The intention is to check a section name different from
.gcc_except_table . Rather than using a linker script, use llvm-objcopy
--rename-section instead.
bolt/test/lit.local.cfg wants to use the system GCC installation but it
specifies a wrong triple ("linux" instead of "linux-gnu") and relies on
clangDriver's loose GCC installation detection to pick up "*-linux-gnu".
This loose behavior may not work. Use "linux-gnu" instead.
Note: neither "linux" nor "linux-gnu" detects "linux-musl" triples, so
these tests currently fail on musl based systems.
Other files changes are cosmetic.
CDSplit splits functions up to three ways: main fragment with no suffix,
and fragments with .cold and .warm suffixes.
Add .warm suffix to the regex used to recognize split fragments.
Test Plan: updated register-fragments-bolt-symbols.s
Then two tests rely on .interp being the first section.
llvm-bolt would crash if lld places .interp after .got
(f639b57f7993cadb82ee9c36f04703ae4430ed85).
For best portability, when a linker scripts specifies a SECTIONS
command, the first section for each PT_LOAD segment should be specified
with a MAXPAGESIZE alignment. Otherwise, linkers have freedom to decide
how to place orphan sections, which might break intention.
Update the folder titles for targets in the monorepository that have not
seen taken care of for some time. These are the folders that targets are
organized in Visual Studio and XCode (`set_property(TARGET <target>
PROPERTY FOLDER "<title>")`) when using the respective CMake's IDE
generator.
* Ensure that every target is in a folder
* Use a folder hierarchy with each LLVM subproject as a top-level folder
* Use consistent folder names between subprojects
* When using target-creating functions from AddLLVM.cmake, automatically
deduce the folder. This reduces the number of
`set_property`/`set_target_property`, but are still necessary when
`add_custom_target`, `add_executable`, `add_library`, etc. are used. A
LLVM_SUBPROJECT_TITLE definition is used for that in each subproject's
root CMakeLists.txt.
Disambiguate local functions using the containing file symbol in BAT
mode. Make local function naming consistent across BAT fdata and YAML
profiles.
Test Plan: updated register-fragments-bolt-symbols.s
To align YAML and fdata profiles produced in BAT mode, lift two
restrictions applied in non-relocation mode when BAT is present:
1) register secondary entry points from ignored functions,
2) treat functions with secondary entry points as simple.
This allows constructing CFG for non-simple functions in non-relocation
mode and emitting YAML profile for them, which can then be used for
optimizations in relocation mode.
Test Plan: added test ignored-interprocedural-reference.s
Exempt special symbols (hot text/data and _end symbol) from normal
handling. We only need to set their value and make them absolute.
If these symbols are handled as normal symbols and if they alias
functions we may create non-sensical symbols, e.g. __hot_start.cold.
Test Plan: updated hot-end-symbol.s
Reviewers: maksfb, rafaelauler, ayermolo, dcci
Reviewed By: dcci, maksfb
Pull Request: https://github.com/llvm/llvm-project/pull/92713
YAML profile for non-simple functions without CFG is
1) useless for optimizations,
2) can't be attached, similar to fdata profile,
3) would be reported as invalid/stale even if the profile is valid.
Don't attempt to attach the profile in this case, aligning the behavior
to DataReader.
Test Plan: added yaml-non-simple.test
Type unit DIE generated by clang contains DW_AT_comp_dir/DW_AT_dwo_name.
This was added to clang to help LLDB to figure out where type unit come
from when accessing an entry in a .debug_names accelerator table and
type units in .dwp file.
When BOLT writes out .dwo files it changes the name of them. User can
also specify directory of where they can be written out. Added support
to BOLT to update those attributes.
Switch from FuncBranchData intermediate maps (Intra/InterIndex)
to aggregated Data, same as one used by DataReader:
e62ce1f884/bolt/lib/Profile/DataReader.cpp (L385-L389)
This aligns the order of the output between YAMLProfileWriter and
writeBATYAML.
Test Plan: updated bolt-address-translation-yaml.test
Reviewers: rafaelauler, dcci, ayermolo, maksfb
Reviewed By: ayermolo, maksfb
Pull Request: https://github.com/llvm/llvm-project/pull/91289
Fix an issue where the profile for all branches that have a BRANCHENTRY
is dropped. If the branch has an entry in BAT, it will be translated to
its input offset. We used to only permit the basic block offset as a
branch source. Perform a lookup of containing basic block instead.
Test Plan: Updated bolt-address-translation-yaml.test
Reviewers: maksfb, dcci, rafaelauler, ayermolo
Reviewed By: maksfb
Pull Request: https://github.com/llvm/llvm-project/pull/91273
A compiler can generate a redundant indirection for a jump via a fixed
jump table target. Add a test case that covers such pattern that covers
PIC case. We already have non-PIC case detection.
Currently XFAIL.
Returns are ignored in perf/pre-aggregated/fdata profile reader (see
DataReader::convertBranchData). They are also omitted in
YAMLProfileWriter by virtue of not having the profile attached to them
in the reader, and YAMLProfileWriter converting the profile attached to
BinaryFunctions. Thus, return profile is universally ignored across all
profile types except BAT YAML.
To make returns ignored for YAML produced in BAT mode, we can:
1) ignore them in YAMLProfileReader,
2) omit them from YAML profile in profile conversion/writing.
The first option is prone to profile staleness issue, where the profiled
binary doesn't match the one to be optimized, and thus returns in the
profile can no longer be reliably detected (as we don't distinguish them
from calls in the profile).
The second option is robust to staleness but requires disassembling the
branch source instruction.
Test Plan: Updated bolt-address-translation-yaml.test
Reviewers: rafaelauler, dcci, ayermolo, maksfb
Reviewed By: maksfb
Pull Request: https://github.com/llvm/llvm-project/pull/90807
To match profile data to code we need to know branch instruction offsets
within a function. For this reason, we mark branches with the "Offset"
annotation while disassembling the code. However, _dynamic_ branches in
the Linux kernel could be NOPs in disassembled code, and we ignore them
while adding annotations. We need to explicitly add the "Offset"
annotation while creating dynamic branches.
Note that without this change, `getInstructionAtOffset()` would still
return a branch instruction if the offset matched the last instruction
in a basic block (and the profile data was matched correctly). However,
the function failed for cases when the searched instruction was followed
by an unconditional jump. "Offset" annotation solves this case.
Skip updating references for operands that do not directly
refer to jump table symbols but fall within a jump table's
address range to prevent unintended modifications.
Use known order of BOLT split function symbols: fragment symbols
immediately precede the parent fragment symbol.
Depends On: https://github.com/llvm/llvm-project/pull/89648
Test Plan: Added register-fragments-bolt-symbols.s
Fragment matching relies on symbol names to identify and register split
function fragments. However, as split fragments are often local symbols,
name aliasing is possible. For such cases, use symbol table to resolve
ambiguities.
This requires the presence of FILE symbols in the input binary. As BOLT
requires non-stripped binary, this is a reasonable assumption. Note that
`strip -g` removes FILE symbols by default, but `--keep-file-symbols`
can be used to preserve them.
Depends on: https://github.com/llvm/llvm-project/pull/89861
Test Plan:
Updated X86/fragment-lite.s
Temporary symbols generated for .eh_frame and .debug_line have an empty
name, which appear in .symtab in the presence of RISC-V style linker
relaxation and will not be discarded by ld/objcopy --discard-locals
(-X).
In contrast, GNU assembler's riscv port assigns a fake name ".L0 " (with
a trailing space) to these symbols so that will be discarded by
ld/objcopy --discard-locals.
This patch matches the GNU behavior. Since Clang's RISC-V targets pass
-X to ld, and GNU ld defaults to -X for RISC-V targets, these ".L0 "
symbols will be discarded after linking by default, as expected by
users.
The llvm-symbolizer special case for RISC-V `SF_FormatSpecific` symbols
https://reviews.llvm.org/D98669 needs to be adjusted.
Note: `"":` in assembly currently crashes.
When we rewrite dynamic relocations, there could be cases where they
reference code locations inside functions that were rewritten. When this
happens, we need to precisely map old address to a new one. Until we can
reliably perform the mapping, detect such condition and issue an error
refusing to write a broken binary.
If a jump table has entries at the end that are a result of
__builtin_unreachable() targets, BOLT can confuse them with function
pointers. In such case, we should exclude these targets from the table
as we risk incorrectly updating the function pointers. It is safe to
exclude them as branching on such targets is considered an undefined
behavior.
Call site information setting was conditioned on branch information
presence for a given block. However, it's possible to have sampled
profile lacking one or the other for a given basic block.
Iterate over branch profiles and call profiles independently to cover
all recorded profile data.
Depends on https://github.com/llvm/llvm-project/pull/87569
Test Plan: Updated bolt/test/X86/yaml-secondary-entry-discriminator.s
Reviewers: ayermolo, dcci, maksfb, rafaelauler
Reviewed By: maksfb
Pull Request: https://github.com/llvm/llvm-project/pull/87743
Move BAT parent function lookup outside `getLocationName`, to the
scope where we retrieve `FuncBranchData` linked with the function.
Previously DataAggregator would store branch profile recorded in the
split fragment in `FuncBranchData` associated with the fragment, and
perform name translation in `getLocationName` for symbol name only.
This works for fdata profile which is printed out as-is, but doesn't
work with BAT YAML profile writer which requires a combined profile.
The issue necessitated `fixupBATProfile` which partially addressed the
issue (reassigned inter-fragment calls back into intra-function
branches). However, `fixupBATProfile` fails to address disjoint
profiles (i.e. doesn't merge `FuncBranchData` for fragments back
into parent). This diff eliminates the need for `fixupBATProfile` by
removing the root cause of the issue.
Test Plan: NFC for existing tests
Reviewers: ayermolo, dcci, rafaelauler, maksfb
Reviewed By: maksfb
Pull Request: https://github.com/llvm/llvm-project/pull/87569
This fixes an issue where `PatchEntries` overwrites function body but
keeps CFI untouched. Existing FDEs thus become invalid. This doesn't
affect unwinding because patched functions are transparent from
EH/unwinding perspective, but it breaks BOLT during disassembling those
functions.
Emit empty FDE for injected functions (emitted to the same address as
.org functions) that take precedence over the original FDE.
This adds eh_frame overhead, but restores the ability to disassemble
.org functions. Note that the overhead is avoided in `-use-old-text`
mode.
Test Plan: updated bolt/test/X86/patch-entries.test
Reviewers: rafaelauler, maksfb, dcci, ayermolo
Reviewed By: maksfb, dcci
Pull Request: https://github.com/llvm/llvm-project/pull/87967
BAT writeMaps encoded the assumption that functions are only split into
two fragments (hot and cold). However, BOLT supports splitting into
arbitrary number of fragments. Relax that assumption and look up primary
(hot) fragment explicitly.
Depends on: https://github.com/llvm/llvm-project/pull/86219
Test Plan: Updated bolt/test/X86/yaml-secondary-entry-discriminator.s
Reviewers: ayermolo, rafaelauler, maksfb, dcci
Reviewed By: maksfb, dcci
Pull Request: https://github.com/llvm/llvm-project/pull/87123
Provide a mechanism to resolve call target information for calls from non-BAT
functions to BAT functions (`YAMLProfileWriter::convert`). Make it generic for
future use in BAT-to-BAT calls.
Test Plan: Updated bolt/test/X86/bolt-address-translation-yaml.test
Reviewers: ayermolo, maksfb, rafaelauler, dcci
Reviewed By: maksfb
Pull Request: https://github.com/llvm/llvm-project/pull/86219
Under normal circumstances, we terminate basic blocks on a trap
instruction. However, Linux kernel may resume execution after hitting a
trap (ud2 on x86). Thus, we introduce "--terminal-trap" option that will
specify if the trap instruction should terminate the control flow. The
option is on by default except for the Linux kernel mode when it's off.
