Commit 5edb40c0 authored by Fangrui Song's avatar Fangrui Song
Browse files

[SelectionDAG] Disallow indirect "i" constraint 

This allows us to delete InlineAsm::Constraint_i workarounds in
SelectionDAGISel::SelectInlineAsmMemoryOperand overrides and
TargetLowering::getInlineAsmMemConstraint overrides.

They were introduced to X86 in r237517 to prevent crashes for
constraints like "=*imr". They were later copied to other targets.
parent b1fb07dd

llvm/include/llvm/CodeGen/TargetLowering.h

+1 −3
Original line number Diff line number Diff line
@@ -3949,9 +3949,7 @@ public: 
                               StringRef Constraint, MVT VT) const;



  virtual unsigned getInlineAsmMemConstraint(StringRef ConstraintCode) const {

    if (ConstraintCode == "i")

      return InlineAsm::Constraint_i;

    else if (ConstraintCode == "m")

    if (ConstraintCode == "m")

      return InlineAsm::Constraint_m;

    return InlineAsm::Constraint_Unknown;

  }

llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp

+6 −0
Original line number Diff line number Diff line
@@ -4498,6 +4498,12 @@ static void ChooseConstraint(TargetLowering::AsmOperandInfo &OpInfo, 
    TargetLowering::ConstraintType CType =

      TLI.getConstraintType(OpInfo.Codes[i]);



    // Indirect 'other' or 'immediate' constraints are not allowed.

    if (OpInfo.isIndirect && !(CType == TargetLowering::C_Memory ||

                               CType == TargetLowering::C_Register ||

                               CType == TargetLowering::C_RegisterClass))

      continue;



    // If this is an 'other' or 'immediate' constraint, see if the operand is

    // valid for it. For example, on X86 we might have an 'rI' constraint. If

    // the operand is an integer in the range [0..31] we want to use I (saving a

llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp

+0 −1
Original line number Diff line number Diff line
@@ -304,7 +304,6 @@ bool AArch64DAGToDAGISel::SelectInlineAsmMemoryOperand( 
  switch(ConstraintID) {

  default:

    llvm_unreachable("Unexpected asm memory constraint");

  case InlineAsm::Constraint_i:

  case InlineAsm::Constraint_m:

  case InlineAsm::Constraint_Q:

    // We need to make sure that this one operand does not end up in XZR, thus

llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp

+0 −4
Original line number Diff line number Diff line
@@ -5047,10 +5047,6 @@ SelectInlineAsmMemoryOperand(const SDValue &Op, unsigned ConstraintID, 
  switch(ConstraintID) {

  default:

    llvm_unreachable("Unexpected asm memory constraint");

  case InlineAsm::Constraint_i:

    // FIXME: It seems strange that 'i' is needed here since it's supposed to

    //        be an immediate and not a memory constraint.

    LLVM_FALLTHROUGH;

  case InlineAsm::Constraint_m:

  case InlineAsm::Constraint_o:

  case InlineAsm::Constraint_Q:

llvm/lib/Target/Hexagon/HexagonISelDAGToDAG.cpp

+0 −1
Original line number Diff line number Diff line
@@ -916,7 +916,6 @@ SelectInlineAsmMemoryOperand(const SDValue &Op, unsigned ConstraintID, 
  switch (ConstraintID) {

  default:

    return true;

  case InlineAsm::Constraint_i:

  case InlineAsm::Constraint_o: // Offsetable.

  case InlineAsm::Constraint_v: // Not offsetable.

  case InlineAsm::Constraint_m: // Memory.