Simplify Condition Resolution

include/swift/AST/AST.h

@@ -27,7 +27,6 @@
 #include "swift/AST/ParameterList.h"
 #include "swift/AST/Pattern.h"
 #include "swift/AST/Stmt.h"
-#include "swift/AST/StmtTransformer.h"
 #include "swift/AST/Types.h"
 #include "swift/AST/TypeRepr.h"
 

include/swift/AST/Decl.h

@@ -587,12 +587,8 @@ class alignas(1 << DeclAlignInBits) Decl {
 
     /// Whether this decl is missing its closing '#endif'.
     unsigned HadMissingEnd : 1;
-
-    /// Whether this condition has been resolved either statically by Parse or
-    /// later by Condition Resolution.
-    unsigned HasBeenResolved : 1;
   };
-  enum { NumIfConfigDeclBits = NumDeclBits + 2 };
+  enum { NumIfConfigDeclBits = NumDeclBits + 1 };
   static_assert(NumIfConfigDeclBits <= 32, "fits in an unsigned");
 
 protected:
@@ -1935,8 +1931,7 @@ struct IfConfigDeclClause {
 
   IfConfigDeclClause(SourceLoc Loc, Expr *Cond, ArrayRef<Decl*> Members,
                      bool isActive)
-    : Loc(Loc), Cond(Cond), Members(Members), isActive(isActive) {
-  }
+    : Loc(Loc), Cond(Cond), Members(Members), isActive(isActive) {}
 };
 
 
@@ -1949,15 +1944,13 @@ class IfConfigDecl : public Decl {
   /// The array is ASTContext allocated.
   ArrayRef<IfConfigDeclClause> Clauses;
   SourceLoc EndLoc;
-
 public:
 
   IfConfigDecl(DeclContext *Parent, ArrayRef<IfConfigDeclClause> Clauses,
                SourceLoc EndLoc, bool HadMissingEnd)
     : Decl(DeclKind::IfConfig, Parent), Clauses(Clauses), EndLoc(EndLoc)
   {
     IfConfigDeclBits.HadMissingEnd = HadMissingEnd;
-    IfConfigDeclBits.HasBeenResolved = false;
   }
 
   ArrayRef<IfConfigDeclClause> getClauses() const { return Clauses; }
@@ -1974,9 +1967,6 @@ class IfConfigDecl : public Decl {
       return Clause->Members;
     return {};
   }
-
-  bool isResolved() const { return IfConfigDeclBits.HasBeenResolved; }
-  void setResolved() { IfConfigDeclBits.HasBeenResolved = true; }
 
   SourceLoc getEndLoc() const { return EndLoc; }
   SourceLoc getLoc() const { return Clauses[0].Loc; }

include/swift/AST/DiagnosticsParse.def

@@ -1339,7 +1339,7 @@ ERROR(unsupported_conditional_compilation_unary_expression,none,
       "expected unary '!' expression", ())
 ERROR(unsupported_platform_condition_expression,none,
       "unexpected platform condition "
-      "(expected 'canImport', 'os', 'arch', or 'swift')",
+      "(expected 'os', 'arch', or 'swift')",
       ())
 ERROR(platform_condition_expected_one_argument,none,
       "expected only one argument to platform condition",

include/swift/AST/Stmt.h

@@ -685,7 +685,6 @@ class IfConfigStmt : public Stmt {
   ArrayRef<IfConfigStmtClause> Clauses;
   SourceLoc EndLoc;
   bool HadMissingEnd;
-  bool HasBeenResolved = false;
 
 public:
   IfConfigStmt(ArrayRef<IfConfigStmtClause> Clauses, SourceLoc EndLoc,
@@ -699,9 +698,6 @@ class IfConfigStmt : public Stmt {
   SourceLoc getEndLoc() const { return EndLoc; }
 
   bool hadMissingEnd() const { return HadMissingEnd; }
-
-  bool isResolved() { return HasBeenResolved; }
-  void setResolved() { HasBeenResolved = true; }
 
   const ArrayRef<IfConfigStmtClause> &getClauses() const { return Clauses; }
 

include/swift/Parse/Parser.h

@@ -59,11 +59,10 @@ namespace swift {
     TopLevelCode,
     /// The top-level of a file, when in parse-as-library mode.
     TopLevelLibrary,
-    /// The body of the clause of an #if/#else/#endif block
-    ConditionalBlock,
-    /// The body of the clause of an #if/#else/#endif block that was statically
-    /// determined to be inactive.
-    StaticallyInactiveConditionalBlock,
+    /// The body of the inactive clause of an #if/#else/#endif block
+    InactiveConditionalBlock,
+    /// The body of the active clause of an #if/#else/#endif block
+    ActiveConditionalBlock,
   };
 
 
@@ -620,10 +619,6 @@ class Parser {
                                    BraceItemListKind::Brace);
   ParserResult<BraceStmt> parseBraceItemList(Diag<> ID);
 
-  void parseIfConfigClauseElements(bool isInactive,
-                                   BraceItemListKind Kind,
-                                   SmallVectorImpl<ASTNode> &Elements);
-
   void parseTopLevelCodeDeclDelayed();
 
   //===--------------------------------------------------------------------===//
@@ -1231,13 +1226,13 @@ class Parser {
   ParserResult<CaseStmt> parseStmtCase();
 
   /// Classify the condition of an #if directive according to whether it can
-  /// be evaluated statically.  If evaluation is not possible, the result is
-  /// 'None'.
-  static Optional<bool>
+  /// be evaluated statically.  The first member of the pair indicates whether
+  /// parsing of the condition body should occur, the second contains the result
+  /// of evaluating the conditional expression.
+  static ConditionalCompilationExprState
   classifyConditionalCompilationExpr(Expr *condition,
                                      ASTContext &context,
-                                     DiagnosticEngine &diags,
-                                     bool fullCheck = false);
+                                     DiagnosticEngine &diags);
 
   //===--------------------------------------------------------------------===//
   // Generics Parsing

include/swift/Parse/ParserResult.h

@@ -217,6 +217,75 @@ template <typename T> ParserResult<T>::ParserResult(ParserStatus Status) {
     setHasCodeCompletion();
 }
 
+enum class ConditionalCompilationExprKind {
+  Unknown,
+  Error,
+  OS,
+  Arch,
+  LanguageVersion,
+  CompilerVersion,
+  Binary,
+  Paren,
+  DeclRef,
+  Boolean,
+  Integer,
+  Import,
+};
+
+class ConditionalCompilationExprState {
+
+  uint8_t ConditionActive : 1;
+  uint8_t Kind : 7;
+public:
+  ConditionalCompilationExprState() : ConditionActive(false) {
+    setKind(ConditionalCompilationExprKind::Unknown);
+  }
+
+  ConditionalCompilationExprState(bool ConditionActive,
+                                  ConditionalCompilationExprKind Kind)
+  : ConditionActive(ConditionActive) {
+    setKind(Kind);
+  }
+
+  bool isConditionActive() const {
+    return ConditionActive;
+  }
+
+  void setConditionActive(bool A) {
+    ConditionActive = A;
+  }
+
+  ConditionalCompilationExprKind getKind() const {
+    return static_cast<ConditionalCompilationExprKind>(Kind);
+  }
+
+  void setKind(ConditionalCompilationExprKind K) {
+    Kind = static_cast<uint8_t>(K);
+    assert(getKind() == K);
+  }
+
+  bool shouldParse() const {
+    if (getKind() == ConditionalCompilationExprKind::Error)
+      return true;
+    return ConditionActive ||
+    (getKind() != ConditionalCompilationExprKind::CompilerVersion &&
+     getKind() != ConditionalCompilationExprKind::LanguageVersion);
+  }
+
+  static ConditionalCompilationExprState error() {
+    return {false, ConditionalCompilationExprKind::Error};
+  }
+};
+
+ConditionalCompilationExprState
+operator&&(const ConditionalCompilationExprState lhs,
+           const ConditionalCompilationExprState rhs);
+ConditionalCompilationExprState
+operator||(const ConditionalCompilationExprState lhs,
+           const ConditionalCompilationExprState rhs);
+ConditionalCompilationExprState
+operator!(const ConditionalCompilationExprState Result);
+
 } // namespace swift
 
 #endif // LLVM_SWIFT_PARSER_PARSER_RESULT_H

include/swift/Parse/Scope.h

@@ -54,7 +54,7 @@ class ScopeInfo {
   /// scope.
   void addToScope(ValueDecl *D, Parser &TheParser);
 
-  bool isStaticallyInactiveConfigBlock() const;
+  bool isInactiveConfigBlock() const;
 
   SavedScope saveCurrentScope();
 };
@@ -91,7 +91,7 @@ class SavedScope {
   ScopeInfo::ScopedHTDetachedScopeTy HTDetachedScope;
   unsigned Depth;
   ScopeKind Kind;
-  bool IsStaticallyInactiveConfigBlock;
+  bool IsInactiveConfigBlock;
 
   SavedScope() = delete;
   SavedScope(const SavedScope &) = delete;
@@ -103,9 +103,9 @@ class SavedScope {
   ~SavedScope() = default;
 
   SavedScope(ScopeInfo::ScopedHTDetachedScopeTy &&HTDetachedScope,
-             unsigned Depth, ScopeKind Kind, bool IsStaticallyInactiveConfigBlock)
+             unsigned Depth, ScopeKind Kind, bool isInactiveConfigBlock)
     : HTDetachedScope(std::move(HTDetachedScope)), Depth(Depth), Kind(Kind),
-      IsStaticallyInactiveConfigBlock(IsStaticallyInactiveConfigBlock) {}
+      IsInactiveConfigBlock(isInactiveConfigBlock) {}
 };
 
 /// Scope - This class represents lexical scopes.  These objects are created
@@ -125,13 +125,12 @@ class Scope {
   unsigned PrevResolvableDepth;
   unsigned Depth;
   ScopeKind Kind;
-  bool IsStaticallyInactiveConfigBlock;
+  bool IsInactiveConfigBlock;
 
   /// \brief Save this scope so that it can be re-entered later.  Transfers the
   /// ownership of the scope frame to returned object.
   SavedScope saveScope() {
-    return SavedScope(HTScope.detach(), Depth, Kind,
-                      IsStaticallyInactiveConfigBlock);
+    return SavedScope(HTScope.detach(), Depth, Kind, IsInactiveConfigBlock);
   }
 
   unsigned getDepth() const {
@@ -142,7 +141,7 @@ class Scope {
 
 public:
   /// \brief Create a lexical scope of the specified kind.
-  Scope(Parser *P, ScopeKind SC, bool IsStaticallyInactiveConfigBlock = false);
+  Scope(Parser *P, ScopeKind SC, bool isInactiveConfigBlock = false);
 
   /// \brief Re-enter the specified scope, transferring the ownership of the
   /// scope frame to the new object.
@@ -175,15 +174,10 @@ inline ValueDecl *ScopeInfo::lookupValueName(DeclName Name) {
   return Res.second;
 }
 
-inline bool ScopeInfo::isStaticallyInactiveConfigBlock() const {
-  auto scope = CurScope;
-  while (scope) {
-    if (scope->IsStaticallyInactiveConfigBlock) {
-      return true;
-    }
-    scope = scope->PrevScope;
-  }
-  return false;
+inline bool ScopeInfo::isInactiveConfigBlock() const {
+  if (!CurScope)
+    return false;
+  return CurScope->IsInactiveConfigBlock;
 }
 
 inline SavedScope ScopeInfo::saveCurrentScope() {

include/swift/Subsystems.h

@@ -130,15 +130,6 @@ namespace swift {
                               bool TokenizeInterpolatedString = true,
                               ArrayRef<Token> SplitTokens = ArrayRef<Token>());
 
-  /// Once parsing is complete, this walks the AST to resolve condition clauses
-  /// and other top-level validation.
-  void performConditionResolution(SourceFile &SF);
-
-  /// \brief Finish condition resolution for the bodies of function nodes that
-  /// were delayed during the first parsing pass.
-  void performDelayedConditionResolution(Decl *D, SourceFile &BSF,
-                                         SmallVectorImpl<Decl *> &ExtraTLCDs);
-
   /// Once parsing is complete, this walks the AST to resolve imports, record
   /// operators, and do other top-level validation.
   ///

lib/AST/CMakeLists.txt

@@ -39,7 +39,6 @@ add_swift_library(swiftAST STATIC
   RawComment.cpp
   SILLayout.cpp
   Stmt.cpp
-  StmtTransformer.cpp
   SourceEntityWalker.cpp
   Substitution.cpp
   SubstitutionMap.cpp