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      1 //===- llvm-mcld.cpp ------------------------------------------------------===//
      2 //
      3 //                     The MCLinker Project
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 #include <mcld/Module.h>
     10 #include <mcld/LinkerConfig.h>
     11 #include <mcld/Target/TargetMachine.h>
     12 #include <mcld/Support/TargetSelect.h>
     13 #include <mcld/Support/TargetRegistry.h>
     14 #include <mcld/Support/CommandLine.h>
     15 #include <mcld/Support/Path.h>
     16 #include <mcld/Support/RealPath.h>
     17 #include <mcld/Support/MsgHandling.h>
     18 #include <mcld/Support/FileHandle.h>
     19 #include <mcld/Support/FileSystem.h>
     20 #include <mcld/Support/raw_ostream.h>
     21 #include <mcld/Support/ToolOutputFile.h>
     22 #include <mcld/LD/DiagnosticLineInfo.h>
     23 #include <mcld/LD/TextDiagnosticPrinter.h>
     24 
     25 #include <llvm/PassManager.h>
     26 #include <llvm/Pass.h>
     27 #include <llvm/IR/Module.h>
     28 #include <llvm/IR/DataLayout.h>
     29 #include <llvm/IR/LLVMContext.h>
     30 #include <llvm/ADT/Triple.h>
     31 #include <llvm/MC/SubtargetFeature.h>
     32 #include <llvm/Support/CommandLine.h>
     33 #include <llvm/Support/Debug.h>
     34 #include <llvm/Support/FormattedStream.h>
     35 #include <llvm/Support/Host.h>
     36 #include <llvm/Support/IRReader.h>
     37 #include <llvm/Support/ManagedStatic.h>
     38 #include <llvm/Support/Signals.h>
     39 #include <llvm/Support/TargetRegistry.h>
     40 #include <llvm/Support/TargetSelect.h>
     41 #include <llvm/Support/Process.h>
     42 #include <llvm/Target/TargetMachine.h>
     43 
     44 #if defined(HAVE_UNISTD_H)
     45 # include <unistd.h>
     46 #endif
     47 
     48 #if defined(_MSC_VER)
     49 #include <io.h>
     50 #ifndef STDIN_FILENO
     51 # define STDIN_FILENO 0
     52 #endif
     53 #ifndef STDOUT_FILENO
     54 # define STDOUT_FILENO 1
     55 #endif
     56 #ifndef STDERR_FILENO
     57 # define STDERR_FILENO 2
     58 #endif
     59 #endif
     60 
     61 
     62 using namespace llvm;
     63 
     64 #ifdef ENABLE_UNITTEST
     65 #include <gtest.h>
     66 
     67 static cl::opt<bool>
     68 UnitTest("unittest",  cl::desc("do unit test") );
     69 
     70 int unit_test( int argc, char* argv[] )
     71 {
     72   testing::InitGoogleTest( &argc, argv );
     73   return RUN_ALL_TESTS();
     74 }
     75 
     76 #endif
     77 
     78 // General options for llc.  Other pass-specific options are specified
     79 // within the corresponding llc passes, and target-specific options
     80 // and back-end code generation options are specified with the target machine.
     81 //
     82 // Determine optimization level.
     83 static cl::opt<char>
     84 OptLevel("O",
     85          cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
     86                   "(default = '-O2')"),
     87          cl::Prefix,
     88          cl::ZeroOrMore,
     89          cl::init(' '));
     90 
     91 static cl::opt<std::string>
     92 TargetTriple("mtriple", cl::desc("Override target triple for module"));
     93 
     94 static cl::opt<std::string>
     95 MArch("march", cl::desc("Architecture to generate code for (see --version)"));
     96 
     97 static cl::opt<std::string>
     98 MCPU("mcpu",
     99   cl::desc("Target a specific cpu type (-mcpu=help for details)"),
    100   cl::value_desc("cpu-name"),
    101   cl::init(""));
    102 
    103 static cl::list<std::string>
    104 MAttrs("mattr",
    105   cl::CommaSeparated,
    106   cl::desc("Target specific attributes (-mattr=help for details)"),
    107   cl::value_desc("a1,+a2,-a3,..."));
    108 
    109 static cl::opt<llvm::CodeModel::Model>
    110 CMModel("code-model",
    111         cl::desc("Choose code model"),
    112         cl::init(CodeModel::Default),
    113         cl::values(clEnumValN(CodeModel::Default, "default",
    114                               "Target default code model"),
    115                    clEnumValN(CodeModel::Small, "small",
    116                               "Small code model"),
    117                    clEnumValN(CodeModel::Kernel, "kernel",
    118                               "Kernel code model"),
    119                    clEnumValN(CodeModel::Medium, "medium",
    120                               "Medium code model"),
    121                    clEnumValN(CodeModel::Large, "large",
    122                               "Large code model"),
    123                    clEnumValEnd));
    124 
    125 cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
    126                        cl::desc("Do not verify input module"));
    127 
    128 static cl::opt<bool>
    129 EnableFPMAD("enable-fp-mad",
    130   cl::desc("Enable less precise MAD instructions to be generated"),
    131   cl::init(false));
    132 
    133 static cl::opt<bool>
    134 DisableFPElim("disable-fp-elim",
    135   cl::desc("Disable frame pointer elimination optimization"),
    136   cl::init(false));
    137 
    138 static cl::opt<bool>
    139 DisableFPElimNonLeaf("disable-non-leaf-fp-elim",
    140   cl::desc("Disable frame pointer elimination optimization for non-leaf funcs"),
    141   cl::init(false));
    142 
    143 static cl::opt<llvm::FPOpFusion::FPOpFusionMode>
    144 FuseFPOps("fuse-fp-ops",
    145   cl::desc("Enable aggresive formation of fused FP ops"),
    146   cl::init(FPOpFusion::Standard),
    147   cl::values(
    148     clEnumValN(FPOpFusion::Fast, "fast",
    149                "Fuse FP ops whenever profitable"),
    150     clEnumValN(FPOpFusion::Standard, "standard",
    151                "Only fuse 'blessed' FP ops."),
    152     clEnumValN(FPOpFusion::Strict, "strict",
    153                "Only fuse FP ops when the result won't be effected."),
    154     clEnumValEnd));
    155 
    156 static cl::opt<bool>
    157 EnableUnsafeFPMath("enable-unsafe-fp-math",
    158   cl::desc("Enable optimizations that may decrease FP precision"),
    159   cl::init(false));
    160 
    161 static cl::opt<bool>
    162 EnableNoInfsFPMath("enable-no-infs-fp-math",
    163   cl::desc("Enable FP math optimizations that assume no +-Infs"),
    164   cl::init(false));
    165 
    166 static cl::opt<bool>
    167 EnableNoNaNsFPMath("enable-no-nans-fp-math",
    168   cl::desc("Enable FP math optimizations that assume no NaNs"),
    169   cl::init(false));
    170 
    171 static cl::opt<bool>
    172 EnableHonorSignDependentRoundingFPMath("enable-sign-dependent-rounding-fp-math",
    173   cl::Hidden,
    174   cl::desc("Force codegen to assume rounding mode can change dynamically"),
    175   cl::init(false));
    176 
    177 static cl::opt<bool>
    178 GenerateSoftFloatCalls("soft-float",
    179   cl::desc("Generate software floating point library calls"),
    180   cl::init(false));
    181 
    182 static cl::opt<llvm::FloatABI::ABIType>
    183 FloatABIForCalls("float-abi",
    184   cl::desc("Choose float ABI type"),
    185   cl::init(FloatABI::Default),
    186   cl::values(
    187     clEnumValN(FloatABI::Default, "default",
    188                "Target default float ABI type"),
    189     clEnumValN(FloatABI::Soft, "soft",
    190                "Soft float ABI (implied by -soft-float)"),
    191     clEnumValN(FloatABI::Hard, "hard",
    192                "Hard float ABI (uses FP registers)"),
    193     clEnumValEnd));
    194 
    195 static cl::opt<bool>
    196 DontPlaceZerosInBSS("nozero-initialized-in-bss",
    197   cl::desc("Don't place zero-initialized symbols into bss section"),
    198   cl::init(false));
    199 
    200 static cl::opt<bool>
    201 EnableJITExceptionHandling("jit-enable-eh",
    202   cl::desc("Emit exception handling information"),
    203   cl::init(false));
    204 
    205 // In debug builds, make this default to true.
    206 #ifdef NDEBUG
    207 #define EMIT_DEBUG false
    208 #else
    209 #define EMIT_DEBUG true
    210 #endif
    211 static cl::opt<bool>
    212 EmitJitDebugInfo("jit-emit-debug",
    213   cl::desc("Emit debug information to debugger"),
    214   cl::init(EMIT_DEBUG));
    215 #undef EMIT_DEBUG
    216 
    217 static cl::opt<bool>
    218 EmitJitDebugInfoToDisk("jit-emit-debug-to-disk",
    219   cl::Hidden,
    220   cl::desc("Emit debug info objfiles to disk"),
    221   cl::init(false));
    222 
    223 static cl::opt<bool>
    224 EnableGuaranteedTailCallOpt("tailcallopt",
    225   cl::desc("Turn fastcc calls into tail calls by (potentially) changing ABI."),
    226   cl::init(false));
    227 
    228 static cl::opt<unsigned>
    229 OverrideStackAlignment("stack-alignment",
    230   cl::desc("Override default stack alignment"),
    231   cl::init(0));
    232 
    233 static cl::opt<bool>
    234 EnableRealignStack("realign-stack",
    235   cl::desc("Realign stack if needed"),
    236   cl::init(true));
    237 
    238 static cl::opt<std::string>
    239 TrapFuncName("trap-func", cl::Hidden,
    240   cl::desc("Emit a call to trap function rather than a trap instruction"),
    241   cl::init(""));
    242 
    243 static cl::opt<bool>
    244 SegmentedStacks("segmented-stacks",
    245   cl::desc("Use segmented stacks if possible."),
    246   cl::init(false));
    247 
    248 //===----------------------------------------------------------------------===//
    249 // Command Line Options
    250 // There are four kinds of command line options:
    251 //   1. Bitcode option. Used to represent a bitcode.
    252 //   2. Attribute options. Attributes describes the input file after them. For
    253 //      example, --as-needed affects the input file after this option. Attribute
    254 //      options are not attributes. Attribute options are the options that is
    255 //      used to define a legal attribute.
    256 //   3. Scripting options, Used to represent a subset of link scripting
    257 //      language, such as --defsym.
    258 //   4. General options. (the rest of options)
    259 //===----------------------------------------------------------------------===//
    260 // Bitcode Options
    261 //===----------------------------------------------------------------------===//
    262 static cl::opt<mcld::sys::fs::Path, false, llvm::cl::parser<mcld::sys::fs::Path> >
    263 ArgBitcodeFilename("dB",
    264               cl::desc("set default bitcode"),
    265               cl::value_desc("bitcode"));
    266 
    267 //===----------------------------------------------------------------------===//
    268 // General Options
    269 //===----------------------------------------------------------------------===//
    270 static cl::opt<mcld::sys::fs::Path, false, llvm::cl::parser<mcld::sys::fs::Path> >
    271 ArgOutputFilename("o",
    272                cl::desc("Output filename"),
    273                cl::value_desc("filename"));
    274 
    275 static cl::alias
    276 AliasOutputFilename("output",
    277                     cl::desc("alias for -o"),
    278                     cl::aliasopt(ArgOutputFilename));
    279 
    280 static cl::opt<mcld::sys::fs::Path, false, llvm::cl::parser<mcld::sys::fs::Path> >
    281 ArgSysRoot("sysroot",
    282            cl::desc("Use directory as the location of the sysroot, overriding the configure-time default."),
    283            cl::value_desc("directory"),
    284            cl::ValueRequired);
    285 
    286 static cl::list<std::string, bool, llvm::cl::SearchDirParser>
    287 ArgSearchDirList("L",
    288                  cl::ZeroOrMore,
    289                  cl::desc("Add path searchdir to the list of paths that ld will search for archive libraries and ld control scripts."),
    290                  cl::value_desc("searchdir"),
    291                  cl::Prefix);
    292 
    293 static cl::alias
    294 ArgSearchDirListAlias("library-path",
    295                       cl::desc("alias for -L"),
    296                       cl::aliasopt(ArgSearchDirList));
    297 
    298 static cl::opt<bool>
    299 ArgTrace("t",
    300          cl::desc("Print the names of the input files as ld processes them."));
    301 
    302 static cl::alias
    303 ArgTraceAlias("trace",
    304               cl::desc("alias for -t"),
    305               cl::aliasopt(ArgTrace));
    306 
    307 static cl::opt<int>
    308 ArgVerbose("verbose",
    309            cl::init(-1),
    310            cl::desc("Display the version number for ld and list the linker emulations supported."));
    311 
    312 static cl::opt<bool>
    313 ArgVersion("V",
    314            cl::init(false),
    315            cl::desc("Display the version number for MCLinker."));
    316 
    317 static cl::opt<int>
    318 ArgMaxErrorNum("error-limit",
    319                cl::init(-1),
    320                cl::desc("limits the maximum number of erros."));
    321 
    322 static cl::opt<int>
    323 ArgMaxWarnNum("warning-limit",
    324                cl::init(-1),
    325                cl::desc("limits the maximum number of warnings."));
    326 
    327 static cl::opt<std::string>
    328 ArgEntry("e",
    329          cl::desc("Use entry as the explicit symbol for beginning execution of your program."),
    330          cl::value_desc("entry"),
    331          cl::ValueRequired);
    332 
    333 static cl::alias
    334 ArgEntryAlias("entry",
    335               cl::desc("alias for -e"),
    336               cl::aliasopt(ArgEntry));
    337 
    338 static cl::opt<bool>
    339 ArgBsymbolic("Bsymbolic",
    340              cl::desc("Bind references within the shared library."),
    341              cl::init(false));
    342 
    343 static cl::opt<bool>
    344 ArgBgroup("Bgroup",
    345           cl::desc("Info the dynamic linker to perform lookups only inside the group."),
    346           cl::init(false));
    347 
    348 static cl::opt<std::string>
    349 ArgSOName("soname",
    350           cl::desc("Set internal name of shared library"),
    351           cl::value_desc("name"));
    352 
    353 static cl::opt<bool>
    354 ArgNoUndefined("no-undefined",
    355                cl::desc("Do not allow unresolved references"),
    356                cl::init(false));
    357 
    358 static cl::opt<bool>
    359 ArgAllowMulDefs("allow-multiple-definition",
    360                 cl::desc("Allow multiple definition"),
    361                 cl::init(false));
    362 
    363 static cl::opt<bool>
    364 ArgEhFrameHdr("eh-frame-hdr",
    365               cl::desc("Request creation of \".eh_frame_hdr\" section and ELF \"PT_GNU_EH_FRAME\" segment header."),
    366               cl::init(false));
    367 
    368 static cl::list<mcld::ZOption, bool, llvm::cl::parser<mcld::ZOption> >
    369 ArgZOptionList("z",
    370                cl::ZeroOrMore,
    371                cl::desc("The -z options for GNU ld compatibility."),
    372                cl::value_desc("keyword"),
    373                cl::Prefix);
    374 
    375 cl::opt<mcld::CodeGenFileType>
    376 ArgFileType("filetype", cl::init(mcld::CGFT_EXEFile),
    377   cl::desc("Choose a file type (not all types are supported by all targets):"),
    378   cl::values(
    379        clEnumValN(mcld::CGFT_ASMFile, "asm",
    380                   "Emit an assembly ('.s') file"),
    381        clEnumValN(mcld::CGFT_OBJFile, "obj",
    382                   "Emit a relocatable object ('.o') file"),
    383        clEnumValN(mcld::CGFT_DSOFile, "dso",
    384                   "Emit an dynamic shared object ('.so') file"),
    385        clEnumValN(mcld::CGFT_EXEFile, "exe",
    386                   "Emit a executable ('.exe') file"),
    387        clEnumValN(mcld::CGFT_NULLFile, "null",
    388                   "Emit nothing, for performance testing"),
    389        clEnumValEnd));
    390 
    391 static cl::opt<bool>
    392 ArgShared("shared",
    393           cl::desc("Create a shared library."),
    394           cl::init(false));
    395 
    396 static cl::alias
    397 ArgSharedAlias("Bshareable",
    398                cl::desc("alias for -shared"),
    399                cl::aliasopt(ArgShared));
    400 
    401 static cl::opt<bool>
    402 ArgPIE("pie",
    403        cl::desc("Emit a position-independent executable file"),
    404        cl::init(false));
    405 
    406 static cl::opt<bool>
    407 ArgRelocatable("relocatable",
    408                cl::desc("Generate relocatable output"),
    409                cl::init(false));
    410 
    411 static cl::alias
    412 ArgRelocatableAlias("r",
    413                     cl::desc("alias for --relocatable"),
    414                     cl::aliasopt(ArgRelocatable));
    415 
    416 static cl::opt<Reloc::Model>
    417 ArgRelocModel("relocation-model",
    418              cl::desc("Choose relocation model"),
    419              cl::init(Reloc::Default),
    420              cl::values(
    421                clEnumValN(Reloc::Default, "default",
    422                        "Target default relocation model"),
    423                clEnumValN(Reloc::Static, "static",
    424                        "Non-relocatable code"),
    425                clEnumValN(Reloc::PIC_, "pic",
    426                        "Fully relocatable, position independent code"),
    427                clEnumValN(Reloc::DynamicNoPIC, "dynamic-no-pic",
    428                        "Relocatable external references, non-relocatable code"),
    429                clEnumValEnd));
    430 
    431 static cl::opt<bool>
    432 ArgFPIC("fPIC",
    433         cl::desc("Set relocation model to pic. The same as -relocation-model=pic."),
    434         cl::init(false));
    435 
    436 static cl::opt<std::string>
    437 ArgDyld("dynamic-linker",
    438         cl::ZeroOrMore,
    439         cl::desc("Set the name of the dynamic linker."),
    440         cl::value_desc("Program"));
    441 
    442 namespace color {
    443 enum Color {
    444   Never,
    445   Always,
    446   Auto
    447 };
    448 } // namespace of color
    449 
    450 static cl::opt<color::Color>
    451 ArgColor("color",
    452   cl::value_desc("WHEN"),
    453   cl::desc("Surround the result strings with the marker"),
    454   cl::init(color::Auto),
    455   cl::values(
    456     clEnumValN(color::Never, "never",
    457       "do not surround result strings"),
    458     clEnumValN(color::Always, "always",
    459       "always surround result strings, even the output is a plain file"),
    460     clEnumValN(color::Auto, "auto",
    461       "surround result strings only if the output is a tty"),
    462     clEnumValEnd));
    463 
    464 static cl::opt<bool>
    465 ArgDiscardLocals("discard-locals",
    466                  cl::desc("Delete all temporary local symbols."),
    467                  cl::init(false));
    468 
    469 static cl::alias
    470 ArgDiscardLocalsAlias("X",
    471                       cl::desc("alias for --discard-locals"),
    472                       cl::aliasopt(ArgDiscardLocals));
    473 
    474 static cl::opt<bool>
    475 ArgDiscardAll("discard-all",
    476               cl::desc("Delete all local symbols."),
    477               cl::init(false));
    478 
    479 static cl::alias
    480 ArgDiscardAllAlias("x",
    481                    cl::desc("alias for --discard-all"),
    482                    cl::aliasopt(ArgDiscardAll));
    483 
    484 static cl::opt<bool>
    485 ArgStripDebug("strip-debug",
    486               cl::desc("Omit debugger symbol information from the output file."),
    487               cl::init(false));
    488 
    489 static cl::alias
    490 ArgStripDebugAlias("S",
    491                    cl::desc("alias for --strip-debug"),
    492                    cl::aliasopt(ArgStripDebug));
    493 
    494 static cl::opt<bool>
    495 ArgStripAll("strip-all",
    496             cl::desc("Omit all symbol information from the output file."),
    497             cl::init(false));
    498 
    499 static cl::alias
    500 ArgStripAllAlias("s",
    501                  cl::desc("alias for --strip-all"),
    502                  cl::aliasopt(ArgStripAll));
    503 
    504 static cl::opt<bool>
    505 ArgNMagic("nmagic",
    506           cl::desc("Do not page align data"),
    507           cl::init(false));
    508 
    509 static cl::alias
    510 ArgNMagicAlias("n",
    511                cl::desc("alias for --nmagic"),
    512                cl::aliasopt(ArgNMagic));
    513 
    514 static cl::opt<bool>
    515 ArgOMagic("omagic",
    516           cl::desc("Do not page align data, do not make text readonly"),
    517           cl::init(false));
    518 
    519 static cl::alias
    520 ArgOMagicAlias("N",
    521                cl::desc("alias for --omagic"),
    522                cl::aliasopt(ArgOMagic));
    523 
    524 /// @{
    525 /// @name FIXME: begin of unsupported options
    526 /// @}
    527 static cl::opt<bool>
    528 ArgGCSections("gc-sections",
    529               cl::desc("Enable garbage collection of unused input sections."),
    530               cl::init(false));
    531 
    532 static cl::opt<bool>
    533 ArgNoGCSections("no-gc-sections",
    534               cl::desc("disable garbage collection of unused input sections."),
    535               cl::init(false));
    536 
    537 namespace icf {
    538 enum Mode {
    539   None,
    540   All,
    541   Safe
    542 };
    543 } // namespace of icf
    544 
    545 static cl::opt<icf::Mode>
    546 ArgICF("icf",
    547        cl::ZeroOrMore,
    548        cl::desc("Identical Code Folding"),
    549        cl::init(icf::None),
    550        cl::values(
    551          clEnumValN(icf::None, "none",
    552            "do not perform cold folding"),
    553          clEnumValN(icf::All, "all",
    554            "always preform cold folding"),
    555          clEnumValN(icf::Safe, "safe",
    556            "Folds ctors, dtors and functions whose pointers are definitely not taken."),
    557          clEnumValEnd));
    558 
    559 // FIXME: add this to target options?
    560 static cl::opt<bool>
    561 ArgFIXCA8("fix-cortex-a8",
    562           cl::desc("Enable Cortex-A8 Thumb-2 branch erratum fix"),
    563           cl::init(false));
    564 
    565 static cl::opt<bool>
    566 ArgExportDynamic("export-dynamic",
    567                  cl::desc("Export all dynamic symbols"),
    568                  cl::init(false));
    569 
    570 static cl::alias
    571 ArgExportDynamicAlias("E",
    572                       cl::desc("alias for --export-dynamic"),
    573                       cl::aliasopt(ArgExportDynamic));
    574 
    575 static cl::opt<std::string>
    576 ArgEmulation("m",
    577              cl::desc("Set GNU linker emulation"),
    578              cl::value_desc("emulation"));
    579 
    580 static cl::list<std::string, bool, llvm::cl::SearchDirParser>
    581 ArgRuntimePathLink("rpath-link",
    582                    cl::ZeroOrMore,
    583                    cl::desc("Add a directory to the link time library search path"),
    584                    cl::value_desc("dir"));
    585 
    586 static cl::list<std::string>
    587 ArgExcludeLIBS("exclude-libs",
    588                cl::CommaSeparated,
    589                cl::desc("Exclude libraries from automatic export"),
    590                cl::value_desc("lib1,lib2,..."));
    591 
    592 static cl::opt<std::string>
    593 ArgBuildID("build-id",
    594            cl::desc("Request creation of \".note.gnu.build-id\" ELF note section."),
    595            cl::value_desc("style"));
    596 
    597 static cl::opt<std::string>
    598 ArgForceUndefined("u",
    599                   cl::desc("Force symbol to be undefined in the output file"),
    600                   cl::value_desc("symbol"));
    601 
    602 static cl::alias
    603 ArgForceUndefinedAlias("undefined",
    604                        cl::desc("alias for -u"),
    605                        cl::aliasopt(ArgForceUndefined));
    606 
    607 static cl::opt<std::string>
    608 ArgVersionScript("version-script",
    609                  cl::desc("Version script."),
    610                  cl::value_desc("Version script"));
    611 
    612 static cl::opt<bool>
    613 ArgWarnCommon("warn-common",
    614               cl::desc("warn common symbol"),
    615               cl::init(false));
    616 
    617 static cl::opt<mcld::GeneralOptions::HashStyle>
    618 ArgHashStyle("hash-style", cl::init(mcld::GeneralOptions::SystemV),
    619   cl::desc("Set the type of linker's hash table(s)."),
    620   cl::values(
    621        clEnumValN(mcld::GeneralOptions::SystemV, "sysv",
    622                  "classic ELF .hash section"),
    623        clEnumValN(mcld::GeneralOptions::GNU, "gnu",
    624                  "new style GNU .gnu.hash section"),
    625        clEnumValN(mcld::GeneralOptions::Both, "both",
    626                  "both the classic ELF and new style GNU hash tables"),
    627        clEnumValEnd));
    628 
    629 static cl::opt<std::string>
    630 ArgFilter("F",
    631           cl::desc("Filter for shared object symbol table"),
    632           cl::value_desc("name"));
    633 
    634 static cl::alias
    635 ArgFilterAlias("filter",
    636                cl::desc("alias for -F"),
    637                cl::aliasopt(ArgFilterAlias));
    638 
    639 static cl::list<std::string>
    640 ArgAuxiliary("f",
    641              cl::ZeroOrMore,
    642              cl::desc("Auxiliary filter for shared object symbol table"),
    643              cl::value_desc("name"));
    644 
    645 static cl::alias
    646 ArgAuxiliaryAlias("auxiliary",
    647                   cl::desc("alias for -f"),
    648                   cl::aliasopt(ArgAuxiliary));
    649 
    650 static cl::opt<bool>
    651 ArgEB("EB",
    652       cl::desc("Link big-endian objects. This affects the default output format."),
    653       cl::init(false));
    654 
    655 static cl::opt<bool>
    656 ArgEL("EL",
    657       cl::desc("Link little-endian objects. This affects the default output format."),
    658       cl::init(false));
    659 
    660 /// @{
    661 /// @name FIXME: end of unsupported options
    662 /// @}
    663 
    664 static cl::opt<bool>
    665 ArgNoStdlib("nostdlib",
    666             cl::desc("Only search lib dirs explicitly specified on cmdline"),
    667             cl::init(false));
    668 
    669 static cl::list<std::string, bool, llvm::cl::SearchDirParser>
    670 ArgRuntimePath("rpath",
    671                cl::ZeroOrMore,
    672                cl::desc("Add a directory to the runtime library search path"),
    673                cl::value_desc("dir"));
    674 
    675 static cl::alias
    676 ArgRuntimePathAlias("R",
    677                     cl::desc("alias for --rpath"),
    678                     cl::aliasopt(ArgRuntimePath), cl::Prefix);
    679 
    680 static cl::opt<bool>
    681 ArgEnableNewDTags("enable-new-dtags",
    682                   cl::desc("Enable use of DT_RUNPATH and DT_FLAGS"),
    683                   cl::init(false));
    684 
    685 class FalseParser : public cl::parser<bool> {
    686   const char *ArgStr;
    687 public:
    688 
    689   // parse - Return true on error.
    690   bool parse(cl::Option &O, StringRef ArgName, StringRef Arg, bool &Val) {
    691     if (cl::parser<bool>::parse(O, ArgName, Arg, Val))
    692       return false;
    693     Val = false;
    694     return false;
    695   }
    696 };
    697 
    698 static bool ArgFatalWarnings;
    699 
    700 static cl::opt<bool, true, FalseParser>
    701 ArgNoFatalWarnings("no-fatal-warnings",
    702               cl::location(ArgFatalWarnings),
    703               cl::desc("do not turn warnings into errors"),
    704               cl::init(false),
    705               cl::ValueDisallowed);
    706 
    707 static cl::opt<bool, true>
    708 ArgFatalWarnings_("fatal-warnings",
    709               cl::location(ArgFatalWarnings),
    710               cl::desc("turn all warnings into errors"),
    711               cl::init(false),
    712               cl::ValueDisallowed);
    713 
    714 static cl::opt<bool>
    715 ArgWarnSharedTextrel("warn-shared-textrel",
    716                      cl::desc("Warn if adding DT_TEXTREL in a shared object."),
    717                      cl::init(false));
    718 
    719 namespace format {
    720 enum Format {
    721   Binary,
    722   Unknown // decided by triple
    723 };
    724 } // namespace of format
    725 
    726 static cl::opt<format::Format>
    727 ArgFormat("b",
    728   cl::value_desc("Format"),
    729   cl::desc("set input format"),
    730   cl::init(format::Unknown),
    731   cl::values(
    732     clEnumValN(format::Binary, "binary",
    733       "read in binary machine code."),
    734     clEnumValEnd));
    735 
    736 static cl::alias
    737 ArgFormatAlias("format",
    738                cl::desc("alias for -b"),
    739                cl::aliasopt(ArgFormat));
    740 
    741 static cl::opt<format::Format>
    742 ArgOFormat("oformat",
    743   cl::value_desc("Format"),
    744   cl::desc("set output format"),
    745   cl::init(format::Unknown),
    746   cl::values(
    747     clEnumValN(format::Binary, "binary",
    748       "generate binary machine code."),
    749     clEnumValEnd));
    750 
    751 static cl::opt<bool>
    752 ArgDefineCommon("d",
    753                 cl::ZeroOrMore,
    754                 cl::desc("Define common symbol"),
    755                 cl::init(false));
    756 
    757 static cl::alias
    758 ArgDefineCommonAlias1("dc",
    759                       cl::desc("alias for -d"),
    760                       cl::aliasopt(ArgDefineCommon));
    761 
    762 static cl::alias
    763 ArgDefineCommonAlias2("dp",
    764                       cl::desc("alias for -d"),
    765                       cl::aliasopt(ArgDefineCommon));
    766 
    767 //===----------------------------------------------------------------------===//
    768 // Scripting Options
    769 //===----------------------------------------------------------------------===//
    770 static cl::list<std::string>
    771 ArgWrapList("wrap",
    772             cl::ZeroOrMore,
    773             cl::desc("Use a wrap function fo symbol."),
    774             cl::value_desc("symbol"));
    775 
    776 static cl::list<std::string>
    777 ArgPortList("portable",
    778             cl::ZeroOrMore,
    779             cl::desc("Use a portable function fo symbol."),
    780             cl::value_desc("symbol"));
    781 
    782 static cl::list<std::string>
    783 ArgAddressMapList("section-start",
    784                   cl::ZeroOrMore,
    785                   cl::desc("Locate a output section at the given absolute address"),
    786                   cl::value_desc("Set address of section"),
    787                   cl::Prefix);
    788 
    789 static cl::opt<unsigned long long>
    790 ArgBssSegAddr("Tbss",
    791               cl::desc("Set the address of the bss segment"),
    792               cl::init(-1U));
    793 
    794 static cl::opt<unsigned long long>
    795 ArgDataSegAddr("Tdata",
    796                cl::desc("Set the address of the data segment"),
    797                cl::init(-1U));
    798 
    799 static cl::opt<unsigned long long>
    800 ArgTextSegAddr("Ttext",
    801                cl::desc("Set the address of the text segment"),
    802                cl::init(-1U));
    803 
    804 //===----------------------------------------------------------------------===//
    805 // non-member functions
    806 //===----------------------------------------------------------------------===//
    807 /// GetOutputStream - get the output stream.
    808 static mcld::ToolOutputFile *GetOutputStream(const char* pTargetName,
    809                                              Triple::OSType pOSType,
    810                                              mcld::CodeGenFileType pFileType,
    811                                              const mcld::sys::fs::Path& pInputFilename,
    812                                              mcld::sys::fs::Path& pOutputFilename)
    813 {
    814   if (pOutputFilename.empty()) {
    815     if (0 == pInputFilename.native().compare("-"))
    816       pOutputFilename.assign("-");
    817     else {
    818       switch(pFileType) {
    819       case mcld::CGFT_ASMFile: {
    820         if (0 == pInputFilename.native().compare("-"))
    821           pOutputFilename.assign("_out");
    822         else
    823           pOutputFilename.assign(pInputFilename.stem().native());
    824 
    825         if (0 == strcmp(pTargetName, "c"))
    826           pOutputFilename.native() += ".cbe.c";
    827         else if (0 == strcmp(pTargetName, "cpp"))
    828           pOutputFilename.native() += ".cpp";
    829         else
    830           pOutputFilename.native() += ".s";
    831       }
    832       break;
    833 
    834       case mcld::CGFT_OBJFile: {
    835         if (0 == pInputFilename.native().compare("-"))
    836           pOutputFilename.assign("_out");
    837         else
    838           pOutputFilename.assign(pInputFilename.stem().native());
    839 
    840         if (pOSType == Triple::Win32)
    841           pOutputFilename.native() += ".obj";
    842         else
    843           pOutputFilename.native() += ".o";
    844       }
    845       break;
    846 
    847       case mcld::CGFT_PARTIAL: {
    848         if (Triple::Win32 == pOSType) {
    849           if (0 == pInputFilename.native().compare("-"))
    850             pOutputFilename.assign("_out");
    851           else
    852             pOutputFilename.assign(pInputFilename.stem().native());
    853           pOutputFilename.native() += ".obj";
    854         }
    855         else
    856           pOutputFilename.assign("a.out");
    857       }
    858       break;
    859 
    860       case mcld::CGFT_DSOFile: {
    861         if (Triple::Win32 == pOSType) {
    862           if (0 == pInputFilename.native().compare("-"))
    863             pOutputFilename.assign("_out");
    864           else
    865             pOutputFilename.assign(pInputFilename.stem().native());
    866           pOutputFilename.native() += ".dll";
    867         }
    868         else
    869           pOutputFilename.assign("a.out");
    870       }
    871       break;
    872 
    873       case mcld::CGFT_EXEFile: {
    874         if (Triple::Win32 == pOSType) {
    875           if (0 == pInputFilename.native().compare("-"))
    876             pOutputFilename.assign("_out");
    877           else
    878             pOutputFilename.assign(pInputFilename.stem().native());
    879           pOutputFilename.native() += ".exe";
    880         }
    881         else
    882           pOutputFilename.assign("a.out");
    883       }
    884       break;
    885 
    886       case mcld::CGFT_NULLFile:
    887         break;
    888       default:
    889         llvm::report_fatal_error("Unknown output file type.\n");
    890       } // end of switch
    891     } // end of ! pInputFilename == "-"
    892   } // end of if empty pOutputFilename
    893 
    894   mcld::FileHandle::Permission permission;
    895   switch (pFileType) {
    896   default: assert(0 && "Unknown file type");
    897   case mcld::CGFT_ASMFile:
    898   case mcld::CGFT_OBJFile:
    899   case mcld::CGFT_PARTIAL:
    900     permission = 0644;
    901     break;
    902   case mcld::CGFT_DSOFile:
    903   case mcld::CGFT_EXEFile:
    904   case mcld::CGFT_BINARY:
    905   case mcld::CGFT_NULLFile:
    906     permission = 0755;
    907     break;
    908   }
    909 
    910   // Open the file.
    911   mcld::ToolOutputFile* result_output =
    912                       new mcld::ToolOutputFile(pOutputFilename,
    913                                                  mcld::FileHandle::ReadWrite |
    914                                                  mcld::FileHandle::Create |
    915                                                  mcld::FileHandle::Truncate,
    916                                                permission);
    917 
    918   return result_output;
    919 }
    920 
    921 /// ParseProgName - Parse program name
    922 /// This function simplifies cross-compiling by reading triple from the program
    923 /// name. For example, if the program name is `arm-linux-eabi-ld.mcld', we can
    924 /// get the triple is arm-linux-eabi by the program name.
    925 static void ParseProgName(const char *progname)
    926 {
    927   static const char *suffixes[] = {
    928     "ld",
    929     "ld.mcld",
    930   };
    931 
    932   std::string ProgName(mcld::sys::fs::Path(progname).stem().native());
    933 
    934   for (size_t i = 0; i < sizeof(suffixes) / sizeof(suffixes[0]); ++i) {
    935     if (ProgName == suffixes[i])
    936       return;
    937   }
    938 
    939   StringRef ProgNameRef(ProgName);
    940   StringRef Prefix;
    941 
    942   for (size_t i = 0; i < sizeof(suffixes) / sizeof(suffixes[0]); ++i) {
    943     if (!ProgNameRef.endswith(suffixes[i]))
    944       continue;
    945 
    946     StringRef::size_type LastComponent = ProgNameRef.rfind('-',
    947       ProgNameRef.size() - strlen(suffixes[i]));
    948     if (LastComponent == StringRef::npos)
    949       continue;
    950     StringRef Prefix = ProgNameRef.slice(0, LastComponent);
    951     std::string IgnoredError;
    952     if (!llvm::TargetRegistry::lookupTarget(Prefix, IgnoredError))
    953       continue;
    954     TargetTriple = Prefix.str();
    955     return;
    956   }
    957 }
    958 
    959 static bool ShouldColorize()
    960 {
    961    const char* term = getenv("TERM");
    962    return term && (0 != strcmp(term, "dumb"));
    963 }
    964 
    965 static bool ProcessLinkerOptionsFromCommand(mcld::LinkerConfig& pConfig) {
    966   // -----  Set up General Options  ----- //
    967   // set up colorize
    968   switch (ArgColor) {
    969     case color::Never:
    970       pConfig.options().setColor(false);
    971     break;
    972     case color::Always:
    973       pConfig.options().setColor(true);
    974     break;
    975     case color::Auto:
    976       bool color_option = ShouldColorize() &&
    977                  llvm::sys::Process::FileDescriptorIsDisplayed(STDOUT_FILENO);
    978       pConfig.options().setColor(color_option);
    979     break;
    980   }
    981 
    982   mcld::outs().setColor(pConfig.options().color());
    983   mcld::errs().setColor(pConfig.options().color());
    984 
    985   // set up soname
    986   pConfig.options().setSOName(ArgSOName);
    987 
    988   // add all rpath entries
    989   cl::list<std::string>::iterator rp;
    990   cl::list<std::string>::iterator rpEnd = ArgRuntimePath.end();
    991   for (rp = ArgRuntimePath.begin(); rp != rpEnd; ++rp) {
    992     pConfig.options().getRpathList().push_back(*rp);
    993   }
    994 
    995   // --fatal-warnings
    996   // pConfig.options().setFatalWarnings(ArgFatalWarnings);
    997 
    998   // -shared or -pie
    999   if (true == ArgShared || true == ArgPIE) {
   1000     ArgFileType = mcld::CGFT_DSOFile;
   1001   }
   1002   else if (true == ArgRelocatable) {
   1003     ArgFileType = mcld::CGFT_PARTIAL;
   1004   }
   1005   else if (format::Binary == ArgOFormat) {
   1006     ArgFileType = mcld::CGFT_BINARY;
   1007   }
   1008 
   1009   // -b [input-format], --format=[input-format]
   1010   if (format::Binary == ArgFormat)
   1011     pConfig.options().setBinaryInput();
   1012 
   1013   // -V
   1014   if (ArgVersion) {
   1015     mcld::outs() << "MCLinker - "
   1016                  << mcld::LinkerConfig::version()
   1017                  << "\n";
   1018   }
   1019 
   1020   // set up sysroot
   1021   if (!ArgSysRoot.empty()) {
   1022     if (exists(ArgSysRoot) && is_directory(ArgSysRoot))
   1023       pConfig.options().setSysroot(ArgSysRoot);
   1024   }
   1025 
   1026   // add all search directories
   1027   cl::list<std::string>::iterator sd;
   1028   cl::list<std::string>::iterator sdEnd = ArgSearchDirList.end();
   1029   for (sd=ArgSearchDirList.begin(); sd!=sdEnd; ++sd) {
   1030     if (!pConfig.options().directories().insert(*sd)) {
   1031       // FIXME: need a warning function
   1032       errs() << "WARNING: can not open search directory `-L"
   1033              << *sd
   1034              << "'.\n";
   1035     }
   1036   }
   1037 
   1038   pConfig.options().setPIE(ArgPIE);
   1039   pConfig.options().setTrace(ArgTrace);
   1040   pConfig.options().setVerbose(ArgVerbose);
   1041   pConfig.options().setMaxErrorNum(ArgMaxErrorNum);
   1042   pConfig.options().setMaxWarnNum(ArgMaxWarnNum);
   1043   pConfig.options().setEntry(ArgEntry);
   1044   pConfig.options().setBsymbolic(ArgBsymbolic);
   1045   pConfig.options().setBgroup(ArgBgroup);
   1046   pConfig.options().setDyld(ArgDyld);
   1047   pConfig.options().setNoUndefined(ArgNoUndefined);
   1048   pConfig.options().setMulDefs(ArgAllowMulDefs);
   1049   pConfig.options().setEhFrameHdr(ArgEhFrameHdr);
   1050   pConfig.options().setNMagic(ArgNMagic);
   1051   pConfig.options().setOMagic(ArgOMagic);
   1052   pConfig.options().setStripDebug(ArgStripDebug || ArgStripAll);
   1053   pConfig.options().setExportDynamic(ArgExportDynamic);
   1054   pConfig.options().setWarnSharedTextrel(ArgWarnSharedTextrel);
   1055   pConfig.options().setDefineCommon(ArgDefineCommon);
   1056   pConfig.options().setNewDTags(ArgEnableNewDTags);
   1057   pConfig.options().setHashStyle(ArgHashStyle);
   1058   pConfig.options().setNoStdlib(ArgNoStdlib);
   1059 
   1060   if (ArgStripAll)
   1061     pConfig.options().setStripSymbols(mcld::GeneralOptions::StripAllSymbols);
   1062   else if (ArgDiscardAll)
   1063     pConfig.options().setStripSymbols(mcld::GeneralOptions::StripLocals);
   1064   else if (ArgDiscardLocals)
   1065     pConfig.options().setStripSymbols(mcld::GeneralOptions::StripTemporaries);
   1066   else
   1067     pConfig.options().setStripSymbols(mcld::GeneralOptions::KeepAllSymbols);
   1068 
   1069   // set up rename map, for --wrap
   1070   cl::list<std::string>::iterator wname;
   1071   cl::list<std::string>::iterator wnameEnd = ArgWrapList.end();
   1072   for (wname = ArgWrapList.begin(); wname != wnameEnd; ++wname) {
   1073     bool exist = false;
   1074 
   1075     // add wname -> __wrap_wname
   1076     mcld::StringEntry<llvm::StringRef>* to_wrap =
   1077                     pConfig.scripts().renameMap().insert(*wname, exist);
   1078 
   1079     std::string to_wrap_str = "__wrap_" + *wname;
   1080     to_wrap->setValue(to_wrap_str);
   1081 
   1082     if (exist)
   1083       mcld::warning(mcld::diag::rewrap) << *wname << to_wrap_str;
   1084 
   1085     // add __real_wname -> wname
   1086     std::string from_real_str = "__real_" + *wname;
   1087     mcld::StringEntry<llvm::StringRef>* from_real =
   1088              pConfig.scripts().renameMap().insert(from_real_str, exist);
   1089     from_real->setValue(*wname);
   1090     if (exist)
   1091       mcld::warning(mcld::diag::rewrap) << *wname << from_real_str;
   1092   } // end of for
   1093 
   1094   // set up rename map, for --portable
   1095   cl::list<std::string>::iterator pname;
   1096   cl::list<std::string>::iterator pnameEnd = ArgPortList.end();
   1097   for (pname = ArgPortList.begin(); pname != pnameEnd; ++pname) {
   1098     bool exist = false;
   1099 
   1100     // add pname -> pname_portable
   1101     mcld::StringEntry<llvm::StringRef>* to_port =
   1102                   pConfig.scripts().renameMap().insert(*pname, exist);
   1103 
   1104     std::string to_port_str = *pname + "_portable";
   1105     to_port->setValue(to_port_str);
   1106 
   1107     if (exist)
   1108       mcld::warning(mcld::diag::rewrap) << *pname << to_port_str;
   1109 
   1110     // add __real_pname -> pname
   1111     std::string from_real_str = "__real_" + *pname;
   1112     mcld::StringEntry<llvm::StringRef>* from_real =
   1113              pConfig.scripts().renameMap().insert(from_real_str, exist);
   1114 
   1115     from_real->setValue(*pname);
   1116     if (exist)
   1117       mcld::warning(mcld::diag::rewrap) << *pname << from_real_str;
   1118   } // end of for
   1119 
   1120   // add -z options
   1121   cl::list<mcld::ZOption>::iterator zOpt;
   1122   cl::list<mcld::ZOption>::iterator zOptEnd = ArgZOptionList.end();
   1123   for (zOpt = ArgZOptionList.begin(); zOpt != zOptEnd; ++zOpt) {
   1124     pConfig.options().addZOption(*zOpt);
   1125   }
   1126 
   1127   if (ArgGCSections) {
   1128     mcld::warning(mcld::diag::warn_unsupported_option) << ArgGCSections.ArgStr;
   1129   }
   1130 
   1131   // set up icf mode
   1132   switch (ArgICF) {
   1133     case icf::None:
   1134       break;
   1135     case icf::All:
   1136     case icf::Safe:
   1137     default:
   1138       mcld::warning(mcld::diag::warn_unsupported_option) << ArgICF.ArgStr;
   1139       break;
   1140   }
   1141 
   1142   if (ArgFIXCA8) {
   1143     mcld::warning(mcld::diag::warn_unsupported_option) << ArgFIXCA8.ArgStr;
   1144   }
   1145 
   1146   // add address mappings
   1147   // -Ttext
   1148   if (-1U != ArgTextSegAddr) {
   1149     bool exist = false;
   1150     mcld::StringEntry<uint64_t>* text_mapping =
   1151       pConfig.scripts().addressMap().insert(".text", exist);
   1152     text_mapping->setValue(ArgTextSegAddr);
   1153   }
   1154   // -Tdata
   1155   if (-1U != ArgDataSegAddr) {
   1156     bool exist = false;
   1157     mcld::StringEntry<uint64_t>* data_mapping =
   1158       pConfig.scripts().addressMap().insert(".data", exist);
   1159     data_mapping->setValue(ArgDataSegAddr);
   1160   }
   1161   // -Tbss
   1162   if (-1U != ArgBssSegAddr) {
   1163     bool exist = false;
   1164     mcld::StringEntry<uint64_t>* bss_mapping =
   1165       pConfig.scripts().addressMap().insert(".bss", exist);
   1166     bss_mapping->setValue(ArgBssSegAddr);
   1167   }
   1168   // --section-start SECTION=ADDRESS
   1169   for (cl::list<std::string>::iterator
   1170          it = ArgAddressMapList.begin(), ie = ArgAddressMapList.end();
   1171        it != ie; ++it) {
   1172     // FIXME: Add a cl::parser
   1173     size_t pos = (*it).find_last_of('=');
   1174     llvm::StringRef script(*it);
   1175     uint64_t address = 0x0;
   1176     script.substr(pos + 1).getAsInteger(0, address);
   1177     bool exist = false;
   1178     mcld::StringEntry<uint64_t>* addr_mapping =
   1179       pConfig.scripts().addressMap().insert(script.substr(0, pos), exist);
   1180     addr_mapping->setValue(address);
   1181   }
   1182 
   1183   // set up filter/aux filter for shared object
   1184   pConfig.options().setFilter(ArgFilter);
   1185 
   1186   cl::list<std::string>::iterator aux;
   1187   cl::list<std::string>::iterator auxEnd = ArgAuxiliary.end();
   1188   for (aux = ArgAuxiliary.begin(); aux != auxEnd; ++aux)
   1189     pConfig.options().getAuxiliaryList().push_back(*aux);
   1190 
   1191   return true;
   1192 }
   1193 
   1194 int main(int argc, char* argv[])
   1195 {
   1196   LLVMContext &Context = getGlobalContext();
   1197   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
   1198 
   1199   // Initialize targets first, so that --version shows registered targets.
   1200   InitializeAllTargets();
   1201   InitializeAllAsmPrinters();
   1202   InitializeAllAsmParsers();
   1203   InitializeAllTargetMCs();
   1204   mcld::InitializeAllTargets();
   1205   mcld::InitializeAllLinkers();
   1206   mcld::InitializeAllEmulations();
   1207   mcld::InitializeAllDiagnostics();
   1208 
   1209   ParseProgName(argv[0]);
   1210   cl::ParseCommandLineOptions(argc, argv, "MCLinker\n");
   1211 
   1212 #ifdef ENABLE_UNITTEST
   1213   if (UnitTest) {
   1214     return unit_test( argc, argv );
   1215   }
   1216 #endif
   1217 
   1218   // Load the module to be compiled...
   1219   std::auto_ptr<llvm::Module> M;
   1220 
   1221   // Load the module to be linked...
   1222   mcld::Module LDIRModule;
   1223 
   1224   mcld::LinkerConfig LDConfig;
   1225 
   1226   // Process the linker input from the command line
   1227   if (!ProcessLinkerOptionsFromCommand(LDConfig)) {
   1228     errs() << argv[0] << ": failed to process linker options from command line!\n";
   1229     return 1;
   1230   }
   1231 
   1232   if (ArgBitcodeFilename.empty() &&
   1233       (mcld::CGFT_DSOFile != ArgFileType &&
   1234        mcld::CGFT_EXEFile != ArgFileType &&
   1235        mcld::CGFT_PARTIAL != ArgFileType &&
   1236        mcld::CGFT_BINARY  != ArgFileType)) {
   1237     // If the file is not given, forcefully read from stdin
   1238     if (ArgVerbose >= 0) {
   1239       errs() << "** The bitcode/llvm asm file is not given. Read from stdin.\n"
   1240              << "** Specify input bitcode/llvm asm file by\n\n"
   1241              << "          llvm-mcld -dB [the bitcode/llvm asm]\n\n";
   1242     }
   1243 
   1244     ArgBitcodeFilename.assign("-");
   1245   }
   1246 
   1247   if (!ArgBitcodeFilename.empty()) {
   1248     SMDiagnostic Err;
   1249     M.reset(ParseIRFile(ArgBitcodeFilename.native(), Err, Context));
   1250 
   1251     if (M.get() == 0) {
   1252       Err.print(argv[0], errs());
   1253       errs() << "** Failed to to the given bitcode/llvm asm file '"
   1254              << ArgBitcodeFilename.native() << "'. **\n";
   1255       return 1;
   1256     }
   1257   }
   1258   else {
   1259     // If here, output must be dynamic shared object (mcld::CGFT_DSOFile) and
   1260     // executable file (mcld::CGFT_EXEFile).
   1261     M.reset(new Module("Empty Module", Context));
   1262   }
   1263   Module &mod = *M.get();
   1264 
   1265   // If we are supposed to override the target triple, do so now.
   1266   Triple TheTriple;
   1267   if (!TargetTriple.empty()) {
   1268     TheTriple.setTriple(TargetTriple);
   1269     mod.setTargetTriple(TargetTriple);
   1270   }
   1271 
   1272   // User doesn't specify the triple from command.
   1273   if (TheTriple.getTriple().empty()) {
   1274     // Try to get one from the input Module.
   1275     const std::string &TripleStr = mod.getTargetTriple();
   1276 
   1277     if (TripleStr.empty())
   1278       TheTriple.setTriple(sys::getDefaultTargetTriple());
   1279     else
   1280       TheTriple.setTriple(TripleStr);
   1281   }
   1282 
   1283   // Allocate target machine.  First, check whether the user has explicitly
   1284   // specified an architecture to compile for. If so we have to look it up by
   1285   // name, because it might be a backend that has no mapping to a target triple.
   1286   const mcld::Target *TheTarget = 0;
   1287   if (!MArch.empty()) {
   1288     for (mcld::TargetRegistry::iterator it = mcld::TargetRegistry::begin(),
   1289            ie = mcld::TargetRegistry::end(); it != ie; ++it) {
   1290       if (MArch == (*it)->get()->getName()) {
   1291         TheTarget = *it;
   1292         break;
   1293       }
   1294     }
   1295 
   1296     if (!TheTarget) {
   1297       errs() << argv[0] << ": error: invalid target '" << MArch << "'.\n";
   1298       return 1;
   1299     }
   1300 
   1301     // Adjust the triple to match (if known), otherwise stick with the
   1302     // module/host triple.
   1303     Triple::ArchType Type = Triple::getArchTypeForLLVMName(MArch);
   1304     if (Type != Triple::UnknownArch)
   1305       TheTriple.setArch(Type);
   1306   }
   1307   else {
   1308     std::string Err;
   1309     TheTarget = mcld::TargetRegistry::lookupTarget(TheTriple.getTriple(), Err);
   1310     if (TheTarget == 0) {
   1311       errs() << "error: auto-selecting target `" << TheTriple.getTriple()
   1312              << "'\n"
   1313              << "Please use the -march option to explicitly select a target.\n"
   1314              << "Example:\n"
   1315              << "  $ " << argv[0] << " -march=arm\n";
   1316       return 1;
   1317     }
   1318   }
   1319   // Set up mcld::LinkerConfig
   1320   LDConfig.targets().setTriple(TheTriple);
   1321 
   1322   // Package up features to be passed to target/subtarget
   1323   std::string FeaturesStr;
   1324   if (MAttrs.size()) {
   1325     SubtargetFeatures Features;
   1326     for (unsigned i = 0; i != MAttrs.size(); ++i)
   1327       Features.AddFeature(MAttrs[i]);
   1328     FeaturesStr = Features.getString();
   1329   }
   1330 
   1331   CodeGenOpt::Level OLvl = CodeGenOpt::Default;
   1332   switch (OptLevel) {
   1333   default:
   1334     errs() << argv[0] << ": invalid optimization level.\n";
   1335     return 1;
   1336   case ' ': break;
   1337   case '0': OLvl = CodeGenOpt::None; break;
   1338   case '1': OLvl = CodeGenOpt::Less; break;
   1339   case '2': OLvl = CodeGenOpt::Default; break;
   1340   case '3': OLvl = CodeGenOpt::Aggressive; break;
   1341   }
   1342 
   1343   // set -fPIC
   1344   if (ArgFPIC)
   1345     ArgRelocModel = Reloc::PIC_;
   1346 
   1347   TargetOptions Options;
   1348   Options.LessPreciseFPMADOption = EnableFPMAD;
   1349   Options.NoFramePointerElim = DisableFPElim;
   1350   Options.NoFramePointerElimNonLeaf = DisableFPElimNonLeaf;
   1351   Options.AllowFPOpFusion = FuseFPOps;
   1352   Options.UnsafeFPMath = EnableUnsafeFPMath;
   1353   Options.NoInfsFPMath = EnableNoInfsFPMath;
   1354   Options.NoNaNsFPMath = EnableNoNaNsFPMath;
   1355   Options.HonorSignDependentRoundingFPMathOption =
   1356       EnableHonorSignDependentRoundingFPMath;
   1357   Options.UseSoftFloat = GenerateSoftFloatCalls;
   1358   if (FloatABIForCalls != FloatABI::Default)
   1359     Options.FloatABIType = FloatABIForCalls;
   1360   Options.NoZerosInBSS = DontPlaceZerosInBSS;
   1361   Options.JITExceptionHandling = EnableJITExceptionHandling;
   1362   Options.JITEmitDebugInfo = EmitJitDebugInfo;
   1363   Options.JITEmitDebugInfoToDisk = EmitJitDebugInfoToDisk;
   1364   Options.GuaranteedTailCallOpt = EnableGuaranteedTailCallOpt;
   1365   Options.StackAlignmentOverride = OverrideStackAlignment;
   1366   Options.RealignStack = EnableRealignStack;
   1367   Options.TrapFuncName = TrapFuncName;
   1368   Options.EnableSegmentedStacks = SegmentedStacks;
   1369 
   1370   std::auto_ptr<mcld::MCLDTargetMachine> target_machine(
   1371           TheTarget->createTargetMachine(TheTriple.getTriple(),
   1372                                          MCPU, FeaturesStr, Options,
   1373                                          ArgRelocModel, CMModel, OLvl));
   1374   assert(target_machine.get() && "Could not allocate target machine!");
   1375   mcld::MCLDTargetMachine &TheTargetMachine = *target_machine.get();
   1376 
   1377   TheTargetMachine.getTM().setMCUseLoc(false);
   1378   TheTargetMachine.getTM().setMCUseCFI(false);
   1379 
   1380   // FIXME: Move the initialization of LineInfo to mcld::Linker when we
   1381   // finish LineInfo's implementation.
   1382   OwningPtr<mcld::DiagnosticLineInfo>
   1383     diag_line_info(TheTarget->createDiagnosticLineInfo(*TheTarget,
   1384                                                        TheTriple.getTriple()));
   1385 
   1386   mcld::getDiagnosticEngine().setLineInfo(*diag_line_info.take());
   1387 
   1388   // Figure out where we are going to send the output...
   1389   OwningPtr<mcld::ToolOutputFile>
   1390   Out(GetOutputStream(TheTarget->get()->getName(),
   1391                       TheTriple.getOS(),
   1392                       ArgFileType,
   1393                       ArgBitcodeFilename,
   1394                       ArgOutputFilename));
   1395   if (!Out) {
   1396     // FIXME: show some error message pls.
   1397     return 1;
   1398   }
   1399 
   1400   // Build up all of the passes that we want to do to the module.
   1401   PassManager PM;
   1402 
   1403   // Add the data layout from the target machine, if it exists, or the module.
   1404   if (const DataLayout *DL = TheTargetMachine.getTM().getDataLayout())
   1405     PM.add(new DataLayout(*DL));
   1406    else
   1407     PM.add(new DataLayout(&mod));
   1408 
   1409   // Override default to generate verbose assembly.
   1410   TheTargetMachine.getTM().setAsmVerbosityDefault(true);
   1411 
   1412   {
   1413     // Ask the target to add backend passes as necessary.
   1414     if( TheTargetMachine.addPassesToEmitFile(PM,
   1415                                              *Out,
   1416                                              ArgFileType,
   1417                                              OLvl,
   1418                                              LDIRModule,
   1419                                              LDConfig,
   1420                                              NoVerify)) {
   1421       errs() << argv[0] << ": target does not support generation of this"
   1422              << " file type!\n";
   1423       return 1;
   1424     }
   1425 
   1426     // Before executing passes, print the final values of the LLVM options.
   1427     cl::PrintOptionValues();
   1428 
   1429     PM.run(mod);
   1430   }
   1431 
   1432   if (mcld::getDiagnosticEngine().getPrinter()->getNumErrors())
   1433     return 1;
   1434 
   1435   // Declare success.
   1436   Out->keep();
   1437   return 0;
   1438 }
   1439 
   1440