Review Request: 8005178: build-infra: Dependency on libfdlibm on mac is broken

[Erik Joelsson]

Oh, I will explain it.

So, on all other platforms, this is the dependency chain (simplified, 
skipping the actual recipe rules):

BUILD_LIBFDLIBM:=/path/to/libfdlibm.a
BUILD_LIBJAVA:=/path/to/libjava.so
$(BUILD_LIBJAVA): $(BUILD_LIBFDLIBM)

This forces the linking of libjava to happen after libfdlibm is created.

On mac there was a complication:

BUILD_LIBFDLIBM:=/path/to/temp/location/for/libfdlibm.a
/path/to/libfdlibm.a: $(BUILD_LIBFDLIBM)
$(BUILD_LIBJAVA): $(BUILD_LIBFDLIBM)

The recipe for BUILD_LIBJAVA looks for libfdlibm.a in 
/path/to/libfdlibm.a and not in the temp location. This results in a 
race condition where the copy of libfdlibm.a might not have happened 
before linking of libjava.

My fix does this:

BUILD_LIBFDLIBM_MAC:=/path/to/temp/location/for/libfdlibm.a
BUILD_LIBFDLIBM:=/path/to/libfdlibm.a
$(BUILD_LIBFDLIBM): $(BUILD_LIBFDLIBM_MAC)
$(BUILD_LIBJAVA): $(BUILD_LIBFDLIBM)

The difference is that the variable BUILD_LIBFDLIBM now points to the 
final location of libfdlibm.a on all platforms so the dependency is 
correct on all platforms.

There are other ways to solve this of course, but I prefer to minimize 
differences between platforms if possible.

/Erik

On 2012-12-19 02:04, Kelly O'Hair wrote:
> I'm assuming that the issue is that a static library is an additive thing, AR will add to it, while
> a shared library is created from scratch each time.
>
> It's possible that another fix is actually in the NativeCompilation.gmk file where the static library
> is created.
>
> But I'm curious too, hopefully Erik will set us straight in a few hours after he wakes up. ;^)
>
> -kto
>
> On Dec 18, 2012, at 3:38 PM, David Holmes wrote:
>
>> I don't understand the fix. Other than a name change this just seems to be "re-arranging the deckchairs". What is the actual function change ??
>>
>> David
>>
>> On 19/12/2012 1:55 AM, Erik Joelsson wrote:
>>> Was asked to fix the comment, new webrev:
>>>
>>> http://cr.openjdk.java.net/~erikj/8005178/webrev.jdk.02/
>>>
>>> On 2012-12-18 16:35, Erik Joelsson wrote:
>>>> This fixes a problem with make dependencies from libjava to libfdlibm
>>>> which causes intermittent build failures on mac.
>>>>
>>>> http://cr.openjdk.java.net/~erikj/8005178/webrev.jdk.01/