[PGO] Exposing PGO's Counter Reset and File Dumping APIs

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());
 }

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;

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,

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

clang/lib/Frontend/InitPreprocessor.cpp

@@ -1364,12 +1364,22 @@ 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");
+
+  if (CodeGenOpts.hasProfileIRUse() || CodeGenOpts.hasProfileClangUse())
+    Builder.defineMacro("__LLVM_INSTR_PROFILE_USE");
+}
+
 /// 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 +1426,11 @@ void clang::InitializePreprocessor(
   InitializeStandardPredefinedMacros(PP.getTargetInfo(), PP.getLangOpts(),
                                      FEOpts, Builder);
 
+  // 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.
   Builder.append("# 1 \"<command line>\" 1");

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

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)
 

compiler-rt/include/profile/instr_prof_interface.h

@@ -0,0 +1,66 @@
+/*===---- 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.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+ *===-----------------------------------------------------------------------===
+ *
+ * This header provides a public interface for user programs to provide
+ * fine-grained control of counter reset and 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

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.

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;
+}