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