lix/src/libexpr/eval-inline.hh
Qyriad a3361557e3 libexpr: refactor gc-agnostic helpers into one place
Change-Id: Icc4b367e4f670d47256f62a3a002cd248a5c2d3b
2024-07-20 20:20:01 +00:00

126 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 (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 = (Env *) p;
} else
#endif
env = (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();
}
}
}