique_dyn_cast) {
derived *OrigD = nullptr;
auto D = std::make_unique<derived>();
OrigD = D.get();
// Converting from D to itself is valid, it should return a new unique_ptr
// and the old one should become nullptr.
auto NewD = unique_dyn_cast<derived>(D);
ASSERT_EQ(OrigD, NewD.get());
ASSERT_EQ(nullptr, D);
// Converting from D to B is valid, B should have a value and D should be
// nullptr.
auto B = unique_dyn_cast<base>(NewD);
ASSERT_EQ(OrigD, B.get());
ASSERT_EQ(nullptr, NewD);
// Converting from B to itself is valid, it should return a new unique_ptr
// and the old one should become nullptr.
auto NewB = unique_dyn_cast<base>(B);
ASSERT_EQ(OrigD, NewB.get());
ASSERT_EQ(nullptr, B);
// Converting from B to D is valid, D should have a value and B should be
// nullptr;
D = unique_dyn_cast<derived>(NewB);
ASSERT_EQ(OrigD, D.get());
ASSERT_EQ(nullptr, NewB);
// Converting between unrelated types should fail. The original value should
// remain unchanged and it should return nullptr.
auto F = unique_dyn_cast<foo>(D);
ASSERT_EQ(nullptr, F);
ASSERT_EQ(OrigD, D.get());
// All of the above should also hold for temporaries.
auto D2 = unique_dyn_cast<derived>(newd());
EXPECT_NE(nullptr, D2);
auto B2 = unique_dyn_cast<derived>(newb());
EXPECT_NE(nullptr, B2);
auto B3 = unique_dyn_cast<base>(newb());
EXPECT_NE(nullptr, B3);
auto F2 = unique_dyn_cast<foo>(newb());
EXPECT_EQ(nullptr, F2);
}
// These lines are errors...
//foo *F20 = cast<foo>(B2); // Yields const foo*
//foo &F21 = cast<foo>(B3); // Yields const foo&
//foo *F22 = cast<foo>(B4); // Yields const foo*
//foo &F23 = cast_or_null<foo>(B1);
//const foo &F24 = cast_or_null<foo>(B3);
const bar *B2 = &B;
} // anonymous namespace
bar *llvm::fub() { return nullptr; }
namespace {
namespace inferred_upcasting {
// This test case verifies correct behavior of inferred upcasts when the
// types are statically known to be OK to upcast. This is the case when,
// for example, Derived inherits from Base, and we do `isa<Base>(Derived)`.
// Note: This test will actually fail to compile without inferred
// upcasting.
class Base {
public:
// No classof. We are testing that the upcast is inferred.
Base() {}
};
class Derived : public Base {
public:
Derived() {}
};
// Even with no explicit classof() in Base, we should still be able to cast
// Derived to its base class.
TEST(CastingTest, UpcastIsInferred) {
Derived D;
EXPECT_TRUE(isa<Base>(D));
Base *BP = dyn_cast<Base>(&D);
EXPECT_TRUE(BP != nullptr);
}
// This test verifies that the inferred upcast takes precedence over an
// explicitly written one. This is important because it verifies that the
// dynamic check gets optimized away.
class UseInferredUpcast {
public:
int Dummy;
static bool classof(const UseInferredUpcast *) {
return false;
}
};
TEST(CastingTest, InferredUpcastTakesPrecedence) {
UseInferredUpcast UIU;
// Since the explicit classof() returns false, this will fail if the
// explicit one is used.
EXPECT_TRUE(isa<UseInferredUpcast>(&UIU));
}
} // end namespace inferred_upcasting
} // end anonymous namespace
// Test that we reject casts of temporaries (and so the illegal cast gets used).
namespace TemporaryCast {
struct pod {};
IllegalCast *testIllegalCast() { return cast<foo>(pod()); }
}
namespace {
namespace pointer_wrappers {
struct Base {
bool IsDerived;
Base(bool IsDerived = false) : IsDerived(IsDerived) {}
};
struct Derived : Base {
Derived() : Base(true) {}
static bool classof(const Base *B) { return B->IsDerived; }
};
class PTy {
Base *B;
public:
PTy(Base *B) : B(B) {}
explicit operator bool() const { return get(); }
Base *get() const { return B; }
};
} // end namespace pointer_wrappers
} // end namespace
namespace llvm {
template <> struct simplify_type<pointer_wrappers::PTy> {
typedef pointer_wrappers::Base *SimpleType;
static SimpleType getSimplifiedValue(pointer_wrappers::PTy &P) {
return P.get();
}
};
template <> struct simplify_type<const pointer_wrappers::PTy> {
typedef pointer_wrappers::Base *SimpleType;
static SimpleType getSimplifiedValue(const pointer_wrappers::PTy &P) {
return P.get();
}
};
} // end namespace llvm
namespace {
namespace pointer_wrappers {
// Some objects.
pointer_wrappers::Base B;
pointer_wrappers::Derived D;
// Mutable "smart" pointers.
pointer_wrappers::PTy MN(nullptr);
pointer_wrappers::PTy MB(&B);
pointer_wrappers::PTy MD(&D);
// Const "smart" pointers.
const pointer_wrappers::PTy CN(nullptr);
const pointer_wrappers::PTy CB(&B);
const pointer_wrappers::PTy CD(&D);
TEST(CastingTest, smart_isa) {
EXPECT_TRUE(!isa<pointer_wrappers::Derived>(MB));
EXPECT_TRUE(!isa<pointer_wrappers::Derived>(CB));
EXPECT_TRUE(isa<pointer_wrappers::Derived>(MD));
EXPECT_TRUE(isa<pointer_wrappers::Derived>(CD));
}
TEST(CastingTest, smart_cast) {
EXPECT_TRUE(cast<pointer_wrappers::Derived>(MD) == &D);
EXPECT_TRUE(cast<pointer_wrappers::Derived>(CD) == &D);
}
TEST(CastingTest, smart_cast_or_null) {
EXPECT_TRUE(cast_or_null<pointer_wrappers::Derived>(MN) == nullptr);
EXPECT_TRUE(cast_or_null<pointer_wrappers::Derived>(CN) == nullptr);
EXPECT_TRUE(cast_or_null<pointer_wrappers::Derived>(MD) == &D);
EXPECT_TRUE(cast_or_null<pointer_wrappers::Derived>(CD) == &D);
}
TEST(CastingTest, smart_dyn_cast) {
EXPECT_TRUE(dyn_cast<pointer_wrappers::Derived>(MB) == nullptr);
EXPECT_TRUE(dyn_cast<pointer_wrappers::Derived>(CB) == nullptr);
EXPECT_TRUE(dyn_cast<pointer_wrappers::Derived>(MD) == &D);
EXPECT_TRUE(dyn_cast<pointer_wrappers::Derived>(CD) == &D);
}
TEST(CastingTest, smart_dyn_cast_or_null) {
EXPECT_TRUE(dyn_cast_or_null<pointer_wrappers::Derived>(MN) == nullptr);
EXPECT_TRUE(dyn_cast_or_null<pointer_wrappers::Derived>(CN) == nullptr);
EXPECT_TRUE(dyn_cast_or_null<pointer_wrappers::Derived>(MB) == nullptr);
EXPECT_TRUE(dyn_cast_or_null<pointer_wrappers::Derived>(CB) == nullptr);
EXPECT_TRUE(dyn_cast_or_null<pointer_wrappers::Derived>(MD) == &D);
EXPECT_TRUE(dyn_cast_or_null<pointer_wrappers::Derived>(CD) == &D);
}
} // end namespace pointer_wrappers
} // end namespace