如何使用gdb.pretty_pointers打印struct的指针成员？

Question

我有一个这样的 C 结构：

typedef uint8_t matrix_size_t;
struct _matrix {
  /* data */
  uint8_t inited;
  matrix_size_t rows;
  matrix_size_t cols;
  ElemType* data;
};

我想用行和列格式打印 Matrix.data，这是我的 python 代码：

import gdb
import numpy as np
import logging


class McuMatrixPrinter:

    def __init__(self, variety, val):
        self.variety = variety
        self.inited = val["inited"]
        self.rows = int(val["rows"])
        self.cols = int(val["cols"])
        self.data = val["data"]
        self.type = self.data.type.unqualified().strip_typedefs()
        self.data = self.data.cast(self.type.pointer())
        logging.info(self.type)
        logging.info(type(self.data))

    def to_string(self):
        if int(self.inited) == 0:
            return "This matrix has not been inited!"
        mat = np.zeros((self.rows, self.cols), dtype=np.float64)
        for row in range(self.rows):
            for col in range(self.cols):
                offset = row * self.cols + col
                item = (self.data + offset).dereference()
                logging.info(type(item))
                mat[row, col] = float(item)
        return "Matrix::%s<%d,%d>\n%s\n" % (self.variety, self.rows, self.cols,
                                            self.data, mat)


def PrintMatrix(val):
    type = val.type
    if type.code == gdb.TYPE_CODE_REF:
        type = type.target()

    type = type.unqualified().strip_typedefs()
    typename = type.tag
    if typename == None:
        return None
    if typename.find("_matrix") != -1:
        return McuMatrixPrinter("Matrix", val)
    return None


def register_matrix_printers(obj):
    "Register eigen pretty-printers with objfile Obj"
    logging.basicConfig(
        level=logging.DEBUG, 
        filename='/tmp/gdbpy.log',
        filemode='a',
        format=
        '%(asctime)s - %(pathname)s[line:%(lineno)d] - %(levelname)s: %(message)s'
    )
    if obj == None:
        obj = gdb
    obj.pretty_printers.append(PrintMatrix)

然而，我得到了这个例外：

(gdb) p 向量 $1 = Python 异常 无法将值转换为浮点数。:

(gdb) p 向量 $2 = Python 异常 无法将值转换为浮点数。:

有解决方案可以解决我的问题吗？