Files
lix/src/libexpr/eval-inline.hh
T
Jade LovelaceandRebecca Turner 0cc285f87b treewide: fix a bunch of lints
Fixes:
- Identifiers starting with _ are prohibited
- Some driveby header dependency cleaning which wound up with doing some
  extra fixups.
- Fucking C style casts, man. C++ made these 1000% worse by letting you
  also do memory corruption with them with references.
  - Remove casts to Expr * where ExprBlackHole is an incomplete type by
    introducing an explicitly-cast eBlackHoleAddr as Expr *.
  - An incredibly illegal cast of the text bytes of the StorePath hash
    into a size_t directly. You can't DO THAT.

    Replaced with actually parsing the hash so we get 100% of the bits
    being entropy, then memcpying the start of the hash. If this shows
    up in a profile we should just make the hash parser faster with a
    lookup table or something sensible like that.
  - This horrendous bit of UB which I thankfully slapped a deprecation
    warning on, built, and it didn't trigger anywhere so it was dead
    code and I just deleted it. But holy crap you *cannot* do that.

    inline void mkString(const Symbol & s)
    {
        mkString(((const std::string &) s).c_str());
    }
- Some wrong lints. Lots of wrong macro lints, one wrong
  suspicious-sizeof lint triggered by the template being instantiated
  with only pointers, but the calculation being correct for both
  pointers and not-pointers.
- Exceptions in destructors strike again. I tried to catch the
  exceptions that might actually happen rather than all the exceptions
  imaginable. We can let the runtime hard-kill it on other exceptions
  imo.

Change-Id: I71761620846cba64d66ee7ca231b20c061e69710
2024-08-26 16:13:03 -07:00

127 lines
3.3 KiB
C++

#pragma once
///@file
#include "print.hh"
#include "eval.hh"
#include "eval-error.hh"
#include "gc-alloc.hh"
namespace nix {
[[gnu::always_inline]]
Value * EvalState::allocValue()
{
#if HAVE_BOEHMGC
/* We use the boehm batch allocator to speed up allocations of Values (of which there are many).
GC_malloc_many returns a linked list of objects of the given size, where the first word
of each object is also the pointer to the next object in the list. This also means that we
have to explicitly clear the first word of every object we take. */
if (!*valueAllocCache) {
*valueAllocCache = GC_malloc_many(sizeof(Value));
if (!*valueAllocCache) throw std::bad_alloc();
}
/* GC_NEXT is a convenience macro for accessing the first word of an object.
Take the first list item, advance the list to the next item, and clear the next pointer. */
void * p = *valueAllocCache;
*valueAllocCache = GC_NEXT(p);
GC_NEXT(p) = nullptr;
#else
void * p = gcAllocBytes(sizeof(Value));
#endif
nrValues++;
return static_cast<Value *>(p);
}
[[gnu::always_inline]]
Env & EvalState::allocEnv(size_t size)
{
nrEnvs++;
nrValuesInEnvs += size;
Env * env;
#if HAVE_BOEHMGC
if (size == 1) {
/* see allocValue for explanations. */
if (!*env1AllocCache) {
*env1AllocCache = GC_malloc_many(sizeof(Env) + sizeof(Value *));
if (!*env1AllocCache) throw std::bad_alloc();
}
void * p = *env1AllocCache;
*env1AllocCache = GC_NEXT(p);
GC_NEXT(p) = nullptr;
env = static_cast<Env *>(p);
} else
#endif
env = static_cast<Env *>(gcAllocBytes(sizeof(Env) + size * sizeof(Value *)));
/* We assume that env->values has been cleared by the allocator; maybeThunk() and lookupVar fromWith expect this. */
return *env;
}
[[gnu::always_inline]]
void EvalState::forceValue(Value & v, const PosIdx pos)
{
if (v.isThunk()) {
Env * env = v.thunk.env;
Expr & expr = *v.thunk.expr;
try {
v.mkBlackhole();
//checkInterrupt();
expr.eval(*this, *env, v);
} catch (...) {
v.mkThunk(env, expr);
tryFixupBlackHolePos(v, pos);
throw;
}
}
else if (v.isApp())
callFunction(*v.app.left, *v.app.right, v, pos);
}
[[gnu::always_inline]]
inline void EvalState::forceAttrs(Value & v, const PosIdx pos, std::string_view errorCtx)
{
forceAttrs(v, [&]() { return pos; }, errorCtx);
}
template <typename Callable>
[[gnu::always_inline]]
inline void EvalState::forceAttrs(Value & v, Callable getPos, std::string_view errorCtx)
{
PosIdx pos = getPos();
forceValue(v, pos);
if (v.type() != nAttrs) {
error<TypeError>(
"expected a set but found %1%: %2%",
showType(v),
ValuePrinter(*this, v, errorPrintOptions)
).withTrace(pos, errorCtx).debugThrow();
}
}
[[gnu::always_inline]]
inline void EvalState::forceList(Value & v, const PosIdx pos, std::string_view errorCtx)
{
forceValue(v, pos);
if (!v.isList()) {
error<TypeError>(
"expected a list but found %1%: %2%",
showType(v),
ValuePrinter(*this, v, errorPrintOptions)
).withTrace(pos, errorCtx).debugThrow();
}
}
}