<!-- _______________________________________________________________________ -->
<h4>
+ <a name="callclobber">Call-clobbered registers</a>
+</h4>
+
+<div>
+
+<p>Some machine instructions, like calls, clobber a large number of physical
+ registers. Rather than adding <code><def,dead></code> operands for
+ all of them, it is possible to use an <code>MO_RegisterMask</code> operand
+ instead. The register mask operand holds a bit mask of preserved registers,
+ and everything else is considered to be clobbered by the instruction. </p>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<h4>
<a name="ssa">Machine code in SSA form</a>
</h4>
MO_ExternalSymbol, ///< Name of external global symbol
MO_GlobalAddress, ///< Address of a global value
MO_BlockAddress, ///< Address of a basic block
+ MO_RegisterMask, ///< Mask of preserved registers.
MO_Metadata, ///< Metadata reference (for debug info)
MO_MCSymbol ///< MCSymbol reference (for debug/eh info)
};
const ConstantFP *CFP; // For MO_FPImmediate.
const ConstantInt *CI; // For MO_CImmediate. Integers > 64bit.
int64_t ImmVal; // For MO_Immediate.
+ const uint32_t *RegMask; // For MO_RegisterMask.
const MDNode *MD; // For MO_Metadata.
MCSymbol *Sym; // For MO_MCSymbol
bool isSymbol() const { return OpKind == MO_ExternalSymbol; }
/// isBlockAddress - Tests if this is a MO_BlockAddress operand.
bool isBlockAddress() const { return OpKind == MO_BlockAddress; }
+ /// isRegMask - Tests if this is a MO_RegisterMask operand.
+ bool isRegMask() const { return OpKind == MO_RegisterMask; }
/// isMetadata - Tests if this is a MO_Metadata operand.
bool isMetadata() const { return OpKind == MO_Metadata; }
bool isMCSymbol() const { return OpKind == MO_MCSymbol; }
+
//===--------------------------------------------------------------------===//
// Accessors for Register Operands
//===--------------------------------------------------------------------===//
return Contents.OffsetedInfo.Val.SymbolName;
}
+ /// clobbersPhysReg - Returns true if this RegMask operand clobbers PhysReg.
+ bool clobbersPhysReg(unsigned PhysReg) const {
+ assert(isRegMask() && "Wrong MachineOperand accessor");
+ // See TargetRegisterInfo.h.
+ assert(PhysReg < (1u << 30) && "Not a physical register");
+ return !Contents.RegMask ||
+ !(Contents.RegMask[PhysReg / 32] & (1u << PhysReg % 32));
+ }
+
+ /// getRegMask - Returns a bit mask of registers preserved by this RegMask
+ /// operand. A NULL pointer means that all registers are clobbered.
+ const uint32_t *getRegMask() const {
+ assert(isRegMask() && "Wrong MachineOperand accessor");
+ return Contents.RegMask;
+ }
+
const MDNode *getMetadata() const {
assert(isMetadata() && "Wrong MachineOperand accessor");
return Contents.MD;
Op.setTargetFlags(TargetFlags);
return Op;
}
+ /// CreateRegMask - Creates a register mask operand referencing Mask. The
+ /// operand does not take ownership of the memory referenced by Mask, it must
+ /// remain valid for the lifetime of the operand.
+ ///
+ /// A RegMask operand represents a set of non-clobbered physical registers on
+ /// an instruction that clobbers many registers, typically a call. The bit
+ /// mask has a bit set for each physreg that is preserved by this
+ /// instruction, as described in the documentation for
+ /// TargetRegisterInfo::getCallPreservedMask().
+ ///
+ /// Any physreg with a 0 bit in the mask is clobbered by the instruction.
+ ///
+ static MachineOperand CreateRegMask(const uint32_t *Mask) {
+ MachineOperand Op(MachineOperand::MO_RegisterMask);
+ Op.Contents.RegMask = Mask;
+ return Op;
+ }
static MachineOperand CreateMetadata(const MDNode *Meta) {
MachineOperand Op(MachineOperand::MO_Metadata);
Op.Contents.MD = Meta;
getOffset() == Other.getOffset();
case MachineOperand::MO_BlockAddress:
return getBlockAddress() == Other.getBlockAddress();
+ case MO_RegisterMask:
+ return getRegMask() == Other.getRegMask();
case MachineOperand::MO_MCSymbol:
return getMCSymbol() == Other.getMCSymbol();
case MachineOperand::MO_Metadata:
WriteAsOperand(OS, getBlockAddress(), /*PrintType=*/false);
OS << '>';
break;
+ case MachineOperand::MO_RegisterMask:
+ OS << (getRegMask() ? "<regmask>" : "<regmask:null>");
+ break;
case MachineOperand::MO_Metadata:
OS << '<';
WriteAsOperand(OS, getMetadata(), /*PrintType=*/false);