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,
59                              std::unique_ptr<MCStreamer> Streamer)
60         : AsmPrinter(TM, std::move(Streamer)),
61           Subtarget(TM.getSubtarget<XCoreSubtarget>()), MCInstLowering(*this) {}
62 
63     const char *getPassName() const override {
64       return "XCore Assembly Printer";
65     }
66 
67     void printInlineJT(const MachineInstr *MI, int opNum, raw_ostream &O,
68                        const std::string &directive = ".jmptable");
69     void printInlineJT32(const MachineInstr *MI, int opNum, raw_ostream &O) {
70       printInlineJT(MI, opNum, O, ".jmptable32");
71     }
72     void printOperand(const MachineInstr *MI, int opNum, raw_ostream &O);
73     bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
74                          unsigned AsmVariant, const char *ExtraCode,
75                          raw_ostream &O) override;
76     bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNum,
77                                unsigned AsmVariant, const char *ExtraCode,
78                                raw_ostream &O) override;
79 
80     void emitArrayBound(MCSymbol *Sym, const GlobalVariable *GV);
81     void EmitGlobalVariable(const GlobalVariable *GV) override;
82 
83     void EmitFunctionEntryLabel() override;
84     void EmitInstruction(const MachineInstr *MI) override;
85     void EmitFunctionBodyStart() override;
86     void EmitFunctionBodyEnd() override;
87   };
88 } // end of anonymous namespace
89 
90 XCoreTargetStreamer &XCoreAsmPrinter::getTargetStreamer() {
91   return static_cast<XCoreTargetStreamer&>(*OutStreamer.getTargetStreamer());
92 }
93 
94 void XCoreAsmPrinter::emitArrayBound(MCSymbol *Sym, const GlobalVariable *GV) {
95   assert( ( GV->hasExternalLinkage() || GV->hasWeakLinkage() ||
96             GV->hasLinkOnceLinkage() || GV->hasCommonLinkage() ) &&
97           "Unexpected linkage");
98   if (ArrayType *ATy = dyn_cast<ArrayType>(
99                         cast<PointerType>(GV->getType())->getElementType())) {
100 
101     MCSymbol *SymGlob = OutContext.GetOrCreateSymbol(
102                           Twine(Sym->getName() + StringRef(".globound")));
103     OutStreamer.EmitSymbolAttribute(SymGlob, MCSA_Global);
104     OutStreamer.EmitAssignment(SymGlob,
105                                MCConstantExpr::Create(ATy->getNumElements(),
106                                                       OutContext));
107     if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
108         GV->hasCommonLinkage()) {
109       OutStreamer.EmitSymbolAttribute(SymGlob, MCSA_Weak);
110     }
111   }
112 }
113 
114 void XCoreAsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
115   // Check to see if this is a special global used by LLVM, if so, emit it.
116   if (!GV->hasInitializer() ||
117       EmitSpecialLLVMGlobal(GV))
118     return;
119 
120   const DataLayout *TD = TM.getSubtargetImpl()->getDataLayout();
121   OutStreamer.SwitchSection(
122       getObjFileLowering().SectionForGlobal(GV, *Mang, TM));
123 
124   MCSymbol *GVSym = getSymbol(GV);
125   const Constant *C = GV->getInitializer();
126   unsigned Align = (unsigned)TD->getPreferredTypeAlignmentShift(C->getType());
127 
128   // Mark the start of the global
129   getTargetStreamer().emitCCTopData(GVSym->getName());
130 
131   switch (GV->getLinkage()) {
132   case GlobalValue::AppendingLinkage:
133     report_fatal_error("AppendingLinkage is not supported by this target!");
134   case GlobalValue::LinkOnceAnyLinkage:
135   case GlobalValue::LinkOnceODRLinkage:
136   case GlobalValue::WeakAnyLinkage:
137   case GlobalValue::WeakODRLinkage:
138   case GlobalValue::ExternalLinkage:
139   case GlobalValue::CommonLinkage:
140     emitArrayBound(GVSym, GV);
141     OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
142 
143     if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
144         GV->hasCommonLinkage())
145       OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak);
146     // FALL THROUGH
147   case GlobalValue::InternalLinkage:
148   case GlobalValue::PrivateLinkage:
149     break;
150   default:
151     llvm_unreachable("Unknown linkage type!");
152   }
153 
154   EmitAlignment(Align > 2 ? Align : 2, GV);
155 
156   if (GV->isThreadLocal()) {
157     report_fatal_error("TLS is not supported by this target!");
158   }
159   unsigned Size = TD->getTypeAllocSize(C->getType());
160   if (MAI->hasDotTypeDotSizeDirective()) {
161     OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
162     OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext));
163   }
164   OutStreamer.EmitLabel(GVSym);
165 
166   EmitGlobalConstant(C);
167   // The ABI requires that unsigned scalar types smaller than 32 bits
168   // are padded to 32 bits.
169   if (Size < 4)
170     OutStreamer.EmitZeros(4 - Size);
171 
172   // Mark the end of the global
173   getTargetStreamer().emitCCBottomData(GVSym->getName());
174 }
175 
176 void XCoreAsmPrinter::EmitFunctionBodyStart() {
177   MCInstLowering.Initialize(Mang, &MF->getContext());
178 }
179 
180 /// EmitFunctionBodyEnd - Targets can override this to emit stuff after
181 /// the last basic block in the function.
182 void XCoreAsmPrinter::EmitFunctionBodyEnd() {
183   // Emit function end directives
184   getTargetStreamer().emitCCBottomFunction(CurrentFnSym->getName());
185 }
186 
187 void XCoreAsmPrinter::EmitFunctionEntryLabel() {
188   // Mark the start of the function
189   getTargetStreamer().emitCCTopFunction(CurrentFnSym->getName());
190   OutStreamer.EmitLabel(CurrentFnSym);
191 }
192 
193 void XCoreAsmPrinter::
194 printInlineJT(const MachineInstr *MI, int opNum, raw_ostream &O,
195               const std::string &directive) {
196   unsigned JTI = MI->getOperand(opNum).getIndex();
197   const MachineFunction *MF = MI->getParent()->getParent();
198   const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
199   const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
200   const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
201   O << "\t" << directive << " ";
202   for (unsigned i = 0, e = JTBBs.size(); i != e; ++i) {
203     MachineBasicBlock *MBB = JTBBs[i];
204     if (i > 0)
205       O << ",";
206     O << *MBB->getSymbol();
207   }
208 }
209 
210 void XCoreAsmPrinter::printOperand(const MachineInstr *MI, int opNum,
211                                    raw_ostream &O) {
212   const DataLayout *DL = TM.getSubtargetImpl()->getDataLayout();
213   const MachineOperand &MO = MI->getOperand(opNum);
214   switch (MO.getType()) {
215   case MachineOperand::MO_Register:
216     O << XCoreInstPrinter::getRegisterName(MO.getReg());
217     break;
218   case MachineOperand::MO_Immediate:
219     O << MO.getImm();
220     break;
221   case MachineOperand::MO_MachineBasicBlock:
222     O << *MO.getMBB()->getSymbol();
223     break;
224   case MachineOperand::MO_GlobalAddress:
225     O << *getSymbol(MO.getGlobal());
226     break;
227   case MachineOperand::MO_ConstantPoolIndex:
228     O << DL->getPrivateGlobalPrefix() << "CPI" << getFunctionNumber()
229       << '_' << MO.getIndex();
230     break;
231   case MachineOperand::MO_BlockAddress:
232     O << *GetBlockAddressSymbol(MO.getBlockAddress());
233     break;
234   default:
235     llvm_unreachable("not implemented");
236   }
237 }
238 
239 /// PrintAsmOperand - Print out an operand for an inline asm expression.
240 ///
241 bool XCoreAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
242                                       unsigned AsmVariant,const char *ExtraCode,
243                                       raw_ostream &O) {
244   // Print the operand if there is no operand modifier.
245   if (!ExtraCode || !ExtraCode[0]) {
246     printOperand(MI, OpNo, O);
247     return false;
248   }
249 
250   // Otherwise fallback on the default implementation.
251   return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, O);
252 }
253 
254 bool XCoreAsmPrinter::
255 PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNum,
256                       unsigned AsmVariant, const char *ExtraCode,
257                       raw_ostream &O) {
258   if (ExtraCode && ExtraCode[0]) {
259     return true; // Unknown modifier.
260   }
261   printOperand(MI, OpNum, O);
262   O << '[';
263   printOperand(MI, OpNum + 1, O);
264   O << ']';
265   return false;
266 }
267 
268 void XCoreAsmPrinter::EmitInstruction(const MachineInstr *MI) {
269   SmallString<128> Str;
270   raw_svector_ostream O(Str);
271 
272   switch (MI->getOpcode()) {
273   case XCore::DBG_VALUE:
274     llvm_unreachable("Should be handled target independently");
275   case XCore::ADD_2rus:
276     if (MI->getOperand(2).getImm() == 0) {
277       O << "\tmov "
278         << XCoreInstPrinter::getRegisterName(MI->getOperand(0).getReg()) << ", "
279         << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg());
280       OutStreamer.EmitRawText(O.str());
281       return;
282     }
283     break;
284   case XCore::BR_JT:
285   case XCore::BR_JT32:
286     O << "\tbru "
287       << XCoreInstPrinter::getRegisterName(MI->getOperand(1).getReg()) << '\n';
288     if (MI->getOpcode() == XCore::BR_JT)
289       printInlineJT(MI, 0, O);
290     else
291       printInlineJT32(MI, 0, O);
292     O << '\n';
293     OutStreamer.EmitRawText(O.str());
294     return;
295   }
296 
297   MCInst TmpInst;
298   MCInstLowering.Lower(MI, TmpInst);
299 
300   EmitToStreamer(OutStreamer, TmpInst);
301 }
302 
303 // Force static initialization.
304 extern "C" void LLVMInitializeXCoreAsmPrinter() {
305   RegisterAsmPrinter<XCoreAsmPrinter> X(TheXCoreTarget);
306 }
307