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* In eval(), don't use the target value `v' as a temporary.

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Overwriting `v' breaks when the expression evaluation to an
  assertion failure or throw.
This commit is contained in:
Eelco Dolstra 2010-04-06 14:15:29 +00:00
parent a5ece7d016
commit a353aef0b1
1 changed files with 17 additions and 13 deletions
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30
src/libexpr/eval.cc
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@ -369,10 +369,11 @@ void EvalState::eval(Env & env, Expr e, Value & v)
}
else if (matchSelect(e, e2, name)) {
eval(env, e2, v);
forceAttrs(v); // !!! eval followed by force is slightly inefficient
Bindings::iterator i = v.attrs->find(name);
if (i == v.attrs->end())
Value v2;
eval(env, e2, v2);
forceAttrs(v2); // !!! eval followed by force is slightly inefficient
Bindings::iterator i = v2.attrs->find(name);
if (i == v2.attrs->end())
throwEvalError("attribute `%1%' missing", aterm2String(name));
try {
forceValue(i->second);
@ -391,10 +392,11 @@ void EvalState::eval(Env & env, Expr e, Value & v)
}
else if (matchCall(e, fun, arg)) {
eval(env, fun, v);
Value vFun;
eval(env, fun, vFun);
Value vArg;
mkThunk(vArg, env, arg); // !!! should this be on the heap?
callFunction(v, vArg, v);
callFunction(vFun, vArg, v);
}
else if (matchWith(e, attrs, body, pos)) {
@ -446,9 +448,10 @@ void EvalState::eval(Env & env, Expr e, Value & v)
std::ostringstream s;
bool first = true, isPath = false;
Value vStr;
for (ATermIterator i(es); i; ++i) {
eval(env, *i, v);
eval(env, *i, vStr);
/* If the first element is a path, then the result will
also be a path, we don't copy anything (yet - that's
@ -456,11 +459,11 @@ void EvalState::eval(Env & env, Expr e, Value & v)
in a derivation), and none of the strings are allowed
to have contexts. */
if (first) {
isPath = v.type == tPath;
isPath = vStr.type == tPath;
first = false;
}
s << coerceToString(v, context, false, !isPath);
s << coerceToString(vStr, context, false, !isPath);
}
if (isPath && !context.empty())
@ -514,9 +517,10 @@ void EvalState::eval(Env & env, Expr e, Value & v)
/* Attribute existence test (?). */
else if (matchOpHasAttr(e, e1, name)) {
eval(env, e1, v);
forceAttrs(v);
mkBool(v, v.attrs->find(name) != v.attrs->end());
Value vAttrs;
eval(env, e1, vAttrs);
forceAttrs(vAttrs);
mkBool(v, vAttrs.attrs->find(name) != vAttrs.attrs->end());
}
else throw Error("unsupported term");
@ -660,7 +664,7 @@ void EvalState::strictEval(Expr e, Value & v)
void EvalState::forceValue(Value & v)
{
if (v.type == tThunk) {
v.type = tBlackhole;
//v.type = tBlackhole;
eval(*v.thunk.env, v.thunk.expr, v);
}
else if (v.type == tCopy) {