Restructure how gdbarch.py generates the verify_gdbarch function.
Previously the postdefault handling was bundled together with the
validation. This means that a field can't have both a postdefault,
and set its invalid attribute to a string.
This doesn't seem reasonable to me, I see no reason why a field can't
have both a postdefault (used when the tdep doesn't set the field),
and an invalid expression, which can be used to validate the value
that a tdep might set.
In this commit I restructure the verify_gdbarch generation code to
allow the above, there is no change in the actual generated code in
this commit, that will come in later commit.
---
gdb/gdbarch.py | 42 +++++++++++++++++++++++++--------------
gdb/gdbarch_components.py | 40 ++++++++++++++++---------------------
2 files changed, 44 insertions(+), 38 deletions(-)
@@ -203,35 +203,47 @@ with open("gdbarch.c", "w") as f:
file=f,
)
for c in filter(not_info, components):
+ # An opportunity to write in the 'postdefault' value. We
+ # change field's value to the postdefault if its current value
+ # is not different to the initial value of the field.
+ if c.postdefault is not None:
+ init_value = c.predefault or "0"
+ print(f" if (gdbarch->{c.name} == {init_value})", file=f)
+ print(f" gdbarch->{c.name} = {c.postdefault};", file=f)
+
+ # Now validate the value.
if c.invalid is False:
print(f" /* Skip verify of {c.name}, invalid_p == 0 */", file=f)
elif c.predicate:
print(f" /* Skip verify of {c.name}, has predicate. */", file=f)
- elif isinstance(c.invalid, str) and c.postdefault is not None:
- print(f" if ({c.invalid})", file=f)
- print(f" gdbarch->{c.name} = {c.postdefault};", file=f)
- elif c.predefault is not None and c.postdefault is not None:
- print(f" if (gdbarch->{c.name} == {c.predefault})", file=f)
- print(f" gdbarch->{c.name} = {c.postdefault};", file=f)
- elif c.postdefault is not None:
- print(f" if (gdbarch->{c.name} == 0)", file=f)
- print(f" gdbarch->{c.name} = {c.postdefault};", file=f)
+ elif c.invalid is None:
+ # No validation has been requested for this component.
+ pass
elif isinstance(c.invalid, str):
print(f" if ({c.invalid})", file=f)
print(f""" log.puts ("\\n\\t{c.name}");""", file=f)
- elif c.predefault is not None:
- print(f" if (gdbarch->{c.name} == {c.predefault})", file=f)
- print(f""" log.puts ("\\n\\t{c.name}");""", file=f)
elif c.invalid is True:
- print(f" if (gdbarch->{c.name} == 0)", file=f)
- print(f""" log.puts ("\\n\\t{c.name}");""", file=f)
+ if c.postdefault is not None:
+ # This component has its 'invalid' field set to True, but
+ # also has a postdefault. This makes no sense, the
+ # postdefault will have been applied above, so this field
+ # will not have a zero value.
+ raise Exception(
+ f"component {c.name} has postdefault and invalid set to True"
+ )
+ else:
+ init_value = c.predefault or "0"
+ print(f" if (gdbarch->{c.name} == {init_value})", file=f)
+ print(f""" log.puts ("\\n\\t{c.name}");""", file=f)
else:
# We should not allow ourselves to simply do nothing here
# because no other case applies. If we end up here then
# either the input data needs adjusting so one of the
# above cases matches, or we need additional cases adding
# here.
- raise Exception("unhandled case when generating gdbarch validation")
+ raise Exception(
+ f"unhandled case when generating gdbarch validation: {c.name}"
+ )
print(" if (!log.empty ())", file=f)
print(
""" internal_error (_("verify_gdbarch: the following are invalid ...%s"),""",
@@ -63,34 +63,28 @@
# * "predefault", "postdefault", and "invalid" - These are used for
# the initialization and verification steps:
#
-# A gdbarch is zero-initialized. Then, if a field has a pre-default,
-# the field is set to that value. After initialization is complete
-# (that is, after the tdep code has a chance to change the settings),
-# the post-initialization step is done.
+# A gdbarch is zero-initialized. Then, if a field has a "predefault",
+# the field is set to that value. This becomes the field's initial
+# value.
#
-# There is a generic algorithm to generate a "validation function" for
-# all fields. If the field has an "invalid" attribute with a string
-# value, then this string is the expression (note that a string-valued
-# "invalid" and "predicate" are mutually exclusive; and the case where
-# invalid is True means to ignore this field and instead use the
-# default checking that is about to be described). Otherwise, if
-# there is a "predefault", then the field is valid if it differs from
-# the predefault. Otherwise, the check is done against 0 (really NULL
-# for function pointers, but same idea).
-#
-# In post-initialization / validation, there are several cases.
+# After initialization is complete (that is, after the tdep code has a
+# chance to change the settings), the post-initialization step is
+# done.
#
-# * If "invalid" is False, or if the field specifies "predicate",
-# validation is skipped. Otherwise, a validation step is emitted.
+# If the field still has its initial value (see above), and the field
+# has a "postdefault", then the field is set to this value.
#
-# * Otherwise, the validity is checked using the usual validation
-# function (see above). If the field is considered valid, nothing is
-# done.
+# After the possible "postdefault" assignment, validation is
+# performed for fields that don't have a "predicate".
#
-# * Otherwise, the field's value is invalid. If there is a
-# "postdefault", then the field is assigned that value.
+# If the field has an "invalid" attribute with a string value, then
+# this string is the expression that should evaluate to true when the
+# field is invalid.
#
-# * Otherwise, the gdbarch will fail validation and gdb will crash.
+# Otherwise, if "invalid" is True, then the generic validation
+# function is used: the field is considered invalid it still contains
+# its default value. This validation is what is used within the _p
+# predicate function if the field has "predicate" set to True.
#
# Function and Method share:
#