Delta encode pc descriptors, and combine pc kind and try index into single field.

runtime/vm/object_test.cc

Index: runtime/vm/object_test.cc
diff --git a/runtime/vm/object_test.cc b/runtime/vm/object_test.cc
index 8dbbb529db8c22ca3b45522c40a93d7e6c6833f6..5e72ebfe4343a587f4d3948fe38b15115a0bb715 100644
--- a/runtime/vm/object_test.cc
+++ b/runtime/vm/object_test.cc
@@ -15,6 +15,7 @@
 #include "vm/simulator.h"
 #include "vm/symbols.h"
 #include "vm/unit_test.h"
+#include "vm/code_descriptors.h"
 
 namespace dart {
 
@@ -2865,16 +2866,18 @@ TEST_CASE(ExceptionHandlers) {
 
 
 TEST_CASE(PcDescriptors) {
-  const int kNumEntries = 6;
-  // Add PcDescriptors to the code.
+  DescriptorList* builder = new DescriptorList(0);
+
+  // kind, pc_offset, deopt_id, token_pos, try_index
+  builder->AddDescriptor(RawPcDescriptors::kOther, 10, 1, 20, 1);
+  builder->AddDescriptor(RawPcDescriptors::kDeopt, 20, 2, 30, 0);
+  builder->AddDescriptor(RawPcDescriptors::kOther, 30, 3, 40, 1);
+  builder->AddDescriptor(RawPcDescriptors::kOther, 10, 4, 40, 2);
+  builder->AddDescriptor(RawPcDescriptors::kOther, 10, 5, 80, 3);
+  builder->AddDescriptor(RawPcDescriptors::kOther, 80, 6, 150, 3);
+
   PcDescriptors& descriptors = PcDescriptors::Handle();
-  descriptors ^= PcDescriptors::New(kNumEntries, true);
-  descriptors.AddDescriptor(0, 10, RawPcDescriptors::kOther, 1, 20, 1);
-  descriptors.AddDescriptor(1, 20, RawPcDescriptors::kDeopt, 2, 30, 0);
-  descriptors.AddDescriptor(2, 30, RawPcDescriptors::kOther, 3, 40, 1);
-  descriptors.AddDescriptor(3, 10, RawPcDescriptors::kOther, 4, 40, 2);
-  descriptors.AddDescriptor(4, 10, RawPcDescriptors::kOther, 5, 80, 3);
-  descriptors.AddDescriptor(5, 80, RawPcDescriptors::kOther, 6, 150, 3);
+  descriptors ^= builder->FinalizePcDescriptors(0);
 
   extern void GenerateIncrement(Assembler* assembler);
   Assembler _assembler_;
@@ -2919,18 +2922,19 @@ TEST_CASE(PcDescriptors) {
 }
 
 
-TEST_CASE(PcDescriptorsCompressed) {
-  const int kNumEntries = 6;
-  // Add PcDescriptors to the code.
+TEST_CASE(PcDescriptorsLargeDeltas) {
+  DescriptorList* builder = new DescriptorList(0);
+
+  // kind, pc_offset, deopt_id, token_pos, try_index
+  builder->AddDescriptor(RawPcDescriptors::kOther, 100, 1, 200, 1);
+  builder->AddDescriptor(RawPcDescriptors::kDeopt, 200, 2, 300, 0);
+  builder->AddDescriptor(RawPcDescriptors::kOther, 300, 3, 400, 1);
+  builder->AddDescriptor(RawPcDescriptors::kOther, 100, 4, 0, 2);
+  builder->AddDescriptor(RawPcDescriptors::kOther, 100, 5, 800, 3);
+  builder->AddDescriptor(RawPcDescriptors::kOther, 800, 6, 150, 3);
+
   PcDescriptors& descriptors = PcDescriptors::Handle();
-  // PcDescriptors have no try-index.
-  descriptors ^= PcDescriptors::New(kNumEntries, false);
-  descriptors.AddDescriptor(0, 10, RawPcDescriptors::kOther, 1, 20, -1);
-  descriptors.AddDescriptor(1, 20, RawPcDescriptors::kDeopt, 2, 30, -1);
-  descriptors.AddDescriptor(2, 30, RawPcDescriptors::kOther, 3, 40, -1);
-  descriptors.AddDescriptor(3, 10, RawPcDescriptors::kOther, 4, 40, -1);
-  descriptors.AddDescriptor(4, 10, RawPcDescriptors::kOther, 5, 80, -1);
-  descriptors.AddDescriptor(5, 80, RawPcDescriptors::kOther, 6, 150, -1);
+  descriptors ^= builder->FinalizePcDescriptors(0);
 
   extern void GenerateIncrement(Assembler* assembler);
   Assembler _assembler_;
@@ -2944,26 +2948,37 @@ TEST_CASE(PcDescriptorsCompressed) {
   PcDescriptors::Iterator iter(pc_descs, RawPcDescriptors::kAnyKind);
 
   EXPECT_EQ(true, iter.MoveNext());
-  EXPECT_EQ(static_cast<uword>(10), iter.PcOffset());
-  EXPECT_EQ(-1, iter.TryIndex());
+  EXPECT_EQ(200, iter.TokenPos());
+  EXPECT_EQ(1, iter.TryIndex());
+  EXPECT_EQ(static_cast<uword>(100), iter.PcOffset());
   EXPECT_EQ(1, iter.DeoptId());
-  EXPECT_EQ(20, iter.TokenPos());
+  EXPECT_EQ(RawPcDescriptors::kOther, iter.Kind());
 
   EXPECT_EQ(true, iter.MoveNext());
+  EXPECT_EQ(300, iter.TokenPos());
+  EXPECT_EQ(RawPcDescriptors::kDeopt, iter.Kind());
+
   EXPECT_EQ(true, iter.MoveNext());
+  EXPECT_EQ(400, iter.TokenPos());
+
   EXPECT_EQ(true, iter.MoveNext());
+  EXPECT_EQ(0, iter.TokenPos());
+
   EXPECT_EQ(true, iter.MoveNext());
+  EXPECT_EQ(800, iter.TokenPos());
+
   EXPECT_EQ(true, iter.MoveNext());
+  EXPECT_EQ(150, iter.TokenPos());
 
-  EXPECT_EQ(-1, iter.TryIndex());
-  EXPECT_EQ(static_cast<uword>(80), iter.PcOffset());
+  EXPECT_EQ(3, iter.TryIndex());
+  EXPECT_EQ(static_cast<uword>(800), iter.PcOffset());
   EXPECT_EQ(150, iter.TokenPos());
+  EXPECT_EQ(RawPcDescriptors::kOther, iter.Kind());
 
   EXPECT_EQ(false, iter.MoveNext());
 }
 
 
-
 static RawClass* CreateTestClass(const char* name) {
   const String& class_name = String::Handle(Symbols::New(name));
   const Class& cls = Class::Handle(