section_table_xfer_memory: Replace section name with callback predicate

This patch is motivated by the need to be able to select sections
that section_table_xfer_memory_partial should consider for memory
transfers.  I'll use this facility in the next patch in this series.

section_table_xfer_memory_partial() can currently be passed a section
name which may be used to make name-based selections.  This is similar
to what I want to do, except that I want to be able to consider
section flags instead of the name.

I'm replacing the section name parameter with a predicate that,
when passed a pointer to a target_section struct, will return
true if that section should be further considered, or false which
indicates that it shouldn't.

I've converted the one existing use where a non-NULL section
name is passed to section_table_xfer_memory_partial().   Instead
of passing the section name, it now looks like this:

	  auto match_cb = [=] (const struct target_section *s)
	    {
	      return (strcmp (section_name, s->the_bfd_section->name) == 0);
	    };

	  return section_table_xfer_memory_partial (readbuf, writebuf,
						    memaddr, len, xfered_len,
						    table->sections,
						    table->sections_end,
						    match_cb);

The other callers all passed NULL; they've been simplified somewhat
in that they no longer need to pass NULL.

gdb/ChangeLog:

	* exec.h (section_table_xfer_memory): Revise declaration,
	replacing section name parameter with an optional callback
	predicate.
	* exec.c (section_table_xfer_memory): Likewise.
	* bfd-target.c, exec.c, target.c, corelow.c: Adjust all callers
	of section_table_xfer_memory.

1 files changed, 4 insertions, 4 deletions

diff --git a/gdb/exec.c b/gdb/exec.c
index 2ff5846..e50f388 100644
--- a/gdb/exec.c
+++ b/gdb/exec.c
@@ -956,7 +956,8 @@ section_table_xfer_memory_partial (gdb_byte *readbuf, const gdb_byte *writebuf,
 				   ULONGEST *xfered_len,
 				   struct target_section *sections,
 				   struct target_section *sections_end,
-				   const char *section_name)
+				   gdb::function_view<bool
+				     (const struct target_section *)> match_cb)
 {
   int res;
   struct target_section *p;
@@ -970,7 +971,7 @@ section_table_xfer_memory_partial (gdb_byte *readbuf, const gdb_byte *writebuf,
       struct bfd_section *asect = p->the_bfd_section;
       bfd *abfd = asect->owner;
 
-      if (section_name && strcmp (section_name, asect->name) != 0)
+      if (match_cb != nullptr && !match_cb (p))
 	continue;		/* not the section we need.  */
       if (memaddr >= p->addr)
         {
@@ -1043,8 +1044,7 @@ exec_target::xfer_partial (enum target_object object,
     return section_table_xfer_memory_partial (readbuf, writebuf,
 					      offset, len, xfered_len,
 					      table->sections,
-					      table->sections_end,
-					      NULL);
+					      table->sections_end);
   else
     return TARGET_XFER_E_IO;
 }