From f7306dac19c502232f766c3881313857915f330d Mon Sep 17 00:00:00 2001 From: Andrew Burgess Date: Tue, 7 Jul 2020 15:00:30 +0100 Subject: [PATCH] gdb/python: Reuse gdb.RegisterDescriptor objects where possible Instead of having the gdb.RegisterDescriptorIterator creating new gdb.RegisterDescriptor objects for each regnum, instead cache gdb.RegisterDescriptor objects on the gdbarch object and reuse these. This means that for every gdbarch/regnum pair there is a single unique gdb.RegisterDescriptor, this feels like a neater implementation than the existing one. It is possible for a user to see (in Python code) that the descriptors are now identical, but as the descriptors are read-only this should make no real difference. There should be no other user visible changes. gdb/ChangeLog: * python/py-registers.c (gdbpy_register_object_data): New static global. (gdbpy_register_object_data_init): New function. (gdbpy_new_register_descriptor): Renamed to... (gdbpy_get_register_descriptor): ...this, and update to reuse existing register descriptors where possible. (gdbpy_register_descriptor_iter_next): Update. (gdbpy_initialize_registers): Register new gdbarch data. gdb/testsuite/ChangeLog: * gdb.python/py-arch-reg-names.exp: Additional tests. --- gdb/ChangeLog | 11 ++++ gdb/python/py-registers.c | 61 +++++++++++++++---- gdb/testsuite/ChangeLog | 4 ++ .../gdb.python/py-arch-reg-names.exp | 19 ++++++ 4 files changed, 82 insertions(+), 13 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index b15a3a4e25f..e2d2e15b653 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,14 @@ +2020-07-21 Andrew Burgess + + * python/py-registers.c (gdbpy_register_object_data): New static + global. + (gdbpy_register_object_data_init): New function. + (gdbpy_new_register_descriptor): Renamed to... + (gdbpy_get_register_descriptor): ...this, and update to reuse + existing register descriptors where possible. + (gdbpy_register_descriptor_iter_next): Update. + (gdbpy_initialize_registers): Register new gdbarch data. + 2020-07-21 Simon Marchi * linux-nat.c (stopped_pids): Make static. diff --git a/gdb/python/py-registers.c b/gdb/python/py-registers.c index db0fe37eecb..8e22a919d87 100644 --- a/gdb/python/py-registers.c +++ b/gdb/python/py-registers.c @@ -24,6 +24,9 @@ #include "reggroups.h" #include "python-internal.h" +/* Token to access per-gdbarch data related to register descriptors. */ +static struct gdbarch_data *gdbpy_register_object_data = NULL; + /* Structure for iterator over register descriptors. */ typedef struct { PyObject_HEAD @@ -81,6 +84,17 @@ typedef struct { extern PyTypeObject reggroup_object_type CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("reggroup_object"); +/* Associates a vector of gdb.RegisterDescriptor objects with GDBARCH as + gdbarch_data via the gdbarch post init registration mechanism + (gdbarch_data_register_post_init). */ + +static void * +gdbpy_register_object_data_init (struct gdbarch *gdbarch) +{ + std::vector> *vec = new (std::vector>); + return (void *) vec; +} + /* Create a new gdb.RegisterGroup object wrapping REGGROUP. */ static PyObject * @@ -117,20 +131,38 @@ gdbpy_reggroup_name (PyObject *self, void *closure) return gdbpy_reggroup_to_string (self); } -/* Create an return a new gdb.RegisterDescriptor object. */ -static PyObject * -gdbpy_new_register_descriptor (struct gdbarch *gdbarch, +/* Return a gdb.RegisterDescriptor object for REGNUM from GDBARCH. For + each REGNUM (in GDBARCH) only one descriptor is ever created, which is + then cached on the GDBARCH. */ + +static gdbpy_ref<> +gdbpy_get_register_descriptor (struct gdbarch *gdbarch, int regnum) { - /* Create a new object and fill in its details. */ - register_descriptor_object *reg - = PyObject_New (register_descriptor_object, - ®ister_descriptor_object_type); - if (reg == NULL) - return NULL; - reg->regnum = regnum; - reg->gdbarch = gdbarch; - return (PyObject *) reg; + auto vec = (std::vector> *) gdbarch_data + (gdbarch, gdbpy_register_object_data); + + /* Ensure that we have enough entries in the vector. */ + if (vec->size () <= regnum) + vec->resize ((regnum + 1), nullptr); + + /* If we don't already have a descriptor for REGNUM in GDBARCH then + create one now. */ + if (vec->at (regnum) == nullptr) + { + gdbpy_ref reg + (PyObject_New (register_descriptor_object, + ®ister_descriptor_object_type)); + if (reg == NULL) + return NULL; + reg->regnum = regnum; + reg->gdbarch = gdbarch; + vec->at (regnum) = gdbpy_ref<> ((PyObject *) reg.release ()); + } + + /* Grab the register descriptor from the vector, the reference count is + automatically incremented thanks to gdbpy_ref. */ + return vec->at (regnum); } /* Convert the register descriptor to a string. */ @@ -281,7 +313,7 @@ gdbpy_register_descriptor_iter_next (PyObject *self) iter_obj->regnum++; if (name != nullptr && *name != '\0') - return gdbpy_new_register_descriptor (gdbarch, regnum); + return gdbpy_get_register_descriptor (gdbarch, regnum).release (); } while (true); } @@ -291,6 +323,9 @@ gdbpy_register_descriptor_iter_next (PyObject *self) int gdbpy_initialize_registers () { + gdbpy_register_object_data + = gdbarch_data_register_post_init (gdbpy_register_object_data_init); + register_descriptor_object_type.tp_new = PyType_GenericNew; if (PyType_Ready (®ister_descriptor_object_type) < 0) return -1; diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 804df0264b5..6b13e928497 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2020-07-21 Andrew Burgess + + * gdb.python/py-arch-reg-names.exp: Additional tests. + 2020-07-21 Tom de Vries * gdb.reverse/solib-precsave.exp: Handle additional "recommended diff --git a/gdb/testsuite/gdb.python/py-arch-reg-names.exp b/gdb/testsuite/gdb.python/py-arch-reg-names.exp index 14bc0a822a4..8dd34ef5fd2 100644 --- a/gdb/testsuite/gdb.python/py-arch-reg-names.exp +++ b/gdb/testsuite/gdb.python/py-arch-reg-names.exp @@ -85,3 +85,22 @@ for { set i 0 } { $i < [llength $regs] } { incr i } { } } gdb_assert { $found_non_match == 0 } "all registers match" + +# Check that we get the same register descriptors from two different +# iterators. +gdb_py_test_silent_cmd \ + "python iter1 = arch.registers ()" \ + "get first all register iterator" 0 +gdb_py_test_silent_cmd \ + "python iter2 = arch.registers ()" \ + "get second all register iterator" 0 +gdb_py_test_silent_cmd \ + [multi_line_input \ + "python" \ + "for r1, r2 in zip(iter1, iter2):" \ + " if (r1.name != r2.name):"\ + " raise gdb.GdbError (\"miss-matched names\")" \ + " if (r1 != r2):" \ + " raise gdb.GdbError (\"miss-matched objects\")" \ + "\004" ] \ + "check names and objects match" 1 -- 2.30.2