| //===- AsmWriterEmitter.cpp - Generate an assembly writer -----------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This tablegen backend is emits an assembly printer for the current target. |
| // Note that this is currently fairly skeletal, but will grow over time. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "AsmWriterEmitter.h" |
| #include "AsmWriterInst.h" |
| #include "CodeGenTarget.h" |
| #include "Record.h" |
| #include "StringToOffsetTable.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/Support/MathExtras.h" |
| #include <algorithm> |
| using namespace llvm; |
| |
| static void PrintCases(std::vector<std::pair<std::string, |
| AsmWriterOperand> > &OpsToPrint, raw_ostream &O) { |
| O << " case " << OpsToPrint.back().first << ": "; |
| AsmWriterOperand TheOp = OpsToPrint.back().second; |
| OpsToPrint.pop_back(); |
| |
| // Check to see if any other operands are identical in this list, and if so, |
| // emit a case label for them. |
| for (unsigned i = OpsToPrint.size(); i != 0; --i) |
| if (OpsToPrint[i-1].second == TheOp) { |
| O << "\n case " << OpsToPrint[i-1].first << ": "; |
| OpsToPrint.erase(OpsToPrint.begin()+i-1); |
| } |
| |
| // Finally, emit the code. |
| O << TheOp.getCode(); |
| O << "break;\n"; |
| } |
| |
| |
| /// EmitInstructions - Emit the last instruction in the vector and any other |
| /// instructions that are suitably similar to it. |
| static void EmitInstructions(std::vector<AsmWriterInst> &Insts, |
| raw_ostream &O) { |
| AsmWriterInst FirstInst = Insts.back(); |
| Insts.pop_back(); |
| |
| std::vector<AsmWriterInst> SimilarInsts; |
| unsigned DifferingOperand = ~0; |
| for (unsigned i = Insts.size(); i != 0; --i) { |
| unsigned DiffOp = Insts[i-1].MatchesAllButOneOp(FirstInst); |
| if (DiffOp != ~1U) { |
| if (DifferingOperand == ~0U) // First match! |
| DifferingOperand = DiffOp; |
| |
| // If this differs in the same operand as the rest of the instructions in |
| // this class, move it to the SimilarInsts list. |
| if (DifferingOperand == DiffOp || DiffOp == ~0U) { |
| SimilarInsts.push_back(Insts[i-1]); |
| Insts.erase(Insts.begin()+i-1); |
| } |
| } |
| } |
| |
| O << " case " << FirstInst.CGI->Namespace << "::" |
| << FirstInst.CGI->TheDef->getName() << ":\n"; |
| for (unsigned i = 0, e = SimilarInsts.size(); i != e; ++i) |
| O << " case " << SimilarInsts[i].CGI->Namespace << "::" |
| << SimilarInsts[i].CGI->TheDef->getName() << ":\n"; |
| for (unsigned i = 0, e = FirstInst.Operands.size(); i != e; ++i) { |
| if (i != DifferingOperand) { |
| // If the operand is the same for all instructions, just print it. |
| O << " " << FirstInst.Operands[i].getCode(); |
| } else { |
| // If this is the operand that varies between all of the instructions, |
| // emit a switch for just this operand now. |
| O << " switch (MI->getOpcode()) {\n"; |
| std::vector<std::pair<std::string, AsmWriterOperand> > OpsToPrint; |
| OpsToPrint.push_back(std::make_pair(FirstInst.CGI->Namespace + "::" + |
| FirstInst.CGI->TheDef->getName(), |
| FirstInst.Operands[i])); |
| |
| for (unsigned si = 0, e = SimilarInsts.size(); si != e; ++si) { |
| AsmWriterInst &AWI = SimilarInsts[si]; |
| OpsToPrint.push_back(std::make_pair(AWI.CGI->Namespace+"::"+ |
| AWI.CGI->TheDef->getName(), |
| AWI.Operands[i])); |
| } |
| std::reverse(OpsToPrint.begin(), OpsToPrint.end()); |
| while (!OpsToPrint.empty()) |
| PrintCases(OpsToPrint, O); |
| O << " }"; |
| } |
| O << "\n"; |
| } |
| O << " break;\n"; |
| } |
| |
| void AsmWriterEmitter:: |
| FindUniqueOperandCommands(std::vector<std::string> &UniqueOperandCommands, |
| std::vector<unsigned> &InstIdxs, |
| std::vector<unsigned> &InstOpsUsed) const { |
| InstIdxs.assign(NumberedInstructions.size(), ~0U); |
| |
| // This vector parallels UniqueOperandCommands, keeping track of which |
| // instructions each case are used for. It is a comma separated string of |
| // enums. |
| std::vector<std::string> InstrsForCase; |
| InstrsForCase.resize(UniqueOperandCommands.size()); |
| InstOpsUsed.assign(UniqueOperandCommands.size(), 0); |
| |
| for (unsigned i = 0, e = NumberedInstructions.size(); i != e; ++i) { |
| const AsmWriterInst *Inst = getAsmWriterInstByID(i); |
| if (Inst == 0) continue; // PHI, INLINEASM, DBG_LABEL, etc. |
| |
| std::string Command; |
| if (Inst->Operands.empty()) |
| continue; // Instruction already done. |
| |
| Command = " " + Inst->Operands[0].getCode() + "\n"; |
| |
| // Check to see if we already have 'Command' in UniqueOperandCommands. |
| // If not, add it. |
| bool FoundIt = false; |
| for (unsigned idx = 0, e = UniqueOperandCommands.size(); idx != e; ++idx) |
| if (UniqueOperandCommands[idx] == Command) { |
| InstIdxs[i] = idx; |
| InstrsForCase[idx] += ", "; |
| InstrsForCase[idx] += Inst->CGI->TheDef->getName(); |
| FoundIt = true; |
| break; |
| } |
| if (!FoundIt) { |
| InstIdxs[i] = UniqueOperandCommands.size(); |
| UniqueOperandCommands.push_back(Command); |
| InstrsForCase.push_back(Inst->CGI->TheDef->getName()); |
| |
| // This command matches one operand so far. |
| InstOpsUsed.push_back(1); |
| } |
| } |
| |
| // For each entry of UniqueOperandCommands, there is a set of instructions |
| // that uses it. If the next command of all instructions in the set are |
| // identical, fold it into the command. |
| for (unsigned CommandIdx = 0, e = UniqueOperandCommands.size(); |
| CommandIdx != e; ++CommandIdx) { |
| |
| for (unsigned Op = 1; ; ++Op) { |
| // Scan for the first instruction in the set. |
| std::vector<unsigned>::iterator NIT = |
| std::find(InstIdxs.begin(), InstIdxs.end(), CommandIdx); |
| if (NIT == InstIdxs.end()) break; // No commonality. |
| |
| // If this instruction has no more operands, we isn't anything to merge |
| // into this command. |
| const AsmWriterInst *FirstInst = |
| getAsmWriterInstByID(NIT-InstIdxs.begin()); |
| if (!FirstInst || FirstInst->Operands.size() == Op) |
| break; |
| |
| // Otherwise, scan to see if all of the other instructions in this command |
| // set share the operand. |
| bool AllSame = true; |
| // Keep track of the maximum, number of operands or any |
| // instruction we see in the group. |
| size_t MaxSize = FirstInst->Operands.size(); |
| |
| for (NIT = std::find(NIT+1, InstIdxs.end(), CommandIdx); |
| NIT != InstIdxs.end(); |
| NIT = std::find(NIT+1, InstIdxs.end(), CommandIdx)) { |
| // Okay, found another instruction in this command set. If the operand |
| // matches, we're ok, otherwise bail out. |
| const AsmWriterInst *OtherInst = |
| getAsmWriterInstByID(NIT-InstIdxs.begin()); |
| |
| if (OtherInst && |
| OtherInst->Operands.size() > FirstInst->Operands.size()) |
| MaxSize = std::max(MaxSize, OtherInst->Operands.size()); |
| |
| if (!OtherInst || OtherInst->Operands.size() == Op || |
| OtherInst->Operands[Op] != FirstInst->Operands[Op]) { |
| AllSame = false; |
| break; |
| } |
| } |
| if (!AllSame) break; |
| |
| // Okay, everything in this command set has the same next operand. Add it |
| // to UniqueOperandCommands and remember that it was consumed. |
| std::string Command = " " + FirstInst->Operands[Op].getCode() + "\n"; |
| |
| UniqueOperandCommands[CommandIdx] += Command; |
| InstOpsUsed[CommandIdx]++; |
| } |
| } |
| |
| // Prepend some of the instructions each case is used for onto the case val. |
| for (unsigned i = 0, e = InstrsForCase.size(); i != e; ++i) { |
| std::string Instrs = InstrsForCase[i]; |
| if (Instrs.size() > 70) { |
| Instrs.erase(Instrs.begin()+70, Instrs.end()); |
| Instrs += "..."; |
| } |
| |
| if (!Instrs.empty()) |
| UniqueOperandCommands[i] = " // " + Instrs + "\n" + |
| UniqueOperandCommands[i]; |
| } |
| } |
| |
| |
| static void UnescapeString(std::string &Str) { |
| for (unsigned i = 0; i != Str.size(); ++i) { |
| if (Str[i] == '\\' && i != Str.size()-1) { |
| switch (Str[i+1]) { |
| default: continue; // Don't execute the code after the switch. |
| case 'a': Str[i] = '\a'; break; |
| case 'b': Str[i] = '\b'; break; |
| case 'e': Str[i] = 27; break; |
| case 'f': Str[i] = '\f'; break; |
| case 'n': Str[i] = '\n'; break; |
| case 'r': Str[i] = '\r'; break; |
| case 't': Str[i] = '\t'; break; |
| case 'v': Str[i] = '\v'; break; |
| case '"': Str[i] = '\"'; break; |
| case '\'': Str[i] = '\''; break; |
| case '\\': Str[i] = '\\'; break; |
| } |
| // Nuke the second character. |
| Str.erase(Str.begin()+i+1); |
| } |
| } |
| } |
| |
| /// EmitPrintInstruction - Generate the code for the "printInstruction" method |
| /// implementation. |
| void AsmWriterEmitter::EmitPrintInstruction(raw_ostream &O) { |
| CodeGenTarget Target; |
| Record *AsmWriter = Target.getAsmWriter(); |
| std::string ClassName = AsmWriter->getValueAsString("AsmWriterClassName"); |
| |
| O << |
| "/// printInstruction - This method is automatically generated by tablegen\n" |
| "/// from the instruction set description.\n" |
| "void " << Target.getName() << ClassName |
| << "::printInstruction(const MachineInstr *MI) {\n"; |
| |
| std::vector<AsmWriterInst> Instructions; |
| |
| for (CodeGenTarget::inst_iterator I = Target.inst_begin(), |
| E = Target.inst_end(); I != E; ++I) |
| if (!I->second.AsmString.empty() && |
| I->second.TheDef->getName() != "PHI") |
| Instructions.push_back( |
| AsmWriterInst(I->second, |
| AsmWriter->getValueAsInt("Variant"), |
| AsmWriter->getValueAsInt("FirstOperandColumn"), |
| AsmWriter->getValueAsInt("OperandSpacing"))); |
| |
| // Get the instruction numbering. |
| NumberedInstructions = Target.getInstructionsByEnumValue(); |
| |
| // Compute the CodeGenInstruction -> AsmWriterInst mapping. Note that not |
| // all machine instructions are necessarily being printed, so there may be |
| // target instructions not in this map. |
| for (unsigned i = 0, e = Instructions.size(); i != e; ++i) |
| CGIAWIMap.insert(std::make_pair(Instructions[i].CGI, &Instructions[i])); |
| |
| // Build an aggregate string, and build a table of offsets into it. |
| StringToOffsetTable StringTable; |
| |
| /// OpcodeInfo - This encodes the index of the string to use for the first |
| /// chunk of the output as well as indices used for operand printing. |
| std::vector<unsigned> OpcodeInfo; |
| |
| unsigned MaxStringIdx = 0; |
| for (unsigned i = 0, e = NumberedInstructions.size(); i != e; ++i) { |
| AsmWriterInst *AWI = CGIAWIMap[NumberedInstructions[i]]; |
| unsigned Idx; |
| if (AWI == 0) { |
| // Something not handled by the asmwriter printer. |
| Idx = ~0U; |
| } else if (AWI->Operands[0].OperandType != |
| AsmWriterOperand::isLiteralTextOperand || |
| AWI->Operands[0].Str.empty()) { |
| // Something handled by the asmwriter printer, but with no leading string. |
| Idx = StringTable.GetOrAddStringOffset(""); |
| } else { |
| std::string Str = AWI->Operands[0].Str; |
| UnescapeString(Str); |
| Idx = StringTable.GetOrAddStringOffset(Str); |
| MaxStringIdx = std::max(MaxStringIdx, Idx); |
| |
| // Nuke the string from the operand list. It is now handled! |
| AWI->Operands.erase(AWI->Operands.begin()); |
| } |
| |
| // Bias offset by one since we want 0 as a sentinel. |
| OpcodeInfo.push_back(Idx+1); |
| } |
| |
| // Figure out how many bits we used for the string index. |
| unsigned AsmStrBits = Log2_32_Ceil(MaxStringIdx+2); |
| |
| // To reduce code size, we compactify common instructions into a few bits |
| // in the opcode-indexed table. |
| unsigned BitsLeft = 32-AsmStrBits; |
| |
| std::vector<std::vector<std::string> > TableDrivenOperandPrinters; |
| |
| while (1) { |
| std::vector<std::string> UniqueOperandCommands; |
| std::vector<unsigned> InstIdxs; |
| std::vector<unsigned> NumInstOpsHandled; |
| FindUniqueOperandCommands(UniqueOperandCommands, InstIdxs, |
| NumInstOpsHandled); |
| |
| // If we ran out of operands to print, we're done. |
| if (UniqueOperandCommands.empty()) break; |
| |
| // Compute the number of bits we need to represent these cases, this is |
| // ceil(log2(numentries)). |
| unsigned NumBits = Log2_32_Ceil(UniqueOperandCommands.size()); |
| |
| // If we don't have enough bits for this operand, don't include it. |
| if (NumBits > BitsLeft) { |
| DEBUG(errs() << "Not enough bits to densely encode " << NumBits |
| << " more bits\n"); |
| break; |
| } |
| |
| // Otherwise, we can include this in the initial lookup table. Add it in. |
| BitsLeft -= NumBits; |
| for (unsigned i = 0, e = InstIdxs.size(); i != e; ++i) |
| if (InstIdxs[i] != ~0U) |
| OpcodeInfo[i] |= InstIdxs[i] << (BitsLeft+AsmStrBits); |
| |
| // Remove the info about this operand. |
| for (unsigned i = 0, e = NumberedInstructions.size(); i != e; ++i) { |
| if (AsmWriterInst *Inst = getAsmWriterInstByID(i)) |
| if (!Inst->Operands.empty()) { |
| unsigned NumOps = NumInstOpsHandled[InstIdxs[i]]; |
| assert(NumOps <= Inst->Operands.size() && |
| "Can't remove this many ops!"); |
| Inst->Operands.erase(Inst->Operands.begin(), |
| Inst->Operands.begin()+NumOps); |
| } |
| } |
| |
| // Remember the handlers for this set of operands. |
| TableDrivenOperandPrinters.push_back(UniqueOperandCommands); |
| } |
| |
| |
| |
| O<<" static const unsigned OpInfo[] = {\n"; |
| for (unsigned i = 0, e = NumberedInstructions.size(); i != e; ++i) { |
| O << " " << OpcodeInfo[i] << "U,\t// " |
| << NumberedInstructions[i]->TheDef->getName() << "\n"; |
| } |
| // Add a dummy entry so the array init doesn't end with a comma. |
| O << " 0U\n"; |
| O << " };\n\n"; |
| |
| // Emit the string itself. |
| O << " const char *AsmStrs = \n"; |
| StringTable.EmitString(O); |
| O << ";\n\n"; |
| |
| O << " O << \"\\t\";\n\n"; |
| |
| O << " // Emit the opcode for the instruction.\n" |
| << " unsigned Bits = OpInfo[MI->getOpcode()];\n" |
| << " assert(Bits != 0 && \"Cannot print this instruction.\");\n" |
| << " O << AsmStrs+(Bits & " << (1 << AsmStrBits)-1 << ")-1;\n\n"; |
| |
| // Output the table driven operand information. |
| BitsLeft = 32-AsmStrBits; |
| for (unsigned i = 0, e = TableDrivenOperandPrinters.size(); i != e; ++i) { |
| std::vector<std::string> &Commands = TableDrivenOperandPrinters[i]; |
| |
| // Compute the number of bits we need to represent these cases, this is |
| // ceil(log2(numentries)). |
| unsigned NumBits = Log2_32_Ceil(Commands.size()); |
| assert(NumBits <= BitsLeft && "consistency error"); |
| |
| // Emit code to extract this field from Bits. |
| BitsLeft -= NumBits; |
| |
| O << "\n // Fragment " << i << " encoded into " << NumBits |
| << " bits for " << Commands.size() << " unique commands.\n"; |
| |
| if (Commands.size() == 2) { |
| // Emit two possibilitys with if/else. |
| O << " if ((Bits >> " << (BitsLeft+AsmStrBits) << ") & " |
| << ((1 << NumBits)-1) << ") {\n" |
| << Commands[1] |
| << " } else {\n" |
| << Commands[0] |
| << " }\n\n"; |
| } else { |
| O << " switch ((Bits >> " << (BitsLeft+AsmStrBits) << ") & " |
| << ((1 << NumBits)-1) << ") {\n" |
| << " default: // unreachable.\n"; |
| |
| // Print out all the cases. |
| for (unsigned i = 0, e = Commands.size(); i != e; ++i) { |
| O << " case " << i << ":\n"; |
| O << Commands[i]; |
| O << " break;\n"; |
| } |
| O << " }\n\n"; |
| } |
| } |
| |
| // Okay, delete instructions with no operand info left. |
| for (unsigned i = 0, e = Instructions.size(); i != e; ++i) { |
| // Entire instruction has been emitted? |
| AsmWriterInst &Inst = Instructions[i]; |
| if (Inst.Operands.empty()) { |
| Instructions.erase(Instructions.begin()+i); |
| --i; --e; |
| } |
| } |
| |
| |
| // Because this is a vector, we want to emit from the end. Reverse all of the |
| // elements in the vector. |
| std::reverse(Instructions.begin(), Instructions.end()); |
| |
| |
| // Now that we've emitted all of the operand info that fit into 32 bits, emit |
| // information for those instructions that are left. This is a less dense |
| // encoding, but we expect the main 32-bit table to handle the majority of |
| // instructions. |
| if (!Instructions.empty()) { |
| // Find the opcode # of inline asm. |
| O << " switch (MI->getOpcode()) {\n"; |
| while (!Instructions.empty()) |
| EmitInstructions(Instructions, O); |
| |
| O << " }\n"; |
| O << " return;\n"; |
| } |
| |
| O << "}\n"; |
| } |
| |
| |
| void AsmWriterEmitter::EmitGetRegisterName(raw_ostream &O) { |
| CodeGenTarget Target; |
| Record *AsmWriter = Target.getAsmWriter(); |
| std::string ClassName = AsmWriter->getValueAsString("AsmWriterClassName"); |
| const std::vector<CodeGenRegister> &Registers = Target.getRegisters(); |
| |
| StringToOffsetTable StringTable; |
| O << |
| "\n\n/// getRegisterName - This method is automatically generated by tblgen\n" |
| "/// from the register set description. This returns the assembler name\n" |
| "/// for the specified register.\n" |
| "const char *" << Target.getName() << ClassName |
| << "::getRegisterName(unsigned RegNo) {\n" |
| << " assert(RegNo && RegNo < " << (Registers.size()+1) |
| << " && \"Invalid register number!\");\n" |
| << "\n" |
| << " static const unsigned RegAsmOffset[] = {"; |
| for (unsigned i = 0, e = Registers.size(); i != e; ++i) { |
| const CodeGenRegister &Reg = Registers[i]; |
| |
| std::string AsmName = Reg.TheDef->getValueAsString("AsmName"); |
| if (AsmName.empty()) |
| AsmName = Reg.getName(); |
| |
| |
| if ((i % 14) == 0) |
| O << "\n "; |
| |
| O << StringTable.GetOrAddStringOffset(AsmName) << ", "; |
| } |
| O << "0\n" |
| << " };\n" |
| << "\n"; |
| |
| O << " const char *AsmStrs =\n"; |
| StringTable.EmitString(O); |
| O << ";\n"; |
| |
| O << " return AsmStrs+RegAsmOffset[RegNo-1];\n" |
| << "}\n"; |
| } |
| |
| void AsmWriterEmitter::EmitGetInstructionName(raw_ostream &O) { |
| CodeGenTarget Target; |
| Record *AsmWriter = Target.getAsmWriter(); |
| std::string ClassName = AsmWriter->getValueAsString("AsmWriterClassName"); |
| |
| const std::vector<const CodeGenInstruction*> &NumberedInstructions = |
| Target.getInstructionsByEnumValue(); |
| |
| StringToOffsetTable StringTable; |
| O << |
| "\n\n#ifdef GET_INSTRUCTION_NAME\n" |
| "#undef GET_INSTRUCTION_NAME\n\n" |
| "/// getInstructionName: This method is automatically generated by tblgen\n" |
| "/// from the instruction set description. This returns the enum name of the\n" |
| "/// specified instruction.\n" |
| "const char *" << Target.getName() << ClassName |
| << "::getInstructionName(unsigned Opcode) {\n" |
| << " assert(Opcode < " << NumberedInstructions.size() |
| << " && \"Invalid instruction number!\");\n" |
| << "\n" |
| << " static const unsigned InstAsmOffset[] = {"; |
| for (unsigned i = 0, e = NumberedInstructions.size(); i != e; ++i) { |
| const CodeGenInstruction &Inst = *NumberedInstructions[i]; |
| |
| std::string AsmName = Inst.TheDef->getName(); |
| if ((i % 14) == 0) |
| O << "\n "; |
| |
| O << StringTable.GetOrAddStringOffset(AsmName) << ", "; |
| } |
| O << "0\n" |
| << " };\n" |
| << "\n"; |
| |
| O << " const char *Strs =\n"; |
| StringTable.EmitString(O); |
| O << ";\n"; |
| |
| O << " return Strs+InstAsmOffset[Opcode];\n" |
| << "}\n\n#endif\n"; |
| } |
| |
| |
| |
| void AsmWriterEmitter::run(raw_ostream &O) { |
| EmitSourceFileHeader("Assembly Writer Source Fragment", O); |
| |
| EmitPrintInstruction(O); |
| EmitGetRegisterName(O); |
| EmitGetInstructionName(O); |
| } |
| |