RFR: 8311879: ClassWriter generates invalid invokedynamic code

[Chen Liang]

On Wed, 12 Jul 2023 13:49:17 GMT, Daohan Qu <dqu at openjdk.org> wrote:

> This patch should fix the wrong CP index for `invokedynamic` instruction generated by SA's `ClassWriter`. The buggy code in `sun.jvm.hotspot.tools.jcore.ByteCodeRewriter` should have been up-to-date with the following code snippet in `hotspot`:
> 
> https://github.com/openjdk/jdk/blob/753bd563ecca6bb5ff9b5ebc0957bc1854dce78d/src/hotspot/share/interpreter/rewriter.cpp#L291-L294
> 
> The comments above seem to be obsolete since the following change made in [JDK-8301995](https://bugs.openjdk.org/browse/JDK-8301995). So I also remove them.
> 
> 
> +    // Should do nothing since we are not patching this bytecode
>      int cache_index = ConstantPool::decode_invokedynamic_index(
>                          Bytes::get_native_u4(p));
>      // We will reverse the bytecode rewriting _after_ adjusting them.
>      // Adjust the cache index by offset to the invokedynamic entries in the
>      // cpCache plus the delta if the invokedynamic bytecodes were adjusted.
> -    int adjustment = cp_cache_delta() + _first_iteration_cp_cache_limit;
> -    int cp_index = invokedynamic_cp_cache_entry_pool_index(cache_index - adjustment);
> +    int cp_index = _initialized_indy_entries.at(cache_index).constant_pool_index();
>      assert(_pool->tag_at(cp_index).is_invoke_dynamic(), "wrong index");
> 
> 
> This fix is straightforward and thank @asotona for finding this bug!
> 
> ### Test Results of release build on Linux x64
> * `jtreg:test/hotspot/jtreg/serviceability` and `jtreg:test/jdk/sun/tools/`: PASS
> * `tier1`: PASS
> * `tier2` and `tier3`: Running

src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/tools/jcore/ByteCodeRewriter.java line 106:

> 104:           cpCacheIndex = bytes.swapInt(cpCacheIndex);
> 105:           short cpIndex = (short) cpCache.getIndyEntryAt(cpCacheIndex).getConstantPoolIndex();
> 106:           if (!cpool.getTagAt(cpIndex).isInvokeDynamic()) {

Should this be an assertion instead?

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PR Review Comment: https://git.openjdk.org/jdk/pull/14852#discussion_r1261343881