The TypeInfo function checks the code during run-time thus the generated
code is 'bloated'. Better use the compiler intrinsic GetTypeKind.
{$mode objfpc}
uses
typinfo;
generic procedure Add<T>;
begin
if GetTypeKind(T) = tkInteger then WriteLn('an integer');
if GetTypeKind(T) = tkString then WriteLn('a string');
end;
begin
specialize Add<Integer>;
specialize Add<String>;
end.
for 'specialize Add<Integer>;' the following code is generated:
# [46] if GetTypeKind(T) = tkInteger then WriteLn('an integer');
call fpc_get_output
movq %rax,%rbx
leaq _$VT$_Ld1(%rip),%r8
movq %rbx,%rdx
movl $0,%ecx
call fpc_write_text_shortstr
call fpc_iocheck
movq %rbx,%rcx
call fpc_writeln_end
call fpc_iocheck
# [48] end;
Am Di., 25. Aug. 2020 um 23:54 Uhr schrieb Benito van der Zander via
fpc-pascal <fpc-pascal@lists.freepascal.org>:
> Hi,
>
> that is generating rather odd code (r40721)
>
> project1.lpr:9 begin
> 0000000000401090 55 push %rbp
> 0000000000401091 4889e5 mov %rsp,%rbp
> 0000000000401094 488d6424f0 lea -0x10(%rsp),%rsp
> 0000000000401099 48895df8 mov %rbx,-0x8(%rbp)
> project1.lpr:10 if TypeInfo(T) =
> TypeInfo(Integer) then WriteLn('an integer');
> 000000000040109D 488d1584af0700 lea 0x7af84(%rip),%rdx
> # 0x47c028 <RTTI_$SYSTEM_$$_LONGINT>
> 00000000004010A4 488d057daf0700 lea 0x7af7d(%rip),%rax
> # 0x47c028 <RTTI_$SYSTEM_$$_LONGINT>
> 00000000004010AB 4839c2 cmp %rax,%rdx
> 00000000004010AE 752b jne 0x4010db
> <ADD$1$CRC713F463B+75>
> 00000000004010B0 e8cbcf0100 callq 0x41e080 <fpc_get_output>
> 00000000004010B5 4889c3 mov %rax,%rbx
> 00000000004010B8 488d15412f0600 lea 0x62f41(%rip),%rdx
> # 0x464000 <_$PROJECT1$_Ld1>
> 00000000004010BF 4889de mov %rbx,%rsi
> 00000000004010C2 31ff xor %edi,%edi
> 00000000004010C4 e867d30100 callq 0x41e430
> <fpc_write_text_shortstr>
> 00000000004010C9 e8d2700100 callq 0x4181a0 <fpc_iocheck>
> 00000000004010CE 4889df mov %rbx,%rdi
> 00000000004010D1 e85ad20100 callq 0x41e330 <fpc_writeln_end>
> 00000000004010D6 e8c5700100 callq 0x4181a0 <fpc_iocheck>
> project1.lpr:11 if TypeInfo(T) =
> TypeInfo(String) then WriteLn('a string');
> 00000000004010DB 488d0546af0700 lea 0x7af46(%rip),%rax
> # 0x47c028 <RTTI_$SYSTEM_$$_LONGINT>
> 00000000004010E2 488d1537b20700 lea 0x7b237(%rip),%rdx
> # 0x47c320 <RTTI_$SYSTEM_$$_SHORTSTRING>
> 00000000004010E9 4839d0 cmp %rdx,%rax
> 00000000004010EC 752b jne 0x401119
> <ADD$1$CRC713F463B+137>
> 00000000004010EE e88dcf0100 callq 0x41e080 <fpc_get_output>
> 00000000004010F3 4889c3 mov %rax,%rbx
> 00000000004010F6 488d15132f0600 lea 0x62f13(%rip),%rdx
> # 0x464010 <_$PROJECT1$_Ld2>
> 00000000004010FD 4889de mov %rbx,%rsi
> 0000000000401100 31ff xor %edi,%edi
> 0000000000401102 e829d30100 callq 0x41e430
> <fpc_write_text_shortstr>
> 0000000000401107 e894700100 callq 0x4181a0 <fpc_iocheck>
> 000000000040110C 4889df mov %rbx,%rdi
> 000000000040110F e81cd20100 callq 0x41e330 <fpc_writeln_end>
> 0000000000401114 e887700100 callq 0x4181a0 <fpc_iocheck>
> project1.lpr:12 end;
>
> The compiler should know everything about TypeInfo(T) and optimize it away
> where possible
>
> Cheers,
> Benito
> On 25.08.20 04:32, leledumbo via fpc-pascal wrote:
>
> I remember something like this in RTTI though but can't find it in your
>
> docs yet for generics.
>
> {$mode objfpc}
>
> uses
> typinfo;
>
> generic procedure Add<T>;
> begin
> if TypeInfo(T) = TypeInfo(Integer) then WriteLn('an integer');
> if TypeInfo(T) = TypeInfo(String) then WriteLn('a string');
> end;
>
> begin
> specialize Add<Integer>;
> specialize Add<String>;
> end.
>
>
>
> --
> Sent from: http://free-pascal-general.1045716.n5.nabble.com/
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