Fixes ABI bug in MIPS.

runtime/vm/stub_code_mips.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_MIPS)
 
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/compiler.h"
@@ skipping 66 matching lines @@
   // bits kClosureFunctionBit and kInstanceFunctionBit in argc_tag_.
   ASSERT(argc_tag_offset == 1 * kWordSize);
   __ mov(A1, S4);  // Set argc in NativeArguments.
 
   ASSERT(argv_offset == 2 * kWordSize);
   __ sll(A2, S4, 2);
   __ addu(A2, FP, A2);  // Compute argv.
   // Set argv in NativeArguments.
   __ addiu(A2, A2, Immediate(exitframe_last_param_slot_from_fp * kWordSize));
 
+
   // Call runtime or redirection via simulator.
-  __ jalr(S5);
+  // We defensively always jalr through T9 because it is sometimes required by
+  // the MIPS ABI.
+  __ mov(T9, S5);
+  __ jalr(T9);
+
     ASSERT(retval_offset == 3 * kWordSize);
   // Retval is next to 1st argument.
   __ delay_slot()->addiu(A3, A2, Immediate(kWordSize));
   __ TraceSimMsg("CallToRuntimeStub return");
 
   // Reset exit frame information in Isolate structure.
   __ sw(ZR, Address(CTX, Isolate::top_exit_frame_info_offset()));
 
   // Load Context pointer from Isolate structure into A2.
   __ lw(A2, Address(CTX, Isolate::top_context_offset()));
@@ skipping 100 matching lines @@
   __ AndImmediate(CMPRES1, A1, NativeArguments::AutoSetupScopeMask());
   __ beq(CMPRES1, ZR, &leaf_call);
 
   __ mov(A1, T5);  // Pass the function entrypoint.
   __ ReserveAlignedFrameSpace(2 * kWordSize);  // Just passing A0, A1.
   // Call native wrapper function or redirection via simulator.
 #if defined(USING_SIMULATOR)
   uword entry = reinterpret_cast<uword>(NativeEntry::NativeCallWrapper);
   entry = Simulator::RedirectExternalReference(
       entry, Simulator::kNativeCall, NativeEntry::kNumCallWrapperArguments);
-  __ LoadImmediate(T5, entry);
-  __ jalr(T5);
+  __ LoadImmediate(T9, entry);
+  __ jalr(T9);
 #else
   __ BranchLink(&NativeEntry::NativeCallWrapperLabel());
 #endif
   __ TraceSimMsg("CallNativeCFunctionStub return");
   __ b(&done);
 
   __ Bind(&leaf_call);
   // Call native function or redirection via simulator.
   __ ReserveAlignedFrameSpace(kWordSize);  // Just passing A0.
-  __ jalr(T5);
+
+
+  // We defensively always jalr through T9 because it is sometimes required by
+  // the MIPS ABI.
+  __ mov(T9, T5);
+  __ jalr(T9);
 
   __ Bind(&done);
 
   // Reset exit frame information in Isolate structure.
   __ sw(ZR, Address(CTX, Isolate::top_exit_frame_info_offset()));
 
   // Load Context pointer from Isolate structure into A2.
   __ lw(A2, Address(CTX, Isolate::top_context_offset()));
 
   // Load null.
@@ skipping 69 matching lines @@
   __ addiu(SP, SP, Immediate(-4 * kWordSize));
   __ sw(A3, Address(SP, 3 * kWordSize));
   __ sw(A2, Address(SP, 2 * kWordSize));
   __ sw(A1, Address(SP, 1 * kWordSize));
   __ sw(A0, Address(SP, 0 * kWordSize));
   __ mov(A0, SP);  // Pass the pointer to the NativeArguments.
 
   __ ReserveAlignedFrameSpace(kWordSize);  // Just passing A0.
 
   // Call native function or redirection via simulator.
-  __ jalr(T5);
+
+  // We defensively always jalr through T9 because it is sometimes required by
+  // the MIPS ABI.
+  __ mov(T9, T5);
+  __ jalr(T9);
   __ TraceSimMsg("CallNativeCFunctionStub return");
 
   // Reset exit frame information in Isolate structure.
   __ sw(ZR, Address(CTX, Isolate::top_exit_frame_info_offset()));
 
   // Load Context pointer from Isolate structure into A2.
   __ lw(A2, Address(CTX, Isolate::top_context_offset()));
 
   // Load null.
   __ LoadImmediate(TMP, reinterpret_cast<intptr_t>(Object::null()));
@@ skipping 695 matching lines @@
   __ Bind(&push_arguments);
   __ lw(A3, Address(A2));
   __ Push(A3);
   __ addiu(A1, A1, Immediate(1));
   __ BranchSignedLess(A1, T1, &push_arguments);
   __ delay_slot()->addiu(A2, A2, Immediate(kWordSize));
 
   __ Bind(&done_push_arguments);
 
   // Call the Dart code entrypoint.
+  // We are calling into Dart code, here, so there is no need to call through
+  // T9 to match the ABI.
   __ jalr(A0);  // S4 is the arguments descriptor array.
   __ TraceSimMsg("InvokeDartCodeStub return");
 
   // Read the saved new Context pointer.
   __ lw(CTX, Address(FP, kNewContextOffsetFromFp));
   __ lw(CTX, Address(CTX, VMHandles::kOffsetOfRawPtrInHandle));
 
   // Get rid of arguments pushed on the stack.
   __ AddImmediate(SP, FP, kSavedContextSlotFromEntryFp * kWordSize);
 
@@ skipping 1376 matching lines @@
   const Register right = T0;
   __ lw(left, Address(SP, 1 * kWordSize));
   __ lw(right, Address(SP, 0 * kWordSize));
   GenerateIdenticalWithNumberCheckStub(assembler, left, right, temp1, temp2);
   __ Ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS