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Make ifs and asserts tail-recursive

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The local Value object prevented g++ from making a tail call.  Not
clear why.  In any case, not using a temporary makes g++ do the tail
call.
This commit is contained in:
Eelco Dolstra 2013-11-07 14:33:35 +01:00
parent 4badd7ed17
commit 273322c773
2 changed files with 11 additions and 4 deletions
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14
src/libexpr/eval.cc
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@ -480,9 +480,8 @@ void EvalState::eval(Expr * e, Value & v)
} }
inline bool EvalState::evalBool(Env & env, Expr * e) inline bool EvalState::evalBool(Env & env, Expr * e, Value & v)
{ {
Value v;
e->eval(*this, env, v); e->eval(*this, env, v);
if (v.type != tBool) if (v.type != tBool)
throwTypeError("value is %1% while a Boolean was expected", v); throwTypeError("value is %1% while a Boolean was expected", v);
@ -490,6 +489,13 @@ inline bool EvalState::evalBool(Env & env, Expr * e)
} }
inline bool EvalState::evalBool(Env & env, Expr * e)
{
Value v;
return evalBool(env, e, v);
}
inline void EvalState::evalAttrs(Env & env, Expr * e, Value & v) inline void EvalState::evalAttrs(Env & env, Expr * e, Value & v)
{ {
e->eval(*this, env, v); e->eval(*this, env, v);
@ -838,13 +844,13 @@ void ExprWith::eval(EvalState & state, Env & env, Value & v)
void ExprIf::eval(EvalState & state, Env & env, Value & v) void ExprIf::eval(EvalState & state, Env & env, Value & v)
{ {
(state.evalBool(env, cond) ? then : else_)->eval(state, env, v); (state.evalBool(env, cond, v) ? then : else_)->eval(state, env, v);
} }
void ExprAssert::eval(EvalState & state, Env & env, Value & v) void ExprAssert::eval(EvalState & state, Env & env, Value & v)
{ {
if (!state.evalBool(env, cond)) if (!state.evalBool(env, cond, v))
throwAssertionError("assertion failed at %1%", pos); throwAssertionError("assertion failed at %1%", pos);
body->eval(state, env, v); body->eval(state, env, v);
} }

1
src/libexpr/eval.hh
View file

@ -145,6 +145,7 @@ public:
/* Evaluation the expression, then verify that it has the expected /* Evaluation the expression, then verify that it has the expected
type. */ type. */
inline bool evalBool(Env & env, Expr * e, Value & v);
inline bool evalBool(Env & env, Expr * e); inline bool evalBool(Env & env, Expr * e);
inline void evalAttrs(Env & env, Expr * e, Value & v); inline void evalAttrs(Env & env, Expr * e, Value & v);