Rename rewriter stats

Hopefully this makes it more clear which stats are subsets of others,
and which ones should add up to other ones.

ex it was easy to think that "rewriter_attempts" succeeded as long
as "rewriter_aborts" didn't get incremented, but it could also not
have gotten started, etc.

Here's an example of the new stats:
ic_attempts: 1724625
ic_attempts_nopatch: 1306007
ic_attempts_skipped: 404969
ic_attempts_skipped_megamorphic: 85558
ic_attempts_successful: 13649
ic_rewrites: 13649
ic_rewrites_aborted: 3248
ic_rewrites_aborted_assemblyfail: 65
ic_rewrites_committed: 10401

minibenchmarks/django-template.py

+import os
+import sys
+sys.path.append(os.path.join(os.path.dirname(__file__), "../test/integration/django"))
+
 from django.template.base import Origin, Template, Context, TemplateDoesNotExist
 from django.conf import settings
 from django.apps import apps

src/asm_writing/icinfo.cpp

@@ -290,6 +290,10 @@ bool ICInfo::shouldAttempt() {
         retry_in--;
         return false;
     }
-    return times_rewritten < MEGAMORPHIC_THRESHOLD;
+    return !isMegamorphic();
+}
+
+bool ICInfo::isMegamorphic() {
+    return times_rewritten >= MEGAMORPHIC_THRESHOLD;
 }
 }

src/asm_writing/icinfo.h

@@ -120,6 +120,7 @@ public:
     void clear(ICSlotInfo* entry);
 
     bool shouldAttempt();
+    bool isMegamorphic();
 
     friend class ICSlotRewrite;
 };

src/asm_writing/rewriter.cpp

@@ -746,8 +746,8 @@ void Rewriter::abort() {
     finished = true;
     rewrite->abort();
 
-    static StatCounter rewriter_aborts("rewriter_aborts");
-    rewriter_aborts.log();
+    static StatCounter ic_rewrites_aborted("ic_rewrites_aborted");
+    ic_rewrites_aborted.log();
 }
 
 void RewriterVar::bumpUse() {
@@ -786,10 +786,10 @@ void Rewriter::commit() {
     assert(!finished);
     initPhaseEmitting();
 
-    static StatCounter rewriter_assemblyfail("rewriter_assemblyfail");
+    static StatCounter ic_rewrites_aborted_assemblyfail("ic_rewrites_aborted_assemblyfail");
 
     auto on_assemblyfail = [&]() {
-        rewriter_assemblyfail.log();
+        ic_rewrites_aborted_assemblyfail.log();
         this->abort();
     };
 
@@ -971,8 +971,8 @@ void Rewriter::commit() {
 
     finished = true;
 
-    static StatCounter rewriter_commits("rewriter_commits");
-    rewriter_commits.log();
+    static StatCounter ic_rewrites_committed("ic_rewrites_committed");
+    ic_rewrites_committed.log();
 }
 
 bool Rewriter::finishAssembly(ICSlotInfo* picked_slot, int continue_offset) {
@@ -1404,8 +1404,8 @@ Rewriter::Rewriter(ICSlotRewrite* rewrite, int num_args, const std::vector<int>&
         args.push_back(var);
     }
 
-    static StatCounter rewriter_starts("rewriter_starts");
-    rewriter_starts.log();
+    static StatCounter ic_rewrites_starts("ic_rewrites");
+    ic_rewrites_starts.log();
     static StatCounter rewriter_spillsavoided("rewriter_spillsavoided");
 
     // Calculate the list of live-ins based off the live-outs list,
@@ -1457,22 +1457,28 @@ Rewriter* Rewriter::createRewriter(void* rtn_addr, int num_args, const char* deb
         assert(!getICInfo(rtn_addr));
     }
 
-    static StatCounter rewriter_attempts("rewriter_attempts");
-    rewriter_attempts.log();
+    static StatCounter ic_attempts("ic_attempts");
+    static StatCounter ic_attempts_nopatch("ic_attempts_nopatch");
+    static StatCounter ic_attempts_skipped("ic_attempts_skipped");
+    static StatCounter ic_attempts_skipped_megamorphic("ic_attempts_skipped_megamorphic");
+    static StatCounter ic_attempts_started("ic_attempts_started");
 
-    static StatCounter rewriter_nopatch("rewriter_nopatch");
-    static StatCounter rewriter_skipped("rewriter_skipped");
+    ic_attempts.log();
 
     if (!ic) {
-        rewriter_nopatch.log();
+        ic_attempts_nopatch.log();
         return NULL;
     }
 
     if (!ic->shouldAttempt()) {
-        rewriter_skipped.log();
+        ic_attempts_skipped.log();
+
+        if (ic->isMegamorphic())
+            ic_attempts_skipped_megamorphic.log();
         return NULL;
     }
 
+    ic_attempts_started.log();
     return new Rewriter(ic->startRewrite(debug_name), num_args, ic->getLiveOuts());
 }