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Diffstat (limited to 'rtemstoolkit/elftoolchain/libdwarf/dwarf_new_expr.3')
-rw-r--r-- | rtemstoolkit/elftoolchain/libdwarf/dwarf_new_expr.3 | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/rtemstoolkit/elftoolchain/libdwarf/dwarf_new_expr.3 b/rtemstoolkit/elftoolchain/libdwarf/dwarf_new_expr.3 new file mode 100644 index 0000000..d8f4c8a --- /dev/null +++ b/rtemstoolkit/elftoolchain/libdwarf/dwarf_new_expr.3 @@ -0,0 +1,135 @@ +.\" 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_new_expr.3 2074 2011-10-27 03:34:33Z jkoshy $ +.\" +.Dd September 8, 2011 +.Os +.Dt DWARF_NEW_EXPR 3 +.Sh NAME +.Nm dwarf_new_expr +.Nd create a location expression descriptor +.Sh LIBRARY +.Lb libdwarf +.Sh SYNOPSIS +.In libdwarf.h +.Ft "Dwarf_P_Expr" +.Fo dwarf_new_expr +.Fa "Dwarf_P_Debug dbg" +.Fa "Dwarf_Error *err" +.Fc +.Sh DESCRIPTION +Function +.Fn dwarf_new_expr +allocates a DWARF location expression descriptor used to build up a +location expression stream. +.Pp +The application can use the functions +.Xr dwarf_add_expr_gen 3 +and +.Xr dwarf_add_expr_addr_b 3 +to add location expression operators to the created descriptor. +When done, the application can call the function +.Xr dwarf_expr_into_block 3 +to retrieve the generated byte stream for the location expression, +or call the function +.Xr dwarf_add_AT_location_expr 3 +to create an attribute with the location expression stream as its +value. +.Pp +Argument +.Ar dbg +should reference a DWARF producer instance allocated using +.Xr dwarf_producer_init 3 +or +.Xr dwarf_producer_init_b 3 . +.Pp +If argument +.Ar err +is not NULL, it will be used to store error information in case +of an error. +.Sh RETURN VALUES +On success, function +.Fn dwarf_new_expr +returns the created location expression descriptor. +In case of an error, function +.Fn dwarf_new_expr +returns +.Dv DW_DLV_BADADDR +and sets the argument +.Ar err . +.Sh ERRORS +Function +.Fn dwarf_new_expr +can fail with: +.Bl -tag -width ".Bq Er DW_DLE_ARGUMENT" +.It Bq Er DW_DLE_ARGUMENT +Argument +.Ar dbg +was NULL. +.It Bq Er DW_DLE_MEMORY +An out of memory condition was encountered during the execution of +the function. +.El +.Sh EXAMPLES +To create a location expression descriptor, add location expression +operators to it and to retrieve the generated byte stream, +use: +.Bd -literal -offset indent +Dwarf_P_Debug dbg; +Dwarf_Error de; +Dwarf_P_Expr pe; +Dwarf_Addr buf; +Dwarf_Unsigned len; + +/* ...Assume that `dbg' refers to a DWARF producer instance... */ + +if ((pe = dwarf_new_expr(dbg, &de)) == DW_DLV_BADADDR) { + warnx("dwarf_new_expr failed: %s", dwarf_errmsg(-1)); + return; +} + +if (dwarf_add_expr_gen(pe, DW_OP_regx, 55, 0, &de) == + DW_DLV_NOCOUNT) { + warnx("dwarf_add_expr_gen failed: %s", dwarf_errmsg(-1)); + return; +} + +if ((buf = dwarf_expr_into_block(pe, &len, &de)) == + DW_DLV_BADADDR) { + warnx("dwarf_expr_into_block failed: %s", + dwarf_errmsg(-1)); + return; +} +.Ed +.Sh SEE ALSO +.Xr dwarf 3 , +.Xr dwarf_add_AT_location_expr 3 , +.Xr dwarf_add_expr_gen 3 , +.Xr dwarf_add_expr_addr 3 , +.Xr dwarf_add_expr_addr_b 3 , +.Xr dwarf_expr_current_offset 3 , +.Xr dwarf_expr_into_block 3 , +.Xr dwarf_producer_init 3 , +.Xr dwarf_producer_init_b 3 |