From 898c47384f651f51b3e4b63c271da274db8fca2e Mon Sep 17 00:00:00 2001 From: Robert Hensing Date: Thu, 16 Nov 2023 12:48:37 +0100 Subject: [PATCH] primops: Err on the side of less stack usage Try to stay away from stack overflows. These small vectors use stack space. Most instances will not need to allocate because in general most things are small, and large things are worth heap allocating. 16 * 3 * word = 384 bytes is still quite a bit, but these functions tend not to be part of deep recursions. --- src/libexpr/eval.cc | 2 +- src/libexpr/primops.cc | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc index bfbda52ef..2fcbf3311 100644 --- a/src/libexpr/eval.cc +++ b/src/libexpr/eval.cc @@ -2015,7 +2015,7 @@ void ExprConcatStrings::eval(EvalState & state, Env & env, Value & v) return result; }; - boost::container::small_vector values(es->size()); + boost::container::small_vector values(es->size()); Value * vTmpP = values.data(); for (auto & [i_pos, i] : *es) { diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc index d104b7180..7aa212281 100644 --- a/src/libexpr/primops.cc +++ b/src/libexpr/primops.cc @@ -2549,7 +2549,7 @@ static void prim_removeAttrs(EvalState & state, const PosIdx pos, Value * * args /* Get the attribute names to be removed. We keep them as Attrs instead of Symbols so std::set_difference can be used to remove them from attrs[0]. */ - boost::container::small_vector names; + boost::container::small_vector names; names.reserve(args[1]->listSize()); for (auto elem : args[1]->listItems()) { state.forceStringNoCtx(*elem, pos, "while evaluating the values of the second argument passed to builtins.removeAttrs"); @@ -3452,7 +3452,7 @@ static void prim_concatMap(EvalState & state, const PosIdx pos, Value * * args, state.forceList(*args[1], pos, "while evaluating the second argument passed to builtins.concatMap"); auto nrLists = args[1]->listSize(); - boost::container::small_vector lists(nrLists); + boost::container::small_vector lists(nrLists); size_t len = 0; for (unsigned int n = 0; n < nrLists; ++n) {