[profile] Add interface to get profile filename

Summary:
Add __llvm_profile_get_filename interface to get the profile filename,
which can be used for identifying which profile file belongs to an app
when multiple binaries are instrumented and dumping profiles into the
same directory. The filename includes the path.

Reviewers: davidxl

Subscribers: delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D49529

llvm-svn: 337482

compiler-rt/lib/profile/InstrProfiling.h

@@ -170,6 +170,14 @@ void __llvm_profile_initialize_file(void);
  */
 const char *__llvm_profile_get_path_prefix();
 
+/*!
+ * \brief Return filename (including path) of the profile data. Note that if the
+ * user calls __llvm_profile_set_filename later after invoking this interface,
+ * the actual file name may differ from what is returned here.
+ * Side-effect: this API call will invoke malloc with dynamic memory allocation.
+ */
+const char *__llvm_profile_get_filename();
+
 /*! \brief Get the magic token for the file format. */
 uint64_t __llvm_profile_get_magic(void);
 

compiler-rt/lib/profile/InstrProfilingFile.c

@@ -69,6 +69,7 @@ typedef struct lprofFilename {
    * by runtime. */
   unsigned OwnsFilenamePat;
   const char *ProfilePathPrefix;
+  const char *Filename;
   char PidChars[MAX_PID_SIZE];
   char Hostname[COMPILER_RT_MAX_HOSTLEN];
   unsigned NumPids;
@@ -84,11 +85,11 @@ typedef struct lprofFilename {
   ProfileNameSpecifier PNS;
 } lprofFilename;
 
-COMPILER_RT_WEAK lprofFilename lprofCurFilename = {0, 0, 0, {0}, {0},
-                                                   0, 0, 0, PNS_unknown};
+COMPILER_RT_WEAK lprofFilename lprofCurFilename = {0,   0, 0, 0, {0},
+                                                   {0}, 0, 0, 0, PNS_unknown};
 
 static int getCurFilenameLength();
-static const char *getCurFilename(char *FilenameBuf);
+static const char *getCurFilename(char *FilenameBuf, int ForceUseBuf);
 static unsigned doMerging() { return lprofCurFilename.MergePoolSize; }
 
 /* Return 1 if there is an error, otherwise return  0.  */
@@ -266,7 +267,7 @@ static void truncateCurrentFile(void) {
 
   Length = getCurFilenameLength();
   FilenameBuf = (char *)COMPILER_RT_ALLOCA(Length + 1);
-  Filename = getCurFilename(FilenameBuf);
+  Filename = getCurFilename(FilenameBuf, 0);
   if (!Filename)
     return;
 
@@ -311,9 +312,12 @@ static int parseFilenamePattern(const char *FilenamePat,
   char *Hostname = &lprofCurFilename.Hostname[0];
   int MergingEnabled = 0;
 
-  /* Clean up cached prefix.  */
+  /* Clean up cached prefix and filename.  */
   if (lprofCurFilename.ProfilePathPrefix)
     free((void *)lprofCurFilename.ProfilePathPrefix);
+  if (lprofCurFilename.Filename)
+    free((void *)lprofCurFilename.Filename);
+
   memset(&lprofCurFilename, 0, sizeof(lprofCurFilename));
 
   if (lprofCurFilename.FilenamePat && lprofCurFilename.OwnsFilenamePat) {
@@ -428,17 +432,25 @@ static int getCurFilenameLength() {
 /* Return the pointer to the current profile file name (after substituting
  * PIDs and Hostnames in filename pattern. \p FilenameBuf is the buffer
  * to store the resulting filename. If no substitution is needed, the
- * current filename pattern string is directly returned. */
-static const char *getCurFilename(char *FilenameBuf) {
-  int I, J, PidLength, HostNameLength;
+ * current filename pattern string is directly returned, unless ForceUseBuf
+ * is enabled. */
+static const char *getCurFilename(char *FilenameBuf, int ForceUseBuf) {
+  int I, J, PidLength, HostNameLength, FilenamePatLength;
   const char *FilenamePat = lprofCurFilename.FilenamePat;
 
   if (!lprofCurFilename.FilenamePat || !lprofCurFilename.FilenamePat[0])
     return 0;
 
   if (!(lprofCurFilename.NumPids || lprofCurFilename.NumHosts ||
-        lprofCurFilename.MergePoolSize))
-    return lprofCurFilename.FilenamePat;
+        lprofCurFilename.MergePoolSize)) {
+    if (!ForceUseBuf)
+      return lprofCurFilename.FilenamePat;
+
+    FilenamePatLength = strlen(lprofCurFilename.FilenamePat);
+    memcpy(FilenameBuf, lprofCurFilename.FilenamePat, FilenamePatLength);
+    FilenameBuf[FilenamePatLength] = '\0';
+    return FilenameBuf;
+  }
 
   PidLength = strlen(lprofCurFilename.PidChars);
   HostNameLength = strlen(lprofCurFilename.Hostname);
@@ -492,7 +504,7 @@ const char *__llvm_profile_get_path_prefix(void) {
 
   Length = getCurFilenameLength();
   FilenameBuf = (char *)COMPILER_RT_ALLOCA(Length + 1);
-  Filename = getCurFilename(FilenameBuf);
+  Filename = getCurFilename(FilenameBuf, 0);
   if (!Filename)
     return "\0";
 
@@ -512,6 +524,29 @@ const char *__llvm_profile_get_path_prefix(void) {
   return Prefix;
 }
 
+COMPILER_RT_VISIBILITY
+const char *__llvm_profile_get_filename(void) {
+  int Length;
+  char *FilenameBuf;
+  const char *Filename;
+
+  if (lprofCurFilename.Filename)
+    return lprofCurFilename.Filename;
+
+  Length = getCurFilenameLength();
+  FilenameBuf = (char *)malloc(Length + 1);
+  if (!FilenameBuf) {
+    PROF_ERR("Failed to %s\n", "allocate memory.");
+    return "\0";
+  }
+  Filename = getCurFilename(FilenameBuf, 1);
+  if (!Filename)
+    return "\0";
+
+  lprofCurFilename.Filename = FilenameBuf;
+  return FilenameBuf;
+}
+
 /* This method is invoked by the runtime initialization hook
  * InstrProfilingRuntime.o if it is linked in. Both user specified
  * profile path via -fprofile-instr-generate= and LLVM_PROFILE_FILE
@@ -568,7 +603,7 @@ int __llvm_profile_write_file(void) {
 
   Length = getCurFilenameLength();
   FilenameBuf = (char *)COMPILER_RT_ALLOCA(Length + 1);
-  Filename = getCurFilename(FilenameBuf);
+  Filename = getCurFilename(FilenameBuf, 0);
 
   /* Check the filename. */
   if (!Filename) {

compiler-rt/test/profile/instrprof-get-filename.c

@@ -0,0 +1,39 @@
+// Test __llvm_profile_get_filename.
+// RUN: %clang_pgogen -O2 -o %t %s
+// RUN: %run %t
+
+#include <stdio.h>
+#include <string.h>
+
+const char *__llvm_profile_get_filename();
+void __llvm_profile_set_filename(const char *);
+
+int main(int argc, const char *argv[]) {
+  int i;
+  const char *filename;
+  const char *new_filename = "/path/to/test.profraw";
+
+  filename = __llvm_profile_get_filename();
+  if (strncmp(filename, "default_", 8)) {
+    fprintf(stderr,
+            "Error: got filename %s, expected it to start with 'default_'\n",
+            filename);
+    return 1;
+  }
+  if (strcmp(filename + strlen(filename) - strlen(".profraw"), ".profraw")) {
+    fprintf(stderr,
+            "Error: got filename %s, expected it to end with '.profraw'\n",
+            filename);
+    return 1;
+  }
+
+  __llvm_profile_set_filename(new_filename);
+  filename = __llvm_profile_get_filename();
+  if (strcmp(filename, new_filename)) {
+    fprintf(stderr, "Error: got filename %s, expected '%s'\n", filename,
+            new_filename);
+    return 1;
+  }
+
+  return 0;
+}