MFC r260311, r260831:

gcc: Add support for Apple's Block extension

Block objects [1] are a C-level syntactic and runtime feature. They
are similar to standard C functions, but in addition to executable
code they may also contain variable bindings to automatic (stack)
or managed (heap) memory. A block can therefore maintain a set of
state (data) that it can use to impact behavior when executed.

This port is based on Apple's GCC 5646 with some bugfixes from
Apple GCC 5666.3. It has some small differences with the support
in clang, which remains the recommended compiler.

Perhaps the most notable difference is that in GCC __block is not
actually a keyword, but a macro. There may be workaround for this
issue in the future. Other issues can be consulted in the clang
documentation [2]

For better compatiblity with Apple's GCC and llvm-gcc, some related
fixes and features from Apple have been included. Support for the
non-standard nested functions in GCC is now off by default.

No effort was made to update the ObjC support since FreeBSD doesn't
carry ObjC in the base system but some of the code crept in and
was more difficult to remove than to adjust.

References:
[1]
https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/Blocks/Articles/00_Introduction.html
[2]
http://clang.llvm.org/compatibility.html#block-variable-initialization

Obtained from:	Apple GCC 4.2

1 files changed, 17 insertions, 5 deletions

diff --git a/contrib/gcc/ggc-common.c b/contrib/gcc/ggc-common.c
index fe75320..0c9a33f 100644
--- a/contrib/gcc/ggc-common.c
+++ b/contrib/gcc/ggc-common.c
@@ -716,10 +716,12 @@ ggc_min_expand_heuristic (void)
   min_expand = ggc_rlimit_bound (min_expand);
 
   /* The heuristic is a percentage equal to 30% + 70%*(RAM/1GB), yielding
-     a lower bound of 30% and an upper bound of 100% (when RAM >= 1GB).  */
+  APPLE LOCAL retune gc params 6124839
+     a lower bound of 30% and an upper bound of 150% (when RAM >= 1.7GB).  */
   min_expand /= 1024*1024*1024;
   min_expand *= 70;
-  min_expand = MIN (min_expand, 70);
+  /* APPLE LOCAL retune gc params 6124839 */
+  min_expand = MIN (min_expand, 120);
   min_expand += 30;
 
   return min_expand;
@@ -727,7 +729,8 @@ ggc_min_expand_heuristic (void)
 
 /* Heuristic to set a default for GGC_MIN_HEAPSIZE.  */
 int
-ggc_min_heapsize_heuristic (void)
+/* APPLE LOCAL retune gc params 6124839 */
+ggc_min_heapsize_heuristic (bool optimize)
 {
   double phys_kbytes = physmem_total();
   double limit_kbytes = ggc_rlimit_bound (phys_kbytes * 2);
@@ -739,6 +742,13 @@ ggc_min_heapsize_heuristic (void)
      bound of 128M (when RAM >= 1GB).  */
   phys_kbytes /= 8;
 
+  /* APPLE LOCAL begin retune gc params 6124839 */
+
+  /* Additionally, on a multicore machine, we assume that we share the
+     memory with others reasonably equally.  */
+  phys_kbytes /= (double)ncpu_available() / (2 - optimize);
+  /* APPLE LOCAL end retune gc params 6124839 */
+
 #if defined(HAVE_GETRLIMIT) && defined (RLIMIT_RSS)
   /* Try not to overrun the RSS limit while doing garbage collection.  
      The RSS limit is only advisory, so no margin is subtracted.  */
@@ -765,11 +775,13 @@ ggc_min_heapsize_heuristic (void)
 }
 
 void
-init_ggc_heuristics (void)
+/* APPLE LOCAL retune gc params 6124839 */
+init_ggc_heuristics (bool optimize ATTRIBUTE_UNUSED)
 {
 #if !defined ENABLE_GC_CHECKING && !defined ENABLE_GC_ALWAYS_COLLECT
   set_param_value ("ggc-min-expand", ggc_min_expand_heuristic());
-  set_param_value ("ggc-min-heapsize", ggc_min_heapsize_heuristic());
+  /* APPLE LOCAL retune gc params 6124839 */
+  set_param_value ("ggc-min-heapsize", ggc_min_heapsize_heuristic(optimize));
 #endif
 }