`trees.nim` can import `bnode` — nothing in `bnode`'s import closure reaches
`trees`, checked rather than assumed — so the shared helpers move to `AnyNode`
instead of being reimplemented behind the seam: `getMagic`, `whichPragma`,
`getRoot`, `isDeepConstExpr`, plus `ccgutils.stmtsContainPragma`. That unblocks
three more codegen procs, `canMove`, `notYetAlive` and `ifSwitchSplitPoint`,
which needed them and nothing else.
`stmtsContainPragma` could not simply stay `getPragmaStmt(n, w) != nil`, and
the reason is worth recording because it will recur: a proc that returns a node
OR NIL is the one shape the seam cannot serve. `.bif` spells a missing child as
a `DotToken` *inside* a tree; there is no nil token to hand back as a return
value and a `Cursor` is not nilable. So the predicate is split out — and,
because that leaves two copies of one traversal, `grindPredicates` now asserts
the two agree at every node instead of trusting them to.
Measuring the answers, not just the agreement, again earned its keep. Six of
the new checks came back with a wide spread (`getMagic` 7780 non-`mNone` over
many magics, `getRoot` 19506 non-nil syms compared by identity, `isDeepConstExpr`
7917 true, `notYetAlive` 9653 true). Two came back CONSTANT — `stmtsContainPragma`
false at all 67_721 nodes and `ifSwitchSplitPoint` zero at all 24 — because
nothing in the closure uses `{.linearScanEnd.}` or `{.computedGoto.}`. Both are
now exercised on both answers by shapes added to `tools/icgrind`. A check that
grades a constant is indistinguishable from a passing check in the output, so
this only shows up if the distribution is looked at.
Verified: grind clean over the whole `--ic:on` closure (67_857 nodes, 0
disagreements); the target's `--ic:on` output matches its `nim c` output;
215/215 byte-identical `.c` against HEAD on the default path; all four build
configurations compile.
Sabotaging `bnode.secondSon` — an accessor the lockstep walk does NOT itself
use, since it descends by index — is caught only by this layer, and is: it
fires on `getRoot`, `isDeepConstExpr`, `reifiedOpenArray` and
`skipTrivialIndirections`.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XEF7FJvUkGKvG9LSGuEaNR
The same treatment the `PNode` side just got, for the reason that applies to
types: `t[0]` is the return type, the base class, the index type or the generic
head depending on the kind, and the subscript says none of that. Every child
access in the cgen files that has a named accessor now uses it — `baseClass`
for the eleven object-hierarchy walks, `elementType` for the seq/openArray
element, `returnType`, `genericHead`, `firstGenericParam` — and the two loops
that walked a type's children become `paramTypes` and `kids`.
Left indexed on purpose: a parameter reached by ARGUMENT position
(`typ[i]` in ccgcalls/ccgstmts), a tuple field, and a generic parameter at an
explicit index. There the index is the clearest thing to write.
Every substitution is exact rather than merely close. `[]` with index 0 is
unconditionally `sonsImpl[0]`, so `baseClass`/`returnType`/`genericHead` cannot
diverge; `elementType` is `sonsImpl[^1]` and is used only where the type has a
single son; `paramTypes` and `kids` are literally the loops they replace.
`ast.sons(t: PType)` gets the warning it has been missing. Despite the name it
is not the counterpart of the `sons` ITERATOR over a `PNode`: it returns the
raw seq, and a `tyProc` keeps its parameter types in `n`, so that seq holds
only the return type while `[]`/`len`/`kids` route parameters through
`n[i].sym.typ`. `for x in t.sons` therefore compiles, reads exactly like the
`PNode` idiom, and visits a different set of types — which is what
`ccgutils.encodeType` would have started doing had it been converted to `sons`
rather than `kids`. Marking the proc deprecated and rebuilding shows one call
site in the whole compiler (`previouslyInferred`), so the trap is latent, not
active.
`bnode.nim` also records that there is deliberately no `BType` beside `BNode`:
types stay `PType`s under `newIcBackend` — `BNode.typ` returns one — because
the backend asks them questions (`skipTypes`, `getSize`, `lengthOrd`, the
record walk over `t.n`) that a raw cursor cannot answer.
Pure refactor: all 216 generated `.c` files byte-identical to the parent commit.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FMyRHByv7hhaQJ4Pa1bHbE
Completes the vocabulary migration started with `BNode`: every child READ in
the cgen files now goes through an accessor that a `.bif` `Cursor` can also
serve, so flipping `newIcBackend` is a matter of implementing the vocabulary
rather than rewriting call sites.
* constant indices -> `firstSon` / `secondSon` / `lastSon` / `son(n, k)`,
including the `namePos`/`paramsPos`/`bodyPos`/... slot reads;
* indexed loops -> `sons` / `sonsFrom` / `sonsButLast` and the index-yielding
`isons` / `isonsButLast`. `for i in 0..<n.len: n[i]` is quadratic once
`BNode` is a `Cursor`, because reaching child `i` costs one `skip` per
preceding SUBTREE;
* `n.len == 0` / `> 0` on a node -> `hasSons`, which does not count.
`astdef` gains `sonsButLast(n, count)` and `isonsButLast` — the
`nkOfBranch`/`nkExceptBranch` shape, whose last child is the branch body, and
with `count = 2` the `nkVarTuple`/`nkIdentDefs` shape.
Three places needed more than a rename:
* the C++/goto/setjmp try generators re-subscripted `t[i]` up to ten times
per iteration of their `while i < t.len` walk; the branch node is now
hoisted once per step;
* `genParams` scans the arguments BACKWARDS to decide which need a temporary,
which a `Cursor` cannot do at all. It materializes them in one forward pass
and indexes that — the same order of work, since `needTmp` already
allocates per call;
* loops that stop at a computed position (`casePos`, `until`, `splitPoint`)
walk forward and break instead of counting up to the bound.
What is left is exactly what a `Cursor` backend will not do: writes that build
a fresh `nkProcDef`, and subscripts of a `PType`, `string`, `seq` or `Table`.
`bnode.nim` records the invariant and the `PType` trap — `ast.sons(t: PType)`
is a proc returning `var TTypeSeq`, not the iterator of the same name — which
the type checker enforces, since the `firstSon`/`secondSon`/`lastSon`/`son`
family exists for `PNode` only.
Pure refactor, verified as one: all 216 generated `.c` files byte-identical to
the parent commit; metamorphic IC 16/16; icSuite 19/19 fragments; categories
gc 78, arc 140, destructor 97, closure 23, iter 71, trmacros 6, cpp 50,
exception 47, casestmt 16 with one pre-existing environmental failure
(tests/cpp/tasync_cpp.nim: `cannot open file: jester`).
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FMyRHByv7hhaQJ4Pa1bHbE
`for i in k..<n.len: ... n[i] ...` is the dominant shape for walking a `PNode`'s
children in the code generator: 41 such loops across the cgen files, and 777
indexed node accesses in total. It reads worse than iterating, it bounds-checks
every subscript, and it is quadratic the moment the backend reads children off a
NIF `Cursor` rather than a materialised tree (a child is `firstSon` plus one
`skip` per preceding sibling, and `skip` steps over a whole subtree).
31 of the 41 are converted:
* 20 to `sons`/`sonsFrom` — the index only ever subscripted `n`.
* 9 to `isons`, which now takes a `start` index (defaulting to 0, so its eight
existing call sites are unchanged). These genuinely need `i`: a parallel index
into the routine's `PType` (`typ.n[i]`, `typ[i]`), a `needTmp[i-1]` lookup, an
`i == field.position` test, `$i` in a generated struct name, or the index
passed straight to `genOtherArg`.
* 2 to `sonsFrom` with a variable start (`firstParam`, `offset`).
`sonsFrom` is new, next to `sons`/`isons` in astdef.
The remaining 10 are deliberate. Eight are not `PNode` at all — `varargs[Snippet]`,
`seq[PSym]`, `string`, and `PType`, where `sons` is a `proc ...: var TTypeSeq`
rather than an iterator, so a blind rewrite would compile into something quite
different. Two iterate `0..<it.len-1`, excluding the last child, which no
iterator expresses cleanly.
Pure refactor, and verified as one: all 219 generated `.c` files of a 219-module
program and the linked binary are byte-identical to the parent commit. That is
the bar that matters here, because the index arithmetic (`i-1`, `i == position`,
`$i`) is the easy thing to get wrong. It also caught a real slip on the way:
`genFieldCheck` reassigns its loop variable, which a `for` binding cannot do.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The rule deciding which integer identifies a backend-minted symbol —
content-derived `disamb` for a lifted hook (`setHookDisamb`), `itemId.item`
otherwise — was written out at three sites: `mangleProcNameExt` and
`ccgutils.makeUnique` for the C name, `ast2nif.toNifSymName` for the NIF name,
each carrying its own copy of the ten-line rationale.
They drifted, which is exactly cce17461d: `toNifSymName` lacked the hook
exception, so the loader overwrote a content-derived value and two unrelated
`=destroy` hooks collided on one C name (C accepted the mistyped call, C++
rejected it). `astdef.backendMintedDisamb` is now the single definition and all
three call it. `globalName` still reads `disamb` directly — correct for a loaded
symbol, and the round-trip invariant that makes it agree is now stated in the
shared function instead of left implicit.
Pure de-duplication, verified as such: all 219 generated `.c` files of a
219-module corpus and the linked binary are byte-identical to the previous
commit. Plus 16/16 metamorphic IC tests, the 17-file `koch ic` suite, 13/13
differential edit checks against `nim c`, and the debug and release `bootic`
fixed points.
Note for the record: this started as an attempt to replace the per-process
`_c<itemId.item>` counter with a content hash. Instrumenting both mangling
sites showed that branch is never taken — 0 of 166 backend-minted manglings on
the corpus, 0 of 257 on the compiler, all going through the content-derived
path — so rewriting the scheme would have shifted every backend-minted C name
and forced an `icFormatVersion` bump for no demonstrable benefit.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
fixes#24705
```nim
proc xxx(v: static int) =
echo v
xxx(10)
xxx(20)
```
They are mangled as `_ZN14titaniummangle7xxx_s10E` and
`_ZN14titaniummangle7xxx_s20E` with `--debugger:native`. Static
parameters are prefixed with `_s` to distinguish simple cases like
`xxx(10, 15)` and `xxx(101, 5)` if `xxx` supports two `static[int]`
parameters
the function name extension encoded by paths could be useful for
debugging where the function is from
Before:
```js
function newSeq_33556909(len_33556911)
```
After:
```js
function newSeq__system_u2477(len_p0)
```
* right shift is now by default sign preserving
* fix hashString and semfold
* enable arithmetic shift right globally for CI
* fix typo
* remove xxx
* use oldShiftRight as flag
* apply feedback
* add changelog entry
* Why is tyInferred needed?
The bindings in TCandidate are capable of inferring types within a single
call expression. In concepts, we need to infer types in the same way, but
across the whole body of the concept.
Previously, once a concept type param was inferred, it was destructively
mutated using t.assignType, but this proved to be problematic in the presence
of overloads, because the bindings established while a non-matching overload
is tested must be reverted/forgotten. tyInferred offers a non-destructive way to
keep track of the inference progress.
While introducing new types usually requires a lot of code paths in the compiler
to updated, currently tyInferred is only a short-lived type within the concept body
pass and it's unlikely to introduce breakage elsewhere in the compiler.
