[clang-tools-extra] [clang] [compiler-rt] [PGO] Exposing PGO's Counter Reset and File Dumping APIs (PR #76471)
Qiongsi Wu via cfe-commits
cfe-commits at lists.llvm.org
Thu Dec 28 17:02:15 PST 2023
https://github.com/qiongsiwu updated https://github.com/llvm/llvm-project/pull/76471
>From 6c9381ec324595947237bd25642b03ab40b6a4df Mon Sep 17 00:00:00 2001
From: Qiongsi Wu <qwu at ibm.com>
Date: Wed, 27 Dec 2023 13:05:01 -0500
Subject: [PATCH 1/8] Initial commit
---
.../ExpandModularHeadersPPCallbacks.cpp | 2 +-
clang/include/clang/Frontend/Utils.h | 4 +-
clang/lib/Frontend/CompilerInstance.cpp | 2 +-
clang/lib/Frontend/InitPreprocessor.cpp | 12 ++--
compiler-rt/include/CMakeLists.txt | 1 +
.../include/profile/instr_prof_interface.h | 66 +++++++++++++++++++
compiler-rt/lib/profile/InstrProfiling.h | 32 +--------
7 files changed, 83 insertions(+), 36 deletions(-)
create mode 100644 compiler-rt/include/profile/instr_prof_interface.h
diff --git a/clang-tools-extra/clang-tidy/ExpandModularHeadersPPCallbacks.cpp b/clang-tools-extra/clang-tidy/ExpandModularHeadersPPCallbacks.cpp
index e414ac8c770508..5ecd4fb19131e4 100644
--- a/clang-tools-extra/clang-tidy/ExpandModularHeadersPPCallbacks.cpp
+++ b/clang-tools-extra/clang-tidy/ExpandModularHeadersPPCallbacks.cpp
@@ -100,7 +100,7 @@ ExpandModularHeadersPPCallbacks::ExpandModularHeadersPPCallbacks(
/*OwnsHeaderSearch=*/false);
PP->Initialize(Compiler.getTarget(), Compiler.getAuxTarget());
InitializePreprocessor(*PP, *PO, Compiler.getPCHContainerReader(),
- Compiler.getFrontendOpts());
+ Compiler.getFrontendOpts(), Compiler.getCodeGenOpts());
ApplyHeaderSearchOptions(*HeaderInfo, *HSO, LangOpts,
Compiler.getTarget().getTriple());
}
diff --git a/clang/include/clang/Frontend/Utils.h b/clang/include/clang/Frontend/Utils.h
index 143cf4359f00b5..604e42067a3f1e 100644
--- a/clang/include/clang/Frontend/Utils.h
+++ b/clang/include/clang/Frontend/Utils.h
@@ -43,12 +43,14 @@ class PCHContainerReader;
class Preprocessor;
class PreprocessorOptions;
class PreprocessorOutputOptions;
+class CodeGenOptions;
/// InitializePreprocessor - Initialize the preprocessor getting it and the
/// environment ready to process a single file.
void InitializePreprocessor(Preprocessor &PP, const PreprocessorOptions &PPOpts,
const PCHContainerReader &PCHContainerRdr,
- const FrontendOptions &FEOpts);
+ const FrontendOptions &FEOpts,
+ const CodeGenOptions &CodeGenOpts);
/// DoPrintPreprocessedInput - Implement -E mode.
void DoPrintPreprocessedInput(Preprocessor &PP, raw_ostream *OS,
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index 56bbef9697b650..ea44a26b6db7da 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -470,7 +470,7 @@ void CompilerInstance::createPreprocessor(TranslationUnitKind TUKind) {
// Predefine macros and configure the preprocessor.
InitializePreprocessor(*PP, PPOpts, getPCHContainerReader(),
- getFrontendOpts());
+ getFrontendOpts(), getCodeGenOpts());
// Initialize the header search object. In CUDA compilations, we use the aux
// triple (the host triple) to initialize our header search, since we need to
diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index d83128adb511ef..009a67eea1eb52 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -1366,10 +1366,11 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
/// InitializePreprocessor - Initialize the preprocessor getting it and the
/// environment ready to process a single file.
-void clang::InitializePreprocessor(
- Preprocessor &PP, const PreprocessorOptions &InitOpts,
- const PCHContainerReader &PCHContainerRdr,
- const FrontendOptions &FEOpts) {
+void clang::InitializePreprocessor(Preprocessor &PP,
+ const PreprocessorOptions &InitOpts,
+ const PCHContainerReader &PCHContainerRdr,
+ const FrontendOptions &FEOpts,
+ const CodeGenOptions &CodeGenOpts) {
const LangOptions &LangOpts = PP.getLangOpts();
std::string PredefineBuffer;
PredefineBuffer.reserve(4080);
@@ -1416,6 +1417,9 @@ void clang::InitializePreprocessor(
InitializeStandardPredefinedMacros(PP.getTargetInfo(), PP.getLangOpts(),
FEOpts, Builder);
+ if (CodeGenOpts.hasProfileIRInstr())
+ Builder.defineMacro("__LLVM_INSTR_PROFILE_GENERATE");
+
// Add on the predefines from the driver. Wrap in a #line directive to report
// that they come from the command line.
Builder.append("# 1 \"<command line>\" 1");
diff --git a/compiler-rt/include/CMakeLists.txt b/compiler-rt/include/CMakeLists.txt
index 78427beedb3cc4..7a100c66bbcfda 100644
--- a/compiler-rt/include/CMakeLists.txt
+++ b/compiler-rt/include/CMakeLists.txt
@@ -44,6 +44,7 @@ endif(COMPILER_RT_BUILD_ORC)
if (COMPILER_RT_BUILD_PROFILE)
set(PROFILE_HEADERS
profile/InstrProfData.inc
+ profile/instr_prof_interface.h
)
endif(COMPILER_RT_BUILD_PROFILE)
diff --git a/compiler-rt/include/profile/instr_prof_interface.h b/compiler-rt/include/profile/instr_prof_interface.h
new file mode 100644
index 00000000000000..6cbf6b414f3af1
--- /dev/null
+++ b/compiler-rt/include/profile/instr_prof_interface.h
@@ -0,0 +1,66 @@
+/*===---- instr_profiling.h - Instrumentation PGO User Program API ----------===
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+ *===-----------------------------------------------------------------------===
+ *
+ * This header provides a public interface for user programs to provide
+ * fine-grained control of profile dumping.
+ *
+\*===---------------------------------------------------------------------===*/
+
+#ifndef COMPILER_RT_INSTR_PROFILING
+#define COMPILER_RT_INSTR_PROFILING
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef __LLVM_INSTR_PROFILE_GENERATE
+// Profile file reset and dump interfaces.
+// Only defined when `-fprofile-generate` is in effect.
+
+/*!
+ * \brief Interface to set all PGO counters to zero for the current process.
+ *
+ */
+void __llvm_profile_reset_counters(void);
+
+/*!
+ * \brief this is a wrapper interface to \c __llvm_profile_write_file.
+ * After this interface is invoked, an already dumped flag will be set
+ * so that profile won't be dumped again during program exit.
+ * Invocation of interface __llvm_profile_reset_counters will clear
+ * the flag. This interface is designed to be used to collect profile
+ * data from user selected hot regions. The use model is
+ * __llvm_profile_reset_counters();
+ * ... hot region 1
+ * __llvm_profile_dump();
+ * .. some other code
+ * __llvm_profile_reset_counters();
+ * ... hot region 2
+ * __llvm_profile_dump();
+ *
+ * It is expected that on-line profile merging is on with \c %m specifier
+ * used in profile filename . If merging is not turned on, user is expected
+ * to invoke __llvm_profile_set_filename to specify different profile names
+ * for different regions before dumping to avoid profile write clobbering.
+ */
+int __llvm_profile_dump(void);
+
+// Interface to dump the current process' order file to disk.
+int __llvm_orderfile_dump(void);
+
+#else
+#define __llvm_profile_reset_counters()
+#define __llvm_profile_dump()
+#define __llvm_orderfile_dump()
+#endif
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif
diff --git a/compiler-rt/lib/profile/InstrProfiling.h b/compiler-rt/lib/profile/InstrProfiling.h
index 137115996748ce..3f2c75b5df9064 100644
--- a/compiler-rt/lib/profile/InstrProfiling.h
+++ b/compiler-rt/lib/profile/InstrProfiling.h
@@ -12,6 +12,9 @@
#include "InstrProfilingPort.h"
#include <stdio.h>
+#define __LLVM_INSTR_PROFILE_GENERATE
+#include "profile/instr_prof_interface.h"
+
#define INSTR_PROF_VISIBILITY COMPILER_RT_VISIBILITY
#include "profile/InstrProfData.inc"
@@ -100,12 +103,6 @@ ValueProfNode *__llvm_profile_begin_vnodes();
ValueProfNode *__llvm_profile_end_vnodes();
uint32_t *__llvm_profile_begin_orderfile();
-/*!
- * \brief Clear profile counters to zero.
- *
- */
-void __llvm_profile_reset_counters(void);
-
/*!
* \brief Merge profile data from buffer.
*
@@ -156,29 +153,6 @@ void __llvm_profile_instrument_target_value(uint64_t TargetValue, void *Data,
int __llvm_profile_write_file(void);
int __llvm_orderfile_write_file(void);
-/*!
- * \brief this is a wrapper interface to \c __llvm_profile_write_file.
- * After this interface is invoked, an already dumped flag will be set
- * so that profile won't be dumped again during program exit.
- * Invocation of interface __llvm_profile_reset_counters will clear
- * the flag. This interface is designed to be used to collect profile
- * data from user selected hot regions. The use model is
- * __llvm_profile_reset_counters();
- * ... hot region 1
- * __llvm_profile_dump();
- * .. some other code
- * __llvm_profile_reset_counters();
- * ... hot region 2
- * __llvm_profile_dump();
- *
- * It is expected that on-line profile merging is on with \c %m specifier
- * used in profile filename . If merging is not turned on, user is expected
- * to invoke __llvm_profile_set_filename to specify different profile names
- * for different regions before dumping to avoid profile write clobbering.
- */
-int __llvm_profile_dump(void);
-
-int __llvm_orderfile_dump(void);
/*!
* \brief Set the filename for writing instrumentation data.
>From a6c3b4619ea93cec2be962c60181985a379f8553 Mon Sep 17 00:00:00 2001
From: Qiongsi Wu <qwu at ibm.com>
Date: Wed, 27 Dec 2023 14:02:16 -0500
Subject: [PATCH 2/8] Frontend minor cleanup and adding a test
---
clang/include/clang/Basic/CodeGenOptions.h | 6 ++++++
clang/lib/Frontend/InitPreprocessor.cpp | 12 ++++++++++--
clang/test/Preprocessor/pgo-init.c | 5 +++++
3 files changed, 21 insertions(+), 2 deletions(-)
create mode 100644 clang/test/Preprocessor/pgo-init.c
diff --git a/clang/include/clang/Basic/CodeGenOptions.h b/clang/include/clang/Basic/CodeGenOptions.h
index 6952b48e898a81..e06f1094784caf 100644
--- a/clang/include/clang/Basic/CodeGenOptions.h
+++ b/clang/include/clang/Basic/CodeGenOptions.h
@@ -494,6 +494,12 @@ class CodeGenOptions : public CodeGenOptionsBase {
return getProfileInstr() == ProfileCSIRInstr;
}
+ /// Check if any form of instrumentation is on.
+ bool hasProfileInstr() const {
+ return hasProfileClangInstr() || hasProfileIRInstr() ||
+ hasProfileCSIRInstr();
+ }
+
/// Check if Clang profile use is on.
bool hasProfileClangUse() const {
return getProfileUse() == ProfileClangInstr;
diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 009a67eea1eb52..0386a75ac429fa 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -1364,6 +1364,12 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
TI.getTargetDefines(LangOpts, Builder);
}
+static void InitializePGOProfileMacros(const CodeGenOptions &CodeGenOpts,
+ MacroBuilder &Builder) {
+ if (CodeGenOpts.hasProfileInstr())
+ Builder.defineMacro("__LLVM_INSTR_PROFILE_GENERATE");
+}
+
/// InitializePreprocessor - Initialize the preprocessor getting it and the
/// environment ready to process a single file.
void clang::InitializePreprocessor(Preprocessor &PP,
@@ -1417,8 +1423,10 @@ void clang::InitializePreprocessor(Preprocessor &PP,
InitializeStandardPredefinedMacros(PP.getTargetInfo(), PP.getLangOpts(),
FEOpts, Builder);
- if (CodeGenOpts.hasProfileIRInstr())
- Builder.defineMacro("__LLVM_INSTR_PROFILE_GENERATE");
+ // The PGO instrumentation profile macros are driven by options
+ // -fprofile[-instr]-generate/-fcs-profile-generate/-fprofile[-instr]-use,
+ // hence they are not guarded by InitOpts.UsePredefines.
+ InitializePGOProfileMacros(CodeGenOpts, Builder);
// Add on the predefines from the driver. Wrap in a #line directive to report
// that they come from the command line.
diff --git a/clang/test/Preprocessor/pgo-init.c b/clang/test/Preprocessor/pgo-init.c
new file mode 100644
index 00000000000000..6ac28708fddf71
--- /dev/null
+++ b/clang/test/Preprocessor/pgo-init.c
@@ -0,0 +1,5 @@
+// RUN: %clang -fprofile-generate -E -dM %s | FileCheck -match-full-lines -check-prefix=PROFGEN %s
+// RUN: %clang -fprofile-instr-generate -E -dM %s | FileCheck -match-full-lines -check-prefix=PROFGEN %s
+// RUN: %clang -fcs-profile-generate -E -dM %s | FileCheck -match-full-lines -check-prefix=PROFGEN %s
+//
+// PROFGEN:#define __LLVM_INSTR_PROFILE_GENERATE 1
>From 18ec4ac08a08473f146e842dbeefbe7171ce3eec Mon Sep 17 00:00:00 2001
From: Qiongsi Wu <qwu at ibm.com>
Date: Wed, 27 Dec 2023 16:01:22 -0500
Subject: [PATCH 3/8] Refactoring tests, adding profile-use macro
---
clang/lib/Frontend/InitPreprocessor.cpp | 3 +++
clang/test/Preprocessor/pgo-init.c | 5 -----
clang/test/Profile/c-general.c | 9 ++++++++
compiler-rt/test/profile/instrprof-api.c | 26 ++++++++++++++++++++++++
4 files changed, 38 insertions(+), 5 deletions(-)
delete mode 100644 clang/test/Preprocessor/pgo-init.c
create mode 100644 compiler-rt/test/profile/instrprof-api.c
diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 0386a75ac429fa..fe0fd3614113c4 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -1368,6 +1368,9 @@ static void InitializePGOProfileMacros(const CodeGenOptions &CodeGenOpts,
MacroBuilder &Builder) {
if (CodeGenOpts.hasProfileInstr())
Builder.defineMacro("__LLVM_INSTR_PROFILE_GENERATE");
+
+ if (CodeGenOpts.hasProfileIRUse() || CodeGenOpts.hasProfileClangUse())
+ Builder.defineMacro("__LLVM_INSTR_PROFILE_USE");
}
/// InitializePreprocessor - Initialize the preprocessor getting it and the
diff --git a/clang/test/Preprocessor/pgo-init.c b/clang/test/Preprocessor/pgo-init.c
deleted file mode 100644
index 6ac28708fddf71..00000000000000
--- a/clang/test/Preprocessor/pgo-init.c
+++ /dev/null
@@ -1,5 +0,0 @@
-// RUN: %clang -fprofile-generate -E -dM %s | FileCheck -match-full-lines -check-prefix=PROFGEN %s
-// RUN: %clang -fprofile-instr-generate -E -dM %s | FileCheck -match-full-lines -check-prefix=PROFGEN %s
-// RUN: %clang -fcs-profile-generate -E -dM %s | FileCheck -match-full-lines -check-prefix=PROFGEN %s
-//
-// PROFGEN:#define __LLVM_INSTR_PROFILE_GENERATE 1
diff --git a/clang/test/Profile/c-general.c b/clang/test/Profile/c-general.c
index b841f9c3d2a1d1..fa9eb7ebc78274 100644
--- a/clang/test/Profile/c-general.c
+++ b/clang/test/Profile/c-general.c
@@ -9,6 +9,15 @@
// Also check compatibility with older profiles.
// RUN: %clang_cc1 -triple x86_64-apple-macosx10.9 -main-file-name c-general.c %s -o - -emit-llvm -fprofile-instrument-use-path=%S/Inputs/c-general.profdata.v1 | FileCheck -allow-deprecated-dag-overlap -check-prefix=PGOUSE %s
+// RUN: %clang -fprofile-generate -E -dM %s | FileCheck -match-full-lines -check-prefix=PROFGENMACRO %s
+// RUN: %clang -fprofile-instr-generate -E -dM %s | FileCheck -match-full-lines -check-prefix=PROFGENMACRO %s
+// RUN: %clang -fcs-profile-generate -E -dM %s | FileCheck -match-full-lines -check-prefix=PROFGENMACRO %s
+//
+// RUN: %clang -fprofile-use=%t.profdata -E -dM %s | FileCheck -match-full-lines -check-prefix=PROFUSEMACRO %s
+
+// PROFGENMACRO:#define __LLVM_INSTR_PROFILE_GENERATE 1
+// PROFUSEMACRO:#define __LLVM_INSTR_PROFILE_USE 1
+
// PGOGEN: @[[SLC:__profc_simple_loops]] = private global [4 x i64] zeroinitializer
// PGOGEN: @[[IFC:__profc_conditionals]] = private global [13 x i64] zeroinitializer
// PGOGEN: @[[EEC:__profc_early_exits]] = private global [9 x i64] zeroinitializer
diff --git a/compiler-rt/test/profile/instrprof-api.c b/compiler-rt/test/profile/instrprof-api.c
new file mode 100644
index 00000000000000..600fbb575feea3
--- /dev/null
+++ b/compiler-rt/test/profile/instrprof-api.c
@@ -0,0 +1,26 @@
+// RUN: %clang_profgen %s -S -emit-llvm -o - | FileCheck %s --check-prefix=PROFGEN
+// RUN: %clang_profgen -o %t %s
+// RUN: env LLVM_PROFILE_FILE=%t.profraw %run %t
+// RUN: llvm-profdata merge -o %t.profdata %t.profraw
+// RUN: %clang_profuse=%t.profdata %s -S -emit-llvm -o - | FileCheck %s --check-prefix=PROFUSE
+#include "profile/instr_profiling.h"
+
+__attribute__((noinline)) int bar() { return 4; }
+
+int foo() {
+ __llvm_profile_reset_counters();
+ // PROFGEN: call void @__llvm_profile_reset_counters()
+ // PROFUSE-NOT: call void @__llvm_profile_reset_counters()
+ return bar();
+}
+
+int main() {
+ int z = foo() + 3;
+ __llvm_profile_dump();
+ // PROFGEN: %call1 = call signext i32 @__llvm_profile_dump()
+ // PROFUSE-NOT: %call1 = call signext i32 @__llvm_profile_dump()
+ __llvm_orderfile_dump();
+ // PROFGEN: %call2 = call signext i32 @__llvm_orderfile_dump()
+ // PROFUSE-NOT: %call2 = call signext i32 @__llvm_orderfile_dump()
+ return z + bar() - 11;
+}
>From b741a557715eb17b69fa5b4013f2efeadcb80fda Mon Sep 17 00:00:00 2001
From: Qiongsi Wu <qwu at ibm.com>
Date: Wed, 27 Dec 2023 16:08:25 -0500
Subject: [PATCH 4/8] Fix header comment
---
compiler-rt/include/profile/instr_prof_interface.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/compiler-rt/include/profile/instr_prof_interface.h b/compiler-rt/include/profile/instr_prof_interface.h
index 6cbf6b414f3af1..7d0516e5f6eaec 100644
--- a/compiler-rt/include/profile/instr_prof_interface.h
+++ b/compiler-rt/include/profile/instr_prof_interface.h
@@ -1,4 +1,4 @@
-/*===---- instr_profiling.h - Instrumentation PGO User Program API ----------===
+/*===---- instr_prof_interface.h - Instrumentation PGO User Program API ----===
*
* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
* See https://llvm.org/LICENSE.txt for license information.
@@ -7,7 +7,7 @@
*===-----------------------------------------------------------------------===
*
* This header provides a public interface for user programs to provide
- * fine-grained control of profile dumping.
+ * fine-grained control of counter reset and profile dumping.
*
\*===---------------------------------------------------------------------===*/
>From 13a4bb39165df84668b6958cecf6aa46a1235731 Mon Sep 17 00:00:00 2001
From: Qiongsi Wu <qwu at ibm.com>
Date: Wed, 27 Dec 2023 16:42:04 -0500
Subject: [PATCH 5/8] Fix test case after header renaming.
---
compiler-rt/test/profile/instrprof-api.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/compiler-rt/test/profile/instrprof-api.c b/compiler-rt/test/profile/instrprof-api.c
index 600fbb575feea3..8d21dca69a5d60 100644
--- a/compiler-rt/test/profile/instrprof-api.c
+++ b/compiler-rt/test/profile/instrprof-api.c
@@ -3,7 +3,7 @@
// RUN: env LLVM_PROFILE_FILE=%t.profraw %run %t
// RUN: llvm-profdata merge -o %t.profdata %t.profraw
// RUN: %clang_profuse=%t.profdata %s -S -emit-llvm -o - | FileCheck %s --check-prefix=PROFUSE
-#include "profile/instr_profiling.h"
+#include "profile/instr_prof_interface.h"
__attribute__((noinline)) int bar() { return 4; }
>From cce25f062c00424c153254fc159309808441414c Mon Sep 17 00:00:00 2001
From: Qiongsi Wu <qwu at ibm.com>
Date: Wed, 27 Dec 2023 18:25:14 -0500
Subject: [PATCH 6/8] Address review comments
---
compiler-rt/include/profile/instr_prof_interface.h | 4 ++--
compiler-rt/lib/profile/InstrProfiling.h | 10 ++++++++++
compiler-rt/test/profile/instrprof-api.c | 6 ++++--
3 files changed, 16 insertions(+), 4 deletions(-)
diff --git a/compiler-rt/include/profile/instr_prof_interface.h b/compiler-rt/include/profile/instr_prof_interface.h
index 7d0516e5f6eaec..4905b913503dff 100644
--- a/compiler-rt/include/profile/instr_prof_interface.h
+++ b/compiler-rt/include/profile/instr_prof_interface.h
@@ -55,8 +55,8 @@ int __llvm_orderfile_dump(void);
#else
#define __llvm_profile_reset_counters()
-#define __llvm_profile_dump()
-#define __llvm_orderfile_dump()
+#define __llvm_profile_dump() (0)
+#define __llvm_orderfile_dump() (0)
#endif
#ifdef __cplusplus
diff --git a/compiler-rt/lib/profile/InstrProfiling.h b/compiler-rt/lib/profile/InstrProfiling.h
index 3f2c75b5df9064..f921c361c17e2b 100644
--- a/compiler-rt/lib/profile/InstrProfiling.h
+++ b/compiler-rt/lib/profile/InstrProfiling.h
@@ -12,8 +12,18 @@
#include "InstrProfilingPort.h"
#include <stdio.h>
+// Make sure __LLVM_INSTR_PROFILE_GENERATE is always defined before
+// including instr_prof_interface.h so the interface functions are
+// declared correctly for the runtime. Additionally, make sure
+// that __LLVM_INSTR_PROFILE_GENERATE is undefined only when it is
+// not explicitly defined somewhere else.
+#ifndef __LLVM_INSTR_PROFILE_GENERATE
#define __LLVM_INSTR_PROFILE_GENERATE
#include "profile/instr_prof_interface.h"
+#undef __LLVM_INSTR_PROFILE_GENERATE
+#else
+#include "profile/instr_prof_interface.h"
+#endif
#define INSTR_PROF_VISIBILITY COMPILER_RT_VISIBILITY
#include "profile/InstrProfData.inc"
diff --git a/compiler-rt/test/profile/instrprof-api.c b/compiler-rt/test/profile/instrprof-api.c
index 8d21dca69a5d60..894e4b92e8348d 100644
--- a/compiler-rt/test/profile/instrprof-api.c
+++ b/compiler-rt/test/profile/instrprof-api.c
@@ -1,8 +1,10 @@
-// RUN: %clang_profgen %s -S -emit-llvm -o - | FileCheck %s --check-prefix=PROFGEN
+// RUN: %clang_profgen %s --target=ppc64le-unknown-linux-gnu -S \
+// RUN: -emit-llvm -o - | FileCheck %s --check-prefix=PROFGEN
// RUN: %clang_profgen -o %t %s
// RUN: env LLVM_PROFILE_FILE=%t.profraw %run %t
// RUN: llvm-profdata merge -o %t.profdata %t.profraw
-// RUN: %clang_profuse=%t.profdata %s -S -emit-llvm -o - | FileCheck %s --check-prefix=PROFUSE
+// RUN: %clang_profuse=%t.profdata %s --target=ppc64le-unknown-linux-gnu -S \
+// RUN: -emit-llvm -o - | FileCheck %s --check-prefix=PROFUSE
#include "profile/instr_prof_interface.h"
__attribute__((noinline)) int bar() { return 4; }
>From ec4786808381b1a85e051d034408c8009290d8b4 Mon Sep 17 00:00:00 2001
From: Qiongsi Wu <qwu at ibm.com>
Date: Thu, 28 Dec 2023 09:40:08 -0500
Subject: [PATCH 7/8] Adding a new test to cover weak symbols. Adding a new
interface function to support setting profile file name.
---
.../include/profile/instr_prof_interface.h | 34 ++++++++++++++++---
compiler-rt/lib/profile/InstrProfiling.h | 21 ------------
.../profile/Linux/instrprof-weak-symbol.c | 17 ++++++++++
compiler-rt/test/profile/instrprof-api.c | 12 ++++++-
4 files changed, 58 insertions(+), 26 deletions(-)
create mode 100644 compiler-rt/test/profile/Linux/instrprof-weak-symbol.c
diff --git a/compiler-rt/include/profile/instr_prof_interface.h b/compiler-rt/include/profile/instr_prof_interface.h
index 4905b913503dff..06f31210d73bea 100644
--- a/compiler-rt/include/profile/instr_prof_interface.h
+++ b/compiler-rt/include/profile/instr_prof_interface.h
@@ -6,8 +6,9 @@
*
*===-----------------------------------------------------------------------===
*
- * This header provides a public interface for user programs to provide
- * fine-grained control of counter reset and profile dumping.
+ * This header provides a public interface for fine-grained control of counter
+ * reset and profile dumping. These interface functions can be directly called
+ * in user programs.
*
\*===---------------------------------------------------------------------===*/
@@ -20,7 +21,29 @@ extern "C" {
#ifdef __LLVM_INSTR_PROFILE_GENERATE
// Profile file reset and dump interfaces.
-// Only defined when `-fprofile-generate` is in effect.
+// When `-fprofile[-instr]-generate`/`-fcs-profile-generate` is in effect,
+// clang defines __LLVM_INSTR_PROFILE_GENERATE to pick up the API calls.
+
+/*!
+ * \brief Set the filename for writing instrumentation data.
+ *
+ * Sets the filename to be used for subsequent calls to
+ * \a __llvm_profile_write_file().
+ *
+ * \c Name is not copied, so it must remain valid. Passing NULL resets the
+ * filename logic to the default behaviour.
+ *
+ * Note: There may be multiple copies of the profile runtime (one for each
+ * instrumented image/DSO). This API only modifies the filename within the
+ * copy of the runtime available to the calling image.
+ *
+ * Warning: This is a no-op if continuous mode (\ref
+ * __llvm_profile_is_continuous_mode_enabled) is on. The reason for this is
+ * that in continuous mode, profile counters are mmap()'d to the profile at
+ * program initialization time. Support for transferring the mmap'd profile
+ * counts to a new file has not been implemented.
+ */
+void __llvm_profile_set_filename(const char *Name);
/*!
* \brief Interface to set all PGO counters to zero for the current process.
@@ -40,7 +63,7 @@ void __llvm_profile_reset_counters(void);
* __llvm_profile_dump();
* .. some other code
* __llvm_profile_reset_counters();
- * ... hot region 2
+ * ... hot region 2
* __llvm_profile_dump();
*
* It is expected that on-line profile merging is on with \c %m specifier
@@ -54,9 +77,12 @@ int __llvm_profile_dump(void);
int __llvm_orderfile_dump(void);
#else
+
+#define __llvm_profile_set_filename(Name)
#define __llvm_profile_reset_counters()
#define __llvm_profile_dump() (0)
#define __llvm_orderfile_dump() (0)
+
#endif
#ifdef __cplusplus
diff --git a/compiler-rt/lib/profile/InstrProfiling.h b/compiler-rt/lib/profile/InstrProfiling.h
index f921c361c17e2b..2210e048210637 100644
--- a/compiler-rt/lib/profile/InstrProfiling.h
+++ b/compiler-rt/lib/profile/InstrProfiling.h
@@ -164,27 +164,6 @@ int __llvm_profile_write_file(void);
int __llvm_orderfile_write_file(void);
-/*!
- * \brief Set the filename for writing instrumentation data.
- *
- * Sets the filename to be used for subsequent calls to
- * \a __llvm_profile_write_file().
- *
- * \c Name is not copied, so it must remain valid. Passing NULL resets the
- * filename logic to the default behaviour.
- *
- * Note: There may be multiple copies of the profile runtime (one for each
- * instrumented image/DSO). This API only modifies the filename within the
- * copy of the runtime available to the calling image.
- *
- * Warning: This is a no-op if continuous mode (\ref
- * __llvm_profile_is_continuous_mode_enabled) is on. The reason for this is
- * that in continuous mode, profile counters are mmap()'d to the profile at
- * program initialization time. Support for transferring the mmap'd profile
- * counts to a new file has not been implemented.
- */
-void __llvm_profile_set_filename(const char *Name);
-
/*!
* \brief Set the FILE object for writing instrumentation data. Return 0 if set
* successfully or return 1 if failed.
diff --git a/compiler-rt/test/profile/Linux/instrprof-weak-symbol.c b/compiler-rt/test/profile/Linux/instrprof-weak-symbol.c
new file mode 100644
index 00000000000000..88292974bdada3
--- /dev/null
+++ b/compiler-rt/test/profile/Linux/instrprof-weak-symbol.c
@@ -0,0 +1,17 @@
+// RUN: %clang_pgogen -o %t %s
+// RUN: not %t
+// RUN: %clang -o %t %s
+// RUN: %t
+
+__attribute__((weak)) void __llvm_profile_reset_counters(void);
+
+__attribute__((noinline)) int bar() { return 4; }
+int foo() {
+ if (__llvm_profile_reset_counters) {
+ __llvm_profile_reset_counters();
+ return 0;
+ }
+ return bar();
+}
+
+int main() { return foo() - 4; }
diff --git a/compiler-rt/test/profile/instrprof-api.c b/compiler-rt/test/profile/instrprof-api.c
index 894e4b92e8348d..8b235f7b5e674c 100644
--- a/compiler-rt/test/profile/instrprof-api.c
+++ b/compiler-rt/test/profile/instrprof-api.c
@@ -16,9 +16,15 @@ int foo() {
return bar();
}
+// PROFUSE-NOT: declare void @__llvm_profile_reset_counters()
+
int main() {
int z = foo() + 3;
- __llvm_profile_dump();
+ __llvm_profile_set_filename("rawprof.profraw");
+ // PROFGEN: call void @__llvm_profile_set_filename(ptr noundef @.str)
+ // PROFUSE-NOT: call void @__llvm_profile_set_filename(ptr noundef @.str)
+ if (__llvm_profile_dump())
+ return 2;
// PROFGEN: %call1 = call signext i32 @__llvm_profile_dump()
// PROFUSE-NOT: %call1 = call signext i32 @__llvm_profile_dump()
__llvm_orderfile_dump();
@@ -26,3 +32,7 @@ int main() {
// PROFUSE-NOT: %call2 = call signext i32 @__llvm_orderfile_dump()
return z + bar() - 11;
}
+
+// PROFUSE-NOT: declare void @__llvm_profile_set_filename(ptr noundef)
+// PROFUSE-NOT: declare signext i32 @__llvm_profile_dump()
+// PROFUSE-NOT: declare signext i32 @__llvm_orderfile_dump()
>From 29086fc6a28be54999afab4787eeaf9334e40b5c Mon Sep 17 00:00:00 2001
From: Qiongsi Wu <qwu at ibm.com>
Date: Thu, 28 Dec 2023 20:02:00 -0500
Subject: [PATCH 8/8] Address code review
---
clang/docs/UsersManual.rst | 91 +++++++++++++++++++
clang/test/Profile/c-general.c | 1 +
compiler-rt/lib/profile/InstrProfiling.h | 10 +-
.../profile/Linux/instrprof-weak-symbol.c | 9 +-
4 files changed, 99 insertions(+), 12 deletions(-)
diff --git a/clang/docs/UsersManual.rst b/clang/docs/UsersManual.rst
index 7c30570437e8b0..82add00423a026 100644
--- a/clang/docs/UsersManual.rst
+++ b/clang/docs/UsersManual.rst
@@ -2809,6 +2809,97 @@ indexed format, regardeless whether it is produced by frontend or the IR pass.
overhead. ``prefer-atomic`` will be transformed to ``atomic`` when supported
by the target, or ``single`` otherwise.
+Fine Tuning Profile Collection
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+The PGO infrastructure provides user program knobs to fine tune profile
+collection. Specifically, the PGO runtime provides the following functions
+that can be used to control the regions in the program where profiles should
+be collected.
+
+ * ``void __llvm_profile_set_filename(const char *Name)``: changes the name of
+ the profile file to ``Name``.
+ * ``void __llvm_profile_reset_counters(void)``: resets all counters to zero.
+ * ``int __llvm_profile_dump(void)``: write the profile data to disk.
+ * ``int __llvm_orderfile_dump(void)``: write the order file to disk.
+
+For example, the following pattern can be used to skip profiling program
+initialization, profile two specific hot regions, and skip profiling program
+cleanup:
+
+.. code-block:: c
+ int main() {
+ initialize();
+
+ // Reset all profile counters to 0 to omit profile collected during
+ // initialize()'s execution.
+ __llvm_profile_reset_counters();
+ ... hot region 1
+ // Dump the profile for hot region 1.
+ __llvm_profile_set_filename("region1.profraw");
+ __llvm_profile_dump();
+
+ // Reset counters before proceeding to hot region 2.
+ __llvm_profile_reset_counters();
+ ... hot region 2
+ // Dump the profile for hot region 2.
+ __llvm_profile_set_filename("region2.profraw");
+ __llvm_profile_dump();
+
+ // Since the profile has been dumped, no further profile data
+ // will be collected beyond the above __llvm_profile_dump().
+ cleanup();
+ return 0;
+ }
+
+These APIs' names can be introduced to user programs in two ways.
+They can be declared as weak symbols on platforms which support
+treating weak symbols as ``null`` during linking. For example, the user can
+have
+
+.. code-block:: c
+ __attribute__((weak)) int __llvm_profile_dump(void);
+
+ // Then later in the same source file
+ if (__llvm_profile_dump)
+ if (__llvm_profile_dump() != 0) { ... }
+ // The first if condition tests if the symbol is actually defined.
+ // Profile dumping only happens if the symbol is defined. Hence,
+ // the user program works correctly during normal (not profile-generate)
+ // executions.
+
+Alternatively, the user program can include the header
+``profile/instr_prof_interface.h``, which contains the API names. For example,
+
+.. code-block:: c
+ #include "profile/instr_prof_interface.h"
+
+ // Then later in the same source file
+ if (__llvm_profile_dump() != 0) { ... }
+
+The user code does not need to check if the API names are defined, because
+these names are automatically replaced by ``(0)`` or the equivalence of noop
+if the ``clang`` is not compiling for profile generation.
+
+Such replacement can happen because ``clang`` adds one of two macros depending
+on the ``-fprofile-generate`` and the ``-fprofile-use`` flags.
+
+ * ``__LLVM_INSTR_PROFILE_GENERATE``: defined when one of
+ ``-fprofile[-instr]-generate``/``-fcs-profile-generate`` is in effect.
+ * ``__LLVM_INSTR_PROFILE_USE``: defined when one of
+ ``-fprofile-use``/``-fprofile-instr-use`` is in effect.
+
+The two macros can be used to provide more flexibiilty so a user program
+can execute code specifically intended for profile generate or profile use.
+For example, a user program can have special logging during profile generate:
+
+.. code-block:: c
+ #if __LLVM_INSTR_PROFILE_GENERATE
+ expensive_logging_of_full_program_state();
+ #endif
+
+The logging is automatically excluded during a normal build of the program,
+hence it does not impact performance during a normal execution.
+
Disabling Instrumentation
^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/test/Profile/c-general.c b/clang/test/Profile/c-general.c
index fa9eb7ebc78274..2f621ec9b0bf9d 100644
--- a/clang/test/Profile/c-general.c
+++ b/clang/test/Profile/c-general.c
@@ -14,6 +14,7 @@
// RUN: %clang -fcs-profile-generate -E -dM %s | FileCheck -match-full-lines -check-prefix=PROFGENMACRO %s
//
// RUN: %clang -fprofile-use=%t.profdata -E -dM %s | FileCheck -match-full-lines -check-prefix=PROFUSEMACRO %s
+// RUN: %clang -fprofile-instr-use=%t.profdata -E -dM %s | FileCheck -match-full-lines -check-prefix=PROFUSEMACRO %s
// PROFGENMACRO:#define __LLVM_INSTR_PROFILE_GENERATE 1
// PROFUSEMACRO:#define __LLVM_INSTR_PROFILE_USE 1
diff --git a/compiler-rt/lib/profile/InstrProfiling.h b/compiler-rt/lib/profile/InstrProfiling.h
index 2210e048210637..01239083369187 100644
--- a/compiler-rt/lib/profile/InstrProfiling.h
+++ b/compiler-rt/lib/profile/InstrProfiling.h
@@ -14,16 +14,14 @@
// Make sure __LLVM_INSTR_PROFILE_GENERATE is always defined before
// including instr_prof_interface.h so the interface functions are
-// declared correctly for the runtime. Additionally, make sure
-// that __LLVM_INSTR_PROFILE_GENERATE is undefined only when it is
-// not explicitly defined somewhere else.
+// declared correctly for the runtime.
+// __LLVM_INSTR_PROFILE_GENERATE is always `#undef`ed after the header,
+// because compiler-rt does not support profiling the profiling runtime itself.
#ifndef __LLVM_INSTR_PROFILE_GENERATE
#define __LLVM_INSTR_PROFILE_GENERATE
+#endif
#include "profile/instr_prof_interface.h"
#undef __LLVM_INSTR_PROFILE_GENERATE
-#else
-#include "profile/instr_prof_interface.h"
-#endif
#define INSTR_PROF_VISIBILITY COMPILER_RT_VISIBILITY
#include "profile/InstrProfData.inc"
diff --git a/compiler-rt/test/profile/Linux/instrprof-weak-symbol.c b/compiler-rt/test/profile/Linux/instrprof-weak-symbol.c
index 88292974bdada3..4af69fecb34f63 100644
--- a/compiler-rt/test/profile/Linux/instrprof-weak-symbol.c
+++ b/compiler-rt/test/profile/Linux/instrprof-weak-symbol.c
@@ -5,13 +5,10 @@
__attribute__((weak)) void __llvm_profile_reset_counters(void);
-__attribute__((noinline)) int bar() { return 4; }
-int foo() {
+int main() {
if (__llvm_profile_reset_counters) {
__llvm_profile_reset_counters();
- return 0;
+ return 1;
}
- return bar();
+ return 0;
}
-
-int main() { return foo() - 4; }
More information about the cfe-commits
mailing list