• tebbi's avatar
    [cpu-profiler] use new source position information for deoptimization in cpu profiler · 1b320d20
    tebbi authored
    The new SourcePosition class allows for precise tracking of source positions including the stack of inlinings. This CL makes the cpu profiler use this new information. Before, the cpu profiler used the deoptimization data to reconstruct the inlining stack. However, optimizing compilers (especially Turbofan) can hoist out checks such that the inlining stack of the deopt reason and the inlining stack of the position the deoptimizer jumps to can be different (the old cpu profiler tests and the ones introduced in this cl produce such situations for turbofan). In this case, relying on the deoptimization info produces paradoxical results, where the reported position is before the function responsible is called. Even worse, https://codereview.chromium.org/2451853002/ combines the precise position with the wrong inlining stack from the deopt info, leading to completely wrong results.
    
    Other changes in this CL:
    - DeoptInlinedFrame is no longer needed, because we can compute the correct inlining stack up front.
    - I changed the cpu profiler tests back to test situations where deopt checks are hoisted out in Turbofan and made them robust enough to handle the differences between Crankshaft and Turbofan.
    - I reversed the order of SourcePosition::InliningStack to make it match the cpu profiler convention.
    - I removed CodeDeoptEvent::position, as it is no longer used.
    
    R=alph@chromium.org
    
    BUG=v8:5432
    
    Review-Url: https://codereview.chromium.org/2503393002
    Cr-Commit-Position: refs/heads/master@{#41168}
    1b320d20
cpu-profiler-inl.h 1.79 KB