target_stack -> current_top_target() throughout

The recent C++ification of target_ops replaced references to the old
"current_target" squashed target throughout with references to a
"target_stack" pointer.  I had picked the "target_stack" name very
early in the multi-target work, and managed to stick with it, even
though it's a bit of a misnomer, since it isn't really a "target
stack" object, but a pointer into the current top target in the stack.
As I'm splitting more pieces off of the multi-target branch, I've come
to think that it's better to rename it now.  A following patch will
introduce a new class to represent a target stack, and "target_stack"
would be _its_ ideal name.  (In the branch, the class is called
a_target_stack to work around the clash.)

Thus this commit renames target_stack to current_top_target and
replaces all references throughout.  Also, while at it,
current_top_target is made a function instead of a pointer, to make it
possible to change its internal implementation without leaking
implementation details out.  In a couple patches, the implementation
of the function will change to refer to a target stack object, and
then further down the multi-target work, it'll change again to find
the right target stack for the current inferior.

gdb/ChangeLog:
2018-06-07  Pedro Alves  <palves@redhat.com>

	* target.h (target_stack): Delete.
	(current_top_target): Declare function.
	* target.c (target_stack): Delete.
	(g_current_top_target): New.
	(current_top_target): New function.
	* auxv.c: Use current_top_target instead of target_stack
	throughout.
	* avr-tdep.c: Likewise.
	* breakpoint.c: Likewise.
	* corefile.c: Likewise.
	* elfread.c: Likewise.
	* eval.c: Likewise.
	* exceptions.c: Likewise.
	* frame.c: Likewise.
	* gdbarch-selftests.c: Likewise.
	* gnu-v3-abi.c: Likewise.
	* ia64-tdep.c: Likewise.
	* ia64-vms-tdep.c: Likewise.
	* infcall.c: Likewise.
	* infcmd.c: Likewise.
	* infrun.c: Likewise.
	* linespec.c: Likewise.
	* linux-tdep.c: Likewise.
	* minsyms.c: Likewise.
	* ppc-linux-nat.c: Likewise.
	* ppc-linux-tdep.c: Likewise.
	* procfs.c: Likewise.
	* regcache.c: Likewise.
	* remote.c: Likewise.
	* rs6000-tdep.c: Likewise.
	* s390-linux-nat.c: Likewise.
	* s390-tdep.c: Likewise.
	* solib-aix.c: Likewise.
	* solib-darwin.c: Likewise.
	* solib-dsbt.c: Likewise.
	* solib-spu.c: Likewise.
	* solib-svr4.c: Likewise.
	* solib-target.c: Likewise.
	* sparc-tdep.c: Likewise.
	* sparc64-tdep.c: Likewise.
	* spu-tdep.c: Likewise.
	* symfile.c: Likewise.
	* symtab.c: Likewise.
	* target-descriptions.c: Likewise.
	* target-memory.c: Likewise.
	* target.c: Likewise.
	* target.h: Likewise.
	* tracefile-tfile.c: Likewise.
	* tracepoint.c: Likewise.
	* valops.c: Likewise.
	* valprint.c: Likewise.
	* value.c: Likewise.
	* windows-tdep.c: Likewise.
	* mi/mi-main.c: Likewise.

1 files changed, 12 insertions, 11 deletions

diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c
index f9936b3..d012f08 100644
--- a/gdb/solib-svr4.c
+++ b/gdb/solib-svr4.c
@@ -432,11 +432,11 @@ read_program_header (int type, int *p_sect_size, int *p_arch_size,
   int pt_phdr_p = 0;
 
   /* Get required auxv elements from target.  */
-  if (target_auxv_search (target_stack, AT_PHDR, &at_phdr) <= 0)
+  if (target_auxv_search (current_top_target (), AT_PHDR, &at_phdr) <= 0)
     return 0;
-  if (target_auxv_search (target_stack, AT_PHENT, &at_phent) <= 0)
+  if (target_auxv_search (current_top_target (), AT_PHENT, &at_phent) <= 0)
     return 0;
-  if (target_auxv_search (target_stack, AT_PHNUM, &at_phnum) <= 0)
+  if (target_auxv_search (current_top_target (), AT_PHNUM, &at_phnum) <= 0)
     return 0;
   if (!at_phdr || !at_phnum)
     return 0;
@@ -1244,7 +1244,7 @@ svr4_current_sos_via_xfer_libraries (struct svr4_library_list *list,
 
   /* Fetch the list of shared libraries.  */
   gdb::optional<gdb::char_vector> svr4_library_document
-    = target_read_stralloc (target_stack, TARGET_OBJECT_LIBRARIES_SVR4,
+    = target_read_stralloc (current_top_target (), TARGET_OBJECT_LIBRARIES_SVR4,
 			    annex);
   if (!svr4_library_document)
     return 0;
@@ -2217,9 +2217,10 @@ enable_break (struct svr4_info *info, int from_tty)
       struct obj_section *os;
 
       sym_addr = gdbarch_addr_bits_remove
-	(target_gdbarch (), gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
-							     sym_addr,
-							     target_stack));
+	(target_gdbarch (),
+	 gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
+					     sym_addr,
+					     current_top_target ()));
 
       /* On at least some versions of Solaris there's a dynamic relocation
 	 on _r_debug.r_brk and SYM_ADDR may not be relocated yet, e.g., if
@@ -2334,7 +2335,7 @@ enable_break (struct svr4_info *info, int from_tty)
       /* If we were not able to find the base address of the loader
          from our so_list, then try using the AT_BASE auxilliary entry.  */
       if (!load_addr_found)
-	if (target_auxv_search (target_stack, AT_BASE, &load_addr) > 0)
+	if (target_auxv_search (current_top_target (), AT_BASE, &load_addr) > 0)
 	  {
 	    int addr_bit = gdbarch_addr_bit (target_gdbarch ());
 
@@ -2459,7 +2460,7 @@ enable_break (struct svr4_info *info, int from_tty)
 	  sym_addr = BMSYMBOL_VALUE_ADDRESS (msymbol);
 	  sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
 							 sym_addr,
-							 target_stack);
+							 current_top_target ());
 	  svr4_create_solib_event_breakpoints (target_gdbarch (), sym_addr);
 	  return 1;
 	}
@@ -2476,7 +2477,7 @@ enable_break (struct svr4_info *info, int from_tty)
 	      sym_addr = BMSYMBOL_VALUE_ADDRESS (msymbol);
 	      sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
 							     sym_addr,
-							     target_stack);
+							     current_top_target ());
 	      svr4_create_solib_event_breakpoints (target_gdbarch (), sym_addr);
 	      return 1;
 	    }
@@ -2571,7 +2572,7 @@ svr4_exec_displacement (CORE_ADDR *displacementp)
   if ((bfd_get_file_flags (exec_bfd) & DYNAMIC) == 0)
     return 0;
 
-  if (target_auxv_search (target_stack, AT_ENTRY, &entry_point) <= 0)
+  if (target_auxv_search (current_top_target (), AT_ENTRY, &entry_point) <= 0)
     return 0;
 
   exec_displacement = entry_point - bfd_get_start_address (exec_bfd);