add __rvalue(expression) builtin

compiler/src/dmd/astbase.d

@@ -4548,6 +4548,7 @@ struct ASTBase
         EXP op;
         ubyte size;
         ubyte parens;
+        ubyte rvalue;              // consider this an rvalue, even if it is an lvalue
         Type type;
         Loc loc;
 

compiler/src/dmd/clone.d

@@ -1617,6 +1617,7 @@ private Statement generateCopyCtorBody(StructDeclaration sd)
  */
 bool needCopyCtor(StructDeclaration sd, out bool hasCpCtor)
 {
+    //printf("needCopyCtor() %s\n", sd.toChars());
     if (global.errors)
         return false;
 
@@ -1655,7 +1656,7 @@ bool needCopyCtor(StructDeclaration sd, out bool hasCpCtor)
 
     if (cpCtor)
     {
-        if (rvalueCtor)
+        if (0 && rvalueCtor)
         {
             .error(sd.loc, "`struct %s` may not define both a rvalue constructor and a copy constructor", sd.toChars());
             errorSupplemental(rvalueCtor.loc,"rvalue constructor defined here");

compiler/src/dmd/dscope.d

@@ -24,6 +24,7 @@ import dmd.dclass;
 import dmd.declaration;
 import dmd.dmodule;
 import dmd.doc;
+import dmd.dstruct;
 import dmd.dsymbol;
 import dmd.dsymbolsem;
 import dmd.dtemplate;
@@ -156,6 +157,7 @@ extern (C++) struct Scope
 
     AliasDeclaration aliasAsg; /// if set, then aliasAsg is being assigned a new value,
                                /// do not set wasRead for it
+    StructDeclaration argStruct;    /// elimiate recursion when looking for rvalue construction
 
     extern (D) __gshared Scope* freelist;
 

compiler/src/dmd/e2ir.d

@@ -5532,6 +5532,8 @@ elem *callfunc(const ref Loc loc,
                     v = ve.var.isVarDeclaration();
                 bool copy = !(v && (v.isArgDtorVar || v.storage_class & STC.rvalue)); // copy unless the destructor is going to be run on it
                                                     // then assume the frontend took care of the copying and pass it by ref
+                if (arg.rvalue)                     // marked with __rvalue
+                    copy = false;
 
                 elems[i] = addressElem(ea, arg.type, copy);
                 continue;

compiler/src/dmd/expression.d

@@ -297,6 +297,7 @@ extern (C++) abstract class Expression : ASTNode
     Loc loc;        // file location
     const EXP op;   // to minimize use of dynamic_cast
     bool parens;    // if this is a parenthesized expression
+    bool rvalue;    // true if this is considered to be an rvalue, even if it is an lvalue
 
     extern (D) this(const ref Loc loc, EXP op) scope @safe
     {
@@ -1307,7 +1308,7 @@ extern (C++) class IdentifierExp : Expression
 
     override final bool isLvalue()
     {
-        return true;
+        return !this.rvalue;
     }
 
     override void accept(Visitor v)
@@ -1351,7 +1352,7 @@ extern (C++) final class DsymbolExp : Expression
 
     override bool isLvalue()
     {
-        return true;
+        return !rvalue;
     }
 
     override void accept(Visitor v)
@@ -1397,7 +1398,7 @@ extern (C++) class ThisExp : Expression
     override final bool isLvalue()
     {
         // Class `this` should be an rvalue; struct `this` should be an lvalue.
-        return type.toBasetype().ty != Tclass;
+        return !rvalue && type.toBasetype().ty != Tclass;
     }
 
     override void accept(Visitor v)
@@ -1782,7 +1783,7 @@ extern (C++) final class StringExp : Expression
         /* string literal is rvalue in default, but
          * conversion to reference of static array is only allowed.
          */
-        return (type && type.toBasetype().ty == Tsarray);
+        return !rvalue && (type && type.toBasetype().ty == Tsarray);
     }
 
     /********************************
@@ -2719,7 +2720,7 @@ extern (C++) final class VarExp : SymbolExp
 
     override bool isLvalue()
     {
-        if (var.storage_class & (STC.lazy_ | STC.rvalue | STC.manifest))
+        if (rvalue || var.storage_class & (STC.lazy_ | STC.rvalue | STC.manifest))
             return false;
         return true;
     }
@@ -3098,7 +3099,7 @@ extern (C++) class BinAssignExp : BinExp
 
     override final bool isLvalue()
     {
-        return true;
+        return !rvalue;
     }
 
     override void accept(Visitor v)
@@ -3303,6 +3304,8 @@ extern (C++) final class DotVarExp : UnaExp
 
     override bool isLvalue()
     {
+        if (rvalue)
+            return false;
         if (e1.op != EXP.structLiteral)
             return true;
         auto vd = var.isVarDeclaration();
@@ -3530,6 +3533,8 @@ extern (C++) final class CallExp : UnaExp
 
     override bool isLvalue()
     {
+        if (rvalue)
+            return false;
         Type tb = e1.type.toBasetype();
         if (tb.ty == Tdelegate || tb.ty == Tpointer)
             tb = tb.nextOf();
@@ -3648,7 +3653,7 @@ extern (C++) final class PtrExp : UnaExp
 
     override bool isLvalue()
     {
-        return true;
+        return !rvalue;
     }
 
     override void accept(Visitor v)
@@ -3777,7 +3782,7 @@ extern (C++) final class CastExp : UnaExp
     override bool isLvalue()
     {
         //printf("e1.type = %s, to.type = %s\n", e1.type.toChars(), to.toChars());
-        if (!e1.isLvalue())
+        if (rvalue || !e1.isLvalue())
             return false;
         return (to.ty == Tsarray && (e1.type.ty == Tvector || e1.type.ty == Tsarray)) ||
             e1.type.mutableOf.unSharedOf().equals(to.mutableOf().unSharedOf());
@@ -3834,7 +3839,7 @@ extern (C++) final class VectorArrayExp : UnaExp
 
     override bool isLvalue()
     {
-        return e1.isLvalue();
+        return !rvalue && e1.isLvalue();
     }
 
     override void accept(Visitor v)
@@ -3891,7 +3896,7 @@ extern (C++) final class SliceExp : UnaExp
         /* slice expression is rvalue in default, but
          * conversion to reference of static array is only allowed.
          */
-        return (type && type.toBasetype().ty == Tsarray);
+        return !rvalue && (type && type.toBasetype().ty == Tsarray);
     }
 
     override Optional!bool toBool()
@@ -3956,6 +3961,8 @@ extern (C++) final class ArrayExp : UnaExp
 
     override bool isLvalue()
     {
+        if (rvalue)
+            return false;
         if (type && type.toBasetype().ty == Tvoid)
             return false;
         return true;
@@ -4005,7 +4012,7 @@ extern (C++) final class CommaExp : BinExp
 
     override bool isLvalue()
     {
-        return e2.isLvalue();
+        return !rvalue && e2.isLvalue();
     }
 
     override Optional!bool toBool()
@@ -4080,7 +4087,7 @@ extern (C++) final class DelegatePtrExp : UnaExp
 
     override bool isLvalue()
     {
-        return e1.isLvalue();
+        return !rvalue && e1.isLvalue();
     }
 
     override void accept(Visitor v)
@@ -4103,7 +4110,7 @@ extern (C++) final class DelegateFuncptrExp : UnaExp
 
     override bool isLvalue()
     {
-        return e1.isLvalue();
+        return !rvalue && e1.isLvalue();
     }
 
     override void accept(Visitor v)
@@ -4143,6 +4150,8 @@ extern (C++) final class IndexExp : BinExp
 
     override bool isLvalue()
     {
+        if (rvalue)
+            return false;
         auto t1b = e1.type.toBasetype();
         if (t1b.isTypeAArray() || t1b.isTypeSArray() ||
             (e1.isIndexExp() && t1b != t1b.isTypeDArray()))
@@ -4251,7 +4260,7 @@ extern (C++) class AssignExp : BinExp
         {
             return false;
         }
-        return true;
+        return !rvalue;
     }
 
     override void accept(Visitor v)
@@ -4982,7 +4991,7 @@ extern (C++) final class CondExp : BinExp
 
     override bool isLvalue()
     {
-        return e1.isLvalue() && e2.isLvalue();
+        return !rvalue && e1.isLvalue() && e2.isLvalue();
     }
 
     override void accept(Visitor v)

compiler/src/dmd/expression.h

@@ -78,6 +78,7 @@ class Expression : public ASTNode
     Loc loc;                    // file location
     EXP op;                     // to minimize use of dynamic_cast
     d_bool parens;              // if this is a parenthesized expression
+    d_bool rvalue;              // consider this an rvalue, even if it is an lvalue
 
     size_t size() const;
     static void _init();

compiler/src/dmd/expressionsem.d

@@ -3892,6 +3892,8 @@ private extern (C++) final class ExpressionSemanticVisitor : Visitor
             return;
         }
 
+        scope (success) result.rvalue = exp.rvalue;
+
         Dsymbol scopesym;
         Dsymbol s = sc.search(exp.loc, exp.ident, scopesym);
         if (s)

compiler/src/dmd/frontend.h

@@ -2068,6 +2068,7 @@ enum class EXP : uint8_t
     _Generic_ = 125u,
     interval = 126u,
     loweredAssignExp = 127u,
+    rvalue = 128u,
 };
 
 typedef uint64_t dinteger_t;
@@ -2105,6 +2106,7 @@ class Expression : public ASTNode
     Loc loc;
     const EXP op;
     bool parens;
+    bool rvalue;
     size_t size() const;
     static void _init();
     static void deinitialize();
@@ -2888,33 +2890,34 @@ enum class TOK : uint8_t
     wchar_tLiteral = 196u,
     endOfLine = 197u,
     whitespace = 198u,
-    inline_ = 199u,
-    register_ = 200u,
-    restrict_ = 201u,
-    signed_ = 202u,
-    sizeof_ = 203u,
-    typedef_ = 204u,
-    unsigned_ = 205u,
-    volatile_ = 206u,
-    _Alignas_ = 207u,
-    _Alignof_ = 208u,
-    _Atomic_ = 209u,
-    _Bool_ = 210u,
-    _Complex_ = 211u,
-    _Generic_ = 212u,
-    _Imaginary_ = 213u,
-    _Noreturn_ = 214u,
-    _Static_assert_ = 215u,
-    _Thread_local_ = 216u,
-    _assert_ = 217u,
-    _import_ = 218u,
-    __cdecl_ = 219u,
-    __declspec_ = 220u,
-    __stdcall_ = 221u,
-    __thread_ = 222u,
-    __pragma_ = 223u,
-    __int128_ = 224u,
-    __attribute___ = 225u,
+    rvalue = 199u,
+    inline_ = 200u,
+    register_ = 201u,
+    restrict_ = 202u,
+    signed_ = 203u,
+    sizeof_ = 204u,
+    typedef_ = 205u,
+    unsigned_ = 206u,
+    volatile_ = 207u,
+    _Alignas_ = 208u,
+    _Alignof_ = 209u,
+    _Atomic_ = 210u,
+    _Bool_ = 211u,
+    _Complex_ = 212u,
+    _Generic_ = 213u,
+    _Imaginary_ = 214u,
+    _Noreturn_ = 215u,
+    _Static_assert_ = 216u,
+    _Thread_local_ = 217u,
+    _assert_ = 218u,
+    _import_ = 219u,
+    __cdecl_ = 220u,
+    __declspec_ = 221u,
+    __stdcall_ = 222u,
+    __thread_ = 223u,
+    __pragma_ = 224u,
+    __int128_ = 225u,
+    __attribute___ = 226u,
 };
 
 class FuncExp final : public Expression
@@ -5259,18 +5262,18 @@ struct UnionExp final
 private:
     union _AnonStruct_u
     {
-        char exp[30LLU];
+        char exp[31LLU];
         char integerexp[40LLU];
-        char errorexp[30LLU];
+        char errorexp[31LLU];
         char realexp[48LLU];
         char complexexp[64LLU];
         char symoffexp[64LLU];
-        char stringexp[51LLU];
-        char arrayliteralexp[48LLU];
+        char stringexp[59LLU];
+        char arrayliteralexp[56LLU];
         char assocarrayliteralexp[56LLU];
         char structliteralexp[76LLU];
         char compoundliteralexp[40LLU];
-        char nullexp[30LLU];
+        char nullexp[31LLU];
         char dotvarexp[49LLU];
         char addrexp[40LLU];
         char indexexp[74LLU];
@@ -7137,6 +7140,7 @@ struct Scope final
     void* anchorCounts;
     Identifier* prevAnchor;
     AliasDeclaration* aliasAsg;
+    StructDeclaration* argStruct;
     Dsymbol* search(const Loc& loc, Identifier* ident, Dsymbol*& pscopesym, uint32_t flags = 0u);
     Scope() :
         enclosing(),
@@ -7177,10 +7181,11 @@ struct Scope final
         userAttribDecl(),
         lastdc(),
         prevAnchor(),
-        aliasAsg()
+        aliasAsg(),
+        argStruct()
     {
     }
-    Scope(Scope* enclosing, Module* _module = nullptr, ScopeDsymbol* scopesym = nullptr, FuncDeclaration* func = nullptr, VarDeclaration* varDecl = nullptr, Dsymbol* parent = nullptr, LabelStatement* slabel = nullptr, SwitchStatement* sw = nullptr, Statement* tryBody = nullptr, TryFinallyStatement* tf = nullptr, ScopeGuardStatement* os = nullptr, Statement* sbreak = nullptr, Statement* scontinue = nullptr, ForeachStatement* fes = nullptr, Scope* callsc = nullptr, Dsymbol* inunion = nullptr, bool nofree = false, bool inLoop = false, bool inDefaultArg = false, int32_t intypeof = 0, VarDeclaration* lastVar = nullptr, ErrorSink* eSink = nullptr, Module* minst = nullptr, TemplateInstance* tinst = nullptr, CtorFlow ctorflow = CtorFlow(), AlignDeclaration* aligndecl = nullptr, CPPNamespaceDeclaration* namespace_ = nullptr, LINK linkage = (LINK)1u, CPPMANGLE cppmangle = (CPPMANGLE)0u, PragmaDeclaration* inlining = nullptr, Visibility visibility = Visibility((Visibility::Kind)5u, nullptr), int32_t explicitVisibility = 0, uint64_t stc = 0LLU, DeprecatedDeclaration* depdecl = nullptr, uint32_t bitFields = 0u, UserAttributeDeclaration* userAttribDecl = nullptr, DocComment* lastdc = nullptr, void* anchorCounts = nullptr, Identifier* prevAnchor = nullptr, AliasDeclaration* aliasAsg = nullptr) :
+    Scope(Scope* enclosing, Module* _module = nullptr, ScopeDsymbol* scopesym = nullptr, FuncDeclaration* func = nullptr, VarDeclaration* varDecl = nullptr, Dsymbol* parent = nullptr, LabelStatement* slabel = nullptr, SwitchStatement* sw = nullptr, Statement* tryBody = nullptr, TryFinallyStatement* tf = nullptr, ScopeGuardStatement* os = nullptr, Statement* sbreak = nullptr, Statement* scontinue = nullptr, ForeachStatement* fes = nullptr, Scope* callsc = nullptr, Dsymbol* inunion = nullptr, bool nofree = false, bool inLoop = false, bool inDefaultArg = false, int32_t intypeof = 0, VarDeclaration* lastVar = nullptr, ErrorSink* eSink = nullptr, Module* minst = nullptr, TemplateInstance* tinst = nullptr, CtorFlow ctorflow = CtorFlow(), AlignDeclaration* aligndecl = nullptr, CPPNamespaceDeclaration* namespace_ = nullptr, LINK linkage = (LINK)1u, CPPMANGLE cppmangle = (CPPMANGLE)0u, PragmaDeclaration* inlining = nullptr, Visibility visibility = Visibility((Visibility::Kind)5u, nullptr), int32_t explicitVisibility = 0, uint64_t stc = 0LLU, DeprecatedDeclaration* depdecl = nullptr, uint32_t bitFields = 0u, UserAttributeDeclaration* userAttribDecl = nullptr, DocComment* lastdc = nullptr, void* anchorCounts = nullptr, Identifier* prevAnchor = nullptr, AliasDeclaration* aliasAsg = nullptr, StructDeclaration* argStruct = nullptr) :
         enclosing(enclosing),
         _module(_module),
         scopesym(scopesym),
@@ -7220,7 +7225,8 @@ struct Scope final
         lastdc(lastdc),
         anchorCounts(anchorCounts),
         prevAnchor(prevAnchor),
-        aliasAsg(aliasAsg)
+        aliasAsg(aliasAsg),
+        argStruct(argStruct)
         {}
 };
 

compiler/src/dmd/hdrgen.d

@@ -2888,6 +2888,12 @@ private void expressionPrettyPrint(Expression e, ref OutBuffer buf, ref HdrGenSt
         buf.writestring(e.value.toChars());
     }
 
+    if (e.rvalue)
+        buf.writestring("__rvalue(");
+    scope (success)
+        if (e.rvalue)
+            buf.writeByte(')');
+
     switch (e.op)
     {
         default: