Bug 1492121 - Run BaseProfiler's InitializeWin64ProfilerHooks once from either profiler - r=njn

Running identical (but separate) InitializeWin64ProfilerHooks in both profilers
confuses the DLL interceptor and the 2nd one crashes because of unexpected
opcodes introduced by the 1st one.
If MOZ_BASE_PROFILER is defined, Gecko Profiler will use that implementation of
InitializeWin64ProfilerHooks instead of its own; and that code also has a guard
so that it effectively only run once even if called from both profilers.

Differential Revision: https://phabricator.services.mozilla.com/D31931

--HG--
extra : moz-landing-system : lando

mozglue/baseprofiler/core/platform-win32.cpp

@@ -314,7 +314,15 @@ static PVOID WINAPI patched_LdrResolveDelayLoadedAPI(
                                        ThunkAddress, Flags);
 }
 
-void InitializeWin64ProfilerHooks() {
+MFBT_API void InitializeWin64ProfilerHooks() {
+  // This function could be called by both profilers, but we only want to run
+  // it once.
+  static bool ran = false;
+  if (ran) {
+    return;
+  }
+  ran = true;
+
   NtDllIntercept.Init("ntdll.dll");
   stub_LdrUnloadDll.Set(NtDllIntercept, "LdrUnloadDll", &patched_LdrUnloadDll);
   if (IsWin8OrLater()) {  // LdrResolveDelayLoadedAPI was introduced in Win8

tools/profiler/core/platform-win32.cpp

@@ -269,6 +269,10 @@ void Registers::SyncPopulate() {
 #endif
 
 #if defined(GP_PLAT_amd64_windows)
+
+#  ifndef MOZ_BASE_PROFILER
+// If MOZ_BASE_PROFILER is *not* #defined, we need to implement this here, as
+// the one in mozglue/baseprofiler will not even be built.
 static WindowsDllInterceptor NtDllIntercept;
 
 typedef NTSTATUS(NTAPI* LdrUnloadDll_func)(HMODULE module);
@@ -308,4 +312,18 @@ void InitializeWin64ProfilerHooks() {
                                       &patched_LdrResolveDelayLoadedAPI);
   }
 }
-#endif  // defined(GP_PLAT_amd64_windows)
+
+#  else  // ndef MOZ_BASE_PROFILER
+// If MOZ_BASE_PROFILER is #defined, we just use InitializeWin64ProfilerHooks
+// that it implements.
+
+namespace mozilla {
+namespace baseprofiler {
+MFBT_API void InitializeWin64ProfilerHooks();
+}  // namespace baseprofiler
+}  // namespace mozilla
+
+using mozilla::baseprofiler::InitializeWin64ProfilerHooks;
+
+#  endif  // ndef MOZ_BASE_PROFILER else
+#endif    // defined(GP_PLAT_amd64_windows)

tools/profiler/core/platform.cpp

@@ -59,6 +59,7 @@
 #include "mozilla/Tuple.h"
 #include "mozilla/UniquePtr.h"
 #include "mozilla/Vector.h"
+#include "BaseProfiler.h"
 #include "nsDirectoryServiceDefs.h"
 #include "nsDirectoryServiceUtils.h"
 #include "nsIHttpProtocolHandler.h"