build: Add '--enable-demangling' configure option

For demangling support in the backtrace screen, which will be added in
the next commit.

Two backends will be supported: libiberty (GNU) and libdemangle
(Solaris). This commit adds checks for both of them.

Co-authored-by: Odric Roux-Paris <odric@roux-paris.fr>
Co-authored-by: Benny Baumann <BenBE@geshi.org>
Signed-off-by: Kang-Che Sung <explorer09@gmail.com>

Author: 3 people

Makefile.am

@@ -161,7 +161,8 @@ myhtopheaders = \
 	UptimeMeter.h \
 	UsersTable.h \
 	Vector.h \
-	XUtils.h
+	XUtils.h \
+	generic/ProvideDemangle.h
 
 if HAVE_BACKTRACE_SCREEN
 myhtopheaders += \

configure.ac

@@ -1304,6 +1304,139 @@ case $enable_backtrace in
 esac
 AM_CONDITIONAL([HAVE_BACKTRACE_SCREEN], [test "$enable_backtrace" != no])
 
+AC_ARG_ENABLE(
+   [demangling],
+   [AS_HELP_STRING(
+      [--enable-demangling=BACKEND],
+      [enable demangling support for backtraces; available backends: libiberty libdemangle @<:@default=check@:>@]
+   )],
+   [],
+   [enable_demangling=check]
+)
+
+demangling_backend_found=no
+have_libiberty=no
+have_libdemangle=no
+case $enable_demangling in
+   check|yes)
+      have_libiberty=check
+      have_libdemangle=check
+      ;;
+   libiberty|iberty|liberty)
+      have_libiberty=check
+      enable_demangling=libiberty
+      ;;
+   libdemangle)
+      have_libdemangle=check
+      ;;
+esac
+
+demangle_header_paths=''
+
+if test "$have_libiberty" != no; then
+   AC_CHECK_LIB(
+      [iberty],
+      [cplus_demangle],
+      [demangle_header_paths="/usr/local/include/libiberty /usr/include/libiberty"],
+      [have_libiberty=no]
+   )
+fi
+if test "$have_libdemangle" != no; then
+   AC_CHECK_LIB([demangle], [cplus_demangle], [:], [have_libdemangle=no])
+fi
+
+if test "$have_libiberty$have_libdemangle" != nono; then
+   if htop_search_header_dir demangle.h "$demangle_header_paths"; then
+      AC_DEFINE([HAVE_DEMANGLE_H], 1, [Define to 1 if you have the <demangle.h> header file.])
+   else
+      have_libdemangle=no
+      if test "$have_libiberty" != no; then
+         AC_CHECK_HEADERS([libiberty/demangle.h], [], [have_libiberty=no])
+      fi
+   fi
+fi
+
+htop_save_CPPFLAGS=$CPPFLAGS
+htop_save_LIBS=$LIBS
+CPPFLAGS="$AM_CPPFLAGS -I$srcdir $CPPFLAGS"
+
+if test "$demangling_backend_found" = no && test "$have_libiberty" != no; then
+   LIBS="-liberty $htop_save_LIBS"
+
+   AC_MSG_CHECKING([whether libiberty cplus_demangle works])
+   AC_LINK_IFELSE(
+      [AC_LANG_PROGRAM(
+         [[
+#include <stdlib.h>
+#include "generic/ProvideDemangle.h"
+/* char* cplus_demangle(const char* mangled, int options); */
+         ]], [[
+            char* demangled = cplus_demangle("", DMGL_AUTO);
+            free(demangled);
+         ]]
+      )], [
+         AC_MSG_RESULT([yes])
+         have_libiberty=yes
+         demangling_backend_found=yes
+         enable_demangling=libiberty
+         AC_DEFINE([HAVE_LIBIBERTY_CPLUS_DEMANGLE], [1], [Define to 1 if libiberty supports cplus_demangle function.])
+      ], [
+         AC_MSG_RESULT([no])
+         have_libiberty=no
+         LIBS=$htop_save_LIBS
+      ]
+   )
+fi
+
+if test "$demangling_backend_found" = no && test "$have_libdemangle" != no; then
+   LIBS="-ldemangle $htop_save_LIBS"
+
+   AC_MSG_CHECKING([whether libdemangle cplus_demangle works])
+   AC_LINK_IFELSE(
+      [AC_LANG_PROGRAM(
+         [[
+#include "generic/ProvideDemangle.h"
+/* int cplus_demangle(const char* symbol, char* interpretation, size_t size); */
+         ]], [[
+            static char demangled[1];
+            int ret = cplus_demangle("", demangled, sizeof(demangled));
+            if (ret == DEMANGLE_ENAME) {
+               ret = 0;
+            }
+            return (ret <= 0 && ret > -126 ? ret : 1);
+         ]]
+      )], [
+         AC_MSG_RESULT([yes])
+         have_libdemangle=yes
+         demangling_backend_found=yes
+         enable_demangling=libdemangle
+         AC_DEFINE([HAVE_LIBDEMANGLE_CPLUS_DEMANGLE], [1], [Define to 1 if libdemangle supports cplus_demangle function.])
+      ], [
+         AC_MSG_RESULT([no])
+         have_libdemangle=no
+         LIBS=$htop_save_LIBS
+      ]
+   )
+fi
+
+CPPFLAGS=$htop_save_CPPFLAGS
+
+case $enable_demangling in
+   no|check)
+      enable_demangling=no
+      ;;
+   yes)
+      AC_MSG_ERROR([did not find any backend for --enable-demangling])
+      ;;
+   *)
+      if test "$demangling_backend_found" = no; then
+         AC_MSG_ERROR([backend '$enable_demangling' for --enable-demangling is not supported or not found])
+      fi
+      AC_DEFINE([HAVE_DEMANGLING], [1], [Define to 1 if the demangling is supported.])
+      ;;
+esac
+AM_CONDITIONAL([HAVE_DEMANGLING], [test "$have_demangling" != no])
+
 AC_ARG_ENABLE(
    [hwloc],
    [AS_HELP_STRING(
@@ -1740,6 +1873,7 @@ AC_MSG_RESULT([
   unicode:                   $enable_unicode
   affinity:                  $enable_affinity
   backtrace:                 $enable_backtrace
+  demangling:                $enable_demangling
   hwloc:                     $enable_hwloc
   debug:                     $enable_debug
   static:                    $enable_static

generic/ProvideDemangle.h

@@ -0,0 +1,33 @@
+#ifndef HEADER_ProvideDemangle
+#define HEADER_ProvideDemangle
+/*
+htop - generic/ProvideDemangle.h
+(C) 2026 htop dev team
+Released under the GNU GPLv2+, see the COPYING file
+in the source distribution for its full text.
+*/
+
+// IWYU pragma: no_include "config.h"
+
+// IWYU pragma: begin_exports
+
+#if !defined(HAVE_DECL_BASENAME)
+// Suppress libiberty's own declaration of basename().
+// It's a pity that we need this workaround as libiberty developers
+// refuse fix their headers and export an unwanted interface to us.
+// htop doesn't use basename() API. (The POSIX version is flawed by
+// design; libiberty's ships with GNU version of basename() that's
+// incompatible with POSIX.)
+// <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122729>
+#define HAVE_DECL_BASENAME 1
+#endif
+
+#if defined(HAVE_DEMANGLE_H)
+#include <demangle.h>
+#elif defined(HAVE_LIBIBERTY_DEMANGLE_H)
+#include <libiberty/demangle.h>
+#endif
+
+// IWYU pragma: end_exports
+
+#endif /* HEADER_ProvideDemangle */