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module RubyVM::MJIT
class ExitCompiler
def initialize
@gc_refs = [] # TODO: GC offsets?
end
# Used for invalidating a block on entry.
# @param pc [Integer]
# @param asm [RubyVM::MJIT::Assembler]
def compile_entry_exit(pc, ctx, asm, cause:)
# Increment per-insn exit counter
incr_insn_exit(pc, asm)
# Fix pc/sp offsets for the interpreter
save_pc_and_sp(pc, ctx, asm, reset_sp_offset: false)
# Restore callee-saved registers
asm.comment("#{cause}: entry exit")
asm.pop(SP)
asm.pop(EC)
asm.pop(CFP)
asm.mov(:rax, Qundef)
asm.ret
end
# Set to cfp->jit_return by default for leave insn
# @param asm [RubyVM::MJIT::Assembler]
def compile_leave_exit(asm)
asm.comment('default cfp->jit_return')
# Restore callee-saved registers
asm.pop(SP)
asm.pop(EC)
asm.pop(CFP)
# :rax is written by #leave
asm.ret
end
# Fire cfunc events on invalidation by TracePoint
# @param asm [RubyVM::MJIT::Assembler]
def compile_full_cfunc_return(asm)
# This chunk of code expects REG_EC to be filled properly and
# RAX to contain the return value of the C method.
asm.comment('full cfunc return')
asm.mov(C_ARG_OPNDS[0], EC)
asm.mov(C_ARG_OPNDS[1], :rax)
asm.call(C.rb_full_cfunc_return)
# TODO: count the exit
# Restore callee-saved registers
asm.pop(SP)
asm.pop(EC)
asm.pop(CFP)
asm.mov(:rax, Qundef)
asm.ret
end
# @param jit [RubyVM::MJIT::JITState]
# @param ctx [RubyVM::MJIT::Context]
# @param asm [RubyVM::MJIT::Assembler]
def compile_side_exit(jit, ctx, asm)
# Increment per-insn exit counter
incr_insn_exit(jit.pc, asm)
# Fix pc/sp offsets for the interpreter
save_pc_and_sp(jit.pc, ctx.dup, asm) # dup to avoid sp_offset update
# Restore callee-saved registers
asm.comment("exit to interpreter on #{pc_to_insn(jit.pc).name}")
asm.pop(SP)
asm.pop(EC)
asm.pop(CFP)
asm.mov(:rax, Qundef)
asm.ret
end
# @param ctx [RubyVM::MJIT::Context]
# @param asm [RubyVM::MJIT::Assembler]
# @param branch_stub [RubyVM::MJIT::BranchStub]
# @param target0_p [TrueClass,FalseClass]
def compile_branch_stub(ctx, asm, branch_stub, target0_p)
# Call rb_mjit_branch_stub_hit
asm.comment("branch stub hit: #{branch_stub.iseq.body.location.label}@#{C.rb_iseq_path(branch_stub.iseq)}:#{iseq_lineno(branch_stub.iseq, target0_p ? branch_stub.target0.pc : branch_stub.target1.pc)}")
asm.mov(:rdi, to_value(branch_stub))
asm.mov(:esi, ctx.sp_offset)
asm.mov(:edx, target0_p ? 1 : 0)
asm.call(C.rb_mjit_branch_stub_hit)
# Jump to the address returned by rb_mjit_stub_hit
asm.jmp(:rax)
end
private
def pc_to_insn(pc)
Compiler.decode_insn(C.VALUE.new(pc).*)
end
# @param pc [Integer]
# @param asm [RubyVM::MJIT::Assembler]
def incr_insn_exit(pc, asm)
if C.mjit_opts.stats
insn = Compiler.decode_insn(C.VALUE.new(pc).*)
asm.comment("increment insn exit: #{insn.name}")
asm.mov(:rax, (C.mjit_insn_exits + insn.bin).to_i)
asm.add([:rax], 1) # TODO: lock
end
end
# @param jit [RubyVM::MJIT::JITState]
# @param ctx [RubyVM::MJIT::Context]
# @param asm [RubyVM::MJIT::Assembler]
def save_pc_and_sp(pc, ctx, asm, reset_sp_offset: true)
# Update pc (TODO: manage PC offset?)
asm.comment("save PC#{' and SP' if ctx.sp_offset != 0} to CFP")
asm.mov(:rax, pc) # rax = jit.pc
asm.mov([CFP, C.rb_control_frame_t.offsetof(:pc)], :rax) # cfp->pc = rax
# Update sp
if ctx.sp_offset != 0
asm.add(SP, C.VALUE.size * ctx.sp_offset) # sp += stack_size
asm.mov([CFP, C.rb_control_frame_t.offsetof(:sp)], SP) # cfp->sp = sp
if reset_sp_offset
ctx.sp_offset = 0
end
end
end
def to_value(obj)
@gc_refs << obj
C.to_value(obj)
end
def iseq_lineno(iseq, pc)
C.rb_iseq_line_no(iseq, (pc - iseq.body.iseq_encoded.to_i) / C.VALUE.size)
end
end
end
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