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Why does this endup in DRAM instead of flash?

Posted: Wed Nov 06, 2019 5:12 pm
by greengnu
I'm currently trying to compile a library for the esp32. Some parts already work, but I'm overruning dram when linking. I changed the esp32_out.ld file to fake more available dram, so I can link and inspect the resulting firmware.elf

I see that the following definitions end up in dram:

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    const ResizeFunc lanczos4_tab[] =
        resizeGeneric_<HResizeLanczos4<uchar, int, short>,
            VResizeLanczos4<uchar, int, short,
            FixedPtCast<int, uchar, INTER_RESIZE_COEF_BITS*2>,
            VResizeNoVec> >,
        resizeGeneric_<HResizeLanczos4<ushort, float, float>,
            VResizeLanczos4<ushort, float, float, Cast<float, ushort>,
            VResizeLanczos4Vec_32f16u> >,
        resizeGeneric_<HResizeLanczos4<short, float, float>,
            VResizeLanczos4<short, float, float, Cast<float, short>,
            VResizeLanczos4Vec_32f16s> >,
        resizeGeneric_<HResizeLanczos4<float, float, float>,
            VResizeLanczos4<float, float, float, Cast<float, float>,
            VResizeLanczos4Vec_32f> >,
        resizeGeneric_<HResizeLanczos4<double, double, float>,
            VResizeLanczos4<double, double, float, Cast<double, double>,
            VResizeNoVec> >,

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3ffed108	l	O	.dram0.bss	40000	_ZN2cvL13Lanczos4Tab_fE
3ffcd106	l	O	.dram0.bss	20000	_ZN2cvL13Lanczos4Tab_iE
40035108	l	O	.dram0.bss	10000	_ZN2cvL12BicubicTab_fE
4002d108	l	O	.dram0.bss	8000	_ZN2cvL12BicubicTab_iE
40047108	l	O	.dram0.bss	4000	_ZN2cvL13BilinearTab_fE
40045108	l	O	.dram0.bss	2000	_ZN2cvL13BilinearTab_iE
The definition of ResizeFunc is

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typedef void (*ResizeFunc)( const Mat& src, Mat& dst,
                            const int* xofs, const void* alpha,
                            const int* yofs, const void* beta,
                            int xmin, int xmax, int ksize );
I marked them with const - shouldn't they be put in flash then rather than dram?

I also don't really get how this array can end up being 260kb in size...

I should add: I'm first compiling the library into a static .a library before then linking it into my app

uuuuh, i just noticed that the library defines these arrays in a namespace named "hal". I take it that's the source of the problem? It's not compiled into a library named libhal.a however

Re: Why does this endup in DRAM instead of flash?

Posted: Thu Nov 07, 2019 2:50 am
by ESP_Angus
Hi greengnu,

What is the library named?

Could you please post the .map file from your project? This should give some clues about which linker rules, if any, were applied when linking these symbols.

Also, if you dump the unlinked .a file contents then what sections do these symbols belong to before they are linked?