Bug 1884378 - Expose Profiler's NativeStack structure r=canaltinova,profiler-reviewers

Differential Revision: https://phabricator.services.mozilla.com/D207732

tools/profiler/core/platform.cpp

@@ -41,6 +41,7 @@
 #include "ProfilerCPUFreq.h"
 #include "ProfilerIOInterposeObserver.h"
 #include "ProfilerParent.h"
+#include "ProfilerNativeStack.h"
 #include "ProfilerRustBindings.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/Maybe.h"
@@ -2027,18 +2028,6 @@ class Registers {
 #endif
 };
 
-// Setting MAX_NATIVE_FRAMES too high risks the unwinder wasting a lot of time
-// looping on corrupted stacks.
-static const size_t MAX_NATIVE_FRAMES = 1024;
-
-struct NativeStack {
-  void* mPCs[MAX_NATIVE_FRAMES];
-  void* mSPs[MAX_NATIVE_FRAMES];
-  size_t mCount;  // Number of frames filled.
-
-  NativeStack() : mPCs(), mSPs(), mCount(0) {}
-};
-
 Atomic<bool> WALKING_JS_STACK(false);
 
 struct AutoWalkJSStack {
@@ -2881,7 +2870,7 @@ static inline void DoSharedSample(
       aJsFrames ? ExtractJsFrames(aIsSynchronous, aThreadData, aRegs, collector,
                                   aJsFrames, stackWalkControlIfSupported)
                 : 0;
-  NativeStack nativeStack;
+  NativeStack nativeStack{.mCount = 0};
 #if defined(HAVE_NATIVE_UNWIND)
   if (captureNative) {
     DoNativeBacktrace(aThreadData, aRegs, nativeStack,
@@ -7657,7 +7646,7 @@ static void profiler_suspend_and_sample_thread(
   }
 
   // Allocate the space for the native stack
-  NativeStack nativeStack;
+  NativeStack nativeStack{.mCount = 0};
 
   auto collectStack = [&](const Registers& aRegs, const TimeStamp& aNow) {
     // The target thread is now suspended. Collect a native backtrace,

tools/profiler/moz.build

@@ -176,6 +176,7 @@ EXPORTS += [
     "public/ProfileAdditionalInformation.h",
     "public/ProfilerBindings.h",
     "public/ProfilerControl.h",
+    "public/ProfilerNativeStack.h",
     "public/ProfilerParent.h",
     "public/ProfilerRustBindings.h",
     "public/shared-libraries.h",

tools/profiler/public/ProfilerNativeStack.h

@@ -0,0 +1,23 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ProfilerNativeStack_h
+#define ProfilerNativeStack_h
+
+#include <stddef.h>
+
+// Setting MAX_NATIVE_FRAMES too high risks the unwinder wasting a lot of time
+// looping on corrupted stacks.
+
+static const size_t MAX_NATIVE_FRAMES = 1024;
+
+struct NativeStack {
+  void* mPCs[MAX_NATIVE_FRAMES];
+  void* mSPs[MAX_NATIVE_FRAMES];
+  size_t mCount;  // Number of frames filled.
+};
+
+#endif  // ProfilerNativeStack_h