ARM: Improve register allocation and constraints....

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 3543 matching lines @@
   // r3: argc
   // [sp+0]: argv
 
   Label invoke, exit;
 
   // Called from C, so do not pop argc and args on exit (preserve sp)
   // No need to save register-passed args
   // Save callee-saved registers (incl. cp and fp), sp, and lr
   __ stm(db_w, sp, kCalleeSaved | lr.bit());
 
+  if (CpuFeatures::IsSupported(VFP3)) {
+    CpuFeatures::Scope scope(VFP3);
+    // Save callee-saved vfp registers.
+    __ vstm(db_w, sp, kFirstCalleeSavedDoubleReg, kLastCalleeSavedDoubleReg);

[Søren Thygesen Gjesse, 2011/06/16 09:38:07]

Oops - isn't this a bug that might have broken the C++ code calling into
JavaScript? If so this should be in a separate change so we can merge it to the
3.x branches.

Also in pre-crankshaft code we do use d8 once in a while.

[Alexandre, 2011/06/16 12:58:48]

Indeed! I'll break it into a separate patch.
If you push the callee-saved on the stack on entry to JS and check their value
when exiting you can see they are trashed...

On 2011/06/16 09:38:07, Søren Gjesse wrote:

+    // Set up reserved registers.
+    __ vmov(d12, 255.0);
+    __ vmov(d13, -0.0);
+    __ vmov(d14, 0.0);
+  }
+
   // Get address of argv, see stm above.
   // r0: code entry
   // r1: function
   // r2: receiver
   // r3: argc
-  __ ldr(r4, MemOperand(sp, (kNumCalleeSaved + 1) * kPointerSize));  // argv
+  __ ldr(r4, MemOperand(sp, (kNumCalleeSaved + 1) * kPointerSize +
+                            kNumDoubleCalleeSaved * kDoubleSize));  // argv
 
   // Push a frame with special values setup to mark it as an entry frame.
   // r0: code entry
   // r1: function
   // r2: receiver
   // r3: argc
   // r4: argv
   Isolate* isolate = masm->isolate();
   __ mov(r8, Operand(-1));  // Push a bad frame pointer to fail if it is used.
   int marker = is_construct ? StackFrame::ENTRY_CONSTRUCT : StackFrame::ENTRY;
@@ skipping 104 matching lines @@
 
   // Reset the stack to the callee saved registers.
   __ add(sp, sp, Operand(-EntryFrameConstants::kCallerFPOffset));
 
   // Restore callee-saved registers and return.
 #ifdef DEBUG
   if (FLAG_debug_code) {
     __ mov(lr, Operand(pc));
   }
 #endif
+
+  if (CpuFeatures::IsSupported(VFP3)) {
+    CpuFeatures::Scope scope(VFP3);
+    // Restore callee-saved vfp registers.
+    __ vldm(ia_w, sp, kFirstCalleeSavedDoubleReg, kLastCalleeSavedDoubleReg);
+  }
+
   __ ldm(ia_w, sp, kCalleeSaved | pc.bit());
 }
 
 
 // Uses registers r0 to r4.
 // Expected input (depending on whether args are in registers or on the stack):
 // * object: r0 or at sp + 1 * kPointerSize.
 // * function: r1 or at sp.
 //
 // An inlined call site may have been generated before calling this stub.
@@ skipping 2698 matching lines @@
   __ mov(result, Operand(0));
   __ Ret();
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM