2 files changed, 267 insertions, 0 deletions
diff --git a/elf/Makefile b/elf/Makefile
index d30d0ee917..3d79f40879 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -1115,6 +1115,13 @@ tests-special += $(objpfx)check-abi-ld.out
 update-abi: update-abi-ld
 update-all-abi: update-all-abi-ld
 
+tests-special += $(objpfx)tst-glibcelf.out
+$(objpfx)tst-glibcelf.out: tst-glibcelf.py elf.h $(..)/scripts/glibcelf.py \
+  $(..)/scripts/glibcextract.py
+	PYTHONPATH=$(..)scripts $(PYTHON) tst-glibcelf.py \
+          --cc="$(CC) $(patsubst -DMODULE_NAME=%,-DMODULE_NAME=testsuite,$(CPPFLAGS))" \
+	  < /dev/null > $@ 2>&1; $(evaluate-test)
+
 # The test requires shared _and_ PIE because the executable
 # unit test driver must be able to link with the shared object
 # that is going to eventually go into an installed DSO.
diff --git a/elf/tst-glibcelf.py b/elf/tst-glibcelf.py
new file mode 100644
index 0000000000..bf15a3bad4
--- /dev/null
+++ b/elf/tst-glibcelf.py
@@ -0,0 +1,260 @@
+#!/usr/bin/python3
+# Verify scripts/glibcelf.py contents against elf/elf.h.
+# Copyright (C) 2022 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+#
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# The GNU C Library 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
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <https://www.gnu.org/licenses/>.
+
+import argparse
+import enum
+import sys
+
+import glibcelf
+import glibcextract
+
+errors_encountered = 0
+
+def error(message):
+    global errors_encountered
+    sys.stdout.write('error: {}\n'.format(message))
+    errors_encountered += 1
+
+# The enum constants in glibcelf are expected to have exactly these
+# prefixes.
+expected_constant_prefixes = tuple(
+    'ELFCLASS ELFDATA EM_ ET_ DT_ PF_ PT_ SHF_ SHN_ SHT_ STB_ STT_'.split())
+
+def find_constant_prefix(name):
+    """Returns a matching prefix from expected_constant_prefixes or None."""
+    for prefix in expected_constant_prefixes:
+        if name.startswith(prefix):
+            return prefix
+    return None
+
+def find_enum_types():
+    """A generator for OpenIntEnum and IntFlag classes in glibcelf."""
+    for obj in vars(glibcelf).values():
+        if isinstance(obj, type) and obj.__bases__[0] in (
+                glibcelf._OpenIntEnum, enum.Enum, enum.IntFlag):
+            yield obj
+
+def check_duplicates():
+    """Verifies that enum types do not have duplicate values.
+
+    Different types must have different member names, too.
+
+    """
+    global_seen = {}
+    for typ in find_enum_types():
+        seen = {}
+        last = None
+        for (name, e) in typ.__members__.items():
+            if e.value in seen:
+                error('{} has {}={} and {}={}'.format(
+                    typ, seen[e.value], e.value, name, e.value))
+                last = e
+            else:
+                seen[e.value] = name
+                if last is not None and last.value > e.value:
+                    error('{} has {}={} after {}={}'.format(
+                        typ, name, e.value, last.name, last.value))
+                if name in global_seen:
+                    error('{} used in {} and {}'.format(
+                        name, global_seen[name], typ))
+                else:
+                    global_seen[name] = typ
+
+def check_constant_prefixes():
+    """Check that the constant prefixes match expected_constant_prefixes."""
+    seen = set()
+    for typ in find_enum_types():
+        typ_prefix = None
+        for val in typ:
+            prefix = find_constant_prefix(val.name)
+            if prefix is None:
+                error('constant {!r} for {} has unknown prefix'.format(
+                    val, typ))
+                break
+            elif typ_prefix is None:
+                typ_prefix = prefix
+                seen.add(typ_prefix)
+            elif prefix != typ_prefix:
+                error('prefix {!r} for constant {!r}, expected {!r}'.format(
+                    prefix, val, typ_prefix))
+        if typ_prefix is None:
+            error('empty enum type {}'.format(typ))
+
+    for prefix in sorted(set(expected_constant_prefixes) - seen):
+        error('missing constant prefix {!r}'.format(prefix))
+    # Reverse difference is already covered inside the loop.
+
+def find_elf_h_constants(cc):
+    """Returns a dictionary of relevant constants from <elf.h>."""
+    return glibcextract.compute_macro_consts(
+        source_text='#include <elf.h>',
+        cc=cc,
+        macro_re='|'.join(
+            prefix + '.*' for prefix in expected_constant_prefixes))
+
+# The first part of the pair is a name of an <elf.h> constant that is
+# dropped from glibcelf.  The second part is the constant as it is
+# used in <elf.h>.
+glibcelf_skipped_aliases = (
+    ('EM_ARC_A5', 'EM_ARC_COMPACT'),
+    ('PF_PARISC_SBP', 'PF_HP_SBP')
+)
+
+# Constants that provide little value and are not included in
+# glibcelf: *LO*/*HI* range constants, *NUM constants counting the
+# number of constants.  Also includes the alias names from
+# glibcelf_skipped_aliases.
+glibcelf_skipped_constants = frozenset(
+    [e[0] for e in glibcelf_skipped_aliases]) | frozenset("""
+DT_AARCH64_NUM
+DT_ADDRNUM
+DT_ADDRRNGHI
+DT_ADDRRNGLO
+DT_ALPHA_NUM
+DT_ENCODING
+DT_EXTRANUM
+DT_HIOS
+DT_HIPROC
+DT_IA_64_NUM
+DT_LOOS
+DT_LOPROC
+DT_MIPS_NUM
+DT_NUM
+DT_PPC64_NUM
+DT_PPC_NUM
+DT_PROCNUM
+DT_SPARC_NUM
+DT_VALNUM
+DT_VALRNGHI
+DT_VALRNGLO
+DT_VERSIONTAGNUM
+ELFCLASSNUM
+ELFDATANUM
+ET_HIOS
+ET_HIPROC
+ET_LOOS
+ET_LOPROC
+ET_NUM
+PF_MASKOS
+PF_MASKPROC
+PT_HIOS
+PT_HIPROC
+PT_HISUNW
+PT_LOOS
+PT_LOPROC
+PT_LOSUNW
+SHF_MASKOS
+SHF_MASKPROC
+SHN_HIOS
+SHN_HIPROC
+SHN_HIRESERVE
+SHN_LOOS
+SHN_LOPROC
+SHN_LORESERVE
+SHT_HIOS
+SHT_HIPROC
+SHT_HIPROC
+SHT_HISUNW
+SHT_HIUSER
+SHT_LOOS
+SHT_LOPROC
+SHT_LOSUNW
+SHT_LOUSER
+SHT_NUM
+STB_HIOS
+STB_HIPROC
+STB_LOOS
+STB_LOPROC
+STB_NUM
+STT_HIOS
+STT_HIPROC
+STT_LOOS
+STT_LOPROC
+STT_NUM
+""".strip().split())
+
+def check_constant_values(cc):
+    """Checks the values of <elf.h> constants against glibcelf."""
+
+    glibcelf_constants = {
+        e.name: e for typ in find_enum_types() for e in typ}
+    elf_h_constants = find_elf_h_constants(cc=cc)
+
+    missing_in_glibcelf = (set(elf_h_constants) - set(glibcelf_constants)
+                           - glibcelf_skipped_constants)
+    for name in sorted(missing_in_glibcelf):
+        error('constant {} is missing from glibcelf'.format(name))
+
+    unexpected_in_glibcelf = \
+        set(glibcelf_constants) & glibcelf_skipped_constants
+    for name in sorted(unexpected_in_glibcelf):
+        error('constant {} is supposed to be filtered from glibcelf'.format(
+            name))
+
+    missing_in_elf_h = set(glibcelf_constants) - set(elf_h_constants)
+    for name in sorted(missing_in_elf_h):
+        error('constant {} is missing from <elf.h>'.format(name))
+
+    expected_in_elf_h = glibcelf_skipped_constants - set(elf_h_constants)
+    for name in expected_in_elf_h:
+        error('filtered constant {} is missing from <elf.h>'.format(name))
+
+    for alias_name, name_in_glibcelf in glibcelf_skipped_aliases:
+        if name_in_glibcelf not in glibcelf_constants:
+            error('alias value {} for {} not in glibcelf'.format(
+                name_in_glibcelf, alias_name))
+        elif (int(elf_h_constants[alias_name])
+              != glibcelf_constants[name_in_glibcelf].value):
+            error('<elf.h> has {}={}, glibcelf has {}={}'.format(
+                alias_name, elf_h_constants[alias_name],
+                name_in_glibcelf, glibcelf_constants[name_in_glibcelf]))
+
+    # Check for value mismatches:
+    for name in sorted(set(glibcelf_constants) & set(elf_h_constants)):
+        glibcelf_value = glibcelf_constants[name].value
+        elf_h_value = int(elf_h_constants[name])
+        # On 32-bit architectures <elf.h> as some constants that are
+        # parsed as signed, while they are unsigned in glibcelf.  So
+        # far, this only affects some flag constants, so special-case
+        # them here.
+        if (glibcelf_value != elf_h_value
+            and not (isinstance(glibcelf_constants[name], enum.IntFlag)
+                     and glibcelf_value == 1 << 31
+                     and elf_h_value == -(1 << 31))):
+            error('{}: glibcelf has {!r}, <elf.h> has {!r}'.format(
+                name, glibcelf_value, elf_h_value))
+
+def main():
+    """The main entry point."""
+    parser = argparse.ArgumentParser(
+        description="Check glibcelf.py and elf.h against each other.")
+    parser.add_argument('--cc', metavar='CC',
+                        help='C compiler (including options) to use')
+    args = parser.parse_args()
+
+    check_duplicates()
+    check_constant_prefixes()
+    check_constant_values(cc=args.cc)
+
+    if errors_encountered > 0:
+        print("note: errors encountered:", errors_encountered)
+        sys.exit(1)
+
+if __name__ == '__main__':
+    main()