Merge clang, llvm, lld, lldb, compiler-rt and libc++ 5.0.0 release.

MFC r309126 (by emaste):

  Correct lld llvm-tblgen dependency file name

MFC r309169:

  Get rid of separate Subversion mergeinfo properties for llvm-dwarfdump
  and llvm-lto.  The mergeinfo confuses Subversion enormously, and these
  directories will just use the mergeinfo for llvm itself.

MFC r312765:

  Pull in r276136 from upstream llvm trunk (by Wei Mi):

    Use ValueOffsetPair to enhance value reuse during SCEV expansion.

    In D12090, the ExprValueMap was added to reuse existing value during
    SCEV expansion. However, const folding and sext/zext distribution can
    make the reuse still difficult.

    A simplified case is: suppose we know S1 expands to V1 in
    ExprValueMap, and
      S1 = S2 + C_a
      S3 = S2 + C_b
    where C_a and C_b are different SCEVConstants. Then we'd like to
    expand S3 as V1 - C_a + C_b instead of expanding S2 literally. It is
    helpful when S2 is a complex SCEV expr and S2 has no entry in
    ExprValueMap, which is usually caused by the fact that S3 is
    generated from S1 after const folding.

    In order to do that, we represent ExprValueMap as a mapping from SCEV
    to ValueOffsetPair. We will save both S1->{V1, 0} and S2->{V1, C_a}
    into the ExprValueMap when we create SCEV for V1. When S3 is
    expanded, it will first expand S2 to V1 - C_a because of S2->{V1,
    C_a} in the map, then expand S3 to V1 - C_a + C_b.

    Differential Revision: https://reviews.llvm.org/D21313

  This should fix assertion failures when building OpenCV >= 3.1.

  PR:		215649

MFC r312831:

  Revert r312765 for now, since it causes assertions when building
  lang/spidermonkey24.

  Reported by:	antoine
  PR:		215649

MFC r316511 (by jhb):

  Add an implementation of __ffssi2() derived from __ffsdi2().

  Newer versions of GCC include an __ffssi2() symbol in libgcc and the
  compiler can emit calls to it in generated code.  This is true for at
  least GCC 6.2 when compiling world for mips and mips64.

  Reviewed by:	jmallett, dim
  Sponsored by:	DARPA / AFRL
  Differential Revision:	https://reviews.freebsd.org/D10086

MFC r318601 (by adrian):

  [libcompiler-rt] add bswapdi2/bswapsi2

  This is required for mips gcc 6.3 userland to build/run.

  Reviewed by:	emaste, dim
  Approved by:	emaste
  Differential Revision:	https://reviews.freebsd.org/D10838

MFC r318884 (by emaste):

  lldb: map TRAP_CAP to a trace trap

  In the absense of a more specific handler for TRAP_CAP (generated by
  ENOTCAPABLE or ECAPMODE while in capability mode) treat it as a trace
  trap.

  Example usage (testing the bug in PR219173):

  % proccontrol -m trapcap lldb usr.bin/hexdump/obj/hexdump -- -Cv -s 1 /bin/ls
  ...
  (lldb) run
  Process 12980 launching
  Process 12980 launched: '.../usr.bin/hexdump/obj/hexdump' (x86_64)
  Process 12980 stopped
  * thread #1, stop reason = trace
      frame #0: 0x0000004b80c65f1a libc.so.7`__sys_lseek + 10
  ...

  In the future we should have LLDB control the trapcap procctl itself
  (as it does with ASLR), as well as report a specific stop reason.
  This change eliminates an assertion failure from LLDB for now.

MFC r319796:

  Remove a few unneeded files from libllvm, libclang and liblldb.

MFC r319885 (by emaste):

  lld: ELF: Fix ICF crash on absolute symbol relocations.

  If two sections contained relocations to absolute symbols with the same
  value we would crash when trying to access their sections. Add a check that
  both symbols point to sections before accessing their sections, and treat
  absolute symbols as equal if their values are equal.

  Obtained from:	LLD commit r292578

MFC r319918:

  Revert r319796 for now, it can cause undefined references when linking
  in some circumstances.

  Reported by:	Shawn Webb <shawn.webb@hardenedbsd.org>

MFC r319957 (by emaste):

  lld: Add armelf emulation mode

  Obtained from:	LLD r305375

MFC r321369:

  Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
  5.0.0 (trunk r308421).  Upstream has branched for the 5.0.0 release,
  which should be in about a month.  Please report bugs and regressions,
  so we can get them into the release.

  Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
  support to build; see UPDATING for more information.

MFC r321420:

  Add a few more object files to liblldb, which should solve errors when
  linking the lldb executable in some cases.  In particular, when the
  -ffunction-sections -fdata-sections options are turned off, or
  ineffective.

  Reported by:	Shawn Webb, Mark Millard

MFC r321433:

  Cleanup stale Options.inc files from the previous libllvm build for
  clang 4.0.0.  Otherwise, these can get included before the two newly
  generated ones (which are different) for clang 5.0.0.

  Reported by:	Mark Millard

MFC r321439 (by bdrewery):

  Move llvm Options.inc hack from r321433 for NO_CLEAN to lib/clang/libllvm.

  The files are only ever generated to .OBJDIR, not to WORLDTMP (as a
  sysroot) and are only ever included from a compilation.  So using
  a beforebuild target here removes the file before the compilation
  tries to include it.

MFC r321664:

  Pull in r308891 from upstream llvm trunk (by Benjamin Kramer):

    [CodeGenPrepare] Cut off FindAllMemoryUses if there are too many uses.

    This avoids excessive compile time. The case I'm looking at is
    Function.cpp from an old version of LLVM that still had the giant
    memcmp string matcher in it. Before r308322 this compiled in about 2
    minutes, after it, clang takes infinite* time to compile it. With
    this patch we're at 5 min, which is still bad but this is a
    pathological case.

    The cut off at 20 uses was chosen by looking at other cut-offs in LLVM
    for user scanning. It's probably too high, but does the job and is
    very unlikely to regress anything.

    Fixes PR33900.

    * I'm impatient and aborted after 15 minutes, on the bug report it was
      killed after 2h.

  Pull in r308986 from upstream llvm trunk (by Simon Pilgrim):

    [X86][CGP] Reduce memcmp() expansion to 2 load pairs (PR33914)

    D35067/rL308322 attempted to support up to 4 load pairs for memcmp
    inlining which resulted in regressions for some optimized libc memcmp
    implementations (PR33914).

    Until we can match these more optimal cases, this patch reduces the
    memcmp expansion to a maximum of 2 load pairs (which matches what we
    do for -Os).

    This patch should be considered for the 5.0.0 release branch as well

    Differential Revision: https://reviews.llvm.org/D35830

  These fix a hang (or extremely long compile time) when building older
  LLVM ports.

  Reported by:    antoine
  PR:             219139

MFC r321719:

  Pull in r309503 from upstream clang trunk (by Richard Smith):

    PR33902: Invalidate line number cache when adding more text to
    existing buffer.

    This led to crashes as the line number cache would report a bogus
    line number for a line of code, and we'd try to find a nonexistent
    column within the line when printing diagnostics.

  This fixes an assertion when building the graphics/champlain port.

  Reported by:	antoine, kwm
  PR:		219139

MFC r321723:

  Upgrade our copies of clang, llvm, lld and lldb to r309439 from the
  upstream release_50 branch.  This is just after upstream's 5.0.0-rc1.

MFC r322320:

  Upgrade our copies of clang, llvm and libc++ to r310316 from the
  upstream release_50 branch.

MFC r322326 (by emaste):

  lldb: Make i386-*-freebsd expression work on JIT path

  * Enable i386 ABI creation for freebsd
  * Added an extra argument in ABISysV_i386::PrepareTrivialCall for mmap
    syscall
  * Unlike linux, the last argument of mmap is actually 64-bit(off_t).
    This requires us to push an additional word for the higher order bits.
  * Prior to this change, ktrace dump will show mmap failures due to
    invalid argument coming from the 6th mmap argument.

  Submitted by:	Karnajit Wangkhem
  Differential Revision:	https://reviews.llvm.org/D34776

MFC r322360 (by emaste):

  lldb: Report inferior signals as signals, not exceptions, on FreeBSD

  This is the FreeBSD equivalent of LLVM r238549.

  This serves 2 purposes:

  * LLDB should handle inferior process signals SIGSEGV/SIGILL/SIGBUS/
    SIGFPE the way it is suppose to be handled. Prior to this fix these
    signals will neither create a coredump, nor exit from the debugger
    or work for signal handling scenario.
  * eInvalidCrashReason need not report "unknown crash reason" if we have
    a valid si_signo

  llvm.org/pr23699

  Patch by Karnajit Wangkhem

  Differential Revision:  https://reviews.llvm.org/D35223

  Submitted by:	Karnajit Wangkhem
  Obtained from:	LLVM r310591

MFC r322474 (by emaste):

  lld: Add `-z muldefs` option.

  Obtained from:	LLVM r310757

MFC r322740:

  Upgrade our copies of clang, llvm, lld and libc++ to r311219 from the
  upstream release_50 branch.

MFC r322855:

  Upgrade our copies of clang, llvm, lldb and compiler-rt to r311606 from
  the upstream release_50 branch.

  As of this version, lib/msun's trig test should also work correctly
  again (see bug 220989 for more information).

  PR:		220989

MFC r323112:

  Upgrade our copies of clang, llvm, lldb and compiler-rt to r312293 from
  the upstream release_50 branch.  This corresponds to 5.0.0 rc4.

  As of this version, the cad/stepcode port should now compile in a more
  reasonable time on i386 (see bug 221836 for more information).

  PR:		221836

MFC r323245:

  Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
  5.0.0 release (upstream r312559).

  Release notes for llvm, clang and lld will be available here soon:
  <http://releases.llvm.org/5.0.0/docs/ReleaseNotes.html>
  <http://releases.llvm.org/5.0.0/tools/clang/docs/ReleaseNotes.html>
  <http://releases.llvm.org/5.0.0/tools/lld/docs/ReleaseNotes.html>

  Relnotes:	yes

1 files changed, 392 insertions, 190 deletions

diff --git a/contrib/llvm/tools/clang/lib/Lex/ModuleMap.cpp b/contrib/llvm/tools/clang/lib/Lex/ModuleMap.cpp
index 1488f62..40f78ce 100644
--- a/contrib/llvm/tools/clang/lib/Lex/ModuleMap.cpp
+++ b/contrib/llvm/tools/clang/lib/Lex/ModuleMap.cpp
@@ -36,6 +36,37 @@
 #endif
 using namespace clang;
 
+Module::HeaderKind ModuleMap::headerRoleToKind(ModuleHeaderRole Role) {
+  switch ((int)Role) {
+  default: llvm_unreachable("unknown header role");
+  case NormalHeader:
+    return Module::HK_Normal;
+  case PrivateHeader:
+    return Module::HK_Private;
+  case TextualHeader:
+    return Module::HK_Textual;
+  case PrivateHeader | TextualHeader:
+    return Module::HK_PrivateTextual;
+  }
+}
+
+ModuleMap::ModuleHeaderRole
+ModuleMap::headerKindToRole(Module::HeaderKind Kind) {
+  switch ((int)Kind) {
+  case Module::HK_Normal:
+    return NormalHeader;
+  case Module::HK_Private:
+    return PrivateHeader;
+  case Module::HK_Textual:
+    return TextualHeader;
+  case Module::HK_PrivateTextual:
+    return ModuleHeaderRole(PrivateHeader | TextualHeader);
+  case Module::HK_Excluded:
+    llvm_unreachable("unexpected header kind");
+  }
+  llvm_unreachable("unknown header kind");
+}
+
 Module::ExportDecl 
 ModuleMap::resolveExport(Module *Mod, 
                          const Module::UnresolvedExportDecl &Unresolved,
@@ -84,6 +115,143 @@ Module *ModuleMap::resolveModuleId(const ModuleId &Id, Module *Mod,
   return Context;
 }
 
+/// \brief Append to \p Paths the set of paths needed to get to the 
+/// subframework in which the given module lives.
+static void appendSubframeworkPaths(Module *Mod,
+                                    SmallVectorImpl<char> &Path) {
+  // Collect the framework names from the given module to the top-level module.
+  SmallVector<StringRef, 2> Paths;
+  for (; Mod; Mod = Mod->Parent) {
+    if (Mod->IsFramework)
+      Paths.push_back(Mod->Name);
+  }
+  
+  if (Paths.empty())
+    return;
+  
+  // Add Frameworks/Name.framework for each subframework.
+  for (unsigned I = Paths.size() - 1; I != 0; --I)
+    llvm::sys::path::append(Path, "Frameworks", Paths[I-1] + ".framework");
+}
+
+const FileEntry *
+ModuleMap::findHeader(Module *M,
+                      const Module::UnresolvedHeaderDirective &Header,
+                      SmallVectorImpl<char> &RelativePathName) {
+  auto GetFile = [&](StringRef Filename) -> const FileEntry * {
+    auto *File = SourceMgr.getFileManager().getFile(Filename);
+    if (!File ||
+        (Header.Size && File->getSize() != *Header.Size) ||
+        (Header.ModTime && File->getModificationTime() != *Header.ModTime))
+      return nullptr;
+    return File;
+  };
+
+  if (llvm::sys::path::is_absolute(Header.FileName)) {
+    RelativePathName.clear();
+    RelativePathName.append(Header.FileName.begin(), Header.FileName.end());
+    return GetFile(Header.FileName);
+  }
+
+  // Search for the header file within the module's home directory.
+  auto *Directory = M->Directory;
+  SmallString<128> FullPathName(Directory->getName());
+  unsigned FullPathLength = FullPathName.size();
+
+  if (M->isPartOfFramework()) {
+    appendSubframeworkPaths(M, RelativePathName);
+    unsigned RelativePathLength = RelativePathName.size();
+
+    // Check whether this file is in the public headers.
+    llvm::sys::path::append(RelativePathName, "Headers", Header.FileName);
+    llvm::sys::path::append(FullPathName, RelativePathName);
+    if (auto *File = GetFile(FullPathName))
+      return File;
+
+    // Check whether this file is in the private headers.
+    // Ideally, private modules in the form 'FrameworkName.Private' should
+    // be defined as 'module FrameworkName.Private', and not as
+    // 'framework module FrameworkName.Private', since a 'Private.Framework'
+    // does not usually exist. However, since both are currently widely used
+    // for private modules, make sure we find the right path in both cases.
+    if (M->IsFramework && M->Name == "Private")
+      RelativePathName.clear();
+    else
+      RelativePathName.resize(RelativePathLength);
+    FullPathName.resize(FullPathLength);
+    llvm::sys::path::append(RelativePathName, "PrivateHeaders",
+                            Header.FileName);
+    llvm::sys::path::append(FullPathName, RelativePathName);
+    return GetFile(FullPathName);
+  }
+
+  // Lookup for normal headers.
+  llvm::sys::path::append(RelativePathName, Header.FileName);
+  llvm::sys::path::append(FullPathName, RelativePathName);
+  return GetFile(FullPathName);
+}
+
+void ModuleMap::resolveHeader(Module *Mod,
+                              const Module::UnresolvedHeaderDirective &Header) {
+  SmallString<128> RelativePathName;
+  if (const FileEntry *File = findHeader(Mod, Header, RelativePathName)) {
+    if (Header.IsUmbrella) {
+      const DirectoryEntry *UmbrellaDir = File->getDir();
+      if (Module *UmbrellaMod = UmbrellaDirs[UmbrellaDir])
+        Diags.Report(Header.FileNameLoc, diag::err_mmap_umbrella_clash)
+          << UmbrellaMod->getFullModuleName();
+      else
+        // Record this umbrella header.
+        setUmbrellaHeader(Mod, File, RelativePathName.str());
+    } else {
+      Module::Header H = {RelativePathName.str(), File};
+      if (Header.Kind == Module::HK_Excluded)
+        excludeHeader(Mod, H);
+      else
+        addHeader(Mod, H, headerKindToRole(Header.Kind));
+    }
+  } else if (Header.HasBuiltinHeader && !Header.Size && !Header.ModTime) {
+    // There's a builtin header but no corresponding on-disk header. Assume
+    // this was supposed to modularize the builtin header alone.
+  } else if (Header.Kind == Module::HK_Excluded) {
+    // Ignore missing excluded header files. They're optional anyway.
+  } else {
+    // If we find a module that has a missing header, we mark this module as
+    // unavailable and store the header directive for displaying diagnostics.
+    Mod->MissingHeaders.push_back(Header);
+    // A missing header with stat information doesn't make the module
+    // unavailable; this keeps our behavior consistent as headers are lazily
+    // resolved. (Such a module still can't be built though, except from
+    // preprocessed source.)
+    if (!Header.Size && !Header.ModTime)
+      Mod->markUnavailable();
+  }
+}
+
+bool ModuleMap::resolveAsBuiltinHeader(
+    Module *Mod, const Module::UnresolvedHeaderDirective &Header) {
+  if (Header.Kind == Module::HK_Excluded ||
+      llvm::sys::path::is_absolute(Header.FileName) ||
+      Mod->isPartOfFramework() || !Mod->IsSystem || Header.IsUmbrella ||
+      !BuiltinIncludeDir || BuiltinIncludeDir == Mod->Directory ||
+      !isBuiltinHeader(Header.FileName))
+    return false;
+
+  // This is a system module with a top-level header. This header
+  // may have a counterpart (or replacement) in the set of headers
+  // supplied by Clang. Find that builtin header.
+  SmallString<128> Path;
+  llvm::sys::path::append(Path, BuiltinIncludeDir->getName(), Header.FileName);
+  auto *File = SourceMgr.getFileManager().getFile(Path);
+  if (!File)
+    return false;
+
+  auto Role = headerKindToRole(Header.Kind);
+  Module::Header H = {Path.str(), File};
+  addHeader(Mod, H, Role);
+  return true;
+}
+
 ModuleMap::ModuleMap(SourceManager &SourceMgr, DiagnosticsEngine &Diags,
                      const LangOptions &LangOpts, const TargetInfo *Target,
                      HeaderSearch &HeaderInfo)
@@ -162,6 +330,7 @@ bool ModuleMap::isBuiltinHeader(StringRef FileName) {
 
 ModuleMap::HeadersMap::iterator
 ModuleMap::findKnownHeader(const FileEntry *File) {
+  resolveHeaderDirectives(File);
   HeadersMap::iterator Known = Headers.find(File);
   if (HeaderInfo.getHeaderSearchOpts().ImplicitModuleMaps &&
       Known == Headers.end() && File->getDir() == BuiltinIncludeDir &&
@@ -244,8 +413,10 @@ void ModuleMap::diagnoseHeaderInclusion(Module *RequestingModule,
   if (getTopLevelOrNull(RequestingModule) != getTopLevelOrNull(SourceModule))
     return;
 
-  if (RequestingModule)
+  if (RequestingModule) {
     resolveUses(RequestingModule, /*Complain=*/false);
+    resolveHeaderDirectives(RequestingModule);
+  }
 
   bool Excluded = false;
   Module *Private = nullptr;
@@ -427,6 +598,7 @@ ModuleMap::findOrCreateModuleForHeaderInUmbrellaDir(const FileEntry *File) {
 
 ArrayRef<ModuleMap::KnownHeader>
 ModuleMap::findAllModulesForHeader(const FileEntry *File) const {
+  resolveHeaderDirectives(File);
   auto It = Headers.find(File);
   if (It == Headers.end())
     return None;
@@ -440,6 +612,7 @@ bool ModuleMap::isHeaderInUnavailableModule(const FileEntry *Header) const {
 bool
 ModuleMap::isHeaderUnavailableInModule(const FileEntry *Header,
                                        const Module *RequestingModule) const {
+  resolveHeaderDirectives(Header);
   HeadersMap::const_iterator Known = Headers.find(Header);
   if (Known != Headers.end()) {
     for (SmallVectorImpl<KnownHeader>::const_iterator
@@ -554,16 +727,17 @@ Module *ModuleMap::lookupModuleQualified(StringRef Name, Module *Context) const{
   return Context->findSubmodule(Name);
 }
 
-std::pair<Module *, bool> 
-ModuleMap::findOrCreateModule(StringRef Name, Module *Parent, bool IsFramework,
-                              bool IsExplicit) {
+std::pair<Module *, bool> ModuleMap::findOrCreateModule(StringRef Name,
+                                                        Module *Parent,
+                                                        bool IsFramework,
+                                                        bool IsExplicit) {
   // Try to find an existing module with this name.
   if (Module *Sub = lookupModuleQualified(Name, Parent))
     return std::make_pair(Sub, false);
   
   // Create a new module with this name.
-  Module *Result = new Module(Name, SourceLocation(), Parent,
-                              IsFramework, IsExplicit, NumCreatedModules++);
+  Module *Result = new Module(Name, SourceLocation(), Parent, IsFramework,
+                              IsExplicit, NumCreatedModules++);
   if (!Parent) {
     if (LangOpts.CurrentModule == Name)
       SourceModule = Result;
@@ -580,6 +754,7 @@ Module *ModuleMap::createModuleForInterfaceUnit(SourceLocation Loc,
   auto *Result =
       new Module(Name, Loc, nullptr, /*IsFramework*/ false,
                  /*IsExplicit*/ false, NumCreatedModules++);
+  Result->Kind = Module::ModuleInterfaceUnit;
   Modules[Name] = SourceModule = Result;
 
   // Mark the main source file as being within the newly-created module so that
@@ -810,18 +985,63 @@ void ModuleMap::setUmbrellaDir(Module *Mod, const DirectoryEntry *UmbrellaDir,
   UmbrellaDirs[UmbrellaDir] = Mod;
 }
 
-static Module::HeaderKind headerRoleToKind(ModuleMap::ModuleHeaderRole Role) {
-  switch ((int)Role) {
-  default: llvm_unreachable("unknown header role");
-  case ModuleMap::NormalHeader:
-    return Module::HK_Normal;
-  case ModuleMap::PrivateHeader:
-    return Module::HK_Private;
-  case ModuleMap::TextualHeader:
-    return Module::HK_Textual;
-  case ModuleMap::PrivateHeader | ModuleMap::TextualHeader:
-    return Module::HK_PrivateTextual;
+void ModuleMap::addUnresolvedHeader(Module *Mod,
+                                    Module::UnresolvedHeaderDirective Header) {
+  // If there is a builtin counterpart to this file, add it now so it can
+  // wrap the system header.
+  if (resolveAsBuiltinHeader(Mod, Header)) {
+    // If we have both a builtin and system version of the file, the
+    // builtin version may want to inject macros into the system header, so
+    // force the system header to be treated as a textual header in this
+    // case.
+    Header.Kind = headerRoleToKind(ModuleMap::ModuleHeaderRole(
+        headerKindToRole(Header.Kind) | ModuleMap::TextualHeader));
+    Header.HasBuiltinHeader = true;
+  }
+
+  // If possible, don't stat the header until we need to. This requires the
+  // user to have provided us with some stat information about the file.
+  // FIXME: Add support for lazily stat'ing umbrella headers and excluded
+  // headers.
+  if ((Header.Size || Header.ModTime) && !Header.IsUmbrella &&
+      Header.Kind != Module::HK_Excluded) {
+    // We expect more variation in mtime than size, so if we're given both,
+    // use the mtime as the key.
+    if (Header.ModTime)
+      LazyHeadersByModTime[*Header.ModTime].push_back(Mod);
+    else
+      LazyHeadersBySize[*Header.Size].push_back(Mod);
+    Mod->UnresolvedHeaders.push_back(Header);
+    return;
   }
+
+  // We don't have stat information or can't defer looking this file up.
+  // Perform the lookup now.
+  resolveHeader(Mod, Header);
+}
+
+void ModuleMap::resolveHeaderDirectives(const FileEntry *File) const {
+  auto BySize = LazyHeadersBySize.find(File->getSize());
+  if (BySize != LazyHeadersBySize.end()) {
+    for (auto *M : BySize->second)
+      resolveHeaderDirectives(M);
+    LazyHeadersBySize.erase(BySize);
+  }
+
+  auto ByModTime = LazyHeadersByModTime.find(File->getModificationTime());
+  if (ByModTime != LazyHeadersByModTime.end()) {
+    for (auto *M : ByModTime->second)
+      resolveHeaderDirectives(M);
+    LazyHeadersByModTime.erase(ByModTime);
+  }
+}
+
+void ModuleMap::resolveHeaderDirectives(Module *Mod) const {
+  for (auto &Header : Mod->UnresolvedHeaders)
+    // This operation is logically const; we're just changing how we represent
+    // the header information for this file.
+    const_cast<ModuleMap*>(this)->resolveHeader(Mod, Header);
+  Mod->UnresolvedHeaders.clear();
 }
 
 void ModuleMap::addHeader(Module *Mod, Module::Header Header,
@@ -948,39 +1168,6 @@ bool ModuleMap::resolveConflicts(Module *Mod, bool Complain) {
   return !Mod->UnresolvedConflicts.empty();
 }
 
-Module *ModuleMap::inferModuleFromLocation(FullSourceLoc Loc) {
-  if (Loc.isInvalid())
-    return nullptr;
-
-  if (UmbrellaDirs.empty() && Headers.empty())
-    return nullptr;
-
-  // Use the expansion location to determine which module we're in.
-  FullSourceLoc ExpansionLoc = Loc.getExpansionLoc();
-  if (!ExpansionLoc.isFileID())
-    return nullptr;
-
-  const SourceManager &SrcMgr = Loc.getManager();
-  FileID ExpansionFileID = ExpansionLoc.getFileID();
-  
-  while (const FileEntry *ExpansionFile
-           = SrcMgr.getFileEntryForID(ExpansionFileID)) {
-    // Find the module that owns this header (if any).
-    if (Module *Mod = findModuleForHeader(ExpansionFile).getModule())
-      return Mod;
-    
-    // No module owns this header, so look up the inclusion chain to see if
-    // any included header has an associated module.
-    SourceLocation IncludeLoc = SrcMgr.getIncludeLoc(ExpansionFileID);
-    if (IncludeLoc.isInvalid())
-      return nullptr;
-
-    ExpansionFileID = SrcMgr.getFileID(IncludeLoc);
-  }
-
-  return nullptr;
-}
-
 //----------------------------------------------------------------------------//
 // Module map file parser
 //----------------------------------------------------------------------------//
@@ -1010,6 +1197,7 @@ namespace clang {
       RequiresKeyword,
       Star,
       StringLiteral,
+      IntegerLiteral,
       TextualKeyword,
       LBrace,
       RBrace,
@@ -1019,7 +1207,12 @@ namespace clang {
     
     unsigned Location;
     unsigned StringLength;
-    const char *StringData;
+    union {
+      // If Kind != IntegerLiteral.
+      const char *StringData;
+      // If Kind == IntegerLiteral.
+      uint64_t IntegerValue;
+    };
     
     void clear() {
       Kind = EndOfFile;
@@ -1033,9 +1226,14 @@ namespace clang {
     SourceLocation getLocation() const {
       return SourceLocation::getFromRawEncoding(Location);
     }
+
+    uint64_t getInteger() const {
+      return Kind == IntegerLiteral ? IntegerValue : 0;
+    }
     
     StringRef getString() const {
-      return StringRef(StringData, StringLength);
+      return Kind == IntegerLiteral ? StringRef()
+                                    : StringRef(StringData, StringLength);
     }
   };
 
@@ -1057,9 +1255,6 @@ namespace clang {
     /// be resolved relative to.
     const DirectoryEntry *Directory;
 
-    /// \brief The directory containing Clang-supplied headers.
-    const DirectoryEntry *BuiltinIncludeDir;
-
     /// \brief Whether this module map is in a system header directory.
     bool IsSystem;
     
@@ -1118,26 +1313,27 @@ namespace clang {
                              ModuleMap &Map,
                              const FileEntry *ModuleMapFile,
                              const DirectoryEntry *Directory,
-                             const DirectoryEntry *BuiltinIncludeDir,
                              bool IsSystem)
       : L(L), SourceMgr(SourceMgr), Target(Target), Diags(Diags), Map(Map), 
         ModuleMapFile(ModuleMapFile), Directory(Directory),
-        BuiltinIncludeDir(BuiltinIncludeDir), IsSystem(IsSystem),
-        HadError(false), ActiveModule(nullptr)
+        IsSystem(IsSystem), HadError(false), ActiveModule(nullptr)
     {
       Tok.clear();
       consumeToken();
     }
     
     bool parseModuleMapFile();
+
+    bool terminatedByDirective() { return false; }
+    SourceLocation getLocation() { return Tok.getLocation(); }
   };
 }
 
 SourceLocation ModuleMapParser::consumeToken() {
-retry:
   SourceLocation Result = Tok.getLocation();
+
+retry:
   Tok.clear();
-  
   Token LToken;
   L.LexFromRawLexer(LToken);
   Tok.Location = LToken.getLocation().getRawEncoding();
@@ -1227,12 +1423,50 @@ retry:
     Tok.StringLength = Length;
     break;
   }
+
+  case tok::numeric_constant: {
+    // We don't support any suffixes or other complications.
+    SmallString<32> SpellingBuffer;
+    SpellingBuffer.resize(LToken.getLength() + 1);
+    const char *Start = SpellingBuffer.data();
+    unsigned Length =
+        Lexer::getSpelling(LToken, Start, SourceMgr, L.getLangOpts());
+    uint64_t Value;
+    if (StringRef(Start, Length).getAsInteger(0, Value)) {
+      Diags.Report(Tok.getLocation(), diag::err_mmap_unknown_token);
+      HadError = true;
+      goto retry;
+    }
+
+    Tok.Kind = MMToken::IntegerLiteral;
+    Tok.IntegerValue = Value;
+    break;
+  }
       
   case tok::comment:
     goto retry;
-      
+
+  case tok::hash:
+    // A module map can be terminated prematurely by
+    //   #pragma clang module contents
+    // When building the module, we'll treat the rest of the file as the
+    // contents of the module.
+    {
+      auto NextIsIdent = [&](StringRef Str) -> bool {
+        L.LexFromRawLexer(LToken);
+        return !LToken.isAtStartOfLine() && LToken.is(tok::raw_identifier) &&
+               LToken.getRawIdentifier() == Str;
+      };
+      if (NextIsIdent("pragma") && NextIsIdent("clang") &&
+          NextIsIdent("module") && NextIsIdent("contents")) {
+        Tok.Kind = MMToken::EndOfFile;
+        break;
+      }
+    }
+    LLVM_FALLTHROUGH;
+
   default:
-    Diags.Report(LToken.getLocation(), diag::err_mmap_unknown_token);
+    Diags.Report(Tok.getLocation(), diag::err_mmap_unknown_token);
     HadError = true;
     goto retry;
   }
@@ -1461,7 +1695,19 @@ void ModuleMapParser::parseModuleDecl() {
   
   // Determine whether this (sub)module has already been defined.
   if (Module *Existing = Map.lookupModuleQualified(ModuleName, ActiveModule)) {
-    if (Existing->DefinitionLoc.isInvalid() && !ActiveModule) {
+    // We might see a (re)definition of a module that we already have a
+    // definition for in two cases:
+    //  - If we loaded one definition from an AST file and we've just found a
+    //    corresponding definition in a module map file, or
+    bool LoadedFromASTFile = Existing->DefinitionLoc.isInvalid();
+    //  - If we're building a (preprocessed) module and we've just loaded the
+    //    module map file from which it was created.
+    bool ParsedAsMainInput =
+        Map.LangOpts.getCompilingModule() == LangOptions::CMK_ModuleMap &&
+        Map.LangOpts.CurrentModule == ModuleName &&
+        SourceMgr.getDecomposedLoc(ModuleNameLoc).first !=
+            SourceMgr.getDecomposedLoc(Existing->DefinitionLoc).first;
+    if (!ActiveModule && (LoadedFromASTFile || ParsedAsMainInput)) {
       // Skip the module definition.
       skipUntil(MMToken::RBrace);
       if (Tok.is(MMToken::RBrace))
@@ -1680,7 +1926,8 @@ void ModuleMapParser::parseExternModuleDecl() {
         File, /*IsSystem=*/false,
         Map.HeaderInfo.getHeaderSearchOpts().ModuleMapFileHomeIsCwd
             ? Directory
-            : File->getDir(), ExternLoc);
+            : File->getDir(),
+        FileID(), nullptr, ExternLoc);
 }
 
 /// Whether to add the requirement \p Feature to the module \p M.
@@ -1768,25 +2015,6 @@ void ModuleMapParser::parseRequiresDecl() {
   } while (true);
 }
 
-/// \brief Append to \p Paths the set of paths needed to get to the 
-/// subframework in which the given module lives.
-static void appendSubframeworkPaths(Module *Mod,
-                                    SmallVectorImpl<char> &Path) {
-  // Collect the framework names from the given module to the top-level module.
-  SmallVector<StringRef, 2> Paths;
-  for (; Mod; Mod = Mod->Parent) {
-    if (Mod->IsFramework)
-      Paths.push_back(Mod->Name);
-  }
-  
-  if (Paths.empty())
-    return;
-  
-  // Add Frameworks/Name.framework for each subframework.
-  for (unsigned I = Paths.size() - 1; I != 0; --I)
-    llvm::sys::path::append(Path, "Frameworks", Paths[I-1] + ".framework");
-}
-
 /// \brief Parse a header declaration.
 ///
 ///   header-declaration:
@@ -1839,119 +2067,75 @@ void ModuleMapParser::parseHeaderDecl(MMToken::TokenKind LeadingToken,
   Module::UnresolvedHeaderDirective Header;
   Header.FileName = Tok.getString();
   Header.FileNameLoc = consumeToken();
-  
+  Header.IsUmbrella = LeadingToken == MMToken::UmbrellaKeyword;
+  Header.Kind =
+      (LeadingToken == MMToken::ExcludeKeyword ? Module::HK_Excluded
+                                               : Map.headerRoleToKind(Role));
+
   // Check whether we already have an umbrella.
-  if (LeadingToken == MMToken::UmbrellaKeyword && ActiveModule->Umbrella) {
+  if (Header.IsUmbrella && ActiveModule->Umbrella) {
     Diags.Report(Header.FileNameLoc, diag::err_mmap_umbrella_clash)
       << ActiveModule->getFullModuleName();
     HadError = true;
     return;
   }
 
-  // Look for this file.
-  const FileEntry *File = nullptr;
-  const FileEntry *BuiltinFile = nullptr;
-  SmallString<128> RelativePathName;
-  if (llvm::sys::path::is_absolute(Header.FileName)) {
-    RelativePathName = Header.FileName;
-    File = SourceMgr.getFileManager().getFile(RelativePathName);
-  } else {
-    // Search for the header file within the search directory.
-    SmallString<128> FullPathName(Directory->getName());
-    unsigned FullPathLength = FullPathName.size();
-    
-    if (ActiveModule->isPartOfFramework()) {
-      appendSubframeworkPaths(ActiveModule, RelativePathName);
-      
-      // Check whether this file is in the public headers.
-      llvm::sys::path::append(RelativePathName, "Headers", Header.FileName);
-      llvm::sys::path::append(FullPathName, RelativePathName);
-      File = SourceMgr.getFileManager().getFile(FullPathName);
-      
-      if (!File) {
-        // Check whether this file is in the private headers.
-        // FIXME: Should we retain the subframework paths here?
-        RelativePathName.clear();
-        FullPathName.resize(FullPathLength);
-        llvm::sys::path::append(RelativePathName, "PrivateHeaders",
-                                Header.FileName);
-        llvm::sys::path::append(FullPathName, RelativePathName);
-        File = SourceMgr.getFileManager().getFile(FullPathName);
-      }
-    } else {
-      // Lookup for normal headers.
-      llvm::sys::path::append(RelativePathName, Header.FileName);
-      llvm::sys::path::append(FullPathName, RelativePathName);
-      File = SourceMgr.getFileManager().getFile(FullPathName);
-
-      // If this is a system module with a top-level header, this header
-      // may have a counterpart (or replacement) in the set of headers
-      // supplied by Clang. Find that builtin header.
-      if (ActiveModule->IsSystem && LeadingToken != MMToken::UmbrellaKeyword &&
-          BuiltinIncludeDir && BuiltinIncludeDir != Directory &&
-          ModuleMap::isBuiltinHeader(Header.FileName)) {
-        SmallString<128> BuiltinPathName(BuiltinIncludeDir->getName());
-        llvm::sys::path::append(BuiltinPathName, Header.FileName);
-        BuiltinFile = SourceMgr.getFileManager().getFile(BuiltinPathName);
-
-        // If Clang supplies this header but the underlying system does not,
-        // just silently swap in our builtin version. Otherwise, we'll end
-        // up adding both (later).
-        if (BuiltinFile && !File) {
-          File = BuiltinFile;
-          RelativePathName = BuiltinPathName;
-          BuiltinFile = nullptr;
+  // If we were given stat information, parse it so we can skip looking for
+  // the file.
+  if (Tok.is(MMToken::LBrace)) {
+    SourceLocation LBraceLoc = consumeToken();
+
+    while (!Tok.is(MMToken::RBrace) && !Tok.is(MMToken::EndOfFile)) {
+      enum Attribute { Size, ModTime, Unknown };
+      StringRef Str = Tok.getString();
+      SourceLocation Loc = consumeToken();
+      switch (llvm::StringSwitch<Attribute>(Str)
+                  .Case("size", Size)
+                  .Case("mtime", ModTime)
+                  .Default(Unknown)) {
+      case Size:
+        if (Header.Size)
+          Diags.Report(Loc, diag::err_mmap_duplicate_header_attribute) << Str;
+        if (!Tok.is(MMToken::IntegerLiteral)) {
+          Diags.Report(Tok.getLocation(),
+                       diag::err_mmap_invalid_header_attribute_value) << Str;
+          skipUntil(MMToken::RBrace);
+          break;
         }
-      }
-    }
-  }
+        Header.Size = Tok.getInteger();
+        consumeToken();
+        break;
 
-  // FIXME: We shouldn't be eagerly stat'ing every file named in a module map.
-  // Come up with a lazy way to do this.
-  if (File) {
-    if (LeadingToken == MMToken::UmbrellaKeyword) {
-      const DirectoryEntry *UmbrellaDir = File->getDir();
-      if (Module *UmbrellaModule = Map.UmbrellaDirs[UmbrellaDir]) {
-        Diags.Report(LeadingLoc, diag::err_mmap_umbrella_clash)
-          << UmbrellaModule->getFullModuleName();
-        HadError = true;
-      } else {
-        // Record this umbrella header.
-        Map.setUmbrellaHeader(ActiveModule, File, RelativePathName.str());
-      }
-    } else if (LeadingToken == MMToken::ExcludeKeyword) {
-      Module::Header H = {RelativePathName.str(), File};
-      Map.excludeHeader(ActiveModule, H);
-    } else {
-      // If there is a builtin counterpart to this file, add it now so it can
-      // wrap the system header.
-      if (BuiltinFile) {
-        // FIXME: Taking the name from the FileEntry is unstable and can give
-        // different results depending on how we've previously named that file
-        // in this build.
-        Module::Header H = { BuiltinFile->getName(), BuiltinFile };
-        Map.addHeader(ActiveModule, H, Role);
-
-        // If we have both a builtin and system version of the file, the
-        // builtin version may want to inject macros into the system header, so
-        // force the system header to be treated as a textual header in this
-        // case.
-        Role = ModuleMap::ModuleHeaderRole(Role | ModuleMap::TextualHeader);
-      }
+      case ModTime:
+        if (Header.ModTime)
+          Diags.Report(Loc, diag::err_mmap_duplicate_header_attribute) << Str;
+        if (!Tok.is(MMToken::IntegerLiteral)) {
+          Diags.Report(Tok.getLocation(),
+                       diag::err_mmap_invalid_header_attribute_value) << Str;
+          skipUntil(MMToken::RBrace);
+          break;
+        }
+        Header.ModTime = Tok.getInteger();
+        consumeToken();
+        break;
 
-      // Record this header.
-      Module::Header H = { RelativePathName.str(), File };
-      Map.addHeader(ActiveModule, H, Role);
+      case Unknown:
+        Diags.Report(Loc, diag::err_mmap_expected_header_attribute);
+        skipUntil(MMToken::RBrace);
+        break;
+      }
     }
-  } else if (LeadingToken != MMToken::ExcludeKeyword) {
-    // Ignore excluded header files. They're optional anyway.
 
-    // If we find a module that has a missing header, we mark this module as
-    // unavailable and store the header directive for displaying diagnostics.
-    Header.IsUmbrella = LeadingToken == MMToken::UmbrellaKeyword;
-    ActiveModule->markUnavailable();
-    ActiveModule->MissingHeaders.push_back(Header);
+    if (Tok.is(MMToken::RBrace))
+      consumeToken();
+    else {
+      Diags.Report(Tok.getLocation(), diag::err_mmap_expected_rbrace);
+      Diags.Report(LBraceLoc, diag::note_mmap_lbrace_match);
+      HadError = true;
+    }
   }
+
+  Map.addUnresolvedHeader(ActiveModule, std::move(Header));
 }
 
 static int compareModuleHeaders(const Module::Header *A,
@@ -1995,9 +2179,8 @@ void ModuleMapParser::parseUmbrellaDirDecl(SourceLocation UmbrellaLoc) {
   }
   
   if (!Dir) {
-    Diags.Report(DirNameLoc, diag::err_mmap_umbrella_dir_not_found)
+    Diags.Report(DirNameLoc, diag::warn_mmap_umbrella_dir_not_found)
       << DirName;
-    HadError = true;
     return;
   }
 
@@ -2503,6 +2686,7 @@ bool ModuleMapParser::parseModuleMapFile() {
     case MMToken::RequiresKeyword:
     case MMToken::Star:
     case MMToken::StringLiteral:
+    case MMToken::IntegerLiteral:
     case MMToken::TextualKeyword:
     case MMToken::UmbrellaKeyword:
     case MMToken::UseKeyword:
@@ -2515,28 +2699,46 @@ bool ModuleMapParser::parseModuleMapFile() {
 }
 
 bool ModuleMap::parseModuleMapFile(const FileEntry *File, bool IsSystem,
-                                   const DirectoryEntry *Dir,
+                                   const DirectoryEntry *Dir, FileID ID,
+                                   unsigned *Offset,
                                    SourceLocation ExternModuleLoc) {
+  assert(Target && "Missing target information");
   llvm::DenseMap<const FileEntry *, bool>::iterator Known
     = ParsedModuleMap.find(File);
   if (Known != ParsedModuleMap.end())
     return Known->second;
 
+  // If the module map file wasn't already entered, do so now.
+  if (ID.isInvalid()) {
+    auto FileCharacter =
+        IsSystem ? SrcMgr::C_System_ModuleMap : SrcMgr::C_User_ModuleMap;
+    ID = SourceMgr.createFileID(File, ExternModuleLoc, FileCharacter);
+  }
+
   assert(Target && "Missing target information");
-  auto FileCharacter = IsSystem ? SrcMgr::C_System : SrcMgr::C_User;
-  FileID ID = SourceMgr.createFileID(File, ExternModuleLoc, FileCharacter);
   const llvm::MemoryBuffer *Buffer = SourceMgr.getBuffer(ID);
   if (!Buffer)
     return ParsedModuleMap[File] = true;
+  assert((!Offset || *Offset <= Buffer->getBufferSize()) &&
+         "invalid buffer offset");
 
   // Parse this module map file.
-  Lexer L(ID, SourceMgr.getBuffer(ID), SourceMgr, MMapLangOpts);
+  Lexer L(SourceMgr.getLocForStartOfFile(ID), MMapLangOpts,
+          Buffer->getBufferStart(),
+          Buffer->getBufferStart() + (Offset ? *Offset : 0),
+          Buffer->getBufferEnd());
   SourceLocation Start = L.getSourceLocation();
   ModuleMapParser Parser(L, SourceMgr, Target, Diags, *this, File, Dir,
-                         BuiltinIncludeDir, IsSystem);
+                         IsSystem);
   bool Result = Parser.parseModuleMapFile();
   ParsedModuleMap[File] = Result;
 
+  if (Offset) {
+    auto Loc = SourceMgr.getDecomposedLoc(Parser.getLocation());
+    assert(Loc.first == ID && "stopped in a different file?");
+    *Offset = Loc.second;
+  }
+
   // Notify callbacks that we parsed it.
   for (const auto &Cb : Callbacks)
     Cb->moduleMapFileRead(Start, *File, IsSystem);