[gcc r12-2090] dwarf2ctf: the unit of sou field location is bits [PR101283]

[gcc r12-2090] dwarf2ctf: the unit of sou field location is bits [PR101283]

[Indu Bhagat]

https://gcc.gnu.org/g:151b423a82f4bf15e3225833028f5258ea254cb9

commit r12-2090-g151b423a82f4bf15e3225833028f5258ea254cb9
Author: Indu Bhagat <indu.bhagat@oracle.com>
Date:   Tue Jul 6 13:53:58 2021 -0700

    dwarf2ctf: the unit of sou field location is bits [PR101283]
    
    If the value of the DW_AT_data_member_location attribute is constant, the
    associated unit is bytes. This patch amends incorrect behaviour which was being
    exercised with -gdwarf-2. This caused some of the failures as noted in PR
    debug/101283 (specifically the BTF tests involving btm_offset).
    
    The testcase ctf-struct-array-2.c was erroneously checking for the value of
    ctm_offset in number of bytes.
    
    The patch fixes the calculation of the field location value for a struct member
    in dwarf2ctf and adjusts the testcase. This patch also fixes some of the
    failing tests as noted in PR debug/101283.
    
    2021-07-06  Indu Bhagat  <indu.bhagat@oracle.com>
    
    gcc/ChangeLog:
    
            PR debug/101283
            * dwarf2ctf.c (ctf_get_AT_data_member_location): Multiply by 8 to get
            number of bits.
    
    gcc/testsuite/ChangeLog:
    
            PR debug/101283
            * gcc.dg/debug/ctf/ctf-struct-array-2.c: Adjust the value in the testcase.

Diff:
---
 gcc/dwarf2ctf.c                                     | 4 ++--
 gcc/testsuite/gcc.dg/debug/ctf/ctf-struct-array-2.c | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/gcc/dwarf2ctf.c b/gcc/dwarf2ctf.c
index 08e12520daa..5e8a7258583 100644
--- a/gcc/dwarf2ctf.c
+++ b/gcc/dwarf2ctf.c
@@ -100,13 +100,13 @@ ctf_get_AT_data_member_location (dw_die_ref die)
 	  gcc_assert (!descr->dw_loc_oprnd2.v.val_unsigned);
 	  gcc_assert (descr->dw_loc_oprnd2.val_class
 		      == dw_val_class_unsigned_const);
-	  field_location = descr->dw_loc_oprnd1.v.val_unsigned;
+	  field_location = descr->dw_loc_oprnd1.v.val_unsigned * 8;
 	}
       else
 	{
 	  attr = get_AT (die, DW_AT_data_member_location);
 	  if (attr && AT_class (attr) == dw_val_class_const)
-	    field_location = AT_int (attr);
+	    field_location = AT_int (attr) * 8;
 	  else
 	    field_location = (get_AT_unsigned (die,
 					   DW_AT_data_member_location)
diff --git a/gcc/testsuite/gcc.dg/debug/ctf/ctf-struct-array-2.c b/gcc/testsuite/gcc.dg/debug/ctf/ctf-struct-array-2.c
index 9e698fde89e..37094b5d420 100644
--- a/gcc/testsuite/gcc.dg/debug/ctf/ctf-struct-array-2.c
+++ b/gcc/testsuite/gcc.dg/debug/ctf/ctf-struct-array-2.c
@@ -10,6 +10,6 @@
 /* { dg-final { scan-assembler-times "0x12000000\[\t \]+\[^\n\]*ctt_info" 1 } } */
 /* { dg-final { scan-assembler-times "\[\t \]0x4\[\t \]+\[^\n\]*cta_nelems" 1 } } */
 /* { dg-final { scan-assembler-times "\[\t \]0\[\t \]+\[^\n\]*ctm_offset" 1 } } */
-/* { dg-final { scan-assembler-times "\[\t \]0x4\[\t \]+\[^\n\]*ctm_offset" 1 } } */
+/* { dg-final { scan-assembler-times "\[\t \]0x20\[\t \]+\[^\n\]*ctm_offset" 1 } } */
 
 static struct ranges {int from, to;} lim_regs[] = {{ 16, 7}, { 16, 6}, { 20, 7},{ 20, 6}};