Changeset 277576 in webkit for trunk/Source/JavaScriptCore/jit/JIT.cpp

Timestamp:

May 16, 2021, 9:20:52 PM (4 years ago)

Author:

[email protected]

Message:

Implement baseline op_enter, op_ret, op_check_traps, op_throw using JIT thunks.
​https://bugs.webkit.org/show_bug.cgi?id=225846

Reviewed by Filip Pizlo.

op_enter, op_ret, op_check_traps are 3 of the most common opcodes. Throwing in
op_throw because it's easy.

In this patch, the following changes were also made:

1. Renamed copyCalleeSavesFromFrameOrRegisterToEntryFrameCalleeSavesBuffer() to copyLLIntBaselineCalleeSavesFromFrameOrRegisterToEntryFrameCalleeSavesBuffer().

It is only used by the baseline JIT. Changed it to always operate on
RegisterAtOffsetList::llintBaselineCalleeSaveRegisters(). This removes the
dependency on a current codeBlock being compiled, and allows us to use it
for a JIT thunk.

2. Added JIT::emitNakedNearJump() to make it easy to emit direct jumps to JIT thunks.

Currently, it is only used by op_ret and op_throw.

3. Changed some thunks to use emitNonPatchableExceptionCheck() instead emitExceptionCheck() to make it explicit that these are not intended to be patchable.

With this patch, --dumpLinkBufferStats shows the following changes in emitted
JIT code size (using a single run of the CLI version of JetStream2 on AS Mac)
comparing to current tip of tree:

Base New Diff

BaselineJIT: 77429400 (73.842430 MB) 72407904 (69.053558 MB) 0.94x (reduction)

DFG: 36160880 (34.485703 MB) 36622176 (34.925629 MB) 1.01x

Thunk: 23159024 (22.086166 MB) 23295448 (22.216270 MB) 1.01x

InlineCache: 22068348 (21.046017 MB) 22157236 (21.130787 MB) 1.00x

FTL: 6004736 (5.726562 MB) 6030536 (5.751167 MB) 1.00x

Wasm: 2429204 (2.316669 MB) 2300872 (2.194283 MB) 0.95x (probably noise)

YarrJIT: 1522488 (1.451958 MB) 1522616 (1.452080 MB) 1.00x

CSSJIT: 0 0

Uncategorized: 0 0

Cumulative diff since the start of this effort to put more code in JIT thunks:

Base New Diff

BaselineJIT: 89089964 (84.962811 MB) 72407904 (69.053558 MB) 0.81x (reduction)

DFG: 39117360 (37.305222 MB) 36622176 (34.925629 MB) 0.94x (reduction)

Thunk: 23230968 (22.154778 MB) 23295448 (22.216270 MB) 1.00x

InlineCache: 22027416 (21.006981 MB) 22157236 (21.130787 MB) 1.01x

FTL: 6575772 (6.271145 MB) 6030536 (5.751167 MB) 0.92x (reduction)

Wasm: 2302724 (2.196049 MB) 2300872 (2.194283 MB) 1.00x

YarrJIT: 1538956 (1.467663 MB) 1522616 (1.452080 MB) 0.99x

CSSJIT: 0 0

Uncategorized: 0 0

• assembler/MacroAssemblerX86_64.h:

(JSC::MacroAssemblerX86_64::sub64):

• jit/AssemblyHelpers.h:

(JSC::AssemblyHelpers::emitRestoreCalleeSavesFor):
(JSC::AssemblyHelpers::copyLLIntBaselineCalleeSavesFromFrameOrRegisterToEntryFrameCalleeSavesBuffer):
(JSC::AssemblyHelpers::copyCalleeSavesFromFrameOrRegisterToEntryFrameCalleeSavesBuffer): Deleted.

• jit/JIT.cpp:

(JSC::JIT::emitEnterOptimizationCheck):
(JSC::JIT::link):

• jit/JIT.h:

(JSC::NearJumpRecord::NearJumpRecord):

• jit/JITInlines.h:

(JSC::JIT::emitNakedNearJump):

• jit/JITOpcodes.cpp:

(JSC::JIT::emit_op_ret):
(JSC::JIT::op_ret_handlerGenerator):
(JSC::JIT::emit_op_throw):
(JSC::JIT::op_throw_handlerGenerator):
(JSC::JIT::emit_op_enter):
(JSC::JIT::op_enter_handlerGenerator):
(JSC::JIT::emitSlow_op_loop_hint):
(JSC::JIT::emitSlow_op_check_traps):
(JSC::JIT::op_check_traps_handlerGenerator):

• jit/JITPropertyAccess.cpp:

(JSC::JIT::slow_op_get_from_scopeGenerator):
(JSC::JIT::slow_op_put_to_scopeGenerator):

• jit/JITThunks.cpp:

(JSC::JITThunks::preinitializeExtraCTIThunks):

• jit/SlowPathCall.cpp:

(JSC::JITSlowPathCall::generateThunk):

File:

• trunk/Source/JavaScriptCore/jit/JIT.cpp (modified) (2 diffs)

trunk/Source/JavaScriptCore/jit/JIT.cpp

@@ -94 +94 @@
     ASSERT(!m_bytecodeIndex.offset());
 
-    copyCalleeSavesFromFrameOrRegisterToEntryFrameCalleeSavesBuffer(vm().topEntryFrame);
+    copyLLIntBaselineCalleeSavesFromFrameOrRegisterToEntryFrameCalleeSavesBuffer(vm().topEntryFrame);
 
     callOperation(operationOptimize, &vm(), m_bytecodeIndex.asBits());
@@ -905 +905 @@
 #endif
 
+    for (auto& record : m_nearJumps) {
+        if (record.target)
+            patchBuffer.link(record.from, record.target);
+    }
     for (auto& record : m_nearCalls) {
         if (record.callee)