Landing for Zaheer Ahmad.

src/arm/code-stubs-arm.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 3311 matching lines @@
   // sp: stack pointer  (restored as callee's sp after C call)
   // cp: current context  (C callee-saved)
 
   // Result returned in r0 or r0+r1 by default.
 
   // NOTE: Invocations of builtins may return failure objects
   // instead of a proper result. The builtin entry handles
   // this by performing a garbage collection and retrying the
   // builtin once.
 
+  // Compute the argv pointer in a callee-saved register.
+  __ add(r6, sp, Operand(r0, LSL, kPointerSizeLog2));
+  __ sub(r6, r6, Operand(kPointerSize));
+
   // Enter the exit frame that transitions from JavaScript to C++.
   __ EnterExitFrame(save_doubles_);
 
+  // Setup argc and the builtin function in callee-saved registers.
+  __ mov(r4, Operand(r0));
+  __ mov(r5, Operand(r1));
+
   // r4: number of arguments (C callee-saved)
   // r5: pointer to builtin function (C callee-saved)
   // r6: pointer to first argument (C callee-saved)
 
   Label throw_normal_exception;
   Label throw_termination_exception;
   Label throw_out_of_memory_exception;
 
   // Call into the runtime system.
   GenerateCore(masm,
@@ skipping 2380 matching lines @@
   __ CallExternalReference(miss, 3);
   __ LeaveInternalFrame();
   // Compute the entry point of the rewritten stub.
   __ add(r2, r0, Operand(Code::kHeaderSize - kHeapObjectTag));
   // Restore registers.
   __ pop(lr);
   __ pop(r0);
   __ pop(r1);
   __ Jump(r2);
 }
 

[Erik Corry, 2011/02/04 09:55:55]

Missing blank line.

[antonm, 2011/02/04 12:59:45]

Done.

+void DirectCEntryStub::Generate(MacroAssembler* masm) {
+  __ ldr(pc, MemOperand(sp, 0));
+}
+

[Erik Corry, 2011/02/04 09:55:55]

and here

[antonm, 2011/02/04 12:59:45]

Done.

+void DirectCEntryStub::GenerateCall(MacroAssembler* masm,
+                                    ApiFunction *function) {
+  __ mov(lr, Operand(reinterpret_cast<intptr_t>(GetCode().location()),
+                     RelocInfo::CODE_TARGET));
+  // Push return address (accessible to GC through exit frame pc).
+  ExternalReference ref =
+      ExternalReference(function, ExternalReference::DIRECT_CALL);
+  __ mov(r2, Operand(reinterpret_cast<intptr_t>(ref.address())));

[Erik Corry, 2011/02/04 09:55:55]

There is a constructor for Operand that takes an external reference.  I think
you have to use that otherwise this doesn't work correctly with snapshots.  The
snapshot code needs the reloc information from a real Operand in case the
destination is different in mksnapshot and the final executable.

[antonm, 2011/02/04 12:59:45]

Done.

+  __ add(ip, pc, Operand(4));

[Erik Corry, 2011/02/04 09:55:55]

It seems to me that omitting this add and just using ip in the next instruction
would achieve the same.  Pc is always 8 bytes ahead of the actual instruction
executing so that should be the same.

[antonm, 2011/02/04 12:59:45]

Hmm, ip would have any garbage then.  Am I missing something.

[Zaheer, 2011/02/04 13:08:05]

I think Erik meant pc.

[Erik Corry, 2011/02/04 13:19:52]

No you are right of course.

+  __ str(ip, MemOperand(sp, 0));
+  __ Jump(r2);  // Call the api function.
+}
 

[Erik Corry, 2011/02/04 09:55:55]

and missing blank line here

[antonm, 2011/02/04 12:59:45]

Done.

 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM