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   public:
53     explicit XCoreAsmPrinter(TargetMachine &TM, MCStreamer &Streamer)
54       : AsmPrinter(TM, Streamer), Subtarget(TM.getSubtarget<XCoreSubtarget>()),
55         MCInstLowering(*this) {}
56 
57     virtual const char *getPassName() const {
58       return "XCore Assembly Printer";
59     }
60 
61     void printInlineJT(const MachineInstr *MI, int opNum, raw_ostream &O,
62                        const std::string &directive = ".jmptable");
63     void printInlineJT32(const MachineInstr *MI, int opNum, raw_ostream &O) {
64       printInlineJT(MI, opNum, O, ".jmptable32");
65     }
66     void printOperand(const MachineInstr *MI, int opNum, raw_ostream &O);
67     bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
68                          unsigned AsmVariant, const char *ExtraCode,
69                          raw_ostream &O);
70 
71     void emitArrayBound(MCSymbol *Sym, const GlobalVariable *GV);
72     virtual void EmitGlobalVariable(const GlobalVariable *GV);
73 
74     void EmitFunctionEntryLabel();
75     void EmitInstruction(const MachineInstr *MI);
76     void EmitFunctionBodyStart();
77     void EmitFunctionBodyEnd();
78   };
79 } // end of anonymous namespace
80 
81 void XCoreAsmPrinter::emitArrayBound(MCSymbol *Sym, const GlobalVariable *GV) {
82   assert(((GV->hasExternalLinkage() ||
83     GV->hasWeakLinkage()) ||
84     GV->hasLinkOnceLinkage()) && "Unexpected linkage");
85   if (ArrayType *ATy = dyn_cast<ArrayType>(
86     cast<PointerType>(GV->getType())->getElementType())) {
87     OutStreamer.EmitSymbolAttribute(Sym, MCSA_Global);
88     // FIXME: MCStreamerize.
89     OutStreamer.EmitRawText(StringRef(".globound"));
90     OutStreamer.EmitRawText("\t.set\t" + Twine(Sym->getName()));
91     OutStreamer.EmitRawText(".globound," + Twine(ATy->getNumElements()));
92     if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage()) {
93       // TODO Use COMDAT groups for LinkOnceLinkage
94       OutStreamer.EmitRawText(MAI->getWeakDefDirective() +Twine(Sym->getName())+
95                               ".globound");
96     }
97   }
98 }
99 
100 void XCoreAsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
101   // Check to see if this is a special global used by LLVM, if so, emit it.
102   if (!GV->hasInitializer() ||
103       EmitSpecialLLVMGlobal(GV))
104     return;
105 
106   const DataLayout *TD = TM.getDataLayout();
107   OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(GV, Mang,TM));
108 
109 
110   MCSymbol *GVSym = Mang->getSymbol(GV);
111   const Constant *C = GV->getInitializer();
112   unsigned Align = (unsigned)TD->getPreferredTypeAlignmentShift(C->getType());
113 
114   // Mark the start of the global
115   OutStreamer.EmitRawText("\t.cc_top " + Twine(GVSym->getName()) + ".data," +
116                           GVSym->getName());
117 
118   switch (GV->getLinkage()) {
119   case GlobalValue::AppendingLinkage:
120     report_fatal_error("AppendingLinkage is not supported by this target!");
121   case GlobalValue::LinkOnceAnyLinkage:
122   case GlobalValue::LinkOnceODRLinkage:
123   case GlobalValue::WeakAnyLinkage:
124   case GlobalValue::WeakODRLinkage:
125   case GlobalValue::ExternalLinkage:
126     emitArrayBound(GVSym, GV);
127     OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
128 
129     // TODO Use COMDAT groups for LinkOnceLinkage
130     if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage())
131       OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak);
132     // FALL THROUGH
133   case GlobalValue::InternalLinkage:
134   case GlobalValue::PrivateLinkage:
135     break;
136   case GlobalValue::DLLImportLinkage:
137     llvm_unreachable("DLLImport linkage is not supported by this target!");
138   case GlobalValue::DLLExportLinkage:
139     llvm_unreachable("DLLExport linkage is not supported by this target!");
140   default:
141     llvm_unreachable("Unknown linkage type!");
142   }
143 
144   EmitAlignment(Align > 2 ? Align : 2, GV);
145 
146   if (GV->isThreadLocal()) {
147     report_fatal_error("TLS is not supported by this target!");
148   }
149   unsigned Size = TD->getTypeAllocSize(C->getType());
150   if (MAI->hasDotTypeDotSizeDirective()) {
151     OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
152     OutStreamer.EmitRawText("\t.size " + Twine(GVSym->getName()) + "," +
153                             Twine(Size));
154   }
155   OutStreamer.EmitLabel(GVSym);
156 
157   EmitGlobalConstant(C);
158   // The ABI requires that unsigned scalar types smaller than 32 bits
159   // are padded to 32 bits.
160   if (Size < 4)
161     OutStreamer.EmitZeros(4 - Size);
162 
163   // Mark the end of the global
164   OutStreamer.EmitRawText("\t.cc_bottom " + Twine(GVSym->getName()) + ".data");
165 }
166 
167 void XCoreAsmPrinter::EmitFunctionBodyStart() {
168   MCInstLowering.Initialize(Mang, &MF->getContext());
169 }
170 
171 /// EmitFunctionBodyEnd - Targets can override this to emit stuff after
172 /// the last basic block in the function.
173 void XCoreAsmPrinter::EmitFunctionBodyEnd() {
174   // Emit function end directives
175   OutStreamer.EmitRawText("\t.cc_bottom " + Twine(CurrentFnSym->getName()) +
176                           ".function");
177 }
178 
179 void XCoreAsmPrinter::EmitFunctionEntryLabel() {
180   // Mark the start of the function
181   OutStreamer.EmitRawText("\t.cc_top " + Twine(CurrentFnSym->getName()) +
182                           ".function," + 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     O << *MBB->getSymbol();
200   }
201 }
202 
203 void XCoreAsmPrinter::printOperand(const MachineInstr *MI, int opNum,
204                                    raw_ostream &O) {
205   const MachineOperand &MO = MI->getOperand(opNum);
206   switch (MO.getType()) {
207   case MachineOperand::MO_Register:
208     O << XCoreInstPrinter::getRegisterName(MO.getReg());
209     break;
210   case MachineOperand::MO_Immediate:
211     O << MO.getImm();
212     break;
213   case MachineOperand::MO_MachineBasicBlock:
214     O << *MO.getMBB()->getSymbol();
215     break;
216   case MachineOperand::MO_GlobalAddress:
217     O << *Mang->getSymbol(MO.getGlobal());
218     break;
219   case MachineOperand::MO_ExternalSymbol:
220     O << MO.getSymbolName();
221     break;
222   case MachineOperand::MO_ConstantPoolIndex:
223     O << MAI->getPrivateGlobalPrefix() << "CPI" << getFunctionNumber()
224       << '_' << MO.getIndex();
225     break;
226   case MachineOperand::MO_JumpTableIndex:
227     O << MAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber()
228       << '_' << MO.getIndex();
229     break;
230   case MachineOperand::MO_BlockAddress:
231     O << *GetBlockAddressSymbol(MO.getBlockAddress());
232     break;
233   default:
234     llvm_unreachable("not implemented");
235   }
236 }
237 
238 /// PrintAsmOperand - Print out an operand for an inline asm expression.
239 ///
240 bool XCoreAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
241                                       unsigned AsmVariant,const char *ExtraCode,
242                                       raw_ostream &O) {
243   // Print the operand if there is no operand modifier.
244   if (!ExtraCode || !ExtraCode[0]) {
245     printOperand(MI, OpNo, O);
246     return false;
247   }
248 
249   // Otherwise fallback on the default implementation.
250   return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, O);
251 }
252 
253 void XCoreAsmPrinter::EmitInstruction(const MachineInstr *MI) {
254   SmallString<128> Str;
255   raw_svector_ostream O(Str);
256 
257   switch (MI->getOpcode()) {
258   case XCore::DBG_VALUE:
259     llvm_unreachable("Should be handled target independently");
260   case XCore::ADD_2rus:
261     if (MI->getOperand(2).getImm() == 0) {
262       O << "\tmov "
263         << XCoreInstPrinter::getRegisterName(MI->getOperand(0).getReg()) << ", "
264         << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg());
265       OutStreamer.EmitRawText(O.str());
266       return;
267     }
268     break;
269   case XCore::BR_JT:
270   case XCore::BR_JT32:
271     O << "\tbru "
272       << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg()) << '\n';
273     if (MI->getOpcode() == XCore::BR_JT)
274       printInlineJT(MI, 0, O);
275     else
276       printInlineJT32(MI, 0, O);
277     O << '\n';
278     OutStreamer.EmitRawText(O.str());
279     return;
280   }
281 
282   MCInst TmpInst;
283   MCInstLowering.Lower(MI, TmpInst);
284 
285   OutStreamer.EmitInstruction(TmpInst);
286 }
287 
288 // Force static initialization.
289 extern "C" void LLVMInitializeXCoreAsmPrinter() {
290   RegisterAsmPrinter<XCoreAsmPrinter> X(TheXCoreTarget);
291 }
292