libdw: Add new function dwarf_getlocations.

Using dwarf_getlocation it is possible to get single location
descriptions and with dwarf_getlocation_addr it is possible to
get a location list covering a specific address.  But sometimes
it is more convenient to get all ranges covered by a location
list.  For example when a specific address isn't covered and
you want to find alternative addresses where a location
description is defined.

dwarf_getlocations is modelled after dwarf_ranges. It enumerates
the location ranges and descriptions covered by the given
attribute.  In the first call OFFSET should be zero and *BASEP
need not be initialized.  Returns -1 for errors, zero when
there are no more locations to report, or a nonzero OFFSET
value to pass to the next call.  Each subsequent call must
preserve *BASEP from the prior call.  Successful calls fill in
*STARTP and *ENDP with a contiguous address range and *EXPR with
a pointer to an array of operations with length *EXPRLEN.  If
the attribute describes a single location description and not a
location list the first call (with OFFSET zero) will return the
location description in *EXPR with *STARTP set to zero and *ENDP
set to minus one.

ptrdiff_t dwarf_getlocations (Dwarf_Attribute *attr, ptrdiff_t offset,
                              Dwarf_Addr *basep, Dwarf_Addr *startp,
                              Dwarf_Addr *endp, Dwarf_Op **expr,
                              size_t *exprlen);

Signed-off-by: Mark Wielaard <mjw@redhat.com>

1 files changed, 17 insertions, 1 deletions

diff --git a/libdw/libdw.h b/libdw/libdw.h
index f5fc4e23..898aa74c 100644
--- a/libdw/libdw.h
+++ b/libdw/libdw.h
@@ -1,5 +1,5 @@
 /* Interfaces for libdw.
-   Copyright (C) 2002-2010 Red Hat, Inc.
+   Copyright (C) 2002-2010, 2013 Red Hat, Inc.
    This file is part of elfutils.
 
    This file is free software; you can redistribute it and/or modify
@@ -630,6 +630,22 @@ extern int dwarf_getlocation_addr (Dwarf_Attribute *attr, Dwarf_Addr address,
 				   Dwarf_Op **exprs, size_t *exprlens,
 				   size_t nlocs);
 
+/* Enumerate the locations ranges and descriptions covered by the
+   given attribute.  In the first call OFFSET should be zero and
+   *BASEP need not be initialized.  Returns -1 for errors, zero when
+   there are no more locations to report, or a nonzero OFFSET
+   value to pass to the next call.  Each subsequent call must preserve
+   *BASEP from the prior call.  Successful calls fill in *STARTP and
+   *ENDP with a contiguous address range and *EXPR with a pointer to
+   an array of operations with length *EXPRLEN.  If the attribute
+   describes a single location description and not a location list the
+   first call (with OFFSET zero) will return the location description
+   in *EXPR with *STARTP set to zero and *ENDP set to minus one.  */
+extern ptrdiff_t dwarf_getlocations (Dwarf_Attribute *attr,
+				     ptrdiff_t offset, Dwarf_Addr *basep,
+				     Dwarf_Addr *startp, Dwarf_Addr *endp,
+				     Dwarf_Op **expr, size_t *exprlen);
+
 /* Return the block associated with a DW_OP_implicit_value operation.
    The OP pointer must point into an expression that dwarf_getlocation
    or dwarf_getlocation_addr has returned given the same ATTR.  */