Files test fails with latest openjdk 7

[readytalk]

Files test fails with latest openjdk 7

[joshuawarner32]

Turns out this is because of a recent change in the jdk7 dev branch:

changeset: 5501:bcba89ce0a8c
user: sla
date: Tue Nov 27 09:23:54 2012 +0100
summary: 8003322: Add instrumentation points for tracing of I/O calls

The change replaced the read()| native method with a read0()|, and implemented read()I to defer to read0()I, with some instrumentation.

The fix to make avian compatible is simple:

diff --git a/src/classpath-openjdk.cpp b/src/classpath-openjdk.cpp
index 0cf5e3b..b8173d3 100644
--- a/src/classpath-openjdk.cpp
+++ b/src/classpath-openjdk.cpp
@@ -2002,7 +2002,7 @@ interceptFileOperations(Thread* t, bool updateRuntimeData)
         intercept(t, fileInputStreamClass, "open", "(Ljava/lang/String;)V",
                   voidPointer(openFile), updateRuntimeData);

-        intercept(t, fileInputStreamClass, "read", "()I",
+        intercept(t, fileInputStreamClass, "read0", "()I",
                   voidPointer(readByteFromFile), updateRuntimeData);

         intercept(t, fileInputStreamClass, "readBytes", "([BII)I",

The trick will be making avian compatible with both the old version and the new version of openjdk.

[joshuawarner32]

@dicej, any thoughts on how we can fix this, while (hopefully) maintaining compatibility with both versions?

[dicej]

On Fri, 6 Dec 2013, Joshua Warner wrote:

@dicej, any thoughts on how we can fix this, while (hopefully) maintaining
compatibility with both versions?

The intercept function will just do nothing if it can't find the method,
so we should be able to just have two calls to intercept: one for read and
another for read0.

[joshuawarner32]

The read()I method will always be present - the difference is whether it's a native method (old) or a Java method that delegates to read0()I.

The current implementation of intercept won't work because it doesn't pay any attention to the ACC_NATIVE flag; in fact, it unconditionally sets it.

[dicej]

On Fri, 6 Dec 2013, Joshua Warner wrote:

The read()I method will always be present - the difference is whether it's a
native method (old) or a Java method that delegates to read0()I.

The current implementation of intercept won't work because it doesn't pay
any attention to the ACC_NATIVE flag; in fact, it unconditionally sets it.

Then call findMethodOrNull before calling intercept to see if it's native
or not.

[joshuawarner32]

That would make too much sense. (mild face palm)

Expect a pull request coming your way soon...