RFR: 8283643: [AIX, testbug] MachCodeFramesInErrorFile test fails to find 'Native frames' text

[Martin Doerr]

On Mon, 4 Apr 2022 15:47:06 GMT, Tyler Steele <duke at openjdk.java.net> wrote:

> I observed a failure of MachCodeFramesInErrorFile.java on AIX. The raised error complains that 'Native frames: ' is missing. To fix the failure, I made two changes to the test that allowed it to pass on AIX.
> 
> The first change made was to the test's `extractFrames` method. AIX overrides `os::platform_print_native_stack` with stack printing specific to AIX/Power. This code does not produce the 'Native frames: ' text that `vmError::print_native_stack` does, so the test was modified to expect the AIX output when run on AIX. 
> 
> A second change was made to the address passed to the `crashInNative1` method. AIX does not consider low-address memory to be protected as other platforms do. In fact, "the first 256 bytes are reserved for software use" according to the Power ISA. Accordingly, the read address for PPC was changed to -1 (0xFF..FF) to produce the expected failure result.
> 
> ### Testing
> 
> Tier1 tests complete as expected on AIX/Power.

Looks basically good to me, but please take a look at my comments.

test/hotspot/jtreg/runtime/ErrorHandling/MachCodeFramesInErrorFile.java line 75:

> 73:                 assert args[0].equals("crashInVM");
> 74:                 // AIX does not prohibit low address reads
> 75:                 crashInNative1( Platform.isPPC() ? -1 : 10 );

Spaces next to braces are uncommon.

test/hotspot/jtreg/runtime/ErrorHandling/MachCodeFramesInErrorFile.java line 177:

> 175:         } else {
> 176:             marker = (nativeStack ? "Native" : "Java") + " frames: ";
> 177:         }

Yeah, we have special stack trace code on AIX. Ok.

test/hotspot/jtreg/runtime/ErrorHandling/MachCodeFramesInErrorFile.java line 189:

> 187:             }
> 188:         }
> 189:         throw new RuntimeException("\"" + marker + "\" line missing in hs_err_pid file:\n");

Please explain removal!

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PR: https://git.openjdk.java.net/jdk/pull/8094