1 //===-- MBlazeAsmPrinter.cpp - MBlaze LLVM assembly writer ----------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains a printer that converts from our internal representation
11 // of machine-dependent LLVM code to GAS-format MBlaze assembly language.
13 //===----------------------------------------------------------------------===//
15 #define DEBUG_TYPE "mblaze-asm-printer"
18 #include "MBlazeSubtarget.h"
19 #include "MBlazeInstrInfo.h"
20 #include "MBlazeTargetMachine.h"
21 #include "MBlazeMachineFunction.h"
22 #include "MBlazeMCInstLower.h"
23 #include "InstPrinter/MBlazeInstPrinter.h"
24 #include "llvm/Constants.h"
25 #include "llvm/DerivedTypes.h"
26 #include "llvm/Module.h"
27 #include "llvm/CodeGen/AsmPrinter.h"
28 #include "llvm/CodeGen/MachineFunctionPass.h"
29 #include "llvm/CodeGen/MachineConstantPool.h"
30 #include "llvm/CodeGen/MachineFrameInfo.h"
31 #include "llvm/CodeGen/MachineInstr.h"
32 #include "llvm/MC/MCInst.h"
33 #include "llvm/MC/MCStreamer.h"
34 #include "llvm/MC/MCAsmInfo.h"
35 #include "llvm/MC/MCSymbol.h"
36 #include "llvm/Target/Mangler.h"
37 #include "llvm/Target/TargetData.h"
38 #include "llvm/Target/TargetLoweringObjectFile.h"
39 #include "llvm/Target/TargetMachine.h"
40 #include "llvm/Target/TargetOptions.h"
41 #include "llvm/Target/TargetRegistry.h"
42 #include "llvm/ADT/SmallString.h"
43 #include "llvm/ADT/StringExtras.h"
44 #include "llvm/Support/ErrorHandling.h"
45 #include "llvm/Support/raw_ostream.h"
51 class MBlazeAsmPrinter : public AsmPrinter {
52 const MBlazeSubtarget *Subtarget;
54 explicit MBlazeAsmPrinter(TargetMachine &TM, MCStreamer &Streamer)
55 : AsmPrinter(TM, Streamer) {
56 Subtarget = &TM.getSubtarget<MBlazeSubtarget>();
59 virtual const char *getPassName() const {
60 return "MBlaze Assembly Printer";
63 void printSavedRegsBitmask();
64 void emitFrameDirective();
65 virtual void EmitFunctionBodyStart();
66 virtual void EmitFunctionBodyEnd();
67 virtual void EmitFunctionEntryLabel();
69 virtual bool isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB)
72 bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
73 unsigned AsmVariant, const char *ExtraCode,
75 void printOperand(const MachineInstr *MI, int opNum, raw_ostream &O);
76 void printUnsignedImm(const MachineInstr *MI, int opNum, raw_ostream &O);
77 void printFSLImm(const MachineInstr *MI, int opNum, raw_ostream &O);
78 void printMemOperand(const MachineInstr *MI, int opNum, raw_ostream &O,
79 const char *Modifier = 0);
81 void EmitInstruction(const MachineInstr *MI);
83 } // end of anonymous namespace
85 // #include "MBlazeGenAsmWriter.inc"
87 //===----------------------------------------------------------------------===//
89 // MBlaze Asm Directives
91 // -- Frame directive "frame Stackpointer, Stacksize, RARegister"
92 // Describe the stack frame.
94 // -- Mask directives "mask bitmask, offset"
95 // Tells the assembler which registers are saved and where.
96 // bitmask - contain a little endian bitset indicating which registers are
97 // saved on function prologue (e.g. with a 0x80000000 mask, the
98 // assembler knows the register 31 (RA) is saved at prologue.
99 // offset - the position before stack pointer subtraction indicating where
100 // the first saved register on prologue is located. (e.g. with a
102 // Consider the following function prologue:
105 // .mask 0xc0000000,-8
110 // With a 0xc0000000 mask, the assembler knows the register 15 (R15) and
111 // 19 (R19) are saved at prologue. As the save order on prologue is from
112 // left to right, R15 is saved first. A -8 offset means that after the
113 // stack pointer subtration, the first register in the mask (R15) will be
114 // saved at address 48-8=40.
116 //===----------------------------------------------------------------------===//
118 // Print a 32 bit hex number with all numbers.
119 static void printHex32(unsigned int Value, raw_ostream &O) {
121 for (int i = 7; i >= 0; i--)
122 O << utohexstr((Value & (0xF << (i*4))) >> (i*4));
125 // Create a bitmask with all callee saved registers for CPU or Floating Point
126 // registers. For CPU registers consider RA, GP and FP for saving if necessary.
127 void MBlazeAsmPrinter::printSavedRegsBitmask() {
128 const TargetFrameInfo *TFI = TM.getFrameInfo();
129 const TargetRegisterInfo &RI = *TM.getRegisterInfo();
131 // CPU Saved Registers Bitmasks
132 unsigned int CPUBitmask = 0;
134 // Set the CPU Bitmasks
135 const MachineFrameInfo *MFI = MF->getFrameInfo();
136 const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
137 for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
138 unsigned Reg = CSI[i].getReg();
139 unsigned RegNum = MBlazeRegisterInfo::getRegisterNumbering(Reg);
140 if (MBlaze::GPRRegisterClass->contains(Reg))
141 CPUBitmask |= (1 << RegNum);
144 // Return Address and Frame registers must also be set in CPUBitmask.
146 CPUBitmask |= (1 << MBlazeRegisterInfo::
147 getRegisterNumbering(RI.getFrameRegister(*MF)));
149 if (MFI->adjustsStack())
150 CPUBitmask |= (1 << MBlazeRegisterInfo::
151 getRegisterNumbering(RI.getRARegister()));
154 OutStreamer.EmitRawText("\t.mask\t0x" + Twine::utohexstr(CPUBitmask));
158 void MBlazeAsmPrinter::emitFrameDirective() {
159 if (!OutStreamer.hasRawTextSupport())
162 const TargetRegisterInfo &RI = *TM.getRegisterInfo();
163 unsigned stkReg = RI.getFrameRegister(*MF);
164 unsigned retReg = RI.getRARegister();
165 unsigned stkSze = MF->getFrameInfo()->getStackSize();
166 if (stkSze < 28 && MF->getFrameInfo()->adjustsStack()) stkSze = 28;
168 OutStreamer.EmitRawText("\t.frame\t" +
169 Twine(MBlazeInstPrinter::getRegisterName(stkReg)) +
170 "," + Twine(stkSze) + "," +
171 Twine(MBlazeInstPrinter::getRegisterName(retReg)));
174 void MBlazeAsmPrinter::EmitFunctionEntryLabel() {
175 if (OutStreamer.hasRawTextSupport())
176 OutStreamer.EmitRawText("\t.ent\t" + Twine(CurrentFnSym->getName()));
177 AsmPrinter::EmitFunctionEntryLabel();
180 void MBlazeAsmPrinter::EmitFunctionBodyStart() {
181 if (!OutStreamer.hasRawTextSupport())
184 emitFrameDirective();
185 printSavedRegsBitmask();
187 // SmallString<128> Str;
188 // raw_svector_ostream OS(Str);
189 // printSavedRegsBitmask(OS);
190 // OutStreamer.EmitRawText(OS.str());
193 void MBlazeAsmPrinter::EmitFunctionBodyEnd() {
194 if (OutStreamer.hasRawTextSupport())
195 OutStreamer.EmitRawText("\t.end\t" + Twine(CurrentFnSym->getName()));
198 //===----------------------------------------------------------------------===//
199 void MBlazeAsmPrinter::EmitInstruction(const MachineInstr *MI) {
200 MBlazeMCInstLower MCInstLowering(OutContext, *Mang, *this);
203 MCInstLowering.Lower(MI, TmpInst);
204 OutStreamer.EmitInstruction(TmpInst);
207 // Print out an operand for an inline asm expression.
208 bool MBlazeAsmPrinter::
209 PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
210 unsigned AsmVariant,const char *ExtraCode, raw_ostream &O) {
211 // Does this asm operand have a single letter operand modifier?
212 if (ExtraCode && ExtraCode[0])
213 return true; // Unknown modifier.
215 printOperand(MI, OpNo, O);
219 void MBlazeAsmPrinter::printOperand(const MachineInstr *MI, int opNum,
221 const MachineOperand &MO = MI->getOperand(opNum);
223 switch (MO.getType()) {
224 case MachineOperand::MO_Register:
225 O << MBlazeInstPrinter::getRegisterName(MO.getReg());
228 case MachineOperand::MO_Immediate:
229 O << (int32_t)MO.getImm();
232 case MachineOperand::MO_FPImmediate: {
233 const ConstantFP *fp = MO.getFPImm();
234 printHex32(fp->getValueAPF().bitcastToAPInt().getZExtValue(), O);
235 O << ";\t# immediate = " << *fp;
239 case MachineOperand::MO_MachineBasicBlock:
240 O << *MO.getMBB()->getSymbol();
243 case MachineOperand::MO_GlobalAddress:
244 O << *Mang->getSymbol(MO.getGlobal());
247 case MachineOperand::MO_ExternalSymbol:
248 O << *GetExternalSymbolSymbol(MO.getSymbolName());
251 case MachineOperand::MO_JumpTableIndex:
252 O << MAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber()
253 << '_' << MO.getIndex();
256 case MachineOperand::MO_ConstantPoolIndex:
257 O << MAI->getPrivateGlobalPrefix() << "CPI"
258 << getFunctionNumber() << "_" << MO.getIndex();
260 O << "+" << MO.getOffset();
264 llvm_unreachable("<unknown operand type>");
268 void MBlazeAsmPrinter::printUnsignedImm(const MachineInstr *MI, int opNum,
270 const MachineOperand &MO = MI->getOperand(opNum);
272 O << (uint32_t)MO.getImm();
274 printOperand(MI, opNum, O);
277 void MBlazeAsmPrinter::printFSLImm(const MachineInstr *MI, int opNum,
279 const MachineOperand &MO = MI->getOperand(opNum);
281 O << "rfsl" << (unsigned int)MO.getImm();
283 printOperand(MI, opNum, O);
286 void MBlazeAsmPrinter::
287 printMemOperand(const MachineInstr *MI, int opNum, raw_ostream &O,
288 const char *Modifier) {
289 printOperand(MI, opNum, O);
291 printOperand(MI, opNum+1, O);
294 /// isBlockOnlyReachableByFallthough - Return true if the basic block has
295 /// exactly one predecessor and the control transfer mechanism between
296 /// the predecessor and this block is a fall-through.
297 bool MBlazeAsmPrinter::
298 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
299 // If this is a landing pad, it isn't a fall through. If it has no preds,
300 // then nothing falls through to it.
301 if (MBB->isLandingPad() || MBB->pred_empty())
304 // If there isn't exactly one predecessor, it can't be a fall through.
305 MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI;
307 if (PI2 != MBB->pred_end())
310 // The predecessor has to be immediately before this block.
311 const MachineBasicBlock *Pred = *PI;
313 if (!Pred->isLayoutSuccessor(MBB))
316 // If the block is completely empty, then it definitely does fall through.
320 // Check if the last terminator is an unconditional branch.
321 MachineBasicBlock::const_iterator I = Pred->end();
322 while (I != Pred->begin() && !(--I)->getDesc().isTerminator())
324 return I == Pred->end() || !I->getDesc().isBarrier();
327 static MCInstPrinter *createMBlazeMCInstPrinter(const Target &T,
328 unsigned SyntaxVariant,
329 const MCAsmInfo &MAI) {
330 if (SyntaxVariant == 0)
331 return new MBlazeInstPrinter(MAI);
335 // Force static initialization.
336 extern "C" void LLVMInitializeMBlazeAsmPrinter() {
337 RegisterAsmPrinter<MBlazeAsmPrinter> X(TheMBlazeTarget);
338 TargetRegistry::RegisterMCInstPrinter(TheMBlazeTarget,
339 createMBlazeMCInstPrinter);