From 67c1214e3331d449f7b32a333a7055034d4805cb Mon Sep 17 00:00:00 2001
From: Jon Coppeard <jcoppeard@mozilla.com>
Date: Tue, 6 Oct 2015 14:50:49 +0100
Subject: [PATCH] Bug 1211100 - Add Vector::infallibleEmplaceBack and use it in
 JSScript::initScriptCounts() r=nbp

---
 js/src/jsscript.cpp | 2 +-
 mfbt/Vector.h       | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/js/src/jsscript.cpp b/js/src/jsscript.cpp
index f91f08d1a66..3c8d26b889f 100644
--- a/js/src/jsscript.cpp
+++ b/js/src/jsscript.cpp
@@ -1334,7 +1334,7 @@ JSScript::initScriptCounts(JSContext* cx)
         return false;
 
     for (size_t i = 0; i < jumpTargets.length(); i++)
-        MOZ_ALWAYS_TRUE(base.emplaceBack(pcToOffset(jumpTargets[i])));
+        base.infallibleEmplaceBack(pcToOffset(jumpTargets[i]));
 
     // Create compartment's scriptCountsMap if necessary.
     ScriptCountsMap* map = compartment()->scriptCountsMap;
diff --git a/mfbt/Vector.h b/mfbt/Vector.h
index 7f507ef5c3f..d18bfa70bd5 100644
--- a/mfbt/Vector.h
+++ b/mfbt/Vector.h
@@ -603,6 +603,12 @@ public:
   {
     internalAppend(aBegin, aLength);
   }
+  template<typename... Args>
+  void infallibleEmplaceBack(Args&&... aArgs)
+  {
+    infallibleGrowByUninitialized(1);
+    new (&back()) T(Forward<Args>(aArgs)...);
+  }
 
   void popBack();