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/mir_to_lir.h b/compiler/dex/quick/mir_to_lir.h
index ca65432..f70087d 100644
--- a/compiler/dex/quick/mir_to_lir.h
+++ b/compiler/dex/quick/mir_to_lir.h
@@ -25,6 +25,7 @@
#include "dex/backend.h"
#include "dex/quick/resource_mask.h"
#include "driver/compiler_driver.h"
+#include "instruction_set.h"
#include "leb128.h"
#include "safe_map.h"
#include "utils/array_ref.h"
@@ -206,6 +207,36 @@
#define SLOW_TYPE_PATH (cu_->enable_debug & (1 << kDebugSlowTypePath))
#define EXERCISE_SLOWEST_STRING_PATH (cu_->enable_debug & (1 << kDebugSlowestStringPath))
+// Size of a frame that we definitely consider large. Anything larger than this should
+// definitely get a stack overflow check.
+static constexpr size_t kLargeFrameSize = 2 * KB;
+
+// Size of a frame that should be small. Anything leaf method smaller than this should run
+// without a stack overflow check.
+// The constant is from experience with frameworks code.
+static constexpr size_t kSmallFrameSize = 1 * KB;
+
+// Determine whether a frame is small or large, used in the decision on whether to elide a
+// stack overflow check on method entry.
+//
+// A frame is considered large when it's either above kLargeFrameSize, or a quarter of the
+// overflow-usable stack space.
+static constexpr bool IsLargeFrame(size_t size, InstructionSet isa) {
+ return size >= kLargeFrameSize || size >= GetStackOverflowReservedBytes(isa) / 4;
+}
+
+// We want to ensure that on all systems kSmallFrameSize will lead to false in IsLargeFrame.
+COMPILE_ASSERT(!IsLargeFrame(kSmallFrameSize, kArm),
+ kSmallFrameSize_is_not_a_small_frame_arm);
+COMPILE_ASSERT(!IsLargeFrame(kSmallFrameSize, kArm64),
+ kSmallFrameSize_is_not_a_small_frame_arm64);
+COMPILE_ASSERT(!IsLargeFrame(kSmallFrameSize, kMips),
+ kSmallFrameSize_is_not_a_small_frame_mips);
+COMPILE_ASSERT(!IsLargeFrame(kSmallFrameSize, kX86),
+ kSmallFrameSize_is_not_a_small_frame_x86);
+COMPILE_ASSERT(!IsLargeFrame(kSmallFrameSize, kX86_64),
+ kSmallFrameSize_is_not_a_small_frame_x64_64);
+
class Mir2Lir : public Backend {
public:
/*