[Ask for sponsoring] Fix another NPE in jdk.compiler/com.sun.tools.javac.jvm.Code.emitop0(Code.java:571)

[B. Blaser]

Hi,

On Sun, 20 Dec 2020 at 10:49, JiaYanwei <jiaywe at gmail.com> wrote:
>
> Hi all,
>
> I had found & fixed a javac issue like https://bugs.openjdk.java.net/browse/JDK-8229862 , and created a PR on Github: https://github.com/openjdk/jdk/pull/1479 .
>
> I have no account to create JIRA issue, and I'm not sure whether the code style as well as the solution itself are appropriate. Could anyone sponsor me? Thanks a lot.
>
> Best Regards.

The problem seems to be that 'lambdaTranslationMap' links the
untranslated local variable to its capture. So, what do you think of
the following solution to keep the translated local variable's mapping
with the original symbol (both examples and langtools:tier1 are OK on
jdk14u)?

Thanks,
Bernard

diff --git a/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/LambdaToMethod.java
b/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/LambdaToMethod.java
--- a/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/LambdaToMethod.java
+++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/LambdaToMethod.java
@@ -2057,7 +2057,13 @@
                         };
                         break;
                     case LOCAL_VAR:
-                        ret = new VarSymbol(sym.flags() & FINAL,
sym.name, sym.type, translatedSym);
+                        ret = new VarSymbol(sym.flags() & FINAL,
sym.name, sym.type, translatedSym) {
+                            @Override
+                            public Symbol baseSymbol() {
+                                //keep mapping with original symbol
+                                return sym;
+                            }
+                        };
                         ((VarSymbol) ret).pos = ((VarSymbol) sym).pos;
                         break;
                     case PARAM:
diff --git a/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Lower.java
b/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Lower.java
--- a/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Lower.java
+++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Lower.java
@@ -1221,7 +1221,7 @@
                 //sym is a local variable - check the lambda translation map to
                 //see if sym has been translated to something else in
the current
                 //scope (by LambdaToMethod)
-                Symbol translatedSym = lambdaTranslationMap.get(sym);
+                Symbol translatedSym =
lambdaTranslationMap.get(sym.baseSymbol());
                 if (translatedSym != null) {
                     tree = make.at(tree.pos).Ident(translatedSym);
                 }