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//===- AsmWriterEmitter.cpp - Generate an assembly writer -----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and 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 "CodeGenTarget.h"
#include "Record.h"
#include <ostream>
using namespace llvm;
static bool isIdentChar(char C) {
return (C >= 'a' && C <= 'z') ||
(C >= 'A' && C <= 'Z') ||
(C >= '0' && C <= '9') ||
C == '_';
}
void AsmWriterEmitter::run(std::ostream &O) {
EmitSourceFileHeader("Assembly Writer Source Fragment", O);
O << "namespace llvm {\n\n";
CodeGenTarget Target;
Record *AsmWriter = Target.getAsmWriter();
std::string ClassName = AsmWriter->getValueAsString("AsmWriterClassName");
unsigned Variant = AsmWriter->getValueAsInt("Variant");
O <<
"/// printInstruction - This method is automatically generated by tablegen\n"
"/// from the instruction set description. This method returns true if the\n"
"/// machine instruction was sufficiently described to print it, otherwise\n"
"/// it returns false.\n"
"bool " << Target.getName() << ClassName
<< "::printInstruction(const MachineInstr *MI) {\n";
O << " switch (MI->getOpcode()) {\n"
" default: return false;\n";
std::string Namespace = Target.inst_begin()->second.Namespace;
bool inVariant = false; // True if we are inside a {.|.|.} region.
for (CodeGenTarget::inst_iterator I = Target.inst_begin(),
E = Target.inst_end(); I != E; ++I)
if (!I->second.AsmString.empty()) {
const std::string &AsmString = I->second.AsmString;
O << " case " << Namespace << "::" << I->first << ": O ";
std::string::size_type LastEmitted = 0;
while (LastEmitted != AsmString.size()) {
std::string::size_type DollarPos =
AsmString.find_first_of("${|}", LastEmitted);
if (DollarPos == std::string::npos) DollarPos = AsmString.size();
// Emit a constant string fragment.
if (DollarPos != LastEmitted) {
// TODO: this should eventually handle escaping.
O << " << \"" << std::string(AsmString.begin()+LastEmitted,
AsmString.begin()+DollarPos) << "\"";
LastEmitted = DollarPos;
} else if (AsmString[DollarPos] == '{') {
if (inVariant)
throw "Nested variants found for instruction '" + I->first + "'!";
LastEmitted = DollarPos+1;
inVariant = true; // We are now inside of the variant!
for (unsigned i = 0; i != Variant; ++i) {
// Skip over all of the text for an irrelevant variant here. The
// next variant starts at |, or there may not be text for this
// variant if we see a }.
std::string::size_type NP =
AsmString.find_first_of("|}", LastEmitted);
if (NP == std::string::npos)
throw "Incomplete variant for instruction '" + I->first + "'!";
LastEmitted = NP+1;
if (AsmString[NP] == '}') {
inVariant = false; // No text for this variant.
break;
}
}
} else if (AsmString[DollarPos] == '|') {
if (!inVariant)
throw "'|' character found outside of a variant in instruction '"
+ I->first + "'!";
// Move to the end of variant list.
std::string::size_type NP = AsmString.find('}', LastEmitted);
if (NP == std::string::npos)
throw "Incomplete variant for instruction '" + I->first + "'!";
LastEmitted = NP+1;
inVariant = false;
} else if (AsmString[DollarPos] == '}') {
if (!inVariant)
throw "'}' character found outside of a variant in instruction '"
+ I->first + "'!";
LastEmitted = DollarPos+1;
inVariant = false;
} else if (DollarPos+1 != AsmString.size() &&
AsmString[DollarPos+1] == '$') {
O << " << '$'"; // "$$" -> $
} else {
// Get the name of the variable.
// TODO: should eventually handle ${foo}bar as $foo
std::string::size_type VarEnd = DollarPos+1;
while (VarEnd < AsmString.size() && isIdentChar(AsmString[VarEnd]))
++VarEnd;
std::string VarName(AsmString.begin()+DollarPos+1,
AsmString.begin()+VarEnd);
if (VarName.empty())
throw "Stray '$' in '" + I->first +
"' asm string, maybe you want $$?";
unsigned OpNo = I->second.getOperandNamed(VarName);
// If this is a two-address instruction and we are not accessing the
// 0th operand, remove an operand.
unsigned MIOp = I->second.OperandList[OpNo].MIOperandNo;
if (I->second.isTwoAddress && MIOp != 0) {
if (MIOp == 1)
throw "Should refer to operand #0 instead of #1 for two-address"
" instruction '" + I->first + "'!";
--MIOp;
}
O << "; " << I->second.OperandList[OpNo].PrinterMethodName
<< "(MI, " << MIOp << ", MVT::"
<< getName(I->second.OperandList[OpNo].Ty) << "); O ";
LastEmitted = VarEnd;
}
}
O << " << '\\n'; break;\n";
}
O << " }\n"
" return true;\n"
"}\n";
O << "} // End llvm namespace \n";
}
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