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 #define DEBUG_TYPE "asm-printer"
16 #include "XCore.h"
17 #include "InstPrinter/XCoreInstPrinter.h"
18 #include "XCoreInstrInfo.h"
19 #include "XCoreMCInstLower.h"
20 #include "XCoreSubtarget.h"
21 #include "XCoreTargetMachine.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/DebugInfo.h"
31 #include "llvm/IR/Constants.h"
32 #include "llvm/IR/DataLayout.h"
33 #include "llvm/IR/DerivedTypes.h"
34 #include "llvm/IR/Module.h"
35 #include "llvm/MC/MCAsmInfo.h"
36 #include "llvm/MC/MCInst.h"
37 #include "llvm/MC/MCStreamer.h"
38 #include "llvm/MC/MCSymbol.h"
39 #include "llvm/Support/ErrorHandling.h"
40 #include "llvm/Support/TargetRegistry.h"
41 #include "llvm/Support/raw_ostream.h"
42 #include "llvm/Target/Mangler.h"
43 #include "llvm/Target/TargetLoweringObjectFile.h"
44 #include <algorithm>
45 #include <cctype>
46 using namespace llvm;
47 
48 namespace {
49   class XCoreAsmPrinter : public AsmPrinter {
50     const XCoreSubtarget &Subtarget;
51     XCoreMCInstLower MCInstLowering;
52     void PrintDebugValueComment(const MachineInstr *MI, raw_ostream &OS);
53   public:
54     explicit XCoreAsmPrinter(TargetMachine &TM, MCStreamer &Streamer)
55       : AsmPrinter(TM, Streamer), Subtarget(TM.getSubtarget<XCoreSubtarget>()),
56         MCInstLowering(*this) {}
57 
58     virtual const char *getPassName() const {
59       return "XCore Assembly Printer";
60     }
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);
71 
72     void emitArrayBound(MCSymbol *Sym, const GlobalVariable *GV);
73     virtual void EmitGlobalVariable(const GlobalVariable *GV);
74 
75     void EmitFunctionEntryLabel();
76     void EmitInstruction(const MachineInstr *MI);
77     void EmitFunctionBodyStart();
78     void EmitFunctionBodyEnd();
79     virtual MachineLocation getDebugValueLocation(const MachineInstr *MI) const;
80   };
81 } // end of anonymous namespace
82 
83 void XCoreAsmPrinter::emitArrayBound(MCSymbol *Sym, const GlobalVariable *GV) {
84   assert(((GV->hasExternalLinkage() ||
85     GV->hasWeakLinkage()) ||
86     GV->hasLinkOnceLinkage()) && "Unexpected linkage");
87   if (ArrayType *ATy = dyn_cast<ArrayType>(
88     cast<PointerType>(GV->getType())->getElementType())) {
89     OutStreamer.EmitSymbolAttribute(Sym, MCSA_Global);
90     // FIXME: MCStreamerize.
91     OutStreamer.EmitRawText(StringRef(".globound"));
92     OutStreamer.EmitRawText("\t.set\t" + Twine(Sym->getName()));
93     OutStreamer.EmitRawText(".globound," + Twine(ATy->getNumElements()));
94     if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage()) {
95       // TODO Use COMDAT groups for LinkOnceLinkage
96       OutStreamer.EmitRawText(MAI->getWeakDefDirective() +Twine(Sym->getName())+
97                               ".globound");
98     }
99   }
100 }
101 
102 void XCoreAsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
103   // Check to see if this is a special global used by LLVM, if so, emit it.
104   if (!GV->hasInitializer() ||
105       EmitSpecialLLVMGlobal(GV))
106     return;
107 
108   const DataLayout *TD = TM.getDataLayout();
109   OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(GV, Mang,TM));
110 
111 
112   MCSymbol *GVSym = Mang->getSymbol(GV);
113   const Constant *C = GV->getInitializer();
114   unsigned Align = (unsigned)TD->getPreferredTypeAlignmentShift(C->getType());
115 
116   // Mark the start of the global
117   OutStreamer.EmitRawText("\t.cc_top " + Twine(GVSym->getName()) + ".data," +
118                           GVSym->getName());
119 
120   switch (GV->getLinkage()) {
121   case GlobalValue::AppendingLinkage:
122     report_fatal_error("AppendingLinkage is not supported by this target!");
123   case GlobalValue::LinkOnceAnyLinkage:
124   case GlobalValue::LinkOnceODRLinkage:
125   case GlobalValue::WeakAnyLinkage:
126   case GlobalValue::WeakODRLinkage:
127   case GlobalValue::ExternalLinkage:
128     emitArrayBound(GVSym, GV);
129     OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
130 
131     // TODO Use COMDAT groups for LinkOnceLinkage
132     if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage())
133       OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak);
134     // FALL THROUGH
135   case GlobalValue::InternalLinkage:
136   case GlobalValue::PrivateLinkage:
137     break;
138   case GlobalValue::DLLImportLinkage:
139     llvm_unreachable("DLLImport linkage is not supported by this target!");
140   case GlobalValue::DLLExportLinkage:
141     llvm_unreachable("DLLExport linkage is not supported by this target!");
142   default:
143     llvm_unreachable("Unknown linkage type!");
144   }
145 
146   EmitAlignment(Align > 2 ? Align : 2, GV);
147 
148   if (GV->isThreadLocal()) {
149     report_fatal_error("TLS is not supported by this target!");
150   }
151   unsigned Size = TD->getTypeAllocSize(C->getType());
152   if (MAI->hasDotTypeDotSizeDirective()) {
153     OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
154     OutStreamer.EmitRawText("\t.size " + Twine(GVSym->getName()) + "," +
155                             Twine(Size));
156   }
157   OutStreamer.EmitLabel(GVSym);
158 
159   EmitGlobalConstant(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   OutStreamer.EmitRawText("\t.cc_bottom " + Twine(GVSym->getName()) + ".data");
167 }
168 
169 void XCoreAsmPrinter::EmitFunctionBodyStart() {
170   MCInstLowering.Initialize(Mang, &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   OutStreamer.EmitRawText("\t.cc_bottom " + Twine(CurrentFnSym->getName()) +
178                           ".function");
179 }
180 
181 void XCoreAsmPrinter::EmitFunctionEntryLabel() {
182   // Mark the start of the function
183   OutStreamer.EmitRawText("\t.cc_top " + Twine(CurrentFnSym->getName()) +
184                           ".function," + CurrentFnSym->getName());
185   OutStreamer.EmitLabel(CurrentFnSym);
186 }
187 
188 void XCoreAsmPrinter::
189 printInlineJT(const MachineInstr *MI, int opNum, raw_ostream &O,
190               const std::string &directive) {
191   unsigned JTI = MI->getOperand(opNum).getIndex();
192   const MachineFunction *MF = MI->getParent()->getParent();
193   const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
194   const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
195   const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
196   O << "\t" << directive << " ";
197   for (unsigned i = 0, e = JTBBs.size(); i != e; ++i) {
198     MachineBasicBlock *MBB = JTBBs[i];
199     if (i > 0)
200       O << ",";
201     O << *MBB->getSymbol();
202   }
203 }
204 
205 void XCoreAsmPrinter::printOperand(const MachineInstr *MI, int opNum,
206                                    raw_ostream &O) {
207   const MachineOperand &MO = MI->getOperand(opNum);
208   switch (MO.getType()) {
209   case MachineOperand::MO_Register:
210     O << XCoreInstPrinter::getRegisterName(MO.getReg());
211     break;
212   case MachineOperand::MO_Immediate:
213     O << MO.getImm();
214     break;
215   case MachineOperand::MO_MachineBasicBlock:
216     O << *MO.getMBB()->getSymbol();
217     break;
218   case MachineOperand::MO_GlobalAddress:
219     O << *Mang->getSymbol(MO.getGlobal());
220     break;
221   case MachineOperand::MO_ExternalSymbol:
222     O << MO.getSymbolName();
223     break;
224   case MachineOperand::MO_ConstantPoolIndex:
225     O << MAI->getPrivateGlobalPrefix() << "CPI" << getFunctionNumber()
226       << '_' << MO.getIndex();
227     break;
228   case MachineOperand::MO_JumpTableIndex:
229     O << MAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber()
230       << '_' << MO.getIndex();
231     break;
232   case MachineOperand::MO_BlockAddress:
233     O << *GetBlockAddressSymbol(MO.getBlockAddress());
234     break;
235   default:
236     llvm_unreachable("not implemented");
237   }
238 }
239 
240 /// PrintAsmOperand - Print out an operand for an inline asm expression.
241 ///
242 bool XCoreAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
243                                       unsigned AsmVariant,const char *ExtraCode,
244                                       raw_ostream &O) {
245   // Does this asm operand have a single letter operand modifier?
246   if (ExtraCode && ExtraCode[0])
247     if (ExtraCode[1] != 0) return true; // Unknown modifier.
248 
249     switch (ExtraCode[0]) {
250     default:
251       // See if this is a generic print operand
252       return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, O);
253     }
254 
255   printOperand(MI, OpNo, O);
256   return false;
257 }
258 
259 void XCoreAsmPrinter::PrintDebugValueComment(const MachineInstr *MI,
260                                              raw_ostream &OS) {
261   unsigned NOps = MI->getNumOperands();
262   assert(NOps == 4);
263   OS << '\t' << MAI->getCommentString() << "DEBUG_VALUE: ";
264   // cast away const; DIetc do not take const operands for some reason.
265   DIVariable V(const_cast<MDNode *>(MI->getOperand(NOps-1).getMetadata()));
266   OS << V.getName();
267   OS << " <- ";
268   // Frame address.  Currently handles register +- offset only.
269   assert(MI->getOperand(0).isReg() && MI->getOperand(1).isImm());
270   OS << '['; printOperand(MI, 0, OS); OS << '+'; printOperand(MI, 1, OS);
271   OS << ']';
272   OS << "+";
273   printOperand(MI, NOps-2, OS);
274 }
275 
276 MachineLocation XCoreAsmPrinter::
277 getDebugValueLocation(const MachineInstr *MI) const {
278   // Handles frame addresses emitted in XCoreInstrInfo::emitFrameIndexDebugValue.
279   assert(MI->getNumOperands() == 4 && "Invalid no. of machine operands!");
280   assert(MI->getOperand(0).isReg() && MI->getOperand(1).isImm() &&
281          "Unexpected MachineOperand types");
282   return MachineLocation(MI->getOperand(0).getReg(),
283                          MI->getOperand(1).getImm());
284 }
285 
286 void XCoreAsmPrinter::EmitInstruction(const MachineInstr *MI) {
287   SmallString<128> Str;
288   raw_svector_ostream O(Str);
289 
290   switch (MI->getOpcode()) {
291   case XCore::DBG_VALUE: {
292     if (isVerbose() && OutStreamer.hasRawTextSupport()) {
293       SmallString<128> TmpStr;
294       raw_svector_ostream OS(TmpStr);
295       PrintDebugValueComment(MI, OS);
296       OutStreamer.EmitRawText(StringRef(OS.str()));
297     }
298     return;
299   }
300   case XCore::ADD_2rus:
301     if (MI->getOperand(2).getImm() == 0) {
302       O << "\tmov "
303         << XCoreInstPrinter::getRegisterName(MI->getOperand(0).getReg()) << ", "
304         << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg());
305       OutStreamer.EmitRawText(O.str());
306       return;
307     }
308     break;
309   case XCore::BR_JT:
310   case XCore::BR_JT32:
311     O << "\tbru "
312       << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg()) << '\n';
313     if (MI->getOpcode() == XCore::BR_JT)
314       printInlineJT(MI, 0, O);
315     else
316       printInlineJT32(MI, 0, O);
317     O << '\n';
318     OutStreamer.EmitRawText(O.str());
319     return;
320   }
321 
322   MCInst TmpInst;
323   MCInstLowering.Lower(MI, TmpInst);
324 
325   OutStreamer.EmitInstruction(TmpInst);
326 }
327 
328 // Force static initialization.
329 extern "C" void LLVMInitializeXCoreAsmPrinter() {
330   RegisterAsmPrinter<XCoreAsmPrinter> X(TheXCoreTarget);
331 }
332