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5d9fdab3de
we now keep not a table of all positions, but a table of all origins and their sizes. position indices are now direct pointers into the virtual concatenation of all parsed contents. this slightly reduces memory usage and time spent in the parser, at the cost of not being able to report positions if the total input size exceeds 4GiB. this limit is not unique to nix though, rustc and clang also limit their input to 4GiB (although at least clang refuses to process inputs that are larger, we will not). this new 4GiB limit probably will not cause any problems for quite a while, all of nixpkgs together is less than 100MiB in size and already needs over 700MiB of memory and multiple seconds just to parse. 4GiB worth of input will easily take multiple minutes and over 30GiB of memory without even evaluating anything. if problems *do* arise we can probably recover the old table-based system by adding some tracking to Pos::Origin (or increasing the size of PosIdx outright), but for time being this looks like more complexity than it's worth. since we now need to read the entire input again to determine the line/column of a position we'll make unsafeGetAttrPos slightly lazy: mostly the set it returns is only used to determine the file of origin of an attribute, not its exact location. the thunks do not add measurable runtime overhead. notably this change is necessary to allow changing the parser since apparently nothing supports nix's very idiosyncratic line ending choice of "anything goes", making it very hard to calculate line/column positions in the parser (while byte offsets are very easy).
56 lines
1.5 KiB
C++
56 lines
1.5 KiB
C++
#pragma once
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///@file
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#include "eval.hh"
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#include <tuple>
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#include <vector>
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namespace nix {
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/**
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* For functions where we do not expect deep recursion, we can use a sizable
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* part of the stack a free allocation space.
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*
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* Note: this is expected to be multiplied by sizeof(Value), or about 24 bytes.
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*/
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constexpr size_t nonRecursiveStackReservation = 128;
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/**
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* Functions that maybe applied to self-similar inputs, such as concatMap on a
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* tree, should reserve a smaller part of the stack for allocation.
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*
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* Note: this is expected to be multiplied by sizeof(Value), or about 24 bytes.
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*/
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constexpr size_t conservativeStackReservation = 16;
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struct RegisterPrimOp
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{
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typedef std::vector<PrimOp> PrimOps;
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static PrimOps * primOps;
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/**
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* You can register a constant by passing an arity of 0. fun
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* will get called during EvalState initialization, so there
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* may be primops not yet added and builtins is not yet sorted.
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*/
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RegisterPrimOp(PrimOp && primOp);
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};
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/* These primops are disabled without enableNativeCode, but plugins
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may wish to use them in limited contexts without globally enabling
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them. */
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/**
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* Load a ValueInitializer from a DSO and return whatever it initializes
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*/
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void prim_importNative(EvalState & state, const PosIdx pos, Value * * args, Value & v);
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/**
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* Execute a program and parse its output
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*/
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void prim_exec(EvalState & state, const PosIdx pos, Value * * args, Value & v);
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void makePositionThunks(EvalState & state, const PosIdx pos, Value & line, Value & column);
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}
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