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-rw-r--r--clang/docs/ReleaseNotes.rst5
-rw-r--r--clang/docs/UsersManual.rst63
-rw-r--r--clang/include/clang/Driver/Options.td5
-rw-r--r--clang/include/clang/Frontend/CodeGenOptions.h4
-rw-r--r--clang/lib/CodeGen/BackendUtil.cpp15
-rw-r--r--clang/lib/CodeGen/CodeGenModule.cpp2
-rw-r--r--clang/lib/Driver/ToolChains/Clang.cpp1
-rw-r--r--clang/lib/Frontend/CompilerInvocation.cpp7
-rw-r--r--clang/test/CodeGenCXX/Inputs/profile-remap.map2
-rw-r--r--clang/test/CodeGenCXX/Inputs/profile-remap.proftext7
-rw-r--r--clang/test/CodeGenCXX/Inputs/profile-remap.samples3
-rw-r--r--clang/test/CodeGenCXX/profile-remap.cpp27
-rw-r--r--clang/test/Driver/clang_f_opts.c2
13 files changed, 137 insertions, 6 deletions
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index b3eb9d5e108..7e798492bb0 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -46,6 +46,11 @@ sections with improvements to Clang's support for those languages.
Major New Features
------------------
+- Clang supports use of a profile remapping file, which permits
+ profile data captured for one version of a program to be applied
+ when building another version where symbols have changed (for
+ example, due to renaming a class or namespace).
+ See the :doc:`UsersManual` for details.
Improvements to Clang's diagnostics
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/docs/UsersManual.rst b/clang/docs/UsersManual.rst
index e0dc31f432f..438ef46a45e 100644
--- a/clang/docs/UsersManual.rst
+++ b/clang/docs/UsersManual.rst
@@ -1799,6 +1799,69 @@ In these cases, you can use the flag ``-fno-profile-instr-generate`` (or
Note that these flags should appear after the corresponding profile
flags to have an effect.
+Profile remapping
+^^^^^^^^^^^^^^^^^
+
+When the program is compiled after a change that affects many symbol names,
+pre-existing profile data may no longer match the program. For example:
+
+ * switching from libstdc++ to libc++ will result in the mangled names of all
+ functions taking standard library types to change
+ * renaming a widely-used type in C++ will result in the mangled names of all
+ functions that have parameters involving that type to change
+ * moving from a 32-bit compilation to a 64-bit compilation may change the
+ underlying type of ``size_t`` and similar types, resulting in changes to
+ manglings
+
+Clang allows use of a profile remapping file to specify that such differences
+in mangled names should be ignored when matching the profile data against the
+program.
+
+.. option:: -fprofile-remapping-file=<file>
+
+ Specifies a file containing profile remapping information, that will be
+ used to match mangled names in the profile data to mangled names in the
+ program.
+
+The profile remapping file is a text file containing lines of the form
+
+.. code-block::
+
+ fragmentkind fragment1 fragment2
+
+where ``fragmentkind`` is one of ``name``, ``type``, or ``encoding``,
+indicating whether the following mangled name fragments are
+<`name <http://itanium-cxx-abi.github.io/cxx-abi/abi.html#mangle.name>`>s,
+<`type <http://itanium-cxx-abi.github.io/cxx-abi/abi.html#mangle.type>`>s, or
+<`encoding <http://itanium-cxx-abi.github.io/cxx-abi/abi.html#mangle.encoding>`>s,
+respectively.
+
+Blank lines and lines starting with ``#`` are ignored.
+
+For example, to specify that ``absl::string_view`` and ``std::string_view``
+should be treated as equivalent when matching profile data, the following
+remapping file could be used:
+
+.. code-block::
+
+ # absl::string_view is considered equivalent to std::string_view
+ type N4absl11string_viewE St17basic_string_viewIcSt11char_traitsIcEE
+
+ # std:: might be std::__1:: in libc++ or std::__cxx11:: in libstdc++
+ name 3std St3__1
+ name 3std St7__cxx11
+
+Matching profile data using a profile remapping file is supported on a
+best-effort basis. For example, information regarding indirect call targets is
+currently not remapped. For best results, you are encouraged to generate new
+profile data matching the updated program.
+
+.. note::
+
+ Profile data remapping is currently only supported for C++ mangled names
+ following the Itanium C++ ABI mangling scheme. This covers all C++ targets
+ supported by Clang other than Windows.
+
Controlling Debug Information
-----------------------------
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index e006187c0e3..166f913211c 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -735,6 +735,11 @@ def fprofile_instr_use : Flag<["-"], "fprofile-instr-use">, Group<f_Group>,
def fprofile_instr_use_EQ : Joined<["-"], "fprofile-instr-use=">,
Group<f_Group>, Flags<[CoreOption]>,
HelpText<"Use instrumentation data for profile-guided optimization">;
+def fprofile_remapping_file_EQ : Joined<["-"], "fprofile-remapping-file=">,
+ Group<f_Group>, Flags<[CC1Option, CoreOption]>, MetaVarName<"<file>">,
+ HelpText<"Use the remappings described in <file> to match the profile data against names in the program">;
+def fprofile_remapping_file : Separate<["-"], "fprofile-remapping-file">,
+ Group<f_Group>, Flags<[CoreOption]>, Alias<fprofile_remapping_file_EQ>;
def fcoverage_mapping : Flag<["-"], "fcoverage-mapping">,
Group<f_Group>, Flags<[CC1Option, CoreOption]>,
HelpText<"Generate coverage mapping to enable code coverage analysis">;
diff --git a/clang/include/clang/Frontend/CodeGenOptions.h b/clang/include/clang/Frontend/CodeGenOptions.h
index d876344a57c..14e6039372a 100644
--- a/clang/include/clang/Frontend/CodeGenOptions.h
+++ b/clang/include/clang/Frontend/CodeGenOptions.h
@@ -200,6 +200,10 @@ public:
/// Name of the profile file to use as input for -fprofile-instr-use
std::string ProfileInstrumentUsePath;
+ /// Name of the profile remapping file to apply to the profile data supplied
+ /// by -fprofile-sample-use or -fprofile-instr-use.
+ std::string ProfileRemappingFile;
+
/// Name of the function summary index file to use for ThinLTO function
/// importing.
std::string ThinLTOIndexFile;
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 45be10f005b..fd9a95b7199 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -930,18 +930,21 @@ void EmitAssemblyHelper::EmitAssemblyWithNewPassManager(
PGOOpt = PGOOptions(CodeGenOpts.InstrProfileOutput.empty()
? DefaultProfileGenName
: CodeGenOpts.InstrProfileOutput,
- "", "", true, CodeGenOpts.DebugInfoForProfiling);
+ "", "", "", true,
+ CodeGenOpts.DebugInfoForProfiling);
else if (CodeGenOpts.hasProfileIRUse())
// -fprofile-use.
- PGOOpt = PGOOptions("", CodeGenOpts.ProfileInstrumentUsePath, "", false,
+ PGOOpt = PGOOptions("", CodeGenOpts.ProfileInstrumentUsePath, "",
+ CodeGenOpts.ProfileRemappingFile, false,
CodeGenOpts.DebugInfoForProfiling);
else if (!CodeGenOpts.SampleProfileFile.empty())
// -fprofile-sample-use
- PGOOpt = PGOOptions("", "", CodeGenOpts.SampleProfileFile, false,
+ PGOOpt = PGOOptions("", "", CodeGenOpts.SampleProfileFile,
+ CodeGenOpts.ProfileRemappingFile, false,
CodeGenOpts.DebugInfoForProfiling);
else if (CodeGenOpts.DebugInfoForProfiling)
// -fdebug-info-for-profiling
- PGOOpt = PGOOptions("", "", "", false, true);
+ PGOOpt = PGOOptions("", "", "", "", false, true);
PassBuilder PB(TM.get(), PGOOpt);
@@ -1130,6 +1133,7 @@ static void runThinLTOBackend(ModuleSummaryIndex *CombinedIndex, Module *M,
const LangOptions &LOpts,
std::unique_ptr<raw_pwrite_stream> OS,
std::string SampleProfile,
+ std::string ProfileRemapping,
BackendAction Action) {
StringMap<DenseMap<GlobalValue::GUID, GlobalValueSummary *>>
ModuleToDefinedGVSummaries;
@@ -1202,6 +1206,7 @@ static void runThinLTOBackend(ModuleSummaryIndex *CombinedIndex, Module *M,
Conf.CGOptLevel = getCGOptLevel(CGOpts);
initTargetOptions(Conf.Options, CGOpts, TOpts, LOpts, HeaderOpts);
Conf.SampleProfile = std::move(SampleProfile);
+ Conf.ProfileRemapping = std::move(ProfileRemapping);
Conf.UseNewPM = CGOpts.ExperimentalNewPassManager;
Conf.DebugPassManager = CGOpts.DebugPassManager;
Conf.RemarksWithHotness = CGOpts.DiagnosticsWithHotness;
@@ -1268,7 +1273,7 @@ void clang::EmitBackendOutput(DiagnosticsEngine &Diags,
if (!CombinedIndex->skipModuleByDistributedBackend()) {
runThinLTOBackend(CombinedIndex.get(), M, HeaderOpts, CGOpts, TOpts,
LOpts, std::move(OS), CGOpts.SampleProfileFile,
- Action);
+ CGOpts.ProfileRemappingFile, Action);
return;
}
// Distributed indexing detected that nothing from the module is needed
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 12ed65cf267..eebf7c23f3b 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -154,7 +154,7 @@ CodeGenModule::CodeGenModule(ASTContext &C, const HeaderSearchOptions &HSO,
if (CodeGenOpts.hasProfileClangUse()) {
auto ReaderOrErr = llvm::IndexedInstrProfReader::create(
- CodeGenOpts.ProfileInstrumentUsePath);
+ CodeGenOpts.ProfileInstrumentUsePath, CodeGenOpts.ProfileRemappingFile);
if (auto E = ReaderOrErr.takeError()) {
unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
"Could not read profile %0: %1");
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 070abd82508..127f8069622 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -4355,6 +4355,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
else
A->render(Args, CmdArgs);
}
+ Args.AddLastArg(CmdArgs, options::OPT_fprofile_remapping_file_EQ);
RenderBuiltinOptions(TC, RawTriple, Args, CmdArgs);
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index e848e50ced4..5dcd23e1ad4 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -657,6 +657,13 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
Args.getLastArgValue(OPT_fprofile_instrument_use_path_EQ);
if (!Opts.ProfileInstrumentUsePath.empty())
setPGOUseInstrumentor(Opts, Opts.ProfileInstrumentUsePath);
+ Opts.ProfileRemappingFile =
+ Args.getLastArgValue(OPT_fprofile_remapping_file_EQ);
+ if (!Opts.ProfileRemappingFile.empty() && !Opts.ExperimentalNewPassManager) {
+ Diags.Report(diag::err_drv_argument_only_allowed_with)
+ << Args.getLastArg(OPT_fprofile_remapping_file_EQ)->getAsString(Args)
+ << "-fexperimental-new-pass-manager";
+ }
Opts.CoverageMapping =
Args.hasFlag(OPT_fcoverage_mapping, OPT_fno_coverage_mapping, false);
diff --git a/clang/test/CodeGenCXX/Inputs/profile-remap.map b/clang/test/CodeGenCXX/Inputs/profile-remap.map
new file mode 100644
index 00000000000..50b812a9165
--- /dev/null
+++ b/clang/test/CodeGenCXX/Inputs/profile-remap.map
@@ -0,0 +1,2 @@
+name 3Foo 3Bar
+type N3Foo1XE N3Baz1YE
diff --git a/clang/test/CodeGenCXX/Inputs/profile-remap.proftext b/clang/test/CodeGenCXX/Inputs/profile-remap.proftext
new file mode 100644
index 00000000000..a1f90cfa6e9
--- /dev/null
+++ b/clang/test/CodeGenCXX/Inputs/profile-remap.proftext
@@ -0,0 +1,7 @@
+:ir
+_ZN3Foo8functionENS_1XE
+29667547796
+2
+10
+90
+
diff --git a/clang/test/CodeGenCXX/Inputs/profile-remap.samples b/clang/test/CodeGenCXX/Inputs/profile-remap.samples
new file mode 100644
index 00000000000..45e599470cc
--- /dev/null
+++ b/clang/test/CodeGenCXX/Inputs/profile-remap.samples
@@ -0,0 +1,3 @@
+_ZN3Bar8functionEN3Baz1YE:100:0
+ 2: 10
+ 4: 90
diff --git a/clang/test/CodeGenCXX/profile-remap.cpp b/clang/test/CodeGenCXX/profile-remap.cpp
new file mode 100644
index 00000000000..e122db10836
--- /dev/null
+++ b/clang/test/CodeGenCXX/profile-remap.cpp
@@ -0,0 +1,27 @@
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -fprofile-sample-use=%S/Inputs/profile-remap.samples -fprofile-remapping-file=%S/Inputs/profile-remap.map -fexperimental-new-pass-manager -O2 %s -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK,CHECK-SAMPLES
+// RUN: llvm-profdata merge -output %T.profdata %S/Inputs/profile-remap.proftext
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -fprofile-instrument-use-path=%T.profdata -fprofile-remapping-file=%S/Inputs/profile-remap.map -fexperimental-new-pass-manager -O2 %s -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK,CHECK-INSTR
+
+namespace Foo {
+ struct X {};
+ bool cond();
+ void bar();
+ void baz();
+ void function(X x) {
+ if (cond())
+ bar();
+ else
+ baz();
+ }
+}
+
+// CHECK: define {{.*}} @_ZN3Foo8functionENS_1XE() {{.*}} !prof [[FUNC_ENTRY:![0-9]*]]
+// CHECK: br i1 {{.*}} !prof [[BR_WEIGHTS:![0-9]*]]
+//
+// FIXME: Laplace's rule of succession is applied to sample profiles...
+// CHECK-SAMPLES-DAG: [[FUNC_ENTRY]] = !{!"function_entry_count", i64 1}
+// CHECK-SAMPLES-DAG: [[BR_WEIGHTS]] = !{!"branch_weights", i32 11, i32 91}
+//
+// ... but not to instruction profiles.
+// CHECK-INSTR-DAG: [[FUNC_ENTRY]] = !{!"function_entry_count", i64 100}
+// CHECK-INSTR-DAG: [[BR_WEIGHTS]] = !{!"branch_weights", i32 10, i32 90}
diff --git a/clang/test/Driver/clang_f_opts.c b/clang/test/Driver/clang_f_opts.c
index f1836980c1c..6536605c4c5 100644
--- a/clang/test/Driver/clang_f_opts.c
+++ b/clang/test/Driver/clang_f_opts.c
@@ -116,6 +116,7 @@
// RUN: %clang -### -S -fcoverage-mapping %s 2>&1 | FileCheck -check-prefix=CHECK-COVERAGE-AND-GEN %s
// RUN: %clang -### -S -fcoverage-mapping -fno-coverage-mapping %s 2>&1 | FileCheck -check-prefix=CHECK-DISABLE-COVERAGE %s
// RUN: %clang -### -S -fprofile-instr-generate -fcoverage-mapping -fno-coverage-mapping %s 2>&1 | FileCheck -check-prefix=CHECK-DISABLE-COVERAGE %s
+// RUN: %clang -### -S -fprofile-remapping-file foo/bar.txt %s 2>&1 | FileCheck -check-prefix=CHECK-PROFILE-REMAP %s
// CHECK-PROFILE-GENERATE: "-fprofile-instrument=clang"
// CHECK-PROFILE-GENERATE-LLVM: "-fprofile-instrument=llvm"
// CHECK-PROFILE-GENERATE-DIR: "-fprofile-instrument-path=/some/dir{{/|\\\\}}{{.*}}"
@@ -126,6 +127,7 @@
// CHECK-DISABLE-USE-NOT: "-fprofile-instr-use"
// CHECK-COVERAGE-AND-GEN: '-fcoverage-mapping' only allowed with '-fprofile-instr-generate'
// CHECK-DISABLE-COVERAGE-NOT: "-fcoverage-mapping"
+// CHECK-PROFILE-REMAP: "-fprofile-remapping-file=foo/bar.txt"
// RUN: %clang -### -S -fprofile-use %s 2>&1 | FileCheck -check-prefix=CHECK-PROFILE-USE %s
// RUN: %clang -### -S -fprofile-instr-use %s 2>&1 | FileCheck -check-prefix=CHECK-PROFILE-USE %s
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