* Don't create thunks for simple constants (integers, strings, paths)

and allocate them only once.
* Move Value and related functions into value.hh.
This commit is contained in:
Eelco Dolstra 2012-01-07 17:26:33 +00:00
parent d4e6b9f2d6
commit 9fe24c5a0d
5 changed files with 193 additions and 133 deletions

View File

@ -8,7 +8,7 @@ libexpr_la_SOURCES = \
pkginclude_HEADERS = \
nixexpr.hh eval.hh lexer-tab.hh parser-tab.hh \
get-drvs.hh attr-path.hh value-to-xml.hh common-opts.hh \
names.hh symbol-table.hh
names.hh symbol-table.hh value.hh
libexpr_la_LIBADD = ../libutil/libutil.la ../libstore/libstore.la \
../boost/format/libformat.la @BDW_GC_LIBS@

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@ -283,9 +283,7 @@ LocalNoInline(void addErrorPrefix(Error & e, const char * s, const string & s2,
void mkString(Value & v, const char * s)
{
v.type = tString;
v.string.s = GC_STRDUP(s);
v.string.context = 0;
mkStringNoCopy(v, GC_STRDUP(s));
}
@ -303,19 +301,9 @@ void mkString(Value & v, const string & s, const PathSet & context)
}
void mkString(Value & v, const Symbol & s)
{
v.type = tString;
v.string.s = ((string) s).c_str();
v.string.context = 0;
}
void mkPath(Value & v, const char * s)
{
clearValue(v);
v.type = tPath;
v.path = GC_STRDUP(s);
mkPathNoCopy(v, GC_STRDUP(s));
}
@ -426,6 +414,26 @@ Value * ExprVar::maybeThunk(EvalState & state, Env & env)
}
Value * ExprString::maybeThunk(EvalState & state, Env & env)
{
nrAvoided++;
return &v;
}
Value * ExprInt::maybeThunk(EvalState & state, Env & env)
{
nrAvoided++;
return &v;
}
Value * ExprPath::maybeThunk(EvalState & state, Env & env)
{
nrAvoided++;
return &v;
}
void EvalState::evalFile(const Path & path, Value & v)
{
FileEvalCache::iterator i = fileEvalCache.find(path);
@ -512,19 +520,19 @@ void Expr::eval(EvalState & state, Env & env, Value & v)
void ExprInt::eval(EvalState & state, Env & env, Value & v)
{
mkInt(v, n);
v = this->v;
}
void ExprString::eval(EvalState & state, Env & env, Value & v)
{
mkString(v, s);
v = this->v;
}
void ExprPath::eval(EvalState & state, Env & env, Value & v)
{
mkPath(v, s.c_str());
v = this->v;
}

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@ -1,6 +1,7 @@
#ifndef __EVAL_H
#define __EVAL_H
#include "value.hh"
#include "nixexpr.hh"
#include "symbol-table.hh"
#include "hash.hh"
@ -16,8 +17,6 @@ namespace nix {
class EvalState;
struct Env;
struct Value;
struct Attr;
@ -38,23 +37,6 @@ public:
};
typedef enum {
tInt = 1,
tBool,
tString,
tPath,
tNull,
tAttrs,
tList,
tThunk,
tApp,
tLambda,
tBlackhole,
tPrimOp,
tPrimOpApp,
} ValueType;
typedef void (* PrimOpFun) (EvalState & state, Value * * args, Value & v);
@ -68,64 +50,6 @@ struct PrimOp
};
struct Value
{
ValueType type;
union
{
int integer;
bool boolean;
/* Strings in the evaluator carry a so-called `context' (the
ATermList) which is a list of strings representing store
paths. This is to allow users to write things like
"--with-freetype2-library=" + freetype + "/lib"
where `freetype' is a derivation (or a source to be copied
to the store). If we just concatenated the strings without
keeping track of the referenced store paths, then if the
string is used as a derivation attribute, the derivation
will not have the correct dependencies in its inputDrvs and
inputSrcs.
The semantics of the context is as follows: when a string
with context C is used as a derivation attribute, then the
derivations in C will be added to the inputDrvs of the
derivation, and the other store paths in C will be added to
the inputSrcs of the derivations.
For canonicity, the store paths should be in sorted order. */
struct {
const char * s;
const char * * context; // must be in sorted order
} string;
const char * path;
Bindings * attrs;
struct {
unsigned int length;
Value * * elems;
} list;
struct {
Env * env;
Expr * expr;
} thunk;
struct {
Value * left, * right;
} app;
struct {
Env * env;
ExprLambda * fun;
} lambda;
PrimOp * primOp;
struct {
Value * left, * right;
} primOpApp;
};
};
struct Env
{
Env * up;
@ -149,41 +73,7 @@ struct Attr
};
/* After overwriting an app node, be sure to clear pointers in the
Value to ensure that the target isn't kept alive unnecessarily. */
static inline void clearValue(Value & v)
{
v.app.right = 0;
}
static inline void mkInt(Value & v, int n)
{
clearValue(v);
v.type = tInt;
v.integer = n;
}
static inline void mkBool(Value & v, bool b)
{
clearValue(v);
v.type = tBool;
v.boolean = b;
}
static inline void mkApp(Value & v, Value & left, Value & right)
{
v.type = tApp;
v.app.left = &left;
v.app.right = &right;
}
void mkString(Value & v, const char * s);
void mkString(Value & v, const string & s, const PathSet & context = PathSet());
void mkPath(Value & v, const char * s);
void copyContext(const Value & v, PathSet & context);

View File

@ -1,6 +1,7 @@
#ifndef __NIXEXPR_H
#define __NIXEXPR_H
#include "value.hh"
#include "symbol-table.hh"
#include <map>
@ -66,15 +67,19 @@ std::ostream & operator << (std::ostream & str, Expr & e);
struct ExprInt : Expr
{
int n;
ExprInt(int n) : n(n) { };
Value v;
ExprInt(int n) : n(n) { mkInt(v, n); };
COMMON_METHODS
Value * maybeThunk(EvalState & state, Env & env);
};
struct ExprString : Expr
{
Symbol s;
ExprString(const Symbol & s) : s(s) { };
Value v;
ExprString(const Symbol & s) : s(s) { mkString(v, s); };
COMMON_METHODS
Value * maybeThunk(EvalState & state, Env & env);
};
/* Temporary class used during parsing of indented strings. */
@ -87,8 +92,10 @@ struct ExprIndStr : Expr
struct ExprPath : Expr
{
string s;
ExprPath(const string & s) : s(s) { };
Value v;
ExprPath(const string & s) : s(s) { mkPathNoCopy(v, this->s.c_str()); };
COMMON_METHODS
Value * maybeThunk(EvalState & state, Env & env);
};
struct VarRef

155
src/libexpr/value.hh Normal file
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@ -0,0 +1,155 @@
#ifndef __VALUE_H
#define __VALUE_H
#include "symbol-table.hh"
namespace nix {
typedef enum {
tInt = 1,
tBool,
tString,
tPath,
tNull,
tAttrs,
tList,
tThunk,
tApp,
tLambda,
tBlackhole,
tPrimOp,
tPrimOpApp,
} ValueType;
struct Bindings;
struct Env;
struct Expr;
struct ExprLambda;
struct PrimOp;
struct PrimOp;
struct Symbol;
struct Value
{
ValueType type;
union
{
int integer;
bool boolean;
/* Strings in the evaluator carry a so-called `context' (the
ATermList) which is a list of strings representing store
paths. This is to allow users to write things like
"--with-freetype2-library=" + freetype + "/lib"
where `freetype' is a derivation (or a source to be copied
to the store). If we just concatenated the strings without
keeping track of the referenced store paths, then if the
string is used as a derivation attribute, the derivation
will not have the correct dependencies in its inputDrvs and
inputSrcs.
The semantics of the context is as follows: when a string
with context C is used as a derivation attribute, then the
derivations in C will be added to the inputDrvs of the
derivation, and the other store paths in C will be added to
the inputSrcs of the derivations.
For canonicity, the store paths should be in sorted order. */
struct {
const char * s;
const char * * context; // must be in sorted order
} string;
const char * path;
Bindings * attrs;
struct {
unsigned int length;
Value * * elems;
} list;
struct {
Env * env;
Expr * expr;
} thunk;
struct {
Value * left, * right;
} app;
struct {
Env * env;
ExprLambda * fun;
} lambda;
PrimOp * primOp;
struct {
Value * left, * right;
} primOpApp;
};
};
/* After overwriting an app node, be sure to clear pointers in the
Value to ensure that the target isn't kept alive unnecessarily. */
static inline void clearValue(Value & v)
{
v.app.right = 0;
}
static inline void mkInt(Value & v, int n)
{
clearValue(v);
v.type = tInt;
v.integer = n;
}
static inline void mkBool(Value & v, bool b)
{
clearValue(v);
v.type = tBool;
v.boolean = b;
}
static inline void mkApp(Value & v, Value & left, Value & right)
{
v.type = tApp;
v.app.left = &left;
v.app.right = &right;
}
static inline void mkStringNoCopy(Value & v, const char * s)
{
v.type = tString;
v.string.s = s;
v.string.context = 0;
}
static inline void mkString(Value & v, const Symbol & s)
{
mkStringNoCopy(v, ((string) s).c_str());
}
void mkString(Value & v, const char * s);
static inline void mkPathNoCopy(Value & v, const char * s)
{
clearValue(v);
v.type = tPath;
v.path = s;
}
void mkPath(Value & v, const char * s);
}
#endif /* !__VALUE_H */