2010-06-07 Doug Kwan <dougkwan@google.com>

	* arm.cc (Target_arm::do_relax): Reserve more space for stubs.
	Restrict stub-group size to be within long conditional branch
	range when working around cortex-A8 erratum.

diff --git a/gold/ChangeLog b/gold/ChangeLog
index 5442a9aed00e07f9d6f92d0d97d2840071622a85..938bb57a0523a2796e442147b3202220ea2b6e26 100644 (file)
--- a/gold/ChangeLog
+++ b/gold/ChangeLog
@@ -1,3 +1,9 @@
+2010-06-07  Doug Kwan  <dougkwan@google.com>
+
+       * arm.cc (Target_arm::do_relax): Reserve more space for stubs.
+       Restrict stub-group size to be within long conditional branch
+       range when working around cortex-A8 erratum.
+
 2010-06-07  Damien Diederen  <dd@crosstwine.com>
 
        * gold-threads.cc (Lock_impl_threads::Lock_impl_threads): Correct

diff --git a/gold/arm.cc b/gold/arm.cc
index 88102dcf9c60f31f14ef50843ac96c22b1d7e73a..f197eafda742af363bbaaf6fc1e1f76b1e0e4924 100644 (file)
--- a/gold/arm.cc
+++ b/gold/arm.cc
@@ -10844,12 +10844,6 @@ Target_arm<big_endian>::do_relax(
       bool stubs_always_after_branch = stub_group_size_param < 0;
       section_size_type stub_group_size = abs(stub_group_size_param);
 
-      // The Cortex-A8 erratum fix depends on stubs not being in the same 4K
-      // page as the first half of a 32-bit branch straddling two 4K pages.
-      // This is a crude way of enforcing that.
-      if (this->fix_cortex_a8_)
-       stubs_always_after_branch = true;
-
       if (stub_group_size == 1)
        {
          // Default value.
@@ -10859,14 +10853,24 @@ Target_arm<big_endian>::do_relax(
          // fixing cortex-a8 errata, the branch range has to be even smaller,
          // since wide conditional branch has a range of +-1MB only.
          //
-         // This value is 24K less than that, which allows for 2025
+         // This value is 48K less than that, which allows for 4096
          // 12-byte stubs.  If we exceed that, then we will fail to link.
          // The user will have to relink with an explicit group size
          // option.
-         if (this->fix_cortex_a8_)
-           stub_group_size = 1024276;
-         else
-           stub_group_size = 4170000;
+           stub_group_size = 4145152;
+       }
+
+      // The Cortex-A8 erratum fix depends on stubs not being in the same 4K
+      // page as the first half of a 32-bit branch straddling two 4K pages.
+      // This is a crude way of enforcing that.  In addition, long conditional
+      // branches of THUMB-2 have a range of +-1M.  If we are fixing cortex-A8
+      // erratum, limit the group size to  (1M - 12k) to avoid unreachable
+      // cortex-A8 stubs from long conditional branches.
+      if (this->fix_cortex_a8_)
+       {
+         stubs_always_after_branch = true;
+         const section_size_type cortex_a8_group_size = 1024 * (1024 - 12);
+         stub_group_size = std::max(stub_group_size, cortex_a8_group_size);
        }
 
       group_sections(layout, stub_group_size, stubs_always_after_branch);