nixos/nix
1
1
Fork 0
mirror of https://github.com/NixOS/nix.git synced 2025-11-19 08:49:35 +01:00
Code Activity

Add a “cached thunk” value type

Browse source
This commit is contained in:
regnat 2021-06-04 16:45:22 +02:00
parent 753730c410
commit fbaee9b8fb
3 changed files with 31 additions and 7 deletions
Download patch file Download diff file Expand all files Collapse all files

4
src/libexpr/eval-inline.hh
View file

@ -46,6 +46,10 @@ void EvalState::forceValue(Value & v, const Pos & pos)
}
else if (v.isApp())
callFunction(*v.app.left, *v.app.right, v, noPos);
else if (v.isCachedThunk()) {
v.mkThunk(v.cachedThunk.thunk->env, v.cachedThunk.thunk->expr);
forceValue(v, pos);
}
else if (v.isBlackhole())
throwEvalError(pos, "infinite recursion encountered");
}

9
src/libexpr/eval.cc
View file

@ -124,6 +124,7 @@ void printValue(std::ostream & str, std::set<const Value *> & active, const Valu
str << "]";
break;
case tThunk:
case tCachedThunk:
case tApp:
str << "<CODE>";
break;
@ -195,7 +196,7 @@ string showType(const Value & v)
case tPrimOpApp:
return fmt("the partially applied built-in function '%s'", string(getPrimOp(v)->primOp->name));
case tExternal: return v.external->showType();
case tThunk: return "a thunk";
case tThunk: case tCachedThunk: return "a thunk";
case tApp: return "a function application";
case tBlackhole: return "a black hole";
default:
@ -218,7 +219,7 @@ bool Value::isTrivial() const
return
internalType != tApp
&& internalType != tPrimOpApp
&& (internalType != tThunk
&& ((internalType != tThunk && internalType != tCachedThunk)
|| (dynamic_cast<ExprAttrs *>(thunk.expr)
&& ((ExprAttrs *) thunk.expr)->dynamicAttrs.empty())
|| dynamic_cast<ExprLambda *>(thunk.expr)
@ -1818,6 +1819,8 @@ ValueCache & Value::getEvalCache()
{
if (internalType == tAttrs) {
return attrs->eval_cache;
} else if (internalType == tCachedThunk) {
return *cachedThunk.cache;
} else {
return ValueCache::empty;
}
@ -1897,6 +1900,8 @@ void Value::setEvalCache(ValueCache & newCache)
{
if (internalType == tAttrs) {
attrs->eval_cache = newCache;
} else if (internalType == tCachedThunk) {
cachedThunk.cache = &newCache;
}
}

25
src/libexpr/value.hh
View file

@ -23,6 +23,7 @@ typedef enum {
tApp,
tLambda,
tBlackhole,
tCachedThunk,
tPrimOp,
tPrimOpApp,
tExternal,
@ -56,7 +57,6 @@ struct Pos;
class EvalState;
class XMLWriter;
class JSONPlaceholder;
class ValueCache;
@ -105,6 +105,10 @@ class ExternalValueBase
std::ostream & operator << (std::ostream & str, const ExternalValueBase & v);
struct Thunk {
Env * env;
Expr * expr;
};
struct Value
{
@ -124,6 +128,7 @@ public:
inline bool isThunk() const { return internalType == tThunk; };
inline bool isApp() const { return internalType == tApp; };
inline bool isBlackhole() const { return internalType == tBlackhole; };
inline bool isCachedThunk() const { return internalType == tCachedThunk; };
// type() == nFunction
inline bool isLambda() const { return internalType == tLambda; };
@ -167,10 +172,13 @@ public:
Value * * elems;
} bigList;
Value * smallList[2];
Thunk thunk;
struct {
Env * env;
Expr * expr;
} thunk;
Thunk * thunk;
// This is a pointer only to prevent a recursive import as
// `EvalCache` is already a pointer so would fit very nicely here.
ValueCache * cache;
} cachedThunk;
struct {
Value * left, * right;
} app;
@ -201,7 +209,7 @@ public:
case tLambda: case tPrimOp: case tPrimOpApp: return nFunction;
case tExternal: return nExternal;
case tFloat: return nFloat;
case tThunk: case tApp: case tBlackhole: return nThunk;
case tThunk: case tApp: case tBlackhole: case tCachedThunk: return nThunk;
}
abort();
}
@ -274,6 +282,13 @@ public:
thunk.expr = ex;
}
inline void mkCachedThunk(Thunk * t, ValueCache * cache)
{
internalType = tCachedThunk;
cachedThunk.thunk = t;
cachedThunk.cache = cache;
}
inline void mkApp(Value * l, Value * r)
{
internalType = tApp;