[JSC][ARMv7] Support callee save FPRs

[gezalore]

60a5bb3

[JSC][ARMv7] Support callee save FPRs

Patch by Geza Lore <glore@igalia.com > 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
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@294794 268f45cc-cd09-0410-ab3c-d52691b4dbfc

[Constellation]

https://bugs.webkit.org/show_bug.cgi?id=240376

Reviewed by NOBODY (OOPS!).

ARMv7 FPRs d8-d15 (also referenced as s16-s32 and q4-q7) are callee
save, 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
• To achieve the above, we need to modify RegisterAtOffsetList as GPRs
  and FPRs have different sizes on JSVALUE32_64 platforms
• Changes offlineasm and MacroAssemblerARMv7 to use d15 as the FP
  scratch register

Can you describe why d15 is picked for FP scratch register?
It is callee-save register, and usually we pick caller-save register for scratch.

• 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):

[gezalore]

Can you describe why d15 is picked for FP scratch register? It is callee-save register, and usually we pick caller-save register for scratch.

I expanded the commit message to explain this. r? please.

[gezalore]

Fixed the other comments.

[Constellation]

r=me

[webkit-early-warning-system]

No reviewer information in commit message, blocking PR #777

[webkit-early-warning-system]

No reviewer information in commit message, blocking PR #777

[webkit-early-warning-system]

Committed r294794 (250952@main): https://commits.webkit.org/250952@main

Reviewed commits have been landed. Closing PR #777 and removing active labels.