[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

2

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

[MaskRay]

clang/lib/Driver/ToolChains/Clang.cpp

5873–5874

AArch64.

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

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

2

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

2

Just reuse CHECK-OPT

[dhoekwater]

Make a comment more accurate and simplify test command functions

[dhoekwater]

clang/lib/Driver/ToolChains/Clang.cpp

5873–5874

Nice catch, fixed.

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

2

Thanks for the feedback! Fixed.

2

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

#endif
   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)) {
     if (!A->getOption().matches(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 AArch64 ELF targets.
+      if ((Triple.isX86() || Triple.isAArch64()) && Triple.isOSBinFormatELF())
         A->render(Args, CmdArgs);
       else
         D.Diag(diag::err_drv_unsupported_opt_for_target)
             << A->getAsString(Args) << TripleStr;
     }
   }
 
   Args.AddLastArg(CmdArgs, options::OPT_finstrument_functions,

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

 // RUN: %clang -### --target=x86_64 -fprofile-use=default.profdata -fsplit-machine-functions %s 2>&1 | FileCheck %s --check-prefixes=CHECK,LTO-NEG
+// RUN: %clang -### --target=aarch64 -fprofile-use=default.profdata -fsplit-machine-functions %s 2>&1 | FileCheck %s --check-prefixes=CHECK,LTO-NEG
 // RUN: %clang -### --target=x86_64 -fprofile-use=default.profdata -fsplit-machine-functions -fno-split-machine-functions %s -c 2>&1 | FileCheck -check-prefix=NEG %s
 
 // CHECK:      "-fsplit-machine-functions"
 // CHECK-SAME: "-fprofile-instrument-use-path=default.profdata"
 
 // NEG-NOT:    "-fsplit-machine-functions"
 
 // RUN: %clang -### --target=x86_64-linux -flto -fsplit-machine-functions %s 2>&1 | FileCheck %s --check-prefix=LTO