1 //===-- llvm/CallingConvLower.h - Calling Conventions -----------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file declares the CCState and CCValAssign classes, used for lowering
11 // and implementing calling conventions.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_CODEGEN_CALLINGCONVLOWER_H
16 #define LLVM_CODEGEN_CALLINGCONVLOWER_H
18 #include "llvm/ADT/SmallVector.h"
19 #include "llvm/CodeGen/ValueTypes.h"
20 #include "llvm/CodeGen/SelectionDAGNodes.h"
23 class TargetRegisterInfo;
28 /// CCValAssign - Represent assignment of one arg/retval to a location.
32 Full, // The value fills the full location.
33 SExt, // The value is sign extended in the location.
34 ZExt, // The value is zero extended in the location.
35 AExt // The value is extended with undefined upper bits.
36 // TODO: a subset of the value is in the location.
39 /// ValNo - This is the value number begin assigned (e.g. an argument number).
42 /// Loc is either a stack offset or a register number.
45 /// isMem - True if this is a memory loc, false if it is a register loc.
48 /// Information about how the value is assigned.
51 /// ValVT - The type of the value being assigned.
54 /// LocVT - The type of the location being assigned to.
58 static CCValAssign getReg(unsigned ValNo, MVT::ValueType ValVT,
59 unsigned RegNo, MVT::ValueType LocVT,
70 static CCValAssign getMem(unsigned ValNo, MVT::ValueType ValVT,
71 unsigned Offset, MVT::ValueType LocVT,
83 unsigned getValNo() const { return ValNo; }
84 MVT::ValueType getValVT() const { return ValVT; }
86 bool isRegLoc() const { return !isMem; }
87 bool isMemLoc() const { return isMem; }
89 unsigned getLocReg() const { assert(isRegLoc()); return Loc; }
90 unsigned getLocMemOffset() const { assert(isMemLoc()); return Loc; }
91 MVT::ValueType getLocVT() const { return LocVT; }
93 LocInfo getLocInfo() const { return HTP; }
97 /// CCAssignFn - This function assigns a location for Val, updating State to
98 /// reflect the change.
99 typedef bool CCAssignFn(unsigned ValNo, MVT::ValueType ValVT,
100 MVT::ValueType LocVT, CCValAssign::LocInfo LocInfo,
101 ISD::ArgFlagsTy ArgFlags, CCState &State);
104 /// CCState - This class holds information needed while lowering arguments and
105 /// return values. It captures which registers are already assigned and which
106 /// stack slots are used. It provides accessors to allocate these values.
108 unsigned CallingConv;
110 const TargetMachine &TM;
111 const TargetRegisterInfo &TRI;
112 SmallVector<CCValAssign, 16> &Locs;
114 unsigned StackOffset;
115 SmallVector<uint32_t, 16> UsedRegs;
117 CCState(unsigned CC, bool isVarArg, const TargetMachine &TM,
118 SmallVector<CCValAssign, 16> &locs);
120 void addLoc(const CCValAssign &V) {
124 const TargetMachine &getTarget() const { return TM; }
125 unsigned getCallingConv() const { return CallingConv; }
126 bool isVarArg() const { return IsVarArg; }
128 unsigned getNextStackOffset() const { return StackOffset; }
130 /// isAllocated - Return true if the specified register (or an alias) is
132 bool isAllocated(unsigned Reg) const {
133 return UsedRegs[Reg/32] & (1 << (Reg&31));
136 /// AnalyzeFormalArguments - Analyze an ISD::FORMAL_ARGUMENTS node,
137 /// incorporating info about the formals into this state.
138 void AnalyzeFormalArguments(SDNode *TheArgs, CCAssignFn Fn);
140 /// AnalyzeReturn - Analyze the returned values of an ISD::RET node,
141 /// incorporating info about the result values into this state.
142 void AnalyzeReturn(SDNode *TheRet, CCAssignFn Fn);
144 /// AnalyzeCallOperands - Analyze an ISD::CALL node, incorporating info
145 /// about the passed values into this state.
146 void AnalyzeCallOperands(SDNode *TheCall, CCAssignFn Fn);
148 /// AnalyzeCallResult - Analyze the return values of an ISD::CALL node,
149 /// incorporating info about the passed values into this state.
150 void AnalyzeCallResult(SDNode *TheCall, CCAssignFn Fn);
153 /// getFirstUnallocated - Return the first unallocated register in the set, or
154 /// NumRegs if they are all allocated.
155 unsigned getFirstUnallocated(const unsigned *Regs, unsigned NumRegs) const {
156 for (unsigned i = 0; i != NumRegs; ++i)
157 if (!isAllocated(Regs[i]))
162 /// AllocateReg - Attempt to allocate one register. If it is not available,
163 /// return zero. Otherwise, return the register, marking it and any aliases
165 unsigned AllocateReg(unsigned Reg) {
166 if (isAllocated(Reg)) return 0;
171 /// AllocateReg - Attempt to allocate one of the specified registers. If none
172 /// are available, return zero. Otherwise, return the first one available,
173 /// marking it and any aliases as allocated.
174 unsigned AllocateReg(const unsigned *Regs, unsigned NumRegs) {
175 unsigned FirstUnalloc = getFirstUnallocated(Regs, NumRegs);
176 if (FirstUnalloc == NumRegs)
177 return 0; // Didn't find the reg.
179 // Mark the register and any aliases as allocated.
180 unsigned Reg = Regs[FirstUnalloc];
185 /// AllocateStack - Allocate a chunk of stack space with the specified size
187 unsigned AllocateStack(unsigned Size, unsigned Align) {
188 assert(Align && ((Align-1) & Align) == 0); // Align is power of 2.
189 StackOffset = ((StackOffset + Align-1) & ~(Align-1));
190 unsigned Result = StackOffset;
195 // HandleByVal - Allocate a stack slot large enough to pass an argument by
196 // value. The size and alignment information of the argument is encoded in its
197 // parameter attribute.
198 void HandleByVal(unsigned ValNo, MVT::ValueType ValVT,
199 MVT::ValueType LocVT, CCValAssign::LocInfo LocInfo,
200 int MinSize, int MinAlign, ISD::ArgFlagsTy ArgFlags);
203 /// MarkAllocated - Mark a register and all of its aliases as allocated.
204 void MarkAllocated(unsigned Reg);
209 } // end namespace llvm