1 //===-- XCoreAsmPrinter.cpp - XCore LLVM assembly writer ------------------===//
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 contains a printer that converts from our internal representation
11 // of machine-dependent LLVM code to the XAS-format XCore assembly language.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "XCore.h"
16 #include "InstPrinter/XCoreInstPrinter.h"
17 #include "XCoreInstrInfo.h"
18 #include "XCoreMCInstLower.h"
19 #include "XCoreSubtarget.h"
20 #include "XCoreTargetMachine.h"
21 #include "XCoreTargetStreamer.h"
22 #include "llvm/ADT/SmallString.h"
23 #include "llvm/ADT/StringExtras.h"
24 #include "llvm/CodeGen/AsmPrinter.h"
25 #include "llvm/CodeGen/MachineConstantPool.h"
26 #include "llvm/CodeGen/MachineFunctionPass.h"
27 #include "llvm/CodeGen/MachineInstr.h"
28 #include "llvm/CodeGen/MachineJumpTableInfo.h"
29 #include "llvm/CodeGen/MachineModuleInfo.h"
30 #include "llvm/IR/Constants.h"
31 #include "llvm/IR/DataLayout.h"
32 #include "llvm/IR/DebugInfo.h"
33 #include "llvm/IR/DerivedTypes.h"
34 #include "llvm/IR/Mangler.h"
35 #include "llvm/IR/Module.h"
36 #include "llvm/MC/MCAsmInfo.h"
37 #include "llvm/MC/MCExpr.h"
38 #include "llvm/MC/MCInst.h"
39 #include "llvm/MC/MCStreamer.h"
40 #include "llvm/MC/MCSymbolELF.h"
41 #include "llvm/Support/ErrorHandling.h"
42 #include "llvm/Support/TargetRegistry.h"
43 #include "llvm/Support/raw_ostream.h"
44 #include "llvm/Target/TargetLoweringObjectFile.h"
45 #include <algorithm>
46 #include <cctype>
47 using namespace llvm;
48 
49 #define DEBUG_TYPE "asm-printer"
50 
51 namespace {
52   class XCoreAsmPrinter : public AsmPrinter {
53     XCoreMCInstLower MCInstLowering;
54     XCoreTargetStreamer &getTargetStreamer();
55 
56   public:
57     explicit XCoreAsmPrinter(TargetMachine &TM,
58                              std::unique_ptr<MCStreamer> Streamer)
59         : AsmPrinter(TM, std::move(Streamer)), MCInstLowering(*this) {}
60 
61     const char *getPassName() const override {
62       return "XCore Assembly Printer";
63     }
64 
65     void printInlineJT(const MachineInstr *MI, int opNum, raw_ostream &O,
66                        const std::string &directive = ".jmptable");
67     void printInlineJT32(const MachineInstr *MI, int opNum, raw_ostream &O) {
68       printInlineJT(MI, opNum, O, ".jmptable32");
69     }
70     void printOperand(const MachineInstr *MI, int opNum, raw_ostream &O);
71     bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
72                          unsigned AsmVariant, const char *ExtraCode,
73                          raw_ostream &O) override;
74     bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNum,
75                                unsigned AsmVariant, const char *ExtraCode,
76                                raw_ostream &O) override;
77 
78     void emitArrayBound(MCSymbol *Sym, const GlobalVariable *GV);
79     void EmitGlobalVariable(const GlobalVariable *GV) override;
80 
81     void EmitFunctionEntryLabel() override;
82     void EmitInstruction(const MachineInstr *MI) override;
83     void EmitFunctionBodyStart() override;
84     void EmitFunctionBodyEnd() override;
85   };
86 } // end of anonymous namespace
87 
88 XCoreTargetStreamer &XCoreAsmPrinter::getTargetStreamer() {
89   return static_cast<XCoreTargetStreamer&>(*OutStreamer->getTargetStreamer());
90 }
91 
92 void XCoreAsmPrinter::emitArrayBound(MCSymbol *Sym, const GlobalVariable *GV) {
93   assert( ( GV->hasExternalLinkage() || GV->hasWeakLinkage() ||
94             GV->hasLinkOnceLinkage() || GV->hasCommonLinkage() ) &&
95           "Unexpected linkage");
96   if (ArrayType *ATy = dyn_cast<ArrayType>(GV->getValueType())) {
97 
98     MCSymbol *SymGlob = OutContext.getOrCreateSymbol(
99                           Twine(Sym->getName() + StringRef(".globound")));
100     OutStreamer->EmitSymbolAttribute(SymGlob, MCSA_Global);
101     OutStreamer->EmitAssignment(SymGlob,
102                                 MCConstantExpr::create(ATy->getNumElements(),
103                                                        OutContext));
104     if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
105         GV->hasCommonLinkage()) {
106       OutStreamer->EmitSymbolAttribute(SymGlob, MCSA_Weak);
107     }
108   }
109 }
110 
111 void XCoreAsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
112   // Check to see if this is a special global used by LLVM, if so, emit it.
113   if (!GV->hasInitializer() ||
114       EmitSpecialLLVMGlobal(GV))
115     return;
116 
117   const DataLayout &DL = getDataLayout();
118   OutStreamer->SwitchSection(getObjFileLowering().SectionForGlobal(GV, TM));
119 
120   MCSymbol *GVSym = getSymbol(GV);
121   const Constant *C = GV->getInitializer();
122   unsigned Align = (unsigned)DL.getPreferredTypeAlignmentShift(C->getType());
123 
124   // Mark the start of the global
125   getTargetStreamer().emitCCTopData(GVSym->getName());
126 
127   switch (GV->getLinkage()) {
128   case GlobalValue::AppendingLinkage:
129     report_fatal_error("AppendingLinkage is not supported by this target!");
130   case GlobalValue::LinkOnceAnyLinkage:
131   case GlobalValue::LinkOnceODRLinkage:
132   case GlobalValue::WeakAnyLinkage:
133   case GlobalValue::WeakODRLinkage:
134   case GlobalValue::ExternalLinkage:
135   case GlobalValue::CommonLinkage:
136     emitArrayBound(GVSym, GV);
137     OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
138 
139     if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
140         GV->hasCommonLinkage())
141       OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Weak);
142     LLVM_FALLTHROUGH;
143   case GlobalValue::InternalLinkage:
144   case GlobalValue::PrivateLinkage:
145     break;
146   default:
147     llvm_unreachable("Unknown linkage type!");
148   }
149 
150   EmitAlignment(Align > 2 ? Align : 2, GV);
151 
152   if (GV->isThreadLocal()) {
153     report_fatal_error("TLS is not supported by this target!");
154   }
155   unsigned Size = DL.getTypeAllocSize(C->getType());
156   if (MAI->hasDotTypeDotSizeDirective()) {
157     OutStreamer->EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
158     OutStreamer->emitELFSize(cast<MCSymbolELF>(GVSym),
159                              MCConstantExpr::create(Size, OutContext));
160   }
161   OutStreamer->EmitLabel(GVSym);
162 
163   EmitGlobalConstant(DL, C);
164   // The ABI requires that unsigned scalar types smaller than 32 bits
165   // are padded to 32 bits.
166   if (Size < 4)
167     OutStreamer->EmitZeros(4 - Size);
168 
169   // Mark the end of the global
170   getTargetStreamer().emitCCBottomData(GVSym->getName());
171 }
172 
173 void XCoreAsmPrinter::EmitFunctionBodyStart() {
174   MCInstLowering.Initialize(&MF->getContext());
175 }
176 
177 /// EmitFunctionBodyEnd - Targets can override this to emit stuff after
178 /// the last basic block in the function.
179 void XCoreAsmPrinter::EmitFunctionBodyEnd() {
180   // Emit function end directives
181   getTargetStreamer().emitCCBottomFunction(CurrentFnSym->getName());
182 }
183 
184 void XCoreAsmPrinter::EmitFunctionEntryLabel() {
185   // Mark the start of the function
186   getTargetStreamer().emitCCTopFunction(CurrentFnSym->getName());
187   OutStreamer->EmitLabel(CurrentFnSym);
188 }
189 
190 void XCoreAsmPrinter::
191 printInlineJT(const MachineInstr *MI, int opNum, raw_ostream &O,
192               const std::string &directive) {
193   unsigned JTI = MI->getOperand(opNum).getIndex();
194   const MachineFunction *MF = MI->getParent()->getParent();
195   const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
196   const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
197   const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
198   O << "\t" << directive << " ";
199   for (unsigned i = 0, e = JTBBs.size(); i != e; ++i) {
200     MachineBasicBlock *MBB = JTBBs[i];
201     if (i > 0)
202       O << ",";
203     MBB->getSymbol()->print(O, MAI);
204   }
205 }
206 
207 void XCoreAsmPrinter::printOperand(const MachineInstr *MI, int opNum,
208                                    raw_ostream &O) {
209   const DataLayout &DL = getDataLayout();
210   const MachineOperand &MO = MI->getOperand(opNum);
211   switch (MO.getType()) {
212   case MachineOperand::MO_Register:
213     O << XCoreInstPrinter::getRegisterName(MO.getReg());
214     break;
215   case MachineOperand::MO_Immediate:
216     O << MO.getImm();
217     break;
218   case MachineOperand::MO_MachineBasicBlock:
219     MO.getMBB()->getSymbol()->print(O, MAI);
220     break;
221   case MachineOperand::MO_GlobalAddress:
222     getSymbol(MO.getGlobal())->print(O, MAI);
223     break;
224   case MachineOperand::MO_ConstantPoolIndex:
225     O << DL.getPrivateGlobalPrefix() << "CPI" << getFunctionNumber() << '_'
226       << MO.getIndex();
227     break;
228   case MachineOperand::MO_BlockAddress:
229     GetBlockAddressSymbol(MO.getBlockAddress())->print(O, MAI);
230     break;
231   default:
232     llvm_unreachable("not implemented");
233   }
234 }
235 
236 /// PrintAsmOperand - Print out an operand for an inline asm expression.
237 ///
238 bool XCoreAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
239                                       unsigned AsmVariant,const char *ExtraCode,
240                                       raw_ostream &O) {
241   // Print the operand if there is no operand modifier.
242   if (!ExtraCode || !ExtraCode[0]) {
243     printOperand(MI, OpNo, O);
244     return false;
245   }
246 
247   // Otherwise fallback on the default implementation.
248   return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, O);
249 }
250 
251 bool XCoreAsmPrinter::
252 PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNum,
253                       unsigned AsmVariant, const char *ExtraCode,
254                       raw_ostream &O) {
255   if (ExtraCode && ExtraCode[0]) {
256     return true; // Unknown modifier.
257   }
258   printOperand(MI, OpNum, O);
259   O << '[';
260   printOperand(MI, OpNum + 1, O);
261   O << ']';
262   return false;
263 }
264 
265 void XCoreAsmPrinter::EmitInstruction(const MachineInstr *MI) {
266   SmallString<128> Str;
267   raw_svector_ostream O(Str);
268 
269   switch (MI->getOpcode()) {
270   case XCore::DBG_VALUE:
271     llvm_unreachable("Should be handled target independently");
272   case XCore::ADD_2rus:
273     if (MI->getOperand(2).getImm() == 0) {
274       O << "\tmov "
275         << XCoreInstPrinter::getRegisterName(MI->getOperand(0).getReg()) << ", "
276         << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg());
277       OutStreamer->EmitRawText(O.str());
278       return;
279     }
280     break;
281   case XCore::BR_JT:
282   case XCore::BR_JT32:
283     O << "\tbru "
284       << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg()) << '\n';
285     if (MI->getOpcode() == XCore::BR_JT)
286       printInlineJT(MI, 0, O);
287     else
288       printInlineJT32(MI, 0, O);
289     O << '\n';
290     OutStreamer->EmitRawText(O.str());
291     return;
292   }
293 
294   MCInst TmpInst;
295   MCInstLowering.Lower(MI, TmpInst);
296 
297   EmitToStreamer(*OutStreamer, TmpInst);
298 }
299 
300 // Force static initialization.
301 extern "C" void LLVMInitializeXCoreAsmPrinter() {
302   RegisterAsmPrinter<XCoreAsmPrinter> X(TheXCoreTarget);
303 }
304