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llvm-mirror/lib/MC/MCAsmStreamer.cpp
Chris Lattner 405e4a1d63 genericize MCAsmStreamer::EmitCodeAlignment to support other targets 
so that it doesn't break them when the code generator starts using it.

llvm-svn: 96966
2010-02-23 18:44:31 +00:00

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//===- lib/MC/MCAsmStreamer.cpp - Text Assembly Output --------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstPrinter.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/FormattedStream.h"
using namespace llvm;
namespace {
class MCAsmStreamer : public MCStreamer {
formatted_raw_ostream &OS;
const MCAsmInfo &MAI;
MCInstPrinter *InstPrinter;
MCCodeEmitter *Emitter;
SmallString<128> CommentToEmit;
raw_svector_ostream CommentStream;
unsigned IsLittleEndian : 1;
unsigned IsVerboseAsm : 1;
unsigned ShowInst : 1;
public:
MCAsmStreamer(MCContext &Context, formatted_raw_ostream &os,
const MCAsmInfo &mai,
bool isLittleEndian, bool isVerboseAsm, MCInstPrinter *printer,
MCCodeEmitter *emitter, bool showInst)
: MCStreamer(Context), OS(os), MAI(mai), InstPrinter(printer),
Emitter(emitter), CommentStream(CommentToEmit),
IsLittleEndian(isLittleEndian), IsVerboseAsm(isVerboseAsm),
ShowInst(showInst) {
if (InstPrinter && IsVerboseAsm)
InstPrinter->setCommentStream(CommentStream);
}
~MCAsmStreamer() {}
bool isLittleEndian() const { return IsLittleEndian; }
inline void EmitEOL() {
// If we don't have any comments, just emit a \n.
if (!IsVerboseAsm) {
OS << '\n';
return;
}
EmitCommentsAndEOL();
}
void EmitCommentsAndEOL();
/// isVerboseAsm - Return true if this streamer supports verbose assembly at
/// all.
virtual bool isVerboseAsm() const { return IsVerboseAsm; }
/// AddComment - Add a comment that can be emitted to the generated .s
/// file if applicable as a QoI issue to make the output of the compiler
/// more readable. This only affects the MCAsmStreamer, and only when
/// verbose assembly output is enabled.
virtual void AddComment(const Twine &T);
/// AddEncodingComment - Add a comment showing the encoding of an instruction.
virtual void AddEncodingComment(const MCInst &Inst);
/// GetCommentOS - Return a raw_ostream that comments can be written to.
/// Unlike AddComment, you are required to terminate comments with \n if you
/// use this method.
virtual raw_ostream &GetCommentOS() {
if (!IsVerboseAsm)
return nulls(); // Discard comments unless in verbose asm mode.
return CommentStream;
}
/// AddBlankLine - Emit a blank line to a .s file to pretty it up.
virtual void AddBlankLine() {
EmitEOL();
}
/// @name MCStreamer Interface
/// @{
virtual void SwitchSection(const MCSection *Section);
virtual void EmitLabel(MCSymbol *Symbol);
virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue);
virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value);
virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
unsigned ByteAlignment);
/// EmitLocalCommonSymbol - Emit a local common (.lcomm) symbol.
///
/// @param Symbol - The common symbol to emit.
/// @param Size - The size of the common symbol.
virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size);
virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
unsigned Size = 0, unsigned ByteAlignment = 0);
virtual void EmitBytes(StringRef Data, unsigned AddrSpace);
virtual void EmitValue(const MCExpr *Value, unsigned Size,unsigned AddrSpace);
virtual void EmitIntValue(uint64_t Value, unsigned Size, unsigned AddrSpace);
virtual void EmitGPRel32Value(const MCExpr *Value);
virtual void EmitFill(uint64_t NumBytes, uint8_t FillValue,
unsigned AddrSpace);
virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
unsigned ValueSize = 1,
unsigned MaxBytesToEmit = 0);
virtual void EmitCodeAlignment(unsigned ByteAlignment,
unsigned MaxBytesToEmit = 0);
virtual void EmitValueToOffset(const MCExpr *Offset,
unsigned char Value = 0);
virtual void EmitFileDirective(StringRef Filename);
virtual void EmitDwarfFileDirective(unsigned FileNo, StringRef Filename);
virtual void EmitInstruction(const MCInst &Inst);
virtual void Finish();
/// @}
};
} // end anonymous namespace.
/// AddComment - Add a comment that can be emitted to the generated .s
/// file if applicable as a QoI issue to make the output of the compiler
/// more readable. This only affects the MCAsmStreamer, and only when
/// verbose assembly output is enabled.
void MCAsmStreamer::AddComment(const Twine &T) {
if (!IsVerboseAsm) return;
// Make sure that CommentStream is flushed.
CommentStream.flush();
T.toVector(CommentToEmit);
// Each comment goes on its own line.
CommentToEmit.push_back('\n');
// Tell the comment stream that the vector changed underneath it.
CommentStream.resync();
}
void MCAsmStreamer::EmitCommentsAndEOL() {
if (CommentToEmit.empty() && CommentStream.GetNumBytesInBuffer() == 0) {
OS << '\n';
return;
}
CommentStream.flush();
StringRef Comments = CommentToEmit.str();
assert(Comments.back() == '\n' &&
"Comment array not newline terminated");
do {
// Emit a line of comments.
OS.PadToColumn(MAI.getCommentColumn());
size_t Position = Comments.find('\n');
OS << MAI.getCommentString() << ' ' << Comments.substr(0, Position) << '\n';
Comments = Comments.substr(Position+1);
} while (!Comments.empty());
CommentToEmit.clear();
// Tell the comment stream that the vector changed underneath it.
CommentStream.resync();
}
static inline int64_t truncateToSize(int64_t Value, unsigned Bytes) {
assert(Bytes && "Invalid size!");
return Value & ((uint64_t) (int64_t) -1 >> (64 - Bytes * 8));
}
void MCAsmStreamer::SwitchSection(const MCSection *Section) {
assert(Section && "Cannot switch to a null section!");
if (Section != CurSection) {
CurSection = Section;
Section->PrintSwitchToSection(MAI, OS);
}
}
void MCAsmStreamer::EmitLabel(MCSymbol *Symbol) {
assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
assert(CurSection && "Cannot emit before setting section!");
OS << *Symbol << ":";
EmitEOL();
Symbol->setSection(*CurSection);
}
void MCAsmStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
switch (Flag) {
default: assert(0 && "Invalid flag!");
case MCAF_SubsectionsViaSymbols: OS << ".subsections_via_symbols"; break;
}
EmitEOL();
}
void MCAsmStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
// Only absolute symbols can be redefined.
assert((Symbol->isUndefined() || Symbol->isAbsolute()) &&
"Cannot define a symbol twice!");
OS << *Symbol << " = " << *Value;
EmitEOL();
// FIXME: Lift context changes into super class.
// FIXME: Set associated section.
Symbol->setValue(Value);
}
void MCAsmStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
MCSymbolAttr Attribute) {
switch (Attribute) {
case MCSA_Invalid: assert(0 && "Invalid symbol attribute");
case MCSA_ELF_TypeFunction: /// .type _foo, STT_FUNC # aka @function
case MCSA_ELF_TypeIndFunction: /// .type _foo, STT_GNU_IFUNC
case MCSA_ELF_TypeObject: /// .type _foo, STT_OBJECT # aka @object
case MCSA_ELF_TypeTLS: /// .type _foo, STT_TLS # aka @tls_object
case MCSA_ELF_TypeCommon: /// .type _foo, STT_COMMON # aka @common
case MCSA_ELF_TypeNoType: /// .type _foo, STT_NOTYPE # aka @notype
assert(MAI.hasDotTypeDotSizeDirective() && "Symbol Attr not supported");
OS << "\t.type\t" << *Symbol << ','
<< ((MAI.getCommentString()[0] != '@') ? '@' : '%');
switch (Attribute) {
default: assert(0 && "Unknown ELF .type");
case MCSA_ELF_TypeFunction: OS << "function"; break;
case MCSA_ELF_TypeIndFunction: OS << "gnu_indirect_function"; break;
case MCSA_ELF_TypeObject: OS << "object"; break;
case MCSA_ELF_TypeTLS: OS << "tls_object"; break;
case MCSA_ELF_TypeCommon: OS << "common"; break;
case MCSA_ELF_TypeNoType: OS << "no_type"; break;
}
EmitEOL();
return;
case MCSA_Global: // .globl/.global
OS << MAI.getGlobalDirective();
break;
case MCSA_Hidden: OS << ".hidden "; break;
case MCSA_IndirectSymbol: OS << ".indirect_symbol "; break;
case MCSA_Internal: OS << ".internal "; break;
case MCSA_LazyReference: OS << ".lazy_reference "; break;
case MCSA_Local: OS << ".local "; break;
case MCSA_NoDeadStrip: OS << ".no_dead_strip "; break;
case MCSA_PrivateExtern: OS << ".private_extern "; break;
case MCSA_Protected: OS << ".protected "; break;
case MCSA_Reference: OS << ".reference "; break;
case MCSA_Weak: OS << ".weak "; break;
case MCSA_WeakDefinition: OS << ".weak_definition "; break;
// .weak_reference
case MCSA_WeakReference: OS << MAI.getWeakRefDirective(); break;
}
OS << *Symbol;
EmitEOL();
}
void MCAsmStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
OS << ".desc" << ' ' << *Symbol << ',' << DescValue;
EmitEOL();
}
void MCAsmStreamer::EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
assert(MAI.hasDotTypeDotSizeDirective());
OS << "\t.size\t" << *Symbol << ", " << *Value << '\n';
}
void MCAsmStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
unsigned ByteAlignment) {
OS << "\t.comm\t" << *Symbol << ',' << Size;
if (ByteAlignment != 0) {
if (MAI.getCOMMDirectiveAlignmentIsInBytes())
OS << ',' << ByteAlignment;
else
OS << ',' << Log2_32(ByteAlignment);
}
EmitEOL();
}
/// EmitLocalCommonSymbol - Emit a local common (.lcomm) symbol.
///
/// @param Symbol - The common symbol to emit.
/// @param Size - The size of the common symbol.
void MCAsmStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) {
assert(MAI.hasLCOMMDirective() && "Doesn't have .lcomm, can't emit it!");
OS << "\t.lcomm\t" << *Symbol << ',' << Size;
EmitEOL();
}
void MCAsmStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
unsigned Size, unsigned ByteAlignment) {
// Note: a .zerofill directive does not switch sections.
OS << ".zerofill ";
// This is a mach-o specific directive.
const MCSectionMachO *MOSection = ((const MCSectionMachO*)Section);
OS << MOSection->getSegmentName() << "," << MOSection->getSectionName();
if (Symbol != NULL) {
OS << ',' << *Symbol << ',' << Size;
if (ByteAlignment != 0)
OS << ',' << Log2_32(ByteAlignment);
}
EmitEOL();
}
static inline char toOctal(int X) { return (X&7)+'0'; }
static void PrintQuotedString(StringRef Data, raw_ostream &OS) {
OS << '"';
for (unsigned i = 0, e = Data.size(); i != e; ++i) {
unsigned char C = Data[i];
if (C == '"' || C == '\\') {
OS << '\\' << (char)C;
continue;
}
if (isprint((unsigned char)C)) {
OS << (char)C;
continue;
}
switch (C) {
case '\b': OS << "\\b"; break;
case '\f': OS << "\\f"; break;
case '\n': OS << "\\n"; break;
case '\r': OS << "\\r"; break;
case '\t': OS << "\\t"; break;
default:
OS << '\\';
OS << toOctal(C >> 6);
OS << toOctal(C >> 3);
OS << toOctal(C >> 0);
break;
}
}
OS << '"';
}
void MCAsmStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
assert(CurSection && "Cannot emit contents before setting section!");
if (Data.empty()) return;
if (Data.size() == 1) {
OS << MAI.getData8bitsDirective(AddrSpace);
OS << (unsigned)(unsigned char)Data[0];
EmitEOL();
return;
}
// If the data ends with 0 and the target supports .asciz, use it, otherwise
// use .ascii
if (MAI.getAscizDirective() && Data.back() == 0) {
OS << MAI.getAscizDirective();
Data = Data.substr(0, Data.size()-1);
} else {
OS << MAI.getAsciiDirective();
}
OS << ' ';
PrintQuotedString(Data, OS);
EmitEOL();
}
/// EmitIntValue - Special case of EmitValue that avoids the client having
/// to pass in a MCExpr for constant integers.
void MCAsmStreamer::EmitIntValue(uint64_t Value, unsigned Size,
unsigned AddrSpace) {
assert(CurSection && "Cannot emit contents before setting section!");
const char *Directive = 0;
switch (Size) {
default: break;
case 1: Directive = MAI.getData8bitsDirective(AddrSpace); break;
case 2: Directive = MAI.getData16bitsDirective(AddrSpace); break;
case 4: Directive = MAI.getData32bitsDirective(AddrSpace); break;
case 8:
Directive = MAI.getData64bitsDirective(AddrSpace);
// If the target doesn't support 64-bit data, emit as two 32-bit halves.
if (Directive) break;
if (isLittleEndian()) {
EmitIntValue((uint32_t)(Value >> 0 ), 4, AddrSpace);
EmitIntValue((uint32_t)(Value >> 32), 4, AddrSpace);
} else {
EmitIntValue((uint32_t)(Value >> 32), 4, AddrSpace);
EmitIntValue((uint32_t)(Value >> 0 ), 4, AddrSpace);
}
return;
}
assert(Directive && "Invalid size for machine code value!");
OS << Directive << truncateToSize(Value, Size);
EmitEOL();
}
void MCAsmStreamer::EmitValue(const MCExpr *Value, unsigned Size,
unsigned AddrSpace) {
assert(CurSection && "Cannot emit contents before setting section!");
const char *Directive = 0;
switch (Size) {
default: break;
case 1: Directive = MAI.getData8bitsDirective(AddrSpace); break;
case 2: Directive = MAI.getData16bitsDirective(AddrSpace); break;
case 4: Directive = MAI.getData32bitsDirective(AddrSpace); break;
case 8: Directive = MAI.getData64bitsDirective(AddrSpace); break;
}
assert(Directive && "Invalid size for machine code value!");
OS << Directive << *Value;
EmitEOL();
}
void MCAsmStreamer::EmitGPRel32Value(const MCExpr *Value) {
assert(MAI.getGPRel32Directive() != 0);
OS << MAI.getGPRel32Directive() << *Value;
EmitEOL();
}
/// EmitFill - Emit NumBytes bytes worth of the value specified by
/// FillValue. This implements directives such as '.space'.
void MCAsmStreamer::EmitFill(uint64_t NumBytes, uint8_t FillValue,
unsigned AddrSpace) {
if (NumBytes == 0) return;
if (AddrSpace == 0)
if (const char *ZeroDirective = MAI.getZeroDirective()) {
OS << ZeroDirective << NumBytes;
if (FillValue != 0)
OS << ',' << (int)FillValue;
EmitEOL();
return;
}
// Emit a byte at a time.
MCStreamer::EmitFill(NumBytes, FillValue, AddrSpace);
}
void MCAsmStreamer::EmitValueToAlignment(unsigned ByteAlignment, int64_t Value,
unsigned ValueSize,
unsigned MaxBytesToEmit) {
// Some assemblers don't support non-power of two alignments, so we always
// emit alignments as a power of two if possible.
if (isPowerOf2_32(ByteAlignment)) {
switch (ValueSize) {
default: llvm_unreachable("Invalid size for machine code value!");
case 1: OS << MAI.getAlignDirective(); break;
// FIXME: use MAI for this!
case 2: OS << ".p2alignw "; break;
case 4: OS << ".p2alignl "; break;
case 8: llvm_unreachable("Unsupported alignment size!");
}
if (MAI.getAlignmentIsInBytes())
OS << ByteAlignment;
else
OS << Log2_32(ByteAlignment);
if (Value || MaxBytesToEmit) {
OS << ", 0x";
OS.write_hex(truncateToSize(Value, ValueSize));
if (MaxBytesToEmit)
OS << ", " << MaxBytesToEmit;
}
EmitEOL();
return;
}
// Non-power of two alignment. This is not widely supported by assemblers.
// FIXME: Parameterize this based on MAI.
switch (ValueSize) {
default: llvm_unreachable("Invalid size for machine code value!");
case 1: OS << ".balign"; break;
case 2: OS << ".balignw"; break;
case 4: OS << ".balignl"; break;
case 8: llvm_unreachable("Unsupported alignment size!");
}
OS << ' ' << ByteAlignment;
OS << ", " << truncateToSize(Value, ValueSize);
if (MaxBytesToEmit)
OS << ", " << MaxBytesToEmit;
EmitEOL();
}
void MCAsmStreamer::EmitCodeAlignment(unsigned ByteAlignment,
unsigned MaxBytesToEmit) {
// Emit with a text fill value.
EmitValueToAlignment(ByteAlignment, MAI.getTextAlignFillValue(),
1, MaxBytesToEmit);
}
void MCAsmStreamer::EmitValueToOffset(const MCExpr *Offset,
unsigned char Value) {
// FIXME: Verify that Offset is associated with the current section.
OS << ".org " << *Offset << ", " << (unsigned) Value;
EmitEOL();
}
void MCAsmStreamer::EmitFileDirective(StringRef Filename) {
assert(MAI.hasSingleParameterDotFile());
OS << "\t.file\t";
PrintQuotedString(Filename, OS);
EmitEOL();
}
void MCAsmStreamer::EmitDwarfFileDirective(unsigned FileNo, StringRef Filename){
OS << "\t.file\t" << FileNo << ' ';
PrintQuotedString(Filename, OS);
EmitEOL();
}
void MCAsmStreamer::AddEncodingComment(const MCInst &Inst) {
raw_ostream &OS = GetCommentOS();
SmallString<256> Code;
SmallVector<MCFixup, 4> Fixups;
raw_svector_ostream VecOS(Code);
Emitter->EncodeInstruction(Inst, VecOS, Fixups);
VecOS.flush();
// If we are showing fixups, create symbolic markers in the encoded
// representation. We do this by making a per-bit map to the fixup item index,
// then trying to display it as nicely as possible.
SmallVector<uint8_t, 64> FixupMap;
FixupMap.resize(Code.size() * 8);
for (unsigned i = 0, e = Code.size() * 8; i != e; ++i)
FixupMap[i] = 0;
for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
MCFixup &F = Fixups[i];
const MCFixupKindInfo &Info = Emitter->getFixupKindInfo(F.getKind());
for (unsigned j = 0; j != Info.TargetSize; ++j) {
unsigned Index = F.getOffset() * 8 + Info.TargetOffset + j;
assert(Index < Code.size() * 8 && "Invalid offset in fixup!");
FixupMap[Index] = 1 + i;
}
}
OS << "encoding: [";
for (unsigned i = 0, e = Code.size(); i != e; ++i) {
if (i)
OS << ',';
// See if all bits are the same map entry.
uint8_t MapEntry = FixupMap[i * 8 + 0];
for (unsigned j = 1; j != 8; ++j) {
if (FixupMap[i * 8 + j] == MapEntry)
continue;
MapEntry = uint8_t(~0U);
break;
}
if (MapEntry != uint8_t(~0U)) {
if (MapEntry == 0) {
OS << format("0x%02x", uint8_t(Code[i]));
} else {
assert(Code[i] == 0 && "Encoder wrote into fixed up bit!");
OS << char('A' + MapEntry - 1);
}
} else {
// Otherwise, write out in binary.
OS << "0b";
for (unsigned j = 8; j--;) {
unsigned Bit = (Code[i] >> j) & 1;
if (uint8_t MapEntry = FixupMap[i * 8 + j]) {
assert(Bit == 0 && "Encoder wrote into fixed up bit!");
OS << char('A' + MapEntry - 1);
} else
OS << Bit;
}
}
}
OS << "]\n";
for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
MCFixup &F = Fixups[i];
const MCFixupKindInfo &Info = Emitter->getFixupKindInfo(F.getKind());
OS << " fixup " << char('A' + i) << " - " << "offset: " << F.getOffset()
<< ", value: " << *F.getValue() << ", kind: " << Info.Name << "\n";
}
}
void MCAsmStreamer::EmitInstruction(const MCInst &Inst) {
assert(CurSection && "Cannot emit contents before setting section!");
// Show the encoding in a comment if we have a code emitter.
if (Emitter)
AddEncodingComment(Inst);
// Show the MCInst if enabled.
if (ShowInst) {
raw_ostream &OS = GetCommentOS();
OS << "<MCInst #" << Inst.getOpcode();
StringRef InstName;
if (InstPrinter)
InstName = InstPrinter->getOpcodeName(Inst.getOpcode());
if (!InstName.empty())
OS << ' ' << InstName;
for (unsigned i = 0, e = Inst.getNumOperands(); i != e; ++i) {
OS << "\n ";
Inst.getOperand(i).print(OS, &MAI);
}
OS << ">\n";
}
// If we have an AsmPrinter, use that to print, otherwise dump the MCInst.
if (InstPrinter)
InstPrinter->printInst(&Inst);
else
Inst.print(OS, &MAI);
EmitEOL();
}
void MCAsmStreamer::Finish() {
OS.flush();
}
MCStreamer *llvm::createAsmStreamer(MCContext &Context,
formatted_raw_ostream &OS,
const MCAsmInfo &MAI, bool isLittleEndian,
bool isVerboseAsm, MCInstPrinter *IP,
MCCodeEmitter *CE, bool ShowInst) {
return new MCAsmStreamer(Context, OS, MAI, isLittleEndian, isVerboseAsm,
IP, CE, ShowInst);
}
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