A fix is available
APAR status
Closed as new function.
Error description
Part of cobol's optimization strategies is inlining of performed sections/paragraphs. This strategy fails to provide any benefit at execution time for certain programming styles, where the mainline code contains many performs to error checking routines, e.q. many SQL followed by Perform to common check routine: EXEC SQL ... END-EXEC If SQLCODE Not = 0 Perform 999-Check-SQLCODE End-If Another often used style is to Perform into a Section, which logs some error condition and eventually calls a common abend sub program to terminate the enclave. When such Performs are heavily coded in a program, the compilation with optimize(1|2) yields to a big increase of the code size (and the compilation time) while decreasing the efficiency of the code because the inlined code is very seldom executed at execution time and only pollutes the instruction cache. Adding Cobol Compiler Directive Statements to guide Cobol's optimization and increase execution efficiency of compiled cobol programs.
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: Users of Enterprise COBOL who want to * * exercise more control over the compiler * * optimization process, specifically the * * inlining of procedures (paragraphs or * * sections) referenced by PERFORM * * statements. * * * **************************************************************** * PROBLEM DESCRIPTION: Part of COBOL's optimization strategy * * is the inlining of performed sections * * and paragraphs (procedures). This * * strategy fails to provide any benefit * * at execution time for certain * * programming styles, where the mainline * * code contains many performs to error * * checking routines, i.e. many SQL * * statements followed by a PERFORM of a * * common error checking routine: * * * * * * EXEC SQL ... END-EXEC * * * * If SQLCODE Not = 0 * * PERFORM 999-Check-SQLCODE * * End-If * * * * Another often used style is to PERFORM * * into a section which logs some error * * condition and eventually calls a common * * ABEND sub program to terminate the * * enclave. * * * * When such PERFORMs are heavily coded in * * a program, compilation with compiler * * option OPT(1) or OPT(2) can lead to * * a big increase in the resulting program * * size (and increase in compilation time) * * while decreasing the efficiency of the * * program because the inlined code is * * very seldom executed at run time but * * has the negative side effect of * * invalidating the instruction cache. * * * **************************************************************** * RECOMMENDATION: Install the provided PTFs and use the * * newly provided INLINE options and * * >>INLINE directives, as appropriate. * * * **************************************************************** New inlining compiler options and inlining directives are provided to guide COBOL's inlining optimization process. behavior when the COBOL program was migrated from COBOL V4 to For consistency with existing Enterprise COBOL options, a new compiler option INLINE|NOINLINE has been added. If the INLINE option is in effect at compile time, it's scope will be the entire COBOL program, unless it is overridden by the inlining directives. It only allows the optimizer to choose whether or not to inline procedures (performed paragraphs or sections). If the NOINLINE option is in effect at compile time, no inlining will occur and all >>INLINE directives will be ignored. The syntax for the inlining option is as follows: .-INLINE---. >>-+----------+-------------------------------------------->< '-NOINLINE-' New compiler directives have also been added to the Enterprise COBOL compiler to control inlining. They have been implemented as a begin/end style of bracketing, similar to the existing CALLINTERFACE directive. The syntax for the inlining directives is as follows: >--->>INLINE----+--ON---+--------------------------------> | | '--OFF--' Note: The INLINE directive can appear multiple times in the program, but it can only be specified in the PROCEDURE DIVISION.
Problem conclusion
Temporary fix
Comments
The new inlining option and inlining directives will provide the compiler user with more control over the optimizer during the inlining phase of optimization. It is only effective when either OPTIMIZE(1) or OPTIMIZE(2) are specified as compiler options. 1. Programming Guide -> Debugging- > Getting listings -> Reading LIST output-> Signature information bytes Table 54. Signature information bytes (continued) -------------------------------------------------------------- |Offset in decimal |Signature byte |Bit |Item | -------------------------------------------------------------- |30 | 23 | 0 | COPY | -------------------------------------------------------------- | | | 1 | BASIS | -------------------------------------------------------------- | | | 2 | DBCS name in| | | | | program | -------------------------------------------------------------- | | | 3 | Shift-out | | | | | and Shift-in| | | | | in program | -------------------------------------------------------------- | | | 4 | SUPPRESS | | | | | NOSUPRESS | -------------------------------------------------------------- | | | 5 | SSRANGE ZLEN| -------------------------------------------------------------- | | | 6 | SSRANGE ABD | -------------------------------------------------------------- | | | 7 | INLINE | | | | | NOINLINE | -------------------------------------------------------------- 2. Language Reference -> Compiler Directives -> INLINE Use the INLINE directive to instruct the compiler to inline procedures referenced by PERFORM statements in the source program. If the NOINLINE option is in effect at compile time, then INLINE directives are ignored. >--->>INLINE----+--ON---+---------------------------------> | | '--OFF--' ON If OPTIMIZE(1) or OPTIMIZE(2) is in effect, inlining of procedures referenced by PERFORM statements is allowed. The decision to inline procedures in a specific PERFORM block is made by the compiler. OFF Regardless of the optimization level setting in effect, no inlining of PERFORM procedures will occur. Syntax and general rules You must specify >>INLINE ON or >>INLINE OFF on a line by itself, in either Area A or Area B. You cannot specify >>INLINE ON or >>INLINE OFF in the following cases: 1. Within a COPY or REPLACE statement 2. Between the lines of a continued character string 3. In the middle of a COBOL statement The >>INLINE ON or >>INLINE OFF specification is limited to the current compilation unit. Note: The INLINE directive can appear multiple times in the program and will be implemented as a begin/end type of bracketing. Inlining eligibility of procedures for PERFORM statements: A procedure is "in the scope of" an INLINE directive if the INLINE directive appears in the program before the definition of the procedure name and there are no other intervening INLINE directives between the definition of the procedure name and the INLINE directive in question.1 A procedure is eligible for inlining for statements of the form "PERFORM procedure-name-1 THROUGH procedure-name-2 " if and only if: the procedure is in the scope of an INLINE ON directive; or The INLINE compiler option is in effect and the procedure is not in the scope of an INLINE OFF directive. Notes: 1. For sections that are contain paragraphs, it is possible for the section to be under the scope of one INLINE directive while one or more of its paragraphs are under the scope of a different INLINE directive. An example of the effect of the INLINING directive on a SECTION that is comprised of one or more paragraphs: >>INLINE ON MY-SUBROUTINE SECTION. MY-PARAGRAPH-ONE. : >>INLINE OFF MY-PARAGRAPH-TWO. : MY-PARAGRAPH-THREE. : EXIT. 1. Procedure MY-SUBROUTINE will be eligible for inlining in the statement "PERFORM MY-SUBROUTINE". 2. Procedure MY-PARAGRAPH-ONE will be eligible for inlining in the statement "PERFORM MY-PARAGRAPH-ONE". 3. Procedure MY-PARAGRAPH-TWO will not be eligible for inlining in the statement "PERFORM MY-PARAGRAPH-TWO". 4. Procedure MY-PARAGRAPH-THREE will not be eligible for inlining in the statement "PER-FORM MY-PARAGRAPH-THREE". 5. Procedures MY-PARAGRAPH-ONE through MY-PARAGRAPH-THREE will be eligible for inlin-ing in the statement "PERFORM MY-PARAGRAPH-ONE THRU MY-PARAGRAPH-THREE" since MY-PARAGRAPH-ONE is eligible for inlining in a PERFORM statement. 3. Programming Guide -> Compiling and debugging your program -> Compiler Options -> INLINE Use the NOINLINE option to prevent the compiler from inlining procedures (paragraphs or sections) referenced by PERFORM statements in the source program. INLINE option syntax .-INLINE---. >>-+----------+--------------------------------------------->< '-NOINLINE-' Default is: INLINE Abbreviations are: INL|NOINL INLINE If OPTIMIZE(1) or OPTIMIZE(2) is in effect, inlining of procedures referenced by PERFORM statements is allowed. The decision to inline procedures in a specific PERFORM block is made by the compiler. This decision can be overridden by use of the >>INLINE OFF compiler directive. NOINLINE Regardless of the optimization level setting in effect, no inlining of PERFORM procedures will occur. This decision cannot be overridden by use of the >>INLINE ON directive. 4. Enterprise COBOL Customization Guide -> Enterprise COBOL compiler Options Use the INLINE=YES option to allow the compiler to inline procedures (paragraphs or sections) referenced by PERFORM statements in the source program. INLINE option syntax '-NO--' >>--INLINE=--+---+--+-YES-+------------------------------>< '-*-' Default INLINE=YES Yes When OPTIMIZE(1) or OPTIMIZE(2) are in effect, the compiler may choose to inline procedures referenced by PERFORM statements in the source program. No The compiler is prevented from inlining procedures referenced by PERFORM statements in the source program.
APAR Information
APAR number
PI77981
Reported component name
ENT COBOL FOR Z
Reported component ID
5655EC600
Reported release
610
Status
CLOSED UR1
PE
NoPE
HIPER
NoHIPER
Special Attention
YesSpecatt / New Function / Xsystem
Submitted date
2017-03-10
Closed date
2017-04-25
Last modified date
2017-05-01
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Modules/Macros
IGYCRCTL
| SC27871200 |
Fix information
Fixed component name
ENT COBOL FOR Z
Fixed component ID
5655EC600
Applicable component levels
R610 PSY UI46711
UP17/04/29 P F704
Fix is available
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Document Information
Modified date:
05 September 2024