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ExceptObject was missing, though ExceptAddr was not

Symptom

try
  raise EConvertError.Create('m');
except
  WriteLn('cls:' + ExceptObject.ClassName);
end;



pascal26:64: error: undefined variable (ExceptObject)
  near: except W  cls:  ExceptObject >>>  ClassName

FPC compiles and runs it. The shape matters more than it looks: a bare except — no on E: T do binding — is how FPC code that predates the on syntax reads its exception, and ExceptObject is the only door into it. The same call is how a routine called from a handler sees what is in flight without the handler threading it through a parameter.

Why the gap existed

ExceptAddr was implemented (bug-pascal-exceptaddr-returns-nil) by adding an __pxxExceptAddr intrinsic over BSS_EXC_ADDR. Its sibling slot, BSS_EXC_OBJ, was already being written by every raise stub on every backend and already being read by IR_EXC_STORE — that read is exactly what binds E in on E: T do. So the value was present, the load was present, and only the name was missing. This is the double-case shape normalise-dont-special-case.md warns about: one of two arms got built, and the unbuilt one is the one that stayed broken.

Fix

Four small pieces, no new IR op and no backend change:

  1. AN_EXCEPTOBJ = 99 (defs.inc) — the twin of AN_EXCEPTADDR = 89.
  2. __pxxExceptObject in pasparser_expr.inc, written as a copy of the __pxxExceptAddr arm beside it: reserved prefix, optional parens, EnableExceptionRuntime so a unit may read the slot without ever raising.
  3. Lowering in ir.inc: IR_EXC_STORE with the slot selector left at its default, because IRExcStoreSlot's IRC = 0 case is already BSS_EXC_OBJ. The arm is three lines and costs the six backends nothing — the same property that let the signal intrinsics land free.
  4. function ExceptObject: TObject in sysutils.pas, one line over the intrinsic.

The intrinsic stays untyped (tyPointer) and the cast to TObject happens in the RTL wrapper. That is deliberate: it keeps the parser from needing to know a class it otherwise has no reason to know, and it is the same division ExceptAddr/__pxxExceptAddr already uses.

Also corrected a stale comment above ExceptAddr's declaration, which still described it as a nil stub with the honest fix "filed" — it had already landed.

Verification

test/test_exceptobject_intrinsic.pas, wired into test-core, and byte-identical to fpc 3.2.2 across six shapes:

row shape
idle: nil no exception in flight → nil
bare: bare except, no binding
bound: + same: True inside on e: Exception do, ExceptObject = e
report: read from a routine the handler CALLS
in: / out: nested, where the inner handler raises a new exception

Gate: make compiler/pascal26 fixedpoint + tools/gate.sh quick GREEN.

Not done

AcquireExceptionObject / ReleaseExceptionObject are still absent. They are a different question — they hand ownership of the object out of the handler, which is about the raise machinery's lifetime rules rather than about naming a slot that already exists. Nothing in the corpus has asked for them yet; file when something does.