[fpc-pascal] Procedural generics question

Benito van der Zander benito at benibela.de
Tue Aug 25 23:47:35 CEST 2020


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/
> _______________________________________________
> fpc-pascal maillist  -  fpc-pascal at lists.freepascal.org
> https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
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