[PATCH 3/3] bpf: Corrected index computation when present with unnamed struct fields

[Cupertino Miranda]

Any unnamed structure field if not a member of the BTF_KIND_STRUCT.
For that reason, CO-RE access strings indexes should take that in
consideration. This patch adds a condition to the incrementer that
computes the index for the field access.

gcc/ChangeLog:
        * config/bpf/core-builtins.cc (bpf_core_get_index): Check if
        field contains a DECL_NAME.

gcc/testsuite/ChangeLog:
        * gcc.target/bpf/core-builtin-fieldinfo-offset-1.c: Add
        testcase for unnamed fields.
---
 gcc/config/bpf/core-builtins.cc                        |  6 +++++-
 .../gcc.target/bpf/core-builtin-fieldinfo-offset-1.c   | 10 ++++++++--
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/gcc/config/bpf/core-builtins.cc b/gcc/config/bpf/core-builtins.cc
index 70b14e48e6e5..8333ad81d0e0 100644
--- a/gcc/config/bpf/core-builtins.cc
+++ b/gcc/config/bpf/core-builtins.cc
@@ -553,7 +553,11 @@ bpf_core_get_index (const tree node, bool *valid)
        {
          if (l == node)
            return i;
-         i++;
+         /* Skip unnamed padding, not represented by BTF.  */
+         if (DECL_NAME(l) != NULL_TREE
+             || TREE_CODE (TREE_TYPE (l)) == UNION_TYPE
+             || TREE_CODE (TREE_TYPE (l)) == RECORD_TYPE)
+           i++;
        }
     }
   else if (code == ARRAY_REF || code == ARRAY_RANGE_REF || code == MEM_REF)
diff --git a/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-offset-1.c 
b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-offset-1.c
index 27654205287d..8b1d8b012a2a 100644
--- a/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-offset-1.c
+++ b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-offset-1.c
@@ -14,6 +14,9 @@ struct T {
   struct S s[2];
   char c;
   char d;
+  int a: 1;
+  int:31;
+  int f;
 };
 
 enum {
@@ -38,7 +41,9 @@ unsigned int foo (struct T *t)
   unsigned e1 = __builtin_preserve_field_info (bar()->d, FIELD_BYTE_OFFSET);
   unsigned e2 = __builtin_preserve_field_info (bar()->s[1].a4, 
FIELD_BYTE_OFFSET);
 
-  return s0a1 + s0a4 + s0x + s1a1 + s1a4 + s1x + c + d + e1 + e2;
+  unsigned f1 = __builtin_preserve_field_info (t->f, FIELD_BYTE_OFFSET);
+
+  return s0a1 + s0a4 + s0x + s1a1 + s1a4 + s1x + c + d + e1 + e2 + f1;
 }
 
 /* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],4" 2 } } */
@@ -65,5 +70,6 @@ unsigned int foo (struct T *t)
 /* { dg-final { scan-assembler-times "bpfcr_astr_off \\(\"0:1:1:4\"\\)" 1 } } 
*/
 /* { dg-final { scan-assembler-times "bpfcr_astr_off \\(\"0:2\"\\)" 1 } } */
 /* { dg-final { scan-assembler-times "bpfcr_astr_off \\(\"0:3\"\\)" 2 } } */
+/* { dg-final { scan-assembler-times "bpfcr_astr_off \\(\"0:5\"\\)" 1 } } */
 
-/* { dg-final { scan-assembler-times "0\[\t \]+\[^\n\]*bpfcr_kind" 10 } } */
+/* { dg-final { scan-assembler-times "0\[\t \]+\[^\n\]*bpfcr_kind" 11 } } */
-- 
2.30.2