llvm-6502/unittests/Support/Casting.cpp
Sean Silva 8b8fa7b2f4 Casting.h: Automatically handle isa<Base>(Derived).
Additionally, all such cases are handled with no dynamic check.

All `classof()` of the form

    class Foo {
      [...]
      static bool classof(const Bar *) { return true; }
      [...]
    }

where Foo is an ancestor of Bar are no longer necessary.
Don't write them!

Note: The exact test is `is_base_of<Foo, Bar>`, which is non-strict, so
that Foo is considered an ancestor of itself.

This leads to the following rule of thumb for LLVM-style RTTI:

    The argument type of `classof()` should be a strict ancestor.

For more information about implementing LLVM-style RTTI, see
docs/HowToSetUpLLVMStyleRTTI.rst

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165765 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-11 23:30:40 +00:00

207 lines
4.8 KiB
C++

//===---------- llvm/unittest/Support/Casting.cpp - Casting tests ---------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/Casting.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "gtest/gtest.h"
#include <cstdlib>
namespace llvm {
// 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;
}*/
};
template <> struct isa_impl<foo, bar> {
static inline bool doit(const bar &Val) {
dbgs() << "Classof: " << &Val << "\n";
return true;
}
};
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();
} // End llvm namespace
using namespace llvm;
namespace {
const foo *null_foo = NULL;
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, 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);
}
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);
}
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);
}
// 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 0; }
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 != NULL);
}
// 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