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 ValVT,
59 unsigned RegNo, MVT LocVT,
70 static CCValAssign getMem(unsigned ValNo, MVT ValVT,
71 unsigned Offset, MVT LocVT,
83 unsigned getValNo() const { return ValNo; }
84 MVT 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 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 ValVT,
100 MVT 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 /// AnalyzeCallOperands - Same as above except it takes vectors of types
149 /// and argument flags.
150 void AnalyzeCallOperands(SmallVectorImpl<MVT> ArgVTs,
151 SmallVectorImpl<ISD::ArgFlagsTy> &Flags,
154 /// AnalyzeCallResult - Analyze the return values of an ISD::CALL node,
155 /// incorporating info about the passed values into this state.
156 void AnalyzeCallResult(SDNode *TheCall, CCAssignFn Fn);
159 /// getFirstUnallocated - Return the first unallocated register in the set, or
160 /// NumRegs if they are all allocated.
161 unsigned getFirstUnallocated(const unsigned *Regs, unsigned NumRegs) const {
162 for (unsigned i = 0; i != NumRegs; ++i)
163 if (!isAllocated(Regs[i]))
168 /// AllocateReg - Attempt to allocate one register. If it is not available,
169 /// return zero. Otherwise, return the register, marking it and any aliases
171 unsigned AllocateReg(unsigned Reg) {
172 if (isAllocated(Reg)) return 0;
177 /// Version of AllocateReg with extra register to be shadowed.
178 unsigned AllocateReg(unsigned Reg, unsigned ShadowReg) {
179 if (isAllocated(Reg)) return 0;
181 MarkAllocated(ShadowReg);
185 /// AllocateReg - Attempt to allocate one of the specified registers. If none
186 /// are available, return zero. Otherwise, return the first one available,
187 /// marking it and any aliases as allocated.
188 unsigned AllocateReg(const unsigned *Regs, unsigned NumRegs) {
189 unsigned FirstUnalloc = getFirstUnallocated(Regs, NumRegs);
190 if (FirstUnalloc == NumRegs)
191 return 0; // Didn't find the reg.
193 // Mark the register and any aliases as allocated.
194 unsigned Reg = Regs[FirstUnalloc];
199 /// Version of AllocateReg with list of registers to be shadowed.
200 unsigned AllocateReg(const unsigned *Regs, const unsigned *ShadowRegs,
202 unsigned FirstUnalloc = getFirstUnallocated(Regs, NumRegs);
203 if (FirstUnalloc == NumRegs)
204 return 0; // Didn't find the reg.
206 // Mark the register and any aliases as allocated.
207 unsigned Reg = Regs[FirstUnalloc], ShadowReg = ShadowRegs[FirstUnalloc];
209 MarkAllocated(ShadowReg);
213 /// AllocateStack - Allocate a chunk of stack space with the specified size
215 unsigned AllocateStack(unsigned Size, unsigned Align) {
216 assert(Align && ((Align-1) & Align) == 0); // Align is power of 2.
217 StackOffset = ((StackOffset + Align-1) & ~(Align-1));
218 unsigned Result = StackOffset;
223 // HandleByVal - Allocate a stack slot large enough to pass an argument by
224 // value. The size and alignment information of the argument is encoded in its
225 // parameter attribute.
226 void HandleByVal(unsigned ValNo, MVT ValVT,
227 MVT LocVT, CCValAssign::LocInfo LocInfo,
228 int MinSize, int MinAlign, ISD::ArgFlagsTy ArgFlags);
231 /// MarkAllocated - Mark a register and all of its aliases as allocated.
232 void MarkAllocated(unsigned Reg);
237 } // end namespace llvm