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() ||
91     GV->hasWeakLinkage()) ||
92     GV->hasLinkOnceLinkage()) && "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       // TODO Use COMDAT groups for LinkOnceLinkage
104       OutStreamer.EmitSymbolAttribute(SymGlob, MCSA_Weak);
105     }
106   }
107 }
108 
109 void XCoreAsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
110   // Check to see if this is a special global used by LLVM, if so, emit it.
111   if (!GV->hasInitializer() ||
112       EmitSpecialLLVMGlobal(GV))
113     return;
114 
115   const DataLayout *TD = TM.getDataLayout();
116   OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(GV, Mang,TM));
117 
118 
119   MCSymbol *GVSym = getSymbol(GV);
120   const Constant *C = GV->getInitializer();
121   unsigned Align = (unsigned)TD->getPreferredTypeAlignmentShift(C->getType());
122 
123   // Mark the start of the global
124   getTargetStreamer().emitCCTopData(GVSym->getName());
125 
126   switch (GV->getLinkage()) {
127   case GlobalValue::AppendingLinkage:
128     report_fatal_error("AppendingLinkage is not supported by this target!");
129   case GlobalValue::LinkOnceAnyLinkage:
130   case GlobalValue::LinkOnceODRLinkage:
131   case GlobalValue::WeakAnyLinkage:
132   case GlobalValue::WeakODRLinkage:
133   case GlobalValue::ExternalLinkage:
134     emitArrayBound(GVSym, GV);
135     OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
136 
137     // TODO Use COMDAT groups for LinkOnceLinkage
138     if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage())
139       OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak);
140     // FALL THROUGH
141   case GlobalValue::InternalLinkage:
142   case GlobalValue::PrivateLinkage:
143     break;
144   default:
145     llvm_unreachable("Unknown linkage type!");
146   }
147 
148   EmitAlignment(Align > 2 ? Align : 2, GV);
149 
150   if (GV->isThreadLocal()) {
151     report_fatal_error("TLS is not supported by this target!");
152   }
153   unsigned Size = TD->getTypeAllocSize(C->getType());
154   if (MAI->hasDotTypeDotSizeDirective()) {
155     OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
156     OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext));
157   }
158   OutStreamer.EmitLabel(GVSym);
159 
160   EmitGlobalConstant(C);
161   // The ABI requires that unsigned scalar types smaller than 32 bits
162   // are padded to 32 bits.
163   if (Size < 4)
164     OutStreamer.EmitZeros(4 - Size);
165 
166   // Mark the end of the global
167   getTargetStreamer().emitCCBottomData(GVSym->getName());
168 }
169 
170 void XCoreAsmPrinter::EmitFunctionBodyStart() {
171   MCInstLowering.Initialize(Mang, &MF->getContext());
172 }
173 
174 /// EmitFunctionBodyEnd - Targets can override this to emit stuff after
175 /// the last basic block in the function.
176 void XCoreAsmPrinter::EmitFunctionBodyEnd() {
177   // Emit function end directives
178   getTargetStreamer().emitCCBottomFunction(CurrentFnSym->getName());
179 }
180 
181 void XCoreAsmPrinter::EmitFunctionEntryLabel() {
182   // Mark the start of the function
183   getTargetStreamer().emitCCTopFunction(CurrentFnSym->getName());
184   OutStreamer.EmitLabel(CurrentFnSym);
185 }
186 
187 void XCoreAsmPrinter::
188 printInlineJT(const MachineInstr *MI, int opNum, raw_ostream &O,
189               const std::string &directive) {
190   unsigned JTI = MI->getOperand(opNum).getIndex();
191   const MachineFunction *MF = MI->getParent()->getParent();
192   const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
193   const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
194   const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
195   O << "\t" << directive << " ";
196   for (unsigned i = 0, e = JTBBs.size(); i != e; ++i) {
197     MachineBasicBlock *MBB = JTBBs[i];
198     if (i > 0)
199       O << ",";
200     O << *MBB->getSymbol();
201   }
202 }
203 
204 void XCoreAsmPrinter::printOperand(const MachineInstr *MI, int opNum,
205                                    raw_ostream &O) {
206   const DataLayout *DL = TM.getDataLayout();
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 << *getSymbol(MO.getGlobal());
220     break;
221   case MachineOperand::MO_ConstantPoolIndex:
222     O << DL->getPrivateGlobalPrefix() << "CPI" << getFunctionNumber()
223       << '_' << MO.getIndex();
224     break;
225   case MachineOperand::MO_BlockAddress:
226     O << *GetBlockAddressSymbol(MO.getBlockAddress());
227     break;
228   default:
229     llvm_unreachable("not implemented");
230   }
231 }
232 
233 /// PrintAsmOperand - Print out an operand for an inline asm expression.
234 ///
235 bool XCoreAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
236                                       unsigned AsmVariant,const char *ExtraCode,
237                                       raw_ostream &O) {
238   // Print the operand if there is no operand modifier.
239   if (!ExtraCode || !ExtraCode[0]) {
240     printOperand(MI, OpNo, O);
241     return false;
242   }
243 
244   // Otherwise fallback on the default implementation.
245   return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, O);
246 }
247 
248 void XCoreAsmPrinter::EmitInstruction(const MachineInstr *MI) {
249   SmallString<128> Str;
250   raw_svector_ostream O(Str);
251 
252   switch (MI->getOpcode()) {
253   case XCore::DBG_VALUE:
254     llvm_unreachable("Should be handled target independently");
255   case XCore::ADD_2rus:
256     if (MI->getOperand(2).getImm() == 0) {
257       O << "\tmov "
258         << XCoreInstPrinter::getRegisterName(MI->getOperand(0).getReg()) << ", "
259         << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg());
260       OutStreamer.EmitRawText(O.str());
261       return;
262     }
263     break;
264   case XCore::BR_JT:
265   case XCore::BR_JT32:
266     O << "\tbru "
267       << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg()) << '\n';
268     if (MI->getOpcode() == XCore::BR_JT)
269       printInlineJT(MI, 0, O);
270     else
271       printInlineJT32(MI, 0, O);
272     O << '\n';
273     OutStreamer.EmitRawText(O.str());
274     return;
275   }
276 
277   MCInst TmpInst;
278   MCInstLowering.Lower(MI, TmpInst);
279 
280   EmitToStreamer(OutStreamer, TmpInst);
281 }
282 
283 // Force static initialization.
284 extern "C" void LLVMInitializeXCoreAsmPrinter() {
285   RegisterAsmPrinter<XCoreAsmPrinter> X(TheXCoreTarget);
286 }
287