[PATCH] Handle ghost entities in symbol lookup

[Tom Tromey <tromey@adacore.com>]

Normally, SPARK ghost entities are removed from the executable.
However, with -gnata, they will be preserved.  In this situation, it's
handy to be able to inspect them.  This patch allows this by removing
the "___ghost_" prefix in the appropriate places.
---
 gdb/ada-lang.c                       | 12 +++++++++
 gdb/testsuite/gdb.ada/ghost.exp      | 37 ++++++++++++++++++++++++++++
 gdb/testsuite/gdb.ada/ghost/gpck.ads | 18 ++++++++++++++
 gdb/testsuite/gdb.ada/ghost/main.adb | 22 +++++++++++++++++
 gdb/testsuite/gdb.ada/ghost/pck.ads  | 19 ++++++++++++++
 5 files changed, 108 insertions(+)
 create mode 100644 gdb/testsuite/gdb.ada/ghost.exp
 create mode 100644 gdb/testsuite/gdb.ada/ghost/gpck.ads
 create mode 100644 gdb/testsuite/gdb.ada/ghost/main.adb
 create mode 100644 gdb/testsuite/gdb.ada/ghost/pck.ads

diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index 0f772fd7b46..71757e6ee2a 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -1323,6 +1323,11 @@ ada_decode (const char *encoded, bool wrap)
      if we see this prefix.  */
   if (startswith (encoded, "_ada_"))
     encoded += 5;
+  /* The "___ghost_" prefix is used for ghost entities.  Normally
+     these aren't preserved but when they are, it's useful to see
+     them.  */
+  if (startswith (encoded, "___ghost_"))
+    encoded += 9;
 
   /* If the name starts with '_', then it is not a properly encoded
      name, so do not attempt to decode it.  Similarly, if the name
@@ -6016,6 +6021,9 @@ wild_match (const char *name, const char *patn)
   const char *p;
   const char *name0 = name;
 
+  if (startswith (name, "___ghost_"))
+    name += 9;
+
   while (1)
     {
       const char *match = name;
@@ -13193,6 +13201,10 @@ do_full_match (const char *symbol_search_name,
   if (startswith (symbol_search_name, "_ada_")
       && !startswith (lname, "_ada"))
     symbol_search_name += 5;
+  /* Likewise for ghost entities.  */
+  if (startswith (symbol_search_name, "___ghost_")
+      && !startswith (lname, "___ghost_"))
+    symbol_search_name += 9;
 
   int uscore_count = 0;
   while (*lname != '\0')
diff --git a/gdb/testsuite/gdb.ada/ghost.exp b/gdb/testsuite/gdb.ada/ghost.exp
new file mode 100644
index 00000000000..7f92b130eff
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/ghost.exp
@@ -0,0 +1,37 @@
+# Copyright 2022 Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+load_lib "ada.exp"
+
+if { [skip_ada_tests] } { return -1 }
+
+standard_ada_testfile main
+
+set flags [list debug additional_flags=-gnata]
+if {[gdb_compile_ada "${srcfile}" "${binfile}" executable $flags] != "" } {
+  return -1
+}
+
+clean_restart ${testfile}
+
+set bp_location [gdb_get_line_number "START" ${testdir}/main.adb]
+if ![runto "main.adb:$bp_location" ] then {
+  perror "Couldn't run ${testfile}"
+  return
+}
+
+gdb_test "print value" " = 64 '@'"
+gdb_test "print ghost_value" " = 64 '@'"
+gdb_test "print value2" " = 33 '!'"
diff --git a/gdb/testsuite/gdb.ada/ghost/gpck.ads b/gdb/testsuite/gdb.ada/ghost/gpck.ads
new file mode 100644
index 00000000000..5a38ed4f94e
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/ghost/gpck.ads
@@ -0,0 +1,18 @@
+--  Copyright 2022 Free Software Foundation, Inc.
+--
+--  This program is free software; you can redistribute it and/or modify
+--  it under the terms of the GNU General Public License as published by
+--  the Free Software Foundation; either version 3 of the License, or
+--  (at your option) any later version.
+--
+--  This program is distributed in the hope that it will be useful,
+--  but WITHOUT ANY WARRANTY; without even the implied warranty of
+--  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+--  GNU General Public License for more details.
+--
+--  You should have received a copy of the GNU General Public License
+--  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package GPck with Ghost is
+   Value2 : Character := '!';
+end GPck;
diff --git a/gdb/testsuite/gdb.ada/ghost/main.adb b/gdb/testsuite/gdb.ada/ghost/main.adb
new file mode 100644
index 00000000000..7da25422071
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/ghost/main.adb
@@ -0,0 +1,22 @@
+--  Copyright 2022 Free Software Foundation, Inc.
+--
+--  This program is free software; you can redistribute it and/or modify
+--  it under the terms of the GNU General Public License as published by
+--  the Free Software Foundation; either version 3 of the License, or
+--  (at your option) any later version.
+--
+--  This program is distributed in the hope that it will be useful,
+--  but WITHOUT ANY WARRANTY; without even the implied warranty of
+--  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+--  GNU General Public License for more details.
+--
+--  You should have received a copy of the GNU General Public License
+--  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+with Pck; use Pck;
+with GPck; use GPck;
+
+procedure Main with Ghost is
+begin
+   null;                        -- START
+end Main;
diff --git a/gdb/testsuite/gdb.ada/ghost/pck.ads b/gdb/testsuite/gdb.ada/ghost/pck.ads
new file mode 100644
index 00000000000..f56aa509822
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/ghost/pck.ads
@@ -0,0 +1,19 @@
+--  Copyright 2022 Free Software Foundation, Inc.
+--
+--  This program is free software; you can redistribute it and/or modify
+--  it under the terms of the GNU General Public License as published by
+--  the Free Software Foundation; either version 3 of the License, or
+--  (at your option) any later version.
+--
+--  This program is distributed in the hope that it will be useful,
+--  but WITHOUT ANY WARRANTY; without even the implied warranty of
+--  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+--  GNU General Public License for more details.
+--
+--  You should have received a copy of the GNU General Public License
+--  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package Pck is
+   Value : Character := '@';
+   Ghost_Value : Character := '@' with Ghost;
+end Pck;
-- 
2.34.1