InstrProf: Fix shared object profiling

Change the API of the instrumented profiling library to work with shared
objects.

  - Most things are now declared hidden, so that each executable gets
    its own copy.

  - Initialization hooks up a linked list of writers.

  - The raw format with shared objects that are profiled consists of a
    concatenated series of profiles.  llvm-profdata knows how to deal
    with that since r208938.

<rdar://problem/16918688>

llvm-svn: 208940

compiler-rt/lib/profile/InstrProfiling.c

@@ -10,6 +10,7 @@
 #include "InstrProfiling.h"
 #include <string.h>
 
+__attribute__((visibility("hidden")))
 uint64_t __llvm_profile_get_magic(void) {
   /* Magic number to detect file format and endianness.
    *
@@ -32,11 +33,13 @@ uint64_t __llvm_profile_get_magic(void) {
     (uint64_t)129;
 }
 
+__attribute__((visibility("hidden")))
 uint64_t __llvm_profile_get_version(void) {
   /* This should be bumped any time the output format changes. */
   return 1;
 }
 
+__attribute__((visibility("hidden")))
 void __llvm_profile_reset_counters(void) {
   uint64_t *I = __llvm_profile_counters_begin();
   uint64_t *E = __llvm_profile_counters_end();

compiler-rt/lib/profile/InstrProfiling.h

@@ -83,6 +83,9 @@ void __llvm_profile_set_filename(const char *Name);
 /*! \brief Register to write instrumentation data to file at exit. */
 int __llvm_profile_register_write_file_atexit(void);
 
+/*! \brief Register the write file function for this executable. */
+void __llvm_profile_register_write_file(void);
+
 /*! \brief Get the magic token for the file format. */
 uint64_t __llvm_profile_get_magic(void);
 

compiler-rt/lib/profile/InstrProfilingBuffer.c

@@ -10,14 +10,18 @@
 #include "InstrProfiling.h"
 #include <string.h>
 
+__attribute__((visibility("hidden")))
 uint64_t __llvm_profile_get_size_for_buffer(void) {
   /* Match logic in __llvm_profile_write_buffer(). */
+  const uint64_t NamesSize = PROFILE_RANGE_SIZE(names) * sizeof(char);
+  const uint64_t Padding = sizeof(uint64_t) - NamesSize % sizeof(uint64_t);
   return sizeof(uint64_t) * PROFILE_HEADER_SIZE +
      PROFILE_RANGE_SIZE(data) * sizeof(__llvm_profile_data) +
      PROFILE_RANGE_SIZE(counters) * sizeof(uint64_t) +
-     PROFILE_RANGE_SIZE(names) * sizeof(char);
+     NamesSize + Padding;
 }
 
+__attribute__((visibility("hidden")))
 int __llvm_profile_write_buffer(char *Buffer) {
   /* Match logic in __llvm_profile_get_size_for_buffer().
    * Match logic in __llvm_profile_write_file().
@@ -33,6 +37,10 @@ int __llvm_profile_write_buffer(char *Buffer) {
   const uint64_t DataSize = DataEnd - DataBegin;
   const uint64_t CountersSize = CountersEnd - CountersBegin;
   const uint64_t NamesSize = NamesEnd - NamesBegin;
+  const uint64_t Padding = sizeof(uint64_t) - NamesSize % sizeof(uint64_t);
+
+  /* Enough zeroes for padding. */
+  const char Zeroes[sizeof(uint64_t)] = {0};
 
   /* Create the header. */
   uint64_t Header[PROFILE_HEADER_SIZE];
@@ -54,6 +62,7 @@ int __llvm_profile_write_buffer(char *Buffer) {
   UPDATE_memcpy(DataBegin,     DataSize      * sizeof(__llvm_profile_data));
   UPDATE_memcpy(CountersBegin, CountersSize  * sizeof(uint64_t));
   UPDATE_memcpy(NamesBegin,    NamesSize     * sizeof(char));
+  UPDATE_memcpy(Zeroes,        Padding       * sizeof(char));
 #undef UPDATE_memcpy
 
   return 0;

compiler-rt/lib/profile/InstrProfilingFile.c

@@ -25,6 +25,10 @@ static int writeFile(FILE *File) {
   const uint64_t DataSize = DataEnd - DataBegin;
   const uint64_t CountersSize = CountersEnd - CountersBegin;
   const uint64_t NamesSize = NamesEnd - NamesBegin;
+  const uint64_t Padding = sizeof(uint64_t) - NamesSize % sizeof(uint64_t);
+
+  /* Enough zeroes for padding. */
+  const char Zeroes[sizeof(uint64_t)] = {0};
 
   /* Create the header. */
   uint64_t Header[PROFILE_HEADER_SIZE];
@@ -43,9 +47,30 @@ static int writeFile(FILE *File) {
   CHECK_fwrite(DataBegin,     sizeof(__llvm_profile_data), DataSize, File);
   CHECK_fwrite(CountersBegin, sizeof(uint64_t), CountersSize, File);
   CHECK_fwrite(NamesBegin,    sizeof(char), NamesSize, File);
+  CHECK_fwrite(Zeroes,        sizeof(char), Padding, File);
 #undef CHECK_fwrite
 
-   return 0;
+  return 0;
+}
+
+typedef struct __llvm_profile_writer {
+  struct __llvm_profile_writer *Next;
+  int (*Data)(FILE *);
+} __llvm_profile_writer;
+
+__attribute__((weak)) __llvm_profile_writer *__llvm_profile_HeadWriter = NULL;
+static __llvm_profile_writer Writer = {NULL, writeFile};
+
+__attribute__((visibility("hidden")))
+void __llvm_profile_register_write_file(void) {
+  static int HasBeenRegistered = 0;
+
+  if (HasBeenRegistered)
+    return;
+
+  HasBeenRegistered = 1;
+  Writer.Next = __llvm_profile_HeadWriter;
+  __llvm_profile_HeadWriter = &Writer;
 }
 
 static int writeFileWithName(const char *OutputName) {
@@ -57,19 +82,28 @@ static int writeFileWithName(const char *OutputName) {
   if (!OutputFile)
     return -1;
 
-  RetVal = writeFile(OutputFile);
+  __llvm_profile_writer *Writer = __llvm_profile_HeadWriter;
+  if (Writer)
+    for (; Writer; Writer = Writer->Next) {
+      RetVal = Writer->Data(OutputFile);
+      if (RetVal != 0)
+        break;
+    }
+  else
+    // Default to calling this executable's writeFile.
+    RetVal = writeFile(OutputFile);
 
   fclose(OutputFile);
   return RetVal;
 }
 
-static const char *CurrentFilename = NULL;
-void __llvm_profile_set_filename(const char *Filename) {
-  CurrentFilename = Filename;
+__attribute__((weak)) const char *__llvm_profile_CurrentFilename = NULL;
+__attribute__((weak)) void __llvm_profile_set_filename(const char *Filename) {
+  __llvm_profile_CurrentFilename = Filename;
 }
 
 int getpid(void);
-int __llvm_profile_write_file(void) {
+__attribute__((weak)) int __llvm_profile_write_file(void) {
   char *AllocatedFilename = NULL;
   int I, J;
   int RetVal;
@@ -80,7 +114,7 @@ int __llvm_profile_write_file(void) {
   int NumPids = 0;
 
   /* Get the filename. */
-  const char *Filename = CurrentFilename;
+  const char *Filename = __llvm_profile_CurrentFilename;
 #define UPDATE_FILENAME(NextFilename) \
   if (!Filename || !Filename[0]) Filename = NextFilename
   UPDATE_FILENAME(getenv("LLVM_PROFILE_FILE"));
@@ -131,7 +165,7 @@ static void writeFileWithoutReturn(void) {
   __llvm_profile_write_file();
 }
 
-int __llvm_profile_register_write_file_atexit(void) {
+__attribute__((weak)) int __llvm_profile_register_write_file_atexit(void) {
   static int HasBeenRegistered = 0;
 
   if (HasBeenRegistered)

compiler-rt/lib/profile/InstrProfilingPlatformDarwin.c

@@ -11,21 +11,33 @@
 
 #if defined(__APPLE__)
 /* Use linker magic to find the bounds of the Data section. */
+__attribute__((visibility("hidden")))
 extern __llvm_profile_data DataStart __asm("section$start$__DATA$__llvm_prf_data");
+__attribute__((visibility("hidden")))
 extern __llvm_profile_data DataEnd   __asm("section$end$__DATA$__llvm_prf_data");
+__attribute__((visibility("hidden")))
 extern char NamesStart __asm("section$start$__DATA$__llvm_prf_names");
+__attribute__((visibility("hidden")))
 extern char NamesEnd   __asm("section$end$__DATA$__llvm_prf_names");
+__attribute__((visibility("hidden")))
 extern uint64_t CountersStart __asm("section$start$__DATA$__llvm_prf_cnts");
+__attribute__((visibility("hidden")))
 extern uint64_t CountersEnd   __asm("section$end$__DATA$__llvm_prf_cnts");
 
+__attribute__((visibility("hidden")))
 const __llvm_profile_data *__llvm_profile_data_begin(void) {
   return &DataStart;
 }
+__attribute__((visibility("hidden")))
 const __llvm_profile_data *__llvm_profile_data_end(void) {
   return &DataEnd;
 }
+__attribute__((visibility("hidden")))
 const char *__llvm_profile_names_begin(void) { return &NamesStart; }
+__attribute__((visibility("hidden")))
 const char *__llvm_profile_names_end(void) { return &NamesEnd; }
+__attribute__((visibility("hidden")))
 uint64_t *__llvm_profile_counters_begin(void) { return &CountersStart; }
+__attribute__((visibility("hidden")))
 uint64_t *__llvm_profile_counters_end(void) { return &CountersEnd; }
 #endif

compiler-rt/lib/profile/InstrProfilingPlatformOther.c

@@ -26,6 +26,7 @@ static uint64_t *CountersLast = NULL;
  * calls are only required (and only emitted) on targets where we haven't
  * implemented linker magic to find the bounds of the sections.
  */
+__attribute__((visibility("hidden")))
 void __llvm_profile_register_function(void *Data_) {
   /* TODO: Only emit this function if we can't use linker magic. */
   const __llvm_profile_data *Data = (__llvm_profile_data*)Data_;
@@ -54,14 +55,20 @@ void __llvm_profile_register_function(void *Data_) {
 #undef UPDATE_LAST
 }
 
+__attribute__((visibility("hidden")))
 const __llvm_profile_data *__llvm_profile_data_begin(void) {
   return DataFirst;
 }
+__attribute__((visibility("hidden")))
 const __llvm_profile_data *__llvm_profile_data_end(void) {
   return DataLast;
 }
+__attribute__((visibility("hidden")))
 const char *__llvm_profile_names_begin(void) { return NamesFirst; }
+__attribute__((visibility("hidden")))
 const char *__llvm_profile_names_end(void) { return NamesLast; }
+__attribute__((visibility("hidden")))
 uint64_t *__llvm_profile_counters_begin(void) { return CountersFirst; }
+__attribute__((visibility("hidden")))
 uint64_t *__llvm_profile_counters_end(void) { return CountersLast; }
 #endif

compiler-rt/lib/profile/InstrProfilingRuntime.cc

@@ -11,17 +11,20 @@ extern "C" {
 
 #include "InstrProfiling.h"
 
-int __llvm_profile_runtime;
+__attribute__((visibility("hidden"))) int __llvm_profile_runtime;
 
 }
 
 namespace {
 
-class RegisterAtExit {
+class RegisterRuntime {
 public:
-  RegisterAtExit() { __llvm_profile_register_write_file_atexit(); }
+  RegisterRuntime() {
+    __llvm_profile_register_write_file_atexit();
+    __llvm_profile_register_write_file();
+  }
 };
 
-RegisterAtExit Registration;
+RegisterRuntime Registration;
 
 }

compiler-rt/test/profile/Inputs/instrprof-dynamic-a.cpp

@@ -0,0 +1,7 @@
+#include "instrprof-dynamic-header.h"
+void a() {
+  if (true) {
+    bar<void>();
+    bar<char>();
+  }
+}

compiler-rt/test/profile/Inputs/instrprof-dynamic-b.cpp

@@ -0,0 +1,7 @@
+#include "instrprof-dynamic-header.h"
+void b() {
+  if (true) {
+    bar<void>();
+    bar<int>();
+  }
+}

compiler-rt/test/profile/Inputs/instrprof-dynamic-header.h

@@ -0,0 +1,5 @@
+template <class T> void bar() {
+  if (true) {}
+}
+void a();
+void b();

compiler-rt/test/profile/Inputs/instrprof-dynamic-main.cpp

@@ -0,0 +1,9 @@
+#include "instrprof-dynamic-header.h"
+void foo(int K) { if (K) {} }
+int main(int argc, char *argv[]) {
+  foo(5);
+  bar<void>();
+  a();
+  b();
+  return 0;
+}

compiler-rt/test/profile/instrprof-dynamic-one-shared.test

@@ -0,0 +1,23 @@
+RUN: mkdir -p %t.d
+RUN: %clang_profgen -o %t.d/a.shared -fPIC -shared %S/Inputs/instrprof-dynamic-a.cpp
+RUN: %clang_profgen -o %t-shared -fPIC -rpath %t.d %t.d/a.shared %S/Inputs/instrprof-dynamic-b.cpp %S/Inputs/instrprof-dynamic-main.cpp
+
+RUN: %clang_profgen -o %t-static %S/Inputs/instrprof-dynamic-a.cpp %S/Inputs/instrprof-dynamic-b.cpp %S/Inputs/instrprof-dynamic-main.cpp
+
+RUN: env LLVM_PROFILE_FILE=%t-static.profraw %run %t-static
+RUN: env LLVM_PROFILE_FILE=%t-shared.profraw %run %t-shared
+
+RUN: llvm-profdata merge -o %t-static.profdata %t-static.profraw
+RUN: llvm-profdata merge -o %t-shared.profdata %t-shared.profraw
+
+RUN: %clang_profuse=%t-static.profdata -o %t-a.static.ll -S -emit-llvm %S/Inputs/instrprof-dynamic-a.cpp
+RUN: %clang_profuse=%t-shared.profdata -o %t-a.shared.ll -S -emit-llvm %S/Inputs/instrprof-dynamic-a.cpp
+RUN: diff %t-a.static.ll %t-a.shared.ll
+
+RUN: %clang_profuse=%t-static.profdata -o %t-b.static.ll -S -emit-llvm %S/Inputs/instrprof-dynamic-b.cpp
+RUN: %clang_profuse=%t-shared.profdata -o %t-b.shared.ll -S -emit-llvm %S/Inputs/instrprof-dynamic-b.cpp
+RUN: diff %t-b.static.ll %t-b.shared.ll
+
+RUN: %clang_profuse=%t-static.profdata -o %t-main.static.ll -S -emit-llvm %S/Inputs/instrprof-dynamic-main.cpp
+RUN: %clang_profuse=%t-shared.profdata -o %t-main.shared.ll -S -emit-llvm %S/Inputs/instrprof-dynamic-main.cpp
+RUN: diff %t-main.static.ll %t-main.shared.ll

compiler-rt/test/profile/instrprof-dynamic-two-shared.test

@@ -0,0 +1,24 @@
+RUN: mkdir -p %t.d
+RUN: %clang_profgen -o %t.d/a.shared -fPIC -shared %S/Inputs/instrprof-dynamic-a.cpp
+RUN: %clang_profgen -o %t.d/b.shared -fPIC -shared %S/Inputs/instrprof-dynamic-b.cpp
+RUN: %clang_profgen -o %t-shared -fPIC -rpath %t.d %t.d/a.shared %t.d/b.shared %S/Inputs/instrprof-dynamic-main.cpp
+
+RUN: %clang_profgen -o %t-static %S/Inputs/instrprof-dynamic-a.cpp %S/Inputs/instrprof-dynamic-b.cpp %S/Inputs/instrprof-dynamic-main.cpp
+
+RUN: env LLVM_PROFILE_FILE=%t-static.profraw %run %t-static
+RUN: env LLVM_PROFILE_FILE=%t-shared.profraw %run %t-shared
+
+RUN: llvm-profdata merge -o %t-static.profdata %t-static.profraw
+RUN: llvm-profdata merge -o %t-shared.profdata %t-shared.profraw
+
+RUN: %clang_profuse=%t-static.profdata -o %t-a.static.ll -S -emit-llvm %S/Inputs/instrprof-dynamic-a.cpp
+RUN: %clang_profuse=%t-shared.profdata -o %t-a.shared.ll -S -emit-llvm %S/Inputs/instrprof-dynamic-a.cpp
+RUN: diff %t-a.static.ll %t-a.shared.ll
+
+RUN: %clang_profuse=%t-static.profdata -o %t-b.static.ll -S -emit-llvm %S/Inputs/instrprof-dynamic-b.cpp
+RUN: %clang_profuse=%t-shared.profdata -o %t-b.shared.ll -S -emit-llvm %S/Inputs/instrprof-dynamic-b.cpp
+RUN: diff %t-b.static.ll %t-b.shared.ll
+
+RUN: %clang_profuse=%t-static.profdata -o %t-main.static.ll -S -emit-llvm %S/Inputs/instrprof-dynamic-main.cpp
+RUN: %clang_profuse=%t-shared.profdata -o %t-main.shared.ll -S -emit-llvm %S/Inputs/instrprof-dynamic-main.cpp
+RUN: diff %t-main.static.ll %t-main.shared.ll

compiler-rt/test/profile/lit.cfg

@@ -27,6 +27,9 @@ if config.test_exec_root is None:
 # Test suffixes.
 config.suffixes = ['.c', '.cc', '.cpp', '.m', '.mm', '.ll', '.test']
 
+# What to exclude.
+config.excludes = ['Inputs']
+
 # Clang flags.
 clang_cflags = [config.target_cflags]