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+ parse the data section in the wasm object reader

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This commit is contained in:
Nikolay Nikolov 2023-12-26 17:42:01 +02:00
parent 818b6e6983
commit bbb564437d
1 changed files with 149 additions and 2 deletions
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151
compiler/ogwasm.pas
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@ -2201,6 +2201,56 @@ implementation
result:=true;
end;
function ReadSleb(out v: int64): boolean;
var
b: byte;
shift:integer;
begin
result:=false;
b:=0;
v:=0;
shift:=0;
repeat
if not read(b,1) then
exit;
v:=v or (uint64(b and 127) shl shift);
inc(shift,7);
until (b and 128)=0;
{$ifopt Q+}
{$define overflowon}
{$Q-}
{$endif}
{$ifopt R+}
{$define rangeon}
{$R-}
{$endif}
if (b and 64)<>0 then
v:=v or (high(uint64) shl shift);
result:=true;
end;
{$ifdef overflowon}
{$Q+}
{$undef overflowon}
{$endif}
{$ifdef rangeon}
{$R+}
{$undef rangeon}
{$endif}
function ReadSleb32(out v: int32): boolean;
var
vv: int64;
begin
result:=false;
v:=default(int32);
if not ReadSleb(vv) then
exit;
if (vv>high(int32)) or (vv<low(int32)) then
exit;
v:=vv;
result:=true;
end;
function ReadName(out v: ansistring): boolean;
var
len: uint32;
@ -2224,6 +2274,11 @@ implementation
DataCountSectionRead: Boolean = false;
DataSegments: array of record
Active: Boolean;
MemIdx: uint32;
Len: uint32;
Offset: int32;
DataPos: LongInt;
end;
function ReadCustomSection: Boolean;
@ -2731,8 +2786,35 @@ implementation
end;
function ReadDataSection: Boolean;
function ReadExpr(out ExprV: int32): Boolean;
var
b: Byte;
begin
Result:=False;
if not Read(b,1) then
exit;
if b<>$41 then
begin
InputError('Only i32.const expressions supported');
exit;
end;
if not ReadSleb32(ExprV) then
exit;
if not Read(b,1) then
exit;
if b<>$0B then
begin
InputError('Only single const expressions supported');
exit;
end;
Result:=True;
end;
var
DataCount: uint32;
DataType: Byte;
i: Integer;
begin
Result:=False;
if DataSectionRead then
@ -2751,11 +2833,71 @@ implementation
if Length(DataSegments)<>DataCount then
begin
InputError('Data entries count in the data section do not match the number, specified in the data count section');
exit
exit;
end;
end
else
SetLength(DataSegments,DataCount);
for i:=0 to DataCount-1 do
with DataSegments[i] do
begin
if not read(DataType, 1) then
begin
InputError('Error reading data type of segment from the data section');
exit;
end;
case DataType of
0:
begin
Active:=True;
MemIdx:=0;
if not ReadExpr(Offset) then
begin
InputError('Error reading memory offset of segment from the data section');
exit;
end;
end;
1:
Active:=False;
2:
begin
Active:=True;
if not ReadUleb32(MemIdx) then
begin
InputError('Error reading MemIdx of segment from the data section');
exit;
end;
if not ReadExpr(Offset) then
begin
InputError('Error reading memory offset of segment from the data section');
exit;
end;
end;
else
begin
InputError('Unsupported data type of segment in the data section: ' + tostr(DataType));
exit;
end;
end;
if not ReadUleb32(Len) then
begin
InputError('Error reading data segment length');
exit;
end;
if (AReader.Pos+Len)>(SectionStart+SectionSize) then
begin
InputError('Data segment exceeds the bounds of the data section');
exit;
end;
DataPos:=AReader.Pos;
AReader.Seek(AReader.Pos+Len);
end;
if AReader.Pos<>(SectionStart+SectionSize) then
begin
InputError('Unexpected data section size');
exit;
end;
Result:=true;
end;
function ReadDataCountSection: Boolean;
@ -2840,7 +2982,11 @@ implementation
Byte(wsiCode):
Result := ReadCodeSection;
Byte(wsiData):
Result := ReadDataSection;
if not ReadDataSection then
begin
InputError('Error reading the data section');
exit;
end;
Byte(wsiDataCount):
begin
if not ReadDataCountSection then
@ -2948,3 +3094,4 @@ initialization
RegisterAssembler(as_wasm32_wasm_info,TWasmAssembler);
{$endif wasm32}
end.