Review Request: 8008451: Make mac builds on 10.8 work on 10.7

[Tao Mao]

Please reply to this thread to make sure all interested parties can see it.
Tao

On 2/20/2013 11:53 AM, John Coomes wrote:
> Erik Joelsson (erik.joelsson at oracle.com) wrote:
>> I was wrong, just setting the macros below did not generate 10.7
>> compatible bits when built on 10.8. Since I already pushed the old
>> solution (except for hotspot), I created a new bug. Here is a new set of
>> patches, combining -DMAC_OS_X_VERSION_MAX_ALLOWED=1070 and
>> -mmacosx-version-min=10.7.0 and also setting the latter on the link
>> command line. This combination both generates compatible binaries and
>> treats newer API calls as errors, all verified.
>>
>> Sine the two parameters take their argument in different formats, the
>> handling of defaults is a bit more complicated. The variable being sent
>> around and that you can override on the command line is now
>> MACOSX_VERSION_MIN=10.7.0, matching the parameter to the compiler/linker.
>>
>> It would be good if someone from hotspot could review the hotspot changes.
>>
>> http://cr.openjdk.java.net/~erikj/8008451/webrev.hotspot.01/
> The hotspot changes look good to me.
>
> -John
>
>> http://cr.openjdk.java.net/~erikj/8008451/webrev.root.01/
>> http://cr.openjdk.java.net/~erikj/8008451/webrev.jdk.01/
>>
>> /Erik
>>
>> On 2013-02-15 10:49, Erik Joelsson wrote:
>>>
>>> On 2013-02-15 09:43, Erik Joelsson wrote:
>>>> On 2013-02-14 18:04, David DeHaven wrote:
>>>>>> Here are a series of patches that adds the following to all native
>>>>>> compile lines on macosx:
>>>>>>
>>>>>> -DMAC_OS_X_VERSION_MAX_ALLOWED=1070
>>>>>> -DMAC_OS_X_VERSION_MIN_REQUIRED=1070
>>>>> I know I'm not a reviewer, but I have an opinion anyways :)
>>>>>
>>>>> Using "-mmacosx-version-min=10.7" seems more appropriate for the
>>>>> latter, this is passed to the linker as well which I believe sets
>>>>> version information in the Mach-O headers (in the form of a load
>>>>> command) to prevent it from being loaded on older systems. The
>>>>> MIN_REQUIRED macro is set to a value that matches what's passed to
>>>>> the -mmacosx-version-min argument, so it doesn't need to be provided.
>>>>>
>>>>>
>>>> The effect of the -mmacosx-version-min=10.7 when sent to the linker
>>>> is to make any calls to newer APIs "softlinked". This means the
>>>> library will still load fine on the older OS, but the application is
>>>> responsible for only actually making the newer calls if they are
>>>> available. This is a good feature if you knowingly want to support
>>>> multiple versions of the OS and still use features in the newer OS
>>>> when available. I do not believe we have the need for that and if we
>>>> ever do, then these parameters will need to change.
>>>>
>>> It's true -mmacosx-version-min= also sets the macro
>>> MAC_OS_X_VERSION_MIN_REQUIRED=, but I see no gain in changing just one
>>> of them to something else just because it works. The format of the
>>> parameter is also different (10.7 vs 1070) which would require us to
>>> add logic for converting between the two.
>>>
>>> /Erik