Re: Is it possible to make gcc detect whether printf prints floating point numbers?
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On 06/08/2012 10:57 AM, Bin.Cheng wrote: > On Fri, Jun 8, 2012 at 5:14 PM, Andrew Haley <aph@xxxxxxxxxx> wrote: >> [Redirect to gcc-help] >> >> On 06/08/2012 09:54 AM, Bin.Cheng wrote: >>> In micro-controller applications, code size is critical and the size >>> problem is worse if library is linked. >>> For example, most c programs call printf to format output data, that >>> means floating point code get linked even the program only want to >>> output non-floating point numbers. Currently, we rely on end-user to >>> call iprintf if the program does not want floating point. >>> >>> I noticed that GCC now can check format string of printf functions, so >>> I am wondering if it is possible to take advantage of this utility, by >>> making gcc detect whether printf prints floating point number and then >>> generate assembly directive in backend to pull in floating point >>> functions only if necessary. >> >> It wouldn't be at all difficult, but you'd have to change gcc. >> > > Thanks Andrew. > How about the question: > The check is done in front end, so how should I expose the check > result to back-end. I wouldn't. I'd just call printf or iprintf, depending on the use of floating-point. Andrew.