diff --git a/js/src/gc/GCRuntime.h b/js/src/gc/GCRuntime.h
index dff65809e4..00041e3348 100644
--- a/js/src/gc/GCRuntime.h
+++ b/js/src/gc/GCRuntime.h
@@ -1528,7 +1528,36 @@ class GCRuntime
      * During incremental sweeping, this field temporarily holds the arenas of
      * the current AllocKind being swept in order of increasing free space.
      */
-    SortedArenaList incrementalSweepList;
+    ActiveThreadData<SortedArenaList> incrementalSweepList;
+
+  private:
+    ActiveThreadData<Nursery> nursery_;
+    ActiveThreadData<gc::StoreBuffer> storeBuffer_;
+  public:
+    Nursery& nursery() { return nursery_.ref(); }
+    gc::StoreBuffer& storeBuffer() { return storeBuffer_.ref(); }
+
+    // Free LIFO blocks are transferred to this allocator before being freed
+    // after minor GC.
+    ActiveThreadData<LifoAlloc> blocksToFreeAfterMinorGC;
+
+    const void* addressOfNurseryPosition() {
+        return nursery_.refNoCheck().addressOfPosition();
+    }
+    const void* addressOfNurseryCurrentEnd() {
+        return nursery_.refNoCheck().addressOfCurrentEnd();
+    }
+
+    const void* addressOfStringNurseryCurrentEnd() {
+        return nursery_.refNoCheck().addressOfCurrentStringEnd();
+    }
+
+    void minorGC(JS::gcreason::Reason reason,
+                 gcstats::Phase phase = gcstats::PHASE_MINOR_GC) JS_HAZ_GC_CALL;
+    void evictNursery(JS::gcreason::Reason reason = JS::gcreason::EVICT_NURSERY) {
+        minorGC(reason, gcstats::PHASE_EVICT_NURSERY);
+    }
+    void freeAllLifoBlocksAfterMinorGC(LifoAlloc* lifo);
 
     friend class js::GCHelperState;
     friend class MarkingValidator;
diff --git a/js/src/gc/Nursery.cpp b/js/src/gc/Nursery.cpp
index bdde70a261..3ae4b1c516 100644
--- a/js/src/gc/Nursery.cpp
+++ b/js/src/gc/Nursery.cpp
@@ -120,6 +120,7 @@ js::Nursery::Nursery(JSRuntime* rt)
   , currentStartChunk_(0)
   , currentStartPosition_(0)
   , currentEnd_(0)
+  , currentStringEnd_(0)
   , currentChunk_(0)
   , maxChunkCount_(0)
   , chunkCountLimit_(0)
@@ -240,6 +241,8 @@ js::Nursery::disable()
 
     currentEnd_ = 0;
 
+    position_ = 0;
+    currentStringEnd_ = 0;
     runtime()->gc.storeBuffer().disable();
 }
 
@@ -248,6 +251,7 @@ js::Nursery::enableStrings()
 {
     MOZ_ASSERT(isEmpty());
     canAllocateStrings_ = true;
+    currentStringEnd_ = currentEnd_;
 }
 
 void
@@ -255,6 +259,7 @@ js::Nursery::disableStrings()
 {
     MOZ_ASSERT(isEmpty());
     canAllocateStrings_ = false;
+    currentStringEnd_ = 0;
 }
 
 bool
@@ -1002,6 +1007,8 @@ js::Nursery::setCurrentChunk(unsigned chunkno)
     currentChunk_ = chunkno;
     position_ = chunk(chunkno).start();
     currentEnd_ = chunk(chunkno).end();
+    if (canAllocateStrings_)
+        currentStringEnd_ = currentEnd_;
     chunk(chunkno).poisonAndInit(runtime(), JS_FRESH_NURSERY_PATTERN);
 }
 
diff --git a/js/src/gc/Nursery.h b/js/src/gc/Nursery.h
index 67c2fed982..0dca66e87d 100644
--- a/js/src/gc/Nursery.h
+++ b/js/src/gc/Nursery.h
@@ -316,6 +316,7 @@ class Nursery
 
     void* addressOfCurrentEnd() const { return (void*)&currentEnd_; }
     void* addressOfPosition() const { return (void*)&position_; }
+    void* addressOfCurrentStringEnd() const { return (void*)&currentStringEnd_; }
 
     void requestMinorGC(JS::gcreason::Reason reason) const;
 
@@ -357,6 +358,12 @@ class Nursery
     /* Pointer to the last byte of space in the current chunk. */
     uintptr_t currentEnd_;
 
+    /*
+     * Pointer to the last byte of space in the current chunk, or nullptr if we
+     * are not allocating strings in the nursery.
+     */
+    uintptr_t currentStringEnd_;
+
     /* The index of the chunk that is currently being allocated from. */
     unsigned currentChunk_;
 
diff --git a/js/src/jit/CompileWrappers.cpp b/js/src/jit/CompileWrappers.cpp
index 1db0122a49..3fa406274b 100644
--- a/js/src/jit/CompileWrappers.cpp
+++ b/js/src/jit/CompileWrappers.cpp
@@ -217,6 +217,45 @@ CompileZone::addressOfFreeList(gc::AllocKind allocKind)
     return zone()->arenas.addressOfFreeList(allocKind);
 }
 
+const void*
+CompileZone::addressOfNurseryPosition()
+{
+    return zone()->runtimeFromAnyThread()->gc.addressOfNurseryPosition();
+}
+
+const void*
+CompileZone::addressOfStringNurseryPosition()
+{
+    // Objects and strings share a nursery, for now at least.
+    return zone()->runtimeFromAnyThread()->gc.addressOfNurseryPosition();
+}
+
+const void*
+CompileZone::addressOfNurseryCurrentEnd()
+{
+    return zone()->runtimeFromAnyThread()->gc.addressOfNurseryCurrentEnd();
+}
+
+const void*
+CompileZone::addressOfStringNurseryCurrentEnd()
+{
+    return zone()->runtimeFromAnyThread()->gc.addressOfStringNurseryCurrentEnd();
+}
+
+bool
+CompileZone::nurseryExists()
+{
+    MOZ_ASSERT(CurrentThreadCanAccessZone(zone()));
+    return zone()->group()->nursery().exists();
+}
+
+void
+CompileZone::setMinorGCShouldCancelIonCompilations()
+{
+    MOZ_ASSERT(CurrentThreadCanAccessZone(zone()));
+    zone()->group()->storeBuffer().setShouldCancelIonCompilations();
+}
+
 JSCompartment*
 CompileCompartment::compartment()
 {
diff --git a/js/src/jit/CompileWrappers.h b/js/src/jit/CompileWrappers.h
index 618735627b..4854b87491 100644
--- a/js/src/jit/CompileWrappers.h
+++ b/js/src/jit/CompileWrappers.h
@@ -93,6 +93,11 @@ class CompileZone
     static CompileZone* get(Zone* zone);
 
     const void* addressOfNeedsIncrementalBarrier();
+    const void* addressOfFreeList(gc::AllocKind allocKind);
+    const void* addressOfNurseryPosition();
+    const void* addressOfStringNurseryPosition();
+    const void* addressOfNurseryCurrentEnd();
+    const void* addressOfStringNurseryCurrentEnd();
 
     const void* addressOfFreeList(gc::AllocKind allocKind);
 };
diff --git a/js/src/jit/MacroAssembler.cpp b/js/src/jit/MacroAssembler.cpp
index b1510109f4..22f8ca8f8b 100644
--- a/js/src/jit/MacroAssembler.cpp
+++ b/js/src/jit/MacroAssembler.cpp
@@ -887,8 +887,8 @@ MOZ_ASSERT(IsNurseryAllocable(allocKind));
     // very close to each other. In practice, the zone will probably be close
     // (within 32 bits) as well. If so, use relative offsets between them, to
     // avoid multiple 64-bit immediate loads.
-    auto nurseryPosAddr = intptr_t(zone->addressOfNurseryPosition());
-    auto nurseryEndAddr = intptr_t(zone->addressOfNurseryCurrentEnd());
+    auto nurseryPosAddr = intptr_t(zone->addressOfStringNurseryPosition());
+    auto nurseryEndAddr = intptr_t(zone->addressOfStringNurseryCurrentEnd());
     auto zoneAddr = intptr_t(zone);
 
     intptr_t maxOffset = std::max(std::abs(nurseryPosAddr - zoneAddr),