gprof: only process line numbers for intersection of vmas and histograms

Some programs like RTOS firmware may have a large number of symbols.
The profile information in the profile data file includes histogram
records, which capture low PC and high PC of program execution.  If all
histogram records come in the profile data file before any call-graph
records and basic-block records, we can look up only the line numbers
within low PC and high PC in histogram records, which reduces processing
time for such a firmware from ~2 minutes to ~2 seconds.

Add symbol table access function, get_symtab, get_symtab_direct and
set_symtab to delay loading the symbol table until its first use.

	* aarch64.c (aarch64_find_call): Call get_symtab to get the
	symbol table pointer
	* alpha.c (alpha_find_call): Likewise.
	* basic_blocks.c (bb_read_rec): Likewise.
	(bb_write_blocks): Likewise.
	(print_exec_counts): Likewise.
	(print_annotated_source): Likewise.
	* call_graph.c (cg_tally): Likewise.
	(cg_write_arcs): Likewise.
	* cg_arcs.c (cycle_link): Likewise.
	(propagate_flags): Likewise.
	(cg_assemble): Likewise.
	* cg_print.c (cg_print): Likewise.
	(cg_print_index): Likewise.
	(cg_print_function_ordering): Likewise.
	* corefile.c: Include "gmon_io.h".
	(core_create_syms_from): Call get_symtab_direct to get the
	symbol table pointer.
	(core_create_function_syms): Likewise.
	(core_create_line_syms): Likewise.  If all histogram records
	come in the profile data file before any call-graph records and
	basic-block records, we can look up only the line numbers within
	low PC and high PC in histogram records.
	* gmon_io.c (gmon_histograms_first): New.
	(gmon_out_read): Set gmon_histograms_first to true if all
	histogram records come first.
	(gmon_out_write): Call get_symtab to get the symbol table
	pointer.
	* hist.c (scale_and_align_entries): Likewise.
	(hist_assign_samples_1): Likewise.
	(hist_print): Likewise.
	* i386.c (i386_find_call): Likewise.
	* mips.c (mips_find_call): Likewise.
	* sparc.c (sparc_find_call): Likewise.
	* sym_ids.c (sym_id_parse): Likewise.
	* vax.c (vax_find_call): Likewise.
	* gmon_io.h (gmon_histograms_first): New.
	* gprof.c (man): Don't create profile info.
	(symtab_init): New.
	* gprof.h (symtab_init): New.
	* symtab.c (symtab): Changed to static.
	(get_symtab_direct): New.
	(get_symtab): Likewise.
	(set_symtab): Likewise.
	* symtab.h (symtab): Removed.
	(get_symtab_direct): New.
	(get_symtab): Likewise.
	(set_symtab): Likewise.

Signed-off-by: Richard Allen <rsaxvc@gmail.com>
Co-Authored-By: H.J. Lu <hjl.tools@gmail.com>

gprof/mips.c

@@ -46,6 +46,7 @@ mips_find_call (Sym *parent, bfd_vma p_lowpc, bfd_vma p_highpc)
   int offset;
   Sym *child;
   static bool inited = false;
+  Sym_Table *symtab = get_symtab ();
 
   if (!inited)
     {
@@ -75,7 +76,7 @@ mips_find_call (Sym *parent, bfd_vma p_lowpc, bfd_vma p_highpc)
 	  dest_pc = (pc & ~(bfd_vma) 0xfffffff) | offset;
 	  if (hist_check_address (dest_pc))
 	    {
-	      child = sym_lookup (&symtab, dest_pc);
+	      child = sym_lookup (symtab, dest_pc);
               if (child)
 		{
 	          DBG (CALLDEBUG,