gdb: spread a little 'const' through the target_section_table code

The code to access the target section table can be made more const, so
lets do that.  There should be no user visible changes after this
commit.

gdb/ChangeLog:

	* gdb/bfd-target.c (class target_bfd) <get_section_table>: Make
	return type const.
	* gdb/exec.c (struct exec_target) <get_section_table>: Likewise.
	(section_table_read_available_memory): Make local const.
	(exec_target::xfer_partial): Make local const.
	(print_section_info): Make parameter const.
	* gdb/exec.h (print_section_info): Likewise.
	* gdb/ppc64-tdep.c (ppc64_convert_from_func_ptr_addr): Make local
	const.
	* gdb/record-btrace.c (record_btrace_target::xfer_partial):
	Likewise.
	* gdb/remote.c (remote_target::remote_xfer_live_readonly_partial):
	Likewise.
	* gdb/s390-tdep.c (s390_load): Likewise.
	* gdb/solib-dsbt.c (scan_dyntag): Likewise.
	* gdb/solib-svr4.c (scan_dyntag): Likewise.
	* gdb/target-debug.h (target_debug_print_target_section_table_p):
	Rename to...
	(target_debug_print_const_target_section_table_p): ...this.
	* gdb/target-delegates.c: Regenerate.
	* gdb/target.c (target_get_section_table): Make return type const.
	(target_section_by_addr): Likewise.  Also make some locals const.
	(memory_xfer_partial_1): Make some locals const.
	* gdb/target.h (struct target_ops) <get_section_table>: Make
	return type const.
	(target_section_by_addr): Likewise.
	(target_get_section_table): Likewise.

14 files changed, 69 insertions, 38 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 41e480a..e59343b 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,35 @@
 2021-02-24  Andrew Burgess  <andrew.burgess@embecosm.com>
 
+	* gdb/bfd-target.c (class target_bfd) <get_section_table>: Make
+	return type const.
+	* gdb/exec.c (struct exec_target) <get_section_table>: Likewise.
+	(section_table_read_available_memory): Make local const.
+	(exec_target::xfer_partial): Make local const.
+	(print_section_info): Make parameter const.
+	* gdb/exec.h (print_section_info): Likewise.
+	* gdb/ppc64-tdep.c (ppc64_convert_from_func_ptr_addr): Make local
+	const.
+	* gdb/record-btrace.c (record_btrace_target::xfer_partial):
+	Likewise.
+	* gdb/remote.c (remote_target::remote_xfer_live_readonly_partial):
+	Likewise.
+	* gdb/s390-tdep.c (s390_load): Likewise.
+	* gdb/solib-dsbt.c (scan_dyntag): Likewise.
+	* gdb/solib-svr4.c (scan_dyntag): Likewise.
+	* gdb/target-debug.h (target_debug_print_target_section_table_p):
+	Rename to...
+	(target_debug_print_const_target_section_table_p): ...this.
+	* gdb/target-delegates.c: Regenerate.
+	* gdb/target.c (target_get_section_table): Make return type const.
+	(target_section_by_addr): Likewise.  Also make some locals const.
+	(memory_xfer_partial_1): Make some locals const.
+	* gdb/target.h (struct target_ops) <get_section_table>: Make
+	return type const.
+	(target_section_by_addr): Likewise.
+	(target_get_section_table): Likewise.
+
+2021-02-24  Andrew Burgess  <andrew.burgess@embecosm.com>
+
 	* NEWS: Mention new 'maint info target-sections' command.
 	* maint.c (maintenance_info_target_sections): New function.
 	(_initialize_maint_cmds): Register new command.
diff --git a/gdb/bfd-target.c b/gdb/bfd-target.c
index 689dbb1..b23cf2c 100644
--- a/gdb/bfd-target.c
+++ b/gdb/bfd-target.c
@@ -50,7 +50,7 @@ public:
 		  ULONGEST offset, ULONGEST len,
 		  ULONGEST *xfered_len) override;
 
-  target_section_table *get_section_table () override;
+  const target_section_table *get_section_table () override;
 
 private:
   /* The BFD we're wrapping.  */
@@ -82,7 +82,7 @@ target_bfd::xfer_partial (target_object object,
     }
 }
 
-target_section_table *
+const target_section_table *
 target_bfd::get_section_table ()
 {
   return &m_table;
diff --git a/gdb/exec.c b/gdb/exec.c
index 68b3520..1cac5fb 100644
--- a/gdb/exec.c
+++ b/gdb/exec.c
@@ -75,7 +75,7 @@ struct exec_target final : public target_ops
 					const gdb_byte *writebuf,
 					ULONGEST offset, ULONGEST len,
 					ULONGEST *xfered_len) override;
-  target_section_table *get_section_table () override;
+  const target_section_table *get_section_table () override;
   void files_info () override;
 
   bool has_memory () override;
@@ -775,7 +775,7 @@ enum target_xfer_status
 section_table_read_available_memory (gdb_byte *readbuf, ULONGEST offset,
 				     ULONGEST len, ULONGEST *xfered_len)
 {
-  target_section_table *table = target_get_section_table (&exec_ops);
+  const target_section_table *table = target_get_section_table (&exec_ops);
   std::vector<mem_range> available_memory
     = section_table_available_memory (offset, len, *table);
 
@@ -884,7 +884,7 @@ section_table_xfer_memory_partial (gdb_byte *readbuf, const gdb_byte *writebuf,
   return TARGET_XFER_EOF;		/* We can't help.  */
 }
 
-target_section_table *
+const target_section_table *
 exec_target::get_section_table ()
 {
   return &current_program_space->target_sections;
@@ -896,7 +896,7 @@ exec_target::xfer_partial (enum target_object object,
 			   const gdb_byte *writebuf,
 			   ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
 {
-  target_section_table *table = get_section_table ();
+  const target_section_table *table = target_get_section_table (this);
 
   if (object == TARGET_OBJECT_MEMORY)
     return section_table_xfer_memory_partial (readbuf, writebuf,
@@ -908,7 +908,7 @@ exec_target::xfer_partial (enum target_object object,
 
 
 void
-print_section_info (target_section_table *t, bfd *abfd)
+print_section_info (const target_section_table *t, bfd *abfd)
 {
   struct gdbarch *gdbarch = gdbarch_from_bfd (abfd);
   /* FIXME: 16 is not wide enough when gdbarch_addr_bit > 64.  */
diff --git a/gdb/exec.h b/gdb/exec.h
index cccc0d0..1119953 100644
--- a/gdb/exec.h
+++ b/gdb/exec.h
@@ -96,7 +96,7 @@ extern void exec_set_section_address (const char *, int, CORE_ADDR);
    special cased --- it's filename is omitted; if it is the executable
    file, its entry point is printed.  */
 
-extern void print_section_info (target_section_table *table,
+extern void print_section_info (const target_section_table *table,
 				bfd *abfd);
 
 /* Helper function that attempts to open the symbol file at EXEC_FILE_HOST.
diff --git a/gdb/ppc64-tdep.c b/gdb/ppc64-tdep.c
index f8f6099..74873a6 100644
--- a/gdb/ppc64-tdep.c
+++ b/gdb/ppc64-tdep.c
@@ -561,7 +561,7 @@ ppc64_convert_from_func_ptr_addr (struct gdbarch *gdbarch,
 					struct target_ops *targ)
 {
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-  struct target_section *s = target_section_by_addr (targ, addr);
+  const struct target_section *s = target_section_by_addr (targ, addr);
 
   /* Check if ADDR points to a function descriptor.  */
   if (s && strcmp (s->the_bfd_section->name, ".opd") == 0)
diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index ac51ff2..d9cc7a3 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -1439,7 +1439,7 @@ record_btrace_target::xfer_partial (enum target_object object,
 	{
 	case TARGET_OBJECT_MEMORY:
 	  {
-	    struct target_section *section;
+	    const struct target_section *section;
 
 	    /* We do not allow writing memory in general.  */
 	    if (writebuf != NULL)
diff --git a/gdb/remote.c b/gdb/remote.c
index 31c6e17..2c85bdc 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -9044,7 +9044,7 @@ remote_target::remote_xfer_live_readonly_partial (gdb_byte *readbuf,
 						  int unit_size,
 						  ULONGEST *xfered_len)
 {
-  struct target_section *secp;
+  const struct target_section *secp;
 
   secp = target_section_by_addr (this, memaddr);
   if (secp != NULL
@@ -9052,8 +9052,8 @@ remote_target::remote_xfer_live_readonly_partial (gdb_byte *readbuf,
     {
       ULONGEST memend = memaddr + len;
 
-      target_section_table *table = target_get_section_table (this);
-      for (target_section &p : *table)
+      const target_section_table *table = target_get_section_table (this);
+      for (const target_section &p : *table)
 	{
 	  if (memaddr >= p.addr)
 	    {
diff --git a/gdb/s390-tdep.c b/gdb/s390-tdep.c
index 57ddd54..39c8ee0 100644
--- a/gdb/s390-tdep.c
+++ b/gdb/s390-tdep.c
@@ -684,8 +684,8 @@ s390_load (struct s390_prologue_data *data,
      we're analyzing the code to unwind past that frame.  */
   if (pv_is_constant (addr))
     {
-      struct target_section *secp;
-      secp = target_section_by_addr (current_top_target (), addr.k);
+      const struct target_section *secp
+	= target_section_by_addr (current_top_target (), addr.k);
       if (secp != NULL
 	  && (bfd_section_flags (secp->the_bfd_section) & SEC_READONLY))
 	return pv_constant (read_memory_integer (addr.k, size,
diff --git a/gdb/solib-dsbt.c b/gdb/solib-dsbt.c
index 71245b2..6d21806 100644
--- a/gdb/solib-dsbt.c
+++ b/gdb/solib-dsbt.c
@@ -424,7 +424,8 @@ scan_dyntag (int dyntag, bfd *abfd, CORE_ADDR *ptr)
     return 0;
 
   bool found = false;
-  for (target_section &target_section : current_program_space->target_sections)
+  for (const target_section &target_section
+	 : current_program_space->target_sections)
     if (sect == target_section.the_bfd_section)
       {
 	dyn_addr = target_section.addr;
diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c
index 5d0d380..f8dd419 100644
--- a/gdb/solib-svr4.c
+++ b/gdb/solib-svr4.c
@@ -610,7 +610,8 @@ scan_dyntag (const int desired_dyntag, bfd *abfd, CORE_ADDR *ptr,
     return 0;
 
   bool found = false;
-  for (target_section &target_section : current_program_space->target_sections)
+  for (const target_section &target_section
+	 : current_program_space->target_sections)
     if (sect == target_section.the_bfd_section)
       {
 	dyn_addr = target_section.addr;
diff --git a/gdb/target-debug.h b/gdb/target-debug.h
index 6910338..1cc8256 100644
--- a/gdb/target-debug.h
+++ b/gdb/target-debug.h
@@ -104,7 +104,7 @@
   target_debug_do_print (host_address_to_string (X))
 #define target_debug_print_struct_ui_file_p(X)	\
   target_debug_do_print (host_address_to_string (X))
-#define target_debug_print_target_section_table_p(X)	\
+#define target_debug_print_const_target_section_table_p(X)	\
   target_debug_do_print (host_address_to_string (X))
 #define target_debug_print_void_p(X) \
   target_debug_do_print (host_address_to_string (X))
diff --git a/gdb/target-delegates.c b/gdb/target-delegates.c
index 437b19b..69fbc0f 100644
--- a/gdb/target-delegates.c
+++ b/gdb/target-delegates.c
@@ -77,7 +77,7 @@ struct dummy_target : public target_ops
   void rcmd (const char *arg0, struct ui_file *arg1) override;
   char *pid_to_exec_file (int arg0) override;
   void log_command (const char *arg0) override;
-  target_section_table *get_section_table () override;
+  const target_section_table *get_section_table () override;
   thread_control_capabilities get_thread_control_capabilities () override;
   bool attach_no_wait () override;
   bool can_async_p () override;
@@ -248,7 +248,7 @@ struct debug_target : public target_ops
   void rcmd (const char *arg0, struct ui_file *arg1) override;
   char *pid_to_exec_file (int arg0) override;
   void log_command (const char *arg0) override;
-  target_section_table *get_section_table () override;
+  const target_section_table *get_section_table () override;
   thread_control_capabilities get_thread_control_capabilities () override;
   bool attach_no_wait () override;
   bool can_async_p () override;
@@ -2021,27 +2021,27 @@ debug_target::log_command (const char *arg0)
   fputs_unfiltered (")\n", gdb_stdlog);
 }
 
-target_section_table *
+const target_section_table *
 target_ops::get_section_table ()
 {
   return this->beneath ()->get_section_table ();
 }
 
-target_section_table *
+const target_section_table *
 dummy_target::get_section_table ()
 {
   return NULL;
 }
 
-target_section_table *
+const target_section_table *
 debug_target::get_section_table ()
 {
-  target_section_table * result;
+  const target_section_table * result;
   fprintf_unfiltered (gdb_stdlog, "-> %s->get_section_table (...)\n", this->beneath ()->shortname ());
   result = this->beneath ()->get_section_table ();
   fprintf_unfiltered (gdb_stdlog, "<- %s->get_section_table (", this->beneath ()->shortname ());
   fputs_unfiltered (") = ", gdb_stdlog);
-  target_debug_print_target_section_table_p (result);
+  target_debug_print_const_target_section_table_p (result);
   fputs_unfiltered ("\n", gdb_stdlog);
   return result;
 }
diff --git a/gdb/target.c b/gdb/target.c
index 06d7b4f..78535b8 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -812,7 +812,7 @@ target_read_string (CORE_ADDR memaddr, int len, int *bytes_read)
   return gdb::unique_xmalloc_ptr<char> ((char *) buffer.release ());
 }
 
-target_section_table *
+const target_section_table *
 target_get_section_table (struct target_ops *target)
 {
   return target->get_section_table ();
@@ -820,15 +820,15 @@ target_get_section_table (struct target_ops *target)
 
 /* Find a section containing ADDR.  */
 
-struct target_section *
+const struct target_section *
 target_section_by_addr (struct target_ops *target, CORE_ADDR addr)
 {
-  target_section_table *table = target_get_section_table (target);
+  const target_section_table *table = target_get_section_table (target);
 
   if (table == NULL)
     return NULL;
 
-  for (target_section &secp : *table)
+  for (const target_section &secp : *table)
     {
       if (addr >= secp.addr && addr < secp.endaddr)
 	return &secp;
@@ -965,7 +965,7 @@ memory_xfer_partial_1 (struct target_ops *ops, enum target_object object,
 
       if (pc_in_unmapped_range (memaddr, section))
 	{
-	  target_section_table *table = target_get_section_table (ops);
+	  const target_section_table *table = target_get_section_table (ops);
 	  const char *section_name = section->the_bfd_section->name;
 
 	  memaddr = overlay_mapped_address (memaddr, section);
@@ -984,13 +984,12 @@ memory_xfer_partial_1 (struct target_ops *ops, enum target_object object,
   /* Try the executable files, if "trust-readonly-sections" is set.  */
   if (readbuf != NULL && trust_readonly)
     {
-      struct target_section *secp;
-
-      secp = target_section_by_addr (ops, memaddr);
+      const struct target_section *secp
+	= target_section_by_addr (ops, memaddr);
       if (secp != NULL
 	  && (bfd_section_flags (secp->the_bfd_section) & SEC_READONLY))
 	{
-	  target_section_table *table = target_get_section_table (ops);
+	  const target_section_table *table = target_get_section_table (ops);
 	  return section_table_xfer_memory_partial (readbuf, writebuf,
 						    memaddr, len, xfered_len,
 						    *table);
diff --git a/gdb/target.h b/gdb/target.h
index 52e23b0..66d46e2 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -687,7 +687,7 @@ struct target_ops
       TARGET_DEFAULT_RETURN (NULL);
     virtual void log_command (const char *)
       TARGET_DEFAULT_IGNORE ();
-    virtual target_section_table *get_section_table ()
+    virtual const target_section_table *get_section_table ()
       TARGET_DEFAULT_RETURN (NULL);
 
     /* Provide default values for all "must have" methods.  */
@@ -2427,13 +2427,13 @@ extern CORE_ADDR target_translate_tls_address (struct objfile *objfile,
 					       CORE_ADDR offset);
 
 /* Return the "section" containing the specified address.  */
-struct target_section *target_section_by_addr (struct target_ops *target,
-					       CORE_ADDR addr);
+const struct target_section *target_section_by_addr (struct target_ops *target,
+						     CORE_ADDR addr);
 
 /* Return the target section table this target (or the targets
    beneath) currently manipulate.  */
 
-extern target_section_table *target_get_section_table
+extern const target_section_table *target_get_section_table
   (struct target_ops *target);
 
 /* From mem-break.c */