1 //===-- ARMSelectionDAGInfo.cpp - ARM SelectionDAG Info -------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements the ARMSelectionDAGInfo class.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #define DEBUG_TYPE "arm-selectiondag-info"
15 #include "ARMTargetMachine.h"
16 #include "llvm/DerivedTypes.h"
17 #include "llvm/CodeGen/SelectionDAG.h"
18 using namespace llvm;
19
ARMSelectionDAGInfo(const TargetMachine & TM)20 ARMSelectionDAGInfo::ARMSelectionDAGInfo(const TargetMachine &TM)
21 : TargetSelectionDAGInfo(TM),
22 Subtarget(&TM.getSubtarget<ARMSubtarget>()) {
23 }
24
~ARMSelectionDAGInfo()25 ARMSelectionDAGInfo::~ARMSelectionDAGInfo() {
26 }
27
28 SDValue
EmitTargetCodeForMemcpy(SelectionDAG & DAG,DebugLoc dl,SDValue Chain,SDValue Dst,SDValue Src,SDValue Size,unsigned Align,bool isVolatile,bool AlwaysInline,MachinePointerInfo DstPtrInfo,MachinePointerInfo SrcPtrInfo) const29 ARMSelectionDAGInfo::EmitTargetCodeForMemcpy(SelectionDAG &DAG, DebugLoc dl,
30 SDValue Chain,
31 SDValue Dst, SDValue Src,
32 SDValue Size, unsigned Align,
33 bool isVolatile, bool AlwaysInline,
34 MachinePointerInfo DstPtrInfo,
35 MachinePointerInfo SrcPtrInfo) const {
36 // Do repeated 4-byte loads and stores. To be improved.
37 // This requires 4-byte alignment.
38 if ((Align & 3) != 0)
39 return SDValue();
40 // This requires the copy size to be a constant, preferably
41 // within a subtarget-specific limit.
42 ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);
43 if (!ConstantSize)
44 return SDValue();
45 uint64_t SizeVal = ConstantSize->getZExtValue();
46 if (!AlwaysInline && SizeVal > Subtarget->getMaxInlineSizeThreshold())
47 return SDValue();
48
49 unsigned BytesLeft = SizeVal & 3;
50 unsigned NumMemOps = SizeVal >> 2;
51 unsigned EmittedNumMemOps = 0;
52 EVT VT = MVT::i32;
53 unsigned VTSize = 4;
54 unsigned i = 0;
55 const unsigned MAX_LOADS_IN_LDM = 6;
56 SDValue TFOps[MAX_LOADS_IN_LDM];
57 SDValue Loads[MAX_LOADS_IN_LDM];
58 uint64_t SrcOff = 0, DstOff = 0;
59
60 // Emit up to MAX_LOADS_IN_LDM loads, then a TokenFactor barrier, then the
61 // same number of stores. The loads and stores will get combined into
62 // ldm/stm later on.
63 while (EmittedNumMemOps < NumMemOps) {
64 for (i = 0;
65 i < MAX_LOADS_IN_LDM && EmittedNumMemOps + i < NumMemOps; ++i) {
66 Loads[i] = DAG.getLoad(VT, dl, Chain,
67 DAG.getNode(ISD::ADD, dl, MVT::i32, Src,
68 DAG.getConstant(SrcOff, MVT::i32)),
69 SrcPtrInfo.getWithOffset(SrcOff), isVolatile,
70 false, 0);
71 TFOps[i] = Loads[i].getValue(1);
72 SrcOff += VTSize;
73 }
74 Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, &TFOps[0], i);
75
76 for (i = 0;
77 i < MAX_LOADS_IN_LDM && EmittedNumMemOps + i < NumMemOps; ++i) {
78 TFOps[i] = DAG.getStore(Chain, dl, Loads[i],
79 DAG.getNode(ISD::ADD, dl, MVT::i32, Dst,
80 DAG.getConstant(DstOff, MVT::i32)),
81 DstPtrInfo.getWithOffset(DstOff),
82 isVolatile, false, 0);
83 DstOff += VTSize;
84 }
85 Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, &TFOps[0], i);
86
87 EmittedNumMemOps += i;
88 }
89
90 if (BytesLeft == 0)
91 return Chain;
92
93 // Issue loads / stores for the trailing (1 - 3) bytes.
94 unsigned BytesLeftSave = BytesLeft;
95 i = 0;
96 while (BytesLeft) {
97 if (BytesLeft >= 2) {
98 VT = MVT::i16;
99 VTSize = 2;
100 } else {
101 VT = MVT::i8;
102 VTSize = 1;
103 }
104
105 Loads[i] = DAG.getLoad(VT, dl, Chain,
106 DAG.getNode(ISD::ADD, dl, MVT::i32, Src,
107 DAG.getConstant(SrcOff, MVT::i32)),
108 SrcPtrInfo.getWithOffset(SrcOff), false, false, 0);
109 TFOps[i] = Loads[i].getValue(1);
110 ++i;
111 SrcOff += VTSize;
112 BytesLeft -= VTSize;
113 }
114 Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, &TFOps[0], i);
115
116 i = 0;
117 BytesLeft = BytesLeftSave;
118 while (BytesLeft) {
119 if (BytesLeft >= 2) {
120 VT = MVT::i16;
121 VTSize = 2;
122 } else {
123 VT = MVT::i8;
124 VTSize = 1;
125 }
126
127 TFOps[i] = DAG.getStore(Chain, dl, Loads[i],
128 DAG.getNode(ISD::ADD, dl, MVT::i32, Dst,
129 DAG.getConstant(DstOff, MVT::i32)),
130 DstPtrInfo.getWithOffset(DstOff), false, false, 0);
131 ++i;
132 DstOff += VTSize;
133 BytesLeft -= VTSize;
134 }
135 return DAG.getNode(ISD::TokenFactor, dl, MVT::Other, &TFOps[0], i);
136 }
137
138 // Adjust parameters for memset, EABI uses format (ptr, size, value),
139 // GNU library uses (ptr, value, size)
140 // See RTABI section 4.3.4
141 SDValue ARMSelectionDAGInfo::
EmitTargetCodeForMemset(SelectionDAG & DAG,DebugLoc dl,SDValue Chain,SDValue Dst,SDValue Src,SDValue Size,unsigned Align,bool isVolatile,MachinePointerInfo DstPtrInfo) const142 EmitTargetCodeForMemset(SelectionDAG &DAG, DebugLoc dl,
143 SDValue Chain, SDValue Dst,
144 SDValue Src, SDValue Size,
145 unsigned Align, bool isVolatile,
146 MachinePointerInfo DstPtrInfo) const {
147 // Use default for non AAPCS subtargets
148 if (!Subtarget->isAAPCS_ABI())
149 return SDValue();
150
151 const ARMTargetLowering &TLI =
152 *static_cast<const ARMTargetLowering*>(DAG.getTarget().getTargetLowering());
153 TargetLowering::ArgListTy Args;
154 TargetLowering::ArgListEntry Entry;
155
156 // First argument: data pointer
157 Type *IntPtrTy = TLI.getTargetData()->getIntPtrType(*DAG.getContext());
158 Entry.Node = Dst;
159 Entry.Ty = IntPtrTy;
160 Args.push_back(Entry);
161
162 // Second argument: buffer size
163 Entry.Node = Size;
164 Entry.Ty = IntPtrTy;
165 Entry.isSExt = false;
166 Args.push_back(Entry);
167
168 // Extend or truncate the argument to be an i32 value for the call.
169 if (Src.getValueType().bitsGT(MVT::i32))
170 Src = DAG.getNode(ISD::TRUNCATE, dl, MVT::i32, Src);
171 else
172 Src = DAG.getNode(ISD::ZERO_EXTEND, dl, MVT::i32, Src);
173
174 // Third argument: value to fill
175 Entry.Node = Src;
176 Entry.Ty = Type::getInt32Ty(*DAG.getContext());
177 Entry.isSExt = true;
178 Args.push_back(Entry);
179
180 // Emit __eabi_memset call
181 std::pair<SDValue,SDValue> CallResult =
182 TLI.LowerCallTo(Chain,
183 Type::getVoidTy(*DAG.getContext()), // return type
184 false, // return sign ext
185 false, // return zero ext
186 false, // is var arg
187 false, // is in regs
188 0, // number of fixed arguments
189 TLI.getLibcallCallingConv(RTLIB::MEMSET), // call conv
190 false, // is tail call
191 false, // is return val used
192 DAG.getExternalSymbol(TLI.getLibcallName(RTLIB::MEMSET),
193 TLI.getPointerTy()), // callee
194 Args, DAG, dl); // arg list, DAG and debug
195
196 return CallResult.second;
197 }
198