We need the compiler generated variable to override the weak symbol of
the same name inside the profile runtime, but using LinkOnceODRLinkage
results in weak symbol being emitted which leads to an issue where the
linker might choose either of the weak symbols potentially disabling the
runtime counter relocation.
This change replaces the use of weak definition inside the runtime with
an external weak reference to address the issue. We also place the
compiler generated symbol inside a COMDAT group so dead definition can
be garbage collected by the linker.
Differential Revision: https://reviews.llvm.org/D105176
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
When building with Clang 11 on Windows, silence the following:
[432/5643] Building C object projects\compiler-rt\lib\profile\CMakeFiles\clang_rt.profile-x86_64.dir\GCDAProfiling.c.obj
F:\aganea\llvm-project\compiler-rt\lib\profile\GCDAProfiling.c(464,13): warning: comparison of integers of different signs: 'uint32_t' (aka 'unsigned int') and 'int' [-Wsign-compare]
if (val != (gcov_version >= 90 ? GCOV_TAG_OBJECT_SUMMARY
~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 warning generated.
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
They were added so that if no metadata section is present,
`__start_llvm_prf_*` references would not cause "undefined symbol"
errors. By switching to undefined weak symbols in D96936, the dummy
sections are not needed.
This patch is also needed to work around
https://sourceware.org/bugzilla/show_bug.cgi?id=27490
Differential Revision: https://reviews.llvm.org/D97648
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
To make a kind of metadata section usage work, we want to drop the
`__start_/__stop_ references retain C identifier name sections` rule from LLD (see D96914).
If an application has no `__llvm_prf_data` input section surviving --gc-sections,
LLD will error for undefined hidden `{__start_,__stop_}__llvm_prf_*` from `libclang_rt.profile-*`.
Other `__llvm_prf_*` sections have similar issues.
Making the references weak can address the problem.
This probably enables the opportunity to drop zero size dummy sections in `InstrProfilingPlatformLinux.c`.
Reviewed By: davidxl
Differential Revision: https://reviews.llvm.org/D96936
D14468 added these dummy sections. This patch adds `__attribute__((used))` so
that when compiled by GCC>=11 or (expected, D96838) Clang>=13 on some ELF platforms,
these sections will get SHF_GNU_RETAIN to make sure they will not be discarded
by ld --gc-sections.
We are trying to get rid of LLD's "__start_/__stop_ references retain C identifier name sections" rule.
If LLD drops the rule in the future (we will retain compatibility for `__llvm_prf_*` for a while),
`__llvm_prf_*` will need to have the SHF_GNU_RETAIN flag, otherwise:
```
// __llvm_prf_cnts/__llvm_prf_data usually exist, but {names,vnds} may not exist.
// Such diagnostics will happen with {cnts,data} as well if no input object file is instrumented.
% clang++ -fprofile-generate a.cc -fuse-ld=lld -Wl,--gc-sections
ld.lld: error: undefined hidden symbol: __start___llvm_prf_names
>>> referenced by InstrProfilingPlatformLinux.c
>>> InstrProfilingPlatformLinux.c.o:(__llvm_profile_begin_names) in archive /tmp/RelA/lib/clang/13.0.0/lib/linux/libclang_rt.profile-x86_64.a
...
```
Differential Revision: https://reviews.llvm.org/D96902
Following up D81682 and D83903, remove the code for the old value profiling
buckets, which have been replaced with the new, extended buckets and disabled by
default.
Also syncing InstrProfData.inc between compiler-rt and llvm.
Differential Revision: https://reviews.llvm.org/D88838
While sanitizers don't use C++ standard library, we could still end
up accidentally including or linking it just by the virtue of using
the C++ compiler. Pass -nostdinc++ and -nostdlib++ to avoid these
accidental dependencies.
Differential Revision: https://reviews.llvm.org/D88922
Summary:
According the mmap man page (https://man7.org/linux/man-pages/man2/mmap.2.html) is only required to precisely control updates, so we can safely remove it.
Since gcda files are dumped just before to call exec** functions, dump need to be fast.
On my computer, Firefox built with --coverage needs ~1min40 to display something and in removing msync it needs ~8s.
Reviewers: void
Subscribers: #sanitizers, marco-c, sylvestre.ledru
Tags: #sanitizers
Differential Revision: https://reviews.llvm.org/D81060
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
This reverts commit 01cdab0b33.
It was causing the instrprof-darwin-exports.c test to fail.
```
Undefined symbols for architecture x86_64:
"_flush_fn_list", referenced from:
-exported_symbol[s_list] command line option
```
Extend the memop value profile buckets to be more flexible (could accommodate a
mix of individual values and ranges) and to cover more value ranges (from 11 to
22 buckets).
Disabled behind a flag (to be enabled separately) and the existing code to be
removed later.
Differential Revision: https://reviews.llvm.org/D81682
Currently, several InstrProf tests `FAIL` on Solaris (both sparc and x86):
Profile-i386 :: Posix/instrprof-visibility.cpp
Profile-i386 :: instrprof-merging.cpp
Profile-i386 :: instrprof-set-file-object-merging.c
Profile-i386 :: instrprof-set-file-object.c
On sparc there's also
Profile-sparc :: coverage_comments.cpp
The failure mode is always the same:
error: /var/llvm/local-amd64/projects/compiler-rt/test/profile/Profile-i386/Posix/Output/instrprof-visibility.cpp.tmp: Failed to load coverage: Malformed coverage data
The error is from `llvm/lib/ProfileData/Coverage/CoverageMappingReader.cpp`
(`loadBinaryFormat`), l.926:
InstrProfSymtab ProfileNames;
std::vector<SectionRef> NamesSectionRefs = *NamesSection;
if (NamesSectionRefs.size() != 1)
return make_error<CoverageMapError>(coveragemap_error::malformed);
where .size() is 2 instead.
Looking at the executable, I find (with `elfdump -c -N __llvm_prf_names`):
Section Header[15]: sh_name: __llvm_prf_names
sh_addr: 0x8053ca5 sh_flags: [ SHF_ALLOC ]
sh_size: 0x86 sh_type: [ SHT_PROGBITS ]
sh_offset: 0x3ca5 sh_entsize: 0
sh_link: 0 sh_info: 0
sh_addralign: 0x1
Section Header[31]: sh_name: __llvm_prf_names
sh_addr: 0x8069998 sh_flags: [ SHF_WRITE SHF_ALLOC ]
sh_size: 0 sh_type: [ SHT_PROGBITS ]
sh_offset: 0x9998 sh_entsize: 0
sh_link: 0 sh_info: 0
sh_addralign: 0x1
Unlike GNU `ld` (which primarily operates on section names) the Solaris
linker, following the ELF spirit, only merges input sections into an output
section if both section name and section flags match, so two separate
sections are maintained.
The read-write one comes from `lib/clang/12.0.0/lib/sunos/libclang_rt.profile-i386.a(InstrProfilingPlatformLinux.c.o)`
while the read-only one is generated by
`llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp` (`InstrProfiling::emitNameData`)
at l.1004 where `isConstant = true`.
The easiest way to avoid the mismatch is to change the definition in
`compiler-rt/lib/profile/InstrProfilingPlatformLinux.c` to `const`.
This fixes all failures observed.
Tested on `amd64-pc-solaris2.11`, `sparcv9-sun-solaris2.11`, and
`x86_64-pc-linux-gnu`.
Differential Revision: https://reviews.llvm.org/D85116
The root cause was fixed by 3d6f53018f.
The workaround added in 99ad956fda can be changed
to an assert now. (In case the fix regresses, there will be a heap-use-after-free.)
InstrProfilingBuffer.c.o is generic code that must support compilation
into freestanding projects. This gets rid of its dependence on the
_getpagesize symbol from libc, shifting it to InstrProfilingFile.c.o.
This fixes a build failure seen in a firmware project.
rdar://66249701
A malloc implementation may return a pointer to some allocated space. It is
undefined for libclang_rt.profile- to access the object - which actually happens
in instrumentTargetValueImpl, where ValueCounters[CounterIndex] may access a
ValueProfNode (from another allocated object) and crashes when the code accesses
the object referenced by CurVNode->Next.
This reverts commit 4a539faf74.
There is a __llvm_profile_instrument_range related crash in PGO-instrumented clang:
```
(gdb) bt
llvm::ConstantRange const&, llvm::APInt const&, unsigned int, bool) ()
llvm::ScalarEvolution::getRangeForAffineAR(llvm::SCEV const*, llvm::SCEV
const*, llvm::SCEV const*, unsigned int) ()
```
(The body of __llvm_profile_instrument_range is inlined, so we can only find__llvm_profile_instrument_target in the trace)
```
23│ 0x000055555dba0961 <+65>: nopw %cs:0x0(%rax,%rax,1)
24│ 0x000055555dba096b <+75>: nopl 0x0(%rax,%rax,1)
25│ 0x000055555dba0970 <+80>: mov %rsi,%rbx
26│ 0x000055555dba0973 <+83>: mov 0x8(%rsi),%rsi # %rsi=-1 -> SIGSEGV
27│ 0x000055555dba0977 <+87>: cmp %r15,(%rbx)
28│ 0x000055555dba097a <+90>: je 0x55555dba0a76 <__llvm_profile_instrument_target+342>
```
Most of the code in compiler_rt is C code. However, clang_rt.profile
contains the InstrProfilingRuntime.cpp file, which builds as C++. This
means that including e.g. <stdint.h> will actually include libc++'s
<stdint.h> and then #include_next the system's <stdint.h>. However, if
the target we're building compiler-rt for isn't supported by libc++,
this will lead to a failure since libc++'s <stdint.h> includes <__config>,
which performs various checks.
Since the goal seems to *not* be including any header from the C++ Standard
Library in clang_rt.profile, using -nostdinc++ to ensure that doesn't
happen unknowingly seems to make sense.
rdar://65852694
Differential Revision: https://reviews.llvm.org/D84205
GCC r187297 (2012-05) introduced `__gcov_dump` and `__gcov_reset`.
`__gcov_flush = __gcov_dump + __gcov_reset`
The resolution to https://gcc.gnu.org/PR93623 ("No need to dump gcdas when forking" target GCC 11.0) removed the unuseful and undocumented __gcov_flush.
Close PR38064.
Reviewed By: calixte, serge-sans-paille
Differential Revision: https://reviews.llvm.org/D83149
Similar to the reason behind moving __llvm_profile_filename into a
separate file[1]. When users try to use Full LTO with BFD linker to
generate IR level PGO profile, the __llvm_profile_raw_version variable,
which is used for marking instrumentation level, generated by frontend
would somehow conflict with the weak symbol provided by profiling
runtime.
In most of the cases, BFD linkers will pick profiling runtime's weak symbol
as the real definition and thus generate the incorrect instrumentation
level metadata in the final executables.
Moving __llvm_profile_raw_version into a separate file would make
linkers not seeing the weak symbol in the archive unless the frontend
doesn't generate one.
[1] https://reviews.llvm.org/D34797
Differential Revision: https://reviews.llvm.org/D83967
Extend the memop value profile buckets to be more flexible (could accommodate a
mix of individual values and ranges) and to cover more value ranges (from 11 to
22 buckets).
Disabled behind a flag (to be enabled separately) and the existing code to be
removed later.
atexit registered functions run earlier so `__attribute__((destructor))`
annotated functions cannot be tracked.
Set a priority of 100 (compatible with GCC 7 onwards) to track
destructors and destructors whose priorities are greater than 100.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=7970
Reviewed By: calixte, marco-c
Differential Revision: https://reviews.llvm.org/D82253
Extend the memop value profile buckets to be more flexible (could accommodate a
mix of individual values and ranges) and to cover more value ranges (from 11 to
22 buckets).
Disabled behind a flag (to be enabled separately) and the existing code to be
removed later.
Differential Revision: https://reviews.llvm.org/D81682
The !associated metadata may be attached to a global object declaration
with a single argument that references another global object. This
metadata prevents discarding of the global object in linker GC unless
the referenced object is also discarded.
Furthermore, 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. This is not possible today
because there's metadata to guide the linker. This approach is also used
by other instrumentations like sanitizers.
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
The !associated metadata may be attached to a global object declaration
with a single argument that references another global object. This
metadata prevents discarding of the global object in linker GC unless
the referenced object is also discarded.
Furthermore, 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. This is not possible today
because there's metadata to guide the linker. This approach is also used
by other instrumentations like sanitizers.
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
Nico Weber