From aad4b0b970c6f2b105873dfd206598b7e262a592 Mon Sep 17 00:00:00 2001
From: David Anderson <danderson@mozilla.com>
Date: Sun, 30 May 2010 14:37:18 -0700
Subject: [PATCH] [JAEGER] Common function for computing obj slot refs;
 improved regalloc on GETGLOBAL.

---
 js/src/methodjit/BaseAssembler.h  | 14 ++++++++++++++
 js/src/methodjit/Compiler.cpp     | 22 ++++------------------
 js/src/methodjit/FrameState-inl.h | 11 ++++++++++-
 js/src/methodjit/FrameState.cpp   |  3 +++
 4 files changed, 31 insertions(+), 19 deletions(-)

diff --git a/js/src/methodjit/BaseAssembler.h b/js/src/methodjit/BaseAssembler.h
index 1330ba3cfd3..f3a9ccab21b 100644
--- a/js/src/methodjit/BaseAssembler.h
+++ b/js/src/methodjit/BaseAssembler.h
@@ -97,6 +97,20 @@ class BaseAssembler : public JSC::MacroAssembler
     static const RegisterID FpReg = JSC::X86Registers::r11;
 #endif
 
+    /*
+     * Finds and returns the address of a known object and slot.
+     */
+    Address objSlotRef(JSObject *obj, RegisterID reg, uint32 slot) {
+        if (slot < JS_INITIAL_NSLOTS) {
+            void *vp = &obj->getSlotRef(slot);
+            move(ImmPtr(vp), reg);
+            return Address(reg, 0);
+        }
+        move(ImmPtr(&obj->dslots), reg);
+        loadPtr(reg, reg);
+        return Address(reg, (slot - JS_INITIAL_NSLOTS) * sizeof(Value));
+    }
+
     /*
      * Prepares for a stub call.
      */
diff --git a/js/src/methodjit/Compiler.cpp b/js/src/methodjit/Compiler.cpp
index 3bf261c559e..f4be4c47c6b 100644
--- a/js/src/methodjit/Compiler.cpp
+++ b/js/src/methodjit/Compiler.cpp
@@ -422,15 +422,8 @@ mjit::Compiler::jsop_setglobal(uint32 index)
     bool popped = PC[JSOP_SETGLOBAL_LENGTH] == JSOP_POP;
 
     RegisterID reg = frame.allocReg();
-    if (slot < JS_INITIAL_NSLOTS) {
-        void *vp = &globalObj->getSlotRef(slot);
-        masm.move(ImmPtr(vp), reg);
-        frame.storeTo(fe, Address(reg, 0), popped);
-    } else {
-        masm.move(ImmPtr(&globalObj->dslots), reg);
-        masm.loadPtr(reg, reg);
-        frame.storeTo(fe, Address(reg, (slot - JS_INITIAL_NSLOTS) * sizeof(Value)), popped);
-    }
+    Address address = masm.objSlotRef(globalObj, reg, slot);
+    frame.storeTo(fe, address, popped);
     frame.freeReg(reg);
 }
 
@@ -441,16 +434,9 @@ mjit::Compiler::jsop_getglobal(uint32 index)
     uint32 slot = script->getGlobalSlot(index);
 
     RegisterID reg = frame.allocReg();
-    if (slot < JS_INITIAL_NSLOTS) {
-        void *vp = &globalObj->getSlotRef(slot);
-        masm.move(ImmPtr(vp), reg);
-        frame.push(Address(reg, 0));
-    } else {
-        masm.move(ImmPtr(&globalObj->dslots), reg);
-        masm.loadPtr(reg, reg);
-        frame.push(Address(reg, (slot - JS_INITIAL_NSLOTS) * sizeof(Value)));
-    }
+    Address address = masm.objSlotRef(globalObj, reg, slot);
     frame.freeReg(reg);
+    frame.push(address);
 }
 
 void
diff --git a/js/src/methodjit/FrameState-inl.h b/js/src/methodjit/FrameState-inl.h
index bb616abf9d0..0db804b546f 100644
--- a/js/src/methodjit/FrameState-inl.h
+++ b/js/src/methodjit/FrameState-inl.h
@@ -184,10 +184,19 @@ FrameState::push(Address address)
     /* :XXX: X64 */
     fe->resetUnsynced();
 
+    /* Prevent us from clobbering this reg. */
+    bool free = freeRegs.hasReg(address.base);
+    if (free)
+        freeRegs.takeReg(address.base);
+
     RegisterID reg = alloc(fe, RematInfo::DATA, true);
     masm.loadData32(address, reg);
     fe->data.setRegister(reg);
-    
+
+    /* Now it's safe to grab this register again. */
+    if (free)
+        freeRegs.putReg(address.base);
+
     reg = alloc(fe, RematInfo::TYPE, true);
     masm.loadTypeTag(address, reg);
     fe->type.setRegister(reg);
diff --git a/js/src/methodjit/FrameState.cpp b/js/src/methodjit/FrameState.cpp
index 4ab3ce2bcfd..2a4fd69c138 100644
--- a/js/src/methodjit/FrameState.cpp
+++ b/js/src/methodjit/FrameState.cpp
@@ -120,6 +120,9 @@ FrameState::storeTo(FrameEntry *fe, Address address, bool popped)
         return;
     }
 
+    /* Cannot clobber the address's register. */
+    JS_ASSERT(!freeRegs.hasReg(address.base));
+
     if (fe->data.inRegister()) {
         masm.storeData32(fe->data.reg(), addressOf(fe));
     } else {