1. 21 May, 2020 1 commit
    • Seth Brenith's avatar
      [diagnostics] Support --turbo-profiling for builtins · 18c73676
      Seth Brenith authored
      Currently, if d8 is run with the --turbo-profiling flag, it prints info
      about every TurboFan-compiled function. This info includes the number of
      times that each basic block in the function was run. It also includes
      text representations of the function's schedule and code, so that the
      person reading the output can associate counters with blocks of code.
      
      The data about each function is currently stored in a
      BasicBlockProfiler::Data instance, which is attached to a list owned by
      the singleton BasicBlockProfiler. Each Data contains an
      std::vector<uint32_t> which represents how many times each block in the
      function has executed. The generated code for each block uses a raw
      pointer into the storage of that vector to implement incrementing the
      counter.
      
      With this change, if you compile with v8_enable_builtins_profiling and
      then run with --turbo-profiling, d8 will print that same info about
      builtins too.
      
      In order to generate code that can survive being serialized to a
      snapshot and reloaded, this change uses counters in the JS heap instead
      of a std::vector outside the JS heap. The steps for instrumentation are
      as follows:
      
      1. Between scheduling and instruction selection, add code to increment
         the counter for each block. The counters array doesn't yet exist at
         this point, and allocation is disallowed, so at this point the code
         refers to a special marker value.
      2. During finalization of the code, allocate a BasicBlockProfilingData
         object on the JS heap containing data equivalent to what is stored in
         BasicBlockProfiler::Data. This includes a ByteArray that is big
         enough to store the counters for each block.
      3. Patch the reference in the BuiltinsConstantsTableBuilder so that
         instead of referring to the marker object, it now refers to this
         ByteArray. Also add the BasicBlockProfilingData object to a list that
         is attached to the heap roots so it can be easily accessed for
         printing.
      
      Because these steps include modifying the BuiltinsConstantsTableBuilder,
      this procedure is only applicable to builtins. Runtime-generated code
      still uses raw pointers into std::vector instances. In order to keep
      divergence between these code paths to a minimum, most work is done
      referring to instances of BasicBlockProfiler::Data (the C++ class), and
      functions are provided to copy back and forth between that type and
      BasicBlockProfilingData (the JS heap object).
      
      This change is intended only to make --turbo-profiling work consistently
      on more kinds of functions, but with some further work, this data could
      form the basis for:
      - code coverage info for fuzzers, and/or
      - hot-path info for profile-guided optimization.
      
      Bug: v8:10470, v8:9119
      Change-Id: Ib556a5bc3abe67cdaa2e3ee62702a2a08b11cb61
      Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2159738
      Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
      Reviewed-by: 's avatarUlan Degenbaev <ulan@chromium.org>
      Reviewed-by: 's avatarJakob Gruber <jgruber@chromium.org>
      Cr-Commit-Position: refs/heads/master@{#67944}
      18c73676
  2. 23 May, 2019 1 commit
  3. 20 May, 2019 1 commit
  4. 17 May, 2019 2 commits
  5. 04 Apr, 2018 1 commit
  6. 02 Feb, 2018 1 commit
  7. 15 Nov, 2017 1 commit
  8. 11 Aug, 2015 1 commit
    • mstarzinger's avatar
      Remove several grab-bag includes from the v8.h header. · 58109a2c
      mstarzinger authored
      This is the first step of turning the v8.h file into a normal header
      instead of an include-the-world header. The new rule is that no other
      header files are allowed to include v8.h, which is enforced by DEPS.
      
      Also the number of includes inside the v8.h file has been drastically
      reduced. Basically the last missing piece is the inclusion of the big
      objects-inl.h file.
      
      This in turn makes many headers follow the IWYU principle.
      
      R=bmeurer@chromium.org,hpayer@chromium.org,titzer@chromium.org
      
      Review URL: https://codereview.chromium.org/1282503003
      
      Cr-Commit-Position: refs/heads/master@{#30102}
      58109a2c
  9. 09 Feb, 2015 1 commit
  10. 29 Sep, 2014 1 commit