New change on top of [reviewed
patch](https://github.com/llvm/llvm-project/pull/81691) are [in commits
after this
one](d0757f46b3).
Previous commits are restored from the remote branch with timestamps.
1. Fix build breakage for non-ELF platforms, by defining the missing
functions {`__llvm_profile_begin_vtables`, `__llvm_profile_end_vtables`,
`__llvm_profile_begin_vtabnames `, `__llvm_profile_end_vtabnames`}
everywhere.
* Tested on mac laptop (for darwins) and Windows. Specifically,
functions in `InstrProfilingPlatformWindows.c` returns `NULL` to make it
more explicit that type prof isn't supported; see comments for the
reason.
* For the rest (AIX, other), mostly follow existing examples (like this
[one](f95b2f1acf))
2. Rename `__llvm_prf_vtabnames` -> `__llvm_prf_vns` for shorter section
name, and make returned pointers
[const](a825d2a4ec (diff-4de780ce726d76b7abc9d3353aef95013e7b21e7bda01be8940cc6574fb0b5ffR120-R121))
**Original Description**
* Raw profile format
- Header: records the byte size of compressed vtable names, and the
number of profiled vtable entries (call it `VTableProfData`). Header
also records padded bytes of each section.
- Payload: adds a section for compressed vtable names, and a section to
store `VTableProfData`. Both sections are padded so the size is a
multiple of 8.
* Indexed profile format
- Header: records the byte offset of compressed vtable names.
- Payload: adds a section to store compressed vtable names. This section
is used by `llvm-profdata` to show the list of vtables profiled for an
instrumented site.
[The originally reviewed
patch](https://github.com/llvm/llvm-project/pull/66825) will have
profile reader/write change and llvm-profdata change.
- To ensure this PR has all the necessary profile format change along
with profile version bump, created a copy of the originally reviewed
patch in https://github.com/llvm/llvm-project/pull/80761. The copy
doesn't have profile format change, but it has the set of tests which
covers type profile generation, profile read and profile merge. Tests
pass there.
rfc in
https://discourse.llvm.org/t/rfc-dynamic-type-profiling-and-optimizations-in-llvm/74600
---------
Co-authored-by: modiking <modiking213@gmail.com>
This patch inserts 1-byte counters instead of an 8-byte counters into
llvm profiles for source-based code coverage. The origial idea was
proposed as block-cov for PGO, and this patch repurposes that idea for
coverage: https://groups.google.com/g/llvm-dev/c/r03Z6JoN7d4
The current 8-byte counters mechanism add counters to minimal regions,
and infer the counters in the remaining regions via adding or
subtracting counters. For example, it infers the counter in the if.else
region by subtracting the counters between if.entry and if.then regions
in an if statement. Whenever there is a control-flow merge, it adds the
counters from all the incoming regions. However, we are not going to be
able to infer counters by subtracting two execution counts when using
single-byte counters. Therefore, this patch conservatively inserts
additional counters for the cases where we need to add or subtract
counters.
RFC:
https://discourse.llvm.org/t/rfc-single-byte-counters-for-source-based-code-coverage/75685
* Raw profile format
- Header: records the byte size of compressed vtable names, and the
number of profiled vtable entries (call it `VTableProfData`). Header
also records padded bytes of each section.
- Payload: adds a section for compressed vtable names, and a section to
store `VTableProfData`. Both sections are padded so the size is a
multiple of 8.
* Indexed profile format
- Header: records the byte offset of compressed vtable names.
- Payload: adds a section to store compressed vtable names. This section
is used by `llvm-profdata` to show the list of vtables profiled for an
instrumented site.
[The originally reviewed
patch](https://github.com/llvm/llvm-project/pull/66825) will have
profile reader/write change and llvm-profdata change.
- To ensure this PR has all the necessary profile format change along
with profile version bump, created a copy of the originally reviewed
patch in https://github.com/llvm/llvm-project/pull/80761. The copy
doesn't have profile format change, but it has the set of tests which
covers type profile generation, profile read and profile merge. Tests
pass there.
rfc in
https://discourse.llvm.org/t/rfc-dynamic-type-profiling-and-optimizations-in-llvm/74600
---------
Co-authored-by: modiking <modiking213@gmail.com>
This PR exposes four PGO functions
- `__llvm_profile_set_filename`
- `__llvm_profile_reset_counters`,
- `__llvm_profile_dump`
- `__llvm_orderfile_dump`
to user programs through the new header `instr_prof_interface.h` under
`compiler-rt/include/profile`. This way, the user can include the header
`profile/instr_prof_interface.h` to introduce these four names to their
programs.
Additionally, this PR defines macro `__LLVM_INSTR_PROFILE_GENERATE` when
the program is compiled with profile generation, and defines macro
`__LLVM_INSTR_PROFILE_USE` when the program is compiled with profile
use. `__LLVM_INSTR_PROFILE_GENERATE` together with
`instr_prof_interface.h` define the PGO functions only when the program
is compiled with profile generation. When profile generation is off,
these PGO functions are defined away and leave no trace in the user's
program.
Background:
https://discourse.llvm.org/t/pgo-are-the-llvm-profile-functions-stable-c-apis-across-llvm-releases/75832
When LLVM_PROFILE_FILE is set incorrectly (e.g. multiple %c) and it
falls back to use `default.profraw` name, but continuous mode is still
set. This might cause signal bus in the following scenario.
LLVM_PROFILE_FILE is set incorrectly (with "%c%c") for process A and B.
Suppose A starts first and falls back to use `default.profraw` and
mmaped its file content to memory. Later B starts and also falls back to
use `default.profraw`, but it will truncate the file because online
merging is disable when reseting to `default.profraw`. When A tries to
update counter via mmaped memory, signal bus will occur.
This fixes it by disabling continuous mode when reset to
default.profraw.
Part 1 of 3. This includes the LLVM back-end processing and profile
reading/writing components. compiler-rt changes are included.
Differential Revision: https://reviews.llvm.org/D138846
This seems to cause Clang to crash, see comments on the code review. Reverting
until the problem can be investigated.
> Part 1 of 3. This includes the LLVM back-end processing and profile
> reading/writing components. compiler-rt changes are included.
>
> Differential Revision: https://reviews.llvm.org/D138846
This reverts commit a50486fd73.
Part 1 of 3. This includes the LLVM back-end processing and profile
reading/writing components. compiler-rt changes are included.
Differential Revision: https://reviews.llvm.org/D138846
Existing code tended to assume that counters had type `uint64_t` and
computed size from the number of counters. Fix this code to directly
compute the counters size in number of bytes where possible. When the
number of counters is needed, use `__llvm_profile_counter_entry_size()`
or `getCounterTypeSize()`. In a later diff these functions will depend
on the profile mode.
Change the meaning of `DataSize` and `CountersSize` to make them more clear.
* `DataSize` (`CountersSize`) - the size of the data (counter) section in bytes.
* `NumData` (`NumCounters`) - the number of data (counter) entries.
Reviewed By: kyulee
Differential Revision: https://reviews.llvm.org/D116179
Since libclang_rt.profile is added later in the command line, a
definition of __llvm_profile_raw_version is not included if it is
provided from an earlier object, e.g. from a shared dependency.
This causes an extra dependence edge where if libA.so depends on libB.so
and both are coverage-instrumented, libA.so uses libB.so's definition of
__llvm_profile_raw_version. This leads to a runtime link failure if the
libB.so available at runtime does not provide this symbol (but provides
the other dependent symbols). Such a scenario can occur in Android's
mainline modules.
E.g.:
ld -o libB.so libclang_rt.profile-x86_64.a
ld -o libA.so -l B libclang_rt.profile-x86_64.a
libB.so has a global definition of __llvm_profile_raw_version. libA.so
uses libB.so's definition of __llvm_profile_raw_version. At runtime,
libB.so may not be coverage-instrumented (i.e. not export
__llvm_profile_raw_version) so runtime linking of libA.so will fail.
Marking this symbol as hidden forces each binary to use the definition
of __llvm_profile_raw_version from libclang_rt.profile. The visiblity
is unchanged for Apple platforms where its presence is checked by the
TAPI tool.
Reviewed By: MaskRay, phosek, davidxl
Differential Revision: https://reviews.llvm.org/D111759
Hide __llvm_profile_raw_version so as not to resolve reference from a
dependent shared object. Since libclang_rt.profile is added later in
the command line, a definition of __llvm_profile_raw_version is not
included if it is provided from an earlier object, e.g. from a shared
dependency.
This causes an extra dependence edge where if libA.so depends on libB.so
and both are coverage-instrumented, libA.so uses libB.so's definition of
__llvm_profile_raw_version. This leads to a runtime link failure if the
libB.so available at runtime does not provide this symbol (but provides
the other dependent symbols). Such a scenario can occur in Android's
mainline modules.
E.g.:
ld -o libB.so libclang_rt.profile-x86_64.a
ld -o libA.so -l B libclang_rt.profile-x86_64.a
libB.so has a global definition of __llvm_profile_raw_version. libA.so
uses libB.so's definition of __llvm_profile_raw_version. At runtime,
libB.so may not be coverage-instrumented (i.e. not export
__llvm_profile_raw_version) so runtime linking of libA.so will fail.
Marking this symbol as hidden forces each binary to use the definition
of __llvm_profile_raw_version from libclang_rt.profile.
Differential Revision: https://reviews.llvm.org/D111759
Replace D107203, because __llvm_profile_set_file_object is usually used when the
process doesn't have permission to open/create file. That patch trying to copy
from old profile to new profile contradicts with the usage.
Differential Revision: https://reviews.llvm.org/D108242
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 in which case the symbol selected
by the linker is going to depend on the order of inputs which can be
fragile.
This change replaces the use of weak definition inside the runtime with
a weak alias. We place the compiler generated symbol inside a COMDAT
group so dead definition can be garbage collected by the linker.
We also disable the use of runtime counter relocation on Darwin since
Mach-O doesn't support weak external references, but Darwin already uses
a different continous mode that relies on overmapping so runtime counter
relocation isn't needed there.
Differential Revision: https://reviews.llvm.org/D105176
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
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
On Fuchsia, we always use the continuous mode with runtime counter
relocation, so there's no need for atexit hook or support for dumping
the profile manually.
Differential Revision: https://reviews.llvm.org/D76556
This is an alternative to the continous mode that was implemented in
D68351. This mode relies on padding and the ability to mmap a file over
the existing mapping which is generally only available on POSIX systems
and isn't suitable for other platforms.
This change instead introduces the ability to relocate counters at
runtime using a level of indirection. On every counter access, we add a
bias to the counter address. This bias is stored in a symbol that's
provided by the profile runtime and is initially set to zero, meaning no
relocation. The runtime can mmap the profile into memory at abitrary
location, and set bias to the offset between the original and the new
counter location, at which point every subsequent counter access will be
to the new location, which allows updating profile directly akin to the
continous mode.
The advantage of this implementation is that doesn't require any special
OS support. The disadvantage is the extra overhead due to additional
instructions required for each counter access (overhead both in terms of
binary size and performance) plus duplication of counters (i.e. one copy
in the binary itself and another copy that's mmapped).
Differential Revision: https://reviews.llvm.org/D69740
This header fragment is useful on its own for any consumer that wants
to use custom instruction profile runtime with the LLVM instrumentation.
The concrete use case is in Fuchsia's kernel where we want to use
instruction profile instrumentation, but we cannot use the compiler-rt
runtime because it's not designed for use in the kernel environment.
This change allows installing this header as part of compiler-rt.
Differential Revision: https://reviews.llvm.org/D64532
This header fragment is useful on its own for any consumer that wants
to use custom instruction profile runtime with the LLVM instrumentation.
The concrete use case is in Fuchsia's kernel where we want to use
instruction profile instrumentation, but we cannot use the compiler-rt
runtime because it's not designed for use in the kernel environment.
This change allows installing this header as part of compiler-rt.
Differential Revision: https://reviews.llvm.org/D64532
Add support for continuously syncing profile counter updates to a file.
The motivation for this is that programs do not always exit cleanly. On
iOS, for example, programs are usually killed via a signal from the OS.
Running atexit() handlers after catching a signal is unreliable, so some
method for progressively writing out profile data is necessary.
The approach taken here is to mmap() the `__llvm_prf_cnts` section onto
a raw profile. To do this, the linker must page-align the counter and
data sections, and the runtime must ensure that counters are mapped to a
page-aligned offset within a raw profile.
Continuous mode is (for the moment) incompatible with the online merging
mode. This limitation is lifted in https://reviews.llvm.org/D69586.
Continuous mode is also (for the moment) incompatible with value
profiling, as I'm not sure whether there is interest in this and the
implementation may be tricky.
As I have not been able to test extensively on non-Darwin platforms,
only Darwin support is included for the moment. However, continuous mode
may "just work" without modification on Linux and some UNIX-likes. AIUI
the default value for the GNU linker's `--section-alignment` flag is set
to the page size on many systems. This appears to be true for LLD as
well, as its `no_nmagic` option is on by default. Continuous mode will
not "just work" on Fuchsia or Windows, as it's not possible to mmap() a
section on these platforms. There is a proposal to add a layer of
indirection to the profile instrumentation to support these platforms.
rdar://54210980
Differential Revision: https://reviews.llvm.org/D68351
When the %m filename pattern is used, the filename is unique to each
image, so the cached value is wrong.
It struck me that the full filename isn't something that's recomputed
often, so perhaps it doesn't need to be cached at all. David Li pointed
out we can go further and just hide lprofCurFilename. This may regress
workflows that depend on using the set-filename API to change filenames
across all loaded DSOs, but this is expected to be very rare.
rdar://55137071
Differential Revision: https://reviews.llvm.org/D69137
llvm-svn: 375301
Summary:
User code can open a file on its own and pass it to the runtime, rather than
specifying a name and having the runtime open the file. This supports the use
case where a process cannot open a file on its own but can receive a file
descriptor from another process.
Relanding https://reviews.llvm.org/D62541. The original revision unlocked
the file before calling flush, this revision fixes that.
Reviewers: Dor1s, davidxl
Reviewed By: Dor1s
Subscribers: #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D63581
llvm-svn: 364231
This caused instrumented Clang to become crashy. See llvm-commits thread
for repro steps.
This also reverts follow-up r362716 which added test cases.
> Author: Sajjad Mirza
>
> Differential Revision: http://reviews.llvm.org/D62541
llvm-svn: 363134
r355343 was landed and was reverted in r355363 due to build breakage.
This patch adds Linux/Windows support on top of r355343.
In this patch, Darwin should be working with testing case. Linux should be working,
I will enable the testing case in a follwup diff. Windows/Other should be building.
Correct implementation for Other platforms will be added.
Thanks David for reviewing the original diff, helping me with issues on Linux, and
giving suggestions for adding support for Other platforms.
llvm-svn: 355701
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
Summary:
Add __llvm_profile_get_filename interface to get the profile filename,
which can be used for identifying which profile file belongs to an app
when multiple binaries are instrumented and dumping profiles into the
same directory. The filename includes the path.
Reviewers: davidxl
Subscribers: delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D49529
llvm-svn: 337482
This patch fixes the following issues:
(1) The strong definition of the merge hook function was not working which
breaks the online value profile merging. This patch removes the weak
attribute of VPMergeHook and assigns the value dynamically.
(2) Truncate the proifle file so that we don't have garbage data at the end of
the file.
(3) Add new __llvm_profile_instrument_target_value() interface to do the value
profile update in batch. This is needed as the original incremental by 1
in __llvm_profile_instrument_target() is too slow for online merge.
Differential Revision: https://reviews.llvm.org/D44847
llvm-svn: 328987
The buildbots have shown that -Wstrict-prototypes behaves differently in GCC
and Clang so we should keep it disabled until Clang follows GCC's behaviour
llvm-svn: 312246
Clang 5 supports -Wstrict-prototypes. We should use it to catch any C
declarations that declare a non-prototype function.
rdar://33705313
Differential Revision: https://reviews.llvm.org/D36669
llvm-svn: 312240
The API is intended to be used by user to do fine
grained (per-region) control of profile dumping.
Differential Revision: http://reviews.llvm.org/D23106
llvm-svn: 278092
