[AIX][Clang][K] Create `-K` Option for AIX.

[francii]

Summary

-K is a linker option on AIX, that is used to align the header, text, data, and loader sections of the output file so
that each section begins on a page boundary.

This patch creates the -K option in clang. On non-AIX targets, the "unsupported option" error is thrown.

[francii]

nit: spacing

[francii]

Add test case

[francii]

Clean up test case

[francii]

Remove NoArgumentUnused, claim -K when checking target.

[hubert.reinterpretcast]

@francii, what happens when -K is used on a pure-compile (-c) invocation? Do we get an "unused" message? Should we be testing that?
I think we should be testing the diagnostic for the "wrong target" usage as well?

[francii]

In D146399#4243803, @hubert.reinterpretcast wrote:

@francii, what happens when -K is used on a pure-compile (-c) invocation? Do we get an "unused" message? Should we be testing that?
I think we should be testing the diagnostic for the "wrong target" usage as well?

When compiling with -c, we will get the "unused" message. I will include a test case for it.

Do we need a test case for the diagnostic? If we are only supporting one target, which triple would be used for the test?

[hubert.reinterpretcast]

In D146399#4244479, @francii wrote:

Do we need a test case for the diagnostic? If we are only supporting one target, which triple would be used for the test?

I think we do need a test case for the diagnostic. I suspect it should be in a separate file.
Unlike a lot of the options work we did for AIX, this is adding a new option (not processing an existing one).
I suggest powerpc64-unknown-linux-gnu for the triple.

[francii]

Add -c test case

[francii]

Add unsupported target test case

[daltenty]

clang/lib/Driver/ToolChains/Clang.cpp

6331

Let's not claim here, just in case this isn't a link step invocation.

[francii]

Don't claim -k when checking target

[daltenty]

LGTM, with minor fixup as noted

clang/test/Driver/aix-ld.c

1104

nit: I think you missed a conflict marker on the last update

[francii]

Remove leftover marker

clang/include/clang/Driver/Options.td

HelpText<"Add directory to SYSTEM include search path, "
            "absolute paths are relative to -isysroot">, MetaVarName<"<directory>">,
   Flags<[CC1Option]>;
 def ivfsoverlay : JoinedOrSeparate<["-"], "ivfsoverlay">, Group<clang_i_Group>, Flags<[CC1Option]>,
   HelpText<"Overlay the virtual filesystem described by file over the real file system">;
 def vfsoverlay : JoinedOrSeparate<["-", "--"], "vfsoverlay">, Flags<[CC1Option, CoreOption]>,
   HelpText<"Overlay the virtual filesystem described by file over the real file system. "
            "Additionally, pass this overlay file to the linker if it supports it">;
 def imultilib : Separate<["-"], "imultilib">, Group<gfortran_Group>;
+def K : Flag<["-"], "K">, Flags<[LinkerInput, NoArgumentUnused]>;
 def keep__private__externs : Flag<["-"], "keep_private_externs">;
 def l : JoinedOrSeparate<["-"], "l">, Flags<[LinkerInput, RenderJoined]>,
         Group<Link_Group>;
 def lazy__framework : Separate<["-"], "lazy_framework">, Flags<[LinkerInput]>;
 def lazy__library : Separate<["-"], "lazy_library">, Flags<[LinkerInput]>;
 def mlittle_endian : Flag<["-"], "mlittle-endian">, Flags<[NoXarchOption]>;
 def EL : Flag<["-"], "EL">, Alias<mlittle_endian>;
 def mbig_endian : Flag<["-"], "mbig-endian">, Flags<[NoXarchOption]>;

clang/lib/Driver/ToolChains/Clang.cpp

   if (Arg *A = Args.getLastArgNoClaim(options::OPT_p, options::OPT_pg)) {
     if (A->getOption().matches(options::OPT_p)) {
       A->claim();
       if (TC.getTriple().isOSAIX() && !Args.hasArgNoClaim(options::OPT_pg))
         CmdArgs.push_back("-pg");
     }
   }
 
+  if (Arg *A = Args.getLastArgNoClaim(options::OPT_K);
+      A && !TC.getTriple().isOSAIX())
+    D.Diag(diag::err_drv_unsupported_opt_for_target)
+        << A->getAsString(Args) << TripleStr;
+
   if (Args.getLastArg(options::OPT_fapple_kext) ||
       (Args.hasArg(options::OPT_mkernel) && types::isCXX(InputType)))
     CmdArgs.push_back("-fapple-kext");
 
   Args.AddLastArg(CmdArgs, options::OPT_altivec_src_compat);
   Args.AddLastArg(CmdArgs, options::OPT_flax_vector_conversions_EQ);
   Args.AddLastArg(CmdArgs, options::OPT_fobjc_sender_dependent_dispatch);
   Args.AddLastArg(CmdArgs, options::OPT_fdiagnostics_print_source_range_info);

clang/test/Driver/aix-ld.c

 
 // Check powerpc-ibm-aix7.1.0.0, 32-bit. -fopenmp=libfoo results an error.
 // RUN: %clang %s 2>&1 -### \
 // RUN:        --target=powerpc-ibm-aix7.1.0.0 \
 // RUN:        --sysroot %S/Inputs/aix_ppc_tree \
 // RUN:        -fopenmp=libfoo \
 // RUN:   | FileCheck --check-prefixes=CHECK-FOPENMP-FOO %s
 // CHECK-FOPENMP-FOO: error: unsupported argument 'libfoo' to option '-fopenmp='
+
+// Check powerpc-ibm-aix7.1.0.0. -K is a passthrough linker option.
+// RUN: %clang %s 2>&1 -### \
+// RUN:        --target=powerpc-ibm-aix7.1.0.0 \
+// RUN:        --sysroot %S/Inputs/aix_ppc_tree \
+// RUN:        --unwindlib=libunwind \
+// RUN:        -K \
+// RUN:   | FileCheck --check-prefixes=CHECK-K %s
+// CHECK-K:     "-cc1" "-triple" "powerpc-ibm-aix7.1.0.0"
+// CHECK-K:     "-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-K:     "{{.*}}ld{{(.exe)?}}"
+// CHECK-K:     "[[SYSROOT]]/usr/lib{{/|\\\\}}crt0.o"
+// CHECK-K:     "[[SYSROOT]]/usr/lib{{/|\\\\}}crti.o"
+// CHECK-K:     "-K"