llvm-6502/lib/Target/SparcV9/EmitBytecodeToAssembly.cpp

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//===-- EmitBytecodeToAssembly.cpp - Emit bytecode to SparcV9 .s File --------==//
//
// 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 file implements the pass that writes LLVM bytecode as data to a sparc
// assembly file. The bytecode gets assembled into a special bytecode section
// of the executable for use at runtime later.
//
//===----------------------------------------------------------------------===//
#include "SparcV9Internals.h"
#include "llvm/Pass.h"
#include "llvm/Bytecode/Writer.h"
#include <iostream>
namespace llvm {
using std::ostream;
namespace {
// sparcasmbuf - stream buf for encoding output bytes as .byte directives for
// the sparc assembler.
//
class sparcasmbuf : public std::streambuf {
std::ostream &BaseStr;
public:
typedef char char_type;
typedef int int_type;
typedef std::streampos pos_type;
typedef std::streamoff off_type;
sparcasmbuf(std::ostream &On) : BaseStr(On) {}
virtual int_type overflow(int_type C) {
if (C != EOF)
BaseStr << "\t.byte " << C << "\n"; // Output C;
return C;
}
};
// osparcasmstream - Define an ostream implementation that uses a sparcasmbuf
// as the underlying streambuf to write the data to. This streambuf formats
// the output as .byte directives for sparc output.
//
class osparcasmstream : public std::ostream {
sparcasmbuf sb;
public:
typedef char char_type;
typedef int int_type;
typedef std::streampos pos_type;
typedef std::streamoff off_type;
explicit osparcasmstream(std::ostream &On) : std::ostream(&sb), sb(On) { }
sparcasmbuf *rdbuf() const {
return const_cast<sparcasmbuf*>(&sb);
}
};
static void writePrologue (std::ostream &Out, const std::string &comment,
const std::string &symName) {
// Prologue:
// Output a comment describing the object.
Out << "!" << comment << "\n";
// Switch the current section to .rodata in the assembly output:
Out << "\t.section \".rodata\"\n\t.align 8\n";
// Output a global symbol naming the object:
Out << "\t.global " << symName << "\n";
Out << "\t.type " << symName << ",#object\n";
Out << symName << ":\n";
}
static void writeEpilogue (std::ostream &Out, const std::string &symName) {
// Epilogue:
// Output a local symbol marking the end of the object:
Out << ".end_" << symName << ":\n";
// Output size directive giving the size of the object:
Out << "\t.size " << symName << ", .end_" << symName << "-" << symName
<< "\n";
}
// SparcV9BytecodeWriter - Write bytecode out to a stream that is sparc'ified
class SparcV9BytecodeWriter : public Pass {
std::ostream &Out;
public:
SparcV9BytecodeWriter(std::ostream &out) : Out(out) {}
const char *getPassName() const { return "Emit Bytecode to SparcV9 Assembly";}
virtual bool run(Module &M) {
// Write an object containing the bytecode to the SPARC assembly stream
writePrologue (Out, "LLVM BYTECODE OUTPUT", "LLVMBytecode");
osparcasmstream OS(Out);
WriteBytecodeToFile(&M, OS);
writeEpilogue (Out, "LLVMBytecode");
// Write an object containing its length as an integer to the
// SPARC assembly stream
writePrologue (Out, "LLVM BYTECODE LENGTH", "llvm_length");
Out <<"\t.word\t.end_LLVMBytecode-LLVMBytecode\n";
writeEpilogue (Out, "llvm_length");
return false;
}
};
} // end anonymous namespace
Pass *createBytecodeAsmPrinterPass(std::ostream &Out) {
return new SparcV9BytecodeWriter(Out);
}
} // End llvm namespace