[lld-macho] minimal TimeTrace support

[tschuett]

Summary

This is the minimal port from ELF. Any extension should easy from here

Test plan: ninja check-all-macho

[tschuett]

lld/MachO/Driver.cpp

783

I add this back in the next iteration.

[tschuett]

blank line

[thakis]

Nice!

lld/MachO/Driver.cpp

947

ELF has just "Link" here, no 2nd arg. Do we need the 2nd arg?

[tschuett]

lld/MachO/Driver.cpp

947

The ELF test checks for ExecuteLinker?!?

lld/MachO/Config.h

struct Configuration {
   bool headerPadMaxInstallNames = false;
   bool ltoNewPassManager = LLVM_ENABLE_NEW_PASS_MANAGER;
   bool markDeadStrippableDylib = false;
   bool printEachFile = false;
   bool printWhyLoad = false;
   bool searchDylibsFirst = false;
   bool saveTemps = false;
   bool adhocCodesign = false;
+  bool timeTraceEnabled = false;
   uint32_t headerPad;
   uint32_t dylibCompatibilityVersion = 0;
   uint32_t dylibCurrentVersion = 0;
+  uint32_t timeTraceGranularity;
+  std::string progName;
   llvm::StringRef installName;
   llvm::StringRef outputFile;
   llvm::StringRef ltoObjPath;
   bool demangle = false;
   llvm::MachO::Target target;
   PlatformInfo platformInfo;
   NamespaceKind namespaceKind = NamespaceKind::twolevel;
   UndefinedSymbolTreatment undefinedSymbolTreatment =

lld/MachO/Driver.cpp

 #include "llvm/Option/ArgList.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/TarWriter.h"
 #include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/TimeProfiler.h"
 #include "llvm/TextAPI/MachO/PackedVersion.h"
 
 #include <algorithm>
 
 using namespace llvm;
 using namespace llvm::MachO;
 using namespace llvm::object;
 using namespace llvm::opt;
bool macho::link(ArrayRef<const char *> argsArr, bool canExitEarly,
   lld::stderrOS = &stderrOS;
 
   errorHandler().cleanupCallback = []() { freeArena(); };
 
   errorHandler().logName = args::getFilenameWithoutExe(argsArr[0]);
   stderrOS.enable_colors(stderrOS.has_colors());
   // TODO: Set up error handler properly, e.g. the errorLimitExceededMsg
 
-
   MachOOptTable parser;
   InputArgList args = parser.parse(argsArr.slice(1));
 
   if (args.hasArg(OPT_help_hidden)) {
     parser.printHelp(argsArr[0], /*showHidden=*/true);
     return true;
   }
   if (args.hasArg(OPT_help)) {
message(StringRef("Library search paths:") +
                  ? "\n\t" + join(config->librarySearchPaths, "\n\t")
                  : ""));
     message(StringRef("Framework search paths:") +
             (config->frameworkSearchPaths.size()
                  ? "\n\t" + join(config->frameworkSearchPaths, "\n\t")
                  : ""));
   }
 
+  config->progName = argsArr[0];
+
+  config->timeTraceEnabled = args.hasArg(OPT_time_trace);
+
+  // Initialize time trace profiler.
+  if (config->timeTraceEnabled)
+    timeTraceProfilerInitialize(config->timeTraceGranularity, config->progName);
+
+  {
+    llvm::TimeTraceScope timeScope("Link", StringRef("ExecuteLinker"));
+
     initLLVM(); // must be run before any call to addFile()
 
     // This loop should be reserved for options whose exact ordering matters.
     // Other options should be handled via filtered() and/or getLastArg().
     for (const Arg *arg : args) {
       const Option &opt = arg->getOption();
       warnIfDeprecatedOption(opt);
       warnIfUnimplementedOption(opt);
 
       switch (opt.getID()) {
       case OPT_INPUT:
         addFile(arg->getValue(), false);
         break;
       case OPT_weak_library:
         if (auto *dylibFile =
                 dyn_cast_or_null<DylibFile>(addFile(arg->getValue(), false)))
           dylibFile->forceWeakImport = true;
         break;
       case OPT_filelist:
         addFileList(arg->getValue());
         break;
       case OPT_force_load:
         addFile(arg->getValue(), true);
         break;
       case OPT_l:
       case OPT_weak_l:
         addLibrary(arg->getValue(), opt.getID() == OPT_weak_l);
         break;
       case OPT_framework:
       case OPT_weak_framework:
         addFramework(arg->getValue(), opt.getID() == OPT_weak_framework);
         break;
       default:
         break;
       }
     }
 
     config->isPic = config->outputType == MH_DYLIB ||
                     config->outputType == MH_BUNDLE || isPie(args);
 
     // Now that all dylibs have been loaded, search for those that should be
     // re-exported.
     for (const Arg *arg : args.filtered(OPT_sub_library, OPT_sub_umbrella)) {
       config->hasReexports = true;
       StringRef searchName = arg->getValue();
       std::vector<StringRef> extensions;
       if (arg->getOption().getID() == OPT_sub_library)
         extensions = {".dylib", ".tbd"};
       else
         extensions = {".tbd"};
       if (!markReexport(searchName, extensions))
         error(arg->getSpelling() + " " + searchName +
               " does not match a supplied dylib");
     }
 
     // Parse LTO options.
     if (const Arg *arg = args.getLastArg(OPT_mcpu))
       parseClangOption(saver.save("-mcpu=" + StringRef(arg->getValue())),
                        arg->getSpelling());
 
     for (const Arg *arg : args.filtered(OPT_mllvm))
       parseClangOption(arg->getValue(), arg->getSpelling());
 
     compileBitcodeFiles();
     replaceCommonSymbols();
 
     StringRef orderFile = args.getLastArgValue(OPT_order_file);
     if (!orderFile.empty())
       parseOrderFile(orderFile);
 
     if (config->outputType == MH_EXECUTE && isa<Undefined>(config->entry)) {
       error("undefined symbol: " + toString(*config->entry));
       return false;
     }
     // FIXME: This prints symbols that are undefined both in input files and
     // via -u flag twice.
     for (const Symbol *undefined : config->explicitUndefineds) {
       if (isa<Undefined>(undefined)) {
         error("undefined symbol: " + toString(*undefined) +
               "\n>>> referenced by flag -u " + toString(*undefined));
         return false;
       }
     }
 
     createSyntheticSections();
     symtab->addDSOHandle(in.header);
 
     for (const Arg *arg : args.filtered(OPT_sectcreate)) {
       StringRef segName = arg->getValue(0);
       StringRef sectName = arg->getValue(1);
       StringRef fileName = arg->getValue(2);
       Optional<MemoryBufferRef> buffer = readFile(fileName);
       if (buffer)
         inputFiles.insert(make<OpaqueFile>(*buffer, segName, sectName));
     }
 
     // Initialize InputSections.
     for (const InputFile *file : inputFiles) {
       for (const SubsectionMap &map : file->subsections) {
         for (const auto &p : map) {
           InputSection *isec = p.second;
           inputSections.push_back(isec);
         }
       }
     }
 
     // Write to an output file.
     writeResult();
+  }
+
+  if (config->timeTraceEnabled) {
+    if (auto E = timeTraceProfilerWrite(
+            args.getLastArgValue(OPT_time_trace_file_eq).str(),
+            config->outputFile)) {
+      handleAllErrors(std::move(E),
+                      [&](const StringError &SE) { error(SE.getMessage()); });
+    }
+
+    timeTraceProfilerCleanup();
+  }
 
   if (canExitEarly)
     exitLld(errorCount() ? 1 : 0);
 
   return !errorCount();
 }

lld/MachO/Options.td

def version: Flag<["--"], "version">,
     HelpText<"Display the version number and exit">,
     Group<grp_lld>;
 def lto_legacy_pass_manager: Flag<["--"], "lto-legacy-pass-manager">,
     HelpText<"Use the legacy pass manager in LLVM">,
     Group<grp_lld>;
 def no_lto_legacy_pass_manager : Flag<["--"], "no-lto-legacy-pass-manager">,
     HelpText<"Use the new pass manager in LLVM">,
     Group<grp_lld>;
-
+def time_trace: Flag<["--"], "time-trace">, HelpText<"Record time trace">;
+def time_trace_granularity: Flag<["--"], "time-trace-granularity">,
+  HelpText<"Minimum time granularity (in microseconds) traced by time profiler">;
+def time_trace_file_eq: Flag<["--"], "time-trace-file=">, HelpText<"Specify time trace output file">;
 
 // 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/time-trace.s

+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64 %s -o %t.o
+
+# Test implicit trace file name
+# RUN: ld.lld --time-trace --time-trace-granularity=0 -o %t1.macho %t.o
+# RUN: cat %t1.macho.time-trace \
+# RUN:   | %python -c 'import json, sys; json.dump(json.loads(sys.stdin.read()), sys.stdout, sort_keys=True, indent=2)' \
+# RUN:   | FileCheck %s
+
+# Test specified trace file name
+# RUN: ld.lld --time-trace --time-trace-file=%t2.json --time-trace-granularity=0 -o %t2.macho %t.o
+# RUN: cat %t2.json \
+# RUN:   | %python -c 'import json, sys; json.dump(json.loads(sys.stdin.read()), sys.stdout, sort_keys=True, indent=2)' \
+# RUN:   | FileCheck %s
+
+# Test trace requested to stdout
+# RUN: ld.lld --time-trace --time-trace-file=- --time-trace-granularity=0 -o %t3.macho %t.o \
+# RUN:   | %python -c 'import json, sys; json.dump(json.loads(sys.stdin.read()), sys.stdout, sort_keys=True, indent=2)' \
+# RUN:   | FileCheck %s
+
+# CHECK:      "beginningOfTime": {{[0-9]{16},}}
+# CHECK-NEXT: "traceEvents": [
+
+# Check one event has correct fields
+# CHECK:      "dur":
+# CHECK-NEXT: "name":
+# CHECK-NEXT: "ph":
+# CHECK-NEXT: "pid":
+# CHECK-NEXT: "tid":
+# CHECK-NEXT: "ts":
+
+# Check there is an ExecuteLinker event
+# CHECK: "name": "ExecuteLinker"
+
+# Check process_name entry field
+# CHECK: "name": "ld.lld{{(.exe)?}}"
+# CHECK: "name": "process_name"
+# CHECK: "name": "thread_name"
+
+.globl _start
+_start:
+  ret