libdw: Add dwarf_language and dwarf_language_lower_bound functions.

dwarf_language returns a DW_LNAME constant for a CU Die. If the CU Die
has a DW_AT_language_name attribute dwarf_language will return it and
the DW_AT_language_version attribute value. Otherwise dwarf_language
will lookup the (old style) DW_AT_language attribute and translate the
DW_LANG constant into a DW_LNAME constant and version using a new
static function srclang_to_language.

The dwarf_language_lower_bound function works just like the
dwarf_default_lower_bound function, but takes a DW_LNAME constant
instead of a DW_LANG constant.

Adds a new test to make sure dwarf_language_lower_bound handles all
known DW_LNAME constants.

    * NEWS: Add new functions.
    * libdw/libdw.map (ELFUTILS_0.193): New section with new functions.
    * libdw/libdw.h (dwarf_srclang): Add comment explaining this
    returns DW_LANG constants.
    (dwarf_language): New function.
    (dwarf_default_lower_bound): Add comment explaining this works on
    DW_LANG constants.
    (dwarf_language_lower_bound): New function.
    * libdw/libdwP.h: INTDECL dwarf_language and
    dwarf_language_lower_bound.
    * libdw/dwarf_srclang.c (srclang_to_language): New function.
    (dwarf_language): Likewise.
    * libdw/dwarf_default_lower_bound.c (dwarf_language_lower_bound):
    New function.
    * libdw/dwarf_getfuncs.c (dwarf_getfuncs):  Use dwarf_language and
    dwarf_language_lower_bound.
    * libdw/dwarf_aggregate_size.c (array_size): Likewise.
    * tests/dwarf_language_lower_bound.c: New test.
    * tests/Makefile.am (check_PROGRAMS): Add dwarf_language_lower_bound.
    (TESTS): Likewise.
    (dwarf_language_lower_bound_LDADD): New variable.

Signed-off-by: Mark Wielaard <[email protected]>

2 files changed, 76 insertions, 1 deletions

diff --git a/tests/Makefile.am b/tests/Makefile.am
index 335f1925..bf5a9b22 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -56,7 +56,8 @@ check_PROGRAMS = arextract arsymtest newfile saridx scnnames sectiondump \
 		  elfstrtab dwfl-proc-attach \
 		  elfshphehdr elfstrmerge dwelfgnucompressed elfgetchdr \
 		  elfgetzdata elfputzdata zstrptr emptyfile vendorelf \
-		  fillfile dwarf_default_lower_bound dwarf-die-addr-die \
+		  fillfile dwarf_default_lower_bound \
+		  dwarf_language_lower_bound dwarf-die-addr-die \
 		  get-units-invalid get-units-split attr-integrate-skel \
 		  all-dwarf-ranges unit-info next_cfi \
 		  elfcopy addsections xlate_notes elfrdwrnop \
@@ -203,6 +204,7 @@ TESTS = run-arextract.sh run-arsymtest.sh run-ar.sh newfile test-nlist \
 	run-compress-test.sh \
 	run-readelf-zdebug.sh run-readelf-zdebug-rel.sh \
 	emptyfile vendorelf fillfile dwarf_default_lower_bound \
+	dwarf_language_lower_bound \
 	run-dwarf-die-addr-die.sh \
 	run-get-units-invalid.sh run-get-units-split.sh \
 	run-attr-integrate-skel.sh \
@@ -864,6 +866,7 @@ emptyfile_LDADD = $(libelf)
 vendorelf_LDADD = $(libelf)
 fillfile_LDADD = $(libelf)
 dwarf_default_lower_bound_LDADD = $(libdw)
+dwarf_language_lower_bound_LDADD = $(libdw)
 dwarf_die_addr_die_LDADD = $(libdw)
 get_units_invalid_LDADD = $(libdw)
 get_units_split_LDADD = $(libdw)
diff --git a/tests/dwarf_language_lower_bound.c b/tests/dwarf_language_lower_bound.c
new file mode 100644
index 00000000..6bb534ac
--- /dev/null
+++ b/tests/dwarf_language_lower_bound.c
@@ -0,0 +1,72 @@
+/* Test all DW_LNAME constants are handled by dwarf_language_lower_bound.
+
+   Copyright (C) 2016 Red Hat, Inc.
+   Copyright (C) 2024, 2025 Mark J. Wielaard <[email protected]>
+   This file is part of elfutils.
+
+   This file is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   elfutils is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <dwarf.h>
+#include ELFUTILS_HEADER(dw)
+#include "../libdw/known-dwarf.h"
+
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+static void
+test_lang (const char *name, Dwarf_Word lang)
+{
+  Dwarf_Sword low;
+  int res = dwarf_language_lower_bound (lang, &low);
+
+  if (res != 0)
+    {
+      printf ("dwarf_language_lower_bound failed (%d) for %s\n", res, name);
+      exit (-1);
+    }
+
+  /* All currently known lower bounds are either zero or one, but
+     they don't have to.  Update test once one is a different value.  */
+  if (low != 0 && low != 1)
+    {
+      printf ("unexpected lower bound %" PRId64 " for %s\n", low, name);
+      exit (-1);
+    }
+
+  printf ("%s: %" PRId64 "\n", name, low);
+}
+
+int
+main (int argc __attribute__ ((unused)), char *argv[] __attribute__ ((unused)))
+{
+  Dwarf_Sword low;
+  /* Bad language code must fail.  */
+  if (dwarf_language_lower_bound (-1, &low) == 0)
+    {
+      printf ("Bad lang code -1 succeeded (%" PRId64 ")\n", low);
+      exit (-1);
+    }
+
+  /* Test all known language codes.  */
+#define DWARF_ONE_KNOWN_DW_LNAME(NAME, CODE) test_lang (#NAME, CODE);
+  DWARF_ALL_KNOWN_DW_LNAME
+#undef DWARF_ONE_KNOWN_DW_LNAME
+
+  return 0;
+}