Files
clang-p2996/clang/test/CodeGenCXX/microsoft-uuidof-mangling.cpp
Richard Smith bab6df86ae Rework how UuidAttr, CXXUuidofExpr, and GUID template arguments and constants are represented.
Summary:
Previously, we treated CXXUuidofExpr as quite a special case: it was the
only kind of expression that could be a canonical template argument, it
could be a constant lvalue base object, and so on. In addition, we
represented the UUID value as a string, whose source form we did not
preserve faithfully, and that we partially parsed in multiple different
places.

With this patch, we create an MSGuidDecl object to represent the
implicit object of type 'struct _GUID' created by a UuidAttr. Each
UuidAttr holds a pointer to its 'struct _GUID' and its original
(as-written) UUID string. A non-value-dependent CXXUuidofExpr behaves
like a DeclRefExpr denoting that MSGuidDecl object. We cache an APValue
representation of the GUID on the MSGuidDecl and use it from constant
evaluation where needed.

This allows removing a lot of the special-case logic to handle these
expressions. Unfortunately, many parts of Clang assume there are only
a couple of interesting kinds of ValueDecl, so the total amount of
special-case logic is not really reduced very much.

This fixes a few bugs and issues:
 * PR38490: we now support reading from GUID objects returned from
   __uuidof during constant evaluation.
 * Our Itanium mangling for a non-instantiation-dependent template
   argument involving __uuidof no longer depends on which CXXUuidofExpr
   template argument we happened to see first.
 * We now predeclare ::_GUID, and permit use of __uuidof without
   any header inclusion, better matching MSVC's behavior. We do not
   predefine ::__s_GUID, though; that seems like a step too far.
 * Our IR representation for GUID constants now uses the correct IR type
   wherever possible. We will still fall back to using the
      {i32, i16, i16, [8 x i8]}
   layout if a definition of struct _GUID is not available. This is not
   ideal: in principle the two layouts could have different padding.

Reviewers: rnk, jdoerfert

Subscribers: arphaman, cfe-commits, aeubanks

Tags: #clang

Differential Revision: https://reviews.llvm.org/D78171
2020-04-15 12:20:42 -07:00

58 lines
2.0 KiB
C++

// RUN: %clang_cc1 -emit-llvm %s -o - -triple x86_64-unknown-unknown -fms-extensions | FileCheck %s
// rdar://17784718
typedef struct _GUID
{
unsigned int Data1;
unsigned short Data2;
unsigned short Data3;
unsigned char Data4[ 8 ];
} GUID;
template < typename T, const GUID & T_iid = __uuidof(T)>
class UUIDTest
{
public:
UUIDTest() { }
};
struct __declspec(uuid("EAFA1952-66F8-438B-8FBA-AF1BBAE42191")) TestStruct
{
int foo;
};
struct __declspec(uuid("EAFA1952-66F8-438B-8FBA-AF1BBAE42191")) OtherStruct {};
template <class T> void test_uuidofType(void *arg[sizeof(__uuidof(T))] = 0) {}
template <class T> void test_uuidofExpr(void *arg[sizeof(__uuidof(typename T::member))] = 0) {}
struct HasMember { typedef TestStruct member; };
template<const GUID&> struct UUIDTestTwo { UUIDTestTwo(); };
int main(int argc, const char * argv[])
{
UUIDTest<TestStruct> uuidof_test;
// Note that these variables have the same type, so the mangling of that
// type had better not mention TestStruct or OtherStruct!
UUIDTestTwo<__uuidof(TestStruct)> uuidof_test2;
UUIDTestTwo<__uuidof(OtherStruct)> uuidof_test3;
test_uuidofType<TestStruct>();
test_uuidofExpr<HasMember>();
return 0;
}
// CHECK: define i32 @main
// CHECK: call void @_ZN8UUIDTestI10TestStructL_Z42_GUID_eafa1952_66f8_438b_8fba_af1bbae42191EEC1Ev
// CHECK: call void @_ZN11UUIDTestTwoIL_Z42_GUID_eafa1952_66f8_438b_8fba_af1bbae42191EEC1Ev
// CHECK: call void @_ZN11UUIDTestTwoIL_Z42_GUID_eafa1952_66f8_438b_8fba_af1bbae42191EEC1Ev
// CHECK: call void @_Z15test_uuidofTypeI10TestStructEvPPv(i8** null)
// CHECK: call void @_Z15test_uuidofExprI9HasMemberEvPPv(i8** null)
// CHECK: define linkonce_odr void @_ZN8UUIDTestI10TestStructL_Z42_GUID_eafa1952_66f8_438b_8fba_af1bbae42191EEC1Ev
// CHECK: define linkonce_odr void @_Z15test_uuidofTypeI10TestStructEvPPv
// CHECK: define linkonce_odr void @_Z15test_uuidofExprI9HasMemberEvPPv
// CHECK: define linkonce_odr void @_ZN8UUIDTestI10TestStructL_Z42_GUID_eafa1952_66f8_438b_8fba_af1bbae42191EEC2Ev