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Support arrays and classes in compile-time OffsetOf.

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Rika Ichinose 2022-06-20 22:41:57 +03:00 committed by florian
parent 63c8e458bb
commit c26f9329b6
1 changed files with 89 additions and 23 deletions
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112
compiler/nmem.pas
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@ -652,39 +652,105 @@ implementation
function taddrnode.simplify(forinline : boolean) : tnode;
function compatible_with_offsetof(res : tdef) : boolean;
begin
result:=(res.typ in [recorddef,objectdef]) and not (is_implicit_pointer_object_type(res))
or (res.typ=arraydef) and not (ado_IsDynamicArray in tarraydef(res).arrayoptions);
end;
var
hsym : tfieldvarsym;
hp : tnode;
fieldoffset : asizeint;
resdef : tdef;
index : int64;
begin
result:=nil;
if left.nodetype<>subscriptn then
exit;
hp:=left;
fieldoffset:=0;
while (hp.nodetype=subscriptn) and (tsubscriptnode(hp).left.resultdef.typ in [recorddef,objectdef]) and
not(is_implicit_pointer_object_type(tsubscriptnode(hp).left.resultdef)) do
begin
hsym:=tsubscriptnode(hp).vs;
if tabstractrecordsymtable(hsym.owner).is_packed then
inc(fieldoffset,hsym.fieldoffset div 8)
{ Attempt to turn
@PSomeType(nil)^.field
or
@SomeType(nil^).fieldA.aryA[3].fieldB.aryB[5]
into a compile-time constant, numerically equal to the offset of the target field in 'SomeType' (and usually cast to 'PtrUint' right away). }
repeat
case hp.nodetype of
subscriptn:
begin
{ Here and below, 'hp<>left' detects non-first iteration,
as the first iteration handles deepest field whose type can be arbitrary: 'c' in @PType(nil)^.a.b.c. }
if (hp<>left) and not compatible_with_offsetof(tsubscriptnode(hp).resultdef) then
exit;
hsym:=tsubscriptnode(hp).vs;
if tabstractrecordsymtable(hsym.owner).is_packed then
begin
if hsym.fieldoffset mod 8<>0 then
exit;
inc(fieldoffset,hsym.fieldoffset div 8);
end
else
inc(fieldoffset,hsym.fieldoffset);
hp:=tsubscriptnode(hp).left;
end;
vecn:
begin
if (tvecnode(hp).right.nodetype<>ordconstn) or
(hp<>left) and not compatible_with_offsetof(tvecnode(hp).resultdef) then
exit;
resdef:=tvecnode(hp).left.resultdef;
if not ((resdef.typ=arraydef) and not (ado_IsDynamicArray in tarraydef(resdef).arrayoptions)) then
exit;
index:=tordconstnode(tvecnode(hp).right).value.svalue;
if not ((index>=tarraydef(resdef).lowrange) and (index<=tarraydef(resdef).highrange)) then
exit;
index:=index-tarraydef(resdef).lowrange;
if ado_IsBitPacked in tarraydef(resdef).arrayoptions then
begin
if index*tarraydef(resdef).elepackedbitsize mod 8<>0 then
exit;
inc(fieldoffset,index*tarraydef(resdef).elepackedbitsize div 8);
end
else
inc(fieldoffset,index*tarraydef(resdef).elesize);
hp:=tvecnode(hp).left;
end;
derefn:
begin
{ @PObjectType(nil)^.fields? }
if tderefnode(hp).left.nodetype=niln then
result:=cpointerconstnode.create(fieldoffset,resultdef);
exit;
end;
typeconvn:
begin
{ @ObjectType(nil^).fields? }
if (ttypeconvnode(hp).left.nodetype=derefn) and
(tderefnode(ttypeconvnode(hp).left).left.nodetype=niln) then
result:=cpointerconstnode.create(fieldoffset,resultdef);
exit;
end;
niln:
{ @ClassType(nil).fields. }
exit(cpointerconstnode.create(fieldoffset,resultdef));
else
inc(fieldoffset,hsym.fieldoffset);
hp:=tsubscriptnode(hp).left;
end;
if not(hp.resultdef.typ in [recorddef,objectdef]) or is_implicit_pointer_object_type(hp.resultdef) then
exit;
if ((hp.nodetype=derefn) and
(tderefnode(hp).left.nodetype=niln)) or
((hp.nodetype=typeconvn) and
(ttypeconvnode(hp).left.nodetype=derefn) and
(tderefnode(ttypeconvnode(hp).left).left.nodetype=niln)) then
begin
if tabstractrecordsymtable(hsym.owner).is_packed then
result:=cpointerconstnode.create(fieldoffset,resultdef)
else
result:=cpointerconstnode.create(fieldoffset,resultdef);
exit;
end;
until false;
end;