func (i insnAddr32) op(code gen.OpCoder, addr int32) {
var offset int32
if addr != 0 {
siteAddr := code.Len() + i.size()
offset = addr - siteAddr
} else {
offset = -i.size() // infinite loop as placeholder
}
i.writeTo(code, offset)
}
func (opcode insnAddr8) op(code gen.OpCoder, addr int32) (ok bool) {
insnSize := int32(len(opcode)) + 1
siteAddr := code.Len() + insnSize
offset := addr - siteAddr
if offset >= -0x80 && offset < 0x80 {
code.Write(opcode)
code.WriteByte(uint8(offset))
ok = true
}
return
}
func (mach X86) OpInit(code gen.OpCoder, startAddr int32) (retAddr int32) {
if code.Len() == 0 || code.Len() > functionAlignment {
panic("inconsistency")
}
code.Align(functionAlignment, paddingByte)
Add.opImm(code, types.I64, regStackLimit, gen.StackReserve)
var notResume links.L
Test.opFromReg(code, types.I64, regResult, regResult)
Je.rel8.opStub(code)
notResume.AddSite(code.Len())
Ret.op(code) // simulate return from snapshot function call
notResume.Addr = code.Len()
mach.updateBranches8(code, ¬Resume)
CallRel.op(code, startAddr)
return code.Len()
}
func (i insnAddr32) opMissingFunction(code gen.OpCoder) {
siteAddr := code.Len() + i.size()
i.writeTo(code, -siteAddr)
}
func (i insnAddr8) opStub(code gen.OpCoder) {
i.op(code, code.Len()) // infinite loop as placeholder
}