Vendor import of clang release_39 branch r276489:vendor/clang/clang-release_39-r276489

https://llvm.org/svn/llvm-project/cfe/branches/release_39@276489

1 files changed, 131 insertions, 62 deletions

diff --git a/lib/Parse/ParseTentative.cpp b/lib/Parse/ParseTentative.cpp
index 6fbcfd9bd217..7703c33b8780 100644
--- a/lib/Parse/ParseTentative.cpp
+++ b/lib/Parse/ParseTentative.cpp
@@ -125,10 +125,11 @@ bool Parser::isCXXSimpleDeclaration(bool AllowForRangeDecl) {
   // Ok, we have a simple-type-specifier/typename-specifier followed by a '(',
   // or an identifier which doesn't resolve as anything. We need tentative
   // parsing...
-
-  TentativeParsingAction PA(*this);
-  TPR = TryParseSimpleDeclaration(AllowForRangeDecl);
-  PA.Revert();
+ 
+  {
+    RevertingTentativeParsingAction PA(*this);
+    TPR = TryParseSimpleDeclaration(AllowForRangeDecl);
+  }
 
   // In case of an error, let the declaration parsing code handle it.
   if (TPR == TPResult::Error)
@@ -329,10 +330,70 @@ Parser::TPResult Parser::TryParseInitDeclaratorList() {
   return TPResult::Ambiguous;
 }
 
-/// isCXXConditionDeclaration - Disambiguates between a declaration or an
-/// expression for a condition of a if/switch/while/for statement.
-/// If during the disambiguation process a parsing error is encountered,
-/// the function returns true to let the declaration parsing code handle it.
+struct Parser::ConditionDeclarationOrInitStatementState {
+  Parser &P;
+  bool CanBeExpression = true;
+  bool CanBeCondition = true;
+  bool CanBeInitStatement;
+
+  ConditionDeclarationOrInitStatementState(Parser &P, bool CanBeInitStatement)
+      : P(P), CanBeInitStatement(CanBeInitStatement) {}
+
+  void markNotExpression() {
+    CanBeExpression = false;
+
+    if (CanBeCondition && CanBeInitStatement) {
+      // FIXME: Unify the parsing codepaths for condition variables and
+      // simple-declarations so that we don't need to eagerly figure out which
+      // kind we have here. (Just parse init-declarators until we reach a
+      // semicolon or right paren.)
+      RevertingTentativeParsingAction PA(P);
+      P.SkipUntil(tok::r_paren, tok::semi, StopBeforeMatch);
+      if (P.Tok.isNot(tok::r_paren))
+        CanBeCondition = false;
+      if (P.Tok.isNot(tok::semi))
+        CanBeInitStatement = false;
+    }
+  }
+
+  bool markNotCondition() {
+    CanBeCondition = false;
+    return !CanBeInitStatement || !CanBeExpression;
+  }
+
+  bool update(TPResult IsDecl) {
+    switch (IsDecl) {
+    case TPResult::True:
+      markNotExpression();
+      return true;
+    case TPResult::False:
+      CanBeCondition = CanBeInitStatement = false;
+      return true;
+    case TPResult::Ambiguous:
+      return false;
+    case TPResult::Error:
+      CanBeExpression = CanBeCondition = CanBeInitStatement = false;
+      return true;
+    }
+    llvm_unreachable("unknown tentative parse result");
+  }
+
+  ConditionOrInitStatement result() const {
+    assert(CanBeExpression + CanBeCondition + CanBeInitStatement < 2 &&
+           "result called but not yet resolved");
+    if (CanBeExpression)
+      return ConditionOrInitStatement::Expression;
+    if (CanBeCondition)
+      return ConditionOrInitStatement::ConditionDecl;
+    if (CanBeInitStatement)
+      return ConditionOrInitStatement::InitStmtDecl;
+    return ConditionOrInitStatement::Error;
+  }
+};
+
+/// \brief Disambiguates between a declaration in a condition, a
+/// simple-declaration in an init-statement, and an expression for
+/// a condition of a if/switch statement.
 ///
 ///       condition:
 ///         expression
@@ -341,47 +402,64 @@ Parser::TPResult Parser::TryParseInitDeclaratorList() {
 /// [C++11] type-specifier-seq declarator braced-init-list
 /// [GNU]   type-specifier-seq declarator simple-asm-expr[opt] attributes[opt]
 ///             '=' assignment-expression
+///       simple-declaration:
+///         decl-specifier-seq init-declarator-list[opt] ';'
 ///
-bool Parser::isCXXConditionDeclaration() {
-  TPResult TPR = isCXXDeclarationSpecifier();
-  if (TPR != TPResult::Ambiguous)
-    return TPR != TPResult::False; // Returns true for TPResult::True or
-                                   // TPResult::Error.
-
-  // FIXME: Add statistics about the number of ambiguous statements encountered
-  // and how they were resolved (number of declarations+number of expressions).
+/// Note that, unlike isCXXSimpleDeclaration, we must disambiguate all the way
+/// to the ';' to disambiguate cases like 'int(x))' (an expression) from
+/// 'int(x);' (a simple-declaration in an init-statement).
+Parser::ConditionOrInitStatement
+Parser::isCXXConditionDeclarationOrInitStatement(bool CanBeInitStatement) {
+  ConditionDeclarationOrInitStatementState State(*this, CanBeInitStatement);
 
-  // Ok, we have a simple-type-specifier/typename-specifier followed by a '('.
-  // We need tentative parsing...
+  if (State.update(isCXXDeclarationSpecifier()))
+    return State.result();
 
-  TentativeParsingAction PA(*this);
+  // It might be a declaration; we need tentative parsing.
+  RevertingTentativeParsingAction PA(*this);
 
-  // type-specifier-seq
-  TryConsumeDeclarationSpecifier();
+  // FIXME: A tag definition unambiguously tells us this is an init-statement.
+  if (State.update(TryConsumeDeclarationSpecifier()))
+    return State.result();
   assert(Tok.is(tok::l_paren) && "Expected '('");
 
-  // declarator
-  TPR = TryParseDeclarator(false/*mayBeAbstract*/);
+  while (true) {
+    // Consume a declarator.
+    if (State.update(TryParseDeclarator(false/*mayBeAbstract*/)))
+      return State.result();
+
+    // Attributes, asm label, or an initializer imply this is not an expression.
+    // FIXME: Disambiguate properly after an = instead of assuming that it's a
+    // valid declaration.
+    if (Tok.isOneOf(tok::equal, tok::kw_asm, tok::kw___attribute) ||
+        (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace))) {
+      State.markNotExpression();
+      return State.result();
+    }
 
-  // In case of an error, let the declaration parsing code handle it.
-  if (TPR == TPResult::Error)
-    TPR = TPResult::True;
+    // At this point, it can't be a condition any more, because a condition
+    // must have a brace-or-equal-initializer.
+    if (State.markNotCondition())
+      return State.result();
 
-  if (TPR == TPResult::Ambiguous) {
-    // '='
-    // [GNU] simple-asm-expr[opt] attributes[opt]
-    if (Tok.isOneOf(tok::equal, tok::kw_asm, tok::kw___attribute))
-      TPR = TPResult::True;
-    else if (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace))
-      TPR = TPResult::True;
-    else
-      TPR = TPResult::False;
-  }
+    // A parenthesized initializer could be part of an expression or a
+    // simple-declaration.
+    if (Tok.is(tok::l_paren)) {
+      ConsumeParen();
+      SkipUntil(tok::r_paren, StopAtSemi);
+    }
 
-  PA.Revert();
+    if (!TryConsumeToken(tok::comma))
+      break;
+  }
 
-  assert(TPR == TPResult::True || TPR == TPResult::False);
-  return TPR == TPResult::True;
+  // We reached the end. If it can now be some kind of decl, then it is.
+  if (State.CanBeCondition && Tok.is(tok::r_paren))
+    return ConditionOrInitStatement::ConditionDecl;
+  else if (State.CanBeInitStatement && Tok.is(tok::semi))
+    return ConditionOrInitStatement::InitStmtDecl;
+  else
+    return ConditionOrInitStatement::Expression;
 }
 
   /// \brief Determine whether the next set of tokens contains a type-id.
@@ -423,7 +501,7 @@ bool Parser::isCXXTypeId(TentativeCXXTypeIdContext Context, bool &isAmbiguous) {
   // Ok, we have a simple-type-specifier/typename-specifier followed by a '('.
   // We need tentative parsing...
 
-  TentativeParsingAction PA(*this);
+  RevertingTentativeParsingAction PA(*this);
 
   // type-specifier-seq
   TryConsumeDeclarationSpecifier();
@@ -456,8 +534,6 @@ bool Parser::isCXXTypeId(TentativeCXXTypeIdContext Context, bool &isAmbiguous) {
       TPR = TPResult::False;
   }
 
-  PA.Revert();
-
   assert(TPR == TPResult::True || TPR == TPResult::False);
   return TPR == TPResult::True;
 }
@@ -508,7 +584,7 @@ Parser::isCXX11AttributeSpecifier(bool Disambiguate,
   if (!Disambiguate && !getLangOpts().ObjC1)
     return CAK_AttributeSpecifier;
 
-  TentativeParsingAction PA(*this);
+  RevertingTentativeParsingAction PA(*this);
 
   // Opening brackets were checked for above.
   ConsumeBracket();
@@ -520,8 +596,6 @@ Parser::isCXX11AttributeSpecifier(bool Disambiguate,
     bool IsAttribute = SkipUntil(tok::r_square);
     IsAttribute &= Tok.is(tok::r_square);
 
-    PA.Revert();
-
     return IsAttribute ? CAK_AttributeSpecifier : CAK_InvalidAttributeSpecifier;
   }
 
@@ -542,8 +616,6 @@ Parser::isCXX11AttributeSpecifier(bool Disambiguate,
     // A lambda cannot end with ']]', and an attribute must.
     bool IsAttribute = Tok.is(tok::r_square);
 
-    PA.Revert();
-
     if (IsAttribute)
       // Case 1: C++11 attribute.
       return CAK_AttributeSpecifier;
@@ -564,7 +636,6 @@ Parser::isCXX11AttributeSpecifier(bool Disambiguate,
   while (Tok.isNot(tok::r_square)) {
     if (Tok.is(tok::comma)) {
       // Case 1: Stray commas can only occur in attributes.
-      PA.Revert();
       return CAK_AttributeSpecifier;
     }
 
@@ -611,8 +682,6 @@ Parser::isCXX11AttributeSpecifier(bool Disambiguate,
     }
   }
 
-  PA.Revert();
-
   if (IsAttribute)
     // Case 1: C++11 statement attribute.
     return CAK_AttributeSpecifier;
@@ -833,7 +902,7 @@ Parser::TPResult Parser::TryParseDeclarator(bool mayBeAbstract,
       // '(' abstract-declarator ')'
       if (Tok.isOneOf(tok::kw___attribute, tok::kw___declspec, tok::kw___cdecl,
                       tok::kw___stdcall, tok::kw___fastcall, tok::kw___thiscall,
-                      tok::kw___vectorcall, tok::kw___unaligned))
+                      tok::kw___vectorcall))
         return TPResult::True; // attributes indicate declaration
       TPResult TPR = TryParseDeclarator(mayBeAbstract, mayHaveIdentifier);
       if (TPR != TPResult::Ambiguous)
@@ -946,6 +1015,7 @@ Parser::isExpressionOrTypeSpecifierSimple(tok::TokenKind Kind) {
   case tok::kw_char:
   case tok::kw_const:
   case tok::kw_double:
+  case tok::kw___float128:
   case tok::kw_enum:
   case tok::kw_half:
   case tok::kw_float:
@@ -987,6 +1057,8 @@ Parser::isExpressionOrTypeSpecifierSimple(tok::TokenKind Kind) {
   case tok::kw___pixel:
   case tok::kw___bool:
   case tok::kw__Atomic:
+#define GENERIC_IMAGE_TYPE(ImgType, Id) case tok::kw_##ImgType##_t:
+#include "clang/Basic/OpenCLImageTypes.def"
   case tok::kw___unknown_anytype:
     return TPResult::False;
 
@@ -1317,7 +1389,7 @@ Parser::isCXXDeclarationSpecifier(Parser::TPResult BracedCastResult,
                                                      Tok.getAnnotationRange(),
                                                      SS);
         if (SS.getScopeRep() && SS.getScopeRep()->isDependent()) {
-          TentativeParsingAction PA(*this);
+          RevertingTentativeParsingAction PA(*this);
           ConsumeToken();
           ConsumeToken();
           bool isIdentifier = Tok.is(tok::identifier);
@@ -1325,7 +1397,6 @@ Parser::isCXXDeclarationSpecifier(Parser::TPResult BracedCastResult,
           if (!isIdentifier)
             TPR = isCXXDeclarationSpecifier(BracedCastResult,
                                             HasMissingTypename);
-          PA.Revert();
 
           if (isIdentifier ||
               TPR == TPResult::True || TPR == TPResult::Error)
@@ -1337,6 +1408,8 @@ Parser::isCXXDeclarationSpecifier(Parser::TPResult BracedCastResult,
             *HasMissingTypename = true;
             return TPResult::Ambiguous;
           }
+
+          // FIXME: Fails to either revert or commit the tentative parse!
         } else {
           // Try to resolve the name. If it doesn't exist, assume it was
           // intended to name a type and keep disambiguating.
@@ -1388,15 +1461,13 @@ Parser::isCXXDeclarationSpecifier(Parser::TPResult BracedCastResult,
     // In Objective-C, we might have a protocol-qualified type.
     if (getLangOpts().ObjC1 && NextToken().is(tok::less)) {
       // Tentatively parse the protocol qualifiers.
-      TentativeParsingAction PA(*this);
+      RevertingTentativeParsingAction PA(*this);
       ConsumeToken(); // The type token
       
       TPResult TPR = TryParseProtocolQualifiers();
       bool isFollowedByParen = Tok.is(tok::l_paren);
       bool isFollowedByBrace = Tok.is(tok::l_brace);
       
-      PA.Revert();
-      
       if (TPR == TPResult::Error)
         return TPResult::Error;
       
@@ -1424,6 +1495,7 @@ Parser::isCXXDeclarationSpecifier(Parser::TPResult BracedCastResult,
   case tok::kw_half:
   case tok::kw_float:
   case tok::kw_double:
+  case tok::kw___float128:
   case tok::kw_void:
   case tok::annot_decltype:
     if (NextToken().is(tok::l_paren))
@@ -1448,14 +1520,12 @@ Parser::isCXXDeclarationSpecifier(Parser::TPResult BracedCastResult,
     if (NextToken().isNot(tok::l_paren))
       return TPResult::True;
 
-    TentativeParsingAction PA(*this);
+    RevertingTentativeParsingAction PA(*this);
 
     TPResult TPR = TryParseTypeofSpecifier();
     bool isFollowedByParen = Tok.is(tok::l_paren);
     bool isFollowedByBrace = Tok.is(tok::l_brace);
 
-    PA.Revert();
-
     if (TPR == TPResult::Error)
       return TPResult::Error;
 
@@ -1515,6 +1585,7 @@ bool Parser::isCXXDeclarationSpecifierAType() {
   case tok::kw_half:
   case tok::kw_float:
   case tok::kw_double:
+  case tok::kw___float128:
   case tok::kw_void:
   case tok::kw___unknown_anytype:
   case tok::kw___auto_type:
@@ -1594,7 +1665,7 @@ bool Parser::isCXXFunctionDeclarator(bool *IsAmbiguous) {
   // ambiguities mentioned in 6.8, the resolution is to consider any construct
   // that could possibly be a declaration a declaration.
 
-  TentativeParsingAction PA(*this);
+  RevertingTentativeParsingAction PA(*this);
 
   ConsumeParen();
   bool InvalidAsDeclaration = false;
@@ -1618,8 +1689,6 @@ bool Parser::isCXXFunctionDeclarator(bool *IsAmbiguous) {
     }
   }
 
-  PA.Revert();
-
   if (IsAmbiguous && TPR == TPResult::Ambiguous)
     *IsAmbiguous = true;