[builtins] Add embedded stats to --serialization-statistics

This adds the option to output statistics about the embedded blob.

On x64 release, the output is currently:

Total size:                         724064
Metadata size:                      6832
Instruction size:                   703427
Padding:                            13805
Embedded builtin count:             852
Instruction size (50th percentile): 222
Instruction size (75th percentile): 749
Instruction size (90th percentile): 1871
Instruction size (99th percentile): 9171

Total size is added to our Memory benchmark.

Drive-by: Fix startup / context regexps for Memory benchmark.

Bug: v8:6666, v8:7898
Change-Id: I90d4458877939d3b48593bd9dd3a33971fe78c44
Reviewed-on: https://chromium-review.googlesource.com/1126104
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54256}

src/snapshot/snapshot-common.cc

@@ -450,6 +450,8 @@ EmbeddedData EmbeddedData::FromIsolate(Isolate* isolate) {
   DCHECK_EQ(hash, d.CreateHash());
   DCHECK_EQ(hash, d.Hash());
 
+  if (FLAG_serialization_statistics) d.PrintStatistics();
+
   return d;
 }
 
@@ -488,6 +490,48 @@ uint32_t Snapshot::ExtractNumContexts(const v8::StartupData* data) {
   return num_contexts;
 }
 
+void EmbeddedData::PrintStatistics() const {
+  DCHECK(FLAG_serialization_statistics);
+
+  constexpr int kCount = Builtins::builtin_count;
+
+  int embedded_count = 0;
+  int instruction_size = 0;
+  int sizes[kCount];
+  for (int i = 0; i < kCount; i++) {
+    if (!Builtins::IsIsolateIndependent(i)) continue;
+    const int size = InstructionSizeOfBuiltin(i);
+    instruction_size += size;
+    sizes[embedded_count] = size;
+    embedded_count++;
+  }
+
+  // Sort for percentiles.
+  std::sort(&sizes[0], &sizes[embedded_count]);
+
+  const int k50th = embedded_count * 0.5;
+  const int k75th = embedded_count * 0.75;
+  const int k90th = embedded_count * 0.90;
+  const int k99th = embedded_count * 0.99;
+
+  const int metadata_size =
+      static_cast<int>(HashSize() + OffsetsSize() + LengthsSize());
+
+  PrintF("EmbeddedData:\n");
+  PrintF("  Total size:                         %d\n",
+         static_cast<int>(size()));
+  PrintF("  Metadata size:                      %d\n", metadata_size);
+  PrintF("  Instruction size:                   %d\n", instruction_size);
+  PrintF("  Padding:                            %d\n",
+         static_cast<int>(size() - metadata_size - instruction_size));
+  PrintF("  Embedded builtin count:             %d\n", embedded_count);
+  PrintF("  Instruction size (50th percentile): %d\n", sizes[k50th]);
+  PrintF("  Instruction size (75th percentile): %d\n", sizes[k75th]);
+  PrintF("  Instruction size (90th percentile): %d\n", sizes[k90th]);
+  PrintF("  Instruction size (99th percentile): %d\n", sizes[k99th]);
+  PrintF("\n");
+}
+
 uint32_t Snapshot::ExtractContextOffset(const v8::StartupData* data,
                                         uint32_t index) {
   // Extract the offset of the context at a given index from the StartupData,

src/snapshot/snapshot.h

@@ -139,6 +139,8 @@ class EmbeddedData final {
   }
   const uint8_t* RawData() const { return data_ + RawDataOffset(); }
 
+  void PrintStatistics() const;
+
   const uint8_t* data_;
   uint32_t size_;
 };

test/cctest/test-serialize.cc

@@ -3548,11 +3548,21 @@ UNINITIALIZED_TEST(ReinitializeHashSeedRehashable) {
   delete[] blob.data;
 }
 
-TEST(SerializationMemoryStats) {
+TEST(SerializationStats) {
   FLAG_profile_deserialization = true;
   FLAG_always_opt = false;
   v8::StartupData blob = CreateSnapshotDataBlob();
   delete[] blob.data;
+
+  // Track the embedded blob size as well.
+  {
+    int embedded_blob_size = 0;
+    if (FLAG_embedded_builtins) {
+      i::EmbeddedData d = i::EmbeddedData::FromBlob();
+      embedded_blob_size = static_cast<int>(d.size());
+    }
+    PrintF("Embedded blob is %d bytes\n", embedded_blob_size);
+  }
 }
 
 void CheckSFIsAreWeak(WeakFixedArray* sfis, Isolate* isolate) {

test/memory/Memory.json

@@ -1,11 +1,11 @@
 {
-  "owners": ["yangguo@chromium.org"],
+  "owners": ["yangguo@chromium.org", "jgruber@chromium.org"],
   "name": "Memory",
   "run_count": 5,
   "units": "bytes",
   "path" : ["."],
   "binary": "cctest",
-  "main": "test-serialize/SerializationMemoryStats",
+  "main": "test-serialize/SerializationStats",
   "tests": [
     {
       "name": "ReservedMemoryIsolate",
@@ -17,7 +17,7 @@
     },
     {
       "name": "SnapshotSizeStartup",
-      "results_regexp": "(\\d+) bytes for startup$"
+      "results_regexp": "(\\d+) bytes in \\d+ chunks for startup$"
     },
     {
       "name": "SnapshotSizeBuiltins",
@@ -25,7 +25,7 @@
     },
     {
       "name": "SnapshotSizeContext",
-      "results_regexp": "(\\d+) bytes for context #0$"
+      "results_regexp": "(\\d+) bytes in \\d+ chunks for context #0$"
     },
     {
       "name": "DeserializationTimeIsolate",
@@ -34,6 +34,10 @@
     {
       "name": "DeserializationTimeContext",
       "results_regexp": "\\[Deserializing context #0 \\(\\d+ bytes\\) took ([\\d.]+) ms\\]"
+    },
+    {
+      "name": "EmbeddedBuiltinsSize",
+      "results_regexp": "^Embedded blob is (\\d+) bytes$"
     }
   ]
 }