RFR: 8264096: slowdebug jvm crashes when StrInflatedCopy match rule is not supported

[Tobias Hartmann]

On Wed, 24 Mar 2021 02:45:14 GMT, Fei Yang <fyang at openjdk.org> wrote:

> As shown on the bug, two JVM crashes are witnessed when running the provided test case after disabling match rule support for StrInflatedCopy.  
> 
> The cause for the first JVM crash is that we are calling has_match_rule for Op_StrInflatedCopy in is_intrinsic_supported.  
> In this case, we have match rule for Op_StrInflatedCopy but that match rule is not supported.  
> Patch fixed the first crash by changing the use of has_match_rule into match_rule_supported.  match_rule_supported  will check has_match_rule at entry point.  
> 
> In the case for the second JVM crash, the C2 code path is different when match rule for StrInflatedCopy is not supported.  
> In PhaseStringOpts::copy_latin1_string, we will call GraphKit::inflate_string_slow instread of GraphKit::inflate_string.  
> We emit one loop in GraphKit::inflate_string_slow, but the method is not marked may have some loops.  
> Looks like this is missed by JDK-8253923.  Patch fixed the second crash by setting _has_loops to true in GraphKit::inflate_string_slow.  
> 
> Testing: tier 1-3 tested with release & fastdebug build on x86_64 linux with match rule support for StrInflatedCopy explicitly disabled.

Looks good to me.

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Marked as reviewed by thartmann (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/3166