/// True if this is a varargs function that contains a musttail call.
bool HasMustTailInVarArgFunc;
+ /// True if this function contains a tail call. If so immutable objects like
+ /// function arguments are no longer so. A tail call *can* override fixed
+ /// stack objects like arguments so we can't treat them as immutable.
+ bool HasTailCall;
+
+ /// Not null, if shrink-wrapping found a better place for the prologue.
+ MachineBasicBlock *Save;
+ /// Not null, if shrink-wrapping found a better place for the epilogue.
+ MachineBasicBlock *Restore;
+
public:
explicit MachineFrameInfo(unsigned StackAlign, bool isStackRealign,
bool RealignOpt)
HasInlineAsmWithSPAdjust = false;
HasVAStart = false;
HasMustTailInVarArgFunc = false;
+ Save = nullptr;
+ Restore = nullptr;
+ HasTailCall = false;
}
/// hasStackObjects - Return true if there are any stack objects in this
bool hasMustTailInVarArgFunc() const { return HasMustTailInVarArgFunc; }
void setHasMustTailInVarArgFunc(bool B) { HasMustTailInVarArgFunc = B; }
+ /// Returns true if the function contains a tail call.
+ bool hasTailCall() const { return HasTailCall; }
+ void setHasTailCall() { HasTailCall = true; }
+
/// getMaxCallFrameSize - Return the maximum size of a call frame that must be
/// allocated for an outgoing function call. This is only available if
/// CallFrameSetup/Destroy pseudo instructions are used by the target, and
/// isImmutableObjectIndex - Returns true if the specified index corresponds
/// to an immutable object.
bool isImmutableObjectIndex(int ObjectIdx) const {
+ // Tail calling functions can clobber their function arguments.
+ if (HasTailCall)
+ return false;
assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
"Invalid Object Idx!");
return Objects[ObjectIdx+NumFixedObjects].isImmutable;
void setCalleeSavedInfoValid(bool v) { CSIValid = v; }
- /// getPristineRegs - Return a set of physical registers that are pristine on
- /// entry to the MBB.
+ MachineBasicBlock *getSavePoint() const { return Save; }
+ void setSavePoint(MachineBasicBlock *NewSave) { Save = NewSave; }
+ MachineBasicBlock *getRestorePoint() const { return Restore; }
+ void setRestorePoint(MachineBasicBlock *NewRestore) { Restore = NewRestore; }
+
+ /// Return a set of physical registers that are pristine.
///
/// Pristine registers hold a value that is useless to the current function,
- /// but that must be preserved - they are callee saved registers that have not
- /// been saved yet.
+ /// but that must be preserved - they are callee saved registers that are not
+ /// saved.
///
/// Before the PrologueEpilogueInserter has placed the CSR spill code, this
/// method always returns an empty set.
- BitVector getPristineRegs(const MachineBasicBlock *MBB) const;
+ BitVector getPristineRegs(const MachineFunction &MF) const;
/// print - Used by the MachineFunction printer to print information about
/// stack objects. Implemented in MachineFunction.cpp