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[gdb/python] Fix gdb.python/py-disasm.exp on arm-linux

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After fixing test-case gdb.python/py-disasm.exp to recognize the arm nop:
...
	nop	{0}
...
we run into:
...
disassemble test^M
Dump of assembler code for function test:^M
   0x004004d8 <+0>:     push    {r11}           @ (str r11, [sp, #-4]!)^M
   0x004004dc <+4>:     add     r11, sp, #0^M
   0x004004e0 <+8>:     nop     {0}^M
=> 0x004004e4 <+12>:    Python Exception <class 'ValueError'>: Buffer \
  returned from read_memory is sized 0 instead of the expected 4^M
^M
unknown disassembler error (error = -1)^M
(gdb) FAIL: $exp: global_disassembler=ShowInfoRepr: disassemble test
...

This is caused by this code in gdbpy_disassembler::read_memory_func:
...
  gdbpy_ref<> result_obj (PyObject_CallMethod ((PyObject *) obj,
                                              "read_memory",
                                              "KL", len, offset));
...
where len has type "unsigned int", while "K" means "unsigned long long" [1].

Fix this by using "I" instead, meaning "unsigned int".

Also, offset has type LONGEST, which is typedef'ed to int64_t, while "L" means
"long long".

Fix this by using type gdb_py_longest for offset, in combination with format
character "GDB_PY_LL_ARG".  Likewise in disasmpy_info_read_memory.

Tested on arm-linux.

Reviewed-By: Alexandra Petlanova Hajkova <ahajkova@redhat.com>
Approved-By: Tom Tromey <tom@tromey.com>

PR python/31845
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31845

[1] https://docs.python.org/3/c-api/arg.html

(cherry picked from commit 4cd214dce4)
This commit is contained in:
Tom de Vries
2024-06-20 15:54:16 +02:00
parent 9c6d76c0d7
commit 1aa3b72f07
3 changed files with 9 additions and 7 deletions
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12
gdb/python/py-disasm.c
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@@ -667,12 +667,13 @@ disasmpy_info_read_memory (PyObject *self, PyObject *args, PyObject *kw)
disasm_info_object *obj = (disasm_info_object *) self;
DISASMPY_DISASM_INFO_REQUIRE_VALID (obj);
LONGEST length, offset = 0;
gdb_py_longest length, offset = 0;
gdb::unique_xmalloc_ptr<gdb_byte> buffer;
static const char *keywords[] = { "length", "offset", nullptr };
if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "L|L", keywords,
&length, &offset))
if (!gdb_PyArg_ParseTupleAndKeywords (args, kw,
GDB_PY_LL_ARG "|" GDB_PY_LL_ARG,
keywords, &length, &offset))
return nullptr;
/* The apparent address from which we are reading memory. Note that in
@@ -849,13 +850,14 @@ gdbpy_disassembler::read_memory_func (bfd_vma memaddr, gdb_byte *buff,
/* The DisassembleInfo.read_memory method expects an offset from the
address stored within the DisassembleInfo object; calculate that
offset here. */
LONGEST offset = (LONGEST) memaddr - (LONGEST) obj->address;
gdb_py_longest offset
= (gdb_py_longest) memaddr - (gdb_py_longest) obj->address;
/* Now call the DisassembleInfo.read_memory method. This might have been
overridden by the user. */
gdbpy_ref<> result_obj (PyObject_CallMethod ((PyObject *) obj,
"read_memory",
"KL", len, offset));
"I" GDB_PY_LL_ARG, len, offset));
/* Handle any exceptions. */
if (result_obj == nullptr)