6fd87d5d33
The synthetic children providers now use the new (safer) APIs to get the values of objects As a side effect, fixed an issue in ValueObject where ResolveValue() was not always updating the value before reading it llvm-svn: 136861
239 lines
7.9 KiB
Python
239 lines
7.9 KiB
Python
# synthetic children provider for CFString
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# (and related NSString class)
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import lldb
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class CFStringSynthProvider:
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def __init__(self,valobj,dict):
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self.valobj = valobj;
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self.update()
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# children other than "content" are for debugging only and must not be used in production code
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def num_children(self):
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if self.invalid:
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return 0;
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return 6;
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def read_unicode(self, pointer):
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process = self.valobj.GetTarget().GetProcess()
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error = lldb.SBError()
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pystr = u''
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# cannot do the read at once because the length value has
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# a weird encoding. better play it safe here
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while True:
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content = process.ReadMemory(pointer, 2, error)
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new_bytes = bytearray(content)
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b0 = new_bytes[0]
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b1 = new_bytes[1]
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pointer = pointer + 2
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if b0 == 0 and b1 == 0:
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break
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# rearrange bytes depending on endianness
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# (do we really need this or is Cocoa going to
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# use Windows-compatible little-endian even
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# if the target is big endian?)
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if self.is_little:
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value = b1 * 256 + b0
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else:
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value = b0 * 256 + b1
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pystr = pystr + unichr(value)
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return pystr
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# handle the special case strings
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# only use the custom code for the tested LP64 case
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def handle_special(self):
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if self.lp64 == False:
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# for 32bit targets, use safe ObjC code
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return self.handle_unicode_string_safe()
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offset = 12
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pointer = self.valobj.GetValueAsUnsigned(0) + offset
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pystr = self.read_unicode(pointer)
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return self.valobj.CreateValueFromExpression("content",
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"(char*)\"" + pystr.encode('utf-8') + "\"")
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# last resort call, use ObjC code to read; the final aim is to
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# be able to strip this call away entirely and only do the read
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# ourselves
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def handle_unicode_string_safe(self):
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return self.valobj.CreateValueFromExpression("content",
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"(char*)\"" + self.valobj.GetObjectDescription() + "\"");
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def handle_unicode_string(self):
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# step 1: find offset
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if self.inline:
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pointer = self.valobj.GetValueAsUnsigned(0) + self.size_of_cfruntime_base();
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if self.explicit == False:
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# untested, use the safe code path
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return self.handle_unicode_string_safe();
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else:
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# not sure why 8 bytes are skipped here
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# (lldb) mem read -c 50 0x00000001001154f0
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# 0x1001154f0: 98 1a 85 71 ff 7f 00 00 90 07 00 00 01 00 00 00 ...q?...........
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# 0x100115500: 03 00 00 00 00 00 00 00 *c3 03 78 00 78 00 00 00 ........?.x.x...
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# 0x100115510: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
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# 0x100115520: 00 00 ..
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# content begins at * (i.e. 8 bytes into variants, skipping void* buffer in
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# __notInlineImmutable1 entirely, while the length byte is correctly located
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# for an inline string)
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pointer = pointer + 8;
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else:
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pointer = self.valobj.GetValueAsUnsigned(0) + self.size_of_cfruntime_base();
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# read 8 bytes here and make an address out of them
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vopointer = self.valobj.CreateChildAtOffset("dummy",
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pointer,self.valobj.GetType().GetBasicType(lldb.eBasicTypeChar).GetPointerType());
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pointer = vopointer.GetValueAsUnsigned(0)
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# step 2: read Unicode data at pointer
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pystr = self.read_unicode(pointer)
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# step 3: return it
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return self.valobj.CreateValueFromExpression("content",
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"(char*)\"" + pystr.encode('utf-8') + "\"")
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# we read at "the right place" into the __CFString object instead of running code
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# we are replicating the functionality of __CFStrContents in CFString.c here
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def handle_UTF8_inline(self):
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offset = int(self.valobj.GetValue(), 0) + self.size_of_cfruntime_base();
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if self.explicit == False:
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offset = offset + 1;
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return self.valobj.CreateValueFromAddress("content",
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offset, self.valobj.GetType().GetBasicType(lldb.eBasicTypeChar));
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def handle_UTF8_not_inline(self):
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offset = self.size_of_cfruntime_base();
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return self.valobj.CreateChildAtOffset("content",
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offset,self.valobj.GetType().GetBasicType(lldb.eBasicTypeChar).GetPointerType());
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def get_child_at_index(self,index):
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if index == 0:
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return self.valobj.CreateValueFromExpression("mutable",
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str(int(self.mutable)));
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if index == 1:
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return self.valobj.CreateValueFromExpression("inline",
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str(int(self.inline)));
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if index == 2:
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return self.valobj.CreateValueFromExpression("explicit",
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str(int(self.explicit)));
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if index == 3:
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return self.valobj.CreateValueFromExpression("unicode",
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str(int(self.unicode)));
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if index == 4:
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return self.valobj.CreateValueFromExpression("special",
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str(int(self.special)));
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if index == 5:
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if self.unicode == True:
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return self.handle_unicode_string();
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elif self.special == True:
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return self.handle_special();
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elif self.inline == True:
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return self.handle_UTF8_inline();
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else:
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return self.handle_UTF8_not_inline();
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def get_child_index(self,name):
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if name == "content":
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return self.num_children() - 1;
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if name == "mutable":
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return 0;
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if name == "inline":
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return 1;
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if name == "explicit":
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return 2;
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if name == "unicode":
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return 3;
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if name == "special":
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return 4;
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def is_64bit(self):
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return self.valobj.GetTarget().GetProcess().GetAddressByteSize() == 8
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def is_little_endian(self):
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return self.valobj.GetTarget().GetProcess().GetByteOrder() == lldb.eByteOrderLittle
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# CFRuntimeBase is defined as having an additional
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# 4 bytes (padding?) on LP64 architectures
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# to get its size we add up sizeof(pointer)+4
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# and then add 4 more bytes if we are on a 64bit system
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def size_of_cfruntime_base(self):
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if self.lp64 == True:
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return 8+4+4;
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else:
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return 4+4;
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# the info bits are part of the CFRuntimeBase structure
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# to get at them we have to skip a uintptr_t and then get
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# at the least-significant byte of a 4 byte array. If we are
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# on big-endian this means going to byte 3, if we are on
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# little endian (OSX & iOS), this means reading byte 0
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def offset_of_info_bits(self):
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if self.lp64 == True:
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offset = 8;
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else:
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offset = 4;
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if self.is_little == False:
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offset = offset + 3;
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return offset;
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def read_info_bits(self):
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cfinfo = self.valobj.CreateChildAtOffset("cfinfo",
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self.offset_of_info_bits(),
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self.valobj.GetType().GetBasicType(lldb.eBasicTypeChar));
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cfinfo.SetFormat(11)
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info = cfinfo.GetValue();
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if info != None:
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self.invalid = False;
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return int(info,0);
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else:
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self.invalid = True;
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return None;
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# calculating internal flag bits of the CFString object
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# this stuff is defined and discussed in CFString.c
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def is_mutable(self):
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return (self.info_bits & 1) == 1;
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def is_inline(self):
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return (self.info_bits & 0x60) == 0;
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# this flag's name is ambiguous, it turns out
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# we must skip a length byte to get at the data
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# when this flag is False
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def has_explicit_length(self):
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return (self.info_bits & (1 | 4)) != 4;
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# probably a subclass of NSString. obtained this from [str pathExtension]
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# here info_bits = 0 and Unicode data at the start of the padding word
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# in the long run using the isa value might be safer as a way to identify this
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# instead of reading the info_bits
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def is_special_case(self):
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return self.info_bits == 0;
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def is_unicode(self):
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return (self.info_bits & 0x10) == 0x10;
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# preparing ourselves to read into memory
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# by adjusting architecture-specific info
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def adjust_for_architecture(self):
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self.lp64 = self.is_64bit();
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self.is_little = self.is_little_endian();
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# reading info bits out of the CFString and computing
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# useful values to get at the real data
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def compute_flags(self):
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self.info_bits = self.read_info_bits();
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if self.info_bits == None:
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return;
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self.mutable = self.is_mutable();
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self.inline = self.is_inline();
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self.explicit = self.has_explicit_length();
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self.unicode = self.is_unicode();
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self.special = self.is_special_case();
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def update(self):
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self.adjust_for_architecture();
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self.compute_flags();
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def CFString_SummaryProvider (valobj,dict):
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provider = CFStringSynthProvider(valobj,dict);
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if provider.invalid == False:
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return provider.get_child_at_index(provider.get_child_index("content")).GetSummary();
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return ''
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