[clang] Add clang support for Machine Function Splitting on AArch64

[dhoekwater]

Summary

On x86 targets, -fsplit-machine-functions enables splitting of machine
functions using profile information. This patch rolls out the flag for
AArch64 targets.

Depends on D158647

[mingmingl]

clang/test/Driver/fsplit-machine-functions.c

4

nit: would -target aarch64 be sufficient here? if yes it's more general.

[MaskRay]

clang/lib/Driver/ToolChains/Clang.cpp

5852

AArch64.

Arm can mean AArch32 (often written as "ARM").

clang/test/Driver/fsplit-machine-functions.c

4

Use --target= for new tests. --target=aarch64 is sufficient and preferred for generic ELF features.

9

Just reuse CHECK-OPT

[dhoekwater]

Make a comment more accurate and simplify test command functions

[dhoekwater]

clang/lib/Driver/ToolChains/Clang.cpp

5852

Nice catch, fixed.

clang/test/Driver/fsplit-machine-functions.c

4

Thanks for the feedback! Fixed.

9

Fixed.

[dhoekwater]

Rebase onto main

[dhoekwater]

Hopefully get rid of a dead dependency

[dhoekwater]

Remove a dependency to see if that fixes things.

[dhoekwater]

Add the old dependency to hopefully get the change to propagate when I remove it

[dhoekwater]

Remove the dependency again

clang/lib/Driver/ToolChains/Clang.cpp

Args.addOptInFlag(CmdArgs, options::OPT_funique_internal_linkage_names,
                     options::OPT_fno_unique_internal_linkage_names);
   Args.addOptInFlag(CmdArgs, options::OPT_funique_basic_block_section_names,
                     options::OPT_fno_unique_basic_block_section_names);
   Args.addOptInFlag(CmdArgs, options::OPT_fconvergent_functions,
                     options::OPT_fno_convergent_functions);
 
   if (Arg *A = Args.getLastArg(options::OPT_fsplit_machine_functions,
                                options::OPT_fno_split_machine_functions)) {
-    // This codegen pass is only available on x86-elf targets.
-    if (Triple.isX86() && Triple.isOSBinFormatELF()) {
+    // This codegen pass is only available on x86 and Arm ELF targets.
+    if ((Triple.isX86() || Triple.isAArch64()) && Triple.isOSBinFormatELF()) {
       if (A->getOption().matches(options::OPT_fsplit_machine_functions))
         A->render(Args, CmdArgs);
     } else {
       D.Diag(diag::err_drv_unsupported_opt_for_target)
           << A->getAsString(Args) << TripleStr;
     }
   }
 

clang/test/Driver/fsplit-machine-functions.c

 // RUN: %clang -### -target x86_64 -fprofile-use=default.profdata -fsplit-machine-functions %s -c 2>&1 | FileCheck -check-prefix=CHECK-OPT %s
 // RUN: %clang -### -target x86_64 -fsplit-machine-functions %s -c 2>&1 | FileCheck -check-prefix=CHECK-OPT %s
 // RUN: %clang -### -target x86_64 -fprofile-use=default.profdata -fsplit-machine-functions -fno-split-machine-functions %s -c 2>&1 | FileCheck -check-prefix=CHECK-NOOPT %s
+// RUN: %clang -### -target aarch64-unknown-linux -fprofile-use=default.profdata -fsplit-machine-functions %s -c 2>&1 | FileCheck -check-prefix=CHECK-AARCH64 %s
 // RUN: not %clang -c -target arm-unknown-linux -fsplit-machine-functions %s 2>&1 | FileCheck -check-prefix=CHECK-TRIPLE %s
 
 // CHECK-OPT:       "-fsplit-machine-functions"
 // CHECK-NOOPT-NOT: "-fsplit-machine-functions"
+// CHECK-AARCH64:   "-fsplit-machine-functions"
 // CHECK-TRIPLE:    error: unsupported option '-fsplit-machine-functions' for target