IJ24631: SCOPED ENUM OBJECTS MAY NOT SERIALIZE CORRECTLY

APAR status

• Closed as program error.

Error description

• With the legacy V16.1 xlC, the test case compiles and runs fine
  with -qlanglvl=scopedenum
  
  But when compiled with the new xlclang++, the resulting exe
  aborts.
  
  ===== COMPILE COMMAND:
  xlclang++ -g -std=c++14 test.cpp
  
  ===== TESTCASE:
  $ cat test.cpp
  #include <cstdio>
  #include <cassert>
  
  #if !defined(__clang__)
  #include <uchar.h>
  #endif
  
  enum SC_TOK_ROLE : char16_t
  {
    ROLE_NO_SET            = ('\1'),
    ROLE_NONE              = ('a'),
    ROLE_WORD              = ('b'),
    ROLE_KEYWORD           = ('c'),
    ROLE_TYPE              = ('d'),
    ROLE_VALUE             = ('3'),
  };
  
  static struct
  {
    char         name[30];
    SC_TOK_ROLE  role;
  }
  sypatttab[] =
  {
      { "word", ROLE_WORD },
      { "val", ROLE_VALUE },
  };
  
  int main() {
      printf("%.30s -> role(%d)\n", sypatttab[0].name,
  sypatttab[0].role);
      printf("%.30s -> role(%d)\n", sypatttab[1].name,
  sypatttab[1].role);
      assert(sypatttab[0].role == ROLE_WORD);
      assert(sypatttab[1].role == ROLE_VALUE);
      return 0;
  }
  $
  
  ===== WORKAROUND:
  when you move the main statement above the static struct AND
  remove the static-keyword, then it works fine.
  It works also if you just change the data type of the enum from
  char16_t into int16_t.
  
  
  
  ===== ACTUAL OUTPUT:
  $ xlclang++ -g -std=c++14 test.cpp
  $ ./a.out
  word -> role(4797)
  val -> role(4797)
  Assertion failed: sypatttab[0].role == ROLE_WORD, file
  test.cpp, line 32
  Abort
  $
  
  
  
  ===== EXPECTED OUTPUT:
  Same as the output with legacy xlC:
  
  
  $ xlC -g -qlanglvl=scopedenum test.cpp
  $ ./a.out
  word -> role(98)
  val -> role(51)
  $
  

Local fix

• The workaround is to move the main statement above the static
  struct AND remove the static-keyword.
  
  Another workouarnd is if you just change the data
  type of the enum from char16_t into int16_t.
  

Problem summary

• USERS AFFECTED:
  Users of C++11 scoped enum of char16_t type may be affected by
  this issue.
  
  PROBLEM DESCRIPTION:
  Serialization fails to map the underlying enum type to one of
  the
  types it knows how to serialize resulting in invalid codegen.
  

Problem conclusion

• The fix is to correctly lower the underlying type of scope
  enums.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  XL C/C++ FOR AI

• Fixed component ID

  5725C7200

Applicable component levels