Fix samply profiling of SM JS code

libraries/source/spidermonkey/build.sh

@@ -6,7 +6,7 @@ cd "$(dirname "$0")"
 # This should match the version in config/milestone.txt
 FOLDER="mozjs-115.16.1"
 # If same-version changes are needed, increment this.
-LIB_VERSION="115.16.1+1"
+LIB_VERSION="115.16.1+2"
 LIB_NAME="mozjs115"
 
 echo "Building SpiderMonkey..."

libraries/source/spidermonkey/patches/FixProfiling.diff

@@ -0,0 +1,159 @@
+
+# HG changeset patch
+# User Markus Stange <mstange.moz@gmail.com>
+# Date 1706240334 0
+# Node ID a412d893c38f632f34b44a9c5b3fd8cc30bb87be
+# Parent  2a507cc2cf84980ce9f160d1ef80107ee7474ae4
+Bug 1876415 - Make timestamp formats consistent between Jitdump and the marker file. r=glandium
+
+On Linux and Android, both jitdump and the marker file will keep using
+`CLOCK_MONOTONIC` nanoseconds, as before.
+
+On macOS, both jitdump and the marker file will now be using
+`TimeStamp::RawMachAbsoluteTimeNanoseconds()` , i.e. "nanoseconds since
+mach_absolute_time origin".
+This value has the advantage that it is also relatively easy to obtain
+in other browser engines, because their internal timestamp value is stored
+in milliseconds or nanoseconds rather than in `mach_absolute_time` ticks.
+In the past, on macOS, Firefox was using `CLOCK_MONOTONIC` nanoseconds for
+jitdump and `TimeStamp::RawMachAbsoluteTimeValue()` for the marker file.
+This inconsistency is now fixed.
+I will update samply to change how it treats jitdump timestamps on macOS.
+There are no other consumers of jitdump files on macOS that I know of.
+
+On Windows, we will keep using raw QPC values for the marker file - this
+matches what's in the ETW events. Jitdump on Windows is mostly unused but
+I'm updating it to match.
+
+Furthermore, this fixes the order in mozglue/misc/moz.build to make sure
+we always use the TimeStamp_darwin implementation on Darwin (and not just
+due to a broken configure check, see bug 1681445), and it fixes the #ifdef
+in TimeStamp.h to match the Darwin check.
+
+Differential Revision: https://phabricator.services.mozilla.com/D199592
+
+diff --git a/js/src/jit/PerfSpewer.cpp b/js/src/jit/PerfSpewer.cpp
+--- a/js/src/jit/PerfSpewer.cpp
++++ b/js/src/jit/PerfSpewer.cpp
+@@ -118,19 +118,26 @@ static bool IsPerfProfiling() { return J
+ #endif
+ 
+ AutoLockPerfSpewer::AutoLockPerfSpewer() { PerfMutex.lock(); }
+ 
+ AutoLockPerfSpewer::~AutoLockPerfSpewer() { PerfMutex.unlock(); }
+ 
+ #ifdef JS_ION_PERF
+ static uint64_t GetMonotonicTimestamp() {
+-  struct timespec ts = {};
+-  clock_gettime(CLOCK_MONOTONIC, &ts);
+-  return ts.tv_sec * 1000000000 + ts.tv_nsec;
++  using mozilla::TimeStamp;
++#  ifdef XP_LINUX
++  return TimeStamp::Now().RawClockMonotonicNanosecondsSinceBoot();
++#  elif XP_WIN
++  return TimeStamp::Now().RawQueryPerformanceCounterValue().value();
++#  elif XP_MACOSX
++  return TimeStamp::Now().RawMachAbsoluteTimeNanoseconds();
++#  else
++  MOZ_CRASH("no timestamp");
++#  endif
+ }
+ 
+ // values are from /usr/include/elf.h
+ static uint32_t GetMachineEncoding() {
+ #  if defined(JS_CODEGEN_X86)
+   return 3;  // EM_386
+ #  elif defined(JS_CODEGEN_X64)
+   return 62;  // EM_X86_64
+diff --git a/mozglue/misc/TimeStamp.h b/mozglue/misc/TimeStamp.h
+--- a/mozglue/misc/TimeStamp.h
++++ b/mozglue/misc/TimeStamp.h
+@@ -469,18 +469,19 @@ class TimeStamp {
+   static MFBT_API void RecordProcessRestart();
+ 
+ #ifdef XP_LINUX
+   uint64_t RawClockMonotonicNanosecondsSinceBoot() {
+     return static_cast<uint64_t>(mValue);
+   }
+ #endif
+ 
+-#ifdef XP_MACOSX
+-  uint64_t RawMachAbsoluteTimeValue() { return static_cast<uint64_t>(mValue); }
++#ifdef XP_DARWIN
++  // Returns the number of nanoseconds since the mach_absolute_time origin.
++  MFBT_API uint64_t RawMachAbsoluteTimeNanoseconds() const;
+ #endif
+ 
+ #ifdef XP_WIN
+   Maybe<uint64_t> RawQueryPerformanceCounterValue() {
+     // mQPC is stored in `mt` i.e. QueryPerformanceCounter * 1000
+     // so divide out the 1000
+     return mValue.mHasQPC ? Some(mValue.mQPC / 1000ULL) : Nothing();
+   }
+diff --git a/mozglue/misc/TimeStamp_darwin.cpp b/mozglue/misc/TimeStamp_darwin.cpp
+--- a/mozglue/misc/TimeStamp_darwin.cpp
++++ b/mozglue/misc/TimeStamp_darwin.cpp
+@@ -131,26 +131,28 @@ void TimeStamp::Startup() {
+   // find the number of significant digits in sResolution, for the
+   // sake of ToSecondsSigDigits()
+   for (sResolutionSigDigs = 1; !(sResolutionSigDigs == sResolution ||
+                                  10 * sResolutionSigDigs > sResolution);
+        sResolutionSigDigs *= 10)
+     ;
+ 
+   gInitialized = true;
+-
+-  return;
+ }
+ 
+ void TimeStamp::Shutdown() {}
+ 
+ TimeStamp TimeStamp::Now(bool aHighResolution) {
+   return TimeStamp(ClockTime());
+ }
+ 
++uint64_t TimeStamp::RawMachAbsoluteTimeNanoseconds() const {
++  return static_cast<uint64_t>(double(mValue) * sNsPerTick);
++}
++
+ // Computes and returns the process uptime in microseconds.
+ // Returns 0 if an error was encountered.
+ uint64_t TimeStamp::ComputeProcessUptime() {
+   struct timeval tv;
+   int rv = gettimeofday(&tv, nullptr);
+ 
+   if (rv == -1) {
+     return 0;
+diff --git a/mozglue/misc/moz.build b/mozglue/misc/moz.build
+--- a/mozglue/misc/moz.build
++++ b/mozglue/misc/moz.build
+@@ -105,24 +105,24 @@ if CONFIG["OS_ARCH"] == "WINNT":
+ 
+     if not CONFIG["JS_STANDALONE"]:
+         SOURCES += [
+             "/ipc/mscom/COMWrappers.cpp",
+             "/ipc/mscom/ProcessRuntime.cpp",
+             "PreXULSkeletonUI.cpp",
+         ]
+ 
++elif CONFIG["OS_ARCH"] == "Darwin":
++    SOURCES += [
++        "TimeStamp_darwin.cpp",
++    ]
+ elif CONFIG["HAVE_CLOCK_MONOTONIC"]:
+     SOURCES += [
+         "TimeStamp_posix.cpp",
+     ]
+-elif CONFIG["OS_ARCH"] == "Darwin":
+-    SOURCES += [
+-        "TimeStamp_darwin.cpp",
+-    ]
+ elif CONFIG["COMPILE_ENVIRONMENT"]:
+     error("No TimeStamp implementation on this platform.  Build will not succeed")
+ 
+ if CONFIG["OS_ARCH"] == "WINNT":
+     SOURCES += [
+         "ConditionVariable_windows.cpp",
+         "Mutex_windows.cpp",
+         "RWLock_windows.cpp",
+

libraries/source/spidermonkey/patches/patch.sh

@@ -41,3 +41,8 @@ patch -p1 <"${PATCHES}"/FixClang19.diff
 # Fix build with Python >=3.12.8 and Python >=3.13.1
 # https://bugzilla.mozilla.org/show_bug.cgi?id=1935621
 patch -p1 <"${PATCHES}"/FixPython3.12.8.diff
+
+# Fix build for profiling with samply.
+# https://bugzilla.mozilla.org/show_bug.cgi?id=1876415
+# Fixed in ESR 128
+patch -p1 <"${PATCHES}"/FixProfiling.diff