Change value encoding scheme to make space for larger pointers

On android and on some other platforms, the upper bits of a pointer are
significant. We need to store them in our JS value encoding. Shift the
bits around to make this happen.

We now can store pointers of up to 57 bits. That's enough for everything
we've seen so far.

Fixes: QTBUG-101686
Fixes: QTBUG-91150
Pick-to: 6.5
Change-Id: I72e0fe63b27fca94840f82963e4d3936b3581b28
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Sami Shalayel <sami.shalayel@qt.io>
Reviewed-by: Ville Voutilainen <ville.voutilainen@qt.io>

1 files changed, 23 insertions, 12 deletions

diff --git a/src/qml/jit/qv4baselineassembler.cpp b/src/qml/jit/qv4baselineassembler.cpp
index 6f6877ec52..b97126945e 100644
--- a/src/qml/jit/qv4baselineassembler.cpp
+++ b/src/qml/jit/qv4baselineassembler.cpp
@@ -146,7 +146,9 @@ public:
     void toBoolean(std::function<void(RegisterID)> continuation)
     {
         urshift64(AccumulatorRegister, TrustedImm32(Value::IsIntegerConvertible_Shift), ScratchRegister);
-        auto needsConversion = branch32(NotEqual, TrustedImm32(1), ScratchRegister);
+        auto needsConversion = branch32(
+                    NotEqual, TrustedImm32(Value::IsIntegerConvertible_Value), ScratchRegister);
+
         continuation(AccumulatorRegister);
         Jump done = jump();
 
@@ -164,8 +166,10 @@ public:
 
     void toNumber()
     {
-        urshift64(AccumulatorRegister, TrustedImm32(Value::QuickType_Shift), ScratchRegister);
-        auto isNumber = branch32(GreaterThanOrEqual, ScratchRegister, TrustedImm32(Value::QT_Int));
+        move(TrustedImm64(Value::NumberMask), ScratchRegister);
+        and64(AccumulatorRegister, ScratchRegister);
+        move(TrustedImm64(Value::NumberDiscriminator), ScratchRegister2);
+        auto isNumber = branch64(GreaterThanOrEqual, ScratchRegister, ScratchRegister2);
 
         move(AccumulatorRegister, registerForArg(0));
         callHelper(toNumberHelper);
@@ -232,7 +236,8 @@ public:
     void isNullOrUndefined()
     {
         move(AccumulatorRegister, ScratchRegister);
-        compare64(Equal, ScratchRegister, TrustedImm32(0), AccumulatorRegister);
+        move(TrustedImm64(Value::ManagedMask), ScratchRegister2);
+        compare64(Equal, ScratchRegister, ScratchRegister2, AccumulatorRegister);
         Jump isUndef = branch32(NotEqual, TrustedImm32(0), AccumulatorRegister);
 
         // not undefined
@@ -246,7 +251,7 @@ public:
     Jump isIntOrBool()
     {
         urshift64(AccumulatorRegister, TrustedImm32(Value::IsIntegerOrBool_Shift), ScratchRegister);
-        return branch32(Equal, TrustedImm32(3), ScratchRegister);
+        return branch32(Equal, TrustedImm32(Value::IsIntegerOrBool_Value), ScratchRegister);
     }
 
     void jumpStrictEqualStackSlotInt(int lhs, int rhs, int offset)
@@ -280,7 +285,7 @@ public:
     void encodeDoubleIntoAccumulator(FPRegisterID src)
     {
         moveDoubleTo64(src, AccumulatorRegister);
-        move(TrustedImm64(Value::NaNEncodeMask), ScratchRegister);
+        move(TrustedImm64(Value::EncodeMask), ScratchRegister);
         xor64(ScratchRegister, AccumulatorRegister);
     }
 
@@ -319,7 +324,8 @@ public:
     Jump unopIntPath(std::function<Jump(void)> fastPath)
     {
         urshift64(AccumulatorRegister, TrustedImm32(Value::IsIntegerConvertible_Shift), ScratchRegister);
-        Jump accNotIntConvertible = branch32(NotEqual, TrustedImm32(1), ScratchRegister);
+        Jump accNotIntConvertible = branch32(
+                    NotEqual, TrustedImm32(Value::IsIntegerConvertible_Value), ScratchRegister);
 
         // both integer
         Jump failure = fastPath();
@@ -449,8 +455,12 @@ public:
 
     void toNumber()
     {
-        urshift32(AccumulatorRegisterTag, TrustedImm32(Value::QuickType_Shift - 32), ScratchRegister);
-        auto isNumber = branch32(GreaterThanOrEqual, ScratchRegister, TrustedImm32(Value::QT_Int));
+        and32(TrustedImm32(Value::NumberMask >> Value::Tag_Shift),
+              AccumulatorRegisterTag, ScratchRegister);
+        auto isNumber = branch32(
+                    GreaterThanOrEqual, ScratchRegister,
+                    TrustedImm32(Value::NumberDiscriminator >> Value::Tag_Shift));
+
 
         if (ArgInRegCount < 2) {
             subPtr(TrustedImm32(2 * PointerSize), StackPointerRegister); // stack alignment
@@ -599,7 +609,7 @@ public:
     Jump isIntOrBool()
     {
         urshift32(AccumulatorRegisterTag, TrustedImm32(Value::IsIntegerOrBool_Shift - 32), ScratchRegister);
-        return branch32(Equal, TrustedImm32(3), ScratchRegister);
+        return branch32(Equal, TrustedImm32(Value::IsIntegerOrBool_Value), ScratchRegister);
     }
 
     void pushValue(ReturnedValue v)
@@ -630,7 +640,8 @@ public:
     {
         urshift32(AccumulatorRegisterTag, TrustedImm32(Value::IsIntegerConvertible_Shift - 32),
                   ScratchRegister);
-        auto needsConversion = branch32(NotEqual, TrustedImm32(1), ScratchRegister);
+        auto needsConversion = branch32(
+                    NotEqual, TrustedImm32(Value::IsIntegerConvertible_Value), ScratchRegister);
         continuation(AccumulatorRegisterValue);
         Jump done = jump();
 
@@ -707,7 +718,7 @@ public:
     void encodeDoubleIntoAccumulator(FPRegisterID src)
     {
         moveDoubleToInts(src, AccumulatorRegisterValue, AccumulatorRegisterTag);
-        xor32(TrustedImm32(Value::NaNEncodeMask >> 32), AccumulatorRegisterTag);
+        xor32(TrustedImm32(Value::EncodeMask >> 32), AccumulatorRegisterTag);
     }
 
     void pushValueAligned(ReturnedValue v)