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

(cherry picked from commit 12cd91cf4c6b96a24427c0de5374916f2808d263)

1 files changed, 342 insertions, 110 deletions

diff --git a/contrib/llvm/tools/clang/lib/Parse/ParseDecl.cpp b/contrib/llvm/tools/clang/lib/Parse/ParseDecl.cpp
index 2d32087..a461069 100644
--- a/contrib/llvm/tools/clang/lib/Parse/ParseDecl.cpp
+++ b/contrib/llvm/tools/clang/lib/Parse/ParseDecl.cpp
@@ -12,7 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Parse/Parser.h"
-#include "RAIIObjectsForParser.h"
+#include "clang/Parse/RAIIObjectsForParser.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/DeclTemplate.h"
 #include "clang/Basic/AddressSpaces.h"
@@ -71,11 +71,18 @@ TypeResult Parser::ParseTypeName(SourceRange *Range,
   return Actions.ActOnTypeName(getCurScope(), DeclaratorInfo);
 }
 
+/// \brief Normalizes an attribute name by dropping prefixed and suffixed __.
+static StringRef normalizeAttrName(StringRef Name) {
+  if (Name.size() >= 4 && Name.startswith("__") && Name.endswith("__"))
+    return Name.drop_front(2).drop_back(2);
+  return Name;
+}
+
 /// isAttributeLateParsed - Return true if the attribute has arguments that
 /// require late parsing.
 static bool isAttributeLateParsed(const IdentifierInfo &II) {
 #define CLANG_ATTR_LATE_PARSED_LIST
-    return llvm::StringSwitch<bool>(II.getName())
+    return llvm::StringSwitch<bool>(normalizeAttrName(II.getName()))
 #include "clang/Parse/AttrParserStringSwitches.inc"
         .Default(false);
 #undef CLANG_ATTR_LATE_PARSED_LIST
@@ -200,13 +207,6 @@ void Parser::ParseGNUAttributes(ParsedAttributes &attrs,
   }
 }
 
-/// \brief Normalizes an attribute name by dropping prefixed and suffixed __.
-static StringRef normalizeAttrName(StringRef Name) {
-  if (Name.size() >= 4 && Name.startswith("__") && Name.endswith("__"))
-    Name = Name.drop_front(2).drop_back(2);
-  return Name;
-}
-
 /// \brief Determine whether the given attribute has an identifier argument.
 static bool attributeHasIdentifierArg(const IdentifierInfo &II) {
 #define CLANG_ATTR_IDENTIFIER_ARG_LIST
@@ -308,7 +308,9 @@ unsigned Parser::ParseAttributeArgsCommon(
     do {
       bool Uneval = attributeParsedArgsUnevaluated(*AttrName);
       EnterExpressionEvaluationContext Unevaluated(
-          Actions, Uneval ? Sema::Unevaluated : Sema::ConstantEvaluated,
+          Actions,
+          Uneval ? Sema::ExpressionEvaluationContext::Unevaluated
+                 : Sema::ExpressionEvaluationContext::ConstantEvaluated,
           /*LambdaContextDecl=*/nullptr,
           /*IsDecltype=*/false);
 
@@ -356,6 +358,10 @@ void Parser::ParseGNUAttributeArgs(IdentifierInfo *AttrName,
     ParseAvailabilityAttribute(*AttrName, AttrNameLoc, Attrs, EndLoc, ScopeName,
                                ScopeLoc, Syntax);
     return;
+  } else if (AttrKind == AttributeList::AT_ExternalSourceSymbol) {
+    ParseExternalSourceSymbolAttribute(*AttrName, AttrNameLoc, Attrs, EndLoc,
+                                       ScopeName, ScopeLoc, Syntax);
+    return;
   } else if (AttrKind == AttributeList::AT_ObjCBridgeRelated) {
     ParseObjCBridgeRelatedAttribute(*AttrName, AttrNameLoc, Attrs, EndLoc,
                                     ScopeName, ScopeLoc, Syntax);
@@ -389,6 +395,25 @@ void Parser::ParseGNUAttributeArgs(IdentifierInfo *AttrName,
                            ScopeLoc, Syntax);
 }
 
+unsigned Parser::ParseClangAttributeArgs(
+    IdentifierInfo *AttrName, SourceLocation AttrNameLoc,
+    ParsedAttributes &Attrs, SourceLocation *EndLoc, IdentifierInfo *ScopeName,
+    SourceLocation ScopeLoc, AttributeList::Syntax Syntax) {
+  assert(Tok.is(tok::l_paren) && "Attribute arg list not starting with '('");
+
+  AttributeList::Kind AttrKind =
+      AttributeList::getKind(AttrName, ScopeName, Syntax);
+
+  if (AttrKind == AttributeList::AT_ExternalSourceSymbol) {
+    ParseExternalSourceSymbolAttribute(*AttrName, AttrNameLoc, Attrs, EndLoc,
+                                       ScopeName, ScopeLoc, Syntax);
+    return Attrs.getList() ? Attrs.getList()->getNumArgs() : 0;
+  }
+
+  return ParseAttributeArgsCommon(AttrName, AttrNameLoc, Attrs, EndLoc,
+                                  ScopeName, ScopeLoc, Syntax);
+}
+
 bool Parser::ParseMicrosoftDeclSpecArgs(IdentifierInfo *AttrName,
                                         SourceLocation AttrNameLoc,
                                         ParsedAttributes &Attrs) {
@@ -1064,6 +1089,119 @@ void Parser::ParseAvailabilityAttribute(IdentifierInfo &Availability,
                Syntax, StrictLoc, ReplacementExpr.get());
 }
 
+/// \brief Parse the contents of the "external_source_symbol" attribute.
+///
+/// external-source-symbol-attribute:
+///   'external_source_symbol' '(' keyword-arg-list ')'
+///
+/// keyword-arg-list:
+///   keyword-arg
+///   keyword-arg ',' keyword-arg-list
+///
+/// keyword-arg:
+///   'language' '=' <string>
+///   'defined_in' '=' <string>
+///   'generated_declaration'
+void Parser::ParseExternalSourceSymbolAttribute(
+    IdentifierInfo &ExternalSourceSymbol, SourceLocation Loc,
+    ParsedAttributes &Attrs, SourceLocation *EndLoc, IdentifierInfo *ScopeName,
+    SourceLocation ScopeLoc, AttributeList::Syntax Syntax) {
+  // Opening '('.
+  BalancedDelimiterTracker T(*this, tok::l_paren);
+  if (T.expectAndConsume())
+    return;
+
+  // Initialize the pointers for the keyword identifiers when required.
+  if (!Ident_language) {
+    Ident_language = PP.getIdentifierInfo("language");
+    Ident_defined_in = PP.getIdentifierInfo("defined_in");
+    Ident_generated_declaration = PP.getIdentifierInfo("generated_declaration");
+  }
+
+  ExprResult Language;
+  bool HasLanguage = false;
+  ExprResult DefinedInExpr;
+  bool HasDefinedIn = false;
+  IdentifierLoc *GeneratedDeclaration = nullptr;
+
+  // Parse the language/defined_in/generated_declaration keywords
+  do {
+    if (Tok.isNot(tok::identifier)) {
+      Diag(Tok, diag::err_external_source_symbol_expected_keyword);
+      SkipUntil(tok::r_paren, StopAtSemi);
+      return;
+    }
+
+    SourceLocation KeywordLoc = Tok.getLocation();
+    IdentifierInfo *Keyword = Tok.getIdentifierInfo();
+    if (Keyword == Ident_generated_declaration) {
+      if (GeneratedDeclaration) {
+        Diag(Tok, diag::err_external_source_symbol_duplicate_clause) << Keyword;
+        SkipUntil(tok::r_paren, StopAtSemi);
+        return;
+      }
+      GeneratedDeclaration = ParseIdentifierLoc();
+      continue;
+    }
+
+    if (Keyword != Ident_language && Keyword != Ident_defined_in) {
+      Diag(Tok, diag::err_external_source_symbol_expected_keyword);
+      SkipUntil(tok::r_paren, StopAtSemi);
+      return;
+    }
+
+    ConsumeToken();
+    if (ExpectAndConsume(tok::equal, diag::err_expected_after,
+                         Keyword->getName())) {
+      SkipUntil(tok::r_paren, StopAtSemi);
+      return;
+    }
+
+    bool HadLanguage = HasLanguage, HadDefinedIn = HasDefinedIn;
+    if (Keyword == Ident_language)
+      HasLanguage = true;
+    else
+      HasDefinedIn = true;
+
+    if (Tok.isNot(tok::string_literal)) {
+      Diag(Tok, diag::err_expected_string_literal)
+          << /*Source='external_source_symbol attribute'*/ 3
+          << /*language | source container*/ (Keyword != Ident_language);
+      SkipUntil(tok::comma, tok::r_paren, StopAtSemi | StopBeforeMatch);
+      continue;
+    }
+    if (Keyword == Ident_language) {
+      if (HadLanguage) {
+        Diag(KeywordLoc, diag::err_external_source_symbol_duplicate_clause)
+            << Keyword;
+        ParseStringLiteralExpression();
+        continue;
+      }
+      Language = ParseStringLiteralExpression();
+    } else {
+      assert(Keyword == Ident_defined_in && "Invalid clause keyword!");
+      if (HadDefinedIn) {
+        Diag(KeywordLoc, diag::err_external_source_symbol_duplicate_clause)
+            << Keyword;
+        ParseStringLiteralExpression();
+        continue;
+      }
+      DefinedInExpr = ParseStringLiteralExpression();
+    }
+  } while (TryConsumeToken(tok::comma));
+
+  // Closing ')'.
+  if (T.consumeClose())
+    return;
+  if (EndLoc)
+    *EndLoc = T.getCloseLocation();
+
+  ArgsUnion Args[] = {Language.get(), DefinedInExpr.get(),
+                      GeneratedDeclaration};
+  Attrs.addNew(&ExternalSourceSymbol, SourceRange(Loc, T.getCloseLocation()),
+               ScopeName, ScopeLoc, Args, llvm::array_lengthof(Args), Syntax);
+}
+
 /// \brief Parse the contents of the "objc_bridge_related" attribute.
 /// objc_bridge_related '(' related_class ',' opt-class_method ',' opt-instance_method ')'
 /// related_class:
@@ -2414,6 +2552,7 @@ bool Parser::ParseImplicitInt(DeclSpec &DS, CXXScopeSpec *SS,
         }
       }
       // Fall through.
+      LLVM_FALLTHROUGH;
     }
     case tok::comma:
     case tok::equal:
@@ -2439,9 +2578,9 @@ bool Parser::ParseImplicitInt(DeclSpec &DS, CXXScopeSpec *SS,
   // and attempt to recover.
   ParsedType T;
   IdentifierInfo *II = Tok.getIdentifierInfo();
+  bool IsTemplateName = getLangOpts().CPlusPlus && NextToken().is(tok::less);
   Actions.DiagnoseUnknownTypeName(II, Loc, getCurScope(), SS, T,
-                                  getLangOpts().CPlusPlus &&
-                                      NextToken().is(tok::less));
+                                  IsTemplateName);
   if (T) {
     // The action has suggested that the type T could be used. Set that as
     // the type in the declaration specifiers, consume the would-be type
@@ -2466,6 +2605,13 @@ bool Parser::ParseImplicitInt(DeclSpec &DS, CXXScopeSpec *SS,
   DS.SetRangeEnd(Tok.getLocation());
   ConsumeToken();
 
+  // Eat any following template arguments.
+  if (IsTemplateName) {
+    SourceLocation LAngle, RAngle;
+    TemplateArgList Args;
+    ParseTemplateIdAfterTemplateName(true, LAngle, Args, RAngle);
+  }
+
   // TODO: Could inject an invalid typedef decl in an enclosing scope to
   // avoid rippling error messages on subsequent uses of the same type,
   // could be useful if #include was forgotten.
@@ -2483,6 +2629,8 @@ Parser::getDeclSpecContextFromDeclaratorContext(unsigned Context) {
     return DSC_class;
   if (Context == Declarator::FileContext)
     return DSC_top_level;
+  if (Context == Declarator::TemplateParamContext)
+    return DSC_template_param;
   if (Context == Declarator::TemplateTypeArgContext)
     return DSC_template_type_arg;
   if (Context == Declarator::TrailingReturnContext)
@@ -2824,48 +2972,27 @@ void Parser::ParseDeclarationSpecifiers(DeclSpec &DS,
             ->Kind == TNK_Type_template) {
         // We have a qualified template-id, e.g., N::A<int>
 
-        // C++ [class.qual]p2:
-        //   In a lookup in which the constructor is an acceptable lookup
-        //   result and the nested-name-specifier nominates a class C:
-        //
-        //     - if the name specified after the
-        //       nested-name-specifier, when looked up in C, is the
-        //       injected-class-name of C (Clause 9), or
-        //
-        //     - if the name specified after the nested-name-specifier
-        //       is the same as the identifier or the
-        //       simple-template-id's template-name in the last
-        //       component of the nested-name-specifier,
+        // If this would be a valid constructor declaration with template
+        // arguments, we will reject the attempt to form an invalid type-id
+        // referring to the injected-class-name when we annotate the token,
+        // per C++ [class.qual]p2.
         //
-        //   the name is instead considered to name the constructor of
-        //   class C.
-        //
-        // Thus, if the template-name is actually the constructor
-        // name, then the code is ill-formed; this interpretation is
-        // reinforced by the NAD status of core issue 635.
+        // To improve diagnostics for this case, parse the declaration as a
+        // constructor (and reject the extra template arguments later).
         TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Next);
         if ((DSContext == DSC_top_level || DSContext == DSC_class) &&
             TemplateId->Name &&
-            Actions.isCurrentClassName(*TemplateId->Name, getCurScope(), &SS)) {
-          if (isConstructorDeclarator(/*Unqualified*/false)) {
-            // The user meant this to be an out-of-line constructor
-            // definition, but template arguments are not allowed
-            // there.  Just allow this as a constructor; we'll
-            // complain about it later.
-            goto DoneWithDeclSpec;
-          }
-
-          // The user meant this to name a type, but it actually names
-          // a constructor with some extraneous template
-          // arguments. Complain, then parse it as a type as the user
-          // intended.
-          Diag(TemplateId->TemplateNameLoc,
-               diag::err_out_of_line_template_id_type_names_constructor)
-            << TemplateId->Name << 0 /* template name */;
+            Actions.isCurrentClassName(*TemplateId->Name, getCurScope(), &SS) &&
+            isConstructorDeclarator(/*Unqualified*/false)) {
+          // The user meant this to be an out-of-line constructor
+          // definition, but template arguments are not allowed
+          // there.  Just allow this as a constructor; we'll
+          // complain about it later.
+          goto DoneWithDeclSpec;
         }
 
         DS.getTypeSpecScope() = SS;
-        ConsumeToken(); // The C++ scope.
+        ConsumeAnnotationToken(); // The C++ scope.
         assert(Tok.is(tok::annot_template_id) &&
                "ParseOptionalCXXScopeSpecifier not working");
         AnnotateTemplateIdTokenAsType();
@@ -2874,7 +3001,7 @@ void Parser::ParseDeclarationSpecifiers(DeclSpec &DS,
 
       if (Next.is(tok::annot_typename)) {
         DS.getTypeSpecScope() = SS;
-        ConsumeToken(); // The C++ scope.
+        ConsumeAnnotationToken(); // The C++ scope.
         if (Tok.getAnnotationValue()) {
           ParsedType T = getTypeAnnotation(Tok);
           isInvalid = DS.SetTypeSpecType(DeclSpec::TST_typename,
@@ -2886,43 +3013,35 @@ void Parser::ParseDeclarationSpecifiers(DeclSpec &DS,
         else
           DS.SetTypeSpecError();
         DS.SetRangeEnd(Tok.getAnnotationEndLoc());
-        ConsumeToken(); // The typename
+        ConsumeAnnotationToken(); // The typename
       }
 
       if (Next.isNot(tok::identifier))
         goto DoneWithDeclSpec;
 
-      // If we're in a context where the identifier could be a class name,
-      // check whether this is a constructor declaration.
+      // Check whether this is a constructor declaration. If we're in a
+      // context where the identifier could be a class name, and it has the
+      // shape of a constructor declaration, process it as one.
       if ((DSContext == DSC_top_level || DSContext == DSC_class) &&
           Actions.isCurrentClassName(*Next.getIdentifierInfo(), getCurScope(),
-                                     &SS)) {
-        if (isConstructorDeclarator(/*Unqualified*/false))
-          goto DoneWithDeclSpec;
-
-        // As noted in C++ [class.qual]p2 (cited above), when the name
-        // of the class is qualified in a context where it could name
-        // a constructor, its a constructor name. However, we've
-        // looked at the declarator, and the user probably meant this
-        // to be a type. Complain that it isn't supposed to be treated
-        // as a type, then proceed to parse it as a type.
-        Diag(Next.getLocation(),
-             diag::err_out_of_line_template_id_type_names_constructor)
-          << Next.getIdentifierInfo() << 1 /* type */;
-      }
+                                     &SS) &&
+          isConstructorDeclarator(/*Unqualified*/ false))
+        goto DoneWithDeclSpec;
 
       ParsedType TypeRep =
           Actions.getTypeName(*Next.getIdentifierInfo(), Next.getLocation(),
                               getCurScope(), &SS, false, false, nullptr,
                               /*IsCtorOrDtorName=*/false,
-                              /*NonTrivialSourceInfo=*/true);
+                              /*WantNonTrivialSourceInfo=*/true,
+                              isClassTemplateDeductionContext(DSContext));
 
       // If the referenced identifier is not a type, then this declspec is
       // erroneous: We already checked about that it has no type specifier, and
       // C++ doesn't have implicit int.  Diagnose it as a typo w.r.t. to the
       // typename.
       if (!TypeRep) {
-        ConsumeToken();   // Eat the scope spec so the identifier is current.
+        // Eat the scope spec so the identifier is current.
+        ConsumeAnnotationToken();
         ParsedAttributesWithRange Attrs(AttrFactory);
         if (ParseImplicitInt(DS, &SS, TemplateInfo, AS, DSContext, Attrs)) {
           if (!Attrs.empty()) {
@@ -2935,7 +3054,7 @@ void Parser::ParseDeclarationSpecifiers(DeclSpec &DS,
       }
 
       DS.getTypeSpecScope() = SS;
-      ConsumeToken(); // The C++ scope.
+      ConsumeAnnotationToken(); // The C++ scope.
 
       isInvalid = DS.SetTypeSpecType(DeclSpec::TST_typename, Loc, PrevSpec,
                                      DiagID, TypeRep, Policy);
@@ -2965,7 +3084,7 @@ void Parser::ParseDeclarationSpecifiers(DeclSpec &DS,
         break;
 
       DS.SetRangeEnd(Tok.getAnnotationEndLoc());
-      ConsumeToken(); // The typename
+      ConsumeAnnotationToken(); // The typename
 
       continue;
     }
@@ -2996,6 +3115,31 @@ void Parser::ParseDeclarationSpecifiers(DeclSpec &DS,
       if (DS.hasTypeSpecifier())
         goto DoneWithDeclSpec;
 
+      // If the token is an identifier named "__declspec" and Microsoft
+      // extensions are not enabled, it is likely that there will be cascading
+      // parse errors if this really is a __declspec attribute. Attempt to
+      // recognize that scenario and recover gracefully.
+      if (!getLangOpts().DeclSpecKeyword && Tok.is(tok::identifier) &&
+          Tok.getIdentifierInfo()->getName().equals("__declspec")) {
+        Diag(Loc, diag::err_ms_attributes_not_enabled);
+
+        // The next token should be an open paren. If it is, eat the entire
+        // attribute declaration and continue.
+        if (NextToken().is(tok::l_paren)) {
+          // Consume the __declspec identifier.
+          ConsumeToken();
+
+          // Eat the parens and everything between them.
+          BalancedDelimiterTracker T(*this, tok::l_paren);
+          if (T.consumeOpen()) {
+            assert(false && "Not a left paren?");
+            return;
+          }
+          T.skipToEnd();
+          continue;
+        }
+      }
+
       // In C++, check to see if this is a scope specifier like foo::bar::, if
       // so handle it as such.  This is important for ctor parsing.
       if (getLangOpts().CPlusPlus) {
@@ -3029,9 +3173,10 @@ void Parser::ParseDeclarationSpecifiers(DeclSpec &DS,
         continue;
       }
 
-      ParsedType TypeRep =
-        Actions.getTypeName(*Tok.getIdentifierInfo(),
-                            Tok.getLocation(), getCurScope());
+      ParsedType TypeRep = Actions.getTypeName(
+          *Tok.getIdentifierInfo(), Tok.getLocation(), getCurScope(), nullptr,
+          false, false, nullptr, false, false,
+          isClassTemplateDeductionContext(DSContext));
 
       // If this is not a typedef name, don't parse it as part of the declspec,
       // it must be an implicit int or an error.
@@ -3054,6 +3199,16 @@ void Parser::ParseDeclarationSpecifiers(DeclSpec &DS,
           isConstructorDeclarator(/*Unqualified*/true))
         goto DoneWithDeclSpec;
 
+      // Likewise, if this is a context where the identifier could be a template
+      // name, check whether this is a deduction guide declaration.
+      if (getLangOpts().CPlusPlus1z &&
+          (DSContext == DSC_class || DSContext == DSC_top_level) &&
+          Actions.isDeductionGuideName(getCurScope(), *Tok.getIdentifierInfo(),
+                                       Tok.getLocation()) &&
+          isConstructorDeclarator(/*Unqualified*/ true,
+                                  /*DeductionGuide*/ true))
+        goto DoneWithDeclSpec;
+
       isInvalid = DS.SetTypeSpecType(DeclSpec::TST_typename, Loc, PrevSpec,
                                      DiagID, TypeRep, Policy);
       if (isInvalid)
@@ -3526,6 +3681,7 @@ void Parser::ParseDeclarationSpecifiers(DeclSpec &DS,
         isInvalid = true;
         break;
       };
+      LLVM_FALLTHROUGH;
     case tok::kw___private:
     case tok::kw___global:
     case tok::kw___local:
@@ -3951,8 +4107,8 @@ void Parser::ParseEnumSpecifier(SourceLocation StartLoc, DeclSpec &DS,
       // anything that's a simple-type-specifier followed by '(' as an
       // expression. This suffices because function types are not valid
       // underlying types anyway.
-      EnterExpressionEvaluationContext Unevaluated(Actions,
-                                                   Sema::ConstantEvaluated);
+      EnterExpressionEvaluationContext Unevaluated(
+          Actions, Sema::ExpressionEvaluationContext::ConstantEvaluated);
       TPResult TPR = isExpressionOrTypeSpecifierSimple(NextToken().getKind());
       // If the next token starts an expression, we know we're parsing a
       // bit-field. This is the common case.
@@ -4107,7 +4263,9 @@ void Parser::ParseEnumSpecifier(SourceLocation StartLoc, DeclSpec &DS,
                                    AS, DS.getModulePrivateSpecLoc(), TParams,
                                    Owned, IsDependent, ScopedEnumKWLoc,
                                    IsScopedUsingClassTag, BaseType,
-                                   DSC == DSC_type_specifier, &SkipBody);
+                                   DSC == DSC_type_specifier,
+                                   DSC == DSC_template_param ||
+                                   DSC == DSC_template_type_arg, &SkipBody);
 
   if (SkipBody.ShouldSkip) {
     assert(TUK == Sema::TUK_Definition && "can only skip a definition");
@@ -4161,8 +4319,15 @@ void Parser::ParseEnumSpecifier(SourceLocation StartLoc, DeclSpec &DS,
     return;
   }
 
-  if (Tok.is(tok::l_brace) && TUK != Sema::TUK_Reference)
-    ParseEnumBody(StartLoc, TagDecl);
+  if (Tok.is(tok::l_brace) && TUK != Sema::TUK_Reference) {
+    Decl *D = SkipBody.CheckSameAsPrevious ? SkipBody.New : TagDecl;
+    ParseEnumBody(StartLoc, D);
+    if (SkipBody.CheckSameAsPrevious &&
+        !Actions.ActOnDuplicateDefinition(DS, TagDecl, SkipBody)) {
+      DS.SetTypeSpecError();
+      return;
+    }
+  }
 
   if (DS.SetTypeSpecType(DeclSpec::TST_enum, StartLoc,
                          NameLoc.isValid() ? NameLoc : StartLoc,
@@ -4234,11 +4399,9 @@ void Parser::ParseEnumBody(SourceLocation StartLoc, Decl *EnumDecl) {
     }
 
     // Install the enumerator constant into EnumDecl.
-    Decl *EnumConstDecl = Actions.ActOnEnumConstant(getCurScope(), EnumDecl,
-                                                    LastEnumConstDecl,
-                                                    IdentLoc, Ident,
-                                                    attrs.getList(), EqualLoc,
-                                                    AssignedVal.get());
+    Decl *EnumConstDecl = Actions.ActOnEnumConstant(
+        getCurScope(), EnumDecl, LastEnumConstDecl, IdentLoc, Ident,
+        attrs.getList(), EqualLoc, AssignedVal.get());
     EnumAvailabilityDiags.back().done();
 
     EnumConstantDecls.push_back(EnumConstDecl);
@@ -4673,7 +4836,7 @@ bool Parser::isDeclarationSpecifier(bool DisambiguatingWithExpression) {
   }
 }
 
-bool Parser::isConstructorDeclarator(bool IsUnqualified) {
+bool Parser::isConstructorDeclarator(bool IsUnqualified, bool DeductionGuide) {
   TentativeParsingAction TPA(*this);
 
   // Parse the C++ scope specifier.
@@ -4685,15 +4848,21 @@ bool Parser::isConstructorDeclarator(bool IsUnqualified) {
   }
 
   // Parse the constructor name.
-  if (Tok.isOneOf(tok::identifier, tok::annot_template_id)) {
+  if (Tok.is(tok::identifier)) {
     // We already know that we have a constructor name; just consume
     // the token.
     ConsumeToken();
+  } else if (Tok.is(tok::annot_template_id)) {
+    ConsumeAnnotationToken();
   } else {
     TPA.Revert();
     return false;
   }
 
+  // There may be attributes here, appertaining to the constructor name or type
+  // we just stepped past.
+  SkipCXX11Attributes();
+
   // Current class name must be followed by a left parenthesis.
   if (Tok.isNot(tok::l_paren)) {
     TPA.Revert();
@@ -4740,7 +4909,7 @@ bool Parser::isConstructorDeclarator(bool IsUnqualified) {
     // be a constructor declaration with an invalid argument type. Keep
     // looking.
     if (Tok.is(tok::annot_cxxscope))
-      ConsumeToken();
+      ConsumeAnnotationToken();
     ConsumeToken();
 
     // If this is not a constructor, we must be parsing a declarator,
@@ -4761,13 +4930,24 @@ bool Parser::isConstructorDeclarator(bool IsUnqualified) {
 
     case tok::r_paren:
       // C(X   )
-      if (NextToken().is(tok::colon) || NextToken().is(tok::kw_try)) {
+
+      // Skip past the right-paren and any following attributes to get to
+      // the function body or trailing-return-type.
+      ConsumeParen();
+      SkipCXX11Attributes();
+
+      if (DeductionGuide) {
+        // C(X) -> ... is a deduction guide.
+        IsConstructor = Tok.is(tok::arrow);
+        break;
+      }
+      if (Tok.is(tok::colon) || Tok.is(tok::kw_try)) {
         // Assume these were meant to be constructors:
         //   C(X)   :    (the name of a bit-field cannot be parenthesized).
         //   C(X)   try  (this is otherwise ill-formed).
         IsConstructor = true;
       }
-      if (NextToken().is(tok::semi) || NextToken().is(tok::l_brace)) {
+      if (Tok.is(tok::semi) || Tok.is(tok::l_brace)) {
         // If we have a constructor name within the class definition,
         // assume these were meant to be constructors:
         //   C(X)   {
@@ -4778,7 +4958,7 @@ bool Parser::isConstructorDeclarator(bool IsUnqualified) {
         //
         // FIXME: We can actually do this whether or not the name is qualified,
         // because if it is qualified in this context it must be being used as
-        // a constructor name. However, we do not implement that rule correctly
+        // a constructor name.
         // currently, so we're somewhat conservative here.
         IsConstructor = IsUnqualified;
       }
@@ -4806,9 +4986,10 @@ bool Parser::isConstructorDeclarator(bool IsUnqualified) {
 ///              [ only if AttReqs & AR_CXX11AttributesParsed ]
 /// Note: vendor can be GNU, MS, etc and can be explicitly controlled via
 /// AttrRequirements bitmask values.
-void Parser::ParseTypeQualifierListOpt(DeclSpec &DS, unsigned AttrReqs,
-                                       bool AtomicAllowed,
-                                       bool IdentifierRequired) {
+void Parser::ParseTypeQualifierListOpt(
+    DeclSpec &DS, unsigned AttrReqs, bool AtomicAllowed,
+    bool IdentifierRequired,
+    Optional<llvm::function_ref<void()>> CodeCompletionHandler) {
   if (getLangOpts().CPlusPlus11 && (AttrReqs & AR_CXX11AttributesParsed) &&
       isCXX11AttributeSpecifier()) {
     ParsedAttributesWithRange attrs(AttrFactory);
@@ -4826,7 +5007,10 @@ void Parser::ParseTypeQualifierListOpt(DeclSpec &DS, unsigned AttrReqs,
 
     switch (Tok.getKind()) {
     case tok::code_completion:
-      Actions.CodeCompleteTypeQualifiers(DS);
+      if (CodeCompletionHandler)
+        (*CodeCompletionHandler)();
+      else
+        Actions.CodeCompleteTypeQualifiers(DS);
       return cutOffParsing();
 
     case tok::kw_const:
@@ -4872,6 +5056,7 @@ void Parser::ParseTypeQualifierListOpt(DeclSpec &DS, unsigned AttrReqs,
         if (TryKeywordIdentFallback(false))
           continue;
       }
+      LLVM_FALLTHROUGH;
     case tok::kw___sptr:
     case tok::kw___w64:
     case tok::kw___ptr64:
@@ -4921,6 +5106,7 @@ void Parser::ParseTypeQualifierListOpt(DeclSpec &DS, unsigned AttrReqs,
         continue; // do *not* consume the next token!
       }
       // otherwise, FALL THROUGH!
+      LLVM_FALLTHROUGH;
     default:
       DoneWithTypeQuals:
       // If this is not a type-qualifier token, we're done reading type
@@ -5309,21 +5495,29 @@ void Parser::ParseDirectDeclarator(Declarator &D) {
       // We found something that indicates the start of an unqualified-id.
       // Parse that unqualified-id.
       bool AllowConstructorName;
-      if (D.getDeclSpec().hasTypeSpecifier())
+      bool AllowDeductionGuide;
+      if (D.getDeclSpec().hasTypeSpecifier()) {
         AllowConstructorName = false;
-      else if (D.getCXXScopeSpec().isSet())
+        AllowDeductionGuide = false;
+      } else if (D.getCXXScopeSpec().isSet()) {
         AllowConstructorName =
           (D.getContext() == Declarator::FileContext ||
            D.getContext() == Declarator::MemberContext);
-      else
+        AllowDeductionGuide = false;
+      } else {
         AllowConstructorName = (D.getContext() == Declarator::MemberContext);
+        AllowDeductionGuide = 
+          (D.getContext() == Declarator::FileContext ||
+           D.getContext() == Declarator::MemberContext);
+      }
 
       SourceLocation TemplateKWLoc;
       bool HadScope = D.getCXXScopeSpec().isValid();
       if (ParseUnqualifiedId(D.getCXXScopeSpec(),
                              /*EnteringContext=*/true,
                              /*AllowDestructorName=*/true, AllowConstructorName,
-                             nullptr, TemplateKWLoc, D.getName()) ||
+                             AllowDeductionGuide, nullptr, TemplateKWLoc,
+                             D.getName()) ||
           // Once we're past the identifier, if the scope was bad, mark the
           // whole declarator bad.
           D.getCXXScopeSpec().isInvalid()) {
@@ -5361,11 +5555,28 @@ void Parser::ParseDirectDeclarator(Declarator &D) {
     D.SetRangeEnd(Tok.getLocation());
     ConsumeToken();
     goto PastIdentifier;
-  } else if (Tok.is(tok::identifier) && D.diagnoseIdentifier()) {
-    // A virt-specifier isn't treated as an identifier if it appears after a
-    // trailing-return-type.
-    if (D.getContext() != Declarator::TrailingReturnContext ||
-        !isCXX11VirtSpecifier(Tok)) {
+  } else if (Tok.is(tok::identifier) && !D.mayHaveIdentifier()) {
+    // We're not allowed an identifier here, but we got one. Try to figure out
+    // if the user was trying to attach a name to the type, or whether the name
+    // is some unrelated trailing syntax.
+    bool DiagnoseIdentifier = false;
+    if (D.hasGroupingParens())
+      // An identifier within parens is unlikely to be intended to be anything
+      // other than a name being "declared".
+      DiagnoseIdentifier = true;
+    else if (D.getContext() == Declarator::TemplateTypeArgContext)
+      // T<int N> is an accidental identifier; T<int N indicates a missing '>'.
+      DiagnoseIdentifier =
+          NextToken().isOneOf(tok::comma, tok::greater, tok::greatergreater);
+    else if (D.getContext() == Declarator::AliasDeclContext ||
+             D.getContext() == Declarator::AliasTemplateContext)
+      // The most likely error is that the ';' was forgotten.
+      DiagnoseIdentifier = NextToken().isOneOf(tok::comma, tok::semi);
+    else if (D.getContext() == Declarator::TrailingReturnContext &&
+             !isCXX11VirtSpecifier(Tok))
+      DiagnoseIdentifier = NextToken().isOneOf(
+          tok::comma, tok::semi, tok::equal, tok::l_brace, tok::kw_try);
+    if (DiagnoseIdentifier) {
       Diag(Tok.getLocation(), diag::err_unexpected_unqualified_id)
         << FixItHint::CreateRemoval(Tok.getLocation());
       D.SetIdentifier(nullptr, Tok.getLocation());
@@ -5409,6 +5620,21 @@ void Parser::ParseDirectDeclarator(Declarator &D) {
     if (Tok.is(tok::l_square))
       return ParseMisplacedBracketDeclarator(D);
     if (D.getContext() == Declarator::MemberContext) {
+      // Objective-C++: Detect C++ keywords and try to prevent further errors by
+      // treating these keyword as valid member names.
+      if (getLangOpts().ObjC1 && getLangOpts().CPlusPlus &&
+          Tok.getIdentifierInfo() &&
+          Tok.getIdentifierInfo()->isCPlusPlusKeyword(getLangOpts())) {
+        Diag(getMissingDeclaratorIdLoc(D, Tok.getLocation()),
+             diag::err_expected_member_name_or_semi_objcxx_keyword)
+            << Tok.getIdentifierInfo()
+            << (D.getDeclSpec().isEmpty() ? SourceRange()
+                                          : D.getDeclSpec().getSourceRange());
+        D.SetIdentifier(Tok.getIdentifierInfo(), Tok.getLocation());
+        D.SetRangeEnd(Tok.getLocation());
+        ConsumeToken();
+        goto PastIdentifier;
+      }
       Diag(getMissingDeclaratorIdLoc(D, Tok.getLocation()),
            diag::err_expected_member_name_or_semi)
           << (D.getDeclSpec().isEmpty() ? SourceRange()
@@ -5744,7 +5970,11 @@ void Parser::ParseFunctionDeclarator(Declarator &D,
 
       // Parse cv-qualifier-seq[opt].
       ParseTypeQualifierListOpt(DS, AR_NoAttributesParsed,
-                                /*AtomicAllowed*/ false);
+                                /*AtomicAllowed*/ false,
+                                /*IdentifierRequired=*/false,
+                                llvm::function_ref<void()>([&]() {
+                                  Actions.CodeCompleteFunctionQualifiers(DS, D);
+                                }));
       if (!DS.getSourceRange().getEnd().isInvalid()) {
         EndLoc = DS.getSourceRange().getEnd();
         ConstQualifierLoc = DS.getConstSpecLoc();
@@ -6097,9 +6327,10 @@ void Parser::ParseParameterDeclarationClause(
 
           // The argument isn't actually potentially evaluated unless it is
           // used.
-          EnterExpressionEvaluationContext Eval(Actions,
-                                              Sema::PotentiallyEvaluatedIfUsed,
-                                                Param);
+          EnterExpressionEvaluationContext Eval(
+              Actions,
+              Sema::ExpressionEvaluationContext::PotentiallyEvaluatedIfUsed,
+              Param);
 
           ExprResult DefArgResult;
           if (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace)) {
@@ -6249,8 +6480,8 @@ void Parser::ParseBracketDeclarator(Declarator &D) {
     if (getLangOpts().CPlusPlus) {
       NumElements = ParseConstantExpression();
     } else {
-      EnterExpressionEvaluationContext Unevaluated(Actions,
-                                                   Sema::ConstantEvaluated);
+      EnterExpressionEvaluationContext Unevaluated(
+          Actions, Sema::ExpressionEvaluationContext::ConstantEvaluated);
       NumElements =
           Actions.CorrectDelayedTyposInExpr(ParseAssignmentExpression());
     }
@@ -6385,8 +6616,9 @@ void Parser::ParseTypeofSpecifier(DeclSpec &DS) {
 
   const bool hasParens = Tok.is(tok::l_paren);
 
-  EnterExpressionEvaluationContext Unevaluated(Actions, Sema::Unevaluated,
-                                               Sema::ReuseLambdaContextDecl);
+  EnterExpressionEvaluationContext Unevaluated(
+      Actions, Sema::ExpressionEvaluationContext::Unevaluated,
+      Sema::ReuseLambdaContextDecl);
 
   bool isCastExpr;
   ParsedType CastTy;
@@ -6418,7 +6650,7 @@ void Parser::ParseTypeofSpecifier(DeclSpec &DS) {
     return;
   }
 
-  // If we get here, the operand to the typeof was an expresion.
+  // If we get here, the operand to the typeof was an expression.
   if (Operand.isInvalid()) {
     DS.SetTypeSpecError();
     return;