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/MCSymbol.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     const XCoreSubtarget &Subtarget;
54     XCoreMCInstLower MCInstLowering;
55     XCoreTargetStreamer &getTargetStreamer();
56 
57   public:
58     explicit XCoreAsmPrinter(TargetMachine &TM, MCStreamer &Streamer)
59       : AsmPrinter(TM, Streamer), Subtarget(TM.getSubtarget<XCoreSubtarget>()),
60         MCInstLowering(*this) {}
61 
62     const char *getPassName() const override {
63       return "XCore Assembly Printer";
64     }
65 
66     void printInlineJT(const MachineInstr *MI, int opNum, raw_ostream &O,
67                        const std::string &directive = ".jmptable");
68     void printInlineJT32(const MachineInstr *MI, int opNum, raw_ostream &O) {
69       printInlineJT(MI, opNum, O, ".jmptable32");
70     }
71     void printOperand(const MachineInstr *MI, int opNum, raw_ostream &O);
72     bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
73                          unsigned AsmVariant, const char *ExtraCode,
74                          raw_ostream &O) override;
75     bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNum,
76                                unsigned AsmVariant, const char *ExtraCode,
77                                raw_ostream &O) override;
78 
79     void emitArrayBound(MCSymbol *Sym, const GlobalVariable *GV);
80     void EmitGlobalVariable(const GlobalVariable *GV) override;
81 
82     void EmitFunctionEntryLabel() override;
83     void EmitInstruction(const MachineInstr *MI) override;
84     void EmitFunctionBodyStart() override;
85     void EmitFunctionBodyEnd() override;
86   };
87 } // end of anonymous namespace
88 
89 XCoreTargetStreamer &XCoreAsmPrinter::getTargetStreamer() {
90   return static_cast<XCoreTargetStreamer&>(*OutStreamer.getTargetStreamer());
91 }
92 
93 void XCoreAsmPrinter::emitArrayBound(MCSymbol *Sym, const GlobalVariable *GV) {
94   assert( ( GV->hasExternalLinkage() || GV->hasWeakLinkage() ||
95             GV->hasLinkOnceLinkage() || GV->hasCommonLinkage() ) &&
96           "Unexpected linkage");
97   if (ArrayType *ATy = dyn_cast<ArrayType>(
98                         cast<PointerType>(GV->getType())->getElementType())) {
99 
100     MCSymbol *SymGlob = OutContext.GetOrCreateSymbol(
101                           Twine(Sym->getName() + StringRef(".globound")));
102     OutStreamer.EmitSymbolAttribute(SymGlob, MCSA_Global);
103     OutStreamer.EmitAssignment(SymGlob,
104                                MCConstantExpr::Create(ATy->getNumElements(),
105                                                       OutContext));
106     if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
107         GV->hasCommonLinkage()) {
108       OutStreamer.EmitSymbolAttribute(SymGlob, MCSA_Weak);
109     }
110   }
111 }
112 
113 void XCoreAsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
114   // Check to see if this is a special global used by LLVM, if so, emit it.
115   if (!GV->hasInitializer() ||
116       EmitSpecialLLVMGlobal(GV))
117     return;
118 
119   const DataLayout *TD = TM.getSubtargetImpl()->getDataLayout();
120   OutStreamer.SwitchSection(
121       getObjFileLowering().SectionForGlobal(GV, *Mang, TM));
122 
123   MCSymbol *GVSym = getSymbol(GV);
124   const Constant *C = GV->getInitializer();
125   unsigned Align = (unsigned)TD->getPreferredTypeAlignmentShift(C->getType());
126 
127   // Mark the start of the global
128   getTargetStreamer().emitCCTopData(GVSym->getName());
129 
130   switch (GV->getLinkage()) {
131   case GlobalValue::AppendingLinkage:
132     report_fatal_error("AppendingLinkage is not supported by this target!");
133   case GlobalValue::LinkOnceAnyLinkage:
134   case GlobalValue::LinkOnceODRLinkage:
135   case GlobalValue::WeakAnyLinkage:
136   case GlobalValue::WeakODRLinkage:
137   case GlobalValue::ExternalLinkage:
138   case GlobalValue::CommonLinkage:
139     emitArrayBound(GVSym, GV);
140     OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
141 
142     if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
143         GV->hasCommonLinkage())
144       OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak);
145     // FALL THROUGH
146   case GlobalValue::InternalLinkage:
147   case GlobalValue::PrivateLinkage:
148     break;
149   default:
150     llvm_unreachable("Unknown linkage type!");
151   }
152 
153   EmitAlignment(Align > 2 ? Align : 2, GV);
154 
155   if (GV->isThreadLocal()) {
156     report_fatal_error("TLS is not supported by this target!");
157   }
158   unsigned Size = TD->getTypeAllocSize(C->getType());
159   if (MAI->hasDotTypeDotSizeDirective()) {
160     OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
161     OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext));
162   }
163   OutStreamer.EmitLabel(GVSym);
164 
165   EmitGlobalConstant(C);
166   // The ABI requires that unsigned scalar types smaller than 32 bits
167   // are padded to 32 bits.
168   if (Size < 4)
169     OutStreamer.EmitZeros(4 - Size);
170 
171   // Mark the end of the global
172   getTargetStreamer().emitCCBottomData(GVSym->getName());
173 }
174 
175 void XCoreAsmPrinter::EmitFunctionBodyStart() {
176   MCInstLowering.Initialize(Mang, &MF->getContext());
177 }
178 
179 /// EmitFunctionBodyEnd - Targets can override this to emit stuff after
180 /// the last basic block in the function.
181 void XCoreAsmPrinter::EmitFunctionBodyEnd() {
182   // Emit function end directives
183   getTargetStreamer().emitCCBottomFunction(CurrentFnSym->getName());
184 }
185 
186 void XCoreAsmPrinter::EmitFunctionEntryLabel() {
187   // Mark the start of the function
188   getTargetStreamer().emitCCTopFunction(CurrentFnSym->getName());
189   OutStreamer.EmitLabel(CurrentFnSym);
190 }
191 
192 void XCoreAsmPrinter::
193 printInlineJT(const MachineInstr *MI, int opNum, raw_ostream &O,
194               const std::string &directive) {
195   unsigned JTI = MI->getOperand(opNum).getIndex();
196   const MachineFunction *MF = MI->getParent()->getParent();
197   const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
198   const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
199   const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
200   O << "\t" << directive << " ";
201   for (unsigned i = 0, e = JTBBs.size(); i != e; ++i) {
202     MachineBasicBlock *MBB = JTBBs[i];
203     if (i > 0)
204       O << ",";
205     O << *MBB->getSymbol();
206   }
207 }
208 
209 void XCoreAsmPrinter::printOperand(const MachineInstr *MI, int opNum,
210                                    raw_ostream &O) {
211   const DataLayout *DL = TM.getSubtargetImpl()->getDataLayout();
212   const MachineOperand &MO = MI->getOperand(opNum);
213   switch (MO.getType()) {
214   case MachineOperand::MO_Register:
215     O << XCoreInstPrinter::getRegisterName(MO.getReg());
216     break;
217   case MachineOperand::MO_Immediate:
218     O << MO.getImm();
219     break;
220   case MachineOperand::MO_MachineBasicBlock:
221     O << *MO.getMBB()->getSymbol();
222     break;
223   case MachineOperand::MO_GlobalAddress:
224     O << *getSymbol(MO.getGlobal());
225     break;
226   case MachineOperand::MO_ConstantPoolIndex:
227     O << DL->getPrivateGlobalPrefix() << "CPI" << 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 bool XCoreAsmPrinter::
254 PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNum,
255                       unsigned AsmVariant, const char *ExtraCode,
256                       raw_ostream &O) {
257   if (ExtraCode && ExtraCode[0]) {
258     return true; // Unknown modifier.
259   }
260   printOperand(MI, OpNum, O);
261   O << '[';
262   printOperand(MI, OpNum + 1, O);
263   O << ']';
264   return false;
265 }
266 
267 void XCoreAsmPrinter::EmitInstruction(const MachineInstr *MI) {
268   SmallString<128> Str;
269   raw_svector_ostream O(Str);
270 
271   switch (MI->getOpcode()) {
272   case XCore::DBG_VALUE:
273     llvm_unreachable("Should be handled target independently");
274   case XCore::ADD_2rus:
275     if (MI->getOperand(2).getImm() == 0) {
276       O << "\tmov "
277         << XCoreInstPrinter::getRegisterName(MI->getOperand(0).getReg()) << ", "
278         << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg());
279       OutStreamer.EmitRawText(O.str());
280       return;
281     }
282     break;
283   case XCore::BR_JT:
284   case XCore::BR_JT32:
285     O << "\tbru "
286       << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg()) << '\n';
287     if (MI->getOpcode() == XCore::BR_JT)
288       printInlineJT(MI, 0, O);
289     else
290       printInlineJT32(MI, 0, O);
291     O << '\n';
292     OutStreamer.EmitRawText(O.str());
293     return;
294   }
295 
296   MCInst TmpInst;
297   MCInstLowering.Lower(MI, TmpInst);
298 
299   EmitToStreamer(OutStreamer, TmpInst);
300 }
301 
302 // Force static initialization.
303 extern "C" void LLVMInitializeXCoreAsmPrinter() {
304   RegisterAsmPrinter<XCoreAsmPrinter> X(TheXCoreTarget);
305 }
306