PI74422: GENERATED STRUCT FROM DSECT UTILITY DOES NOT MATCH ORIGINAL ASM DSECT

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• After processing by the DSECT utility, a generated C struct does
  not match the memory layout of the original ASM input.
  
  The DSECT utility appears to be adding a large number of
  filler/padding bytes.
  
  
  === TEST CASE ===
  
  ZWSA     DSECT ,
  T1MAX    EQU   1345
  T1DIM    DC    A(T1MAX)
  TABLE1   DS    0D
  T1TOP    DC    (T1MAX)XL(L_T1ELEM)'00'
  T1BOT    DC    X'FFFFFFFFFFFFFFFF'
  LZWSA    EQU   *-ZWSA
  T1ELEM   DSECT ,
  T1_NOM   DS    XL8
  T1_EP    DS    F
  T1_CPT   DS    F
  T1_UTI   DS    F
  T1_TYP   DS    F
  T1_SIZ   DS    F
  T1_FEP   DS    F
  L_T1ELEM EQU   *-T1ELEM
           END
  
  
  The memory size/layout from the ASM output shows:
  ================================================================
  D-Loc    Object Code Addr1 Addr2    Stmt     Source Statement
  00000000           00000000 0000A830 1 ZWSA   DSECT ,
                      00000541          2 T1MAX EQU 1345
  00000000 00000541                    3 T1DIM  DCA(T1MAX)
  00000008                             4 TABLE1 DS 0D
  00000008 0000000000000000            5 T1TOP  DC (T1MAX)XL(L_T1E
  0000A828 FFFFFFFFFFFFFFFF            6 T1BOT  DC X'FFFFFFFFFFFFF
  
    *** SIZE OF 'ZWSA':   A828 + 8 = 0xA830
  
                                        Dsect Cross Reference
  Dsect     Length      Id       Defn
  T1ELEM   00000020  FFFFFFFE       8
  ZWSA     0000A830  FFFFFFFF       1 <<=== SIZE OF 'ZWSA' DSECT
                                               TO BE 0xA830//43056
  ================================================================
  
  The generated C struct shows:
  ================================================================
  #pragma pack(packed)
  
  struct zwsa {
    void * __ptr32 t1dim;
    unsigned char  _filler1[4];   // ***
    struct {
      unsigned char  _t1top[1345][32];
      unsigned char  _filler2[22504];   // ***
      } table1;
    unsigned char  _filler3;   // ***
    unsigned char  t1bot[8];
    };
  
  #define t1top    table1._t1top
  
  /* Values for field "t1bot" */
  #define lzwsa 0xA830
  
  struct t1elem {
    unsigned char  t1_nom[8];
    int            t1_ep;
    int            t1_cpt;
    int            t1_uti;
    int            t1_typ;
    int            t1_siz;
    int            t1_fep;
    };
  
  /* Values for field "t1_fep" */
  #define l_t1elem 0x20
  
  #pragma pack(reset)
  ================================================================
  
  The _filler# padding bytes noted by '***' are bloating the
  'zwsa'  struct to 65561 bytes, which does not match the original
  DSECT.
  

Local fix

• None.  Manually correct generated C struct.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: USERS OF XLC ON ZOS.                         *
  ****************************************************************
  * PROBLEM DESCRIPTION: WHEN THE LENGTH OF DS IS GREATER THEN   *
  *                      32767 DSECT UTILITY GENERATES INVALID   *
  *                      FILLER WHICH RESULTS WITH 'C' STRUCT    *
  *                      BEING TO LARGE AND HAVING INVALID++     *
  *                      OFFSET FOR THE MEMBERS FOLLOWING THE    *
  *                      FILLER.                                 *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  .
  

Problem conclusion

• APPLY SERVICE PROVIDED.
  

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:

  PI74434 PI74611 UI44574 PI77833

Modules/Macros

•    CCNECICS CCNECWI  CCNEDSCT CCNEDWRT CCNED210
  CCNEFILT CCNEHIFC CCNEMDEP CCNEOPTP CCNEP    CCNEPP   CCNETBY
  CCNMSGE  CCNMSGT
  

Fix information

• Fixed component name

  C/C++ FOR MVS

• Fixed component ID

  56551210A

Applicable component levels

• R790 PSY UI44574

     UP17/03/09 P F703

Fix is available

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