[LLVMbugs] [Bug 14983] New: [Windows] Wrong class layout in the presence of __int64 and vftable

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=14983

             Bug #: 14983
           Summary: [Windows] Wrong class layout in the presence of
                    __int64 and vftable
           Product: clang
           Version: trunk
          Platform: PC
        OS/Version: Windows NT
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: C++
        AssignedTo: unassignedclangbugs at nondot.org
        ReportedBy: timurrrr at google.com
                CC: dgregor at apple.com, llvmbugs at cs.uiuc.edu
    Classification: Unclassified


---test.cpp---
struct Base {
  int x;
};

struct Child : Base {
  __int64 y;
  virtual void foo() {}
};

extern "C" int printf(const char *fmt, ...);

int main() {
  Child s;
  printf("x offset = %lu\n", (unsigned long)&s.x - (unsigned long)&s);
  printf("y offset = %lu\n", (unsigned long)&s.y - (unsigned long)&s);
}
--------------

$ clang -cc1 -cxx-abi microsoft -triple i686-pc-win32 -fms-compatibility
-emit-llvm-only -fdump-record-layouts -o - test.cpp
...
*** Dumping AST Record Layout
   0 | struct Child
   4 |   struct Base (base)
   4 |     int x
   0 |   (Child vftable pointer)
   8 |   long long y
     | [sizeof=16, dsize=16, align=8
     |  nvsize=16, nvalign=8]
...

$ clang -Xclang -cxx-abi -Xclang microsoft -fno-rtti test.cpp && ./a.out
# Please note I have vtable generation code locally
x offset = 4
y offset = 8

Should be:
x offset = 8
y offset = 16

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