[PATCH 1/2] regdat.sh: generate const_target_desc_up for register descriptions

[Keith Seitz <keiths@redhat.com>]

Late last year, a patch propagated the use of target_desc unique
pointers (commit 1a5362ce51ef79ffb61caa20c93284dc368dc74a).  At the
time, the "old regformats/regdat.sh [weren't] changed because their
target_desc objects are statically allocated in the generated files."

Unfortunately that re-introduced ODR violations on ppc64le:

CXXLD  gdbserver
../../src/gdbserver/../gdb/arch/ppc-linux-tdesc.h:46:29: error: ‘tdesc_powerpc_isa207_htm_vsx64l’ violates the C++ One Definition Rule [-Werror=odr]
   46 | extern const_target_desc_up tdesc_powerpc_isa207_htm_vsx64l;
      |                             ^
powerpc-isa207-htm-vsx64l-generated.cc:26:27: note: ‘tdesc_powerpc_isa207_htm_vsx64l’ was previously declared here
   26 | const struct target_desc *tdesc_powerpc_isa207_htm_vsx64l;
      |                           ^
powerpc-isa207-htm-vsx64l-generated.cc:26:27: note: code may be misoptimized unless ‘-fno-strict-aliasing’ is used

Update regdat.sh so that generated init_registers_* code matches the
const-unique_ptr-based target description API, resolving the ODR violation.

A follow-up patch updates various gdbserver architectures to
accommodate this API change.

Tested on ppc64le and s390x Fedora 43 and mips-linux
cross build (all with LTO).

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28444
---
 gdb/regformats/regdat.sh | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/gdb/regformats/regdat.sh b/gdb/regformats/regdat.sh
index aeb41f6b7ad..af2bdc28810 100755
--- a/gdb/regformats/regdat.sh
+++ b/gdb/regformats/regdat.sh
@@ -125,7 +125,7 @@ do
   if test "${type}" = "name"; then
     name="${entry}"
 
-    echo "const struct target_desc *tdesc_${name};"
+    echo "const_target_desc_up tdesc_${name};"
     echo ""
 
     # This is necessary for -Wmissing-declarations.
@@ -134,9 +134,8 @@ do
     echo "void"
     echo "init_registers_${name} (void)"
     echo "{"
-    echo "  static struct target_desc tdesc_${name}_s;"
-    echo "  struct target_desc *result = &tdesc_${name}_s;"
-    echo "  struct tdesc_feature *feature = tdesc_create_feature (result, \"${name}\");"
+    echo "  target_desc_up result = allocate_target_description ();"
+    echo "  struct tdesc_feature *feature = tdesc_create_feature (result.get (), \"${name}\");"
     continue
   elif test "${type}" = "xmltarget"; then
     xmltarget="${entry}"
@@ -195,12 +194,12 @@ echo
 osabi_enum=$(grep "${osabi}" "$2" | sed 's/.*(\([^,]\+\),.*/GDB_OSABI_\1/')
 
 cat <<EOF
-  result->xmltarget = xmltarget_${name};
+  result.get ()->xmltarget = xmltarget_${name};
 #endif
 
-  init_target_desc (result, expedite_regs_${name}, ${osabi_enum});
+  init_target_desc (result.get (), expedite_regs_${name}, ${osabi_enum});
 
-  tdesc_${name} = result;
+  tdesc_${name} = std::move (result);
 }
 EOF
 
-- 
2.53.0