The type of *Iter here is "const IndexedMemProfRecord &" as defined in
RecordLookupTrait. Assigning *Iter to a variable of type
"const IndexedMemProfRecord &" avoids a copy, reducing the cycle and
instruction counts by 1.8% and 0.2%, respectively, with
"llvm-profdata show" modified to deserialize all MemProfRecords.
Note that RecordLookupTrait has an internal copy of
IndexedMemProfRecord, so we don't have to worry about a dangling
reference to a temporary.
With this patch, we stop using on-disk hash tables for Frames and call
stacks. Instead, we'll write out all the Frames as a flat array while
maintaining mappings from FrameIds to the indexes into the array.
Then we serialize call stacks in terms of those indexes.
Likewise, we'll write out all the call stacks as another flat array
while maintaining mappings from CallStackIds to the indexes into the
call stack array. One minor difference from Frames is that the
indexes into the call stack array are not contiguous because call
stacks are variable-length objects.
Then we serialize IndexedMemProfRecords in terms of the indexes
into the call stack array.
Now, we describe each call stack with 32-bit indexes into the Frame
array (as opposed to the 64-bit FrameIds in Version 2). The use of
the smaller type cuts down the profile file size by about 40% relative
to Version 2. The departure from the on-disk hash tables contributes
a little bit to the savings, too.
For now, IndexedMemProfRecords refer to call stacks with 64-bit
indexes into the call stack array. As a follow-up, I'll change that
to uint32_t, including necessary updates to RecordWriterTrait.
This patch teaches the V3 format to serialize Frames, call stacks, and
IndexedMemProfRecords, in that order.
I'm planning to use linear IDs for Frames. That is, Frames will be
numbered 0, 1, 2, and so on in the order we serialize them. In turn,
we will seialize the call stacks in terms of those linear IDs.
Likewise, I'm planning to use linear IDs for call stacks and then
serialize IndexedMemProfRecords in terms of those linear IDs for call
stacks.
With the new order, we can successively free data structures as we
serialize them. That is, once we serialize Frames, we can free the
Frames' data proper and just retain mappings from FrameIds to linear
IDs. A similar story applies to call stacks.
This patch adds Version 3 for development purposes. For now, this
patch adds V3 as a copy of V2.
For the most part, this patch adds "case Version3:" wherever "case
Version2:" appears. One exception is writeMemProfV3, which is copied
from writeMemProfV2 but updated to write out memprof::Version3 to the
MemProf header. We'll incrementally modify writeMemProfV3 in
subsequent patches.
This patch refactors getMemProfRecord for readability while adding
consistency checks.
- This patch adds a switch statement on the MemProf version just like
most places dealing with MemProf serialization/deserialization.
- This patch adds asserts to ensure that the exact set of data
structures are available while ones we do not use are not present.
That is, getMemProfRecord no longer determines the version based on
the availability of MemProfCallStackTable.
Currently, we convert FrameId to Frame and CallStackId to a call stack
at several places. This patch unifies those into function objects --
FrameIdConverter and CallStackIdConverter.
The existing implementation of CallStackIdConverter, being removed in
this patch, handles both FrameId and CallStackId conversions. This
patch splits it into two phases for flexibility (but make them
composable) because some places only require the FrameId conversion.
This iteration fixes a problem uncovered with ubsan, where we were
dereferencing an uninitialized std::unique_ptr.
Currently, we convert FrameId to Frame and CallStackId to a call stack
at several places. This patch unifies those into function objects --
FrameIdConverter and CallStackIdConverter.
The existing implementation of CallStackIdConverter, being removed in
this patch, handles both FrameId and CallStackId conversions. This
patch splits it into two phases for flexibility (but make them
composable) because some places only require the FrameId conversion.
OnDiskIterableChainedHashTable::Create can default-contruct a trait
object for us. We don't need to construct one on our own unless we
need to customize something (like a version number).
Without this patch, a lot of details about the deserilization of the
MemProf data are exposed in IndexedInstrProfReader -- four
MemProf-related variables in IndexedInstrProfReader plus 90+ lines of
deserilization code within IndexedInstrProfReader::readHeader.
This patch encapsulates them into a separate class, exposing only
three methods, namely the default constructor, deserialize, and
getMemProfRecord.
This patch adds Version2 of the indexed MemProf format. The new
format comes with a hash table from CallStackId to actual call stacks
llvm::SmallVector<FrameId>. The rest of the format refers to call
stacks with CallStackId. This "values + references" model effectively
deduplicates call stacks. Without this patch, a large indexed memprof
file of mine shrinks from 4.4GB to 1.6GB, a 64% reduction.
This patch does not make Version2 generally available yet as I am
planning to make a few more changes to the format.
I'm currently developing a new version of the indexed memprof format
where we deduplicate call stacks in IndexedAllocationInfo::CallStack
and IndexedMemProfRecord::CallSites. We refer to call stacks with
integer IDs, namely CallStackId, just as we refer to Frame with
FrameId. The deduplication will cut down the profile file size by 80%
in a large memprof file of mine.
As a step toward the goal, this patch teaches
IndexedMemProfRecord::{serialize,deserialize} to speak Version2. A
subsequent patch will add Version2 support to llvm-profdata.
The essense of the patch is to replace the serialization of a call
stack, a vector of FrameIDs, with that of a CallStackId. That is:
const IndexedAllocationInfo &N = ...;
...
LE.write<uint64_t>(N.CallStack.size());
for (const FrameId &Id : N.CallStack)
LE.write<FrameId>(Id);
becomes:
LE.write<CallStackId>(N.CSId);
(The profile format change is split into a standalone change into https://github.com/llvm/llvm-project/pull/81691)
* For InstrFDO value profiling, implement instrumentation and lowering for virtual table address.
* This is controlled by `-enable-vtable-value-profiling` and off by default.
* When the option is on, raw profiles will carry serialized `VTableProfData` structs and compressed vtables as payloads.
* Implement profile reader and writer support
* Raw profile reader is used by `llvm-profdata` but not compiler. Raw profile reader will construct InstrProfSymtab with symbol names, and map profiled runtime address to vtable symbols.
* Indexed profile reader is used by `llvm-profdata` and compiler. When initialized, the reader stores a pointer to the beginning of in-memory compressed vtable names and the length of string. When used in `llvm-profdata`, reader decompress the string to show symbols of a profiled site. When used in compiler, string decompression doesn't
happen since IR is used to construct InstrProfSymtab.
* Indexed profile writer collects the list of vtable names, and stores that to index profiles.
* Text profile reader and writer support are added but mostly follow the implementation for indirect-call value type.
* `llvm-profdata show -show-vtables <args> <profile>` is implemented.
rfc in
https://discourse.llvm.org/t/rfc-dynamic-type-profiling-and-optimizations-in-llvm/74600#pick-instrumentation-points-and-instrument-runtime-types-7
This patch adds a version field to the MemProf section of the indexed
profile format, calling the new version "version 1". The existing
version is called "version 0".
The writer supports both versions via a command-line option:
llvm-profdata merge --memprof-version=1 ...
The reader supports both versions by automatically detecting the
version from the header.
There are two ways to create in-memory instances of
IndexedAllocationInfo -- deserialization of the raw MemProf data and
that of the indexed MemProf data.
With:
commit 74799f424063a2d751e0f9ea698db1f4efd0d8b2
Author: Kazu Hirata <kazu@google.com>
Date: Sat Mar 23 19:50:15 2024 -0700
we compute CallStackId for each call stack in IndexedAllocationInfo
while deserializing the raw MemProf data.
This patch does the same while deserilizing the indexed MemProf data.
As with the patch above, this patch does not add any use of
CallStackId yet.
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>
* 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>
* `getFunctionBitmap()` stores not `std::vector<uint8_t>` but
`BitVector`.
* `CounterMappingContext` holds `Bitmap` (instead of the ref of bytes)
* `Bitmap` and `BitmapIdx` are used instead of `evaluateBitmap()`.
FIXME: `InstrProfRecord` itself should handle `Bitmap` as `BitVector`.
Before this patch, when the field `NameRef` is generated in little-endian systems and read back in big-endian systems, the information gets dropped.
- The bug gets caught by a buildbot
https://lab.llvm.org/buildbot/#/builders/94/builds/17931. In the error message (pasted below),
two indirect call targets are not imported.
```
; IMPORTS-DAG: Import _Z7callee1v
^
<stdin>:1:1: note: scanning from here
main.ll: Import _Z11global_funcv from lib.cc
^
<stdin>:1:10: note: possible intended match here
main.ll: Import _Z11global_funcv from lib.cc
^
Input file: <stdin>
Check file:
/home/uweigand/sandbox/buildbot/clang-s390x-linux/llvm/llvm/test/Transforms/PGOProfile/thinlto_indirect_call_promotion.ll
-dump-input=help explains the following input dump.
Input was:
<<<<<<
1: main.ll: Import _Z11global_funcv from lib.cc
dag:34'0 X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match
found
dag:34'1 ? possible intended match
```
[This commit](b3999246b1 (diff-b196b796c5a396c7cdf93b347fe47e2b29b72d0b7dd0e2b88abb964d376ee50e)) gates the fix by flag and provide test data by creating big-endian profiles (rather than reading the little-endian data on a big-endian system that might require a VM).
- [This](b3999246b1 (diff-643176077ddbe537bd0a05d2a8a53bdff6339420a30e8511710bf232afdda8b9)) is a hexdump of little-endian profile data, and [this](b3999246b1 (diff-1736a3ee25dde02bba55d670df78988fdb227e5a85b94b8707cf182cf70b28f0)) is the big-endian version of it.
- The [README.md](b3999246b1 (diff-6717b6a385de3ae60ab3aec9638af2a43b55adaf6784b6f0393ebe1a6639438b)) shows the result of `llvm-profdata show -ic-targets` before and after the fix when the profile is in big-endian.
Simplify the compiler-rt test to make it more general for different
platforms, and use `*DAG` matchers for lines that may be emitted
out-of-order.
- The compiler-rt test passed on a Windows machine. Previously name
matchers don't work for MSVC mangling
(https://lab.llvm.org/buildbot/#/builders/127/builds/59907)
- `*DAG` matchers fixed the error in
https://lab.llvm.org/buildbot/#/builders/94/builds/17924
This is the second reland and fixed errors caught in first reland
(https://github.com/llvm/llvm-project/pull/75860)
**Original commit message**
Commit fe05193 (phab D156569), IRPGO names uses format
`[<filepath>;]<linkage-name>` while prior format is
`[<filepath>:<mangled-name>`. The format change would break the use case
demonstrated in (updated)
`llvm/test/Transforms/PGOProfile/thinlto_indirect_call_promotion.ll` and
`compiler-rt/test/profile/instrprof-thinlto-indirect-call-promotion.cpp`
This patch changes `GlobalValues::getGlobalIdentifer` to use the
semicolon.
To elaborate on the scenario how things break without this PR
1. IRPGO raw profiles stores (compressed) IRPGO names of functions in
one section, and per-function profile data in another section. The
[NameRef](fc715e4cd9/compiler-rt/include/profile/InstrProfData.inc (L72))
field in per-function profile data is the MD5 hash of IRPGO names.
2. When raw profiles are converted to indexed format profiles, the
profiled address is
[mapped](fc715e4cd9/llvm/lib/ProfileData/InstrProf.cpp (L876-L885))
to the MD5 hash of the callee.
3. In `pgo-instr-use` thin-lto prelink pipeline, MD5 hash of IRPGO names
will be
[annotated](fc715e4cd9/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp (L1707))
as value profiles, and used to import indirect-call-prom candidates. If
the annotated MD5 hash is computed from the new format while import uses
the prior format, the callee cannot be imported.
*
`compiler-rt/test/profile/instrprof-thinlto-indirect-call-promotion.cpp`
is added to have an end-to-end test.
* `llvm/test/Transforms/PGOProfile/thinlto_indirect_call_promotion.ll`
is updated to have better test coverage from another aspect (as runtime
tests are more sensitive to the environment and may be skipped by some
contributors)
Fixed build-bot failures caught by post-submit tests
1) Add the list of command line tools needed by new compiler-rt test into dependency.
2) Use `starts_with` to replace deprecated `startswith`.
**Original commit message**
Commit fe05193 (phab D156569), IRPGO names uses format
`[<filepath>;]<linkage-name>` while prior format is
`[<filepath>:<mangled-name>`. The format change would break the use case
demonstrated in (updated)
`llvm/test/Transforms/PGOProfile/thinlto_indirect_call_promotion.ll` and
`compiler-rt/test/profile/instrprof-thinlto-indirect-call-promotion.cpp`
This patch changes `GlobalValues::getGlobalIdentifer` to use the
semicolon.
To elaborate on the scenario how things break without this PR
1. IRPGO raw profiles stores (compressed) IRPGO names of functions in
one section, and per-function profile data in another section. The
[NameRef](fc715e4cd9/compiler-rt/include/profile/InstrProfData.inc (L72))
field in per-function profile data is the MD5 hash of IRPGO names.
2. When raw profiles are converted to indexed format profiles, the
profiled address is
[mapped](fc715e4cd9/llvm/lib/ProfileData/InstrProf.cpp (L876-L885))
to the MD5 hash of the callee.
3. In `pgo-instr-use` thin-lto prelink pipeline, MD5 hash of IRPGO names
will be
[annotated](fc715e4cd9/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp (L1707))
as value profiles, and used to import indirect-call-prom candidates. If
the annotated MD5 hash is computed from the new format while import uses
the prior format, the callee cannot be imported.
*
`compiler-rt/test/profile/instrprof-thinlto-indirect-call-promotion.cpp`
is added to have an end-to-end test.
* `llvm/test/Transforms/PGOProfile/thinlto_indirect_call_promotion.ll`
is updated to have better test coverage from another aspect (as runtime
tests are more sensitive to the environment and may be skipped by some
contributors)
Commit fe05193 (phab D156569), IRPGO names uses format
`[<filepath>;]<linkage-name>` while prior format is
`[<filepath>:<mangled-name>`. The format change would break the use case
demonstrated in (updated)
`llvm/test/Transforms/PGOProfile/thinlto_indirect_call_promotion.ll` and
`compiler-rt/test/profile/instrprof-thinlto-indirect-call-promotion.cpp`
This patch changes `GlobalValues::getGlobalIdentifer` to use the
semicolon.
To elaborate on the scenario how things break without this PR
1. IRPGO raw profiles stores (compressed) IRPGO names of functions in
one section, and per-function profile data in another section. The
[NameRef](fc715e4cd9/compiler-rt/include/profile/InstrProfData.inc (L72))
field in per-function profile data is the MD5 hash of IRPGO names.
2. When raw profiles are converted to indexed format profiles, the
profiled address is
[mapped](fc715e4cd9/llvm/lib/ProfileData/InstrProf.cpp (L876-L885))
to the MD5 hash of the callee.
3. In `pgo-instr-use` thin-lto prelink pipeline, MD5 hash of IRPGO names
will be
[annotated](fc715e4cd9/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp (L1707))
as value profiles, and used to import indirect-call-prom candidates. If
the annotated MD5 hash is computed from the new format while import uses
the prior format, the callee cannot be imported.
*`compiler-rt/test/profile/instrprof-thinlto-indirect-call-promotion.cpp`
is added to have an end-to-end test.
* `llvm/test/Transforms/PGOProfile/thinlto_indirect_call_promotion.ll`
is updated to have better test coverage from another aspect (as runtime
tests are more sensitive to the environment and may be skipped by some
contributors)
## Motivation
Since we don't need the metadata sections at runtime, we can somehow
offload them from memory at runtime. Initially, I explored [debug info
correlation](https://discourse.llvm.org/t/instrprofiling-lightweight-instrumentation/59113),
which is used for PGO with value profiling disabled. However, it
currently only works with DWARF and it's be hard to add such artificial
debug info for every function in to CodeView which is used on Windows.
So, offloading profile metadata sections at runtime seems to be a
platform independent option.
## Design
The idea is to use new section names for profile name and data sections
and mark them as metadata sections. Under this mode, the new sections
are non-SHF_ALLOC in ELF. So, they are not loaded into memory at runtime
and can be stripped away as a post-linking step. After the process
exits, the generated raw profiles will contains only headers + counters.
llvm-profdata can be used correlate raw profiles with the unstripped
binary to generate indexed profile.
## Data
For chromium base_unittests with code coverage on linux, the binary size
overhead due to instrumentation reduced from 64M to 38.8M (39.4%) and
the raw profile files size reduce from 128M to 68M (46.9%)
```
$ bloaty out/cov/base_unittests.stripped -- out/no-cov/base_unittests.stripped
FILE SIZE VM SIZE
-------------- --------------
+121% +30.4Mi +121% +30.4Mi .text
[NEW] +14.6Mi [NEW] +14.6Mi __llvm_prf_data
[NEW] +10.6Mi [NEW] +10.6Mi __llvm_prf_names
[NEW] +5.86Mi [NEW] +5.86Mi __llvm_prf_cnts
+95% +1.75Mi +95% +1.75Mi .eh_frame
+108% +400Ki +108% +400Ki .eh_frame_hdr
+9.5% +211Ki +9.5% +211Ki .rela.dyn
+9.2% +95.0Ki +9.2% +95.0Ki .data.rel.ro
+5.0% +87.3Ki +5.0% +87.3Ki .rodata
[ = ] 0 +13% +47.0Ki .bss
+40% +1.78Ki +40% +1.78Ki .got
+12% +1.49Ki +12% +1.49Ki .gcc_except_table
[ = ] 0 +65% +1.23Ki .relro_padding
+62% +1.20Ki [ = ] 0 [Unmapped]
+13% +448 +19% +448 .init_array
+8.8% +192 [ = ] 0 [ELF Section Headers]
+0.0% +136 +0.0% +80 [7 Others]
+0.1% +96 +0.1% +96 .dynsym
+1.2% +96 +1.2% +96 .rela.plt
+1.5% +80 +1.2% +64 .plt
[ = ] 0 -99.2% -3.68Ki [LOAD #5 [RW]]
+195% +64.0Mi +194% +64.0Mi TOTAL
$ bloaty out/cov-cor/base_unittests.stripped -- out/no-cov/base_unittests.stripped
FILE SIZE VM SIZE
-------------- --------------
+121% +30.4Mi +121% +30.4Mi .text
[NEW] +5.86Mi [NEW] +5.86Mi __llvm_prf_cnts
+95% +1.75Mi +95% +1.75Mi .eh_frame
+108% +400Ki +108% +400Ki .eh_frame_hdr
+9.5% +211Ki +9.5% +211Ki .rela.dyn
+9.2% +95.0Ki +9.2% +95.0Ki .data.rel.ro
+5.0% +87.3Ki +5.0% +87.3Ki .rodata
[ = ] 0 +13% +47.0Ki .bss
+40% +1.78Ki +40% +1.78Ki .got
+12% +1.49Ki +12% +1.49Ki .gcc_except_table
+13% +448 +19% +448 .init_array
+0.1% +96 +0.1% +96 .dynsym
+1.2% +96 +1.2% +96 .rela.plt
+1.2% +64 +1.2% +64 .plt
+2.9% +64 [ = ] 0 [ELF Section Headers]
+0.0% +40 +0.0% +40 .data
+1.2% +32 +1.2% +32 .got.plt
+0.0% +24 +0.0% +8 [5 Others]
[ = ] 0 -22.9% -872 [LOAD #5 [RW]]
-74.5% -1.44Ki [ = ] 0 [Unmapped]
[ = ] 0 -76.5% -1.45Ki .relro_padding
+118% +38.8Mi +117% +38.8Mi TOTAL
```
A few things to note:
1. llvm-profdata doesn't support filter raw profiles by binary id yet,
so when a raw profile doesn't belongs to the binary being digested by
llvm-profdata, merging will fail. Once this is implemented,
llvm-profdata should be able to only merge raw profiles with the same
binary id as the binary and discard the rest (with mismatched/missing
binary id). The workflow I have in mind is to have scripts invoke
llvm-profdata to get all binary ids for all raw profiles, and
selectively choose the raw pnrofiles with matching binary id and the
binary to llvm-profdata for merging.
2. Note: In COFF, currently they are still loaded into memory but not
used. I didn't do it in this patch because I noticed that `.lcovmap` and
`.lcovfunc` are loaded into memory. A separate patch will address it.
3. This should works with PGO when value profiling is disabled as debug
info correlation currently doing, though I haven't tested this yet.
This patch replaces uses of StringRef::{starts,ends}with with
StringRef::{starts,ends}_with for consistency with
std::{string,string_view}::{starts,ends}_with in C++20.
I'm planning to deprecate and eventually remove
StringRef::{starts,ends}with.
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
Note that llvm::support::endianness has been renamed to
llvm::endianness while becoming an enum class. This patch replaces
{big,little,native} with llvm::endianness::{big,little,native}.
This patch completes the migration to llvm::endianness and
llvm::endianness::{big,little,native}. I'll post a separate patch to
remove the migration helpers in llvm/Support/Endian.h:
using endianness = llvm::endianness;
constexpr llvm::endianness big = llvm::endianness::big;
constexpr llvm::endianness little = llvm::endianness::little;
constexpr llvm::endianness native = llvm::endianness::native;
Note that llvm::support::endianness has been renamed to
llvm::endianness while becoming an enum class as opposed to an enum.
This patch replaces llvm::support::{big,little,native} with
llvm::endianness::{big,little,native}.
Now that llvm::support::endianness has been renamed to
llvm::endianness, we can use the shorter form. This patch replaces
llvm::support::endianness with llvm::endianness.
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 a50486fd736ab2fe03fcacaf8b98876db77217a7.
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
Prior to this diff, names in the `__llvm_prf_names` section had the format `[<filepath>:]<function-name>`, e.g., `main.cpp:foo`, `bar`. `<filepath>` is used to discriminate between possibly identical function names when linkage is local and `<function-name>` simply comes from `F.getName()`. This has two problems:
* `:` is commonly found in Objective-C functions so that names like `main.mm:-[C foo::]` and `-[C bar::]` are difficult to parse
* `<function-name>` might be different from the linkage name, so it cannot be used to pass a function order to the linker via `-symbol-ordering-file` or `-order_file` (see https://discourse.llvm.org/t/rfc-temporal-profiling-extension-for-irpgo/68068)
Instead, this diff changes the format to `[<filepath>;]<linkage-name>`, e.g., `main.cpp;_foo`, `_bar`. The hope is that `;` won't realistically be found in either `<filepath>` or `<linkage-name>`.
To prevent invalidating all prior IRPGO profiles, we also lookup the prior name format when a record is not found (see `InstrProfSymtab::create()`, `readMemprof()`, and `getInstrProfRecord()`). It seems that Swift and Clang FE-PGO rely on the original `getPGOFuncName()`, so we cannot simply replace it.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D156569
When a user uses a mismatched clang + llvm-profdata, they didn't get a very
informative error message. It would just say "unsupported version".
As a result, users are often confused as to what they are supposed to do and
tend to assume that it's a bug in the profiling runtime.
This patch improves the error message by:
- Adding a new class of error (`raw_profile_version_mismatch`) to make it clear
that, specifically, the *raw profile* version is unsupported because of a
tool mismatch.
- Adding an error message that tells the user which raw profile version was
encountered, which version was expected, and instructs them to align their
tool versions.
To support this, this patch also updates `InstrProfError::take` to also
propagate the optional error message.
Differential Revision: https://reviews.llvm.org/D149361
