// bridgeRecoverFunc creates a function that may call recover(), and creates
// a call to it from the current frame. The created function will be called
// with a boolean parameter that indicates whether it may call recover().
//
// The created function will have the same name as the current frame's function
// with "$recover" appended, having the same return types and parameters with
// an additional boolean parameter appended.
//
// A new frame will be returned for the newly created function.
func (fr *frame) bridgeRecoverFunc(llfn llvm.Value, fti functionTypeInfo) *frame {
// The bridging function must not be inlined, or the return address
// may not correspond to the source function.
llfn.AddFunctionAttr(llvm.NoInlineAttribute)
// Call __go_can_recover, passing in the function's return address.
entry := llvm.AddBasicBlock(llfn, "entry")
fr.builder.SetInsertPointAtEnd(entry)
canRecover := fr.runtime.canRecover.call(fr, fr.returnAddress(0))[0]
returnType := fti.functionType.ReturnType()
argTypes := fti.functionType.ParamTypes()
argTypes = append(argTypes, canRecover.Type())
// Create and call the $recover function.
ftiRecover := fti
ftiRecover.functionType = llvm.FunctionType(returnType, argTypes, false)
llfnRecover := ftiRecover.declare(fr.module.Module, llfn.Name()+"$recover")
fr.addCommonFunctionAttrs(llfnRecover)
llfnRecover.SetLinkage(llvm.InternalLinkage)
args := make([]llvm.Value, len(argTypes)-1, len(argTypes))
for i := range args {
args[i] = llfn.Param(i)
}
args = append(args, canRecover)
result := fr.builder.CreateCall(llfnRecover, args, "")
if returnType.TypeKind() == llvm.VoidTypeKind {
fr.builder.CreateRetVoid()
} else {
fr.builder.CreateRet(result)
}
// The $recover function must condition calls to __go_recover on
// the result of __go_can_recover passed in as an argument.
fr = newFrame(fr.unit, llfnRecover)
fr.retInf = ftiRecover.retInf
fr.canRecover = fr.function.Param(len(argTypes) - 1)
return fr
}