Rebase: [Facebook] Add clang driver options to test debug info and BOLT

Summary:
This is an essential piece of infrastructure for us to be
continuously testing debug info with BOLT. We can't only make changes
to a test repo because we need to change debuginfo tests to call BOLT,
hence, this diff needs to sit in our opensource repo. But when upstreaming
to LLVM, this should be kept BOLT-only outside of LLVM. When upstreaming,
we need to git diff and check all folders that are being modified by our
commits and discard this one (and leave as an internal diff).

To test BOLT in debuginfo tests, configure it with -DLLVM_TEST_BOLT=ON.
Then run check-lldb and check-debuginfo.

Manual rebase conflict history:
https://phabricator.intern.facebook.com/D29205224
https://phabricator.intern.facebook.com/D29564078
https://phabricator.intern.facebook.com/D33289118
https://phabricator.intern.facebook.com/D34957174
https://phabricator.intern.facebook.com/D35317341

Test Plan:
tested locally
Configured with:
-DLLVM_ENABLE_PROJECTS="clang;lld;lldb;compiler-rt;bolt;debuginfo-tests"
-DLLVM_TEST_BOLT=ON
Ran test suite with:
ninja check-debuginfo
ninja check-lldb

Reviewers: maks, #llvm-bolt

Reviewed By: maks

Subscribers: ayermolo, phabricatorlinter

Differential Revision: https://phabricator.intern.facebook.com/D46256657

Tasks: T92898286

Author: aaupov

clang/include/clang/Driver/Options.td

@@ -5561,6 +5561,10 @@ def pg : Flag<["-"], "pg">, HelpText<"Enable mcount instrumentation">,
   MarshallingInfoFlag<CodeGenOpts<"InstrumentForProfiling">>;
 def pipe : Flag<["-", "--"], "pipe">,
   HelpText<"Use pipes between commands, when possible">;
+// Facebook T92898286
+def post_link_optimize : Flag<["--"], "post-link-optimize">,
+  HelpText<"Apply post-link optimizations using BOLT">;
+// End Facebook T92898286
 def prebind__all__twolevel__modules : Flag<["-"], "prebind_all_twolevel_modules">;
 def prebind : Flag<["-"], "prebind">;
 def preload : Flag<["-"], "preload">;

clang/lib/Driver/ToolChains/Gnu.cpp

@@ -672,12 +672,41 @@ void tools::gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
     }
   }
 
+  // Facebook T92898286
+  if (Args.hasArg(options::OPT_post_link_optimize))
+    CmdArgs.push_back("-q");
+  // End Facebook T92898286
+
   Args.AddAllArgs(CmdArgs, options::OPT_T);
 
   const char *Exec = Args.MakeArgString(ToolChain.GetLinkerPath());
   C.addCommand(std::make_unique<Command>(JA, *this,
                                          ResponseFileSupport::AtFileCurCP(),
                                          Exec, CmdArgs, Inputs, Output));
+  // Facebook T92898286
+  if (!Args.hasArg(options::OPT_post_link_optimize) || !Output.isFilename())
+    return;
+
+  const char *MvExec = Args.MakeArgString(ToolChain.GetProgramPath("mv"));
+  ArgStringList MoveCmdArgs;
+  MoveCmdArgs.push_back(Output.getFilename());
+  const char *PreBoltBin =
+      Args.MakeArgString(Twine(Output.getFilename()) + ".pre-bolt");
+  MoveCmdArgs.push_back(PreBoltBin);
+  C.addCommand(std::make_unique<Command>(JA, *this, ResponseFileSupport::None(),
+                                         MvExec, MoveCmdArgs, std::nullopt));
+
+  ArgStringList BoltCmdArgs;
+  const char *BoltExec =
+      Args.MakeArgString(ToolChain.GetProgramPath("llvm-bolt"));
+  BoltCmdArgs.push_back(PreBoltBin);
+  BoltCmdArgs.push_back("-reorder-blocks=reverse");
+  BoltCmdArgs.push_back("-update-debug-sections");
+  BoltCmdArgs.push_back("-o");
+  BoltCmdArgs.push_back(Output.getFilename());
+  C.addCommand(std::make_unique<Command>(JA, *this, ResponseFileSupport::None(),
+                                         BoltExec, BoltCmdArgs, std::nullopt));
+  // End Facebook T92898286
 }
 
 void tools::gnutools::Assembler::ConstructJob(Compilation &C,

cross-project-tests/lit.cfg.py

@@ -81,7 +81,13 @@ def get_required_attr(config, attr_name):
 # use_clang() and use_lld() respectively, so set them to "", if needed.
 if not hasattr(config, "clang_src_dir"):
     config.clang_src_dir = ""
-llvm_config.use_clang(required=("clang" in config.llvm_enabled_projects))
+# Facebook T92898286
+should_test_bolt = get_required_attr(config, "llvm_test_bolt")
+if should_test_bolt:
+    llvm_config.use_clang(required=("clang" in config.llvm_enabled_projects), additional_flags=["--post-link-optimize"])
+else:
+    llvm_config.use_clang(required=("clang" in config.llvm_enabled_projects))
+# End Facebook T92898286
 
 if not hasattr(config, "lld_src_dir"):
     config.lld_src_dir = ""
@@ -294,3 +300,9 @@ def get_clang_default_dwarf_version_string(triple):
 # Allow 'REQUIRES: XXX-registered-target' in tests.
 for arch in config.targets_to_build:
     config.available_features.add(arch.lower() + "-registered-target")
+
+# Facebook T92898286
+# Ensure the user's PYTHONPATH is included.
+if "PYTHONPATH" in os.environ:
+    config.environment["PYTHONPATH"] = os.environ["PYTHONPATH"]
+# End Facebook T92898286

cross-project-tests/lit.site.cfg.py.in

@@ -21,6 +21,10 @@ config.mlir_src_root = "@MLIR_SOURCE_DIR@"
 
 config.llvm_use_sanitizer = "@LLVM_USE_SANITIZER@"
 
+# Facebook T92898286
+config.llvm_test_bolt = lit.util.pythonize_bool("@LLVM_TEST_BOLT@")
+# End Facebook T92898286
+
 import lit.llvm
 lit.llvm.initialize(lit_config, config)
 

lldb/test/API/lit.cfg.py

@@ -265,6 +265,11 @@ def delete_module_cache(path):
 if is_configured("lldb_framework_dir"):
     dotest_cmd += ["--framework", config.lldb_framework_dir]
 
+# Facebook T92898286
+if is_configured("llvm_test_bolt"):
+    dotest_cmd += ["-E", '"--post-link-optimize"']
+# End Facebook T92898286
+
 if (
     "lldb-repro-capture" in config.available_features
     or "lldb-repro-replay" in config.available_features

lldb/test/API/lit.site.cfg.py.in

@@ -1,5 +1,9 @@
 @LIT_SITE_CFG_IN_HEADER@
 
+#Facebook T92898286
+import lit.util
+#End Facebook T92898286
+
 config.llvm_src_root = "@LLVM_SOURCE_DIR@"
 config.llvm_obj_root = "@LLVM_BINARY_DIR@"
 config.llvm_tools_dir = lit_config.substitute("@LLVM_TOOLS_DIR@")
@@ -39,6 +43,10 @@ config.libcxx_include_target_dir = "@LIBCXX_GENERATED_INCLUDE_TARGET_DIR@"
 config.lldb_module_cache = os.path.join("@LLDB_TEST_MODULE_CACHE_LLDB@", "lldb-api")
 config.clang_module_cache = os.path.join("@LLDB_TEST_MODULE_CACHE_CLANG@", "lldb-api")
 
+# Facebook T92898286
+config.llvm_test_bolt = lit.util.pythonize_bool("@LLVM_TEST_BOLT@")
+# End Facebook T92898286
+
 # Plugins
 lldb_build_intel_pt = '@LLDB_BUILD_INTEL_PT@'
 if lldb_build_intel_pt == '1':

lldb/test/Shell/helper/toolchain.py

@@ -165,6 +165,11 @@ def use_support_substitutions(config):
     if config.cmake_sysroot:
         host_flags += ["--sysroot={}".format(config.cmake_sysroot)]
 
+    # Facebook T92898286
+    if config.llvm_test_bolt:
+        host_flags += ["--post-link-optimize"]
+    # End Facebook T92898286
+
     host_flags = " ".join(host_flags)
     config.substitutions.append(("%clang_host", "%clang " + host_flags))
     config.substitutions.append(("%clangxx_host", "%clangxx " + host_flags))

lldb/test/Shell/lit.site.cfg.py.in

@@ -1,5 +1,10 @@
 @LIT_SITE_CFG_IN_HEADER@
 
+#Facebook T92898286
+import lit.util
+#End Facebook T92898286
+
+
 config.llvm_src_root = "@LLVM_SOURCE_DIR@"
 config.llvm_obj_root = "@LLVM_BINARY_DIR@"
 config.llvm_tools_dir = lit_config.substitute("@LLVM_TOOLS_DIR@")
@@ -31,6 +36,10 @@ config.llvm_use_sanitizer = "@LLVM_USE_SANITIZER@"
 config.lldb_module_cache = os.path.join("@LLDB_TEST_MODULE_CACHE_LLDB@", "lldb-shell")
 config.clang_module_cache = os.path.join("@LLDB_TEST_MODULE_CACHE_CLANG@", "lldb-shell")
 
+# Facebook T92898286
+config.llvm_test_bolt = lit.util.pythonize_bool("@LLVM_TEST_BOLT@")
+# End Facebook T92898286
+
 import lit.llvm
 lit.llvm.initialize(lit_config, config)
 

llvm/CMakeLists.txt

@@ -709,6 +709,10 @@ set(LLVM_LIB_FUZZING_ENGINE "" CACHE PATH
 option(LLVM_USE_SPLIT_DWARF
   "Use -gsplit-dwarf when compiling llvm and --gdb-index when linking." OFF)
 
+# Facebook T92898286
+option(LLVM_TEST_BOLT "Enable BOLT testing in non-BOLT tests that use clang" OFF)
+# End Facebook T92898286
+
 # Define an option controlling whether we should build for 32-bit on 64-bit
 # platforms, where supported.
 if( CMAKE_SIZEOF_VOID_P EQUAL 8 AND NOT (WIN32 OR ${CMAKE_SYSTEM_NAME} MATCHES "AIX"))