llvm/tools/llvm-mc/llvm-mc.cpp
Rafael Espindola 2600a677c9 Don't pass the code model to MC
I was surprised to see the code model being passed to MC. After all,
it assembles code, it doesn't create it.

The one place it is used is in the expansion of .cfi directives to
handle .eh_frame being more that 2gb away from the code.

As far as I can tell, gnu assembler doesn't even have an option to
enable this. Compiling a c file with gcc -mcmodel=large produces a
regular looking .eh_frame. This is probably because in practice linker
parse and recreate .eh_frames.

In llvm this is used because the JIT can place the code and .eh_frame
very far apart. Ideally we would fix the jit and delete this
option. This is hard.

Apart from confusion another problem with the current interface is
that most callers pass CodeModel::Default, which is bad since MC has
no way to map it to the target default if it actually needed to.

This patch then replaces the argument with a boolean with a default
value. The vast majority of users don't ever need to look at it. In
fact, only CodeGen and llvm-mc use it and llvm-mc just to enable more
testing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@309884 91177308-0d34-0410-b5e6-96231b3b80d8
2017-08-02 20:32:26 +00:00

628 lines
21 KiB
C++

//===-- llvm-mc.cpp - Machine Code Hacking Driver ---------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This utility is a simple driver that allows command line hacking on machine
// code.
//
//===----------------------------------------------------------------------===//
#include "Disassembler.h"
#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCInstPrinter.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCParser/AsmLexer.h"
#include "llvm/MC/MCParser/MCTargetAsmParser.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCTargetOptionsCommandFlags.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compression.h"
#include "llvm/Support/FileUtilities.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/PrettyStackTrace.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Support/ToolOutputFile.h"
using namespace llvm;
static cl::opt<std::string>
InputFilename(cl::Positional, cl::desc("<input file>"), cl::init("-"));
static cl::opt<std::string>
OutputFilename("o", cl::desc("Output filename"),
cl::value_desc("filename"));
static cl::opt<bool>
ShowEncoding("show-encoding", cl::desc("Show instruction encodings"));
static cl::opt<bool> RelaxELFRel(
"relax-relocations", cl::init(true),
cl::desc("Emit R_X86_64_GOTPCRELX instead of R_X86_64_GOTPCREL"));
static cl::opt<DebugCompressionType> CompressDebugSections(
"compress-debug-sections", cl::ValueOptional,
cl::init(DebugCompressionType::None),
cl::desc("Choose DWARF debug sections compression:"),
cl::values(clEnumValN(DebugCompressionType::None, "none", "No compression"),
clEnumValN(DebugCompressionType::Z, "zlib",
"Use zlib compression"),
clEnumValN(DebugCompressionType::GNU, "zlib-gnu",
"Use zlib-gnu compression (deprecated)")));
static cl::opt<bool>
ShowInst("show-inst", cl::desc("Show internal instruction representation"));
static cl::opt<bool>
ShowInstOperands("show-inst-operands",
cl::desc("Show instructions operands as parsed"));
static cl::opt<unsigned>
OutputAsmVariant("output-asm-variant",
cl::desc("Syntax variant to use for output printing"));
static cl::opt<bool>
PrintImmHex("print-imm-hex", cl::init(false),
cl::desc("Prefer hex format for immediate values"));
static cl::list<std::string>
DefineSymbol("defsym", cl::desc("Defines a symbol to be an integer constant"));
static cl::opt<bool>
PreserveComments("preserve-comments",
cl::desc("Preserve Comments in outputted assembly"));
enum OutputFileType {
OFT_Null,
OFT_AssemblyFile,
OFT_ObjectFile
};
static cl::opt<OutputFileType>
FileType("filetype", cl::init(OFT_AssemblyFile),
cl::desc("Choose an output file type:"),
cl::values(
clEnumValN(OFT_AssemblyFile, "asm",
"Emit an assembly ('.s') file"),
clEnumValN(OFT_Null, "null",
"Don't emit anything (for timing purposes)"),
clEnumValN(OFT_ObjectFile, "obj",
"Emit a native object ('.o') file")));
static cl::list<std::string>
IncludeDirs("I", cl::desc("Directory of include files"),
cl::value_desc("directory"), cl::Prefix);
static cl::opt<std::string>
ArchName("arch", cl::desc("Target arch to assemble for, "
"see -version for available targets"));
static cl::opt<std::string>
TripleName("triple", cl::desc("Target triple to assemble for, "
"see -version for available targets"));
static cl::opt<std::string>
MCPU("mcpu",
cl::desc("Target a specific cpu type (-mcpu=help for details)"),
cl::value_desc("cpu-name"),
cl::init(""));
static cl::list<std::string>
MAttrs("mattr",
cl::CommaSeparated,
cl::desc("Target specific attributes (-mattr=help for details)"),
cl::value_desc("a1,+a2,-a3,..."));
static cl::opt<bool> PIC("position-independent",
cl::desc("Position independent"), cl::init(false));
static cl::opt<bool>
LargeCodeModel("large-code-model",
cl::desc("Create cfi directives that assume the code might "
"be more than 2gb away"));
static cl::opt<bool>
NoInitialTextSection("n", cl::desc("Don't assume assembly file starts "
"in the text section"));
static cl::opt<bool>
GenDwarfForAssembly("g", cl::desc("Generate dwarf debugging info for assembly "
"source files"));
static cl::opt<std::string>
DebugCompilationDir("fdebug-compilation-dir",
cl::desc("Specifies the debug info's compilation dir"));
static cl::opt<std::string>
MainFileName("main-file-name",
cl::desc("Specifies the name we should consider the input file"));
static cl::opt<bool> SaveTempLabels("save-temp-labels",
cl::desc("Don't discard temporary labels"));
static cl::opt<bool> NoExecStack("no-exec-stack",
cl::desc("File doesn't need an exec stack"));
enum ActionType {
AC_AsLex,
AC_Assemble,
AC_Disassemble,
AC_MDisassemble,
};
static cl::opt<ActionType>
Action(cl::desc("Action to perform:"),
cl::init(AC_Assemble),
cl::values(clEnumValN(AC_AsLex, "as-lex",
"Lex tokens from a .s file"),
clEnumValN(AC_Assemble, "assemble",
"Assemble a .s file (default)"),
clEnumValN(AC_Disassemble, "disassemble",
"Disassemble strings of hex bytes"),
clEnumValN(AC_MDisassemble, "mdis",
"Marked up disassembly of strings of hex bytes")));
static const Target *GetTarget(const char *ProgName) {
// Figure out the target triple.
if (TripleName.empty())
TripleName = sys::getDefaultTargetTriple();
Triple TheTriple(Triple::normalize(TripleName));
// Get the target specific parser.
std::string Error;
const Target *TheTarget = TargetRegistry::lookupTarget(ArchName, TheTriple,
Error);
if (!TheTarget) {
errs() << ProgName << ": " << Error;
return nullptr;
}
// Update the triple name and return the found target.
TripleName = TheTriple.getTriple();
return TheTarget;
}
static std::unique_ptr<tool_output_file> GetOutputStream() {
if (OutputFilename == "")
OutputFilename = "-";
std::error_code EC;
auto Out = llvm::make_unique<tool_output_file>(OutputFilename, EC,
sys::fs::F_None);
if (EC) {
errs() << EC.message() << '\n';
return nullptr;
}
return Out;
}
static std::string DwarfDebugFlags;
static void setDwarfDebugFlags(int argc, char **argv) {
if (!getenv("RC_DEBUG_OPTIONS"))
return;
for (int i = 0; i < argc; i++) {
DwarfDebugFlags += argv[i];
if (i + 1 < argc)
DwarfDebugFlags += " ";
}
}
static std::string DwarfDebugProducer;
static void setDwarfDebugProducer() {
if(!getenv("DEBUG_PRODUCER"))
return;
DwarfDebugProducer += getenv("DEBUG_PRODUCER");
}
static int AsLexInput(SourceMgr &SrcMgr, MCAsmInfo &MAI,
raw_ostream &OS) {
AsmLexer Lexer(MAI);
Lexer.setBuffer(SrcMgr.getMemoryBuffer(SrcMgr.getMainFileID())->getBuffer());
bool Error = false;
while (Lexer.Lex().isNot(AsmToken::Eof)) {
const AsmToken &Tok = Lexer.getTok();
switch (Tok.getKind()) {
default:
SrcMgr.PrintMessage(Lexer.getLoc(), SourceMgr::DK_Warning,
"unknown token");
Error = true;
break;
case AsmToken::Error:
Error = true; // error already printed.
break;
case AsmToken::Identifier:
OS << "identifier: " << Lexer.getTok().getString();
break;
case AsmToken::Integer:
OS << "int: " << Lexer.getTok().getString();
break;
case AsmToken::Real:
OS << "real: " << Lexer.getTok().getString();
break;
case AsmToken::String:
OS << "string: " << Lexer.getTok().getString();
break;
case AsmToken::Amp: OS << "Amp"; break;
case AsmToken::AmpAmp: OS << "AmpAmp"; break;
case AsmToken::At: OS << "At"; break;
case AsmToken::Caret: OS << "Caret"; break;
case AsmToken::Colon: OS << "Colon"; break;
case AsmToken::Comma: OS << "Comma"; break;
case AsmToken::Dollar: OS << "Dollar"; break;
case AsmToken::Dot: OS << "Dot"; break;
case AsmToken::EndOfStatement: OS << "EndOfStatement"; break;
case AsmToken::Eof: OS << "Eof"; break;
case AsmToken::Equal: OS << "Equal"; break;
case AsmToken::EqualEqual: OS << "EqualEqual"; break;
case AsmToken::Exclaim: OS << "Exclaim"; break;
case AsmToken::ExclaimEqual: OS << "ExclaimEqual"; break;
case AsmToken::Greater: OS << "Greater"; break;
case AsmToken::GreaterEqual: OS << "GreaterEqual"; break;
case AsmToken::GreaterGreater: OS << "GreaterGreater"; break;
case AsmToken::Hash: OS << "Hash"; break;
case AsmToken::LBrac: OS << "LBrac"; break;
case AsmToken::LCurly: OS << "LCurly"; break;
case AsmToken::LParen: OS << "LParen"; break;
case AsmToken::Less: OS << "Less"; break;
case AsmToken::LessEqual: OS << "LessEqual"; break;
case AsmToken::LessGreater: OS << "LessGreater"; break;
case AsmToken::LessLess: OS << "LessLess"; break;
case AsmToken::Minus: OS << "Minus"; break;
case AsmToken::Percent: OS << "Percent"; break;
case AsmToken::Pipe: OS << "Pipe"; break;
case AsmToken::PipePipe: OS << "PipePipe"; break;
case AsmToken::Plus: OS << "Plus"; break;
case AsmToken::RBrac: OS << "RBrac"; break;
case AsmToken::RCurly: OS << "RCurly"; break;
case AsmToken::RParen: OS << "RParen"; break;
case AsmToken::Slash: OS << "Slash"; break;
case AsmToken::Star: OS << "Star"; break;
case AsmToken::Tilde: OS << "Tilde"; break;
case AsmToken::PercentCall16:
OS << "PercentCall16";
break;
case AsmToken::PercentCall_Hi:
OS << "PercentCall_Hi";
break;
case AsmToken::PercentCall_Lo:
OS << "PercentCall_Lo";
break;
case AsmToken::PercentDtprel_Hi:
OS << "PercentDtprel_Hi";
break;
case AsmToken::PercentDtprel_Lo:
OS << "PercentDtprel_Lo";
break;
case AsmToken::PercentGot:
OS << "PercentGot";
break;
case AsmToken::PercentGot_Disp:
OS << "PercentGot_Disp";
break;
case AsmToken::PercentGot_Hi:
OS << "PercentGot_Hi";
break;
case AsmToken::PercentGot_Lo:
OS << "PercentGot_Lo";
break;
case AsmToken::PercentGot_Ofst:
OS << "PercentGot_Ofst";
break;
case AsmToken::PercentGot_Page:
OS << "PercentGot_Page";
break;
case AsmToken::PercentGottprel:
OS << "PercentGottprel";
break;
case AsmToken::PercentGp_Rel:
OS << "PercentGp_Rel";
break;
case AsmToken::PercentHi:
OS << "PercentHi";
break;
case AsmToken::PercentHigher:
OS << "PercentHigher";
break;
case AsmToken::PercentHighest:
OS << "PercentHighest";
break;
case AsmToken::PercentLo:
OS << "PercentLo";
break;
case AsmToken::PercentNeg:
OS << "PercentNeg";
break;
case AsmToken::PercentPcrel_Hi:
OS << "PercentPcrel_Hi";
break;
case AsmToken::PercentPcrel_Lo:
OS << "PercentPcrel_Lo";
break;
case AsmToken::PercentTlsgd:
OS << "PercentTlsgd";
break;
case AsmToken::PercentTlsldm:
OS << "PercentTlsldm";
break;
case AsmToken::PercentTprel_Hi:
OS << "PercentTprel_Hi";
break;
case AsmToken::PercentTprel_Lo:
OS << "PercentTprel_Lo";
break;
}
// Print the token string.
OS << " (\"";
OS.write_escaped(Tok.getString());
OS << "\")\n";
}
return Error;
}
static int fillCommandLineSymbols(MCAsmParser &Parser) {
for (auto &I: DefineSymbol) {
auto Pair = StringRef(I).split('=');
auto Sym = Pair.first;
auto Val = Pair.second;
if (Sym.empty() || Val.empty()) {
errs() << "error: defsym must be of the form: sym=value: " << I << "\n";
return 1;
}
int64_t Value;
if (Val.getAsInteger(0, Value)) {
errs() << "error: Value is not an integer: " << Val << "\n";
return 1;
}
Parser.getContext().setSymbolValue(Parser.getStreamer(), Sym, Value);
}
return 0;
}
static int AssembleInput(const char *ProgName, const Target *TheTarget,
SourceMgr &SrcMgr, MCContext &Ctx, MCStreamer &Str,
MCAsmInfo &MAI, MCSubtargetInfo &STI,
MCInstrInfo &MCII, MCTargetOptions &MCOptions) {
std::unique_ptr<MCAsmParser> Parser(
createMCAsmParser(SrcMgr, Ctx, Str, MAI));
std::unique_ptr<MCTargetAsmParser> TAP(
TheTarget->createMCAsmParser(STI, *Parser, MCII, MCOptions));
if (!TAP) {
errs() << ProgName
<< ": error: this target does not support assembly parsing.\n";
return 1;
}
int SymbolResult = fillCommandLineSymbols(*Parser);
if(SymbolResult)
return SymbolResult;
Parser->setShowParsedOperands(ShowInstOperands);
Parser->setTargetParser(*TAP);
int Res = Parser->Run(NoInitialTextSection);
return Res;
}
int main(int argc, char **argv) {
// Print a stack trace if we signal out.
sys::PrintStackTraceOnErrorSignal(argv[0]);
PrettyStackTraceProgram X(argc, argv);
llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
// Initialize targets and assembly printers/parsers.
llvm::InitializeAllTargetInfos();
llvm::InitializeAllTargetMCs();
llvm::InitializeAllAsmParsers();
llvm::InitializeAllDisassemblers();
// Register the target printer for --version.
cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
cl::ParseCommandLineOptions(argc, argv, "llvm machine code playground\n");
MCTargetOptions MCOptions = InitMCTargetOptionsFromFlags();
TripleName = Triple::normalize(TripleName);
setDwarfDebugFlags(argc, argv);
setDwarfDebugProducer();
const char *ProgName = argv[0];
const Target *TheTarget = GetTarget(ProgName);
if (!TheTarget)
return 1;
// Now that GetTarget() has (potentially) replaced TripleName, it's safe to
// construct the Triple object.
Triple TheTriple(TripleName);
ErrorOr<std::unique_ptr<MemoryBuffer>> BufferPtr =
MemoryBuffer::getFileOrSTDIN(InputFilename);
if (std::error_code EC = BufferPtr.getError()) {
errs() << InputFilename << ": " << EC.message() << '\n';
return 1;
}
MemoryBuffer *Buffer = BufferPtr->get();
SourceMgr SrcMgr;
// Tell SrcMgr about this buffer, which is what the parser will pick up.
SrcMgr.AddNewSourceBuffer(std::move(*BufferPtr), SMLoc());
// Record the location of the include directories so that the lexer can find
// it later.
SrcMgr.setIncludeDirs(IncludeDirs);
std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TripleName));
assert(MRI && "Unable to create target register info!");
std::unique_ptr<MCAsmInfo> MAI(TheTarget->createMCAsmInfo(*MRI, TripleName));
assert(MAI && "Unable to create target asm info!");
MAI->setRelaxELFRelocations(RelaxELFRel);
if (CompressDebugSections != DebugCompressionType::None) {
if (!zlib::isAvailable()) {
errs() << ProgName
<< ": build tools with zlib to enable -compress-debug-sections";
return 1;
}
MAI->setCompressDebugSections(CompressDebugSections);
}
MAI->setPreserveAsmComments(PreserveComments);
// FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
// MCObjectFileInfo needs a MCContext reference in order to initialize itself.
MCObjectFileInfo MOFI;
MCContext Ctx(MAI.get(), MRI.get(), &MOFI, &SrcMgr);
MOFI.InitMCObjectFileInfo(TheTriple, PIC, Ctx, LargeCodeModel);
if (SaveTempLabels)
Ctx.setAllowTemporaryLabels(false);
Ctx.setGenDwarfForAssembly(GenDwarfForAssembly);
// Default to 4 for dwarf version.
unsigned DwarfVersion = MCOptions.DwarfVersion ? MCOptions.DwarfVersion : 4;
if (DwarfVersion < 2 || DwarfVersion > 5) {
errs() << ProgName << ": Dwarf version " << DwarfVersion
<< " is not supported." << '\n';
return 1;
}
Ctx.setDwarfVersion(DwarfVersion);
if (!DwarfDebugFlags.empty())
Ctx.setDwarfDebugFlags(StringRef(DwarfDebugFlags));
if (!DwarfDebugProducer.empty())
Ctx.setDwarfDebugProducer(StringRef(DwarfDebugProducer));
if (!DebugCompilationDir.empty())
Ctx.setCompilationDir(DebugCompilationDir);
else {
// If no compilation dir is set, try to use the current directory.
SmallString<128> CWD;
if (!sys::fs::current_path(CWD))
Ctx.setCompilationDir(CWD);
}
if (!MainFileName.empty())
Ctx.setMainFileName(MainFileName);
// Package up features to be passed to target/subtarget
std::string FeaturesStr;
if (MAttrs.size()) {
SubtargetFeatures Features;
for (unsigned i = 0; i != MAttrs.size(); ++i)
Features.AddFeature(MAttrs[i]);
FeaturesStr = Features.getString();
}
std::unique_ptr<tool_output_file> Out = GetOutputStream();
if (!Out)
return 1;
std::unique_ptr<buffer_ostream> BOS;
raw_pwrite_stream *OS = &Out->os();
std::unique_ptr<MCStreamer> Str;
std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
std::unique_ptr<MCSubtargetInfo> STI(
TheTarget->createMCSubtargetInfo(TripleName, MCPU, FeaturesStr));
MCInstPrinter *IP = nullptr;
if (FileType == OFT_AssemblyFile) {
IP = TheTarget->createMCInstPrinter(Triple(TripleName), OutputAsmVariant,
*MAI, *MCII, *MRI);
if (!IP) {
errs()
<< "error: unable to create instruction printer for target triple '"
<< TheTriple.normalize() << "' with assembly variant "
<< OutputAsmVariant << ".\n";
return 1;
}
// Set the display preference for hex vs. decimal immediates.
IP->setPrintImmHex(PrintImmHex);
// Set up the AsmStreamer.
MCCodeEmitter *CE = nullptr;
MCAsmBackend *MAB = nullptr;
if (ShowEncoding) {
CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx);
MAB = TheTarget->createMCAsmBackend(*MRI, TripleName, MCPU, MCOptions);
}
auto FOut = llvm::make_unique<formatted_raw_ostream>(*OS);
Str.reset(TheTarget->createAsmStreamer(
Ctx, std::move(FOut), /*asmverbose*/ true,
/*useDwarfDirectory*/ true, IP, CE, MAB, ShowInst));
} else if (FileType == OFT_Null) {
Str.reset(TheTarget->createNullStreamer(Ctx));
} else {
assert(FileType == OFT_ObjectFile && "Invalid file type!");
// Don't waste memory on names of temp labels.
Ctx.setUseNamesOnTempLabels(false);
if (!Out->os().supportsSeeking()) {
BOS = make_unique<buffer_ostream>(Out->os());
OS = BOS.get();
}
MCCodeEmitter *CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx);
MCAsmBackend *MAB = TheTarget->createMCAsmBackend(*MRI, TripleName, MCPU,
MCOptions);
Str.reset(TheTarget->createMCObjectStreamer(
TheTriple, Ctx, *MAB, *OS, CE, *STI, MCOptions.MCRelaxAll,
MCOptions.MCIncrementalLinkerCompatible,
/*DWARFMustBeAtTheEnd*/ false));
if (NoExecStack)
Str->InitSections(true);
}
int Res = 1;
bool disassemble = false;
switch (Action) {
case AC_AsLex:
Res = AsLexInput(SrcMgr, *MAI, Out->os());
break;
case AC_Assemble:
Res = AssembleInput(ProgName, TheTarget, SrcMgr, Ctx, *Str, *MAI, *STI,
*MCII, MCOptions);
break;
case AC_MDisassemble:
assert(IP && "Expected assembly output");
IP->setUseMarkup(1);
disassemble = true;
break;
case AC_Disassemble:
disassemble = true;
break;
}
if (disassemble)
Res = Disassembler::disassemble(*TheTarget, TripleName, *STI, *Str,
*Buffer, SrcMgr, Out->os());
// Keep output if no errors.
if (Res == 0) Out->keep();
return Res;
}