Is there anyway to set the starting address of global/static data area?

[xbcnn]

Does anyone know if we can do this in Emscripten? I mean to keep a no man's zone before it, such as 64KB(a page).

[sbc100]

If you mean the start of the heap, then you can use address of the linker-generated symbol __heap_base... or you can use sbrk(0) to find out the current end of the heap.

If you mean the static data area then you can use the the address of the __global_base.

[xbcnn]

If you mean the static data area then you can use the the address of the __global_base.

Yeah, I mean this. Is it possible to change it, like by passing some linker options?

[sbc100]

If you mean the static data area then you can use the the address of the __global_base.

Yeah, I mean this. Is it possible to change it, like by passing some linker options?

Yes, you can build with -sGLOBAL_BASE=66560

[xbcnn]

Thank you @sbc100. It's nice.

[xbcnn]

@sbc100 One more question. Is there any way to detect load/storing to this no-man zone before the static data area?

[sbc100]

We do support -fsanitize=address which will detect any out-of-bounds access.

Also, if you build with -sASSERTIONS that will enabled -sSTACK_OVERFLOW_CHECK which will write magic values that we write to the very beginning of memory and these get checked at various points.

What exactly are you trying to achieve here?

Also, just FYI, I just made a change that, by default puts the stack first in debug builds, which then means that static data will come after the stack region in memory. See #18154