Ticket #54773: patch-use-libcxx.diff

incpath.c

@@ -129 +129 @@
   int relocated = cpp_relocated ();
   size_t len;
 
+  if (cxx_stdinc)
+    {
+      if (!getenv("LIBCPP_INCLUDE_PATH") && !getenv("GCC_FORCE_LIBSTDCPP"))
+        {
+          add_path (xstrdup ("@LLVMHEADERPATH@"), SYSTEM, true, false);
+        }
+    }
   if (iprefix && (len = cpp_GCC_INCLUDE_DIR_len) != 0)
     {
       /* Look for directories that start with the standard prefix.
@@ -474 +481 @@
   /* CPATH and language-dependent environment variables may add to the
      include chain.  */
   add_env_var_paths ("CPATH", BRACKET);
+  if (stdinc && cxx_stdinc && !getenv("GCC_FORCE_LIBSTDCPP"))
+    add_env_var_paths ("LIBCPP_INCLUDE_PATH", SYSTEM);
   add_env_var_paths (lang_env_vars[idx], SYSTEM);
 
   target_c_incpath.extra_pre_includes (sysroot, iprefix, stdinc);

g++spec.c

@@ -48 +48 @@
 #ifndef LIBSTDCXX
 #define LIBSTDCXX "stdc++"
 #endif
+// libc++ support:
+#ifndef LIBCXX
+#define LIBCXX "c++"
+#define LIBCXXABI "c++abi"
+// using libsupc++ is a hack, probably to be dropped on systems that have a new enough libc++
+// which has `operator delete(void*, unsigned long)`
+#define LIBSUPCXX "supc++"
+#endif
 #ifndef LIBSTDCXX_PROFILE
 #define LIBSTDCXX_PROFILE LIBSTDCXX
 #endif
+
 #ifndef LIBSTDCXX_STATIC
 #define LIBSTDCXX_STATIC NULL
 #endif
@@ -342 +351 @@
           j++;
         }
 #endif
-      generate_option (OPT_l,
-                       saw_profile_flag ? LIBSTDCXX_PROFILE : LIBSTDCXX, 1,
-                       CL_DRIVER, &new_decoded_options[j]);
-      added_libraries++;
-      j++;
-      /* Add target-dependent static library, if necessary.  */
-      if ((static_link || library > 1) && LIBSTDCXX_STATIC != NULL)
+    // NOT checking for the existence of LIBCXXABI and LIBSUPCXX on purpose
+         if (getenv ("GCC_FORCE_LIBSTDCPP")) {
+                 fprintf(stderr, "GCC_FORCE_LIBSTDCPP - using -l%s instead of -l%s -l%s -l%s\n",
+                 (saw_profile_flag ? LIBSTDCXX_PROFILE : LIBSTDCXX), LIBCXX, LIBCXXABI, LIBSUPCXX);
+                 generate_option (OPT_l,
+                                  saw_profile_flag ? LIBSTDCXX_PROFILE : LIBSTDCXX, 1,
+                                  CL_DRIVER, &new_decoded_options[j]);
+                 added_libraries++;
+                 j++;
+         } else {
+                 generate_option (OPT_l, LIBCXX, 1,
+                                  CL_DRIVER, &new_decoded_options[j]);
+                 added_libraries++;
+                 j++;
+                 // add -lc++abi and -lsupc++
+                 generate_option (OPT_l, LIBCXXABI, 1,
+                                  CL_DRIVER, &new_decoded_options[j]);
+                 added_libraries++;
+                 j++;
+                 generate_option (OPT_l, LIBSUPCXX, 1,
+                                  CL_DRIVER, &new_decoded_options[j]);
+                 added_libraries++;
+                 j++;
+         }
+         /* Add target-dependent static library, if necessary.  */
+         if ((static_link || library > 1) && (LIBSTDCXX_STATIC != NULL || getenv("GCC_IS_BUILDING_ITSELF")))
         {
-          generate_option (OPT_l, LIBSTDCXX_STATIC, 1,
+          generate_option (OPT_l, LIBSTDCXX_STATIC ? LIBSTDCXX_STATIC : LIBSTDCXX, 1,
                            CL_DRIVER, &new_decoded_options[j]);
           added_libraries++;
           j++;