1 //===- CallingConvEmitter.cpp - Generate calling conventions --------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This tablegen backend is responsible for emitting descriptions of the calling
10 // conventions supported by this target.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "CodeGenTarget.h"
15 #include "llvm/TableGen/Error.h"
16 #include "llvm/TableGen/Record.h"
17 #include "llvm/TableGen/TableGenBackend.h"
18 using namespace llvm;
19 
20 namespace {
21 class CallingConvEmitter {
22   RecordKeeper &Records;
23 public:
24   explicit CallingConvEmitter(RecordKeeper &R) : Records(R) {}
25 
26   void run(raw_ostream &o);
27 
28 private:
29   void EmitCallingConv(Record *CC, raw_ostream &O);
30   void EmitAction(Record *Action, unsigned Indent, raw_ostream &O);
31   unsigned Counter;
32 };
33 } // End anonymous namespace
34 
35 void CallingConvEmitter::run(raw_ostream &O) {
36   std::vector<Record*> CCs = Records.getAllDerivedDefinitions("CallingConv");
37 
38   // Emit prototypes for all of the non-custom CC's so that they can forward ref
39   // each other.
40   Records.startTimer("Emit prototypes");
41   for (Record *CC : CCs) {
42     if (!CC->getValueAsBit("Custom")) {
43       unsigned Pad = CC->getName().size();
44       if (CC->getValueAsBit("Entry")) {
45         O << "bool llvm::";
46         Pad += 12;
47       } else {
48         O << "static bool ";
49         Pad += 13;
50       }
51       O << CC->getName() << "(unsigned ValNo, MVT ValVT,\n"
52         << std::string(Pad, ' ') << "MVT LocVT, CCValAssign::LocInfo LocInfo,\n"
53         << std::string(Pad, ' ')
54         << "ISD::ArgFlagsTy ArgFlags, CCState &State);\n";
55     }
56   }
57 
58   // Emit each non-custom calling convention description in full.
59   Records.startTimer("Emit full descriptions");
60   for (Record *CC : CCs) {
61     if (!CC->getValueAsBit("Custom"))
62       EmitCallingConv(CC, O);
63   }
64 }
65 
66 
67 void CallingConvEmitter::EmitCallingConv(Record *CC, raw_ostream &O) {
68   ListInit *CCActions = CC->getValueAsListInit("Actions");
69   Counter = 0;
70 
71   O << "\n\n";
72   unsigned Pad = CC->getName().size();
73   if (CC->getValueAsBit("Entry")) {
74     O << "bool llvm::";
75     Pad += 12;
76   } else {
77     O << "static bool ";
78     Pad += 13;
79   }
80   O << CC->getName() << "(unsigned ValNo, MVT ValVT,\n"
81     << std::string(Pad, ' ') << "MVT LocVT, CCValAssign::LocInfo LocInfo,\n"
82     << std::string(Pad, ' ') << "ISD::ArgFlagsTy ArgFlags, CCState &State) {\n";
83   // Emit all of the actions, in order.
84   for (unsigned i = 0, e = CCActions->size(); i != e; ++i) {
85     O << "\n";
86     EmitAction(CCActions->getElementAsRecord(i), 2, O);
87   }
88 
89   O << "\n  return true; // CC didn't match.\n";
90   O << "}\n";
91 }
92 
93 void CallingConvEmitter::EmitAction(Record *Action,
94                                     unsigned Indent, raw_ostream &O) {
95   std::string IndentStr = std::string(Indent, ' ');
96 
97   if (Action->isSubClassOf("CCPredicateAction")) {
98     O << IndentStr << "if (";
99 
100     if (Action->isSubClassOf("CCIfType")) {
101       ListInit *VTs = Action->getValueAsListInit("VTs");
102       for (unsigned i = 0, e = VTs->size(); i != e; ++i) {
103         Record *VT = VTs->getElementAsRecord(i);
104         if (i != 0) O << " ||\n    " << IndentStr;
105         O << "LocVT == " << getEnumName(getValueType(VT));
106       }
107 
108     } else if (Action->isSubClassOf("CCIf")) {
109       O << Action->getValueAsString("Predicate");
110     } else {
111       errs() << *Action;
112       PrintFatalError(Action->getLoc(), "Unknown CCPredicateAction!");
113     }
114 
115     O << ") {\n";
116     EmitAction(Action->getValueAsDef("SubAction"), Indent+2, O);
117     O << IndentStr << "}\n";
118   } else {
119     if (Action->isSubClassOf("CCDelegateTo")) {
120       Record *CC = Action->getValueAsDef("CC");
121       O << IndentStr << "if (!" << CC->getName()
122         << "(ValNo, ValVT, LocVT, LocInfo, ArgFlags, State))\n"
123         << IndentStr << "  return false;\n";
124     } else if (Action->isSubClassOf("CCAssignToReg")) {
125       ListInit *RegList = Action->getValueAsListInit("RegList");
126       if (RegList->size() == 1) {
127         O << IndentStr << "if (unsigned Reg = State.AllocateReg(";
128         O << getQualifiedName(RegList->getElementAsRecord(0)) << ")) {\n";
129       } else {
130         O << IndentStr << "static const MCPhysReg RegList" << ++Counter
131           << "[] = {\n";
132         O << IndentStr << "  ";
133         ListSeparator LS;
134         for (unsigned i = 0, e = RegList->size(); i != e; ++i)
135           O << LS << getQualifiedName(RegList->getElementAsRecord(i));
136         O << "\n" << IndentStr << "};\n";
137         O << IndentStr << "if (unsigned Reg = State.AllocateReg(RegList"
138           << Counter << ")) {\n";
139       }
140       O << IndentStr << "  State.addLoc(CCValAssign::getReg(ValNo, ValVT, "
141         << "Reg, LocVT, LocInfo));\n";
142       O << IndentStr << "  return false;\n";
143       O << IndentStr << "}\n";
144     } else if (Action->isSubClassOf("CCAssignToRegWithShadow")) {
145       ListInit *RegList = Action->getValueAsListInit("RegList");
146       ListInit *ShadowRegList = Action->getValueAsListInit("ShadowRegList");
147       if (!ShadowRegList->empty() && ShadowRegList->size() != RegList->size())
148         PrintFatalError(Action->getLoc(),
149                         "Invalid length of list of shadowed registers");
150 
151       if (RegList->size() == 1) {
152         O << IndentStr << "if (unsigned Reg = State.AllocateReg(";
153         O << getQualifiedName(RegList->getElementAsRecord(0));
154         O << ", " << getQualifiedName(ShadowRegList->getElementAsRecord(0));
155         O << ")) {\n";
156       } else {
157         unsigned RegListNumber = ++Counter;
158         unsigned ShadowRegListNumber = ++Counter;
159 
160         O << IndentStr << "static const MCPhysReg RegList" << RegListNumber
161           << "[] = {\n";
162         O << IndentStr << "  ";
163         ListSeparator LS;
164         for (unsigned i = 0, e = RegList->size(); i != e; ++i)
165           O << LS << getQualifiedName(RegList->getElementAsRecord(i));
166         O << "\n" << IndentStr << "};\n";
167 
168         O << IndentStr << "static const MCPhysReg RegList"
169           << ShadowRegListNumber << "[] = {\n";
170         O << IndentStr << "  ";
171         ListSeparator LSS;
172         for (unsigned i = 0, e = ShadowRegList->size(); i != e; ++i)
173           O << LSS << getQualifiedName(ShadowRegList->getElementAsRecord(i));
174         O << "\n" << IndentStr << "};\n";
175 
176         O << IndentStr << "if (unsigned Reg = State.AllocateReg(RegList"
177           << RegListNumber << ", " << "RegList" << ShadowRegListNumber
178           << ")) {\n";
179       }
180       O << IndentStr << "  State.addLoc(CCValAssign::getReg(ValNo, ValVT, "
181         << "Reg, LocVT, LocInfo));\n";
182       O << IndentStr << "  return false;\n";
183       O << IndentStr << "}\n";
184     } else if (Action->isSubClassOf("CCAssignToStack")) {
185       int Size = Action->getValueAsInt("Size");
186       int Align = Action->getValueAsInt("Align");
187 
188       O << IndentStr << "unsigned Offset" << ++Counter
189         << " = State.AllocateStack(";
190       if (Size)
191         O << Size << ", ";
192       else
193         O << "\n" << IndentStr
194           << "  State.getMachineFunction().getDataLayout()."
195              "getTypeAllocSize(EVT(LocVT).getTypeForEVT(State.getContext())),"
196              " ";
197       if (Align)
198         O << "Align(" << Align << ")";
199       else
200         O << "\n"
201           << IndentStr
202           << "  State.getMachineFunction().getDataLayout()."
203              "getABITypeAlign(EVT(LocVT).getTypeForEVT(State.getContext()"
204              "))";
205       O << ");\n" << IndentStr
206         << "State.addLoc(CCValAssign::getMem(ValNo, ValVT, Offset"
207         << Counter << ", LocVT, LocInfo));\n";
208       O << IndentStr << "return false;\n";
209     } else if (Action->isSubClassOf("CCAssignToStackWithShadow")) {
210       int Size = Action->getValueAsInt("Size");
211       int Align = Action->getValueAsInt("Align");
212       ListInit *ShadowRegList = Action->getValueAsListInit("ShadowRegList");
213 
214       unsigned ShadowRegListNumber = ++Counter;
215 
216       O << IndentStr << "static const MCPhysReg ShadowRegList"
217           << ShadowRegListNumber << "[] = {\n";
218       O << IndentStr << "  ";
219       ListSeparator LS;
220       for (unsigned i = 0, e = ShadowRegList->size(); i != e; ++i)
221         O << LS << getQualifiedName(ShadowRegList->getElementAsRecord(i));
222       O << "\n" << IndentStr << "};\n";
223 
224       O << IndentStr << "unsigned Offset" << ++Counter
225         << " = State.AllocateStack(" << Size << ", Align(" << Align << "), "
226         << "ShadowRegList" << ShadowRegListNumber << ");\n";
227       O << IndentStr << "State.addLoc(CCValAssign::getMem(ValNo, ValVT, Offset"
228         << Counter << ", LocVT, LocInfo));\n";
229       O << IndentStr << "return false;\n";
230     } else if (Action->isSubClassOf("CCPromoteToType")) {
231       Record *DestTy = Action->getValueAsDef("DestTy");
232       MVT::SimpleValueType DestVT = getValueType(DestTy);
233       O << IndentStr << "LocVT = " << getEnumName(DestVT) <<";\n";
234       if (MVT(DestVT).isFloatingPoint()) {
235         O << IndentStr << "LocInfo = CCValAssign::FPExt;\n";
236       } else {
237         O << IndentStr << "if (ArgFlags.isSExt())\n"
238           << IndentStr << "  LocInfo = CCValAssign::SExt;\n"
239           << IndentStr << "else if (ArgFlags.isZExt())\n"
240           << IndentStr << "  LocInfo = CCValAssign::ZExt;\n"
241           << IndentStr << "else\n"
242           << IndentStr << "  LocInfo = CCValAssign::AExt;\n";
243       }
244     } else if (Action->isSubClassOf("CCPromoteToUpperBitsInType")) {
245       Record *DestTy = Action->getValueAsDef("DestTy");
246       MVT::SimpleValueType DestVT = getValueType(DestTy);
247       O << IndentStr << "LocVT = " << getEnumName(DestVT) << ";\n";
248       if (MVT(DestVT).isFloatingPoint()) {
249         PrintFatalError(Action->getLoc(),
250                         "CCPromoteToUpperBitsInType does not handle floating "
251                         "point");
252       } else {
253         O << IndentStr << "if (ArgFlags.isSExt())\n"
254           << IndentStr << "  LocInfo = CCValAssign::SExtUpper;\n"
255           << IndentStr << "else if (ArgFlags.isZExt())\n"
256           << IndentStr << "  LocInfo = CCValAssign::ZExtUpper;\n"
257           << IndentStr << "else\n"
258           << IndentStr << "  LocInfo = CCValAssign::AExtUpper;\n";
259       }
260     } else if (Action->isSubClassOf("CCBitConvertToType")) {
261       Record *DestTy = Action->getValueAsDef("DestTy");
262       O << IndentStr << "LocVT = " << getEnumName(getValueType(DestTy)) <<";\n";
263       O << IndentStr << "LocInfo = CCValAssign::BCvt;\n";
264     } else if (Action->isSubClassOf("CCTruncToType")) {
265       Record *DestTy = Action->getValueAsDef("DestTy");
266       O << IndentStr << "LocVT = " << getEnumName(getValueType(DestTy)) <<";\n";
267       O << IndentStr << "LocInfo = CCValAssign::Trunc;\n";
268     } else if (Action->isSubClassOf("CCPassIndirect")) {
269       Record *DestTy = Action->getValueAsDef("DestTy");
270       O << IndentStr << "LocVT = " << getEnumName(getValueType(DestTy)) <<";\n";
271       O << IndentStr << "LocInfo = CCValAssign::Indirect;\n";
272     } else if (Action->isSubClassOf("CCPassByVal")) {
273       int Size = Action->getValueAsInt("Size");
274       int Align = Action->getValueAsInt("Align");
275       O << IndentStr << "State.HandleByVal(ValNo, ValVT, LocVT, LocInfo, "
276         << Size << ", Align(" << Align << "), ArgFlags);\n";
277       O << IndentStr << "return false;\n";
278     } else if (Action->isSubClassOf("CCCustom")) {
279       O << IndentStr
280         << "if (" << Action->getValueAsString("FuncName") << "(ValNo, ValVT, "
281         << "LocVT, LocInfo, ArgFlags, State))\n";
282       O << IndentStr << "  return false;\n";
283     } else {
284       errs() << *Action;
285       PrintFatalError(Action->getLoc(), "Unknown CCAction!");
286     }
287   }
288 }
289 
290 namespace llvm {
291 
292 void EmitCallingConv(RecordKeeper &RK, raw_ostream &OS) {
293   emitSourceFileHeader("Calling Convention Implementation Fragment", OS);
294   CallingConvEmitter(RK).run(OS);
295 }
296 
297 } // End llvm namespace
298