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 "XCoreTargetStreamer.h"
18 #include "InstPrinter/XCoreInstPrinter.h"
19 #include "XCoreInstrInfo.h"
20 #include "XCoreMCInstLower.h"
21 #include "XCoreSubtarget.h"
22 #include "XCoreTargetMachine.h"
23 #include "llvm/ADT/SmallString.h"
24 #include "llvm/ADT/StringExtras.h"
25 #include "llvm/CodeGen/AsmPrinter.h"
26 #include "llvm/CodeGen/MachineConstantPool.h"
27 #include "llvm/CodeGen/MachineFunctionPass.h"
28 #include "llvm/CodeGen/MachineInstr.h"
29 #include "llvm/CodeGen/MachineJumpTableInfo.h"
30 #include "llvm/CodeGen/MachineModuleInfo.h"
31 #include "llvm/DebugInfo.h"
32 #include "llvm/IR/Constants.h"
33 #include "llvm/IR/DataLayout.h"
34 #include "llvm/IR/DerivedTypes.h"
35 #include "llvm/IR/Mangler.h"
36 #include "llvm/IR/Module.h"
37 #include "llvm/MC/MCAsmInfo.h"
38 #include "llvm/MC/MCExpr.h"
39 #include "llvm/MC/MCInst.h"
40 #include "llvm/MC/MCStreamer.h"
41 #include "llvm/MC/MCSymbol.h"
42 #include "llvm/Support/ErrorHandling.h"
43 #include "llvm/Support/TargetRegistry.h"
44 #include "llvm/Support/raw_ostream.h"
45 #include "llvm/Target/TargetLoweringObjectFile.h"
46 #include <algorithm>
47 #include <cctype>
48 using namespace llvm;
49 
50 namespace {
51   class XCoreAsmPrinter : public AsmPrinter {
52     const XCoreSubtarget &Subtarget;
53     XCoreMCInstLower MCInstLowering;
54     XCoreTargetStreamer &getTargetStreamer();
55 
56   public:
57     explicit XCoreAsmPrinter(TargetMachine &TM, MCStreamer &Streamer)
58       : AsmPrinter(TM, Streamer), Subtarget(TM.getSubtarget<XCoreSubtarget>()),
59         MCInstLowering(*this) {}
60 
61     virtual const char *getPassName() const {
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);
74 
75     void emitArrayBound(MCSymbol *Sym, const GlobalVariable *GV);
76     virtual void EmitGlobalVariable(const GlobalVariable *GV);
77 
78     void EmitFunctionEntryLabel();
79     void EmitInstruction(const MachineInstr *MI);
80     void EmitFunctionBodyStart();
81     void EmitFunctionBodyEnd();
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>(
94                         cast<PointerType>(GV->getType())->getElementType())) {
95 
96     MCSymbol *SymGlob = OutContext.GetOrCreateSymbol(
97                           Twine(Sym->getName() + StringRef(".globound")));
98     OutStreamer.EmitSymbolAttribute(SymGlob, MCSA_Global);
99     OutStreamer.EmitAssignment(SymGlob,
100                                MCConstantExpr::Create(ATy->getNumElements(),
101                                                       OutContext));
102     if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
103         GV->hasCommonLinkage()) {
104       // TODO Use COMDAT groups for LinkOnceLinkage
105       OutStreamer.EmitSymbolAttribute(SymGlob, MCSA_Weak);
106     }
107   }
108 }
109 
110 void XCoreAsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
111   // Check to see if this is a special global used by LLVM, if so, emit it.
112   if (!GV->hasInitializer() ||
113       EmitSpecialLLVMGlobal(GV))
114     return;
115 
116   const DataLayout *TD = TM.getDataLayout();
117   OutStreamer.SwitchSection(
118       getObjFileLowering().SectionForGlobal(GV, *Mang, TM));
119 
120   MCSymbol *GVSym = getSymbol(GV);
121   const Constant *C = GV->getInitializer();
122   unsigned Align = (unsigned)TD->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     // TODO Use COMDAT groups for LinkOnceLinkage
140     if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
141         GV->hasCommonLinkage())
142       OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak);
143     // FALL THROUGH
144   case GlobalValue::InternalLinkage:
145   case GlobalValue::PrivateLinkage:
146     break;
147   default:
148     llvm_unreachable("Unknown linkage type!");
149   }
150 
151   EmitAlignment(Align > 2 ? Align : 2, GV);
152 
153   if (GV->isThreadLocal()) {
154     report_fatal_error("TLS is not supported by this target!");
155   }
156   unsigned Size = TD->getTypeAllocSize(C->getType());
157   if (MAI->hasDotTypeDotSizeDirective()) {
158     OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
159     OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext));
160   }
161   OutStreamer.EmitLabel(GVSym);
162 
163   EmitGlobalConstant(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(Mang, &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     O << *MBB->getSymbol();
204   }
205 }
206 
207 void XCoreAsmPrinter::printOperand(const MachineInstr *MI, int opNum,
208                                    raw_ostream &O) {
209   const DataLayout *DL = TM.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     O << *MO.getMBB()->getSymbol();
220     break;
221   case MachineOperand::MO_GlobalAddress:
222     O << *getSymbol(MO.getGlobal());
223     break;
224   case MachineOperand::MO_ConstantPoolIndex:
225     O << DL->getPrivateGlobalPrefix() << "CPI" << getFunctionNumber()
226       << '_' << MO.getIndex();
227     break;
228   case MachineOperand::MO_BlockAddress:
229     O << *GetBlockAddressSymbol(MO.getBlockAddress());
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 void XCoreAsmPrinter::EmitInstruction(const MachineInstr *MI) {
252   SmallString<128> Str;
253   raw_svector_ostream O(Str);
254 
255   switch (MI->getOpcode()) {
256   case XCore::DBG_VALUE:
257     llvm_unreachable("Should be handled target independently");
258   case XCore::ADD_2rus:
259     if (MI->getOperand(2).getImm() == 0) {
260       O << "\tmov "
261         << XCoreInstPrinter::getRegisterName(MI->getOperand(0).getReg()) << ", "
262         << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg());
263       OutStreamer.EmitRawText(O.str());
264       return;
265     }
266     break;
267   case XCore::BR_JT:
268   case XCore::BR_JT32:
269     O << "\tbru "
270       << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg()) << '\n';
271     if (MI->getOpcode() == XCore::BR_JT)
272       printInlineJT(MI, 0, O);
273     else
274       printInlineJT32(MI, 0, O);
275     O << '\n';
276     OutStreamer.EmitRawText(O.str());
277     return;
278   }
279 
280   MCInst TmpInst;
281   MCInstLowering.Lower(MI, TmpInst);
282 
283   EmitToStreamer(OutStreamer, TmpInst);
284 }
285 
286 // Force static initialization.
287 extern "C" void LLVMInitializeXCoreAsmPrinter() {
288   RegisterAsmPrinter<XCoreAsmPrinter> X(TheXCoreTarget);
289 }
290