Add constant blinding/pooling option for X8632 code translation

src/IceTargetLoweringX8632.cpp

Index: src/IceTargetLoweringX8632.cpp
diff --git a/src/IceTargetLoweringX8632.cpp b/src/IceTargetLoweringX8632.cpp
index 506b315079909210d3b1f7c9dc1fbee21e0e53ea..af460cb06767e35512d7c2e7e57f5ed108dc466d 100644
--- a/src/IceTargetLoweringX8632.cpp
+++ b/src/IceTargetLoweringX8632.cpp
@@ -246,6 +246,25 @@ ICETYPE_TABLE
 #undef X
 } // end of namespace dummy3
 
+// A helper class to ease the settings of RandomizationPoolingPause
+// to disable constant blinding or pooling for some translation phases.
+class BoolFlagSaver {
+  BoolFlagSaver() = delete;
+  BoolFlagSaver(const BoolFlagSaver &) = delete;
+  BoolFlagSaver &operator=(const BoolFlagSaver &) = delete;
+
+public:
+  BoolFlagSaver(bool &F, bool NewValue) : Flag(F) {
+    OldValue = F;
+    F = NewValue;
+  }
+  ~BoolFlagSaver() { Flag = OldValue; }
+
+private:
+  bool &Flag;

[Jim Stichnoth, 2015/06/19 16:51:03]

Can you do this?

  bool &const Flag;
  const bool OldValue;

and initialize OldValue in the ctor initializer list?

[qining, 2015/06/19 20:22:25]

I can initialize OldValue in the initialization list. Is this possible to do
:bool& const Flag? My compiler complain about that, and I think Flag should not
be a constant, as we will need to assign it in the destructor.

[Jim Stichnoth, 2015/06/19 23:12:15]

I think I was wrong about const and Flag, sorry.

+  bool OldValue;
+};
+
 } // end of anonymous namespace
 
 BoolFoldingEntry::BoolFoldingEntry(Inst *I)
@@ -399,8 +418,8 @@ TargetX8632::TargetX8632(Cfg *Func)
       InstructionSet(static_cast<X86InstructionSet>(
           Func->getContext()->getFlags().getTargetInstructionSet() -
           TargetInstructionSet::X86InstructionSet_Begin)),
-      IsEbpBasedFrame(false), NeedsStackAlignment(false),
-      SpillAreaSizeBytes(0) {
+      IsEbpBasedFrame(false), NeedsStackAlignment(false), SpillAreaSizeBytes(0),
+      RandomizationPoolingPaused(false) {
   static_assert((X86InstructionSet::End - X86InstructionSet::Begin) ==
                     (TargetInstructionSet::X86InstructionSet_End -
                      TargetInstructionSet::X86InstructionSet_Begin),
@@ -482,7 +501,11 @@ void TargetX8632::translateO2() {
     return;
   Func->dump("After x86 address mode opt");
 
-  doLoadOpt();
+  // qining: disable constant blinding or pooling for load optimization
+  {
+    BoolFlagSaver B(RandomizationPoolingPaused, true);
+    doLoadOpt();
+  }
   Func->genCode();
   if (Func->hasError())
     return;
@@ -509,7 +532,13 @@ void TargetX8632::translateO2() {
   Func->dump("After linear scan regalloc");
 
   if (Ctx->getFlags().getPhiEdgeSplit()) {
-    Func->advancedPhiLowering();
+    // qining: In general we need to pause constant blinding or pooling

[Jim Stichnoth, 2015/06/19 16:51:03]

Don't tag comments with your name.  Use TODO(qining): or TODO(qining,stichnot)
or omit it.

[qining, 2015/06/19 20:22:26]

Done.

+    // during advanced phi lowering, unless the lowering assignment has a
+    // physical register for the Dest Variable
+    {
+      BoolFlagSaver B(RandomizationPoolingPaused, true);
+      Func->advancedPhiLowering();
+    }
     Func->dump("After advanced Phi lowering");
   }
 
@@ -762,8 +791,9 @@ void TargetX8632::emitVariable(const Variable *Var) const {
     Str << "%" << getRegName(Var->getRegNum(), Var->getType());
     return;
   }
-  if (Var->getWeight().isInf())
+  if (Var->getWeight().isInf()) {
     llvm_unreachable("Infinite-weight Variable has no register assigned");
+  }
   int32_t Offset = Var->getStackOffset();
   if (!hasFramePointer())
     Offset += getStackAdjustment();
@@ -776,8 +806,9 @@ void TargetX8632::emitVariable(const Variable *Var) const {
 X8632::Address TargetX8632::stackVarToAsmOperand(const Variable *Var) const {
   if (Var->hasReg())
     llvm_unreachable("Stack Variable has a register assigned");
-  if (Var->getWeight().isInf())
+  if (Var->getWeight().isInf()) {
     llvm_unreachable("Infinite-weight Variable has no register assigned");
+  }
   int32_t Offset = Var->getStackOffset();
   if (!hasFramePointer())
     Offset += getStackAdjustment();
@@ -1168,12 +1199,18 @@ Operand *TargetX8632::loOperand(Operand *Operand) {
     return Var->getLo();
   }
   if (ConstantInteger64 *Const = llvm::dyn_cast<ConstantInteger64>(Operand)) {
-    return Ctx->getConstantInt32(static_cast<uint32_t>(Const->getValue()));
-  }
-  if (OperandX8632Mem *Mem = llvm::dyn_cast<OperandX8632Mem>(Operand)) {
-    return OperandX8632Mem::create(Func, IceType_i32, Mem->getBase(),
-                                   Mem->getOffset(), Mem->getIndex(),
-                                   Mem->getShift(), Mem->getSegmentRegister());
+    ConstantInteger32 *ConstInt = llvm::dyn_cast<ConstantInteger32>(
+        Ctx->getConstantInt32(static_cast<int32_t>(Const->getValue())));
+    return legalize(ConstInt);
+  }
+  if (OperandX8632Mem *Mem = llvm::cast<OperandX8632Mem>(Operand)) {

[Jim Stichnoth, 2015/06/19 16:51:03]

llvm::dyn_cast

[qining, 2015/06/19 20:22:25]

Done.

+    OperandX8632Mem *MemOperand = OperandX8632Mem::create(
+        Func, IceType_i32, Mem->getBase(), Mem->getOffset(), Mem->getIndex(),
+        Mem->getShift(), Mem->getSegmentRegister());
+    // Test if we should randomize or pool the offset, if so randomize it or
+    // pool it then create mem operand with the blinded/pooled constant.
+    // Otherwise, return the mem operand as ordinary mem operand.
+    return legalize(MemOperand);
   }
   llvm_unreachable("Unsupported operand type");
   return nullptr;
@@ -1189,8 +1226,10 @@ Operand *TargetX8632::hiOperand(Operand *Operand) {
     return Var->getHi();
   }
   if (ConstantInteger64 *Const = llvm::dyn_cast<ConstantInteger64>(Operand)) {
-    return Ctx->getConstantInt32(
-        static_cast<uint32_t>(Const->getValue() >> 32));
+    ConstantInteger32 *ConstInt = llvm::dyn_cast<ConstantInteger32>(
+        Ctx->getConstantInt32(static_cast<int32_t>(Const->getValue() >> 32)));
+    // check if we need to blind/pool the constant
+    return legalize(ConstInt);
   }
   if (OperandX8632Mem *Mem = llvm::dyn_cast<OperandX8632Mem>(Operand)) {
     Constant *Offset = Mem->getOffset();
@@ -1206,9 +1245,13 @@ Operand *TargetX8632::hiOperand(Operand *Operand) {
           Ctx->getConstantSym(4 + SymOffset->getOffset(), SymOffset->getName(),
                               SymOffset->getSuppressMangling());
     }
-    return OperandX8632Mem::create(Func, IceType_i32, Mem->getBase(), Offset,
-                                   Mem->getIndex(), Mem->getShift(),
-                                   Mem->getSegmentRegister());
+    OperandX8632Mem *MemOperand = OperandX8632Mem::create(
+        Func, IceType_i32, Mem->getBase(), Offset, Mem->getIndex(),
+        Mem->getShift(), Mem->getSegmentRegister());
+    // Test if the Offset is an eligible i32 constants for randomization and
+    // pooling. Blind/pool it if it is. Otherwise return as oridinary mem
+    // operand.
+    return legalize(MemOperand);
   }
   llvm_unreachable("Unsupported operand type");
   return nullptr;
@@ -1287,6 +1330,102 @@ void TargetX8632::lowerAlloca(const InstAlloca *Inst) {
   _mov(Dest, esp);
 }
 
+// Strength-reduce scalar integer multiplication by a constant (for
+// i32 or narrower) for certain constants.  The lea instruction can be
+// used to multiply by 3, 5, or 9, and the lsh instruction can be used
+// to multiply by powers of 2.  These can be combined such that
+// e.g. multiplying by 100 can be done as 2 lea-based multiplies by 5,
+// combined with left-shifting by 2.
+bool TargetX8632::optimizeScalarMul(Variable *Dest, Operand *Src0,
+                                    int32_t Src1) {
+  // Disable this optimization for Om1 and O0, just to keep things
+  // simple there.
+  if (Ctx->getFlags().getOptLevel() < Opt_1)
+    return false;
+  Type Ty = Dest->getType();
+  Variable *T = nullptr;
+  if (Src1 == -1) {
+    _mov(T, Src0);
+    _neg(T);
+    _mov(Dest, T);
+    return true;
+  }
+  if (Src1 == 0) {
+    _mov(Dest, Ctx->getConstantZero(Ty));
+    return true;
+  }
+  if (Src1 == 1) {
+    _mov(T, Src0);
+    _mov(Dest, T);
+    return true;
+  }
+  // Don't bother with the edge case where Src1 == MININT.
+  if (Src1 == -Src1)
+    return false;
+  const bool Src1IsNegative = Src1 < 0;
+  if (Src1IsNegative)
+    Src1 = -Src1;
+  uint32_t Count9 = 0;
+  uint32_t Count5 = 0;
+  uint32_t Count3 = 0;
+  uint32_t Count2 = 0;
+  uint32_t CountOps = 0;
+  while (Src1 > 1) {
+    if (Src1 % 9 == 0) {
+      ++CountOps;
+      ++Count9;
+      Src1 /= 9;
+    } else if (Src1 % 5 == 0) {
+      ++CountOps;
+      ++Count5;
+      Src1 /= 5;
+    } else if (Src1 % 3 == 0) {
+      ++CountOps;
+      ++Count3;
+      Src1 /= 3;
+    } else if (Src1 % 2 == 0) {
+      if (Count2 == 0)
+        ++CountOps;
+      ++Count2;
+      Src1 /= 2;
+    } else {
+      return false;
+    }
+  }
+  // Lea optimization only works for i16 and i32 types, not i8.
+  if (Ty != IceType_i16 && Ty != IceType_i32 && (Count3 || Count5 || Count9))
+    return false;
+  // Limit the number of lea/shl operations for a single multiply, to
+  // a somewhat arbitrary choice of 3.
+  const uint32_t MaxOpsForOptimizedMul = 3;
+  if (CountOps > MaxOpsForOptimizedMul)
+    return false;
+  _mov(T, Src0);
+  Constant *Zero = Ctx->getConstantZero(IceType_i32);
+  for (uint32_t i = 0; i < Count9; ++i) {
+    const uint16_t Shift = 3; // log2(9-1)
+    _lea(T, OperandX8632Mem::create(Func, IceType_void, T, Zero, T, Shift));
+    _set_dest_nonkillable();
+  }
+  for (uint32_t i = 0; i < Count5; ++i) {
+    const uint16_t Shift = 2; // log2(5-1)
+    _lea(T, OperandX8632Mem::create(Func, IceType_void, T, Zero, T, Shift));
+    _set_dest_nonkillable();
+  }
+  for (uint32_t i = 0; i < Count3; ++i) {
+    const uint16_t Shift = 1; // log2(3-1)
+    _lea(T, OperandX8632Mem::create(Func, IceType_void, T, Zero, T, Shift));
+    _set_dest_nonkillable();
+  }
+  if (Count2) {
+    _shl(T, Ctx->getConstantInt(Ty, Count2));
+  }
+  if (Src1IsNegative)
+    _neg(T);
+  _mov(Dest, T);
+  return true;
+}
+
 void TargetX8632::lowerArithmetic(const InstArithmetic *Inst) {
   Variable *Dest = Inst->getDest();
   Operand *Src0 = legalize(Inst->getSrc(0));
@@ -1294,8 +1433,47 @@ void TargetX8632::lowerArithmetic(const InstArithmetic *Inst) {
   if (Inst->isCommutative()) {
     if (!llvm::isa<Variable>(Src0) && llvm::isa<Variable>(Src1))
       std::swap(Src0, Src1);
+    if (llvm::isa<Constant>(Src0) && !llvm::isa<Constant>(Src1))
+      std::swap(Src0, Src1);
   }
   if (Dest->getType() == IceType_i64) {
+    switch (Inst->getOp()) {

[Jim Stichnoth, 2015/06/19 16:51:03]

Add a comment explaining why these instructions are being lowered in a separate
switch statement from below.  (I really don't like having to do this, but so far
I haven't thought of a better solution.)

[qining, 2015/06/19 20:22:26]

Done.

+    case InstArithmetic::Udiv: {
+      const SizeT MaxSrcs = 2;
+      InstCall *Call = makeHelperCall(H_udiv_i64, Dest, MaxSrcs);
+      Call->addArg(Inst->getSrc(0));
+      Call->addArg(Inst->getSrc(1));
+      lowerCall(Call);
+      return;
+    }
+    case InstArithmetic::Sdiv: {
+      const SizeT MaxSrcs = 2;
+      InstCall *Call = makeHelperCall(H_sdiv_i64, Dest, MaxSrcs);
+      Call->addArg(Inst->getSrc(0));
+      Call->addArg(Inst->getSrc(1));
+      lowerCall(Call);
+      return;
+    }
+    case InstArithmetic::Urem: {
+      const SizeT MaxSrcs = 2;
+      InstCall *Call = makeHelperCall(H_urem_i64, Dest, MaxSrcs);
+      Call->addArg(Inst->getSrc(0));
+      Call->addArg(Inst->getSrc(1));
+      lowerCall(Call);
+      return;
+    }
+    case InstArithmetic::Srem: {
+      const SizeT MaxSrcs = 2;
+      InstCall *Call = makeHelperCall(H_srem_i64, Dest, MaxSrcs);
+      Call->addArg(Inst->getSrc(0));
+      Call->addArg(Inst->getSrc(1));
+      lowerCall(Call);
+      return;
+    }
+    default:
+      break;
+    }
+
     Variable *DestLo = llvm::cast<Variable>(loOperand(Dest));
     Variable *DestHi = llvm::cast<Variable>(hiOperand(Dest));
     Operand *Src0Lo = loOperand(Src0);
@@ -1485,34 +1663,6 @@ void TargetX8632::lowerArithmetic(const InstArithmetic *Inst) {
       _mov(DestLo, T_2);
       _mov(DestHi, T_3);
     } break;
-    case InstArithmetic::Udiv: {
-      const SizeT MaxSrcs = 2;
-      InstCall *Call = makeHelperCall(H_udiv_i64, Dest, MaxSrcs);
-      Call->addArg(Inst->getSrc(0));
-      Call->addArg(Inst->getSrc(1));
-      lowerCall(Call);
-    } break;
-    case InstArithmetic::Sdiv: {
-      const SizeT MaxSrcs = 2;
-      InstCall *Call = makeHelperCall(H_sdiv_i64, Dest, MaxSrcs);
-      Call->addArg(Inst->getSrc(0));
-      Call->addArg(Inst->getSrc(1));
-      lowerCall(Call);
-    } break;
-    case InstArithmetic::Urem: {
-      const SizeT MaxSrcs = 2;
-      InstCall *Call = makeHelperCall(H_urem_i64, Dest, MaxSrcs);
-      Call->addArg(Inst->getSrc(0));
-      Call->addArg(Inst->getSrc(1));
-      lowerCall(Call);
-    } break;
-    case InstArithmetic::Srem: {
-      const SizeT MaxSrcs = 2;
-      InstCall *Call = makeHelperCall(H_srem_i64, Dest, MaxSrcs);
-      Call->addArg(Inst->getSrc(0));
-      Call->addArg(Inst->getSrc(1));
-      lowerCall(Call);
-    } break;
     case InstArithmetic::Fadd:
     case InstArithmetic::Fsub:
     case InstArithmetic::Fmul:
@@ -1520,8 +1670,13 @@ void TargetX8632::lowerArithmetic(const InstArithmetic *Inst) {
     case InstArithmetic::Frem:
       llvm_unreachable("FP instruction with i64 type");
       break;
+    default:

[Jim Stichnoth, 2015/06/19 16:51:03]

Don't use default, instead just explicitly list Udiv/Sdiv/Urem/Srem.  That way,
if a new Arithmetic instruction is ever introduced, the compile will warn if we
forget to add its i64 lowering.

[qining, 2015/06/19 20:22:25]

Done.

+      llvm_unreachable("Unknown instruction with i64 type");
+      break;
     }
-  } else if (isVectorType(Dest->getType())) {
+    return;
+  }
+  if (isVectorType(Dest->getType())) {
     // TODO: Trap on integer divide and integer modulo by zero.
     // See: https://code.google.com/p/nativeclient/issues/detail?id=3899
     if (llvm::isa<OperandX8632Mem>(Src1))
@@ -1650,175 +1805,248 @@ void TargetX8632::lowerArithmetic(const InstArithmetic *Inst) {
       scalarizeArithmetic(Inst->getOp(), Dest, Src0, Src1);
       break;
     }
-  } else { // Dest->getType() is non-i64 scalar
-    Variable *T_edx = nullptr;
-    Variable *T = nullptr;
-    switch (Inst->getOp()) {
-    case InstArithmetic::_num:
-      llvm_unreachable("Unknown arithmetic operator");
-      break;
-    case InstArithmetic::Add:
-      _mov(T, Src0);
-      _add(T, Src1);
-      _mov(Dest, T);
-      break;
-    case InstArithmetic::And:
-      _mov(T, Src0);
-      _and(T, Src1);
-      _mov(Dest, T);
-      break;
-    case InstArithmetic::Or:
-      _mov(T, Src0);
-      _or(T, Src1);
-      _mov(Dest, T);
-      break;
-    case InstArithmetic::Xor:
+    return;
+  }
+  Variable *T_edx = nullptr;
+  Variable *T = nullptr;
+  switch (Inst->getOp()) {
+  case InstArithmetic::_num:
+    llvm_unreachable("Unknown arithmetic operator");
+    break;
+  case InstArithmetic::Add:
+    _mov(T, Src0);
+    _add(T, Src1);
+    _mov(Dest, T);
+    break;
+  case InstArithmetic::And:
+    _mov(T, Src0);
+    _and(T, Src1);
+    _mov(Dest, T);
+    break;
+  case InstArithmetic::Or:
+    _mov(T, Src0);
+    _or(T, Src1);
+    _mov(Dest, T);
+    break;
+  case InstArithmetic::Xor:
+    _mov(T, Src0);
+    _xor(T, Src1);
+    _mov(Dest, T);
+    break;
+  case InstArithmetic::Sub:
+    _mov(T, Src0);
+    _sub(T, Src1);
+    _mov(Dest, T);
+    break;
+  case InstArithmetic::Mul:
+    if (auto *C = llvm::dyn_cast<ConstantInteger32>(Src1)) {
+      if (optimizeScalarMul(Dest, Src0, C->getValue()))
+        return;
+    }
+    // The 8-bit version of imul only allows the form "imul r/m8"
+    // where T must be in eax.
+    if (isByteSizedArithType(Dest->getType())) {
+      _mov(T, Src0, RegX8632::Reg_eax);
+      Src1 = legalize(Src1, Legal_Reg | Legal_Mem);
+    } else {
       _mov(T, Src0);
-      _xor(T, Src1);
+    }
+    _imul(T, Src1);
+    _mov(Dest, T);
+    break;
+  case InstArithmetic::Shl:
+    _mov(T, Src0);
+    if (!llvm::isa<Constant>(Src1))
+      Src1 = legalizeToVar(Src1, RegX8632::Reg_ecx);
+    _shl(T, Src1);
+    _mov(Dest, T);
+    break;
+  case InstArithmetic::Lshr:
+    _mov(T, Src0);
+    if (!llvm::isa<Constant>(Src1))
+      Src1 = legalizeToVar(Src1, RegX8632::Reg_ecx);
+    _shr(T, Src1);
+    _mov(Dest, T);
+    break;
+  case InstArithmetic::Ashr:
+    _mov(T, Src0);
+    if (!llvm::isa<Constant>(Src1))
+      Src1 = legalizeToVar(Src1, RegX8632::Reg_ecx);
+    _sar(T, Src1);
+    _mov(Dest, T);
+    break;
+  case InstArithmetic::Udiv:
+    // div and idiv are the few arithmetic operators that do not allow
+    // immediates as the operand.
+    Src1 = legalize(Src1, Legal_Reg | Legal_Mem);
+    if (isByteSizedArithType(Dest->getType())) {
+      Variable *T_ah = nullptr;
+      Constant *Zero = Ctx->getConstantZero(IceType_i8);
+      _mov(T, Src0, RegX8632::Reg_eax);
+      _mov(T_ah, Zero, RegX8632::Reg_ah);
+      _div(T, Src1, T_ah);
       _mov(Dest, T);
-      break;
-    case InstArithmetic::Sub:
-      _mov(T, Src0);
-      _sub(T, Src1);
+    } else {
+      Constant *Zero = Ctx->getConstantZero(IceType_i32);
+      _mov(T, Src0, RegX8632::Reg_eax);
+      _mov(T_edx, Zero, RegX8632::Reg_edx);
+      _div(T, Src1, T_edx);
       _mov(Dest, T);
-      break;
-    case InstArithmetic::Mul:
-      // TODO: Optimize for llvm::isa<Constant>(Src1)
-      // TODO: Strength-reduce multiplications by a constant,
-      // particularly -1 and powers of 2.  Advanced: use lea to
-      // multiply by 3, 5, 9.
-      //
-      // The 8-bit version of imul only allows the form "imul r/m8"
-      // where T must be in eax.
-      if (isByteSizedArithType(Dest->getType())) {
-        _mov(T, Src0, RegX8632::Reg_eax);
-        Src1 = legalize(Src1, Legal_Reg | Legal_Mem);
-      } else {
-        _mov(T, Src0);
+    }
+    break;
+  case InstArithmetic::Sdiv:
+    // TODO(stichnot): Enable this after doing better performance
+    // and cross testing.
+    if (false && Ctx->getFlags().getOptLevel() >= Opt_1) {
+      // Optimize division by constant power of 2, but not for Om1
+      // or O0, just to keep things simple there.
+      if (auto *C = llvm::dyn_cast<ConstantInteger32>(Src1)) {
+        int32_t Divisor = C->getValue();
+        uint32_t UDivisor = static_cast<uint32_t>(Divisor);
+        if (Divisor > 0 && llvm::isPowerOf2_32(UDivisor)) {
+          uint32_t LogDiv = llvm::Log2_32(UDivisor);
+          Type Ty = Dest->getType();
+          // LLVM does the following for dest=src/(1<<log):
+          //   t=src
+          //   sar t,typewidth-1 // -1 if src is negative, 0 if not
+          //   shr t,typewidth-log
+          //   add t,src
+          //   sar t,log
+          //   dest=t
+          uint32_t TypeWidth = X86_CHAR_BIT * typeWidthInBytes(Ty);
+          _mov(T, Src0);
+          // If for some reason we are dividing by 1, just treat it
+          // like an assignment.
+          if (LogDiv > 0) {
+            // The initial sar is unnecessary when dividing by 2.
+            if (LogDiv > 1)
+              _sar(T, Ctx->getConstantInt(Ty, TypeWidth - 1));
+            _shr(T, Ctx->getConstantInt(Ty, TypeWidth - LogDiv));
+            _add(T, Src0);
+            _sar(T, Ctx->getConstantInt(Ty, LogDiv));
+          }
+          _mov(Dest, T);
+          return;
+        }
       }
-      _imul(T, Src1);
-      _mov(Dest, T);
-      break;
-    case InstArithmetic::Shl:
-      _mov(T, Src0);
-      if (!llvm::isa<Constant>(Src1))
-        Src1 = legalizeToVar(Src1, RegX8632::Reg_ecx);
-      _shl(T, Src1);
-      _mov(Dest, T);
-      break;
-    case InstArithmetic::Lshr:
-      _mov(T, Src0);
-      if (!llvm::isa<Constant>(Src1))
-        Src1 = legalizeToVar(Src1, RegX8632::Reg_ecx);
-      _shr(T, Src1);
+    }
+    Src1 = legalize(Src1, Legal_Reg | Legal_Mem);
+    if (isByteSizedArithType(Dest->getType())) {
+      _mov(T, Src0, RegX8632::Reg_eax);
+      _cbwdq(T, T);
+      _idiv(T, Src1, T);
       _mov(Dest, T);
-      break;
-    case InstArithmetic::Ashr:
-      _mov(T, Src0);
-      if (!llvm::isa<Constant>(Src1))
-        Src1 = legalizeToVar(Src1, RegX8632::Reg_ecx);
-      _sar(T, Src1);
+    } else {
+      T_edx = makeReg(IceType_i32, RegX8632::Reg_edx);
+      _mov(T, Src0, RegX8632::Reg_eax);
+      _cbwdq(T_edx, T);
+      _idiv(T, Src1, T_edx);
       _mov(Dest, T);
-      break;
-    case InstArithmetic::Udiv:
-      // div and idiv are the few arithmetic operators that do not allow
-      // immediates as the operand.
-      Src1 = legalize(Src1, Legal_Reg | Legal_Mem);
-      if (isByteSizedArithType(Dest->getType())) {
-        Variable *T_ah = nullptr;
-        Constant *Zero = Ctx->getConstantZero(IceType_i8);
-        _mov(T, Src0, RegX8632::Reg_eax);
-        _mov(T_ah, Zero, RegX8632::Reg_ah);
-        _div(T, Src1, T_ah);
-        _mov(Dest, T);
-      } else {
-        Constant *Zero = Ctx->getConstantZero(IceType_i32);
-        _mov(T, Src0, RegX8632::Reg_eax);
-        _mov(T_edx, Zero, RegX8632::Reg_edx);
-        _div(T, Src1, T_edx);
-        _mov(Dest, T);
-      }
-      break;
-    case InstArithmetic::Sdiv:
-      Src1 = legalize(Src1, Legal_Reg | Legal_Mem);
-      if (isByteSizedArithType(Dest->getType())) {
-        _mov(T, Src0, RegX8632::Reg_eax);
-        _cbwdq(T, T);
-        _idiv(T, Src1, T);
-        _mov(Dest, T);
-      } else {
-        T_edx = makeReg(IceType_i32, RegX8632::Reg_edx);
-        _mov(T, Src0, RegX8632::Reg_eax);
-        _cbwdq(T_edx, T);
-        _idiv(T, Src1, T_edx);
-        _mov(Dest, T);
-      }
-      break;
-    case InstArithmetic::Urem:
-      Src1 = legalize(Src1, Legal_Reg | Legal_Mem);
-      if (isByteSizedArithType(Dest->getType())) {
-        Variable *T_ah = nullptr;
-        Constant *Zero = Ctx->getConstantZero(IceType_i8);
-        _mov(T, Src0, RegX8632::Reg_eax);
-        _mov(T_ah, Zero, RegX8632::Reg_ah);
-        _div(T_ah, Src1, T);
-        _mov(Dest, T_ah);
-      } else {
-        Constant *Zero = Ctx->getConstantZero(IceType_i32);
-        _mov(T_edx, Zero, RegX8632::Reg_edx);
-        _mov(T, Src0, RegX8632::Reg_eax);
-        _div(T_edx, Src1, T);
-        _mov(Dest, T_edx);
-      }
-      break;
-    case InstArithmetic::Srem:
-      Src1 = legalize(Src1, Legal_Reg | Legal_Mem);
-      if (isByteSizedArithType(Dest->getType())) {
-        Variable *T_ah = makeReg(IceType_i8, RegX8632::Reg_ah);
-        _mov(T, Src0, RegX8632::Reg_eax);
-        _cbwdq(T, T);
-        Context.insert(InstFakeDef::create(Func, T_ah));
-        _idiv(T_ah, Src1, T);
-        _mov(Dest, T_ah);
-      } else {
-        T_edx = makeReg(IceType_i32, RegX8632::Reg_edx);
-        _mov(T, Src0, RegX8632::Reg_eax);
-        _cbwdq(T_edx, T);
-        _idiv(T_edx, Src1, T);
-        _mov(Dest, T_edx);
+    }
+    break;
+  case InstArithmetic::Urem:
+    Src1 = legalize(Src1, Legal_Reg | Legal_Mem);
+    if (isByteSizedArithType(Dest->getType())) {
+      Variable *T_ah = nullptr;
+      Constant *Zero = Ctx->getConstantZero(IceType_i8);
+      _mov(T, Src0, RegX8632::Reg_eax);
+      _mov(T_ah, Zero, RegX8632::Reg_ah);
+      _div(T_ah, Src1, T);
+      _mov(Dest, T_ah);
+    } else {
+      Constant *Zero = Ctx->getConstantZero(IceType_i32);
+      _mov(T_edx, Zero, RegX8632::Reg_edx);
+      _mov(T, Src0, RegX8632::Reg_eax);
+      _div(T_edx, Src1, T);
+      _mov(Dest, T_edx);
+    }
+    break;
+  case InstArithmetic::Srem:
+    // TODO(stichnot): Enable this after doing better performance
+    // and cross testing.
+    if (false && Ctx->getFlags().getOptLevel() >= Opt_1) {
+      // Optimize mod by constant power of 2, but not for Om1 or O0,
+      // just to keep things simple there.
+      if (auto *C = llvm::dyn_cast<ConstantInteger32>(Src1)) {
+        int32_t Divisor = C->getValue();
+        uint32_t UDivisor = static_cast<uint32_t>(Divisor);
+        if (Divisor > 0 && llvm::isPowerOf2_32(UDivisor)) {
+          uint32_t LogDiv = llvm::Log2_32(UDivisor);
+          Type Ty = Dest->getType();
+          // LLVM does the following for dest=src%(1<<log):
+          //   t=src
+          //   sar t,typewidth-1 // -1 if src is negative, 0 if not
+          //   shr t,typewidth-log
+          //   add t,src
+          //   and t, -(1<<log)
+          //   sub t,src
+          //   neg t
+          //   dest=t
+          uint32_t TypeWidth = X86_CHAR_BIT * typeWidthInBytes(Ty);
+          // If for some reason we are dividing by 1, just assign 0.
+          if (LogDiv == 0) {
+            _mov(Dest, Ctx->getConstantZero(Ty));
+            return;
+          }
+          _mov(T, Src0);
+          // The initial sar is unnecessary when dividing by 2.
+          if (LogDiv > 1)
+            _sar(T, Ctx->getConstantInt(Ty, TypeWidth - 1));
+          _shr(T, Ctx->getConstantInt(Ty, TypeWidth - LogDiv));
+          _add(T, Src0);
+          _and(T, Ctx->getConstantInt(Ty, -(1 << LogDiv)));
+          _sub(T, Src0);
+          _neg(T);
+          _mov(Dest, T);
+          return;
+        }
       }
-      break;
-    case InstArithmetic::Fadd:
-      _mov(T, Src0);
-      _addss(T, Src1);
-      _mov(Dest, T);
-      break;
-    case InstArithmetic::Fsub:
-      _mov(T, Src0);
-      _subss(T, Src1);
-      _mov(Dest, T);
-      break;
-    case InstArithmetic::Fmul:
-      _mov(T, Src0);
-      _mulss(T, Src1);
-      _mov(Dest, T);
-      break;
-    case InstArithmetic::Fdiv:
-      _mov(T, Src0);
-      _divss(T, Src1);
-      _mov(Dest, T);
-      break;
-    case InstArithmetic::Frem: {
-      const SizeT MaxSrcs = 2;
-      Type Ty = Dest->getType();
-      InstCall *Call =
-          makeHelperCall(isFloat32Asserting32Or64(Ty) ? H_frem_f32 : H_frem_f64,
-                         Dest, MaxSrcs);
-      Call->addArg(Src0);
-      Call->addArg(Src1);
-      return lowerCall(Call);
-    } break;
     }
+    Src1 = legalize(Src1, Legal_Reg | Legal_Mem);
+    if (isByteSizedArithType(Dest->getType())) {
+      Variable *T_ah = makeReg(IceType_i8, RegX8632::Reg_ah);
+      _mov(T, Src0, RegX8632::Reg_eax);
+      _cbwdq(T, T);
+      Context.insert(InstFakeDef::create(Func, T_ah));
+      _idiv(T_ah, Src1, T);
+      _mov(Dest, T_ah);
+    } else {
+      T_edx = makeReg(IceType_i32, RegX8632::Reg_edx);
+      _mov(T, Src0, RegX8632::Reg_eax);
+      _cbwdq(T_edx, T);
+      _idiv(T_edx, Src1, T);
+      _mov(Dest, T_edx);
+    }
+    break;
+  case InstArithmetic::Fadd:
+    _mov(T, Src0);
+    _addss(T, Src1);
+    _mov(Dest, T);
+    break;
+  case InstArithmetic::Fsub:
+    _mov(T, Src0);
+    _subss(T, Src1);
+    _mov(Dest, T);
+    break;
+  case InstArithmetic::Fmul:
+    _mov(T, Src0);
+    _mulss(T, Src1);
+    _mov(Dest, T);
+    break;
+  case InstArithmetic::Fdiv:
+    _mov(T, Src0);
+    _divss(T, Src1);
+    _mov(Dest, T);
+    break;
+  case InstArithmetic::Frem: {
+    const SizeT MaxSrcs = 2;
+    Type Ty = Dest->getType();
+    InstCall *Call = makeHelperCall(
+        isFloat32Asserting32Or64(Ty) ? H_frem_f32 : H_frem_f64, Dest, MaxSrcs);
+    Call->addArg(Src0);
+    Call->addArg(Src1);
+    return lowerCall(Call);
+  }
   }
 }
 
@@ -1839,18 +2067,27 @@ void TargetX8632::lowerAssign(const InstAssign *Inst) {
     _mov(DestHi, T_Hi);
   } else {
     Operand *RI;
-    if (Dest->hasReg())
+    if (Dest->hasReg()) {
       // If Dest already has a physical register, then legalize the
       // Src operand into a Variable with the same register
       // assignment.  This is mostly a workaround for advanced phi
       // lowering's ad-hoc register allocation which assumes no
       // register allocation is needed when at least one of the
       // operands is non-memory.
-      RI = legalize(Src0, Legal_Reg, Dest->getRegNum());
-    else
+
+      // qining: if we have a physical register for the dest variable,
+      // we can enable our constant blinding or pooling again. Note
+      // this is only for advancedPhiLowering(), the flag flip should
+      // leave no other side effect.
+      {
+        BoolFlagSaver B(RandomizationPoolingPaused, false);
+        RI = legalize(Src0, Legal_Reg, Dest->getRegNum());
+      }
+    } else {
       // If Dest could be a stack operand, then RI must be a physical
       // register or a scalar integer immediate.
       RI = legalize(Src0, Legal_Reg | Legal_Imm);
+    }
     if (isVectorType(Dest->getType()))
       _movp(Dest, RI);
     else
@@ -3119,10 +3356,11 @@ void TargetX8632::lowerIntrinsicCall(const InstIntrinsicCall *Instr) {
       Func->setError("Unexpected memory ordering for AtomicRMW");
       return;
     }
-    lowerAtomicRMW(Instr->getDest(),
-                   static_cast<uint32_t>(llvm::cast<ConstantInteger32>(
-                                             Instr->getArg(0))->getValue()),
-                   Instr->getArg(1), Instr->getArg(2));
+    lowerAtomicRMW(
+        Instr->getDest(),
+        static_cast<uint32_t>(
+            llvm::cast<ConstantInteger32>(Instr->getArg(0))->getValue()),
+        Instr->getArg(1), Instr->getArg(2));
     return;
   case Intrinsics::AtomicStore: {
     if (!Intrinsics::isMemoryOrderValid(
@@ -4325,6 +4563,10 @@ void TargetX8632::lowerUnreachable(const InstUnreachable * /*Inst*/) { _ud2(); }
 // turned into zeroes, since loOperand() and hiOperand() don't expect
 // Undef input.
 void TargetX8632::prelowerPhis() {
+  // Pause constant blinding or pooling, blinding or pooling will be done later
+  // during phi lowering assignments
+  BoolFlagSaver B(RandomizationPoolingPaused, true);
+
   CfgNode *Node = Context.getNode();
   for (Inst &I : Node->getPhis()) {
     auto Phi = llvm::dyn_cast<InstPhi>(&I);
@@ -4424,7 +4666,28 @@ void TargetX8632::lowerPhiAssignments(CfgNode *Node,
     Context.rewind();
     auto Assign = llvm::dyn_cast<InstAssign>(&I);
     Variable *Dest = Assign->getDest();
+
+    // qining: Here is an ugly hack for phi.ll test.
+    // In function test_split_undef_int_vec, the advanced phi
+    // lowering process will find an assignment of undefined
+    // vector. This vector, as the Src here, will crash if it
+    // go through legalize(). legalize() will create new variable
+    // with makeVectorOfZeros(), but this new variable will be
+    // assigned a stack slot. This will fail the assertion in
+    // IceInstX8632.cpp:789, as XmmEmitterRegOp() complain:
+    // Var->hasReg() fails. Note this failure is irrelevant to
+    // randomization or pooling of constants.
+    // So, we do not call legalize() to add pool label for the
+    // src operands of phi assignment instructions.
+    // Instead, we manually add pool label for constant float and
+    // constant double values here.
+    // Note going through legalize() does not affect the testing
+    // results of SPEC2K and xtests.
     Operand *Src = Assign->getSrc(0);
+    if (!llvm::isa<ConstantUndef>(Assign->getSrc(0))) {
+      Src = legalize(Src);
+    }
+
     Variable *SrcVar = llvm::dyn_cast<Variable>(Src);
     // Use normal assignment lowering, except lower mem=mem specially
     // so we can register-allocate at the same time.
@@ -4600,6 +4863,7 @@ Operand *TargetX8632::legalize(Operand *From, LegalMask Allowed,
   // work, e.g. allow the shl shift amount to be either an immediate
   // or in ecx.)
   assert(RegNum == Variable::NoRegister || Allowed == Legal_Reg);
+
   if (auto Mem = llvm::dyn_cast<OperandX8632Mem>(From)) {
     // Before doing anything with a Mem operand, we need to ensure
     // that the Base and Index components are in physical registers.
@@ -4614,11 +4878,14 @@ Operand *TargetX8632::legalize(Operand *From, LegalMask Allowed,
       RegIndex = legalizeToVar(Index);
     }
     if (Base != RegBase || Index != RegIndex) {
-      From =
+      Mem =
           OperandX8632Mem::create(Func, Ty, RegBase, Mem->getOffset(), RegIndex,
                                   Mem->getShift(), Mem->getSegmentRegister());
     }
 
+    // qining: For all Memory Operands, we do randomization/pooling here
+    From = randomizeOrPoolImmediate(Mem);
+
     if (!(Allowed & Legal_Mem)) {
       From = copyToReg(From, RegNum);
     }
@@ -4643,6 +4910,16 @@ Operand *TargetX8632::legalize(Operand *From, LegalMask Allowed,
     }
     // There should be no constants of vector type (other than undef).
     assert(!isVectorType(Ty));
+
+    // If the operand is an 32 bit constant integer, we should check
+    // whether we need to randomize it or pool it.
+    if (ConstantInteger32 *C = llvm::dyn_cast<ConstantInteger32>(From)) {
+      Operand *NewFrom = randomizeOrPoolImmediate(C, RegNum);
+      if (NewFrom != From) {
+        return NewFrom;
+      }
+    }
+
     // Convert a scalar floating point constant into an explicit
     // memory operand.
     if (isScalarFloatingType(Ty)) {
@@ -4650,6 +4927,7 @@ Operand *TargetX8632::legalize(Operand *From, LegalMask Allowed,
       std::string Buffer;
       llvm::raw_string_ostream StrBuf(Buffer);
       llvm::cast<Constant>(From)->emitPoolLabel(StrBuf);
+      llvm::cast<Constant>(From)->shouldBePooled = true;
       Constant *Offset = Ctx->getConstantSym(0, StrBuf.str(), true);
       From = OperandX8632Mem::create(Func, Ty, Base, Offset);
     }
@@ -4706,25 +4984,38 @@ Operand *TargetX8632::legalizeSrc0ForCmp(Operand *Src0, Operand *Src1) {
   return legalize(Src0, IsSrc1ImmOrReg ? (Legal_Reg | Legal_Mem) : Legal_Reg);
 }
 
-OperandX8632Mem *TargetX8632::formMemoryOperand(Operand *Operand, Type Ty,
+OperandX8632Mem *TargetX8632::formMemoryOperand(Operand *Opnd, Type Ty,
                                                 bool DoLegalize) {
-  OperandX8632Mem *Mem = llvm::dyn_cast<OperandX8632Mem>(Operand);
+  OperandX8632Mem *Mem = llvm::dyn_cast<OperandX8632Mem>(Opnd);
   // It may be the case that address mode optimization already creates
   // an OperandX8632Mem, so in that case it wouldn't need another level
   // of transformation.
   if (!Mem) {
-    Variable *Base = llvm::dyn_cast<Variable>(Operand);
-    Constant *Offset = llvm::dyn_cast<Constant>(Operand);
+    Variable *Base = llvm::dyn_cast<Variable>(Opnd);
+    Constant *Offset = llvm::dyn_cast<Constant>(Opnd);
     assert(Base || Offset);
     if (Offset) {
-      // Make sure Offset is not undef.
-      Offset = llvm::cast<Constant>(legalize(Offset));
+      // qining: during memory operand building, we do not
+      // blind or pool the constant offset, we will work on
+      // the whole memory operand later as one entity later,
+      // this save one instruction. By turning blinding and
+      // pooling off, we guarantee legalize(Offset) will return
+      // a constant*
+      {
+        BoolFlagSaver B(RandomizationPoolingPaused, true);
+
+        Offset = llvm::cast<Constant>(legalize(Offset));
+      }
+
       assert(llvm::isa<ConstantInteger32>(Offset) ||
              llvm::isa<ConstantRelocatable>(Offset));
     }
     Mem = OperandX8632Mem::create(Func, Ty, Base, Offset);
   }
-  return llvm::cast<OperandX8632Mem>(DoLegalize ? legalize(Mem) : Mem);
+  // qining: do legalization, which contains randomization/pooling
+  // or do randomization/pooling.
+  return llvm::cast<OperandX8632Mem>(
+      DoLegalize ? legalize(Mem) : randomizeOrPoolImmediate(Mem));
 }
 
 Variable *TargetX8632::makeReg(Type Type, int32_t RegNum) {
@@ -4965,6 +5256,45 @@ const char *PoolTypeConverter<double>::TypeName = "double";
 const char *PoolTypeConverter<double>::AsmTag = ".quad";
 const char *PoolTypeConverter<double>::PrintfString = "0x%llx";
 
+// Add converter for int type constant pooling
+template <> struct PoolTypeConverter<int> {

[Jim Stichnoth, 2015/06/19 16:51:03]

Please use uint32_t/uint16_t/uint8_t instead of int/short/char.  (I think the
unsigned versions are fine, but if not, use int*_t versions.)

[qining, 2015/06/19 20:22:26]

Done. I think both signed and unsigned should be fine, as they are only used in
creating the PoolTypeConverter struct, not used directly in any logic.

+  typedef uint32_t PrimitiveIntType;
+  typedef ConstantInteger32 IceType;
+  static const Type Ty = IceType_i32;
+  static const char *TypeName;
+  static const char *AsmTag;
+  static const char *PrintfString;
+};
+const char *PoolTypeConverter<int>::TypeName = "i32";
+const char *PoolTypeConverter<int>::AsmTag = ".long";
+const char *PoolTypeConverter<int>::PrintfString = "0x%x";
+
+// Add converter for int type constant pooling
+template <> struct PoolTypeConverter<short> {
+  typedef uint32_t PrimitiveIntType;
+  typedef ConstantInteger32 IceType;
+  static const Type Ty = IceType_i16;
+  static const char *TypeName;
+  static const char *AsmTag;
+  static const char *PrintfString;
+};
+const char *PoolTypeConverter<short>::TypeName = "i16";
+const char *PoolTypeConverter<short>::AsmTag = ".short";
+const char *PoolTypeConverter<short>::PrintfString = "0x%x";
+
+// Add converter for int type constant pooling
+template <> struct PoolTypeConverter<char> {
+  typedef uint32_t PrimitiveIntType;
+  typedef ConstantInteger32 IceType;
+  static const Type Ty = IceType_i8;
+  static const char *TypeName;
+  static const char *AsmTag;
+  static const char *PrintfString;
+};
+const char *PoolTypeConverter<char>::TypeName = "i8";
+const char *PoolTypeConverter<char>::AsmTag = ".byte";
+const char *PoolTypeConverter<char>::PrintfString = "0x%x";
+
 template <typename T>
 void TargetDataX8632::emitConstantPool(GlobalContext *Ctx) {
   if (!ALLOW_DUMP)
@@ -4978,6 +5308,8 @@ void TargetDataX8632::emitConstantPool(GlobalContext *Ctx) {
       << "\n";
   Str << "\t.align\t" << Align << "\n";
   for (Constant *C : Pool) {
+    if (!C->shouldBePooled)
+      continue;
     typename T::IceType *Const = llvm::cast<typename T::IceType>(C);
     typename T::IceType::PrimType Value = Const->getValue();
     // Use memcpy() to copy bits from Value into RawValue in a way
@@ -5004,12 +5336,22 @@ void TargetDataX8632::lowerConstants() const {
   switch (Ctx->getFlags().getOutFileType()) {
   case FT_Elf: {
     ELFObjectWriter *Writer = Ctx->getObjectWriter();
+
+    Writer->writeConstantPool<ConstantInteger32>(IceType_i8);
+    Writer->writeConstantPool<ConstantInteger32>(IceType_i16);
+    Writer->writeConstantPool<ConstantInteger32>(IceType_i32);
+
     Writer->writeConstantPool<ConstantFloat>(IceType_f32);
     Writer->writeConstantPool<ConstantDouble>(IceType_f64);
   } break;
   case FT_Asm:
   case FT_Iasm: {
     OstreamLocker L(Ctx);
+
+    emitConstantPool<PoolTypeConverter<char>>(Ctx);
+    emitConstantPool<PoolTypeConverter<short>>(Ctx);
+    emitConstantPool<PoolTypeConverter<int>>(Ctx);
+
     emitConstantPool<PoolTypeConverter<float>>(Ctx);
     emitConstantPool<PoolTypeConverter<double>>(Ctx);
   } break;
@@ -5019,4 +5361,197 @@ void TargetDataX8632::lowerConstants() const {
 TargetHeaderX8632::TargetHeaderX8632(GlobalContext *Ctx)
     : TargetHeaderLowering(Ctx) {}
 
+// Blind/pool an Immediate
+Operand *TargetX8632::randomizeOrPoolImmediate(Constant *Immediate,
+                                               int32_t RegNum) {
+  assert(llvm::isa<ConstantInteger32>(Immediate) ||
+         llvm::isa<ConstantRelocatable>(Immediate));
+  if (Ctx->getFlags().getRandomizeAndPoolImmediatesOption() == RPI_None ||
+      RandomizationPoolingPaused == true) {
+    // immediates randomization/pool turned off
+    return Immediate;
+  }
+  if (Constant *C = llvm::dyn_cast_or_null<Constant>(Immediate)) {
+    if (C->shouldBeRandomizedOrPooled(Ctx)) {
+      Ctx->statsUpdateRPImms();
+      if (Ctx->getFlags().getRandomizeAndPoolImmediatesOption() ==
+          RPI_Randomize) {
+        // blind the constant
+        // FROM:
+        //  imm
+        // TO:
+        //  insert: mov imm+cookie, Reg
+        //  insert: lea -cookie[Reg], Reg

[Jim Stichnoth, 2015/06/19 16:51:03]

Explain in a comment that lea is used (as opposed to, say, xor) to avoid
affecting the flags.

[qining, 2015/06/19 20:22:26]

Done.

+        //  => Reg
+        // If we have already assigned a phy register, we must come from
+        // andvancedPhiLowering()=>lowerAssign(). In this case we should reuse
+        // the assigned register as this assignment is that start of its use-def
+        // chain. So we add RegNum argument here.
+        Variable *Reg = makeReg(IceType_i32, RegNum);
+        ConstantInteger32 *Integer = llvm::cast<ConstantInteger32>(Immediate);
+        uint32_t Value = Integer->getValue();
+        uint32_t Cookie = Ctx->getRandomizationCookie();
+        _mov(Reg, Ctx->getConstantInt(IceType_i32, Cookie + Value));
+        Constant *Offset = Ctx->getConstantInt(IceType_i32, 0 - Cookie);
+        _lea(Reg,
+             OperandX8632Mem::create(Func, IceType_i32, Reg, Offset, NULL, 0));

[Jim Stichnoth, 2015/06/19 16:51:03]

nullptr

[qining, 2015/06/19 20:22:26]

Done.

+        // make sure liveness analysis won't kill this variable, otherwise a
+        // liveness
+        // assertion will be triggered.
+        _set_dest_nonkillable();
+        if (Immediate->getType() != IceType_i32) {
+          Variable *TruncReg = makeReg(Immediate->getType(), RegNum);
+          _mov(TruncReg, Reg);
+          return TruncReg;
+        }
+        return Reg;
+      }
+      if (Ctx->getFlags().getRandomizeAndPoolImmediatesOption() == RPI_Pool) {
+        // pool the constant
+        // FROM:
+        //  imm
+        // TO:
+        //  insert: mov $label, Reg
+        //  => Reg
+        assert(Ctx->getFlags().getRandomizeAndPoolImmediatesOption() ==
+               RPI_Pool);
+        Immediate->shouldBePooled = true;
+        // if we have already assigned a phy register, we must come from
+        // andvancedPhiLowering()=>lowerAssign(). In this case we should reuse
+        // the assigned register as this assignment is that start of its use-def
+        // chain. So we add RegNum argument here.
+        Variable *Reg = makeReg(Immediate->getType(), RegNum);
+        IceString Label;
+        llvm::raw_string_ostream Label_stream(Label);
+        Immediate->emitPoolLabel(Label_stream);
+        const RelocOffsetT Offset = 0;
+        const bool SuppressMangling = true;
+        Constant *Symbol =
+            Ctx->getConstantSym(Offset, Label_stream.str(), SuppressMangling);
+        OperandX8632Mem *MemOperand =
+            OperandX8632Mem::create(Func, Immediate->getType(), NULL, Symbol);
+        _mov(Reg, MemOperand);
+        return Reg;
+      }
+      assert("Unsupported -randomize-pool-immediates option" && false);
+    }
+  }
+  // the constant Immediate is not eligible for blinding/pooling
+  return Immediate;
+}
+
+OperandX8632Mem *
+TargetX8632::randomizeOrPoolImmediate(OperandX8632Mem *MemOperand,
+                                      int32_t RegNum) {
+  assert(MemOperand);
+  if (Ctx->getFlags().getRandomizeAndPoolImmediatesOption() == RPI_None ||
+      RandomizationPoolingPaused == true) {
+    // immediates randomization/pooling is turned off
+    return MemOperand;
+  }
+
+  if (Constant *C = llvm::dyn_cast_or_null<Constant>(MemOperand->getOffset())) {
+    if (C->shouldBeRandomizedOrPooled(Ctx)) {
+      // The offset of this mem operand should be blinded or pooled
+      Ctx->statsUpdateRPImms();
+      if (Ctx->getFlags().getRandomizeAndPoolImmediatesOption() ==
+          RPI_Randomize) {
+        // blind the constant offset
+        // FROM:
+        //  offset[base, index, shift]
+        // TO:
+        //  insert: lea offset+cookie[base], RegTemp
+        //  => -cookie[RegTemp, index, shift]
+        uint32_t Value =
+            llvm::dyn_cast<ConstantInteger32>(MemOperand->getOffset())
+                ->getValue();
+        uint32_t Cookie = Ctx->getRandomizationCookie();
+        Constant *Mask1 = Ctx->getConstantInt(
+            MemOperand->getOffset()->getType(), Cookie + Value);
+        Constant *Mask2 =
+            Ctx->getConstantInt(MemOperand->getOffset()->getType(), 0 - Cookie);
+
+        // qining: if the offset value is -cookie, this memory operand should
+        // have already been randomized, we just return it.
+        if(Value == -Cookie)  return MemOperand;

[Jim Stichnoth, 2015/06/19 16:51:03]

make format

Also, there's an interesting one-in-four-billion corner case where
Cookie==MININT and therefore Cookie==-Cookie.  Any issue there?

[qining, 2015/06/19 20:22:25]

I think Cookie==MIN_INT should still be fine.

Assume offset = 0x5, Cookie + offset => 0x80000005.
Then -cookie = 0x80000000,
so Cookie + offset - Cookie = 0x80000005 + 0x80000000 => 0x5.

If offset is -5 = 0xfffffffb, Cookie + offset => 0x7ffffffb
Cookie + offset - Cookie => 0xfffffffb = -5.

There overflow in the calculation above, if that isn't a problem, we should be
fine with here.

+
+        // qining: We need to make sure the MemOperand->getBase() has a physical
+        // register, if it is a variable!
+        if (MemOperand->getBase() != NULL)
+          MemOperand->getBase()->setWeightInfinite();
+        OperandX8632Mem *TempMemOperand = OperandX8632Mem::create(
+            Func, MemOperand->getType(), MemOperand->getBase(), Mask1);
+        // If we have already assigned a physical register, we must come from
+        // advancedPhiLowering()=>lowerAssign(). In this case we should reuse
+        // the assigned register as this assignment is that start of its use-def
+        // chain. So we add RegNum argument here.
+        Variable *RegTemp = makeReg(MemOperand->getOffset()->getType(), RegNum);
+        _lea(RegTemp, TempMemOperand);
+        // As source operand doesn't use the dstreg, we don't need to add
+        // _set_dest_nonkillable().
+        // qining: but if we use the same Dest Reg, that is, with RegNum
+        // assigned, we should add this _set_dest_nonkillable()
+        if (RegNum != Variable::NoRegister)
+          _set_dest_nonkillable();
+
+        OperandX8632Mem *NewMemOperand = OperandX8632Mem::create(
+            Func, MemOperand->getType(), RegTemp, Mask2, MemOperand->getIndex(),
+            MemOperand->getShift(), MemOperand->getSegmentRegister());
+
+        return NewMemOperand;
+      }
+      if (Ctx->getFlags().getRandomizeAndPoolImmediatesOption() == RPI_Pool) {
+        // pool the constant offset
+        // FROM:
+        //  offset[base, index, shift]
+        // TO:
+        //  insert: mov $label, RegTemp
+        //  insert: lea [base, RegTemp], RegTemp
+        //  =>[RegTemp, index, shift]
+        assert(Ctx->getFlags().getRandomizeAndPoolImmediatesOption() ==
+               RPI_Pool);
+        // qining: Mem operand should never exist as source operands in phi
+        // lowering
+        // assignments, so there is no need to reuse any registers here.
+        // However, for phi lowering, we should not ask for new physical
+        // registers in general.
+        // However, if we do meet MemOperand during phi lowering, we should not
+        // blind or pool the immediates for now
+        if (RegNum != Variable::NoRegister)
+          return MemOperand;
+        Variable *RegTemp = makeReg(IceType_i32);
+        IceString Label;
+        llvm::raw_string_ostream Label_stream(Label);
+        MemOperand->getOffset()->emitPoolLabel(Label_stream);
+        MemOperand->getOffset()->shouldBePooled = true;
+        const RelocOffsetT SymOffset = 0;
+        bool SuppressMangling = true;
+        Constant *Symbol = Ctx->getConstantSym(SymOffset, Label_stream.str(),
+                                               SuppressMangling);
+        OperandX8632Mem *SymbolOperand = OperandX8632Mem::create(
+            Func, MemOperand->getOffset()->getType(), NULL, Symbol);
+        _mov(RegTemp, SymbolOperand);
+        // qining: We need to make sure the MemOperand->getBase() has a physical
+        // register! If we do not have base register here, we won't need an
+        // extra lea instruction anymore.
+        if (MemOperand->getBase()) {
+          OperandX8632Mem *CalculateOperand = OperandX8632Mem::create(
+              Func, MemOperand->getType(), MemOperand->getBase(), NULL, RegTemp,
+              0, MemOperand->getSegmentRegister());
+          _lea(RegTemp, CalculateOperand);
+          _set_dest_nonkillable();
+        }
+        OperandX8632Mem *NewMemOperand = OperandX8632Mem::create(
+            Func, MemOperand->getType(), RegTemp, NULL, MemOperand->getIndex(),
+            MemOperand->getShift(), MemOperand->getSegmentRegister());
+        return NewMemOperand;
+      }
+      assert("Unsupported -randomize-pool-immediates option" && false);
+    }
+  }
+  // the offset is not eligible for blinding or pooling, return the original
+  // mem operand
+  return MemOperand;
+}
+
 } // end of namespace Ice