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 <deque>
19 
20 using namespace llvm;
21 
22 namespace {
23 class CallingConvEmitter {
24   RecordKeeper &Records;
25   unsigned Counter = 0u;
26   std::string CurrentAction;
27   bool SwiftAction = false;
28 
29   std::map<std::string, std::set<std::string>> AssignedRegsMap;
30   std::map<std::string, std::set<std::string>> AssignedSwiftRegsMap;
31   std::map<std::string, std::set<std::string>> DelegateToMap;
32 
33 public:
34   explicit CallingConvEmitter(RecordKeeper &R) : Records(R) {}
35 
36   void run(raw_ostream &o);
37 
38 private:
39   void EmitCallingConv(Record *CC, raw_ostream &O);
40   void EmitAction(Record *Action, unsigned Indent, raw_ostream &O);
41   void EmitArgRegisterLists(raw_ostream &O);
42 };
43 } // End anonymous namespace
44 
45 void CallingConvEmitter::run(raw_ostream &O) {
46   emitSourceFileHeader("Calling Convention Implementation Fragment", O);
47 
48   std::vector<Record *> CCs = Records.getAllDerivedDefinitions("CallingConv");
49 
50   // Emit prototypes for all of the non-custom CC's so that they can forward ref
51   // each other.
52   Records.startTimer("Emit prototypes");
53   O << "#ifndef GET_CC_REGISTER_LISTS\n\n";
54   for (Record *CC : CCs) {
55     if (!CC->getValueAsBit("Custom")) {
56       unsigned Pad = CC->getName().size();
57       if (CC->getValueAsBit("Entry")) {
58         O << "bool llvm::";
59         Pad += 12;
60       } else {
61         O << "static bool ";
62         Pad += 13;
63       }
64       O << CC->getName() << "(unsigned ValNo, MVT ValVT,\n"
65         << std::string(Pad, ' ') << "MVT LocVT, CCValAssign::LocInfo LocInfo,\n"
66         << std::string(Pad, ' ')
67         << "ISD::ArgFlagsTy ArgFlags, CCState &State);\n";
68     }
69   }
70 
71   // Emit each non-custom calling convention description in full.
72   Records.startTimer("Emit full descriptions");
73   for (Record *CC : CCs) {
74     if (!CC->getValueAsBit("Custom")) {
75       EmitCallingConv(CC, O);
76     }
77   }
78 
79   EmitArgRegisterLists(O);
80 
81   O << "\n#endif // CC_REGISTER_LIST\n";
82 }
83 
84 void CallingConvEmitter::EmitCallingConv(Record *CC, raw_ostream &O) {
85   ListInit *CCActions = CC->getValueAsListInit("Actions");
86   Counter = 0;
87 
88   CurrentAction = CC->getName().str();
89   // Call upon the creation of a map entry from the void!
90   // We want an entry in AssignedRegsMap for every action, even if that
91   // entry is empty.
92   AssignedRegsMap[CurrentAction] = {};
93 
94   O << "\n\n";
95   unsigned Pad = CurrentAction.size();
96   if (CC->getValueAsBit("Entry")) {
97     O << "bool llvm::";
98     Pad += 12;
99   } else {
100     O << "static bool ";
101     Pad += 13;
102   }
103   O << CurrentAction << "(unsigned ValNo, MVT ValVT,\n"
104     << std::string(Pad, ' ') << "MVT LocVT, CCValAssign::LocInfo LocInfo,\n"
105     << std::string(Pad, ' ') << "ISD::ArgFlagsTy ArgFlags, CCState &State) {\n";
106   // Emit all of the actions, in order.
107   for (unsigned i = 0, e = CCActions->size(); i != e; ++i) {
108     Record *Action = CCActions->getElementAsRecord(i);
109     SwiftAction = llvm::any_of(Action->getSuperClasses(),
110                                [](const std::pair<Record *, SMRange> &Class) {
111                                  std::string Name =
112                                      Class.first->getNameInitAsString();
113                                  return StringRef(Name).startswith("CCIfSwift");
114                                });
115 
116     O << "\n";
117     EmitAction(Action, 2, O);
118   }
119 
120   O << "\n  return true; // CC didn't match.\n";
121   O << "}\n";
122 }
123 
124 void CallingConvEmitter::EmitAction(Record *Action,
125                                     unsigned Indent, raw_ostream &O) {
126   std::string IndentStr = std::string(Indent, ' ');
127 
128   if (Action->isSubClassOf("CCPredicateAction")) {
129     O << IndentStr << "if (";
130 
131     if (Action->isSubClassOf("CCIfType")) {
132       ListInit *VTs = Action->getValueAsListInit("VTs");
133       for (unsigned i = 0, e = VTs->size(); i != e; ++i) {
134         Record *VT = VTs->getElementAsRecord(i);
135         if (i != 0) O << " ||\n    " << IndentStr;
136         O << "LocVT == " << getEnumName(getValueType(VT));
137       }
138 
139     } else if (Action->isSubClassOf("CCIf")) {
140       O << Action->getValueAsString("Predicate");
141     } else {
142       errs() << *Action;
143       PrintFatalError(Action->getLoc(), "Unknown CCPredicateAction!");
144     }
145 
146     O << ") {\n";
147     EmitAction(Action->getValueAsDef("SubAction"), Indent+2, O);
148     O << IndentStr << "}\n";
149   } else {
150     if (Action->isSubClassOf("CCDelegateTo")) {
151       Record *CC = Action->getValueAsDef("CC");
152       O << IndentStr << "if (!" << CC->getName()
153         << "(ValNo, ValVT, LocVT, LocInfo, ArgFlags, State))\n"
154         << IndentStr << "  return false;\n";
155       DelegateToMap[CurrentAction].insert(CC->getName().str());
156     } else if (Action->isSubClassOf("CCAssignToReg") ||
157                Action->isSubClassOf("CCAssignToRegAndStack")) {
158       ListInit *RegList = Action->getValueAsListInit("RegList");
159       if (RegList->size() == 1) {
160         std::string Name = getQualifiedName(RegList->getElementAsRecord(0));
161         O << IndentStr << "if (unsigned Reg = State.AllocateReg(" << Name
162           << ")) {\n";
163         if (SwiftAction)
164           AssignedSwiftRegsMap[CurrentAction].insert(Name);
165         else
166           AssignedRegsMap[CurrentAction].insert(Name);
167       } else {
168         O << IndentStr << "static const MCPhysReg RegList" << ++Counter
169           << "[] = {\n";
170         O << IndentStr << "  ";
171         ListSeparator LS;
172         for (unsigned i = 0, e = RegList->size(); i != e; ++i) {
173           std::string Name = getQualifiedName(RegList->getElementAsRecord(i));
174           if (SwiftAction)
175             AssignedSwiftRegsMap[CurrentAction].insert(Name);
176           else
177             AssignedRegsMap[CurrentAction].insert(Name);
178           O << LS << Name;
179         }
180         O << "\n" << IndentStr << "};\n";
181         O << IndentStr << "if (unsigned Reg = State.AllocateReg(RegList"
182           << Counter << ")) {\n";
183       }
184       O << IndentStr << "  State.addLoc(CCValAssign::getReg(ValNo, ValVT, "
185         << "Reg, LocVT, LocInfo));\n";
186       if (Action->isSubClassOf("CCAssignToRegAndStack")) {
187         int Size = Action->getValueAsInt("Size");
188         int Align = Action->getValueAsInt("Align");
189         O << IndentStr << "  (void)State.AllocateStack(";
190         if (Size)
191           O << Size << ", ";
192         else
193           O << "\n"
194             << IndentStr
195             << "  State.getMachineFunction().getDataLayout()."
196                "getTypeAllocSize(EVT(LocVT).getTypeForEVT(State.getContext())),"
197                " ";
198         if (Align)
199           O << "Align(" << Align << ")";
200         else
201           O << "\n"
202             << IndentStr
203             << "  State.getMachineFunction().getDataLayout()."
204                "getABITypeAlign(EVT(LocVT).getTypeForEVT(State.getContext()"
205                "))";
206         O << ");\n";
207       }
208       O << IndentStr << "  return false;\n";
209       O << IndentStr << "}\n";
210     } else if (Action->isSubClassOf("CCAssignToRegWithShadow")) {
211       ListInit *RegList = Action->getValueAsListInit("RegList");
212       ListInit *ShadowRegList = Action->getValueAsListInit("ShadowRegList");
213       if (!ShadowRegList->empty() && ShadowRegList->size() != RegList->size())
214         PrintFatalError(Action->getLoc(),
215                         "Invalid length of list of shadowed registers");
216 
217       if (RegList->size() == 1) {
218         O << IndentStr << "if (unsigned Reg = State.AllocateReg(";
219         O << getQualifiedName(RegList->getElementAsRecord(0));
220         O << ", " << getQualifiedName(ShadowRegList->getElementAsRecord(0));
221         O << ")) {\n";
222       } else {
223         unsigned RegListNumber = ++Counter;
224         unsigned ShadowRegListNumber = ++Counter;
225 
226         O << IndentStr << "static const MCPhysReg RegList" << RegListNumber
227           << "[] = {\n";
228         O << IndentStr << "  ";
229         ListSeparator LS;
230         for (unsigned i = 0, e = RegList->size(); i != e; ++i)
231           O << LS << getQualifiedName(RegList->getElementAsRecord(i));
232         O << "\n" << IndentStr << "};\n";
233 
234         O << IndentStr << "static const MCPhysReg RegList"
235           << ShadowRegListNumber << "[] = {\n";
236         O << IndentStr << "  ";
237         ListSeparator LSS;
238         for (unsigned i = 0, e = ShadowRegList->size(); i != e; ++i)
239           O << LSS << getQualifiedName(ShadowRegList->getElementAsRecord(i));
240         O << "\n" << IndentStr << "};\n";
241 
242         O << IndentStr << "if (unsigned Reg = State.AllocateReg(RegList"
243           << RegListNumber << ", " << "RegList" << ShadowRegListNumber
244           << ")) {\n";
245       }
246       O << IndentStr << "  State.addLoc(CCValAssign::getReg(ValNo, ValVT, "
247         << "Reg, LocVT, LocInfo));\n";
248       O << IndentStr << "  return false;\n";
249       O << IndentStr << "}\n";
250     } else if (Action->isSubClassOf("CCAssignToStack")) {
251       int Size = Action->getValueAsInt("Size");
252       int Align = Action->getValueAsInt("Align");
253 
254       O << IndentStr << "int64_t Offset" << ++Counter
255         << " = State.AllocateStack(";
256       if (Size)
257         O << Size << ", ";
258       else
259         O << "\n" << IndentStr
260           << "  State.getMachineFunction().getDataLayout()."
261              "getTypeAllocSize(EVT(LocVT).getTypeForEVT(State.getContext())),"
262              " ";
263       if (Align)
264         O << "Align(" << Align << ")";
265       else
266         O << "\n"
267           << IndentStr
268           << "  State.getMachineFunction().getDataLayout()."
269              "getABITypeAlign(EVT(LocVT).getTypeForEVT(State.getContext()"
270              "))";
271       O << ");\n" << IndentStr
272         << "State.addLoc(CCValAssign::getMem(ValNo, ValVT, Offset"
273         << Counter << ", LocVT, LocInfo));\n";
274       O << IndentStr << "return false;\n";
275     } else if (Action->isSubClassOf("CCAssignToStackWithShadow")) {
276       int Size = Action->getValueAsInt("Size");
277       int Align = Action->getValueAsInt("Align");
278       ListInit *ShadowRegList = Action->getValueAsListInit("ShadowRegList");
279 
280       unsigned ShadowRegListNumber = ++Counter;
281 
282       O << IndentStr << "static const MCPhysReg ShadowRegList"
283           << ShadowRegListNumber << "[] = {\n";
284       O << IndentStr << "  ";
285       ListSeparator LS;
286       for (unsigned i = 0, e = ShadowRegList->size(); i != e; ++i)
287         O << LS << getQualifiedName(ShadowRegList->getElementAsRecord(i));
288       O << "\n" << IndentStr << "};\n";
289 
290       O << IndentStr << "int64_t Offset" << ++Counter
291         << " = State.AllocateStack(" << Size << ", Align(" << Align << "), "
292         << "ShadowRegList" << ShadowRegListNumber << ");\n";
293       O << IndentStr << "State.addLoc(CCValAssign::getMem(ValNo, ValVT, Offset"
294         << Counter << ", LocVT, LocInfo));\n";
295       O << IndentStr << "return false;\n";
296     } else if (Action->isSubClassOf("CCPromoteToType")) {
297       Record *DestTy = Action->getValueAsDef("DestTy");
298       MVT::SimpleValueType DestVT = getValueType(DestTy);
299       O << IndentStr << "LocVT = " << getEnumName(DestVT) <<";\n";
300       if (MVT(DestVT).isFloatingPoint()) {
301         O << IndentStr << "LocInfo = CCValAssign::FPExt;\n";
302       } else {
303         O << IndentStr << "if (ArgFlags.isSExt())\n"
304           << IndentStr << "  LocInfo = CCValAssign::SExt;\n"
305           << IndentStr << "else if (ArgFlags.isZExt())\n"
306           << IndentStr << "  LocInfo = CCValAssign::ZExt;\n"
307           << IndentStr << "else\n"
308           << IndentStr << "  LocInfo = CCValAssign::AExt;\n";
309       }
310     } else if (Action->isSubClassOf("CCPromoteToUpperBitsInType")) {
311       Record *DestTy = Action->getValueAsDef("DestTy");
312       MVT::SimpleValueType DestVT = getValueType(DestTy);
313       O << IndentStr << "LocVT = " << getEnumName(DestVT) << ";\n";
314       if (MVT(DestVT).isFloatingPoint()) {
315         PrintFatalError(Action->getLoc(),
316                         "CCPromoteToUpperBitsInType does not handle floating "
317                         "point");
318       } else {
319         O << IndentStr << "if (ArgFlags.isSExt())\n"
320           << IndentStr << "  LocInfo = CCValAssign::SExtUpper;\n"
321           << IndentStr << "else if (ArgFlags.isZExt())\n"
322           << IndentStr << "  LocInfo = CCValAssign::ZExtUpper;\n"
323           << IndentStr << "else\n"
324           << IndentStr << "  LocInfo = CCValAssign::AExtUpper;\n";
325       }
326     } else if (Action->isSubClassOf("CCBitConvertToType")) {
327       Record *DestTy = Action->getValueAsDef("DestTy");
328       O << IndentStr << "LocVT = " << getEnumName(getValueType(DestTy)) <<";\n";
329       O << IndentStr << "LocInfo = CCValAssign::BCvt;\n";
330     } else if (Action->isSubClassOf("CCTruncToType")) {
331       Record *DestTy = Action->getValueAsDef("DestTy");
332       O << IndentStr << "LocVT = " << getEnumName(getValueType(DestTy)) <<";\n";
333       O << IndentStr << "LocInfo = CCValAssign::Trunc;\n";
334     } else if (Action->isSubClassOf("CCPassIndirect")) {
335       Record *DestTy = Action->getValueAsDef("DestTy");
336       O << IndentStr << "LocVT = " << getEnumName(getValueType(DestTy)) <<";\n";
337       O << IndentStr << "LocInfo = CCValAssign::Indirect;\n";
338     } else if (Action->isSubClassOf("CCPassByVal")) {
339       int Size = Action->getValueAsInt("Size");
340       int Align = Action->getValueAsInt("Align");
341       O << IndentStr << "State.HandleByVal(ValNo, ValVT, LocVT, LocInfo, "
342         << Size << ", Align(" << Align << "), ArgFlags);\n";
343       O << IndentStr << "return false;\n";
344     } else if (Action->isSubClassOf("CCCustom")) {
345       O << IndentStr
346         << "if (" << Action->getValueAsString("FuncName") << "(ValNo, ValVT, "
347         << "LocVT, LocInfo, ArgFlags, State))\n";
348       O << IndentStr << "  return false;\n";
349     } else {
350       errs() << *Action;
351       PrintFatalError(Action->getLoc(), "Unknown CCAction!");
352     }
353   }
354 }
355 
356 void CallingConvEmitter::EmitArgRegisterLists(raw_ostream &O) {
357   // Transitively merge all delegated CCs into AssignedRegsMap.
358   using EntryTy = std::pair<std::string, std::set<std::string>>;
359   bool Redo;
360   do {
361     Redo = false;
362     std::deque<EntryTy> Worklist(DelegateToMap.begin(), DelegateToMap.end());
363 
364     while (!Worklist.empty()) {
365       EntryTy Entry = Worklist.front();
366       Worklist.pop_front();
367 
368       const std::string &CCName = Entry.first;
369       std::set<std::string> &Registers = Entry.second;
370       if (!Registers.empty())
371         continue;
372 
373       for (auto &InnerEntry : Worklist) {
374         const std::string &InnerCCName = InnerEntry.first;
375         std::set<std::string> &InnerRegisters = InnerEntry.second;
376 
377         if (InnerRegisters.find(CCName) != InnerRegisters.end()) {
378           AssignedRegsMap[InnerCCName].insert(
379               AssignedRegsMap[CCName].begin(),
380               AssignedRegsMap[CCName].end());
381           InnerRegisters.erase(CCName);
382         }
383       }
384 
385       DelegateToMap.erase(CCName);
386       Redo = true;
387     }
388   } while (Redo);
389 
390   if (AssignedRegsMap.empty())
391     return;
392 
393   O << "\n#else\n\n";
394 
395   for (auto &Entry : AssignedRegsMap) {
396     const std::string &RegName = Entry.first;
397     std::set<std::string> &Registers = Entry.second;
398 
399     if (RegName.empty())
400       continue;
401 
402     O << "const MCRegister " << Entry.first << "_ArgRegs[] = { ";
403 
404     if (Registers.empty()) {
405       O << "0";
406     } else {
407       ListSeparator LS;
408       for (const std::string &Reg : Registers)
409         O << LS << Reg;
410     }
411 
412     O << " };\n";
413   }
414 
415   if (AssignedSwiftRegsMap.empty())
416     return;
417 
418   O << "\n// Registers used by Swift.\n";
419   for (auto &Entry : AssignedSwiftRegsMap) {
420     const std::string &RegName = Entry.first;
421     std::set<std::string> &Registers = Entry.second;
422 
423     O << "const MCRegister " << RegName << "_Swift_ArgRegs[] = { ";
424 
425     ListSeparator LS;
426     for (const std::string &Reg : Registers)
427       O << LS << Reg;
428 
429     O << " };\n";
430   }
431 }
432 
433 static TableGen::Emitter::OptClass<CallingConvEmitter>
434     X("gen-callingconv", "Generate calling convention descriptions");
435