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 #include <cassert>
19 using namespace llvm;
20 
21 namespace {
22 class CallingConvEmitter {
23   RecordKeeper &Records;
24 public:
25   explicit CallingConvEmitter(RecordKeeper &R) : Records(R) {}
26 
27   void run(raw_ostream &o);
28 
29 private:
30   void EmitCallingConv(Record *CC, raw_ostream &O);
31   void EmitAction(Record *Action, unsigned Indent, raw_ostream &O);
32   unsigned Counter;
33 };
34 } // End anonymous namespace
35 
36 void CallingConvEmitter::run(raw_ostream &O) {
37   std::vector<Record*> CCs = Records.getAllDerivedDefinitions("CallingConv");
38 
39   // Emit prototypes for all of the non-custom CC's so that they can forward ref
40   // each other.
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   for (Record *CC : CCs) {
60     if (!CC->getValueAsBit("Custom"))
61       EmitCallingConv(CC, O);
62   }
63 }
64 
65 
66 void CallingConvEmitter::EmitCallingConv(Record *CC, raw_ostream &O) {
67   ListInit *CCActions = CC->getValueAsListInit("Actions");
68   Counter = 0;
69 
70   O << "\n\n";
71   unsigned Pad = CC->getName().size();
72   if (CC->getValueAsBit("Entry")) {
73     O << "bool llvm::";
74     Pad += 12;
75   } else {
76     O << "static bool ";
77     Pad += 13;
78   }
79   O << CC->getName() << "(unsigned ValNo, MVT ValVT,\n"
80     << std::string(Pad, ' ') << "MVT LocVT, CCValAssign::LocInfo LocInfo,\n"
81     << std::string(Pad, ' ') << "ISD::ArgFlagsTy ArgFlags, CCState &State) {\n";
82   // Emit all of the actions, in order.
83   for (unsigned i = 0, e = CCActions->size(); i != e; ++i) {
84     O << "\n";
85     EmitAction(CCActions->getElementAsRecord(i), 2, O);
86   }
87 
88   O << "\n  return true;  // CC didn't match.\n";
89   O << "}\n";
90 }
91 
92 void CallingConvEmitter::EmitAction(Record *Action,
93                                     unsigned Indent, raw_ostream &O) {
94   std::string IndentStr = std::string(Indent, ' ');
95 
96   if (Action->isSubClassOf("CCPredicateAction")) {
97     O << IndentStr << "if (";
98 
99     if (Action->isSubClassOf("CCIfType")) {
100       ListInit *VTs = Action->getValueAsListInit("VTs");
101       for (unsigned i = 0, e = VTs->size(); i != e; ++i) {
102         Record *VT = VTs->getElementAsRecord(i);
103         if (i != 0) O << " ||\n    " << IndentStr;
104         O << "LocVT == " << getEnumName(getValueType(VT));
105       }
106 
107     } else if (Action->isSubClassOf("CCIf")) {
108       O << Action->getValueAsString("Predicate");
109     } else {
110       errs() << *Action;
111       PrintFatalError("Unknown CCPredicateAction!");
112     }
113 
114     O << ") {\n";
115     EmitAction(Action->getValueAsDef("SubAction"), Indent+2, O);
116     O << IndentStr << "}\n";
117   } else {
118     if (Action->isSubClassOf("CCDelegateTo")) {
119       Record *CC = Action->getValueAsDef("CC");
120       O << IndentStr << "if (!" << CC->getName()
121         << "(ValNo, ValVT, LocVT, LocInfo, ArgFlags, State))\n"
122         << IndentStr << "  return false;\n";
123     } else if (Action->isSubClassOf("CCAssignToReg")) {
124       ListInit *RegList = Action->getValueAsListInit("RegList");
125       if (RegList->size() == 1) {
126         O << IndentStr << "if (unsigned Reg = State.AllocateReg(";
127         O << getQualifiedName(RegList->getElementAsRecord(0)) << ")) {\n";
128       } else {
129         O << IndentStr << "static const MCPhysReg RegList" << ++Counter
130           << "[] = {\n";
131         O << IndentStr << "  ";
132         for (unsigned i = 0, e = RegList->size(); i != e; ++i) {
133           if (i != 0) O << ", ";
134           O << getQualifiedName(RegList->getElementAsRecord(i));
135         }
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("Invalid length of list of shadowed registers");
149 
150       if (RegList->size() == 1) {
151         O << IndentStr << "if (unsigned Reg = State.AllocateReg(";
152         O << getQualifiedName(RegList->getElementAsRecord(0));
153         O << ", " << getQualifiedName(ShadowRegList->getElementAsRecord(0));
154         O << ")) {\n";
155       } else {
156         unsigned RegListNumber = ++Counter;
157         unsigned ShadowRegListNumber = ++Counter;
158 
159         O << IndentStr << "static const MCPhysReg RegList" << RegListNumber
160           << "[] = {\n";
161         O << IndentStr << "  ";
162         for (unsigned i = 0, e = RegList->size(); i != e; ++i) {
163           if (i != 0) O << ", ";
164           O << getQualifiedName(RegList->getElementAsRecord(i));
165         }
166         O << "\n" << IndentStr << "};\n";
167 
168         O << IndentStr << "static const MCPhysReg RegList"
169           << ShadowRegListNumber << "[] = {\n";
170         O << IndentStr << "  ";
171         for (unsigned i = 0, e = ShadowRegList->size(); i != e; ++i) {
172           if (i != 0) O << ", ";
173           O << getQualifiedName(ShadowRegList->getElementAsRecord(i));
174         }
175         O << "\n" << IndentStr << "};\n";
176 
177         O << IndentStr << "if (unsigned Reg = State.AllocateReg(RegList"
178           << RegListNumber << ", " << "RegList" << ShadowRegListNumber
179           << ")) {\n";
180       }
181       O << IndentStr << "  State.addLoc(CCValAssign::getReg(ValNo, ValVT, "
182         << "Reg, LocVT, LocInfo));\n";
183       O << IndentStr << "  return false;\n";
184       O << IndentStr << "}\n";
185     } else if (Action->isSubClassOf("CCAssignToStack")) {
186       int Size = Action->getValueAsInt("Size");
187       int Align = Action->getValueAsInt("Align");
188 
189       O << IndentStr << "unsigned Offset" << ++Counter
190         << " = State.AllocateStack(";
191       if (Size)
192         O << Size << ", ";
193       else
194         O << "\n" << IndentStr
195           << "  State.getMachineFunction().getDataLayout()."
196              "getTypeAllocSize(EVT(LocVT).getTypeForEVT(State.getContext())),"
197              " ";
198       if (Align)
199         O << Align;
200       else
201         O << "\n" << IndentStr
202           << "  State.getMachineFunction().getDataLayout()."
203              "getABITypeAlignment(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       for (unsigned i = 0, e = ShadowRegList->size(); i != e; ++i) {
220         if (i != 0) O << ", ";
221         O << getQualifiedName(ShadowRegList->getElementAsRecord(i));
222       }
223       O << "\n" << IndentStr << "};\n";
224 
225       O << IndentStr << "unsigned Offset" << ++Counter
226         << " = State.AllocateStack("
227         << Size << ", " << Align << ", "
228         << "ShadowRegList" << ShadowRegListNumber << ");\n";
229       O << IndentStr << "State.addLoc(CCValAssign::getMem(ValNo, ValVT, Offset"
230         << Counter << ", LocVT, LocInfo));\n";
231       O << IndentStr << "return false;\n";
232     } else if (Action->isSubClassOf("CCPromoteToType")) {
233       Record *DestTy = Action->getValueAsDef("DestTy");
234       MVT::SimpleValueType DestVT = getValueType(DestTy);
235       O << IndentStr << "LocVT = " << getEnumName(DestVT) <<";\n";
236       if (MVT(DestVT).isFloatingPoint()) {
237         O << IndentStr << "LocInfo = CCValAssign::FPExt;\n";
238       } else {
239         O << IndentStr << "if (ArgFlags.isSExt())\n"
240           << IndentStr << IndentStr << "LocInfo = CCValAssign::SExt;\n"
241           << IndentStr << "else if (ArgFlags.isZExt())\n"
242           << IndentStr << IndentStr << "LocInfo = CCValAssign::ZExt;\n"
243           << IndentStr << "else\n"
244           << IndentStr << IndentStr << "LocInfo = CCValAssign::AExt;\n";
245       }
246     } else if (Action->isSubClassOf("CCPromoteToUpperBitsInType")) {
247       Record *DestTy = Action->getValueAsDef("DestTy");
248       MVT::SimpleValueType DestVT = getValueType(DestTy);
249       O << IndentStr << "LocVT = " << getEnumName(DestVT) << ";\n";
250       if (MVT(DestVT).isFloatingPoint()) {
251         PrintFatalError("CCPromoteToUpperBitsInType does not handle floating "
252                         "point");
253       } else {
254         O << IndentStr << "if (ArgFlags.isSExt())\n"
255           << IndentStr << IndentStr << "LocInfo = CCValAssign::SExtUpper;\n"
256           << IndentStr << "else if (ArgFlags.isZExt())\n"
257           << IndentStr << IndentStr << "LocInfo = CCValAssign::ZExtUpper;\n"
258           << IndentStr << "else\n"
259           << IndentStr << IndentStr << "LocInfo = CCValAssign::AExtUpper;\n";
260       }
261     } else if (Action->isSubClassOf("CCBitConvertToType")) {
262       Record *DestTy = Action->getValueAsDef("DestTy");
263       O << IndentStr << "LocVT = " << getEnumName(getValueType(DestTy)) <<";\n";
264       O << IndentStr << "LocInfo = CCValAssign::BCvt;\n";
265     } else if (Action->isSubClassOf("CCPassIndirect")) {
266       Record *DestTy = Action->getValueAsDef("DestTy");
267       O << IndentStr << "LocVT = " << getEnumName(getValueType(DestTy)) <<";\n";
268       O << IndentStr << "LocInfo = CCValAssign::Indirect;\n";
269     } else if (Action->isSubClassOf("CCPassByVal")) {
270       int Size = Action->getValueAsInt("Size");
271       int Align = Action->getValueAsInt("Align");
272       O << IndentStr
273         << "State.HandleByVal(ValNo, ValVT, LocVT, LocInfo, "
274         << Size << ", " << Align << ", ArgFlags);\n";
275       O << IndentStr << "return false;\n";
276     } else if (Action->isSubClassOf("CCCustom")) {
277       O << IndentStr
278         << "if (" << Action->getValueAsString("FuncName") << "(ValNo, ValVT, "
279         << "LocVT, LocInfo, ArgFlags, State))\n";
280       O << IndentStr << IndentStr << "return false;\n";
281     } else {
282       errs() << *Action;
283       PrintFatalError("Unknown CCAction!");
284     }
285   }
286 }
287 
288 namespace llvm {
289 
290 void EmitCallingConv(RecordKeeper &RK, raw_ostream &OS) {
291   emitSourceFileHeader("Calling Convention Implementation Fragment", OS);
292   CallingConvEmitter(RK).run(OS);
293 }
294 
295 } // End llvm namespace
296