Adds intrinsics for array allocation and string charAt.

runtime/vm/intrinsifier_arm.cc

Index: runtime/vm/intrinsifier_arm.cc
===================================================================
--- runtime/vm/intrinsifier_arm.cc	(revision 39452)
+++ runtime/vm/intrinsifier_arm.cc	(working copy)
@@ -22,6 +22,116 @@
 #define __ assembler->
 
 
+void Intrinsifier::ObjectArrayAllocate(Assembler* assembler) {
+  Label fall_through;
+  const intptr_t kTypeArgumentsOffset = 1 * kWordSize;
+  const intptr_t kLengthOffset = 0 * kWordSize;
+
+  __ ldr(R1, Address(SP, kTypeArgumentsOffset));
+  __ ldr(R2, Address(SP, kLengthOffset));
+
+  // Compute the size to be allocated, it is based on the array length
+  // and is computed as:
+  // RoundedAllocationSize((array_length * kwordSize) + sizeof(RawArray)).
+  __ MoveRegister(R3, R2);   // Array length.
+
+  // Check that length is a positive Smi.
+  __ tst(R3, Operand(kSmiTagMask));
+  __ b(&fall_through, NE);
+  __ cmp(R3, Operand(0));
+  __ b(&fall_through, LT);
+
+  // Check for maximum allowed length.
+  const intptr_t max_len =
+      reinterpret_cast<int32_t>(Smi::New(Array::kMaxElements));
+  __ CompareImmediate(R3, max_len);
+  __ b(&fall_through, GT);
+
+  const intptr_t fixed_size = sizeof(RawArray) + kObjectAlignment - 1;
+  __ LoadImmediate(R8, fixed_size);
+  __ add(R8, R8, Operand(R3, LSL, 1));  // R3 is  a Smi.
+  ASSERT(kSmiTagShift == 1);
+  __ bic(R8, R8, Operand(kObjectAlignment - 1));
+
+  // R8: Allocation size.
+
+  Isolate* isolate = Isolate::Current();
+  Heap* heap = isolate->heap();
+
+  __ LoadImmediate(R6, heap->TopAddress());
+  __ ldr(R0, Address(R6, 0));  // Potential new object start.
+  __ adds(R7, R0, Operand(R8));  // Potential next object start.
+  __ b(&fall_through, VS);
+
+  // Check if the allocation fits into the remaining space.
+  // R0: potential new object start.
+  // R7: potential next object start.
+  // R8: allocation size.
+  __ LoadImmediate(R3, heap->EndAddress());
+  __ ldr(R3, Address(R3, 0));
+  __ cmp(R7, Operand(R3));
+  __ b(&fall_through, CS);
+
+  // Successfully allocated the object(s), now update top to point to
+  // next object start and initialize the object.
+  __ str(R7, Address(R6, 0));
+  __ add(R0, R0, Operand(kHeapObjectTag));
+  __ UpdateAllocationStatsWithSize(kArrayCid, R8, R4);
+
+  // Initialize the tags.
+  // R0: new object start as a tagged pointer.
+  // R7: new object end address.
+  // R8: allocation size.
+  {
+    const intptr_t shift = RawObject::kSizeTagPos - kObjectAlignmentLog2;
+    const Class& cls = Class::Handle(isolate->object_store()->array_class());
+
+    __ CompareImmediate(R8, RawObject::SizeTag::kMaxSizeTag);
+    __ mov(R8, Operand(R8, LSL, shift), LS);
+    __ mov(R8, Operand(0), HI);
+
+    // Get the class index and insert it into the tags.
+    // R8: size and bit tags.
+    __ LoadImmediate(TMP, RawObject::ClassIdTag::encode(cls.id()));
+    __ orr(R8, R8, Operand(TMP));
+    __ str(R8, FieldAddress(R0, Array::tags_offset()));  // Store tags.
+  }
+
+  // R0: new object start as a tagged pointer.
+  // R7: new object end address.
+  // Store the type argument field.
+  __ StoreIntoObjectNoBarrier(R0,
+                              FieldAddress(R0, Array::type_arguments_offset()),
+                              R1);
+
+  // Set the length field.
+  __ StoreIntoObjectNoBarrier(R0,
+                              FieldAddress(R0, Array::length_offset()),
+                              R2);
+
+  // Initialize all array elements to raw_null.
+  // R0: new object start as a tagged pointer.
+  // R7: new object end address.
+  // R8: iterator which initially points to the start of the variable
+  // data area to be initialized.
+  // R3: null
+  __ LoadImmediate(R3, reinterpret_cast<intptr_t>(Object::null()));
+  __ AddImmediate(R8, R0, sizeof(RawArray) - kHeapObjectTag);
+
+  Label init_loop;
+  __ Bind(&init_loop);
+  __ cmp(R8, Operand(R7));
+  __ str(R3, Address(R8, 0), CC);
+  __ AddImmediate(R8, kWordSize, CC);
+  __ b(&init_loop, CC);
+
+  __ Ret();  // Returns the newly allocated object in R0.
+  // Unable to allocate the array using the fast inline code, just call
+  // into the runtime.
+  __ Bind(&fall_through);
+}
+
+
 void Intrinsifier::ObjectArrayLength(Assembler* assembler) {
   __ ldr(R0, Address(SP, 0 * kWordSize));
   __ ldr(R0, FieldAddress(R0, Array::length_offset()));
@@ -1411,6 +1521,49 @@
 }
 
 
+void Intrinsifier::StringBase_charAt(Assembler* assembler) {
+  Label fall_through, try_two_byte_string;
+
+  __ ldr(R1, Address(SP, 0 * kWordSize));  // Index.
+  __ ldr(R0, Address(SP, 1 * kWordSize));  // String.
+  __ tst(R1, Operand(kSmiTagMask));
+  __ b(&fall_through, NE);  // Index is not a Smi.
+  // Range check.
+  __ ldr(R2, FieldAddress(R0, String::length_offset()));
+  __ cmp(R1, Operand(R2));
+  __ b(&fall_through, CS);  // Runtime throws exception.
+
+  __ CompareClassId(R0, kOneByteStringCid, R3);
+  __ b(&try_two_byte_string, NE);
+  __ SmiUntag(R1);
+  __ AddImmediate(R0, OneByteString::data_offset() - kHeapObjectTag);
+  __ ldrb(R1, Address(R0, R1));
+  __ CompareImmediate(R1, Symbols::kNumberOfOneCharCodeSymbols);
+  __ b(&fall_through, GE);
+  __ LoadImmediate(R0,
+                   reinterpret_cast<uword>(Symbols::PredefinedAddress()));
+  __ AddImmediate(R0, Symbols::kNullCharCodeSymbolOffset * kWordSize);
+  __ ldr(R0, Address(R0, R1, LSL, 2));
+  __ Ret();
+
+  __ Bind(&try_two_byte_string);
+  __ CompareClassId(R0, kTwoByteStringCid, R3);
+  __ b(&fall_through, NE);
+  ASSERT(kSmiTagShift == 1);
+  __ AddImmediate(R0, TwoByteString::data_offset() - kHeapObjectTag);
+  __ ldrh(R1, Address(R0, R1));
+  __ CompareImmediate(R1, Symbols::kNumberOfOneCharCodeSymbols);
+  __ b(&fall_through, GE);
+  __ LoadImmediate(R0,
+                   reinterpret_cast<uword>(Symbols::PredefinedAddress()));
+  __ AddImmediate(R0, Symbols::kNullCharCodeSymbolOffset * kWordSize);
+  __ ldr(R0, Address(R0, R1, LSL, 2));
+  __ Ret();
+
+  __ Bind(&fall_through);
+}
+
+
 void Intrinsifier::StringBaseIsEmpty(Assembler* assembler) {
   __ ldr(R0, Address(SP, 0 * kWordSize));
   __ ldr(R0, FieldAddress(R0, String::length_offset()));