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}).
579 first case, if the flag has value zero, it indicates the
580 absence of the attribute; if the flag has a non\dash zero value,
581 it indicates the presence of the attribute. In the second
582 case, the attribute is implicitly indicated as present, and
583 no value is encoded in the debugging information entry itself.
585 \item \livelink{chap:lineptr}{lineptr} \\
586 This is an offset into the .debug\_line section
587 (\livelink{chap:DWFORMsecoffset}{DW\-\_FORM\-\_sec\-\_offset}). It consists of an offset from the
588 beginning of the .debug\_line section to the first byte of
589 the data making up the line number list for the compilation
591 It is relocatable in a relocatable object file, and
592 relocated in an executable or shared object. In the 32\dash bit
593 DWARF format, this offset is a 4\dash byte unsigned value;
594 in the 64\dash bit DWARF format, it is an 8\dash byte unsigned value
595 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
598 \item \livelink{chap:loclistptr}{loclistptr} \\
599 This is an offset into the .debug\_loc section
600 (\livelink{chap:DWFORMsecoffset}{DW\-\_FORM\-\_sec\-\_offset}). It consists of an offset from the
601 beginning of the .debug\_loc section to the first byte of
602 the data making up the location list for the compilation
604 It is relocatable in a relocatable object file, and
605 relocated in an executable or shared object. In the 32\dash bit
606 DWARF format, this offset is a 4\dash byte unsigned value;
607 in the 64\dash bit DWARF format, it is an 8\dash byte unsigned value
608 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
611 \item \livelink{chap:macptr}{macptr} \\
612 This is an offset into the .debug\_macinfo section
613 (\livelink{chap:DWFORMsecoffset}{DW\-\_FORM\-\_sec\-\_offset}). It consists of an offset from the
614 beginning of the .debug\_macinfo section to the first byte of
615 the data making up the macro information list for the compilation
617 It is relocatable in a relocatable object file, and
618 relocated in an executable or shared object. In the 32\dash bit
619 DWARF format, this offset is a 4\dash byte unsigned value;
620 in the 64\dash bit DWARF format, it is an 8\dash byte unsigned value
621 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
623 \item \livelink{chap:rangelistptr}{rangelistptr} \\
624 This is an offset into the .debug\_ranges section
625 (\livelink{chap:DWFORMsecoffset}{DW\-\_FORM\-\_sec\-\_offset}).
627 offset from the beginning of the .debug\_ranges section
628 to the beginning of the non\dash contiguous address ranges
629 information for the referencing entity.
631 a relocatable object file, and relocated in an executable or
632 shared object. In the 32\dash bit DWARF format, this offset
633 is a 4\dash byte unsigned value; in the 64\dash bit DWARF
634 format, it is an 8\dash byte unsigned value (see Section
635 \refersec{datarep:32bitand64bitdwarfformats}).
638 \textit{Because classes \livelink{chap:lineptr}{lineptr}, \livelink{chap:loclistptr}{loclistptr}, \livelink{chap:macptr}{macptr} and \livelink{chap:rangelistptr}{rangelistptr}
639 share a common representation, it is not possible for an
640 attribute to allow more than one of these classes}
645 There are three types of reference.
647 The first type of reference can identify any debugging
648 information entry within the containing unit. This type of
649 reference is an offset from the first byte of the compilation
650 header for the compilation unit containing the reference. There
651 are five forms for this type of reference. There are fixed
652 length forms for one, two, four and eight byte offsets
653 (respectively, \livetarg{chap:DWFORMref1}{DW\-\_FORM\-\_ref1},
654 \livetarg{chap:DWFORMref2}{DW\-\_FORM\-\_ref2},
655 \livetarg{chap:DWFORMref4}{DW\-\_FORM\-\_ref4},
656 and \livetarg{chap:DWFORMref8}{DW\-\_FORM\-\_ref8}).
657 There is also an unsigned variable
658 length offset encoded form that uses unsigned LEB128 numbers
659 (\livetarg{chap:DWFORMrefudata}{DW\-\_FORM\-\_ref\-\_udata}).
660 Because this type of reference is within
661 the containing compilation unit no relocation of the value
664 The second type of reference can identify any debugging
665 information entry within a .debug\_info section; in particular,
666 it may refer to an entry in a different compilation unit
667 from the unit containing the reference, and may refer to an
668 entry in a different shared object. This type of reference
669 (\livetarg{chap:DWFORMrefaddr}{DW\-\_FORM\-\_ref\-\_addr}) is an offset from the beginning of the
670 .debug\_info section of the target executable or shared object;
671 it is relocatable in a relocatable object file and frequently
672 relocated in an executable file or shared object. For
673 references from one shared object or static executable file
674 to another, the relocation and identification of the target
675 object must be performed by the consumer. In the 32\dash bit DWARF
676 format, this offset is a 4\dash byte unsigned value;
677 in the 64\dash bit DWARF format, it is an 8\dash byte
679 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
681 A debugging information entry that may be referenced by
682 another compilation unit using \livelink{chap:DWFORMrefaddr}{DW\-\_FORM\-\_ref\-\_addr} must have a
683 global symbolic name.
685 For a reference from one executable or shared object to
686 another, the reference is resolved by the debugger to identify
687 the shared object or executable and the offset into that
688 object’s .debug\_info section in the same fashion as the run
689 time loader, either when the debug information is first read,
690 or when the reference is used.
692 The third type of reference can identify any debugging
693 information type entry that has been placed in its own
694 type unit. This type of
695 reference (\livetarg{chap:DWFORMrefsig8}{DW\-\_FORM\-\_ref\-\_sig8}) is the
696 64\dash bit type signature
697 (see Section \refersec{datarep:typesignaturecomputation})
701 The use of compilation unit relative references will reduce the
702 number of link\dash time relocations and so speed up linking. The
703 use of the second and third type of reference allows for the
704 sharing of information, such as types, across compilation
707 A reference to any kind of compilation unit identifies the
708 debugging information entry for that unit, not the preceding
712 A string is a sequence of contiguous non\dash null bytes followed by
713 one null byte. A string may be represented immediately in the
714 debugging information entry itself
715 (\livetarg{chap:DWFORMstring}{DW\-\_FORM\-\_string}), or may
716 be represented as an offset into a string table contained in
717 the .debug\_str section of the object file
718 (\livetarg{chap:DWFORMstrp}{DW\-\_FORM\-\_strp}). In
719 the 32\dash bit DWARF format, the representation of a
720 \livelink{chap:DWFORMstrp}{DW\-\_FORM\-\_strp}
721 value is a 4\dash byte unsigned offset; in the 64\dash bit DWARF format,
722 it is an 8\dash byte unsigned offset
723 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
725 If the \livelink{chap:DWATuseUTF8}{DW\-\_AT\-\_use\-\_UTF8} attribute is specified for the
726 compilation unit entry, string values are encoded using the
727 UTF\dash 8 (Unicode Transformation Format\dash 8) from the Universal
728 Character Set standard (ISO/IEC 10646\dash 1:1993). Otherwise,
729 the string representation is unspecified.
731 The Unicode Standard Version 3 is fully compatible with
732 ISO/IEC 10646\dash 1:1993. It contains all the same characters
733 and encoding points as ISO/IEC 10646, as well as additional
734 information about the characters and their use.
736 Earlier versions of DWARF did not specify the representation
737 of strings; for compatibility, this version also does
738 not. However, the UTF\dash 8 representation is strongly recommended.
742 In no case does an attribute use one of the classes \livelink{chap:lineptr}{lineptr},
743 \livelink{chap:loclistptr}{loclistptr}, \livelink{chap:macptr}{macptr} or \livelink{chap:rangelistptr}{rangelistptr} to point into either the
744 .debug\_info or .debug\_str section.
746 The form encodings are listed in
747 Table \refersec{tab:attributeformencodings}.
750 \setlength{\extrarowheight}{0.1cm}
751 \begin{longtable}{l|l}
752 \caption{Tag encodings} \label{tab:tagencodings} \\
753 \hline \\ \bfseries Tag name&\bfseries Value\\ \hline
755 \bfseries Tag name&\bfseries Value \\ \hline
757 \hline \emph{Continued on next page}
761 \livelink{chap:DWTAGarraytype}{DW\-\_TAG\-\_array\-\_type} &0x01 \\
762 \livelink{chap:DWTAGclasstype}{DW\-\_TAG\-\_class\-\_type}&0x02 \\
763 \livelink{chap:DWTAGentrypoint}{DW\-\_TAG\-\_entry\-\_point}&0x03 \\
764 \livelink{chap:DWTAGenumerationtype}{DW\-\_TAG\-\_enumeration\-\_type}&0x04 \\
765 \livelink{chap:DWTAGformalparameter}{DW\-\_TAG\-\_formal\-\_parameter}&0x05 \\
766 \livelink{chap:DWTAGimporteddeclaration}{DW\-\_TAG\-\_imported\-\_declaration}&0x08 \\
767 \livelink{chap:DWTAGlabel}{DW\-\_TAG\-\_label}&0x0a \\
768 \livelink{chap:DWTAGlexicalblock}{DW\-\_TAG\-\_lexical\-\_block}&0x0b \\
769 \livelink{chap:DWTAGmember}{DW\-\_TAG\-\_member}&0x0d \\
770 \livelink{chap:DWTAGpointertype}{DW\-\_TAG\-\_pointer\-\_type}&0x0f \\
771 \livelink{chap:DWTAGreferencetype}{DW\-\_TAG\-\_reference\-\_type}&0x10 \\
772 \livelink{chap:DWTAGcompileunit}{DW\-\_TAG\-\_compile\-\_unit}&0x11 \\
773 \livelink{chap:DWTAGstringtype}{DW\-\_TAG\-\_string\-\_type}&0x12 \\
774 \livelink{chap:DWTAGstructuretype}{DW\-\_TAG\-\_structure\-\_type}&0x13 \\
775 \livelink{chap:DWTAGsubroutinetype}{DW\-\_TAG\-\_subroutine\-\_type}&0x15 \\
776 \livelink{chap:DWTAGtypedef}{DW\-\_TAG\-\_typedef}&0x16 \\
777 \livelink{chap:DWTAGuniontype}{DW\-\_TAG\-\_union\-\_type}&0x17 \\
778 \livelink{chap:DWTAGunspecifiedparameters}{DW\-\_TAG\-\_unspecified\-\_parameters}&0x18 \\
779 \livelink{chap:DWTAGvariant}{DW\-\_TAG\-\_variant}&0x19 \\
780 \livelink{chap:DWTAGcommonblock}{DW\-\_TAG\-\_common\-\_block}&0x1a \\
781 \livelink{chap:DWTAGcommoninclusion}{DW\-\_TAG\-\_common\-\_inclusion}&0x1b \\
782 \livelink{chap:DWTAGinheritance}{DW\-\_TAG\-\_inheritance}&0x1c \\
783 \livelink{chap:DWTAGinlinedsubroutine}{DW\-\_TAG\-\_inlined\-\_subroutine}&0x1d \\
784 \livelink{chap:DWTAGmodule}{DW\-\_TAG\-\_module}&0x1e \\
785 \livelink{chap:DWTAGptrtomembertype}{DW\-\_TAG\-\_ptr\-\_to\-\_member\-\_type}&0x1f \\
786 \livelink{chap:DWTAGsettype}{DW\-\_TAG\-\_set\-\_type}&0x20 \\
787 \livelink{chap:DWTAGsubrangetype}{DW\-\_TAG\-\_subrange\-\_type}&0x21 \\
788 \livelink{chap:DWTAGwithstmt}{DW\-\_TAG\-\_with\-\_stmt}&0x22 \\
789 \livelink{chap:DWTAGaccessdeclaration}{DW\-\_TAG\-\_access\-\_declaration}&0x23 \\
790 \livelink{chap:DWTAGbasetype}{DW\-\_TAG\-\_base\-\_type}&0x24 \\
791 \livelink{chap:DWTAGcatchblock}{DW\-\_TAG\-\_catch\-\_block}&0x25 \\
792 \livelink{chap:DWTAGconsttype}{DW\-\_TAG\-\_const\-\_type}&0x26 \\
793 \livelink{chap:DWTAGconstant}{DW\-\_TAG\-\_constant}&0x27 \\
794 \livelink{chap:DWTAGenumerator}{DW\-\_TAG\-\_enumerator}&0x28 \\
795 \livelink{chap:DWTAGfiletype}{DW\-\_TAG\-\_file\-\_type}&0x29 \\
796 \livelink{chap:DWTAGfriend}{DW\-\_TAG\-\_friend}&0x2a \\
797 \livelink{chap:DWTAGnamelist}{DW\-\_TAG\-\_namelist}&0x2b \\
798 \livelink{chap:DWTAGnamelistitem}{DW\-\_TAG\-\_namelist\-\_item}&0x2c \\
799 \livelink{chap:DWTAGpackedtype}{DW\-\_TAG\-\_packed\-\_type}&0x2d \\
800 \livelink{chap:DWTAGsubprogram}{DW\-\_TAG\-\_subprogram}&0x2e \\
801 \livelink{chap:DWTAGtemplatetypeparameter}{DW\-\_TAG\-\_template\-\_type\-\_parameter}&0x2f \\
802 \livelink{chap:DWTAGtemplatevalueparameter}{DW\-\_TAG\-\_template\-\_value\-\_parameter}&0x30 \\
803 \livelink{chap:DWTAGthrowntype}{DW\-\_TAG\-\_thrown\-\_type}&0x31 \\
804 \livelink{chap:DWTAGtryblock}{DW\-\_TAG\-\_try\-\_block}&0x32 \\
805 \livelink{chap:DWTAGvariantpart}{DW\-\_TAG\-\_variant\-\_part}&0x33 \\
806 \livelink{chap:DWTAGvariable}{DW\-\_TAG\-\_variable}&0x34 \\
807 \livelink{chap:DWTAGvolatiletype}{DW\-\_TAG\-\_volatile\-\_type}&0x35 \\
808 \livelink{chap:DWTAGdwarfprocedure}{DW\-\_TAG\-\_dwarf\-\_procedure}&0x36 \\
809 \livelink{chap:DWTAGrestricttype}{DW\-\_TAG\-\_restrict\-\_type}&0x37 \\
810 \livelink{chap:DWTAGinterfacetype}{DW\-\_TAG\-\_interface\-\_type}&0x38 \\
811 \livelink{chap:DWTAGnamespace}{DW\-\_TAG\-\_namespace}&0x39 \\
812 \livelink{chap:DWTAGimportedmodule}{DW\-\_TAG\-\_imported\-\_module}&0x3a \\
813 \livelink{chap:DWTAGunspecifiedtype}{DW\-\_TAG\-\_unspecified\-\_type}&0x3b \\
814 \livelink{chap:DWTAGpartialunit}{DW\-\_TAG\-\_partial\-\_unit}&0x3c \\
815 \livelink{chap:DWTAGimportedunit}{DW\-\_TAG\-\_imported\-\_unit}&0x3d \\
816 \livelink{chap:DWTAGcondition}{DW\-\_TAG\-\_condition}&0x3f \\
817 \livelink{chap:DWTAGsharedtype}{DW\-\_TAG\-\_shared\-\_type}&0x40 \\
818 \livelink{chap:DWTAGtypeunit}{DW\-\_TAG\-\_type\-\_unit} \ddag &0x41 \\
819 \livelink{chap:DWTAGrvaluereferencetype}{DW\-\_TAG\-\_rvalue\-\_reference\-\_type} \ddag &0x42 \\
820 \livelink{chap:DWTAGtemplatealias}{DW\-\_TAG\-\_template\-\_alias} \ddag &0x43 \\
821 \livelink{chap:DWTAGlouser}{DW\-\_TAG\-\_lo\-\_user}&0x4080 \\
822 \livelink{chap:DWTAGhiuser}{DW\-\_TAG\-\_hi\-\_user}&0xffff \\
824 \ddag TAG new in DWARF Version 4
830 \setlength{\extrarowheight}{0.1cm}
831 \caption{Child determination encodings}
832 \label{tab:childdeterminationencodings}
833 \begin{tabular}{l|l} \hline
834 Child determination name& Value\\ \hline
835 \livelink{chap:DWCHILDRENno}{DW\-\_CHILDREN\-\_no}&0x00 \\
836 \livelink{chap:DWCHILDRENyes}{DW\-\_CHILDREN\-\_yes}&0x01 \\ \hline
842 \setlength{\extrarowheight}{0.1cm}
843 \begin{longtable}{l|l|l}
844 \caption{Attribute encodings} \label{tab:attributeencodings} \\
845 \hline \\ \bfseries Attribute name&\bfseries Value &\bfseries Classes \\ \hline
847 \bfseries Attribute name&\bfseries Value &\bfseries Classes\\ \hline
849 \hline \emph{Continued on next page}
853 \livelink{chap:DWATsibling}{DW\-\_AT\-\_sibling}&0x01&reference \\
854 \livelink{chap:DWATlocation}{DW\-\_AT\-\_location}&0x02&\livelink{chap:exprloc}{exprloc}, \livelink{chap:loclistptr}{loclistptr} \\
855 \livelink{chap:DWATname}{DW\-\_AT\-\_name}&0x03&string \\
856 \livelink{chap:DWATordering}{DW\-\_AT\-\_ordering}&0x09&constant \\
857 \livelink{chap:DWATbytesize}{DW\-\_AT\-\_byte\-\_size}&0x0b&constant, \livelink{chap:exprloc}{exprloc}, reference \\
858 \livelink{chap:DWATbitoffset}{DW\-\_AT\-\_bit\-\_offset}&0x0c&constant, \livelink{chap:exprloc}{exprloc}, reference \\
859 \livelink{chap:DWATbitsize}{DW\-\_AT\-\_bit\-\_size}&0x0d&constant, \livelink{chap:exprloc}{exprloc}, reference \\
860 \livelink{chap:DWATstmtlist}{DW\-\_AT\-\_stmt\-\_list}&0x10&\livelink{chap:lineptr}{lineptr} \\
861 \livelink{chap:DWATlowpc}{DW\-\_AT\-\_low\-\_pc}&0x11&address \\
862 \livelink{chap:DWAThighpc}{DW\-\_AT\-\_high\-\_pc}&0x12&address, constant \\
863 \livelink{chap:DWATlanguage}{DW\-\_AT\-\_language}&0x13&constant \\
864 \livelink{chap:DWATdiscr}{DW\-\_AT\-\_discr}&0x15&reference \\
865 \livelink{chap:DWATdiscrvalue}{DW\-\_AT\-\_discr\-\_value}&0x16&constant \\
866 \livelink{chap:DWATvisibility}{DW\-\_AT\-\_visibility}&0x17&constant \\
867 \livelink{chap:DWATimport}{DW\-\_AT\-\_import}&0x18&reference \\
868 \livelink{chap:DWATstringlength}{DW\-\_AT\-\_string\-\_length}&0x19&\livelink{chap:exprloc}{exprloc}, \livelink{chap:loclistptr}{loclistptr} \\
869 \livelink{chap:DWATcommonreference}{DW\-\_AT\-\_common\-\_reference}&0x1a&reference \\
870 \livelink{chap:DWATcompdir}{DW\-\_AT\-\_comp\-\_dir}&0x1b&string \\
871 \livelink{chap:DWATconstvalue}{DW\-\_AT\-\_const\-\_value}&0x1c&block, constant, string \\
872 \livelink{chap:DWATcontainingtype}{DW\-\_AT\-\_containing\-\_type}&0x1d&reference \\
873 \livelink{chap:DWATdefaultvalue}{DW\-\_AT\-\_default\-\_value}&0x1e&reference \\
874 \livelink{chap:DWATinline}{DW\-\_AT\-\_inline}&0x20&constant \\
875 \livelink{chap:DWATisoptional}{DW\-\_AT\-\_is\-\_optional}&0x21&\livelink{chap:flag}{flag} \\
876 \livelink{chap:DWATlowerbound}{DW\-\_AT\-\_lower\-\_bound}&0x22&constant, \livelink{chap:exprloc}{exprloc}, reference \\
877 \livelink{chap:DWATproducer}{DW\-\_AT\-\_producer}&0x25&string \\
878 \livelink{chap:DWATprototyped}{DW\-\_AT\-\_prototyped}&0x27&\livelink{chap:flag}{flag} \\
879 \livelink{chap:DWATreturnaddr}{DW\-\_AT\-\_return\-\_addr}&0x2a&\livelink{chap:exprloc}{exprloc}, \livelink{chap:loclistptr}{loclistptr} \\
880 % FIXME: lower case , not Constant
881 \livelink{chap:DWATstartscope}{DW\-\_AT\-\_start\-\_scope}&0x2c&Constant, \livelink{chap:rangelistptr}{rangelistptr} \\
882 \livelink{chap:DWATbitstride}{DW\-\_AT\-\_bit\-\_stride}&0x2e&constant, \livelink{chap:exprloc}{exprloc}, reference \\
883 \livelink{chap:DWATupperbound}{DW\-\_AT\-\_upper\-\_bound}&0x2f&constant, \livelink{chap:exprloc}{exprloc}, reference \\
884 \livelink{chap:DWATabstractorigin}{DW\-\_AT\-\_abstract\-\_origin}&0x31&reference \\
885 \livelink{chap:DWATaccessibility}{DW\-\_AT\-\_accessibility}&0x32&constant \\
886 \livelink{chap:DWATaddressclass}{DW\-\_AT\-\_address\-\_class}&0x33&constant \\
887 \livelink{chap:DWATartificial}{DW\-\_AT\-\_artificial}&0x34&\livelink{chap:flag}{flag} \\
888 \livelink{chap:DWATbasetypes}{DW\-\_AT\-\_base\-\_types}&0x35&reference \\
889 \livelink{chap:DWATcallingconvention}{DW\-\_AT\-\_calling\-\_convention}&0x36&constant \\
890 \livelink{chap:DWATcount}{DW\-\_AT\-\_count}&0x37&constant, \livelink{chap:exprloc}{exprloc}, reference \\
891 \livelink{chap:DWATdatamemberlocation}{DW\-\_AT\-\_data\-\_member\-\_location}&0x38&constant, \livelink{chap:exprloc}{exprloc}, \livelink{chap:loclistptr}{loclistptr} \\
892 \livelink{chap:DWATdeclcolumn}{DW\-\_AT\-\_decl\-\_column}&0x39&constant \\
893 \livelink{chap:DWATdeclfile}{DW\-\_AT\-\_decl\-\_file}&0x3a&constant \\
894 \livelink{chap:DWATdeclline}{DW\-\_AT\-\_decl\-\_line}&0x3b&constant \\
895 \livelink{chap:DWATdeclaration}{DW\-\_AT\-\_declaration}&0x3c&\livelink{chap:flag}{flag} \\
896 \livelink{chap:DWATdiscrlist}{DW\-\_AT\-\_discr\-\_list}&0x3d&block \\
897 \livelink{chap:DWATencoding}{DW\-\_AT\-\_encoding}&0x3e&constant \\
898 \livelink{chap:DWATexternal}{DW\-\_AT\-\_external}&0x3f&\livelink{chap:flag}{flag} \\
899 \livelink{chap:DWATframebase}{DW\-\_AT\-\_frame\-\_base}&0x40&\livelink{chap:exprloc}{exprloc}, \livelink{chap:loclistptr}{loclistptr} \\
900 \livelink{chap:DWATfriend}{DW\-\_AT\-\_friend}&0x41&reference \\
901 \livelink{chap:DWATidentifiercase}{DW\-\_AT\-\_identifier\-\_case}&0x42&constant \\
902 \livelink{chap:DWATmacroinfo}{DW\-\_AT\-\_macro\-\_info}&0x43&\livelink{chap:macptr}{macptr} \\
903 \livelink{chap:DWATnamelistitem}{DW\-\_AT\-\_namelist\-\_item}&0x44&reference \\
904 \livelink{chap:DWATpriority}{DW\-\_AT\-\_priority}&0x45&reference \\
905 \livelink{chap:DWATsegment}{DW\-\_AT\-\_segment}&0x46&\livelink{chap:exprloc}{exprloc}, \livelink{chap:loclistptr}{loclistptr} \\
906 \livelink{chap:DWATspecification}{DW\-\_AT\-\_specification}&0x47&reference \\
907 \livelink{chap:DWATstaticlink}{DW\-\_AT\-\_static\-\_link}&0x48&\livelink{chap:exprloc}{exprloc}, \livelink{chap:loclistptr}{loclistptr} \\
908 \livelink{chap:DWATtype}{DW\-\_AT\-\_type}&0x49&reference \\
909 \livelink{chap:DWATuselocation}{DW\-\_AT\-\_use\-\_location}&0x4a&\livelink{chap:exprloc}{exprloc}, \livelink{chap:loclistptr}{loclistptr} \\
910 \livelink{chap:DWATvariableparameter}{DW\-\_AT\-\_variable\-\_parameter}&0x4b&\livelink{chap:flag}{flag} \\
911 \livelink{chap:DWATvirtuality}{DW\-\_AT\-\_virtuality}&0x4c&constant \\
912 \livelink{chap:DWATvtableelemlocation}{DW\-\_AT\-\_vtable\-\_elem\-\_location}&0x4d&\livelink{chap:exprloc}{exprloc}, \livelink{chap:loclistptr}{loclistptr} \\
915 \livelink{chap:DWATallocated}{DW\-\_AT\-\_allocated}&0x4e&constant, \livelink{chap:exprloc}{exprloc}, reference \\
916 \livelink{chap:DWATassociated}{DW\-\_AT\-\_associated}&0x4f&constant, \livelink{chap:exprloc}{exprloc}, reference \\
917 \livelink{chap:DWATdatalocation}{DW\-\_AT\-\_data\-\_location}&0x50&\livelink{chap:exprloc}{exprloc} \\
918 \livelink{chap:DWATbytestride}{DW\-\_AT\-\_byte\-\_stride}&0x51&constant, \livelink{chap:exprloc}{exprloc}, reference \\
919 \livelink{chap:DWATentrypc}{DW\-\_AT\-\_entry\-\_pc}&0x52&address \\
920 \livelink{chap:DWATuseUTF8}{DW\-\_AT\-\_use\-\_UTF8}&0x53&\livelink{chap:flag}{flag} \\
921 \livelink{chap:DWATextension}{DW\-\_AT\-\_extension}&0x54&reference \\
922 \livelink{chap:DWATranges}{DW\-\_AT\-\_ranges}&0x55&\livelink{chap:rangelistptr}{rangelistptr} \\
923 \livelink{chap:DWATtrampoline}{DW\-\_AT\-\_trampoline}&0x56&address, \livelink{chap:flag}{flag}, reference, string \\
924 \livelink{chap:DWATcallcolumn}{DW\-\_AT\-\_call\-\_column}&0x57&constant \\
925 \livelink{chap:DWATcallfile}{DW\-\_AT\-\_call\-\_file}&0x58&constant \\
926 \livelink{chap:DWATcallline}{DW\-\_AT\-\_call\-\_line}&0x59&constant \\
927 \livelink{chap:DWATdescription}{DW\-\_AT\-\_description}&0x5a&string \\
928 \livelink{chap:DWATbinaryscale}{DW\-\_AT\-\_binary\-\_scale}&0x5b&constant \\
929 \livelink{chap:DWATdecimalscale}{DW\-\_AT\-\_decimal\-\_scale}&0x5c&constant \\
930 \livelink{chap:DWATsmall}{DW\-\_AT\-\_small} &0x5d&reference \\
931 \livelink{chap:DWATdecimalsign}{DW\-\_AT\-\_decimal\-\_sign}&0x5e&constant \\
932 \livelink{chap:DWATdigitcount}{DW\-\_AT\-\_digit\-\_count}&0x5f&constant \\
933 \livelink{chap:DWATpicturestring}{DW\-\_AT\-\_picture\-\_string}&0x60&string \\
934 \livelink{chap:DWATmutable}{DW\-\_AT\-\_mutable}&0x61&\livelink{chap:flag}{flag} \\
937 \livelink{chap:DWATthreadsscaled}{DW\-\_AT\-\_threads\-\_scaled}&0x62&\livelink{chap:flag}{flag} \\
938 \livelink{chap:DWATexplicit}{DW\-\_AT\-\_explicit}&0x63&\livelink{chap:flag}{flag} \\
939 \livelink{chap:DWATobjectpointer}{DW\-\_AT\-\_object\-\_pointer}&0x64&reference \\
940 \livelink{chap:DWATendianity}{DW\-\_AT\-\_endianity}&0x65&constant \\
941 \livelink{chap:DWATelemental}{DW\-\_AT\-\_elemental}&0x66&\livelink{chap:flag}{flag} \\
942 \livelink{chap:DWATpure}{DW\-\_AT\-\_pure}&0x67&\livelink{chap:flag}{flag} \\
943 \livelink{chap:DWATrecursive}{DW\-\_AT\-\_recursive}&0x68&\livelink{chap:flag}{flag} \\
944 \livelink{chap:DWATsignature}{DW\-\_AT\-\_signature} \ddag &0x69&reference \\
945 \livelink{chap:DWATmainsubprogram}{DW\-\_AT\-\_main\-\_subprogram} \ddag &0x6a&\livelink{chap:flag}{flag} \\
946 \livelink{chap:DWATdatabitoffset}{DW\-\_AT\-\_data\-\_bit\-\_offset} \ddag &0x6b&constant \\
947 \livelink{chap:DWATconstexpr}{DW\-\_AT\-\_const\-\_expr} \ddag &0x6c&\livelink{chap:flag}{flag} \\
948 \livelink{chap:DWATenumclass}{DW\-\_AT\-\_enum\-\_class} \ddag &0x6d&\livelink{chap:flag}{flag} \\
949 \livelink{chap:DWATlinkagename}{DW\-\_AT\-\_linkage\-\_name} \ddag &0x6e&string \\
950 \livetarg{chap:DWATlouser}{DW\-\_AT\-\_lo\-\_user}&0x2000 & --- \\
951 \livetarg{chap:DWAThiuser}{DW\-\_AT\-\_hi\-\_user}&0x3fff& --- \\
954 \ddag Attribute new in DWARF Version 4
958 \setlength{\extrarowheight}{0.1cm}
959 \begin{longtable}{l|l|l}
960 \caption{Attribute form encodings} \label{tab:attributeformencodings} \\
961 \hline \\ \bfseries Form name&\bfseries Value &\bfseries Classes \\ \hline
963 \bfseries Form name&\bfseries Value &\bfseries Classes\\ \hline
965 \hline \emph{Continued on next page}
969 \livelink{chap:DWFORMaddr}{DW\-\_FORM\-\_addr}&0x01&address \\
970 \livelink{chap:DWFORMblock2}{DW\-\_FORM\-\_block2}&0x03&block \\
971 \livelink{chap:DWFORMblock4}{DW\-\_FORM\-\_block4}&0x04&block \\
972 \livelink{chap:DWFORMdata2}{DW\-\_FORM\-\_data2}&0x05&constant \\
973 \livelink{chap:DWFORMdata4}{DW\-\_FORM\-\_data4}&0x06&constant \\
974 \livelink{chap:DWFORMdata8}{DW\-\_FORM\-\_data8}&0x07&constant \\
975 \livelink{chap:DWFORMstring}{DW\-\_FORM\-\_string}&0x08&string \\
976 \livelink{chap:DWFORMblock}{DW\-\_FORM\-\_block}&0x09&block \\
977 \livelink{chap:DWFORMblock1}{DW\-\_FORM\-\_block1}&0x0a&block \\
978 \livelink{chap:DWFORMdata1}{DW\-\_FORM\-\_data1}&0x0b&constant \\
979 \livelink{chap:DWFORMflag}{DW\-\_FORM\-\_flag}&0x0c&\livelink{chap:flag}{flag} \\
980 \livelink{chap:DWFORMsdata}{DW\-\_FORM\-\_sdata}&0x0d&constant \\
981 \livelink{chap:DWFORMstrp}{DW\-\_FORM\-\_strp}&0x0e&string \\
982 \livelink{chap:DWFORMudata}{DW\-\_FORM\-\_udata}&0x0f&constant \\
983 \livelink{chap:DWFORMrefaddr}{DW\-\_FORM\-\_ref\-\_addr}&0x10&reference \\
984 \livelink{chap:DWFORMref1}{DW\-\_FORM\-\_ref1}&0x11&reference \\
985 \livelink{chap:DWFORMref2}{DW\-\_FORM\-\_ref2}&0x12&reference \\
986 \livelink{chap:DWFORMref4}{DW\-\_FORM\-\_ref4}&0x13&reference \\
987 \livelink{chap:DWFORMref8}{DW\-\_FORM\-\_ref8}&0x14&reference \\
988 \livelink{chap:DWFORMrefudata}{DW\-\_FORM\-\_ref\-\_udata}&0x15&reference \\
989 \livelink{chap:DWFORMindirect}{DW\-\_FORM\-\_indirect}&0x16&(see Section \refersec{datarep:abbreviationstables}) \\
990 \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} \\
991 \livelink{chap:DWFORMexprloc}{DW\-\_FORM\-\_exprloc} \ddag &0x18&\livelink{chap:exprloc}{exprloc} \\
992 \livelink{chap:DWFORMflagpresent}{DW\-\_FORM\-\_flag\-\_present} \ddag &0x19&\livelink{chap:flag}{flag} \\
993 \livelink{chap:DWFORMrefsig8}{DW\-\_FORM\-\_ref\-\_sig8} \ddag &0x20&reference \\
996 \ddag FORM new in DWARF Version 4
999 \section{Variable Length Data}
1000 \label{datarep:variablelengthdata}
1001 Integers may be encoded using ``Little Endian Base 128''
1002 (LEB128) numbers. LEB128 is a scheme for encoding integers
1003 densely that exploits the assumption that most integers are
1006 This encoding is equally suitable whether the target machine
1007 architecture represents data in big\dash\ endian or little\dash endian
1008 order. It is ``little\dash endian'' only in the sense that it
1009 avoids using space to represent the ``big'' end of an
1010 unsigned integer, when the big end is all zeroes or sign
1013 Unsigned LEB128 (ULEB128) numbers are encoded as follows:
1014 start at the low order end of an unsigned integer and chop
1015 it into 7\dash bit chunks. Place each chunk into the low order 7
1016 bits of a byte. Typically, several of the high order bytes
1017 will be zero; discard them. Emit the remaining bytes in a
1018 stream, starting with the low order byte; set the high order
1019 bit on each byte except the last emitted byte. The high bit
1020 of zero on the last byte indicates to the decoder that it
1021 has encountered the last byte.
1023 The integer zero is a special case, consisting of a single
1026 Table \refersec{tab:examplesofunsignedleb128encodings}
1027 gives some examples of unsigned LEB128 numbers. The
1028 0x80 in each case is the high order bit of the byte, indicating
1029 that an additional byte follows.
1032 The encoding for signed, two’s complement LEB128 (SLEB128)
1033 numbers is similar, except that the criterion for discarding
1034 high order bytes is not whether they are zero, but whether
1035 they consist entirely of sign extension bits. Consider the
1036 32\dash bit integer -2. The three high level bytes of the number
1037 are sign extension, thus LEB128 would represent it as a single
1038 byte containing the low order 7 bits, with the high order
1039 bit cleared to indicate the end of the byte stream. Note
1040 that there is nothing within the LEB128 representation that
1041 indicates whether an encoded number is signed or unsigned. The
1042 decoder must know what type of number to expect.
1043 Table \refersec{tab:examplesofunsignedleb128encodings}
1044 gives some examples of unsigned LEB128 numbers and
1045 Table \refersec{tab:examplesofsignedleb128encodings}
1046 gives some examples of signed LEB128 numbers.
1048 Appendix \refersec{app:variablelengthdataencodingdecodinginformative}
1049 gives algorithms for encoding and decoding these forms.
1053 \setlength{\extrarowheight}{0.1cm}
1054 \begin{longtable}{l|l|l}
1055 \caption{Examples of unsigned LEB32 encodings} \label{tab:examplesofunsignedleb128encodings} \\
1056 \hline \\ \bfseries Number&\bfseries First byte &\bfseries Second byte \\ \hline
1058 \bfseries Number&\bfseries First Byte &\bfseries Second byte\\ \hline
1060 \hline \emph{Continued on next page}
1066 128& 0 + 0x80 & 1 \\
1067 129& 1 + 0x80 & 1 \\
1068 130& 2 + 0x80 & 1 \\
1069 12857& 57 + 0x80 & 100 \\
1077 \setlength{\extrarowheight}{0.1cm}
1078 \begin{longtable}{l|l|l}
1079 \caption{Examples of signed LEB32 encodings} \label{tab:examplesofsignedleb128encodings} \\
1080 \hline \\ \bfseries Number&\bfseries First byte &\bfseries Second byte \\ \hline
1082 \bfseries Number&\bfseries First Byte &\bfseries Second byte\\ \hline
1084 \hline \emph{Continued on next page}
1090 127& 127 + 0x80 & 0 \\
1091 -127& 1 + 0x80 & 0x7f \\
1092 128& 0 + 0x80 & 1 \\
1093 -128& 0 + 0x80 & 0x7f \\
1094 129& 1 + 0x80 & 1 \\
1095 -129& -x7f + 0x80 & 0xtc \\
1102 \section{DWARF Expressions and Location Descriptions}
1103 \label{datarep:dwarfexpressionsandlocationdescriptions}
1104 \subsection{DWARF Expressions}
1105 \label{datarep:dwarfexpressions}
1107 A DWARF expression is stored in a block of contiguous
1108 bytes. The bytes form a sequence of operations. Each operation
1109 is a 1\dash byte code that identifies that operation, followed by
1110 zero or more bytes of additional data. The encodings for the
1111 operations are described in
1112 Table \refersec{tab:dwarfoperationencodings}.
1115 \setlength{\extrarowheight}{0.1cm}
1116 \begin{longtable}{l|l|l|l}
1117 \caption{DWARF operation encodings} \label{tab:dwarfoperationencodings} \\
1118 \hline \\ & &\bfseries No. of &\\
1119 \bfseries Operation&\bfseries Code &\bfseries Operands &\bfseries Notes\\ \hline
1121 & &\bfseries No. of &\\
1122 \bfseries Operation&\bfseries Code &\bfseries Operands &\bfseries Notes\\ \hline
1124 \hline \emph{Continued on next page}
1129 \livelink{chap:DWOPaddr}{DW\-\_OP\-\_addr}&0x03&1 & constant address \\
1130 & & &(size target specific) \\
1132 \livelink{chap:DWOPderef}{DW\-\_OP\-\_deref}&0x06&0 & \\
1135 \livelink{chap:DWOPconst1u}{DW\-\_OP\-\_const1u}&0x08&1&1\dash byte constant \\
1136 \livelink{chap:DWOPconst1s}{DW\-\_OP\-\_const1s}&0x09&1&1\dash byte constant \\
1137 \livelink{chap:DWOPconst2u}{DW\-\_OP\-\_const2u}&0x0a&1&2\dash byte constant \\
1138 \livelink{chap:DWOPconst2s}{DW\-\_OP\-\_const2s}&0x0b&1&2\dash byte constant \\
1139 \livelink{chap:DWOPconst4u}{DW\-\_OP\-\_const4u}&0x0c&1&4\dash byte constant \\
1140 \livelink{chap:DWOPconst4s}{DW\-\_OP\-\_const4s}&0x0d&1&4\dash byte constant \\
1141 \livelink{chap:DWOPconst8u}{DW\-\_OP\-\_const8u}&0x0e&1&8\dash byte constant \\
1142 \livelink{chap:DWOPconst8s}{DW\-\_OP\-\_const8s}&0x0f&1&8\dash byte constant \\
1143 \livelink{chap:DWOPconstu}{DW\-\_OP\-\_constu}&0x10&1&ULEB128 constant \\
1144 \livelink{chap:DWOPconsts}{DW\-\_OP\-\_consts}&0x11&1&SLEB128 constant \\
1145 \livelink{chap:DWOPdup}{DW\-\_OP\-\_dup}&0x12&0 & \\
1146 \livelink{chap:DWOPdrop}{DW\-\_OP\-\_drop}&0x13&0 & \\
1147 \livelink{chap:DWOPover}{DW\-\_OP\-\_over}&0x14&0 & \\
1148 \livelink{chap:DWOPpick}{DW\-\_OP\-\_pick}&0x15&1&1\dash byte stack index \\
1149 \livelink{chap:DWOPswap}{DW\-\_OP\-\_swap}&0x16&0 & \\
1150 \livelink{chap:DWOProt}{DW\-\_OP\-\_rot}&0x17&0 & \\
1151 \livelink{chap:DWOPxderef}{DW\-\_OP\-\_xderef}&0x18&0 & \\
1152 \livelink{chap:DWOPabs}{DW\-\_OP\-\_abs}&0x19&0 & \\
1153 \livelink{chap:DWOPand}{DW\-\_OP\-\_and}&0x1a&0 & \\
1154 \livelink{chap:DWOPdiv}{DW\-\_OP\-\_div}&0x1b&0 & \\
1158 \livelink{chap:DWOPminus}{DW\-\_OP\-\_minus}&0x1c&0 & \\
1159 \livelink{chap:DWOPmod}{DW\-\_OP\-\_mod}&0x1d&0 & \\
1160 \livelink{chap:DWOPmul}{DW\-\_OP\-\_mul}&0x1e&0 & \\
1161 \livelink{chap:DWOPneg}{DW\-\_OP\-\_neg}&0x1f&0 & \\
1162 \livelink{chap:DWOPnot}{DW\-\_OP\-\_not}&0x20&0 & \\
1163 \livelink{chap:DWOPor}{DW\-\_OP\-\_or}&0x21&0 & \\
1164 \livelink{chap:DWOPplus}{DW\-\_OP\-\_plus}&0x22&0 & \\
1165 \livelink{chap:DWOPplusuconst}{DW\-\_OP\-\_plus\-\_uconst}&0x23&1&ULEB128 addend \\
1166 \livelink{chap:DWOPshl}{DW\-\_OP\-\_shl}&0x24&0 & \\
1167 \livelink{chap:DWOPshr}{DW\-\_OP\-\_shr}&0x25&0 & \\
1168 \livelink{chap:DWOPshra}{DW\-\_OP\-\_shra}&0x26&0 & \\
1169 \livelink{chap:DWOPxor}{DW\-\_OP\-\_xor}&0x27&0 & \\
1170 \livelink{chap:DWOPskip}{DW\-\_OP\-\_skip}&0x2f&1&signed 2\dash byte constant \\
1171 \livelink{chap:DWOPbra}{DW\-\_OP\-\_bra}&0x28&1 & signed 2\dash byte constant \\
1172 \livelink{chap:DWOPeq}{DW\-\_OP\-\_eq}&0x29&0 & \\
1173 \livelink{chap:DWOPge}{DW\-\_OP\-\_ge}&0x2a&0 & \\
1174 \livelink{chap:DWOPgt}{DW\-\_OP\-\_gt}&0x2b&0 & \\
1175 \livelink{chap:DWOPle}{DW\-\_OP\-\_le}&0x2c&0 & \\
1176 \livelink{chap:DWOPlt}{DW\-\_OP\-\_lt}&0x2d&0 & \\
1177 \livelink{chap:DWOPne}{DW\-\_OP\-\_ne}&0x2e&0 & \\ \hline
1181 \livelink{chap:DWOPlit0}{DW\-\_OP\-\_lit0}&0x30 & 0 & \\
1183 \livelink{chap:DWOPlit1}{DW\-\_OP\-\_lit1}&0x31 & 0& literals 0 .. 31 = \\
1184 \ldots & & & (\livelink{chap:DWOPlit0}{DW\-\_OP\-\_lit0} + literal) \\
1185 \livelink{chap:DWOPlit31}{DW\-\_OP\-\_lit31}&0x4f & 0 & \\ \hline
1187 \livelink{chap:DWOPreg0}{DW\-\_OP\-\_reg0} & 0x50 & 0 & \\
1188 \livelink{chap:DWOPreg1}{DW\-\_OP\-\_reg1} & 0x51 & 0® 0 .. 31 = \\
1189 \ldots & & & (\livelink{chap:DWOPreg0}{DW\-\_OP\-\_reg0} + regnum) \\
1190 \livelink{chap:DWOPreg31}{DW\-\_OP\-\_reg31} & 0x6f & 0 & \\ \hline
1192 \livelink{chap:DWOPbreg0}{DW\-\_OP\-\_breg0} & 0x70 &1 & SLEB128 offset \\
1193 \livelink{chap:DWOPbreg1}{DW\-\_OP\-\_breg1} & 0x71 & 1 &base register 0 .. 31 = \\
1194 ... & & &(\livelink{chap:DWOPbreg0}{DW\-\_OP\-\_breg0} + regnum) \\
1195 \livelink{chap:DWOPbreg31}{DW\-\_OP\-\_breg31} & 0x8f & 1 & \\ \hline
1197 \livelink{chap:DWOPregx}{DW\-\_OP\-\_regx} & 0x90 &1&ULEB128 register \\
1198 \livelink{chap:DWOPfbreg}{DW\-\_OP\-\_fbreg} & 0x91&1&SLEB128 offset \\
1199 \livelink{chap:DWOPbregx}{DW\-\_OP\-\_bregx} & 0x92&2 &ULEB128 register followed \\
1200 & & & by SLEB128 offset \\
1201 \livelink{chap:DWOPpiece}{DW\-\_OP\-\_piece} & 0x93 &1& ULEB128 size of piece addressed \\
1202 \livelink{chap:DWOPderefsize}{DW\-\_OP\-\_deref\-\_size} & 0x94 &1& 1-byte size of data retrieved \\
1203 \livelink{chap:DWOPxderefsize}{DW\-\_OP\-\_xderef\-\_size} & 0x95&1&1-byte size of data retrieved \\
1204 \livelink{chap:DWOPnop}{DW\-\_OP\-\_nop} & 0x96 &0& \\
1207 \livelink{chap:DWOPpushobjectaddress}{DW\-\_OP\-\_push\-\_object\-\_address}&0x97&0 & \\
1208 \livelink{chap:DWOPcall2}{DW\-\_OP\-\_call2}&0x98&1& 2\dash byte offset of DIE \\
1209 \livelink{chap:DWOPcall4}{DW\-\_OP\-\_call4}&0x99&1& 4\dash byte offset of DIE \\
1210 \livelink{chap:DWOPcallref}{DW\-\_OP\-\_call\-\_ref}&0x9a&1& 4\dash\ or 8\dash byte\\
1211 &&& offset of DIE \\
1212 \livelink{chap:DWOPformtlsaddress}{DW\-\_OP\-\_form\-\_tls\-\_address}&0x9b &0& \\
1213 \livelink{chap:DWOPcallframecfa}{DW\-\_OP\-\_call\-\_frame\-\_cfa} &0x9c &0& \\
1214 \livelink{chap:DWOPbitpiece}{DW\-\_OP\-\_bit\-\_piece}&0x9d &2&ULEB128 size followed by \\
1216 \livelink{chap:DWOPimplicitvalue}{DW\-\_OP\-\_implicit\-\_value}&0x9e &2&ULEB128 size followed by \\
1217 &&&block of that size\\
1218 \livelink{chap:DWOPstackvalue}{DW\-\_OP\-\_stack\-\_value} &0x9f &0& \\
1219 \livetarg{chap:DWOPlouser}{DW\-\_OP\-\_lo\-\_user} &0xe0 && \\
1220 \livetarg{chap:DWOPhiuser}{DW\-\_OP\-\_hi\-\_user} &0xff && \\
1226 \subsection{Location Descriptions}
1227 \label{datarep:locationdescriptions}
1229 A location description is used to compute the
1230 location of a variable or other entity.
1232 \subsection{Location Lists}
1233 \label{datarep:locationlists}
1235 Each entry in a location list is either a location list entry,
1236 a base address selection entry, or an end of list entry.
1238 A location list entry consists of two address offsets followed
1239 by a 2\dash byte length, followed by a block of contiguous bytes
1240 that contains a DWARF location description. The length
1241 specifies the number of bytes in that block. The two offsets
1242 are the same size as an address on the target machine.
1244 A base address selection entry and an end of list entry each
1245 consist of two (constant or relocated) address offsets. The two
1246 offsets are the same size as an address on the target machine.
1248 For a location list to be specified, the base address of
1249 the corresponding compilation unit must be defined
1250 (see Section \refersec{chap:normalandpartialcompilationunitentries}).
1252 \section{Base Type Attribute Encodings}
1253 \label{datarep:basetypeattributeencodings}
1255 The encodings of the constants used in the \livelink{chap:DWATencoding}{DW\-\_AT\-\_encoding}
1256 attribute are given in
1257 Table \refersec{tab:basetypeencodingvalues}
1260 \setlength{\extrarowheight}{0.1cm}
1261 \begin{longtable}{l|c}
1262 \caption{Base type encoding values} \label{tab:basetypeencodingvalues} \\
1263 \hline \\ \bfseries Base type encoding code name&\bfseries Value \\ \hline
1265 \bfseries Base type encoding code name&\bfseries Value\\ \hline
1267 \hline \emph{Continued on next page}
1272 \livelink{chap:DWATEaddress}{DW\-\_ATE\-\_address}&0x01 \\
1273 \livelink{chap:DWATEboolean}{DW\-\_ATE\-\_boolean}&0x02 \\
1274 \livelink{chap:DWATEcomplexfloat}{DW\-\_ATE\-\_complex\-\_float}&0x03 \\
1275 \livelink{chap:DWATEfloat}{DW\-\_ATE\-\_float}&0x04 \\
1276 \livelink{chap:DWATEsigned}{DW\-\_ATE\-\_signed}&0x05 \\
1277 \livelink{chap:DWATEsignedchar}{DW\-\_ATE\-\_signed\-\_char}&0x06 \\
1278 \livelink{chap:DWATEunsigned}{DW\-\_ATE\-\_unsigned}&0x07 \\
1279 \livelink{chap:DWATEunsignedchar}{DW\-\_ATE\-\_unsigned\-\_char}&0x08 \\
1280 \livelink{chap:DWATEimaginaryfloat}{DW\-\_ATE\-\_imaginary\-\_float}&0x09 \\
1281 \livelink{chap:DWATEpackeddecimal}{DW\-\_ATE\-\_packed\-\_decimal}&0x0a \\
1282 \livelink{chap:DWATEnumericstring}{DW\-\_ATE\-\_numeric\-\_string}&0x0b \\
1283 \livelink{chap:DWATEedited}{DW\-\_ATE\-\_edited}&0x0c \\
1284 \livelink{chap:DWATEsignedfixed}{DW\-\_ATE\-\_signed\-\_fixed}&0x0d \\
1285 \livelink{chap:DWATEunsignedfixed}{DW\-\_ATE\-\_unsigned\-\_fixed}&0x0e \\
1286 \livelink{chap:DWATEdecimalfloat}{DW\-\_ATE\-\_decimal\-\_float} & 0x0f \\
1287 \livelink{chap:DWATEUTF}{DW\-\_ATE\-\_UTF} \ddag & 0x10 \\
1288 \livetarg{chap:DWATElouser}{DW\-\_ATE\-\_lo\-\_user} & 0x80 \\
1289 \livetarg{chap:DWATEhiuser}{DW\-\_ATE\-\_hi\-\_user} & 0xff \\
1292 \ddag Base type encoding new in DWARF Version 4
1296 The encodings of the constants used in the
1297 \livelink{chap:DWATdecimalsign}{DW\-\_AT\-\_decimal\-\_sign} attribute
1299 Table \refersec{tab:decimalsignencodings}.
1303 \setlength{\extrarowheight}{0.1cm}
1304 \begin{longtable}{l|c}
1305 \caption{Decimal sign encodings} \label{tab:decimalsignencodings} \\
1306 \hline \\ \bfseries Decimal sign code name&\bfseries Value \\ \hline
1308 \bfseries Decimal sign code name&\bfseries Value\\ \hline
1310 \hline \emph{Continued on next page}
1315 \livelink{chap:DWDSunsigned}{DW\-\_DS\-\_unsigned} & 0x01 \\
1316 \livelink{chap:DWDSleadingoverpunch}{DW\-\_DS\-\_leading\-\_overpunch} & 0x02 \\
1317 \livelink{chap:DWDStrailingoverpunch}{DW\-\_DS\-\_trailing\-\_overpunch} & 0x03 \\
1318 \livelink{chap:DWDSleadingseparate}{DW\-\_DS\-\_leading\-\_separate} & 0x04 \\
1319 \livelink{chap:DWDStrailingseparate}{DW\-\_DS\-\_trailing\-\_separate} & 0x05 \\
1324 The encodings of the constants used in the
1325 \livelink{chap:DWATendianity}{DW\-\_AT\-\_endianity} attribute are given in
1326 Table \refersec{tab:endianityencodings}.
1329 \setlength{\extrarowheight}{0.1cm}
1330 \begin{longtable}{l|c}
1331 \caption{Endianity encodings} \label{tab:endianityencodings}\\
1332 \hline \\ \bfseries Endian code name&\bfseries Value \\ \hline
1334 \bfseries Endian code name&\bfseries Value\\ \hline
1336 \hline \emph{Continued on next page}
1341 \livelink{chap:DWENDdefault}{DW\-\_END\-\_default} & 0x00 \\
1342 \livelink{chap:DWENDbig}{DW\-\_END\-\_big} & 0x01 \\
1343 \livelink{chap:DWENDlittle}{DW\-\_END\-\_little} & 0x02 \\
1344 \livetarg{chap:DWENDlouser}{DW\-\_END\-\_lo\-\_user} & 0x40 \\
1345 \livetarg{chap:DWENDhiuser}{DW\-\_END\-\_hi\-\_user} & 0xff \\
1350 \section{Accessibility Codes}
1351 \label{datarep:accessibilitycodes}
1352 The encodings of the constants used in the \livelink{chap:DWATaccessibility}{DW\-\_AT\-\_accessibility}
1353 attribute are given in
1354 Table \refersec{tab:accessibilityencodings}.
1357 \setlength{\extrarowheight}{0.1cm}
1358 \begin{longtable}{l|c}
1359 \caption{Accessibility encodings} \label{tab:accessibilityencodings}\\
1360 \hline \\ \bfseries Accessibility code name&\bfseries Value \\ \hline
1362 \bfseries Accessibility code name&\bfseries Value\\ \hline
1364 \hline \emph{Continued on next page}
1369 \livelink{chap:DWACCESSpublic}{DW\-\_ACCESS\-\_public}&0x01 \\
1370 \livelink{chap:DWACCESSprotected}{DW\-\_ACCESS\-\_protected}&0x02 \\
1371 \livelink{chap:DWACCESSprivate}{DW\-\_ACCESS\-\_private}&0x03 \\
1377 \section{Visibility Codes}
1378 \label{datarep:visibilitycodes}
1379 The encodings of the constants used in the
1380 \livelink{chap:DWATvisibility}{DW\-\_AT\-\_visibility} attribute are given in
1381 Table \refersec{tab:visibilityencodings}.
1384 \setlength{\extrarowheight}{0.1cm}
1385 \begin{longtable}{l|c}
1386 \caption{Visibility encodings} \label{tab:visibilityencodings}\\
1387 \hline \\ \bfseries Visiibility code name&\bfseries Value \\ \hline
1389 \bfseries Visibility code name&\bfseries Value\\ \hline
1391 \hline \emph{Continued on next page}
1396 \livelink{chap:DWVISlocal}{DW\-\_VIS\-\_local}&0x01 \\
1397 \livelink{chap:DWVISexported}{DW\-\_VIS\-\_exported}&0x02 \\
1398 \livelink{chap:DWVISqualified}{DW\-\_VIS\-\_qualified}&0x03 \\
1403 \section{Virtuality Codes}
1404 \label{datarep:vitualitycodes}
1406 The encodings of the constants used in the
1407 \livelink{chap:DWATvirtuality}{DW\-\_AT\-\_virtuality} attribute are given in
1408 Table \refersec{tab:virtualityencodings}.
1411 \setlength{\extrarowheight}{0.1cm}
1412 \begin{longtable}{l|c}
1413 \caption{Virtuality encodings} \label{tab:virtualityencodings}\\
1414 \hline \\ \bfseries Virtuality code name&\bfseries Value \\ \hline
1416 \bfseries Virtuality code name&\bfseries Value\\ \hline
1418 \hline \emph{Continued on next page}
1423 \livelink{chap:DWVIRTUALITYnone}{DW\-\_VIRTUALITY\-\_none}&0x00 \\
1424 \livelink{chap:DWVIRTUALITYvirtual}{DW\-\_VIRTUALITY\-\_virtual}&0x01 \\
1425 \livelink{chap:DWVIRTUALITYpurevirtual}{DW\-\_VIRTUALITY\-\_pure\-\_virtual}&0x02 \\
1433 \livelink{chap:DWVIRTUALITYnone}{DW\-\_VIRTUALITY\-\_none} is equivalent to the absence of the
1434 \livelink{chap:DWATvirtuality}{DW\-\_AT\-\_virtuality}
1437 \section{Source Languages}
1438 \label{datarep:sourcelanguages}
1440 The encodings of the constants used in the \livelink{chap:DWATlanguage}{DW\-\_AT\-\_language}
1441 attribute are given in
1442 Table \refersec{tab:languageencodings}.
1444 % If we don't force a following space it looks odd
1446 and their associated values are reserved, but the
1447 languages they represent are not well supported.
1448 Table \refersec{tab:languageencodings}
1449 also shows the default lower bound, if any, assumed for
1450 an omitted \livelink{chap:DWATlowerbound}{DW\-\_AT\-\_lower\-\_bound} attribute in the context of a
1451 \livelink{chap:DWTAGsubrangetype}{DW\-\_TAG\-\_subrange\-\_type} debugging information entry for each
1455 \setlength{\extrarowheight}{0.1cm}
1456 \begin{longtable}{l|c|c}
1457 \caption{Language encodings} \label{tab:languageencodings}\\
1458 \hline \\ \bfseries Language name&\bfseries Value &\bfseries Default Lower Bound \\ \hline
1460 \bfseries Language name&\bfseries Value &\bfseries Default Lower Bound\\ \hline
1462 \hline \emph{Continued on next page}
1467 \livelink{chap:DWLANGC89}{DW\-\_LANG\-\_C89}&0x0001&0 \\
1468 \livelink{chap:DWLANGC}{DW\-\_LANG\-\_C}&0x0002&0 \\
1469 \livelink{chap:DWLANGAda83}{DW\-\_LANG\-\_Ada83} \dag &0x0003&1 \\
1470 \livelink{chap:DWLANGCplusplus}{DW\-\_LANG\-\_C\-\_plus\-\_plus} &0x0004&0 \\
1471 \livelink{chap:DWLANGCobol74}{DW\-\_LANG\-\_Cobol74} \dag &0x0005&1 \\
1472 \livelink{chap:DWLANGCobol85}{DW\-\_LANG\-\_Cobol85} \dag &0x0006&1 \\
1473 \livelink{chap:DWLANGFortran77}{DW\-\_LANG\-\_Fortran77}&0x0007&1 \\
1474 \livelink{chap:DWLANGFortran90}{DW\-\_LANG\-\_Fortran90}&0x0008&1 \\
1475 \livelink{chap:DWLANGPascal83}{DW\-\_LANG\-\_Pascal83}&0x0009&1 \\
1476 \livelink{chap:DWLANGModula2}{DW\-\_LANG\-\_Modula2}&0x000a&1 \\
1477 \livelink{chap:DWLANGJava}{DW\-\_LANG\-\_Java}&0x000b&0 \\
1478 \livelink{chap:DWLANGC99}{DW\-\_LANG\-\_C99}&0x000c&0 \\
1479 \livelink{chap:DWLANGAda95}{DW\-\_LANG\-\_Ada95} \dag &0x000d&1 \\
1480 \livelink{chap:DWLANGFortran95}{DW\-\_LANG\-\_Fortran95} &0x000e&1 \\
1481 \livelink{chap:DWLANGPLI}{DW\-\_LANG\-\_PLI} \dag &0x000f&1 \\
1482 \livelink{chap:DWLANGObjC}{DW\-\_LANG\-\_ObjC}&0x0010&0 \\
1483 \livelink{chap:DWLANGObjCplusplus}{DW\-\_LANG\-\_ObjC\-\_plus\-\_plus}&0x0011&0 \\
1484 \livelink{chap:DWLANGUPC}{DW\-\_LANG\-\_UPC}&0x0012&0 \\
1485 \livelink{chap:DWLANGD}{DW\-\_LANG\-\_D}&0x0013&0 \\
1486 \livelink{chap:DWLANGPython}{DW\-\_LANG\-\_Python} \dag &0x0014&0 \\
1487 \livetarg{chap:DWLANGlouser}{DW\-\_LANG\-\_lo\-\_user}&0x8000 & \\
1488 \livetarg{chap:DWLANGhiuser}{DW\-\_LANG\-\_hi\-\_user}&0xffff & \\
1494 \section{Address Class Encodings}
1495 \label{datarep:addressclassencodings}
1497 The value of the common address class encoding
1498 \livelink{chap:DWADDRnone}{DW\-\_ADDR\-\_none} is 0.
1501 \section{Identifier Case}
1502 \label{datarep:identifiercase}
1504 The encodings of the constants used in the
1505 \livelink{chap:DWATidentifiercase}{DW\-\_AT\-\_identifier\-\_case} attribute are given in
1506 Table \refersec{tab:identifiercaseencodings}.
1509 \setlength{\extrarowheight}{0.1cm}
1510 \begin{longtable}{l|c}
1511 \caption{Identifier case encodings} \label{tab:identifiercaseencodings}\\
1512 \hline \\ \bfseries Identifier case name&\bfseries Value \\ \hline
1514 \bfseries Identifier case name&\bfseries Value\\ \hline
1516 \hline \emph{Continued on next page}
1520 \livelink{chap:DWIDcasesensitive}{DW\-\_ID\-\_case\-\_sensitive}&0x00 \\
1521 \livelink{chap:DWIDupcase}{DW\-\_ID\-\_up\-\_case}&0x01 \\
1522 \livelink{chap:DWIDdowncase}{DW\-\_ID\-\_down\-\_case}&0x02 \\
1523 \livelink{chap:DWIDcaseinsensitive}{DW\-\_ID\-\_case\-\_insensitive}&0x03 \\
1527 \section{Calling Convention Encodings}
1528 \label{datarep:callingconventionencodings}
1529 The encodings of the constants used in the
1530 \livelink{chap:DWATcallingconvention}{DW\-\_AT\-\_calling\-\_convention} attribute are given in
1531 Table \refersec{tab:callingconventionencodings}.
1534 \setlength{\extrarowheight}{0.1cm}
1535 \begin{longtable}{l|c}
1536 \caption{Calling convention encodings} \label{tab:callingconventionencodings}\\
1537 \hline \\ \bfseries Calling Convention name&\bfseries Value \\ \hline
1539 \bfseries Calling Convention name&\bfseries Value\\ \hline
1541 \hline \emph{Continued on next page}
1546 \livelink{chap:DWCCnormal}{DW\-\_CC\-\_normal}&0x01 \\
1547 \livelink{chap:DWCCprogram}{DW\-\_CC\-\_program}&0x02 \\
1548 \livelink{chap:DWCCnocall}{DW\-\_CC\-\_nocall}&0x03 \\
1549 \livetarg{chap:DWCClouser}{DW\-\_CC\-\_lo\-\_user}&0x40 \\
1550 \livetarg{chap:DWCChiuser}{DW\-\_CC\-\_hi\-\_user}&0xff \\
1555 \section{Inline Codes}
1556 \label{datarep:inlinecodes}
1558 The encodings of the constants used in the
1559 \livelink{chap:DWATinline}{DW\-\_AT\-\_inline} attribute are given in
1560 Table \refersec{tab:inlineencodings}.
1563 \setlength{\extrarowheight}{0.1cm}
1564 \begin{longtable}{l|c}
1565 \caption{Inline encodings} \label{tab:inlineencodings}\\
1566 \hline \\ \bfseries Iline Code name&\bfseries Value \\ \hline
1568 \bfseries Iline Code name&\bfseries Value\\ \hline
1570 \hline \emph{Continued on next page}
1575 \livelink{chap:DWINLnotinlined}{DW\-\_INL\-\_not\-\_inlined}&0x00 \\
1576 \livelink{chap:DWINLinlined}{DW\-\_INL\-\_inlined}&0x01 \\
1577 \livelink{chap:DWINLdeclarednotinlined}{DW\-\_INL\-\_declared\-\_not\-\_inlined}&0x02 \\
1578 \livelink{chap:DWINLdeclaredinlined}{DW\-\_INL\-\_declared\-\_inlined}&0x03 \\
1583 % this clearpage is ugly, but the following table came
1584 % out oddly without it.
1586 \section{Array Ordering}
1587 \label{datarep:arrayordering}
1589 The encodings of the constants used in the
1590 \livelink{chap:DWATordering}{DW\-\_AT\-\_ordering} attribute are given in
1591 Table \refersec{tab:orderingencodings}.
1594 \setlength{\extrarowheight}{0.1cm}
1595 \begin{longtable}{l|c}
1596 \caption{Ordering encodings} \label{tab:orderingencodings}\\
1597 \hline \\ \bfseries Ordering name&\bfseries Value \\ \hline
1599 \bfseries Ordering name&\bfseries Value\\ \hline
1601 \hline \emph{Continued on next page}
1606 \livelink{chap:DWORDrowmajor}{DW\-\_ORD\-\_row\-\_major}&0x00 \\
1607 \livelink{chap:DWORDcolmajor}{DW\-\_ORD\-\_col\-\_major}&0x01 \\
1613 \section{Discriminant Lists}
1614 \label{datarep:discriminantlists}
1616 The descriptors used in the
1617 \livelink{chap:DWATdiscrlist}{DW\-\_AT\-\_discr\-\_list} attribute are
1618 encoded as 1\dash byte constants. The
1619 defined values are given in
1620 Table \refersec{tab:discriminantdescriptorencodings}.
1622 % Odd that the 'Name' field captalized here, it is not caps elsewhere.
1624 \setlength{\extrarowheight}{0.1cm}
1625 \begin{longtable}{l|c}
1626 \caption{Discriminant descriptor encodings} \label{tab:discriminantdescriptorencodings}\\
1627 \hline \\ \bfseries Descriptor Name&\bfseries Value \\ \hline
1629 \bfseries Descriptor Name&\bfseries Value\\ \hline
1631 \hline \emph{Continued on next page}
1636 \livetarg{chap:DWDSClabel}{DW\-\_DSC\-\_label}&0x00 \\
1637 \livetarg{chap:DWDSCrange}{DW\-\_DSC\-\_range}&0x01 \\
1642 \section{Name Lookup Tables}
1643 \label{datarep:namelookuptables}
1645 Each set of entries in the table of global names contained
1646 in the .debug\_pubnames and .debug\_pubtypes sections begins
1647 with a header consisting of:
1650 \begin{enumerate}[1.]
1651 \item unit\_length (initial length) \\
1652 A 4\dash byte or 12\dash byte unsigned integer representing the length
1653 of the .debug\_info contribution for that compilation unit,
1654 not including the length field itself. In the 32\dash bit DWARF
1655 format, this is a 4\dash byte unsigned integer (which must be less
1656 than 0xfffffff0); in the 64\dash bit DWARF format, this consists
1657 of the 4\dash byte value 0xffffffff followed by an 8\dash byte unsigned
1658 integer that gives the actual length
1659 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
1661 \item version (uhalf)
1662 A 2\dash byte unsigned integer representing the version of the
1663 DWARF information for the compilation unit
1664 (see Appendix \refersec{app:dwarfsectionversionnumbersinformative}).
1665 The value in this field is 4.
1667 % Some say unsigned offset this just says offset: FIXME
1668 \item debug\_info\_offset (section offset) \\
1669 A 4\dash byte or 8\dash byte offset into the .debug\_info
1670 section of the compilation unit header.
1672 the 32\dash bit DWARF format, this is a 4\dash byte unsigned offset;
1673 in the 64\dash bit DWARF format, this is an 8\dash byte unsigned offsets
1674 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
1676 \item debug\_info\_length (section length) \\
1677 A 4\dash byte or 8\dash byte length containing the size in bytes of the
1678 contents of the .debug\_info section generated to represent
1679 this compilation unit. In the 32\dash bit DWARF format, this is
1680 a 4\dash byte unsigned length; in the 64\dash bit DWARF format, this
1681 is an 8-byte unsigned length
1682 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
1687 This header is followed by a series of tuples. Each tuple
1688 consists of a 4\dash byte or 8\dash byte offset followed by a string
1689 of non\dash null bytes terminated by one null byte.
1691 DWARF format, this is a 4\dash byte offset; in the 64\dash bit DWARF
1692 format, it is an 8\dash byte offset.
1693 Each set is terminated by an
1694 offset containing the value 0.
1697 \section{Address Range Table}
1698 \label{datarep:addrssrangetable}
1700 Each set of entries in the table of address ranges contained
1701 in the .debug\_aranges section begins with a header containing:
1703 \begin{enumerate}[1.]
1704 % FIXME The unit length text is not fully consistent across
1707 \item unit\_length (initial length) \\
1708 A 4-byte or 12-byte length containing the length of the
1709 set of entries for this compilation unit, not including the
1710 length field itself. In the 32-bit DWARF format, this is a
1711 4-byte unsigned integer (which must be less than 0xfffffff0);
1712 in the 64-bit DWARF format, this consists of the 4-byte value
1713 0xffffffff followed by an 8-byte unsigned integer that gives
1715 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
1717 \item version (uhalf) \\
1718 A 2\dash byte version identifier containing the value 2
1719 (see Appendix \refersec{app:dwarfsectionversionnumbersinformative}).
1721 \item debug\_info\_offset (section offset) \\
1722 A 4\dash byte or 8\dash byte offset into the .debug\_info section of
1723 the compilation unit header. In the 32\dash bit DWARF format,
1724 this is a 4\dash byte unsigned offset; in the 64\dash bit DWARF format,
1725 this is an 8\dash byte unsigned offset
1726 (see Section \refersec{datarep:32bitand64bitdwarfformats}).
1728 \item address\_size (ubyte) \\
1729 A 1\dash byte unsigned integer containing the size in bytes of an
1730 address (or the offset portion of an address for segmented
1731 addressing) on the target system.
1733 \item segment\_size (ubyte) \\
1734 A 1\dash byte unsigned integer containing the size in bytes of a
1735 segment selector on the target system.
1739 This header is followed by a series of tuples. Each tuple
1740 consists of a segment, an address and a length.
1742 size is given by the segment\_size field of the header; the
1743 address and length size are each given by the address\_size
1744 field of the header.
1745 The first tuple following the header in
1746 each set begins at an offset that is a multiple of the size
1747 of a single tuple (that is, the size of a segment selector
1748 plus twice the size of an address).
1749 The header is padded, if
1750 necessary, to that boundary. Each set of tuples is terminated
1751 by a 0 for the segment, a 0 for the address and 0 for the
1752 length. If the segment\_size field in the header is zero,
1753 the segment selectors are omitted from all tuples, including
1754 the terminating tuple.
1757 \section{Line Number Information}
1758 \label{datarep:linenumberinformation}
1760 The version number in the line number program header is 4
1761 (see Appendix \refersec{app:dwarfsectionversionnumbersinformative}).
1763 The boolean values ``true'' and ``false''
1764 used by the line number information program are encoded
1765 as a single byte containing the value 0
1766 for ``false,'' and a non-zero value for ``true.''
1768 The encodings for the standard opcodes are given in
1769 Table \refersec{tab:linenumberstandardopcodeencodings}.
1771 % Odd that the 'Name' field captalized here, it is not caps elsewhere.
1773 \setlength{\extrarowheight}{0.1cm}
1774 \begin{longtable}{l|c}
1775 \caption{Line Number Standard Opcode encodings} \label{tab:linenumberstandardopcodeencodings}\\
1776 \hline \\ \bfseries Opcode Name&\bfseries Value \\ \hline
1778 \bfseries Opcode Name&\bfseries Value\\ \hline
1780 \hline \emph{Continued on next page}
1785 \livelink{chap:DWLNScopy}{DW\-\_LNS\-\_copy}&0x01 \\
1786 \livelink{chap:DWLNSadvancepc}{DW\-\_LNS\-\_advance\-\_pc}&0x02 \\
1787 \livelink{chap:DWLNSadvanceline}{DW\-\_LNS\-\_advance\-\_line}&0x03 \\
1788 \livelink{chap:DWLNSsetfile}{DW\-\_LNS\-\_set\-\_file}&0x04 \\
1789 \livelink{chap:DWLNSsetcolumn}{DW\-\_LNS\-\_set\-\_column}&0x05 \\
1790 \livelink{chap:DWLNSnegatestmt}{DW\-\_LNS\-\_negate\-\_stmt}&0x06 \\
1791 \livelink{chap:DWLNSsetbasicblock}{DW\-\_LNS\-\_set\-\_basic\-\_block}&0x07 \\
1792 \livelink{chap:DWLNSconstaddpc}{DW\-\_LNS\-\_const\-\_add\-\_pc}*0x08 \\
1793 \livelink{chap:DWLNSfixedadvancepc}{DW\-\_LNS\-\_fixed\-\_advance\-\_pc}&0x09 \\
1794 \livelink{chap:DWLNSsetprologueend}{DW\-\_LNS\-\_set\-\_prologue\-\_end}&0x0a \\
1795 \livelink{chap:DWLNSsetepiloguebegin}{DW\-\_LNS\-\_set\-\_epilogue\-\_begin}&0x0b \\
1796 \livelink{chap:DWLNSsetisa}{DW\-\_LNS\-\_set\-\_isa}&0x0c \\
1802 The encodings for the extended opcodes are given in
1803 Table \refersec{tab:linenumberextendedopcodeencodings}.
1806 \setlength{\extrarowheight}{0.1cm}
1807 \begin{longtable}{l|c}
1808 \caption{Line Number Extended Opcode encodings} \label{tab:linenumberextendedopcodeencodings}\\
1809 \hline \\ \bfseries Opcode Name&\bfseries Value \\ \hline
1811 \bfseries Opcode Name&\bfseries Value\\ \hline
1813 \hline \emph{Continued on next page}
1818 \livelink{chap:DWLNEendsequence}{DW\-\_LNE\-\_end\-\_sequence}&0x01 \\
1819 \livelink{chap:DWLNEsetaddress}{DW\-\_LNE\-\_set\-\_address}&0x02\\
1820 \livelink{chap:DWLNEdefinefile}{DW\-\_LNE\-\_define\-\_file}&0x03\\
1821 \livelink{chap:DWLNEsetdiscriminator}{DW\-\_LNE\-\_set\-\_discriminator} \ddag &0x04 \\
1822 \livetarg{chap:DWLNElouser}{DW\-\_LNE\-\_lo\-\_user}&0x80 \\
1823 \livetarg{chap:DWLNEhiuser}{DW\-\_LNE\-\_hi\-\_user}&0xff \\
1826 \ddag Extended opcode new in DWARF Version 4.
1829 \section{Macro Information}
1830 \label{datarep:macroinformation}
1832 The source line numbers and source file indices encoded in the
1833 macro information section are represented as unsigned LEB128
1834 numbers as are the constants in a \livelink{chap:DWMACINFOvendorext}{DW\-\_MACINFO\-\_vendor\-\_ext} entry.
1836 The macinfo type is encoded as a single byte.
1837 The encodings are given in
1838 Table \refersec{tab:macinfotypeencodings}.
1842 \setlength{\extrarowheight}{0.1cm}
1843 \begin{longtable}{l|c}
1844 \caption{Macinfo Type Encodings} \label{tab:macinfotypeencodings}\\
1845 \hline \\ \bfseries Macinfo Type Name&\bfseries Value \\ \hline
1847 \bfseries Macinfo Type Name&\bfseries Value\\ \hline
1849 \hline \emph{Continued on next page}
1854 \livelink{chap:DWMACINFOdefine}{DW\-\_MACINFO\-\_define}&0x01 \\
1855 \livelink{chap:DWMACINFOundef}{DW\-\_MACINFO\-\_undef}&0x02 \\
1856 \livelink{chap:DWMACINFOstartfile}{DW\-\_MACINFO\-\_start\-\_file}&0x03 \\
1857 \livelink{chap:DWMACINFOendfile}{DW\-\_MACINFO\-\_end\-\_file}&0x04 \\
1858 \livelink{chap:DWMACINFOvendorext}{DW\-\_MACINFO\-\_vendor\-\_ext}&0xff \\
1863 \section{Call Frame Information}
1864 \label{datarep:callframeinformation}
1866 In the 32\dash bit DWARF format, the value of the CIE id in the
1867 CIE header is 0xffffffff; in the 64\dash bit DWARF format, the
1868 value is 0xffffffffffffffff.
1870 The value of the CIE version number is 4
1871 (see Appendix \refersec{app:dwarfsectionversionnumbersinformative}).
1873 Call frame instructions are encoded in one or more bytes. The
1874 primary opcode is encoded in the high order two bits of
1875 the first byte (that is, opcode = byte >> 6). An operand
1876 or extended opcode may be encoded in the low order 6
1877 bits. Additional operands are encoded in subsequent bytes.
1878 The instructions and their encodings are presented in
1879 Table \refersec{tab:callframeinstructionencodings}.
1882 \setlength{\extrarowheight}{0.1cm}
1883 \begin{longtable}{l|c|c|l|l}
1884 \caption{Call frame instruction encodings} \label{tab:callframeinstructionencodings} \\
1885 \hline \\ &\bfseries High 2 &\bfseries Low 6 & & \\
1886 \bfseries Instruction&\bfseries Bits &\bfseries Bits &\bfseries Operand 1 &\bfseries Operand 2\\ \hline
1888 & \bfseries High 2 &\bfseries Low 6 & &\\
1889 \bfseries Instruction&\bfseries Bits &\bfseries Bits &\bfseries Operand 1 &\bfseries Operand 2\\ \hline
1891 \hline \emph{Continued on next page}
1896 \livelink{chap:DWCFAadvanceloc}{DW\-\_CFA\-\_advance\-\_loc}&0x1&delta & \\
1897 \livelink{chap:DWCFAoffset}{DW\-\_CFA\-\_offset}&0x2®ister&ULEB128 offset \\
1898 \livelink{chap:DWCFArestore}{DW\-\_CFA\-\_restore}&0x3®ister & & \\
1899 \livelink{chap:DWCFAnop}{DW\-\_CFA\-\_nop}&0&0 & & \\
1900 \livelink{chap:DWCFAsetloc}{DW\-\_CFA\-\_set\-\_loc}&0&0x01&address & \\
1901 \livelink{chap:DWCFAadvanceloc1}{DW\-\_CFA\-\_advance\-\_loc1}&0&0x02&1\dash byte delta & \\
1902 \livelink{chap:DWCFAadvanceloc2}{DW\-\_CFA\-\_advance\-\_loc2}&0&0x03&2\dash byte delta & \\
1903 \livelink{chap:DWCFAadvanceloc4}{DW\-\_CFA\-\_advance\-\_loc4}&0&0x04&4\dash byte delta & \\
1904 \livelink{chap:DWCFAoffsetextended}{DW\-\_CFA\-\_offset\-\_extended}&0&0x05&ULEB128 register&ULEB128 offset \\
1905 \livelink{chap:DWCFArestoreextended}{DW\-\_CFA\-\_restore\-\_extended}&0&0x06&ULEB128 register & \\
1906 \livelink{chap:DWCFAundefined}{DW\-\_CFA\-\_undefined}&0&0x07&ULEB128 register & \\
1907 \livelink{chap:DWCFAsamevalue}{DW\-\_CFA\-\_same\-\_value}&0&0x08 &ULEB128 register & \\
1908 \livelink{chap:DWCFAregister}{DW\-\_CFA\-\_register}&0&0x09&ULEB128 register &ULEB128 offset \\
1909 \livelink{chap:DWCFArememberstate}{DW\-\_CFA\-\_remember\-\_state}&0&0x0a & & \\
1910 \livelink{chap:DWCFArestorestate}{DW\-\_CFA\-\_restore\-\_state}&0&0x0b & & \\
1911 \livelink{chap:DWCFAdefcfa}{DW\-\_CFA\-\_def\-\_cfa}&0&0x0c &ULEB128 register&ULEB128 offset \\
1912 \livelink{chap:DWCFAdefcfaregister}{DW\-\_CFA\-\_def\-\_cfa\-\_register}&0&0x0d&ULEB128 register & \\
1913 \livelink{chap:DWCFAdefcfaoffset}{DW\-\_CFA\-\_def\-\_cfa\-\_offset}&0&0x0e &ULEB128 offset & \\
1914 \livelink{chap:DWCFAdefcfaexpression}{DW\-\_CFA\-\_def\-\_cfa\-\_expression}&0&0x0f &BLOCK \\
1915 \livelink{chap:DWCFAexpression}{DW\-\_CFA\-\_expression}&0&0x10&ULEB128 register & BLOCK \\
1917 \livelink{chap:DWCFAoffsetextendedsf}{DW\-\_CFA\-\_offset\-\_extended\-\_sf}&0&0x11&ULEB128 register&SLEB128 offset \\
1918 \livelink{chap:DWCFAdefcfasf}{DW\-\_CFA\-\_def\-\_cfa\-\_sf}&0&0x12&ULEB128 register&SLEB128 offset \\
1919 \livelink{chap:DWCFAdefcfaoffsetsf}{DW\-\_CFA\-\_def\-\_cfa\-\_offset\-\_sf}&0&0x13&SLEB128 offset & \\
1920 \livelink{chap:DWCFAvaloffset}{DW\-\_CFA\-\_val\-\_offset}&0&0x14&ULEB128&ULEB128 \\
1921 \livelink{chap:DWCFAvaloffsetsf}{DW\-\_CFA\-\_val\-\_offset\-\_sf}&0&0x15&ULEB128&SLEB128 \\
1922 \livelink{chap:DWCFAvalexpression}{DW\-\_CFA\-\_val\-\_expression}&0&0x16&ULEB128&BLOCK \\
1923 \livetarg{chap:DWCFAlouser}{DW\-\_CFA\-\_lo\-\_user}&0&0x1c & & \\
1924 \livetarg{chap:DWCFAhiuser}{DW\-\_CFA\-\_hi\-\_user}&0&0x3f & & \\
1928 \section{Non-continguous Address Ranges}
1929 \label{datarep:noncontiguousaddressranges}
1931 Each entry in a range list
1932 (see Section \refersec{chap:noncontiguousaddressranges})
1934 range list entry, a base address selection entry, or an end
1937 A range list entry consists of two relative addresses. The
1938 addresses are the same size as addresses on the target machine.
1940 A base address selection entry and an end of list entry each
1941 consist of two (constant or relocated) addresses. The two
1942 addresses are the same size as addresses on the target machine.
1944 For a range list to be specified, the base address of the
1945 corresponding compilation unit must be defined
1946 (see Section \refersec{chap:normalandpartialcompilationunitentries}).
1949 \section{Dependencies and Constraints}
1950 \label{datarep:dependenciesandconstraints}
1952 The debugging information in this format is intended to
1953 exist in the .debug\_abbrev, .debug\_aranges, .debug\_frame,
1954 .debug\_info, .debug\_line, .debug\_loc, .debug\_macinfo,
1955 .debug\_pubnames, .debug\_pubtypes, .debug\_ranges, .debug\_str
1956 and .debug\_types sections of an object file, or equivalent
1957 separate file or database. The information is not
1958 word\dash aligned. Consequently: •
1961 \item For the 32\dash bit DWARF format and a target architecture with
1962 32\dash bit addresses, an assembler or compiler must provide a way
1963 to produce 2\dash byte and 4\dash byte quantities without alignment
1964 restrictions, and the linker must be able to relocate a
1965 4\dash byte address or section offset that occurs at an arbitrary
1968 \item For the 32\dash bit DWARF format and a target architecture with
1969 64\dash bit addresses, an assembler or compiler must provide a
1970 way to produce 2\dash byte, 4\dash byte and 8\dash byte quantities without
1971 alignment restrictions, and the linker must be able to relocate
1972 an 8\dash byte address or 4\dash byte section offset that occurs at an
1973 arbitrary alignment.
1975 \item For the 64\dash bit DWARF format and a target architecture with
1976 32\dash bit addresses, an assembler or compiler must provide a
1977 way to produce 2\dash byte, 4\dash byte and 8\dash byte quantities without
1978 alignment restrictions, and the linker must be able to relocate
1979 a 4\dash byte address or 8\dash byte section offset that occurs at an
1980 arbitrary alignment.
1982 \textit{It is expected that this will be required only for very large
1983 32\dash bit programs or by those architectures which support
1984 a mix of 32\dash bit and 64\dash bit code and data within the same
1987 \item For the 64\dash bit DWARF format and a target architecture with
1988 64\dash bit addresses, an assembler or compiler must provide a
1989 way to produce 2\dash byte, 4\dash byte and 8\dash byte quantities without
1990 alignment restrictions, and the linker must be able to
1991 relocate an 8\dash byte address or section offset that occurs at
1992 an arbitrary alignment.
1995 \section{Integer Representation Names}
1996 \label{datarep:integerrepresentationnames}
1998 The sizes of the integers used in the lookup by name, lookup
1999 by address, line number and call frame information sections
2001 Table 41 \refersec{tab:integerrepresentationnames}.
2004 \setlength{\extrarowheight}{0.1cm}
2005 \begin{longtable}{c|l}
2006 \caption{Integer Representation Names} \label{tab:integerrepresentationnames}\\
2007 \hline \\ \bfseries Representation Name&\bfseries Representation \\ \hline
2009 \bfseries Representation Name&\bfseries Representation\\ \hline
2011 \hline \emph{Continued on next page}
2016 sbyte& signed, 1\dash byte integer \\
2017 ubyte&unsigned, 1\dash byte integer \\
2018 uhalf&unsigned, 2\dash byte integer \\
2019 uword&unsigned, 4\dash byte integer \\
2024 \section{Type Signature Computation}
2025 \label{datarep:typesignaturecomputation}
2027 A type signature is computed only by the DWARF producer;
2028 it is used by a DWARF consumer to resolve type references to
2029 the type definitions that are contained in type units.
2031 The type signature for a type T0 is formed from the MD5
2032 hash of a flattened description of the type. The flattened
2033 description of the type is a byte sequence derived from the
2034 DWARF encoding of the type as follows:
2036 \begin{enumerate}[1.]
2038 \item Start with an empty sequence S and a list V of visited
2039 types, where V is initialized to a list containing the type
2040 T0 as its single element. Elements in V are indexed from 1,
2043 \item If the debugging information entry represents a type that
2044 is nested inside another type or a namespace, append to S
2045 the type’s context as follows: For each surrounding type
2046 or namespace, beginning with the outermost such construct,
2047 append the letter 'C', the DWARF tag of the construct, and
2048 the name (taken from the \livelink{chap:DWATname}{DW\-\_AT\-\_name} attribute) of the type
2049 or namespace (including its trailing null byte).
2051 \item Append to S the letter 'D', followed by the DWARF tag of
2052 the debugging information entry.
2054 \item For each of the following attributes that are present in
2055 the debugging information entry, in the order listed below,
2056 append to S a marker letter (see below), the DWARF attribute
2057 code, and the attribute value.
2060 \item \livelink{chap:DWATname}{DW\-\_AT\-\_name}
2061 \item \livelink{chap:DWATaccessibility}{DW\-\_AT\-\_accessibility}
2062 \item \livelink{chap:DWATaddressclass}{DW\-\_AT\-\_address\-\_class}
2063 \item \livelink{chap:DWATallocated}{DW\-\_AT\-\_allocated}
2064 \item \livelink{chap:DWATartificial}{DW\-\_AT\-\_artificial}
2065 \item \livelink{chap:DWATassociated}{DW\-\_AT\-\_associated}
2066 \item \livelink{chap:DWATbinaryscale}{DW\-\_AT\-\_binary\-\_scale}
2067 \item \livelink{chap:DWATbitoffset}{DW\-\_AT\-\_bit\-\_offset}
2068 \item \livelink{chap:DWATbitsize}{DW\-\_AT\-\_bit\-\_size}
2069 \item \livelink{chap:DWATbitstride}{DW\-\_AT\-\_bit\-\_stride}
2070 \item \livelink{chap:DWATbytesize}{DW\-\_AT\-\_byte\-\_size}
2071 \item \livelink{chap:DWATbytestride}{DW\-\_AT\-\_byte\-\_stride}
2072 \item \livelink{chap:DWATconstexpr}{DW\-\_AT\-\_const\-\_expr}
2073 \item \livelink{chap:DWATconstvalue}{DW\-\_AT\-\_const\-\_value}
2074 \item \livelink{chap:DWATcontainingtype}{DW\-\_AT\-\_containing\-\_type}
2075 \item \livelink{chap:DWATcount}{DW\-\_AT\-\_count}
2076 \item \livelink{chap:DWATdatabitoffset}{DW\-\_AT\-\_data\-\_bit\-\_offset}
2077 \item \livelink{chap:DWATdatalocation}{DW\-\_AT\-\_data\-\_location}
2078 \item \livelink{chap:DWATdatamemberlocation}{DW\-\_AT\-\_data\-\_member\-\_location}
2079 \item \livelink{chap:DWATdecimalscale}{DW\-\_AT\-\_decimal\-\_scale}
2080 \item \livelink{chap:DWATdecimalsign}{DW\-\_AT\-\_decimal\-\_sign}
2081 \item \livelink{chap:DWATdefaultvalue}{DW\-\_AT\-\_default\-\_value}
2082 \item \livelink{chap:DWATdigitcount}{DW\-\_AT\-\_digit\-\_count}
2083 \item \livelink{chap:DWATdiscr}{DW\-\_AT\-\_discr}
2084 \item \livelink{chap:DWATdiscrlist}{DW\-\_AT\-\_discr\-\_list}
2085 \item \livelink{chap:DWATdiscrvalue}{DW\-\_AT\-\_discr\-\_value}
2086 \item \livelink{chap:DWATencoding}{DW\-\_AT\-\_encoding}
2087 \item \livelink{chap:DWATenumclass}{DW\-\_AT\-\_enum\-\_class}
2088 \item \livelink{chap:DWATendianity}{DW\-\_AT\-\_endianity}
2089 \item \livelink{chap:DWATexplicit}{DW\-\_AT\-\_explicit}
2090 \item \livelink{chap:DWATisoptional}{DW\-\_AT\-\_is\-\_optional}
2091 \item \livelink{chap:DWATlocation}{DW\-\_AT\-\_location}
2092 \item \livelink{chap:DWATlowerbound}{DW\-\_AT\-\_lower\-\_bound}
2093 \item \livelink{chap:DWATmutable}{DW\-\_AT\-\_mutable}
2094 \item \livelink{chap:DWATordering}{DW\-\_AT\-\_ordering}
2095 \item \livelink{chap:DWATpicturestring}{DW\-\_AT\-\_picture\-\_string}
2096 \item \livelink{chap:DWATprototyped}{DW\-\_AT\-\_prototyped}
2097 \item \livelink{chap:DWATsmall}{DW\-\_AT\-\_small}
2098 \item \livelink{chap:DWATsegment}{DW\-\_AT\-\_segment}
2099 \item \livelink{chap:DWATstringlength}{DW\-\_AT\-\_string\-\_length}
2100 \item \livelink{chap:DWATthreadsscaled}{DW\-\_AT\-\_threads\-\_scaled}
2101 \item \livelink{chap:DWATupperbound}{DW\-\_AT\-\_upper\-\_bound}
2102 \item \livelink{chap:DWATuselocation}{DW\-\_AT\-\_use\-\_location}
2103 \item \livelink{chap:DWATuseUTF8}{DW\-\_AT\-\_use\-\_UTF8}
2104 \item \livelink{chap:DWATvariableparameter}{DW\-\_AT\-\_variable\-\_parameter}
2105 \item \livelink{chap:DWATvirtuality}{DW\-\_AT\-\_virtuality}
2106 \item \livelink{chap:DWATvisibility}{DW\-\_AT\-\_visibility}
2107 \item \livelink{chap:DWATvtableelemlocation}{DW\-\_AT\-\_vtable\-\_elem\-\_location}
2110 Note that except for the initial \livelink{chap:DWATname}{DW\-\_AT\-\_name} attribute,
2111 attributes are appended in order according to the alphabetical
2112 spelling of their identifier.
2114 If an implementation defines any vendor-specific attributes,
2115 any such attributes that are essential to the definition of
2116 the type should also be included at the end of the above list,
2117 in their own alphabetical suborder.
2119 An attribute that refers to another type entry T is processed
2120 as follows: (a) If T is in the list V at some V[x], use the
2121 letter 'R' as the marker and use the unsigned LEB128 encoding
2122 of x as the attribute value; otherwise, (b) use the letter 'T'
2123 as the marker, process the type T recursively by performing
2124 Steps 2 through 7, and use the result as the attribute value.
2126 Other attribute values use the letter 'A' as the marker, and
2127 the value consists of the form code (encoded as an unsigned
2128 LEB128 value) followed by the encoding of the value according
2129 to the form code. To ensure reproducibility of the signature,
2130 the set of forms used in the signature computation is limited
2131 to the following: \livelink{chap:DWFORMsdata}{DW\-\_FORM\-\_sdata},
2132 \livelink{chap:DWFORMflag}{DW\-\_FORM\-\_flag},
2133 \livelink{chap:DWFORMstring}{DW\-\_FORM\-\_string},
2134 and \livelink{chap:DWFORMblock}{DW\-\_FORM\-\_block}.
2136 \item If the tag in Step 3 is one of \livelink{chap:DWTAGpointertype}{DW\-\_TAG\-\_pointer\-\_type},
2137 \livelink{chap:DWTAGreferencetype}{DW\-\_TAG\-\_reference\-\_type},
2138 \livelink{chap:DWTAGrvaluereferencetype}{DW\-\_TAG\-\_rvalue\-\_reference\-\_type},
2139 \livelink{chap:DWTAGptrtomembertype}{DW\-\_TAG\-\_ptr\-\_to\-\_member\-\_type},
2140 or \livelink{chap:DWTAGfriend}{DW\-\_TAG\-\_friend}, and the referenced
2141 type (via the \livelink{chap:DWATtype}{DW\-\_AT\-\_type} or
2142 \livelink{chap:DWATfriend}{DW\-\_AT\-\_friend} attribute) has a
2143 \livelink{chap:DWATname}{DW\-\_AT\-\_name} attribute, append to S the letter 'N', the DWARF
2144 attribute code (\livelink{chap:DWATtype}{DW\-\_AT\-\_type} or
2145 \livelink{chap:DWATfriend}{DW\-\_AT\-\_friend}), the context of
2146 the type (according to the method in Step 2), the letter 'E',
2147 and the name of the type. For \livelink{chap:DWTAGfriend}{DW\-\_TAG\-\_friend}, if the referenced
2148 entry is a \livelink{chap:DWTAGsubprogram}{DW\-\_TAG\-\_subprogram}, the context is omitted and the
2149 name to be used is the ABI-specific name of the subprogram
2150 (e.g., the mangled linker name).
2153 \item 6.If the tag in Step 3 is not one of \livelink{chap:DWTAGpointertype}{DW\-\_TAG\-\_pointer\-\_type},
2154 \livelink{chap:DWTAGreferencetype}{DW\-\_TAG\-\_reference\-\_type},
2155 \livelink{chap:DWTAGrvaluereferencetype}{DW\-\_TAG\-\_rvalue\-\_reference\-\_type},
2156 \livelink{chap:DWTAGptrtomembertype}{DW\-\_TAG\-\_ptr\-\_to\-\_member\-\_type}, or
2157 \livelink{chap:DWTAGfriend}{DW\-\_TAG\-\_friend}, but has
2158 a \livelink{chap:DWATtype}{DW\-\_AT\-\_type} attribute, or if the referenced type (via
2159 the \livelink{chap:DWATtype}{DW\-\_AT\-\_type} or
2160 \livelink{chap:DWATfriend}{DW\-\_AT\-\_friend} attribute) does not have a
2161 \livelink{chap:DWATname}{DW\-\_AT\-\_name} attribute, the attribute is processed according to
2162 the method in Step 4 for an attribute that refers to another
2166 \item Visit each child C of the debugging information
2167 entry as follows: If C is a nested type entry or a member
2168 function entry, and has a \livelink{chap:DWATname}{DW\-\_AT\-\_name} attribute, append to
2169 S the letter 'S', the tag of C, and its name; otherwise,
2170 process C recursively by performing Steps 3 through 7,
2171 appending the result to S. Following the last child (or if
2172 there are no children), append a zero byte.
2177 For the purposes of this algorithm, if a debugging information
2179 \livelink{chap:DWATspecification}{DW\-\_AT\-\_specification}
2180 attribute that refers to
2181 another entry D (which has a
2182 \livelink{chap:DWATdeclaration}{DW\-\_AT\-\_declaration}
2184 then S inherits the attributes and children of D, and S is
2185 processed as if those attributes and children were present in
2186 the entry S. Exception: if a particular attribute is found in
2187 both S and D, the attribute in S is used and the corresponding
2188 one in D is ignored.
2190 DWARF tag and attribute codes are appended to the sequence
2191 as unsigned LEB128 values, using the values defined earlier
2194 \textit{A grammar describing this computation may be found in
2195 Appendix \refersec{app:typesignaturecomputationgrammar}.
2198 \textit{An attribute that refers to another type entry should
2199 be recursively processed or replaced with the name of the
2200 referent (in Step 4, 5 or 6). If neither treatment applies to
2201 an attribute that references another type entry, the entry
2202 that contains that attribute should not be considered for a
2203 separate type unit.}
2205 \textit{If a debugging information entry contains an attribute from
2206 the list above that would require an unsupported form, that
2207 entry should not be considered for a separate type unit.}
2209 \textit{A type should be considered for a separate type unit only
2210 if all of the type entries that it contains or refers to in
2211 Steps 6 and 7 can themselves each be considered for a separate
2214 Where the DWARF producer may reasonably choose two or more
2215 different forms for a given attribute, it should choose
2216 the simplest possible form in computing the signature. (For
2217 example, a constant value should be preferred to a location
2218 expression when possible.)
2220 Once the string S has been formed from the DWARF encoding,
2221 an MD5 hash is computed for the string and the lower 64 bits
2222 are taken as the type signature.
2224 \textit{The string S is intended to be a flattened representation of
2225 the type that uniquely identifies that type (i.e., a different
2226 type is highly unlikely to produce the same string).}
2228 \textit{A debugging information entry should not be placed in a
2229 separate type unit if any of the following apply:}
2233 \item \textit{The entry has an attribute whose value is a location
2234 expression, and the location expression contains a reference to
2235 another debugging information entry (e.g., a \livelink{chap:DWOPcallref}{DW\-\_OP\-\_call\-\_ref}
2236 operator), as it is unlikely that the entry will remain
2237 identical across compilation units.}
2239 \item \textit{The entry has an attribute whose value refers
2240 to a code location or a location list.}
2242 \item \textit{The entry has an attribute whose value refers
2243 to another debugging information entry that does not represent
2248 \textit{Certain attributes are not included in the type signature:}
2251 \item \textit{The \livelink{chap:DWATdeclaration}{DW\-\_AT\-\_declaration} attribute is not included because it
2252 indicates that the debugging information entry represents an
2253 incomplete declaration, and incomplete declarations should
2254 not be placed in separate type units.}
2256 \item \textit{The \livelink{chap:DWATdescription}{DW\-\_AT\-\_description} attribute is not included because
2257 it does not provide any information unique to the defining
2258 declaration of the type.}
2260 \item \textit{The \livelink{chap:DWATdeclfile}{DW\-\_AT\-\_decl\-\_file}, \livelink{chap:DWATdeclline}{DW\-\_AT\-\_decl\-\_line}, and
2261 \livelink{chap:DWATdeclcolumn}{DW\-\_AT\-\_decl\-\_column} attributes are not included because they
2262 may vary from one source file to the next, and would prevent
2263 two otherwise identical type declarations from producing the