lib/Driver/Compilation.cpp - platform/external/clang - Git at Google

 //===--- Compilation.cpp - Compilation Task Implementation ----------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//

 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Action.h"
 #include "clang/Driver/ArgList.h"
 #include "clang/Driver/Driver.h"
 #include "clang/Driver/DriverDiagnostic.h"
 #include "clang/Driver/Options.h"
 #include "clang/Driver/ToolChain.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Support/Program.h"
 #include "llvm/Support/raw_ostream.h"
 #include <errno.h>
 #include <sys/stat.h>

 using namespace clang::driver;
 using namespace clang;

 Compilation::Compilation(const Driver &D, const ToolChain &_DefaultToolChain,
                          InputArgList *_Args, DerivedArgList *_TranslatedArgs)
   : TheDriver(D), DefaultToolChain(_DefaultToolChain), Args(_Args),
     TranslatedArgs(_TranslatedArgs), Redirects(0) {
 }

 Compilation::~Compilation() {
   delete TranslatedArgs;
   delete Args;

   // Free any derived arg lists.
   for (llvm::DenseMap<std::pair<const ToolChain*, const char*>,
                       DerivedArgList*>::iterator it = TCArgs.begin(),
          ie = TCArgs.end(); it != ie; ++it)
     if (it->second != TranslatedArgs)
       delete it->second;

   // Free the actions, if built.
   for (ActionList::iterator it = Actions.begin(), ie = Actions.end();
        it != ie; ++it)
     delete *it;

   // Free redirections of stdout/stderr.
   if (Redirects) {
     delete Redirects[1];
     delete Redirects[2];
     delete [] Redirects;
   }
 }

 const DerivedArgList &Compilation::getArgsForToolChain(const ToolChain *TC,
                                                        const char *BoundArch) {
   if (!TC)
     TC = &DefaultToolChain;

   DerivedArgList *&Entry = TCArgs[std::make_pair(TC, BoundArch)];
   if (!Entry) {
     Entry = TC->TranslateArgs(*TranslatedArgs, BoundArch);
     if (!Entry)
       Entry = TranslatedArgs;
   }

   return *Entry;
 }

 void Compilation::PrintJob(raw_ostream &OS, const Job &J,
                            const char *Terminator, bool Quote) const {
   if (const Command *C = dyn_cast<Command>(&J)) {
     OS << " \"" << C->getExecutable() << '"';
     for (ArgStringList::const_iterator it = C->getArguments().begin(),
            ie = C->getArguments().end(); it != ie; ++it) {
       OS << ' ';
       if (!Quote && !std::strpbrk(*it, " \"\\$")) {
         OS << *it;
         continue;
       }

       // Quote the argument and escape shell special characters; this isn't
       // really complete but is good enough.
       OS << '"';
       for (const char *s = *it; *s; ++s) {
         if (*s == '"' || *s == '\\' || *s == '$')
           OS << '\\';
         OS << *s;
       }
       OS << '"';
     }
     OS << Terminator;
   } else {
     const JobList *Jobs = cast<JobList>(&J);
     for (JobList::const_iterator
            it = Jobs->begin(), ie = Jobs->end(); it != ie; ++it)
       PrintJob(OS, **it, Terminator, Quote);
   }
 }

 static bool skipArg(const char *Flag, bool &SkipNextArg) {
   StringRef FlagRef(Flag);

   // Assume we're going to see -Flag <Arg>.
   SkipNextArg = true;

   // These flags are all of the form -Flag <Arg> and are treated as two
   // arguments.  Therefore, we need to skip the flag and the next argument.
   bool Res = llvm::StringSwitch<bool>(Flag)
     .Cases("-I", "-MF", "-MT", "-MQ", true)
     .Cases("-o", "-coverage-file", "-dependency-file", true)
     .Cases("-fdebug-compilation-dir", "-idirafter", true)
     .Cases("-include", "-include-pch", "-internal-isystem", true)
     .Cases("-internal-externc-isystem", "-iprefix", "-iwithprefix", true)
     .Cases("-iwithprefixbefore", "-isysroot", "-isystem", "-iquote", true)
     .Cases("-resource-dir", "-serialize-diagnostic-file", true)
     .Case("-dwarf-debug-flags", true)
     .Default(false);

   // Match found.
   if (Res)
     return Res;

   // The remaining flags are treated as a single argument.
   SkipNextArg = false;

   // These flags are all of the form -Flag and have no second argument.
   Res = llvm::StringSwitch<bool>(Flag)
     .Cases("-M", "-MM", "-MG", "-MP", "-MD", true)
     .Case("-MMD", true)
     .Default(false);

   // Match found.
   if (Res)
     return Res;

   // These flags are treated as a single argument (e.g., -F<Dir>).
   if (FlagRef.startswith("-F") || FlagRef.startswith("-I"))
     return true;

   return false;
 }

 static bool quoteNextArg(const char *flag) {
   return llvm::StringSwitch<bool>(flag)
     .Case("-D", true)
     .Default(false);
 }

 void Compilation::PrintDiagnosticJob(raw_ostream &OS, const Job &J) const {
   if (const Command *C = dyn_cast<Command>(&J)) {
     OS << C->getExecutable();
     unsigned QuoteNextArg = 0;
     for (ArgStringList::const_iterator it = C->getArguments().begin(),
            ie = C->getArguments().end(); it != ie; ++it) {

       bool SkipNext;
       if (skipArg(*it, SkipNext)) {
         if (SkipNext) ++it;
         continue;
       }

       if (!QuoteNextArg)
         QuoteNextArg = quoteNextArg(*it) ? 2 : 0;

       OS << ' ';

       if (QuoteNextArg == 1)
         OS << '"';

       if (!std::strpbrk(*it, " \"\\$")) {
         OS << *it;
       } else {
         // Quote the argument and escape shell special characters; this isn't
         // really complete but is good enough.
         OS << '"';
         for (const char *s = *it; *s; ++s) {
           if (*s == '"' || *s == '\\' || *s == '$')
             OS << '\\';
           OS << *s;
         }
         OS << '"';
       }

       if (QuoteNextArg) {
         if (QuoteNextArg == 1)
           OS << '"';
         --QuoteNextArg;
       }
     }
     OS << '\n';
   } else {
     const JobList *Jobs = cast<JobList>(&J);
     for (JobList::const_iterator
            it = Jobs->begin(), ie = Jobs->end(); it != ie; ++it)
       PrintDiagnosticJob(OS, **it);
   }
 }

 bool Compilation::CleanupFile(const char *File, bool IssueErrors) const {
   llvm::sys::Path P(File);
   std::string Error;

   // Don't try to remove files which we don't have write access to (but may be
   // able to remove), or non-regular files. Underlying tools may have
   // intentionally not overwritten them.
   if (!P.canWrite() || !P.isRegularFile())
     return true;

   if (P.eraseFromDisk(false, &Error)) {
     // Failure is only failure if the file exists and is "regular". There is
     // a race condition here due to the limited interface of
     // llvm::sys::Path, we want to know if the removal gave ENOENT.

     // FIXME: Grumble, P.exists() is broken. PR3837.
     struct stat buf;
     if (::stat(P.c_str(), &buf) == 0 ? (buf.st_mode & S_IFMT) == S_IFREG :
         (errno != ENOENT)) {
       if (IssueErrors)
         getDriver().Diag(clang::diag::err_drv_unable_to_remove_file)
           << Error;
       return false;
     }
   }
   return true;
 }

 bool Compilation::CleanupFileList(const ArgStringList &Files,
                                   bool IssueErrors) const {
   bool Success = true;
   for (ArgStringList::const_iterator
          it = Files.begin(), ie = Files.end(); it != ie; ++it)
     Success &= CleanupFile(*it, IssueErrors);
   return Success;
 }

 bool Compilation::CleanupFileMap(const ArgStringMap &Files,
                                  const JobAction *JA,
                                  bool IssueErrors) const {
   bool Success = true;
   for (ArgStringMap::const_iterator
          it = Files.begin(), ie = Files.end(); it != ie; ++it) {

     // If specified, only delete the files associated with the JobAction.
     // Otherwise, delete all files in the map.
     if (JA && it->first != JA)
       continue;
     Success &= CleanupFile(it->second, IssueErrors);
   }
   return Success;
 }

 int Compilation::ExecuteCommand(const Command &C,
                                 const Command *&FailingCommand) const {
   llvm::sys::Path Prog(C.getExecutable());
   const char **Argv = new const char*[C.getArguments().size() + 2];
   Argv[0] = C.getExecutable();
   std::copy(C.getArguments().begin(), C.getArguments().end(), Argv+1);
   Argv[C.getArguments().size() + 1] = 0;

   if ((getDriver().CCCEcho || getDriver().CCPrintOptions ||
        getArgs().hasArg(options::OPT_v)) && !getDriver().CCGenDiagnostics) {
     raw_ostream *OS = &llvm::errs();

     // Follow gcc implementation of CC_PRINT_OPTIONS; we could also cache the
     // output stream.
     if (getDriver().CCPrintOptions && getDriver().CCPrintOptionsFilename) {
       std::string Error;
       OS = new llvm::raw_fd_ostream(getDriver().CCPrintOptionsFilename,
                                     Error,
                                     llvm::raw_fd_ostream::F_Append);
       if (!Error.empty()) {
         getDriver().Diag(clang::diag::err_drv_cc_print_options_failure)
           << Error;
         FailingCommand = &C;
         delete OS;
         return 1;
       }
     }

     if (getDriver().CCPrintOptions)
       *OS << "[Logging clang options]";

     PrintJob(*OS, C, "\n", /*Quote=*/getDriver().CCPrintOptions);

     if (OS != &llvm::errs())
       delete OS;
   }

   std::string Error;
   int Res =
     llvm::sys::Program::ExecuteAndWait(Prog, Argv,
                                        /*env*/0, Redirects,
                                        /*secondsToWait*/0, /*memoryLimit*/0,
                                        &Error);
   if (!Error.empty()) {
     assert(Res && "Error string set with 0 result code!");
     getDriver().Diag(clang::diag::err_drv_command_failure) << Error;
   }

   if (Res)
     FailingCommand = &C;

   delete[] Argv;
   return Res;
 }

 typedef SmallVectorImpl< std::pair<int, const Command *> > FailingCommandList;

 static bool ActionFailed(const Action *A,
                          const FailingCommandList &FailingCommands) {

   if (FailingCommands.empty())
     return false;

   for (FailingCommandList::const_iterator CI = FailingCommands.begin(),
          CE = FailingCommands.end(); CI != CE; ++CI)
     if (A == &(CI->second->getSource()))
       return true;

   for (Action::const_iterator AI = A->begin(), AE = A->end(); AI != AE; ++AI)
     if (ActionFailed(*AI, FailingCommands))
       return true;

   return false;
 }

 static bool InputsOk(const Command &C,
                      const FailingCommandList &FailingCommands) {
   return !ActionFailed(&C.getSource(), FailingCommands);
 }

 void Compilation::ExecuteJob(const Job &J,
                              FailingCommandList &FailingCommands) const {
   if (const Command *C = dyn_cast<Command>(&J)) {
     if (!InputsOk(*C, FailingCommands))
       return;
     const Command *FailingCommand = 0;
     if (int Res = ExecuteCommand(*C, FailingCommand))
       FailingCommands.push_back(std::make_pair(Res, FailingCommand));
   } else {
     const JobList *Jobs = cast<JobList>(&J);
     for (JobList::const_iterator it = Jobs->begin(), ie = Jobs->end();
          it != ie; ++it)
       ExecuteJob(**it, FailingCommands);
   }
 }

 void Compilation::initCompilationForDiagnostics() {
   // Free actions and jobs.
   DeleteContainerPointers(Actions);
   Jobs.clear();

   // Clear temporary/results file lists.
   TempFiles.clear();
   ResultFiles.clear();
   FailureResultFiles.clear();

   // Remove any user specified output.  Claim any unclaimed arguments, so as
   // to avoid emitting warnings about unused args.
   OptSpecifier OutputOpts[] = { options::OPT_o, options::OPT_MD,
                                 options::OPT_MMD };
   for (unsigned i = 0, e = llvm::array_lengthof(OutputOpts); i != e; ++i) {
     if (TranslatedArgs->hasArg(OutputOpts[i]))
       TranslatedArgs->eraseArg(OutputOpts[i]);
   }
   TranslatedArgs->ClaimAllArgs();

   // Redirect stdout/stderr to /dev/null.
   Redirects = new const llvm::sys::Path*[3]();
   Redirects[1] = new const llvm::sys::Path();
   Redirects[2] = new const llvm::sys::Path();
 }

 StringRef Compilation::getSysRoot() const {
   return getDriver().SysRoot;
 }
	//===--- Compilation.cpp - Compilation Task Implementation ----------------===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//

	#include "clang/Driver/Compilation.h"
	#include "clang/Driver/Action.h"
	#include "clang/Driver/ArgList.h"
	#include "clang/Driver/Driver.h"
	#include "clang/Driver/DriverDiagnostic.h"
	#include "clang/Driver/Options.h"
	#include "clang/Driver/ToolChain.h"
	#include "llvm/ADT/STLExtras.h"
	#include "llvm/ADT/StringSwitch.h"
	#include "llvm/Support/Program.h"
	#include "llvm/Support/raw_ostream.h"
	#include <errno.h>
	#include <sys/stat.h>

	using namespace clang::driver;
	using namespace clang;

	Compilation::Compilation(const Driver &D, const ToolChain &_DefaultToolChain,
	InputArgList _Args, DerivedArgList _TranslatedArgs)
	: TheDriver(D), DefaultToolChain(_DefaultToolChain), Args(_Args),
	TranslatedArgs(_TranslatedArgs), Redirects(0) {
	}

	Compilation::~Compilation() {
	delete TranslatedArgs;
	delete Args;

	// Free any derived arg lists.
	for (llvm::DenseMap<std::pair<const ToolChain, const char>,
	DerivedArgList*>::iterator it = TCArgs.begin(),
	ie = TCArgs.end(); it != ie; ++it)
	if (it->second != TranslatedArgs)
	delete it->second;

	// Free the actions, if built.
	for (ActionList::iterator it = Actions.begin(), ie = Actions.end();
	it != ie; ++it)
	delete *it;

	// Free redirections of stdout/stderr.
	if (Redirects) {
	delete Redirects[1];
	delete Redirects[2];
	delete [] Redirects;
	}
	}

	const DerivedArgList &Compilation::getArgsForToolChain(const ToolChain *TC,
	const char *BoundArch) {
	if (!TC)
	TC = &DefaultToolChain;

	DerivedArgList *&Entry = TCArgs[std::make_pair(TC, BoundArch)];
	if (!Entry) {
	Entry = TC->TranslateArgs(*TranslatedArgs, BoundArch);
	if (!Entry)
	Entry = TranslatedArgs;
	}

	return *Entry;
	}

	void Compilation::PrintJob(raw_ostream &OS, const Job &J,
	const char *Terminator, bool Quote) const {
	if (const Command *C = dyn_cast<Command>(&J)) {
	OS << " \"" << C->getExecutable() << '"';
	for (ArgStringList::const_iterator it = C->getArguments().begin(),
	ie = C->getArguments().end(); it != ie; ++it) {
	OS << ' ';
	if (!Quote && !std::strpbrk(*it, " \"\\$")) {
	OS << *it;
	continue;
	}

	// Quote the argument and escape shell special characters; this isn't
	// really complete but is good enough.
	OS << '"';
	for (const char s = it; *s; ++s) {
	if (s == '"' \|\| s == '\\' \|\| *s == '$')
	OS << '\\';
	OS << *s;
	}
	OS << '"';
	}
	OS << Terminator;
	} else {
	const JobList *Jobs = cast<JobList>(&J);
	for (JobList::const_iterator
	it = Jobs->begin(), ie = Jobs->end(); it != ie; ++it)
	PrintJob(OS, **it, Terminator, Quote);
	}
	}

	static bool skipArg(const char *Flag, bool &SkipNextArg) {
	StringRef FlagRef(Flag);

	// Assume we're going to see -Flag <Arg>.
	SkipNextArg = true;

	// These flags are all of the form -Flag <Arg> and are treated as two
	// arguments. Therefore, we need to skip the flag and the next argument.
	bool Res = llvm::StringSwitch<bool>(Flag)
	.Cases("-I", "-MF", "-MT", "-MQ", true)
	.Cases("-o", "-coverage-file", "-dependency-file", true)
	.Cases("-fdebug-compilation-dir", "-idirafter", true)
	.Cases("-include", "-include-pch", "-internal-isystem", true)
	.Cases("-internal-externc-isystem", "-iprefix", "-iwithprefix", true)
	.Cases("-iwithprefixbefore", "-isysroot", "-isystem", "-iquote", true)
	.Cases("-resource-dir", "-serialize-diagnostic-file", true)
	.Case("-dwarf-debug-flags", true)
	.Default(false);

	// Match found.
	if (Res)
	return Res;

	// The remaining flags are treated as a single argument.
	SkipNextArg = false;

	// These flags are all of the form -Flag and have no second argument.
	Res = llvm::StringSwitch<bool>(Flag)
	.Cases("-M", "-MM", "-MG", "-MP", "-MD", true)
	.Case("-MMD", true)
	.Default(false);

	// Match found.
	if (Res)
	return Res;

	// These flags are treated as a single argument (e.g., -F<Dir>).
	if (FlagRef.startswith("-F") \|\| FlagRef.startswith("-I"))
	return true;

	return false;
	}

	static bool quoteNextArg(const char *flag) {
	return llvm::StringSwitch<bool>(flag)
	.Case("-D", true)
	.Default(false);
	}

	void Compilation::PrintDiagnosticJob(raw_ostream &OS, const Job &J) const {
	if (const Command *C = dyn_cast<Command>(&J)) {
	OS << C->getExecutable();
	unsigned QuoteNextArg = 0;
	for (ArgStringList::const_iterator it = C->getArguments().begin(),
	ie = C->getArguments().end(); it != ie; ++it) {

	bool SkipNext;
	if (skipArg(*it, SkipNext)) {
	if (SkipNext) ++it;
	continue;
	}

	if (!QuoteNextArg)
	QuoteNextArg = quoteNextArg(*it) ? 2 : 0;

	OS << ' ';

	if (QuoteNextArg == 1)
	OS << '"';

	if (!std::strpbrk(*it, " \"\\$")) {
	OS << *it;
	} else {
	// Quote the argument and escape shell special characters; this isn't
	// really complete but is good enough.
	OS << '"';
	for (const char s = it; *s; ++s) {
	if (s == '"' \|\| s == '\\' \|\| *s == '$')
	OS << '\\';
	OS << *s;
	}
	OS << '"';
	}

	if (QuoteNextArg) {
	if (QuoteNextArg == 1)
	OS << '"';
	--QuoteNextArg;
	}
	}
	OS << '\n';
	} else {
	const JobList *Jobs = cast<JobList>(&J);
	for (JobList::const_iterator
	it = Jobs->begin(), ie = Jobs->end(); it != ie; ++it)
	PrintDiagnosticJob(OS, **it);
	}
	}

	bool Compilation::CleanupFile(const char *File, bool IssueErrors) const {
	llvm::sys::Path P(File);
	std::string Error;

	// Don't try to remove files which we don't have write access to (but may be
	// able to remove), or non-regular files. Underlying tools may have
	// intentionally not overwritten them.
	if (!P.canWrite() \|\| !P.isRegularFile())
	return true;

	if (P.eraseFromDisk(false, &Error)) {
	// Failure is only failure if the file exists and is "regular". There is
	// a race condition here due to the limited interface of
	// llvm::sys::Path, we want to know if the removal gave ENOENT.

	// FIXME: Grumble, P.exists() is broken. PR3837.
	struct stat buf;
	if (::stat(P.c_str(), &buf) == 0 ? (buf.st_mode & S_IFMT) == S_IFREG :
	(errno != ENOENT)) {
	if (IssueErrors)
	getDriver().Diag(clang::diag::err_drv_unable_to_remove_file)
	<< Error;
	return false;
	}
	}
	return true;
	}

	bool Compilation::CleanupFileList(const ArgStringList &Files,
	bool IssueErrors) const {
	bool Success = true;
	for (ArgStringList::const_iterator
	it = Files.begin(), ie = Files.end(); it != ie; ++it)
	Success &= CleanupFile(*it, IssueErrors);
	return Success;
	}

	bool Compilation::CleanupFileMap(const ArgStringMap &Files,
	const JobAction *JA,
	bool IssueErrors) const {
	bool Success = true;
	for (ArgStringMap::const_iterator
	it = Files.begin(), ie = Files.end(); it != ie; ++it) {

	// If specified, only delete the files associated with the JobAction.
	// Otherwise, delete all files in the map.
	if (JA && it->first != JA)
	continue;
	Success &= CleanupFile(it->second, IssueErrors);
	}
	return Success;
	}

	int Compilation::ExecuteCommand(const Command &C,
	const Command *&FailingCommand) const {
	llvm::sys::Path Prog(C.getExecutable());
	const char *Argv = new const char[C.getArguments().size() + 2];
	Argv[0] = C.getExecutable();
	std::copy(C.getArguments().begin(), C.getArguments().end(), Argv+1);
	Argv[C.getArguments().size() + 1] = 0;

	if ((getDriver().CCCEcho \|\| getDriver().CCPrintOptions \|\|
	getArgs().hasArg(options::OPT_v)) && !getDriver().CCGenDiagnostics) {
	raw_ostream *OS = &llvm::errs();

	// Follow gcc implementation of CC_PRINT_OPTIONS; we could also cache the
	// output stream.
	if (getDriver().CCPrintOptions && getDriver().CCPrintOptionsFilename) {
	std::string Error;
	OS = new llvm::raw_fd_ostream(getDriver().CCPrintOptionsFilename,
	Error,
	llvm::raw_fd_ostream::F_Append);
	if (!Error.empty()) {
	getDriver().Diag(clang::diag::err_drv_cc_print_options_failure)
	<< Error;
	FailingCommand = &C;
	delete OS;
	return 1;
	}
	}

	if (getDriver().CCPrintOptions)
	*OS << "[Logging clang options]";

	PrintJob(OS, C, "\n", /Quote=*/getDriver().CCPrintOptions);

	if (OS != &llvm::errs())
	delete OS;
	}

	std::string Error;
	int Res =
	llvm::sys::Program::ExecuteAndWait(Prog, Argv,
	/env/0, Redirects,
	/secondsToWait/0, /memoryLimit/0,
	&Error);
	if (!Error.empty()) {
	assert(Res && "Error string set with 0 result code!");
	getDriver().Diag(clang::diag::err_drv_command_failure) << Error;
	}

	if (Res)
	FailingCommand = &C;

	delete[] Argv;
	return Res;
	}

	typedef SmallVectorImpl< std::pair<int, const Command *> > FailingCommandList;

	static bool ActionFailed(const Action *A,
	const FailingCommandList &FailingCommands) {

	if (FailingCommands.empty())
	return false;

	for (FailingCommandList::const_iterator CI = FailingCommands.begin(),
	CE = FailingCommands.end(); CI != CE; ++CI)
	if (A == &(CI->second->getSource()))
	return true;

	for (Action::const_iterator AI = A->begin(), AE = A->end(); AI != AE; ++AI)
	if (ActionFailed(*AI, FailingCommands))
	return true;

	return false;
	}

	static bool InputsOk(const Command &C,
	const FailingCommandList &FailingCommands) {
	return !ActionFailed(&C.getSource(), FailingCommands);
	}

	void Compilation::ExecuteJob(const Job &J,
	FailingCommandList &FailingCommands) const {
	if (const Command *C = dyn_cast<Command>(&J)) {
	if (!InputsOk(*C, FailingCommands))
	return;
	const Command *FailingCommand = 0;
	if (int Res = ExecuteCommand(*C, FailingCommand))
	FailingCommands.push_back(std::make_pair(Res, FailingCommand));
	} else {
	const JobList *Jobs = cast<JobList>(&J);
	for (JobList::const_iterator it = Jobs->begin(), ie = Jobs->end();
	it != ie; ++it)
	ExecuteJob(**it, FailingCommands);
	}
	}

	void Compilation::initCompilationForDiagnostics() {
	// Free actions and jobs.
	DeleteContainerPointers(Actions);
	Jobs.clear();

	// Clear temporary/results file lists.
	TempFiles.clear();
	ResultFiles.clear();
	FailureResultFiles.clear();

	// Remove any user specified output. Claim any unclaimed arguments, so as
	// to avoid emitting warnings about unused args.
	OptSpecifier OutputOpts[] = { options::OPT_o, options::OPT_MD,
	options::OPT_MMD };
	for (unsigned i = 0, e = llvm::array_lengthof(OutputOpts); i != e; ++i) {
	if (TranslatedArgs->hasArg(OutputOpts[i]))
	TranslatedArgs->eraseArg(OutputOpts[i]);
	}
	TranslatedArgs->ClaimAllArgs();

	// Redirect stdout/stderr to /dev/null.
	Redirects = new const llvm::sys::Path*[3]();
	Redirects[1] = new const llvm::sys::Path();
	Redirects[2] = new const llvm::sys::Path();
	}

	StringRef Compilation::getSysRoot() const {
	return getDriver().SysRoot;
	}