Android's class library uses this to find out whether the VM supports
compareAndSwapLong natively. Avian does on all platforms, so we just
return true.
There's a small optimization in compileDirectInvoke which tries to
avoid generating calls to empty methods. However, this causes
problems for code which uses such a call to ensure a class is
initialized -- if we omit that call, the class may not be
initialized and any side effects of that initialization may not
happen when the program expects them to.
This commit ensures that the compiler only omits empty method calls
when the target class does not need initialization. It also removes
commented-out code in classpath-openjdk.cpp which was responsible for
loading libmawt proactively; that was a hack to get JogAmp to work
before we understood what the real problem was.
Previously, we used "lzma:", which worked fine on Windows (where the
path separator is ";") but not on Unix-style OSes (where the path
separator is ":"). In the latter case, the VM would parse
"[lzma:bootJar]" as a path containing two elements, "[lzma" and
"bootJar]", which is not what was intended. So now we use "lzma." as
the prefix, which works on all OSes.
armv7 and later provide weaker cache coherency models than armv6 and
earlier, so we cannot just implement memory barriers as no-ops. This
patch uses the DMB instruction (or the equivalent OS-provided barrier
function) to implement barriers. This should fix concurrency issues
on newer chips such as the Apple A6 and A7.
If you still need to support ARMv6 devices, you should pass
"armv6=true" to make when building Avian. Ideally, the VM would
detect what kind of CPU it was executing on at runtime and direct the
JIT compiler accordingly, but I don't know how to do that on ARM.
Patches are welcome, though!
When calculating field offsets in the bootimage generator, we failed
to consider alignment at inheritence boundaries (i.e. the last field
inherited by from a superclass should be followed by enough padding to
align the first non-inherited field at a machine word boundary). This
led to a mismatch between native code and Java code in terms of class
layouts, including that of java.lang.reflect.Method.
