RFR(M): 8204240: Extend MDO to allow more reasons to be recorded per bci

[Doerr, Martin]

Hi Roland,

that helps. Unfortunately, there's a second place which breaks 32 bit:
jdk/src/hotspot/share/runtime/threadHeapSampler.cpp(50) : warning C4293: '<<' : shift count negative or too big, undefined behavior

I'll open a bug and fix both ones.

Best regards,
Martin


-----Original Message-----
From: Roland Westrelin [mailto:rwestrel at redhat.com] 
Sent: Montag, 18. Juni 2018 14:27
To: Doerr, Martin <martin.doerr at sap.com>; hotspot-compiler-dev at openjdk.java.net
Subject: RE: RFR(M): 8204240: Extend MDO to allow more reasons to be recorded per bci


Hi Martin,

> we just noticed that this change causes a build warning on Windows 32 bit:
> jdk\src\hotspot\share\oops/methodData.hpp(142) : warning C4293: '<<' : shift count negative or too big, undefined behavior
>
> I think trap_mask is incorrect for 32 bit and should get fixed.

Thanks for reporting that issue. What about the patch below?

Roland.

diff --git a/src/hotspot/share/oops/methodData.hpp b/src/hotspot/share/oops/methodData.hpp
--- a/src/hotspot/share/oops/methodData.hpp
+++ b/src/hotspot/share/oops/methodData.hpp
@@ -139,7 +139,7 @@
     //
     // The trap_state is collected only if ProfileTraps is true.
     trap_bits = 1+31,  // 31: enough to distinguish [0..Reason_RECORDED_LIMIT].
-    trap_mask = right_n_bits(trap_bits),
+    trap_mask = -1,
     first_flag = 0
   };