diff --git a/js/src/jit/Snapshots.cpp b/js/src/jit/Snapshots.cpp
index dd9cebf32f2d..92d73a1deafa 100644
--- a/js/src/jit/Snapshots.cpp
+++ b/js/src/jit/Snapshots.cpp
@@ -482,6 +482,14 @@ SnapshotReader::readSnapshotHeader()
     resumeAfter_ = !!(bits & (1 << BAILOUT_RESUME_SHIFT));
     framesRead_ = 0;
 
+#ifdef TRACK_SNAPSHOTS
+    pcOpcode_  = reader_.readUnsigned();
+    mirOpcode_ = reader_.readUnsigned();
+    mirId_     = reader_.readUnsigned();
+    lirOpcode_ = reader_.readUnsigned();
+    lirId_     = reader_.readUnsigned();
+#endif
+
     IonSpew(IonSpew_Snapshots, "Read snapshot header with frameCount %u, bailout kind %u (ra: %d)",
             frameCount_, bailoutKind_, resumeAfter_);
 }
@@ -494,13 +502,6 @@ SnapshotReader::readFrameHeader()
 
     pcOffset_ = reader_.readUnsigned();
     allocCount_ = reader_.readUnsigned();
-#ifdef TRACK_SNAPSHOTS
-    pcOpcode_  = reader_.readUnsigned();
-    mirOpcode_ = reader_.readUnsigned();
-    mirId_     = reader_.readUnsigned();
-    lirOpcode_ = reader_.readUnsigned();
-    lirId_     = reader_.readUnsigned();
-#endif
     IonSpew(IonSpew_Snapshots, "Read pc offset %u, nslots %u", pcOffset_, allocCount_);
 
     framesRead_++;
@@ -592,8 +593,8 @@ SnapshotWriter::startFrame(JSFunction *fun, JSScript *script, jsbytecode *pc, ui
 
 #ifdef TRACK_SNAPSHOTS
 void
-SnapshotWriter::trackFrame(uint32_t pcOpcode, uint32_t mirOpcode, uint32_t mirId,
-                                            uint32_t lirOpcode, uint32_t lirId)
+SnapshotWriter::trackSnapshot(uint32_t pcOpcode, uint32_t mirOpcode, uint32_t mirId,
+                              uint32_t lirOpcode, uint32_t lirId)
 {
     writer_.writeUnsigned(pcOpcode);
     writer_.writeUnsigned(mirOpcode);
diff --git a/js/src/jit/Snapshots.h b/js/src/jit/Snapshots.h
index 726e1458540a..78ce5c268b8a 100644
--- a/js/src/jit/Snapshots.h
+++ b/js/src/jit/Snapshots.h
@@ -326,11 +326,11 @@ class SnapshotWriter
     bool init();
 
     SnapshotOffset startSnapshot(uint32_t frameCount, BailoutKind kind, bool resumeAfter);
-    void startFrame(JSFunction *fun, JSScript *script, jsbytecode *pc, uint32_t exprStack);
 #ifdef TRACK_SNAPSHOTS
-    void trackFrame(uint32_t pcOpcode, uint32_t mirOpcode, uint32_t mirId,
-                    uint32_t lirOpcode, uint32_t lirId);
+    void trackSnapshot(uint32_t pcOpcode, uint32_t mirOpcode, uint32_t mirId,
+                       uint32_t lirOpcode, uint32_t lirId);
 #endif
+    void startFrame(JSFunction *fun, JSScript *script, jsbytecode *pc, uint32_t exprStack);
     void endFrame();
 
     bool add(const RValueAllocation &slot);
diff --git a/js/src/jit/shared/CodeGenerator-shared.cpp b/js/src/jit/shared/CodeGenerator-shared.cpp
index 7879ae279e68..869a2f733007 100644
--- a/js/src/jit/shared/CodeGenerator-shared.cpp
+++ b/js/src/jit/shared/CodeGenerator-shared.cpp
@@ -250,6 +250,26 @@ CodeGeneratorShared::encode(LSnapshot *snapshot)
     SnapshotOffset offset = snapshots_.startSnapshot(frameCount, snapshot->bailoutKind(),
                                                      resumeAfter);
 
+#ifdef TRACK_SNAPSHOTS
+    uint32_t pcOpcode = 0;
+    uint32_t lirOpcode = 0;
+    uint32_t lirId = 0;
+    uint32_t mirOpcode = 0;
+    uint32_t mirId = 0;
+
+    if (LInstruction *ins = instruction()) {
+        lirOpcode = ins->op();
+        lirId = ins->id();
+        if (ins->mirRaw()) {
+            mirOpcode = ins->mirRaw()->op();
+            mirId = ins->mirRaw()->id();
+            if (ins->mirRaw()->trackedPc())
+                pcOpcode = *ins->mirRaw()->trackedPc();
+        }
+    }
+    snapshots_.trackSnapshot(pcOpcode, mirOpcode, mirId, lirOpcode, lirId);
+#endif
+
     FlattenedMResumePointIter mirOperandIter(snapshot->mir());
     if (!mirOperandIter.init())
         return false;
@@ -305,28 +325,6 @@ CodeGeneratorShared::encode(LSnapshot *snapshot)
         }
 #endif
 
-#ifdef TRACK_SNAPSHOTS
-        LInstruction *ins = instruction();
-
-        uint32_t pcOpcode = 0;
-        uint32_t lirOpcode = 0;
-        uint32_t lirId = 0;
-        uint32_t mirOpcode = 0;
-        uint32_t mirId = 0;
-
-        if (ins) {
-            lirOpcode = ins->op();
-            lirId = ins->id();
-            if (ins->mirRaw()) {
-                mirOpcode = ins->mirRaw()->op();
-                mirId = ins->mirRaw()->id();
-                if (ins->mirRaw()->trackedPc())
-                    pcOpcode = *ins->mirRaw()->trackedPc();
-            }
-        }
-        snapshots_.trackFrame(pcOpcode, mirOpcode, mirId, lirOpcode, lirId);
-#endif
-
         if (!encodeAllocations(snapshot, mir, &startIndex))
             return false;
         snapshots_.endFrame();