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* optimization in tcg386.g_intf_wrapper: use the much more efficient case 1

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for virtual methods, that use the register calling convention, but have at
  least one free register (i.e. not used as a parameter and not required to be
  preserved by the function)

git-svn-id: trunk@25830 -
This commit is contained in:
nickysn 2013-10-19 17:40:38 +00:00
parent bfd31e7516
commit 378afb69b2
1 changed files with 36 additions and 15 deletions

51
compiler/i386/cgcpu.pas
View File

@ -30,7 +30,7 @@ unit cgcpu;
cgbase,cgobj,cg64f32,cgx86,
aasmbase,aasmtai,aasmdata,aasmcpu,
cpubase,parabase,cgutils,
symconst,symdef
symconst,symdef,symsym
;
type
@ -616,17 +616,17 @@ unit cgcpu;
possible calling conventions:
default stdcall cdecl pascal register
default(0): OK OK OK OK OK
virtual(1): OK OK OK OK OK(2)
virtual(1): OK OK OK OK OK(2 or 1)
(0):
set self parameter to correct value
jmp mangledname
(1): The wrapper code use %eax to reach the virtual method address
(1): The wrapper code use %ecx to reach the virtual method address
set self to correct value
move self,%eax
mov 0(%eax),%eax ; load vmt
jmp vmtoffs(%eax) ; method offs
mov 0(%eax),%ecx ; load vmt
jmp vmtoffs(%ecx) ; method offs
(2): Virtual use values pushed on stack to reach the method address
so the following code be generated:
@ -642,6 +642,27 @@ unit cgcpu;
}
{ returns whether ECX is used as a parameter }
function is_ecx_used: boolean;
var
i: Integer;
hp: tparavarsym;
paraloc: PCGParaLocation;
begin
for i:=0 to procdef.paras.count-1 do
begin
hp:=tparavarsym(procdef.paras[i]);
paraloc:=hp.paraloc[calleeside].Location;
while paraloc<>nil do
begin
if (paraloc^.Loc=LOC_REGISTER) and (getsupreg(paraloc^.register)=RS_ECX) then
exit(true);
paraloc:=paraloc^.Next;
end;
end;
Result:=false;
end;
procedure getselftoeax(offs: longint);
var
href : treference;
@ -660,23 +681,23 @@ unit cgcpu;
end;
end;
procedure loadvmttoeax;
procedure loadvmtto(reg: tregister);
var
href : treference;
begin
{ mov 0(%eax),%eax ; load vmt}
{ mov 0(%eax),%reg ; load vmt}
reference_reset_base(href,NR_EAX,0,4);
cg.a_load_ref_reg(list,OS_ADDR,OS_ADDR,href,NR_EAX);
cg.a_load_ref_reg(list,OS_ADDR,OS_ADDR,href,reg);
end;
procedure op_oneaxmethodaddr(op: TAsmOp);
procedure op_onregmethodaddr(op: TAsmOp; reg: tregister);
var
href : treference;
begin
if (procdef.extnumber=$ffff) then
Internalerror(200006139);
{ call/jmp vmtoffs(%eax) ; method offs }
reference_reset_base(href,NR_EAX,tobjectdef(procdef.struct).vmtmethodoffset(procdef.extnumber),4);
{ call/jmp vmtoffs(%reg) ; method offs }
reference_reset_base(href,reg,tobjectdef(procdef.struct).vmtmethodoffset(procdef.extnumber),4);
list.concat(taicpu.op_ref(op,S_L,href));
end;
@ -724,13 +745,13 @@ unit cgcpu;
if (po_virtualmethod in procdef.procoptions) and
not is_objectpascal_helper(procdef.struct) then
begin
if (procdef.proccalloption=pocall_register) then
if (procdef.proccalloption=pocall_register) and is_ecx_used then
begin
{ case 2 }
list.concat(taicpu.op_reg(A_PUSH,S_L,NR_EBX)); { allocate space for address}
list.concat(taicpu.op_reg(A_PUSH,S_L,NR_EAX));
getselftoeax(8);
loadvmttoeax;
loadvmtto(NR_EAX);
loadmethodoffstoeax;
{ mov %eax,4(%esp) }
reference_reset_base(href,NR_ESP,4,4);
@ -744,8 +765,8 @@ unit cgcpu;
begin
{ case 1 }
getselftoeax(0);
loadvmttoeax;
op_oneaxmethodaddr(A_JMP);
loadvmtto(NR_ECX);
op_onregmethodaddr(A_JMP,NR_ECX);
end;
end
{ case 0 }