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libexpr: remove EvalState parse caches

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nothing needs these any more. the CLI calls evalFile, but only in places
where it'll only be called *once* per process lifetime. __import does so
too, but import doesn't care about the parse tree, only the eval result.

interestingly this improves eval performance by 6% on system eval unless
GC never occurs. no idea why this makes a GCing eval faster, but it does

Change-Id: I8289528550244e0a8b5ebc7284d8fb9aaac59e20
This commit is contained in:
eldritch horrors 2024-11-27 02:09:08 +01:00
parent f815b966c4
commit 66d7128512
2 changed files with 11 additions and 48 deletions
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43
lix/libexpr/eval.cc
View file

@ -941,51 +941,24 @@ void EvalState::evalFile(const SourcePath & path_, Value & v, bool mustBeTrivial
} }
debug("evaluating file '%1%'", resolvedPath); debug("evaluating file '%1%'", resolvedPath);
Expr * e = nullptr; Expr & e = parseExprFromFile(checkSourcePath(resolvedPath));
auto j = fileParseCache.find(resolvedPath);
if (j != fileParseCache.end())
e = j->second;
if (!e)
e = &parseExprFromFile(checkSourcePath(resolvedPath));
cacheFile(path, resolvedPath, e, v, mustBeTrivial);
}
void EvalState::resetFileCache()
{
fileEvalCache.clear();
fileParseCache.clear();
}
void EvalState::cacheFile(
const SourcePath & path,
const SourcePath & resolvedPath,
Expr * e,
Value & v,
bool mustBeTrivial)
{
fileParseCache[resolvedPath] = e;
try { try {
auto dts = debug auto dts = debug
? makeDebugTraceStacker( ? makeDebugTraceStacker(
*this, *this,
*e, e,
this->baseEnv, this->baseEnv,
e->getPos() ? std::make_shared<Pos>(positions[e->getPos()]) : nullptr, e.getPos() ? std::make_shared<Pos>(positions[e.getPos()]) : nullptr,
"while evaluating the file '%1%':", resolvedPath.to_string()) "while evaluating the file '%1%':", resolvedPath.to_string())
: nullptr; : nullptr;
// Enforce that 'flake.nix' is a direct attrset, not a // Enforce that 'flake.nix' is a direct attrset, not a
// computation. // computation.
if (mustBeTrivial && if (mustBeTrivial &&
!(dynamic_cast<ExprAttrs *>(e))) !(dynamic_cast<ExprAttrs *>(&e)))
error<EvalError>("file '%s' must be an attribute set", path).debugThrow(); error<EvalError>("file '%s' must be an attribute set", path).debugThrow();
eval(*e, v); eval(e, v);
} catch (Error & e) { } catch (Error & e) {
addErrorTrace(e, "while evaluating the file '%1%':", resolvedPath.to_string()); addErrorTrace(e, "while evaluating the file '%1%':", resolvedPath.to_string());
throw; throw;
@ -996,6 +969,12 @@ void EvalState::cacheFile(
} }
void EvalState::resetFileCache()
{
fileEvalCache.clear();
}
void EvalState::eval(Expr & e, Value & v) void EvalState::eval(Expr & e, Value & v)
{ {
e.eval(*this, baseEnv, v); e.eval(*this, baseEnv, v);

16
lix/libexpr/eval.hh
View file

@ -327,12 +327,6 @@ private:
paths. */ paths. */
std::map<SourcePath, StorePath> srcToStore; std::map<SourcePath, StorePath> srcToStore;
/**
* A cache from path names to parse trees.
*/
using FileParseCache = GcMap<SourcePath, Expr *>;
FileParseCache fileParseCache;
/** /**
* A cache from path names to values. * A cache from path names to values.
*/ */
@ -426,16 +420,6 @@ public:
*/ */
void evalFile(const SourcePath & path, Value & v, bool mustBeTrivial = false); void evalFile(const SourcePath & path, Value & v, bool mustBeTrivial = false);
/**
* Like `evalFile`, but with an already parsed expression.
*/
void cacheFile(
const SourcePath & path,
const SourcePath & resolvedPath,
Expr * e,
Value & v,
bool mustBeTrivial = false);
void resetFileCache(); void resetFileCache();
/** /**