x64: pass by-value dynamic arrays as pointer value on FPC 3+#315
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x64: pass by-value dynamic arrays as pointer value on FPC 3+#315TetzkatLipHoka wants to merge 1 commit into
TetzkatLipHoka wants to merge 1 commit into
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The classic x64 path passed by-value dynamic array parameters as the
ADDRESS of the variable slot on FPC ({$IFDEF FPC} FVar.Dta instead of
FVar.Dta^), a leftover from an FPC 2.4-era fix. On FPC 3.x x86_64-linux the
callee then reads garbage instead of the array (Length() returns random
values, element access crashes with an access violation).
A dynamic array IS a pointer on every current target: pass its value, like
the Delphi branch always did. The 2.4 behavior is kept behind
{$IF FPC_VERSION < 3}.
Repro (fails on master with the FPC-compilation fixes applied, passes with
this change; fpc 3.2.2 x86_64-linux):
host: function DynTake(const A: TArr): Integer; // TArr = array of string
script: SetLength(a, 2); a[0] := 'x'; a[1] := 'y'; n := DynTake(a);
Delphi Win64 classic path unchanged and re-verified.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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The classic x64 path passed by-value dynamic array parameters as the
ADDRESS of the variable slot on FPC ({$IFDEF FPC} FVar.Dta instead of
FVar.Dta^), a leftover from an FPC 2.4-era fix. On FPC 3.x x86_64-linux the
callee then reads garbage instead of the array (Length() returns random
values, element access crashes with an access violation).
A dynamic array IS a pointer on every current target: pass its value, like
the Delphi branch always did. The 2.4 behavior is kept behind
{$IF FPC_VERSION < 3}.
Repro (fails on master with the FPC-compilation fixes applied, passes with
this change; fpc 3.2.2 x86_64-linux):
host: function DynTake(const A: TArr): Integer; // TArr = array of string
script: SetLength(a, 2); a[0] := 'x'; a[1] := 'y'; n := DynTake(a);
Delphi Win64 classic path unchanged and re-verified.
Related: #198 (the FPC access violation with dynamic arrays crossing the import boundary).
🤖 Generated with Claude Code