[PATCH] Fixed issues with processing of DW_FORM_loclistx / DW_FORM_rnglistx

["Sharma, Alok Kumar via Gdb-patches" <gdb-patches@sourceware.org>]

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Hi all,

I request you all to please review the patch. Below are the details.

Problem Description:
GDB produces internal error while processing DW_FORM_loclistx / DW_FORM_rnglistx,
$ make check RUNTESTFLAGS="CXX_FOR_TARGET=/path/to/clang++ " TEST=gdb.dwarf2/dw5-rnglist-test.exp
Below is the snippet from gdb.log file.
---------
(gdb) file /dir/gdb/testsuite/outputs/gdb.dwarf2/dw5-rnglist-test/dw5-rnglist-test
Reading symbols from /dir/gdb/testsuite/outputs/gdb.dwarf2/dw5-rnglist-test/dw5-rnglist-test...
gdb/dwarf2/attribute.h:232: internal-error: void attribute::set_unsigned_reprocess(ULONGEST): Assertion `form_requires_reprocessing ()' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) ERROR: Couldn't load dw5-rnglist-test into GDB (GDB internal error).
Resyncing due to internal error.
---------
This is due to incomplete handling of DW_FORM_loclistx / DW_FORM_rnglistx,
which is available with -gdwarf-5 option for clang compiler.
Resolution:
Forms DW_FORM_loclistx / DW_FORM_rnglistx need two phases of processing.
The required modifications in various routines are added to fix the issue.

gdb/ChangeLog:

2021-01-21  Alok Kumar Sharma  <AlokKumar.Sharma@amd.com>

        * dwarf2/attribute.c (form_is_unsigned): Handle DW_FORM_loclistx.
        (form_requires_reprocessing): Handle DW_FORM_loclistx and
        DW_FORM_rnglistx.
        * dwarf2/attribute.h (set_address): Handle DW_FORM_loclistx and
        DW_FORM_rnglistx.
        * dwarf2/read.c (read_attribute_reprocess): Replaced as_unsigned with
        as_unsigned_reprocess for DW_FORM_loclistx and DW_FORM_rnglistx.

Regards,
Alok

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From b42bf3de1e6bbc4f1598dd85a5545060a35aeb02 Mon Sep 17 00:00:00 2001
From: Alok Kumar Sharma <AlokKumar.Sharma@amd.com>
Date: Wed, 20 Jan 2021 10:56:16 +0530
Subject: [PATCH] [DWARF5] Fixed issues with processing of DW_FORM_loclistx /
 DW_FORM_rnglistx

GDB produces internal error while processing DW_FORM_loclistx / DW_FORM_rnglistx,
$ make check RUNTESTFLAGS="CXX_FOR_TARGET=/path/to/clang++ " TEST=gdb.dwarf2/dw5-rnglist-test.exp
Below is the snippet from gdb.log file.
---------
(gdb) file /dir/gdb/testsuite/outputs/gdb.dwarf2/dw5-rnglist-test/dw5-rnglist-test
Reading symbols from /dir/gdb/testsuite/outputs/gdb.dwarf2/dw5-rnglist-test/dw5-rnglist-test...
gdb/dwarf2/attribute.h:232: internal-error: void attribute::set_unsigned_reprocess(ULONGEST): Assertion `form_requires_reprocessing ()' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) ERROR: Couldn't load dw5-rnglist-test into GDB (GDB internal error).
Resyncing due to internal error.
---------
This is due to incomplete handling of DW_FORM_loclistx / DW_FORM_rnglistx,
which is available with -gdwarf-5 option for clang compiler.
Forms DW_FORM_loclistx / DW_FORM_rnglistx need two phases of processing.
The required modifications in various routines are added to fix the issue.

gdb/ChangeLog:

2021-01-21  Alok Kumar Sharma  <AlokKumar.Sharma@amd.com>

	* dwarf2/attribute.c (form_is_unsigned): Handle DW_FORM_loclistx.
	(form_requires_reprocessing): Handle DW_FORM_loclistx and
	DW_FORM_rnglistx.
	* dwarf2/attribute.h (set_address): Handle DW_FORM_loclistx and
	DW_FORM_rnglistx.
	* dwarf2/read.c (read_attribute_reprocess): Replaced as_unsigned with
	as_unsigned_reprocess for DW_FORM_loclistx and DW_FORM_rnglistx.

Change-Id: If8f54fc947dd686126563666b1463f8778618120
---
 gdb/ChangeLog          | 10 ++++++++++
 gdb/dwarf2/attribute.c |  5 ++++-
 gdb/dwarf2/attribute.h |  4 +++-
 gdb/dwarf2/read.c      |  7 +++++--
 4 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index d0e96331e5a..892248c831f 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,13 @@
+2021-01-21  Alok Kumar Sharma  <AlokKumar.Sharma@amd.com>
+
+	* dwarf2/attribute.c (form_is_unsigned): Handle DW_FORM_loclistx.
+	(form_requires_reprocessing): Handle DW_FORM_loclistx and
+	DW_FORM_rnglistx.
+	* dwarf2/attribute.h (set_address): Handle DW_FORM_loclistx and
+	DW_FORM_rnglistx.
+	* dwarf2/read.c (read_attribute_reprocess): Replaced as_unsigned with
+	as_unsigned_reprocess for DW_FORM_loclistx and DW_FORM_rnglistx.
+
 2021-01-20  Simon Marchi  <simon.marchi@polymtl.ca>
 
 	* gdb_bfd.c (debug_bfd_cache): Change type to bool.
diff --git a/gdb/dwarf2/attribute.c b/gdb/dwarf2/attribute.c
index 479261030c5..7caab5e3952 100644
--- a/gdb/dwarf2/attribute.c
+++ b/gdb/dwarf2/attribute.c
@@ -178,6 +178,7 @@ attribute::form_is_unsigned () const
 	  || form == DW_FORM_flag
 	  || form == DW_FORM_flag_present
 	  || form == DW_FORM_udata
+	  || form == DW_FORM_loclistx
 	  || form == DW_FORM_rnglistx
 	  || form == DW_FORM_ref1
 	  || form == DW_FORM_ref2
@@ -197,7 +198,9 @@ attribute::form_requires_reprocessing () const
 	  || form == DW_FORM_strx4
 	  || form == DW_FORM_GNU_str_index
 	  || form == DW_FORM_addrx
-	  || form == DW_FORM_GNU_addr_index);
+	  || form == DW_FORM_GNU_addr_index
+	  || form == DW_FORM_loclistx
+	  || form == DW_FORM_rnglistx);
 }
 
 /* See attribute.h.  */
diff --git a/gdb/dwarf2/attribute.h b/gdb/dwarf2/attribute.h
index a3ff9b0eb9c..b2cfa297369 100644
--- a/gdb/dwarf2/attribute.h
+++ b/gdb/dwarf2/attribute.h
@@ -239,7 +239,9 @@ struct attribute
   {
     gdb_assert (form == DW_FORM_addr
 		|| ((form == DW_FORM_addrx
-		     || form == DW_FORM_GNU_addr_index)
+		     || form == DW_FORM_GNU_addr_index
+		     || form == DW_FORM_loclistx
+		     || form == DW_FORM_rnglistx)
 		    && requires_reprocessing));
     u.addr = addr;
     requires_reprocessing = 0;
diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index 309ff8331e7..2e29d70a5cd 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -20289,10 +20289,13 @@ read_attribute_reprocess (const struct die_reader_specs *reader,
 					    attr->as_unsigned_reprocess ()));
 	break;
       case DW_FORM_loclistx:
-	attr->set_address (read_loclist_index (cu, attr->as_unsigned ()));
+	attr->set_address (read_loclist_index (cu,
+					       attr->as_unsigned_reprocess ()));
 	 break;
       case DW_FORM_rnglistx:
-	attr->set_address (read_rnglist_index (cu, attr->as_unsigned (), tag));
+	attr->set_address (read_rnglist_index (cu,
+					       attr->as_unsigned_reprocess (),
+					       tag));
 	break;
       case DW_FORM_strx:
       case DW_FORM_strx1:
-- 
2.17.1