First part of new ICData infrastructure: use a wrapper object instead of an array.

runtime/vm/stub_code_ia32.cc

Index: runtime/vm/stub_code_ia32.cc
===================================================================
--- runtime/vm/stub_code_ia32.cc	(revision 4401)
+++ runtime/vm/stub_code_ia32.cc	(working copy)
@@ -7,7 +7,6 @@
 
 #include "vm/code_generator.h"
 #include "vm/compiler.h"
-#include "vm/ic_data.h"
 #include "vm/object_store.h"
 #include "vm/pages.h"
 #include "vm/resolver.h"
@@ -364,8 +363,7 @@
   __ cmpl(EDI, raw_null);
   __ j(EQUAL, &not_found, Assembler::kNearJump);
 
-  ASSERT(ICData::kNameIndex == 0);
-  __ cmpl(EDI, FieldAddress(ECX, Array::data_offset()));
+  __ cmpl(EDI, FieldAddress(ECX, ICData::target_name_offset()));
   __ j(NOT_EQUAL, &next_iteration, Assembler::kNearJump);
 
   // Name found, check total argument count and named argument count.
@@ -1536,7 +1534,7 @@
 
 
 // Generate inline cache check for 'num_args'.
-//  ECX: Inline cache data array.
+//  ECX: Inline cache data object.
 //  EDX: Arguments array.
 //  TOS(0): return address
 // Control flow:
@@ -1551,7 +1549,7 @@
   ASSERT(num_args > 0);
   // Get receiver.
   __ movl(EAX, FieldAddress(EDX, Array::data_offset()));
-  __ movl(EAX, Address(ESP, EAX, TIMES_2, 0));  // EAX is Smi.
+  __ movl(EAX, Address(ESP, EAX, TIMES_2, 0));  // EAX (argument_count) is Smi.
 
   Label get_class, ic_miss;
   __ call(&get_class);
@@ -1561,11 +1559,9 @@
 #if defined(DEBUG)
   { Label ok;
     // Check that the IC data array has NumberOfArgumentsChecked() == num_args.
-    __ movl(EBX, FieldAddress(ECX,
-        Array::data_offset() + ICData::kNumArgsCheckedIndex * kWordSize));
-    const Immediate value =
-        Immediate(reinterpret_cast<int32_t>(Smi::New(num_args)));
-    __ cmpl(EBX, value);
+    // 'num_args_tested' is stored as an untagged int.
+    __ movl(EBX, FieldAddress(ECX, ICData::num_args_tested_offset()));
+    __ cmpl(EBX, Immediate(num_args));
     __ j(EQUAL, &ok, Assembler::kNearJump);
     __ Stop("Incorrect stub for IC data");
     __ Bind(&ok);
@@ -1574,10 +1570,11 @@
 
   // Loop that checks if there is an IC data match.
   // EAX: receiver's class.
-  // ECX: IC data array (preserved).
-  __ leal(EBX, FieldAddress(ECX,
-      Array::data_offset() + ICData::kChecksStartIndex * kWordSize));
-  // EBX: pointing to a class to check against (into IC data array).
+  // ECX: IC data object (preserved).
+  __ movl(EBX, FieldAddress(ECX, ICData::ic_data_offset()));
+  // EBX: ic_data_array with check entries: classes and target functions.
+  __ leal(EBX, FieldAddress(EBX, Array::data_offset()));
+  // EBX: points directly to the first ic data array element.
   const Immediate raw_null =
       Immediate(reinterpret_cast<intptr_t>(Object::null()));
   Label loop, found;
@@ -1590,24 +1587,29 @@
     __ cmpl(EDI, raw_null);   // Done?
     __ j(NOT_EQUAL, &loop, Assembler::kNearJump);
   } else if (num_args == 2) {
+    // EDI: class to check.
     Label no_match;
     __ Bind(&loop);
-    __ movl(EDI, Address(EBX, 0));  // Get class from IC data to check.
-    // Get receiver.
+    // Get class from IC data to check.
+    __ movl(EDI, Address(EBX, 0));
+    // Get receiver using argument descriptor in EDX.
     __ movl(EAX, FieldAddress(EDX, Array::data_offset()));
-    __ movl(EAX, Address(ESP, EAX, TIMES_2, 0));  // EAX is Smi.
+    __ movl(EAX, Address(ESP, EAX, TIMES_2, 0));  // EAX (arg. count) is Smi.
     __ call(&get_class);
     __ cmpl(EAX, EDI);  // Match?
     __ j(NOT_EQUAL, &no_match, Assembler::kNearJump);
-    // Check second.
-    __ movl(EDI, Address(EBX, kWordSize));  // Get class from IC data to check.
+    // Check second class/argument.
+    // Get class from IC data to check.
+    __ movl(EDI, Address(EBX, kWordSize));
     // Get next argument.
     __ movl(EAX, FieldAddress(EDX, Array::data_offset()));
-    __ movl(EAX, Address(ESP, EAX, TIMES_2, -kWordSize));  // EAX is Smi.
+    __ movl(EAX, Address(ESP, EAX, TIMES_2, -kWordSize));
+    // EAX (argument count) is Smi.
     __ call(&get_class);
     __ cmpl(EAX, EDI);  // Match?
     __ j(EQUAL, &found, Assembler::kNearJump);
     __ Bind(&no_match);
+    // Each test entry has (1 + num_args) array elements.
     __ addl(EBX, Immediate(kWordSize * (1 + num_args)));  // Next element.
     __ cmpl(EDI, raw_null);   // Done?
     __ j(NOT_EQUAL, &loop, Assembler::kNearJump);