Bug 1467337 - Don't allow --enable-stdcxx-compat when the linker is gold. r=nalexander

Differential Revision: https://phabricator.services.mozilla.com/D197352

build/moz.configure/toolchain.configure

@@ -1641,6 +1641,31 @@ def cxx_is_icecream(info, ccache_prefix):
 set_config("CXX_IS_ICECREAM", cxx_is_icecream)
 
 
+# Libstdc++ compatibility hacks
+# ==============================================================
+#
+@depends(target, host)
+def target_or_host_is_linux(target, host):
+    return any(t.os == "GNU" and t.kernel == "Linux" for t in (target, host))
+
+
+option(
+    "--enable-stdcxx-compat",
+    env="MOZ_STDCXX_COMPAT",
+    help="Enable compatibility with older libstdc++",
+    when=target_or_host_is_linux,
+)
+
+
+@depends("--enable-stdcxx-compat", when=target_or_host_is_linux)
+def stdcxx_compat(value):
+    if value:
+        return True
+
+
+set_config("MOZ_STDCXX_COMPAT", True, when=stdcxx_compat)
+
+
 # Linker detection
 # ==============================================================
 # The policy is as follows:
@@ -1703,6 +1728,7 @@ def select_linker_tmpl(host_or_target):
             developer_options,
             extra_toolchain_flags,
             target,
+            stdcxx_compat,
             when=is_linker_option_enabled,
         )
         host_or_target_str = "target"
@@ -1713,6 +1739,7 @@ def select_linker_tmpl(host_or_target):
             developer_options,
             dependable(None),
             host,
+            stdcxx_compat,
             when=is_not_winnt_or_sunos(host_or_target),
         )
         host_or_target_str = "host"
@@ -1721,7 +1748,9 @@ def select_linker_tmpl(host_or_target):
     @checking(f"for {host_or_target_str} linker", lambda x: x.KIND)
     @imports("os")
     @imports("shutil")
-    def select_linker(linker, c_compiler, developer_options, toolchain_flags, target):
+    def select_linker(
+        linker, c_compiler, developer_options, toolchain_flags, target, stdcxx_compat
+    ):
         if linker:
             linker = linker[0]
         else:
@@ -1827,7 +1856,7 @@ def select_linker_tmpl(host_or_target):
         ):
             result = try_linker("lld")
 
-        if result is None and developer_options:
+        if result is None and developer_options and not stdcxx_compat:
             result = try_linker("gold")
 
         if result is None:
@@ -1836,6 +1865,9 @@ def select_linker_tmpl(host_or_target):
         if result is None:
             die("Failed to find an adequate linker")
 
+        if stdcxx_compat and result.KIND == "gold":
+            die("--enable-stdcxx-compat is not compatible with the gold linker")
+
         # If an explicit linker was given, error out if what we found is different.
         if linker and not linker.startswith(result.KIND):
             die("Could not use {} as linker".format(linker))
@@ -2797,30 +2829,8 @@ add_old_configure_assignment(
     "ENABLE_MOZSEARCH_PLUGIN", depends_if("--enable-mozsearch-plugin")(lambda _: True)
 )
 
-
-# Libstdc++ compatibility hacks
+# Use the old libstdc++ ABI
 # ==============================================================
-#
-@depends(target, host)
-def target_or_host_is_linux(target, host):
-    return any(t.os == "GNU" and t.kernel == "Linux" for t in (target, host))
-
-
-option(
-    "--enable-stdcxx-compat",
-    env="MOZ_STDCXX_COMPAT",
-    help="Enable compatibility with older libstdc++",
-    when=target_or_host_is_linux,
-)
-
-
-@depends("--enable-stdcxx-compat", when=target_or_host_is_linux)
-def stdcxx_compat(value):
-    if value:
-        return True
-
-
-set_config("MOZ_STDCXX_COMPAT", True, when=stdcxx_compat)
 add_flag(
     "-D_GLIBCXX_USE_CXX11_ABI=0",
     cxx_compiler,