Mercurial > projects > ddmd
annotate dmd/NullExp.d @ 187:b0d41ff5e0df
Added expandability scheme outlined in http://www.dsource.org/forums/viewtopic.php?t=5659&sid=6f2150ff5b0bffcd47512a6a7608d218
| author | Abscissa |
|---|---|
| date | Tue, 07 Jun 2011 23:37:34 -0400 |
| parents | e3afd1303184 |
| children |
| rev | line source |
|---|---|
| 72 | 1 module dmd.NullExp; |
| 2 | |
| 114 | 3 import dmd.common; |
| 72 | 4 import dmd.Expression; |
| 5 import dmd.backend.elem; | |
| 6 import dmd.InterState; | |
| 7 import dmd.MATCH; | |
| 8 import dmd.Type; | |
| 9 import dmd.TY; | |
| 10 import dmd.TypeTypedef; | |
| 11 import dmd.OutBuffer; | |
| 12 import dmd.Loc; | |
| 13 import dmd.Scope; | |
| 14 import dmd.IRState; | |
| 15 import dmd.HdrGenState; | |
| 16 import dmd.TOK; | |
| 17 import dmd.backend.dt_t; | |
| 18 import dmd.backend.Util; | |
| 19 | |
|
187
b0d41ff5e0df
Added expandability scheme outlined in http://www.dsource.org/forums/viewtopic.php?t=5659&sid=6f2150ff5b0bffcd47512a6a7608d218
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20 import dmd.DDMDExtensions; |
|
b0d41ff5e0df
Added expandability scheme outlined in http://www.dsource.org/forums/viewtopic.php?t=5659&sid=6f2150ff5b0bffcd47512a6a7608d218
Abscissa
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21 |
| 0 | 22 class NullExp : Expression |
| 23 { | |
|
187
b0d41ff5e0df
Added expandability scheme outlined in http://www.dsource.org/forums/viewtopic.php?t=5659&sid=6f2150ff5b0bffcd47512a6a7608d218
Abscissa
parents:
178
diff
changeset
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24 mixin insertMemberExtension!(typeof(this)); |
|
b0d41ff5e0df
Added expandability scheme outlined in http://www.dsource.org/forums/viewtopic.php?t=5659&sid=6f2150ff5b0bffcd47512a6a7608d218
Abscissa
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changeset
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25 |
| 0 | 26 ubyte committed; |
| 27 | |
| 135 | 28 this(Loc loc, Type type = null) |
| 72 | 29 { |
| 178 | 30 register(); |
| 0 | 31 super(loc, TOK.TOKnull, NullExp.sizeof); |
| 135 | 32 this.type = type; |
| 0 | 33 } |
| 34 | |
| 72 | 35 override Expression semantic(Scope sc) |
| 0 | 36 { |
| 72 | 37 version (LOGSEMANTIC) { |
| 38 printf("NullExp.semantic('%s')\n", toChars()); | |
| 39 } | |
| 40 // null is the same as (void*)0 | |
| 41 if (!type) | |
| 42 type = Type.tvoid.pointerTo(); | |
| 43 | |
| 0 | 44 return this; |
| 45 } | |
| 46 | |
| 72 | 47 override bool isBool(bool result) |
| 0 | 48 { |
| 49 assert(false); | |
| 50 } | |
| 51 | |
| 72 | 52 override int isConst() |
| 0 | 53 { |
| 63 | 54 return 0; |
| 0 | 55 } |
| 56 | |
| 72 | 57 override void toCBuffer(OutBuffer buf, HdrGenState* hgs) |
| 0 | 58 { |
| 59 buf.writestring("null"); | |
| 60 } | |
| 61 | |
| 72 | 62 override void toMangleBuffer(OutBuffer buf) |
| 0 | 63 { |
| 64 | 64 buf.writeByte('n'); |
| 0 | 65 } |
| 66 | |
| 72 | 67 override MATCH implicitConvTo(Type t) |
| 0 | 68 { |
| 72 | 69 static if (false) { |
| 70 printf("NullExp.implicitConvTo(this=%s, type=%s, t=%s, committed = %d)\n", | |
| 71 toChars(), type.toChars(), t.toChars(), committed); | |
| 72 } | |
| 73 if (this.type.equals(t)) | |
| 74 return MATCH.MATCHexact; | |
| 75 | |
| 76 /* Allow implicit conversions from invariant to mutable|const, | |
| 77 * and mutable to invariant. It works because, after all, a null | |
| 78 * doesn't actually point to anything. | |
| 79 */ | |
| 80 if (t.invariantOf().equals(type.invariantOf())) | |
| 81 return MATCH.MATCHconst; | |
| 82 | |
| 83 // null implicitly converts to any pointer type or dynamic array | |
| 84 if (type.ty == TY.Tpointer && type.nextOf().ty == TY.Tvoid) | |
| 85 { | |
| 86 if (t.ty == TY.Ttypedef) | |
| 87 t = (cast(TypeTypedef)t).sym.basetype; | |
| 88 if (t.ty == TY.Tpointer || t.ty == TY.Tarray || | |
| 89 t.ty == TY.Taarray || t.ty == TY.Tclass || | |
| 90 t.ty == TY.Tdelegate) | |
| 91 { | |
| 92 return committed ? MATCH.MATCHconvert : MATCH.MATCHexact; | |
| 93 } | |
| 94 } | |
| 95 | |
| 0 | 96 return Expression.implicitConvTo(t); |
| 97 } | |
| 98 | |
| 72 | 99 override Expression castTo(Scope sc, Type t) |
| 0 | 100 { |
| 72 | 101 NullExp e; |
| 102 Type tb; | |
| 103 | |
| 104 //printf("NullExp::castTo(t = %p)\n", t); | |
| 105 if (type is t) | |
| 106 { | |
| 107 committed = 1; | |
| 108 return this; | |
| 109 } | |
| 110 | |
| 111 e = cast(NullExp)copy(); | |
| 112 e.committed = 1; | |
| 113 tb = t.toBasetype(); | |
| 114 e.type = type.toBasetype(); | |
| 115 | |
| 116 if (tb !is e.type) | |
| 117 { | |
| 118 // null implicitly converts to any pointer type or dynamic array | |
| 119 if (e.type.ty == TY.Tpointer && e.type.nextOf().ty == TY.Tvoid && | |
| 120 (tb.ty == TY.Tpointer || tb.ty == TY.Tarray || tb.ty == TY.Taarray || | |
| 121 tb.ty == TY.Tdelegate)) | |
| 122 { | |
| 123 static if (false) { | |
| 124 if (tb.ty == TY.Tdelegate) | |
| 125 { | |
| 126 TypeDelegate td = cast(TypeDelegate)tb; | |
| 127 TypeFunction tf = cast(TypeFunction)td.nextOf(); | |
| 128 | |
| 129 if (!tf.varargs && !(tf.arguments && tf.arguments.dim)) | |
| 130 { | |
| 131 return Expression.castTo(sc, t); | |
| 132 } | |
| 133 } | |
| 134 } | |
| 135 } | |
| 136 else | |
| 137 { | |
| 138 return e.Expression.castTo(sc, t); | |
| 139 } | |
| 140 } | |
| 141 e.type = t; | |
| 0 | 142 return e; |
| 143 } | |
| 144 | |
| 72 | 145 override Expression interpret(InterState istate) |
| 0 | 146 { |
| 123 | 147 return this; |
| 0 | 148 } |
| 149 | |
| 72 | 150 override elem* toElem(IRState* irs) |
| 0 | 151 { |
| 152 return el_long(type.totym(), 0); | |
| 153 } | |
| 154 | |
| 72 | 155 override dt_t** toDt(dt_t** pdt) |
| 0 | 156 { |
| 72 | 157 assert(type); |
| 0 | 158 return dtnzeros(pdt, cast(uint)type.size()); |
| 159 } | |
| 160 } | |
| 161 |