This mostly follows LLVM's InstrProfReader.cpp error handling.
Previously, attempting to merge corrupted profile data would result in
crashes. See https://crbug.com/1216811#c4.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D104050
The linkage/visibility of `__profn_*` variables are derived
from the profiled functions.
extern_weak => linkonce
available_externally => linkonce_odr
internal => private
extern => private
_ => unchanged
The linkage/visibility of `__profc_*`/`__profd_*` variables are derived from
`__profn_*` with linkage/visibility wrestling for Windows.
The changes can be folded to the following without changing semantics.
```
if (TT.isOSBinFormatCOFF() && !NeedComdat) {
Linkage = GlobalValue::InternalLinkage;
Visibility = GlobalValue::DefaultVisibility;
}
```
That said, I think we can just delete the code block.
An extern/internal function will now use private `__profc_*`/`__profd_*`
variables, instead of internal ones. This saves some symbol table entries.
A non-comdat {linkonce,weak}_odr function will now use hidden external
`__profc_*`/`__profd_*` variables instead of internal ones. There is potential
object file size increase because such symbols need `/INCLUDE:` directives.
However such non-comdat functions are rare (note that non-comdat weak
definitions don't prevent duplicate definition error).
The behavior changes match ELF.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D103355
This reduces the size of chrome.dll.pdb built with optimizations,
coverage, and line table info from 4,690,210,816 to 2,181,128,192, which
makes it possible to fit under the 4GB limit.
This change can greatly reduce binary size in coverage builds, which do
not need value profiling. IR PGO builds are unaffected. There is a minor
behavior change for frontend PGO.
PGO and coverage both use InstrProfiling to create profile data with
counters. PGO records the address of each function in the __profd_
global. It is used later to map runtime function pointer values back to
source-level function names. Coverage does not appear to use this
information.
Recording the address of every function with code coverage drastically
increases code size. Consider this program:
void foo();
void bar();
inline void inlineMe(int x) {
if (x > 0)
foo();
else
bar();
}
int getVal();
int main() { inlineMe(getVal()); }
With code coverage, the InstrProfiling pass runs before inlining, and it
captures the address of inlineMe in the __profd_ global. This greatly
increases code size, because now the compiler can no longer delete
trivial code.
One downside to this approach is that users of frontend PGO must apply
the -mllvm -enable-value-profiling flag globally in TUs that enable PGO.
Otherwise, some inline virtual method addresses may not be recorded and
will not be able to be promoted. My assumption is that this mllvm flag
is not popular, and most frontend PGO users don't enable it.
Differential Revision: https://reviews.llvm.org/D102818
If there are no counters, an mmap() of the counters section would fail
due to the size argument being too small (EINVAL).
rdar://78175925
Differential Revision: https://reviews.llvm.org/D102735
We're having flaky failures on this test on the sanitizer slow
buildbot. Not per-run flaky, but it'll be green for a while, then red
for a while. I suspect that changes in codegen are causing the
LLVM_VP_MAX_NUM_VALS_PER_SITE=150 to be above and below the limit
sporadically. The limit on my machine using lld and a non-bootstrapped
compiler is 175, but the bot uses GNU ld and ld.gold at different
points, which could be affecting behaviour.
Change this threshold to LLVM_VP_MAX_NUM_VALS_PER_SITE=130 in order to
try and get it below the failure point, at least for the foreseeable
future.
http://lab.llvm.org:8011/#/builders/37/builds/2744
`__llvm_prf_vnodes` and `__llvm_prf_names` are used by runtime but not
referenced via relocation in the translation unit.
With `-z start-stop-gc` (LLD 13 (D96914); GNU ld 2.37 https://sourceware.org/bugzilla/show_bug.cgi?id=27451),
the linker does not let `__start_/__stop_` references retain their sections.
Place `__llvm_prf_vnodes` and `__llvm_prf_names` in `llvm.used` to make
them retained by the linker.
This patch changes most existing `UsedVars` cases to `CompilerUsedVars`
to reflect the ideal state - if the binary format properly supports
section based GC (dead stripping), `llvm.compiler.used` should be sufficient.
`__llvm_prf_vnodes` and `__llvm_prf_names` are switched to `UsedVars`
since we want them to be unconditionally retained by both compiler and linker.
Behaviors on COFF/Mach-O are not affected.
Reviewed By: davidxl
Differential Revision: https://reviews.llvm.org/D97649
`__llvm_prf_vnodes` and `__llvm_prf_names` are used by runtime but not
referenced via relocation in the translation unit.
With `-z start-stop-gc` (D96914 https://sourceware.org/bugzilla/show_bug.cgi?id=27451),
the linker no longer lets `__start_/__stop_` references retain them.
Place `__llvm_prf_vnodes` and `__llvm_prf_names` in `llvm.used` to make
them retained by the linker.
This patch changes most existing `UsedVars` cases to `CompilerUsedVars`
to reflect the ideal state - if the binary format properly supports
section based GC (dead stripping), `llvm.compiler.used` should be sufficient.
`__llvm_prf_vnodes` and `__llvm_prf_names` are switched to `UsedVars`
since we want them to be unconditionally retained by both compiler and linker.
Behaviors on other COFF/Mach-O are not affected.
Differential Revision: https://reviews.llvm.org/D97649
Fix a buffer overrun that can occur when parsing '%c' at the end of a
filename pattern string.
rdar://74571261
Reviewed By: kastiglione
Differential Revision: https://reviews.llvm.org/D97239
Depending on the order in which lld and compiler-rt projects are
processed by CMake, `TARGET lld` might evaluate to `TRUE` or `FALSE`
even though `lld-available` lit stanza is always set because lld is
being built. We check whether lld project is enabled instead which
is used by other compiler-rt tests.
The ideal solution here would be to use CMake generator expressions,
but those cannot be used for dependencies yet, see:
https://gitlab.kitware.com/cmake/cmake/-/issues/19467
Differential Revision: https://reviews.llvm.org/D97256
__start_/__stop_ references retain C identifier name sections such as
__llvm_prf_*. Putting these into a section group disables this logic.
The ELF section group semantics ensures that group members are retained
or discarded as a unit. When a function symbol is discarded, this allows
allows linker to discard counters, data and values associated with that
function symbol as well.
Note that `noduplicates` COMDAT is lowered to zero-flag section group in
ELF. We only set this for functions that aren't already in a COMDAT and
for those that don't have available_externally linkage since we already
use regular COMDAT groups for those.
Differential Revision: https://reviews.llvm.org/D96757
__start_/__stop_ references retain C identifier name sections such as
__llvm_prf_*. Putting these into a section group disables this logic.
The ELF section group semantics ensures that group members are retained
or discarded as a unit. When a function symbol is discarded, this allows
allows linker to discard counters, data and values associated with that
function symbol as well.
Note that `noduplicates` COMDAT is lowered to zero-flag section group in
ELF. We only set this for functions that aren't already in a COMDAT and
for those that don't have available_externally linkage since we already
use regular COMDAT groups for those.
Differential Revision: https://reviews.llvm.org/D96757
C identifier name input sections such as __llvm_prf_* are GC roots so
they cannot be discarded. In LLD, the SHF_LINK_ORDER flag overrides the
C identifier name semantics.
The !associated metadata may be attached to a global object declaration
with a single argument that references another global object, and it
gets lowered to SHF_LINK_ORDER flag. When a function symbol is discarded
by the linker, setting up !associated metadata allows linker to discard
counters, data and values associated with that function symbol.
Note that !associated metadata is only supported by ELF, it does not have
any effect on non-ELF targets.
Differential Revision: https://reviews.llvm.org/D76802
C identifier name input sections such as __llvm_prf_* are GC roots so
they cannot be discarded. In LLD, the SHF_LINK_ORDER flag overrides the
C identifier name semantics.
The !associated metadata may be attached to a global object declaration
with a single argument that references another global object, and it
gets lowered to SHF_LINK_ORDER flag. When a function symbol is discarded
by the linker, setting up !associated metadata allows linker to discard
counters, data and values associated with that function symbol.
Note that !associated metadata is only supported by ELF, it does not have
any effect on non-ELF targets.
Differential Revision: https://reviews.llvm.org/D76802
llvm-cov -path-equivalence=/tmp,... is used by some checked-in coverage mapping
files where the original filename is under /tmp. If the test itself produces the
coverage mapping file, there is no need for /tmp.
For coverage_emptylines.cpp: the source filename is under the build directory.
If the build directory is under /tmp, the path mapping will make
llvm-cov fail to find the file.
CallInst::updateProfWeight() creates branch_weights with i64 instead of i32.
To be more consistent everywhere and remove lots of casts from uint64_t
to uint32_t, use i64 for branch_weights.
Reviewed By: davidxl
Differential Revision: https://reviews.llvm.org/D88609
CallInst::updateProfWeight() creates branch_weights with i64 instead of i32.
To be more consistent everywhere and remove lots of casts from uint64_t
to uint32_t, use i64 for branch_weights.
Reviewed By: davidxl
Differential Revision: https://reviews.llvm.org/D88609
Add support for expanding the %t filename specifier in LLVM_PROFILE_FILE
to the TMPDIR environment variable. This is supported on all platforms.
On Darwin, TMPDIR is used to specify a temporary application-specific
scratch directory. When testing apps on remote devices, it can be
challenging for the host device to determine the correct TMPDIR, so it's
helpful to have the runtime do this work.
rdar://68524185
Differential Revision: https://reviews.llvm.org/D87332
gcov is an "Edge Profiling with Edge Counters" application according to
Optimally Profiling and Tracing Programs (1994).
The minimum number of counters necessary is |E|-(|V|-1). The unmeasured edges
form a spanning tree. Both GCC --coverage and clang -fprofile-generate leverage
this optimization. This patch implements the optimization for clang --coverage.
The produced .gcda files are much smaller now.
As reported in Bug 42535, `clang` doesn't inline atomic ops on 32-bit
Sparc, unlike `gcc` on Solaris. In a 1-stage build with `gcc`, only two
testcases are affected (currently `XFAIL`ed), while in a 2-stage build more
than 100 tests `FAIL` due to this issue.
The reason for this `gcc`/`clang` difference is that `gcc` on 32-bit
Solaris/SPARC defaults to `-mpcu=v9` where atomic ops are supported, unlike
with `clang`'s default of `-mcpu=v8`. This patch changes `clang` to use
`-mcpu=v9` on 32-bit Solaris/SPARC, too.
Doing so uncovered two bugs:
`clang -m32 -mcpu=v9` chokes with any Solaris system headers included:
/usr/include/sys/isa_defs.h:461:2: error: "Both _ILP32 and _LP64 are defined"
#error "Both _ILP32 and _LP64 are defined"
While `clang` currently defines `__sparcv9` in a 32-bit `-mcpu=v9`
compilation, neither `gcc` nor Studio `cc` do. In fact, the Studio 12.6
`cc(1)` man page clearly states:
These predefinitions are valid in all modes:
[...]
__sparcv8 (SPARC)
__sparcv9 (SPARC -m64)
At the same time, the patch defines `__GCC_HAVE_SYNC_COMPARE_AND_SWAP_[1248]`
for a 32-bit Sparc compilation with any V9 cpu. I've also changed
`MaxAtomicInlineWidth` for V9, matching what `gcc` does and the Oracle
Developer Studio 12.6: C User's Guide documents (Ch. 3, Support for Atomic
Types, 3.1 Size and Alignment of Atomic C Types).
The two testcases that had been `XFAIL`ed for Bug 42535 are un-`XFAIL`ed
again.
Tested on `sparcv9-sun-solaris2.11` and `amd64-pc-solaris2.11`.
Differential Revision: https://reviews.llvm.org/D86621
For a CFG G=(V,E), Knuth describes that by Kirchoff's circuit law, the minimum
number of counters necessary is |E|-(|V|-1). The emitted edges form a spanning
tree. libgcov emitted .gcda files leverages this optimization while clang
--coverage's doesn't.
Propagate counts by Kirchhoff's circuit law so that llvm-cov gcov can
correctly print line counts of gcc --coverage emitted files and enable
the future improvement of clang --coverage.
Two tests `FAIL` on 32-bit sparc:
Profile-sparc :: Posix/instrprof-gcov-parallel.test
UBSan-Standalone-sparc :: TestCases/Float/cast-overflow.cpp
The failure mode is similar:
Undefined first referenced
symbol in file
__atomic_store_4 /var/tmp/instrprof-gcov-parallel-6afe8d.o
__atomic_load_4 /var/tmp/instrprof-gcov-parallel-6afe8d.o
Undefined first referenced
symbol in file
__atomic_load_1 /var/tmp/cast-overflow-72a808.o
This is a known bug: `clang` doesn't inline atomics on 32-bit sparc, unlike
`gcc`.
The patch therefore `XFAIL`s the tests.
Tested on `sparcv9-sun-solaris2.11` and `amd64-pc-solaris2.11`.
Differential Revision: https://reviews.llvm.org/D85346
Similarly as for pointers, even for integers a == b is usually false.
GCC also uses this heuristic.
Reviewed By: ebrevnov
Differential Revision: https://reviews.llvm.org/D85781
Fangrui Song