Changeset 294794 in webkit for trunk/Source/JavaScriptCore/assembler/MacroAssemblerARMv7.h

Timestamp:

May 25, 2022, 6:32:59 AM (3 years ago)

Author:

[email protected]

Message:

[JSC][ARMv7] Support callee save FPRs

Patch by Geza Lore <Geza Lore> on 2022-05-25
​https://bugs.webkit.org/show_bug.cgi?id=240376

Reviewed by Yusuke Suzuki.

ARMv7 FPRs d8-d15 (also referenced as s16-s32 and q4-q7) are callee save
in the host ABI, but currently JSC is unaware of this. This does not
currently cause problems as they are not used, but will be used by the
Wasm JITs.

In preparation for the 32-bit ports of the Wasm JITs, this patch:

• Teaches JSC about callee save FPRs on ARMv7. d8-d15 are host ABI callee save, but only d8-d14 are VM callee save, i.e.: we treat d15 as a volatile register in JIT code. This is so we can use d15 as a macro assembler scratch register.
• Changes offlineasm and MacroAssemblerARMv7 to use d15 as the FP scratch register. We do this so we can use the full range of d0-d7 as temporary, and in particular as Wasm argument/return registers.
• To achieve the above, we need to modify RegisterAtOffsetList as GPRs and FPRs have different sizes on JSVALUE32_64 platforms
• Adds the ARMv7 specific registers to RegisterSet::macroScratchRegisters()

• assembler/ARMv7Registers.h:
• assembler/MacroAssemblerARMv7.h:
• b3/air/AirCode.cpp:

(JSC::B3::Air::Code::calleeSaveRegisterAtOffsetList const):
(JSC::B3::Air::Code::dump const):

• b3/testb3_7.cpp:

(testInfiniteLoopDoesntCauseBadHoisting):

• bytecode/CodeBlock.cpp:

(JSC::CodeBlock::llintBaselineCalleeSaveSpaceAsVirtualRegisters):
(JSC::CodeBlock::calleeSaveSpaceAsVirtualRegisters):
(JSC::roundCalleeSaveSpaceAsVirtualRegisters): Deleted.

• bytecode/ValueRecovery.h:

(JSC::ValueRecovery::calleeSaveGPRDisplacedInJSStack):
(JSC::ValueRecovery::calleeSaveRegDisplacedInJSStack): Deleted.

• dfg/DFGOSREntry.cpp:

(JSC::DFG::prepareOSREntry):

• dfg/DFGOSRExitCompilerCommon.cpp:

(JSC::DFG::calleeSaveSlot):

• ftl/FTLOSRExitCompiler.cpp:

(JSC::FTL::compileStub):

• interpreter/Interpreter.cpp:

(JSC::UnwindFunctor::copyCalleeSavesToEntryFrameCalleeSavesBuffer const):

• jit/AssemblyHelpers.cpp:

(JSC::AssemblyHelpers::restoreCalleeSavesFromEntryFrameCalleeSavesBuffer):
(JSC::AssemblyHelpers::restoreCalleeSavesFromVMEntryFrameCalleeSavesBufferImpl):
(JSC::AssemblyHelpers::copyCalleeSavesToEntryFrameCalleeSavesBufferImpl):
(JSC::AssemblyHelpers::emitSave):
(JSC::AssemblyHelpers::emitRestore):
(JSC::AssemblyHelpers::emitSaveCalleeSavesFor):
(JSC::AssemblyHelpers::emitRestoreCalleeSavesFor):
(JSC::AssemblyHelpers::copyLLIntBaselineCalleeSavesFromFrameOrRegisterToEntryFrameCalleeSavesBuffer):
(JSC::AssemblyHelpers::emitSaveOrCopyLLIntBaselineCalleeSavesFor):

• jit/CallFrameShuffleData.cpp:

(JSC::CallFrameShuffleData::setupCalleeSaveRegisters):

• jit/CallFrameShuffler.h:

(JSC::CallFrameShuffler::snapshot const):

• jit/CallFrameShuffler32_64.cpp:

(JSC::CallFrameShuffler::emitDisplace):

• jit/FPRInfo.h:
• jit/GPRInfo.h:
• jit/RegisterAtOffsetList.cpp:

(JSC::RegisterAtOffsetList::RegisterAtOffsetList):

• jit/RegisterAtOffsetList.h:

(JSC::RegisterAtOffsetList::registerCount const):
(JSC::RegisterAtOffsetList::sizeOfAreaInBytes const):
(JSC::RegisterAtOffsetList::adjustOffsets):
(JSC::RegisterAtOffsetList::size const): Deleted.
(JSC::RegisterAtOffsetList::at): Deleted.

• jit/RegisterSet.cpp:

(JSC::RegisterSet::macroScratchRegisters):
(JSC::RegisterSet::vmCalleeSaveRegisters):

• llint/LowLevelInterpreter.asm:
• offlineasm/arm.rb:
• wasm/js/JSToWasm.cpp:

(JSC::Wasm::createJSToWasmWrapper):

• wasm/js/WasmToJS.cpp:

(JSC::Wasm::wasmToJS):

• wasm/js/WebAssemblyFunction.cpp:

(JSC::WebAssemblyFunction::jsCallEntrypointSlow):

Canonical link: ​https://commits.webkit.org/250952@main

File:

• trunk/Source/JavaScriptCore/assembler/MacroAssemblerARMv7.h (modified) (1 diff)

trunk/Source/JavaScriptCore/assembler/MacroAssemblerARMv7.h

@@ -42 +42 @@
     static constexpr size_t nearJumpRange = 16 * MB;
 
-private:
     static constexpr RegisterID dataTempRegister = ARMRegisters::ip;
     static constexpr RegisterID addressTempRegister = ARMRegisters::r6;
 
-    static constexpr ARMRegisters::FPDoubleRegisterID fpTempRegister = ARMRegisters::d7;
+    // d15 is host/C ABI callee save, but is volatile in the VM/JS ABI. We use
+    // this as scratch register so we can use the full range of d0-d7 as
+    // temporary, and in particular as Wasm argument/return register.
+    static constexpr ARMRegisters::FPDoubleRegisterID fpTempRegister = ARMRegisters::d15;
+private:
     inline ARMRegisters::FPSingleRegisterID fpTempRegisterAsSingle() { return ARMRegisters::asSingle(fpTempRegister); }