Experiment for updating the tcmalloc chromium branch to r144 (gperftools 2.0).

third_party/tcmalloc/chromium/src/symbolize.cc

Index: third_party/tcmalloc/chromium/src/symbolize.cc
diff --git a/third_party/tcmalloc/chromium/src/symbolize.cc b/third_party/tcmalloc/chromium/src/symbolize.cc
index ff45e3e78d16c1fe8ff4257ecf0864670453c582..d90c4b889ffe1df5e11d3ce7bb5029cc747a6eac 100644
--- a/third_party/tcmalloc/chromium/src/symbolize.cc
+++ b/third_party/tcmalloc/chromium/src/symbolize.cc
@@ -48,8 +48,16 @@
 #ifdef HAVE_POLL_H
 #include <poll.h>
 #endif
+#ifdef __MACH__
+#include <mach-o/dyld.h>   // for GetProgramInvocationName()
+#include <limits.h>        // for PATH_MAX
+#endif
+#if defined(__CYGWIN__) || defined(__CYGWIN32__)
+#include <io.h>            // for get_osfhandle()
+#endif
 #include <string>
 #include "base/commandlineflags.h"
+#include "base/logging.h"
 #include "base/sysinfo.h"
 
 using std::string;
@@ -65,6 +73,36 @@ DEFINE_string(symbolize_pprof,
 // a more-permanent copy that won't ever get destroyed.
 static string* g_pprof_path = new string(FLAGS_symbolize_pprof);
 
+// Returns NULL if we're on an OS where we can't get the invocation name.
+// Using a static var is ok because we're not called from a thread.
+static char* GetProgramInvocationName() {
+#if defined(HAVE_PROGRAM_INVOCATION_NAME)
+  extern char* program_invocation_name;  // gcc provides this
+  return program_invocation_name;
+#elif defined(__MACH__)
+  // We don't want to allocate memory for this since we may be
+  // calculating it when memory is corrupted.
+  static char program_invocation_name[PATH_MAX];
+  if (program_invocation_name[0] == '\0') {  // first time calculating
+    uint32_t length = sizeof(program_invocation_name);
+    if (_NSGetExecutablePath(program_invocation_name, &length))
+      return NULL;
+  }
+  return program_invocation_name;
+#else
+  return NULL;   // figure out a way to get argv[0]
+#endif
+}
+
+// Prints an error message when you can't run Symbolize().
+static void PrintError(const char* reason) {
+  RAW_LOG(ERROR,
+          "*** WARNING: Cannot convert addresses to symbols in output below.\n"
+          "*** Reason: %s\n"
+          "*** If you cannot fix this, try running pprof directly.\n",
+          reason);
+}
+
 void SymbolTable::Add(const void* addr) {
   symbolization_table_[addr] = "";
 }
@@ -79,14 +117,24 @@ const char* SymbolTable::GetSymbol(const void* addr) {
 // Note that the forking/etc is not thread-safe or re-entrant.  That's
 // ok for the purpose we need -- reporting leaks detected by heap-checker
 // -- but be careful if you decide to use this routine for other purposes.
+// Returns number of symbols read on error.  If can't symbolize, returns 0
+// and emits an error message about why.
 int SymbolTable::Symbolize() {
 #if !defined(HAVE_UNISTD_H)  || !defined(HAVE_SYS_SOCKET_H) || !defined(HAVE_SYS_WAIT_H)
+  PrintError("Perftools does not know how to call a sub-process on this O/S");
   return 0;
-#elif !defined(HAVE_PROGRAM_INVOCATION_NAME)
-  return 0;   // TODO(csilvers): get argv[0] somehow
 #else
+  const char* argv0 = GetProgramInvocationName();
+  if (argv0 == NULL) {  // can't call symbolize if we can't figure out our name
+    PrintError("Cannot figure out the name of this executable (argv0)");
+    return 0;
+  }
+  if (access(g_pprof_path->c_str(), R_OK) != 0) {
+    PrintError("Cannot find 'pprof' (is PPROF_PATH set correctly?)");
+    return 0;
+  }
+
   // All this work is to do two-way communication.  ugh.
-  extern char* program_invocation_name;  // gcc provides this
   int *child_in = NULL;   // file descriptors
   int *child_out = NULL;  // for now, we don't worry about child_err
   int child_fds[5][2];    // socketpair may be called up to five times below
@@ -102,6 +150,7 @@ int SymbolTable::Symbolize() {
       for (int j = 0; j < i; j++) {
         close(child_fds[j][0]);
         close(child_fds[j][1]);
+        PrintError("Cannot create a socket pair");
         return 0;
       }
     } else {
@@ -127,6 +176,7 @@ int SymbolTable::Symbolize() {
       close(child_in[1]);
       close(child_out[0]);
       close(child_out[1]);
+      PrintError("Unknown error calling fork()");
       return 0;
     }
     case 0: {  // child
@@ -142,13 +192,15 @@ int SymbolTable::Symbolize() {
       unsetenv("HEAPCHECK");
       unsetenv("PERFTOOLS_VERBOSE");
       execlp(g_pprof_path->c_str(), g_pprof_path->c_str(),
-             "--symbols", program_invocation_name, NULL);
+             "--symbols", argv0, NULL);
       _exit(3);  // if execvp fails, it's bad news for us
     }
     default: {  // parent
       close(child_in[0]);   // child uses the 0's, parent uses the 1's
       close(child_out[0]);  // child uses the 0's, parent uses the 1's
 #ifdef HAVE_POLL_H
+      // Waiting for 1ms seems to give the OS time to notice any errors.
+      poll(0, 0, 1);
       // For maximum safety, we check to make sure the execlp
       // succeeded before trying to write.  (Otherwise we'll get a
       // SIGPIPE.)  For systems without poll.h, we'll just skip this
@@ -156,10 +208,17 @@ int SymbolTable::Symbolize() {
       struct pollfd pfd = { child_in[1], POLLOUT, 0 };
       if (!poll(&pfd, 1, 0) || !(pfd.revents & POLLOUT) ||
           (pfd.revents & (POLLHUP|POLLERR))) {
+        PrintError("Cannot run 'pprof' (is PPROF_PATH set correctly?)");
         return 0;
       }
 #endif
+#if defined(__CYGWIN__) || defined(__CYGWIN32__)
+      // On cygwin, DumpProcSelfMaps() takes a HANDLE, not an fd.  Convert.
+      const HANDLE symbols_handle = (HANDLE) get_osfhandle(child_in[1]);
+      DumpProcSelfMaps(symbols_handle);
+#else
       DumpProcSelfMaps(child_in[1]);  // what pprof expects on stdin
+#endif
 
       // Allocate 24 bytes = ("0x" + 8 bytes + "\n" + overhead) for each
       // address to feed to pprof.
@@ -185,6 +244,7 @@ int SymbolTable::Symbolize() {
                               kSymbolBufferSize - total_bytes_read);
         if (bytes_read < 0) {
           close(child_out[1]);
+          PrintError("Cannot read data from pprof");
           return 0;
         } else if (bytes_read == 0) {
           close(child_out[1]);
@@ -214,6 +274,7 @@ int SymbolTable::Symbolize() {
       return num_symbols;
     }
   }
+  PrintError("Unkown error (should never occur!)");
   return 0;  // shouldn't be reachable
 #endif
 }