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Differential D118284

[BOLT][docs] Add note regarding DWARF v5 support to README.md
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Authored by maksfb on Jan 26 2022, 2:05 PM.

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ayermolo
Amir
yota9
rafauler
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rGd97fcf3df211: [BOLT][docs] Add note regarding DWARF v5 support to README.md

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This revision is now accepted and ready to land.Jan 26 2022, 2:09 PM
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This revision was landed with ongoing or failed builds.Jan 26 2022, 2:20 PM
Closed by commit rGd97fcf3df211: [BOLT][docs] Add note regarding DWARF v5 support to README.md (authored by maksfb). · Explain Why
This revision was automatically updated to reflect the committed changes.
maksfb added a commit: rGd97fcf3df211: [BOLT][docs] Add note regarding DWARF v5 support to README.md.
Harbormaster completed remote builds in B145846: Diff 403400.Jan 27 2022, 5:59 AM

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transfer (e.g., jump tables), the code patterns should be matching those transfer (e.g., jump tables), the code patterns should be matching those
generated by Clang/GCC. generated by Clang/GCC.
NOTE: BOLT is currently incompatible with the `-freorder-blocks-and-partition` NOTE: BOLT is currently incompatible with the `-freorder-blocks-and-partition`
compiler option. Since GCC8 enables this option by default, you have to compiler option. Since GCC8 enables this option by default, you have to
explicitly disable it by adding `-fno-reorder-blocks-and-partition` flag if explicitly disable it by adding `-fno-reorder-blocks-and-partition` flag if
you are compiling with GCC8 or above. you are compiling with GCC8 or above.
NOTE2: DWARF v5 is the new debugging format generated by the latest LLVM and GCC
compilers. It offers several benefits over the previous DWARF v4. Currently, the
support for v5 is a work in progress for BOLT. While you will be able to
optimize binaries produced by the latest compilers, until the support is
complete, you will not be able to update the debug info with
`-update-debug-sections`. To temporarily work around the issue, we recommend
compiling binaries with `-gdwarf-4` option that forces DWARF v4 output.
PIE and .so support has been added recently. Please report bugs if you PIE and .so support has been added recently. Please report bugs if you
encounter any issues. encounter any issues.
## Installation ## Installation
### Docker Image ### Docker Image
You can build and use the docker image containing BOLT using our [docker file](utils/docker/Dockerfile). You can build and use the docker image containing BOLT using our [docker file](utils/docker/Dockerfile).
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