[BOLT] Compress YAML pseudo probe information

[aaupov]

Introduce an optional value compact for profile-write-pseudo-probes flag,
enabling compressed encoding of pseudo probe information in YAML profile:

• block probes are encoded into space-separated list of probes grouped by
  inline tree nodes in format [probes]_[nodes]:
  • probes and nodes are comma-separated indices,
  • contiguous spans [from,...,to] are coalesced into from^run_length,
  • probes, nodes, and run lengths are base36-encoded,
  • omissions: head probe (index = 1), root node (node = 0).
• inline tree is encoded into space-separated list of node descriptions
  using base36-encoding.
• the character set is selected to avoid quoting.

This significantly reduces the size of YAML profile and makes parsing faster
(as it replaces nested FlowVectors with strings).

Test Plan:

• CSSPGO Clang-BOLT ([Clang][CMake] Add CSSPGO support to LLVM_BUILD_INSTRUMENTED #79942)
• profile size: 241MB->140MB,
• pre-process profile data:
  • wall time 9.8217s -> 1.8332s,
  • peak RSS 11 GiB -> 2.4GiB

TBD: compress pseudo_probe_desc. Use DFS for probes, and BFS for inline tree.
Measure emission time.

[github-actions]

⚠️ C/C++ code formatter, clang-format found issues in your code. ⚠️

You can test this locally with the following command:

git-clang-format --diff origin/main HEAD --extensions cpp,h -- bolt/include/bolt/Profile/ProfileYAMLMapping.h bolt/include/bolt/Profile/YAMLProfileWriter.h bolt/include/bolt/Utils/CommandLineOpts.h bolt/lib/Profile/DataAggregator.cpp bolt/lib/Profile/YAMLProfileReader.cpp bolt/lib/Profile/YAMLProfileWriter.cpp bolt/lib/Rewrite/PseudoProbeRewriter.cpp --diff_from_common_commit

⚠️
The reproduction instructions above might return results for more than one PR
in a stack if you are using a stacked PR workflow. You can limit the results by
changing origin/main to the base branch/commit you want to compare against.
⚠️

View the diff from clang-format here.

diff --git a/bolt/lib/Profile/YAMLProfileWriter.cpp b/bolt/lib/Profile/YAMLProfileWriter.cpp
index aad433a8b..817590cb9 100644
--- a/bolt/lib/Profile/YAMLProfileWriter.cpp
+++ b/bolt/lib/Profile/YAMLProfileWriter.cpp
@@ -485,7 +485,7 @@ std::error_code YAMLProfileWriter::writeProfile(const RewriteInstance &RI) {
   // Add probe inline tree nodes.
   InlineTreeDesc InlineTree;
   if (const MCPseudoProbeDecoder *Decoder =
-      opts::ProfileWritePseudoProbes ? BC.getPseudoProbeDecoder() : nullptr)
+          opts::ProfileWritePseudoProbes ? BC.getPseudoProbeDecoder() : nullptr)
     std::tie(BP.PseudoProbeDesc, InlineTree) = convertPseudoProbeDesc(*Decoder);
 
   // Add all function objects.

[github-actions]

🐧 Linux x64 Test Results

The build failed before running any tests. Click on a failure below to see the details.

tools/bolt/lib/Profile/CMakeFiles/LLVMBOLTProfile.dir/YAMLProfileReader.cpp.o

FAILED: tools/bolt/lib/Profile/CMakeFiles/LLVMBOLTProfile.dir/YAMLProfileReader.cpp.o
sccache /opt/llvm/bin/clang++ -DCMAKE_INSTALL_FULL_LIBDIR=\"/home/gha/actions-runner/_work/llvm-project/llvm-project/build/install/lib\" -DGTEST_HAS_RTTI=0 -DLLVM_BUILD_STATIC -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GLIBCXX_USE_CXX11_ABI=1 -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/gha/actions-runner/_work/llvm-project/llvm-project/build/tools/bolt/lib/Profile -I/home/gha/actions-runner/_work/llvm-project/llvm-project/bolt/lib/Profile -I/home/gha/actions-runner/_work/llvm-project/llvm-project/build/include -I/home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/include -I/home/gha/actions-runner/_work/llvm-project/llvm-project/bolt/include -I/home/gha/actions-runner/_work/llvm-project/llvm-project/build/tools/bolt/include -gmlt -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wno-pass-failed -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -std=c++17  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -MD -MT tools/bolt/lib/Profile/CMakeFiles/LLVMBOLTProfile.dir/YAMLProfileReader.cpp.o -MF tools/bolt/lib/Profile/CMakeFiles/LLVMBOLTProfile.dir/YAMLProfileReader.cpp.o.d -o tools/bolt/lib/Profile/CMakeFiles/LLVMBOLTProfile.dir/YAMLProfileReader.cpp.o -c /home/gha/actions-runner/_work/llvm-project/llvm-project/bolt/lib/Profile/YAMLProfileReader.cpp
/home/gha/actions-runner/_work/llvm-project/llvm-project/bolt/lib/Profile/YAMLProfileReader.cpp:385:39: error: no member named 'ParentIndex' in 'llvm::yaml::bolt::InlineTreeNode'
385 |       Fields[1].getAsInteger(36, Node.ParentIndex);
|                                  ~~~~ ^
/home/gha/actions-runner/_work/llvm-project/llvm-project/bolt/lib/Profile/YAMLProfileReader.cpp:397:24: error: use of undeclared identifier 'YamlPD'
397 |     uint32_t HashIdx = YamlPD.GUIDHashIdx[GUIDIdx];
|                        ^~~~~~
/home/gha/actions-runner/_work/llvm-project/llvm-project/bolt/lib/Profile/YAMLProfileReader.cpp:399:27: error: use of undeclared identifier 'YamlPD'
399 |     InlineTreeNode.GUID = YamlPD.GUID[GUIDIdx];
|                           ^~~~~~
/home/gha/actions-runner/_work/llvm-project/llvm-project/bolt/lib/Profile/YAMLProfileReader.cpp:400:27: error: use of undeclared identifier 'YamlPD'
400 |     InlineTreeNode.Hash = YamlPD.Hash[HashIdx];
|                           ^~~~~~
/home/gha/actions-runner/_work/llvm-project/llvm-project/bolt/lib/Profile/YAMLProfileReader.cpp:994:18: error: explicit template parameter list for lambdas is a C++20 extension [-Werror,-Wc++20-extensions]
994 |   auto CmpAt = []<auto N>(const auto &LHS, const auto &RHS) {
|                  ^
/home/gha/actions-runner/_work/llvm-project/llvm-project/bolt/lib/Profile/YAMLProfileReader.cpp:1016:14: error: placeholder variables are a C++2c extension [-Werror,-Wc++26-extensions]
1016 |     auto [_, _, _, YamlBF] = *PRange.first;
|              ^
/home/gha/actions-runner/_work/llvm-project/llvm-project/bolt/lib/Profile/YAMLProfileReader.cpp:1016:17: error: placeholder variables are a C++2c extension [-Werror,-Wc++26-extensions]
1016 |     auto [_, _, _, YamlBF] = *PRange.first;
|                 ^
/home/gha/actions-runner/_work/llvm-project/llvm-project/bolt/lib/Profile/YAMLProfileReader.cpp:1016:10: error: unused variable '[_, _, _, YamlBF]' [-Werror,-Wunused-variable]
1016 |     auto [_, _, _, YamlBF] = *PRange.first;
|          ^
8 errors generated.

If these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the infrastructure label.