Generating Code for Profiling
-----------------------------

   These macros will help you generate code for profiling.

`FUNCTION_PROFILER (FILE, LABELNO)'
     A C statement or compound statement to output to FILE some
     assembler code to call the profiling subroutine `mcount'.  Before
     calling, the assembler code must load the address of a counter
     variable into a register where `mcount' expects to find the
     address.  The name of this variable is `LP' followed by the number
     LABELNO, so you would generate the name using `LP%d' in a
     `fprintf'.

     The details of how the address should be passed to `mcount' are
     determined by your operating system environment, not by GNU CC.  To
     figure them out, compile a small program for profiling using the
     system's installed C compiler and look at the assembler code that
     results.

`PROFILE_BEFORE_PROLOGUE'
     Define this macro if the code for function profiling should come
     before the function prologue.  Normally, the profiling code comes
     after.

`FUNCTION_BLOCK_PROFILER (FILE, LABELNO)'
     A C statement or compound statement to output to FILE some
     assembler code to initialize basic-block profiling for the current
     object module.  This code should call the subroutine
     `__bb_init_func' once per object module, passing it as its sole
     argument the address of a block allocated in the object module.

     The name of the block is a local symbol made with this statement:

          ASM_GENERATE_INTERNAL_LABEL (BUFFER, "LPBX", 0);

     Of course, since you are writing the definition of
     `ASM_GENERATE_INTERNAL_LABEL' as well as that of this macro, you
     can take a short cut in the definition of this macro and use the
     name that you know will result.

     The first word of this block is a flag which will be nonzero if the
     object module has already been initialized.  So test this word
     first, and do not call `__bb_init_func' if the flag is nonzero.

`BLOCK_PROFILER (FILE, BLOCKNO)'
     A C statement or compound statement to increment the count
     associated with the basic block number BLOCKNO.  Basic blocks are
     numbered separately from zero within each compilation.  The count
     associated with block number BLOCKNO is at index BLOCKNO in a
     vector of words; the name of this array is a local symbol made
     with this statement:

          ASM_GENERATE_INTERNAL_LABEL (BUFFER, "LPBX", 2);

     Of course, since you are writing the definition of
     `ASM_GENERATE_INTERNAL_LABEL' as well as that of this macro, you
     can take a short cut in the definition of this macro and use the
     name that you know will result.

`BLOCK_PROFILER_CODE'
     A C function or functions which are needed in the library to
     support block profiling.