[ORC][x64] Respect JITDUMP_USE_ARCH_TIMESTAMP environment variable

[topolarity]

This environment variable is set by perf record -e intel_pt to indicate that an arch-specific timestamp should be used when emitting the jitdump instead of CLOCK_MONOTONIC, which allows the dump to be correlated to the Intel PT recording data by perf inject --jit.

Without this change perf inject complains that the recording was taken improperly:

$ perf inject --jit --input perf.data --output perf.jit.data                  
error, jitted code must be sampled with perf record -k 1

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[gbaraldi]

Do you not need to change anything in JITLoaderPerf?

[topolarity]

Do you not need to change anything in JITLoaderPerf?

Thanks! I didn't notice there was another implementation that needed updating.

[topolarity]

Ping

[topolarity]

Ping