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 "XCoreInstrInfo.h"
18 #include "XCoreSubtarget.h"
19 #include "XCoreTargetMachine.h"
20 #include "llvm/Constants.h"
21 #include "llvm/DerivedTypes.h"
22 #include "llvm/Module.h"
23 #include "llvm/CodeGen/AsmPrinter.h"
24 #include "llvm/CodeGen/DwarfWriter.h"
25 #include "llvm/CodeGen/MachineModuleInfo.h"
26 #include "llvm/CodeGen/MachineFunctionPass.h"
27 #include "llvm/CodeGen/MachineConstantPool.h"
28 #include "llvm/CodeGen/MachineInstr.h"
29 #include "llvm/Target/TargetAsmInfo.h"
30 #include "llvm/Target/TargetData.h"
31 #include "llvm/Support/Mangler.h"
32 #include "llvm/ADT/Statistic.h"
33 #include "llvm/ADT/StringExtras.h"
34 #include "llvm/Support/CommandLine.h"
35 #include "llvm/Support/MathExtras.h"
36 #include "llvm/Support/raw_ostream.h"
37 #include <algorithm>
38 #include <cctype>
39 using namespace llvm;
40 
41 STATISTIC(EmittedInsts, "Number of machine instrs printed");
42 
43 static cl::opt<std::string> FileDirective("xcore-file-directive", cl::Optional,
44   cl::desc("Output a file directive into the assembly file"),
45   cl::Hidden,
46   cl::value_desc("filename"),
47   cl::init(""));
48 
49 static cl::opt<unsigned> MaxThreads("xcore-max-threads", cl::Optional,
50   cl::desc("Maximum number of threads (for emulation thread-local storage)"),
51   cl::Hidden,
52   cl::value_desc("number"),
53   cl::init(8));
54 
55 namespace {
56   class VISIBILITY_HIDDEN XCoreAsmPrinter : public AsmPrinter {
57     DwarfWriter *DW;
58     const XCoreSubtarget &Subtarget;
59   public:
60     explicit XCoreAsmPrinter(raw_ostream &O, XCoreTargetMachine &TM,
61                              const TargetAsmInfo *T, CodeGenOpt::Level OL,
62                              bool V)
63       : AsmPrinter(O, TM, T, OL, V), DW(0),
64         Subtarget(*TM.getSubtargetImpl()) {}
65 
66     virtual const char *getPassName() const {
67       return "XCore Assembly Printer";
68     }
69 
70     void printMemOperand(const MachineInstr *MI, int opNum);
71     void printOperand(const MachineInstr *MI, int opNum);
72     bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
73                         unsigned AsmVariant, const char *ExtraCode);
74 
75     void emitFileDirective(const std::string &filename);
76     void emitGlobalDirective(const std::string &name);
77     void emitExternDirective(const std::string &name);
78 
79     void emitArrayBound(const std::string &name, const GlobalVariable *GV);
80     void emitGlobal(const GlobalVariable *GV);
81 
82     void emitFunctionStart(MachineFunction &MF);
83     void emitFunctionEnd(MachineFunction &MF);
84 
85     bool printInstruction(const MachineInstr *MI);  // autogenerated.
86     void printMachineInstruction(const MachineInstr *MI);
87     bool runOnMachineFunction(MachineFunction &F);
88     bool doInitialization(Module &M);
89     bool doFinalization(Module &M);
90 
91     void getAnalysisUsage(AnalysisUsage &AU) const {
92       AsmPrinter::getAnalysisUsage(AU);
93       AU.setPreservesAll();
94       AU.addRequired<MachineModuleInfo>();
95       AU.addRequired<DwarfWriter>();
96     }
97   };
98 } // end of anonymous namespace
99 
100 #include "XCoreGenAsmWriter.inc"
101 
102 /// createXCoreCodePrinterPass - Returns a pass that prints the XCore
103 /// assembly code for a MachineFunction to the given output stream,
104 /// using the given target machine description.  This should work
105 /// regardless of whether the function is in SSA form.
106 ///
107 FunctionPass *llvm::createXCoreCodePrinterPass(raw_ostream &o,
108                                                XCoreTargetMachine &tm,
109                                                CodeGenOpt::Level OptLevel,
110                                                bool verbose) {
111   return new XCoreAsmPrinter(o, tm, tm.getTargetAsmInfo(), OptLevel, verbose);
112 }
113 
114 // PrintEscapedString - Print each character of the specified string, escaping
115 // it if it is not printable or if it is an escape char.
116 static void PrintEscapedString(const std::string &Str, raw_ostream &Out) {
117   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
118     unsigned char C = Str[i];
119     if (isprint(C) && C != '"' && C != '\\') {
120       Out << C;
121     } else {
122       Out << '\\'
123           << (char) ((C/16  < 10) ? ( C/16 +'0') : ( C/16 -10+'A'))
124           << (char)(((C&15) < 10) ? ((C&15)+'0') : ((C&15)-10+'A'));
125     }
126   }
127 }
128 
129 void XCoreAsmPrinter::
130 emitFileDirective(const std::string &name)
131 {
132   O << "\t.file\t\"";
133   PrintEscapedString(name, O);
134   O << "\"\n";
135 }
136 
137 void XCoreAsmPrinter::
138 emitGlobalDirective(const std::string &name)
139 {
140   O << TAI->getGlobalDirective() << name;
141   O << "\n";
142 }
143 
144 void XCoreAsmPrinter::
145 emitExternDirective(const std::string &name)
146 {
147   O << "\t.extern\t" << name;
148   O << '\n';
149 }
150 
151 void XCoreAsmPrinter::
152 emitArrayBound(const std::string &name, const GlobalVariable *GV)
153 {
154   assert(((GV->hasExternalLinkage() ||
155     GV->hasWeakLinkage()) ||
156     GV->hasLinkOnceLinkage()) && "Unexpected linkage");
157   if (const ArrayType *ATy = dyn_cast<ArrayType>(
158     cast<PointerType>(GV->getType())->getElementType()))
159   {
160     O << TAI->getGlobalDirective() << name << ".globound" << "\n";
161     O << TAI->getSetDirective() << name << ".globound" << ","
162       << ATy->getNumElements() << "\n";
163     if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage()) {
164       // TODO Use COMDAT groups for LinkOnceLinkage
165       O << TAI->getWeakDefDirective() << name << ".globound" << "\n";
166     }
167   }
168 }
169 
170 void XCoreAsmPrinter::
171 emitGlobal(const GlobalVariable *GV)
172 {
173   const TargetData *TD = TM.getTargetData();
174 
175   if (GV->hasInitializer()) {
176     // Check to see if this is a special global used by LLVM, if so, emit it.
177     if (EmitSpecialLLVMGlobal(GV))
178       return;
179 
180     SwitchToSection(TAI->SectionForGlobal(GV));
181 
182     std::string name = Mang->getValueName(GV);
183     Constant *C = GV->getInitializer();
184     unsigned Align = (unsigned)TD->getPreferredTypeAlignmentShift(C->getType());
185 
186     // Mark the start of the global
187     O << "\t.cc_top " << name << ".data," << name << "\n";
188 
189     switch (GV->getLinkage()) {
190     case GlobalValue::AppendingLinkage:
191       cerr << "AppendingLinkage is not supported by this target!\n";
192       abort();
193     case GlobalValue::LinkOnceAnyLinkage:
194     case GlobalValue::LinkOnceODRLinkage:
195     case GlobalValue::WeakAnyLinkage:
196     case GlobalValue::WeakODRLinkage:
197     case GlobalValue::ExternalLinkage:
198       emitArrayBound(name, GV);
199       emitGlobalDirective(name);
200       // TODO Use COMDAT groups for LinkOnceLinkage
201       if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage()) {
202         O << TAI->getWeakDefDirective() << name << "\n";
203       }
204       // FALL THROUGH
205     case GlobalValue::InternalLinkage:
206     case GlobalValue::PrivateLinkage:
207       break;
208     case GlobalValue::GhostLinkage:
209       cerr << "Should not have any unmaterialized functions!\n";
210       abort();
211     case GlobalValue::DLLImportLinkage:
212       cerr << "DLLImport linkage is not supported by this target!\n";
213       abort();
214     case GlobalValue::DLLExportLinkage:
215       cerr << "DLLExport linkage is not supported by this target!\n";
216       abort();
217     default:
218       assert(0 && "Unknown linkage type!");
219     }
220 
221     EmitAlignment(Align, GV, 2);
222 
223     unsigned Size = TD->getTypeAllocSize(C->getType());
224     if (GV->isThreadLocal()) {
225       Size *= MaxThreads;
226     }
227     if (TAI->hasDotTypeDotSizeDirective()) {
228       O << "\t.type " << name << ",@object\n";
229       O << "\t.size " << name << "," << Size << "\n";
230     }
231     O << name << ":\n";
232 
233     EmitGlobalConstant(C);
234     if (GV->isThreadLocal()) {
235       for (unsigned i = 1; i < MaxThreads; ++i) {
236         EmitGlobalConstant(C);
237       }
238     }
239     if (Size < 4) {
240       // The ABI requires that unsigned scalar types smaller than 32 bits
241       // are are padded to 32 bits.
242       EmitZeros(4 - Size);
243     }
244 
245     // Mark the end of the global
246     O << "\t.cc_bottom " << name << ".data\n";
247   } else {
248     if (GV->hasExternalWeakLinkage())
249       ExtWeakSymbols.insert(GV);
250   }
251 }
252 
253 /// Emit the directives on the start of functions
254 void XCoreAsmPrinter::
255 emitFunctionStart(MachineFunction &MF)
256 {
257   // Print out the label for the function.
258   const Function *F = MF.getFunction();
259 
260   SwitchToSection(TAI->SectionForGlobal(F));
261 
262   // Mark the start of the function
263   O << "\t.cc_top " << CurrentFnName << ".function," << CurrentFnName << "\n";
264 
265   switch (F->getLinkage()) {
266   default: assert(0 && "Unknown linkage type!");
267   case Function::InternalLinkage:  // Symbols default to internal.
268   case Function::PrivateLinkage:
269     break;
270   case Function::ExternalLinkage:
271     emitGlobalDirective(CurrentFnName);
272     break;
273   case Function::LinkOnceAnyLinkage:
274   case Function::LinkOnceODRLinkage:
275   case Function::WeakAnyLinkage:
276   case Function::WeakODRLinkage:
277     // TODO Use COMDAT groups for LinkOnceLinkage
278     O << TAI->getGlobalDirective() << CurrentFnName << "\n";
279     O << TAI->getWeakDefDirective() << CurrentFnName << "\n";
280     break;
281   }
282   // (1 << 1) byte aligned
283   EmitAlignment(1, F, 1);
284   if (TAI->hasDotTypeDotSizeDirective()) {
285     O << "\t.type " << CurrentFnName << ",@function\n";
286   }
287   O << CurrentFnName << ":\n";
288 }
289 
290 /// Emit the directives on the end of functions
291 void XCoreAsmPrinter::
292 emitFunctionEnd(MachineFunction &MF)
293 {
294   // Mark the end of the function
295   O << "\t.cc_bottom " << CurrentFnName << ".function\n";
296 }
297 
298 /// runOnMachineFunction - This uses the printMachineInstruction()
299 /// method to print assembly for each instruction.
300 ///
301 bool XCoreAsmPrinter::runOnMachineFunction(MachineFunction &MF)
302 {
303   this->MF = &MF;
304 
305   SetupMachineFunction(MF);
306 
307   // Print out constants referenced by the function
308   EmitConstantPool(MF.getConstantPool());
309 
310   // Print out jump tables referenced by the function
311   EmitJumpTableInfo(MF.getJumpTableInfo(), MF);
312 
313   // Emit the function start directives
314   emitFunctionStart(MF);
315 
316   // Emit pre-function debug information.
317   DW->BeginFunction(&MF);
318 
319   // Print out code for the function.
320   for (MachineFunction::const_iterator I = MF.begin(), E = MF.end();
321        I != E; ++I) {
322 
323     // Print a label for the basic block.
324     if (I != MF.begin()) {
325       printBasicBlockLabel(I, true , true);
326       O << '\n';
327     }
328 
329     for (MachineBasicBlock::const_iterator II = I->begin(), E = I->end();
330          II != E; ++II) {
331       // Print the assembly for the instruction.
332       O << "\t";
333       printMachineInstruction(II);
334     }
335 
336     // Each Basic Block is separated by a newline
337     O << '\n';
338   }
339 
340   // Emit function end directives
341   emitFunctionEnd(MF);
342 
343   // Emit post-function debug information.
344   DW->EndFunction(&MF);
345 
346   // We didn't modify anything.
347   return false;
348 }
349 
350 void XCoreAsmPrinter::printMemOperand(const MachineInstr *MI, int opNum)
351 {
352   printOperand(MI, opNum);
353 
354   if (MI->getOperand(opNum+1).isImm()
355     && MI->getOperand(opNum+1).getImm() == 0)
356     return;
357 
358   O << "+";
359   printOperand(MI, opNum+1);
360 }
361 
362 void XCoreAsmPrinter::printOperand(const MachineInstr *MI, int opNum) {
363   const MachineOperand &MO = MI->getOperand(opNum);
364   switch (MO.getType()) {
365   case MachineOperand::MO_Register:
366     if (TargetRegisterInfo::isPhysicalRegister(MO.getReg()))
367       O << TM.getRegisterInfo()->get(MO.getReg()).AsmName;
368     else
369       assert(0 && "not implemented");
370     break;
371   case MachineOperand::MO_Immediate:
372     O << MO.getImm();
373     break;
374   case MachineOperand::MO_MachineBasicBlock:
375     printBasicBlockLabel(MO.getMBB());
376     break;
377   case MachineOperand::MO_GlobalAddress:
378     {
379       const GlobalValue *GV = MO.getGlobal();
380       O << Mang->getValueName(GV);
381       if (GV->hasExternalWeakLinkage())
382         ExtWeakSymbols.insert(GV);
383     }
384     break;
385   case MachineOperand::MO_ExternalSymbol:
386     O << MO.getSymbolName();
387     break;
388   case MachineOperand::MO_ConstantPoolIndex:
389     O << TAI->getPrivateGlobalPrefix() << "CPI" << getFunctionNumber()
390       << '_' << MO.getIndex();
391     break;
392   case MachineOperand::MO_JumpTableIndex:
393     O << TAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber()
394       << '_' << MO.getIndex();
395     break;
396   default:
397     assert(0 && "not implemented");
398   }
399 }
400 
401 /// PrintAsmOperand - Print out an operand for an inline asm expression.
402 ///
403 bool XCoreAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
404                                       unsigned AsmVariant,
405                                       const char *ExtraCode) {
406   printOperand(MI, OpNo);
407   return false;
408 }
409 
410 void XCoreAsmPrinter::printMachineInstruction(const MachineInstr *MI) {
411   ++EmittedInsts;
412 
413   // Check for mov mnemonic
414   unsigned src, dst, srcSR, dstSR;
415   if (TM.getInstrInfo()->isMoveInstr(*MI, src, dst, srcSR, dstSR)) {
416     O << "\tmov ";
417     O << TM.getRegisterInfo()->get(dst).AsmName;
418     O << ", ";
419     O << TM.getRegisterInfo()->get(src).AsmName;
420     O << "\n";
421     return;
422   }
423   if (printInstruction(MI)) {
424     return;
425   }
426   assert(0 && "Unhandled instruction in asm writer!");
427 }
428 
429 bool XCoreAsmPrinter::doInitialization(Module &M) {
430   bool Result = AsmPrinter::doInitialization(M);
431 
432   if (!FileDirective.empty()) {
433     emitFileDirective(FileDirective);
434   }
435 
436   // Print out type strings for external functions here
437   for (Module::const_iterator I = M.begin(), E = M.end();
438        I != E; ++I) {
439     if (I->isDeclaration() && !I->isIntrinsic()) {
440       switch (I->getLinkage()) {
441       default:
442         assert(0 && "Unexpected linkage");
443       case Function::ExternalWeakLinkage:
444         ExtWeakSymbols.insert(I);
445         // fallthrough
446       case Function::ExternalLinkage:
447         break;
448       }
449     }
450   }
451 
452   // Emit initial debug information.
453   DW = getAnalysisIfAvailable<DwarfWriter>();
454   assert(DW && "Dwarf Writer is not available");
455   DW->BeginModule(&M, getAnalysisIfAvailable<MachineModuleInfo>(),
456                   O, this, TAI);
457   return Result;
458 }
459 
460 bool XCoreAsmPrinter::doFinalization(Module &M) {
461 
462   // Print out module-level global variables.
463   for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
464        I != E; ++I) {
465     emitGlobal(I);
466   }
467 
468   // Emit final debug information.
469   DW->EndModule();
470 
471   return AsmPrinter::doFinalization(M);
472 }
473