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 "InstPrinter/XCoreInstPrinter.h"
16 #include "XCore.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(GVSym, MCConstantExpr::create(Size, OutContext));
157   }
158   OutStreamer->EmitLabel(GVSym);
159 
160   EmitGlobalConstant(DL, 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(&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     MBB->getSymbol()->print(O, MAI);
201   }
202 }
203 
204 void XCoreAsmPrinter::printOperand(const MachineInstr *MI, int opNum,
205                                    raw_ostream &O) {
206   const DataLayout &DL = 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     MO.getMBB()->getSymbol()->print(O, MAI);
217     break;
218   case MachineOperand::MO_GlobalAddress:
219     getSymbol(MO.getGlobal())->print(O, MAI);
220     break;
221   case MachineOperand::MO_ConstantPoolIndex:
222     O << DL.getPrivateGlobalPrefix() << "CPI" << getFunctionNumber() << '_'
223       << MO.getIndex();
224     break;
225   case MachineOperand::MO_BlockAddress:
226     GetBlockAddressSymbol(MO.getBlockAddress())->print(O, MAI);
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 bool XCoreAsmPrinter::
249 PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNum,
250                       unsigned AsmVariant, const char *ExtraCode,
251                       raw_ostream &O) {
252   if (ExtraCode && ExtraCode[0]) {
253     return true; // Unknown modifier.
254   }
255   printOperand(MI, OpNum, O);
256   O << '[';
257   printOperand(MI, OpNum + 1, O);
258   O << ']';
259   return false;
260 }
261 
262 void XCoreAsmPrinter::EmitInstruction(const MachineInstr *MI) {
263   SmallString<128> Str;
264   raw_svector_ostream O(Str);
265 
266   switch (MI->getOpcode()) {
267   case XCore::DBG_VALUE:
268     llvm_unreachable("Should be handled target independently");
269   case XCore::ADD_2rus:
270     if (MI->getOperand(2).getImm() == 0) {
271       O << "\tmov "
272         << XCoreInstPrinter::getRegisterName(MI->getOperand(0).getReg()) << ", "
273         << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg());
274       OutStreamer->EmitRawText(O.str());
275       return;
276     }
277     break;
278   case XCore::BR_JT:
279   case XCore::BR_JT32:
280     O << "\tbru "
281       << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg()) << '\n';
282     if (MI->getOpcode() == XCore::BR_JT)
283       printInlineJT(MI, 0, O);
284     else
285       printInlineJT32(MI, 0, O);
286     O << '\n';
287     OutStreamer->EmitRawText(O.str());
288     return;
289   }
290 
291   MCInst TmpInst;
292   MCInstLowering.Lower(MI, TmpInst);
293 
294   EmitToStreamer(*OutStreamer, TmpInst);
295 }
296 
297 // Force static initialization.
298 extern "C" void LLVMInitializeXCoreAsmPrinter() {
299   RegisterAsmPrinter<XCoreAsmPrinter> X(getTheXCoreTarget());
300 }
301