How can I rewrite the changed function in BOLT

Subprojects BOLT
1

I have increased the number of instructions of the function in my bolt pass. How can I rewrite the changed function? Now I get the following warning and no change in binary:

BOLT-WARNING: new function size (0x1b0) is larger than maximum allowed size (0x150) for function main

Thank you!

2

Or in other words, how are modified functions in BOLT rewritten?

3

Looks like you’re using use-old-text or no-relocs mode which attempt to rewrite the function in-place. Can you please show BOLT command line and the output?

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4

When the input binary lacks relocations saved by the linker under -q/--emit-relocs option, BOLT tries to overwrite the function in-place. If you can relink the input binary, then just add -q (-Wl,-q if invoking via the compiler). Otherwise, we’ll need to expand the capabilities to write new function body to a new segment in non-relocation mode.

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5

Thanks for your reply, the option -Wl,-q has solved my problem. And I think it’s a good idea to expand the capabilities to write new function body to a new segment in non-relocation mode. Sometimes we can’t relink the input binary.