[Fwd: Request for review (S): CR 6889740 - G1: OpenDS fails with "unhandled exception in compiled code"]
Vladimir.Kozlov at Sun.COM
Tue Oct 27 17:19:23 PDT 2009
Thank you, John, for hunting down this difficult to find problem.
Changes looks good. Did you thought to use int32_t imm32
instead of intptr_t src?
I wonder if we have other places like this. For example,
the next code in generate_exception_handler_common()
uses NULL_WORD without casting to (int32_t):
__ movptr(c_rarg2, NULL_WORD);
but there is no void* dummy declaration for movptr():
void movptr(Register dst, intptr_t src);
void movptr(Register dst, Register src);
void movptr(Register dst, int32_t imm32);
#endif // _LP64
john cuthbertson - Sun Microsystems wrote:
> Hi Everyone,
> I should have included the compiler alias on the attached review
> request. Can someone look over the changes?
> -------- Original Message --------
> Subject: Request for review (S): CR 6889740 - G1: OpenDS fails with
> "unhandled exception in compiled code"
> Date: Tue, 27 Oct 2009 14:51:46 -0700
> From: john cuthbertson - Sun Microsystems <John.Cuthbertson at Sun.COM>
> To: hotspot-gc-dev at openjdk.java.net
> Hi Everyone,
> Can I have a couple of volunteers to review the proposed fix for this
> bug? The webrev can be found at
> The issue is that bad code was being generated for the store operation
> in the null case of the aastore bytecode template. The bad code was
> caused by there being only one version of the store_heap_oop routine
> that took a Register as the second argument. When the calling code
> passed in NULL_WORD (0) to this routine the value was used as a Register
> encoding and converted to Register(0), which is rax. Thus the generated
> store was "mov (dst), $rax" instead of "mov (dst), $0x0". This is
> normally not a problem as the preceding code in the template fetches the
> value to be stored into rax. When the G1 pre-barrier code calls the
> runtime, however, the value in rax can be overwritten and the heap can
> become corrupted.
> Testing: OpenDS, jprt, refworkload, and the GC test suite.
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