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     StringRef getPassName() const override { return "XCore Assembly Printer"; }
62 
63     void printInlineJT(const MachineInstr *MI, int opNum, raw_ostream &O,
64                        const std::string &directive = ".jmptable");
65     void printInlineJT32(const MachineInstr *MI, int opNum, raw_ostream &O) {
66       printInlineJT(MI, opNum, O, ".jmptable32");
67     }
68     void printOperand(const MachineInstr *MI, int opNum, raw_ostream &O);
69     bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
70                          unsigned AsmVariant, const char *ExtraCode,
71                          raw_ostream &O) override;
72     bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNum,
73                                unsigned AsmVariant, const char *ExtraCode,
74                                raw_ostream &O) override;
75 
76     void emitArrayBound(MCSymbol *Sym, const GlobalVariable *GV);
77     void EmitGlobalVariable(const GlobalVariable *GV) override;
78 
79     void EmitFunctionEntryLabel() override;
80     void EmitInstruction(const MachineInstr *MI) override;
81     void EmitFunctionBodyStart() override;
82     void EmitFunctionBodyEnd() override;
83   };
84 } // end of anonymous namespace
85 
86 XCoreTargetStreamer &XCoreAsmPrinter::getTargetStreamer() {
87   return static_cast<XCoreTargetStreamer&>(*OutStreamer->getTargetStreamer());
88 }
89 
90 void XCoreAsmPrinter::emitArrayBound(MCSymbol *Sym, const GlobalVariable *GV) {
91   assert( ( GV->hasExternalLinkage() || GV->hasWeakLinkage() ||
92             GV->hasLinkOnceLinkage() || GV->hasCommonLinkage() ) &&
93           "Unexpected linkage");
94   if (ArrayType *ATy = dyn_cast<ArrayType>(GV->getValueType())) {
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       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 &DL = getDataLayout();
116   OutStreamer->SwitchSection(getObjFileLowering().SectionForGlobal(GV, TM));
117 
118   MCSymbol *GVSym = getSymbol(GV);
119   const Constant *C = GV->getInitializer();
120   unsigned Align = (unsigned)DL.getPreferredTypeAlignmentShift(C->getType());
121 
122   // Mark the start of the global
123   getTargetStreamer().emitCCTopData(GVSym->getName());
124 
125   switch (GV->getLinkage()) {
126   case GlobalValue::AppendingLinkage:
127     report_fatal_error("AppendingLinkage is not supported by this target!");
128   case GlobalValue::LinkOnceAnyLinkage:
129   case GlobalValue::LinkOnceODRLinkage:
130   case GlobalValue::WeakAnyLinkage:
131   case GlobalValue::WeakODRLinkage:
132   case GlobalValue::ExternalLinkage:
133   case GlobalValue::CommonLinkage:
134     emitArrayBound(GVSym, GV);
135     OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
136 
137     if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
138         GV->hasCommonLinkage())
139       OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Weak);
140     LLVM_FALLTHROUGH;
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 = DL.getTypeAllocSize(C->getType());
154   if (MAI->hasDotTypeDotSizeDirective()) {
155     OutStreamer->EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
156     OutStreamer->emitELFSize(cast<MCSymbolELF>(GVSym),
157                              MCConstantExpr::create(Size, OutContext));
158   }
159   OutStreamer->EmitLabel(GVSym);
160 
161   EmitGlobalConstant(DL, C);
162   // The ABI requires that unsigned scalar types smaller than 32 bits
163   // are padded to 32 bits.
164   if (Size < 4)
165     OutStreamer->EmitZeros(4 - Size);
166 
167   // Mark the end of the global
168   getTargetStreamer().emitCCBottomData(GVSym->getName());
169 }
170 
171 void XCoreAsmPrinter::EmitFunctionBodyStart() {
172   MCInstLowering.Initialize(&MF->getContext());
173 }
174 
175 /// EmitFunctionBodyEnd - Targets can override this to emit stuff after
176 /// the last basic block in the function.
177 void XCoreAsmPrinter::EmitFunctionBodyEnd() {
178   // Emit function end directives
179   getTargetStreamer().emitCCBottomFunction(CurrentFnSym->getName());
180 }
181 
182 void XCoreAsmPrinter::EmitFunctionEntryLabel() {
183   // Mark the start of the function
184   getTargetStreamer().emitCCTopFunction(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     MBB->getSymbol()->print(O, MAI);
202   }
203 }
204 
205 void XCoreAsmPrinter::printOperand(const MachineInstr *MI, int opNum,
206                                    raw_ostream &O) {
207   const DataLayout &DL = getDataLayout();
208   const MachineOperand &MO = MI->getOperand(opNum);
209   switch (MO.getType()) {
210   case MachineOperand::MO_Register:
211     O << XCoreInstPrinter::getRegisterName(MO.getReg());
212     break;
213   case MachineOperand::MO_Immediate:
214     O << MO.getImm();
215     break;
216   case MachineOperand::MO_MachineBasicBlock:
217     MO.getMBB()->getSymbol()->print(O, MAI);
218     break;
219   case MachineOperand::MO_GlobalAddress:
220     getSymbol(MO.getGlobal())->print(O, MAI);
221     break;
222   case MachineOperand::MO_ConstantPoolIndex:
223     O << DL.getPrivateGlobalPrefix() << "CPI" << getFunctionNumber() << '_'
224       << MO.getIndex();
225     break;
226   case MachineOperand::MO_BlockAddress:
227     GetBlockAddressSymbol(MO.getBlockAddress())->print(O, MAI);
228     break;
229   default:
230     llvm_unreachable("not implemented");
231   }
232 }
233 
234 /// PrintAsmOperand - Print out an operand for an inline asm expression.
235 ///
236 bool XCoreAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
237                                       unsigned AsmVariant,const char *ExtraCode,
238                                       raw_ostream &O) {
239   // Print the operand if there is no operand modifier.
240   if (!ExtraCode || !ExtraCode[0]) {
241     printOperand(MI, OpNo, O);
242     return false;
243   }
244 
245   // Otherwise fallback on the default implementation.
246   return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, O);
247 }
248 
249 bool XCoreAsmPrinter::
250 PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNum,
251                       unsigned AsmVariant, const char *ExtraCode,
252                       raw_ostream &O) {
253   if (ExtraCode && ExtraCode[0]) {
254     return true; // Unknown modifier.
255   }
256   printOperand(MI, OpNum, O);
257   O << '[';
258   printOperand(MI, OpNum + 1, O);
259   O << ']';
260   return false;
261 }
262 
263 void XCoreAsmPrinter::EmitInstruction(const MachineInstr *MI) {
264   SmallString<128> Str;
265   raw_svector_ostream O(Str);
266 
267   switch (MI->getOpcode()) {
268   case XCore::DBG_VALUE:
269     llvm_unreachable("Should be handled target independently");
270   case XCore::ADD_2rus:
271     if (MI->getOperand(2).getImm() == 0) {
272       O << "\tmov "
273         << XCoreInstPrinter::getRegisterName(MI->getOperand(0).getReg()) << ", "
274         << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg());
275       OutStreamer->EmitRawText(O.str());
276       return;
277     }
278     break;
279   case XCore::BR_JT:
280   case XCore::BR_JT32:
281     O << "\tbru "
282       << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg()) << '\n';
283     if (MI->getOpcode() == XCore::BR_JT)
284       printInlineJT(MI, 0, O);
285     else
286       printInlineJT32(MI, 0, O);
287     O << '\n';
288     OutStreamer->EmitRawText(O.str());
289     return;
290   }
291 
292   MCInst TmpInst;
293   MCInstLowering.Lower(MI, TmpInst);
294 
295   EmitToStreamer(*OutStreamer, TmpInst);
296 }
297 
298 // Force static initialization.
299 extern "C" void LLVMInitializeXCoreAsmPrinter() {
300   RegisterAsmPrinter<XCoreAsmPrinter> X(getTheXCoreTarget());
301 }
302