[write-barrier] Generalise write-barrier native counter.

We would only increment write barrier counters from the the MacroAssembler's
RecordWrite method which is only used in limited cases.  Instead, we should
increment it inside the RecordWrite stub, this way we catch all uses, including
WASM.

Also, we had a static counter aimed at telling us how many barriers exist in
generated code, as opposed to how many are executed. This counter was not
functional since the compiler isn't aware of counters at the moment. Let's just
remove it to avoid confusion.

Change-Id: I6b173ab858c8984ef03ede225afdc999ba82b5c9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1524483Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
Cr-Commit-Position: refs/heads/master@{#60673}

src/arm/macro-assembler-arm.cc

@@ -802,14 +802,6 @@ void MacroAssembler::RecordWrite(Register object, Register address,
 
   bind(&done);
 
-  // Count number of write barriers in generated code.
-  isolate()->counters()->write_barriers_static()->Increment();
-  {
-    UseScratchRegisterScope temps(this);
-    IncrementCounter(isolate()->counters()->write_barriers_dynamic(), 1,
-                     temps.Acquire(), value);
-  }
-
   // Clobber clobbered registers when running with the debug-code flag
   // turned on to provoke errors.
   if (emit_debug_code()) {

src/arm64/macro-assembler-arm64.cc

@@ -3159,11 +3159,6 @@ void MacroAssembler::RecordWrite(Register object, Register address,
 
   Bind(&done);
 
-  // Count number of write barriers in generated code.
-  isolate()->counters()->write_barriers_static()->Increment();
-  IncrementCounter(isolate()->counters()->write_barriers_dynamic(), 1, address,
-                   value);
-
   // Clobber clobbered registers when running with the debug-code flag
   // turned on to provoke errors.
   if (emit_debug_code()) {

src/builtins/builtins-internal-gen.cc

@@ -6,6 +6,7 @@
 #include "src/builtins/builtins-utils-gen.h"
 #include "src/builtins/builtins.h"
 #include "src/code-stub-assembler.h"
+#include "src/counters.h"
 #include "src/heap/heap-inl.h"  // crbug.com/v8/8499
 #include "src/ic/accessor-assembler.h"
 #include "src/ic/keyed-store-generic.h"
@@ -446,6 +447,7 @@ TF_BUILTIN(RecordWrite, RecordWriteCodeStubAssembler) {
   }
 
   BIND(&exit);
+  IncrementCounter(isolate()->counters()->write_barriers(), 1);
   Return(TrueConstant());
 }
 
@@ -465,6 +467,7 @@ TF_BUILTIN(EphemeronKeyBarrier, RecordWriteCodeStubAssembler) {
       fp_mode, &exit);
 
   BIND(&exit);
+  IncrementCounter(isolate()->counters()->write_barriers(), 1);
   Return(TrueConstant());
 }
 

src/counters-definitions.h

@@ -302,10 +302,6 @@ namespace internal {
   SC(soft_deopts_requested, V8.SoftDeoptsRequested)                            \
   SC(soft_deopts_inserted, V8.SoftDeoptsInserted)                              \
   SC(soft_deopts_executed, V8.SoftDeoptsExecuted)                              \
-  /* Number of write barriers in generated code. */                            \
-  /* TODO: This isn't functional at the moment, we should teach the */         \
-  /* compiler about this counter.  */                                          \
-  SC(write_barriers_static, V8.WriteBarriersStatic)                            \
   SC(new_space_bytes_available, V8.MemoryNewSpaceBytesAvailable)               \
   SC(new_space_bytes_committed, V8.MemoryNewSpaceBytesCommitted)               \
   SC(new_space_bytes_used, V8.MemoryNewSpaceBytesUsed)                         \
@@ -337,7 +333,7 @@ namespace internal {
 // a separate list to be able to relocate them.
 #define STATS_COUNTER_NATIVE_CODE_LIST(SC)                         \
   /* Number of write barriers executed at runtime. */              \
-  SC(write_barriers_dynamic, V8.WriteBarriersDynamic)              \
+  SC(write_barriers, V8.WriteBarriers)                             \
   SC(constructed_objects, V8.ConstructedObjects)                   \
   SC(fast_new_closure_total, V8.FastNewClosureTotal)               \
   SC(regexp_entry_native, V8.RegExpEntryNative)                    \

src/ia32/macro-assembler-ia32.cc

@@ -513,10 +513,6 @@ void MacroAssembler::RecordWrite(Register object, Register address,
 
   bind(&done);
 
-  // Count number of write barriers in generated code.
-  isolate()->counters()->write_barriers_static()->Increment();
-  IncrementCounter(isolate()->counters()->write_barriers_dynamic(), 1, value);
-
   // Clobber clobbered registers when running with the debug-code flag
   // turned on to provoke errors.
   if (emit_debug_code()) {

src/mips/macro-assembler-mips.cc

@@ -361,15 +361,6 @@ void MacroAssembler::RecordWrite(Register object, Register address,
 
   bind(&done);
 
-  {
-    // Count number of write barriers in generated code.
-    isolate()->counters()->write_barriers_static()->Increment();
-    UseScratchRegisterScope temps(this);
-    Register scratch = temps.Acquire();
-    IncrementCounter(isolate()->counters()->write_barriers_dynamic(), 1,
-                     scratch, value);
-  }
-
   // Clobber clobbered registers when running with the debug-code flag
   // turned on to provoke errors.
   if (emit_debug_code()) {

src/mips64/macro-assembler-mips64.cc

@@ -359,15 +359,6 @@ void MacroAssembler::RecordWrite(Register object, Register address,
 
   bind(&done);
 
-  {
-    // Count number of write barriers in generated code.
-    UseScratchRegisterScope temps(this);
-    Register scratch = temps.Acquire();
-    isolate()->counters()->write_barriers_static()->Increment();
-    IncrementCounter(isolate()->counters()->write_barriers_dynamic(), 1,
-                     scratch, value);
-  }
-
   // Clobber clobbered registers when running with the debug-code flag
   // turned on to provoke errors.
   if (emit_debug_code()) {

src/ppc/macro-assembler-ppc.cc

@@ -591,11 +591,6 @@ void MacroAssembler::RecordWrite(Register object, Register address,
 
   bind(&done);
 
-  // Count number of write barriers in generated code.
-  isolate()->counters()->write_barriers_static()->Increment();
-  IncrementCounter(isolate()->counters()->write_barriers_dynamic(), 1, ip,
-                   value);
-
   // Clobber clobbered registers when running with the debug-code flag
   // turned on to provoke errors.
   if (emit_debug_code()) {

src/s390/macro-assembler-s390.cc

@@ -605,11 +605,6 @@ void MacroAssembler::RecordWrite(Register object, Register address,
 
   bind(&done);
 
-  // Count number of write barriers in generated code.
-  isolate()->counters()->write_barriers_static()->Increment();
-  IncrementCounter(isolate()->counters()->write_barriers_dynamic(), 1, ip,
-                   value);
-
   // Clobber clobbered registers when running with the debug-code flag
   // turned on to provoke errors.
   if (emit_debug_code()) {

src/x64/macro-assembler-x64.cc

@@ -516,10 +516,6 @@ void MacroAssembler::RecordWrite(Register object, Register address,
 
   bind(&done);
 
-  // Count number of write barriers in generated code.
-  isolate()->counters()->write_barriers_static()->Increment();
-  IncrementCounter(isolate()->counters()->write_barriers_dynamic(), 1);
-
   // Clobber clobbered registers when running with the debug-code flag
   // turned on to provoke errors.
   if (emit_debug_code()) {

test/unittests/counters-unittest.cc

@@ -821,5 +821,17 @@ TEST_F(SnapshotNativeCounterTest, SubStringNative) {
   PrintAll();
 }
 
+TEST_F(SnapshotNativeCounterTest, WriteBarrier) {
+  RunJS("let o = {a: 42};");
+
+  if (SupportsNativeCounters()) {
+    EXPECT_NE(0, write_barriers());
+  } else {
+    EXPECT_EQ(0, write_barriers());
+  }
+
+  PrintAll();
+}
+
 }  // namespace internal
 }  // namespace v8