ARM: Improve register allocation and constraints....

src/arm/code-stubs-arm.cc

Index: src/arm/code-stubs-arm.cc
===================================================================
--- src/arm/code-stubs-arm.cc	(revision 8283)
+++ src/arm/code-stubs-arm.cc	(working copy)
@@ -3561,12 +3561,23 @@
   // 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
@@ -3691,6 +3702,13 @@
     __ 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());
 }