v8: fix dragonflybsd build

src/platform-freebsd.cc

Index: src/platform-freebsd.cc
diff --git a/src/platform-freebsd.cc b/src/platform-freebsd.cc
index 3ec02b780c047ca157163384cb056c37c39d5c70..c2cf6cbaec814fae4686e4d04e0e0aaec57afb17 100644
--- a/src/platform-freebsd.cc
+++ b/src/platform-freebsd.cc
@@ -43,12 +43,15 @@
 #include <sys/fcntl.h>  // open
 #include <unistd.h>     // getpagesize
 // If you don't have execinfo.h then you need devel/libexecinfo from ports.
-#include <execinfo.h>   // backtrace, backtrace_symbols
 #include <strings.h>    // index
 #include <errno.h>
 #include <stdarg.h>
 #include <limits.h>
 
+#if !defined(__DragonFly__)

[Sven Panne, 2013/01/02 08:06:46]

One general comment about such #ifs: Instead of scattering obscure platform
#ifdefs all over the place, please use feature-based #ifdefs and #define the
corresponding preprocessor symbol at a single central place. In our concrete
example:

Use

   #ifdef HAVE_EXECINFO_H
   #include <execinfo.h>
   #endif

here and similar conditionals in the changes below. Make sure that
HAVE_EXECINFO_H is defined where it is available, e.g. via our GYP files.

Doing it this way has the advantage that the code is much, much easier to read
an maintain. I know that the current v8 code is guilty of doing this massively
wrong already, but we shouldn't make it worse... :-)

+#include <execinfo.h>   // backtrace, backtrace_symbols
+#endif
+
 #undef MAP_TYPE
 
 #include "v8.h"
@@ -296,6 +299,9 @@ void OS::SignalCodeMovingGC() {
 
 
 int OS::StackWalk(Vector<OS::StackFrame> frames) {
+#if defined(__DragonFly__)
+  return 0;
+#else
   int frames_size = frames.length();
   ScopedVector<void*> addresses(frames_size);
 
@@ -320,6 +326,7 @@ int OS::StackWalk(Vector<OS::StackFrame> frames) {
   free(symbols);
 
   return frames_count;
+#endif
 }
 
 
@@ -618,6 +625,13 @@ void FreeBSDSemaphore::Wait() {
 
 
 bool FreeBSDSemaphore::Wait(int timeout) {
+#if defined(__DragonFly__)
+  /* DragonFlyBSD lacks sem_timedwait() and there is no good way to emulate it.
+   */
+  if (sem_wait(&sem_)) abort();
+  USE(timeout);
+  return true;
+#else
   const long kOneSecondMicros = 1000000;  // NOLINT
 
   // Split timeout into second and nanosecond parts.
@@ -643,6 +657,7 @@ bool FreeBSDSemaphore::Wait(int timeout) {
     if (result == -1 && errno == ETIMEDOUT) return false;  // Timeout.
     CHECK(result == -1 && errno == EINTR);  // Signal caused spurious wakeup.
   }
+#endif
 }