[PATCH v3 4/9] gdb/jit: apply some simplifications and assertions
Tankut Baris Aktemur
tankut.baris.aktemur@intel.com
Wed Jul 15 08:16:32 GMT 2020
From: Simon Marchi <simon.marchi@polymtl.ca>
Following patch "gdb/jit: split jit_objfile_data in two", there are some
simplifications we can make. The invariants described there mean that
we can assume / assert some things instead of checking them using
conditionals.
If an instance of jiter_objfile_data exists for a given objfile, it's
because the required JIT interface symbols were found. Therefore, in
~jiter_objfile_data, the `register_code` field can't be NULL. It was
previously used to differentiate a jit_objfile_data object used for a
JITer vs a JITed. We can remove that check.
If an instance of jiter_objfile_data exists for a given objfile, it's
because it's the sole JITer objfile in the scope of its program space
(jit_program_space_data::objfile points to it). At the moment,
jit_breakpoint_re_set_internal won't create a second instance of
jiter_objfile_data for a given program space. Therefore, it's not
necessary to check for `ps_data != NULL` in ~jiter_objfile_data: we know
a jit_program_space_data for that program space exists. We also don't
need to check for `ps_data->objfile == this->objfile`, because we know
the objfile is the sole JITer in this program space. Replace these two
conditions with assertions.
A pre-condition for calling the jit_read_descriptor function (which is
respected in the two call sites) is that the objfile `jiter` _is_ a
JITer - it already has a jiter_objfile_data attached to it. When a
jiter_objfile_data exists, its `descriptor` field is necessarily set:
had the descriptor symbol not been found, jit_breakpoint_re_set_internal
would not have created the jiter_objfile_data. Remove the check and
early return in jit_read_descriptor. Access objfile's `jiter_data` field
directly instead of calling `get_jiter_objfile_data` (which creates the
jiter_objfile_data if it doesn't exist yet) and assert that the result
is not nullptr.
Finally, `jit_event_handler` is always passed a JITer objfile. So, add
an assertion to ensure that.
gdb/ChangeLog:
2020-MM-DD Simon Marchi <simon.marchi@polymtl.ca>
* jit.c (jiter_objfile_data::~jiter_objfile_data): Remove some
checks.
(jit_read_descriptor): Remove NULL check.
(jit_event_handler): Add an assertion.
---
gdb/jit.c | 33 ++++++++++++++++-----------------
1 file changed, 16 insertions(+), 17 deletions(-)
diff --git a/gdb/jit.c b/gdb/jit.c
index 218871ed745..e5b6aa707ec 100644
--- a/gdb/jit.c
+++ b/gdb/jit.c
@@ -267,20 +267,17 @@ static program_space_key<jit_program_space_data> jit_program_space_key;
jiter_objfile_data::~jiter_objfile_data ()
{
- /* Free the data allocated in the jit_program_space_data slot. */
- if (this->register_code != NULL)
- {
- struct jit_program_space_data *ps_data;
+ jit_program_space_data *ps_data
+ = jit_program_space_key.get (this->objfile->pspace);
- ps_data = jit_program_space_key.get (this->objfile->pspace);
- if (ps_data != NULL && ps_data->objfile == this->objfile)
- {
- ps_data->objfile = NULL;
- if (ps_data->jit_breakpoint != NULL)
- delete_breakpoint (ps_data->jit_breakpoint);
- ps_data->cached_code_address = 0;
- }
- }
+ gdb_assert (ps_data != nullptr);
+ gdb_assert (ps_data->objfile == this->objfile);
+
+ ps_data->objfile = NULL;
+ if (ps_data->jit_breakpoint != NULL)
+ delete_breakpoint (ps_data->jit_breakpoint);
+
+ ps_data->cached_code_address = 0;
}
/* Fetch the jiter_objfile_data associated with OBJF. If no data exists
@@ -336,10 +333,8 @@ jit_read_descriptor (gdbarch *gdbarch,
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
gdb_assert (jiter != nullptr);
- jiter_objfile_data *objf_data = get_jiter_objfile_data (jiter);
-
- if (objf_data->descriptor == NULL)
- return false;
+ jiter_objfile_data *objf_data = jiter->jiter_data.get ();
+ gdb_assert (objf_data != nullptr);
if (jit_debug)
fprintf_unfiltered (gdb_stdlog,
@@ -1322,6 +1317,10 @@ jit_event_handler (gdbarch *gdbarch, objfile *jiter)
CORE_ADDR entry_addr;
struct objfile *objf;
+ /* If we get a JIT breakpoint event for this objfile, it is necessarily a
+ JITer. */
+ gdb_assert (jiter->jiter_data != nullptr);
+
/* Read the descriptor from remote memory. */
if (!jit_read_descriptor (gdbarch, &descriptor, jiter))
return;
--
2.17.1
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