freebsd-skq/contrib/elftoolchain/libdwarf/dwarf_add_expr_gen.3
emaste b54d7a9715 Update to ELF Tool Chain r3668
Highlights:
- Make sure that only TLS sections are sorted into TLS segment.
- Fixed multiple errors in "Section to Segment mapping".
- Man page updates
- ar improvements
- elfcopy: avoid filter_reloc uninitialized variable for rela
- elfcopy: avoid stripping relocations from static binaries
- readelf: avoid printing directory in front of absolute path
- readelf: add NT_FREEBSD_FEATURE_CTL FreeBSD note type
- test improvements

NOTES:

Some of these changes originated in FreeBSD and simply reduce diffs
between contrib and vendor.

ELF Tool Chain ar is not (currently) used in FreeBSD, and there are
improvements in both FreeBSD and ELF Tool Chain ar that are not in
the other.

Sponsored by:	The FreeBSD Foundation
2019-01-10 14:35:23 +00:00

119 lines
3.4 KiB
Groff

.\" Copyright (c) 2011 Kai Wang
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" $Id: dwarf_add_expr_gen.3 3640 2018-10-14 14:09:13Z jkoshy $
.\"
.Dd September 9, 2011
.Dt DWARF_ADD_EXPR_GEN 3
.Os
.Sh NAME
.Nm dwarf_add_expr_gen
.Nd add an operator to a location expression descriptor
.Sh LIBRARY
.Lb libdwarf
.Sh SYNOPSIS
.In libdwarf.h
.Ft "Dwarf_Unsigned"
.Fo dwarf_add_expr_gen
.Fa "Dwarf_P_Expr expr"
.Fa "Dwarf_Small opcode"
.Fa "Dwarf_Unsigned val1"
.Fa "Dwarf_Unsigned val2"
.Fa "Dwarf_Error *err"
.Fc
.Sh DESCRIPTION
Function
.Fn dwarf_add_expr_gen
adds a location expression operator to the location expression
descriptor referenced by argument
.Ar expr .
.Pp
Argument
.Ar expr
should reference a location expression descriptor allocated using
the function
.Xr dwarf_new_expr 3 .
.Pp
Argument
.Ar opcode
specifies the operation code of the location expression operator.
Valid values for this argument are those denoted by the
.Dv DW_OP_ Ns *
constants defined in
.In libdwarf.h .
.Pp
To generate a
.Dv DW_OP_addr
operation, application code should instead use
.Xr dwarf_add_expr_addr_b 3 .
.Pp
Argument
.Ar val1
specifies the first operand of the location expression operator.
.Pp
Argument
.Ar val2
specifies the second operand of the location expression operator.
.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_add_expr_gen
returns the size in bytes of the location expression byte stream
generated.
In case of an error, function
.Fn dwarf_add_expr_gen
returns
.Dv DW_DLV_NOCOUNT
and sets the argument
.Ar err .
.Sh ERRORS
Function
.Fn dwarf_add_expr_gen
can fail with:
.Bl -tag -width ".Bq Er DW_DLE_LOC_EXPR_BAD"
.It Bq Er DW_DLE_ARGUMENT
Argument
.Ar expr
was NULL.
.It Bq Er DW_DLE_LOC_EXPR_BAD
The operation code specified in argument
.Ar opcode
was invalid.
.It Bq Er DW_DLE_MEMORY
An out of memory condition was encountered during the execution of
the function.
.El
.Sh SEE ALSO
.Xr dwarf 3 ,
.Xr dwarf_add_AT_location_expr 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_new_expr 3