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yurys@chromium.org authored
Revert of Extend CPU profiler with mapping ticks to source lines (patchset #3 id:40001 of https://codereview.chromium.org/616963005/) Reason for revert: It broke layout test fast/events/window-onerror-02.html, error column reported by window.onerror is now wrong (I believe it is because of the change in full-codegen): http://build.chromium.org/p/client.v8/builders/V8-Blink%20Linux%2064%20%28dbg%29/builds/652 Original issue's description: > Extend CPU profiler with mapping ticks to source lines > > The idea behind of this solution is to use the existing "relocation info" instead of consumption the CodeLinePosition events emitted by the V8 compilers. > During generation code and relocation info are generated simultaneously. > When code generation is done you each code object has associated "relocation info". > Relocation information lets V8 to mark interesting places in the generated code: the pointers that might need to be relocated (after garbage collection), > correspondences between the machine program counter and source locations for stack walking. > > This patch: > 1. Add more source positions info in reloc info to make it suitable for source level mapping. > The amount of data should not be increased dramatically because (1) V8 already marks interesting places in the generated code and > (2) V8 does not write redundant information (it writes a pair (pc_offset, pos) only if pos is changed and skips other). > I measured it on Octane benchmark - for unoptimized code the number of source positions may achieve 2x ('lin_solve' from NavierStokes benchmark). > > 2. When a sample happens, CPU profiler finds a code object by pc, then use its reloc info to match the sample to a source line. > If a source line is found that hit counter is increased by one for this line. > > 3. Add a new public V8 API to get the hit source lines by CDT CPU profiler. > Note that it's expected a minor patch in Blink to pack the source level info in JSON to be shown. > > 4.Add a test that checks how the samples are distributed through source lines. > It tests two cases: (1) relocation info created during code generation and (2) relocation info associated with precompiled function's version. > > Patch from Denis Pravdin <denis.pravdin@intel.com> > BUG=None > LOG=Y > R=svenpanne@chromium.org > > Committed: https://code.google.com/p/v8/source/detail?r=24389 TBR=svenpanne@chromium.org,danno@chromium.org,alph@chromium.org,denis.pravdin@intel.com,weiliang.lin@intel.com BUG=None LOG=N Review URL: https://codereview.chromium.org/624443005 git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24394 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
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