* Don't use dynamic_cast, it's very slow. "nix-instantiate
/etc/nixos/nixos -A system" spent about 10% of its time in dynamic_cast.
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adaf64a99b
commit
35f2a6ba82
3 changed files with 23 additions and 24 deletions
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@ -404,31 +404,30 @@ void EvalState::mkThunk_(Value & v, Expr * expr)
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}
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unsigned long nrAvoided = 0;
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/* Create a thunk for the delayed computation of the given expression
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in the given environment. But if the expression is a variable,
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then look it up right away. This significantly reduces the number
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of thunks allocated. */
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Value * EvalState::maybeThunk(Env & env, Expr * expr)
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Value * Expr::maybeThunk(EvalState & state, Env & env)
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{
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ExprVar * var;
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/* Ignore variables from `withs' because they can throw an
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exception. */
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if ((var = dynamic_cast<ExprVar *>(expr))) {
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Value * v = lookupVar(&env, var->info);
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/* The value might not be initialised in the environment yet.
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In that case, ignore it. */
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if (v) { nrAvoided++; return v; }
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}
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Value * v = allocValue();
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mkThunk(*v, env, expr);
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Value * v = state.allocValue();
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mkThunk(*v, env, this);
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return v;
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}
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unsigned long nrAvoided = 0;
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Value * ExprVar::maybeThunk(EvalState & state, Env & env)
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{
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Value * v = state.lookupVar(&env, info);
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/* The value might not be initialised in the environment yet.
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In that case, ignore it. */
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if (v) { nrAvoided++; return v; }
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return Expr::maybeThunk(state, env);
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}
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void EvalState::evalFile(const Path & path, Value & v)
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{
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FileEvalCache::iterator i = fileEvalCache.find(path);
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@ -560,7 +559,7 @@ void ExprAttrs::eval(EvalState & state, Env & env, Value & v)
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vAttr = state.allocValue();
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mkThunk(*vAttr, env2, i->second.e);
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} else
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vAttr = state.maybeThunk(env2, i->second.e);
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vAttr = i->second.e->maybeThunk(state, env2);
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env2.values[displ++] = vAttr;
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v.attrs->push_back(Attr(i->first, vAttr, &i->second.pos));
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}
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@ -593,7 +592,7 @@ void ExprAttrs::eval(EvalState & state, Env & env, Value & v)
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if (i->second.inherited)
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v.attrs->push_back(Attr(i->first, state.lookupVar(&env, i->second.var), &i->second.pos));
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else
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v.attrs->push_back(Attr(i->first, state.maybeThunk(env, i->second.e), &i->second.pos));
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v.attrs->push_back(Attr(i->first, i->second.e->maybeThunk(state, env), &i->second.pos));
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}
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}
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@ -613,7 +612,7 @@ void ExprLet::eval(EvalState & state, Env & env, Value & v)
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if (i->second.inherited)
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env2.values[displ++] = state.lookupVar(&env, i->second.var);
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else
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env2.values[displ++] = state.maybeThunk(env2, i->second.e);
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env2.values[displ++] = i->second.e->maybeThunk(state, env2);
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state.eval(env2, body, v);
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}
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@ -623,7 +622,7 @@ void ExprList::eval(EvalState & state, Env & env, Value & v)
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{
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state.mkList(v, elems.size());
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for (unsigned int n = 0; n < v.list.length; ++n)
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v.list.elems[n] = state.maybeThunk(env, elems[n]);
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v.list.elems[n] = elems[n]->maybeThunk(state, env);
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}
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@ -716,7 +715,7 @@ void ExprApp::eval(EvalState & state, Env & env, Value & v)
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{
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Value vFun;
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state.eval(env, e1, vFun);
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state.callFunction(vFun, *state.maybeThunk(env, e2), v);
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state.callFunction(vFun, *(e2->maybeThunk(state, env)), v);
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}
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@ -791,7 +790,7 @@ void EvalState::callFunction(Value & fun, Value & arg, Value & v)
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if (j == arg.attrs->end()) {
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if (!i->def) throwTypeError("function at %1% called without required argument `%2%'",
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fun.lambda.fun->pos, i->name);
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env2.values[displ++] = maybeThunk(env2, i->def);
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env2.values[displ++] = i->def->maybeThunk(*this, env2);
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} else {
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attrsUsed++;
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env2.values[displ++] = j->value;
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@ -346,8 +346,6 @@ public:
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void mkAttrs(Value & v, unsigned int expected);
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void mkThunk_(Value & v, Expr * expr);
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Value * maybeThunk(Env & env, Expr * expr);
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/* Print statistics. */
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void printStats();
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@ -53,6 +53,7 @@ struct Expr
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virtual void show(std::ostream & str);
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virtual void bindVars(const StaticEnv & env);
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virtual void eval(EvalState & state, Env & env, Value & v);
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virtual Value * maybeThunk(EvalState & state, Env & env);
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};
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std::ostream & operator << (std::ostream & str, Expr & e);
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@ -117,6 +118,7 @@ struct ExprVar : Expr
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VarRef info;
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ExprVar(const Symbol & name) : info(name) { };
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COMMON_METHODS
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Value * maybeThunk(EvalState & state, Env & env);
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};
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struct ExprSelect : Expr
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