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Hello,I'm trying to compile an old code with an AArch64 processor but it's leading to memory leaks. After some troubleshooting, I have been able to locate one potential hot spot that includes the following definitions:
#define MAXCHAR 255 #define MAXSHORT 32767 #define MINSHORT -32768 #define MAXTABLE 32500 #define BITS_PER_WORD 32 #define WORDSIZE(n) (((n)+(BITS_PER_WORD-1))/BITS_PER_WORD) #define BIT(r, n) ((((r)[(n)>>5])>>((n)&31))&1) #define SETBIT(r, n) ((r)[(n)>>5]|=((unsigned)1<<((n)&31)))
These values are unlikely to be accurate for an AArch64 CPU and I was wondering if anyone has any suggestions on what values to assign (note: the compiler is GCC-11). Thank you.
Hi @a.surati,The snippet is a component of a larger postprocessing tool (NCL) but it seems to be somewhat replicating BYACC. The memory leak seems to be coming from what they named as nyacc (github.com/.../nyacc), which probably stands for NCL Yacc. If these definitions are not the root of the issue, I wonder if some function is not passing (arrays of) unsigned integers as you mention. Thanks.
The latest byacc is available here. The latest change at this time is from Aug 2021, where the author acknowledges a fix for some memory leaks in its CHANGES file.
Some of these leaks may not be a problem. If the allocation is supposed to be done only once during the lifetime of the nyacc program, and there's no memory pressure, then freeing the memory isn't necessary - all memory utilized by the program gets freed anyways when it exits.
If one wants to change the macros, then the type of the corresponding arrays must also be changed from 'unsigned' to 'unsigned long'.
The modified macros are:
#define BITS_PER_WORD 64 #define BIT(r, n) ((((r)[(n)>>6])>>((n)&63))&1) #define SETBIT(r, n) ((r)[(n)>>6]|=((unsigned long)1<<((n)&63)))
Is it possible for NCL to just replace the nyacc with the latest available byacc? The nyacc package is indeed byacc, although an ancient one, as confirmed by the NO_WARRANTY license file included with nyacc.
Hi @a.surati. Unfortunately the developers haven't updated their Yacc over the years and, once you start pulling the thread, there are lots of things that could be modified or simply replaced. My guess is that substituting nyacc with the latest version of byacc would break not one but several things. Thanks.