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+ Encode(U/S)leb128 take now a third parameter to force that the constant has a certain minimum size

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+ tai_const has a new field fixed_size which is used to fix the size of an s/uleb128. This is needed to ensure convergence during assembling when calculating offsets

git-svn-id: branches/debug_eh@42255 -
This commit is contained in:
florian 2019-06-20 17:13:28 +00:00
parent adb8e1b76c
commit 1ed0000ae8
4 changed files with 59 additions and 14 deletions
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45
compiler/aasmtai.pas
View File

@ -653,6 +653,9 @@ interface
symofs,
value : int64;
consttype : taiconst_type;
{ sleb128 and uleb128 values have a varying length, by calling FixSize their size can be fixed
to avoid that other offsets need to be changed. The value to write is stored in fixed_size }
fixed_size : byte;
{ we use for the 128bit int64/qword for now because I can't imagine a
case where we need 128 bit now (FK) }
constructor Create(_typ:taiconst_type;_value : int64);
@ -707,6 +710,9 @@ interface
procedure derefimpl;override;
function getcopy:tlinkedlistitem;override;
function size:longint;
{ sleb128 and uleb128 values have a varying length, by calling FixSize their size can be fixed
to avoid that other offsets need to be changed. The value to write is stored in fixed_size }
Procedure FixSize;
end;
{ floating point const }
@ -2002,9 +2008,31 @@ implementation
else
result:=sizeof(pint);
aitconst_uleb128bit :
result:=LengthUleb128(qword(value));
begin
if fixed_size>0 then
result:=fixed_size
else if sym=nil then
begin
FixSize;
result:=fixed_size;
end
else
{ worst case }
result:=sizeof(pint)+2;
end;
aitconst_sleb128bit :
result:=LengthSleb128(value);
begin
if fixed_size>0 then
result:=fixed_size
else if sym=nil then
begin
FixSize;
result:=fixed_size;
end
else
{ worst case }
result:=sizeof(pint)+2;
end;
aitconst_half16bit,
aitconst_gs:
result:=2;
@ -2024,6 +2052,19 @@ implementation
end;
procedure tai_const.FixSize;
begin
case consttype of
aitconst_uleb128bit:
fixed_size:=LengthUleb128(qword(value));
aitconst_sleb128bit:
fixed_size:=LengthSleb128(value);
else
Internalerror(2019030301);
end;
end;
{****************************************************************************
TAI_realconst
****************************************************************************}

6
compiler/aggas.pas
View File

@ -1,4 +1,4 @@
{
{
Copyright (c) 1998-2006 by the Free Pascal team
This unit implements the generic part of the GNU assembler
@ -586,7 +586,7 @@ implementation
i,len : longint;
buf : array[0..63] of byte;
begin
len:=EncodeUleb128(a,buf);
len:=EncodeUleb128(a,buf,0);
for i:=0 to len-1 do
begin
if (i > 0) then
@ -634,7 +634,7 @@ implementation
i,len : longint;
buf : array[0..255] of byte;
begin
len:=EncodeSleb128(a,buf);
len:=EncodeSleb128(a,buf,0);
for i:=0 to len-1 do
begin
if (i > 0) then

10
compiler/assemble.pas
View File

@ -1767,6 +1767,8 @@ Implementation
else
Tai_const(hp).value:=objsymend.address-objsym.address+Tai_const(hp).symofs;
end;
if (Tai_const(hp).consttype in [aitconst_uleb128bit,aitconst_sleb128bit]) then
Tai_const(hp).fixsize;
ObjData.alloc(tai_const(hp).size);
end;
ait_section:
@ -2035,11 +2037,13 @@ Implementation
aitconst_uleb128bit,
aitconst_sleb128bit :
begin
if Tai_const(hp).fixed_size=0 then
Internalerror(2019030302);
if tai_const(hp).consttype=aitconst_uleb128bit then
leblen:=EncodeUleb128(qword(Tai_const(hp).value),lebbuf)
leblen:=EncodeUleb128(qword(Tai_const(hp).value),lebbuf,Tai_const(hp).fixed_size)
else
leblen:=EncodeSleb128(Tai_const(hp).value,lebbuf);
if leblen<>tai_const(hp).size then
leblen:=EncodeSleb128(Tai_const(hp).value,lebbuf,Tai_const(hp).fixed_size);
if leblen<>tai_const(hp).fixed_size then
internalerror(200709271);
ObjData.writebytes(lebbuf,leblen);
end;

12
compiler/cutils.pas
View File

@ -182,8 +182,8 @@ interface
function LengthUleb128(a: qword) : byte;
function LengthSleb128(a: int64) : byte;
function EncodeUleb128(a: qword;out buf) : byte;
function EncodeSleb128(a: int64;out buf) : byte;
function EncodeUleb128(a: qword;out buf;len: byte) : byte;
function EncodeSleb128(a: int64;out buf;len: byte) : byte;
{ hide Sysutils.ExecuteProcess in units using this one after SysUtils}
const
@ -1672,7 +1672,7 @@ implementation
end;
function EncodeUleb128(a: qword;out buf) : byte;
function EncodeUleb128(a: qword;out buf;len : byte) : byte;
var
b: byte;
pbuf : pbyte;
@ -1687,13 +1687,13 @@ implementation
pbuf^:=b;
inc(pbuf);
inc(result);
if a=0 then
if (a=0) and (result>=len) then
break;
until false;
end;
function EncodeSleb128(a: int64;out buf) : byte;
function EncodeSleb128(a: int64;out buf;len : byte) : byte;
var
b, size: byte;
more: boolean;
@ -1707,7 +1707,7 @@ implementation
b := a and $7f;
a := SarInt64(a, 7);
if (
if (result+1>=len) and (
((a = 0) and (b and $40 = 0)) or
((a = -1) and (b and $40 <> 0))
) then