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Diffstat (limited to 'rtemstoolkit/elftoolchain/libdwarf/dwarf_loclist.3')
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diff --git a/rtemstoolkit/elftoolchain/libdwarf/dwarf_loclist.3 b/rtemstoolkit/elftoolchain/libdwarf/dwarf_loclist.3 new file mode 100644 index 0000000..2e95d74 --- /dev/null +++ b/rtemstoolkit/elftoolchain/libdwarf/dwarf_loclist.3 @@ -0,0 +1,230 @@ +.\" Copyright (c) 2011 Kai Wang +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" $Id: dwarf_loclist.3 2122 2011-11-09 15:35:14Z jkoshy $ +.\" +.Dd November 9, 2011 +.Os +.Dt DWARF_LOCLIST 3 +.Sh NAME +.Nm dwarf_loclist , +.Nm dwarf_loclist_n +.Nd retrieve DWARF location expression information +.Sh LIBRARY +.Lb libdwarf +.Sh SYNOPSIS +.In libdwarf.h +.Ft int +.Fo dwarf_loclist +.Fa "Dwarf_Attribute at" +.Fa "Dwarf_Locdesc **llbuf" +.Fa "Dwarf_Signed *listlen" +.Fa "Dwarf_Error *error" +.Fc +.Ft int +.Fo dwarf_loclist_n +.Fa "Dwarf_Attribute at" +.Fa "Dwarf_Locdesc ***llbuf" +.Fa "Dwarf_Signed *listlen" +.Fa "Dwarf_Error *error" +.Fc +.Sh DESCRIPTION +These functions retrieve the location expressions +associated with a DWARF attribute. +.Pp +Note: function +.Fn dwarf_loclist +is deprecated. +New application code should instead use function +.Fn dwarf_loclist_n +.Pp +Function +.Fn dwarf_loclist_n +retrieves the list of location expressions associated with a DWARF +attribute. +Argument +.Ar at +should reference a valid DWARF attribute. +Argument +.Ar llbuf +should point to a location which will hold a returned array of +pointers to +.Vt Dwarf_Locdesc +descriptors. +Argument +.Ar listlen +should point to a location which will be set to the number of +elements contained in the returned array. +If argument +.Ar err +is not NULL, it will be used to store error information in case +of an error. +.Pp +Function +.Fn dwarf_loclist +retrieves the first location expression associated with an attribute. +Argument +.Ar at +should reference a valid DWARF attribute. +Argument +.Ar llbuf +should point to a location which will hold the returned pointer +to a +.Vt Dwarf_Locdesc +descriptor. +Argument +.Ar listlen +should point to a location which will be always set to 1. +If argument +.Ar err +is not NULL, it will be used to store error information in case +of an error. +.Pp +.Vt Dwarf_Locdesc +descriptors are defined in the header file +.In libdwarf.h , +and consist of following fields: +.Pp +.Bl -tag -width ".Va ld_cents" -compact +.It Va ld_lopc +The lowest program counter address covered by the descriptor. +This field will be set to 0 if the descriptor is not associated with +an address range. +.It Va ld_hipc +The highest program counter address covered by the descriptor. +This field will be set to 0 if the descriptor is not associated with +an address range. +.It Va ld_cents +The number of entries returned in +.Va ld_s +field. +.It Va ld_s +Pointer to an array of +.Vt Dwarf_Loc +descriptors. +.El +.Pp +Each +.Vt Dwarf_Loc +descriptor represents one operation of a location expression. +These descriptors are defined in the header file +.In libdwarf.h , +and consist of following fields: +.Pp +.Bl -tag -width ".Va lr_number2" -compact +.It Va lr_atom +The operator name, one of the +.Dv DW_OP_* +constants defined in the header file +.In dwarf.h . +.It Va lr_number +The first operand of this operation. +.It Va lr_number2 +The second operand of this operation. +.It Va lr_offset +The byte offset of this operation within the containing location +expression. +.El +.Ss Memory Management +The memory area used for the descriptor array returned in argument +.Ar llbuf +is allocated by the +.Lb libdwarf . +When the descriptor array is no longer needed, application code should +use function +.Xr dwarf_dealloc 3 +to free the memory area in the following manner: +.Bl -enum +.It +First, the +.Ar ld_s +field of each +.Vt Dwarf_Locdesc +descriptor should be deallocated using the allocation type +.Dv DW_DLA_LOC_BLOCK . +.It +Then, the application should free each +.Vt Dwarf_Locdesc +descriptor using the allocation type +.Dv DW_DLA_LOCDESC . +.It +Finally, the +.Va llbuf +pointer should be deallocated using the allocation type +.Dv DW_DLA_LIST . +.El +.Sh RETURN VALUES +On success, these functions returns +.Dv DW_DLV_OK . +In case of an error, they return +.Dv DW_DLV_ERROR +and set the argument +.Ar err . +.Sh ERRORS +These functions can fail with: +.Bl -tag -width ".Bq Er DW_DLE_ARGUMENT" +.It Bq Er DW_DLE_ARGUMENT +One of the arguments +.Ar at , +.Ar llbuf +or +.Ar listlen +was NULL. +.It Bq Er DW_DLE_ARGUMENT +The attribute provided by argument +.Ar at +does not contain a location expression or is not associated with a +location expression list. +.El +.Sh EXAMPLE +To retrieve the location list associated with an attribute, use: +.Bd -literal -offset indent +Dwarf_Attribute at; +Dwarf_Locdesc **llbuf; +Dwarf_Signed lcnt; +Dwarf_Loc *lr; +Dwarf_Error de; +int i; + +if (dwarf_loclist_n(at, &llbuf, &lcnt, &de) != DW_DLV_OK) + errx(EXIT_FAILURE, "dwarf_loclist_n failed: %s", + dwarf_errmsg(de)); + +for (i = 0; i < lcnt; i++) { + /* ... Use llbuf[i] ... */ + for (j = 0; (Dwarf_Half) j < llbuf[i]->ld_cents; j++) { + lr = &llbuf[i]->ld_s[j]; + /* ... Use each Dwarf_Loc descriptor ... */ + } + dwarf_dealloc(dbg, llbuf[i]->ld_s, DW_DLA_LOC_BLOCK); + dwarf_dealloc(dbg, llbuf[i], DW_DLA_LOCDESC); +} +dwarf_dealloc(dbg, llbuf, DW_DLA_LIST); +.Ed +.Sh SEE ALSO +.Xr dwarf 3 , +.Xr dwarf_dealloc 3 , +.Xr dwarf_loclist_from_expr 3 , +.Xr dwarf_loclist_from_expr_a 3 , +.Xr dwarf_get_loclist_entry 3 |