[binutils-gdb] gdb: make regcache's cooked_write_test selftest work with native-extended-gdbserver board

[Simon Marchi <simark@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=d890c720b8c4daf8892a175296d8e88ec992c92d

commit d890c720b8c4daf8892a175296d8e88ec992c92d
Author: Simon Marchi <simon.marchi@efficios.com>
Date:   Thu May 5 09:54:59 2022 -0400

    gdb: make regcache's cooked_write_test selftest work with native-extended-gdbserver board
    
    Running
    
        $ make check TESTS="gdb.gdb/unittest.exp" RUNTESTFLAGS="--target_board=native-extended-gdbserver"
    
    I get some failures:
    
        Running selftest regcache::cooked_write_test::i386.^M
        Self test failed: target already pushed^M
        Running selftest regcache::cooked_write_test::i386:intel.^M
        Self test failed: target already pushed^M
        Running selftest regcache::cooked_write_test::i386:x64-32.^M
        Self test failed: target already pushed^M
        Running selftest regcache::cooked_write_test::i386:x64-32:intel.^M
        Self test failed: target already pushed^M
        Running selftest regcache::cooked_write_test::i386:x86-64.^M
        Self test failed: target already pushed^M
        Running selftest regcache::cooked_write_test::i386:x86-64:intel.^M
        Self test failed: target already pushed^M
        Running selftest regcache::cooked_write_test::i8086.^M
        Self test failed: target already pushed^M
    
    This is because the native-extended-gdbserver automatically connects GDB
    to a GDBserver on startup, and therefore pushes a remote target on the
    initial inferior.  cooked_write_test is currently written in a way that
    errors out if the current inferior has a process_stratum_target pushed.
    
    Rewrite it to use scoped_mock_context, so it doesn't depend on the
    current inferior (the current one upon entering the function).
    
    Change-Id: I0357f989eacbdecc4bf88b043754451b476052ad

Diff:
---
 gdb/regcache.c | 25 ++-----------------------
 1 file changed, 2 insertions(+), 23 deletions(-)

diff --git a/gdb/regcache.c b/gdb/regcache.c
index a5e83da1ca4..037659ef8fa 100644
--- a/gdb/regcache.c
+++ b/gdb/regcache.c
@@ -1944,30 +1944,9 @@ cooked_read_test (struct gdbarch *gdbarch)
 static void
 cooked_write_test (struct gdbarch *gdbarch)
 {
-  /* Error out if debugging something, because we're going to push the
-     test target, which would pop any existing target.  */
-  if (current_inferior ()->top_target ()->stratum () >= process_stratum)
-    error (_("target already pushed"));
-
   /* Create a mock environment.  A process_stratum target pushed.  */
-
-  target_ops_no_register mock_target;
-
-  /* Push the process_stratum target so we can mock accessing
-     registers.  */
-  current_inferior ()->push_target (&mock_target);
-
-  /* Pop it again on exit (return/exception).  */
-  struct on_exit
-  {
-    ~on_exit ()
-    {
-      pop_all_targets_at_and_above (process_stratum);
-    }
-  } pop_targets;
-
-  readwrite_regcache readwrite (&mock_target, gdbarch);
-
+  scoped_mock_context<target_ops_no_register> ctx (gdbarch);
+  readwrite_regcache readwrite (&ctx.mock_target, gdbarch);
   const int num_regs = gdbarch_num_cooked_regs (gdbarch);
 
   for (auto regnum = 0; regnum < num_regs; regnum++)