Move [SU]LEB128 encoding to a utility header.

These functions are very generic. There's no reason for them to
be tied to MCObjectWriter.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161545 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jim Grosbach 2012-08-08 23:56:06 +00:00
parent fdd6484b41
commit 2d39a0e52d
6 changed files with 68 additions and 46 deletions

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@ -182,11 +182,6 @@ public:
/// @}
/// Utility function to encode a SLEB128 value.
static void EncodeSLEB128(int64_t Value, raw_ostream &OS);
/// Utility function to encode a ULEB128 value.
static void EncodeULEB128(uint64_t Value, raw_ostream &OS,
unsigned Padding = 0);
};
} // End llvm namespace

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@ -0,0 +1,58 @@
//===- llvm/Support/LEB128.h - [SU]LEB128 utility functions -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares some utility functions for encoding SLEB128 and
// ULEB128 values.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SYSTEM_LEB128_H
#define LLVM_SYSTEM_LEB128_H
#include <llvm/Support/raw_ostream.h>
namespace llvm {
/// Utility function to encode a SLEB128 value.
static inline void encodeSLEB128(int64_t Value, raw_ostream &OS) {
bool More;
do {
uint8_t Byte = Value & 0x7f;
// NOTE: this assumes that this signed shift is an arithmetic right shift.
Value >>= 7;
More = !((((Value == 0 ) && ((Byte & 0x40) == 0)) ||
((Value == -1) && ((Byte & 0x40) != 0))));
if (More)
Byte |= 0x80; // Mark this byte that that more bytes will follow.
OS << char(Byte);
} while (More);
}
/// Utility function to encode a ULEB128 value.
static inline void encodeULEB128(uint64_t Value, raw_ostream &OS,
unsigned Padding = 0) {
do {
uint8_t Byte = Value & 0x7f;
Value >>= 7;
if (Value != 0 || Padding != 0)
Byte |= 0x80; // Mark this byte that that more bytes will follow.
OS << char(Byte);
} while (Value != 0);
// Pad with 0x80 and emit a null byte at the end.
if (Padding != 0) {
for (; Padding != 1; --Padding)
OS << '\x80';
OS << '\x00';
}
}
} // namespace llvm
#endif // LLVM_SYSTEM_LEB128_H

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@ -27,6 +27,7 @@
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/LEB128.h"
using namespace llvm;
@ -713,9 +714,9 @@ bool MCAssembler::relaxLEB(MCAsmLayout &Layout, MCLEBFragment &LF) {
Data.clear();
raw_svector_ostream OSE(Data);
if (LF.isSigned())
MCObjectWriter::EncodeSLEB128(Value, OSE);
encodeSLEB128(Value, OSE);
else
MCObjectWriter::EncodeULEB128(Value, OSE);
encodeULEB128(Value, OSE);
OSE.flush();
return OldSize != LF.getContents().size();
}

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@ -19,6 +19,7 @@
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/LEB128.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/ADT/Hashing.h"
@ -361,7 +362,7 @@ void MCDwarfLineAddr::Encode(int64_t LineDelta, uint64_t AddrDelta,
OS << char(dwarf::DW_LNS_const_add_pc);
else {
OS << char(dwarf::DW_LNS_advance_pc);
MCObjectWriter::EncodeULEB128(AddrDelta, OS);
encodeULEB128(AddrDelta, OS);
}
OS << char(dwarf::DW_LNS_extended_op);
OS << char(1);
@ -376,7 +377,7 @@ void MCDwarfLineAddr::Encode(int64_t LineDelta, uint64_t AddrDelta,
// it with DW_LNS_advance_line.
if (Temp >= DWARF2_LINE_RANGE) {
OS << char(dwarf::DW_LNS_advance_line);
MCObjectWriter::EncodeSLEB128(LineDelta, OS);
encodeSLEB128(LineDelta, OS);
LineDelta = 0;
Temp = 0 - DWARF2_LINE_BASE;
@ -412,7 +413,7 @@ void MCDwarfLineAddr::Encode(int64_t LineDelta, uint64_t AddrDelta,
// Otherwise use DW_LNS_advance_pc.
OS << char(dwarf::DW_LNS_advance_pc);
MCObjectWriter::EncodeULEB128(AddrDelta, OS);
encodeULEB128(AddrDelta, OS);
if (NeedCopy)
OS << char(dwarf::DW_LNS_copy);

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@ -17,40 +17,6 @@ using namespace llvm;
MCObjectWriter::~MCObjectWriter() {
}
/// Utility function to encode a SLEB128 value.
void MCObjectWriter::EncodeSLEB128(int64_t Value, raw_ostream &OS) {
bool More;
do {
uint8_t Byte = Value & 0x7f;
// NOTE: this assumes that this signed shift is an arithmetic right shift.
Value >>= 7;
More = !((((Value == 0 ) && ((Byte & 0x40) == 0)) ||
((Value == -1) && ((Byte & 0x40) != 0))));
if (More)
Byte |= 0x80; // Mark this byte that that more bytes will follow.
OS << char(Byte);
} while (More);
}
/// Utility function to encode a ULEB128 value.
void MCObjectWriter::EncodeULEB128(uint64_t Value, raw_ostream &OS,
unsigned Padding) {
do {
uint8_t Byte = Value & 0x7f;
Value >>= 7;
if (Value != 0 || Padding != 0)
Byte |= 0x80; // Mark this byte that that more bytes will follow.
OS << char(Byte);
} while (Value != 0);
// Pad with 0x80 and emit a null byte at the end.
if (Padding != 0) {
for (; Padding != 1; --Padding)
OS << '\x80';
OS << '\x00';
}
}
bool
MCObjectWriter::IsSymbolRefDifferenceFullyResolved(const MCAssembler &Asm,
const MCSymbolRefExpr *A,

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@ -15,6 +15,7 @@
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/LEB128.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Twine.h"
#include <cstdlib>
@ -94,7 +95,7 @@ void MCStreamer::EmitULEB128IntValue(uint64_t Value, unsigned AddrSpace,
unsigned Padding) {
SmallString<128> Tmp;
raw_svector_ostream OSE(Tmp);
MCObjectWriter::EncodeULEB128(Value, OSE, Padding);
encodeULEB128(Value, OSE, Padding);
EmitBytes(OSE.str(), AddrSpace);
}
@ -103,7 +104,7 @@ void MCStreamer::EmitULEB128IntValue(uint64_t Value, unsigned AddrSpace,
void MCStreamer::EmitSLEB128IntValue(int64_t Value, unsigned AddrSpace) {
SmallString<128> Tmp;
raw_svector_ostream OSE(Tmp);
MCObjectWriter::EncodeSLEB128(Value, OSE);
encodeSLEB128(Value, OSE);
EmitBytes(OSE.str(), AddrSpace);
}