RE: [PATCH] Support for DWARF5 location lists entries

["Achra, Nitika" <Nitika.Achra@amd.com>]

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[AMD Official Use Only - Internal Distribution Only]

Hi Simon,

I have modified the commit message. Please find the attachment.

Regards,
Nitika Achra

-----Original Message-----
From: Simon Marchi <simark@simark.ca> 
Sent: Thursday, January 16, 2020 7:45 PM
To: Achra, Nitika <Nitika.Achra@amd.com>; gdb-patches@sourceware.org
Cc: Ali Tamur <tamur@google.com>; George, Jini Susan <JiniSusan.George@amd.com>
Subject: Re: [PATCH] Support for DWARF5 location lists entries

[CAUTION: External Email]

On 2020-01-16 6:29 a.m., Achra, Nitika wrote:
> [AMD Official Use Only - Internal Distribution Only]
>
> Hi Simon,
>
> Please find the attachment.
>
>
> *Handle DW_LLE_base_addressx, DW_LLE_startx_length and DW_LLE_start_length.
>
> Tested by running the testsuite before and after the patch and there is no increase in the number of test cases that fails.
> Tested with both -gdwarf-4 and -gdwarf-5 flags. Also tested -gslit-dwarf along with -gdwarf-4 as well as -gdwarf5 flags.
>
>
> gdb/ChangeLog:
>         *dwarf2loc.c (decode_debug_loclists_addresses): Handle
>           DW_LLE_base_addressx, DW_LLE_startx_length, DW_LLE_start_length.
>
> This is an effort to support DWARF5 in gdb.

Hi Achra,

The commit message of the patch is empty.  The text that is above, which describes what your patch does, should be placed in your git commit, such that it will appear in the patch file when you use "git format-patch".

This is the text that people will see when they do "git log", so you can do "git log"
to see how it's usually formatted.

Thanks,

Simon

[-- Attachment #2: 0001-Support-for-DWARF5-location-lists-entries.patch --]
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From f11af3868b64db169a7c5ac5ddf931e868252195 Mon Sep 17 00:00:00 2001
From: nitachra <Nitika.Achra@amd.com>
Date: Thu, 16 Jan 2020 16:43:21 +0530
Subject: [PATCH] Support for DWARF5 location lists entries

This patch handles DW_LLE_base_addressx, DW_LLE_startx_length and DW_LLE_start_length.

Tested by running the testsuite before and after the patch and there is no
increase in the number of test cases that fails. Tested with both -gdwarf-4
and -gdwarf-5 flags. Also tested -gslit-dwarf along with -gdwarf-4 as well
as -gdwarf5 flags.

This is an effort to support DWARF5 in gdb.

gdb/ChangeLog:

   *dwarf2loc.c (decode_debug_loclists_addresses): Handle
    DW_LLE_base_addressx, DW_LLE_startx_length, DW_LLE_start_length.
---
 gdb/dwarf2loc.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c
index 1fe6829100..cf358fbe61 100644
--- a/gdb/dwarf2loc.c
+++ b/gdb/dwarf2loc.c
@@ -173,6 +173,41 @@ decode_debug_loclists_addresses (struct dwarf2_per_cu_data *per_cu,
 
   switch (*loc_ptr++)
     {
+    case DW_LLE_base_addressx:
+      *low = 0;
+      loc_ptr = gdb_read_uleb128 (loc_ptr, buf_end, &u64);
+      if (loc_ptr == NULL)
+	 return DEBUG_LOC_BUFFER_OVERFLOW;
+      *high = dwarf2_read_addr_index (per_cu, u64);
+      *new_ptr = loc_ptr;
+      return DEBUG_LOC_BASE_ADDRESS;
+    case DW_LLE_startx_length:
+      loc_ptr = gdb_read_uleb128 (loc_ptr, buf_end, &u64);
+      if (loc_ptr == NULL)
+	 return DEBUG_LOC_BUFFER_OVERFLOW;
+      *low = dwarf2_read_addr_index (per_cu, u64);
+      *high = *low;
+      loc_ptr = gdb_read_uleb128 (loc_ptr, buf_end, &u64);
+      if (loc_ptr == NULL)
+	 return DEBUG_LOC_BUFFER_OVERFLOW;
+      *high += u64;
+      *new_ptr = loc_ptr;
+      return DEBUG_LOC_START_LENGTH;
+    case DW_LLE_start_length:
+      if (buf_end - loc_ptr < addr_size)
+	 return DEBUG_LOC_BUFFER_OVERFLOW;
+      if (signed_addr_p)
+	 *low = extract_signed_integer (loc_ptr, addr_size, byte_order);
+      else
+	 *low = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
+      loc_ptr += addr_size;
+      *high = *low;
+      loc_ptr = gdb_read_uleb128 (loc_ptr, buf_end, &u64);
+      if (loc_ptr == NULL)
+	 return DEBUG_LOC_BUFFER_OVERFLOW;
+      *high += u64;
+      *new_ptr = loc_ptr;
+      return DEBUG_LOC_START_LENGTH;
     case DW_LLE_end_of_list:
       *new_ptr = loc_ptr;
       return DEBUG_LOC_END_OF_LIST;
@@ -197,6 +232,10 @@ decode_debug_loclists_addresses (struct dwarf2_per_cu_data *per_cu,
       *high = u64;
       *new_ptr = loc_ptr;
       return DEBUG_LOC_START_END;
+    /* Following cases are not supported yet. */
+    case DW_LLE_startx_endx:
+    case DW_LLE_start_end:
+    case DW_LLE_default_location:
     default:
       return DEBUG_LOC_INVALID_ENTRY;
     }
-- 
2.17.1