commit 648d7112609dd19c38131b3e71c37bcbbd19d11e
author Dave Allison <dallison@google.com> Fri Jul 25 16:15:27 2014 -0700
committer Dave Allison <dallison@google.com> Wed Aug 13 09:01:41 2014 -0700
tree 54062831327c660acb309e877e8d8df9ba0c2d5d
parent 99c251bbd225dd97d0deece29559a430b12a0b66

Reduce stack usage for overflow checks

This reduces the stack space reserved for overflow checks to 12K, split
into an 8K gap and a 4K protected region.  GC needs over 8K when running
in a stack overflow situation.

Also prevents signal runaway by detecting a signal inside code that
resulted from a signal handler invokation.  And adds a max signal count to
the SignalTest to prevent it running forever.

Also reduces the number of iterations for the InterfaceTest as this was
taking (almost) forever with the --trace option on run-test.

Bug: 15435566

Change-Id: Id4fd46f22d52d42a9eb431ca07948673e8fda694

compiler/dex/quick/arm64/call_arm64.cc

diff --git a/compiler/dex/quick/arm64/call_arm64.cc b/compiler/dex/quick/arm64/call_arm64.cc
index 28b747b..0538c31 100644
--- a/compiler/dex/quick/arm64/call_arm64.cc
+++ b/compiler/dex/quick/arm64/call_arm64.cc
@@ -329,16 +329,20 @@
    * We can safely skip the stack overflow check if we're
    * a leaf *and* our frame size < fudge factor.
    */
-  bool skip_overflow_check = mir_graph_->MethodIsLeaf() && !IsLargeFrame(frame_size_, kArm64);
+  bool skip_overflow_check = mir_graph_->MethodIsLeaf() && !FrameNeedsStackCheck(frame_size_, kArm64);
 
   NewLIR0(kPseudoMethodEntry);
 
+  const size_t kStackOverflowReservedUsableBytes = GetStackOverflowReservedBytes(kArm64);
+  const bool large_frame = static_cast<size_t>(frame_size_) > kStackOverflowReservedUsableBytes;
+  bool generate_explicit_stack_overflow_check = large_frame ||
+    !cu_->compiler_driver->GetCompilerOptions().GetImplicitStackOverflowChecks();
   const int spill_count = num_core_spills_ + num_fp_spills_;
   const int spill_size = (spill_count * kArm64PointerSize + 15) & ~0xf;  // SP 16 byte alignment.
   const int frame_size_without_spills = frame_size_ - spill_size;
 
   if (!skip_overflow_check) {
-    if (!cu_->compiler_driver->GetCompilerOptions().GetImplicitStackOverflowChecks()) {
+    if (generate_explicit_stack_overflow_check) {
       // Load stack limit
       LoadWordDisp(rs_xSELF, Thread::StackEndOffset<8>().Int32Value(), rs_xIP1);
     } else {
@@ -365,7 +369,7 @@
   }
 
   if (!skip_overflow_check) {
-    if (!cu_->compiler_driver->GetCompilerOptions().GetImplicitStackOverflowChecks()) {
+    if (generate_explicit_stack_overflow_check) {
       class StackOverflowSlowPath: public LIRSlowPath {
       public:
         StackOverflowSlowPath(Mir2Lir* m2l, LIR* branch, size_t sp_displace) :