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llvm-mirror/utils/TableGen/AsmWriterEmitter.cpp
Benjamin Kramer 87d13166c7 Make llvm::StringRef to std::string conversions explicit. 
This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.

This doesn't actually modify StringRef yet, I'll do that in a follow-up.
2020-01-28 23:25:25 +01:00

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//===- AsmWriterEmitter.cpp - Generate an assembly writer -----------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This tablegen backend emits an assembly printer for the current target.
// Note that this is currently fairly skeletal, but will grow over time.
//
//===----------------------------------------------------------------------===//
#include "AsmWriterInst.h"
#include "CodeGenInstruction.h"
#include "CodeGenRegisters.h"
#include "CodeGenTarget.h"
#include "SequenceToOffsetTable.h"
#include "Types.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/TableGen/Error.h"
#include "llvm/TableGen/Record.h"
#include "llvm/TableGen/TableGenBackend.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <deque>
#include <iterator>
#include <map>
#include <set>
#include <string>
#include <tuple>
#include <utility>
#include <vector>
using namespace llvm;
#define DEBUG_TYPE "asm-writer-emitter"
namespace {
class AsmWriterEmitter {
RecordKeeper &Records;
CodeGenTarget Target;
ArrayRef<const CodeGenInstruction *> NumberedInstructions;
std::vector<AsmWriterInst> Instructions;
public:
AsmWriterEmitter(RecordKeeper &R);
void run(raw_ostream &o);
private:
void EmitPrintInstruction(raw_ostream &o);
void EmitGetRegisterName(raw_ostream &o);
void EmitPrintAliasInstruction(raw_ostream &O);
void FindUniqueOperandCommands(std::vector<std::string> &UOC,
std::vector<std::vector<unsigned>> &InstIdxs,
std::vector<unsigned> &InstOpsUsed,
bool PassSubtarget) const;
};
} // end anonymous namespace
static void PrintCases(std::vector<std::pair<std::string,
AsmWriterOperand>> &OpsToPrint, raw_ostream &O,
bool PassSubtarget) {
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 << "\n " << TheOp.getCode(PassSubtarget);
O << "\n 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, bool PassSubtarget) {
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 (const AsmWriterInst &AWI : SimilarInsts)
O << " case " << AWI.CGI->Namespace << "::"
<< AWI.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(PassSubtarget);
} 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";
O << " default: llvm_unreachable(\"Unexpected opcode.\");\n";
std::vector<std::pair<std::string, AsmWriterOperand>> OpsToPrint;
OpsToPrint.push_back(std::make_pair(FirstInst.CGI->Namespace.str() + "::" +
FirstInst.CGI->TheDef->getName().str(),
FirstInst.Operands[i]));
for (const AsmWriterInst &AWI : SimilarInsts) {
OpsToPrint.push_back(std::make_pair(AWI.CGI->Namespace.str()+"::" +
AWI.CGI->TheDef->getName().str(),
AWI.Operands[i]));
}
std::reverse(OpsToPrint.begin(), OpsToPrint.end());
while (!OpsToPrint.empty())
PrintCases(OpsToPrint, O, PassSubtarget);
O << " }";
}
O << "\n";
}
O << " break;\n";
}
void AsmWriterEmitter::
FindUniqueOperandCommands(std::vector<std::string> &UniqueOperandCommands,
std::vector<std::vector<unsigned>> &InstIdxs,
std::vector<unsigned> &InstOpsUsed,
bool PassSubtarget) const {
// 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 (size_t i = 0, e = Instructions.size(); i != e; ++i) {
const AsmWriterInst &Inst = Instructions[i];
if (Inst.Operands.empty())
continue; // Instruction already done.
std::string Command = " "+Inst.Operands[0].getCode(PassSubtarget)+"\n";
// Check to see if we already have 'Command' in UniqueOperandCommands.
// If not, add it.
auto I = llvm::find(UniqueOperandCommands, Command);
if (I != UniqueOperandCommands.end()) {
size_t idx = I - UniqueOperandCommands.begin();
InstrsForCase[idx] += ", ";
InstrsForCase[idx] += Inst.CGI->TheDef->getName();
InstIdxs[idx].push_back(i);
} else {
UniqueOperandCommands.push_back(std::move(Command));
InstrsForCase.push_back(std::string(Inst.CGI->TheDef->getName()));
InstIdxs.emplace_back();
InstIdxs.back().push_back(i);
// 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 (size_t CommandIdx = 0, e = UniqueOperandCommands.size();
CommandIdx != e; ++CommandIdx) {
const auto &Idxs = InstIdxs[CommandIdx];
for (unsigned Op = 1; ; ++Op) {
// Find the first instruction in the set.
const AsmWriterInst &FirstInst = Instructions[Idxs.front()];
// If this instruction has no more operands, we isn't anything to merge
// into this command.
if (FirstInst.Operands.size() == Op)
break;
// Otherwise, scan to see if all of the other instructions in this command
// set share the operand.
if (std::any_of(Idxs.begin()+1, Idxs.end(),
[&](unsigned Idx) {
const AsmWriterInst &OtherInst = Instructions[Idx];
return OtherInst.Operands.size() == Op ||
OtherInst.Operands[Op] != FirstInst.Operands[Op];
}))
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(PassSubtarget) + "\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. Destroys all instances of AsmWriterInst information, by
/// clearing the Instructions vector.
void AsmWriterEmitter::EmitPrintInstruction(raw_ostream &O) {
Record *AsmWriter = Target.getAsmWriter();
StringRef ClassName = AsmWriter->getValueAsString("AsmWriterClassName");
bool PassSubtarget = AsmWriter->getValueAsInt("PassSubtarget");
O << "/// printInstruction - This method is automatically generated by "
"tablegen\n"
"/// from the instruction set description.\n"
"void "
<< Target.getName() << ClassName
<< "::printInstruction(const MCInst *MI, uint64_t Address, "
<< (PassSubtarget ? "const MCSubtargetInfo &STI, " : "")
<< "raw_ostream &O) {\n";
// Build an aggregate string, and build a table of offsets into it.
SequenceToOffsetTable<std::string> 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<uint64_t> OpcodeInfo(NumberedInstructions.size());
const unsigned OpcodeInfoBits = 64;
// Add all strings to the string table upfront so it can generate an optimized
// representation.
for (AsmWriterInst &AWI : Instructions) {
if (AWI.Operands[0].OperandType ==
AsmWriterOperand::isLiteralTextOperand &&
!AWI.Operands[0].Str.empty()) {
std::string Str = AWI.Operands[0].Str;
UnescapeString(Str);
StringTable.add(Str);
}
}
StringTable.layout();
unsigned MaxStringIdx = 0;
for (AsmWriterInst &AWI : Instructions) {
unsigned Idx;
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.get("");
} else {
std::string Str = AWI.Operands[0].Str;
UnescapeString(Str);
Idx = StringTable.get(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[AWI.CGIIndex] = 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 = OpcodeInfoBits-AsmStrBits;
std::vector<std::vector<std::string>> TableDrivenOperandPrinters;
while (true) {
std::vector<std::string> UniqueOperandCommands;
std::vector<std::vector<unsigned>> InstIdxs;
std::vector<unsigned> NumInstOpsHandled;
FindUniqueOperandCommands(UniqueOperandCommands, InstIdxs,
NumInstOpsHandled, PassSubtarget);
// 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) {
LLVM_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.
for (size_t i = 0, e = InstIdxs.size(); i != e; ++i) {
unsigned NumOps = NumInstOpsHandled[i];
for (unsigned Idx : InstIdxs[i]) {
OpcodeInfo[Instructions[Idx].CGIIndex] |=
(uint64_t)i << (OpcodeInfoBits-BitsLeft);
// Remove the info about this operand from the instruction.
AsmWriterInst &Inst = Instructions[Idx];
if (!Inst.Operands.empty()) {
assert(NumOps <= Inst.Operands.size() &&
"Can't remove this many ops!");
Inst.Operands.erase(Inst.Operands.begin(),
Inst.Operands.begin()+NumOps);
}
}
}
BitsLeft -= NumBits;
// Remember the handlers for this set of operands.
TableDrivenOperandPrinters.push_back(std::move(UniqueOperandCommands));
}
// Emit the string table itself.
StringTable.emitStringLiteralDef(O, " static const char AsmStrs[]");
// Emit the lookup tables in pieces to minimize wasted bytes.
unsigned BytesNeeded = ((OpcodeInfoBits - BitsLeft) + 7) / 8;
unsigned Table = 0, Shift = 0;
SmallString<128> BitsString;
raw_svector_ostream BitsOS(BitsString);
// If the total bits is more than 32-bits we need to use a 64-bit type.
BitsOS << " uint" << ((BitsLeft < (OpcodeInfoBits - 32)) ? 64 : 32)
<< "_t Bits = 0;\n";
while (BytesNeeded != 0) {
// Figure out how big this table section needs to be, but no bigger than 4.
unsigned TableSize = std::min(1 << Log2_32(BytesNeeded), 4);
BytesNeeded -= TableSize;
TableSize *= 8; // Convert to bits;
uint64_t Mask = (1ULL << TableSize) - 1;
O << " static const uint" << TableSize << "_t OpInfo" << Table
<< "[] = {\n";
for (unsigned i = 0, e = NumberedInstructions.size(); i != e; ++i) {
O << " " << ((OpcodeInfo[i] >> Shift) & Mask) << "U,\t// "
<< NumberedInstructions[i]->TheDef->getName() << "\n";
}
O << " };\n\n";
// Emit string to combine the individual table lookups.
BitsOS << " Bits |= ";
// If the total bits is more than 32-bits we need to use a 64-bit type.
if (BitsLeft < (OpcodeInfoBits - 32))
BitsOS << "(uint64_t)";
BitsOS << "OpInfo" << Table << "[MI->getOpcode()] << " << Shift << ";\n";
// Prepare the shift for the next iteration and increment the table count.
Shift += TableSize;
++Table;
}
// Emit the initial tab character.
O << " O << \"\\t\";\n\n";
O << " // Emit the opcode for the instruction.\n";
O << BitsString;
// Emit the starting string.
O << " assert(Bits != 0 && \"Cannot print this instruction.\");\n"
<< " O << AsmStrs+(Bits & " << (1 << AsmStrBits)-1 << ")-1;\n\n";
// Output the table driven operand information.
BitsLeft = OpcodeInfoBits-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.
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 >> "
<< (OpcodeInfoBits-BitsLeft) << ") & "
<< ((1 << NumBits)-1) << ") {\n"
<< Commands[1]
<< " } else {\n"
<< Commands[0]
<< " }\n\n";
} else if (Commands.size() == 1) {
// Emit a single possibility.
O << Commands[0] << "\n\n";
} else {
O << " switch ((Bits >> "
<< (OpcodeInfoBits-BitsLeft) << ") & "
<< ((1 << NumBits)-1) << ") {\n"
<< " default: llvm_unreachable(\"Invalid command number.\");\n";
// Print out all the cases.
for (unsigned j = 0, e = Commands.size(); j != e; ++j) {
O << " case " << j << ":\n";
O << Commands[j];
O << " break;\n";
}
O << " }\n\n";
}
BitsLeft -= NumBits;
}
// Okay, delete instructions with no operand info left.
auto I = llvm::remove_if(Instructions,
[](AsmWriterInst &Inst) { return Inst.Operands.empty(); });
Instructions.erase(I, Instructions.end());
// 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 64 bits, emit
// information for those instructions that are left. This is a less dense
// encoding, but we expect the main 64-bit table to handle the majority of
// instructions.
if (!Instructions.empty()) {
// Find the opcode # of inline asm.
O << " switch (MI->getOpcode()) {\n";
O << " default: llvm_unreachable(\"Unexpected opcode.\");\n";
while (!Instructions.empty())
EmitInstructions(Instructions, O, PassSubtarget);
O << " }\n";
}
O << "}\n";
}
static void
emitRegisterNameString(raw_ostream &O, StringRef AltName,
const std::deque<CodeGenRegister> &Registers) {
SequenceToOffsetTable<std::string> StringTable;
SmallVector<std::string, 4> AsmNames(Registers.size());
unsigned i = 0;
for (const auto &Reg : Registers) {
std::string &AsmName = AsmNames[i++];
// "NoRegAltName" is special. We don't need to do a lookup for that,
// as it's just a reference to the default register name.
if (AltName == "" || AltName == "NoRegAltName") {
AsmName = std::string(Reg.TheDef->getValueAsString("AsmName"));
if (AsmName.empty())
AsmName = std::string(Reg.getName());
} else {
// Make sure the register has an alternate name for this index.
std::vector<Record*> AltNameList =
Reg.TheDef->getValueAsListOfDefs("RegAltNameIndices");
unsigned Idx = 0, e;
for (e = AltNameList.size();
Idx < e && (AltNameList[Idx]->getName() != AltName);
++Idx)
;
// If the register has an alternate name for this index, use it.
// Otherwise, leave it empty as an error flag.
if (Idx < e) {
std::vector<StringRef> AltNames =
Reg.TheDef->getValueAsListOfStrings("AltNames");
if (AltNames.size() <= Idx)
PrintFatalError(Reg.TheDef->getLoc(),
"Register definition missing alt name for '" +
AltName + "'.");
AsmName = std::string(AltNames[Idx]);
}
}
StringTable.add(AsmName);
}
StringTable.layout();
StringTable.emitStringLiteralDef(O, Twine(" static const char AsmStrs") +
AltName + "[]");
O << " static const " << getMinimalTypeForRange(StringTable.size() - 1, 32)
<< " RegAsmOffset" << AltName << "[] = {";
for (unsigned i = 0, e = Registers.size(); i != e; ++i) {
if ((i % 14) == 0)
O << "\n ";
O << StringTable.get(AsmNames[i]) << ", ";
}
O << "\n };\n"
<< "\n";
}
void AsmWriterEmitter::EmitGetRegisterName(raw_ostream &O) {
Record *AsmWriter = Target.getAsmWriter();
StringRef ClassName = AsmWriter->getValueAsString("AsmWriterClassName");
const auto &Registers = Target.getRegBank().getRegisters();
const std::vector<Record*> &AltNameIndices = Target.getRegAltNameIndices();
bool hasAltNames = AltNameIndices.size() > 1;
StringRef Namespace = Registers.front().TheDef->getValueAsString("Namespace");
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 << "::";
if (hasAltNames)
O << "\ngetRegisterName(unsigned RegNo, unsigned AltIdx) {\n";
else
O << "getRegisterName(unsigned RegNo) {\n";
O << " assert(RegNo && RegNo < " << (Registers.size()+1)
<< " && \"Invalid register number!\");\n"
<< "\n";
if (hasAltNames) {
for (const Record *R : AltNameIndices)
emitRegisterNameString(O, R->getName(), Registers);
} else
emitRegisterNameString(O, "", Registers);
if (hasAltNames) {
O << " switch(AltIdx) {\n"
<< " default: llvm_unreachable(\"Invalid register alt name index!\");\n";
for (const Record *R : AltNameIndices) {
StringRef AltName = R->getName();
O << " case ";
if (!Namespace.empty())
O << Namespace << "::";
O << AltName << ":\n";
if (R->isValueUnset("FallbackRegAltNameIndex"))
O << " assert(*(AsmStrs" << AltName << "+RegAsmOffset" << AltName
<< "[RegNo-1]) &&\n"
<< " \"Invalid alt name index for register!\");\n";
else {
O << " if (!*(AsmStrs" << AltName << "+RegAsmOffset" << AltName
<< "[RegNo-1]))\n"
<< " return getRegisterName(RegNo, ";
if (!Namespace.empty())
O << Namespace << "::";
O << R->getValueAsDef("FallbackRegAltNameIndex")->getName() << ");\n";
}
O << " return AsmStrs" << AltName << "+RegAsmOffset" << AltName
<< "[RegNo-1];\n";
}
O << " }\n";
} else {
O << " assert (*(AsmStrs+RegAsmOffset[RegNo-1]) &&\n"
<< " \"Invalid alt name index for register!\");\n"
<< " return AsmStrs+RegAsmOffset[RegNo-1];\n";
}
O << "}\n";
}
namespace {
// IAPrinter - Holds information about an InstAlias. Two InstAliases match if
// they both have the same conditionals. In which case, we cannot print out the
// alias for that pattern.
class IAPrinter {
std::map<StringRef, std::pair<int, int>> OpMap;
std::vector<std::string> Conds;
std::string Result;
std::string AsmString;
unsigned NumMIOps;
public:
IAPrinter(std::string R, std::string AS, unsigned NumMIOps)
: Result(std::move(R)), AsmString(std::move(AS)), NumMIOps(NumMIOps) {}
void addCond(std::string C) { Conds.push_back(std::move(C)); }
ArrayRef<std::string> getConds() const { return Conds; }
size_t getCondCount() const { return Conds.size(); }
void addOperand(StringRef Op, int OpIdx, int PrintMethodIdx = -1) {
assert(OpIdx >= 0 && OpIdx < 0xFE && "Idx out of range");
assert(PrintMethodIdx >= -1 && PrintMethodIdx < 0xFF &&
"Idx out of range");
OpMap[Op] = std::make_pair(OpIdx, PrintMethodIdx);
}
unsigned getNumMIOps() { return NumMIOps; }
StringRef getResult() { return Result; }
bool isOpMapped(StringRef Op) { return OpMap.find(Op) != OpMap.end(); }
int getOpIndex(StringRef Op) { return OpMap[Op].first; }
std::pair<int, int> &getOpData(StringRef Op) { return OpMap[Op]; }
std::pair<StringRef, StringRef::iterator> parseName(StringRef::iterator Start,
StringRef::iterator End) {
StringRef::iterator I = Start;
StringRef::iterator Next;
if (*I == '{') {
// ${some_name}
Start = ++I;
while (I != End && *I != '}')
++I;
Next = I;
// eat the final '}'
if (Next != End)
++Next;
} else {
// $name, just eat the usual suspects.
while (I != End &&
((*I >= 'a' && *I <= 'z') || (*I >= 'A' && *I <= 'Z') ||
(*I >= '0' && *I <= '9') || *I == '_'))
++I;
Next = I;
}
return std::make_pair(StringRef(Start, I - Start), Next);
}
std::string formatAliasString(uint32_t &UnescapedSize) {
// Directly mangle mapped operands into the string. Each operand is
// identified by a '$' sign followed by a byte identifying the number of the
// operand. We add one to the index to avoid zero bytes.
StringRef ASM(AsmString);
std::string OutString;
raw_string_ostream OS(OutString);
for (StringRef::iterator I = ASM.begin(), E = ASM.end(); I != E;) {
OS << *I;
++UnescapedSize;
if (*I == '$') {
StringRef Name;
std::tie(Name, I) = parseName(++I, E);
assert(isOpMapped(Name) && "Unmapped operand!");
int OpIndex, PrintIndex;
std::tie(OpIndex, PrintIndex) = getOpData(Name);
if (PrintIndex == -1) {
// Can use the default printOperand route.
OS << format("\\x%02X", (unsigned char)OpIndex + 1);
++UnescapedSize;
} else {
// 3 bytes if a PrintMethod is needed: 0xFF, the MCInst operand
// number, and which of our pre-detected Methods to call.
OS << format("\\xFF\\x%02X\\x%02X", OpIndex + 1, PrintIndex + 1);
UnescapedSize += 3;
}
} else {
++I;
}
}
OS.flush();
return OutString;
}
bool operator==(const IAPrinter &RHS) const {
if (NumMIOps != RHS.NumMIOps)
return false;
if (Conds.size() != RHS.Conds.size())
return false;
unsigned Idx = 0;
for (const auto &str : Conds)
if (str != RHS.Conds[Idx++])
return false;
return true;
}
};
} // end anonymous namespace
static unsigned CountNumOperands(StringRef AsmString, unsigned Variant) {
return AsmString.count(' ') + AsmString.count('\t');
}
namespace {
struct AliasPriorityComparator {
typedef std::pair<CodeGenInstAlias, int> ValueType;
bool operator()(const ValueType &LHS, const ValueType &RHS) const {
if (LHS.second == RHS.second) {
// We don't actually care about the order, but for consistency it
// shouldn't depend on pointer comparisons.
return LessRecordByID()(LHS.first.TheDef, RHS.first.TheDef);
}
// Aliases with larger priorities should be considered first.
return LHS.second > RHS.second;
}
};
} // end anonymous namespace
void AsmWriterEmitter::EmitPrintAliasInstruction(raw_ostream &O) {
Record *AsmWriter = Target.getAsmWriter();
O << "\n#ifdef PRINT_ALIAS_INSTR\n";
O << "#undef PRINT_ALIAS_INSTR\n\n";
//////////////////////////////
// Gather information about aliases we need to print
//////////////////////////////
// Emit the method that prints the alias instruction.
StringRef ClassName = AsmWriter->getValueAsString("AsmWriterClassName");
unsigned Variant = AsmWriter->getValueAsInt("Variant");
bool PassSubtarget = AsmWriter->getValueAsInt("PassSubtarget");
std::vector<Record*> AllInstAliases =
Records.getAllDerivedDefinitions("InstAlias");
// Create a map from the qualified name to a list of potential matches.
typedef std::set<std::pair<CodeGenInstAlias, int>, AliasPriorityComparator>
AliasWithPriority;
std::map<std::string, AliasWithPriority> AliasMap;
for (Record *R : AllInstAliases) {
int Priority = R->getValueAsInt("EmitPriority");
if (Priority < 1)
continue; // Aliases with priority 0 are never emitted.
const DagInit *DI = R->getValueAsDag("ResultInst");
AliasMap[getQualifiedName(DI->getOperatorAsDef(R->getLoc()))].insert(
std::make_pair(CodeGenInstAlias(R, Target), Priority));
}
// A map of which conditions need to be met for each instruction operand
// before it can be matched to the mnemonic.
std::map<std::string, std::vector<IAPrinter>> IAPrinterMap;
std::vector<std::string> PrintMethods;
// A list of MCOperandPredicates for all operands in use, and the reverse map
std::vector<const Record*> MCOpPredicates;
DenseMap<const Record*, unsigned> MCOpPredicateMap;
for (auto &Aliases : AliasMap) {
// Collection of instruction alias rules. May contain ambiguous rules.
std::vector<IAPrinter> IAPs;
for (auto &Alias : Aliases.second) {
const CodeGenInstAlias &CGA = Alias.first;
unsigned LastOpNo = CGA.ResultInstOperandIndex.size();
std::string FlatInstAsmString =
CodeGenInstruction::FlattenAsmStringVariants(CGA.ResultInst->AsmString,
Variant);
unsigned NumResultOps = CountNumOperands(FlatInstAsmString, Variant);
std::string FlatAliasAsmString =
CodeGenInstruction::FlattenAsmStringVariants(CGA.AsmString, Variant);
// Don't emit the alias if it has more operands than what it's aliasing.
if (NumResultOps < CountNumOperands(FlatAliasAsmString, Variant))
continue;
StringRef Namespace = Target.getName();
unsigned NumMIOps = 0;
for (auto &ResultInstOpnd : CGA.ResultInst->Operands)
NumMIOps += ResultInstOpnd.MINumOperands;
IAPrinter IAP(CGA.Result->getAsString(), FlatAliasAsmString, NumMIOps);
bool CantHandle = false;
unsigned MIOpNum = 0;
for (unsigned i = 0, e = LastOpNo; i != e; ++i) {
// Skip over tied operands as they're not part of an alias declaration.
auto &Operands = CGA.ResultInst->Operands;
while (true) {
unsigned OpNum = Operands.getSubOperandNumber(MIOpNum).first;
if (Operands[OpNum].MINumOperands == 1 &&
Operands[OpNum].getTiedRegister() != -1) {
// Tied operands of different RegisterClass should be explicit within
// an instruction's syntax and so cannot be skipped.
int TiedOpNum = Operands[OpNum].getTiedRegister();
if (Operands[OpNum].Rec->getName() ==
Operands[TiedOpNum].Rec->getName()) {
++MIOpNum;
continue;
}
}
break;
}
// Ignore unchecked result operands.
while (IAP.getCondCount() < MIOpNum)
IAP.addCond("AliasPatternCond::K_Ignore, 0");
const CodeGenInstAlias::ResultOperand &RO = CGA.ResultOperands[i];
switch (RO.Kind) {
case CodeGenInstAlias::ResultOperand::K_Record: {
const Record *Rec = RO.getRecord();
StringRef ROName = RO.getName();
int PrintMethodIdx = -1;
// These two may have a PrintMethod, which we want to record (if it's
// the first time we've seen it) and provide an index for the aliasing
// code to use.
if (Rec->isSubClassOf("RegisterOperand") ||
Rec->isSubClassOf("Operand")) {
StringRef PrintMethod = Rec->getValueAsString("PrintMethod");
if (PrintMethod != "" && PrintMethod != "printOperand") {
PrintMethodIdx =
llvm::find(PrintMethods, PrintMethod) - PrintMethods.begin();
if (static_cast<unsigned>(PrintMethodIdx) == PrintMethods.size())
PrintMethods.push_back(std::string(PrintMethod));
}
}
if (Rec->isSubClassOf("RegisterOperand"))
Rec = Rec->getValueAsDef("RegClass");
if (Rec->isSubClassOf("RegisterClass")) {
if (!IAP.isOpMapped(ROName)) {
IAP.addOperand(ROName, MIOpNum, PrintMethodIdx);
Record *R = CGA.ResultOperands[i].getRecord();
if (R->isSubClassOf("RegisterOperand"))
R = R->getValueAsDef("RegClass");
IAP.addCond(std::string(
formatv("AliasPatternCond::K_RegClass, {0}::{1}RegClassID",
Namespace, R->getName())));
} else {
IAP.addCond(std::string(formatv(
"AliasPatternCond::K_TiedReg, {0}", IAP.getOpIndex(ROName))));
}
} else {
// Assume all printable operands are desired for now. This can be
// overridden in the InstAlias instantiation if necessary.
IAP.addOperand(ROName, MIOpNum, PrintMethodIdx);
// There might be an additional predicate on the MCOperand
unsigned Entry = MCOpPredicateMap[Rec];
if (!Entry) {
if (!Rec->isValueUnset("MCOperandPredicate")) {
MCOpPredicates.push_back(Rec);
Entry = MCOpPredicates.size();
MCOpPredicateMap[Rec] = Entry;
} else
break; // No conditions on this operand at all
}
IAP.addCond(
std::string(formatv("AliasPatternCond::K_Custom, {0}", Entry)));
}
break;
}
case CodeGenInstAlias::ResultOperand::K_Imm: {
// Just because the alias has an immediate result, doesn't mean the
// MCInst will. An MCExpr could be present, for example.
auto Imm = CGA.ResultOperands[i].getImm();
int32_t Imm32 = int32_t(Imm);
if (Imm != Imm32)
PrintFatalError("Matching an alias with an immediate out of the "
"range of int32_t is not supported");
IAP.addCond(std::string(
formatv("AliasPatternCond::K_Imm, uint32_t({0})", Imm32)));
break;
}
case CodeGenInstAlias::ResultOperand::K_Reg:
// If this is zero_reg, something's playing tricks we're not
// equipped to handle.
if (!CGA.ResultOperands[i].getRegister()) {
CantHandle = true;
break;
}
StringRef Reg = CGA.ResultOperands[i].getRegister()->getName();
IAP.addCond(std::string(
formatv("AliasPatternCond::K_Reg, {0}::{1}", Namespace, Reg)));
break;
}
MIOpNum += RO.getMINumOperands();
}
if (CantHandle) continue;
std::vector<Record *> ReqFeatures;
if (PassSubtarget) {
// We only consider ReqFeatures predicates if PassSubtarget
std::vector<Record *> RF =
CGA.TheDef->getValueAsListOfDefs("Predicates");
copy_if(RF, std::back_inserter(ReqFeatures), [](Record *R) {
return R->getValueAsBit("AssemblerMatcherPredicate");
});
}
for (auto I = ReqFeatures.cbegin(); I != ReqFeatures.cend(); I++) {
Record *R = *I;
StringRef AsmCondString = R->getValueAsString("AssemblerCondString");
// AsmCondString has syntax [!]F(,[!]F)*
SmallVector<StringRef, 4> Ops;
SplitString(AsmCondString, Ops, ",");
assert(!Ops.empty() && "AssemblerCondString cannot be empty");
for (StringRef Op : Ops) {
assert(!Op.empty() && "Empty operator");
bool IsNeg = Op[0] == '!';
StringRef Feature = Op.drop_front(IsNeg ? 1 : 0);
IAP.addCond(
std::string(formatv("AliasPatternCond::K_{0}Feature, {1}::{2}",
IsNeg ? "Neg" : "", Namespace, Feature)));
}
}
IAPrinterMap[Aliases.first].push_back(std::move(IAP));
}
}
//////////////////////////////
// Write out the printAliasInstr function
//////////////////////////////
std::string Header;
raw_string_ostream HeaderO(Header);
HeaderO << "bool " << Target.getName() << ClassName
<< "::printAliasInstr(const MCInst"
<< " *MI, " << (PassSubtarget ? "const MCSubtargetInfo &STI, " : "")
<< "raw_ostream &OS) {\n";
std::string PatternsForOpcode;
raw_string_ostream OpcodeO(PatternsForOpcode);
unsigned PatternCount = 0;
std::string Patterns;
raw_string_ostream PatternO(Patterns);
unsigned CondCount = 0;
std::string Conds;
raw_string_ostream CondO(Conds);
// All flattened alias strings.
std::map<std::string, uint32_t> AsmStringOffsets;
std::vector<std::pair<uint32_t, std::string>> AsmStrings;
size_t AsmStringsSize = 0;
// Iterate over the opcodes in enum order so they are sorted by opcode for
// binary search.
for (const CodeGenInstruction *Inst : NumberedInstructions) {
auto It = IAPrinterMap.find(getQualifiedName(Inst->TheDef));
if (It == IAPrinterMap.end())
continue;
std::vector<IAPrinter> &IAPs = It->second;
std::vector<IAPrinter*> UniqueIAPs;
// Remove any ambiguous alias rules.
for (auto &LHS : IAPs) {
bool IsDup = false;
for (const auto &RHS : IAPs) {
if (&LHS != &RHS && LHS == RHS) {
IsDup = true;
break;
}
}
if (!IsDup)
UniqueIAPs.push_back(&LHS);
}
if (UniqueIAPs.empty()) continue;
unsigned PatternStart = PatternCount;
// Insert the pattern start and opcode in the pattern list for debugging.
PatternO << formatv(" // {0} - {1}\n", It->first, PatternStart);
for (IAPrinter *IAP : UniqueIAPs) {
// Start each condition list with a comment of the resulting pattern that
// we're trying to match.
unsigned CondStart = CondCount;
CondO << formatv(" // {0} - {1}\n", IAP->getResult(), CondStart);
for (const auto &Cond : IAP->getConds())
CondO << " {" << Cond << "},\n";
CondCount += IAP->getCondCount();
// After operands have been examined, re-encode the alias string with
// escapes indicating how operands should be printed.
uint32_t UnescapedSize = 0;
std::string EncodedAsmString = IAP->formatAliasString(UnescapedSize);
auto Insertion =
AsmStringOffsets.insert({EncodedAsmString, AsmStringsSize});
if (Insertion.second) {
// If the string is new, add it to the vector.
AsmStrings.push_back({AsmStringsSize, EncodedAsmString});
AsmStringsSize += UnescapedSize + 1;
}
unsigned AsmStrOffset = Insertion.first->second;
PatternO << formatv(" {{{0}, {1}, {2}, {3} },\n", AsmStrOffset,
CondStart, IAP->getNumMIOps(), IAP->getCondCount());
++PatternCount;
}
OpcodeO << formatv(" {{{0}, {1}, {2} },\n", It->first, PatternStart,
PatternCount - PatternStart);
}
if (OpcodeO.str().empty()) {
O << HeaderO.str();
O << " return false;\n";
O << "}\n\n";
O << "#endif // PRINT_ALIAS_INSTR\n";
return;
}
// Forward declare the validation method if needed.
if (!MCOpPredicates.empty())
O << "static bool " << Target.getName() << ClassName
<< "ValidateMCOperand(const MCOperand &MCOp,\n"
<< " const MCSubtargetInfo &STI,\n"
<< " unsigned PredicateIndex);\n";
O << HeaderO.str();
O.indent(2) << "static const PatternsForOpcode OpToPatterns[] = {\n";
O << OpcodeO.str();
O.indent(2) << "};\n\n";
O.indent(2) << "static const AliasPattern Patterns[] = {\n";
O << PatternO.str();
O.indent(2) << "};\n\n";
O.indent(2) << "static const AliasPatternCond Conds[] = {\n";
O << CondO.str();
O.indent(2) << "};\n\n";
O.indent(2) << "static const char AsmStrings[] =\n";
for (const auto &P : AsmStrings) {
O.indent(4) << "/* " << P.first << " */ \"" << P.second << "\\0\"\n";
}
O.indent(2) << ";\n\n";
// Assert that the opcode table is sorted. Use a static local constructor to
// ensure that the check only happens once on first run.
O << "#ifndef NDEBUG\n";
O.indent(2) << "static struct SortCheck {\n";
O.indent(2) << " SortCheck(ArrayRef<PatternsForOpcode> OpToPatterns) {\n";
O.indent(2) << " assert(std::is_sorted(\n";
O.indent(2) << " OpToPatterns.begin(), OpToPatterns.end(),\n";
O.indent(2) << " [](const PatternsForOpcode &L, const "
"PatternsForOpcode &R) {\n";
O.indent(2) << " return L.Opcode < R.Opcode;\n";
O.indent(2) << " }) &&\n";
O.indent(2) << " \"tablegen failed to sort opcode patterns\");\n";
O.indent(2) << " }\n";
O.indent(2) << "} sortCheckVar(OpToPatterns);\n";
O << "#endif\n\n";
O.indent(2) << "AliasMatchingData M {\n";
O.indent(2) << " makeArrayRef(OpToPatterns),\n";
O.indent(2) << " makeArrayRef(Patterns),\n";
O.indent(2) << " makeArrayRef(Conds),\n";
O.indent(2) << " StringRef(AsmStrings, array_lengthof(AsmStrings)),\n";
if (MCOpPredicates.empty())
O.indent(2) << " nullptr,\n";
else
O.indent(2) << " &" << Target.getName() << ClassName << "ValidateMCOperand,\n";
O.indent(2) << "};\n";
O.indent(2) << "const char *AsmString = matchAliasPatterns(MI, "
<< (PassSubtarget ? "&STI" : "nullptr") << ", M);\n";
O.indent(2) << "if (!AsmString) return false;\n\n";
// Code that prints the alias, replacing the operands with the ones from the
// MCInst.
O << " unsigned I = 0;\n";
O << " while (AsmString[I] != ' ' && AsmString[I] != '\\t' &&\n";
O << " AsmString[I] != '$' && AsmString[I] != '\\0')\n";
O << " ++I;\n";
O << " OS << '\\t' << StringRef(AsmString, I);\n";
O << " if (AsmString[I] != '\\0') {\n";
O << " if (AsmString[I] == ' ' || AsmString[I] == '\\t') {\n";
O << " OS << '\\t';\n";
O << " ++I;\n";
O << " }\n";
O << " do {\n";
O << " if (AsmString[I] == '$') {\n";
O << " ++I;\n";
O << " if (AsmString[I] == (char)0xff) {\n";
O << " ++I;\n";
O << " int OpIdx = AsmString[I++] - 1;\n";
O << " int PrintMethodIdx = AsmString[I++] - 1;\n";
O << " printCustomAliasOperand(MI, OpIdx, PrintMethodIdx, ";
O << (PassSubtarget ? "STI, " : "");
O << "OS);\n";
O << " } else\n";
O << " printOperand(MI, unsigned(AsmString[I++]) - 1, ";
O << (PassSubtarget ? "STI, " : "");
O << "OS);\n";
O << " } else {\n";
O << " OS << AsmString[I++];\n";
O << " }\n";
O << " } while (AsmString[I] != '\\0');\n";
O << " }\n\n";
O << " return true;\n";
O << "}\n\n";
//////////////////////////////
// Write out the printCustomAliasOperand function
//////////////////////////////
O << "void " << Target.getName() << ClassName << "::"
<< "printCustomAliasOperand(\n"
<< " const MCInst *MI, unsigned OpIdx,\n"
<< " unsigned PrintMethodIdx,\n"
<< (PassSubtarget ? " const MCSubtargetInfo &STI,\n" : "")
<< " raw_ostream &OS) {\n";
if (PrintMethods.empty())
O << " llvm_unreachable(\"Unknown PrintMethod kind\");\n";
else {
O << " switch (PrintMethodIdx) {\n"
<< " default:\n"
<< " llvm_unreachable(\"Unknown PrintMethod kind\");\n"
<< " break;\n";
for (unsigned i = 0; i < PrintMethods.size(); ++i) {
O << " case " << i << ":\n"
<< " " << PrintMethods[i] << "(MI, OpIdx, "
<< (PassSubtarget ? "STI, " : "") << "OS);\n"
<< " break;\n";
}
O << " }\n";
}
O << "}\n\n";
if (!MCOpPredicates.empty()) {
O << "static bool " << Target.getName() << ClassName
<< "ValidateMCOperand(const MCOperand &MCOp,\n"
<< " const MCSubtargetInfo &STI,\n"
<< " unsigned PredicateIndex) {\n"
<< " switch (PredicateIndex) {\n"
<< " default:\n"
<< " llvm_unreachable(\"Unknown MCOperandPredicate kind\");\n"
<< " break;\n";
for (unsigned i = 0; i < MCOpPredicates.size(); ++i) {
Init *MCOpPred = MCOpPredicates[i]->getValueInit("MCOperandPredicate");
if (CodeInit *SI = dyn_cast<CodeInit>(MCOpPred)) {
O << " case " << i + 1 << ": {\n"
<< SI->getValue() << "\n"
<< " }\n";
} else
llvm_unreachable("Unexpected MCOperandPredicate field!");
}
O << " }\n"
<< "}\n\n";
}
O << "#endif // PRINT_ALIAS_INSTR\n";
}
AsmWriterEmitter::AsmWriterEmitter(RecordKeeper &R) : Records(R), Target(R) {
Record *AsmWriter = Target.getAsmWriter();
unsigned Variant = AsmWriter->getValueAsInt("Variant");
// Get the instruction numbering.
NumberedInstructions = Target.getInstructionsByEnumValue();
for (unsigned i = 0, e = NumberedInstructions.size(); i != e; ++i) {
const CodeGenInstruction *I = NumberedInstructions[i];
if (!I->AsmString.empty() && I->TheDef->getName() != "PHI")
Instructions.emplace_back(*I, i, Variant);
}
}
void AsmWriterEmitter::run(raw_ostream &O) {
EmitPrintInstruction(O);
EmitGetRegisterName(O);
EmitPrintAliasInstruction(O);
}
namespace llvm {
void EmitAsmWriter(RecordKeeper &RK, raw_ostream &OS) {
emitSourceFileHeader("Assembly Writer Source Fragment", OS);
AsmWriterEmitter(RK).run(OS);
}
} // end namespace llvm
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