Subzero. Implements x86-64 lowerCall.

src/IceTargetLoweringX86BaseImpl.h

 //===- subzero/src/IceTargetLoweringX86BaseImpl.h - x86 lowering -*- C++ -*-==//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 2108 matching lines @@
     }
   }
 
   Operand *Src0 = legalize(Cond, Legal_Reg | Legal_Mem);
   Constant *Zero = Ctx->getConstantZero(IceType_i32);
   _cmp(Src0, Zero);
   _br(Traits::Cond::Br_ne, Inst->getTargetTrue(), Inst->getTargetFalse());
 }
 
 template <class Machine>
-void TargetX86Base<Machine>::lowerCall(const InstCall *Instr) {
-  // x86-32 calling convention:
-  //
-  // * At the point before the call, the stack must be aligned to 16
-  // bytes.
-  //
-  // * The first four arguments of vector type, regardless of their
-  // position relative to the other arguments in the argument list, are
-  // placed in registers xmm0 - xmm3.
-  //
-  // * Other arguments are pushed onto the stack in right-to-left order,
-  // such that the left-most argument ends up on the top of the stack at
-  // the lowest memory address.
-  //
-  // * Stack arguments of vector type are aligned to start at the next
-  // highest multiple of 16 bytes.  Other stack arguments are aligned to
-  // 4 bytes.
-  //
-  // This intends to match the section "IA-32 Function Calling
-  // Convention" of the document "OS X ABI Function Call Guide" by
-  // Apple.
-  NeedsStackAlignment = true;
-
-  typedef std::vector<Operand *> OperandList;
-  OperandList XmmArgs;
-  OperandList StackArgs, StackArgLocations;
-  uint32_t ParameterAreaSizeBytes = 0;
-
-  // Classify each argument operand according to the location where the
-  // argument is passed.
-  for (SizeT i = 0, NumArgs = Instr->getNumArgs(); i < NumArgs; ++i) {
-    Operand *Arg = Instr->getArg(i);
-    Type Ty = Arg->getType();
-    // The PNaCl ABI requires the width of arguments to be at least 32 bits.
-    assert(typeWidthInBytes(Ty) >= 4);
-    if (isVectorType(Ty) && XmmArgs.size() < Traits::X86_MAX_XMM_ARGS) {
-      XmmArgs.push_back(Arg);
-    } else {
-      StackArgs.push_back(Arg);
-      if (isVectorType(Arg->getType())) {
-        ParameterAreaSizeBytes =
-            Traits::applyStackAlignment(ParameterAreaSizeBytes);
-      }
-      Variable *esp =
-          Func->getTarget()->getPhysicalRegister(Traits::RegisterSet::Reg_esp);
-      Constant *Loc = Ctx->getConstantInt32(ParameterAreaSizeBytes);
-      StackArgLocations.push_back(
-          Traits::X86OperandMem::create(Func, Ty, esp, Loc));
-      ParameterAreaSizeBytes += typeWidthInBytesOnStack(Arg->getType());
-    }
-  }
-
-  // Adjust the parameter area so that the stack is aligned.  It is
-  // assumed that the stack is already aligned at the start of the
-  // calling sequence.
-  ParameterAreaSizeBytes = Traits::applyStackAlignment(ParameterAreaSizeBytes);
-
-  // Subtract the appropriate amount for the argument area.  This also
-  // takes care of setting the stack adjustment during emission.
-  //
-  // TODO: If for some reason the call instruction gets dead-code
-  // eliminated after lowering, we would need to ensure that the
-  // pre-call and the post-call esp adjustment get eliminated as well.
-  if (ParameterAreaSizeBytes) {
-    _adjust_stack(ParameterAreaSizeBytes);
-  }
-
-  // Copy arguments that are passed on the stack to the appropriate
-  // stack locations.
-  for (SizeT i = 0, e = StackArgs.size(); i < e; ++i) {
-    lowerStore(InstStore::create(Func, StackArgs[i], StackArgLocations[i]));
-  }
-
-  // Copy arguments to be passed in registers to the appropriate
-  // registers.
-  // TODO: Investigate the impact of lowering arguments passed in
-  // registers after lowering stack arguments as opposed to the other
-  // way around.  Lowering register arguments after stack arguments may
-  // reduce register pressure.  On the other hand, lowering register
-  // arguments first (before stack arguments) may result in more compact
-  // code, as the memory operand displacements may end up being smaller
-  // before any stack adjustment is done.
-  for (SizeT i = 0, NumXmmArgs = XmmArgs.size(); i < NumXmmArgs; ++i) {
-    Variable *Reg =
-        legalizeToReg(XmmArgs[i], Traits::RegisterSet::Reg_xmm0 + i);
-    // Generate a FakeUse of register arguments so that they do not get
-    // dead code eliminated as a result of the FakeKill of scratch
-    // registers after the call.
-    Context.insert(InstFakeUse::create(Func, Reg));
-  }
-  // Generate the call instruction.  Assign its result to a temporary
-  // with high register allocation weight.
-  Variable *Dest = Instr->getDest();
-  // ReturnReg doubles as ReturnRegLo as necessary.
-  Variable *ReturnReg = nullptr;
-  Variable *ReturnRegHi = nullptr;
-  if (Dest) {
-    switch (Dest->getType()) {
-    case IceType_NUM:
-      llvm_unreachable("Invalid Call dest type");
-      break;
-    case IceType_void:
-      break;
-    case IceType_i1:
-    case IceType_i8:
-    case IceType_i16:
-    case IceType_i32:
-      ReturnReg = makeReg(Dest->getType(), Traits::RegisterSet::Reg_eax);
-      break;
-    case IceType_i64:
-      ReturnReg = makeReg(IceType_i32, Traits::RegisterSet::Reg_eax);
-      ReturnRegHi = makeReg(IceType_i32, Traits::RegisterSet::Reg_edx);
-      break;
-    case IceType_f32:
-    case IceType_f64:
-      // Leave ReturnReg==ReturnRegHi==nullptr, and capture the result with
-      // the fstp instruction.
-      break;
-    case IceType_v4i1:
-    case IceType_v8i1:
-    case IceType_v16i1:
-    case IceType_v16i8:
-    case IceType_v8i16:
-    case IceType_v4i32:
-    case IceType_v4f32:
-      ReturnReg = makeReg(Dest->getType(), Traits::RegisterSet::Reg_xmm0);
-      break;
-    }
-  }
-  Operand *CallTarget = legalize(Instr->getCallTarget());
-  const bool NeedSandboxing = Ctx->getFlags().getUseSandboxing();
-  if (NeedSandboxing) {
-    if (llvm::isa<Constant>(CallTarget)) {
-      _bundle_lock(InstBundleLock::Opt_AlignToEnd);
-    } else {
-      Variable *CallTargetVar = nullptr;
-      _mov(CallTargetVar, CallTarget);
-      _bundle_lock(InstBundleLock::Opt_AlignToEnd);
-      const SizeT BundleSize =
-          1 << Func->getAssembler<>()->getBundleAlignLog2Bytes();
-      _and(CallTargetVar, Ctx->getConstantInt32(~(BundleSize - 1)));
-      CallTarget = CallTargetVar;
-    }
-  }
-  Inst *NewCall = Traits::Insts::Call::create(Func, ReturnReg, CallTarget);
-  Context.insert(NewCall);
-  if (NeedSandboxing)
-    _bundle_unlock();
-  if (ReturnRegHi)
-    Context.insert(InstFakeDef::create(Func, ReturnRegHi));
-
-  // Add the appropriate offset to esp.  The call instruction takes care
-  // of resetting the stack offset during emission.
-  if (ParameterAreaSizeBytes) {
-    Variable *esp =
-        Func->getTarget()->getPhysicalRegister(Traits::RegisterSet::Reg_esp);
-    _add(esp, Ctx->getConstantInt32(ParameterAreaSizeBytes));
-  }
-
-  // Insert a register-kill pseudo instruction.
-  Context.insert(InstFakeKill::create(Func, NewCall));
-
-  // Generate a FakeUse to keep the call live if necessary.
-  if (Instr->hasSideEffects() && ReturnReg) {
-    Inst *FakeUse = InstFakeUse::create(Func, ReturnReg);
-    Context.insert(FakeUse);
-  }
-
-  if (!Dest)
-    return;
-
-  // Assign the result of the call to Dest.
-  if (ReturnReg) {
-    if (ReturnRegHi) {
-      assert(Dest->getType() == IceType_i64);
-      split64(Dest);
-      Variable *DestLo = Dest->getLo();
-      Variable *DestHi = Dest->getHi();
-      _mov(DestLo, ReturnReg);
-      _mov(DestHi, ReturnRegHi);
-    } else {
-      assert(Dest->getType() == IceType_i32 || Dest->getType() == IceType_i16 ||
-             Dest->getType() == IceType_i8 || Dest->getType() == IceType_i1 ||
-             isVectorType(Dest->getType()));
-      if (isVectorType(Dest->getType())) {
-        _movp(Dest, ReturnReg);
-      } else {
-        _mov(Dest, ReturnReg);
-      }
-    }
-  } else if (isScalarFloatingType(Dest->getType())) {
-    // Special treatment for an FP function which returns its result in
-    // st(0).
-    // If Dest ends up being a physical xmm register, the fstp emit code
-    // will route st(0) through a temporary stack slot.
-    _fstp(Dest);
-    // Create a fake use of Dest in case it actually isn't used,
-    // because st(0) still needs to be popped.
-    Context.insert(InstFakeUse::create(Func, Dest));
-  }
-}
-
-template <class Machine>
 void TargetX86Base<Machine>::lowerCast(const InstCast *Inst) {
   // a = cast(b) ==> t=cast(b); a=t; (link t->b, link a->t, no overlap)
   InstCast::OpKind CastKind = Inst->getCastKind();
   Variable *Dest = Inst->getDest();
   switch (CastKind) {
   default:
     Func->setError("Cast type not supported");
     return;
   case InstCast::Sext: {
     // Src0RM is the source operand legalized to physical register or memory,
@@ skipping 3263 matching lines @@
   }
   // the offset is not eligible for blinding or pooling, return the original
   // mem operand
   return MemOperand;
 }
 
 } // end of namespace X86Internal
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERINGX86BASEIMPL_H