[4.9] Refresh GCC 4.9 to the 20140514 snapshot.

For critical bug fixes including devirtualization and codegen.

Change-Id: I8138d3dc408fc12db5eecb01d2753d39219712f2

2 files changed, 35 insertions, 2 deletions

diff --git a/gcc-4.9/libbacktrace/ChangeLog b/gcc-4.9/libbacktrace/ChangeLog
index 5dfe80b38..8bcc677fd 100644
--- a/gcc-4.9/libbacktrace/ChangeLog
+++ b/gcc-4.9/libbacktrace/ChangeLog
@@ -1,3 +1,12 @@
+2014-05-08  Ian Lance Taylor  <iant@google.com>
+
+	Backport from mainline:
+	* mmap.c (backtrace_free): If freeing a large aligned block of
+	memory, call munmap rather than holding onto it.
+	(backtrace_vector_grow): When growing a vector, double the number
+	of pages requested.  When releasing the old version of a grown
+	vector, pass the correct size to backtrace_free.
+
 2014-04-22  Release Manager
 
 	* GCC 4.9.0 released.
diff --git a/gcc-4.9/libbacktrace/mmap.c b/gcc-4.9/libbacktrace/mmap.c
index b530e3823..5a9f6299b 100644
--- a/gcc-4.9/libbacktrace/mmap.c
+++ b/gcc-4.9/libbacktrace/mmap.c
@@ -164,6 +164,26 @@ backtrace_free (struct backtrace_state *state, void *addr, size_t size,
 {
   int locked;
 
+  /* If we are freeing a large aligned block, just release it back to
+     the system.  This case arises when growing a vector for a large
+     binary with lots of debug info.  Calling munmap here may cause us
+     to call mmap again if there is also a large shared library; we
+     just live with that.  */
+  if (size >= 16 * 4096)
+    {
+      size_t pagesize;
+
+      pagesize = getpagesize ();
+      if (((uintptr_t) addr & (pagesize - 1)) == 0
+	  && (size & (pagesize - 1)) == 0)
+	{
+	  /* If munmap fails for some reason, just add the block to
+	     the freelist.  */
+	  if (munmap (addr, size) == 0)
+	    return;
+	}
+    }
+
   /* If we can acquire the lock, add the new space to the free list.
      If we can't acquire the lock, just leak the memory.
      __sync_lock_test_and_set returns the old state of the lock, so we
@@ -209,14 +229,18 @@ backtrace_vector_grow (struct backtrace_state *state,size_t size,
 	    alc = pagesize;
 	}
       else
-	alc = (alc + pagesize - 1) & ~ (pagesize - 1);
+	{
+	  alc *= 2;
+	  alc = (alc + pagesize - 1) & ~ (pagesize - 1);
+	}
       base = backtrace_alloc (state, alc, error_callback, data);
       if (base == NULL)
 	return NULL;
       if (vec->base != NULL)
 	{
 	  memcpy (base, vec->base, vec->size);
-	  backtrace_free (state, vec->base, vec->alc, error_callback, data);
+	  backtrace_free (state, vec->base, vec->size + vec->alc,
+			  error_callback, data);
 	}
       vec->base = base;
       vec->alc = alc - vec->size;