Commit Graph

592 Commits

Author SHA1 Message Date
Fangrui Song 4d7b194543 [llvm-cov gcov] Refactor counting and reporting
The current organization of FileInfo and its referenced utility functions of
(GCOVFile, GCOVFunction, GCOVBlock) is messy. Some members of FileInfo are just
copied from GCOVFile. FileInfo::print (.gcov output and --intermediate output)
is interleaved with branch statistics and computation of line execution counts.
--intermediate has to do redundant .gcov output to gather branch statistics.

This patch deletes lots of code and introduces a clearer work flow:

```
fn collectFunction
  for each block b
    for each line lineNum
      let line be LineInfo of the file on lineNum
      line.exists = 1
      increment function's lines & linesExec if necessary
      increment line.count
      line.blocks.push_back(&b)

fn collectSourceLine
  compute cycle counts
  count = incoming_counts + cycle_counts
  if line.exists
    ++summary->lines
    if line.count
      ++summary->linesExec

fn collectSource
  for each line
    call collectSourceLine

fn main
  for each function
    call collectFunction
    print function summary
  for each source file
    call collectSource
    print file summary
    annotate the source file with line execution counts
  if -i
    print intermediate file
```

The output order of functions and files now follows the original order in
.gcno files.
2020-09-13 23:00:59 -07:00
Fangrui Song b2c32c90ba [llvm-cov gcov] Add -r (--relative-only) && -s (--source-prefix)
gcov 4.7 introduced the two options.
https://sourceware.org/pipermail/gcc-patches/2011-November/328782.html

-r only dumps files with relative paths or absolute paths with the prefix
specified by -s. The two options are useful filtering out system header files.
2020-09-13 14:54:20 -07:00
Fangrui Song 8cf1ac97ce [llvm-cov gcov] Improve accuracy when some edges are not measured
Also guard against infinite recursion if GCOV_ARC_ON_TREE edges contain a cycle.
2020-09-12 22:33:41 -07:00
Fangrui Song 6a9a0bfc33 [llvm-cov gcov] Simply computation of line counts and exit block counter 2020-09-08 23:15:37 -07:00
Fangrui Song b9d086693b [llvm-cov gcov] Compute unmeasured arc counts by Kirchhoff's circuit law
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.
2020-09-08 18:45:11 -07:00
Wei Mi c67ccf5faf [SampleFDO] Enhance profile remapping support for searching inline instance
and indirect call promotion candidate.

Profile remapping is a feature to match a function in the module with its
profile in sample profile if the function name and the name in profile look
different but are equivalent using given remapping rules. This is a useful
feature to keep the performance stable by specifying some remapping rules
when sampleFDO targets are going through some large scale function signature
change.

However, currently profile remapping support is only valid for outline
function profile in SampleFDO. It cannot match a callee with an inline
instance profile if they have different but equivalent names. We found
that without the support for inline instance profile, remapping is less
effective for some large scale change.

To add that support, before any remapping lookup happens, all the names
in the profile will be inserted into remapper and the Key to the name
mapping will be recorded in a map called NameMap in the remapper. During
name lookup, a Key will be returned for the given name and it will be used
to extract an equivalent name in the profile from NameMap. So with the help
of the NameMap, we can translate any given name to an equivalent name in
the profile if it exists. Whenever we try to match a name in the module to
a name in the profile, we will try the match with the original name first,
and if it doesn't match, we will use the equivalent name got from remapper
to try the match for another time. In this way, the patch can enhance the
profile remapping support for searching inline instance and searching
indirect call promotion candidate.

In a planned large scale change of int64 type (long long) to int64_t (long),
we found the performance of a google internal benchmark degraded by 2% if
nothing was done. If existing profile remapping was enabled, the performance
degradation dropped to 1.2%. If the profile remapping with the current patch
was enabled, the performance degradation further dropped to 0.14% (Note the
experiment was done before searching indirect call promotion candidate was
added. We hope with the remapping support of searching indirect call promotion
candidate, the degradation can drop to 0% in the end. It will be evaluated
post commit).

Differential Revision: https://reviews.llvm.org/D86332
2020-08-26 11:07:35 -07:00
Zequan Wu e3df947175 [llvm-cov] reset executation count to 0 after wrapped segment
Fix the bug: https://bugs.llvm.org/show_bug.cgi?id=36979. It also fixes this bug: https://bugs.llvm.org/show_bug.cgi?id=35404, which I think is caused by the same problem.

Differential Revision: https://reviews.llvm.org/D85036
2020-08-04 18:38:44 -07:00
Hiroshi Yamauchi f78f509c75 [PGO] Extend the value profile buckets for mem op sizes.
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
2020-08-03 11:04:32 -07:00
Wei Mi a23f62343c Supplement instr profile with sample profile.
PGO profile is usually more precise than sample profile. However, PGO profile
needs to be collected from loadtest and loadtest may not be representative
enough to the production workload. Sample profile collected from production
can be used as a supplement -- for functions cold in loadtest but warm/hot
in production, we can scale up the related function in PGO profile if the
function is warm or hot in sample profile.

The implementation contains changes in compiler side and llvm-profdata side.
Given an instr profile and a sample profile, for a function cold in PGO
profile but warm/hot in sample profile, llvm-profdata will either mark
all the counters in the profile to be -1 or scale up the max count in the
function to be above hot threshold, depending on the zero counter ratio in
the profile. The assumption is if there are too many counters being zero
in the function profile, the profile is more likely to cause harm than good,
then llvm-profdata will mark all the counters to be -1 indicating the
function is hot but the profile is unaccountable. In compiler side, if a
function profile with all -1 counters is seen, the function entry count will
be set to be above hot threshold but its internal profile will be dropped.

In the long run, it may be useful to let compiler support using PGO profile
and sample profile at the same time, but that requires more careful design
and more substantial changes to make two profiles work seamlessly. The patch
here serves as a simple intermediate solution.

Differential Revision: https://reviews.llvm.org/D81981
2020-07-27 20:17:40 -07:00
Fangrui Song 27650ec554 Revert D81682 "[PGO] Extend the value profile buckets for mem op sizes."
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>
```
2020-07-22 16:08:25 -07:00
Rong Xu 50da55a585 [PGO] Supporting code for always instrumenting entry block
This patch includes the supporting code that enables always
instrumenting the function entry block by default.

This patch will NOT the default behavior.

It adds a variant bit in the profile version, adds new directives in
text profile format, and changes llvm-profdata tool accordingly.

This patch is a split of D83024 (https://reviews.llvm.org/D83024)
Many test changes from D83024 are also included.

Differential Revision: https://reviews.llvm.org/D84261
2020-07-22 15:01:53 -07:00
Fangrui Song 2e74b6d80f [llvm-cov gcov] Don't require NUL terminator when reading files
.gcno, .gcda and source files can be modified while we are reading them. If the
concurrent modification of a file being read nullifies the NUL terminator
assumption, llvm-cov can trip over an assertion failure in MemoryBuffer::init.
This is not so rare - the source files can be in an editor and .gcda can be
written by an running process (if the process forks, when .gcda gets written is
probably more unpredictable).

There is no accompanying test because an assertion failure requires data
races with some involved setting.
2020-07-19 00:31:52 -07:00
Hiroshi Yamauchi 4a539faf74 [PGO] Extend the value profile buckets for mem op sizes.
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.
2020-07-15 10:26:15 -07:00
Wei Mi e296e9dfd6 [NFC] Change getEntryForPercentile to be a static function in ProfileSummaryBuilder.
Change file static function getEntryForPercentile to be a static member function
in ProfileSummaryBuilder so it can be used by other files.

Differential Revision: https://reviews.llvm.org/D83439
2020-07-09 16:38:19 -07:00
Hiroshi Yamauchi 9878996c70 Revert "[PGO] Extend the value profile buckets for mem op sizes."
This reverts commit 63a89693f0.

Due to a build failure like http://lab.llvm.org:8011/builders/sanitizer-windows/builds/65386/steps/annotate/logs/stdio
2020-06-25 11:13:49 -07:00
Hiroshi Yamauchi 63a89693f0 [PGO] Extend the value profile buckets for mem op sizes.
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
2020-06-25 10:22:56 -07:00
Fangrui Song c8b082a3ab [llvm-cov gcov] Support clang<11 fake 4.2 format
Test cases are restored from a3bed4bd37
2020-06-17 10:17:15 -07:00
Fangrui Song 7f7cb79b57 [llvm-cov gcov] Don't suppress .gcov output if .gcda is corrupted
If .gcda is corrupted, gcov continues to produce a .gcov and just
assumes execution counts are zeros. This is reasonable, because the
program can corrupt its .gcda output. The code path should be similar to
the code path without .gcda.
2020-06-16 14:55:38 -07:00
Fangrui Song def2156389 [gcov] Add -i --intermediate-format
Between gcov 4.9~8, `gcov -i $file` prints coverage information to
$file.gcov in an intermediate text format (single file, instead of
$source.gcov for each source file).

lcov newer than 2019-05-24 detects -i support and uses it to increase
processing speed.  gcov 9 (GCC r265587) removed --intermediate-format
and -i was changed to mean --json-format. However, we consider this
format still useful and support it. geninfo (part of lcov) supports this
format even if we announce that we are compatible with gcov 9.0.0
2020-06-16 14:14:28 -07:00
Fangrui Song 4cd7ba7eca [gcov] Refactor llvm-cov gcov and add SourceInfo 2020-06-16 14:14:26 -07:00
Fangrui Song e664d0543f [gcov] Improve tests and lower the minimum supported version to gcov 3.4
global-ctor.ll no longer checks what it intended to check
(@_GLOBAL__sub_I_global-ctor.ll needs a !dbg to work).
Rewrite it.

gcov 3.4 and gcov 4.2 use the same format, thus we can lower the version
requirement to 3.4
2020-06-06 23:11:32 -07:00
Fangrui Song 1a2d4bf34e [gcov] Don't error 'unexpected end of memory buffe' 2020-06-03 22:05:15 -07:00
Fangrui Song 904b971aac [gcov] Make `Creating 'filename'` compatible with gcov
And clean up llvm-cov.test a bit
2020-06-03 21:48:01 -07:00
Fangrui Song 01899bb4e4 [gcov] Improve .gcno compatibility with gcov and use DataExtractor
llvm-cov.test and many Inputs/test* files contain wrong tests.
This patch rewrites a large portion of these files.
The pre-canned .gcno & .gcda are replaced by binaries produced by
clang --coverage (compatible with gcov 4.8~7)
(after some GCDAProfiling.c bugs were fixed by my previous commits).

Also make llvm-cov gcov on a little-endian host capable to parse big-endian .gcno and .gcda,
and make llvm-cov gcov on big-endian host capable to parse little-endian .gcno and .gcda
2020-06-03 19:29:21 -07:00
Fangrui Song 013f06703e [gcov] Emit GCOV_TAG_OBJECT_SUMMARY/GCOV_TAG_PROGRAM_SUMMARY correctly and fix llvm-cov's decoding of runcount
gcov 9 (r264462) started to use GCOV_TAG_OBJECT_SUMMARY. Before,
GCOV_TAG_PROGRAM_SUMMARY was used.
libclang_rt.profile should emit just one tag according to the version.

Another bug introduced by rL194499 is that the wrong runcount field was
selected.

Fix the two bugs so that gcov can correctly decode "Runs:" from
libclang_rt.profile produced .gcda files, and llvm-cov gcov can
correctly decode "Runs:" from libgcov produced .gcda files.
2020-05-11 21:53:53 -07:00
Fangrui Song f081150c4d [gcov] Implement --stdout -t
gcov by default prints to a .gcov file. With --stdout, stdout is used.
Some summary information is omitted. There is no separator for multiple
source files.
2020-05-10 21:02:38 -07:00
Fangrui Song 2d00eb17ca [gcov] Fix .gcda decoding and support GCC 8, 9 and 10
GCDAProfiling.c unnecessarily writes function names to .gcda files.
GCC 4.2 gcc/libgcov.c (now renamed to libgcc/libgcov*) did not write function
names. gcov-7 (compatible) crashes on .gcda produced by libclang_rt.profile
rL176173 realized the problem and introduced a mode to remove function
names.

llvm-cov code apparently takes GCDAProfiling.c output format as truth
and tries to decode function names.  Additionally, llvm-cov tries to
decode tags in certain order which does not match libgcov emitted .gcda
files.

This patch fixes the .gcda decoder and makes it work with GCC 8 and 9
(10 is compatible with 9). Note, line statistics are broken and not
fixed by this patch.

Add test/tools/llvm-cov/gcov-{4.7,8,9}.c to test compatibility.
2020-05-10 09:55:23 -07:00
Alexandre Ganea db817d15d1 [InstrProf] Silence warnings when targeting x86 with VS2019 16.5.4
Differential Revision: https://reviews.llvm.org/D79337
2020-05-06 09:12:00 -04:00
Sam McCall d10c995b4d std::isspace -> llvm::isSpace (where locale should be ignored)
I've left out some cases where I wasn't totally sure this was right or
whether the include was ok (compiler-rt) or idiomatic (flang).
2020-05-02 15:36:04 +02:00
Wei Mi b49eac71ad Recommit [SampleFDO] Add flag for partial profile.
Fix the error of show-prof-info.test on some platforms without zlib.

The common profile usage is to collect profile from a target and then use the profile to guide the optimized build for the same target. There are some cases that no profile can be collected for a target. In those cases, although no full profile is available, it is possible to have some partial profile collected from other targets to optimize common libraries and utilities. A flag is needed to tell the partial profile from the full profile apart, so compiler can use different strategy for them.

Differential Revision: https://reviews.llvm.org/D77426
2020-04-07 14:28:25 -07:00
Wei Mi c5da949ae8 Revert "[SampleFDO] Add flag for partial profile." show-prof-info.test breaks on some platforms.
This reverts commit e3ba652a14.
2020-04-07 12:54:51 -07:00
Wei Mi e3ba652a14 [SampleFDO] Add flag for partial profile.
The common profile usage is to collect profile from a target and then use the profile to guide the optimized build for the same target. There are some cases that no profile can be collected for a target. In those cases, although no full profile is available, it is possible to have some partial profile collected from other targets to optimize common libraries and utilities. A flag is needed to tell the partial profile from the full profile apart, so compiler can use different strategy for them.

Differential Revision: https://reviews.llvm.org/D77426
2020-04-07 12:17:56 -07:00
Wei Mi ebad678857 [SampleFDO] Port MD5 name table support to extbinary format.
Compbinary format uses MD5 to represent strings in name table. That gives smaller profile without the need of compression/decompression when writing/reading the profile. The patch adds the support in extbinary format. It is off by default but user can choose to enable it.

Note the feature of using MD5 in name table can bring very small chance of name conflict leading to profile mismatch. Besides, profile using the feature won't have the profile remapping support.

Differential Revision: https://reviews.llvm.org/D76255
2020-03-30 22:07:08 -07:00
Vedant Kumar 80cd518b80 [Coverage] Collect all function records in an object (D69471 followup)
After the format change from D69471, there can be more than one section
in an object that contains coverage function records. Look up each of
these sections and concatenate all the records together.

This re-enables the instrprof-merging.cpp test, which previously was
failing on OSes which use comdats.

Thanks to Jeremy Morse, who very kindly provided object files from the
bot I broke to help me debug.
2020-03-02 12:01:09 -08:00
Vedant Kumar dd1ea9de2e Reland: [Coverage] Revise format to reduce binary size
Try again with an up-to-date version of D69471 (99317124 was a stale
revision).

---

Revise the coverage mapping format to reduce binary size by:

1. Naming function records and marking them `linkonce_odr`, and
2. Compressing filenames.

This shrinks the size of llc's coverage segment by 82% (334MB -> 62MB)
and speeds up end-to-end single-threaded report generation by 10%. For
reference the compressed name data in llc is 81MB (__llvm_prf_names).

Rationale for changes to the format:

- With the current format, most coverage function records are discarded.
  E.g., more than 97% of the records in llc are *duplicate* placeholders
  for functions visible-but-not-used in TUs. Placeholders *are* used to
  show under-covered functions, but duplicate placeholders waste space.

- We reached general consensus about giving (1) a try at the 2017 code
  coverage BoF [1]. The thinking was that using `linkonce_odr` to merge
  duplicates is simpler than alternatives like teaching build systems
  about a coverage-aware database/module/etc on the side.

- Revising the format is expensive due to the backwards compatibility
  requirement, so we might as well compress filenames while we're at it.
  This shrinks the encoded filenames in llc by 86% (12MB -> 1.6MB).

See CoverageMappingFormat.rst for the details on what exactly has
changed.

Fixes PR34533 [2], hopefully.

[1] http://lists.llvm.org/pipermail/llvm-dev/2017-October/118428.html
[2] https://bugs.llvm.org/show_bug.cgi?id=34533

Differential Revision: https://reviews.llvm.org/D69471
2020-02-28 18:12:04 -08:00
Vedant Kumar 3388871714 Revert "[Coverage] Revise format to reduce binary size"
This reverts commit 99317124e1. This is
still busted on Windows:

http://lab.llvm.org:8011/builders/lld-x86_64-win7/builds/40873

The llvm-cov tests report 'error: Could not load coverage information'.
2020-02-28 18:03:15 -08:00
Vedant Kumar 99317124e1 [Coverage] Revise format to reduce binary size
Revise the coverage mapping format to reduce binary size by:

1. Naming function records and marking them `linkonce_odr`, and
2. Compressing filenames.

This shrinks the size of llc's coverage segment by 82% (334MB -> 62MB)
and speeds up end-to-end single-threaded report generation by 10%. For
reference the compressed name data in llc is 81MB (__llvm_prf_names).

Rationale for changes to the format:

- With the current format, most coverage function records are discarded.
  E.g., more than 97% of the records in llc are *duplicate* placeholders
  for functions visible-but-not-used in TUs. Placeholders *are* used to
  show under-covered functions, but duplicate placeholders waste space.

- We reached general consensus about giving (1) a try at the 2017 code
  coverage BoF [1]. The thinking was that using `linkonce_odr` to merge
  duplicates is simpler than alternatives like teaching build systems
  about a coverage-aware database/module/etc on the side.

- Revising the format is expensive due to the backwards compatibility
  requirement, so we might as well compress filenames while we're at it.
  This shrinks the encoded filenames in llc by 86% (12MB -> 1.6MB).

See CoverageMappingFormat.rst for the details on what exactly has
changed.

Fixes PR34533 [2], hopefully.

[1] http://lists.llvm.org/pipermail/llvm-dev/2017-October/118428.html
[2] https://bugs.llvm.org/show_bug.cgi?id=34533

Differential Revision: https://reviews.llvm.org/D69471
2020-02-28 17:33:25 -08:00
Bill Wendling c55cf4afa9 Revert "Remove redundant "std::move"s in return statements"
The build failed with

  error: call to deleted constructor of 'llvm::Error'

errors.

This reverts commit 1c2241a793.
2020-02-10 07:07:40 -08:00
Bill Wendling 1c2241a793 Remove redundant "std::move"s in return statements 2020-02-10 06:39:44 -08:00
Jonas Devlieghere b2924d9956 [llvm] Replace SmallStr.str().str() with std::string conversion operator.
Use the std::string conversion operator introduced in
d7049213d0.
2020-01-29 21:16:46 -08:00
Benjamin Kramer a9bc7b83a4 Another round of GCC5 fixes. 2020-01-29 02:09:24 +01:00
Benjamin Kramer adcd026838 Make llvm::StringRef to std::string conversions explicit.
This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.

This doesn't actually modify StringRef yet, I'll do that in a follow-up.
2020-01-28 23:25:25 +01:00
James Henderson d68904f957 [NFC] Fix trivial typos in comments
Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D72143

Patch by Kazuaki Ishizaki.
2020-01-06 10:50:26 +00:00
Vedant Kumar f208b70fbc Revert "[Coverage] Revise format to reduce binary size"
This reverts commit e18531595b.

On Windows, there is an error:

http://lab.llvm.org:8011/builders/sanitizer-windows/builds/54963/steps/stage%201%20check/logs/stdio

error: C:\b\slave\sanitizer-windows\build\stage1\projects\compiler-rt\test\profile\Profile-x86_64\Output\instrprof-merging.cpp.tmp.v1.o: Failed to load coverage: Malformed coverage data
2019-12-04 10:35:14 -08:00
Vedant Kumar e18531595b [Coverage] Revise format to reduce binary size
Revise the coverage mapping format to reduce binary size by:

1. Naming function records and marking them `linkonce_odr`, and
2. Compressing filenames.

This shrinks the size of llc's coverage segment by 82% (334MB -> 62MB)
and speeds up end-to-end single-threaded report generation by 10%. For
reference the compressed name data in llc is 81MB (__llvm_prf_names).

Rationale for changes to the format:

- With the current format, most coverage function records are discarded.
  E.g., more than 97% of the records in llc are *duplicate* placeholders
  for functions visible-but-not-used in TUs. Placeholders *are* used to
  show under-covered functions, but duplicate placeholders waste space.

- We reached general consensus about giving (1) a try at the 2017 code
  coverage BoF [1]. The thinking was that using `linkonce_odr` to merge
  duplicates is simpler than alternatives like teaching build systems
  about a coverage-aware database/module/etc on the side.

- Revising the format is expensive due to the backwards compatibility
  requirement, so we might as well compress filenames while we're at it.
  This shrinks the encoded filenames in llc by 86% (12MB -> 1.6MB).

See CoverageMappingFormat.rst for the details on what exactly has
changed.

Fixes PR34533 [2], hopefully.

[1] http://lists.llvm.org/pipermail/llvm-dev/2017-October/118428.html
[2] https://bugs.llvm.org/show_bug.cgi?id=34533

Differential Revision: https://reviews.llvm.org/D69471
2019-12-04 10:10:55 -08:00
Tom Stellard ab411801b8 [cmake] Explicitly mark libraries defined in lib/ as "Component Libraries"
Summary:
Most libraries are defined in the lib/ directory but there are also a
few libraries defined in tools/ e.g. libLLVM, libLTO.  I'm defining
"Component Libraries" as libraries defined in lib/ that may be included in
libLLVM.so.  Explicitly marking the libraries in lib/ as component
libraries allows us to remove some fragile checks that attempt to
differentiate between lib/ libraries and tools/ libraires:

1. In tools/llvm-shlib, because
llvm_map_components_to_libnames(LIB_NAMES "all") returned a list of
all libraries defined in the whole project, there was custom code
needed to filter out libraries defined in tools/, none of which should
be included in libLLVM.so.  This code assumed that any library
defined as static was from lib/ and everything else should be
excluded.

With this change, llvm_map_components_to_libnames(LIB_NAMES, "all")
only returns libraries that have been added to the LLVM_COMPONENT_LIBS
global cmake property, so this custom filtering logic can be removed.
Doing this also fixes the build with BUILD_SHARED_LIBS=ON
and LLVM_BUILD_LLVM_DYLIB=ON.

2. There was some code in llvm_add_library that assumed that
libraries defined in lib/ would not have LLVM_LINK_COMPONENTS or
ARG_LINK_COMPONENTS set.  This is only true because libraries
defined lib lib/ use LLVMBuild.txt and don't set these values.
This code has been fixed now to check if the library has been
explicitly marked as a component library, which should now make it
easier to remove LLVMBuild at some point in the future.

I have tested this patch on Windows, MacOS and Linux with release builds
and the following combinations of CMake options:

- "" (No options)
- -DLLVM_BUILD_LLVM_DYLIB=ON
- -DLLVM_LINK_LLVM_DYLIB=ON
- -DBUILD_SHARED_LIBS=ON
- -DBUILD_SHARED_LIBS=ON -DLLVM_BUILD_LLVM_DYLIB=ON
- -DBUILD_SHARED_LIBS=ON -DLLVM_LINK_LLVM_DYLIB=ON

Reviewers: beanz, smeenai, compnerd, phosek

Reviewed By: beanz

Subscribers: wuzish, jholewinski, arsenm, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, mgorny, mehdi_amini, sbc100, jgravelle-google, hiraditya, aheejin, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, steven_wu, rogfer01, MartinMosbeck, brucehoult, the_o, dexonsmith, PkmX, jocewei, jsji, dang, Jim, lenary, s.egerton, pzheng, sameer.abuasal, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70179
2019-11-21 10:48:08 -08:00
Vedant Kumar d889d1efef [profile] Add a mode to continuously sync counter updates to a file
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
2019-10-31 16:04:09 -07:00
Wei Mi 8c8ec1f686 [SampleFDO] Add profile remapping support for profile on-demand loading used
by ExtBinary format profile

Profile on-demand loading was added for ExtBinary format profile in rL374233,
but currently profile on-demand loading doesn't work well with profile
remapping. The patch adds the support.

Suppose a function in the current module has outline instance in the profile.
The function name in the module is different from the name of the outline
instance, but remapper knows the two names are equal. When loading profile
on-demand, the outline instance has to be loaded with remapper's help.

At the same time SampleProfileReaderItaniumRemapper is changed from a proxy
of SampleProfileReader to a helper member in SampleProfileReader.

Differential Revision: https://reviews.llvm.org/D68901

llvm-svn: 375295
2019-10-18 22:35:20 +00:00
Guillaume Chatelet ce56e1a1cc [Alignment][NFC] Move and type functions from MathExtras to Alignment
Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68942

llvm-svn: 374773
2019-10-14 13:14:34 +00:00
Wei Mi 09dcfe6805 [SampleFDO] Add indexing for function profiles so they can be loaded on demand
in ExtBinary format

Currently for Text, Binary and ExtBinary format profiles, when we compile a
module with samplefdo, even if there is no function showing up in the profile,
we have to load all the function profiles from the profile input. That is a
waste of compile time.

CompactBinary format profile has already had the support of loading function
profiles on demand. In this patch, we add the support to load profile on
demand for ExtBinary format. It will work no matter the sections in ExtBinary
format profile are compressed or not. Experiment shows it reduces the time to
compile a server benchmark by 30%.

When profile remapping and loading function profiles on demand are both used,
extra work needs to be done so that the loading on demand process will take
the name remapping into consideration. It will be addressed in a follow-up
patch.

Differential Revision: https://reviews.llvm.org/D68601

llvm-svn: 374233
2019-10-09 21:36:03 +00:00
Wei Mi 283df8cf74 Fix build errors caused by rL373914.
llvm-svn: 373919
2019-10-07 16:45:47 +00:00
Wenlei He b3342e180e [llvm-profdata] Minor format fix
Summary: Minor format fix for output of "llvm-profdata -show"

Reviewers: wmi

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68440

llvm-svn: 373917
2019-10-07 16:30:31 +00:00
Wei Mi b523790ae1 [SampleFDO] Add compression support for any section in ExtBinary profile format
Previously ExtBinary profile format only supports compression using zlib for
profile symbol list. In this patch, we extend the compression support to any
section. User can select some or all of the sections to compress. In an
experiment, for a 45M profile in ExtBinary format, compressing name table
reduced its size to 24M, and compressing all the sections reduced its size
to 11M.

Differential Revision: https://reviews.llvm.org/D68253

llvm-svn: 373914
2019-10-07 16:12:37 +00:00
Rong Xu e0fa2689de [PGO] Fix typos from r359612. NFC.
llvm-svn: 373369
2019-10-01 18:06:50 +00:00
Simon Pilgrim 339b1b5bb0 InstrProf - avoid static analyzer dyn_cast<ConstantInt> null dereference warning.
The static analyzer is warning about a potential null dereference, as we're already earlying-out for a null Constant pointer I've just folded this into a dyn_cast_or_null<ConstantInt>.

No test case, this is by inspection only.

llvm-svn: 373322
2019-10-01 10:38:30 +00:00
Wei Mi eee532cd5f Recommit [SampleFDO] Expose an interface to return the size of a section
or the size of the profile for profile in ExtBinary format.

Fix a test failure on Mac.

[SampleFDO] Expose an interface to return the size of a section or the
size of the profile for profile in ExtBinary format.

Sometimes we want to limit the size of the profile by stripping some functions
with low sample count or by stripping some function names with small text size
from profile symbol list. That requires the profile reader to have the
interfaces returning the size of a section or the size of total profile. The
patch add those interfaces.

At the same time, add some dump facility to show the size of each section.

Differential revision: https://reviews.llvm.org/D67726

llvm-svn: 372478
2019-09-21 17:23:55 +00:00
Amara Emerson 3bb56fa478 Revert "[SampleFDO] Expose an interface to return the size of a section or the size"
This reverts commit f118852046.

Broke the macOS build/greendragon bots.

llvm-svn: 372464
2019-09-21 09:11:51 +00:00
Wei Mi f118852046 [SampleFDO] Expose an interface to return the size of a section or the size
of the profile for profile in ExtBinary format.

Sometimes we want to limit the size of the profile by stripping some functions
with low sample count or by stripping some function names with small text size
from profile symbol list. That requires the profile reader to have the
interfaces returning the size of a section or the size of total profile. The
patch add those interfaces.

At the same time, add some dump facility to show the size of each section.

llvm-svn: 372439
2019-09-20 23:24:50 +00:00
Alexander Shaposhnikov 4fd11c1e45 [Object] Extend MachOUniversalBinary::getObjectForArch
Make the method MachOUniversalBinary::getObjectForArch return MachOUniversalBinary::ObjectForArch
and add helper methods MachOUniversalBinary::getMachOObjectForArch, MachOUniversalBinary::getArchiveForArch
for those who explicitly expect to get a MachOObjectFile or an Archive.

Differential revision: https://reviews.llvm.org/D67700

Test plan: make check-all

llvm-svn: 372278
2019-09-19 00:02:12 +00:00
Teresa Johnson fd2044f299 [PGO] Change hardcoded thresholds for cold/inlinehint to use summary
Summary:
The PGO counter reading will add cold and inlinehint (hot) attributes
to functions that are very cold or hot. This was using hardcoded
thresholds, instead of the profile summary cutoffs which are used in
other hot/cold detection and are more dynamic and adaptable. Switch
to using the summary-based cold/hot detection.

The hardcoded limits were causing some code that had a medium level of
hotness (per the summary) to be incorrectly marked with a cold
attribute, blocking inlining.

Reviewers: davidxl

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67673

llvm-svn: 372189
2019-09-17 23:12:13 +00:00
Vedant Kumar 413647d730 [Coverage] Speed up file-based queries for coverage info, NFC
Speed up queries for coverage info in a file by reducing the amount of
time spent determining whether a function record corresponds to a file.

This gives a 36% speedup when generating a coverage report for `llc`.
The reduction is entirely in user time.

rdar://54758110

Differential Revision: https://reviews.llvm.org/D67575

llvm-svn: 372025
2019-09-16 19:08:44 +00:00
Vedant Kumar 95de24978e [Coverage] Assert that filenames in a TU are unique, NFC
llvm-svn: 372024
2019-09-16 19:08:41 +00:00
Vedant Kumar 95fb23ab37 [InstrProf] Tighten a check for malformed data records in raw profiles
The check needs to validate a counter offset before performing pointer
arithmetic with the (potentially corrupt) offset.

Found by UBSan's pointer overflow check.

rdar://54843625

Differential Revision: https://reviews.llvm.org/D66979

llvm-svn: 370826
2019-09-03 22:23:14 +00:00
Wei Mi 198009ae8d Fix some errors introduced by rL370563 which were not exposed on my local machine.
1. zlib::compress accept &size_t but the param is an uint64_t.
2. Some systems don't have zlib installed. Don't use compression by default.

llvm-svn: 370564
2019-08-31 03:17:49 +00:00
Wei Mi 798e59b81f [SampleFDO] Add profile symbol list section to discriminate function being
cold versus function being newly added.

This is the second half of https://reviews.llvm.org/D66374.

Profile symbol list is the collection of function symbols showing up in
the binary which generates the current profile. It is used to discriminate
function being cold versus function being newly added. Profile symbol list
is only added for profile with ExtBinary format.

During profile use compilation, when profile-sample-accurate is enabled,
a function without profile will be regarded as cold only when it is
contained in that list.

Differential Revision: https://reviews.llvm.org/D66766

llvm-svn: 370563
2019-08-31 02:27:26 +00:00
James Y Knight f025968bcc Ignore object files that lack coverage information.
Before this change, if multiple binary files were presented, all of them must have been instrumented or the load would fail with coverage_map_error::no_data_found.

Patch by Dean Sturtevant.

Differential Revision: https://reviews.llvm.org/D66763

llvm-svn: 370257
2019-08-28 20:35:50 +00:00
Wei Mi 077a9c7053 [SampleFDO] Extract the code calling each section reader to readOneSection.
This is a followup of https://reviews.llvm.org/D66513. The code calling each
section reader should be put into a separate function (readOneSection), so
SampleProfileExtBinaryReader can override it. Otherwise, the base class
SampleProfileExtBinaryBaseReader will need to be aware of all different kinds
of section readers. That is not right.

Differential Revision: https://reviews.llvm.org/D66693

llvm-svn: 369919
2019-08-26 15:54:16 +00:00
Wei Mi be9073249e [SampleFDO] Add ExtBinary format to support extension of binary profile.
This is a patch split from https://reviews.llvm.org/D66374. It tries to add
a new format of profile called ExtBinary. The format adds a section header
table to the profile and organize the profile in sections, so the future
extension like adding a new section or extending an existing section will be
easier while keeping backward compatiblity feasible.

Differential Revision: https://reviews.llvm.org/D66513

llvm-svn: 369798
2019-08-23 19:05:30 +00:00
Wenlei He 5adace352d [AutoFDO] Make call targets order deterministic for sample profile
Summary:
StringMap is used for storing call target to frequency map for AutoFDO. However the iterating order of StringMap is non-deterministic, which leads to non-determinism in AutoFDO profile output. Now new API getSortedCallTargets and SortCallTargets are added for deterministic ordering and output.

Roundtrip test for text profile and binary profile is added.

Reviewers: wmi, davidxl, danielcdh

Subscribers: hiraditya, mgrang, llvm-commits, twoh

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66191

llvm-svn: 369440
2019-08-20 20:52:00 +00:00
Jonas Devlieghere 0eaee545ee [llvm] Migrate llvm::make_unique to std::make_unique
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.

llvm-svn: 369013
2019-08-15 15:54:37 +00:00
George Rimar bcc00e1afb Recommit r368812 "[llvm/Object] - Convert SectionRef::getName() to return Expected<>"
Changes: no changes. A fix for the clang code will be landed right on top.

Original commit message:

SectionRef::getName() returns std::error_code now.
Returning Expected<> instead has multiple benefits.

For example, it forces user to check the error returned.
Also Expected<> may keep a valuable string error message,
what is more useful than having a error code.
(Object\invalid.test was updated to show the new messages printed.)

This patch makes a change for all users to switch to Expected<> version.

Note: in a few places the error returned was ignored before my changes.
In such places I left them ignored. My intention was to convert the interface
used, and not to improve and/or the existent users in this patch.
(Though I think this is good idea for a follow-ups to revisit such places
and either remove consumeError calls or comment each of them to clarify why
it is OK to have them).

Differential revision: https://reviews.llvm.org/D66089

llvm-svn: 368826
2019-08-14 11:10:11 +00:00
George Rimar 468919e182 Revert r368812 "[llvm/Object] - Convert SectionRef::getName() to return Expected<>"
It broke clang BB: http://lab.llvm.org:8011/builders/clang-x86_64-debian-fast/builds/16455

llvm-svn: 368813
2019-08-14 08:56:55 +00:00
George Rimar a0c6a35714 [llvm/Object] - Convert SectionRef::getName() to return Expected<>
SectionRef::getName() returns std::error_code now.
Returning Expected<> instead has multiple benefits.

For example, it forces user to check the error returned.
Also Expected<> may keep a valuable string error message,
what is more useful than having a error code.
(Object\invalid.test was updated to show the new messages printed.)

This patch makes a change for all users to switch to Expected<> version.

Note: in a few places the error returned was ignored before my changes.
In such places I left them ignored. My intention was to convert the interface
used, and not to improve and/or the existent users in this patch.
(Though I think this is good idea for a follow-ups to revisit such places
and either remove consumeError calls or comment each of them to clarify why
it is OK to have them).

Differential revision: https://reviews.llvm.org/D66089

llvm-svn: 368812
2019-08-14 08:46:54 +00:00
Wenlei He d328954467 [llvm-profdata] Profile dump for compact binary format
Summary: Fix "llvm-profdata show" so it can work with compact binary format profile. The change is to mark all functions "used" so SampleProfileReaderCompactBinary::read will read in all profiles available for dumping. The function names will be MD5 hash for compact binary format.

Reviewers: wmi, davidxl, danielcdh

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65162

llvm-svn: 368731
2019-08-13 17:56:08 +00:00
Wenlei He 4b99b58a84 [ThinLTO][AutoFDO] Fix memory corruption due to race condition from thin backends
Summary:
This commit fixed a race condition from multi-threaded thinLTO backends that causes non-deterministic memory corruption for a data structure used only by AutoFDO with compact binary profile.
GUIDToFuncNameMap, a static data member of type DenseMap in FunctionSamples is used as a per-module mapping from function name MD5 to name string when input AutoFDO profile is in compact binary format. However with ThinLTO, we can have parallel backends modifying and accessing the class static map concurrently. The fix is to make GUIDToFuncNameMap a member of SampleProfileLoader instead of a file static data.

Reviewers: wmi, davidxl, danielcdh

Subscribers: mehdi_amini, inglorion, hiraditya, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65848

llvm-svn: 368596
2019-08-12 17:45:14 +00:00
Wenlei He d664072dd5 Revert "test commit"
This reverts commit ad92a4a2769425ad0d39ac1dbb6282f6f51a1af7.

llvm-svn: 368525
2019-08-11 05:59:20 +00:00
Wenlei He 7bd327da00 test commit
llvm-svn: 368524
2019-08-11 05:50:28 +00:00
Fangrui Song d9b948b6eb Rename F_{None,Text,Append} to OF_{None,Text,Append}. NFC
F_{None,Text,Append} are kept for compatibility since r334221.

llvm-svn: 367800
2019-08-05 05:43:48 +00:00
Vedant Kumar d6c15b661a [Profile] Support raw/indexed profiles larger than 4GB
rdar://45955976

llvm-svn: 365565
2019-07-09 22:01:04 +00:00
Fangrui Song 78ee2fbf98 Cleanup: llvm::bsearch -> llvm::partition_point after r364719
llvm-svn: 364720
2019-06-30 11:19:56 +00:00
Fangrui Song dc8de6037c Simplify std::lower_bound with llvm::{bsearch,lower_bound}. NFC
llvm-svn: 364006
2019-06-21 05:40:31 +00:00
Vedant Kumar 1e4882c890 [Coverage] Speculative fix for r363325 for an older compiler
It looks like an older version of gcc can't figure out that it needs to
move a unique_ptr while implicitly constructing an Expected object.

llvm-svn: 363342
2019-06-14 00:03:22 +00:00
Vedant Kumar 901d04fc6d [Coverage] Load code coverage data from archives
Support loading code coverage data from regular archives, thin archives,
and from MachO universal binaries which contain archives.

Testing: check-llvm, check-profile (with {A,UB}San enabled)

rdar://51538999

Differential Revision: https://reviews.llvm.org/D63232

llvm-svn: 363325
2019-06-13 20:48:57 +00:00
Fangrui Song e183340c29 Recommit [Object] Change object::SectionRef::getContents() to return Expected<StringRef>
r360876 didn't fix 2 call sites in clang.

Expected<ArrayRef<uint8_t>> may be better but use Expected<StringRef> for now.

Follow-up of D61781.

llvm-svn: 360892
2019-05-16 13:24:04 +00:00
Hans Wennborg 4da9ff9fcf Revert r360876 "[Object] Change object::SectionRef::getContents() to return Expected<StringRef>"
It broke the Clang build, see llvm-commits thread.

> Expected<ArrayRef<uint8_t>> may be better but use Expected<StringRef> for now.
>
> Follow-up of D61781.

llvm-svn: 360878
2019-05-16 12:08:34 +00:00
Fangrui Song a076ec54be [Object] Change object::SectionRef::getContents() to return Expected<StringRef>
Expected<ArrayRef<uint8_t>> may be better but use Expected<StringRef> for now.

Follow-up of D61781.

llvm-svn: 360876
2019-05-16 11:33:48 +00:00
Eric Christopher 6435102c03 Fix a few -Werror warnings:
- Remove a variable only used in an assert
 - Fix pessimizing move warning around copy elision

llvm-svn: 359617
2019-04-30 21:44:21 +00:00
Rong Xu 998b97f6f1 [llvm-profdata] Add overlap command to compute similarity b/w two profile files
Add overlap functionality to llvm-profdata tool to compute the similarity
between two profile files.

Differential Revision: https://reviews.llvm.org/D60977

llvm-svn: 359612
2019-04-30 21:19:12 +00:00
Dmitry Mikulin 312b5f86b7 The error message for mismatched value sites is very cryptic.
Make it more readable for an average user.

Differential Revision: https://reviews.llvm.org/D60896

llvm-svn: 359043
2019-04-23 22:26:55 +00:00
Fangrui Song efd94c56ba Use llvm::stable_sort
While touching the code, simplify if feasible.

llvm-svn: 358996
2019-04-23 14:51:27 +00:00
Fangrui Song 6a0746a92f Change some StringRef::data() reinterpret_cast to bytes_begin() or arrayRefFromStringRef()
llvm-svn: 357852
2019-04-07 03:58:42 +00:00
Taewook Oh a960f89962 [ProfileSummary] Count callsite samples when computing total samples.
Summary: Currently ProfileSummaryBuilder doesn't count into callsite samples when computing total samples. Considering that ProfileSummaryInfo is used to checked the hotness of not only body samples but also callsite samples (from SampleProfileLoader), I think the callsite sample counts should be considered when computing total samples.

Reviewers: eraman, danielcdh, wmi

Subscribers: hiraditya, jdoerfert, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59835

llvm-svn: 357627
2019-04-03 19:54:43 +00:00
Than McIntosh 9f96f1f17a [SampleFDO] add suffix elision control for fcn names
Summary:
Add hooks for determining the policy used to decide whether/how
to chop off symbol 'suffixes' when locating a given function
in a sample profile.

Prior to this change, any function symbols of the form "X.Y" were
elided/truncated into just "X" when looking up things in a sample
profile data file.

With this change, the policy on suffixes can be changed by adding a
new attribute "sample-profile-suffix-elision-policy" to the function:
this attribute can have the value "all" (the default), "selected", or
"none". A value of "all" preserves the previous behavior (chop off
everything after the first "." character, then treat that as the
symbol name). A value of "selected" chops off only the rightmost
".llvm.XXXX" suffix (where "XXX" is any string not containing a "."
char). A value of "none" indicates that names should be left as is.

Subscribers: jdoerfert, wmi, mtrofin, danielcdh, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58832

llvm-svn: 356146
2019-03-14 13:56:49 +00:00
Rong Xu 05c0afe842 [PGO] Context sensitive PGO (part 4)
Part 4 of CSPGO changes:
(1) add support in cmake for cspgo build.
(2) fix an issue in big endian.
(3) test cases.

Differential Revision: https://reviews.llvm.org/D54175

llvm-svn: 355541
2019-03-06 19:31:37 +00:00
Mandeep Singh Grang a14f20c5b3 [ProfileData] Sort FuncData before iteration to remove non-determinism
Reviewers: rsmith, bogner, dblaikie

Reviewed By: dblaikie

Subscribers: Hahnfeld, jdoerfert, vsk, dblaikie, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D57986

llvm-svn: 355252
2019-03-02 00:47:43 +00:00
Rong Xu a6ff69f6dd [PGO] Context sensitive PGO (part 2)
Part 2 of CSPGO changes (mostly related to ProfileSummary).
Note that I use a default parameter in setProfileSummary() and getSummary().
This is to break the dependency in clang. I will make the parameter explicit
after changing clang in a separated patch.

Differential Revision: https://reviews.llvm.org/D54175

llvm-svn: 355131
2019-02-28 19:55:07 +00:00
Rong Xu 6cdf3d8086 Recommit r354930 "[PGO] Context sensitive PGO (part 1)"
Fixed UBSan failures.

llvm-svn: 355005
2019-02-27 17:24:33 +00:00
Vlad Tsyrklevich c01643087e Revert "[PGO] Context sensitive PGO (part 1)"
This reverts commit r354930, it was causing UBSan failures.

llvm-svn: 354953
2019-02-27 03:45:28 +00:00
Rong Xu 35d2d51369 [PGO] Context sensitive PGO (part 1)
Current PGO profile counts are not context sensitive. The branch probabilities
for the inlined functions are kept the same for all call-sites, and they might
be very different from the actual branch probabilities. These suboptimal
profiles can greatly affect some downstream optimizations, in particular for
the machine basic block placement optimization.

In this patch, we propose to have a post-inline PGO instrumentation/use pass,
which we called Context Sensitive PGO (CSPGO). For the users who want the best
possible performance, they can perform a second round of PGO instrument/use on
the top of the regular PGO. They will have two sets of profile counts. The
first pass profile will be manly for inline, indirect-call promotion, and
CGSCC simplification pass optimizations. The second pass profile is for
post-inline optimizations and code-gen optimizations.

A typical usage:
// Regular PGO instrumentation and generate pass1 profile.
> clang -O2 -fprofile-generate source.c -o gen
> ./gen
> llvm-profdata merge default.*profraw -o pass1.profdata
// CSPGO instrumentation.
> clang -O2 -fprofile-use=pass1.profdata -fcs-profile-generate -o gen2
> ./gen2
// Merge two sets of profiles
> llvm-profdata merge default.*profraw pass1.profdata -o profile.profdata
// Use the combined profile. Pass manager will invoke two PGO use passes.
> clang -O2 -fprofile-use=profile.profdata -o use

This change touches many components in the compiler. The reviewed patch
(D54175) will committed in phrases.

Differential Revision: https://reviews.llvm.org/D54175

llvm-svn: 354930
2019-02-26 22:37:46 +00:00
Reid Kleckner 8b6af00173 [llvm-cov] Fix llvm-cov on Windows and un-XFAIL test
Summary:
The llvm-cov tool needs to be able to find coverage names in the
executable, so the .lprfn and .lcovmap sections cannot be merged into
.rdata.

Also, the linker merges .lprfn$M into .lprfn, so llvm-cov needs to
handle that when looking up sections. It has to support running on both
relocatable object files and linked PE files.

Lastly, when loading .lprfn from a PE file, llvm-cov needs to skip the
leading zero byte added by the profile runtime.

Reviewers: vsk

Subscribers: hiraditya, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D58661

llvm-svn: 354840
2019-02-26 02:30:00 +00:00