Add custom typed ICs for pixel array loads.

src/arm/ic-arm.cc

Index: src/arm/ic-arm.cc
===================================================================
--- src/arm/ic-arm.cc	(revision 6508)
+++ src/arm/ic-arm.cc	(working copy)
@@ -501,6 +501,65 @@
 }
 
 
+static void GenerateFastPixelArrayLoad(MacroAssembler* masm,
+                                       Register receiver,
+                                       Register key,
+                                       Register elements_map,
+                                       Register elements,
+                                       Register scratch1,
+                                       Register scratch2,
+                                       Register result,
+                                       Label* not_pixel_array,
+                                       Label* key_not_smi,
+                                       Label* out_of_range) {
+  // Register use:
+  //
+  // receiver - holds the receiver on entry.
+  //            Unchanged unless 'result' is the same register.
+  //
+  // key      - holds the smi key on entry.
+  //            Unchanged unless 'result' is the same register.
+  //
+  // elements - set to be the receiver's elements on exit.
+  //
+  // elements_map - set to be the map of the receiver's elements
+  //            on exit. 
+  //
+  // result   - holds the result of the pixel array load on exit, 
+  //            tagged as a smi if successful.
+  //
+  // Scratch registers:
+  //
+  // scratch1 - holds the receiver's elements, the length of the
+  //            pixel array, the pointer to external elements and
+  //            the untagged result.
+  //
+  // scratch2 - holds the untaged key 
+
+  // Verify that the receiver has pixel array elements.
+  __ ldr(elements, FieldMemOperand(receiver, JSObject::kElementsOffset));
+  __ LoadRoot(scratch1, Heap::kPixelArrayMapRootIndex);
+  __ ldr(elements_map, FieldMemOperand(elements, JSObject::kMapOffset));
+  __ cmp(elements_map, scratch1);
+  __ b(ne, not_pixel_array);
+
+  // Key must be a smi that is in the range of the pixel array.
+  if (key_not_smi != NULL)
+    __ JumpIfNotSmi(key, key_not_smi);

[Mads Ager (chromium), 2011/01/28 10:39:16]

Either make the entire 'if (...) __ JumpIfNotSmi(...);' a one-liner or use
braces around the body.

+  __ ldr(scratch1, FieldMemOperand(elements, PixelArray::kLengthOffset));
+  __ SmiUntag(scratch2, key);
+  __ cmp(scratch2, scratch1);
+  __ b(hs, out_of_range);
+
+  // Perform the indexed load and tag the result as a smi.
+  __ ldr(scratch1,
+         FieldMemOperand(elements, PixelArray::kExternalPointerOffset));
+  __ ldrb(scratch1, MemOperand(scratch1, scratch2));
+  __ SmiTag(r0, scratch1);
+  __ Ret();
+}
+
+
 // Checks whether a key is an array index string or a symbol string.
 // Falls through if a key is a symbol.
 static void GenerateKeyStringCheck(MacroAssembler* masm,
@@ -1189,20 +1248,19 @@
   // r0: key
   // r1: receiver
   __ bind(&check_pixel_array);
-  __ ldr(r4, FieldMemOperand(r1, JSObject::kElementsOffset));
-  __ ldr(r3, FieldMemOperand(r4, HeapObject::kMapOffset));
-  __ LoadRoot(ip, Heap::kPixelArrayMapRootIndex);
-  __ cmp(r3, ip);
-  __ b(ne, &check_number_dictionary);
-  __ ldr(ip, FieldMemOperand(r4, PixelArray::kLengthOffset));
-  __ mov(r2, Operand(key, ASR, kSmiTagSize));
-  __ cmp(r2, ip);
-  __ b(hs, &slow);
-  __ ldr(ip, FieldMemOperand(r4, PixelArray::kExternalPointerOffset));
-  __ ldrb(r2, MemOperand(ip, r2));
-  __ mov(r0, Operand(r2, LSL, kSmiTagSize));  // Tag result as smi.
-  __ Ret();
 
+  GenerateFastPixelArrayLoad(masm,
+                             r1,
+                             r0,
+                             r3,
+                             r4,
+                             r2,
+                             r5,
+                             r0,
+                             &check_number_dictionary,
+                             NULL,
+                             &slow);
+
   __ bind(&check_number_dictionary);
   // Check whether the elements is a number dictionary.
   // r0: key
@@ -1375,6 +1433,41 @@
 }
 
 
+void KeyedLoadIC::GeneratePixelArray(MacroAssembler* masm) {
+  // ---------- S t a t e --------------
+  //  -- lr     : return address
+  //  -- r0     : key
+  //  -- r1     : receiver
+  // -----------------------------------
+
+  // Register usage.
+  Register key = r0;
+  Register receiver = r1;
+
+  Label slow;
+
+  // Verify that it's safe to access the receiver's elements.
+  GenerateKeyedLoadReceiverCheck(
+      masm, receiver, r5, r6,
+      Map::kHasIndexedInterceptor, &slow);
+
+  GenerateFastPixelArrayLoad(masm,
+                             receiver,
+                             key,
+                             r2,
+                             r3,
+                             r4,
+                             r5,
+                             r0,
+                             &slow,
+                             &slow,
+                             &slow);
+
+  __ bind(&slow);
+  GenerateMiss(masm);
+}
+
+
 void KeyedStoreIC::GenerateMiss(MacroAssembler* masm) {
   // ---------- S t a t e --------------
   //  -- r0     : value