On Oct 30, 2008, at 9:44 PM, Zhongxing Xu wrote:
On Fri, Oct 31, 2008 at 12:27 PM, Ted Kremenek <[EMAIL PROTECTED]>
wrote:
On Oct 30, 2008, at 7:56 PM, Zhongxing Xu wrote:
Hi Ted,
Would visiting the InitList from right to left lead to some bugs?
For example:
int x = 3;
int a[3] = {1, x = 1, 2*x+3};
At last a should be { 1, 1, 5 }. But visit from right to left
results { 1, 1, 9 }
I don't think the order of evaluation is defined (we should consult
the standard). If there is an explicit control-flow dependency
between the subexpressions, we should put that explicitly in the
CFG. In that case visiting the subexpressions from right-to-left or
left-to-right won't matter (as the expressions will have already
been evaluated).
Agree.
Another thing I thought of is cases like the following:
int a[3] = { x = (y = 2 * x), (x = 2 * y) ? 4 : 5, x };
Here there is a bunch of control-flow, but because of the ? operator
the expression "(x = 2 * y) ? 4" will always be evaluated first (since
it is hoisted in the CFG as a block-level expression), even if we did
left-to-right visitation of the the subexpressions of the
InitListExpr. Thus the only way to ensure a fixed order of evaluation
is to put it in the CFG (i.e., we couldn't do it in GRExprEngine even
if we wanted to)._______________________________________________
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