How -fomit-frame-pointer gcc option could make debugging impossible?

2
votes

GCC online doc - 3.10 Options That Control Optimization affirm that -fomit-frame-pointer gcc option can make debbuging impossible.

-fomit-frame-pointer

Don't keep the frame pointer in a register for functions that don't need one. This avoids the instructions to save, set up and restore frame pointers; it also makes an extra register available in many functions. It also makes debugging impossible on some machines.

I understand why local variables are harder to locate and stack traces are much harder to reconstruct without a frame pointer to help out.

But, In what circumstances is it make debugging impossible?

1
gcc

1 Answers

0
votes

It may be impossible in the sense that existing tools for these platforms (which are often provided by platform vendor, not GNU) expect frame pointer to be present for successful unwinding. One could theoretically modify them to be more intelligent but in practice this is not possible.