1 //===-- XCoreAsmPrinter.cpp - XCore LLVM assembly writer ------------------===//
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 file contains a printer that converts from our internal representation
10 // of machine-dependent LLVM code to the XAS-format XCore assembly language.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "InstPrinter/XCoreInstPrinter.h"
15 #include "XCore.h"
16 #include "XCoreInstrInfo.h"
17 #include "XCoreMCInstLower.h"
18 #include "XCoreSubtarget.h"
19 #include "XCoreTargetMachine.h"
20 #include "XCoreTargetStreamer.h"
21 #include "llvm/ADT/SmallString.h"
22 #include "llvm/ADT/StringExtras.h"
23 #include "llvm/CodeGen/AsmPrinter.h"
24 #include "llvm/CodeGen/MachineConstantPool.h"
25 #include "llvm/CodeGen/MachineFunctionPass.h"
26 #include "llvm/CodeGen/MachineInstr.h"
27 #include "llvm/CodeGen/MachineJumpTableInfo.h"
28 #include "llvm/CodeGen/MachineModuleInfo.h"
29 #include "llvm/IR/Constants.h"
30 #include "llvm/IR/DataLayout.h"
31 #include "llvm/IR/DebugInfo.h"
32 #include "llvm/IR/DerivedTypes.h"
33 #include "llvm/IR/Mangler.h"
34 #include "llvm/IR/Module.h"
35 #include "llvm/MC/MCAsmInfo.h"
36 #include "llvm/MC/MCExpr.h"
37 #include "llvm/MC/MCInst.h"
38 #include "llvm/MC/MCStreamer.h"
39 #include "llvm/MC/MCSymbolELF.h"
40 #include "llvm/Support/ErrorHandling.h"
41 #include "llvm/Support/TargetRegistry.h"
42 #include "llvm/Support/raw_ostream.h"
43 #include "llvm/Target/TargetLoweringObjectFile.h"
44 #include <algorithm>
45 #include <cctype>
46 using namespace llvm;
47 
48 #define DEBUG_TYPE "asm-printer"
49 
50 namespace {
51   class XCoreAsmPrinter : public AsmPrinter {
52     XCoreMCInstLower MCInstLowering;
53     XCoreTargetStreamer &getTargetStreamer();
54 
55   public:
56     explicit XCoreAsmPrinter(TargetMachine &TM,
57                              std::unique_ptr<MCStreamer> Streamer)
58         : AsmPrinter(TM, std::move(Streamer)), MCInstLowering(*this) {}
59 
60     StringRef getPassName() const override { return "XCore Assembly Printer"; }
61 
62     void printInlineJT(const MachineInstr *MI, int opNum, raw_ostream &O,
63                        const std::string &directive = ".jmptable");
64     void printInlineJT32(const MachineInstr *MI, int opNum, raw_ostream &O) {
65       printInlineJT(MI, opNum, O, ".jmptable32");
66     }
67     void printOperand(const MachineInstr *MI, int opNum, raw_ostream &O);
68     bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
69                          unsigned AsmVariant, const char *ExtraCode,
70                          raw_ostream &O) override;
71     bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNum,
72                                unsigned AsmVariant, const char *ExtraCode,
73                                raw_ostream &O) override;
74 
75     void emitArrayBound(MCSymbol *Sym, const GlobalVariable *GV);
76     void EmitGlobalVariable(const GlobalVariable *GV) override;
77 
78     void EmitFunctionEntryLabel() override;
79     void EmitInstruction(const MachineInstr *MI) override;
80     void EmitFunctionBodyStart() override;
81     void EmitFunctionBodyEnd() override;
82   };
83 } // end of anonymous namespace
84 
85 XCoreTargetStreamer &XCoreAsmPrinter::getTargetStreamer() {
86   return static_cast<XCoreTargetStreamer&>(*OutStreamer->getTargetStreamer());
87 }
88 
89 void XCoreAsmPrinter::emitArrayBound(MCSymbol *Sym, const GlobalVariable *GV) {
90   assert( ( GV->hasExternalLinkage() || GV->hasWeakLinkage() ||
91             GV->hasLinkOnceLinkage() || GV->hasCommonLinkage() ) &&
92           "Unexpected linkage");
93   if (ArrayType *ATy = dyn_cast<ArrayType>(GV->getValueType())) {
94 
95     MCSymbol *SymGlob = OutContext.getOrCreateSymbol(
96                           Twine(Sym->getName() + StringRef(".globound")));
97     OutStreamer->EmitSymbolAttribute(SymGlob, MCSA_Global);
98     OutStreamer->EmitAssignment(SymGlob,
99                                 MCConstantExpr::create(ATy->getNumElements(),
100                                                        OutContext));
101     if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
102         GV->hasCommonLinkage()) {
103       OutStreamer->EmitSymbolAttribute(SymGlob, MCSA_Weak);
104     }
105   }
106 }
107 
108 void XCoreAsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
109   // Check to see if this is a special global used by LLVM, if so, emit it.
110   if (!GV->hasInitializer() ||
111       EmitSpecialLLVMGlobal(GV))
112     return;
113 
114   const DataLayout &DL = getDataLayout();
115   OutStreamer->SwitchSection(getObjFileLowering().SectionForGlobal(GV, TM));
116 
117   MCSymbol *GVSym = getSymbol(GV);
118   const Constant *C = GV->getInitializer();
119   unsigned Align = (unsigned)DL.getPreferredTypeAlignmentShift(C->getType());
120 
121   // Mark the start of the global
122   getTargetStreamer().emitCCTopData(GVSym->getName());
123 
124   switch (GV->getLinkage()) {
125   case GlobalValue::AppendingLinkage:
126     report_fatal_error("AppendingLinkage is not supported by this target!");
127   case GlobalValue::LinkOnceAnyLinkage:
128   case GlobalValue::LinkOnceODRLinkage:
129   case GlobalValue::WeakAnyLinkage:
130   case GlobalValue::WeakODRLinkage:
131   case GlobalValue::ExternalLinkage:
132   case GlobalValue::CommonLinkage:
133     emitArrayBound(GVSym, GV);
134     OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
135 
136     if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
137         GV->hasCommonLinkage())
138       OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Weak);
139     LLVM_FALLTHROUGH;
140   case GlobalValue::InternalLinkage:
141   case GlobalValue::PrivateLinkage:
142     break;
143   default:
144     llvm_unreachable("Unknown linkage type!");
145   }
146 
147   EmitAlignment(Align > 2 ? Align : 2, GV);
148 
149   if (GV->isThreadLocal()) {
150     report_fatal_error("TLS is not supported by this target!");
151   }
152   unsigned Size = DL.getTypeAllocSize(C->getType());
153   if (MAI->hasDotTypeDotSizeDirective()) {
154     OutStreamer->EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
155     OutStreamer->emitELFSize(GVSym, MCConstantExpr::create(Size, OutContext));
156   }
157   OutStreamer->EmitLabel(GVSym);
158 
159   EmitGlobalConstant(DL, C);
160   // The ABI requires that unsigned scalar types smaller than 32 bits
161   // are padded to 32 bits.
162   if (Size < 4)
163     OutStreamer->EmitZeros(4 - Size);
164 
165   // Mark the end of the global
166   getTargetStreamer().emitCCBottomData(GVSym->getName());
167 }
168 
169 void XCoreAsmPrinter::EmitFunctionBodyStart() {
170   MCInstLowering.Initialize(&MF->getContext());
171 }
172 
173 /// EmitFunctionBodyEnd - Targets can override this to emit stuff after
174 /// the last basic block in the function.
175 void XCoreAsmPrinter::EmitFunctionBodyEnd() {
176   // Emit function end directives
177   getTargetStreamer().emitCCBottomFunction(CurrentFnSym->getName());
178 }
179 
180 void XCoreAsmPrinter::EmitFunctionEntryLabel() {
181   // Mark the start of the function
182   getTargetStreamer().emitCCTopFunction(CurrentFnSym->getName());
183   OutStreamer->EmitLabel(CurrentFnSym);
184 }
185 
186 void XCoreAsmPrinter::
187 printInlineJT(const MachineInstr *MI, int opNum, raw_ostream &O,
188               const std::string &directive) {
189   unsigned JTI = MI->getOperand(opNum).getIndex();
190   const MachineFunction *MF = MI->getParent()->getParent();
191   const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
192   const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
193   const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
194   O << "\t" << directive << " ";
195   for (unsigned i = 0, e = JTBBs.size(); i != e; ++i) {
196     MachineBasicBlock *MBB = JTBBs[i];
197     if (i > 0)
198       O << ",";
199     MBB->getSymbol()->print(O, MAI);
200   }
201 }
202 
203 void XCoreAsmPrinter::printOperand(const MachineInstr *MI, int opNum,
204                                    raw_ostream &O) {
205   const DataLayout &DL = getDataLayout();
206   const MachineOperand &MO = MI->getOperand(opNum);
207   switch (MO.getType()) {
208   case MachineOperand::MO_Register:
209     O << XCoreInstPrinter::getRegisterName(MO.getReg());
210     break;
211   case MachineOperand::MO_Immediate:
212     O << MO.getImm();
213     break;
214   case MachineOperand::MO_MachineBasicBlock:
215     MO.getMBB()->getSymbol()->print(O, MAI);
216     break;
217   case MachineOperand::MO_GlobalAddress:
218     getSymbol(MO.getGlobal())->print(O, MAI);
219     break;
220   case MachineOperand::MO_ConstantPoolIndex:
221     O << DL.getPrivateGlobalPrefix() << "CPI" << getFunctionNumber() << '_'
222       << MO.getIndex();
223     break;
224   case MachineOperand::MO_BlockAddress:
225     GetBlockAddressSymbol(MO.getBlockAddress())->print(O, MAI);
226     break;
227   default:
228     llvm_unreachable("not implemented");
229   }
230 }
231 
232 /// PrintAsmOperand - Print out an operand for an inline asm expression.
233 ///
234 bool XCoreAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
235                                       unsigned AsmVariant,const char *ExtraCode,
236                                       raw_ostream &O) {
237   // Print the operand if there is no operand modifier.
238   if (!ExtraCode || !ExtraCode[0]) {
239     printOperand(MI, OpNo, O);
240     return false;
241   }
242 
243   // Otherwise fallback on the default implementation.
244   return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, O);
245 }
246 
247 bool XCoreAsmPrinter::
248 PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNum,
249                       unsigned AsmVariant, const char *ExtraCode,
250                       raw_ostream &O) {
251   if (ExtraCode && ExtraCode[0]) {
252     return true; // Unknown modifier.
253   }
254   printOperand(MI, OpNum, O);
255   O << '[';
256   printOperand(MI, OpNum + 1, O);
257   O << ']';
258   return false;
259 }
260 
261 void XCoreAsmPrinter::EmitInstruction(const MachineInstr *MI) {
262   SmallString<128> Str;
263   raw_svector_ostream O(Str);
264 
265   switch (MI->getOpcode()) {
266   case XCore::DBG_VALUE:
267     llvm_unreachable("Should be handled target independently");
268   case XCore::ADD_2rus:
269     if (MI->getOperand(2).getImm() == 0) {
270       O << "\tmov "
271         << XCoreInstPrinter::getRegisterName(MI->getOperand(0).getReg()) << ", "
272         << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg());
273       OutStreamer->EmitRawText(O.str());
274       return;
275     }
276     break;
277   case XCore::BR_JT:
278   case XCore::BR_JT32:
279     O << "\tbru "
280       << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg()) << '\n';
281     if (MI->getOpcode() == XCore::BR_JT)
282       printInlineJT(MI, 0, O);
283     else
284       printInlineJT32(MI, 0, O);
285     O << '\n';
286     OutStreamer->EmitRawText(O.str());
287     return;
288   }
289 
290   MCInst TmpInst;
291   MCInstLowering.Lower(MI, TmpInst);
292 
293   EmitToStreamer(*OutStreamer, TmpInst);
294 }
295 
296 // Force static initialization.
297 extern "C" void LLVMInitializeXCoreAsmPrinter() {
298   RegisterAsmPrinter<XCoreAsmPrinter> X(getTheXCoreTarget());
299 }
300