VM: Use current isolate as immediate in per-isolate stubs.

runtime/vm/stub_code_arm.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_ARM)
 
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/cpu.h"
@@ skipping 747 matching lines @@
 
   // The new Context structure contains a pointer to the current Isolate
   // structure. Cache the Context pointer in the CTX register so that it is
   // available in generated code and calls to Isolate::Current() need not be
   // done. The assumption is that this register will never be clobbered by
   // compiled or runtime stub code.
 
   // Cache the new Context pointer into CTX while executing Dart code.
   __ ldr(CTX, Address(R3, VMHandles::kOffsetOfRawPtrInHandle));
 
-  // Load Isolate pointer from Context structure into temporary register R8.
-  __ ldr(R8, FieldAddress(CTX, Context::isolate_offset()));
+  // Load Isolate pointer into temporary register R8.
+  __ LoadImmediate(R8, Isolate::CurrentAddress());

[Ivan Posva, 2014/09/18 17:31:12]

On second thought I will add a LoadIsolate() to the macro assemblers and remove
CurrentAddress().

 
   // Save the current VMTag on the stack.
   ASSERT(kSavedVMTagSlotFromEntryFp == -25);
   __ LoadFromOffset(kWord, R5, R8, Isolate::vm_tag_offset());
   __ Push(R5);
 
   // Mark that the isolate is executing Dart code.
   __ LoadImmediate(R5, VMTag::kDartTagId);
   __ StoreToOffset(kWord, R5, R8, Isolate::vm_tag_offset());
 
@@ skipping 45 matching lines @@
   // Call the Dart code entrypoint.
   __ blx(R0);  // R4 is the arguments descriptor array.
 
   // Read the saved new Context pointer.
   __ ldr(CTX, Address(FP, kNewContextOffsetFromFp));
   __ ldr(CTX, Address(CTX, VMHandles::kOffsetOfRawPtrInHandle));
 
   // Get rid of arguments pushed on the stack.
   __ AddImmediate(SP, FP, kSavedContextSlotFromEntryFp * kWordSize);
 
-  // Load Isolate pointer from Context structure into CTX. Drop Context.
-  __ ldr(CTX, FieldAddress(CTX, Context::isolate_offset()));
+  // Load Isolate pointer into CTX. Drop Context.
+  __ LoadImmediate(CTX, Isolate::CurrentAddress());
 
   // Restore the saved Context pointer into the Isolate structure.
   // Uses R4 as a temporary register for this.
   // Restore the saved top exit frame info back into the Isolate structure.
   // Uses R5 as a temporary register for this.
   __ PopList((1 << R4) | (1 << R5));
   __ StoreToOffset(kWord, R4, CTX, Isolate::top_context_offset());
   __ StoreToOffset(kWord, R5, CTX, Isolate::top_exit_frame_info_offset());
 
   // Restore the current VMTag from the stack.
@@ skipping 79 matching lines @@
     __ LoadImmediate(IP, RawObject::ClassIdTag::encode(context_class.id()));
     __ orr(R2, R2, Operand(IP));
     __ str(R2, FieldAddress(R0, Context::tags_offset()));
 
     // Setup up number of context variables field.
     // R0: new object.
     // R1: number of context variables as integer value (not object).
     __ str(R1, FieldAddress(R0, Context::num_variables_offset()));
 
     // Setup isolate field.
-    // Load Isolate pointer from Context structure into R2.
+    // Load Isolate pointer into R2.
     // R0: new object.
     // R1: number of context variables.
-    __ ldr(R2, FieldAddress(CTX, Context::isolate_offset()));
+    __ LoadImmediate(R2, Isolate::CurrentAddress());
     // R2: isolate, not an object.
     __ str(R2, FieldAddress(R0, Context::isolate_offset()));
 
     // Setup the parent field.
     // R0: new object.
     // R1: number of context variables.
     __ LoadImmediate(R2, reinterpret_cast<intptr_t>(Object::null()));
     __ str(R2, FieldAddress(R0, Context::parent_offset()));
 
     // Initialize the context variables.
@@ skipping 47 matching lines @@
   __ ldr(R2, FieldAddress(R0, Object::tags_offset()));
   __ tst(R2, Operand(1 << RawObject::kRememberedBit));
   __ b(&add_to_buffer, EQ);
   __ PopList((1 << R1) | (1 << R2) | (1 << R3));
   __ Ret();
 
   __ Bind(&add_to_buffer);
   __ orr(R2, R2, Operand(1 << RawObject::kRememberedBit));
   __ str(R2, FieldAddress(R0, Object::tags_offset()));
 
-  // Load the isolate out of the context.
+  // Load the isolate.
   // Spilled: R1, R2, R3.
   // R0: address being stored.
-  __ ldr(R1, FieldAddress(CTX, Context::isolate_offset()));
+  __ LoadImmediate(R1, Isolate::CurrentAddress());
 
   // Load the StoreBuffer block out of the isolate. Then load top_ out of the
   // StoreBufferBlock and add the address to the pointers_.
   // R1: isolate.
   __ ldr(R1, Address(R1, Isolate::store_buffer_offset()));
   __ ldr(R2, Address(R1, StoreBufferBlock::top_offset()));
   __ add(R3, R1, Operand(R2, LSL, 2));
   __ str(R0, Address(R3, StoreBufferBlock::pointers_offset()));
 
   // Increment top_ and check for overflow.
   // R2: top_.
   // R1: StoreBufferBlock.
   Label L;
   __ add(R2, R2, Operand(1));
   __ str(R2, Address(R1, StoreBufferBlock::top_offset()));
   __ CompareImmediate(R2, StoreBufferBlock::kSize);
   // Restore values.
   __ PopList((1 << R1) | (1 << R2) | (1 << R3));
   __ b(&L, EQ);
   __ Ret();
 
   // Handle overflow: Call the runtime leaf function.
   __ Bind(&L);
   // Setup frame, push callee-saved registers.
 
   __ EnterCallRuntimeFrame(0 * kWordSize);
-  __ ldr(R0, FieldAddress(CTX, Context::isolate_offset()));
+  __ LoadImmediate(R0, Isolate::CurrentAddress());
   __ CallRuntime(kStoreBufferBlockProcessRuntimeEntry, 1);
   // Restore callee-saved registers, tear down frame.
   __ LeaveCallRuntimeFrame();
   __ Ret();
 }
 
 
 // Called for inline allocation of objects.
 // Input parameters:
 //   LR : return address.
@@ skipping 278 matching lines @@
     __ ldr(R6, FieldAddress(R5, ICData::state_bits_offset()));
     ASSERT(ICData::NumArgsTestedShift() == 0);  // No shift needed.
     __ and_(R6, R6, Operand(ICData::NumArgsTestedMask()));
     __ CompareImmediate(R6, num_args);
     __ b(&ok, EQ);
     __ Stop("Incorrect stub for IC data");
     __ Bind(&ok);
   }
 #endif  // DEBUG
 
-  Label stepping, done_stepping;
 
   // Check single stepping.
-  __ ldr(R6, FieldAddress(CTX, Context::isolate_offset()));
+  Label stepping, done_stepping;
+  __ LoadImmediate(R6, Isolate::CurrentAddress());
   __ ldrb(R6, Address(R6, Isolate::single_step_offset()));
   __ CompareImmediate(R6, 0);
   __ b(&stepping, NE);
   __ Bind(&done_stepping);
 
   if (kind != Token::kILLEGAL) {
     Label not_smi_or_overflow;
     EmitFastSmiOp(assembler, kind, num_args, &not_smi_or_overflow);
     __ Bind(&not_smi_or_overflow);
   }
@@ skipping 200 matching lines @@
     __ and_(R6, R6, Operand(ICData::NumArgsTestedMask()));
     __ CompareImmediate(R6, 0);
     __ b(&ok, EQ);
     __ Stop("Incorrect IC data for unoptimized static call");
     __ Bind(&ok);
   }
 #endif  // DEBUG
 
   // Check single stepping.
   Label stepping, done_stepping;
-  __ ldr(R6, FieldAddress(CTX, Context::isolate_offset()));
+  __ LoadImmediate(R6, Isolate::CurrentAddress());
   __ ldrb(R6, Address(R6, Isolate::single_step_offset()));
   __ CompareImmediate(R6, 0);
   __ b(&stepping, NE);
   __ Bind(&done_stepping);
 
   // R5: IC data object (preserved).
   __ ldr(R6, FieldAddress(R5, ICData::ic_data_offset()));
   // R6: ic_data_array with entries: target functions and count.
   __ AddImmediate(R6, R6, Array::data_offset() - kHeapObjectTag);
   // R6: points directly to the first ic data array element.
@@ skipping 401 matching lines @@
   const Register right = R0;
   __ ldr(left, Address(SP, 1 * kWordSize));
   __ ldr(right, Address(SP, 0 * kWordSize));
   GenerateIdenticalWithNumberCheckStub(assembler, left, right, temp);
   __ Ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM