[Lldb-commits] [PATCH] Profile Assembly Until Ret Instruction

[Tong Shen]

Hi Molenda, lldb-commits,

For now, x86 assembly profiler will stop after 10 "non-prologue"
instructions. In practice it may not be sufficient. For example, we have a
hand-written assembly function, which have hundreds of instruction before
actual (stack-adjusting) prologue instructions.

One way is to change the limit to 1000; but there will always be functions
that break the limit :-) I believe the right thing to do here is parsing
all instructions before "ret"/"call" as prologue instructions.

Here's what I changed:
- For "push %rbx" and "mov %rbx, -8(%rbp)": only add first row for that
register. They may appear multiple times in function body. But as long as
one of them appears, first appearance should be in prologue(If it's not in
prologue, this function will not use %rbx, so these 2 instructions should
not appear at all).
- Also monitor "add %rsp 0x20".
- Remove non prologue instruction count.
- Add "call" instruction detection, and stop parsing after it.

Thanks.

-- 
Best Regards, Tong Shen
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