[lld] add context-sensitive PGO options for MachO

[ellis]

Summary

Enable support for CSPGO for lld MachO targets.

Since lld MachO does not support -plugin-opt=, we need to create the --cs-profile-generate and --cs-profile-path= options and propagate them in Darwin.cpp. These flags are not supported by ld64.

Also outline code into getLastCSProfileGenerateArg() to share between CommonArgs.cpp and Darwin.cpp.

CSPGO is already implemented for ELF (https://reviews.llvm.org/D56675) and COFF (https://reviews.llvm.org/D98763).

[ellis]

Only pass flags when using lld

[MaskRay]

clang/lib/Driver/ToolChains/CommonArgs.cpp

1342

Similar code in Clang.cpp addPGOAndCoverageFlags can be replaced by this function.

clang/lib/Driver/ToolChains/Darwin.cpp

459

String literal doesn't need MakeArgString

clang/test/Driver/cspgo-lto.c

8

Prefer --target= to deprecated/legacy (since clang 3.x) -target

lld/MachO/Driver.cpp

1640

This needs a lld/test/MachO test. The ELF patch unfortunately doesn't add a test and I failed to notice it.

[ellis]

Add test to check that PGOInstrumentationGen(Use) are run

[int3]

lld/test/MachO/cspgo-gen.ll

13

doesn't *really* matter since you are creating a dylib, but lld-macho doesn't actually treat _start as a special symbol (only main). maybe rename to foo to be less misleading?

[ellis]

Rename test function to foo since _start is not a necessary symbol

[ellis]

Fix paths in clang test to support windows

clang/lib/Driver/ToolChains/Clang.cpp

static void addPGOAndCoverageFlags(const ToolChain &TC, Compilation &C,
   const Driver &D = TC.getDriver();
   auto *PGOGenerateArg = Args.getLastArg(options::OPT_fprofile_generate,
                                          options::OPT_fprofile_generate_EQ,
                                          options::OPT_fno_profile_generate);
   if (PGOGenerateArg &&
       PGOGenerateArg->getOption().matches(options::OPT_fno_profile_generate))
     PGOGenerateArg = nullptr;
 
-  auto *CSPGOGenerateArg = Args.getLastArg(options::OPT_fcs_profile_generate,
-                                           options::OPT_fcs_profile_generate_EQ,
-                                           options::OPT_fno_profile_generate);
-  if (CSPGOGenerateArg &&
-      CSPGOGenerateArg->getOption().matches(options::OPT_fno_profile_generate))
-    CSPGOGenerateArg = nullptr;
+  auto *CSPGOGenerateArg = getLastCSProfileGenerateArg(Args);
 
   auto *ProfileGenerateArg = Args.getLastArg(
       options::OPT_fprofile_instr_generate,
       options::OPT_fprofile_instr_generate_EQ,
       options::OPT_fno_profile_instr_generate);
   if (ProfileGenerateArg &&
       ProfileGenerateArg->getOption().matches(
           options::OPT_fno_profile_instr_generate))

clang/lib/Driver/ToolChains/CommonArgs.h

void addFortranRuntimeLibraryPath(const ToolChain &TC,
                                   const llvm::opt::ArgList &Args,
                                   llvm::opt::ArgStringList &CmdArgs);
 
 void addHIPRuntimeLibArgs(const ToolChain &TC, const llvm::opt::ArgList &Args,
                           llvm::opt::ArgStringList &CmdArgs);
 
 const char *getAsNeededOption(const ToolChain &TC, bool as_needed);
 
+llvm::opt::Arg *getLastCSProfileGenerateArg(const llvm::opt::ArgList &Args);
 llvm::opt::Arg *getLastProfileUseArg(const llvm::opt::ArgList &Args);
 llvm::opt::Arg *getLastProfileSampleUseArg(const llvm::opt::ArgList &Args);
 
 bool isObjCAutoRefCount(const llvm::opt::ArgList &Args);
 
 llvm::StringRef getLTOParallelism(const llvm::opt::ArgList &Args,
                                   const Driver &D);
 

clang/lib/Driver/ToolChains/CommonArgs.cpp

if (Arg *A = getLastProfileSampleUseArg(Args)) {
     StringRef FName = A->getValue();
     if (!llvm::sys::fs::exists(FName))
       D.Diag(diag::err_drv_no_such_file) << FName;
     else
       CmdArgs.push_back(Args.MakeArgString(Twine(PluginOptPrefix) +
                                            "sample-profile=" + FName));
   }
 
-  auto *CSPGOGenerateArg = Args.getLastArg(options::OPT_fcs_profile_generate,
-                                           options::OPT_fcs_profile_generate_EQ,
-                                           options::OPT_fno_profile_generate);
-  if (CSPGOGenerateArg &&
-      CSPGOGenerateArg->getOption().matches(options::OPT_fno_profile_generate))
-    CSPGOGenerateArg = nullptr;
-
-  auto *ProfileUseArg = getLastProfileUseArg(Args);
-
-  if (CSPGOGenerateArg) {
+  if (auto *CSPGOGenerateArg = getLastCSProfileGenerateArg(Args)) {
     CmdArgs.push_back(Args.MakeArgString(Twine(PluginOptPrefix) + ExtraDash +
                                          "cs-profile-generate"));
     if (CSPGOGenerateArg->getOption().matches(
             options::OPT_fcs_profile_generate_EQ)) {
       SmallString<128> Path(CSPGOGenerateArg->getValue());
       llvm::sys::path::append(Path, "default_%m.profraw");
       CmdArgs.push_back(Args.MakeArgString(Twine(PluginOptPrefix) + ExtraDash +
                                            "cs-profile-path=" + Path));
     } else
       CmdArgs.push_back(
           Args.MakeArgString(Twine(PluginOptPrefix) + ExtraDash +
                              "cs-profile-path=default_%m.profraw"));
-  } else if (ProfileUseArg) {
+  } else if (auto *ProfileUseArg = getLastProfileUseArg(Args)) {
     SmallString<128> Path(
         ProfileUseArg->getNumValues() == 0 ? "" : ProfileUseArg->getValue());
     if (Path.empty() || llvm::sys::fs::is_directory(Path))
       llvm::sys::path::append(Path, "default.profdata");
     CmdArgs.push_back(Args.MakeArgString(Twine(PluginOptPrefix) + ExtraDash +
                                          "cs-profile-path=" + Path));
   }
 

 void tools::claimNoWarnArgs(const ArgList &Args) {
   // Don't warn about unused -f(no-)?lto.  This can happen when we're
   // preprocessing, precompiling or assembling.
   Args.ClaimAllArgs(options::OPT_flto_EQ);
   Args.ClaimAllArgs(options::OPT_flto);
   Args.ClaimAllArgs(options::OPT_fno_lto);
 }
 
+Arg *tools::getLastCSProfileGenerateArg(const ArgList &Args) {
+  auto *CSPGOGenerateArg = Args.getLastArg(options::OPT_fcs_profile_generate,
+                                           options::OPT_fcs_profile_generate_EQ,
+                                           options::OPT_fno_profile_generate);
+  if (CSPGOGenerateArg &&
+      CSPGOGenerateArg->getOption().matches(options::OPT_fno_profile_generate))
+    CSPGOGenerateArg = nullptr;
+
+  return CSPGOGenerateArg;
+}
+
 Arg *tools::getLastProfileUseArg(const ArgList &Args) {
   auto *ProfileUseArg = Args.getLastArg(
       options::OPT_fprofile_instr_use, options::OPT_fprofile_instr_use_EQ,
       options::OPT_fprofile_use, options::OPT_fprofile_use_EQ,
       options::OPT_fno_profile_instr_use);
 
   if (ProfileUseArg &&
       ProfileUseArg->getOption().matches(options::OPT_fno_profile_instr_use))

clang/lib/Driver/ToolChains/Darwin.cpp

void darwin::Linker::AddLinkArgs(Compilation &C, const ArgList &Args,
   Args.AddAllArgs(CmdArgs, options::OPT_sectalign);
   Args.AddAllArgs(CmdArgs, options::OPT_sectobjectsymbols);
   Args.AddAllArgs(CmdArgs, options::OPT_segcreate);
   Args.AddLastArg(CmdArgs, options::OPT_why_load);
   Args.AddLastArg(CmdArgs, options::OPT_whatsloaded);
   Args.AddAllArgs(CmdArgs, options::OPT_dylinker__install__name);
   Args.AddLastArg(CmdArgs, options::OPT_dylinker);
   Args.AddLastArg(CmdArgs, options::OPT_Mach);
+
+  if (LinkerIsLLD) {
+    if (auto *CSPGOGenerateArg = getLastCSProfileGenerateArg(Args)) {
+      SmallString<128> Path(CSPGOGenerateArg->getNumValues() == 0
+                                ? ""
+                                : CSPGOGenerateArg->getValue());
+      llvm::sys::path::append(Path, "default_%m.profraw");
+      CmdArgs.push_back("--cs-profile-generate");
+      CmdArgs.push_back(Args.MakeArgString(Twine("--cs-profile-path=") + Path));
+    } else if (auto *ProfileUseArg = getLastProfileUseArg(Args)) {
+      SmallString<128> Path(
+          ProfileUseArg->getNumValues() == 0 ? "" : ProfileUseArg->getValue());
+      if (Path.empty() || llvm::sys::fs::is_directory(Path))
+        llvm::sys::path::append(Path, "default.profdata");
+      CmdArgs.push_back(Args.MakeArgString(Twine("--cs-profile-path=") + Path));
+    }
+  }
 }
 
 /// Determine whether we are linking the ObjC runtime.
 static bool isObjCRuntimeLinked(const ArgList &Args) {
   if (isObjCAutoRefCount(Args)) {
     Args.ClaimAllArgs(options::OPT_fobjc_link_runtime);
     return true;
   }

clang/test/Driver/cspgo-lto.c

 // RUN: touch %t.o
 //
 // RUN: %clang --target=x86_64-unknown-linux -### %t.o -flto=thin \
 // RUN:   -fprofile-use 2>&1 | FileCheck %s
 
 // CHECK: -plugin-opt=cs-profile-path=default.profdata
+
+// RUN: %clang --target=apple-arm64-ios -### %t.o -flto=thin -fuse-ld=lld -fprofile-use 2>&1 | FileCheck %s --check-prefix=DARWIN-USE1
+// RUN: %clang --target=apple-arm64-ios -### %t.o -flto=thin -fuse-ld=lld -fprofile-use=a.profdata 2>&1 | FileCheck %s --check-prefix=DARWIN-USE2
+
+// DARWIN-USE1: "--cs-profile-path=default.profdata"
+// DARWIN-USE2: "--cs-profile-path=a.profdata"
+
+// RUN: %clang --target=apple-arm64-ios -### %t.o -flto=thin -fuse-ld=lld -fcs-profile-generate 2>&1 | FileCheck %s --check-prefix=DARWIN-GEN1
+// RUN: %clang --target=apple-arm64-ios -### %t.o -flto=thin -fuse-ld=lld -fcs-profile-generate=/dump/here 2>&1 | FileCheck %s --check-prefix=DARWIN-GEN2
+
+// DARWIN-GEN1: "--cs-profile-generate"
+// DARWIN-GEN1-SAME: "--cs-profile-path=default_%m.profraw"
+// DARWIN-GEN2: "--cs-profile-generate"
+// DARWIN-GEN2-SAME: "--cs-profile-path=/dump/here/default_%m.profraw"

lld/MachO/Config.h

struct Configuration {
   std::vector<std::string> astPaths;
   std::vector<Symbol *> explicitUndefineds;
   llvm::StringSet<> explicitDynamicLookups;
   // There are typically few custom sectionAlignments or segmentProtections,
   // so use a vector instead of a map.
   std::vector<SectionAlign> sectionAlignments;
   std::vector<SegmentProtection> segmentProtections;
   bool ltoDebugPassManager = false;
+  bool csProfileGenerate = false;
+  llvm::StringRef csProfilePath;
 
   bool callGraphProfileSort = false;
   llvm::StringRef printSymbolOrder;
 
   SectionRenameMap sectionRenameMap;
   SegmentRenameMap segmentRenameMap;
 
   bool hasExplicitExports = false;

lld/MachO/Driver.cpp

bool macho::link(ArrayRef<const char *> argsArr, llvm::raw_ostream &stdoutOS,
   config->printSymbolOrder = args.getLastArgValue(OPT_print_symbol_order_eq);
   config->forceExactCpuSubtypeMatch =
       getenv("LD_DYLIB_CPU_SUBTYPES_MUST_MATCH");
   config->objcStubsMode = getObjCStubsMode(args);
   config->ignoreAutoLink = args.hasArg(OPT_ignore_auto_link);
   for (const Arg *arg : args.filtered(OPT_ignore_auto_link_option))
     config->ignoreAutoLinkOptions.insert(arg->getValue());
   config->strictAutoLink = args.hasArg(OPT_strict_auto_link);
   config->ltoDebugPassManager = args.hasArg(OPT_lto_debug_pass_manager);
+  config->csProfileGenerate = args.hasArg(OPT_cs_profile_generate);
+  config->csProfilePath = args.getLastArgValue(OPT_cs_profile_path);
 
   for (const Arg *arg : args.filtered(OPT_alias)) {
     config->aliasedSymbols.push_back(
         std::make_pair(arg->getValue(0), arg->getValue(1)));
   }
 
   if (const char *zero = getenv("ZERO_AR_DATE"))
     config->zeroModTime = strcmp(zero, "0") != 0;

lld/MachO/LTO.cpp

c.PreCodeGenPassesHook = [](legacy::PassManager &pm) {
     pm.add(createObjCARCContractPass());
   };
 
   c.AlwaysEmitRegularLTOObj = !config->ltoObjPath.empty();
 
   c.TimeTraceEnabled = config->timeTraceEnabled;
   c.TimeTraceGranularity = config->timeTraceGranularity;
   c.DebugPassManager = config->ltoDebugPassManager;
+  c.CSIRProfile = std::string(config->csProfilePath);
+  c.RunCSIRInstr = config->csProfileGenerate;
   c.OptLevel = config->ltoo;
   c.CGOptLevel = config->ltoCgo;
   if (config->saveTemps)
     checkError(c.addSaveTemps(config->outputFile.str() + ".",
                               /*UseInputModulePath=*/true));
   return c;
 }
 

lld/MachO/Options.td

 def strict_auto_link : Flag<["--"], "strict-auto-link">,
     HelpText<"Always warn for missing frameworks or libraries if they are loaded via LC_LINKER_OPTIONS">,
     Group<grp_lld>;
 def check_category_conflicts : Flag<["--"], "check-category-conflicts">,
     HelpText<"Check for conflicts between category & class methods">,
     Group<grp_lld>;
 def lto_debug_pass_manager: Flag<["--"], "lto-debug-pass-manager">,
     HelpText<"Debug new pass manager">, Group<grp_lld>;
+def cs_profile_generate: Flag<["--"], "cs-profile-generate">,
+    HelpText<"Perform context senstive PGO instrumentation">, Group<grp_lld>;
+def cs_profile_path: Joined<["--"], "cs-profile-path=">,
+    HelpText<"Context sensitive profile file path">, Group<grp_lld>;
 
 // This is a complete Options.td compiled from Apple's ld(1) manpage
 // dated 2018-03-07 and cross checked with ld64 source code in repo
 // https://github.com/apple-opensource/ld64 at git tag "512.4" dated
 // 2018-03-18.
 
 // Flags<[HelpHidden]> marks options that are not yet ported to lld,
 // and serve as a scoreboard for annotating our progress toward

lld/test/MachO/cspgo-gen.ll

+; REQUIRES: x86
+
+; RUN: llvm-as %s -o %t.o
+; RUN: %lld -dylib --cs-profile-generate --cs-profile-path=default_%m.profraw %t.o -o %t --lto-debug-pass-manager 2>&1 | FileCheck %s --implicit-check-not=PGOInstrumentation
+
+; CHECK: PGOInstrumentationGen
+
+target triple = "x86_64-apple-darwin"
+target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+
+@__llvm_profile_runtime = global i32 0, align 4
+
+define void @_start() {
+entry:
+  ret void
+}

lld/test/MachO/cspgo-use.ll

+; REQUIRES: x86
+
+; Create an empty profile
+; RUN: echo > %t.proftext
+; RUN: llvm-profdata merge %t.proftext -o %t.profdata
+
+; RUN: llvm-as %s -o %t.o
+; RUN: %lld -dylib --cs-profile-path=%t.profdata %t.o -o %t --lto-debug-pass-manager 2>&1 | FileCheck %s --implicit-check-not=PGOInstrumentation
+
+; CHECK: Running pass: PGOInstrumentationUse
+
+target triple = "x86_64-apple-darwin"
+target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+
+define void @_start() {
+entry:
+  ret void
+}

lld/test/lit.cfg.py

 tool_patterns = [
     "llc",
     "llvm-as",
     "llvm-mc",
     "llvm-nm",
     "llvm-objdump",
     "llvm-otool",
     "llvm-pdbutil",
+    "llvm-profdata",
     "llvm-dwarfdump",
     "llvm-readelf",
     "llvm-readobj",
     "obj2yaml",
     "yaml2obj",
     "opt",
     "llvm-dis",
 ]