Remove stack alignments of OOL VM calls. (Bug 743094 part 1, r=dvander)

js/src/ion/IonMacroAssembler.cpp

@@ -114,19 +114,16 @@ MacroAssembler::PushRegsInMask(RegisterSet set)
     }
     // It has been decreed that the stack shall always be 8 byte aligned on ARM.
     // maintain this invariant.  It can't hurt other platforms.
-    size_t new_diff = (diff + 7) & ~7;
-    reserveStack(new_diff);
+    reserveStack(diff);
 
-    diff = new_diff - diff;
-    for (AnyRegisterIterator iter(set); iter.more(); iter++) {
-        AnyRegister reg = *iter;
-        if (reg.isFloat()) {
-            storeDouble(reg.fpu(), Address(StackPointer, diff));
-            diff += sizeof(double);
-        } else {
-            storePtr(reg.gpr(), Address(StackPointer, diff));
-            diff += STACK_SLOT_SIZE;
-        }
+    diff = 0;
+    for (GeneralRegisterIterator iter(set.gprs()); iter.more(); iter++) {
+        storePtr(*iter, Address(StackPointer, diff));
+        diff += STACK_SLOT_SIZE;
+    }
+    for (FloatRegisterIterator iter(set.fpus()); iter.more(); iter++) {
+        storeDouble(*iter, Address(StackPointer, diff));
+        diff += sizeof(double);
     }
 }
 
@@ -134,28 +131,16 @@ void
 MacroAssembler::PopRegsInMask(RegisterSet set)
 {
     size_t diff = 0;
-    // Undo the alignment that was done in PushRegsInMask.
-    for (AnyRegisterIterator iter(set); iter.more(); iter++) {
-        AnyRegister reg = *iter;
-        if (reg.isFloat())
-            diff += sizeof(double);
-        else
-            diff += STACK_SLOT_SIZE;
+    for (GeneralRegisterIterator iter(set.gprs()); iter.more(); iter++) {
+        loadPtr(Address(StackPointer, diff), *iter);
+        diff += STACK_SLOT_SIZE;
+    }
+    for (FloatRegisterIterator iter(set.fpus()); iter.more(); iter++) {
+        loadDouble(Address(StackPointer, diff), *iter);
+        diff += sizeof(double);
     }
-    size_t new_diff = (diff + 7) & ~7;
 
-    diff = new_diff - diff;
-    for (AnyRegisterIterator iter(set); iter.more(); iter++) {
-        AnyRegister reg = *iter;
-        if (reg.isFloat()) {
-            loadDouble(Address(StackPointer, diff), reg.fpu());
-            diff += sizeof(double);
-        } else {
-            loadPtr(Address(StackPointer, diff), reg.gpr());
-            diff += STACK_SLOT_SIZE;
-        }
-    }
-    freeStack(new_diff);
+    freeStack(diff);
 }
 
 void

js/src/ion/arm/Architecture-arm.h

@@ -143,7 +143,7 @@ class Registers
 
     static const uint32 WrapperMask =
         VolatileMask |         // = arguments
-        (1 << Registers::r4) | // = Invalidation saved PC
+        (1 << Registers::r4) | // = outReg
         (1 << Registers::r5);  // = argBase
 
     static const uint32 SingleByteRegs =

js/src/ion/arm/MacroAssembler-arm.cpp

@@ -1325,7 +1325,8 @@ MacroAssemblerARMCompat::callWithExitFrame(IonCode *target)
 
     addPendingJump(m_buffer.nextOffset(), target->raw(), Relocation::IONCODE);
     ma_mov(Imm32((int) target->raw()), ScratchRegister);
-    callIon(ScratchRegister);
+    adjustFrame(sizeof(void*));
+    ma_callIon(ScratchRegister);
 }
 
 void
@@ -2648,7 +2649,7 @@ MacroAssemblerARMCompat::handleException()
     ma_mov(sp, r0);
 
     // Ask for an exception handler.
-    setupAlignedABICall(1);
+    setupUnalignedABICall(1, r1);
     passABIArg(r0);
     callWithABI(JS_FUNC_TO_DATA_PTR(void *, ion::HandleException));
     // Load the error value, load the new stack pointer, and return.

js/src/ion/arm/Trampoline-arm.cpp

@@ -575,7 +575,6 @@ IonCompartment::generateVMWrapper(JSContext *cx, const VMFunction &f)
 
     // Save the base of the argument set stored on the stack.
     Register argsBase = InvalidReg;
-    uint32 argumentPadding = (f.explicitStackSlots() * sizeof(void *)) % StackAlignment;
     if (f.explicitArgs) {
         argsBase = r5;
         regs.take(argsBase);
@@ -586,13 +585,15 @@ IonCompartment::generateVMWrapper(JSContext *cx, const VMFunction &f)
     Register outReg = InvalidReg;
     switch (f.outParam) {
       case Type_Value:
-        outReg = regs.takeAny();
+        outReg = r4;
+        regs.take(outReg);
         masm.reserveStack(sizeof(Value));
         masm.ma_mov(sp, outReg);
         break;
 
       case Type_Int32:
-        outReg = regs.takeAny();
+        outReg = r4;
+        regs.take(outReg);
         masm.reserveStack(sizeof(int32));
         masm.ma_mov(sp, outReg);
         break;
@@ -602,8 +603,8 @@ IonCompartment::generateVMWrapper(JSContext *cx, const VMFunction &f)
         break;
     }
 
-    // ARM stack is made to be constantly aligned by 8.
-    masm.setupAlignedABICall(f.argc());
+    Register temp = regs.getAny();
+    masm.setupUnalignedABICall(f.argc(), temp);
 
     // Initialize and set the context parameter.
     // r0 is the first argument register.
@@ -670,8 +671,7 @@ IonCompartment::generateVMWrapper(JSContext *cx, const VMFunction &f)
         break;
     }
     masm.freeStack(sizeof(IonCode *));
-    masm.retn(Imm32(sizeof(IonExitFrameLayout) + argumentPadding +
-                    f.explicitStackSlots() * sizeof(void *)));
+    masm.retn(Imm32(sizeof(IonExitFrameLayout) + f.explicitStackSlots() * sizeof(void *)));
 
     masm.bind(&exception);
     masm.handleException();

js/src/ion/shared/CodeGenerator-shared.cpp

@@ -379,14 +379,6 @@ CodeGeneratorShared::callVM(const VMFunction &fun, LInstruction *ins)
     if (!wrapper)
         return false;
 
-    uint32 argumentPadding = 0;
-    if (StackKeptAligned) {
-        // We add an extra padding after the pushed arguments if we pushed an
-        // odd number of arguments. This padding is removed by the wrapper when
-        // it returns.
-        argumentPadding = (fun.explicitStackSlots() * sizeof(void *)) % StackAlignment;
-        masm.reserveStack(argumentPadding);
-    }
     // Call the wrapper function.  The wrapper is in charge to unwind the stack
     // when returning from the call.  Failures are handled with exceptions based
     // on the return value of the C functions.  To guard the outcome of the
@@ -400,7 +392,7 @@ CodeGeneratorShared::callVM(const VMFunction &fun, LInstruction *ins)
     int framePop = sizeof(IonExitFrameLayout) - sizeof(void*);
 
     // Pop arguments from framePushed.
-    masm.implicitPop(fun.explicitStackSlots() * sizeof(void *) + argumentPadding + framePop);
+    masm.implicitPop(fun.explicitStackSlots() * sizeof(void *) + framePop);
 
     // Stack is:
     //    ... frame ...

js/src/ion/x64/Trampoline-x64.cpp

@@ -480,7 +480,7 @@ IonCompartment::generateVMWrapper(JSContext *cx, const VMFunction &f)
     Register argsBase = InvalidReg;
     if (f.explicitArgs) {
         argsBase = r10;
-        regs.take(r10);
+        regs.take(argsBase);
         masm.lea(Operand(rsp,IonExitFrameLayout::SizeWithFooter()), argsBase);
     }
 
@@ -510,7 +510,6 @@ IonCompartment::generateVMWrapper(JSContext *cx, const VMFunction &f)
     // Initialize the context parameter.
     Register cxreg = IntArgReg0;
     masm.loadJSContext(cxreg);
-
     masm.passABIArg(cxreg);
 
     size_t argDisp = 0;