[9] RFR (M): 8160543: C1: Crash in java.lang.String.indexOf in some java.sql tests

[Nils Eliasson]

Hi,

This is fixes for bug [1] JDK-8160543 "C1: Crash in 
java.lang.String.indexOf in some java.sql tests" and [2] JDK-8154172 
"NPE is thrown instead of linkage error when invoking nonexistent method "

* Description:

Problem in bug #2: A method that is not loaded must not have null check 
at the call. The unloaded method may not exist and then we may throw a 
NPE on a null receiver before LinkageError and violate the VM spec.

Problem in bug #1: A final method that is not loaded at compile time 
(the final-property is unknown), but is actually loaded from another 
classloader (and may already be compiled) must null check its receiver. 
The null check can not be at the call site since it would violate #2. 
Instead the call will have to use the target methods unverified entry 
point.

An additional problem i encountered is that profiling requires a null 
check, but if the method isn't loaded we can't add one. So we can't 
profile unloaded methods.

The solution to these problems shouldn't introduce any regression in the 
normal use case. Unloaded methods is only common in the compiler when 
using -Xcomp when the interpreter hasn't made sure everything is loaded. 
I have made the trade-off that it is acceptable to have an performance 
regression in the -Xcomp case in order to meet the VM specification.

* Summary of changes:

hotspot/src/share/vm/code/compiledIC.cpp

-    if (static_bound || is_optimized) {
+    if (is_optimized) {

static_bound is true if the method at resolve time is declared final. 
This is uninteresting, we need to know if the call was known final at 
compile time. is_optimized however is only true if the targets was 
loaded and was final at compile time. This change makes sure that we get 
a call to the unverified entry point if there was no null check emitted.

hotspot/src/share/vm/c1/c1_GraphBuilder.cpp
Contains both changed and some simplifications. The is_resolved method 
has been exploded, and redundant check was removed. The major change is 
where we decide if a null check should be emitted and when profiling can 
be added.

* Testing

These are some useful test I have run with and without -Xcomp and with 
and without -XX:TieredStopAtLevel=1:
- jdk/test/java/sql/testng/test/sql/CallableStatementTests.java (for bug #1)
- JCK/BINC (binc02908m01 for bug #2 and all binc0500)
- hotspot/test/compiler/linkage/LinkageErrors.java

I will await complete runs of hs-comp tier 0 - 5 before checkin.

Please review,

Regards,
Nils Eliasson



Webrev: http://cr.openjdk.java.net/~neliasso/8160543/webrev.09/
Bug [1]: https://bugs.openjdk.java.net/browse/JDK-8160543
Bug [2]: https://bugs.openjdk.java.net/browse/JDK-8160383
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