Preserves callee-saved FPU registers on ARM

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/compiler.h"
@@ skipping 764 matching lines @@
 //   LR : points to return address.
 //   R0 : entrypoint of the Dart function to call.
 //   R1 : arguments descriptor array.
 //   R2 : arguments array.
 //   R3 : new context containing the current isolate pointer.
 void StubCode::GenerateInvokeDartCodeStub(Assembler* assembler) {
   // Save frame pointer coming in.
   __ EnterStubFrame();
 
   // Save new context and C++ ABI callee-saved registers.
-  const intptr_t kNewContextOffset =
+  const intptr_t kNewContextOffsetFromFp =
       -(1 + kAbiPreservedCpuRegCount) * kWordSize;
   __ PushList((1 << R3) | kAbiPreservedCpuRegs);
 
+  const DRegister firstd = EvenDRegisterOf(kAbiFirstPreservedFpuReg);
+  ASSERT(2 * kAbiPreservedFpuRegCount < 16);
+  // Save FPU registers. 2 D registers per Q register.
+  __ vstmd(DB_W, SP, firstd, 2 * kAbiPreservedFpuRegCount);
+
   // 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()));
 
   // Save the top exit frame info. Use R5 as a temporary register.
   // StackFrameIterator reads the top exit frame info saved in this frame.
   __ LoadFromOffset(kWord, R5, R8, Isolate::top_exit_frame_info_offset());
   __ LoadImmediate(R6, 0);
   __ StoreToOffset(kWord, R6, R8, Isolate::top_exit_frame_info_offset());
 
   // Save the old Context pointer. Use R4 as a temporary register.
   // Note that VisitObjectPointers will find this saved Context pointer during
   // GC marking, since it traverses any information between SP and
   // FP - kExitLinkSlotFromEntryFp.
   // EntryFrame::SavedContext reads the context saved in this frame.
   __ LoadFromOffset(kWord, R4, R8, Isolate::top_context_offset());
 
   // The constants kSavedContextSlotFromEntryFp and
   // kExitLinkSlotFromEntryFp must be kept in sync with the code below.
-  ASSERT(kExitLinkSlotFromEntryFp == -9);
-  ASSERT(kSavedContextSlotFromEntryFp == -10);
+  ASSERT(kExitLinkSlotFromEntryFp == -25);
+  ASSERT(kSavedContextSlotFromEntryFp == -26);
   __ PushList((1 << R4) | (1 << R5));
 
-  // The stack pointer is restored after the call to this location.
-  const intptr_t kSavedContextSlotFromEntryFp = -10 * kWordSize;
-
   // Load arguments descriptor array into R4, which is passed to Dart code.
   __ ldr(R4, Address(R1, VMHandles::kOffsetOfRawPtrInHandle));
 
   // Load number of arguments into R5.
   __ ldr(R5, FieldAddress(R4, ArgumentsDescriptor::count_offset()));
   __ SmiUntag(R5);
 
   // Compute address of 'arguments array' data area into R2.
   __ ldr(R2, Address(R2, VMHandles::kOffsetOfRawPtrInHandle));
   __ AddImmediate(R2, R2, Array::data_offset() - kHeapObjectTag);
@@ skipping 10 matching lines @@
   __ AddImmediate(R2, kWordSize);
   __ AddImmediate(R1, 1);
   __ cmp(R1, ShifterOperand(R5));
   __ b(&push_arguments, LT);
   __ Bind(&done_push_arguments);
 
   // Call the Dart code entrypoint.
   __ blx(R0);  // R4 is the arguments descriptor array.
 
   // Read the saved new Context pointer.
-  __ ldr(CTX, Address(FP, kNewContextOffset));
+  __ ldr(CTX, Address(FP, kNewContextOffsetFromFp));
   __ ldr(CTX, Address(CTX, VMHandles::kOffsetOfRawPtrInHandle));
 
   // Get rid of arguments pushed on the stack.
-  __ AddImmediate(SP, FP, kSavedContextSlotFromEntryFp);
+  __ AddImmediate(SP, FP, kSavedContextSlotFromEntryFp * kWordSize);
 
   // Load Isolate pointer from Context structure into CTX. Drop Context.
   __ ldr(CTX, FieldAddress(CTX, Context::isolate_offset()));
 
   // 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 C++ ABI callee-saved registers.
+  // Restore FPU registers. 2 D registers per Q register.
+  __ vldmd(IA_W, SP, firstd, 2 * kAbiPreservedFpuRegCount);
+  // Restore CPU registers.
   __ PopList((1 << R3) | kAbiPreservedCpuRegs);  // Ignore restored R3.
 
   // Restore the frame pointer and return.
   __ LeaveStubFrame();
   __ Ret();
 }
 
 
 // Called for inline allocation of contexts.
 // Input:
@@ skipping 1297 matching lines @@
   __ ldr(left, Address(SP, 4 * kWordSize));
   __ ldr(right, Address(SP, 3 * kWordSize));
   GenerateIdenticalWithNumberCheckStub(assembler, left, right, temp);
   __ PopList((1 << R0) | (1 << R1) | (1 << R2));
   __ Ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM