llvm/utils/TableGen/CodeEmitterGen.cpp
Evan Cheng a844bdeab3 SDIsel processes llvm.dbg.declare by recording the variable debug information descriptor and its corresponding stack frame index in MachineModuleInfo. This only works if the local variable is "homed" in the stack frame. It does not work for byval parameter, etc.
Added ISD::DECLARE node type to represent llvm.dbg.declare intrinsic. Now the intrinsic calls are lowered into a SDNode and lives on through out the codegen passes.
For now, since all the debugging information recording is done at isel time, when a ISD::DECLARE node is selected, it has the side effect of also recording the variable. This is a short term solution that should be fixed in time.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46659 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-02 04:07:54 +00:00

238 lines
7.8 KiB
C++

//===- CodeEmitterGen.cpp - Code Emitter Generator ------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// CodeEmitterGen uses the descriptions of instructions and their fields to
// construct an automated code emitter: a function that, given a MachineInstr,
// returns the (currently, 32-bit unsigned) value of the instruction.
//
//===----------------------------------------------------------------------===//
#include "CodeEmitterGen.h"
#include "CodeGenTarget.h"
#include "Record.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/Debug.h"
using namespace llvm;
void CodeEmitterGen::reverseBits(std::vector<Record*> &Insts) {
for (std::vector<Record*>::iterator I = Insts.begin(), E = Insts.end();
I != E; ++I) {
Record *R = *I;
if (R->getName() == "PHI" ||
R->getName() == "INLINEASM" ||
R->getName() == "LABEL" ||
R->getName() == "DECLARE" ||
R->getName() == "EXTRACT_SUBREG" ||
R->getName() == "INSERT_SUBREG") continue;
BitsInit *BI = R->getValueAsBitsInit("Inst");
unsigned numBits = BI->getNumBits();
BitsInit *NewBI = new BitsInit(numBits);
for (unsigned bit = 0, end = numBits / 2; bit != end; ++bit) {
unsigned bitSwapIdx = numBits - bit - 1;
Init *OrigBit = BI->getBit(bit);
Init *BitSwap = BI->getBit(bitSwapIdx);
NewBI->setBit(bit, BitSwap);
NewBI->setBit(bitSwapIdx, OrigBit);
}
if (numBits % 2) {
unsigned middle = (numBits + 1) / 2;
NewBI->setBit(middle, BI->getBit(middle));
}
// Update the bits in reversed order so that emitInstrOpBits will get the
// correct endianness.
R->getValue("Inst")->setValue(NewBI);
}
}
// If the VarBitInit at position 'bit' matches the specified variable then
// return the variable bit position. Otherwise return -1.
int CodeEmitterGen::getVariableBit(const std::string &VarName,
BitsInit *BI, int bit) {
if (VarBitInit *VBI = dynamic_cast<VarBitInit*>(BI->getBit(bit))) {
TypedInit *TI = VBI->getVariable();
if (VarInit *VI = dynamic_cast<VarInit*>(TI)) {
if (VI->getName() == VarName) return VBI->getBitNum();
}
}
return -1;
}
void CodeEmitterGen::run(std::ostream &o) {
CodeGenTarget Target;
std::vector<Record*> Insts = Records.getAllDerivedDefinitions("Instruction");
// For little-endian instruction bit encodings, reverse the bit order
if (Target.isLittleEndianEncoding()) reverseBits(Insts);
EmitSourceFileHeader("Machine Code Emitter", o);
std::string Namespace = Insts[0]->getValueAsString("Namespace") + "::";
std::vector<const CodeGenInstruction*> NumberedInstructions;
Target.getInstructionsByEnumValue(NumberedInstructions);
// Emit function declaration
o << "unsigned " << Target.getName() << "CodeEmitter::"
<< "getBinaryCodeForInstr(MachineInstr &MI) {\n";
// Emit instruction base values
o << " static const unsigned InstBits[] = {\n";
for (std::vector<const CodeGenInstruction*>::iterator
IN = NumberedInstructions.begin(),
EN = NumberedInstructions.end();
IN != EN; ++IN) {
const CodeGenInstruction *CGI = *IN;
Record *R = CGI->TheDef;
if (IN != NumberedInstructions.begin()) o << ",\n";
if (R->getName() == "PHI" ||
R->getName() == "INLINEASM" ||
R->getName() == "LABEL" ||
R->getName() == "DECLARE" ||
R->getName() == "EXTRACT_SUBREG" ||
R->getName() == "INSERT_SUBREG") {
o << " 0U";
continue;
}
BitsInit *BI = R->getValueAsBitsInit("Inst");
// Start by filling in fixed values...
unsigned Value = 0;
for (unsigned i = 0, e = BI->getNumBits(); i != e; ++i) {
if (BitInit *B = dynamic_cast<BitInit*>(BI->getBit(e-i-1))) {
Value |= B->getValue() << (e-i-1);
}
}
o << " " << Value << "U";
}
o << "\n };\n";
// Map to accumulate all the cases.
std::map<std::string, std::vector<std::string> > CaseMap;
// Construct all cases statement for each opcode
for (std::vector<Record*>::iterator IC = Insts.begin(), EC = Insts.end();
IC != EC; ++IC) {
Record *R = *IC;
const std::string &InstName = R->getName();
std::string Case("");
if (InstName == "PHI" ||
InstName == "INLINEASM" ||
InstName == "LABEL"||
InstName == "DECLARE"||
InstName == "EXTRACT_SUBREG" ||
InstName == "INSERT_SUBREG") continue;
BitsInit *BI = R->getValueAsBitsInit("Inst");
const std::vector<RecordVal> &Vals = R->getValues();
CodeGenInstruction &CGI = Target.getInstruction(InstName);
// Loop over all of the fields in the instruction, determining which are the
// operands to the instruction.
unsigned op = 0;
for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
if (!Vals[i].getPrefix() && !Vals[i].getValue()->isComplete()) {
// Is the operand continuous? If so, we can just mask and OR it in
// instead of doing it bit-by-bit, saving a lot in runtime cost.
const std::string &VarName = Vals[i].getName();
bool gotOp = false;
for (int bit = BI->getNumBits()-1; bit >= 0; ) {
int varBit = getVariableBit(VarName, BI, bit);
if (varBit == -1) {
--bit;
} else {
int beginInstBit = bit;
int beginVarBit = varBit;
int N = 1;
for (--bit; bit >= 0;) {
varBit = getVariableBit(VarName, BI, bit);
if (varBit == -1 || varBit != (beginVarBit - N)) break;
++N;
--bit;
}
if (!gotOp) {
/// If this operand is not supposed to be emitted by the generated
/// emitter, skip it.
while (CGI.isFlatOperandNotEmitted(op))
++op;
Case += " // op: " + VarName + "\n"
+ " op = getMachineOpValue(MI, MI.getOperand("
+ utostr(op++) + "));\n";
gotOp = true;
}
unsigned opMask = (1 << N) - 1;
int opShift = beginVarBit - N + 1;
opMask <<= opShift;
opShift = beginInstBit - beginVarBit;
if (opShift > 0) {
Case += " Value |= (op & " + utostr(opMask) + "U) << "
+ itostr(opShift) + ";\n";
} else if (opShift < 0) {
Case += " Value |= (op & " + utostr(opMask) + "U) >> "
+ itostr(-opShift) + ";\n";
} else {
Case += " Value |= op & " + utostr(opMask) + "U;\n";
}
}
}
}
}
std::vector<std::string> &InstList = CaseMap[Case];
InstList.push_back(InstName);
}
// Emit initial function code
o << " const unsigned opcode = MI.getOpcode();\n"
<< " unsigned Value = InstBits[opcode];\n"
<< " unsigned op;\n"
<< " switch (opcode) {\n";
// Emit each case statement
std::map<std::string, std::vector<std::string> >::iterator IE, EE;
for (IE = CaseMap.begin(), EE = CaseMap.end(); IE != EE; ++IE) {
const std::string &Case = IE->first;
std::vector<std::string> &InstList = IE->second;
for (int i = 0, N = InstList.size(); i < N; i++) {
if (i) o << "\n";
o << " case " << Namespace << InstList[i] << ":";
}
o << " {\n";
o << Case;
o << " break;\n"
<< " }\n";
}
// Default case: unhandled opcode
o << " default:\n"
<< " cerr << \"Not supported instr: \" << MI << \"\\n\";\n"
<< " abort();\n"
<< " }\n"
<< " return Value;\n"
<< "}\n\n";
}