llc.cpp
//===-- llc.cpp - Implement the LLVM Native Code Generator ----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This is the llc code generator driver. It provides a convenient
// command-line interface for generating native assembly-language code
// or C code, given LLVM bitcode.
//
//===----------------------------------------------------------------------===//
#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/PassManager.h"
#include "llvm/Pass.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Support/IRReader.h"
#include "llvm/CodeGen/LinkAllAsmWriterComponents.h"
#include "llvm/CodeGen/LinkAllCodegenComponents.h"
#include "llvm/MC/SubtargetFeature.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/PluginLoader.h"
#include "llvm/Support/PrettyStackTrace.h"
#include "llvm/Support/ToolOutputFile.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetMachine.h"
#include <memory>
using namespace llvm;
// General options for llc. Other pass-specific options are specified
// within the corresponding llc passes, and target-specific options
// and back-end code generation options are specified with the target machine.
//
static cl::opt<std::string>
InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
static cl::opt<std::string>
OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
// Determine optimization level.
static cl::opt<char>
OptLevel("O",
cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
"(default = '-O2')"),
cl::Prefix,
cl::ZeroOrMore,
cl::init(' '));
static cl::opt<std::string>
TargetTriple("mtriple", cl::desc("Override target triple for module"));
static cl::opt<std::string>
MArch("march", cl::desc("Architecture to generate code for (see --version)"));
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<Reloc::Model>
RelocModel("relocation-model",
cl::desc("Choose relocation model"),
cl::init(Reloc::Default),
cl::values(
clEnumValN(Reloc::Default, "default",
"Target default relocation model"),
clEnumValN(Reloc::Static, "static",
"Non-relocatable code"),
clEnumValN(Reloc::PIC_, "pic",
"Fully relocatable, position independent code"),
clEnumValN(Reloc::DynamicNoPIC, "dynamic-no-pic",
"Relocatable external references, non-relocatable code"),
clEnumValEnd));
static cl::opt<llvm::CodeModel::Model>
CMModel("code-model",
cl::desc("Choose code model"),
cl::init(CodeModel::Default),
cl::values(clEnumValN(CodeModel::Default, "default",
"Target default code model"),
clEnumValN(CodeModel::Small, "small",
"Small code model"),
clEnumValN(CodeModel::Kernel, "kernel",
"Kernel code model"),
clEnumValN(CodeModel::Medium, "medium",
"Medium code model"),
clEnumValN(CodeModel::Large, "large",
"Large code model"),
clEnumValEnd));
static cl::opt<bool>
RelaxAll("mc-relax-all",
cl::desc("When used with filetype=obj, "
"relax all fixups in the emitted object file"));
cl::opt<TargetMachine::CodeGenFileType>
FileType("filetype", cl::init(TargetMachine::CGFT_AssemblyFile),
cl::desc("Choose a file type (not all types are supported by all targets):"),
cl::values(
clEnumValN(TargetMachine::CGFT_AssemblyFile, "asm",
"Emit an assembly ('.s') file"),
clEnumValN(TargetMachine::CGFT_ObjectFile, "obj",
"Emit a native object ('.o') file [experimental]"),
clEnumValN(TargetMachine::CGFT_Null, "null",
"Emit nothing, for performance testing"),
clEnumValEnd));
cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
cl::desc("Do not verify input module"));
cl::opt<bool> DisableDotLoc("disable-dot-loc", cl::Hidden,
cl::desc("Do not use .loc entries"));
cl::opt<bool> DisableCFI("disable-cfi", cl::Hidden,
cl::desc("Do not use .cfi_* directives"));
cl::opt<bool> EnableDwarfDirectory("enable-dwarf-directory", cl::Hidden,
cl::desc("Use .file directives with an explicit directory."));
static cl::opt<bool>
DisableRedZone("disable-red-zone",
cl::desc("Do not emit code that uses the red zone."),
cl::init(false));
static cl::opt<bool>
EnableFPMAD("enable-fp-mad",
cl::desc("Enable less precise MAD instructions to be generated"),
cl::init(false));
static cl::opt<bool>
PrintCode("print-machineinstrs",
cl::desc("Print generated machine code"),
cl::init(false));
static cl::opt<bool>
DisableFPElim("disable-fp-elim",
cl::desc("Disable frame pointer elimination optimization"),
cl::init(false));
static cl::opt<bool>
DisableFPElimNonLeaf("disable-non-leaf-fp-elim",
cl::desc("Disable frame pointer elimination optimization for non-leaf funcs"),
cl::init(false));
static cl::opt<bool>
DisableExcessPrecision("disable-excess-fp-precision",
cl::desc("Disable optimizations that may increase FP precision"),
cl::init(false));
static cl::opt<bool>
EnableUnsafeFPMath("enable-unsafe-fp-math",
cl::desc("Enable optimizations that may decrease FP precision"),
cl::init(false));
static cl::opt<bool>
EnableNoInfsFPMath("enable-no-infs-fp-math",
cl::desc("Enable FP math optimizations that assume no +-Infs"),
cl::init(false));
static cl::opt<bool>
EnableNoNaNsFPMath("enable-no-nans-fp-math",
cl::desc("Enable FP math optimizations that assume no NaNs"),
cl::init(false));
static cl::opt<bool>
EnableHonorSignDependentRoundingFPMath("enable-sign-dependent-rounding-fp-math",
cl::Hidden,
cl::desc("Force codegen to assume rounding mode can change dynamically"),
cl::init(false));
static cl::opt<bool>
GenerateSoftFloatCalls("soft-float",
cl::desc("Generate software floating point library calls"),
cl::init(false));
static cl::opt<llvm::FloatABI::ABIType>
FloatABIForCalls("float-abi",
cl::desc("Choose float ABI type"),
cl::init(FloatABI::Default),
cl::values(
clEnumValN(FloatABI::Default, "default",
"Target default float ABI type"),
clEnumValN(FloatABI::Soft, "soft",
"Soft float ABI (implied by -soft-float)"),
clEnumValN(FloatABI::Hard, "hard",
"Hard float ABI (uses FP registers)"),
clEnumValEnd));
static cl::opt<bool>
DontPlaceZerosInBSS("nozero-initialized-in-bss",
cl::desc("Don't place zero-initialized symbols into bss section"),
cl::init(false));
static cl::opt<bool>
EnableGuaranteedTailCallOpt("tailcallopt",
cl::desc("Turn fastcc calls into tail calls by (potentially) changing ABI."),
cl::init(false));
static cl::opt<bool>
DisableTailCalls("disable-tail-calls",
cl::desc("Never emit tail calls"),
cl::init(false));
static cl::opt<unsigned>
OverrideStackAlignment("stack-alignment",
cl::desc("Override default stack alignment"),
cl::init(0));
static cl::opt<bool>
EnableRealignStack("realign-stack",
cl::desc("Realign stack if needed"),
cl::init(true));
static cl::opt<bool>
DisableSwitchTables(cl::Hidden, "disable-jump-tables",
cl::desc("Do not generate jump tables."),
cl::init(false));
static cl::opt<std::string>
TrapFuncName("trap-func", cl::Hidden,
cl::desc("Emit a call to trap function rather than a trap instruction"),
cl::init(""));
static cl::opt<bool>
EnablePIE("enable-pie",
cl::desc("Assume the creation of a position independent executable."),
cl::init(false));
static cl::opt<bool>
SegmentedStacks("segmented-stacks",
cl::desc("Use segmented stacks if possible."),
cl::init(false));
// GetFileNameRoot - Helper function to get the basename of a filename.
static inline std::string
GetFileNameRoot(const std::string &InputFilename) {
std::string IFN = InputFilename;
std::string outputFilename;
int Len = IFN.length();
if ((Len > 2) &&
IFN[Len-3] == '.' &&
((IFN[Len-2] == 'b' && IFN[Len-1] == 'c') ||
(IFN[Len-2] == 'l' && IFN[Len-1] == 'l'))) {
outputFilename = std::string(IFN.begin(), IFN.end()-3); // s/.bc/.s/
} else {
outputFilename = IFN;
}
return outputFilename;
}
static tool_output_file *GetOutputStream(const char *TargetName,
Triple::OSType OS,
const char *ProgName) {
// If we don't yet have an output filename, make one.
if (OutputFilename.empty()) {
if (InputFilename == "-")
OutputFilename = "-";
else {
OutputFilename = GetFileNameRoot(InputFilename);
switch (FileType) {
case TargetMachine::CGFT_AssemblyFile:
if (TargetName[0] == 'c') {
if (TargetName[1] == 0)
OutputFilename += ".cbe.c";
else if (TargetName[1] == 'p' && TargetName[2] == 'p')
OutputFilename += ".cpp";
else
OutputFilename += ".s";
} else
OutputFilename += ".s";
break;
case TargetMachine::CGFT_ObjectFile:
if (OS == Triple::Win32)
OutputFilename += ".obj";
else
OutputFilename += ".o";
break;
case TargetMachine::CGFT_Null:
OutputFilename += ".null";
break;
}
}
}
// Decide if we need "binary" output.
bool Binary = false;
switch (FileType) {
case TargetMachine::CGFT_AssemblyFile:
break;
case TargetMachine::CGFT_ObjectFile:
case TargetMachine::CGFT_Null:
Binary = true;
break;
}
// Open the file.
std::string error;
unsigned OpenFlags = 0;
if (Binary) OpenFlags |= raw_fd_ostream::F_Binary;
tool_output_file *FDOut = new tool_output_file(OutputFilename.c_str(), error,
OpenFlags);
if (!error.empty()) {
errs() << error << '\n';
delete FDOut;
return 0;
}
return FDOut;
}
// main - Entry point for the llc compiler.
//
int main(int argc, char **argv) {
sys::PrintStackTraceOnErrorSignal();
PrettyStackTraceProgram X(argc, argv);
// Enable debug stream buffering.
EnableDebugBuffering = true;
LLVMContext &Context = getGlobalContext();
llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
// Initialize targets first, so that --version shows registered targets.
InitializeAllTargets();
InitializeAllTargetMCs();
InitializeAllAsmPrinters();
InitializeAllAsmParsers();
// Register the target printer for --version.
cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
// Load the module to be compiled...
SMDiagnostic Err;
std::auto_ptr<Module> M;
M.reset(ParseIRFile(InputFilename, Err, Context));
if (M.get() == 0) {
Err.print(argv[0], errs());
return 1;
}
Module &mod = *M.get();
// If we are supposed to override the target triple, do so now.
if (!TargetTriple.empty())
mod.setTargetTriple(Triple::normalize(TargetTriple));
Triple TheTriple(mod.getTargetTriple());
if (TheTriple.getTriple().empty())
TheTriple.setTriple(sys::getDefaultTargetTriple());
// Allocate target machine. First, check whether the user has explicitly
// specified an architecture to compile for. If so we have to look it up by
// name, because it might be a backend that has no mapping to a target triple.
const Target *TheTarget = 0;
if (!MArch.empty()) {
for (TargetRegistry::iterator it = TargetRegistry::begin(),
ie = TargetRegistry::end(); it != ie; ++it) {
if (MArch == it->getName()) {
TheTarget = &*it;
break;
}
}
if (!TheTarget) {
errs() << argv[0] << ": error: invalid target '" << MArch << "'.\n";
return 1;
}
// Adjust the triple to match (if known), otherwise stick with the
// module/host triple.
Triple::ArchType Type = Triple::getArchTypeForLLVMName(MArch);
if (Type != Triple::UnknownArch)
TheTriple.setArch(Type);
} else {
std::string Err;
TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), Err);
if (TheTarget == 0) {
errs() << argv[0] << ": error auto-selecting target for module '"
<< Err << "'. Please use the -march option to explicitly "
<< "pick a target.\n";
return 1;
}
}
// 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();
}
CodeGenOpt::Level OLvl = CodeGenOpt::Default;
switch (OptLevel) {
default:
errs() << argv[0] << ": invalid optimization level.\n";
return 1;
case ' ': break;
case '0': OLvl = CodeGenOpt::None; break;
case '1': OLvl = CodeGenOpt::Less; break;
case '2': OLvl = CodeGenOpt::Default; break;
case '3': OLvl = CodeGenOpt::Aggressive; break;
}
TargetOptions Options;
Options.LessPreciseFPMADOption = EnableFPMAD;
Options.PrintMachineCode = PrintCode;
Options.NoFramePointerElim = DisableFPElim;
Options.NoFramePointerElimNonLeaf = DisableFPElimNonLeaf;
Options.NoExcessFPPrecision = DisableExcessPrecision;
Options.UnsafeFPMath = EnableUnsafeFPMath;
Options.NoInfsFPMath = EnableNoInfsFPMath;
Options.NoNaNsFPMath = EnableNoNaNsFPMath;
Options.HonorSignDependentRoundingFPMathOption =
EnableHonorSignDependentRoundingFPMath;
Options.UseSoftFloat = GenerateSoftFloatCalls;
if (FloatABIForCalls != FloatABI::Default)
Options.FloatABIType = FloatABIForCalls;
Options.NoZerosInBSS = DontPlaceZerosInBSS;
Options.GuaranteedTailCallOpt = EnableGuaranteedTailCallOpt;
Options.DisableTailCalls = DisableTailCalls;
Options.StackAlignmentOverride = OverrideStackAlignment;
Options.RealignStack = EnableRealignStack;
Options.DisableJumpTables = DisableSwitchTables;
Options.TrapFuncName = TrapFuncName;
Options.PositionIndependentExecutable = EnablePIE;
Options.EnableSegmentedStacks = SegmentedStacks;
std::auto_ptr<TargetMachine>
target(TheTarget->createTargetMachine(TheTriple.getTriple(),
MCPU, FeaturesStr, Options,
RelocModel, CMModel, OLvl));
assert(target.get() && "Could not allocate target machine!");
TargetMachine &Target = *target.get();
if (DisableDotLoc)
Target.setMCUseLoc(false);
if (DisableCFI)
Target.setMCUseCFI(false);
if (EnableDwarfDirectory)
Target.setMCUseDwarfDirectory(true);
if (GenerateSoftFloatCalls)
FloatABIForCalls = FloatABI::Soft;
// Disable .loc support for older OS X versions.
if (TheTriple.isMacOSX() &&
TheTriple.isMacOSXVersionLT(10, 6))
Target.setMCUseLoc(false);
// Figure out where we are going to send the output...
OwningPtr<tool_output_file> Out
(GetOutputStream(TheTarget->getName(), TheTriple.getOS(), argv[0]));
if (!Out) return 1;
// Build up all of the passes that we want to do to the module.
PassManager PM;
// Add the target data from the target machine, if it exists, or the module.
if (const TargetData *TD = Target.getTargetData())
PM.add(new TargetData(*TD));
else
PM.add(new TargetData(&mod));
// Override default to generate verbose assembly.
Target.setAsmVerbosityDefault(true);
if (RelaxAll) {
if (FileType != TargetMachine::CGFT_ObjectFile)
errs() << argv[0]
<< ": warning: ignoring -mc-relax-all because filetype != obj";
else
Target.setMCRelaxAll(true);
}
{
formatted_raw_ostream FOS(Out->os());
// Ask the target to add backend passes as necessary.
if (Target.addPassesToEmitFile(PM, FOS, FileType, NoVerify)) {
errs() << argv[0] << ": target does not support generation of this"
<< " file type!\n";
return 1;
}
// Before executing passes, print the final values of the LLVM options.
cl::PrintOptionValues();
PM.run(mod);
}
// Declare success.
Out->keep();
return 0;
}
