Studying note of GCC-3.4.6 source (24 cont)

-foptimize-sibling-calls	Refer to flag_optimize_sibling_calls	CL_COMMON
-foptional-diags	Enable optional diagnostics	CL_CXX | CL_ObjCXX
-fpack-struct	Refer to flag_pack_struct	CL_COMMON
-fpcc-struct-return	Refer to flag_pcc_struct_return	CL_COMMON
-fpch-deps	When using precompiled headers, this flag will cause the dependency-output flags to also list the files from the precompiled header’s dependencies. If not specified only the precompiled header would be listed and not the files that were used to create it because those files are not consulted when a precompiled header is used.	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX
-fpeel-loops	Refer to flag_peel_loops	CL_COMMON
-fpeephole	Refer to flag_no_peephole	CL_COMMON
-fpeephole2	Refer to flag_peephole2	CL_COMMON
-fpermissive	Refer to flag_permissive	CL_CXX | CL_ObjCXX
-fpic	Refer to flag_pic	CL_COMMON
-fpie	Refer to flag_pie	CL_COMMON
-fprefetch-loop-arrays	Refer to flag_prefetch_loop_arrays	CL_COMMON
-fpreprocessed	Refer to flag_preprocess_only	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX
-fprofile	Enable basic program profiling code	CL_COMMON
-fprofile-arcs	Insert arc-based program profiling code	CL_COMMON
-fprofile-generate	Enable common options for generating profile info for profile feedback directed optimizations	CL_COMMON
-fprofile-use	Enable common options for performing profile feedback directed optimizations	CL_COMMON
-fprofile-values	Insert code to profile values of expressions	CL_COMMON
-frandom-seed	Refer to flag_random_seed	CL_COMMON
-frandom-seed=<string>		CL_COMMON | CL_JOINED | CL_REJECT_NEGATIVE
-freduce-all-givs	Refer to flag_reduce_all_givs	CL_COMMON
-freg-struct-return	Return small aggregates in registers	CL_COMMON
-fregmove	Enables a register move optimization	CL_COMMON
-frename-registers	Perform a register renaming optimization pass	CL_COMMON
-freorder-blocks	Refer to flag_reorder_blocks	CL_COMMON
-freorder-functions	Refer to flag_reorder_functions	CL_COMMON
-frepo	Enable automatic template instantiation	CL_CXX | CL_ObjCXX
-frerun-cse-after-loop	Add a common subexpression elimination pass after loop optimizations	CL_COMMON
-frerun-loop-opt	Run the loop optimizer twice	CL_COMMON
-frounding-math	Disable optimizations that assume default FP rounding behavior	CL_COMMON
-frtti	Generate run time type descriptor information	CL_CXX | CL_ObjCXX
-fsched-interblock	Enable scheduling across basic blocks	CL_COMMON
-fsched-spec	Refer to flag_schedule_speculative	CL_COMMON
-fsched-spec-load	Refer to flag_schedule_speculative_load	CL_COMMON
-fsched-spec-load-dangerous	Refer to flag_schedule_speculative_load_dangerous	CL_COMMON
-fsched-stalled-insns	Refer to flag_sched_stalled_insns	CL_COMMON
-fsched-stalled-insns=<number>		CL_COMMON | CL_JOINED | CL_REJECT_NEGATIVE | CL_UINTEGER
-fsched-stalled-insns-dep	Refer to flag_sched_stalled_insns_dep	CL_COMMON
-fsched-stalled-insns-dep=<number>		CL_COMMON | CL_JOINED | CL_REJECT_NEGATIVE | CL_UINTEGER
-fsched-verbose=<number>	Set the verbosity level of the scheduler	CL_COMMON | CL_JOINED | CL_REJECT_NEGATIVE
-fsched2-use-superblocks	Refer to flag_sched2_use_superblocks	CL_COMMON
-fsched2-use-traces	Refer to flag_sched2_use_traces	CL_COMMON
-fschedule-insns	Refer to flag_schedule_insns	CL_COMMON
-fschedule-insns2	Refer to flag_schedule_insns_after_reload	CL_COMMON
-fshared-data	Refer to flag_shared_data	CL_COMMON
-fshort-double	Refer to flag_short_double	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX
-fshort-enums	Refer to flag_short_enums	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX
-fshort-wchar	Refer to flag_short_wchar	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX
-fshow-column	!!! This switch lacks documentation	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX
-fsignaling-nans	Refer to flag_signaling_nans	CL_COMMON
-fsigned-bitfields	When "signed" or "unsigned" is not given make the bitfield signed	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX
-fsigned-char	Make "char" signed by default	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX
-fsingle-precision-constant	Convert floating point constants to single precision constants	CL_COMMON
-fsquangle	Depricated	CL_CXX | CL_ObjCXX
-fstack-check	Insert stack checking code into the program	CL_COMMON
-fstack-limit	Refer to stack_limit_rtx	CL_COMMON
-fstack-limit-register=<register>		CL_COMMON | CL_JOINED | CL_REJECT_NEGATIVE
-fstack-limit-symbol=<name>
-fstats	Display statistics accumulated during compilation	CL_CXX | CL_ObjCXX
-fstrength-reduce	Perform strength reduction optimizations	CL_COMMON
-fstrict-aliasing	Assume strict aliasing rules apply	CL_COMMON
-fstrict-prototype	Depricated	CL_CXX | CL_ObjCXX
-fsyntax-only	Check for syntax errors, then stop	CL_COMMON
-ftabstop=<number>	Distance between tab stops for column reporting	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX | CL_JOINED | CL_REJECT_NEGATIVE | CL_UINTEGER
-ftemplate-depth-<number>	Specify maximum template instantiation depth	CL_CXX | CL_ObjCXX | CL_JOINED | CL_REJECT_NEGATIVE | CL_UINTEGER
-ftest-coverage	Create data files needed by "gcov"	CL_COMMON
-fthis-is-variable	Depricated	CL_CXX | CL_ObjCXX
-fthread-jumps	Refer to flag_thread_jumps	CL_COMMON
-ftime-report	Report the time taken by each compiler pass	CL_COMMON
-ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec]	Set the default thread-local storage code generation model	CL_COMMON | CL_JOINED | CL_REJECT_NEGATIVE
-ftracer	Refer to flag_tracer	CL_COMMON
-ftrapping-math	Assume floating-point operations can trap	CL_COMMON
-ftrapv	Trap for signed overflow in addition, subtraction and multiplication	CL_COMMON
-funit-at-a-time	Compile whole compilation unit at a time	CL_COMMON
-funroll-all-loops	Perform loop unrolling for all loops	CL_COMMON
-funroll-loops	Perform loop unrolling when iteration count is known	CL_COMMON
-funsafe-math-optimizations	Allow math optimizations that may violate IEEE or ISO standards	CL_COMMON
-funsigned-bitfields	When "signed" or "unsigned" is not given make the bitfield unsigned	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX
-funsigned-char	Make "char" unsigned by default	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX
-funswitch-loops	Refer to flag_unswitch_loops	CL_COMMON
-funwind-tables	Refer to flag_unwind_tables	CL_COMMON
-fuse-cxa-atexit	Use __cxa_atexit to register destructors	CL_CXX | CL_ObjCXX
-fverbose-asm	Add extra commentary to assembler output	CL_COMMON
-fvpt	Use expression value profiles in optimizations	CL_COMMON
-fvtable-gc	Discard unused virtual functions	CL_CXX | CL_ObjCXX
-fvtable-thunks	Implement vtables using thunks	CL_CXX | CL_ObjCXX
-fweak	Refer to flag_weak	CL_CXX | CL_ObjCXX
-fweb	Refer to flag_web	CL_COMMON
-fwide-exec-charset=<cset>	Convert all wide strings and character constants to character set <cset>	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX | CL_JOINED | CL_REJECT_NEGATIVE
-fworking-directory	Generate a #line directive pointing at the current working directory	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX
-fwrapv	Assume signed arithmetic overflow wraps around	CL_COMMON
-fwritable-strings	Store strings in writable data section	CL_COMMON
-fxref	Emit cross referencing information	CL_CXX | CL_ObjCXX
-fzero-initialized-in-bss	Put zero initialized data in the bss section	CL_COMMON
-g	Generate debug information in default format	CL_COMMON | CL_JOINED | CL_MISSING_OK
-gcoff	Generate debug information in COFF format	CL_COMMON | CL_JOINED | CL_MISSING_OK
-gdwarf-2	Generate debug information in DWARF v2 format	CL_COMMON | CL_JOINED | CL_MISSING_OK
-ggdb	Generate debug information in default extended format	CL_COMMON | CL_JOINED | CL_MISSING_OK
-gstabs	Generate debug information in STABS format	CL_COMMON | CL_JOINED | CL_MISSING_OK
-gstabs+	Generate debug information in extended STABS format	CL_COMMON | CL_JOINED | CL_MISSING_OK
-gvms	Generate debug information in VMS format	CL_COMMON | CL_JOINED | CL_MISSING_OK
-gxcoff	Generate debug information in XCOFF format	CL_COMMON | CL_JOINED | CL_MISSING_OK
-gxcoff+	Generate debug information in extended XCOFF format	CL_COMMON | CL_JOINED | CL_MISSING_OK
-idirafter<dir>	Add <dir> to the end of the system include path	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX | CL_JOINED | CL_SEPARATE
-imacros<file>	Accept definition of macros in <file>, but throw away any output produced by scanning <file>	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX | CL_JOINED | CL_SEPARATE
-include<file>	Include the contents of <file> before other files	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX | CL_JOINED | CL_SEPARATE
-iprefix<path>	Refer to iprefix	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX | CL_JOINED | CL_SEPARATE
-isysroot<dir>	Set <dir> to be the system root directory	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX | CL_JOINED | CL_SEPARATE
-isystem<dir>	Add <dir> to the start of the system include path	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX | CL_JOINED | CL_SEPARATE
-iwithprefix<dir>	Refer to add_prefixed_path	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX | CL_JOINED | CL_SEPARATE
-iwithprefixbefore<dir>
-lang-asm	!!! This switch lacks documentation	CL_C | CL_UNDOCUMENTED
-lang-objc	Compile code of objC	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX | CL_UNDOCUMENTED
-m	Prefix for options related to target	CL_COMMON | CL_JOINED
-nostdinc	Do not search standard system include directories (those specified with -isystem will still be used)	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX
-nostdinc++	Do not search standard system include directories for C++	CL_CXX | CL_ObjCXX
-o <file>	Place output into <file>	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX | CL_COMMON | CL_JOINED | CL_SEPARATE
-p	Enable function profiling	CL_COMMON
-pedantic	Issue warnings needed for strict compliance to the standard	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX | CL_COMMON
-pedantic-errors	Like -pedantic but issue them as errors	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX | CL_COMMON
-quiet	Do not display functions compiled or elapsed time	CL_COMMON
-remap	Enable special code to work around file systems which only permit very shortfile names, such as MS-DOS.	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX
-std=c++98	Conform to the ISO 1998 C++ standard	CL_CXX | CL_ObjCXX
-std=c89	Conform to the ISO 1990 C standard	CL_C | CL_ObjC
-std=c99	Conform to the ISO 1999 C standard	CL_C | CL_ObjC
-std=c9x	Deprecated in favor of -std=c99	CL_C | CL_ObjC
-std=gnu++98	Conform to the ISO 1998 C++ standard with GNU extensions	CL_CXX | CL_ObjCXX
-std=gnu89	Conform to the ISO 1990 C standard with GNU extensions	CL_C | CL_ObjC
-std=gnu99	Conform to the ISO 1999 C standard with GNU extensions	CL_C | CL_ObjC
-std=gnu9x	Deprecated in favor of -std=gnu99	CL_C | CL_ObjC
-std=iso9899:1990	Conform to the ISO 1990 C standard	CL_C | CL_ObjC
-std=iso9899:199409	Conform to the ISO 1990 C standard as amended in 1994	CL_C | CL_ObjC
-std=iso9899:1999	Conform to the ISO 1999 C standard	CL_C | CL_ObjC
-std=iso9899:199x	Deprecated in favor of -std=iso9899:1999	CL_C | CL_ObjC
-traditional-cpp	Enable traditional preprocessing	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX
-trigraphs	Support ISO C trigraphs	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX
-undef	Do not predefine system-specific and GCC-specific macros	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX
-v	Enable verbose output	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX
-version	Display the compiler's version	CL_COMMON
-w	Suppress warnings	CL_C | CL_CXX | CL_ObjC | CL_ObjCXX | CL_COMMON

Table 11: C++ language specified options

In above table, options are assigned variable flags set, in which 2 groups are identified. One is to indicate the specified langauge the options applied.

 

3     #define CL_C       (1 << 0)                                                                   in options.h

4     #define CL_CXX     (1 << 1)

5     #define CL_ObjC    (1 << 2)

6     #define CL_ObjCXX  (1 << 3)

 

The other tells other characteristics of the options, in which CL_COMMON should belong to first group.

 

40    #define CL_JOINED            (1 << 24) /* If takes joined argument.  */                 in opts.h

41    #define CL_SEPARATE (1 << 25) /* If takes a separate argument.  */

42    #define CL_REJECT_NEGATIVE       (1 << 26) /* Reject no- form.  */

43    #define CL_MISSING_OK          (1 << 27) /* Missing argument OK (joined).  */

44    #define CL_UINTEGER              (1 << 28) /* Argument is an integer >=0.  */

45    #define CL_COMMON         (1 << 29) /* Language-independent.  */

46    #define CL_UNDOCUMENTED  (1 << 30) /* Do not output with --help.  */

 

When arriving here, it means the option really within cl_options, it now needs to check its validity. Below testing at line 397 has been executed by find_opt, however find_opt still accepts the unmatching options for the language; so here find them out again, gives out warning and does abandonment.

 

handle_option (continue)

 

364    /* We've recognized this switch.  */

365    result = 1;

366 

367    /* Sort out any argument the switch takes.  */

368    if (option->flags & CL_JOINED)

369    {

370      /* Have arg point to the original switch. This is because

371        some code, such as disable_builtin_function, expects its

372        argument to be persistent until the program exits.  */

373      arg = argv[0] + cl_options[opt_index].opt_len + 1;

374      if (!value)

375        arg += strlen ("no-");

376 

377      if (*arg == '/0' && !(option->flags & CL_MISSING_OK))

378      {

379        if (option->flags & CL_SEPARATE)

380        {

381          arg = argv[1];

382          result = 2;

383        }

384        else

385          /* Missing argument.  */

386          arg = NULL;

387      }

388    }

389    else if (option->flags & CL_SEPARATE)

390    {

391      arg = argv[1];

392      result = 2;

393    }

394 

395    /* Now we've swallowed any potential argument, complain if this

396      is a switch for a different front end.  */

397    if (!(option->flags & (lang_mask | CL_COMMON)))

398    {

399     complain_wrong_lang (argv[0], option, lang_mask);

400      goto done;

401    }

402 

403    if (arg == NULL && (option->flags & (CL_JOINED | CL_SEPARATE)))

404    {

405      if (!(*lang_hooks.missing_argument) (opt, opt_index))

406        error ("missing argument to /"%s/"", opt);

407      goto done;

408    }

409 

410    /* If the switch takes an integer, convert it.  */

411    if (arg && (option->flags & CL_UINTEGER))

412    {

413      value = integral_argument (arg);

414      if (value == -1)

415      {

416        error ("argument to /"%s/" should be a non-negative integer",

417             option->opt_text);

418        goto done;

419      }

420    }

 

For option of CL_JOINED, it looks like -A=value or -Avalue, and for option of CL_SEPARATE, it looks like -A= value or -A value. So above code snippet fetches the parameter of the option.

 

handle_option (continue)

 

422    if (option->flags & lang_mask)

423      if ((*lang_hooks.handle_option) (opt_index, arg, value) == 0)

424        result = 0;

425 

426    if (result && (option->flags & CL_COMMON))

427      if (c_common_handle_option (opt_index, arg, value) == 0)

428        result = 0;

429 

430  done:

431    if (dup)

432      free (dup);

433    return result;

434  }

 

Condition at line 422 selects out the options specially for the language, and passes them to the hook of the front-end.