[Lldb-commits] [PATCH] D17535: [LLDB][MIPS] Single step atomic sequences

Bhushan Attarde via lldb-commits lldb-commits at lists.llvm.org
Wed Feb 24 04:00:15 PST 2016

bhushan added a comment.

In MIPS, we can not put a breakpoint in middle of an atomic sequence.
If we do so (and that breakpoint is hit) then continuing from breakpoint address will cause "SC" to fail due to a breakpoint exception.
SC fails when there’s been any exception serviced since the LL. This will then become a "never ending" sequence.

Similarly when doing assembly level debugging of an atomic sequence if we step only 1 instruction (as we are debugging assembly code)
we will end up putting breakpoint on next instruction (within atomic sequence) and will cause "SC" to fail because of reason mentioned above.

That means an atomic sequence, starting with LL and ending with SC needs to be treated as a "single instruction block".



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