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Allocate LazyBinOp values separately from Value
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So as to not increase the sizeof(Value) from 24 bytes to 40 bytes
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@infinisil
infinisil committed Oct 21, 2020
1 parent 5b1ef7b commit 152048d
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Showing 4 changed files with 59 additions and 44 deletions.
14 changes: 4 additions & 10 deletions src/libexpr/eval-inline.hh
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Original file line number Diff line number Diff line change
Expand Up @@ -47,20 +47,14 @@ void EvalState::forceValue(Value & v, const Pos & pos)
}
}
else if (v.type == tLazyBinOp) {
Env * env = v.lazyBinOp.env;
ExprLazyBinOp * expr = v.lazyBinOp.expr;
Value * left = v.lazyBinOp.left;
Value * right = v.lazyBinOp.right;
Value::LazyBinOp * lazyBinOp = v.lazyBinOp;
try {
v.type = tBlackhole;
//checkInterrupt();
expr->evalLazyBinOp(*this, *env, v);
lazyBinOp->expr->evalLazyBinOp(*this, *lazyBinOp->env, v);
} catch (...) {
v.type = tLazyBinOp;
v.lazyBinOp.env = env;
v.lazyBinOp.expr = expr;
v.lazyBinOp.left = left;
v.lazyBinOp.right = right;
v.lazyBinOp = lazyBinOp;
throw;
}
}
Expand All @@ -78,7 +72,7 @@ Attr * EvalState::evalValueAttr(Value & v, const Symbol & name, const Pos & pos)
return v.thunk.expr->evalAttr(*this, *v.thunk.env, v, name);
}
else if (v.type == tLazyBinOp) {
return v.lazyBinOp.expr->evalLazyBinOpAttr(*this, *v.lazyBinOp.env, v, name);
return v.lazyBinOp->expr->evalLazyBinOpAttr(*this, *v.lazyBinOp->env, v, name);
}
else if (v.type == tApp) {
return callFunctionAttr(*v.app.left, *v.app.right, v, name, pos);
Expand Down
71 changes: 43 additions & 28 deletions src/libexpr/eval.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -750,6 +750,12 @@ Value * EvalState::allocValue()
return v;
}

Value::LazyBinOp * EvalState::allocLazyBinOpValue()
{
nrLazyBinOpValues++;
auto v = (Value::LazyBinOp *) allocBytes(sizeof(Value::LazyBinOp));
return v;
}

Env & EvalState::allocEnv(size_t size)
{
Expand Down Expand Up @@ -1836,17 +1842,17 @@ void ExprOpUpdate::updateAttrs(EvalState & state, const Value & v1, const Value
void ExprOpUpdate::evalLazyBinOp(EvalState & state, Env & env, Value & v)
{
Value v1;
if (v.type == tLazyBinOp && v.lazyBinOp.left) {
state.forceAttrs(*v.lazyBinOp.left);
v1 = *v.lazyBinOp.left;
if (v.type == tLazyBinOp && v.lazyBinOp->left) {
state.forceAttrs(*v.lazyBinOp->left);
v1 = *v.lazyBinOp->left;
} else {
state.evalAttrs(env, e1, v1);
}

Value v2;
if (v.type == tLazyBinOp && v.lazyBinOp.right) {
state.forceAttrs(*v.lazyBinOp.right);
v2 = *v.lazyBinOp.right;
if (v.type == tLazyBinOp && v.lazyBinOp->right) {
state.forceAttrs(*v.lazyBinOp->right);
v2 = *v.lazyBinOp->right;
} else {
state.evalAttrs(env, e2, v2);
}
Expand All @@ -1864,11 +1870,12 @@ Attr * ExprOpUpdate::evalLazyBinOpAttr(EvalState & state, Env & env, Value & v,
Attr * onRight = e2->evalAttr(state, env, v2, name);
if (onRight) {
v.type = tLazyBinOp;
v.lazyBinOp.expr = this;
v.lazyBinOp.env = &env;
v.lazyBinOp.left = nullptr;
v.lazyBinOp.right = state.allocValue();
*v.lazyBinOp.right = v2;
v.lazyBinOp = state.allocLazyBinOpValue();
v.lazyBinOp->expr = this;
v.lazyBinOp->env = &env;
v.lazyBinOp->left = nullptr;
v.lazyBinOp->right = state.allocValue();
*v.lazyBinOp->right = v2;
return onRight;
} else {
Value v1;
Expand All @@ -1878,39 +1885,40 @@ Attr * ExprOpUpdate::evalLazyBinOpAttr(EvalState & state, Env & env, Value & v,
return onLeft;
} else {
v.type = tLazyBinOp;
v.lazyBinOp.expr = this;
v.lazyBinOp.env = &env;
v.lazyBinOp.left = state.allocValue();
*v.lazyBinOp.left = v1;
v.lazyBinOp.right = state.allocValue();
*v.lazyBinOp.right = v2;
v.lazyBinOp = state.allocLazyBinOpValue();
v.lazyBinOp->expr = this;
v.lazyBinOp->env = &env;
v.lazyBinOp->left = state.allocValue();
*v.lazyBinOp->left = v1;
v.lazyBinOp->right = state.allocValue();
*v.lazyBinOp->right = v2;
return onLeft;
}
}
} else {
// We know that v.type == tLazyBinOp and that v.lazyBinOp.right != nullptr because that's all the above case can return

Attr * onRight = state.evalValueAttr(*v.lazyBinOp.right, name, pos);
Attr * onRight = state.evalValueAttr(*v.lazyBinOp->right, name, pos);
if (onRight) {
if (v.lazyBinOp.right->type == tAttrs && v.lazyBinOp.left && v.lazyBinOp.left->type == tAttrs) {
updateAttrs(state, *v.lazyBinOp.left, *v.lazyBinOp.right, v);
if (v.lazyBinOp->right->type == tAttrs && v.lazyBinOp->left && v.lazyBinOp->left->type == tAttrs) {
updateAttrs(state, *v.lazyBinOp->left, *v.lazyBinOp->right, v);
}
return onRight;
} else {
if (v.lazyBinOp.left) {
Attr * onLeft = state.evalValueAttr(*v.lazyBinOp.left, name, pos);
if (v.lazyBinOp.right->type == tAttrs && v.lazyBinOp.left->type == tAttrs) {
updateAttrs(state, *v.lazyBinOp.left, *v.lazyBinOp.right, v);
if (v.lazyBinOp->left) {
Attr * onLeft = state.evalValueAttr(*v.lazyBinOp->left, name, pos);
if (v.lazyBinOp->right->type == tAttrs && v.lazyBinOp->left->type == tAttrs) {
updateAttrs(state, *v.lazyBinOp->left, *v.lazyBinOp->right, v);
}
return onLeft;
} else {
Value v1;
Attr * onLeft = e1->evalAttr(state, env, v1, name);
if (v1.type == tAttrs && v.lazyBinOp.right->type == tAttrs) {
updateAttrs(state, v1, *v.lazyBinOp.right, v);
if (v1.type == tAttrs && v.lazyBinOp->right->type == tAttrs) {
updateAttrs(state, v1, *v.lazyBinOp->right, v);
} else {
v.lazyBinOp.left = state.allocValue();
*v.lazyBinOp.left = v1;
v.lazyBinOp->left = state.allocValue();
*v.lazyBinOp->left = v1;
}
return onLeft;
}
Expand Down Expand Up @@ -2386,6 +2394,7 @@ void EvalState::printStats()
uint64_t bEnvs = nrEnvs * sizeof(Env) + nrValuesInEnvs * sizeof(Value *);
uint64_t bLists = nrListElems * sizeof(Value *);
uint64_t bValues = nrValues * sizeof(Value);
uint64_t bLazyBinOpValues = nrLazyBinOpValues * sizeof(Value::LazyBinOp);
uint64_t bAttrsets = nrAttrsets * sizeof(Bindings) + nrAttrsInAttrsets * sizeof(Attr);

#if HAVE_BOEHMGC
Expand Down Expand Up @@ -2416,6 +2425,11 @@ void EvalState::printStats()
values.attr("number", nrValues);
values.attr("bytes", bValues);
}
{
auto lazyBinOpValues = topObj.object("lazyBinOpValues");
lazyBinOpValues.attr("number", nrLazyBinOpValues);
lazyBinOpValues.attr("bytes", bLazyBinOpValues);
}
{
auto syms = topObj.object("symbols");
syms.attr("number", symbols.size());
Expand All @@ -2431,6 +2445,7 @@ void EvalState::printStats()
auto sizes = topObj.object("sizes");
sizes.attr("Env", sizeof(Env));
sizes.attr("Value", sizeof(Value));
sizes.attr("Value::LazyBinOp", sizeof(Value::LazyBinOp));
sizes.attr("Bindings", sizeof(Bindings));
sizes.attr("Attr", sizeof(Attr));
}
Expand Down
2 changes: 2 additions & 0 deletions src/libexpr/eval.hh
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Original file line number Diff line number Diff line change
Expand Up @@ -295,6 +295,7 @@ public:

/* Allocation primitives. */
Value * allocValue();
Value::LazyBinOp * allocLazyBinOpValue();
Env & allocEnv(size_t size);

Value * allocAttr(Value & vAttrs, const Symbol & name);
Expand All @@ -319,6 +320,7 @@ private:
unsigned long nrEnvs = 0;
unsigned long nrValuesInEnvs = 0;
unsigned long nrValues = 0;
unsigned long nrLazyBinOpValues = 0;
unsigned long nrListElems = 0;
unsigned long nrAttrsets = 0;
unsigned long nrAttrsInAttrsets = 0;
Expand Down
16 changes: 10 additions & 6 deletions src/libexpr/value.hh
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Original file line number Diff line number Diff line change
Expand Up @@ -92,6 +92,15 @@ std::ostream & operator << (std::ostream & str, const ExternalValueBase & v);

struct Value
{

// Stored separately from Value as to not increase sizeof(Value)
struct LazyBinOp {
Env * env;
ExprLazyBinOp * expr;
Value * left;
Value * right;
};

ValueType type;
union
{
Expand Down Expand Up @@ -134,12 +143,7 @@ struct Value
Env * env;
Expr * expr;
} thunk;
struct {
Env * env;
ExprLazyBinOp * expr;
Value * left;
Value * right;
} lazyBinOp;
LazyBinOp * lazyBinOp;
struct {
Value * left, * right;
} app;
Expand Down

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