src/etc/lldb_rust_formatters.py

   1 # Copyright 2014 The Rust Project Developers. See the COPYRIGHT
   2 # file at the top-level directory of this distribution and at
   3 # http://rust-lang.org/COPYRIGHT.
   4 #
   5 # Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 # http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 # <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 # option. This file may not be copied, modified, or distributed
   9 # except according to those terms.
  10
  11 import lldb
  12 import re
  13 import debugger_pretty_printers_common as rustpp
  14
  15 #===============================================================================
  16 # LLDB Pretty Printing Module for Rust
  17 #===============================================================================
  18
  19 class LldbType(rustpp.Type):
  20
  21     def __init__(self, ty):
  22         super(LldbType, self).__init__()
  23         self.ty = ty
  24         self.fields = None
  25
  26     def get_unqualified_type_name(self):
  27         qualified_name = self.ty.GetName()
  28
  29         if qualified_name is None:
  30             return qualified_name
  31
  32         return rustpp.extract_type_name(qualified_name).replace("&'static ", "&")
  33
  34     def get_dwarf_type_kind(self):
  35         type_class = self.ty.GetTypeClass()
  36
  37         if type_class == lldb.eTypeClassStruct:
  38             return rustpp.DWARF_TYPE_CODE_STRUCT
  39
  40         if type_class == lldb.eTypeClassUnion:
  41             return rustpp.DWARF_TYPE_CODE_UNION
  42
  43         if type_class == lldb.eTypeClassPointer:
  44             return rustpp.DWARF_TYPE_CODE_PTR
  45
  46         if type_class == lldb.eTypeClassArray:
  47             return rustpp.DWARF_TYPE_CODE_ARRAY
  48
  49         if type_class == lldb.eTypeClassEnumeration:
  50             return rustpp.DWARF_TYPE_CODE_ENUM
  51
  52         return None
  53
  54     def get_fields(self):
  55         assert ((self.get_dwarf_type_kind() == rustpp.DWARF_TYPE_CODE_STRUCT) or
  56                 (self.get_dwarf_type_kind() == rustpp.DWARF_TYPE_CODE_UNION))
  57         if self.fields is None:
  58             self.fields = list(self.ty.fields)
  59         return self.fields
  60
  61     def get_wrapped_value(self):
  62         return self.ty
  63
  64
  65 class LldbValue(rustpp.Value):
  66     def __init__(self, lldb_val):
  67         ty = lldb_val.type
  68         wty = LldbType(ty)
  69         super(LldbValue, self).__init__(wty)
  70         self.lldb_val = lldb_val
  71         self.children = {}
  72
  73     def get_child_at_index(self, index):
  74         child = self.children.get(index)
  75         if child is None:
  76             lldb_field = self.lldb_val.GetChildAtIndex(index)
  77             child = LldbValue(lldb_field)
  78             self.children[index] = child
  79         return child
  80
  81     def as_integer(self):
  82         return self.lldb_val.GetValueAsUnsigned()
  83
  84     def get_wrapped_value(self):
  85         return self.lldb_val
  86
  87
  88 def print_val(lldb_val, internal_dict):
  89     val = LldbValue(lldb_val)
  90     type_kind = val.type.get_type_kind()
  91
  92     if (type_kind == rustpp.TYPE_KIND_REGULAR_STRUCT or
  93         type_kind == rustpp.TYPE_KIND_REGULAR_UNION or
  94         type_kind == rustpp.TYPE_KIND_EMPTY):
  95         return print_struct_val(val,
  96                                 internal_dict,
  97                                 omit_first_field = False,
  98                                 omit_type_name = False,
  99                                 is_tuple_like = False)
 100
 101     if type_kind == rustpp.TYPE_KIND_STRUCT_VARIANT:
 102         return print_struct_val(val,
 103                                 internal_dict,
 104                                 omit_first_field = True,
 105                                 omit_type_name = False,
 106                                 is_tuple_like = False)
 107
 108     if type_kind == rustpp.TYPE_KIND_SLICE:
 109         return print_vec_slice_val(val, internal_dict)
 110
 111     if type_kind == rustpp.TYPE_KIND_STR_SLICE:
 112         return print_str_slice_val(val, internal_dict)
 113
 114     if type_kind == rustpp.TYPE_KIND_STD_VEC:
 115         return print_std_vec_val(val, internal_dict)
 116
 117     if type_kind == rustpp.TYPE_KIND_STD_STRING:
 118         return print_std_string_val(val, internal_dict)
 119
 120     if type_kind == rustpp.TYPE_KIND_TUPLE:
 121         return print_struct_val(val,
 122                                 internal_dict,
 123                                 omit_first_field = False,
 124                                 omit_type_name = True,
 125                                 is_tuple_like = True)
 126
 127     if type_kind == rustpp.TYPE_KIND_TUPLE_STRUCT:
 128         return print_struct_val(val,
 129                                 internal_dict,
 130                                 omit_first_field = False,
 131                                 omit_type_name = False,
 132                                 is_tuple_like = True)
 133
 134     if type_kind == rustpp.TYPE_KIND_CSTYLE_VARIANT:
 135         return val.type.get_unqualified_type_name()
 136
 137     if type_kind == rustpp.TYPE_KIND_TUPLE_VARIANT:
 138         return print_struct_val(val,
 139                                 internal_dict,
 140                                 omit_first_field = True,
 141                                 omit_type_name = False,
 142                                 is_tuple_like = True)
 143
 144     if type_kind == rustpp.TYPE_KIND_SINGLETON_ENUM:
 145         return print_val(lldb_val.GetChildAtIndex(0), internal_dict)
 146
 147     if type_kind == rustpp.TYPE_KIND_PTR:
 148         return print_pointer_val(val, internal_dict)
 149
 150     if type_kind == rustpp.TYPE_KIND_FIXED_SIZE_VEC:
 151         return print_fixed_size_vec_val(val, internal_dict)
 152
 153     if type_kind == rustpp.TYPE_KIND_REGULAR_ENUM:
 154         # This is a regular enum, extract the discriminant
 155         discriminant_val = rustpp.get_discriminant_value_as_integer(val)
 156         return print_val(lldb_val.GetChildAtIndex(discriminant_val), internal_dict)
 157
 158     if type_kind == rustpp.TYPE_KIND_COMPRESSED_ENUM:
 159         encoded_enum_info = rustpp.EncodedEnumInfo(val)
 160         if encoded_enum_info.is_null_variant():
 161             return encoded_enum_info.get_null_variant_name()
 162
 163         non_null_val = encoded_enum_info.get_non_null_variant_val()
 164         return print_val(non_null_val.get_wrapped_value(), internal_dict)
 165
 166     # No pretty printer has been found
 167     return lldb_val.GetValue()
 168
 169
 170 #=--------------------------------------------------------------------------------------------------
 171 # Type-Specialized Printing Functions
 172 #=--------------------------------------------------------------------------------------------------
 173
 174 def print_struct_val(val, internal_dict, omit_first_field, omit_type_name, is_tuple_like):
 175     """
 176     Prints a struct, tuple, or tuple struct value with Rust syntax.
 177     Ignores any fields before field_start_index.
 178     """
 179     assert (val.type.get_dwarf_type_kind() == rustpp.DWARF_TYPE_CODE_STRUCT or
 180             val.type.get_dwarf_type_kind() == rustpp.DWARF_TYPE_CODE_UNION)
 181
 182     if omit_type_name:
 183         type_name = ""
 184     else:
 185         type_name = val.type.get_unqualified_type_name()
 186
 187     if is_tuple_like:
 188         template = "%(type_name)s(%(body)s)"
 189         separator = ", "
 190     else:
 191         template = "%(type_name)s {\n%(body)s\n}"
 192         separator = ", \n"
 193
 194     fields = val.type.get_fields()
 195
 196     def render_child(child_index):
 197         this = ""
 198         if not is_tuple_like:
 199             field_name = fields[child_index].name
 200             this += field_name + ": "
 201
 202         field_val = val.get_child_at_index(child_index)
 203
 204         if not field_val.get_wrapped_value().IsValid():
 205             field = fields[child_index]
 206             # LLDB is not good at handling zero-sized values, so we have to help
 207             # it a little
 208             if field.GetType().GetByteSize() == 0:
 209                 return this + rustpp.extract_type_name(field.GetType().GetName())
 210             else:
 211                 return this + "<invalid value>"
 212
 213         return this + print_val(field_val.get_wrapped_value(), internal_dict)
 214
 215     if omit_first_field:
 216         field_start_index = 1
 217     else:
 218         field_start_index = 0
 219
 220     body = separator.join([render_child(idx) for idx in range(field_start_index, len(fields))])
 221
 222     return template % {"type_name": type_name,
 223                        "body": body}
 224
 225 def print_pointer_val(val, internal_dict):
 226     """Prints a pointer value with Rust syntax"""
 227     assert val.type.get_dwarf_type_kind() == rustpp.DWARF_TYPE_CODE_PTR
 228     sigil = "&"
 229     type_name = val.type.get_unqualified_type_name()
 230     if type_name and type_name[0:1] in ["&", "*"]:
 231         sigil = type_name[0:1]
 232
 233     return sigil + hex(val.as_integer())
 234
 235
 236 def print_fixed_size_vec_val(val, internal_dict):
 237     assert val.type.get_dwarf_type_kind() == rustpp.DWARF_TYPE_CODE_ARRAY
 238     lldb_val = val.get_wrapped_value()
 239
 240     output = "["
 241
 242     for i in range(lldb_val.num_children):
 243         output += print_val(lldb_val.GetChildAtIndex(i), internal_dict)
 244         if i != lldb_val.num_children - 1:
 245             output += ", "
 246
 247     output += "]"
 248     return output
 249
 250
 251 def print_vec_slice_val(val, internal_dict):
 252     (length, data_ptr) = rustpp.extract_length_and_ptr_from_slice(val)
 253     return "&[%s]" % print_array_of_values(val.get_wrapped_value().GetName(),
 254                                            data_ptr,
 255                                            length,
 256                                            internal_dict)
 257
 258
 259 def print_std_vec_val(val, internal_dict):
 260     (length, data_ptr, cap) = rustpp.extract_length_ptr_and_cap_from_std_vec(val)
 261     return "vec![%s]" % print_array_of_values(val.get_wrapped_value().GetName(),
 262                                               data_ptr,
 263                                               length,
 264                                               internal_dict)
 265
 266 def print_str_slice_val(val, internal_dict):
 267     (length, data_ptr) = rustpp.extract_length_and_ptr_from_slice(val)
 268     return read_utf8_string(data_ptr, length)
 269
 270 def print_std_string_val(val, internal_dict):
 271     vec = val.get_child_at_index(0)
 272     (length, data_ptr, cap) = rustpp.extract_length_ptr_and_cap_from_std_vec(vec)
 273     return read_utf8_string(data_ptr, length)
 274
 275 #=--------------------------------------------------------------------------------------------------
 276 # Helper Functions
 277 #=--------------------------------------------------------------------------------------------------
 278
 279 def print_array_of_values(array_name, data_ptr_val, length, internal_dict):
 280     """Prints a contiguous memory range, interpreting it as values of the
 281        pointee-type of data_ptr_val."""
 282
 283     data_ptr_type = data_ptr_val.type
 284     assert data_ptr_type.get_dwarf_type_kind() == rustpp.DWARF_TYPE_CODE_PTR
 285
 286     element_type = data_ptr_type.get_wrapped_value().GetPointeeType()
 287     element_type_size = element_type.GetByteSize()
 288
 289     start_address = data_ptr_val.as_integer()
 290     raw_value = data_ptr_val.get_wrapped_value()
 291
 292     def render_element(i):
 293         address = start_address + i * element_type_size
 294         element_val = raw_value.CreateValueFromAddress(array_name + ("[%s]" % i),
 295                                                        address,
 296                                                        element_type)
 297         return print_val(element_val, internal_dict)
 298
 299     return ', '.join([render_element(i) for i in range(length)])
 300
 301
 302 def read_utf8_string(ptr_val, byte_count):
 303     error = lldb.SBError()
 304     process = ptr_val.get_wrapped_value().GetProcess()
 305     data = process.ReadMemory(ptr_val.as_integer(), byte_count, error)
 306     if error.Success():
 307         return '"%s"' % data.decode(encoding='UTF-8')
 308     else:
 309         return '<error: %s>' % error.GetCString()