Bug 1112164 part 6 - RegisterSets: takeAny should take one register and all aliases of it. r=mjrosenb

js/src/asmjs/AsmJSValidate.cpp

@@ -8181,12 +8181,14 @@ StackDecrementForCall(MacroAssembler &masm, uint32_t alignment, const VectorT &a
 }
 
 #if defined(JS_CODEGEN_ARM)
-// The ARM system ABI also includes d15 in the non volatile float registers.
+// The ARM system ABI also includes d15 & s31 in the non volatile float registers.
 // Also exclude lr (a.k.a. r14) as we preserve it manually)
 static const RegisterSet NonVolatileRegs =
     RegisterSet(GeneralRegisterSet(Registers::NonVolatileMask &
                                    ~(uint32_t(1) << Registers::lr)),
-                FloatRegisterSet(FloatRegisters::NonVolatileMask | (1ULL << FloatRegisters::d15)));
+                FloatRegisterSet(FloatRegisters::NonVolatileMask
+                                 | (1ULL << FloatRegisters::d15)
+                                 | (1ULL << FloatRegisters::s31)));
 #else
 static const RegisterSet NonVolatileRegs =
     RegisterSet(GeneralRegisterSet(Registers::NonVolatileMask),

js/src/jit/BacktrackingAllocator.cpp

@@ -17,11 +17,11 @@ BacktrackingAllocator::init()
 {
     RegisterSet remainingRegisters(allRegisters_);
     while (!remainingRegisters.empty(/* float = */ false)) {
-        AnyRegister reg = AnyRegister(remainingRegisters.takeGeneral());
+        AnyRegister reg = AnyRegister(remainingRegisters.takeUnaliasedGeneral());
         registers[reg.code()].allocatable = true;
     }
     while (!remainingRegisters.empty(/* float = */ true)) {
-        AnyRegister reg = AnyRegister(remainingRegisters.takeFloat());
+        AnyRegister reg = AnyRegister(remainingRegisters.takeUnaliasedFloat());
         registers[reg.code()].allocatable = true;
     }
 

js/src/jit/LinearScan.cpp

@@ -998,7 +998,7 @@ LinearScanAllocator::findBestFreeRegister(CodePosition *freeUntil)
     for (RegisterSet regs(allRegisters_); !regs.empty(needFloat); ) {
         // If the requested register is a FP, we may need to look at
         // all of the float32 and float64 registers.
-        AnyRegister reg = regs.takeAny(needFloat);
+        AnyRegister reg = regs.takeUnaliasedAny(needFloat);
         freeUntilPos[reg.code()] = CodePosition::MAX;
     }
     for (IntervalIterator i(active.begin()); i != active.end(); i++) {
@@ -1126,7 +1126,7 @@ LinearScanAllocator::findBestBlockedRegister(CodePosition *nextUsed)
     CodePosition nextUsePos[AnyRegister::Total];
     bool needFloat = vregs[current->vreg()].isFloatReg();
     for (RegisterSet regs(allRegisters_); !regs.empty(needFloat); ) {
-        AnyRegister reg = regs.takeAny(needFloat);
+        AnyRegister reg = regs.takeUnaliasedAny(needFloat);
         nextUsePos[reg.code()] = CodePosition::MAX;
     }
     for (IntervalIterator i(active.begin()); i != active.end(); i++) {

js/src/jit/RegisterSets.h

@@ -425,7 +425,7 @@ class TypedRegisterSet
         for (uint32_t a = 0; a < reg.numAliased(); a++) {
             T tmp;
             reg.aliased(a, &tmp);
-            bits_ &= ~(SetType(1) << tmp.code());
+            takeUnchecked(tmp);
         }
     }
     void take(ValueOperand value) {
@@ -488,12 +488,19 @@ class TypedRegisterSet
     T takeAny() {
         MOZ_ASSERT(!empty());
         T reg = getAny();
-        take(reg);
+        takeAllAliasedUnchecked(reg);
+        return reg;
+    }
+    T takeUnaliasedAny() {
+        // This variant is used by LinearScan for iterating over all registers.
+        MOZ_ASSERT(!empty());
+        T reg = getAny();
+        takeUnchecked(reg);
         return reg;
     }
     T takeAnyExcluding(T preclude) {
         T reg = getAnyExcluding(preclude);
-        take(reg);
+        takeAllAliasedUnchecked(reg);
         return reg;
     }
     ValueOperand takeAnyValue() {
@@ -509,15 +516,20 @@ class TypedRegisterSet
 #endif
     }
     T takeFirst() {
+        // This function is used to implement a forward register set iterator.
         MOZ_ASSERT(!empty());
         T reg = getFirst();
-        take(reg);
+        // The iterator is used by PushRegsInMask which might be called with
+        // AllAlllocatableRegister mask.  To avoid saving more than needed we
+        // should take aliased registers too.
+        takeAllAliasedUnchecked(reg);
         return reg;
     }
     T takeLast() {
+        // This function is used to implement a backward register set iterator.
         MOZ_ASSERT(!empty());
         T reg = getLast();
-        take(reg);
+        takeAllAliasedUnchecked(reg);
         return reg;
     }
     void clear() {
@@ -646,9 +658,15 @@ class RegisterSet {
     FloatRegister takeFloat() {
         return fpu_.takeAny();
     }
+    FloatRegister takeUnaliasedFloat() {
+        return fpu_.takeUnaliasedAny();
+    }
     Register takeGeneral() {
         return gpr_.takeAny();
     }
+    Register takeUnaliasedGeneral() {
+        return gpr_.takeUnaliasedAny();
+    }
     ValueOperand takeValueOperand() {
 #if defined(JS_NUNBOX32)
         return ValueOperand(takeGeneral(), takeGeneral());
@@ -670,10 +688,11 @@ class RegisterSet {
         else
             gpr_.takeAllAliasedUnchecked(reg.gpr());
     }
-    AnyRegister takeAny(bool isFloat) {
+    // This function is used by LinearScan to find a free register.
+    AnyRegister takeUnaliasedAny(bool isFloat) {
         if (isFloat)
-            return AnyRegister(takeFloat());
-        return AnyRegister(takeGeneral());
+            return AnyRegister(takeUnaliasedFloat());
+        return AnyRegister(takeUnaliasedGeneral());
     }
     void clear() {
         gpr_.clear();