[Driver] Disable -faddrsig on Gentoo by default

[mgorny]

Summary

Gentoo supports combining clang toolchain with GNU binutils, and many
users actually do that. As -faddrsig is not supported by GNU strip,
this results in a lot of warnings. Disable it by default and let users
enable it explicitly if they want it; with the intent of reevaluating
when the underlying feature becomes standarized.

[phosek]

Just a comment regarding the description, are you sure it's GNU strip and not as?

[mgorny]

In D56047#1340303, @phosek wrote:

Just a comment regarding the description, are you sure it's GNU strip and not as?

Yes. https://bugs.gentoo.org/667854

[krytarowski]

It was disabled on NetBSD for the same reason - GNU strip(1) is breaking: http://netbsd.org/~kamil/llvm/strip.txt

[phosek]

LGTM, would it be possible to also include https://bugs.gentoo.org/667854 in the commit message for reference?

[mgorny]

In D56047#1340337, @phosek wrote:

LGTM, would it be possible to also include https://bugs.gentoo.org/667854 in the commit message for reference?

Done, and thanks for the review.

lib/Driver/ToolChains/Clang.cpp

 #include "CommonArgs.h"
 #include "Hexagon.h"
 #include "InputInfo.h"
 #include "PS4CPU.h"
 #include "clang/Basic/CharInfo.h"
 #include "clang/Basic/LangOptions.h"
 #include "clang/Basic/ObjCRuntime.h"
 #include "clang/Basic/Version.h"
+#include "clang/Driver/Distro.h"
 #include "clang/Driver/DriverDiagnostic.h"
 #include "clang/Driver/Options.h"
 #include "clang/Driver/SanitizerArgs.h"
 #include "clang/Driver/XRayArgs.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Config/llvm-config.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/Support/CodeGen.h"
if (Arg *A = Args.getLastArg(options::OPT_moutline,
     }
   }
 
   if (Args.hasFlag(options::OPT_faddrsig, options::OPT_fno_addrsig,
                    (TC.getTriple().isOSBinFormatELF() ||
                     TC.getTriple().isOSBinFormatCOFF()) &&
                       !TC.getTriple().isPS4() &&
                       !TC.getTriple().isOSNetBSD() &&
+                      !Distro(D.getVFS()).IsGentoo() &&
                        TC.useIntegratedAs()))
     CmdArgs.push_back("-faddrsig");
 
   // Finally add the compile command to the compilation.
   if (Args.hasArg(options::OPT__SLASH_fallback) &&
       Output.getType() == types::TY_Object &&
       (InputType == types::TY_C || InputType == types::TY_CXX)) {
     auto CLCommand =

test/Driver/addrsig.c

+// Gentoo disables -faddrsig by default
+// XFAIL: gentoo
+
 // RUN: %clang -### -target x86_64-unknown-linux -c %s 2>&1 | FileCheck -check-prefix=ADDRSIG %s
 // RUN: %clang -### -target x86_64-pc-win32 -c %s 2>&1 | FileCheck -check-prefix=ADDRSIG %s
 // RUN: %clang -### -target x86_64-unknown-linux -fno-integrated-as -c %s 2>&1 | FileCheck -check-prefix=NO-ADDRSIG %s
 // RUN: %clang -### -target x86_64-unknown-linux -fno-integrated-as -faddrsig -c %s 2>&1 | FileCheck -check-prefix=ADDRSIG %s
 // RUN: %clang -### -target x86_64-unknown-linux -fno-addrsig -c %s 2>&1 | FileCheck -check-prefix=NO-ADDRSIG %s
 // RUN: %clang -### -target x86_64-apple-darwin -c %s 2>&1 | FileCheck -check-prefix=NO-ADDRSIG %s
 // RUN: %clang -### -target x86_64-scei-ps4 -c %s 2>&1 | FileCheck -check-prefix=NO-ADDRSIG %s
 
 // ADDRSIG: -faddrsig
 // NO-ADDRSIG-NOT: -faddrsig

test/lit.cfg.py

 run_console_tests = int(lit_config.params.get('enable_console', '0'))
 if run_console_tests != 0:
     config.available_features.add('console')
 
 lit.util.usePlatformSdkOnDarwin(config, lit_config)
 macOSSDKVersion = lit.util.findPlatformSdkVersionOnMacOS(config, lit_config)
 if macOSSDKVersion is not None:
     config.available_features.add('macos-sdk-' + macOSSDKVersion)
+
+if os.path.exists('/etc/gentoo-release'):
+    config.available_features.add('gentoo')