gdb/testsuite: add test for .debug_{rng,loc}lists section without offset array

It is possible for the tables in the .debug_{rng,loc}lists sections to
not have an array of offsets.  In that case, the offset_entry_count
field of the header is 0.  The forms DW_FORM_{rng,loc}listx (reference
by index) can't be used with that table.  Instead, the
DW_FORM_sec_offset form, which references a {rng,loc}list by direct
offset in the section, must be used.  From what I saw, this is what GCC
currently produces.

Add tests for this case.  I didn't see any bug related to this, I just
think that it would be nice to have coverage for this. A new
`-with-offset-array` option is added to the `table` procs, used when
generating {rng,loc}lists, to decide whether to generate the offset
array.

gdb/testsuite/ChangeLog:

	* lib/dwarf.exp (rnglists): Add -no-offset-array option to
	table proc.
	* gdb.dwarf2/rnglists-sec-offset.exp: Add test for
	.debug_rnglists table without offset array.
	* gdb.dwarf2/loclists-sec-offset.exp: Add test for
	.debug_loclists table without offset array.

Change-Id: I8e34a7bf68c9682215ffbbf66600da5b7db91ef7

1 files changed, 38 insertions, 10 deletions

diff --git a/gdb/testsuite/lib/dwarf.exp b/gdb/testsuite/lib/dwarf.exp
index b444ef3..10fd88f 100644
--- a/gdb/testsuite/lib/dwarf.exp
+++ b/gdb/testsuite/lib/dwarf.exp
@@ -1392,6 +1392,10 @@ namespace eval Dwarf {
 	# The -post-header-label option can be used to define a label just after
 	# the header of the table.  This is the label that a DW_AT_rnglists_base
 	# attribute will usually refer to.
+	#
+	# The `-with-offset-array true|false` option can be used to control
+	# whether the headers of the location list tables have an array of
+	# offset.  The default is true.
 
 	proc table { args } {
 	    variable _debug_rnglists_table_count
@@ -1399,7 +1403,10 @@ namespace eval Dwarf {
 	    variable _debug_rnglists_offset_size
 	    variable _debug_rnglists_is_64_dwarf
 
-	    parse_args {{post-header-label ""}}
+	    parse_args {
+		{post-header-label ""}
+		{with-offset-array true}
+	    }
 
 	    if { [llength $args] != 1 } {
 		error "table proc expects one positional argument (body)"
@@ -1477,7 +1484,12 @@ namespace eval Dwarf {
 	    _op .2byte 5 "dwarf version"
 	    _op .byte $_debug_rnglists_addr_size "address size"
 	    _op .byte 0 "segment selector size"
-	    _op .4byte "$_debug_rnglists_list_count" "offset entry count"
+
+	    if { ${with-offset-array} } {
+	      _op .4byte "$_debug_rnglists_list_count" "offset entry count"
+	    } else {
+	      _op .4byte 0 "offset entry count"
+	    }
 
 	    define_label $post_header_label
 
@@ -1487,9 +1499,11 @@ namespace eval Dwarf {
 	    }
 
 	    # Emit the offset array.
-	    for {set list_idx 0} {$list_idx < $_debug_rnglists_list_count} {incr list_idx} {
-		set list_label [_compute_list_label $list_idx]
-		_op .${_debug_rnglists_offset_size}byte "$list_label - $post_header_label" "offset of list $list_idx"
+	    if { ${with-offset-array} } {
+		for {set list_idx 0} {$list_idx < $_debug_rnglists_list_count} {incr list_idx} {
+		    set list_label [_compute_list_label $list_idx]
+		    _op .${_debug_rnglists_offset_size}byte "$list_label - $post_header_label" "offset of list $list_idx"
+		}
 	    }
 
 	    # Emit the actual list data.
@@ -1565,6 +1579,10 @@ namespace eval Dwarf {
 	# The -post-header-label option can be used to define a label just after the
 	# header of the table.  This is the label that a DW_AT_loclists_base
 	# attribute will usually refer to.
+	#
+	# The `-with-offset-array true|false` option can be used to control
+	# whether the headers of the location list tables have an array of
+	# offset.  The default is true.
 
 	proc table { args } {
 	    variable _debug_loclists_table_count
@@ -1572,7 +1590,10 @@ namespace eval Dwarf {
 	    variable _debug_loclists_offset_size
 	    variable _debug_loclists_is_64_dwarf
 
-	    parse_args {{post-header-label ""}}
+	    parse_args {
+		{post-header-label ""}
+		{with-offset-array true}
+	    }
 
 	    if { [llength $args] != 1 } {
 		error "table proc expects one positional argument (body)"
@@ -1672,7 +1693,12 @@ namespace eval Dwarf {
 	    _op .2byte 5 "DWARF version"
 	    _op .byte $_debug_loclists_addr_size "address size"
 	    _op .byte 0 "segment selector size"
-	    _op .4byte $_debug_loclists_list_count "offset entry count"
+
+	    if { ${with-offset-array} } {
+	      _op .4byte "$_debug_loclists_list_count" "offset entry count"
+	    } else {
+	      _op .4byte 0 "offset entry count"
+	    }
 
 	    define_label $post_header_label
 
@@ -1682,9 +1708,11 @@ namespace eval Dwarf {
 	    }
 
 	    # Emit the offset array.
-	    for {set list_idx 0} {$list_idx < $_debug_loclists_list_count} {incr list_idx} {
-		set list_label [_compute_list_label $list_idx]
-		_op .${_debug_loclists_offset_size}byte "$list_label - $post_header_label" "offset of list $list_idx"
+	    if { ${with-offset-array} } {
+		for {set list_idx 0} {$list_idx < $_debug_loclists_list_count} {incr list_idx} {
+		    set list_label [_compute_list_label $list_idx]
+		    _op .${_debug_loclists_offset_size}byte "$list_label - $post_header_label" "offset of list $list_idx"
+		}
 	    }
 
 	    # Emit the actual list data.