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author | Mingyao Yang <mingyao@google.com> | 2015-03-07 06:37:59 -0800 |
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committer | Mingyao Yang <mingyao@google.com> | 2015-03-23 16:39:37 -0700 |
commit | e295e6ec5beaea31be5d7d3c996cd8cfa2053129 (patch) | |
tree | 4d8a657d23d511743ce35bee596544d7f652efdb /runtime/arch/x86_64 | |
parent | d24ba2c44c76a2b2dd13aafe8f7981c15be31a98 (diff) | |
download | art-e295e6ec5beaea31be5d7d3c996cd8cfa2053129.zip art-e295e6ec5beaea31be5d7d3c996cd8cfa2053129.tar.gz art-e295e6ec5beaea31be5d7d3c996cd8cfa2053129.tar.bz2 |
Deoptimization-based bce.
A mechanism is introduced that a runtime method can be called
from code compiled with optimizing compiler to deoptimize into
interpreter. This can be used to establish invariants in the managed code
If the invariant does not hold at runtime, we will deoptimize and continue
execution in the interpreter. This allows to optimize the managed code as
if the invariant was proven during compile time. However, the exception
will be thrown according to the semantics demanded by the spec.
The invariant and optimization included in this patch are based on the
length of an array. Given a set of array accesses with constant indices
{c1, ..., cn}, we can optimize away all bounds checks iff all 0 <= min(ci) and
max(ci) < array-length. The first can be proven statically. The second can be
established with a deoptimization-based invariant. This replaces n bounds
checks with one invariant check (plus slow-path code).
Change-Id: I8c6e34b56c85d25b91074832d13dba1db0a81569
Diffstat (limited to 'runtime/arch/x86_64')
-rw-r--r-- | runtime/arch/x86_64/entrypoints_init_x86_64.cc | 3 | ||||
-rw-r--r-- | runtime/arch/x86_64/quick_entrypoints_x86_64.S | 7 |
2 files changed, 8 insertions, 2 deletions
diff --git a/runtime/arch/x86_64/entrypoints_init_x86_64.cc b/runtime/arch/x86_64/entrypoints_init_x86_64.cc index b25d7a7..3bc0dc4 100644 --- a/runtime/arch/x86_64/entrypoints_init_x86_64.cc +++ b/runtime/arch/x86_64/entrypoints_init_x86_64.cc @@ -146,6 +146,9 @@ void InitEntryPoints(InterpreterEntryPoints* ipoints, JniEntryPoints* jpoints, qpoints->pThrowNoSuchMethod = art_quick_throw_no_such_method; qpoints->pThrowNullPointer = art_quick_throw_null_pointer_exception; qpoints->pThrowStackOverflow = art_quick_throw_stack_overflow; + + // Deoptimize + qpoints->pDeoptimize = art_quick_deoptimize_from_compiled_slow_path; #endif // __APPLE__ }; diff --git a/runtime/arch/x86_64/quick_entrypoints_x86_64.S b/runtime/arch/x86_64/quick_entrypoints_x86_64.S index 5edcd96..3a448a5 100644 --- a/runtime/arch/x86_64/quick_entrypoints_x86_64.S +++ b/runtime/arch/x86_64/quick_entrypoints_x86_64.S @@ -1600,7 +1600,11 @@ END_FUNCTION art_quick_instrumentation_exit * will long jump to the upcall with a special exception of -1. */ DEFINE_FUNCTION art_quick_deoptimize - pushq %rsi // Fake that we were called. Use hidden arg. + pushq %rsi // Entry point for a jump. Fake that we were called. + // Use hidden arg. +.globl SYMBOL(art_quick_deoptimize_from_compiled_slow_path) // Entry point for real calls + // from compiled slow paths. +SYMBOL(art_quick_deoptimize_from_compiled_slow_path): SETUP_SAVE_ALL_CALLEE_SAVE_FRAME // Stack should be aligned now. movq %gs:THREAD_SELF_OFFSET, %rdi // Pass Thread. @@ -1608,7 +1612,6 @@ DEFINE_FUNCTION art_quick_deoptimize int3 // Unreachable. END_FUNCTION art_quick_deoptimize - /* * String's compareTo. * |