[PATCH 3/9] Don't emit gdbarch_return_value

[Tom Tromey <tromey@adacore.com>]

The previous patch introduced a new overload of gdbarch_return_value.
The intent here is that this new overload always be called by the core
of gdb -- the previous implementation is effectively deprecated,
because a call to the old-style method will not work with any
converted architectures (whereas calling the new-style method is will
delegate when needed).

This patch changes gdbarch.py so that the old gdbarch_return_value
wrapper function can be omitted.  This will prevent any errors from
creeping in.
---
 gdb/arch-utils.c          | 36 ++++++++++----------
 gdb/gdbarch-components.py |  6 ++++
 gdb/gdbarch-gen.h         |  1 -
 gdb/gdbarch.c             | 10 ------
 gdb/gdbarch.py            | 70 +++++++++++++++++++++------------------
 5 files changed, 61 insertions(+), 62 deletions(-)

diff --git a/gdb/arch-utils.c b/gdb/arch-utils.c
index 677e405fd6c..cce0bf809f5 100644
--- a/gdb/arch-utils.c
+++ b/gdb/arch-utils.c
@@ -1092,24 +1092,6 @@ default_read_core_file_mappings
 {
 }
 
-enum return_value_convention
-default_gdbarch_return_value
-     (struct gdbarch *gdbarch, struct value *function, struct type *valtype,
-      struct regcache *regcache, struct value **read_value,
-      const gdb_byte *writebuf)
-{
-  gdb_byte *readbuf = nullptr;
-
-  if (read_value != nullptr)
-    {
-      *read_value = allocate_value (valtype);
-      readbuf = value_contents_raw (*read_value).data ();
-    }
-
-  return gdbarch_return_value (gdbarch, function, valtype, regcache,
-			       readbuf, writebuf);
-}
-
 /* Non-zero if we want to trace architecture code.  */
 
 #ifndef GDBARCH_DEBUG
@@ -1180,6 +1162,24 @@ pstring_list (const char *const *list)
 
 #include "gdbarch.c"
 
+enum return_value_convention
+default_gdbarch_return_value
+     (struct gdbarch *gdbarch, struct value *function, struct type *valtype,
+      struct regcache *regcache, struct value **read_value,
+      const gdb_byte *writebuf)
+{
+  gdb_byte *readbuf = nullptr;
+
+  if (read_value != nullptr)
+    {
+      *read_value = allocate_value (valtype);
+      readbuf = value_contents_raw (*read_value).data ();
+    }
+
+  return gdbarch->return_value (gdbarch, function, valtype, regcache,
+				readbuf, writebuf);
+}
+
 obstack *gdbarch_obstack (gdbarch *arch)
 {
   return &arch->obstack;
diff --git a/gdb/gdbarch-components.py b/gdb/gdbarch-components.py
index 844eb4f161d..3b0f62e334d 100644
--- a/gdb/gdbarch-components.py
+++ b/gdb/gdbarch-components.py
@@ -113,6 +113,9 @@
 # 'result' can be used to reference the result of the function/method
 # implementation.  The 'result_checks' can only be used if the 'type'
 # of this Function/Method is not 'void'.
+#
+# * "implement" - optional, a boolean.  If True (the default), a
+# wrapper function for this function will be emitted.
 
 Info(
     type="const struct bfd_arch_info *",
@@ -868,6 +871,9 @@ method can properly handle variably-sized types.
         ("const gdb_byte *", "writebuf"),
     ],
     invalid=False,
+    # We don't want to accidentally introduce calls to this, as gdb
+    # should only ever call return_value_new (see below).
+    implement=False,
 )
 
 Method(
diff --git a/gdb/gdbarch-gen.h b/gdb/gdbarch-gen.h
index 4ec11fd4eee..059865e86f7 100644
--- a/gdb/gdbarch-gen.h
+++ b/gdb/gdbarch-gen.h
@@ -439,7 +439,6 @@ extern void set_gdbarch_integer_to_address (struct gdbarch *gdbarch, gdbarch_int
    method can properly handle variably-sized types. */
 
 typedef enum return_value_convention (gdbarch_return_value_ftype) (struct gdbarch *gdbarch, struct value *function, struct type *valtype, struct regcache *regcache, gdb_byte *readbuf, const gdb_byte *writebuf);
-extern enum return_value_convention gdbarch_return_value (struct gdbarch *gdbarch, struct value *function, struct type *valtype, struct regcache *regcache, gdb_byte *readbuf, const gdb_byte *writebuf);
 extern void set_gdbarch_return_value (struct gdbarch *gdbarch, gdbarch_return_value_ftype *return_value);
 
 /* Return the return-value convention that will be used by FUNCTION
diff --git a/gdb/gdbarch.c b/gdb/gdbarch.c
index 911aa0ec277..3c7e99e0874 100644
--- a/gdb/gdbarch.c
+++ b/gdb/gdbarch.c
@@ -2664,16 +2664,6 @@ set_gdbarch_integer_to_address (struct gdbarch *gdbarch,
   gdbarch->integer_to_address = integer_to_address;
 }
 
-enum return_value_convention
-gdbarch_return_value (struct gdbarch *gdbarch, struct value *function, struct type *valtype, struct regcache *regcache, gdb_byte *readbuf, const gdb_byte *writebuf)
-{
-  gdb_assert (gdbarch != NULL);
-  gdb_assert (gdbarch->return_value != NULL);
-  if (gdbarch_debug >= 2)
-    gdb_printf (gdb_stdlog, "gdbarch_return_value called\n");
-  return gdbarch->return_value (gdbarch, function, valtype, regcache, readbuf, writebuf);
-}
-
 void
 set_gdbarch_return_value (struct gdbarch *gdbarch,
                           gdbarch_return_value_ftype return_value)
diff --git a/gdb/gdbarch.py b/gdb/gdbarch.py
index da848feae84..df01dd11c05 100755
--- a/gdb/gdbarch.py
+++ b/gdb/gdbarch.py
@@ -119,6 +119,7 @@ class Function(_Component):
         printer=None,
         param_checks=None,
         result_checks=None,
+        implement=True,
     ):
         super().__init__(
             comment=comment,
@@ -132,6 +133,7 @@ class Function(_Component):
             params=params,
             param_checks=param_checks,
             result_checks=result_checks,
+            implement=implement,
         )
 
     def ftype(self):
@@ -246,10 +248,11 @@ with open("gdbarch-gen.h", "w") as f:
                 f"typedef {c.type} ({c.ftype()}) ({c.param_list()});",
                 file=f,
             )
-            print(
-                f"extern {c.type} gdbarch_{c.name} ({c.set_list()});",
-                file=f,
-            )
+            if c.implement:
+                print(
+                    f"extern {c.type} gdbarch_{c.name} ({c.set_list()});",
+                    file=f,
+                )
             print(
                 f"extern void set_gdbarch_{c.name} (struct gdbarch *gdbarch, {c.ftype()} *{c.name});",
                 file=f,
@@ -441,38 +444,39 @@ with open("gdbarch.c", "w") as f:
             print(f"  return {c.get_predicate()};", file=f)
             print("}", file=f)
         if isinstance(c, Function):
-            print(file=f)
-            print(f"{c.type}", file=f)
-            print(f"gdbarch_{c.name} ({c.set_list()})", file=f)
-            print("{", file=f)
-            print("  gdb_assert (gdbarch != NULL);", file=f)
-            print(f"  gdb_assert (gdbarch->{c.name} != NULL);", file=f)
-            if c.predicate and c.predefault:
-                # Allow a call to a function with a predicate.
+            if c.implement:
+                print(file=f)
+                print(f"{c.type}", file=f)
+                print(f"gdbarch_{c.name} ({c.set_list()})", file=f)
+                print("{", file=f)
+                print("  gdb_assert (gdbarch != NULL);", file=f)
+                print(f"  gdb_assert (gdbarch->{c.name} != NULL);", file=f)
+                if c.predicate and c.predefault:
+                    # Allow a call to a function with a predicate.
+                    print(
+                        f"  /* Do not check predicate: {c.get_predicate()}, allow call.  */",
+                        file=f,
+                    )
+                if c.param_checks:
+                    for rule in c.param_checks:
+                        print(f"  gdb_assert ({rule});", file=f)
+                print("  if (gdbarch_debug >= 2)", file=f)
                 print(
-                    f"  /* Do not check predicate: {c.get_predicate()}, allow call.  */",
+                    f"""    gdb_printf (gdb_stdlog, "gdbarch_{c.name} called\\n");""",
                     file=f,
                 )
-            if c.param_checks:
-                for rule in c.param_checks:
-                    print(f"  gdb_assert ({rule});", file=f)
-            print("  if (gdbarch_debug >= 2)", file=f)
-            print(
-                f"""    gdb_printf (gdb_stdlog, "gdbarch_{c.name} called\\n");""",
-                file=f,
-            )
-            print("  ", file=f, end="")
-            if c.type != "void":
-                if c.result_checks:
-                    print("auto result = ", file=f, end="")
-                else:
-                    print("return ", file=f, end="")
-            print(f"gdbarch->{c.name} ({c.actuals()});", file=f)
-            if c.type != "void" and c.result_checks:
-                for rule in c.result_checks:
-                    print(f"  gdb_assert ({rule});", file=f)
-                print("  return result;", file=f)
-            print("}", file=f)
+                print("  ", file=f, end="")
+                if c.type != "void":
+                    if c.result_checks:
+                        print("auto result = ", file=f, end="")
+                    else:
+                        print("return ", file=f, end="")
+                print(f"gdbarch->{c.name} ({c.actuals()});", file=f)
+                if c.type != "void" and c.result_checks:
+                    for rule in c.result_checks:
+                        print(f"  gdb_assert ({rule});", file=f)
+                    print("  return result;", file=f)
+                print("}", file=f)
             print(file=f)
             print("void", file=f)
             print(f"set_gdbarch_{c.name} (struct gdbarch *gdbarch,", file=f)
-- 
2.34.3