1e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\documentclass{article} 2e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\usepackage[fancyhdr,pdf]{latex2man} 3e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm 4e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\input{common.tex} 5e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm 6e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\begin{document} 7e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm 8e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\begin{Name}{3}{libunwind-dynamic}{David Mosberger-Tang}{Programming Library}{Introduction to dynamic unwind-info}libunwind-dynamic -- libunwind-support for runtime-generated code 9e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\end{Name} 10e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm 11e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\section{Introduction} 12e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm 133d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmFor \Prog{libunwind} to do its job, it needs to be able to reconstruct 143d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmthe \emph{frame state} of each frame in a call-chain. The frame state 153d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmdescribes the subset of the machine-state that consists of the 163d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\emph{frame registers} (typically the instruction-pointer and the 173d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmstack-pointer) and all callee-saved registers (preserved registers). 183d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmThe frame state describes each register either by providing its 193d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmcurrent value (for frame registers) or by providing the location at 203d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmwhich the current value is stored (callee-saved registers). 213d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 223d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmFor statically generated code, the compiler normally takes care of 233d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmemitting \emph{unwind-info} which provides the minimum amount of 243d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidminformation needed to reconstruct the frame-state for each instruction 253d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmin a procedure. For dynamically generated code, the runtime code 263d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmgenerator must use the dynamic unwind-info interface provided by 273d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\Prog{libunwind} to supply the equivalent information. This manual 283d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmpage describes the format of this information in detail. 293d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 303d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmFor the purpose of this discussion, a \emph{procedure} is defined to 313d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmbe an arbitrary piece of \emph{contiguous} code. Normally, each 323d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmprocedure directly corresponds to a function in the source-language 333d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmbut this is not strictly required. For example, a runtime 343d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmcode-generator could translate a given function into two separate 353d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm(discontiguous) procedures: one for frequently-executed (hot) code and 363d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmone for rarely-executed (cold) code. Similarly, simple 373d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmsource-language functions (usually leaf functions) may get translated 383d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidminto code for which the default unwind-conventions apply and for such 393d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmcode, it is not strictly necessary to register dynamic unwind-info. 403d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 413d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmA procedure logically consists of a sequence of \emph{regions}. 423d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmRegions are nested in the sense that the frame state at the end of one 433d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmregion is, by default, assumed to be the frame state for the next 443d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmregion. Each region is thought of as being divided into a 453d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\emph{prologue}, a \emph{body}, and an \emph{epilogue}. Each of them 463d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmcan be empty. If non-empty, the prologue sets up the frame state for 473d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmthe body. For example, the prologue may need to allocate some space 483d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmon the stack and save certain callee-saved registers. The body 493d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmperforms the actual work of the procedure but does not change the 503d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmframe state in any way. If non-empty, the epilogue restores the 513d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmprevious frame state and as such it undoes or cancels the effect of 523d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmthe prologue. In fact, a single epilogue may undo the effect of the 533d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmprologues of several (nested) regions. 543d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 553d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmWe should point out that even though the prologue, body, and epilogue 563d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmare logically separate entities, optimizing code-generators will 573d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmgenerally interleave instructions from all three entities. For this 583d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmreason, the dynamic unwind-info interface of \Prog{libunwind} makes no 593d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmdistinction whatsoever between prologue and body. Similarly, the 603d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmexact set of instructions that make up an epilogue is also irrelevant. 613d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmThe only point in the epilogue that needs to be described explicitly 623d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmby the dynamic unwind-info is the point at which the stack-pointer 633d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmgets restored. The reason this point needs to be described is that 643d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmonce the stack-pointer is restored, all values saved in the 653d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmdeallocated portion of the stack frame become invalid and hence 663d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\Prog{libunwind} needs to know about it. The portion of the frame 673d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmstate not saved on the stack is assume to remain valid through the end 683d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmof the region. For this reason, there is usually no need to describe 693d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidminstructions which restore the contents of callee-saved registers. 70e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm 71e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidmWithin a region, each instruction that affects the frame state in some 72e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidmfashion needs to be described with an operation descriptor. For this 73e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidmpurpose, each instruction in the region is assigned a unique index. 74e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidmExactly how this index is derived depends on the architecture. For 75e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidmexample, on RISC and EPIC-style architecture, instructions have a 76e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidmfixed size so it's possible to simply number the instructions. In 77e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidmcontrast, most CISC use variable-length instruction encodings, so it 78e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidmis usually necessary to use a byte-offset as the index. Given the 79e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidminstruction index, the operation descriptor specifies the effect of 80e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidmthe instruction in an abstract manner. For example, it might express 81e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidmthat the instruction stores calle-saved register \Var{r1} at offset 16 82e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidmin the stack frame. 83e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm 84e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\section{Procedures} 85e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm 863d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmA runtime code-generator registers the dynamic unwind-info of a 873d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmprocedure by setting up a structure of type \Type{unw\_dyn\_info\_t} 883d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmand calling \Func{\_U\_dyn\_register}(), passing the address of the 893d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmstructure as the sole argument. The members of the 903d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\Type{unw\_dyn\_info\_t} structure are described below: 913d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\begin{itemize} 923d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{void~*}next] Private to \Prog{libunwind}. Must not be used 933d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm by the application. 943d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{void~*}prev] Private to \Prog{libunwind}. Must not be used 953d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm by the application. 963d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{unw\_word\_t} \Var{start\_ip}] The start-address of the 973d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm instructions of the procedure (remember: procedure are defined to be 983d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm contiguous pieces of code, so a single code-range is sufficient). 993d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{unw\_word\_t} \Var{end\_ip}] The end-address of the 1003d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm instructions of the procedure (non-inclusive, that is, 1013d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm \Var{end\_ip}-\Var{start\_ip} is the size of the procedure in 1023d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm bytes). 1033d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{unw\_word\_t} \Var{gp}] The global-pointer value in use 1043d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm for this procedure. The exact meaing of the global-pointer is 1053d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm architecture-specific and on some architecture, it is not used at 1063d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm all. 1073d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{int32\_t} \Var{format}] The format of the unwind-info. 1083d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm This member can be one of \Const{UNW\_INFO\_FORMAT\_DYNAMIC}, 1093d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm \Const{UNW\_INFO\_FORMAT\_TABLE}, or 1103d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm \Const{UNW\_INFO\_FORMAT\_REMOTE\_TABLE}. 1113d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{union} \Var{u}] This union contains one sub-member 1123d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm structure for every possible unwind-info format: 1133d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm \begin{description} 1143d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm \item[\Type{unw\_dyn\_proc\_info\_t} \Var{pi}] This member is used 1153d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm for format \Const{UNW\_INFO\_FORMAT\_DYNAMIC}. 1163d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm \item[\Type{unw\_dyn\_table\_info\_t} \Var{ti}] This member is used 1173d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm for format \Const{UNW\_INFO\_FORMAT\_TABLE}. 1183d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm \item[\Type{unw\_dyn\_remote\_table\_info\_t} \Var{rti}] This member 1193d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm is used for format \Const{UNW\_INFO\_FORMAT\_REMOTE\_TABLE}. 1203d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm \end{description}\ 1213d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm The format of these sub-members is described in detail below. 1223d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\end{itemize} 1233434090e32e1c7c566cf82eff1a14b530e364bdcmostang.com!davidm 1243d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\subsection{Proc-info format} 125e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm 1263d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmThis is the preferred dynamic unwind-info format and it is generally 1273d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmthe one used by full-blown runtime code-generators. In this format, 1283d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmthe details of a procedure are described by a structure of type 1293d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\Type{unw\_dyn\_proc\_info\_t}. This structure contains the following 1303d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmmembers: 1313d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\begin{description} 132e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm 1333d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{unw\_word\_t} \Var{name\_ptr}] The address of a 1343d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm (human-readable) name of the procedure or 0 if no such name is 1353d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm available. If non-zero, The string stored at this address must be 1363d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm ASCII NUL terminated. For source languages that use name-mangling 1373d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm (such as C++ or Java) the string stored at this address should be 1383d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm the \emph{demangled} version of the name. 139e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm 1403d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{unw\_word\_t} \Var{handler}] The address of the 1413d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm personality-routine for this procedure. Personality-routines are 1423d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm used in conjunction with exception handling. See the C++ ABI draft 1433d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm (http://www.codesourcery.com/cxx-abi/) for an overview and a 1443d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm description of the personality routine. If the procedure has no 1453d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm personality routine, \Var{handler} must be set to 0. 1463d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 1473d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{uint32\_t} \Var{flags}] A bitmask of flags. At the 1483d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm moment, no flags have been defined and this member must be 1493d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm set to 0. 1503d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 1513d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{unw\_dyn\_region\_info\_t~*}\Var{regions}] A NULL-terminated 1523d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm linked list of region-descriptors. See section ``Region 1533d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm descriptors'' below for more details. 1543d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 1553d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\end{description} 1563d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 1573d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\subsection{Table-info format} 1583d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 1593d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmThis format is generally used when the dynamically generated code was 1603d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmderived from static code and the unwind-info for the dynamic and the 1613d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmstatic versions is identical. For example, this format can be useful 1623d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmwhen loading statically-generated code into an address-space in a 1633d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmnon-standard fashion (i.e., through some means other than 1643d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\Func{dlopen}()). In this format, the details of a group of procedures 1653d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmis described by a structure of type \Type{unw\_dyn\_table\_info}. 1663d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmThis structure contains the following members: 1673d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\begin{description} 1683d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 1693d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{unw\_word\_t} \Var{name\_ptr}] The address of a 1703d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm (human-readable) name of the procedure or 0 if no such name is 1713d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm available. If non-zero, The string stored at this address must be 1723d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm ASCII NUL terminated. For source languages that use name-mangling 1733d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm (such as C++ or Java) the string stored at this address should be 1743d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm the \emph{demangled} version of the name. 1753d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 1763d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{unw\_word\_t} \Var{segbase}] The segment-base value 1773d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm that needs to be added to the segment-relative values stored in the 1783d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm unwind-info. The exact meaning of this value is 1793d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm architecture-specific. 1803d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 1813d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{unw\_word\_t} \Var{table\_len}] The length of the 1823d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm unwind-info (\Var{table\_data}) counted in units of words 1833d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm (\Type{unw\_word\_t}). 1843d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 1853d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{unw\_word\_t} \Var{table\_data}] A pointer to the actual 1863d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm data encoding the unwind-info. The exact format is 1873d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm architecture-specific (see architecture-specific sections below). 1883d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 1893d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\end{description} 1903d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 1913d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\subsection{Remote table-info format} 1923d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 1933d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmThe remote table-info format has the same basic purpose as the regular 1943d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmtable-info format. The only difference is that when \Prog{libunwind} 1953d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmuses the unwind-info, it will keep the table data in the target 1963d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmaddress-space (which may be remote). Consequently, the type of the 1973d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\Var{table\_data} member is \Type{unw\_word\_t} rather than a pointer. 1983d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmThis implies that \Prog{libunwind} will have to access the table-data 1993d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmvia the address-space's \Func{access\_mem}() call-back, rather than 2003d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmthrough a direct memory reference. 2013d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 2023d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmFrom the point of view of a runtime-code generator, the remote 2033d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmtable-info format offers no advantage and it is expected that such 2043d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmgenerators will describe their procedures either with the proc-info 2053d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmformat or the normal table-info format. The main reason that the 2063d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmremote table-info format exists is to enable the 2073d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmaddress-space-specific \Func{find\_proc\_info}() callback (see 2083d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\SeeAlso{unw\_create\_addr\_space}(3)) to return unwind tables whose 2093d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmdata remains in remote memory. This can speed up unwinding (e.g., for 2103d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidma debugger) because it reduces the amount of data that needs to be 2113d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmloaded from remote memory. 2123d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 2133d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\section{Regions descriptors} 2143d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 2153d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmA region descriptor is a variable length structure that describes how 2163d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmeach instruction in the region affects the frame state. Of course, 2173d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmmost instructions in a region usualy do not change the frame state and 2183d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmfor those, nothing needs to be recorded in the region descriptor. A 2193d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmregion descriptor is a structure of type 2203d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\Type{unw\_dyn\_region\_info\_t} and has the following members: 2213d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\begin{description} 2223d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{unw\_dyn\_region\_info\_t~*}\Var{next}] A pointer to the 2233d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm next region. If this is the last region, \Var{next} is \Const{NULL}. 2243d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{int32\_t} \Var{insn\_count}] The length of the region in 2253d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm instructions. Each instruction is assumed to have a fixed size (see 2263d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm architecture-specific sections for details). The value of 2273d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm \Var{insn\_count} may be negative in the last region of a procedure 2283d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm (i.e., it may be negative only if \Var{next} is \Const{NULL}). A 2293d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm negative value indicates that the region covers the last \emph{N} 2303d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm instructions of the procedure, where \emph{N} is the absolute value 2313d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm of \Var{insn\_count}. 2323d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{uint32\_t} \Var{op\_count}] The (allocated) length of 2333d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm the \Var{op\_count} array. 2343d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{unw\_dyn\_op\_t} \Var{op}] An array of dynamic unwind 2353d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm directives. See Section ``Dynamic unwind directives'' for a 2363d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm description of the directives. 2373d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\end{description} 2383d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmA region descriptor with an \Var{insn\_count} of zero is an 2393d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\emph{empty region} and such regions are perfectly legal. In fact, 2403d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmempty regions can be useful to establish a particular frame state 2413d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmbefore the start of another region. 2423d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 2433d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmA single region list can be shared across multiple procedures provided 2443d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmthose procedures share a common prologue and epilogue (their bodies 2453d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmmay differ, of course). Normally, such procedures consist of a canned 2463d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmprologue, the body, and a canned epilogue. This could be described by 2473d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmtwo regions: one covering the prologue and one covering the epilogue. 2483d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmSince the body length is variable, the latter region would need to 2493d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmspecify a negative value in \Var{insn\_count} such that 2503d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\Prog{libunwind} knows that the region covers the end of the procedure 2513d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm(up to the address specified by \Var{end\_ip}). 2523d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 2533d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmThe region descriptor is a variable length structure to make it 2543d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmpossible to allocate all the necessary memory with a single 2553d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmmemory-allocation request. To facilitate the allocation of a region 2563d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmdescriptors \Prog{libunwind} provides a helper routine with the 2573d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmfollowing synopsis: 258e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm 2593d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\noindent 2603d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\Type{size\_t} \Func{\_U\_dyn\_region\_size}(\Type{int} \Var{op\_count}); 2613d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 2623d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmThis routine returns the number of bytes needed to hold a region 2633d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmdescriptor with space for \Var{op\_count} unwind directives. Note 2643d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmthat the length of the \Var{op} array does not have to match exactly 2653d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmwith the number of directives in a region. Instead, it is sufficient 2663d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmif the \Var{op} array contains at least as many entries as there are 2673d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmdirectives, since the end of the directives can always be indicated 2683d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmwith the \Const{UNW\_DYN\_STOP} directive. 2693d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 2703d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\section{Dynamic unwind directives} 2713d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 2723d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmA dynamic unwind directive describes how the frame state changes 2733d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmat a particular point within a region. The description is in 2743d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmthe form of a structure of type \Type{unw\_dyn\_op\_t}. This 2753d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmstructure has the following members: 2763d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\begin{description} 2773d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{int8\_t} \Var{tag}] The operation tag. Must be one 2783d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm of the \Type{unw\_dyn\_operation\_t} values described below. 2793d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{int8\_t} \Var{qp}] The qualifying predicate that controls 2803d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm whether or not this directive is active. This is useful for 2813d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm predicated architecturs such as IA-64 or ARM, where the contents of 2823d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm another (callee-saved) register determines whether or not an 2833d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm instruction is executed (takes effect). If the directive is always 2843d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm active, this member should be set to the manifest constant 2853d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm \Const{\_U\_QP\_TRUE} (this constant is defined for all 2863d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm architectures, predicated or not). 2873d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{int16\_t} \Var{reg}] The number of the register affected 2883d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm by the instruction. 2893d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{int32\_t} \Var{when}] The region-relative number of 2903d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm the instruction to which this directive applies. For example, 2913d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm a value of 0 means that the effect described by this directive 2923d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm has taken place once the first instruction in the region has 2933d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm executed. 2943d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Type{unw\_word\_t} \Var{val}] The value to be applied by the 2953d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm operation tag. The exact meaning of this value varies by tag. See 2963d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm Section ``Operation tags'' below. 2973d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\end{description} 2983d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmIt is perfectly legitimate to specify multiple dynamic unwind 2993d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmdirectives with the same \Var{when} value, if a particular instruction 3003d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmhas a complex effect on the frame state. 3013d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 3023d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmEmpty regions by definition contain no actual instructions and as such 3033d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmthe directives are not tied to a particular instruction. By 3043d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmconvention, the \Var{when} member should be set to 0, however. 3053d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 3063d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmThere is no need for the dynamic unwind directives to appear 3073d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmin order of increasing \Var{when} values. If the directives happen to 3083d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmbe sorted in that order, it may result in slightly faster execution, 3093d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmbut a runtime code-generator should not go to extra lengths just to 3103d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmensure that the directives are sorted. 3113d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 3123d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmIMPLEMENTATION NOTE: should \Prog{libunwind} implementations for 3133d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmcertain architectures prefer the list of unwind directives to be 3143d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmsorted, it is recommended that such implementations first check 3153d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmwhether the list happens to be sorted already and, if not, sort the 3163d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmdirectives explicitly before the first use. With this approach, the 3173d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmoverhead of explicit sorting is only paid when there is a real benefit 3183d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmand if the runtime code-generator happens to generated sorted lists 3193d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmnaturally, the performance penalty is limited to a simple O(N) check. 3203d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 3213d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\subsection{Operations tags} 3223d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 3233d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmThe possible operation tags are defined by enumeration type 3243d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\Type{unw\_dyn\_operation\_t} which defines the following 3253d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmvalues: 3263d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\begin{description} 3273d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 3283d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Const{UNW\_DYN\_STOP}] Marks the end of the dynamic unwind 3293d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm directive list. All remaining entries in the \Var{op} array of the 3303d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm region-descriptor are ignored. This tag is guaranteed to have a 3313d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm value of 0. 3323d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 3333d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Const{UNW\_DYN\_SAVE\_REG}] Marks an instruction which saves 3343d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm register \Var{reg} to register \Var{val}. 335e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm 3363d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Const{UNW\_DYN\_SPILL\_FP\_REL}] Marks an instruction which 3373d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm spills register \Var{reg} to a frame-pointer-relative location. The 3383d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm frame-pointer-relative offset is given by the value stored in member 3393d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm \Var{val}. See the architecture-specific sections for a description 3403d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm of the stack frame layout. 3413d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 3423d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Const{UNW\_DYN\_SPILL\_SP\_REL}] Marks an instruction which 3433d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm spills register \Var{reg} to a stack-pointer-relative location. The 3443d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm stack-pointer-relative offset is given by the value stored in member 3453d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm \Var{val}. See the architecture-specific sections for a description 3463d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm of the stack frame layout. 3473d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 3483d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Const{UNW\_DYN\_ADD}] Marks an instruction which adds 3493d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm the constant value \Var{val} to register \Var{reg}. To add subtract 3503d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm a constant value, store the two's-complement of the value in 3513d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm \Var{val}. The set of registers that can be specified for this tag 3523d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm is described in the architecture-specific sections below. 3533d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 3543d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Const{UNW\_DYN\_POP\_FRAMES}] 3553d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 3563d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Const{UNW\_DYN\_LABEL\_STATE}] 3573d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 3583d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Const{UNW\_DYN\_COPY\_STATE}] 3593d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 3603d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\item[\Const{UNW\_DYN\_ALIAS}] 3613d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 3623d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\end{description} 3633d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 3643d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidmunw\_dyn\_op\_t 365e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm 366e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\_U\_dyn\_op\_save\_reg(); 367e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\_U\_dyn\_op\_spill\_fp\_rel(); 368e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\_U\_dyn\_op\_spill\_sp\_rel(); 369e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\_U\_dyn\_op\_add(); 370e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\_U\_dyn\_op\_pop\_frames(); 371e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\_U\_dyn\_op\_label\_state(); 372e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\_U\_dyn\_op\_copy\_state(); 373e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\_U\_dyn\_op\_alias(); 374e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\_U\_dyn\_op\_stop(); 375e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm 3763d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm\section{IA-64 specifics} 3773d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 3783d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm- meaning of segbase member in table-info/table-remote-info format 3793d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm- format of table\_data in table-info/table-remote-info format 3803d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm- instruction size: each bundle is counted as 3 instructions, regardless 3813d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm of template (MLX) 3823d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm- describe stack-frame layout, especially with regards to sp-relative 3833d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm and fp-relative addressing 3843d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm- UNW\_DYN\_ADD can only add to ``sp'' (always a negative value); use 3853d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm POP\_FRAMES otherwise 3863d24b59dbaa67b246d7b627a5f61e2b381d01838mostang.com!davidm 387e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\section{See Also} 388e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm 389e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\SeeAlso{libunwind(3)}, 390e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\SeeAlso{\_U\_dyn\_register(3)}, 391e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\SeeAlso{\_U\_dyn\_cancel(3)} 392e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm 393e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\section{Author} 394e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm 395e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\noindent 396e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidmDavid Mosberger-Tang\\ 39775f34ccb7dcdfd2b96e370824b3fd723b2f22b49David Mosberger-TangEmail: \Email{dmosberger@gmail.com}\\ 39875f34ccb7dcdfd2b96e370824b3fd723b2f22b49David Mosberger-TangWWW: \URL{http://www.nongnu.org/libunwind/}. 399e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\LatexManEnd 400e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm 401e91ef297272549a1fde65db731125d70d9376f64mostang.com!davidm\end{document} 402