RISC-V: Implment Tag_RISCV_x3_reg_usage

kito-cheng · Aug 18, 2023 · d13849c · d13849c
1 parent 3020782
commit d13849c
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Showing 4 changed files with 42 additions and 1 deletion.
diff --git a/bfd/elfnn-riscv.c b/bfd/elfnn-riscv.c
@@ -4024,6 +4024,21 @@ riscv_merge_attributes (bfd *ibfd, struct bfd_link_info *info)
 	    }
 	}
 	break;
+
+      case Tag_RISCV_x3_reg_usage:
+	if (in_attr[i].i > 3)
+	  _bfd_error_handler
+	    (_("error: %pB use unknown value (%d) for Tag_RISCV_x3_reg_usage."),
+	     ibfd, in_attr[i].i);
+	if (out_attr[i].i == 0 && in_attr[i].i != 3)
+	  out_attr[i].i = in_attr[i].i;
+	if (in_attr[i].i != out_attr[i].i)
+	  _bfd_error_handler
+	    (_("error: %pB has incompatible value %d "
+	       "with output %pB (%d) for Tag_RISCV_x3_reg_usage."),
+	     ibfd, in_attr[i].i, obfd, out_attr[i].i);
+	break;
+
       default:
 	result &= _bfd_elf_merge_unknown_attribute_low (ibfd, obfd, i);
       }

diff --git a/binutils/readelf.c b/binutils/readelf.c
@@ -18330,6 +18330,7 @@ static struct riscv_attr_tag_t riscv_attr_tag[] =
   T(unaligned_access),
   T(stack_align),
   T(atomic_abi),
+  T(x3_reg_usage),
 #undef T
 };
 
@@ -18404,6 +18405,29 @@ display_riscv_attribute (unsigned char *p,
 	  break;
 	}
       break;
+    case Tag_RISCV_x3_reg_usage:
+      READ_ULEB (val, p, end);
+      printf ("%" PRIu64, val);
+      switch (val)
+	{
+	case 0:
+	  printf (_("(UNKNOWN)\n"));
+	  break;
+	case 1:
+	  printf (_("('x3' as the global pointer, for relaxation purposes.)\n"));
+	  break;
+	case 2:
+	  printf (_("('x3' as the shadow stack pointer.)\n"));
+	  break;
+	case 4:
+	  printf (_("('x3' as a temporary register.)\n"));
+	  break;
+	default:
+	  printf (_("%" PRIu64 " (Unrecognized `x3` usage)\n"), val);
+	  break;
+	}
+      break;
+
     case Tag_RISCV_arch:
       p = display_tag_value (-1, p, end);
       break;

diff --git a/gas/config/tc-riscv.c b/gas/config/tc-riscv.c
@@ -5246,6 +5246,7 @@ riscv_convert_symbolic_attribute (const char *name)
     T(unaligned_access),
     T(stack_align),
     T(atomic_abi),
+    T(x3_reg_usage),
 #undef T
   };
 

diff --git a/include/elf/riscv.h b/include/elf/riscv.h
@@ -145,7 +145,8 @@ enum
   Tag_RISCV_priv_spec = 8,
   Tag_RISCV_priv_spec_minor = 10,
   Tag_RISCV_priv_spec_revision = 12,
-  Tag_RISCV_atomic_abi = 14
+  Tag_RISCV_atomic_abi = 14,
+  Tag_RISCV_x3_reg_usage = 16
 };
 
 #endif /* _ELF_RISCV_H */