Casting.cpp revision cd81d94322a39503e4a3e87b6ee03d4fcb3465fb 
1//===---------- llvm/unittest/Support/Casting.cpp - Casting tests ---------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#include "llvm/Support/Casting.h"
11#include "llvm/IR/User.h"
12#include "llvm/Support/Debug.h"
13#include "llvm/Support/raw_ostream.h"
14#include "gtest/gtest.h"
15#include <cstdlib>
16
17namespace llvm {
18// Used to test illegal cast. If a cast doesn't match any of the "real" ones,
19// it will match this one.
20struct IllegalCast;
21template <typename T> IllegalCast *cast(...) { return nullptr; }
22
23// set up two example classes
24// with conversion facility
25//
26struct bar {
27  bar() {}
28  struct foo *baz();
29  struct foo *caz();
30  struct foo *daz();
31  struct foo *naz();
32private:
33  bar(const bar &);
34};
35struct foo {
36  void ext() const;
37  /*  static bool classof(const bar *X) {
38    cerr << "Classof: " << X << "\n";
39    return true;
40    }*/
41};
42
43template <> struct isa_impl<foo, bar> {
44  static inline bool doit(const bar &Val) {
45    dbgs() << "Classof: " << &Val << "\n";
46    return true;
47  }
48};
49
50foo *bar::baz() {
51    return cast<foo>(this);
52}
53
54foo *bar::caz() {
55    return cast_or_null<foo>(this);
56}
57
58foo *bar::daz() {
59    return dyn_cast<foo>(this);
60}
61
62foo *bar::naz() {
63    return dyn_cast_or_null<foo>(this);
64}
65
66
67bar *fub();
68
69template <> struct simplify_type<foo> {
70  typedef int SimpleType;
71  static SimpleType getSimplifiedValue(foo &Val) { return 0; }
72};
73
74} // End llvm namespace
75
76using namespace llvm;
77
78
79// Test the peculiar behavior of Use in simplify_type.
80static_assert(std::is_same<simplify_type<Use>::SimpleType, Value *>::value,
81              "Use doesn't simplify correctly!");
82static_assert(std::is_same<simplify_type<Use *>::SimpleType, Value *>::value,
83              "Use doesn't simplify correctly!");
84
85// Test that a regular class behaves as expected.
86static_assert(std::is_same<simplify_type<foo>::SimpleType, int>::value,
87              "Unexpected simplify_type result!");
88static_assert(std::is_same<simplify_type<foo *>::SimpleType, foo *>::value,
89              "Unexpected simplify_type result!");
90
91namespace {
92
93const foo *null_foo = nullptr;
94
95bar B;
96extern bar &B1;
97bar &B1 = B;
98extern const bar *B2;
99// test various configurations of const
100const bar &B3 = B1;
101const bar *const B4 = B2;
102
103TEST(CastingTest, isa) {
104  EXPECT_TRUE(isa<foo>(B1));
105  EXPECT_TRUE(isa<foo>(B2));
106  EXPECT_TRUE(isa<foo>(B3));
107  EXPECT_TRUE(isa<foo>(B4));
108}
109
110TEST(CastingTest, cast) {
111  foo &F1 = cast<foo>(B1);
112  EXPECT_NE(&F1, null_foo);
113  const foo *F3 = cast<foo>(B2);
114  EXPECT_NE(F3, null_foo);
115  const foo *F4 = cast<foo>(B2);
116  EXPECT_NE(F4, null_foo);
117  const foo &F5 = cast<foo>(B3);
118  EXPECT_NE(&F5, null_foo);
119  const foo *F6 = cast<foo>(B4);
120  EXPECT_NE(F6, null_foo);
121  // Can't pass null pointer to cast<>.
122  // foo *F7 = cast<foo>(fub());
123  // EXPECT_EQ(F7, null_foo);
124  foo *F8 = B1.baz();
125  EXPECT_NE(F8, null_foo);
126}
127
128TEST(CastingTest, cast_or_null) {
129  const foo *F11 = cast_or_null<foo>(B2);
130  EXPECT_NE(F11, null_foo);
131  const foo *F12 = cast_or_null<foo>(B2);
132  EXPECT_NE(F12, null_foo);
133  const foo *F13 = cast_or_null<foo>(B4);
134  EXPECT_NE(F13, null_foo);
135  const foo *F14 = cast_or_null<foo>(fub());  // Shouldn't print.
136  EXPECT_EQ(F14, null_foo);
137  foo *F15 = B1.caz();
138  EXPECT_NE(F15, null_foo);
139}
140
141TEST(CastingTest, dyn_cast) {
142  const foo *F1 = dyn_cast<foo>(B2);
143  EXPECT_NE(F1, null_foo);
144  const foo *F2 = dyn_cast<foo>(B2);
145  EXPECT_NE(F2, null_foo);
146  const foo *F3 = dyn_cast<foo>(B4);
147  EXPECT_NE(F3, null_foo);
148  // Can't pass null pointer to dyn_cast<>.
149  // foo *F4 = dyn_cast<foo>(fub());
150  // EXPECT_EQ(F4, null_foo);
151  foo *F5 = B1.daz();
152  EXPECT_NE(F5, null_foo);
153}
154
155TEST(CastingTest, dyn_cast_or_null) {
156  const foo *F1 = dyn_cast_or_null<foo>(B2);
157  EXPECT_NE(F1, null_foo);
158  const foo *F2 = dyn_cast_or_null<foo>(B2);
159  EXPECT_NE(F2, null_foo);
160  const foo *F3 = dyn_cast_or_null<foo>(B4);
161  EXPECT_NE(F3, null_foo);
162  foo *F4 = dyn_cast_or_null<foo>(fub());
163  EXPECT_EQ(F4, null_foo);
164  foo *F5 = B1.naz();
165  EXPECT_NE(F5, null_foo);
166}
167
168// These lines are errors...
169//foo *F20 = cast<foo>(B2);  // Yields const foo*
170//foo &F21 = cast<foo>(B3);  // Yields const foo&
171//foo *F22 = cast<foo>(B4);  // Yields const foo*
172//foo &F23 = cast_or_null<foo>(B1);
173//const foo &F24 = cast_or_null<foo>(B3);
174
175const bar *B2 = &B;
176}  // anonymous namespace
177
178bar *llvm::fub() { return nullptr; }
179
180namespace {
181namespace inferred_upcasting {
182// This test case verifies correct behavior of inferred upcasts when the
183// types are statically known to be OK to upcast. This is the case when,
184// for example, Derived inherits from Base, and we do `isa<Base>(Derived)`.
185
186// Note: This test will actually fail to compile without inferred
187// upcasting.
188
189class Base {
190public:
191  // No classof. We are testing that the upcast is inferred.
192  Base() {}
193};
194
195class Derived : public Base {
196public:
197  Derived() {}
198};
199
200// Even with no explicit classof() in Base, we should still be able to cast
201// Derived to its base class.
202TEST(CastingTest, UpcastIsInferred) {
203  Derived D;
204  EXPECT_TRUE(isa<Base>(D));
205  Base *BP = dyn_cast<Base>(&D);
206  EXPECT_TRUE(BP != nullptr);
207}
208
209
210// This test verifies that the inferred upcast takes precedence over an
211// explicitly written one. This is important because it verifies that the
212// dynamic check gets optimized away.
213class UseInferredUpcast {
214public:
215  int Dummy;
216  static bool classof(const UseInferredUpcast *) {
217    return false;
218  }
219};
220
221TEST(CastingTest, InferredUpcastTakesPrecedence) {
222  UseInferredUpcast UIU;
223  // Since the explicit classof() returns false, this will fail if the
224  // explicit one is used.
225  EXPECT_TRUE(isa<UseInferredUpcast>(&UIU));
226}
227
228} // end namespace inferred_upcasting
229} // end anonymous namespace
230// Test that we reject casts of temporaries (and so the illegal cast gets used).
231namespace TemporaryCast {
232struct pod {};
233IllegalCast *testIllegalCast() { return cast<foo>(pod()); }
234}
235