1 \chapter{Program Scope Entries}
2 \label{chap:programscopeentries}
3 This section describes debugging information entries that
4 relate to different levels of program scope: compilation,
5 module, subprogram, and so on. Except for separate type
6 entries (see Section \refersec{chap:separatetypeunitentries}),
7 these entries may be thought of
8 as bounded by ranges of text addresses within the program.
10 \section{Unit Entries}
11 An object file may contain one or more compilation units,
13 \addtoindexx{unit|see {compilation unit, partial unit \textit{or} type unit}}
14 \addtoindexx{compilation unit}
16 \addtoindexx{normal compilation unit}
17 \addtoindexx{normal compilation unit|see {compilation unit}}
18 normal compilation units,
19 partial compilation units and
20 \addtoindexx{type unit}
22 \addtoindex{partial compilation unit}
23 is related to one or more other compilation units that
25 \addtoindex{type unit} represents
26 a single complete type in a
27 separate unit. Either a normal compilation unit or a
28 \addtoindex{partial compilation unit}
29 may be logically incorporated into another
30 compilation unit using an
31 \addtoindex{imported unit entry}.
34 \subsection[Normal and Partial CU Entries]{Normal and Partial Compilation Unit Entries}
35 \label{chap:normalandpartialcompilationunitentries}
37 A \addtoindex{normal compilation unit} is represented by a debugging
38 information entry with the
39 tag \DWTAGcompileunitTARG.
40 A \addtoindex{partial compilation unit} is represented by a debugging information
42 tag \DWTAGpartialunitTARG.
44 In a simple normal compilation, a single compilation unit with
46 \DWTAGcompileunit{} represents a complete object file
48 \DWTAGpartialunit{} is not used.
50 employing the DWARF space compression and duplicate elimination
52 Appendix \refersec{app:usingcompilationunits},
53 multiple compilation units using
55 \DWTAGcompileunit{} and/or
56 \DWTAGpartialunit{} are
57 used to represent portions of an object file.
59 \textit{A normal compilation unit typically represents the text and
60 data contributed to an executable by a single relocatable
61 object file. It may be derived from several source files,
62 including pre\dash processed \doublequote{include files.}
63 A \addtoindex{partial compilation unit} typically represents a part of the text
64 and data of a relocatable object file, in a manner that can
65 potentially be shared with the results of other compilations
66 to save space. It may be derived from an \doublequote{include file,}
67 template instantiation, or other implementation\dash dependent
68 portion of a compilation. A normal compilation unit can also
69 function in a manner similar to a partial compilation unit
72 A compilation unit entry owns debugging information
73 entries that represent all or part of the declarations
74 made in the corresponding compilation. In the case of a
75 partial compilation unit, the containing scope of its owned
76 declarations is indicated by imported unit entries in one
77 or more other compilation unit entries that refer to that
78 partial compilation unit (see
79 Section \refersec{chap:importedunitentries}).
82 Compilation unit entries may have the following
84 \begin{enumerate}[1. ]
85 \item Either a \DWATlowpc{} and
87 \addtoindexx{high PC attribute}
89 \addtoindexx{low PC attribute}
91 \addtoindexx{ranges attribute}
93 \DWATranges{} attribute
94 \addtoindexx{ranges attribute}
96 \addtoindexx{discontiguous address ranges|see{non-contiguous address ranges}}
99 non\dash contiguous address ranges, respectively,
100 of the machine instructions generated for the compilation
101 unit (see Section \refersec{chap:codeaddressesandranges}).
103 A \DWATlowpc{} attribute
107 \addtoindexx{ranges attribute}
109 \DWATranges{} to specify the
110 \addtoindexx{ranges attribute}
111 default base address for use in
112 \addtoindexx{location list}
113 location lists (see Section
114 \refersec{chap:locationlists}) and range lists
115 \addtoindexx{range list}
116 (see Section \refersec{chap:noncontiguousaddressranges}).
118 \item A \DWATname{} attribute
119 \addtoindexx{name attribute}
120 whose value is a null\dash terminated
122 \hypertarget{chap:DWATnamepathnameofcompilationsource}{}
123 containing the full or relative path name of the primary
124 source file from which the compilation unit was derived.
126 \item A \DWATlanguage{} attribute
127 \addtoindexx{language attribute}
128 whose constant value is an
129 \hypertarget{chap:DWATlanguageprogramminglanguage}{}
131 \addtoindexx{language attribute}
132 indicating the source language of the compilation
133 unit. The set of language names and their meanings are given
134 in Table \refersec{tab:languagenames}.
138 \caption{Language names}
139 \label{tab:languagenames}
142 Language name & Meaning\\ \hline
143 \DWLANGAdaeightythreeTARG{} \dag & ISO \addtoindex{Ada}:1983 \addtoindexx{Ada} \\
144 \DWLANGAdaninetyfiveTARG{} \dag & ISO Ada:1995 \addtoindexx{Ada} \\
145 \DWLANGCTARG & Non-standardized C, such as K\&R \\
146 \DWLANGCeightynineTARG & ISO C:1989 \\
147 \DWLANGCninetynineTARG & ISO \addtoindex{C}:1999 \\
148 \DWLANGCplusplusTARG & ISO \addtoindex{C++}:1998 \\
149 \DWLANGCpluspluszerothreeTARG & ISO \addtoindex{C++}:2003 \\
150 \DWLANGCpluspluselevenTARG & ISO \addtoindex{C++}:2011 \\
151 \DWLANGCobolseventyfourTARG & ISO \addtoindex{COBOL}:1974 \\
152 \DWLANGCoboleightyfiveTARG & ISO \addtoindex{COBOL}:1985 \\
153 \DWLANGDTARG{} \dag & D \addtoindexx{D language} \\
154 \DWLANGFortranseventysevenTARG &ISO \addtoindex{FORTRAN} 77\\
155 \DWLANGFortranninetyTARG & ISO \addtoindex{Fortran 90}\\
156 \DWLANGFortranninetyfiveTARG & ISO \addtoindex{Fortran 95}\\
157 \DWLANGGoTARG{} \dag & \addtoindex{Go}\\
158 \DWLANGHaskellTARG{} \dag & \addtoindex{Haskell}\\
159 \DWLANGJavaTARG{} & \addtoindex{Java}\\
160 \DWLANGModulatwoTARG & ISO Modula\dash 2:1996 \addtoindexx{Modula-2}\\
161 \DWLANGModulathreeTARG & \addtoindex{Modula-3}\\
162 \DWLANGObjCTARG{} & \addtoindex{Objective C}\\
163 \DWLANGObjCplusplusTARG{} & \addtoindex{Objective C++}\\
164 \DWLANGOCamlTARG{} \dag & \addtoindex{OCaml}\index{Objective Caml|see{OCaml}}\\
165 \DWLANGOpenCLTARG{} \dag & \addtoindex{OpenCL}\\
166 \DWLANGPascaleightythreeTARG & ISO \addtoindex{Pascal}:1983\\
167 \DWLANGPLITARG{} \dag & ANSI \addtoindex{PL/I}:1976\\
168 \DWLANGPythonTARG{} \dag & \addtoindex{Python}\\
169 \DWLANGRustTARG{} \dag & \addtoindex{Rust} \\
170 \DWLANGUPCTARG{} & \addtoindex{Unified Parallel C}\addtoindexx{UPC}\\ \hline
171 \dag \ \ \textit{Support for these languages is limited.}& \\
175 \item A \DWATstmtlist{}
176 attribute whose value is
177 \addtoindexx{statement list attribute}
179 \addtoindexx{section offset!in statement list attribute}
181 \hypertarget{chap:DWATstmtlistlinenumberinformationforunit}{}
182 offset to the line number information for this compilation
185 This information is placed in a separate object file
186 section from the debugging information entries themselves. The
187 value of the statement list attribute is the offset in the
188 \dotdebugline{} section of the first byte of the line number
189 information for this compilation unit
190 (see Section \refersec{chap:linenumberinformation}).
195 \item A \DWATmacros{} attribute
196 \addtoindexx{macro information attribute}
198 \addtoindexx{section offset!in macro information attribute}
200 \hypertarget{chap:DWATmacrosmacroinformation}{}
201 offset to the macro information for this compilation unit.
203 This information is placed in a separate object file section
204 from the debugging information entries themselves. The
205 value of the macro information attribute is the offset in
206 the \dotdebugmacro{} section of the first byte of the macro
207 information for this compilation unit
208 (see Section \refersec{chap:macroinformation}).
210 \textit{The \DWATmacros{} attribute is new in \DWARFVersionV,
212 \DWATmacroinfo{} attribute of earlier DWARF versions.
213 \livetarg{chap:DWATmacroinfomacroinformation}{}
214 While \DWATmacros{} and \DWATmacroinfo{} attributes cannot both occur in the same
215 compilation unit, both may be found in the set of units that make up an executable
216 or shared object. The two attributes have distinct encodings to facilitate such
223 \hypertarget{chap:DWATcompdircompilationdirectory}{}
225 null\dash terminated string containing the current working directory
226 of the compilation command that produced this compilation
227 unit in whatever form makes sense for the host system.
229 \item A \DWATproducer{} attribute
230 \addtoindexx{producer attribute}
231 whose value is a null\dash
232 terminated string containing information about the compiler
233 \hypertarget{chap:DWATproducercompileridentification}{}
234 that produced the compilation unit. The actual contents of
235 the string will be specific to each producer, but should
236 begin with the name of the compiler vendor or some other
237 identifying character sequence that should avoid confusion
238 with other producer values.
241 \item A \DWATidentifiercase{}
243 \addtoindexx{identifier case attribute}
245 \hypertarget{chap:DWATidentifiercaseidentifiercaserule}{}
246 constant value is a code describing the treatment
247 of identifiers within this compilation unit. The
248 set of identifier case codes is given in
249 Table \refersec{tab:identifiercasecodes}.
251 \begin{simplenametable}{Identifier case codes}{tab:identifiercasecodes}
252 \DWIDcasesensitive{} \\
255 \DWIDcaseinsensitive{} \\
256 \end{simplenametable}
258 \DWIDcasesensitiveTARG{} is the default for all compilation units
259 that do not have this attribute. It indicates that names given
260 as the values of \DWATname{} attributes
261 \addtoindexx{name attribute}
262 in debugging information
263 entries for the compilation unit reflect the names as they
264 appear in the source program. The debugger should be sensitive
265 to the case of identifier names when doing identifier lookups.
268 \DWIDupcaseTARG{} means that the
269 producer of the debugging
270 information for this compilation unit converted all source
271 names to upper case. The values of the name attributes may not
272 reflect the names as they appear in the source program. The
273 debugger should convert all names to upper case when doing
276 \DWIDdowncaseTARG{} means that
277 the producer of the debugging
278 information for this compilation unit converted all source
279 names to lower case. The values of the name attributes may not
280 reflect the names as they appear in the source program. The
281 debugger should convert all names to lower case when doing
285 \DWIDcaseinsensitiveTARG{} means that the values of the name
286 attributes reflect the names as they appear in the source
287 program but that a case insensitive lookup should be used to
291 \item A \DWATbasetypes{} attribute whose value is a
292 \livelink{chap:classreference}{reference}.
295 \hypertarget{chap:DWATbasetypesprimitivedatatypesofcompilationunit}{}
297 \addtoindexx{base types attribute}
298 points to a debugging information entry
299 representing another compilation unit. It may be used
300 to specify the compilation unit containing the base type
301 entries used by entries in the current compilation unit
302 (see Section \refersec{chap:basetypeentries}).
305 This attribute provides a consumer a way to find the definition
306 of base types for a compilation unit that does not itself
307 contain such definitions. This allows a consumer, for example,
308 to interpret a type conversion to a base type
309 % getting this link target at the right spot is tricky.
310 \hypertarget{chap:DWATuseUTF8compilationunitusesutf8strings}{}
313 \item A \DWATuseUTFeight{} attribute,
314 \addtoindexx{use UTF8 attribute}\addtoindexx{UTF-8}
315 which is a \livelink{chap:classflag}{flag} whose
316 presence indicates that all strings (such as the names of
317 declared entities in the source program, or file names in the line table)
318 are represented using the UTF\dash 8 representation.
320 \item A \DWATmainsubprogram{} attribute, which is a \livelink{chap:classflag}{flag}
321 \addtoindexx{main subprogram attribute}
322 whose presence indicates
323 \hypertarget{chap:DWATmainsubprogramunitcontainingmainorstartingsubprogram}{}
324 that the compilation unit contains a
325 subprogram that has been identified as the starting function
326 of the program. If more than one compilation unit contains
327 this \nolink{flag}, any one of them may contain the starting function.
329 \textit{\addtoindex{Fortran} has a \addtoindex{PROGRAM statement}
331 to specify and provide a user\dash specified name for the main
332 subroutine of a program.
333 \addtoindex{C} uses the name \doublequote{main} to identify
334 the main subprogram of a program. Some other languages provide
335 similar or other means to identify the main subprogram of
338 \item A \DWATentrypc{} attribute whose value is the address of the first
339 \hypertarget{chap:DWATentrypcofcompileunit}{}
340 \hypertarget{chap:DWATentrypcofpartialunit}{}
341 \addtoindexx{entry pc attribute!for normal compilation unit}
342 \addtoindexx{entry pc attribute!for partial compilation unit}
343 executable instruction of the unit (see
344 Section \refersec{chap:entryaddress}).
346 \item A \DWATstroffsetsbaseNAME\addtoindexx{string offset base attribute}
347 \hypertarget{chap:DWATstroffsetbaseforindirectstringtable}{}
348 attribute, whose value is a reference.
349 This attribute points to the first string
350 offset of the compilation unit's contribution to the
351 \dotdebugstroffsets{} (or \dotdebugstroffsetsdwo{}) section.
352 Indirect string references
353 (using \DWFORMstrx) within the compilation unit are
354 interpreted as indices relative to this base.
357 \item A \DWATaddrbaseNAME\addtoindexx{address table base attribute}
358 \hypertarget{chap:DWATaddrbaseforaddresstable}{}
359 attribute, whose value is a reference.
360 This attribute points to the beginning of the compilation
361 unit's contribution to the \dotdebugaddr{} section.
362 Indirect references (using \DWFORMaddrx, \DWOPaddrx,
363 \DWOPconstx, \DWLLEbaseaddressselectionentry{},
364 \DWLLEstartendentry, or \DWLLEstartlengthentry) within the compilation unit are
365 interpreted as indices relative to this base.
368 \item A \DWATrangesbaseNAME\addtoindexx{ranges table base attribute}
369 \hypertarget{chap:DWATrangesbaseforrangelists}{}
370 attribute, whose value is a reference.
371 This attribute points to the beginning of the compilation
372 unit's contribution to the \dotdebugranges{} section.
373 References to range lists (using \DWFORMsecoffset)
374 within the compilation unit are
375 interpreted as offsets relative to this base.
380 The base address of a compilation unit is defined as the
381 value of the \DWATlowpc{} attribute, if present; otherwise,
382 it is undefined. If the base address is undefined, then any
383 DWARF entry or structure defined in terms of the base address
384 of that compilation unit is not valid.
386 \subsection{Skeleton Compilation Unit Entries}
387 \label{chap:skeletoncompilationunitentries}
388 When generating a split DWARF object (see
389 Section \refersec{datarep:splitdwarfobjects}), the
390 compilation unit in the \dotdebuginfo{} section is a "skeleton"
391 compilation unit, which contains only a subset of the
392 attributes of the full compilation unit. In general, it
393 contains those attributes that are necessary for the consumer
394 to locate the DWARF object where the full compilation unit
395 can be found, and for the consumer to interpret references to
396 addresses in the program.
398 A skeleton compilation unit has no
399 children, and may have the following attributes:
400 \begin{enumerate}[1. ]
403 Either a \DWATlowpc{} and \DWAThighpc{} pair of attributes
404 or a \DWATranges{} attribute (the same as for regular
405 compilation unit entries).
408 A \DWATstmtlist{} attribute (the same as for regular
409 compilation unit entries).
412 A \DWATcompdir{} attribute (the same as for regular
413 compilation unit entries).
416 \livetarg{chap:DWATdwonameforunit}{}
417 A \DWATdwonameNAME{} attribute whose value is a
418 null-terminated string containing the full or relative
419 path name of the DWARF object file that contains the full
423 \livetarg{chap:DWATdwoidforunit}{}
424 A \DWATdwoidNAME{} attribute whose value is an 8-byte
425 unsigned hash of the full compilation unit. This hash
426 value is computed by the method described in
427 Section \refersec{datarep:typesignaturecomputation}.
431 A \DWATuseUTFeight{} attribute (the same as for regular compilation unit
434 \textit{This attribute applies to strings referred to by the skeleton
435 compilation unit entry itself, and strings in the associated line
437 The representation for strings in the DWARF object file is determined
438 by the presence of a \DWATuseUTFeight{} attribute in the full compilation
442 A \DWATstroffsetsbase{} attribute, for indirect strings references
443 from the skeleton compilation unit (the same as for regular
444 compilation unit entries).
447 A \DWATaddrbase{} attribute (the same as for regular
448 compilation unit entries).
451 A \DWATrangesbase{} attribute (the same as for regular
452 compilation unit entries).
456 All other attributes of a compilation unit entry (described
457 in Section \refersec{chap:normalandpartialcompilationunitentries})
458 should be placed in the full compilation
459 unit entry in the \dotdebuginfodwo{} section of the split DWARF
460 object. The attributes provided by the skeleton compilation
461 unit entry do not need to be repeated in the full compilation
462 unit entry, except for \DWATdwoid, which should appear in
463 both entries so that the consumer can verify that it has
464 found the correct DWARF object.
467 \subsection{Imported Unit Entries}
468 \label{chap:importedunitentries}
470 \hypertarget{chap:DWATimportimportedunit}{}
471 place where a normal or partial unit is imported is
472 represented by a debugging information entry with the
473 \addtoindexx{imported unit entry}
474 tag \DWTAGimportedunitTARG.
475 An imported unit entry contains
476 \addtoindexx{import attribute}
478 \DWATimport{} attribute
479 whose value is a \livelink{chap:classreference}{reference} to the
480 normal or partial compilation unit whose declarations logically
481 belong at the place of the imported unit entry.
483 \textit{An imported unit entry does not necessarily correspond to
484 any entity or construct in the source program. It is merely
485 \doublequote{glue} used to relate a partial unit, or a compilation
486 unit used as a partial unit, to a place in some other
490 \subsection{Separate Type Unit Entries}
491 \label{chap:separatetypeunitentries}
492 An object file may contain any number of separate type
493 unit entries, each representing a single complete type
495 Each \addtoindex{type unit} must be uniquely identified by
496 a 64\dash bit signature, stored as part of the type unit, which
497 can be used to reference the type definition from debugging
498 information entries in other compilation units and type units.
500 A type unit is represented by a debugging information entry
501 with the tag \DWTAGtypeunitTARG.
502 A \addtoindex{type unit entry} owns debugging
503 information entries that represent the definition of a single
504 type, plus additional debugging information entries that may
505 be necessary to include as part of the definition of the type.
507 A type unit entry may have a
508 \DWATlanguage{} attribute,
510 \addtoindexx{language attribute}
511 constant value is an integer code indicating the source
512 language used to define the type. The set of language names
513 and their meanings are given in Table \refersec{tab:languagenames}.
515 A type unit entry may have a
516 \DWATstroffsetsbase\addtoindexx{string base offset attribute}
517 attribute, whose value is a reference. This attribute points
518 to the first string offset of the type unit's contribution to
519 the \dotdebugstroffsets{} section. Indirect string references
520 (using \DWFORMstrx) within the type unit must be interpreted
521 as indices relative to this base.
523 A type unit entry may have a \DWATstmtlist{} attribute, whose
524 value is a section offset to a line number table for this
525 type unit. Because type units do not describe any code, they
526 do not actually need a line number table, but the line number
527 tables also contain a list of directories and file names that
528 may be referenced by the \DWATdeclfile{} attribute. In a
529 normal object file with a regular compilation unit entry, the
530 type unit entries can simply refer to the line number table
531 used by the compilation unit. In a split DWARF object, where
532 the type units are located in a separate DWARF object file,
533 the \DWATstmtlist{} attribute refers to a "skeleton"
534 line number table in the \dotdebuglinedwo{} section, which
535 contains only the list of directories and file names. All
536 type unit entries in a split DWARF object may (but are not
537 required to) refer to the same skeleton line number table.
539 A type unit entry may have a \DWATuseUTFeight{} attribute, which is a flag
540 whose presence indicates that all strings referred to by this type
541 unit entry, its children, and the skeleton line number table, are
542 represented using the UTF-8 representation.
544 A \addtoindex{type unit} entry for a given type T owns a debugging
545 information entry that represents a defining declaration
546 of type T. If the type is nested within enclosing types or
547 namespaces, the debugging information entry for T is nested
548 within debugging information entries describing its containers;
549 otherwise, T is a direct child of the type unit entry.
551 A type unit entry may also own additional debugging information
552 entries that represent declarations of additional types that
553 are referenced by type T and have not themselves been placed in
554 separate type units. Like T, if an additional type U is nested
555 within enclosing types or namespaces, the debugging information
556 entry for U is nested within entries describing its containers;
557 otherwise, U is a direct child of the type unit entry.
559 The containing entries for types T and U are declarations,
560 and the outermost containing entry for any given type T or
561 U is a direct child of the type unit entry. The containing
562 entries may be shared among the additional types and between
563 T and the additional types.
565 \textit{Types are not required to be placed in type units. In general,
566 only large types such as structure, class, enumeration, and
567 union types included from header files should be considered
568 for separate type units. Base types and other small types
569 are not usually worth the overhead of placement in separate
570 type units. Types that are unlikely to be replicated, such
571 as those defined in the main source file, are also better
572 left in the main compilation unit.}
574 \section{Module, Namespace and Importing Entries}
575 \textit{Modules and namespaces provide a means to collect related
576 entities into a single entity and to manage the names of
579 \subsection{Module Entries}
580 \label{chap:moduleentries}
581 \textit{Several languages have the concept of a \doublequote{module.}
582 \addtoindexx{Modula-2}
583 A Modula\dash 2 definition module
584 \addtoindexx{Modula-2!definition module}
585 may be represented by a module
587 \addtoindex{declaration attribute}
588 (\DWATdeclaration). A
589 \addtoindex{Fortran 90} module
590 \addtoindexx{Fortran!module (Fortran 90)}
591 may also be represented by a module entry
592 (but no declaration attribute is warranted because \addtoindex{Fortran}
593 has no concept of a corresponding module body).}
595 A module is represented by a debugging information entry
597 tag \DWTAGmoduleTARG.
598 Module entries may own other
599 debugging information entries describing program entities
600 whose declaration scopes end at the end of the module itself.
602 If the module has a name, the module entry has a
603 \DWATname{} attribute
604 \addtoindexx{name attribute}
605 whose value is a null\dash terminated string containing
606 the module name as it appears in the source program.
608 The \addtoindex{module entry} may have either a
612 \addtoindexx{high PC attribute}
614 \addtoindexx{low PC attribute}
616 \DWATranges{} attribute
617 \addtoindexx{ranges attribute}
618 whose values encode the contiguous or non\dash contiguous address
619 ranges, respectively, of the machine instructions generated for
620 the module initialization code
621 (see Section \refersec{chap:codeaddressesandranges}).
622 \hypertarget{chap:DWATentrypcentryaddressofmoduleinitialization}{}
624 \addtoindexx{entry pc attribute!for module initialization}
626 \DWATentrypc{} attribute whose value is the address of
627 the first executable instruction of that initialization code
628 (see Section \refersec{chap:entryaddress}).
631 \hypertarget{chap:DWATprioritymodulepriority}{}
632 the module has been assigned a priority, it may have
633 \addtoindexx{priority attribute}
635 \DWATpriority{} attribute.
636 The value of this attribute is a
637 reference to another debugging information entry describing
638 a variable with a constant value. The value of this variable
639 is the actual constant value of the module\textquoteright s priority,
640 represented as it would be on the target architecture.
642 \subsection{Namespace Entries}
643 \label{chap:namespaceentries}
644 \textit{\addtoindex{C++} has the notion of a namespace, which provides a way to
645 \addtoindexx{namespace (C++)}
646 implement name hiding, so that names of unrelated things
647 do not accidentally clash in the
648 \addtoindex{global namespace} when an
649 application is linked together.}
651 A namespace is represented by a debugging information entry
653 tag \DWTAGnamespaceTARG.
654 A namespace extension is
655 \hypertarget{chap:DWATextensionpreviousnamespaceextensionororiginalnamespace}{}
657 \DWTAGnamespace{} entry
659 \addtoindexx{extension attribute}
662 attribute referring to the previous extension, or if there
663 is no previous extension, to the original
665 entry. A namespace extension entry does not need to duplicate
666 information in a previous extension entry of the namespace
667 nor need it duplicate information in the original namespace
668 entry. (Thus, for a namespace with a name,
669 a \DWATname{} attribute
670 \addtoindexx{name attribute}
671 need only be attached directly to the original
672 \DWTAGnamespace{} entry.)
675 Namespace and namespace extension entries may own
676 \addtoindexx{namespace extension entry}
678 \addtoindexx{namespace declaration entry}
679 debugging information entries describing program entities
680 whose declarations occur in the namespace.
682 \textit{For \addtoindex{C++}, such
683 owned program entities may be declarations,
684 including certain declarations that are also object or
685 function definitions.}
687 If a type, variable, or function declared in a namespace is
688 defined outside of the body of the namespace declaration,
689 that type, variable, or function definition entry has a
690 \DWATspecification{} attribute
691 \addtoindexx{specification attribute}
692 whose value is a \livelink{chap:classreference}{reference} to the
693 debugging information entry representing the declaration of
694 the type, variable or function. Type, variable, or function
696 \DWATspecification{} attribute
697 \addtoindexx{specification attribute}
699 to duplicate information provided by the declaration entry
700 referenced by the specification attribute.
702 \textit{The \addtoindex{C++} \addtoindex{global namespace}
704 \addtoindexx{global namespace|see{namespace (C++), global}}
706 \addtoindexx{namespace (C++)!global}
708 \texttt{::f}, for example) is not explicitly represented in
709 DWARF with a namespace entry (thus mirroring the situation
710 in \addtoindex{C++} source).
711 Global items may be simply declared with no
712 reference to a namespace.}
714 \textit{The \addtoindex{C++}
715 compilation unit specific \doublequote{unnamed namespace} may
716 \addtoindexx{namespace (C++)!unnamed}
717 \addtoindexx{unnamed namespace|see {namespace (C++), unnamed}}
718 be represented by a namespace entry with no name attribute in
719 the original namespace declaration entry (and therefore no name
720 attribute in any namespace extension entry of this namespace).
723 \textit{A compiler emitting namespace information may choose to
724 explicitly represent namespace extensions, or to represent the
725 final namespace declaration of a compilation unit; this is a
726 quality\dash of\dash implementation issue and no specific requirements
727 are given here. If only the final namespace is represented,
728 \addtoindexx{namespace (C++)!using declaration}
729 it is impossible for a debugger to interpret using declaration
730 references in exactly the manner defined by the
731 \addtoindex{C++} language.
734 \textit{Emitting all namespace declaration information in all
735 compilation units can result in a significant increase in the
736 size of the debug information and significant duplication of
737 information across compilation units.
738 The \addtoindex{C++} namespace std,
740 \addtoindexx{namespace (C++)!std}
741 is large and will probably be referenced in
742 every \addtoindex{C++} compilation unit.
745 \textit{For a \addtoindex{C++} namespace example,
746 see Appendix \refersec{app:namespaceexample}.
751 \subsection{Imported (or Renamed) Declaration Entries}
752 \label{chap:importedorrenameddeclarationentries}
753 \textit{Some languages support the concept of importing into or making
754 accessible in a given unit declarations made in a different
755 module or scope. An imported declaration may sometimes be
760 imported declaration is represented by one or
761 \addtoindexx{imported declaration entry}
762 more debugging information entries with the
763 tag \DWTAGimporteddeclarationTARG.
765 \hypertarget{chap:DWATimportimporteddeclaration}{}
767 is imported, there is one imported declaration entry for
769 \addtoindexx{import attribute}
770 Each imported declaration entry has a
771 \DWATimport{} attribute,
772 whose value is a \livelink{chap:classreference}{reference} to the
773 debugging information entry representing the declaration that
776 An imported declaration may also have a
779 \addtoindexx{name attribute}
780 whose value is a null\dash terminated string containing the
781 name, as it appears in the source program, by which the
782 imported entity is to be known in the context of the imported
783 declaration entry (which may be different than the name of
784 the entity being imported). If no name is present, then the
785 name by which the entity is to be known is the same as the
786 name of the entity being imported.
788 An imported declaration entry with a name attribute may be
789 used as a general means to rename or provide an alias for
790 \addtoindexx{alias declaration|see{imported declaration entry}}
791 an entity, regardless of the context in which the importing
792 declaration or the imported entity occurs.
794 \textit{A \addtoindex{C++} namespace alias may be represented by an imported
795 \hypertarget{chap:DWATimportnamespacealias}{}
797 \addtoindexx{namespace (C++)!alias}
798 with a name attribute whose value is
799 a null\dash terminated string containing the alias name as it
800 appears in the source program and an import attribute whose
801 value is a \livelink{chap:classreference}{reference} to the applicable original namespace or
802 namespace extension entry.
805 \textit{A \addtoindex{C++} using declaration may be represented by one or more
806 \hypertarget{chap:DWATimportnamespaceusingdeclaration}{}
808 \addtoindexx{namespace (C++)!using declaration}
809 declaration entries. When the using declaration
810 refers to an overloaded function, there is one imported
811 declaration entry corresponding to each overloading. Each
812 imported declaration entry has no name attribute but it does
813 have an import attribute that refers to the entry for the
814 entity being imported. (\addtoindex{C++}
815 provides no means to \doublequote{rename}
816 an imported entity, other than a namespace).
819 \textit{A \addtoindex{Fortran} use statement
820 \addtoindexx{Fortran!use statement}
821 \addtoindexx{use statement|see {Fortran, use statement}}
822 with an \doublequote{only list} may be
823 represented by a series of imported declaration entries,
824 one (or more) for each entity that is imported. An entity
825 \addtoindexx{renamed declaration|see{imported declaration entry}}
826 that is renamed in the importing context may be represented
827 by an imported declaration entry with a name attribute that
828 specifies the new local name.
831 \subsection{Imported Module Entries}
832 \label{chap:importedmoduleentries}
834 \textit{Some languages support the concept of importing into or making
835 accessible in a given unit all of the declarations contained
836 within a separate module or namespace.
839 An imported module declaration is represented by a debugging
840 information entry with
841 \addtoindexx{imported module attribute}
843 \addtoindexx{imported module entry}
844 tag \DWTAGimportedmoduleTARG.
846 imported module entry contains a
847 \DWATimport{} attribute
848 \addtoindexx{import attribute}
849 whose value is a \livelink{chap:classreference}{reference}
850 to the module or namespace entry
851 containing the definition and/or declaration entries for
852 the entities that are to be imported into the context of the
853 imported module entry.
855 An imported module declaration may own a set of imported
856 declaration entries, each of which refers to an entry in the
857 module whose corresponding entity is to be known in the context
858 of the imported module declaration by a name other than its
859 name in that module. Any entity in the module that is not
860 renamed in this way is known in the context of the imported
861 module entry by the same name as it is declared in the module.
863 \textit{A \addtoindex{C++} using directive
864 \addtoindexx{namespace (C++)!using directive}
865 \addtoindexx{using directive|see {namespace (C++), using directive}}
866 may be represented by an imported module
867 \hypertarget{chap:DWATimportnamespaceusingdirective}{}
868 entry, with an import attribute referring to the namespace
869 entry of the appropriate extension of the namespace (which
870 might be the original namespace entry) and no owned entries.
873 \textit{A \addtoindex{Fortran} use statement
874 \addtoindexx{Fortran!use statement}
875 with a \doublequote{rename list} may be
876 represented by an imported module entry with an import
877 attribute referring to the module and owned entries
878 corresponding to those entities that are renamed as part of
882 \textit{A \addtoindex{Fortran} use statement
883 \addtoindexx{Fortran!use statement}
884 with neither a \doublequote{rename list} nor
885 an \doublequote{only list} may be represented by an imported module
886 entry with an import attribute referring to the module and
887 no owned child entries.
890 \textit{A use statement with an \doublequote{only list} is represented by a
891 series of individual imported declaration entries as described
892 in Section \refersec{chap:importedorrenameddeclarationentries}.
895 \textit{A \addtoindex{Fortran} use statement for an entity in a module that is
896 \addtoindexx{Fortran!use statement}
897 itself imported by a use statement without an explicit mention
898 may be represented by an imported declaration entry that refers
899 to the original debugging information entry. For example, given
916 \textit{the imported declaration entry for Q within module C refers
917 directly to the variable declaration entry for X in module A
918 because there is no explicit representation for X in module B.
921 \textit{A similar situation arises for a \addtoindex{C++} using declaration
922 \addtoindexx{namespace (C++)!using declaration}
923 \addtoindexx{using declaration|see {namespace (C++), using declaration}}
924 that imports an entity in terms of a namespace alias. See
925 Appendix \refersec{app:namespaceexample}
929 \section{Subroutine and Entry Point Entries}
930 \label{chap:subroutineandentrypointentries}
932 The following tags exist to describe
933 debugging information entries
934 \addtoindexx{function entry|see{subroutine entry}}
936 \addtoindexx{subroutine entry}
938 \addtoindexx{subprogram entry}
940 % FIXME: is entry point entry the right index 'entry'?
941 \addtoindexx{entry point entry}
944 \begin{tabular}{lp{9.0cm}}
945 \DWTAGsubprogramTARG{} & A subroutine or function \\
946 \DWTAGinlinedsubroutine{} & A particular inlined
947 \addtoindexx{inlined subprogram entry}
948 instance of a subroutine or function \\
949 \DWTAGentrypointTARG{} & An alternate entry point \\
954 \subsection{General Subroutine and Entry Point Information}
955 \label{chap:generalsubroutineandentrypointinformation}
956 The subroutine or entry point entry has a \DWATname{}
957 attribute whose value is a null-terminated string containing the
958 subroutine or entry point name as it appears in the source program.
959 It may also have a \DWATlinkagename{} attribute as
960 described in Section \refersec{chap:linkagenames}.
962 If the name of the subroutine described by an entry with the
963 \addtoindexx{subprogram entry}
964 tag \DWTAGsubprogram{}
965 is visible outside of its containing
966 \hypertarget{chap:DWATexternalexternalsubroutine}{}
967 compilation unit, that entry has
968 \addtoindexx{external attribute}
970 \DWATexternal{} attribute,
971 which is a \livelink{chap:classflag}{flag}.
973 \textit{Additional attributes for functions that are members of a
974 class or structure are described in
975 Section \refersec{chap:memberfunctionentries}.
979 \hypertarget{chap:DWATmainsubprogrammainorstartingsubprogram}{}
982 \DWATmainsubprogram{}
984 \addtoindexx{main subprogram attribute}
986 a \livelink{chap:classflag}{flag} whose presence indicates that the
987 subroutine has been identified as the starting function of
988 the program. If more than one subprogram contains this
990 any one of them may be the starting subroutine of the program.
992 \textit{\addtoindex{Fortran} has a \addtoindex{PROGRAM statement}
993 which is used to specify
994 and provide a user\dash supplied name for the main subroutine of
998 \textit{A common debugger feature is to allow the debugger user to call
999 a subroutine within the subject program. In certain cases,
1000 however, the generated code for a subroutine will not obey
1001 the standard calling conventions for the target architecture
1002 and will therefore not be safe to call from within a debugger.
1005 A subroutine entry may
1006 \hypertarget{chap:DWATcallingconventionsubprogramcallingconvention}{}
1008 \DWATcallingconvention{}
1009 attribute, whose value is an
1010 \livelink{chap:classconstant}{integer constant}. The set of
1011 calling convention codes is given in
1012 Table \refersec{tab:callingconventioncodes}.
1014 \begin{simplenametable}[1.4in]{Calling convention codes}{tab:callingconventioncodes}
1018 \end{simplenametable}
1020 If this attribute is not present, or its value is the constant
1021 \DWCCnormalTARG, then the subroutine may be safely called by
1022 obeying the \doublequote{standard} calling conventions of the target
1023 architecture. If the value of the calling convention attribute
1024 is the constant \DWCCnocallTARG, the subroutine does not obey
1025 standard calling conventions, and it may not be safe for the
1026 debugger to call this subroutine.
1028 If the semantics of the language of the compilation unit
1029 containing the subroutine entry distinguishes between ordinary
1030 subroutines and subroutines that can serve as the \doublequote{main
1031 program,} that is, subroutines that cannot be called
1032 directly according to the ordinary calling conventions,
1033 then the debugging information entry for such a subroutine
1034 may have a calling convention attribute whose value is the
1035 constant \DWCCprogramTARG.
1037 \textit{The \DWCCprogram{}
1038 value is intended to support \addtoindex{Fortran} main
1039 \addtoindexx{Fortran!main program}
1040 programs which in some implementations may not be callable
1041 or which must be invoked in a special way. It is not intended
1042 as a way of finding the entry address for the program.
1045 \textit{In \addtoindex{C}
1046 there is a difference between the types of functions
1047 declared using function prototype style declarations and
1048 those declared using non\dash prototype declarations.
1051 A subroutine entry declared with a function prototype style
1052 declaration may have
1053 \addtoindexx{prototyped attribute}
1055 \DWATprototyped{} attribute, which is
1056 a \livelink{chap:classflag}{flag}.
1058 \textit{The \addtoindex{Fortran}
1059 language allows the keywords \texttt{elemental}, \texttt{pure}
1060 and \texttt{recursive} to be included as part of the declaration of
1061 a subroutine; these attributes reflect that usage. These
1062 attributes are not relevant for languages that do not support
1063 similar keywords or syntax. In particular, the \DWATrecursive{}
1064 attribute is neither needed nor appropriate in languages such
1066 where functions support recursion by default.
1070 \hypertarget{chap:DWATelementalelementalpropertyofasubroutine}{}
1072 \addtoindexx{elemental attribute}
1074 \DWATelemental{} attribute, which
1075 is a \livelink{chap:classflag}{flag}.
1076 The attribute indicates whether the subroutine
1077 or entry point was declared with the \doublequote{elemental} keyword
1081 \hypertarget{chap:DWATpurepurepropertyofasubroutine}{}
1082 subprogram entry may have
1083 \addtoindexx{pure attribute}
1085 \DWATpure{} attribute, which is
1086 a \livelink{chap:classflag}{flag}.
1087 The attribute indicates whether the subroutine was
1088 declared with the \doublequote{pure} keyword or property.
1091 \hypertarget{chap:DWATrecursiverecursivepropertyofasubroutine}{}
1092 subprogram entry may have a
1093 \DWATrecursive{} attribute, which
1094 is a \livelink{chap:classflag}{flag}.
1095 The attribute indicates whether the subroutine
1096 or entry point was declared with the \doublequote{recursive} keyword
1101 \subsection{Subroutine and Entry Point Return Types}
1102 \label{chap:subroutineandentrypointreturntypes}
1105 \hypertarget{chap:DWATtypetypeofsubroutinereturn}{}
1106 the subroutine or entry point
1107 \addtoindexx{return type of subroutine}
1108 is a function that returns a
1109 value, then its debugging information entry has
1110 \addtoindexx{type attribute}
1111 a \DWATtype{} attribute
1112 to denote the type returned by that function.
1114 \textit{Debugging information entries for
1115 \addtoindex{C} void functions should
1116 not have an attribute for the return type. }
1118 \textit{Debugging information entries for declarations of \addtoindex{C++}
1119 member functions with an
1120 \addtoindex{\texttt{auto} return type} specifier should use an unspecified
1122 Section \refersec{chap:unspecifiedtypeentries}).
1123 The debugging information entry for the corresponding definition
1124 should provide the deduced return type. This practice causes the description of
1125 the containing class to be consistent across compilation units, allowing the class
1126 declaration to be placed into a separate type unit if desired.}
1129 \subsection{Subroutine and Entry Point Locations}
1130 \label{chap:subroutineandentrypointlocations}
1132 A subroutine entry may have either a \DWATlowpc{} and
1133 \DWAThighpc{} pair of attributes or a \DWATranges{} attribute
1134 \addtoindexx{ranges attribute}
1136 \addtoindexx{high PC attribute}
1138 \addtoindexx{low PC attribute}
1139 encode the contiguous or non\dash contiguous address
1140 ranges, respectively, of the machine instructions generated
1141 for the subroutine (see
1142 Section \refersec{chap:codeaddressesandranges}).
1145 \hypertarget{chap:DWATentrypcentryaddressofsubprogram}{}
1146 subroutine entry may also have
1147 \addtoindexx{entry pc attribute!for subroutine}
1149 \DWATentrypc{} attribute
1150 whose value is the address of the first executable instruction
1151 of the subroutine (see
1152 Section \refersec{chap:entryaddress}).
1154 An entry point has a \DWATlowpc{} attribute whose value is the
1155 relocated address of the first machine instruction generated
1156 for the entry point.
1159 \DWATentrypc{} attribute
1160 \addtoindexx{entry pc attribute!for subroutine}
1162 also seem appropriate
1163 for this purpose, historically the
1164 \DWATlowpc{} attribute
1166 \DWATentrypc{} was introduced (in
1167 \addtoindex{DWARF Version 3}).
1168 There is insufficient reason to change this.}
1174 \addtoindexx{address class!attribute}
1176 \hypertarget{chap:DWATaddressclasssubroutineorsubroutinetype}{}
1180 \DWATaddressclass{} attributes,
1181 as appropriate, to specify
1182 which segments the code for the subroutine resides in and
1183 the addressing mode to be used in calling that subroutine.
1185 A subroutine entry representing a subroutine declaration
1186 that is not also a definition does not have code address or
1190 \subsection{Declarations Owned by Subroutines and Entry Points}
1191 \label{chap:declarationsownedbysubroutinesandentrypoints}
1193 The declarations enclosed by a subroutine or entry point are
1194 represented by debugging information entries that are owned
1195 by the subroutine or entry point entry. Entries representing
1196 \addtoindexx{formal parameter}
1197 the formal parameters of the subroutine or entry point appear
1198 in the same order as the corresponding declarations in the
1202 \textit{There is no ordering requirement for entries for declarations
1203 that are children of subroutine or entry point entries but
1204 that do not represent formal parameters. The formal parameter
1205 entries may be interspersed with other entries used by formal
1206 parameter entries, such as type entries.}
1208 The unspecified parameters of a variable parameter list are
1209 represented by a debugging information entry\addtoindexx{unspecified parameters entry}
1211 \DWTAGunspecifiedparametersTARG.
1213 The entry for a subroutine that includes a
1214 \addtoindex{Fortran}
1215 \addtoindexx{Fortran!common block}
1216 \livelink{chap:fortrancommonblock}{common}
1217 \livelink{chap:commonblockentry}{block}
1218 \addtoindexx{common block|see{Fortran common block}}
1219 has a child entry with the
1220 tag \DWTAGcommoninclusionTARG.
1222 \hypertarget{chap:commonreferencecommonblockusage}{}
1223 common inclusion entry has a
1224 \DWATcommonreference{} attribute
1225 whose value is a \livelink{chap:classreference}{reference}
1226 to the debugging information entry
1227 for the common \nolink{block} being included
1228 (see Section \refersec{chap:commonblockentries}).
1230 \subsection{Low-Level Information}
1231 \label{chap:lowlevelinformation}
1234 \hypertarget{chap:DWATreturnaddrsubroutinereturnaddresssavelocation}{}
1235 subroutine or entry point entry may have
1236 \addtoindexx{return address attribute}
1239 attribute, whose value is a location description. The location
1240 calculated is the place where the return address for the
1241 subroutine or entry point is stored.
1244 \hypertarget{chap:DWATframebasesubroutineframebaseaddress}{}
1245 subroutine or entry point entry may also have
1246 \addtoindexx{frame base attribute}
1248 \DWATframebase{} attribute, whose value is a location
1249 description that computes the \doublequote{frame base} for the
1250 subroutine or entry point. If the location description is
1251 a simple register location description, the given register
1252 contains the frame base address. If the location description is
1253 a DWARF expression, the result of evaluating that expression
1254 is the frame base address. Finally, for a
1255 \addtoindex{location list},
1256 this interpretation applies to each location description
1257 contained in the list of \addtoindex{location list} entries.
1259 \textit{The use of one of the \DWOPregn{}
1261 context is equivalent to using
1264 compact. However, these are not equivalent in general.}
1267 \textit{The frame base for a procedure is typically an address fixed
1268 relative to the first unit of storage allocated for the
1269 procedure\textquoteright s stack frame. The \DWATframebase{} attribute
1270 can be used in several ways:}
1271 \begin{enumerate}[1. ]
1272 \item \textit{In procedures that need
1273 \addtoindexx{location list}
1274 location lists to locate local
1275 variables, the \DWATframebase{} can hold the needed location
1276 list, while all variables\textquoteright\ location descriptions can be
1277 simpler ones involving the frame base.}
1279 \item \textit{It can be used in resolving \doublequote{up\dash level} addressing
1280 within nested routines.
1281 (See also \DWATstaticlink, below)}
1285 \textit{Some languages support nested subroutines. In such languages,
1286 it is possible to reference the local variables of an
1287 outer subroutine from within an inner subroutine. The
1288 \DWATstaticlink{} and \DWATframebase{} attributes allow
1289 debuggers to support this same kind of referencing.}
1292 \hypertarget{chap:DWATstaticlinklocationofuplevelframe}{}
1294 \addtoindexx{address!uplevel|see {static link attribute}}
1295 \addtoindexx{uplevel address|see {static link attribute}}
1296 subroutine or entry point is nested, it may have a
1298 attribute, whose value is a location
1299 description that computes the frame base of the relevant
1300 instance of the subroutine that immediately encloses the
1301 subroutine or entry point.
1303 In the context of supporting nested subroutines, the
1304 \DWATframebase{} attribute value should obey the following
1307 \begin{enumerate}[1. ]
1308 \item It should compute a value that does not change during the
1309 life of the procedure, and
1311 \item The computed value should be unique among instances of
1312 the same subroutine. (For typical \DWATframebase{} use, this
1313 means that a recursive subroutine\textquoteright s stack frame must have
1314 non\dash zero size.)
1317 \textit{If a debugger is attempting to resolve an up\dash level reference
1318 to a variable, it uses the nesting structure of DWARF to
1319 determine which subroutine is the lexical parent and the
1320 \DWATstaticlink{} value to identify the appropriate active
1321 frame of the parent. It can then attempt to find the reference
1322 within the context of the parent.}
1326 \subsection{Types Thrown by Exceptions}
1327 \label{chap:typesthrownbyexceptions}
1329 \textit{In \addtoindex{C++} a subroutine may declare a set of types which
1330 it may validly throw.}
1332 If a subroutine explicitly declares that it may throw
1333 \addtoindexx{exception thrown|see{thrown type entry}}
1335 \addtoindexx{thrown exception|see{thrown type entry}}
1336 exception of one or more types, each such type is
1337 represented by a debugging information entry with
1338 \addtoindexx{thrown type entry}
1340 \DWTAGthrowntypeTARG.
1341 Each such entry is a child of the entry
1342 representing the subroutine that may throw this type. Each
1343 thrown type entry contains
1344 \addtoindexx{type attribute}
1345 a \DWATtype{} attribute, whose
1346 value is a \livelink{chap:classreference}{reference}
1347 to an entry describing the type of the
1348 exception that may be thrown.
1350 \subsection{Function Template Instantiations}
1351 \label{chap:functiontemplateinstantiations}
1353 \textit{In \addtoindex{C++}, a function template is a generic definition of
1354 a function that is instantiated differently for calls with
1355 values of different types. DWARF does not represent the generic
1356 template definition, but does represent each instantiation.}
1359 A \addtoindex{template instantiation} is represented by a debugging
1360 information entry with the
1361 \addtoindexx{subprogram entry!use for template instantiation}
1362 tag \DWTAGsubprogram.
1364 exceptions, such an entry will contain the same attributes and
1365 will have the same types of child entries as would an entry
1366 for a subroutine defined explicitly using the instantiation
1367 types and values. The exceptions are:
1369 \begin{enumerate}[1. ]
1370 \item Template parameters are described and referenced as specified in
1371 Section \refersec{chap:templateparameters}.
1373 \item If the compiler has generated a special compilation unit
1374 to hold the template instantiation and that compilation unit
1375 has a different name from the compilation unit containing
1376 the template definition, the name attribute for the debugging
1377 information entry representing that compilation unit is empty
1380 \item If the subprogram entry representing the template
1381 instantiation or any of its child entries contain declaration
1382 coordinate attributes, those attributes refer to the source
1383 for the template definition, not to any source generated
1384 artificially by the compiler for this instantiation.
1389 \subsection{Inlinable and Inlined Subroutines}
1390 A declaration or a definition of an inlinable subroutine
1391 is represented by a debugging information entry with the
1395 \addtoindexx{subprogram entry!use in inlined subprogram}
1397 \hypertarget{chap:DWATinlineinlinedsubroutine}{}
1398 explicitly declared to be available for inline expansion or
1399 that was expanded inline implicitly by the compiler has
1400 \addtoindexx{inline attribute}
1402 \DWATinline{} attribute whose value is an
1403 \livelink{chap:classconstant}{integer constant}. The
1404 set of values for the \DWATinline{} attribute is given in
1405 Table \refersec{tab:inlinecodes}.
1409 \caption{Inline codes}
1410 \label{tab:inlinecodes}
1411 \begin{tabular}{l|p{8cm}}
1413 Name&Meaning\\ \hline
1414 \DWINLnotinlinedTARG{} & Not declared inline nor inlined by the
1415 \mbox{compiler} (equivalent to the absence of the
1416 containing \DWATinline{} attribute) \\
1417 \DWINLinlinedTARG{} & Not declared inline but inlined by the \mbox{compiler} \\
1418 \DWINLdeclarednotinlinedTARG{} & Declared inline but
1419 not inlined by the \mbox{compiler} \\
1420 \DWINLdeclaredinlinedTARG{} & Declared inline and inlined by the
1426 \textit{In \addtoindex{C++}, a function or a constructor declared with
1427 \addttindex{constexpr} is implicitly declared inline. The abstract inline
1428 instance (see below) is represented by a debugging information
1429 entry with the tag \DWTAGsubprogram. Such an entry has a
1430 \DWATinline{} attribute whose value is \DWINLinlined.}
1433 \subsubsection{Abstract Instances}
1434 \label{chap:abstractinstances}
1435 Any debugging information entry that is owned (either
1436 \hypertarget{chap:DWATinlineabstracttinstance}{}
1437 directly or indirectly) by a debugging information entry
1439 \DWATinline{} attribute is referred to
1440 \addtoindexx{abstract instance!entry}
1441 as an \doublequote{abstract instance entry.}
1442 Any subroutine entry
1444 \addtoindexx{inline attribute}
1445 a \DWATinline{} attribute whose value is other
1446 than \DWINLnotinlined{}
1448 \addtoindexx{abstract instance!root}
1449 an \doublequote{abstract instance root.}
1450 Any set of abstract instance entries that are all
1451 children (either directly or indirectly) of some abstract
1452 instance root, together with the root itself, is known as
1453 \addtoindexx{abstract instance!tree}
1454 an \doublequote{abstract instance tree.} However, in the case where
1455 an abstract instance tree is nested within another abstract
1456 instance tree, the entries in the
1457 \addtoindex{nested abstract instance}
1458 tree are not considered to be entries in the outer abstract
1461 Each abstract instance root is either part of a larger
1462 \addtoindexx{abstract instance!root}
1463 tree (which gives a context for the root) or
1464 \addtoindexx{specification attribute}
1466 \DWATspecification{}
1467 to refer to the declaration in context.
1469 \textit{For example, in \addtoindex{C++} the context might be a namespace
1470 declaration or a class declaration.}
1472 \textit{Abstract instance trees are defined so that no entry is part
1473 of more than one abstract instance tree. This simplifies the
1474 following descriptions.}
1476 A debugging information entry that is a member of an abstract
1477 instance tree should not contain any attributes which describe
1478 aspects of the subroutine which vary between distinct inlined
1479 expansions or distinct out\dash of\dash line expansions. For example,
1480 \addtoindexx{entry pc attribute!and abstract instance}
1491 \addtoindexx{location attribute!and abstract instance}
1493 \addtoindexx{ranges attribute!and abstract instance}
1495 \addtoindexx{high PC attribute!and abstract instance}
1497 \addtoindexx{low PC attribute!and abstract instance}
1499 \addtoindexx{segment attribute!and abstract instance}
1501 \addtoindexx{return address attribute!and abstract instance}
1503 \addtoindexx{segment attribute!and abstract instance}
1505 \addtoindexx{start scope attribute!and abstract instance}
1509 \textit{It would not make sense normally to put these attributes into
1510 abstract instance entries since such entries do not represent
1511 actual (concrete) instances and thus do not actually exist at
1512 run\dash time. However,
1513 see Appendix \refersec{app:inlineouteronenormalinner}
1514 for a contrary example.}
1516 The rules for the relative location of entries belonging to
1517 abstract instance trees are exactly the same as for other
1518 similar types of entries that are not abstract. Specifically,
1519 the rule that requires that an entry representing a declaration
1520 be a direct child of the entry representing the scope of the
1521 declaration applies equally to both abstract and non\dash abstract
1522 entries. Also, the ordering rules for formal parameter entries,
1523 member entries, and so on, all apply regardless of whether
1524 or not a given entry is abstract.
1527 \subsubsection{Concrete Inlined Instances}
1528 \label{chap:concreteinlinedinstances}
1530 Each inline expansion of a subroutine is represented
1531 by a debugging information entry with the
1532 tag \DWTAGinlinedsubroutineTARG.
1533 Each such entry should be a direct
1534 child of the entry that represents the scope within which
1535 the inlining occurs.
1537 Each inlined subroutine entry may have either a
1539 and \DWAThighpc{} pair
1541 \addtoindexx{high PC attribute}
1543 \addtoindexx{low PC attribute}
1545 \addtoindexx{ranges attribute}
1548 attribute whose values encode the contiguous or non\dash contiguous
1549 address ranges, respectively, of the machine instructions
1550 generated for the inlined subroutine (see
1551 Section \referfol{chap:codeaddressesandranges}).
1553 \hypertarget{chap:DWATentrypcentryaddressofinlinedsubprogram}{}
1554 inlined subroutine entry may
1555 \addtoindexx{inlined subprogram entry!in concrete instance}
1557 \addtoindexx{inlined subprogram entry}
1559 \addtoindexx{entry pc attribute!for inlined subprogram}
1562 attribute, representing the first executable instruction of
1563 the inline expansion (see
1564 Section \refersec{chap:entryaddress}).
1566 % Positions of the 3 targets here is a bit arbitrary.
1568 \hypertarget{chap:DWATcalllinelinenumberofinlinedsubroutinecall}{}
1570 \hypertarget{chap:DWATcallcolumncolumnpositionofinlinedsubroutinecall}{}
1572 \hypertarget{chap:DWATcallfilefilecontaininginlinedsubroutinecall}{}
1573 may also have \DWATcallfile,
1574 \DWATcallline{} and \DWATcallcolumn{} attributes,
1576 value is an \livelink{chap:classconstant}{integer constant}.
1577 These attributes represent the
1578 source file, source line number, and source column number,
1579 respectively, of the first character of the statement or
1580 expression that caused the inline expansion. The call file,
1581 call line, and call column attributes are interpreted in
1582 the same way as the declaration file, declaration line, and
1583 declaration column attributes, respectively (see
1584 Section \refersec{chap:declarationcoordinates}).
1586 \textit{The call file, call line and call column coordinates do not
1587 describe the coordinates of the subroutine declaration that
1588 was inlined, rather they describe the coordinates of the call.
1591 An inlined subroutine entry
1592 \hypertarget{chap:DWATconstexprcompiletimeconstantfunction}{}
1595 attribute, which is a \livelink{chap:classflag}{flag}
1596 whose presence indicates that the
1597 subroutine has been evaluated as a compile\dash time constant. Such
1598 an entry may also have a \DWATconstvalue{} attribute,
1599 whose value may be of any form that is appropriate for the
1600 representation of the subroutine's return value. The value of
1601 this attribute is the actual return value of the subroutine,
1602 represented as it would be on the target architecture.
1604 \textit{In \addtoindex{C++}, if a function or a constructor declared with
1605 \addttindex{constexpr}
1606 is called with constant expressions, then the corresponding
1607 concrete inlined instance has a
1608 \DWATconstexpr{} attribute,
1609 as well as a \DWATconstvalue{} attribute whose value represents
1610 the actual return value of the concrete inlined instance.}
1612 Any debugging information entry that is owned (either
1613 directly or indirectly) by a debugging information entry
1614 with the tag \DWTAGinlinedsubroutine{} is referred to as a
1615 \doublequote{concrete inlined instance entry.} Any entry that has
1617 \DWTAGinlinedsubroutine{}
1618 is known as a \doublequote{concrete inlined instance root.}
1619 Any set of concrete inlined instance
1620 entries that are all children (either directly or indirectly)
1621 of some concrete inlined instance root, together with the root
1622 itself, is known as a \doublequote{concrete inlined instance tree.}
1623 However, in the case where a concrete inlined instance tree
1624 is nested within another concrete instance tree, the entries
1625 in the \addtoindex{nested concrete inline instance} tree
1626 are not considered to
1627 be entries in the outer concrete instance tree.
1629 \textit{Concrete inlined instance trees are defined so that no entry
1630 is part of more than one concrete inlined instance tree. This
1631 simplifies later descriptions.}
1633 Each concrete inlined instance tree is uniquely associated
1634 with one (and only one) abstract instance tree.
1636 \textit{Note, however, that the reverse is not true. Any given abstract
1637 instance tree may be associated with several different concrete
1638 inlined instance trees, or may even be associated with zero
1639 concrete inlined instance trees.}
1641 Concrete inlined instance entries may omit attributes that
1642 are not specific to the concrete instance (but present in
1643 the abstract instance) and need include only attributes that
1644 are specific to the concrete instance (but omitted in the
1645 abstract instance). In place of these omitted attributes, each
1646 \hypertarget{chap:DWATabstractorigininlineinstance}{}
1647 concrete inlined instance entry
1648 \addtoindexx{abstract origin attribute}
1650 \DWATabstractorigin{}
1651 attribute that may be used to obtain the missing information
1652 (indirectly) from the associated abstract instance entry. The
1653 value of the abstract origin attribute is a reference to the
1654 associated abstract instance entry.
1656 If an entry within a concrete inlined instance tree contains
1657 attributes describing the
1658 \addtoindexx{declaration coordinates!in concrete instance}
1659 \livelink{chap:declarationcoordinates}{declaration coordinates}
1660 of that entry, then those attributes should refer to the file, line
1661 and column of the original declaration of the subroutine,
1662 not to the point at which it was inlined. As a consequence,
1663 they may usually be omitted from any entry that has an abstract
1667 For each pair of entries that are associated via a
1668 \addtoindexx{abstract origin attribute}
1669 \DWATabstractorigin{} attribute, both members of the pair
1670 have the same tag. So, for example, an entry with the tag
1671 \DWTAGvariable{} can only be associated with another entry
1672 that also has the tag \DWTAGvariable. The only exception
1673 to this rule is that the root of a concrete instance tree
1674 (which must always have the tag \DWTAGinlinedsubroutine)
1675 can only be associated with the root of its associated abstract
1676 instance tree (which must have the tag \DWTAGsubprogram).
1679 In general, the structure and content of any given concrete
1680 inlined instance tree will be closely analogous to the
1681 structure and content of its associated abstract instance
1682 tree. There are a few exceptions:
1684 \begin{enumerate}[1. ]
1685 \item An entry in the concrete instance tree may be omitted if
1687 \addtoindexx{abstract origin attribute}
1688 \DWATabstractorigin{} attribute and either
1689 has no children, or its children are omitted. Such entries
1690 would provide no useful information. In C\dash like languages,
1691 such entries frequently include types, including structure,
1692 union, class, and interface types; and members of types. If any
1693 entry within a concrete inlined instance tree needs to refer
1694 to an entity declared within the scope of the relevant inlined
1695 subroutine and for which no concrete instance entry exists,
1696 the reference should refer to the abstract instance entry.
1698 \item Entries in the concrete instance tree which are associated
1699 with entries in the abstract instance tree such that neither
1700 has a \DWATname{} attribute,
1701 \addtoindexx{name attribute}
1702 and neither is referenced by
1703 any other debugging information entry, may be omitted. This
1704 may happen for debugging information entries in the abstract
1705 instance trees that became unnecessary in the concrete instance
1706 tree because of additional information available there. For
1707 example, an anonymous variable might have been created and
1708 described in the abstract instance tree, but because of
1709 the actual parameters for a particular inlined expansion,
1710 it could be described as a constant value without the need
1711 for that separate debugging information entry.
1713 \item A concrete instance tree may contain entries which do
1714 not correspond to entries in the abstract instance tree
1715 to describe new entities that are specific to a particular
1716 inlined expansion. In that case, they will not have associated
1717 entries in the abstract instance tree, should not contain
1718 \addtoindexx{abstract origin attribute}
1719 \DWATabstractorigin{} attributes, and must contain all their
1720 own attributes directly. This allows an abstract instance tree
1721 to omit debugging information entries for anonymous entities
1722 that are unlikely to be needed in most inlined expansions. In
1723 any expansion which deviates from that expectation, the
1724 entries can be described in its concrete inlined instance tree.
1728 \subsubsection{Out-of-Line Instances of Inlined Subroutines}
1729 \label{chap:outoflineinstancesofinlinedsubroutines}
1730 Under some conditions, compilers may need to generate concrete
1731 executable instances of inlined subroutines other than at
1732 points where those subroutines are actually called. Such
1733 concrete instances of inlined subroutines are referred to as
1734 \doublequote{concrete out\dash of\dash line instances.}
1736 \textit{In \addtoindex{C++}, for example,
1737 taking the address of a function declared
1738 to be inline can necessitate the generation of a concrete
1739 out\dash of\dash line instance of the given function.}
1741 The DWARF representation of a concrete out\dash of\dash line instance
1742 of an inlined subroutine is essentially the same as for a
1743 concrete inlined instance of that subroutine (as described in
1744 the preceding section). The representation of such a concrete
1745 % It is critical that the hypertarget and livelink be
1746 % separated to avoid problems with latex.
1747 out\dash of\dash line
1748 \addtoindexx{abstract origin attribute}
1750 \hypertarget{chap:DWATabstractoriginoutoflineinstance}{}
1752 \DWATabstractorigin{}
1753 attributes in exactly the same way as they are used for
1754 a concrete inlined instance (that is, as references to
1755 corresponding entries within the associated abstract instance
1758 The differences between the DWARF representation of a
1759 concrete out\dash of\dash line instance of a given subroutine and the
1760 representation of a concrete inlined instance of that same
1761 subroutine are as follows:
1763 \begin{enumerate}[1. ]
1764 \item The root entry for a concrete out\dash of\dash line instance
1765 of a given inlined subroutine has the same tag as does its
1766 associated (abstract) inlined subroutine entry (that is, tag
1767 \DWTAGsubprogram{} rather than \DWTAGinlinedsubroutine).
1769 \item The root entry for a concrete out\dash of\dash line instance tree
1770 is normally owned by the same parent entry that also owns
1771 the root entry of the associated abstract instance. However,
1772 it is not required that the abstract and out\dash of\dash line instance
1773 trees be owned by the same parent entry.
1777 \subsubsection{Nested Inlined Subroutines}
1778 \label{nestedinlinedsubroutines}
1779 Some languages and compilers may permit the logical nesting of
1780 a subroutine within another subroutine, and may permit either
1781 the outer or the nested subroutine, or both, to be inlined.
1783 For a non\dash inlined subroutine nested within an inlined
1784 subroutine, the nested subroutine is described normally in
1785 both the abstract and concrete inlined instance trees for
1786 the outer subroutine. All rules pertaining to the abstract
1787 and concrete instance trees for the outer subroutine apply
1788 also to the abstract and concrete instance entries for the
1792 For an inlined subroutine nested within another inlined
1793 subroutine, the following rules apply to their abstract and
1794 \addtoindexx{abstract instance!nested}
1795 \addtoindexx{concrete instance!nested}
1796 concrete instance trees:
1798 \begin{enumerate}[1. ]
1799 \item The abstract instance tree for the nested subroutine is
1800 described within the abstract instance tree for the outer
1801 subroutine according to the rules in
1802 Section \refersec{chap:abstractinstances}, and
1803 without regard to the fact that it is within an outer abstract
1806 \item Any abstract instance tree for a nested subroutine is
1807 always omitted within the concrete instance tree for an
1810 \item A concrete instance tree for a nested subroutine is
1811 always omitted within the abstract instance tree for an
1814 \item The concrete instance tree for any inlined or
1815 \addtoindexx{out-of-line instance}
1817 \addtoindexx{out-of-line-instance|see{concrete out-of-line-instance}}
1818 expansion of the nested subroutine is described within a
1819 concrete instance tree for the outer subroutine according
1821 Sections \refersec{chap:concreteinlinedinstances} or
1822 \referfol{chap:outoflineinstancesofinlinedsubroutines}
1824 and without regard to the fact that it is within an outer
1825 concrete instance tree.
1828 See Appendix \refersec{app:inliningexamples}
1829 for discussion and examples.
1831 \subsection{Trampolines}
1832 \label{chap:trampolines}
1834 \textit{A trampoline is a compiler\dash generated subroutine that serves as
1835 \hypertarget{chap:DWATtrampolinetargetsubroutine}{}
1836 an intermediary in making a call to another subroutine. It may
1837 adjust parameters and/or the result (if any) as appropriate
1838 to the combined calling and called execution contexts.}
1840 A trampoline is represented by a debugging information entry
1841 \addtoindexx{trampoline (subprogram) entry}
1842 with the tag \DWTAGsubprogram{} or \DWTAGinlinedsubroutine{}
1844 \addtoindexx{trampoline attribute}
1845 a \DWATtrampoline{} attribute.
1847 attribute indicates the target subroutine of the trampoline,
1848 that is, the subroutine to which the trampoline passes
1849 control. (A trampoline entry may but need not also have a
1850 \DWATartificial{} attribute.)
1853 The value of the trampoline attribute may be represented
1854 using any of the following forms, which are listed in order
1858 \item If the value is of class reference, then the value
1859 specifies the debugging information entry of the target
1862 \item If the value is of class address, then the value is
1863 the relocated address of the target subprogram.
1865 \item If the value is of class string, then the value is the
1866 (possibly mangled) \addtoindexx{mangled names}
1867 name of the target subprogram.
1869 \item If the value is of class \livelink{chap:classflag}{flag}, then the value true
1870 indicates that the containing subroutine is a trampoline but
1871 that the target subroutine is not known.
1875 The target subprogram may itself be a trampoline. (A sequence
1876 of trampolines necessarily ends with a non\dash trampoline
1879 \textit{In \addtoindex{C++}, trampolines may be used
1880 to implement derived virtual
1881 member functions; such trampolines typically adjust the
1882 \addtoindexx{this parameter}
1883 implicit this pointer parameter in the course of passing
1885 Other languages and environments may use trampolines
1886 in a manner sometimes known as transfer functions or transfer
1889 \textit{Trampolines may sometimes pass control to the target
1890 subprogram using a branch or jump instruction instead of a
1891 call instruction, thereby leaving no trace of their existence
1892 in the subsequent execution context. }
1894 \textit{This attribute helps make it feasible for a debugger to arrange
1895 that stepping into a trampoline or setting a breakpoint in
1896 a trampoline will result in stepping into or setting the
1897 breakpoint in the target subroutine instead. This helps to
1898 hide the compiler generated subprogram from the user. }
1900 \textit{If the target subroutine is not known, a debugger may choose
1901 to repeatedly step until control arrives in a new subroutine
1902 which can be assumed to be the target subroutine. }
1906 \section{Lexical Block Entries}
1907 \label{chap:lexicalblockentries}
1910 lexical \livetargi{chap:lexicalblock}{block}{lexical block}
1912 \addtoindexx{lexical block}
1913 a bracketed sequence of source statements
1914 that may contain any number of declarations. In some languages
1915 (including \addtoindex{C} and \addtoindex{C++}),
1916 \nolink{blocks} can be nested within other
1917 \nolink{blocks} to any depth.}
1919 % We do not need to link to the preceding paragraph.
1920 A lexical \nolink{block} is represented by a debugging information
1922 tag \DWTAGlexicalblockTARG.
1924 The lexical \livetargi{chap:lexicalblockentry}{block}{lexical block entry}
1926 either a \DWATlowpc{} and
1927 \DWAThighpc{} pair of
1929 \addtoindexx{high PC attribute}
1931 \addtoindexx{low PC attribute}
1933 \DWATranges{} attribute
1934 \addtoindexx{ranges attribute}
1935 whose values encode the contiguous or non-contiguous address
1936 ranges, respectively, of the machine instructions generated
1937 for the lexical \nolink{block}
1938 (see Section \refersec{chap:codeaddressesandranges}).
1941 \hypertarget{chap:DWATentrypcoflexicalblock}{}
1942 lexical block entry may also have
1943 \addtoindexx{entry pc attribute!for lexical block}
1945 \DWATentrypc{} attribute
1946 whose value is the address of the first executable instruction
1947 of the lexical block (see
1948 Section \refersec{chap:entryaddress}).
1950 If a name has been given to the
1951 lexical \nolink{block}
1953 program, then the corresponding
1954 lexical \nolink{block} entry has a
1955 \DWATname{} attribute whose
1956 \addtoindexx{name attribute}
1957 value is a null\dash terminated string
1958 containing the name of the lexical \nolink{block}
1962 \textit{This is not the same as a \addtoindex{C} or
1963 \addtoindex{C++} label (see below).}
1965 The lexical \nolink{block} entry owns
1966 debugging information entries that
1967 describe the declarations within that lexical \nolink{block}.
1969 one such debugging information entry for each local declaration
1970 of an identifier or inner lexical \nolink{block}.
1972 \section{Label Entries}
1973 \label{chap:labelentries}
1974 \textit{A label is a way of identifying a source statement. A labeled
1975 statement is usually the target of one or more \doublequote{go to}
1980 A label is represented by a debugging information entry with
1981 \addtoindexx{label entry}
1983 tag \DWTAGlabelTARG.
1984 The entry for a label should be owned by
1985 the debugging information entry representing the scope within
1986 which the name of the label could be legally referenced within
1989 The label entry has a \DWATlowpc{} attribute whose value
1990 is the relocated address of the first machine instruction
1991 generated for the statement identified by the label in
1992 the source program. The label entry also has a
1993 \DWATname{} attribute
1994 \addtoindexx{name attribute}
1995 whose value is a null-terminated string containing
1996 the name of the label as it appears in the source program.
1999 \section{With Statement Entries}
2000 \label{chap:withstatemententries}
2002 \textit{Both \addtoindex{Pascal} and
2003 \addtoindexx{Modula-2}
2004 Modula\dash 2 support the concept of a \doublequote{with}
2005 statement. The with statement specifies a sequence of
2006 executable statements within which the fields of a record
2007 variable may be referenced, unqualified by the name of the
2010 A with statement is represented by a
2011 \addtoindexi{debugging information entry}{with statement entry}
2012 with the tag \DWTAGwithstmtTARG.
2014 A with statement entry may have either a
2016 \DWAThighpc{} pair of attributes
2017 \addtoindexx{high PC attribute}
2019 \addtoindexx{low PC attribute}
2020 a \DWATranges{} attribute
2021 \addtoindexx{ranges attribute}
2022 whose values encode the contiguous or non\dash contiguous address
2023 ranges, respectively, of the machine instructions generated
2024 for the with statement
2025 (see Section \refersec{chap:codeaddressesandranges}).
2028 \hypertarget{chap:DWATentrypcofwithstmt}{}
2029 with statement entry may also have
2030 \addtoindexx{entry pc attribute!for with statement}
2032 \DWATentrypc{} attribute
2033 whose value is the address of the first executable instruction
2034 of the with statement (see
2035 Section \refersec{chap:entryaddress}).
2038 The with statement entry has
2039 \addtoindexx{type attribute}
2040 a \DWATtype{} attribute, denoting
2041 the type of record whose fields may be referenced without full
2042 qualification within the body of the statement. It also has
2043 \addtoindexx{location attribute}
2044 a \DWATlocation{} attribute, describing how to find the base
2045 address of the record object referenced within the body of
2049 \section{Try and Catch Block Entries}
2050 \label{chap:tryandcatchblockentries}
2052 \textit{In \addtoindex{C++} a lexical \livelink{chap:lexicalblock}{block} may be
2053 designated as a \doublequote{catch \nolink{block}.}
2054 A catch \livetargi{chap:catchblock}{block}{catch block} is an
2055 exception handler that handles
2056 exceptions thrown by an immediately
2057 preceding \doublequote{try \livelink{chap:tryblock}{block}.}
2058 A catch \livelink{chap:catchblock}{block}
2059 designates the type of the exception that it
2062 A try \livetargi{chap:tryblock}{block}{try block} is represented
2063 by a debugging information entry
2064 \addtoindexx{try block entry}
2065 with the tag \DWTAGtryblockTARG.
2066 A catch \livelink{chap:catchblock}{block} is represented by
2067 a debugging information entry with
2068 \addtoindexx{catch block entry}
2069 the tag \DWTAGcatchblockTARG.
2071 % nolink as we have links just above and do not have a combo link for both
2072 Both try and catch \nolink{block} entries may have either a
2074 \DWAThighpc{} pair of attributes
2075 \addtoindexx{high PC attribute}
2077 \addtoindexx{low PC attribute}
2079 \DWATranges{} attribute
2080 \addtoindexx{ranges attribute}
2081 whose values encode the contiguous
2082 or non\dash contiguous address ranges, respectively, of the
2083 machine instructions generated for the \livelink{chap:lexicalblock}{block}
2085 \refersec{chap:codeaddressesandranges}).
2088 \hypertarget{chap:DWATentrypcoftryblock}{}
2089 \hypertarget{chap:DWATentrypcofcatchblock}{}
2090 try or catch block entry may also have
2091 \addtoindexx{entry pc attribute!for try block}
2092 \addtoindexx{entry pc attribute!for catch block}
2094 \DWATentrypc{} attribute
2095 whose value is the address of the first executable instruction
2096 of the try or catch block (see
2097 Section \refersec{chap:entryaddress}).
2099 Catch \livelink{chap:catchblock}{block} entries have at
2100 least one child entry, an
2101 entry representing the type of exception accepted by
2102 that catch \livelink{chap:catchblock}{block}.
2103 This child entry has one of
2104 \addtoindexx{formal parameter entry!in catch block}
2106 \addtoindexx{unspecified parameters entry!in catch block}
2108 \DWTAGformalparameter{} or
2109 \DWTAGunspecifiedparameters,
2110 and will have the same form as other parameter entries.
2112 The siblings immediately following
2113 a try \livelink{chap:tryblock}{block} entry are its
2114 corresponding catch \livelink{chap:catchblock}{block} entries.