Anyone? This looks like a trivial fix. -Aleksey
On 02/01/2016 10:47 PM, Aleksey Shipilev wrote: > Hi, > > Please review the fix for a corner case in StringConcatFactory exactness > check, which produces invalid bytecode: > https://bugs.openjdk.java.net/browse/JDK-8148787 > > Note that this happens when all three things align: > a) BSM is called directly, as Java method -- javac would never produce > such a String concat shape; > b) BC_SB_SIZED_EXACT strategy is used, so exactness check can be applied; > c) -Djava.lang.invoke.stringConcat.debug=true is set, forcing > exactness check to run; > > The issue is with exactness debug check using a temporary local variable > when the local variable table is small (like it is in non-arg case). The > code can be reformulated without using temporary variables, with a > creative use of "swap" instruction. > > Ironically, the bug is within the debugging code, so we don't care about > its performance at all: > http://cr.openjdk.java.net/~shade/8148787/webrev.01/ > > Cheers, > -Aleksey >
