1 \chapter{Data Representation}
2 \label{datarep:datarepresentation}
4 This section describes the binary representation of the
5 debugging information entry itself, of the attribute types
6 and of other fundamental elements described above.
9 \section{Vendor Extensibility}
10 \label{datarep:vendorextensibility}
12 To reserve a portion of the DWARF name space and ranges of
13 enumeration values for use for vendor specific extensions,
14 special labels are reserved for tag names, attribute names,
15 base type encodings, location operations, language names,
16 calling conventions and call frame instructions.
18 The labels denoting the beginning and end of the reserved
19 value range for vendor specific extensions consist of the
20 appropriate prefix (DW\-\_TAG, DW\-\_AT, DW\-\_END, DW\-\_ATE, DW\-\_OP,
21 DW\-\_LANG, DW\-\_LNE, DW\-\_CC or DW\-\_CFA respectively) followed by
22 \_lo\_user or \_hi\_user.
23 \textit{For example, for entry tags, the special
24 labels are \livetarg{chap:DWTAGlouser}{DW\-\_TAG\-\_lo\-\_user} and
25 \livetarg{chap:DWTAGhiuser}{DW\-\_TAG\-\_hi\-\_user}.}
27 range between prefix\_lo\_user and prefix\_hi\_user inclusive,
28 are reserved for vendor specific extensions. Vendors may
29 use values in this range without conflicting with current or
30 future system\dash defined values. All other values are reserved
31 for use by the system.
33 \textit{There may also be codes for vendor specific extensions
34 between the number of standard line number opcodes and
35 the first special line number opcode. However, since the
36 number of standard opcodes varies with the DWARF version,
37 the range for extensions is also version dependent. Thus,
38 \livetarg{chap:DWLNSlouser}{DW\-\_LNS\-\_lo\-\_user} and
39 \livetarg{chap:DWLNShiuser}{DW\-\_LNS\-\_hi\-\_user} symbols are not defined.}
41 Vendor defined tags, attributes, base type encodings, location
42 atoms, language names, line number actions, calling conventions
43 and call frame instructions, conventionally use the form
44 prefix\_vendor\_id\_name, where vendor\_id is some identifying
45 character sequence chosen so as to avoid conflicts with
48 To ensure that extensions added by one vendor may be safely
49 ignored by consumers that do not understand those extensions,
50 the following rules should be followed:
53 \item New attributes should be added in such a way that a
54 debugger may recognize the format of a new attribute value
55 without knowing the content of that attribute value.
57 \item The semantics of any new attributes should not alter
58 the semantics of previously existing attributes.
60 \item The semantics of any new tags should not conflict with
61 the semantics of previously existing tags.
63 \item Do not add any new forms of attribute value.
68 \section{Reserved Values}
69 \label{datarep:reservedvalues}
70 \subsection{Error Values}
71 \label{datarep:errorvalues}
73 As a convenience for consumers of DWARF information, the value
74 0 is reserved in the encodings for attribute names, attribute
75 forms, base type encodings, location operations, languages,
76 line number program opcodes, macro information entries and tag
77 names to represent an error condition or unknown value. DWARF
78 does not specify names for these reserved values, since they
79 do not represent valid encodings for the given type and should
80 not appear in DWARF debugging information.
83 \subsection{Initial Length Values}
84 \label{datarep:initiallengthvalues}
86 An initial length field is one of the length fields that occur
87 at the beginning of those DWARF sections that have a header
88 (.debug\_aranges, .debug\_info, .debug\_types, .debug\_line,
89 .debug\_pubnames, and .debug\_pubtypes) or the length field
90 that occurs at the beginning of the CIE and FDE structures
91 in the .debug\_frame section.
93 In an initial length field, the values 0xfffffff0 through
94 0xffffffff are reserved by DWARF to indicate some form of
95 extension relative to DWARF Version 2; such values must not
96 be interpreted as a length field. The use of one such value,
97 0xffffffff, is defined below
98 (see Section \refersec{datarep:32bitand64bitdwarfformats});
100 the other values is reserved for possible future extensions.
104 \section{Executable Objects and Shared Objects}
105 \label{datarep:executableobjectsandsharedobjects}
107 The relocated addresses in the debugging information for an
108 executable object are virtual addresses and the relocated
109 addresses in the debugging information for a shared object
110 are offsets relative to the start of the lowest region of
111 memory loaded from that shared object.
113 \textit{This requirement makes the debugging information for
114 shared objects position independent. Virtual addresses in a
115 shared object may be calculated by adding the offset to the
116 base address at which the object was attached. This offset
117 is available in the run\dash time linker’s data structures.}
121 \section{32-Bit and 64-Bit DWARF Formats}
122 \label{datarep:32bitand64bitdwarfformats}
124 There are two closely related file formats. In the 32\dash bit DWARF
125 format, all values that represent lengths of DWARF sections
126 and offsets relative to the beginning of DWARF sections are
127 represented using 32\dash bits. In the 64\dash bit DWARF format, all
128 values that represent lengths of DWARF sections and offsets
129 relative to the beginning of DWARF sections are represented
130 using 64\dash bits. A special convention applies to the initial
131 length field of certain DWARF sections, as well as the CIE and
132 FDE structures, so that the 32\dash bit and 64\dash bit DWARF formats
133 can coexist and be distinguished within a single linked object.
135 The differences between the 32\dash\ and 64\dash bit
137 detailed in the following:
140 \begin{enumerate}[1.]
142 \item In the 32\dash bit DWARF format, an initial length field
143 (see Section \refersec{datarep:initiallengthvalues})
144 is an unsigned 32\dash bit integer (which
145 must be less than 0xfffffff0); in the 64\dash bit DWARF format,
146 an initial length field is 96 bits in size, and has two parts:
148 \item The first 32\dash bits have the value 0xffffffff.
150 \item The following 64\dash bits contain the actual length
151 represented as an unsigned 64\dash bit integer.
154 \textit{This representation allows a DWARF consumer to dynamically
155 detect that a DWARF section contribution is using the 64\dash bit
156 format and to adapt its processing accordingly.}
158 \item Section offset and section length fields that occur
159 in the headers of DWARF sections (other than initial length
160 fields) are listed following. In the 32\dash bit DWARF format these
161 are 32\dash bit unsigned integer values; in the 64\dash bit DWARF format,
162 they are 64\dash bit unsigned integer values.
166 Section &Name & Role \\ \hline
167 .debug\_ranges & debug\_info\_offset & offset in .debug\_info \\
168 .debug\_frame/CIE & CIE\_id & CIE distinguished value \\
169 .debug\_frame/FDE & CIE\_pointer & offset in .debug\_frame \\
170 .debug\_info & debug\_abbrev\_offset & offset in .debug\_abbrev \\
171 .debug\_line & header\_length & length of header itself \\
172 .debug\_pubnames & debug\_info\_offset & offset in .debug\_info \\
173 & debug\_info\_length & length of .debug\_info \\
175 .debug\_pubtypes & debug\_info\_offset & offset in .debug\_info \\
176 & debug\_info\_length & length of .debug\_info \\
178 .debug\_types & debug\_abbrev\_offset & offset in .debug\_info \\
179 & type\_offset & offset in of .debug\_types \\
184 \textit{The CIE\_id field in a CIE structure must be 64 bits because
185 it overlays the CIE\_pointer in a FDE structure; this implicit
186 union must be accessed to distinguish whether a CIE or FDE is
187 present, consequently, these two fields must exactly overlay
188 each other (both offset and size).}
190 \item Within the body of the .debug\_info or .debug\_types
191 section, certain forms of attribute value depend on the choice
192 of DWARF format as follows. For the 32\dash bit DWARF format,
193 the value is a 32\dash bit unsigned integer; for the 64\dash bit DWARF
194 format, the value is a 64\dash bit unsigned integer.
197 Form & Role \\ \hline
198 \livelink{chap:DWFORMrefaddr}{DW\-\_FORM\-\_ref\-\_addr}& offset in .debug\_info \\
199 \livetarg{chap:DWFORMsecoffset}{DW\-\_FORM\-\_sec\-\_offset}& offset in a section other than .debug\_info or .debug\_str \\
200 \livelink{chap:DWFORMstrp}{DW\-\_FORM\-\_strp}&offset in .debug\_str \\
201 \livelink{chap:DWOPcallref}{DW\-\_OP\-\_call\-\_ref}&offset in .debug\_info \\
205 \item Within the body of the .debug\_pubnames and
206 .debug\_pubtypes sections, the representation of the first field
207 of each tuple (which represents an offset in the .debug\_info
208 section) depends on the DWARF format as follows: in the
209 32\dash bit DWARF format, this field is a 32\dash bit unsigned integer;
210 in the 64\dash bit DWARF format, it is a 64\dash bit unsigned integer.
215 The 32\dash bit and 64\dash bit DWARF format conventions must not be
216 intermixed within a single compilation unit.
218 \textit{Attribute values and section header fields that represent
219 addresses in the target program are not affected by these
222 A DWARF consumer that supports the 64\dash bit DWARF format must
223 support executables in which some compilation units use the
224 32\dash bit format and others use the 64\dash bit format provided that
225 the combination links correctly (that is, provided that there
226 are no link\dash time errors due to truncation or overflow). (An
227 implementation is not required to guarantee detection and
228 reporting of all such errors.)
230 \textit{It is expected that DWARF producing compilers will not use
231 the 64\dash bit format by default. In most cases, the division of
232 even very large applications into a number of executable and
233 shared objects will suffice to assure that the DWARF sections
234 within each individual linked object are less than 4 GBytes
235 in size. However, for those cases where needed, the 64\dash bit
236 format allows the unusual case to be handled as well. Even
237 in this case, it is expected that only application supplied
238 objects will need to be compiled using the 64\dash bit format;
239 separate 32\dash bit format versions of system supplied shared
240 executable libraries can still be used.}
244 \section{Format of Debugging Information}
245 \label{datarep:formatofdebugginginformation}
247 For each compilation unit compiled with a DWARF producer,
248 a contribution is made to the .debug\_info section of
249 the object file. Each such contribution consists of a
250 compilation unit header
251 (see Section \refersec{datarep:compilationunitheader})
253 single \livelink{chap:DWTAGcompileunit}{DW\-\_TAG\-\_compile\-\_unit} or \livelink{chap:DWTAGpartialunit}{DW\-\_TAG\-\_partial\-\_unit} debugging
254 information entry, together with its children.
256 For each type defined in a compilation unit, a contribution may
257 be made to the .debug\_types section of the object file. Each
258 such contribution consists of a type unit header
259 (see Section \refersec{datarep:typeunitheader})
260 followed by a \livelink{chap:DWTAGtypeunit}{DW\-\_TAG\-\_type\-\_unit} entry, together with
263 Each debugging information entry begins with a code that
264 represents an entry in a separate abbreviations table. This
265 code is followed directly by a series of attribute values.
267 The appropriate entry in the abbreviations table guides the
268 interpretation of the information contained directly in the
269 .debug\_info or .debug\_types section.
271 Multiple debugging information entries may share the same
272 abbreviation table entry. Each compilation unit is associated
273 with a particular abbreviation table, but multiple compilation
274 units may share the same table.
275 \subsection{Unit Headers}
276 \label{datarep:unitheaders}
278 \subsubsection{Compilation Unit Header}
279 \label{datarep:compilationunitheader}
281 \begin{enumerate}[1.]
283 \item unit\_length (initial length) \\
284 A 4\dash byte or 12\dash byte unsigned integer representing the length
285 of the .debug\_info contribution for that compilation unit,
286 not including the length field itself. In the 32\dash bit DWARF
287 format, this is a 4\dash byte unsigned integer (which must be less
288 than 0xfffffff0); in the 64\dash bit DWARF format, this consists
289 of the 4\dash byte value 0xffffffff followed by an 8\dash byte unsigned
290 integer that gives the actual length
291 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
293 \item version (uhalf)
294 A 2\dash byte unsigned integer representing the version of the
295 DWARF information for the compilation unit
296 (see Appendix \refersec{app:dwarfsectionversionnumbersinformative}).
297 The value in this field is 4.
299 \item debug\_abbrev\_offset (section offset) \\
300 A 4\dash byte or 8\dash byte unsigned offset into the .debug\_abbrev
301 section. This offset associates the compilation unit with a
302 particular set of debugging information entry abbreviations. In
303 the 32\dash bit DWARF format, this is a 4\dash byte unsigned length;
304 in the 64\dash bit DWARF format, this is an 8\dash byte unsigned length
305 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
307 \item address\_size (ubyte) \\
308 A 1\dash byte unsigned integer representing the size in bytes of
309 an address on the target architecture. If the system uses
310 segmented addressing, this value represents the size of the
311 offset portion of an address.
318 \subsubsection{Type Unit Header}
319 \label{datarep:typeunitheader}
321 The header for the series of debugging information entries
322 contributing to the description of a type that has been
323 placed in its own type unit, within the .debug\_types section,
324 consists of the following information:
326 \begin{enumerate}[1.]
328 \item unit\_length (initial length) \\
329 A 4\dash byte or 12\dash byte unsigned integer representing the length
330 of the .debug\_types contribution for that compilation unit,
331 not including the length field itself. In the 32\dash bit DWARF
332 format, this is a 4\dash byte unsigned integer (which must be
333 less than 0xfffffff0); in the 64\dash bit DWARF format, this
334 consists of the 4\dash byte value 0xffffffff followed by an
335 8\dash byte unsigned integer that gives the actual length
336 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
338 \item version (uhalf)
339 A 2\dash byte unsigned integer representing the version of the
340 DWARF information for the compilation unit
341 (see Appendix \refersec{app:dwarfsectionversionnumbersinformative}).
342 The value in this field is 4.
344 \item debug\_abbrev\_offset (section offset) \\
345 A 4\dash byte or 8\dash byte unsigned offset into the .debug\_abbrev
346 section. This offset associates the compilation unit with a
347 particular set of debugging information entry abbreviations. In
348 the 32\dash bit DWARF format, this is a 4\dash byte unsigned length;
349 in the 64\dash bit DWARF format, this is an 8\dash byte unsigned length
350 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
352 \item address\_size (ubyte) \\
353 A 1\dash byte unsigned integer representing the size in bytes of
354 an address on the target architecture. If the system uses
355 segmented addressing, this value represents the size of the
356 offset portion of an address.
359 \item type\_signature (8\dash byte unsigned integer) \\
360 A 64\dash bit unique signature of the type described in this type
363 \textit{An attribute that refers(using \livelink{chap:DWFORMrefsig8}{DW\-\_FORM\-\_ref\-\_sig8}) to
364 the primary type contained in this type unit uses this value.}
367 \item type\_offset (section offset) \\
368 A 4\dash byte or 8\dash byte unsigned offset relative to the beginning
369 of the type unit header. This offset refers to the debugging
370 information entry that describes the type. Because the type
371 may be nested inside a namespace or other structures, and may
372 contain references to other types that have not been placed in
373 separate type units, it is not necessarily either the first or
374 the only entry in the type unit. In the 32\dash bit DWARF format,
375 this is a 4\dash byte unsigned length; in the 64\dash bit DWARF format,
376 this is an 8\dash byte unsigned length
377 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
381 \subsection{Debugging Information Entry}
382 \label{datarep:debugginginformationentry}
384 Each debugging information entry begins with an unsigned LEB128
385 number containing the abbreviation code for the entry. This
386 code represents an entry within the abbreviations table
387 associated with the compilation unit containing this entry. The
388 abbreviation code is followed by a series of attribute values.
390 On some architectures, there are alignment constraints on
391 section boundaries. To make it easier to pad debugging
392 information sections to satisfy such constraints, the
393 abbreviation code 0 is reserved. Debugging information entries
394 consisting of only the abbreviation code 0 are considered
397 \subsection{Abbreviations Tables}
398 \label{datarep:abbreviationstables}
400 The abbreviations tables for all compilation units
401 are contained in a separate object file section called
402 .debug\_abbrev. As mentioned before, multiple compilation
403 units may share the same abbreviations table.
405 The abbreviations table for a single compilation unit consists
406 of a series of abbreviation declarations. Each declaration
407 specifies the tag and attributes for a particular form of
408 debugging information entry. Each declaration begins with
409 an unsigned LEB128 number representing the abbreviation
410 code itself. It is this code that appears at the beginning
411 of a debugging information entry in the .debug\_info or
412 .debug\_types section. As described above, the abbreviation
413 code 0 is reserved for null debugging information entries. The
414 abbreviation code is followed by another unsigned LEB128
415 number that encodes the entry’s tag. The encodings for the
416 tag names are given in
417 Table \refersec{tab:tagencodings}.
419 Following the tag encoding is a 1\dash byte value that determines
420 whether a debugging information entry using this abbreviation
421 has child entries or not. If the value is
422 \livetarg{chap:DWCHILDRENyes}{DW\-\_CHILDREN\-\_yes},
423 the next physically succeeding entry of any debugging
424 information entry using this abbreviation is the first
425 child of that entry. If the 1\dash byte value following the
426 abbreviation’s tag encoding is
427 \livetarg{chap:DWCHILDRENno}{DW\-\_CHILDREN\-\_no}, the next
428 physically succeeding entry of any debugging information entry
429 using this abbreviation is a sibling of that entry. (Either
430 the first child or sibling entries may be null entries). The
431 encodings for the child determination byte are given in
432 Table \refersec{tab:childdeterminationencodings}
434 Section \refersec{chap:relationshipofdebugginginformationentries},
436 sibling entries is terminated by a null entry.)
438 Finally, the child encoding is followed by a series of
439 attribute specifications. Each attribute specification
440 consists of two parts. The first part is an unsigned LEB128
441 number representing the attribute’s name. The second part
442 is an unsigned LEB128 number representing the attribute’s
443 form. The series of attribute specifications ends with an
444 entry containing 0 for the name and 0 for the form.
447 \livetarg{chap:DWFORMindirect}{DW\-\_FORM\-\_indirect} is a special case. For
448 attributes with this form, the attribute value itself in the
449 .debug\_info or .debug\_types section begins with an unsigned
450 LEB128 number that represents its form. This allows producers
451 to choose forms for particular attributes dynamically,
452 without having to add a new entry to the abbreviations table.
454 The abbreviations for a given compilation unit end with an
455 entry consisting of a 0 byte for the abbreviation code.
458 Appendix \refersec{app:compilationunitsandabbreviationstableexample}
459 for a depiction of the organization of the
460 debugging information.
462 \subsection{Attribute Encodings}
463 \label{datarep:attributeencodings}
465 The encodings for the attribute names are given in
466 Table \refersec{tab:attributeencodings}.
468 The attribute form governs how the value of the attribute is
469 encoded. There are nine classes of form, listed below. Each
470 class is a set of forms which have related representations
471 and which are given a common interpretation according to the
472 attribute in which the form is used.
474 Form \livelink{chap:DWFORMsecoffset}{DW\-\_FORM\-\_sec\-\_offset} is a member of more than one class,
475 namely \livelink{chap:lineptr}{lineptr}, \livelink{chap:loclistptr}{loclistptr}, \livelink{chap:macptr}{macptr} or \livelink{chap:rangelistptr}{rangelistptr}; the list
476 of classes allowed by the applicable attribute in
477 Table \refersec{tab:attributeencodings}
478 determines the class of the form.
480 \textit{In DWARF V3 the forms \livelink{chap:DWFORMdata4}{DW\-\_FORM\-\_data4} and \livelink{chap:DWFORMdata8}{DW\-\_FORM\-\_data8} were
481 members of either class constant or one of the classes \livelink{chap:lineptr}{lineptr},
482 \livelink{chap:loclistptr}{loclistptr}, \livelink{chap:macptr}{macptr} or \livelink{chap:rangelistptr}{rangelistptr}, depending on context. In
483 DWARF V4 \livelink{chap:DWFORMdata4}{DW\-\_FORM\-\_data4} and \livelink{chap:DWFORMdata8}{DW\-\_FORM\-\_data8} are members of class
484 constant in all cases. The new \livelink{chap:DWFORMsecoffset}{DW\-\_FORM\-\_sec\-\_offset} replaces
485 their usage for the other classes.}
487 Each possible form belongs to one or more of the following classes:
491 Represented as an object of appropriate size to hold an
492 address on the target machine
493 (\livetarg{chap:DWFORMaddr}{DW\-\_FORM\-\_addr}). The size is
494 encoded in the compilation unit header
495 (see Section \refersec{datarep:compilationunitheader}).
496 This address is relocatable in a relocatable object file and
497 is relocated in an executable file or shared object.
500 Blocks come in four forms:
502 \begin{myindentpara}{1cm}
503 A 1\dash byte length followed by 0 to 255 contiguous information
504 bytes (\livetarg{chap:DWFORMblock1}{DW\-\_FORM\-\_block1}).
507 \begin{myindentpara}{1cm}
508 A 2\dash byte length followed by 0 to 65,535 contiguous information
509 bytes (\livetarg{chap:DWFORMblock2}{DW\-\_FORM\-\_block2}).
513 \begin{myindentpara}{1cm}
514 A 4\dash byte length followed by 0 to 4,294,967,295 contiguous
515 information bytes (\livetarg{chap:DWFORMblock4}{DW\-\_FORM\-\_block4}).
519 \begin{myindentpara}{1cm}
520 An unsigned LEB128 length followed by the number of bytes
521 specified by the length (\livetarg{chap:DWFORMblock}{DW\-\_FORM\-\_block}).
524 In all forms, the length is the number of information bytes
525 that follow. The information bytes may contain any mixture
526 of relocated (or relocatable) addresses, references to other
527 debugging information entries or data bytes.
530 There are six forms of constants. There are fixed length
531 constant data forms for one, two, four and eight byte values
533 \livetarg{chap:DWFORMdata1}{DW\-\_FORM\-\_data1},
534 \livetarg{chap:DWFORMdata2}{DW\-\_FORM\-\_data2},
535 \livetarg{chap:DWFORMdata4}{DW\-\_FORM\-\_data4},
536 and \livetarg{chap:DWFORMdata8}{DW\-\_FORM\-\_data8}).
537 There are also variable length constant
538 data forms encoded using LEB128 numbers (see below). Both
539 signed (\livetarg{chap:DWFORMsdata}{DW\-\_FORM\-\_sdata}) and unsigned
540 (\livetarg{chap:DWFORMudata}{DW\-\_FORM\-\_udata}) variable
541 length constants are available
543 The data in \livelink{chap:DWFORMdata1}{DW\-\_FORM\-\_data1},
544 \livelink{chap:DWFORMdata2}{DW\-\_FORM\-\_data2},
545 \livelink{chap:DWFORMdata4}{DW\-\_FORM\-\_data4} and
546 \livelink{chap:DWFORMdata8}{DW\-\_FORM\-\_data8}
547 can be anything. Depending on context, it may
548 be a signed integer, an unsigned integer, a floating\dash point
549 constant, or anything else. A consumer must use context to
550 know how to interpret the bits, which if they are target
551 machine data (such as an integer or floating point constant)
552 will be in target machine byte\dash order.
554 \textit{If one of the \livetarg{chap:DWFORMdata}{DW\-\_FORM\-\_data}<n> forms is used to represent a
555 signed or unsigned integer, it can be hard for a consumer
556 to discover the context necessary to determine which
557 interpretation is intended. Producers are therefore strongly
558 encouraged to use \livelink{chap:DWFORMsdata}{DW\-\_FORM\-\_sdata} or
559 \livelink{chap:DWFORMudata}{DW\-\_FORM\-\_udata} for signed and
560 unsigned integers respectively, rather than
561 \livelink{chap:DWFORMdata}{DW\-\_FORM\-\_data} \textless n \textgreater.}
564 \item \livelink{chap:exprloc}{exprloc} \\
565 This is an unsigned LEB128 length followed by the
566 number of information bytes specified by the length
567 (\livetarg{chap:DWFORMexprloc}{DW\-\_FORM\-\_exprloc}).
568 The information bytes contain a DWARF
570 (see Section \refersec{chap:dwarfexpressions})
571 or location description
572 (see Section \refersec{chap:locationdescriptions}).
575 A flag is represented explicitly as a single byte of data
576 (\livetarg{chap:DWFORMflag}{DW\-\_FORM\-\_flag}) or
577 implicitly (\livetarg{chap:DWFORMflagpresent}{DW\-\_FORM\-\_flag\-\_present}). In the
578 first case, if the flag has value zero, it indicates the
579 absence of the attribute; if the flag has a non\dash zero value,
580 it indicates the presence of the attribute. In the second
581 case, the attribute is implicitly indicated as present, and
582 no value is encoded in the debugging information entry itself.
584 \item \livelink{chap:lineptr}{lineptr} \\
585 This is an offset into the .debug\_line section
586 (\livelink{chap:DWFORMsecoffset}{DW\-\_FORM\-\_sec\-\_offset}). It consists of an offset from the
587 beginning of the .debug\_line section to the first byte of
588 the data making up the line number list for the compilation
590 It is relocatable in a relocatable object file, and
591 relocated in an executable or shared object. In the 32\dash bit
592 DWARF format, this offset is a 4\dash byte unsigned value;
593 in the 64\dash bit DWARF format, it is an 8\dash byte unsigned value
594 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
597 \item \livelink{chap:loclistptr}{loclistptr} \\
598 This is an offset into the .debug\_loc section
599 (\livelink{chap:DWFORMsecoffset}{DW\-\_FORM\-\_sec\-\_offset}). It consists of an offset from the
600 beginning of the .debug\_loc section to the first byte of
601 the data making up the location list for the compilation
603 It is relocatable in a relocatable object file, and
604 relocated in an executable or shared object. In the 32\dash bit
605 DWARF format, this offset is a 4\dash byte unsigned value;
606 in the 64\dash bit DWARF format, it is an 8\dash byte unsigned value
607 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
610 \item \livelink{chap:macptr}{macptr} \\
611 This is an offset into the .debug\_macinfo section
612 (\livelink{chap:DWFORMsecoffset}{DW\-\_FORM\-\_sec\-\_offset}). It consists of an offset from the
613 beginning of the .debug\_macinfo section to the first byte of
614 the data making up the macro information list for the compilation
616 It is relocatable in a relocatable object file, and
617 relocated in an executable or shared object. In the 32\dash bit
618 DWARF format, this offset is a 4\dash byte unsigned value;
619 in the 64\dash bit DWARF format, it is an 8\dash byte unsigned value
620 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
622 \item \livelink{chap:rangelistptr}{rangelistptr} \\
623 This is an offset into the .debug\_ranges section
624 (\livelink{chap:DWFORMsecoffset}{DW\-\_FORM\-\_sec\-\_offset}).
626 offset from the beginning of the .debug\_ranges section
627 to the beginning of the non\dash contiguous address ranges
628 information for the referencing entity.
630 a relocatable object file, and relocated in an executable or
631 shared object. In the 32\dash bit DWARF format, this offset
632 is a 4\dash byte unsigned value; in the 64\dash bit DWARF
633 format, it is an 8\dash byte unsigned value (see Section
634 \refersec{datarep:32bitand64bitdwarfformats}).
637 \textit{Because classes \livelink{chap:lineptr}{lineptr}, \livelink{chap:loclistptr}{loclistptr}, \livelink{chap:macptr}{macptr} and \livelink{chap:rangelistptr}{rangelistptr}
638 share a common representation, it is not possible for an
639 attribute to allow more than one of these classes}
644 There are three types of reference.
646 The first type of reference can identify any debugging
647 information entry within the containing unit. This type of
648 reference is an offset from the first byte of the compilation
649 header for the compilation unit containing the reference. There
650 are five forms for this type of reference. There are fixed
651 length forms for one, two, four and eight byte offsets
652 (respectively, \livetarg{chap:DWFORMref1}{DW\-\_FORM\-\_ref1},
653 \livetarg{chap:DWFORMref2}{DW\-\_FORM\-\_ref2},
654 \livetarg{chap:DWFORMref4}{DW\-\_FORM\-\_ref4},
655 and \livetarg{chap:DWFORMref8}{DW\-\_FORM\-\_ref8}).
656 There is also an unsigned variable
657 length offset encoded form that uses unsigned LEB128 numbers
658 (\livetarg{chap:DWFORMrefudata}{DW\-\_FORM\-\_ref\-\_udata}).
659 Because this type of reference is within
660 the containing compilation unit no relocation of the value
663 The second type of reference can identify any debugging
664 information entry within a .debug\_info section; in particular,
665 it may refer to an entry in a different compilation unit
666 from the unit containing the reference, and may refer to an
667 entry in a different shared object. This type of reference
668 (\livetarg{chap:DWFORMrefaddr}{DW\-\_FORM\-\_ref\-\_addr}) is an offset from the beginning of the
669 .debug\_info section of the target executable or shared object;
670 it is relocatable in a relocatable object file and frequently
671 relocated in an executable file or shared object. For
672 references from one shared object or static executable file
673 to another, the relocation and identification of the target
674 object must be performed by the consumer. In the 32\dash bit DWARF
675 format, this offset is a 4\dash byte unsigned value;
676 in the 64\dash bit DWARF format, it is an 8\dash byte
678 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
680 A debugging information entry that may be referenced by
681 another compilation unit using \livelink{chap:DWFORMrefaddr}{DW\-\_FORM\-\_ref\-\_addr} must have a
682 global symbolic name.
684 For a reference from one executable or shared object to
685 another, the reference is resolved by the debugger to identify
686 the shared object or executable and the offset into that
687 object’s .debug\_info section in the same fashion as the run
688 time loader, either when the debug information is first read,
689 or when the reference is used.
691 The third type of reference can identify any debugging
692 information type entry that has been placed in its own
693 type unit. This type of
694 reference (\livetarg{chap:DWFORMrefsig8}{DW\-\_FORM\-\_ref\-\_sig8}) is the
695 64\dash bit type signature
696 (see Section \refersec{datarep:typesignaturecomputation})
700 The use of compilation unit relative references will reduce the
701 number of link\dash time relocations and so speed up linking. The
702 use of the second and third type of reference allows for the
703 sharing of information, such as types, across compilation
706 A reference to any kind of compilation unit identifies the
707 debugging information entry for that unit, not the preceding
711 A string is a sequence of contiguous non\dash null bytes followed by
712 one null byte. A string may be represented immediately in the
713 debugging information entry itself
714 (\livetarg{chap:DWFORMstring}{DW\-\_FORM\-\_string}), or may
715 be represented as an offset into a string table contained in
716 the .debug\_str section of the object file
717 (\livetarg{chap:DWFORMstrp}{DW\-\_FORM\-\_strp}). In
718 the 32\dash bit DWARF format, the representation of a
719 \livelink{chap:DWFORMstrp}{DW\-\_FORM\-\_strp}
720 value is a 4\dash byte unsigned offset; in the 64\dash bit DWARF format,
721 it is an 8\dash byte unsigned offset
722 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
724 If the \livelink{chap:DWATuseUTF8}{DW\-\_AT\-\_use\-\_UTF8} attribute is specified for the
725 compilation unit entry, string values are encoded using the
726 UTF\dash 8 (Unicode Transformation Format\dash 8) from the Universal
727 Character Set standard (ISO/IEC 10646\dash 1:1993). Otherwise,
728 the string representation is unspecified.
730 The Unicode Standard Version 3 is fully compatible with
731 ISO/IEC 10646\dash 1:1993. It contains all the same characters
732 and encoding points as ISO/IEC 10646, as well as additional
733 information about the characters and their use.
735 Earlier versions of DWARF did not specify the representation
736 of strings; for compatibility, this version also does
737 not. However, the UTF\dash 8 representation is strongly recommended.
741 In no case does an attribute use one of the classes \livelink{chap:lineptr}{lineptr},
742 \livelink{chap:loclistptr}{loclistptr}, \livelink{chap:macptr}{macptr} or \livelink{chap:rangelistptr}{rangelistptr} to point into either the
743 .debug\_info or .debug\_str section.
745 The form encodings are listed in
746 Table \refersec{tab:attributeformencodings}.
749 \setlength{\extrarowheight}{0.1cm}
750 \begin{longtable}{l|l}
751 \caption{Tag encodings} \label{tab:tagencodings} \\
752 \hline \\ \bfseries Tag name&\bfseries Value\\ \hline
754 \bfseries Tag name&\bfseries Value \\ \hline
756 \hline \emph{Continued on next page}
760 \livelink{chap:DWTAGarraytype}{DW\-\_TAG\-\_array\-\_type} &0x01 \\
761 \livelink{chap:DWTAGclasstype}{DW\-\_TAG\-\_class\-\_type}&0x02 \\
762 \livelink{chap:DWTAGentrypoint}{DW\-\_TAG\-\_entry\-\_point}&0x03 \\
763 \livelink{chap:DWTAGenumerationtype}{DW\-\_TAG\-\_enumeration\-\_type}&0x04 \\
764 \livelink{chap:DWTAGformalparameter}{DW\-\_TAG\-\_formal\-\_parameter}&0x05 \\
765 \livelink{chap:DWTAGimporteddeclaration}{DW\-\_TAG\-\_imported\-\_declaration}&0x08 \\
766 \livelink{chap:DWTAGlabel}{DW\-\_TAG\-\_label}&0x0a \\
767 \livelink{chap:DWTAGlexicalblock}{DW\-\_TAG\-\_lexical\-\_block}&0x0b \\
768 \livelink{chap:DWTAGmember}{DW\-\_TAG\-\_member}&0x0d \\
769 \livelink{chap:DWTAGpointertype}{DW\-\_TAG\-\_pointer\-\_type}&0x0f \\
770 \livelink{chap:DWTAGreferencetype}{DW\-\_TAG\-\_reference\-\_type}&0x10 \\
771 \livelink{chap:DWTAGcompileunit}{DW\-\_TAG\-\_compile\-\_unit}&0x11 \\
772 \livelink{chap:DWTAGstringtype}{DW\-\_TAG\-\_string\-\_type}&0x12 \\
773 \livelink{chap:DWTAGstructuretype}{DW\-\_TAG\-\_structure\-\_type}&0x13 \\
774 \livelink{chap:DWTAGsubroutinetype}{DW\-\_TAG\-\_subroutine\-\_type}&0x15 \\
775 \livelink{chap:DWTAGtypedef}{DW\-\_TAG\-\_typedef}&0x16 \\
776 \livelink{chap:DWTAGuniontype}{DW\-\_TAG\-\_union\-\_type}&0x17 \\
777 \livelink{chap:DWTAGunspecifiedparameters}{DW\-\_TAG\-\_unspecified\-\_parameters}&0x18 \\
778 \livelink{chap:DWTAGvariant}{DW\-\_TAG\-\_variant}&0x19 \\
779 \livelink{chap:DWTAGcommonblock}{DW\-\_TAG\-\_common\-\_block}&0x1a \\
780 \livelink{chap:DWTAGcommoninclusion}{DW\-\_TAG\-\_common\-\_inclusion}&0x1b \\
781 \livelink{chap:DWTAGinheritance}{DW\-\_TAG\-\_inheritance}&0x1c \\
782 \livelink{chap:DWTAGinlinedsubroutine}{DW\-\_TAG\-\_inlined\-\_subroutine}&0x1d \\
783 \livelink{chap:DWTAGmodule}{DW\-\_TAG\-\_module}&0x1e \\
784 \livelink{chap:DWTAGptrtomembertype}{DW\-\_TAG\-\_ptr\-\_to\-\_member\-\_type}&0x1f \\
785 \livelink{chap:DWTAGsettype}{DW\-\_TAG\-\_set\-\_type}&0x20 \\
786 \livelink{chap:DWTAGsubrangetype}{DW\-\_TAG\-\_subrange\-\_type}&0x21 \\
787 \livelink{chap:DWTAGwithstmt}{DW\-\_TAG\-\_with\-\_stmt}&0x22 \\
788 \livelink{chap:DWTAGaccessdeclaration}{DW\-\_TAG\-\_access\-\_declaration}&0x23 \\
789 \livelink{chap:DWTAGbasetype}{DW\-\_TAG\-\_base\-\_type}&0x24 \\
790 \livelink{chap:DWTAGcatchblock}{DW\-\_TAG\-\_catch\-\_block}&0x25 \\
791 \livelink{chap:DWTAGconsttype}{DW\-\_TAG\-\_const\-\_type}&0x26 \\
792 \livelink{chap:DWTAGconstant}{DW\-\_TAG\-\_constant}&0x27 \\
793 \livelink{chap:DWTAGenumerator}{DW\-\_TAG\-\_enumerator}&0x28 \\
794 \livelink{chap:DWTAGfiletype}{DW\-\_TAG\-\_file\-\_type}&0x29 \\
795 \livelink{chap:DWTAGfriend}{DW\-\_TAG\-\_friend}&0x2a \\
796 \livelink{chap:DWTAGnamelist}{DW\-\_TAG\-\_namelist}&0x2b \\
797 \livelink{chap:DWTAGnamelistitem}{DW\-\_TAG\-\_namelist\-\_item}&0x2c \\
798 \livelink{chap:DWTAGpackedtype}{DW\-\_TAG\-\_packed\-\_type}&0x2d \\
799 \livelink{chap:DWTAGsubprogram}{DW\-\_TAG\-\_subprogram}&0x2e \\
800 \livelink{chap:DWTAGtemplatetypeparameter}{DW\-\_TAG\-\_template\-\_type\-\_parameter}&0x2f \\
801 \livelink{chap:DWTAGtemplatevalueparameter}{DW\-\_TAG\-\_template\-\_value\-\_parameter}&0x30 \\
802 \livelink{chap:DWTAGthrowntype}{DW\-\_TAG\-\_thrown\-\_type}&0x31 \\
803 \livelink{chap:DWTAGtryblock}{DW\-\_TAG\-\_try\-\_block}&0x32 \\
804 \livelink{chap:DWTAGvariantpart}{DW\-\_TAG\-\_variant\-\_part}&0x33 \\
805 \livelink{chap:DWTAGvariable}{DW\-\_TAG\-\_variable}&0x34 \\
806 \livelink{chap:DWTAGvolatiletype}{DW\-\_TAG\-\_volatile\-\_type}&0x35 \\
807 \livelink{chap:DWTAGdwarfprocedure}{DW\-\_TAG\-\_dwarf\-\_procedure}&0x36 \\
808 \livelink{chap:DWTAGrestricttype}{DW\-\_TAG\-\_restrict\-\_type}&0x37 \\
809 \livelink{chap:DWTAGinterfacetype}{DW\-\_TAG\-\_interface\-\_type}&0x38 \\
810 \livelink{chap:DWTAGnamespace}{DW\-\_TAG\-\_namespace}&0x39 \\
811 \livelink{chap:DWTAGimportedmodule}{DW\-\_TAG\-\_imported\-\_module}&0x3a \\
812 \livelink{chap:DWTAGunspecifiedtype}{DW\-\_TAG\-\_unspecified\-\_type}&0x3b \\
813 \livelink{chap:DWTAGpartialunit}{DW\-\_TAG\-\_partial\-\_unit}&0x3c \\
814 \livelink{chap:DWTAGimportedunit}{DW\-\_TAG\-\_imported\-\_unit}&0x3d \\
815 \livelink{chap:DWTAGcondition}{DW\-\_TAG\-\_condition}&0x3f \\
816 \livelink{chap:DWTAGsharedtype}{DW\-\_TAG\-\_shared\-\_type}&0x40 \\
817 \livelink{chap:DWTAGtypeunit}{DW\-\_TAG\-\_type\-\_unit} \ddag &0x41 \\
818 \livelink{chap:DWTAGrvaluereferencetype}{DW\-\_TAG\-\_rvalue\-\_reference\-\_type} \ddag &0x42 \\
819 \livelink{chap:DWTAGtemplatealias}{DW\-\_TAG\-\_template\-\_alias} \ddag &0x43 \\
820 \livelink{chap:DWTAGlouser}{DW\-\_TAG\-\_lo\-\_user}&0x4080 \\
821 \livelink{chap:DWTAGhiuser}{DW\-\_TAG\-\_hi\-\_user}&0xffff \\
823 \ddag TAG new in DWARF Version 4
829 \setlength{\extrarowheight}{0.1cm}
830 \caption{Child determination encodings}
831 \label{tab:childdeterminationencodings}
832 \begin{tabular}{l|l} \hline
833 Child determination name& Value\\ \hline
834 \livelink{chap:DWCHILDRENno}{DW\-\_CHILDREN\-\_no}&0x00 \\
835 \livelink{chap:DWCHILDRENyes}{DW\-\_CHILDREN\-\_yes}&0x01 \\ \hline
841 \setlength{\extrarowheight}{0.1cm}
842 \begin{longtable}{l|l|l}
843 \caption{Attribute encodings} \label{tab:attributeencodings} \\
844 \hline \\ \bfseries Attribute name&\bfseries Value &\bfseries Classes \\ \hline
846 \bfseries Attribute name&\bfseries Value &\bfseries Classes\\ \hline
848 \hline \emph{Continued on next page}
852 \livelink{chap:DWATsibling}{DW\-\_AT\-\_sibling}&0x01&reference \\
853 \livelink{chap:DWATlocation}{DW\-\_AT\-\_location}&0x02&\livelink{chap:exprloc}{exprloc}, \livelink{chap:loclistptr}{loclistptr} \\
854 \livelink{chap:DWATname}{DW\-\_AT\-\_name}&0x03&string \\
855 \livelink{chap:DWATordering}{DW\-\_AT\-\_ordering}&0x09&constant \\
856 \livelink{chap:DWATbytesize}{DW\-\_AT\-\_byte\-\_size}&0x0b&constant, \livelink{chap:exprloc}{exprloc}, reference \\
857 \livelink{chap:DWATbitoffset}{DW\-\_AT\-\_bit\-\_offset}&0x0c&constant, \livelink{chap:exprloc}{exprloc}, reference \\
858 \livelink{chap:DWATbitsize}{DW\-\_AT\-\_bit\-\_size}&0x0d&constant, \livelink{chap:exprloc}{exprloc}, reference \\
859 \livelink{chap:DWATstmtlist}{DW\-\_AT\-\_stmt\-\_list}&0x10&\livelink{chap:lineptr}{lineptr} \\
860 \livelink{chap:DWATlowpc}{DW\-\_AT\-\_low\-\_pc}&0x11&address \\
861 \livelink{chap:DWAThighpc}{DW\-\_AT\-\_high\-\_pc}&0x12&address, constant \\
862 \livelink{chap:DWATlanguage}{DW\-\_AT\-\_language}&0x13&constant \\
863 \livelink{chap:DWATdiscr}{DW\-\_AT\-\_discr}&0x15&reference \\
864 \livelink{chap:DWATdiscrvalue}{DW\-\_AT\-\_discr\-\_value}&0x16&constant \\
865 \livelink{chap:DWATvisibility}{DW\-\_AT\-\_visibility}&0x17&constant \\
866 \livelink{chap:DWATimport}{DW\-\_AT\-\_import}&0x18&reference \\
867 \livelink{chap:DWATstringlength}{DW\-\_AT\-\_string\-\_length}&0x19&\livelink{chap:exprloc}{exprloc}, \livelink{chap:loclistptr}{loclistptr} \\
868 \livelink{chap:DWATcommonreference}{DW\-\_AT\-\_common\-\_reference}&0x1a&reference \\
869 \livelink{chap:DWATcompdir}{DW\-\_AT\-\_comp\-\_dir}&0x1b&string \\
870 \livelink{chap:DWATconstvalue}{DW\-\_AT\-\_const\-\_value}&0x1c&block, constant, string \\
871 \livelink{chap:DWATcontainingtype}{DW\-\_AT\-\_containing\-\_type}&0x1d&reference \\
872 \livelink{chap:DWATdefaultvalue}{DW\-\_AT\-\_default\-\_value}&0x1e&reference \\
873 \livelink{chap:DWATinline}{DW\-\_AT\-\_inline}&0x20&constant \\
874 \livelink{chap:DWATisoptional}{DW\-\_AT\-\_is\-\_optional}&0x21&flag \\
875 \livelink{chap:DWATlowerbound}{DW\-\_AT\-\_lower\-\_bound}&0x22&constant, \livelink{chap:exprloc}{exprloc}, reference \\
876 \livelink{chap:DWATproducer}{DW\-\_AT\-\_producer}&0x25&string \\
877 \livelink{chap:DWATprototyped}{DW\-\_AT\-\_prototyped}&0x27&flag \\
878 \livelink{chap:DWATreturnaddr}{DW\-\_AT\-\_return\-\_addr}&0x2a&\livelink{chap:exprloc}{exprloc}, \livelink{chap:loclistptr}{loclistptr} \\
879 % FIXME: lower case , not Constant
880 \livelink{chap:DWATstartscope}{DW\-\_AT\-\_start\-\_scope}&0x2c&Constant, \livelink{chap:rangelistptr}{rangelistptr} \\
881 \livelink{chap:DWATbitstride}{DW\-\_AT\-\_bit\-\_stride}&0x2e&constant, \livelink{chap:exprloc}{exprloc}, reference \\
882 \livelink{chap:DWATupperbound}{DW\-\_AT\-\_upper\-\_bound}&0x2f&constant, \livelink{chap:exprloc}{exprloc}, reference \\
883 \livelink{chap:DWATabstractorigin}{DW\-\_AT\-\_abstract\-\_origin}&0x31&reference \\
884 \livelink{chap:DWATaccessibility}{DW\-\_AT\-\_accessibility}&0x32&constant \\
885 \livelink{chap:DWATaddressclass}{DW\-\_AT\-\_address\-\_class}&0x33&constant \\
886 \livelink{chap:DWATartificial}{DW\-\_AT\-\_artificial}&0x34&flag \\
887 \livelink{chap:DWATbasetypes}{DW\-\_AT\-\_base\-\_types}&0x35&reference \\
888 \livelink{chap:DWATcallingconvention}{DW\-\_AT\-\_calling\-\_convention}&0x36&constant \\
889 \livelink{chap:DWATcount}{DW\-\_AT\-\_count}&0x37&constant, \livelink{chap:exprloc}{exprloc}, reference \\
890 \livelink{chap:DWATdatamemberlocation}{DW\-\_AT\-\_data\-\_member\-\_location}&0x38&constant, \livelink{chap:exprloc}{exprloc}, \livelink{chap:loclistptr}{loclistptr} \\
891 \livelink{chap:DWATdeclcolumn}{DW\-\_AT\-\_decl\-\_column}&0x39&constant \\
892 \livelink{chap:DWATdeclfile}{DW\-\_AT\-\_decl\-\_file}&0x3a&constant \\
893 \livelink{chap:DWATdeclline}{DW\-\_AT\-\_decl\-\_line}&0x3b&constant \\
894 \livelink{chap:DWATdeclaration}{DW\-\_AT\-\_declaration}&0x3c&flag \\
895 \livelink{chap:DWATdiscrlist}{DW\-\_AT\-\_discr\-\_list}&0x3d&block \\
896 \livelink{chap:DWATencoding}{DW\-\_AT\-\_encoding}&0x3e&constant \\
897 \livelink{chap:DWATexternal}{DW\-\_AT\-\_external}&0x3f&flag \\
898 \livelink{chap:DWATframebase}{DW\-\_AT\-\_frame\-\_base}&0x40&\livelink{chap:exprloc}{exprloc}, \livelink{chap:loclistptr}{loclistptr} \\
899 \livelink{chap:DWATfriend}{DW\-\_AT\-\_friend}&0x41&reference \\
900 \livelink{chap:DWATidentifiercase}{DW\-\_AT\-\_identifier\-\_case}&0x42&constant \\
901 \livelink{chap:DWATmacroinfo}{DW\-\_AT\-\_macro\-\_info}&0x43&\livelink{chap:macptr}{macptr} \\
902 \livelink{chap:DWATnamelistitem}{DW\-\_AT\-\_namelist\-\_item}&0x44&reference \\
903 \livelink{chap:DWATpriority}{DW\-\_AT\-\_priority}&0x45&reference \\
904 \livelink{chap:DWATsegment}{DW\-\_AT\-\_segment}&0x46&\livelink{chap:exprloc}{exprloc}, \livelink{chap:loclistptr}{loclistptr} \\
905 \livelink{chap:DWATspecification}{DW\-\_AT\-\_specification}&0x47&reference \\
906 \livelink{chap:DWATstaticlink}{DW\-\_AT\-\_static\-\_link}&0x48&\livelink{chap:exprloc}{exprloc}, \livelink{chap:loclistptr}{loclistptr} \\
907 \livelink{chap:DWATtype}{DW\-\_AT\-\_type}&0x49&reference \\
908 \livelink{chap:DWATuselocation}{DW\-\_AT\-\_use\-\_location}&0x4a&\livelink{chap:exprloc}{exprloc}, \livelink{chap:loclistptr}{loclistptr} \\
909 \livelink{chap:DWATvariableparameter}{DW\-\_AT\-\_variable\-\_parameter}&0x4b&flag \\
910 \livelink{chap:DWATvirtuality}{DW\-\_AT\-\_virtuality}&0x4c&constant \\
911 \livelink{chap:DWATvtableelemlocation}{DW\-\_AT\-\_vtable\-\_elem\-\_location}&0x4d&\livelink{chap:exprloc}{exprloc}, \livelink{chap:loclistptr}{loclistptr} \\
914 \livelink{chap:DWATallocated}{DW\-\_AT\-\_allocated}&0x4e&constant, \livelink{chap:exprloc}{exprloc}, reference \\
915 \livelink{chap:DWATassociated}{DW\-\_AT\-\_associated}&0x4f&constant, \livelink{chap:exprloc}{exprloc}, reference \\
916 \livelink{chap:DWATdatalocation}{DW\-\_AT\-\_data\-\_location}&0x50&\livelink{chap:exprloc}{exprloc} \\
917 \livelink{chap:DWATbytestride}{DW\-\_AT\-\_byte\-\_stride}&0x51&constant, \livelink{chap:exprloc}{exprloc}, reference \\
918 \livelink{chap:DWATentrypc}{DW\-\_AT\-\_entry\-\_pc}&0x52&address \\
919 \livelink{chap:DWATuseUTF8}{DW\-\_AT\-\_use\-\_UTF8}&0x53&flag \\
920 \livelink{chap:DWATextension}{DW\-\_AT\-\_extension}&0x54&reference \\
921 \livelink{chap:DWATranges}{DW\-\_AT\-\_ranges}&0x55&\livelink{chap:rangelistptr}{rangelistptr} \\
922 \livelink{chap:DWATtrampoline}{DW\-\_AT\-\_trampoline}&0x56&address, flag, reference, string \\
923 \livelink{chap:DWATcallcolumn}{DW\-\_AT\-\_call\-\_column}&0x57&constant \\
924 \livelink{chap:DWATcallfile}{DW\-\_AT\-\_call\-\_file}&0x58&constant \\
925 \livelink{chap:DWATcallline}{DW\-\_AT\-\_call\-\_line}&0x59&constant \\
926 \livelink{chap:DWATdescription}{DW\-\_AT\-\_description}&0x5a&string \\
927 \livelink{chap:DWATbinaryscale}{DW\-\_AT\-\_binary\-\_scale}&0x5b&constant \\
928 \livelink{chap:DWATdecimalscale}{DW\-\_AT\-\_decimal\-\_scale}&0x5c&constant \\
929 \livelink{chap:DWATsmall}{DW\-\_AT\-\_small} &0x5d&reference \\
930 \livelink{chap:DWATdecimalsign}{DW\-\_AT\-\_decimal\-\_sign}&0x5e&constant \\
931 \livelink{chap:DWATdigitcount}{DW\-\_AT\-\_digit\-\_count}&0x5f&constant \\
932 \livelink{chap:DWATpicturestring}{DW\-\_AT\-\_picture\-\_string}&0x60&string \\
933 \livelink{chap:DWATmutable}{DW\-\_AT\-\_mutable}&0x61&flag \\
936 \livelink{chap:DWATthreadsscaled}{DW\-\_AT\-\_threads\-\_scaled}&0x62&flag \\
937 \livelink{chap:DWATexplicit}{DW\-\_AT\-\_explicit}&0x63&flag \\
938 \livelink{chap:DWATobjectpointer}{DW\-\_AT\-\_object\-\_pointer}&0x64&reference \\
939 \livelink{chap:DWATendianity}{DW\-\_AT\-\_endianity}&0x65&constant \\
940 \livelink{chap:DWATelemental}{DW\-\_AT\-\_elemental}&0x66&flag \\
941 \livelink{chap:DWATpure}{DW\-\_AT\-\_pure}&0x67&flag \\
942 \livelink{chap:DWATrecursive}{DW\-\_AT\-\_recursive}&0x68&flag \\
943 \livelink{chap:DWATsignature}{DW\-\_AT\-\_signature} \ddag &0x69&reference \\
944 \livelink{chap:DWATmainsubprogram}{DW\-\_AT\-\_main\-\_subprogram} \ddag &0x6a&flag \\
945 \livelink{chap:DWATdatabitoffset}{DW\-\_AT\-\_data\-\_bit\-\_offset} \ddag &0x6b&constant \\
946 \livelink{chap:DWATconstexpr}{DW\-\_AT\-\_const\-\_expr} \ddag &0x6c&flag \\
947 \livelink{chap:DWATenumclass}{DW\-\_AT\-\_enum\-\_class} \ddag &0x6d&flag \\
948 \livelink{chap:DWATlinkagename}{DW\-\_AT\-\_linkage\-\_name} \ddag &0x6e&string \\
949 \livetarg{chap:DWATlouser}{DW\-\_AT\-\_lo\-\_user}&0x2000 & --- \\
950 \livetarg{chap:DWAThiuser}{DW\-\_AT\-\_hi\-\_user}&0x3fff& --- \\
953 \ddag Attribute new in DWARF Version 4
957 \setlength{\extrarowheight}{0.1cm}
958 \begin{longtable}{l|l|l}
959 \caption{Attribute form encodings} \label{tab:attributeformencodings} \\
960 \hline \\ \bfseries Form name&\bfseries Value &\bfseries Classes \\ \hline
962 \bfseries Form name&\bfseries Value &\bfseries Classes\\ \hline
964 \hline \emph{Continued on next page}
968 \livelink{chap:DWFORMaddr}{DW\-\_FORM\-\_addr}&0x01&address \\
969 \livelink{chap:DWFORMblock2}{DW\-\_FORM\-\_block2}&0x03&block \\
970 \livelink{chap:DWFORMblock4}{DW\-\_FORM\-\_block4}&0x04&block \\
971 \livelink{chap:DWFORMdata2}{DW\-\_FORM\-\_data2}&0x05&constant \\
972 \livelink{chap:DWFORMdata4}{DW\-\_FORM\-\_data4}&0x06&constant \\
973 \livelink{chap:DWFORMdata8}{DW\-\_FORM\-\_data8}&0x07&constant \\
974 \livelink{chap:DWFORMstring}{DW\-\_FORM\-\_string}&0x08&string \\
975 \livelink{chap:DWFORMblock}{DW\-\_FORM\-\_block}&0x09&block \\
976 \livelink{chap:DWFORMblock1}{DW\-\_FORM\-\_block1}&0x0a&block \\
977 \livelink{chap:DWFORMdata1}{DW\-\_FORM\-\_data1}&0x0b&constant \\
978 \livelink{chap:DWFORMflag}{DW\-\_FORM\-\_flag}&0x0c&flag \\
979 \livelink{chap:DWFORMsdata}{DW\-\_FORM\-\_sdata}&0x0d&constant \\
980 \livelink{chap:DWFORMstrp}{DW\-\_FORM\-\_strp}&0x0e&string \\
981 \livelink{chap:DWFORMudata}{DW\-\_FORM\-\_udata}&0x0f&constant \\
982 \livelink{chap:DWFORMrefaddr}{DW\-\_FORM\-\_ref\-\_addr}&0x10&reference \\
983 \livelink{chap:DWFORMref1}{DW\-\_FORM\-\_ref1}&0x11&reference \\
984 \livelink{chap:DWFORMref2}{DW\-\_FORM\-\_ref2}&0x12&reference \\
985 \livelink{chap:DWFORMref4}{DW\-\_FORM\-\_ref4}&0x13&reference \\
986 \livelink{chap:DWFORMref8}{DW\-\_FORM\-\_ref8}&0x14&reference \\
987 \livelink{chap:DWFORMrefudata}{DW\-\_FORM\-\_ref\-\_udata}&0x15&reference \\
988 \livelink{chap:DWFORMindirect}{DW\-\_FORM\-\_indirect}&0x16&(see Section \refersec{datarep:abbreviationstables}) \\
989 \livelink{chap:DWFORMsecoffset}{DW\-\_FORM\-\_sec\-\_offset} \ddag &0x17&\livelink{chap:lineptr}{lineptr}, \livelink{chap:loclistptr}{loclistptr}, \livelink{chap:macptr}{macptr}, \livelink{chap:rangelistptr}{rangelistptr} \\
990 \livelink{chap:DWFORMexprloc}{DW\-\_FORM\-\_exprloc} \ddag &0x18&\livelink{chap:exprloc}{exprloc} \\
991 \livelink{chap:DWFORMflagpresent}{DW\-\_FORM\-\_flag\-\_present} \ddag &0x19&flag \\
992 \livelink{chap:DWFORMrefsig8}{DW\-\_FORM\-\_ref\-\_sig8} \ddag &0x20&reference \\
995 \ddag FORM new in DWARF Version 4
998 \section{Variable Length Data}
999 \label{datarep:variablelengthdata}
1000 Integers may be encoded using ``Little Endian Base 128''
1001 (LEB128) numbers. LEB128 is a scheme for encoding integers
1002 densely that exploits the assumption that most integers are
1005 This encoding is equally suitable whether the target machine
1006 architecture represents data in big\dash\ endian or little\dash endian
1007 order. It is ``little\dash endian'' only in the sense that it
1008 avoids using space to represent the ``big'' end of an
1009 unsigned integer, when the big end is all zeroes or sign
1012 Unsigned LEB128 (ULEB128) numbers are encoded as follows:
1013 start at the low order end of an unsigned integer and chop
1014 it into 7\dash bit chunks. Place each chunk into the low order 7
1015 bits of a byte. Typically, several of the high order bytes
1016 will be zero; discard them. Emit the remaining bytes in a
1017 stream, starting with the low order byte; set the high order
1018 bit on each byte except the last emitted byte. The high bit
1019 of zero on the last byte indicates to the decoder that it
1020 has encountered the last byte.
1022 The integer zero is a special case, consisting of a single
1025 Table \refersec{tab:examplesofunsignedleb128encodings}
1026 gives some examples of unsigned LEB128 numbers. The
1027 0x80 in each case is the high order bit of the byte, indicating
1028 that an additional byte follows.
1031 The encoding for signed, two’s complement LEB128 (SLEB128)
1032 numbers is similar, except that the criterion for discarding
1033 high order bytes is not whether they are zero, but whether
1034 they consist entirely of sign extension bits. Consider the
1035 32\dash bit integer -2. The three high level bytes of the number
1036 are sign extension, thus LEB128 would represent it as a single
1037 byte containing the low order 7 bits, with the high order
1038 bit cleared to indicate the end of the byte stream. Note
1039 that there is nothing within the LEB128 representation that
1040 indicates whether an encoded number is signed or unsigned. The
1041 decoder must know what type of number to expect.
1042 Table \refersec{tab:examplesofunsignedleb128encodings}
1043 gives some examples of unsigned LEB128 numbers and
1044 Table \refersec{tab:examplesofsignedleb128encodings}
1045 gives some examples of signed LEB128 numbers.
1047 Appendix \refersec{app:variablelengthdataencodingdecodinginformative}
1048 gives algorithms for encoding and decoding these forms.
1052 \setlength{\extrarowheight}{0.1cm}
1053 \begin{longtable}{l|l|l}
1054 \caption{Examples of unsigned LEB32 encodings} \label{tab:examplesofunsignedleb128encodings} \\
1055 \hline \\ \bfseries Number&\bfseries First byte &\bfseries Second byte \\ \hline
1057 \bfseries Number&\bfseries First Byte &\bfseries Second byte\\ \hline
1059 \hline \emph{Continued on next page}
1065 128& 0 + 0x80 & 1 \\
1066 129& 1 + 0x80 & 1 \\
1067 130& 2 + 0x80 & 1 \\
1068 12857& 57 + 0x80 & 100 \\
1076 \setlength{\extrarowheight}{0.1cm}
1077 \begin{longtable}{l|l|l}
1078 \caption{Examples of signed LEB32 encodings} \label{tab:examplesofsignedleb128encodings} \\
1079 \hline \\ \bfseries Number&\bfseries First byte &\bfseries Second byte \\ \hline
1081 \bfseries Number&\bfseries First Byte &\bfseries Second byte\\ \hline
1083 \hline \emph{Continued on next page}
1089 127& 127 + 0x80 & 0 \\
1090 -127& 1 + 0x80 & 0x7f \\
1091 128& 0 + 0x80 & 1 \\
1092 -128& 0 + 0x80 & 0x7f \\
1093 129& 1 + 0x80 & 1 \\
1094 -129& -x7f + 0x80 & 0xtc \\
1101 \section{DWARF Expressions and Location Descriptions}
1102 \label{datarep:dwarfexpressionsandlocationdescriptions}
1103 \subsection{DWARF Expressions}
1104 \label{datarep:dwarfexpressions}
1106 A DWARF expression is stored in a block of contiguous
1107 bytes. The bytes form a sequence of operations. Each operation
1108 is a 1\dash byte code that identifies that operation, followed by
1109 zero or more bytes of additional data. The encodings for the
1110 operations are described in
1111 Table \refersec{tab:dwarfoperationencodings}.
1114 \setlength{\extrarowheight}{0.1cm}
1115 \begin{longtable}{l|l|l|l}
1116 \caption{DWARF operation encodings} \label{tab:dwarfoperationencodings} \\
1117 \hline \\ & &\bfseries No. of &\\
1118 \bfseries Operation&\bfseries Code &\bfseries Operands &\bfseries Notes\\ \hline
1120 & &\bfseries No. of &\\
1121 \bfseries Operation&\bfseries Code &\bfseries Operands &\bfseries Notes\\ \hline
1123 \hline \emph{Continued on next page}
1128 \livelink{chap:DWOPaddr}{DW\-\_OP\-\_addr}&0x03&1 & constant address \\
1129 & & &(size target specific) \\
1131 \livelink{chap:DWOPderef}{DW\-\_OP\-\_deref}&0x06&0 & \\
1134 \livelink{chap:DWOPconst1u}{DW\-\_OP\-\_const1u}&0x08&1&1\dash byte constant \\
1135 \livelink{chap:DWOPconst1s}{DW\-\_OP\-\_const1s}&0x09&1&1\dash byte constant \\
1136 \livelink{chap:DWOPconst2u}{DW\-\_OP\-\_const2u}&0x0a&1&2\dash byte constant \\
1137 \livelink{chap:DWOPconst2s}{DW\-\_OP\-\_const2s}&0x0b&1&2\dash byte constant \\
1138 \livelink{chap:DWOPconst4u}{DW\-\_OP\-\_const4u}&0x0c&1&4\dash byte constant \\
1139 \livelink{chap:DWOPconst4s}{DW\-\_OP\-\_const4s}&0x0d&1&4\dash byte constant \\
1140 \livelink{chap:DWOPconst8u}{DW\-\_OP\-\_const8u}&0x0e&1&8\dash byte constant \\
1141 \livelink{chap:DWOPconst8s}{DW\-\_OP\-\_const8s}&0x0f&1&8\dash byte constant \\
1142 \livelink{chap:DWOPconstu}{DW\-\_OP\-\_constu}&0x10&1&ULEB128 constant \\
1143 \livelink{chap:DWOPconsts}{DW\-\_OP\-\_consts}&0x11&1&SLEB128 constant \\
1144 \livelink{chap:DWOPdup}{DW\-\_OP\-\_dup}&0x12&0 & \\
1145 \livelink{chap:DWOPdrop}{DW\-\_OP\-\_drop}&0x13&0 & \\
1146 \livelink{chap:DWOPover}{DW\-\_OP\-\_over}&0x14&0 & \\
1147 \livelink{chap:DWOPpick}{DW\-\_OP\-\_pick}&0x15&1&1\dash byte stack index \\
1148 \livelink{chap:DWOPswap}{DW\-\_OP\-\_swap}&0x16&0 & \\
1149 \livelink{chap:DWOProt}{DW\-\_OP\-\_rot}&0x17&0 & \\
1150 \livelink{chap:DWOPxderef}{DW\-\_OP\-\_xderef}&0x18&0 & \\
1151 \livelink{chap:DWOPabs}{DW\-\_OP\-\_abs}&0x19&0 & \\
1152 \livelink{chap:DWOPand}{DW\-\_OP\-\_and}&0x1a&0 & \\
1153 \livelink{chap:DWOPdiv}{DW\-\_OP\-\_div}&0x1b&0 & \\
1157 \livelink{chap:DWOPminus}{DW\-\_OP\-\_minus}&0x1c&0 & \\
1158 \livelink{chap:DWOPmod}{DW\-\_OP\-\_mod}&0x1d&0 & \\
1159 \livelink{chap:DWOPmul}{DW\-\_OP\-\_mul}&0x1e&0 & \\
1160 \livelink{chap:DWOPneg}{DW\-\_OP\-\_neg}&0x1f&0 & \\
1161 \livelink{chap:DWOPnot}{DW\-\_OP\-\_not}&0x20&0 & \\
1162 \livelink{chap:DWOPor}{DW\-\_OP\-\_or}&0x21&0 & \\
1163 \livelink{chap:DWOPplus}{DW\-\_OP\-\_plus}&0x22&0 & \\
1164 \livelink{chap:DWOPplusuconst}{DW\-\_OP\-\_plus\-\_uconst}&0x23&1&ULEB128 addend \\
1165 \livelink{chap:DWOPshl}{DW\-\_OP\-\_shl}&0x24&0 & \\
1166 \livelink{chap:DWOPshr}{DW\-\_OP\-\_shr}&0x25&0 & \\
1167 \livelink{chap:DWOPshra}{DW\-\_OP\-\_shra}&0x26&0 & \\
1168 \livelink{chap:DWOPxor}{DW\-\_OP\-\_xor}&0x27&0 & \\
1169 \livelink{chap:DWOPskip}{DW\-\_OP\-\_skip}&0x2f&1&signed 2\dash byte constant \\
1170 \livelink{chap:DWOPbra}{DW\-\_OP\-\_bra}&0x28&1 & signed 2\dash byte constant \\
1171 \livelink{chap:DWOPeq}{DW\-\_OP\-\_eq}&0x29&0 & \\
1172 \livelink{chap:DWOPge}{DW\-\_OP\-\_ge}&0x2a&0 & \\
1173 \livelink{chap:DWOPgt}{DW\-\_OP\-\_gt}&0x2b&0 & \\
1174 \livelink{chap:DWOPle}{DW\-\_OP\-\_le}&0x2c&0 & \\
1175 \livelink{chap:DWOPlt}{DW\-\_OP\-\_lt}&0x2d&0 & \\
1176 \livelink{chap:DWOPne}{DW\-\_OP\-\_ne}&0x2e&0 & \\ \hline
1180 \livelink{chap:DWOPlit0}{DW\-\_OP\-\_lit0}&0x30 & 0 & \\
1182 \livelink{chap:DWOPlit1}{DW\-\_OP\-\_lit1}&0x31 & 0& literals 0 .. 31 = \\
1183 \ldots & & & (\livelink{chap:DWOPlit0}{DW\-\_OP\-\_lit0} + literal) \\
1184 \livelink{chap:DWOPlit31}{DW\-\_OP\-\_lit31}&0x4f & 0 & \\ \hline
1186 \livelink{chap:DWOPreg0}{DW\-\_OP\-\_reg0} & 0x50 & 0 & \\
1187 \livelink{chap:DWOPreg1}{DW\-\_OP\-\_reg1} & 0x51 & 0® 0 .. 31 = \\
1188 \ldots & & & (\livelink{chap:DWOPreg0}{DW\-\_OP\-\_reg0} + regnum) \\
1189 \livelink{chap:DWOPreg31}{DW\-\_OP\-\_reg31} & 0x6f & 0 & \\ \hline
1191 \livelink{chap:DWOPbreg0}{DW\-\_OP\-\_breg0} & 0x70 &1 & SLEB128 offset \\
1192 \livelink{chap:DWOPbreg1}{DW\-\_OP\-\_breg1} & 0x71 & 1 &base register 0 .. 31 = \\
1193 ... & & &(\livelink{chap:DWOPbreg0}{DW\-\_OP\-\_breg0} + regnum) \\
1194 \livelink{chap:DWOPbreg31}{DW\-\_OP\-\_breg31} & 0x8f & 1 & \\ \hline
1196 \livelink{chap:DWOPregx}{DW\-\_OP\-\_regx} & 0x90 &1&ULEB128 register \\
1197 \livelink{chap:DWOPfbreg}{DW\-\_OP\-\_fbreg} & 0x91&1&SLEB128 offset \\
1198 \livelink{chap:DWOPbregx}{DW\-\_OP\-\_bregx} & 0x92&2 &ULEB128 register followed \\
1199 & & & by SLEB128 offset \\
1200 \livelink{chap:DWOPpiece}{DW\-\_OP\-\_piece} & 0x93 &1& ULEB128 size of piece addressed \\
1201 \livelink{chap:DWOPderefsize}{DW\-\_OP\-\_deref\-\_size} & 0x94 &1& 1-byte size of data retrieved \\
1202 \livelink{chap:DWOPxderefsize}{DW\-\_OP\-\_xderef\-\_size} & 0x95&1&1-byte size of data retrieved \\
1203 \livelink{chap:DWOPnop}{DW\-\_OP\-\_nop} & 0x96 &0& \\
1206 \livelink{chap:DWOPpushobjectaddress}{DW\-\_OP\-\_push\-\_object\-\_address}&0x97&0 & \\
1207 \livelink{chap:DWOPcall2}{DW\-\_OP\-\_call2}&0x98&1& 2\dash byte offset of DIE \\
1208 \livelink{chap:DWOPcall4}{DW\-\_OP\-\_call4}&0x99&1& 4\dash byte offset of DIE \\
1209 \livelink{chap:DWOPcallref}{DW\-\_OP\-\_call\-\_ref}&0x9a&1& 4\dash\ or 8\dash byte\\
1210 &&& offset of DIE \\
1211 \livelink{chap:DWOPformtlsaddress}{DW\-\_OP\-\_form\-\_tls\-\_address}&0x9b &0& \\
1212 \livelink{chap:DWOPcallframecfa}{DW\-\_OP\-\_call\-\_frame\-\_cfa} &0x9c &0& \\
1213 \livelink{chap:DWOPbitpiece}{DW\-\_OP\-\_bit\-\_piece}&0x9d &2&ULEB128 size followed by \\
1215 \livelink{chap:DWOPimplicitvalue}{DW\-\_OP\-\_implicit\-\_value}&0x9e &2&ULEB128 size followed by \\
1216 &&&block of that size\\
1217 \livelink{chap:DWOPstackvalue}{DW\-\_OP\-\_stack\-\_value} &0x9f &0& \\
1218 \livetarg{chap:DWOPlouser}{DW\-\_OP\-\_lo\-\_user} &0xe0 && \\
1219 \livetarg{chap:DWOPhiuser}{DW\-\_OP\-\_hi\-\_user} &0xff && \\
1225 \subsection{Location Descriptions}
1226 \label{datarep:locationdescriptions}
1228 A location description is used to compute the
1229 location of a variable or other entity.
1231 \subsection{Location Lists}
1232 \label{datarep:locationlists}
1234 Each entry in a location list is either a location list entry,
1235 a base address selection entry, or an end of list entry.
1237 A location list entry consists of two address offsets followed
1238 by a 2\dash byte length, followed by a block of contiguous bytes
1239 that contains a DWARF location description. The length
1240 specifies the number of bytes in that block. The two offsets
1241 are the same size as an address on the target machine.
1243 A base address selection entry and an end of list entry each
1244 consist of two (constant or relocated) address offsets. The two
1245 offsets are the same size as an address on the target machine.
1247 For a location list to be specified, the base address of
1248 the corresponding compilation unit must be defined
1249 (see Section \refersec{chap:normalandpartialcompilationunitentries}).
1251 \section{Base Type Attribute Encodings}
1252 \label{datarep:basetypeattributeencodings}
1254 The encodings of the constants used in the \livelink{chap:DWATencoding}{DW\-\_AT\-\_encoding}
1255 attribute are given in
1256 Table \refersec{tab:basetypeencodingvalues}
1259 \setlength{\extrarowheight}{0.1cm}
1260 \begin{longtable}{l|c}
1261 \caption{Base type encoding values} \label{tab:basetypeencodingvalues} \\
1262 \hline \\ \bfseries Base type encoding code name&\bfseries Value \\ \hline
1264 \bfseries Base type encoding code name&\bfseries Value\\ \hline
1266 \hline \emph{Continued on next page}
1271 \livelink{chap:DWATEaddress}{DW\-\_ATE\-\_address}&0x01 \\
1272 \livelink{chap:DWATEboolean}{DW\-\_ATE\-\_boolean}&0x02 \\
1273 \livelink{chap:DWATEcomplexfloat}{DW\-\_ATE\-\_complex\-\_float}&0x03 \\
1274 \livelink{chap:DWATEfloat}{DW\-\_ATE\-\_float}&0x04 \\
1275 \livelink{chap:DWATEsigned}{DW\-\_ATE\-\_signed}&0x05 \\
1276 \livelink{chap:DWATEsignedchar}{DW\-\_ATE\-\_signed\-\_char}&0x06 \\
1277 \livelink{chap:DWATEunsigned}{DW\-\_ATE\-\_unsigned}&0x07 \\
1278 \livelink{chap:DWATEunsignedchar}{DW\-\_ATE\-\_unsigned\-\_char}&0x08 \\
1279 \livelink{chap:DWATEimaginaryfloat}{DW\-\_ATE\-\_imaginary\-\_float}&0x09 \\
1280 \livelink{chap:DWATEpackeddecimal}{DW\-\_ATE\-\_packed\-\_decimal}&0x0a \\
1281 \livelink{chap:DWATEnumericstring}{DW\-\_ATE\-\_numeric\-\_string}&0x0b \\
1282 \livelink{chap:DWATEedited}{DW\-\_ATE\-\_edited}&0x0c \\
1283 \livelink{chap:DWATEsignedfixed}{DW\-\_ATE\-\_signed\-\_fixed}&0x0d \\
1284 \livelink{chap:DWATEunsignedfixed}{DW\-\_ATE\-\_unsigned\-\_fixed}&0x0e \\
1285 \livelink{chap:DWATEdecimalfloat}{DW\-\_ATE\-\_decimal\-\_float} & 0x0f \\
1286 \livelink{chap:DWATEUTF}{DW\-\_ATE\-\_UTF} \ddag & 0x10 \\
1287 \livetarg{chap:DWATElouser}{DW\-\_ATE\-\_lo\-\_user} & 0x80 \\
1288 \livetarg{chap:DWATEhiuser}{DW\-\_ATE\-\_hi\-\_user} & 0xff \\
1291 \ddag Base type encoding new in DWARF Version 4
1295 The encodings of the constants used in the
1296 \livelink{chap:DWATdecimalsign}{DW\-\_AT\-\_decimal\-\_sign} attribute
1298 Table \refersec{tab:decimalsignencodings}.
1302 \setlength{\extrarowheight}{0.1cm}
1303 \begin{longtable}{l|c}
1304 \caption{Decimal sign encodings} \label{tab:decimalsignencodings} \\
1305 \hline \\ \bfseries Decimal sign code name&\bfseries Value \\ \hline
1307 \bfseries Decimal sign code name&\bfseries Value\\ \hline
1309 \hline \emph{Continued on next page}
1314 \livelink{chap:DWDSunsigned}{DW\-\_DS\-\_unsigned} & 0x01 \\
1315 \livelink{chap:DWDSleadingoverpunch}{DW\-\_DS\-\_leading\-\_overpunch} & 0x02 \\
1316 \livelink{chap:DWDStrailingoverpunch}{DW\-\_DS\-\_trailing\-\_overpunch} & 0x03 \\
1317 \livelink{chap:DWDSleadingseparate}{DW\-\_DS\-\_leading\-\_separate} & 0x04 \\
1318 \livelink{chap:DWDStrailingseparate}{DW\-\_DS\-\_trailing\-\_separate} & 0x05 \\
1323 The encodings of the constants used in the
1324 \livelink{chap:DWATendianity}{DW\-\_AT\-\_endianity} attribute are given in
1325 Table \refersec{tab:endianityencodings}.
1328 \setlength{\extrarowheight}{0.1cm}
1329 \begin{longtable}{l|c}
1330 \caption{Endianity encodings} \label{tab:endianityencodings}\\
1331 \hline \\ \bfseries Endian code name&\bfseries Value \\ \hline
1333 \bfseries Endian code name&\bfseries Value\\ \hline
1335 \hline \emph{Continued on next page}
1340 \livelink{chap:DWENDdefault}{DW\-\_END\-\_default} & 0x00 \\
1341 \livelink{chap:DWENDbig}{DW\-\_END\-\_big} & 0x01 \\
1342 \livelink{chap:DWENDlittle}{DW\-\_END\-\_little} & 0x02 \\
1343 \livetarg{chap:DWENDlouser}{DW\-\_END\-\_lo\-\_user} & 0x40 \\
1344 \livetarg{chap:DWENDhiuser}{DW\-\_END\-\_hi\-\_user} & 0xff \\
1349 \section{Accessibility Codes}
1350 \label{datarep:accessibilitycodes}
1351 The encodings of the constants used in the \livelink{chap:DWATaccessibility}{DW\-\_AT\-\_accessibility}
1352 attribute are given in
1353 Table \refersec{tab:accessibilityencodings}.
1356 \setlength{\extrarowheight}{0.1cm}
1357 \begin{longtable}{l|c}
1358 \caption{Accessibility encodings} \label{tab:accessibilityencodings}\\
1359 \hline \\ \bfseries Accessibility code name&\bfseries Value \\ \hline
1361 \bfseries Accessibility code name&\bfseries Value\\ \hline
1363 \hline \emph{Continued on next page}
1368 \livelink{chap:DWACCESSpublic}{DW\-\_ACCESS\-\_public}&0x01 \\
1369 \livelink{chap:DWACCESSprotected}{DW\-\_ACCESS\-\_protected}&0x02 \\
1370 \livelink{chap:DWACCESSprivate}{DW\-\_ACCESS\-\_private}&0x03 \\
1376 \section{Visibility Codes}
1377 \label{datarep:visibilitycodes}
1378 The encodings of the constants used in the
1379 \livelink{chap:DWATvisibility}{DW\-\_AT\-\_visibility} attribute are given in
1380 Table \refersec{tab:visibilityencodings}.
1383 \setlength{\extrarowheight}{0.1cm}
1384 \begin{longtable}{l|c}
1385 \caption{Visibility encodings} \label{tab:visibilityencodings}\\
1386 \hline \\ \bfseries Visiibility code name&\bfseries Value \\ \hline
1388 \bfseries Visibility code name&\bfseries Value\\ \hline
1390 \hline \emph{Continued on next page}
1395 \livelink{chap:DWVISlocal}{DW\-\_VIS\-\_local}&0x01 \\
1396 \livelink{chap:DWVISexported}{DW\-\_VIS\-\_exported}&0x02 \\
1397 \livelink{chap:DWVISqualified}{DW\-\_VIS\-\_qualified}&0x03 \\
1402 \section{Virtuality Codes}
1403 \label{datarep:vitualitycodes}
1405 The encodings of the constants used in the
1406 \livelink{chap:DWATvirtuality}{DW\-\_AT\-\_virtuality} attribute are given in
1407 Table \refersec{tab:virtualityencodings}.
1410 \setlength{\extrarowheight}{0.1cm}
1411 \begin{longtable}{l|c}
1412 \caption{Virtuality encodings} \label{tab:virtualityencodings}\\
1413 \hline \\ \bfseries Virtuality code name&\bfseries Value \\ \hline
1415 \bfseries Virtuality code name&\bfseries Value\\ \hline
1417 \hline \emph{Continued on next page}
1422 \livelink{chap:DWVIRTUALITYnone}{DW\-\_VIRTUALITY\-\_none}&0x00 \\
1423 \livelink{chap:DWVIRTUALITYvirtual}{DW\-\_VIRTUALITY\-\_virtual}&0x01 \\
1424 \livelink{chap:DWVIRTUALITYpurevirtual}{DW\-\_VIRTUALITY\-\_pure\-\_virtual}&0x02 \\
1432 \livelink{chap:DWVIRTUALITYnone}{DW\-\_VIRTUALITY\-\_none} is equivalent to the absence of the
1433 \livelink{chap:DWATvirtuality}{DW\-\_AT\-\_virtuality}
1436 \section{Source Languages}
1437 \label{datarep:sourcelanguages}
1439 The encodings of the constants used in the \livelink{chap:DWATlanguage}{DW\-\_AT\-\_language}
1440 attribute are given in
1441 Table \refersec{tab:languageencodings}.
1443 % If we don't force a following space it looks odd
1445 and their associated values are reserved, but the
1446 languages they represent are not well supported.
1447 Table \refersec{tab:languageencodings}
1448 also shows the default lower bound, if any, assumed for
1449 an omitted \livelink{chap:DWATlowerbound}{DW\-\_AT\-\_lower\-\_bound} attribute in the context of a
1450 \livelink{chap:DWTAGsubrangetype}{DW\-\_TAG\-\_subrange\-\_type} debugging information entry for each
1454 \setlength{\extrarowheight}{0.1cm}
1455 \begin{longtable}{l|c|c}
1456 \caption{Language encodings} \label{tab:languageencodings}\\
1457 \hline \\ \bfseries Language name&\bfseries Value &\bfseries Default Lower Bound \\ \hline
1459 \bfseries Language name&\bfseries Value &\bfseries Default Lower Bound\\ \hline
1461 \hline \emph{Continued on next page}
1466 \livelink{chap:DWLANGC89}{DW\-\_LANG\-\_C89}&0x0001&0 \\
1467 \livelink{chap:DWLANGC}{DW\-\_LANG\-\_C}&0x0002&0 \\
1468 \livelink{chap:DWLANGAda83}{DW\-\_LANG\-\_Ada83} \dag &0x0003&1 \\
1469 \livelink{chap:DWLANGCplusplus}{DW\-\_LANG\-\_C\-\_plus\-\_plus} &0x0004&0 \\
1470 \livelink{chap:DWLANGCobol74}{DW\-\_LANG\-\_Cobol74} \dag &0x0005&1 \\
1471 \livelink{chap:DWLANGCobol85}{DW\-\_LANG\-\_Cobol85} \dag &0x0006&1 \\
1472 \livelink{chap:DWLANGFortran77}{DW\-\_LANG\-\_Fortran77}&0x0007&1 \\
1473 \livelink{chap:DWLANGFortran90}{DW\-\_LANG\-\_Fortran90}&0x0008&1 \\
1474 \livelink{chap:DWLANGPascal83}{DW\-\_LANG\-\_Pascal83}&0x0009&1 \\
1475 \livelink{chap:DWLANGModula2}{DW\-\_LANG\-\_Modula2}&0x000a&1 \\
1476 \livelink{chap:DWLANGJava}{DW\-\_LANG\-\_Java}&0x000b&0 \\
1477 \livelink{chap:DWLANGC99}{DW\-\_LANG\-\_C99}&0x000c&0 \\
1478 \livelink{chap:DWLANGAda95}{DW\-\_LANG\-\_Ada95} \dag &0x000d&1 \\
1479 \livelink{chap:DWLANGFortran95}{DW\-\_LANG\-\_Fortran95} &0x000e&1 \\
1480 \livelink{chap:DWLANGPLI}{DW\-\_LANG\-\_PLI} \dag &0x000f&1 \\
1481 \livelink{chap:DWLANGObjC}{DW\-\_LANG\-\_ObjC}&0x0010&0 \\
1482 \livelink{chap:DWLANGObjCplusplus}{DW\-\_LANG\-\_ObjC\-\_plus\-\_plus}&0x0011&0 \\
1483 \livelink{chap:DWLANGUPC}{DW\-\_LANG\-\_UPC}&0x0012&0 \\
1484 \livelink{chap:DWLANGD}{DW\-\_LANG\-\_D}&0x0013&0 \\
1485 \livelink{chap:DWLANGPython}{DW\-\_LANG\-\_Python} \dag &0x0014&0 \\
1486 \livetarg{chap:DWLANGlouser}{DW\-\_LANG\-\_lo\-\_user}&0x8000 & \\
1487 \livetarg{chap:DWLANGhiuser}{DW\-\_LANG\-\_hi\-\_user}&0xffff & \\
1493 \section{Address Class Encodings}
1494 \label{datarep:addressclassencodings}
1496 The value of the common address class encoding
1497 \livelink{chap:DWADDRnone}{DW\-\_ADDR\-\_none} is 0.
1500 \section{Identifier Case}
1501 \label{datarep:identifiercase}
1503 The encodings of the constants used in the
1504 \livelink{chap:DWATidentifiercase}{DW\-\_AT\-\_identifier\-\_case} attribute are given in
1505 Table \refersec{tab:identifiercaseencodings}.
1508 \setlength{\extrarowheight}{0.1cm}
1509 \begin{longtable}{l|c}
1510 \caption{Identifier case encodings} \label{tab:identifiercaseencodings}\\
1511 \hline \\ \bfseries Identifier case name&\bfseries Value \\ \hline
1513 \bfseries Identifier case name&\bfseries Value\\ \hline
1515 \hline \emph{Continued on next page}
1519 \livelink{chap:DWIDcasesensitive}{DW\-\_ID\-\_case\-\_sensitive}&0x00 \\
1520 \livelink{chap:DWIDupcase}{DW\-\_ID\-\_up\-\_case}&0x01 \\
1521 \livelink{chap:DWIDdowncase}{DW\-\_ID\-\_down\-\_case}&0x02 \\
1522 \livelink{chap:DWIDcaseinsensitive}{DW\-\_ID\-\_case\-\_insensitive}&0x03 \\
1526 \section{Calling Convention Encodings}
1527 \label{datarep:callingconventionencodings}
1528 The encodings of the constants used in the
1529 \livelink{chap:DWATcallingconvention}{DW\-\_AT\-\_calling\-\_convention} attribute are given in
1530 Table \refersec{tab:callingconventionencodings}.
1533 \setlength{\extrarowheight}{0.1cm}
1534 \begin{longtable}{l|c}
1535 \caption{Calling convention encodings} \label{tab:callingconventionencodings}\\
1536 \hline \\ \bfseries Calling Convention name&\bfseries Value \\ \hline
1538 \bfseries Calling Convention name&\bfseries Value\\ \hline
1540 \hline \emph{Continued on next page}
1545 \livelink{chap:DWCCnormal}{DW\-\_CC\-\_normal}&0x01 \\
1546 \livelink{chap:DWCCprogram}{DW\-\_CC\-\_program}&0x02 \\
1547 \livelink{chap:DWCCnocall}{DW\-\_CC\-\_nocall}&0x03 \\
1548 \livetarg{chap:DWCClouser}{DW\-\_CC\-\_lo\-\_user}&0x40 \\
1549 \livetarg{chap:DWCChiuser}{DW\-\_CC\-\_hi\-\_user}&0xff \\
1554 \section{Inline Codes}
1555 \label{datarep:inlinecodes}
1557 The encodings of the constants used in the
1558 \livelink{chap:DWATinline}{DW\-\_AT\-\_inline} attribute are given in
1559 Table \refersec{tab:inlineencodings}.
1562 \setlength{\extrarowheight}{0.1cm}
1563 \begin{longtable}{l|c}
1564 \caption{Inline encodings} \label{tab:inlineencodings}\\
1565 \hline \\ \bfseries Iline Code name&\bfseries Value \\ \hline
1567 \bfseries Iline Code name&\bfseries Value\\ \hline
1569 \hline \emph{Continued on next page}
1574 \livelink{chap:DWINLnotinlined}{DW\-\_INL\-\_not\-\_inlined}&0x00 \\
1575 \livelink{chap:DWINLinlined}{DW\-\_INL\-\_inlined}&0x01 \\
1576 \livelink{chap:DWINLdeclarednotinlined}{DW\-\_INL\-\_declared\-\_not\-\_inlined}&0x02 \\
1577 \livelink{chap:DWINLdeclaredinlined}{DW\-\_INL\-\_declared\-\_inlined}&0x03 \\
1582 % this clearpage is ugly, but the following table came
1583 % out oddly without it.
1585 \section{Array Ordering}
1586 \label{datarep:arrayordering}
1588 The encodings of the constants used in the
1589 \livelink{chap:DWATordering}{DW\-\_AT\-\_ordering} attribute are given in
1590 Table \refersec{tab:orderingencodings}.
1593 \setlength{\extrarowheight}{0.1cm}
1594 \begin{longtable}{l|c}
1595 \caption{Ordering encodings} \label{tab:orderingencodings}\\
1596 \hline \\ \bfseries Ordering name&\bfseries Value \\ \hline
1598 \bfseries Ordering name&\bfseries Value\\ \hline
1600 \hline \emph{Continued on next page}
1605 \livelink{chap:DWORDrowmajor}{DW\-\_ORD\-\_row\-\_major}&0x00 \\
1606 \livelink{chap:DWORDcolmajor}{DW\-\_ORD\-\_col\-\_major}&0x01 \\
1612 \section{Discriminant Lists}
1613 \label{datarep:discriminantlists}
1615 The descriptors used in the
1616 \livelink{chap:DWATdiscrlist}{DW\-\_AT\-\_discr\-\_list} attribute are
1617 encoded as 1\dash byte constants. The
1618 defined values are given in
1619 Table \refersec{tab:discriminantdescriptorencodings}.
1621 % Odd that the 'Name' field captalized here, it is not caps elsewhere.
1623 \setlength{\extrarowheight}{0.1cm}
1624 \begin{longtable}{l|c}
1625 \caption{Discriminant descriptor encodings} \label{tab:discriminantdescriptorencodings}\\
1626 \hline \\ \bfseries Descriptor Name&\bfseries Value \\ \hline
1628 \bfseries Descriptor Name&\bfseries Value\\ \hline
1630 \hline \emph{Continued on next page}
1635 \livetarg{chap:DWDSClabel}{DW\-\_DSC\-\_label}&0x00 \\
1636 \livetarg{chap:DWDSCrange}{DW\-\_DSC\-\_range}&0x01 \\
1641 \section{Name Lookup Tables}
1642 \label{datarep:namelookuptables}
1644 Each set of entries in the table of global names contained
1645 in the .debug\_pubnames and .debug\_pubtypes sections begins
1646 with a header consisting of:
1649 \begin{enumerate}[1.]
1650 \item unit\_length (initial length) \\
1651 A 4\dash byte or 12\dash byte unsigned integer representing the length
1652 of the .debug\_info contribution for that compilation unit,
1653 not including the length field itself. In the 32\dash bit DWARF
1654 format, this is a 4\dash byte unsigned integer (which must be less
1655 than 0xfffffff0); in the 64\dash bit DWARF format, this consists
1656 of the 4\dash byte value 0xffffffff followed by an 8\dash byte unsigned
1657 integer that gives the actual length
1658 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
1660 \item version (uhalf)
1661 A 2\dash byte unsigned integer representing the version of the
1662 DWARF information for the compilation unit
1663 (see Appendix \refersec{app:dwarfsectionversionnumbersinformative}).
1664 The value in this field is 4.
1666 % Some say unsigned offset this just says offset: FIXME
1667 \item debug\_info\_offset (section offset) \\
1668 A 4\dash byte or 8\dash byte offset into the .debug\_info
1669 section of the compilation unit header.
1671 the 32\dash bit DWARF format, this is a 4\dash byte unsigned offset;
1672 in the 64\dash bit DWARF format, this is an 8\dash byte unsigned offsets
1673 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
1675 \item debug\_info\_length (section length) \\
1676 A 4\dash byte or 8\dash byte length containing the size in bytes of the
1677 contents of the .debug\_info section generated to represent
1678 this compilation unit. In the 32\dash bit DWARF format, this is
1679 a 4\dash byte unsigned length; in the 64\dash bit DWARF format, this
1680 is an 8-byte unsigned length
1681 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
1686 This header is followed by a series of tuples. Each tuple
1687 consists of a 4\dash byte or 8\dash byte offset followed by a string
1688 of non\dash null bytes terminated by one null byte.
1690 DWARF format, this is a 4\dash byte offset; in the 64\dash bit DWARF
1691 format, it is an 8\dash byte offset.
1692 Each set is terminated by an
1693 offset containing the value 0.
1696 \section{Address Range Table}
1697 \label{datarep:addrssrangetable}
1699 Each set of entries in the table of address ranges contained
1700 in the .debug\_aranges section begins with a header containing:
1702 \begin{enumerate}[1.]
1703 % FIXME The unit length text is not fully consistent across
1706 \item unit\_length (initial length) \\
1707 A 4-byte or 12-byte length containing the length of the
1708 set of entries for this compilation unit, not including the
1709 length field itself. In the 32-bit DWARF format, this is a
1710 4-byte unsigned integer (which must be less than 0xfffffff0);
1711 in the 64-bit DWARF format, this consists of the 4-byte value
1712 0xffffffff followed by an 8-byte unsigned integer that gives
1714 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
1716 \item version (uhalf) \\
1717 A 2\dash byte version identifier containing the value 2
1718 (see Appendix \refersec{app:dwarfsectionversionnumbersinformative}).
1720 \item debug\_info\_offset (section offset) \\
1721 A 4\dash byte or 8\dash byte offset into the .debug\_info section of
1722 the compilation unit header. In the 32\dash bit DWARF format,
1723 this is a 4\dash byte unsigned offset; in the 64\dash bit DWARF format,
1724 this is an 8\dash byte unsigned offset
1725 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
1727 \item address\_size (ubyte) \\
1728 A 1\dash byte unsigned integer containing the size in bytes of an
1729 address (or the offset portion of an address for segmented
1730 addressing) on the target system.
1732 \item segment\_size (ubyte) \\
1733 A 1\dash byte unsigned integer containing the size in bytes of a
1734 segment selector on the target system.
1738 This header is followed by a series of tuples. Each tuple
1739 consists of a segment, an address and a length.
1741 size is given by the segment\_size field of the header; the
1742 address and length size are each given by the address\_size
1743 field of the header.
1744 The first tuple following the header in
1745 each set begins at an offset that is a multiple of the size
1746 of a single tuple (that is, the size of a segment selector
1747 plus twice the size of an address).
1748 The header is padded, if
1749 necessary, to that boundary. Each set of tuples is terminated
1750 by a 0 for the segment, a 0 for the address and 0 for the
1751 length. If the segment\_size field in the header is zero,
1752 the segment selectors are omitted from all tuples, including
1753 the terminating tuple.
1756 \section{Line Number Information}
1757 \label{datarep:linenumberinformation}
1759 The version number in the line number program header is 4
1760 (see Appendix \refersec{app:dwarfsectionversionnumbersinformative}).
1762 The boolean values ``true'' and ``false''
1763 used by the line number information program are encoded
1764 as a single byte containing the value 0
1765 for ``false,'' and a non-zero value for ``true.''
1767 The encodings for the standard opcodes are given in
1768 Table \refersec{tab:linenumberstandardopcodeencodings}.
1770 % Odd that the 'Name' field captalized here, it is not caps elsewhere.
1772 \setlength{\extrarowheight}{0.1cm}
1773 \begin{longtable}{l|c}
1774 \caption{Line Number Standard Opcode encodings} \label{tab:linenumberstandardopcodeencodings}\\
1775 \hline \\ \bfseries Opcode Name&\bfseries Value \\ \hline
1777 \bfseries Opcode Name&\bfseries Value\\ \hline
1779 \hline \emph{Continued on next page}
1784 \livelink{chap:DWLNScopy}{DW\-\_LNS\-\_copy}&0x01 \\
1785 \livelink{chap:DWLNSadvancepc}{DW\-\_LNS\-\_advance\-\_pc}&0x02 \\
1786 \livelink{chap:DWLNSadvanceline}{DW\-\_LNS\-\_advance\-\_line}&0x03 \\
1787 \livelink{chap:DWLNSsetfile}{DW\-\_LNS\-\_set\-\_file}&0x04 \\
1788 \livelink{chap:DWLNSsetcolumn}{DW\-\_LNS\-\_set\-\_column}&0x05 \\
1789 \livelink{chap:DWLNSnegatestmt}{DW\-\_LNS\-\_negate\-\_stmt}&0x06 \\
1790 \livelink{chap:DWLNSsetbasicblock}{DW\-\_LNS\-\_set\-\_basic\-\_block}&0x07 \\
1791 \livelink{chap:DWLNSconstaddpc}{DW\-\_LNS\-\_const\-\_add\-\_pc}*0x08 \\
1792 \livelink{chap:DWLNSfixedadvancepc}{DW\-\_LNS\-\_fixed\-\_advance\-\_pc}&0x09 \\
1793 \livelink{chap:DWLNSsetprologueend}{DW\-\_LNS\-\_set\-\_prologue\-\_end}&0x0a \\
1794 \livelink{chap:DWLNSsetepiloguebegin}{DW\-\_LNS\-\_set\-\_epilogue\-\_begin}&0x0b \\
1795 \livelink{chap:DWLNSsetisa}{DW\-\_LNS\-\_set\-\_isa}&0x0c \\
1801 The encodings for the extended opcodes are given in
1802 Table \refersec{tab:linenumberextendedopcodeencodings}.
1805 \setlength{\extrarowheight}{0.1cm}
1806 \begin{longtable}{l|c}
1807 \caption{Line Number Extended Opcode encodings} \label{tab:linenumberextendedopcodeencodings}\\
1808 \hline \\ \bfseries Opcode Name&\bfseries Value \\ \hline
1810 \bfseries Opcode Name&\bfseries Value\\ \hline
1812 \hline \emph{Continued on next page}
1817 \livelink{chap:DWLNEendsequence}{DW\-\_LNE\-\_end\-\_sequence}&0x01 \\
1818 \livelink{chap:DWLNEsetaddress}{DW\-\_LNE\-\_set\-\_address}&0x02\\
1819 \livelink{chap:DWLNEdefinefile}{DW\-\_LNE\-\_define\-\_file}&0x03\\
1820 \livelink{chap:DWLNEsetdiscriminator}{DW\-\_LNE\-\_set\-\_discriminator} \ddag &0x04 \\
1821 \livetarg{chap:DWLNElouser}{DW\-\_LNE\-\_lo\-\_user}&0x80 \\
1822 \livetarg{chap:DWLNEhiuser}{DW\-\_LNE\-\_hi\-\_user}&0xff \\
1825 \ddag Extended opcode new in DWARF Version 4.
1828 \section{Macro Information}
1829 \label{datarep:macroinformation}
1831 The source line numbers and source file indices encoded in the
1832 macro information section are represented as unsigned LEB128
1833 numbers as are the constants in a \livelink{chap:DWMACINFOvendorext}{DW\-\_MACINFO\-\_vendor\-\_ext} entry.
1835 The macinfo type is encoded as a single byte.
1836 The encodings are given in
1837 Table \refersec{tab:macinfotypeencodings}.
1841 \setlength{\extrarowheight}{0.1cm}
1842 \begin{longtable}{l|c}
1843 \caption{Macinfo Type Encodings} \label{tab:macinfotypeencodings}\\
1844 \hline \\ \bfseries Macinfo Type Name&\bfseries Value \\ \hline
1846 \bfseries Macinfo Type Name&\bfseries Value\\ \hline
1848 \hline \emph{Continued on next page}
1853 \livelink{chap:DWMACINFOdefine}{DW\-\_MACINFO\-\_define}&0x01 \\
1854 \livelink{chap:DWMACINFOundef}{DW\-\_MACINFO\-\_undef}&0x02 \\
1855 \livelink{chap:DWMACINFOstartfile}{DW\-\_MACINFO\-\_start\-\_file}&0x03 \\
1856 \livelink{chap:DWMACINFOendfile}{DW\-\_MACINFO\-\_end\-\_file}&0x04 \\
1857 \livelink{chap:DWMACINFOvendorext}{DW\-\_MACINFO\-\_vendor\-\_ext}&0xff \\
1862 \section{Call Frame Information}
1863 \label{datarep:callframeinformation}
1865 In the 32\dash bit DWARF format, the value of the CIE id in the
1866 CIE header is 0xffffffff; in the 64\dash bit DWARF format, the
1867 value is 0xffffffffffffffff.
1869 The value of the CIE version number is 4
1870 (see Appendix \refersec{app:dwarfsectionversionnumbersinformative}).
1872 Call frame instructions are encoded in one or more bytes. The
1873 primary opcode is encoded in the high order two bits of
1874 the first byte (that is, opcode = byte >> 6). An operand
1875 or extended opcode may be encoded in the low order 6
1876 bits. Additional operands are encoded in subsequent bytes.
1877 The instructions and their encodings are presented in
1878 Table \refersec{tab:callframeinstructionencodings}.
1881 \setlength{\extrarowheight}{0.1cm}
1882 \begin{longtable}{l|c|c|l|l}
1883 \caption{Call frame instruction encodings} \label{tab:callframeinstructionencodings} \\
1884 \hline \\ &\bfseries High 2 &\bfseries Low 6 & & \\
1885 \bfseries Instruction&\bfseries Bits &\bfseries Bits &\bfseries Operand 1 &\bfseries Operand 2\\ \hline
1887 & \bfseries High 2 &\bfseries Low 6 & &\\
1888 \bfseries Instruction&\bfseries Bits &\bfseries Bits &\bfseries Operand 1 &\bfseries Operand 2\\ \hline
1890 \hline \emph{Continued on next page}
1895 \livelink{chap:DWCFAadvanceloc}{DW\-\_CFA\-\_advance\-\_loc}&0x1&delta & \\
1896 \livelink{chap:DWCFAoffset}{DW\-\_CFA\-\_offset}&0x2®ister&ULEB128 offset \\
1897 \livelink{chap:DWCFArestore}{DW\-\_CFA\-\_restore}&0x3®ister & & \\
1898 \livelink{chap:DWCFAnop}{DW\-\_CFA\-\_nop}&0&0 & & \\
1899 \livelink{chap:DWCFAsetloc}{DW\-\_CFA\-\_set\-\_loc}&0&0x01&address & \\
1900 \livelink{chap:DWCFAadvanceloc1}{DW\-\_CFA\-\_advance\-\_loc1}&0&0x02&1\dash byte delta & \\
1901 \livelink{chap:DWCFAadvanceloc2}{DW\-\_CFA\-\_advance\-\_loc2}&0&0x03&2\dash byte delta & \\
1902 \livelink{chap:DWCFAadvanceloc4}{DW\-\_CFA\-\_advance\-\_loc4}&0&0x04&4\dash byte delta & \\
1903 \livelink{chap:DWCFAoffsetextended}{DW\-\_CFA\-\_offset\-\_extended}&0&0x05&ULEB128 register&ULEB128 offset \\
1904 \livelink{chap:DWCFArestoreextended}{DW\-\_CFA\-\_restore\-\_extended}&0&0x06&ULEB128 register & \\
1905 \livelink{chap:DWCFAundefined}{DW\-\_CFA\-\_undefined}&0&0x07&ULEB128 register & \\
1906 \livelink{chap:DWCFAsamevalue}{DW\-\_CFA\-\_same\-\_value}&0&0x08 &ULEB128 register & \\
1907 \livelink{chap:DWCFAregister}{DW\-\_CFA\-\_register}&0&0x09&ULEB128 register &ULEB128 offset \\
1908 \livelink{chap:DWCFArememberstate}{DW\-\_CFA\-\_remember\-\_state}&0&0x0a & & \\
1909 \livelink{chap:DWCFArestorestate}{DW\-\_CFA\-\_restore\-\_state}&0&0x0b & & \\
1910 \livelink{chap:DWCFAdefcfa}{DW\-\_CFA\-\_def\-\_cfa}&0&0x0c &ULEB128 register&ULEB128 offset \\
1911 \livelink{chap:DWCFAdefcfaregister}{DW\-\_CFA\-\_def\-\_cfa\-\_register}&0&0x0d&ULEB128 register & \\
1912 \livelink{chap:DWCFAdefcfaoffset}{DW\-\_CFA\-\_def\-\_cfa\-\_offset}&0&0x0e &ULEB128 offset & \\
1913 \livelink{chap:DWCFAdefcfaexpression}{DW\-\_CFA\-\_def\-\_cfa\-\_expression}&0&0x0f &BLOCK \\
1914 \livelink{chap:DWCFAexpression}{DW\-\_CFA\-\_expression}&0&0x10&ULEB128 register & BLOCK \\
1916 \livelink{chap:DWCFAoffsetextendedsf}{DW\-\_CFA\-\_offset\-\_extended\-\_sf}&0&0x11&ULEB128 register&SLEB128 offset \\
1917 \livelink{chap:DWCFAdefcfasf}{DW\-\_CFA\-\_def\-\_cfa\-\_sf}&0&0x12&ULEB128 register&SLEB128 offset \\
1918 \livelink{chap:DWCFAdefcfaoffsetsf}{DW\-\_CFA\-\_def\-\_cfa\-\_offset\-\_sf}&0&0x13&SLEB128 offset & \\
1919 \livelink{chap:DWCFAvaloffset}{DW\-\_CFA\-\_val\-\_offset}&0&0x14&ULEB128&ULEB128 \\
1920 \livelink{chap:DWCFAvaloffsetsf}{DW\-\_CFA\-\_val\-\_offset\-\_sf}&0&0x15&ULEB128&SLEB128 \\
1921 \livelink{chap:DWCFAvalexpression}{DW\-\_CFA\-\_val\-\_expression}&0&0x16&ULEB128&BLOCK \\
1922 \livetarg{chap:DWCFAlouser}{DW\-\_CFA\-\_lo\-\_user}&0&0x1c & & \\
1923 \livetarg{chap:DWCFAhiuser}{DW\-\_CFA\-\_hi\-\_user}&0&0x3f & & \\
1927 \section{Non-continguous Address Ranges}
1928 \label{datarep:noncontiguousaddressranges}
1930 Each entry in a range list
1931 (see Section \refersec{chap:noncontiguousaddressranges})
1933 range list entry, a base address selection entry, or an end
1936 A range list entry consists of two relative addresses. The
1937 addresses are the same size as addresses on the target machine.
1939 A base address selection entry and an end of list entry each
1940 consist of two (constant or relocated) addresses. The two
1941 addresses are the same size as addresses on the target machine.
1943 For a range list to be specified, the base address of the
1944 corresponding compilation unit must be defined
1945 (see Section \refersec{chap:normalandpartialcompilationunitentries}).
1948 \section{Dependencies and Constraints}
1949 \label{datarep:dependenciesandconstraints}
1951 The debugging information in this format is intended to
1952 exist in the .debug\_abbrev, .debug\_aranges, .debug\_frame,
1953 .debug\_info, .debug\_line, .debug\_loc, .debug\_macinfo,
1954 .debug\_pubnames, .debug\_pubtypes, .debug\_ranges, .debug\_str
1955 and .debug\_types sections of an object file, or equivalent
1956 separate file or database. The information is not
1957 word\dash aligned. Consequently: •
1960 \item For the 32\dash bit DWARF format and a target architecture with
1961 32\dash bit addresses, an assembler or compiler must provide a way
1962 to produce 2\dash byte and 4\dash byte quantities without alignment
1963 restrictions, and the linker must be able to relocate a
1964 4\dash byte address or section offset that occurs at an arbitrary
1967 \item For the 32\dash bit DWARF format and a target architecture with
1968 64\dash bit addresses, an assembler or compiler must provide a
1969 way to produce 2\dash byte, 4\dash byte and 8\dash byte quantities without
1970 alignment restrictions, and the linker must be able to relocate
1971 an 8\dash byte address or 4\dash byte section offset that occurs at an
1972 arbitrary alignment.
1974 \item For the 64\dash bit DWARF format and a target architecture with
1975 32\dash bit addresses, an assembler or compiler must provide a
1976 way to produce 2\dash byte, 4\dash byte and 8\dash byte quantities without
1977 alignment restrictions, and the linker must be able to relocate
1978 a 4\dash byte address or 8\dash byte section offset that occurs at an
1979 arbitrary alignment.
1981 \textit{It is expected that this will be required only for very large
1982 32\dash bit programs or by those architectures which support
1983 a mix of 32\dash bit and 64\dash bit code and data within the same
1986 \item For the 64\dash bit DWARF format and a target architecture with
1987 64\dash bit addresses, an assembler or compiler must provide a
1988 way to produce 2\dash byte, 4\dash byte and 8\dash byte quantities without
1989 alignment restrictions, and the linker must be able to
1990 relocate an 8\dash byte address or section offset that occurs at
1991 an arbitrary alignment.
1994 \section{Integer Representation Names}
1995 \label{datarep:integerrepresentationnames}
1997 The sizes of the integers used in the lookup by name, lookup
1998 by address, line number and call frame information sections
2000 Table 41 \refersec{tab:integerrepresentationnames}.
2003 \setlength{\extrarowheight}{0.1cm}
2004 \begin{longtable}{c|l}
2005 \caption{Integer Representation Names} \label{tab:integerrepresentationnames}\\
2006 \hline \\ \bfseries Representation Name&\bfseries Representation \\ \hline
2008 \bfseries Representation Name&\bfseries Representation\\ \hline
2010 \hline \emph{Continued on next page}
2015 sbyte& signed, 1\dash byte integer \\
2016 ubyte&unsigned, 1\dash byte integer \\
2017 uhalf&unsigned, 2\dash byte integer \\
2018 uword&unsigned, 4\dash byte integer \\
2023 \section{Type Signature Computation}
2024 \label{datarep:typesignaturecomputation}
2026 A type signature is computed only by the DWARF producer;
2027 it is used by a DWARF consumer to resolve type references to
2028 the type definitions that are contained in type units.
2030 The type signature for a type T0 is formed from the MD5
2031 hash of a flattened description of the type. The flattened
2032 description of the type is a byte sequence derived from the
2033 DWARF encoding of the type as follows:
2035 \begin{enumerate}[1.]
2037 \item Start with an empty sequence S and a list V of visited
2038 types, where V is initialized to a list containing the type
2039 T0 as its single element. Elements in V are indexed from 1,
2042 \item If the debugging information entry represents a type that
2043 is nested inside another type or a namespace, append to S
2044 the type’s context as follows: For each surrounding type
2045 or namespace, beginning with the outermost such construct,
2046 append the letter 'C', the DWARF tag of the construct, and
2047 the name (taken from the \livelink{chap:DWATname}{DW\-\_AT\-\_name} attribute) of the type
2048 or namespace (including its trailing null byte).
2050 \item Append to S the letter 'D', followed by the DWARF tag of
2051 the debugging information entry.
2053 \item For each of the following attributes that are present in
2054 the debugging information entry, in the order listed below,
2055 append to S a marker letter (see below), the DWARF attribute
2056 code, and the attribute value.
2059 \item \livelink{chap:DWATname}{DW\-\_AT\-\_name}
2060 \item \livelink{chap:DWATaccessibility}{DW\-\_AT\-\_accessibility}
2061 \item \livelink{chap:DWATaddressclass}{DW\-\_AT\-\_address\-\_class}
2062 \item \livelink{chap:DWATallocated}{DW\-\_AT\-\_allocated}
2063 \item \livelink{chap:DWATartificial}{DW\-\_AT\-\_artificial}
2064 \item \livelink{chap:DWATassociated}{DW\-\_AT\-\_associated}
2065 \item \livelink{chap:DWATbinaryscale}{DW\-\_AT\-\_binary\-\_scale}
2066 \item \livelink{chap:DWATbitoffset}{DW\-\_AT\-\_bit\-\_offset}
2067 \item \livelink{chap:DWATbitsize}{DW\-\_AT\-\_bit\-\_size}
2068 \item \livelink{chap:DWATbitstride}{DW\-\_AT\-\_bit\-\_stride}
2069 \item \livelink{chap:DWATbytesize}{DW\-\_AT\-\_byte\-\_size}
2070 \item \livelink{chap:DWATbytestride}{DW\-\_AT\-\_byte\-\_stride}
2071 \item \livelink{chap:DWATconstexpr}{DW\-\_AT\-\_const\-\_expr}
2072 \item \livelink{chap:DWATconstvalue}{DW\-\_AT\-\_const\-\_value}
2073 \item \livelink{chap:DWATcontainingtype}{DW\-\_AT\-\_containing\-\_type}
2074 \item \livelink{chap:DWATcount}{DW\-\_AT\-\_count}
2075 \item \livelink{chap:DWATdatabitoffset}{DW\-\_AT\-\_data\-\_bit\-\_offset}
2076 \item \livelink{chap:DWATdatalocation}{DW\-\_AT\-\_data\-\_location}
2077 \item \livelink{chap:DWATdatamemberlocation}{DW\-\_AT\-\_data\-\_member\-\_location}
2078 \item \livelink{chap:DWATdecimalscale}{DW\-\_AT\-\_decimal\-\_scale}
2079 \item \livelink{chap:DWATdecimalsign}{DW\-\_AT\-\_decimal\-\_sign}
2080 \item \livelink{chap:DWATdefaultvalue}{DW\-\_AT\-\_default\-\_value}
2081 \item \livelink{chap:DWATdigitcount}{DW\-\_AT\-\_digit\-\_count}
2082 \item \livelink{chap:DWATdiscr}{DW\-\_AT\-\_discr}
2083 \item \livelink{chap:DWATdiscrlist}{DW\-\_AT\-\_discr\-\_list}
2084 \item \livelink{chap:DWATdiscrvalue}{DW\-\_AT\-\_discr\-\_value}
2085 \item \livelink{chap:DWATencoding}{DW\-\_AT\-\_encoding}
2086 \item \livelink{chap:DWATenumclass}{DW\-\_AT\-\_enum\-\_class}
2087 \item \livelink{chap:DWATendianity}{DW\-\_AT\-\_endianity}
2088 \item \livelink{chap:DWATexplicit}{DW\-\_AT\-\_explicit}
2089 \item \livelink{chap:DWATisoptional}{DW\-\_AT\-\_is\-\_optional}
2090 \item \livelink{chap:DWATlocation}{DW\-\_AT\-\_location}
2091 \item \livelink{chap:DWATlowerbound}{DW\-\_AT\-\_lower\-\_bound}
2092 \item \livelink{chap:DWATmutable}{DW\-\_AT\-\_mutable}
2093 \item \livelink{chap:DWATordering}{DW\-\_AT\-\_ordering}
2094 \item \livelink{chap:DWATpicturestring}{DW\-\_AT\-\_picture\-\_string}
2095 \item \livelink{chap:DWATprototyped}{DW\-\_AT\-\_prototyped}
2096 \item \livelink{chap:DWATsmall}{DW\-\_AT\-\_small}
2097 \item \livelink{chap:DWATsegment}{DW\-\_AT\-\_segment}
2098 \item \livelink{chap:DWATstringlength}{DW\-\_AT\-\_string\-\_length}
2099 \item \livelink{chap:DWATthreadsscaled}{DW\-\_AT\-\_threads\-\_scaled}
2100 \item \livelink{chap:DWATupperbound}{DW\-\_AT\-\_upper\-\_bound}
2101 \item \livelink{chap:DWATuselocation}{DW\-\_AT\-\_use\-\_location}
2102 \item \livelink{chap:DWATuseUTF8}{DW\-\_AT\-\_use\-\_UTF8}
2103 \item \livelink{chap:DWATvariableparameter}{DW\-\_AT\-\_variable\-\_parameter}
2104 \item \livelink{chap:DWATvirtuality}{DW\-\_AT\-\_virtuality}
2105 \item \livelink{chap:DWATvisibility}{DW\-\_AT\-\_visibility}
2106 \item \livelink{chap:DWATvtableelemlocation}{DW\-\_AT\-\_vtable\-\_elem\-\_location}
2109 Note that except for the initial \livelink{chap:DWATname}{DW\-\_AT\-\_name} attribute,
2110 attributes are appended in order according to the alphabetical
2111 spelling of their identifier.
2113 If an implementation defines any vendor-specific attributes,
2114 any such attributes that are essential to the definition of
2115 the type should also be included at the end of the above list,
2116 in their own alphabetical suborder.
2118 An attribute that refers to another type entry T is processed
2119 as follows: (a) If T is in the list V at some V[x], use the
2120 letter 'R' as the marker and use the unsigned LEB128 encoding
2121 of x as the attribute value; otherwise, (b) use the letter 'T'
2122 as the marker, process the type T recursively by performing
2123 Steps 2 through 7, and use the result as the attribute value.
2125 Other attribute values use the letter 'A' as the marker, and
2126 the value consists of the form code (encoded as an unsigned
2127 LEB128 value) followed by the encoding of the value according
2128 to the form code. To ensure reproducibility of the signature,
2129 the set of forms used in the signature computation is limited
2130 to the following: \livelink{chap:DWFORMsdata}{DW\-\_FORM\-\_sdata},
2131 \livelink{chap:DWFORMflag}{DW\-\_FORM\-\_flag},
2132 \livelink{chap:DWFORMstring}{DW\-\_FORM\-\_string},
2133 and \livelink{chap:DWFORMblock}{DW\-\_FORM\-\_block}.
2135 \item If the tag in Step 3 is one of \livelink{chap:DWTAGpointertype}{DW\-\_TAG\-\_pointer\-\_type},
2136 \livelink{chap:DWTAGreferencetype}{DW\-\_TAG\-\_reference\-\_type},
2137 \livelink{chap:DWTAGrvaluereferencetype}{DW\-\_TAG\-\_rvalue\-\_reference\-\_type},
2138 \livelink{chap:DWTAGptrtomembertype}{DW\-\_TAG\-\_ptr\-\_to\-\_member\-\_type},
2139 or \livelink{chap:DWTAGfriend}{DW\-\_TAG\-\_friend}, and the referenced
2140 type (via the \livelink{chap:DWATtype}{DW\-\_AT\-\_type} or
2141 \livelink{chap:DWATfriend}{DW\-\_AT\-\_friend} attribute) has a
2142 \livelink{chap:DWATname}{DW\-\_AT\-\_name} attribute, append to S the letter 'N', the DWARF
2143 attribute code (\livelink{chap:DWATtype}{DW\-\_AT\-\_type} or
2144 \livelink{chap:DWATfriend}{DW\-\_AT\-\_friend}), the context of
2145 the type (according to the method in Step 2), the letter 'E',
2146 and the name of the type. For \livelink{chap:DWTAGfriend}{DW\-\_TAG\-\_friend}, if the referenced
2147 entry is a \livelink{chap:DWTAGsubprogram}{DW\-\_TAG\-\_subprogram}, the context is omitted and the
2148 name to be used is the ABI-specific name of the subprogram
2149 (e.g., the mangled linker name).
2152 \item 6.If the tag in Step 3 is not one of \livelink{chap:DWTAGpointertype}{DW\-\_TAG\-\_pointer\-\_type},
2153 \livelink{chap:DWTAGreferencetype}{DW\-\_TAG\-\_reference\-\_type},
2154 \livelink{chap:DWTAGrvaluereferencetype}{DW\-\_TAG\-\_rvalue\-\_reference\-\_type},
2155 \livelink{chap:DWTAGptrtomembertype}{DW\-\_TAG\-\_ptr\-\_to\-\_member\-\_type}, or
2156 \livelink{chap:DWTAGfriend}{DW\-\_TAG\-\_friend}, but has
2157 a \livelink{chap:DWATtype}{DW\-\_AT\-\_type} attribute, or if the referenced type (via
2158 the \livelink{chap:DWATtype}{DW\-\_AT\-\_type} or
2159 \livelink{chap:DWATfriend}{DW\-\_AT\-\_friend} attribute) does not have a
2160 \livelink{chap:DWATname}{DW\-\_AT\-\_name} attribute, the attribute is processed according to
2161 the method in Step 4 for an attribute that refers to another
2165 \item Visit each child C of the debugging information
2166 entry as follows: If C is a nested type entry or a member
2167 function entry, and has a \livelink{chap:DWATname}{DW\-\_AT\-\_name} attribute, append to
2168 S the letter 'S', the tag of C, and its name; otherwise,
2169 process C recursively by performing Steps 3 through 7,
2170 appending the result to S. Following the last child (or if
2171 there are no children), append a zero byte.
2176 For the purposes of this algorithm, if a debugging information
2178 \livelink{chap:DWATspecification}{DW\-\_AT\-\_specification}
2179 attribute that refers to
2180 another entry D (which has a
2181 \livelink{chap:DWATdeclaration}{DW\-\_AT\-\_declaration}
2183 then S inherits the attributes and children of D, and S is
2184 processed as if those attributes and children were present in
2185 the entry S. Exception: if a particular attribute is found in
2186 both S and D, the attribute in S is used and the corresponding
2187 one in D is ignored.
2189 DWARF tag and attribute codes are appended to the sequence
2190 as unsigned LEB128 values, using the values defined earlier
2193 \textit{A grammar describing this computation may be found in
2194 Appendix \refersec{app:typesignaturecomputationgrammar}.
2197 \textit{An attribute that refers to another type entry should
2198 be recursively processed or replaced with the name of the
2199 referent (in Step 4, 5 or 6). If neither treatment applies to
2200 an attribute that references another type entry, the entry
2201 that contains that attribute should not be considered for a
2202 separate type unit.}
2204 \textit{If a debugging information entry contains an attribute from
2205 the list above that would require an unsupported form, that
2206 entry should not be considered for a separate type unit.}
2208 \textit{A type should be considered for a separate type unit only
2209 if all of the type entries that it contains or refers to in
2210 Steps 6 and 7 can themselves each be considered for a separate
2213 Where the DWARF producer may reasonably choose two or more
2214 different forms for a given attribute, it should choose
2215 the simplest possible form in computing the signature. (For
2216 example, a constant value should be preferred to a location
2217 expression when possible.)
2219 Once the string S has been formed from the DWARF encoding,
2220 an MD5 hash is computed for the string and the lower 64 bits
2221 are taken as the type signature.
2223 \textit{The string S is intended to be a flattened representation of
2224 the type that uniquely identifies that type (i.e., a different
2225 type is highly unlikely to produce the same string).}
2227 \textit{A debugging information entry should not be placed in a
2228 separate type unit if any of the following apply:}
2232 \item \textit{The entry has an attribute whose value is a location
2233 expression, and the location expression contains a reference to
2234 another debugging information entry (e.g., a \livelink{chap:DWOPcallref}{DW\-\_OP\-\_call\-\_ref}
2235 operator), as it is unlikely that the entry will remain
2236 identical across compilation units.}
2238 \item \textit{The entry has an attribute whose value refers
2239 to a code location or a location list.}
2241 \item \textit{The entry has an attribute whose value refers
2242 to another debugging information entry that does not represent
2247 \textit{Certain attributes are not included in the type signature:}
2250 \item \textit{The \livelink{chap:DWATdeclaration}{DW\-\_AT\-\_declaration} attribute is not included because it
2251 indicates that the debugging information entry represents an
2252 incomplete declaration, and incomplete declarations should
2253 not be placed in separate type units.}
2255 \item \textit{The \livelink{chap:DWATdescription}{DW\-\_AT\-\_description} attribute is not included because
2256 it does not provide any information unique to the defining
2257 declaration of the type.}
2259 \item \textit{The \livelink{chap:DWATdeclfile}{DW\-\_AT\-\_decl\-\_file}, \livelink{chap:DWATdeclline}{DW\-\_AT\-\_decl\-\_line}, and
2260 \livelink{chap:DWATdeclcolumn}{DW\-\_AT\-\_decl\-\_column} attributes are not included because they
2261 may vary from one source file to the next, and would prevent
2262 two otherwise identical type declarations from producing the