ART: Target-dependent stack overflow, less check elision
Refactor the separate stack overflow reserved sizes from thread.h
into instruction_set.h and make sure they're used in the compiler.
Refactor the decision on when to elide stack overflow checks:
especially with large interpreter stack frames, it is not a good
idea to elide checks when the frame size is even close to the
reserved size. Currently enforce checks when the frame size is
>= 2KB, but make sure that frame sizes 1KB and below will elide
the checks (number from experience).
Bug: 15728765
Change-Id: I016bfd3d8218170cbccbd123ed5e2203db167c06
diff --git a/compiler/dex/quick/arm64/call_arm64.cc b/compiler/dex/quick/arm64/call_arm64.cc
index f1748ef..35263ea 100644
--- a/compiler/dex/quick/arm64/call_arm64.cc
+++ b/compiler/dex/quick/arm64/call_arm64.cc
@@ -337,13 +337,13 @@
* 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() &&
- (static_cast<size_t>(frame_size_) <
- Thread::kStackOverflowReservedBytes));
+ bool skip_overflow_check = mir_graph_->MethodIsLeaf() && !IsLargeFrame(frame_size_, kArm64);
NewLIR0(kPseudoMethodEntry);
- const bool large_frame = (static_cast<size_t>(frame_size_) > Thread::kStackOverflowReservedUsableBytes);
+ constexpr size_t kStackOverflowReservedUsableBytes = kArm64StackOverflowReservedBytes -
+ Thread::kStackOverflowSignalReservedBytes;
+ const bool large_frame = static_cast<size_t>(frame_size_) > kStackOverflowReservedUsableBytes;
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;
@@ -412,7 +412,7 @@
// Branch to throw target if there is not enough room.
OpRegRegImm(kOpSub, rs_x9, rs_rA64_SP, frame_size_without_spills);
LoadWordDisp(rs_rA64_SELF, Thread::StackEndOffset<8>().Int32Value(), rs_x8);
- LIR* branch = OpCmpBranch(kCondUlt, rs_rA64_SP, rs_x8, nullptr);
+ LIR* branch = OpCmpBranch(kCondUlt, rs_x9, rs_x8, nullptr);
AddSlowPath(new(arena_)StackOverflowSlowPath(this, branch, spill_size));
OpRegCopy(rs_rA64_SP, rs_x9); // Establish stack after checks.
} else {