From a7d96f6225d5cfb8d76036a15ada4add1fad881c Mon Sep 17 00:00:00 2001
From: Ehsan Akhgari <ehsan@mozilla.com>
Date: Wed, 18 Dec 2013 15:03:11 -0500
Subject: [PATCH] Bug 950856 - Fail the build if you attempt to use
 NS_StackWalk on Windows where it won't work; r=froydnj,BenWa

---
 xpcom/base/moz.build             | 16 +++++++++++++++-
 xpcom/base/nsTraceRefcntImpl.cpp | 10 ++++++++++
 xpcom/build/LateWriteChecks.cpp  |  6 ++++++
 xpcom/build/moz.build            |  3 +++
 4 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/xpcom/base/moz.build b/xpcom/base/moz.build
index fa05e8daa12..7768bc96dae 100644
--- a/xpcom/base/moz.build
+++ b/xpcom/base/moz.build
@@ -110,7 +110,6 @@ UNIFIED_SOURCES += [
     'nsMemoryReporterManager.cpp',
     'nsMessageLoop.cpp',
     'nsSecurityConsoleMessage.cpp',
-    'nsStackWalk.cpp',
     'nsSystemInfo.cpp',
     'nsTraceRefcntImpl.cpp',
     'nsUUIDGenerator.cpp',
@@ -118,6 +117,18 @@ UNIFIED_SOURCES += [
     'VisualEventTracer.cpp',
 ]
 
+# On Windows, NS_StackWalk will only work correctly if we have frame pointers available.
+# That will only be true for non-optimized builds, and for optimized builds with
+# --enable-profiling in the .mozconfig (which is turned on in Nightly by default.)
+# We exclude this file from other build configurations so that if somebody adds a
+# new usage of NS_StackWalk it will cause a link error, which is better than having
+# NS_StackWalk silently return garbage at runtime.
+if CONFIG['OS_TARGET'] != 'WINNT' or \
+   (not CONFIG['MOZ_OPTIMIZE'] or CONFIG['MOZ_PROFILING'] or CONFIG['MOZ_DEBUG']):
+    UNIFIED_SOURCES += [
+        'nsStackWalk.cpp',
+    ]
+
 if CONFIG['OS_ARCH'] == 'Linux':
     SOURCES += [
         'SystemMemoryReporter.cpp',
@@ -141,3 +152,6 @@ MSVC_ENABLE_PGO = True
 include('/ipc/chromium/chromium-config.mozbuild')
 
 FINAL_LIBRARY = 'xpcom_core'
+
+if CONFIG['MOZ_OPTIMIZE']:
+    DEFINES['MOZ_OPTIMIZE'] = True
diff --git a/xpcom/base/nsTraceRefcntImpl.cpp b/xpcom/base/nsTraceRefcntImpl.cpp
index 3ecfab2a79e..025bb7019d4 100644
--- a/xpcom/base/nsTraceRefcntImpl.cpp
+++ b/xpcom/base/nsTraceRefcntImpl.cpp
@@ -60,6 +60,10 @@ NS_MeanAndStdDev(double n, double sumOfValues, double sumOfSquaredValues,
 
 ////////////////////////////////////////////////////////////////////////////////
 
+#if !defined(XP_WIN) || (!defined(MOZ_OPTIMIZE) || defined(MOZ_PROFILING) || defined(DEBUG))
+#define STACKWALKING_AVAILABLE
+#endif
+
 #define NS_IMPL_REFCNT_LOGGING
 
 #ifdef NS_IMPL_REFCNT_LOGGING
@@ -836,6 +840,7 @@ static void InitTraceLog(void)
 
 extern "C" {
 
+#ifdef STACKWALKING_AVAILABLE
 static void PrintStackFrame(void *aPC, void *aSP, void *aClosure)
 {
   FILE *stream = (FILE*)aClosure;
@@ -846,14 +851,17 @@ static void PrintStackFrame(void *aPC, void *aSP, void *aClosure)
   NS_FormatCodeAddressDetails(aPC, &details, buf, sizeof(buf));
   fputs(buf, stream);
 }
+#endif
 
 }
 
 void
 nsTraceRefcntImpl::WalkTheStack(FILE* aStream)
 {
+#ifdef STACKWALKING_AVAILABLE
   NS_StackWalk(PrintStackFrame, /* skipFrames */ 2, /* maxFrames */ 0, aStream,
                0, nullptr);
+#endif
 }
 
 //----------------------------------------------------------------------
@@ -895,7 +903,9 @@ EXPORT_XPCOM_API(void)
 NS_LogInit()
 {
   // FIXME: This is called multiple times, we should probably not allow that.
+#ifdef STACKWALKING_AVAILABLE
   StackWalkInitCriticalAddress();
+#endif
 #ifdef NS_IMPL_REFCNT_LOGGING
   if (++gInitCount)
     nsTraceRefcntImpl::SetActivityIsLegal(true);
diff --git a/xpcom/build/LateWriteChecks.cpp b/xpcom/build/LateWriteChecks.cpp
index 5d244772dbd..891998314c3 100644
--- a/xpcom/build/LateWriteChecks.cpp
+++ b/xpcom/build/LateWriteChecks.cpp
@@ -34,6 +34,10 @@
 
 #include "LateWriteChecks.h"
 
+#if !defined(XP_WIN) || (!defined(MOZ_OPTIMIZE) || defined(MOZ_PROFILING) || defined(DEBUG))
+#define OBSERVE_LATE_WRITES
+#endif
+
 using namespace mozilla;
 
 /*************************** Auxiliary Declarations ***************************/
@@ -106,6 +110,7 @@ private:
 
 void LateWriteObserver::Observe(IOInterposeObserver::Observation& aOb)
 {
+#ifdef OBSERVE_LATE_WRITES
   // Crash if that is the shutdown check mode
   if (gShutdownChecks == SCM_CRASH) {
     MOZ_CRASH();
@@ -201,6 +206,7 @@ void LateWriteObserver::Observe(IOInterposeObserver::Observation& aOb)
   }
   PR_Delete(finalName.get());
   PR_Rename(name, finalName.get());
+#endif
 }
 
 /******************************* Setup/Teardown *******************************/
diff --git a/xpcom/build/moz.build b/xpcom/build/moz.build
index c3885269a07..a268042be27 100644
--- a/xpcom/build/moz.build
+++ b/xpcom/build/moz.build
@@ -75,3 +75,6 @@ DEFINES['OMNIJAR_NAME'] = CONFIG['OMNIJAR_NAME']
 
 if CONFIG['TARGET_XPCOM_ABI']:
     DEFINES['TARGET_XPCOM_ABI'] = '"%s"' % CONFIG['TARGET_XPCOM_ABI']
+
+if CONFIG['MOZ_OPTIMIZE']:
+    DEFINES['MOZ_OPTIMIZE'] = True