[DebugInfo,test] Convert text files from CRLF to LF

[CodeGen][AArch64] Set min jump table entries to 13 for AArch64 targets (#71166)

There are some workloads that are negatively impacted by using jump
tables when the number of entries is small. The

[CodeGen][AArch64] Set min jump table entries to 13 for AArch64 targets (#71166)

There are some workloads that are negatively impacted by using jump
tables when the number of entries is small. The SPEC2017 perlbench
benchmark is one example of this, where increasing the threshold to
around 13 gives a ~1.5% improvement on neoverse-v1. I chose the minimum
threshold based on empirical evidence rather than science, and just
manually increased the threshold until I got the best performance
without impacting other workloads. For neoverse-v1 I saw around ~0.2%
improvement in the SPEC2017 integer geomean, and no overall change for
neoverse-n1. If we find issues with this threshold later on we can
always revisit this.

The most significant SPEC2017 score changes on neoverse-v1 were:

500.perlbench_r: +1.6%
520.omnetpp_r: +0.6%

and the rest saw changes < 0.5%.

I updated CodeGen/AArch64/min-jump-table.ll to reflect the new
threshold. For most of the affected tests I manually set the min number
of entries back to 4 on the RUN line because the tests seem to rely upon
this behaviour.

show more ...

Emit the CodeView `S_ARMSWITCHTABLE` debug symbol for jump tables

The CodeView `S_ARMSWITCHTABLE` debug symbol is used to describe the layout of a jump table, it contains the following information:

Emit the CodeView `S_ARMSWITCHTABLE` debug symbol for jump tables

The CodeView `S_ARMSWITCHTABLE` debug symbol is used to describe the layout of a jump table, it contains the following information:

* The address of the branch instruction that uses the jump table.
* The address of the jump table.
* The "base" address that the values in the jump table are relative to.
* The type of each entry (absolute pointer, a relative integer, a relative integer that is shifted).

Together this information can be used by debuggers and binary analysis tools to understand what an jump table indirect branch is doing and where it might jump to.

Documentation for the symbol can be found in the Microsoft PDB library dumper: https://github.com/microsoft/microsoft-pdb/blob/0fe89a942f9a0f8e061213313e438884f4c9b876/cvdump/dumpsym7.cpp#L5518

This change adds support to LLVM to emit the `S_ARMSWITCHTABLE` debug symbol as well as to dump it out (for testing purposes).

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D149367

show more ...

Fix llvm/test/DebugInfo/COFF/jump-table.ll

Fix `llvm/test/DebugInfo/COFF/jump-table.ll` by adding `REQUIRES` clauses for all architectures used by the test.

Emit the CodeView `S_ARMSWITCHTABLE` debug symbol for jump tables

The CodeView `S_ARMSWITCHTABLE` debug symbol is used to describe the layout of a jump table, it contains the following information:

Emit the CodeView `S_ARMSWITCHTABLE` debug symbol for jump tables

The CodeView `S_ARMSWITCHTABLE` debug symbol is used to describe the layout of a jump table, it contains the following information:

* The address of the branch instruction that uses the jump table.
* The address of the jump table.
* The "base" address that the values in the jump table are relative to.
* The type of each entry (absolute pointer, a relative integer, a relative integer that is shifted).

Together this information can be used by debuggers and binary analysis tools to understand what an jump table indirect branch is doing and where it might jump to.

Documentation for the symbol can be found in the Microsoft PDB library dumper: https://github.com/microsoft/microsoft-pdb/blob/0fe89a942f9a0f8e061213313e438884f4c9b876/cvdump/dumpsym7.cpp#L5518

This change adds support to LLVM to emit the `S_ARMSWITCHTABLE` debug symbol as well as to dump it out (for testing purposes).

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D149367

show more ...