Changeset 292540 in webkit for trunk/Source/JavaScriptCore/assembler/MacroAssemblerARMv7.h

Timestamp:

Apr 7, 2022, 10:03:19 AM (3 years ago)

Author:

[email protected]

Message:

[JSC][ARMv7] Support proper near calls and JUMP_ISLANDS
​https://bugs.webkit.org/show_bug.cgi?id=238143

Patch by Geza Lore <Geza Lore> on 2022-04-07
Reviewed by Yusuke Suzuki.

JSTests:

• microbenchmarks/let-const-tdz-environment-parsing-and-hash-consing-speed.js:

Source/JavaScriptCore:

Implement nearCall and nearTailCall as single instruction direct
branches on ARMv7/Thumb-2. (Will need to support these for Wasm JITs,
to implement threadSafePatchableNearcall.) To make this possible while
also having an executable pool size larger than the branch range, I
also ported JUMP_ISLANDS.

To port JUMP_ISLANDS, a reformulation of the region allocations was
necessary, which is now done in terms of the range of the
nearCall/nearTailCall macroassembler macros. For ARM64, the behaviour
should be identical.

The jump islad reservation on ARMv7 is set to 5% of executable memory
size, which is approximately the same as the baseline JIT code size
saving provided by using short branches for near calls, so the change
should be neutral overall with respect to executable memory
consumption.

Also made it possible for the --jitMemoryReservationSize option to
request JIT memory that is larger than the default hardcoded size
while using JUMP_ISLANDS (we need this for testing on ARMv7, which has
a smaller default executable pool size). To do this the region
allocators are no longer statically allocated but are held in a
FixedVector.

Also removed the unused repatchCompact methods from assemblers.

• assembler/ARM64Assembler.h:
• assembler/ARMv7Assembler.h:

(JSC::ARMv7Assembler::isEven):
(JSC::ARMv7Assembler::makeEven):
(JSC::ARMv7Assembler::bl):
(JSC::ARMv7Assembler::link):
(JSC::ARMv7Assembler::linkTailCall):
(JSC::ARMv7Assembler::linkCall):
(JSC::ARMv7Assembler::relinkCall):
(JSC::ARMv7Assembler::relinkTailCall):
(JSC::ARMv7Assembler::prepareForAtomicRelinkJumpConcurrently):
(JSC::ARMv7Assembler::prepareForAtomicRelinkCallConcurrently):
(JSC::ARMv7Assembler::replaceWithJump):
(JSC::ARMv7Assembler::canEmitJump):
(JSC::ARMv7Assembler::isBL):
(JSC::ARMv7Assembler::linkJumpT4):
(JSC::ARMv7Assembler::linkConditionalJumpT4):
(JSC::ARMv7Assembler::linkJumpAbsolute):
(JSC::ARMv7Assembler::linkBranch):

• assembler/AbstractMacroAssembler.h:

(JSC::AbstractMacroAssembler::repatchNearCall):

• assembler/AssemblerCommon.h:

(JSC::isInt):

• assembler/MIPSAssembler.h:
• assembler/MacroAssemblerARM64.h:
• assembler/MacroAssemblerARMv7.h:

(JSC::MacroAssemblerARMv7::nearCall):
(JSC::MacroAssemblerARMv7::nearTailCall):
(JSC::MacroAssemblerARMv7::linkCall):

• assembler/MacroAssemblerMIPS.h:
• assembler/MacroAssemblerRISCV64.h:
• assembler/MacroAssemblerX86Common.h:
• assembler/X86Assembler.h:
• bytecode/Repatch.cpp:

(JSC::linkPolymorphicCall):

• jit/ExecutableAllocator.cpp:

(JSC::initializeJITPageReservation):

Source/WTF:

Support constructor arguments for FixedVector element initialization.

• wtf/EmbeddedFixedVector.h:
• wtf/FixedVector.h:

(WTF::FixedVector::FixedVector):

• wtf/PlatformEnable.h:
• wtf/TrailingArray.h:

(WTF::TrailingArray::TrailingArray):

• wtf/Vector.h:

(WTF::VectorTypeOperations::initializeWithArgs):

File:

• trunk/Source/JavaScriptCore/assembler/MacroAssemblerARMv7.h (modified) (3 diffs)

trunk/Source/JavaScriptCore/assembler/MacroAssemblerARMv7.h

@@ -39 +39 @@
 
 class MacroAssemblerARMv7 : public AbstractMacroAssembler<Assembler> {
+public:
+    static constexpr size_t nearJumpRange = 16 * MB;
+
+private:
     static constexpr RegisterID dataTempRegister = ARMRegisters::ip;
     static constexpr RegisterID addressTempRegister = ARMRegisters::r6;
@@ -2238 +2242 @@
     ALWAYS_INLINE Call nearCall()
     {
-        moveFixedWidthEncoding(TrustedImm32(0), dataTempRegister);
         invalidateAllTempRegisters();
-        return Call(m_assembler.blx(dataTempRegister), Call::LinkableNear);
+        return Call(m_assembler.bl(), Call::LinkableNear);
     }
 
     ALWAYS_INLINE Call nearTailCall()
     {
-        moveFixedWidthEncoding(TrustedImm32(0), dataTempRegister);
         invalidateAllTempRegisters();
-        return Call(m_assembler.bx(dataTempRegister), Call::LinkableNearTail);
+        return Call(m_assembler.b(), Call::LinkableNearTail);
     }
 
@@ -2655 +2657 @@
     static void linkCall(void* code, Call call, FunctionPtr<tag> function)
     {
-        if (call.isFlagSet(Call::Tail))
-            ARMv7Assembler::linkJump(code, call.m_label, function.executableAddress());
+        if (!call.isFlagSet(Call::Near))
+            Assembler::linkPointer(code, call.m_label.labelAtOffset(-2), function.executableAddress());
+        else if (call.isFlagSet(Call::Tail))
+            Assembler::linkTailCall(code, call.m_label, function.executableAddress());
         else
-            ARMv7Assembler::linkCall(code, call.m_label, function.executableAddress());
+            Assembler::linkCall(code, call.m_label, function.executableAddress());
     }