struct symtabs_and_lines -> std::vector<symtab_and_line>

This replaces "struct symtabs_and_lines" with
std::vector<symtab_and_line> in most cases.  This removes a number of
cleanups.

In some cases, the sals objects do not own the sals they point at.
Instead they point at some sal that lives on the stack.  Typically
something like this:

  struct symtab_and_line sal;
  struct symtabs_and_lines sals;

  // fill in sal

  sals.nelts = 1;
  sals.sals = &sal;

  // use sals

Instead of switching those cases to std::vector too, such usages are
replaced by gdb::array_view<symtab_and_line> instead.  This avoids
introducing heap allocations.

gdb/ChangeLog:
2017-09-04  Pedro Alves  <palves@redhat.com>

	* ax-gdb.c (agent_command_1): Use range-for.
	* break-catch-throw.c (re_set_exception_catchpoint): Update.
	* breakpoint.c: Include "common/array-view.h".
	(init_breakpoint_sal, create_breakpoint_sal): Change sals
	parameter from struct symtabs_and_lines to
	array_view<symtab_and_line>.  Adjust.  Use range-for.  Update.
	(breakpoint_sals_to_pc): Change sals parameter from struct
	symtabs_and_lines to std::vector reference.
	(check_fast_tracepoint_sals): Change sals parameter from struct
	symtabs_and_lines to std::array_view.  Use range-for.
	(decode_static_tracepoint_spec): Return a std::vector instead of
	symtabs_and_lines.  Update.
	(create_breakpoint): Update.
	(break_range_command, until_break_command, clear_command): Update.
	(base_breakpoint_decode_location, bkpt_decode_location)
	(bkpt_probe_create_sals_from_location)
	(bkpt_probe_decode_location, tracepoint_decode_location)
	(tracepoint_probe_decode_location)
	(strace_marker_create_sals_from_location): Return a std::vector
	instead of symtabs_and_lines.
	(strace_marker_create_breakpoints_sal): Update.
	(strace_marker_decode_location): Return a std::vector instead of
	symtabs_and_lines.  Update.
	(update_breakpoint_locations): Change struct symtabs_and_lines
	parameters to gdb::array_view.  Adjust.
	(location_to_sals): Return a std::vector instead of
	symtabs_and_lines.  Update.
	(breakpoint_re_set_default): Use std::vector instead of struct
	symtabs_and_lines.
	(decode_location_default): Return a std::vector instead of
	symtabs_and_lines.  Update.
	* breakpoint.h: Include "common/array-view.h".
	(struct breakpoint_ops) <decode_location>: Now returns a
	std::vector instead of returning a symtabs_and_lines via output
	parameter.
	(update_breakpoint_locations): Change sals parameters to use
	gdb::array_view.
	* cli/cli-cmds.c (edit_command, list_command): Update to use
	std::vector and gdb::array_view.
	(ambiguous_line_spec): Adjust to use gdb::array_view and
	range-for.
	(compare_symtabs): Rename to ...
	(cmp_symtabs): ... this.  Change parameters to symtab_and_line
	const reference and adjust.
	(filter_sals): Rewrite using std::vector and standard algorithms.
	* elfread.c (elf_gnu_ifunc_resolver_return_stop): Simplify.
	(jump_command): Update to use std::vector.
	* linespec.c (struct linespec_state) <canonical_names>: Update
	comment.
	(add_sal_to_sals_basic): Delete.
	(add_sal_to_sals, filter_results, convert_results_to_lsals)
	(decode_line_2, create_sals_line_offset)
	(convert_address_location_to_sals, convert_linespec_to_sals)
	(convert_explicit_location_to_sals, parse_linespec)
	(event_location_to_sals, decode_line_full, decode_line_1)
	(decode_line_with_current_source)
	(decode_line_with_last_displayed, decode_objc)
	(decode_digits_list_mode, decode_digits_ordinary, minsym_found)
	(linespec_result::~linespec_result): Adjust to use std::vector
	instead of symtabs_and_lines.
	* linespec.h (linespec_sals::sals): Now a std::vector.
	(struct linespec_result): Use std::vector, bool, and in-class
	initialization.
	(decode_line_1, decode_line_with_current_source)
	(decode_line_with_last_displayed): Return std::vector.
	* macrocmd.c (info_macros_command): Use std::vector.
	* mi/mi-main.c (mi_cmd_trace_find): Use std::vector.
	* probe.c (parse_probes_in_pspace, parse_probes): Adjust to use
	std::vector.
	* probe.h (parse_probes): Return a std::vector.
	* python/python.c (gdbpy_decode_line): Use std::vector and
	gdb::array_view.
	* source.c (select_source_symtab, line_info): Use std::vector.
	* stack.c (func_command): Use std::vector.
	* symtab.h (struct symtabs_and_lines): Delete.
	* tracepoint.c (tfind_line_command, scope_info): Use std::vector.

1 files changed, 66 insertions, 100 deletions

diff --git a/gdb/cli/cli-cmds.c b/gdb/cli/cli-cmds.c
index 01ae88e..dfff87c 100644
--- a/gdb/cli/cli-cmds.c
+++ b/gdb/cli/cli-cmds.c
@@ -90,11 +90,11 @@ static void list_command (char *, int);
 
 /* Prototypes for local utility functions */
 
-static void ambiguous_line_spec (struct symtabs_and_lines *,
+static void ambiguous_line_spec (gdb::array_view<const symtab_and_line> sals,
 				 const char *format, ...)
   ATTRIBUTE_PRINTF (2, 3);
 
-static void filter_sals (struct symtabs_and_lines *);
+static void filter_sals (std::vector<symtab_and_line> &);
 
 
 /* Limit the call depth of user-defined commands */
@@ -786,7 +786,6 @@ shell_command (char *arg, int from_tty)
 static void
 edit_command (char *arg, int from_tty)
 {
-  struct symtabs_and_lines sals;
   struct symtab_and_line sal;
   struct symbol *sym;
   const char *editor;
@@ -816,25 +815,24 @@ edit_command (char *arg, int from_tty)
       arg1 = arg;
       event_location_up location = string_to_event_location (&arg1,
 							     current_language);
-      sals = decode_line_1 (location.get (), DECODE_LINE_LIST_MODE,
-			    NULL, NULL, 0);
+      std::vector<symtab_and_line> sals = decode_line_1 (location.get (),
+							 DECODE_LINE_LIST_MODE,
+							 NULL, NULL, 0);
 
-      filter_sals (&sals);
-      if (! sals.nelts)
+      filter_sals (sals);
+      if (sals.empty ())
 	{
 	  /*  C++  */
 	  return;
 	}
-      if (sals.nelts > 1)
+      if (sals.size () > 1)
 	{
-	  ambiguous_line_spec (&sals,
+	  ambiguous_line_spec (sals,
 			       _("Specified line is ambiguous:\n"));
-	  xfree (sals.sals);
 	  return;
 	}
 
-      sal = sals.sals[0];
-      xfree (sals.sals);
+      sal = sals[0];
 
       if (*arg1)
         error (_("Junk at end of line specification."));
@@ -888,7 +886,6 @@ edit_command (char *arg, int from_tty)
 static void
 list_command (char *arg, int from_tty)
 {
-  struct symtabs_and_lines sals, sals_end;
   struct symtab_and_line sal = { 0 };
   struct symtab_and_line sal_end = { 0 };
   struct symtab_and_line cursal = { 0 };
@@ -956,8 +953,8 @@ list_command (char *arg, int from_tty)
   if (!have_full_symbols () && !have_partial_symbols ())
     error (_("No symbol table is loaded.  Use the \"file\" command."));
 
-  sals.nelts = 0;
-  sals.sals = NULL;
+  std::vector<symtab_and_line> sals;
+
   arg1 = arg;
   if (*arg1 == ',')
     dummy_beg = 1;
@@ -967,15 +964,14 @@ list_command (char *arg, int from_tty)
 							     current_language);
       sals = decode_line_1 (location.get (), DECODE_LINE_LIST_MODE,
 			    NULL, NULL, 0);
-
-      filter_sals (&sals);
-      if (!sals.nelts)
+      filter_sals (sals);
+      if (sals.empty ())
 	{
 	  /*  C++  */
 	  return;
 	}
 
-      sal = sals.sals[0];
+      sal = sals[0];
     }
 
   /* Record whether the BEG arg is all digits.  */
@@ -993,12 +989,11 @@ list_command (char *arg, int from_tty)
   if (*arg1 == ',')
     {
       no_end = 0;
-      if (sals.nelts > 1)
+      if (sals.size () > 1)
 	{
-	  ambiguous_line_spec (&sals,
+	  ambiguous_line_spec (sals,
 			       _("Specified first line '%.*s' is ambiguous:\n"),
 			       (int) beg_len, beg);
-	  xfree (sals.sals);
 	  return;
 	}
       arg1++;
@@ -1014,30 +1009,25 @@ list_command (char *arg, int from_tty)
 
 	  event_location_up location
 	    = string_to_event_location (&arg1, current_language);
-	  if (dummy_beg)
-	    sals_end = decode_line_1 (location.get (),
-				      DECODE_LINE_LIST_MODE, NULL, NULL, 0);
-	  else
-	    sals_end = decode_line_1 (location.get (), DECODE_LINE_LIST_MODE,
-				      NULL, sal.symtab, sal.line);
 
-	  filter_sals (&sals_end);
-	  if (sals_end.nelts == 0)
+	  std::vector<symtab_and_line> sals_end
+	    = (dummy_beg
+	       ? decode_line_1 (location.get (), DECODE_LINE_LIST_MODE,
+				NULL, NULL, 0)
+	       : decode_line_1 (location.get (), DECODE_LINE_LIST_MODE,
+				NULL, sal.symtab, sal.line));
+
+	  filter_sals (sals_end);
+	  if (sals_end.empty ())
+	    return;
+	  if (sals_end.size () > 1)
 	    {
-	      xfree (sals.sals);
-	      return;
-	    }
-	  if (sals_end.nelts > 1)
-	    {
-	      ambiguous_line_spec (&sals_end,
+	      ambiguous_line_spec (sals_end,
 				   _("Specified last line '%s' is ambiguous:\n"),
 				   end_arg);
-	      xfree (sals_end.sals);
-	      xfree (sals.sals);
 	      return;
 	    }
-	  sal_end = sals_end.sals[0];
-	  xfree (sals_end.sals);
+	  sal_end = sals_end[0];
 	}
     }
 
@@ -1099,13 +1089,13 @@ list_command (char *arg, int from_tty)
     error (_("No default source file yet.  Do \"help list\"."));
   else if (no_end)
     {
-      for (int i = 0; i < sals.nelts; i++)
+      for (int i = 0; i < sals.size (); i++)
 	{
-	  sal = sals.sals[i];
+	  sal = sals[i];
 	  int first_line = sal.line - get_lines_to_list () / 2;
 	  if (first_line < 1)
 	    first_line = 1;
-	  if (sals.nelts > 1)
+	  if (sals.size () > 1)
 	    {
 	      printf_filtered (_("file: \"%s\", line number: %d\n"),
 			       symtab_to_filename_for_display (sal.symtab),
@@ -1123,7 +1113,6 @@ list_command (char *arg, int from_tty)
 			 ? sal.line + get_lines_to_list ()
 			 : sal_end.line + 1),
 			0);
-  xfree (sals.sals);
 }
 
 /* Subroutine of disassemble_command to simplify it.
@@ -1530,36 +1519,34 @@ alias_command (char *args, int from_tty)
 
 /* Print a list of files and line numbers which a user may choose from
    in order to list a function which was specified ambiguously (as
-   with `list classname::overloadedfuncname', for example).  The
-   vector in SALS provides the filenames and line numbers.  FORMAT is
-   a printf-style format string used to tell the user what was
+   with `list classname::overloadedfuncname', for example).  The SALS
+   array provides the filenames and line numbers.  FORMAT is a
+   printf-style format string used to tell the user what was
    ambiguous.  */
 
 static void
-ambiguous_line_spec (struct symtabs_and_lines *sals, const char *format, ...)
+ambiguous_line_spec (gdb::array_view<const symtab_and_line> sals,
+		     const char *format, ...)
 {
-  int i;
-
   va_list ap;
   va_start (ap, format);
   vprintf_filtered (format, ap);
   va_end (ap);
 
-  for (i = 0; i < sals->nelts; ++i)
+  for (const auto &sal : sals)
     printf_filtered (_("file: \"%s\", line number: %d\n"),
-		     symtab_to_filename_for_display (sals->sals[i].symtab),
-		     sals->sals[i].line);
+		     symtab_to_filename_for_display (sal.symtab),
+		     sal.line);
 }
 
-/* Sort function for filter_sals.  */
+/* Comparison function for filter_sals.  Returns a qsort-style
+   result.  */
 
 static int
-compare_symtabs (const void *a, const void *b)
+cmp_symtabs (const symtab_and_line &sala, const symtab_and_line &salb)
 {
-  const struct symtab_and_line *sala = (const struct symtab_and_line *) a;
-  const struct symtab_and_line *salb = (const struct symtab_and_line *) b;
-  const char *dira = SYMTAB_DIRNAME (sala->symtab);
-  const char *dirb = SYMTAB_DIRNAME (salb->symtab);
+  const char *dira = SYMTAB_DIRNAME (sala.symtab);
+  const char *dirb = SYMTAB_DIRNAME (salb.symtab);
   int r;
 
   if (dira == NULL)
@@ -1579,58 +1566,37 @@ compare_symtabs (const void *a, const void *b)
 	return r;
     }
 
-  r = filename_cmp (sala->symtab->filename, salb->symtab->filename);
+  r = filename_cmp (sala.symtab->filename, salb.symtab->filename);
   if (r)
     return r;
 
-  if (sala->line < salb->line)
+  if (sala.line < salb.line)
     return -1;
-  return sala->line == salb->line ? 0 : 1;
+  return sala.line == salb.line ? 0 : 1;
 }
 
 /* Remove any SALs that do not match the current program space, or
    which appear to be "file:line" duplicates.  */
 
 static void
-filter_sals (struct symtabs_and_lines *sals)
+filter_sals (std::vector<symtab_and_line> &sals)
 {
-  int i, out, prev;
-
-  out = 0;
-  for (i = 0; i < sals->nelts; ++i)
-    {
-      if (sals->sals[i].pspace == current_program_space
-	  && sals->sals[i].symtab != NULL)
-	{
-	  sals->sals[out] = sals->sals[i];
-	  ++out;
-	}
-    }
-  sals->nelts = out;
-
-  qsort (sals->sals, sals->nelts, sizeof (struct symtab_and_line),
-	 compare_symtabs);
-
-  out = 1;
-  prev = 0;
-  for (i = 1; i < sals->nelts; ++i)
-    {
-      if (compare_symtabs (&sals->sals[prev], &sals->sals[i]))
-	{
-	  /* Symtabs differ.  */
-	  sals->sals[out] = sals->sals[i];
-	  prev = out;
-	  ++out;
-	}
-    }
-
-  if (sals->nelts == 0)
-    {
-      xfree (sals->sals);
-      sals->sals = NULL;
-    }
-  else
-    sals->nelts = out;
+  /* Remove SALs that do not match.  */
+  auto from = std::remove_if (sals.begin (), sals.end (),
+			      [&] (const symtab_and_line &sal)
+    { return (sal.pspace != current_program_space || sal.symtab == NULL); });
+
+  /* Remove dups.  */
+  std::sort (sals.begin (), from,
+	     [] (const symtab_and_line &sala, const symtab_and_line &salb)
+   { return cmp_symtabs (sala, salb) < 0; });
+
+  from = std::unique (sals.begin (), from,
+		      [&] (const symtab_and_line &sala,
+			   const symtab_and_line &salb)
+    { return cmp_symtabs (sala, salb) == 0; });
+
+  sals.erase (from, sals.end ());
 }
 
 static void