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List:       openjdk-hotspot-compiler-dev
Subject:    Re: RFR: 8231955: ARM32: Address displacement is 0 for volatile field access because of Unsafe field
From:       christoph.goettschkes () microdoc ! com
Date:       2019-10-31 9:12:05
Message-ID: 20191031091347.9A008B109D () aojmv0009
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> I see now that BarrierSetC1::resolve_address() is calling 
> generate_address(), at least when access isn't patched.  So now I'm 
> thinking that the address passed to 
> volatile_field_load/volatile_field_store should be correct, and the call 

> to add_large_constant() isn't necessary.

Yes, this is correct. The LIR_Address is created by
LIRGenerator::generate_address and has a displacement of 0.
I attached a backtrace of the failing assert at the end of this mail.

Do you think the patch makes sense and can be pushed?
The HotSpot tier1 JTreg tests are passing with this and other patches I am 
working on applied with a debug VM.

-- Christoph

#0  0x7636b860 in LIRGenerator::add_large_constant
    (this=0x641ae2f0, src=0xe500b, c=0, dest=0xe900b)
    at src/hotspot/cpu/arm/c1_LIRGenerator_arm.cpp:166
#1  0x7636f266 in LIRGenerator::volatile_field_load
    (this=0x641ae2f0, address=0x6429c970, result=0xdd093, info=0x0) 
    at src/hotspot/cpu/arm/c1_LIRGenerator_arm.cpp:1326
#2  0x762d9806 in BarrierSetC1::load_at_resolved
    (this=0x7602b1f0, access=..., result=0xdd093)
    at src/hotspot/share/gc/shared/c1/barrierSetC1.cpp:183
#3  0x762d929a in BarrierSetC1::load_at 
    (this=0x7602b1f0, access=..., result=0xdd093)
    at src/hotspot/share/gc/shared/c1/barrierSetC1.cpp:94
#4  0x7635f6cc in LIRGenerator::access_load_at
    (this=0x641ae2f0, decorators=9127331840, type=T_LONG, base=...,
     offset=0xd900b, result=0xdd093, patch_info=0x0, load_emit_info=0x0)
    at src/hotspot/share/c1/c1_LIRGenerator.cpp:1618
#5  0x7636133e in LIRGenerator::do_UnsafeGetObject
    (this=0x641ae2f0, x=0x6429a0d0)
    at src/hotspot/share/c1/c1_LIRGenerator.cpp:2173
#6  0x76328bdc in UnsafeGetObject::visit
    (this=0x6429a0d0, v=0x641ae2f0)
    at src/hotspot/share/c1/c1_Instruction.hpp:2407
#7  0x7635b2d2 in LIRGenerator::do_root
    (this=0x641ae2f0, instr=0x6429a0d0)
    at src/hotspot/share/c1/c1_LIRGenerator.cpp:373
#8  0x7635b1f2 in LIRGenerator::block_do
    (this=0x641ae2f0, block=0x64299788)
    at src/hotspot/share/c1/c1_LIRGenerator.cpp:354
#9  0x76337d5a in BlockList::iterate_forward
    (this=0x6429bf00, closure=0x641ae2f4)
    at src/hotspot/share/c1/c1_Instruction.cpp:921
#10 0x76332936 in IR::iterate_linear_scan_order
    (this=0x642994d0, closure=0x641ae2f4) 
    at src/hotspot/share/c1/c1_IR.cpp:1221
#11 0x7630ed10 in Compilation::emit_lir
    (this=0x641ae5c0)
    at src/hotspot/share/c1/c1_Compilation.cpp:259
#12 0x7630f2be in Compilation::compile_java_method
    (this=0x641ae5c0) 
    at src/hotspot/share/c1/c1_Compilation.cpp:398
#13 0x7630f566 in Compilation::compile_method
    (this=0x641ae5c0)
    at src/hotspot/share/c1/c1_Compilation.cpp:460
#14 0x7630fabc in Compilation::Compilation
    (this=0x641ae5c0, compiler=0x760eb610, env=0x641ae848,
     method=0x63d2edc8, osr_bci=-1, buffer_blob=0x73eb7448,
     directive=0x760cf858)
    at src/hotspot/share/c1/c1_Compilation.cpp:583
#15 0x76312d6e in Compiler::compile_method
    (this=0x760eb610, env=0x641ae848, method=0x63d2edc8, entry_bci=-1,
     directive=0x760cf858)
    at src/hotspot/share/c1/c1_Compiler.cpp:247
#16 0x76453704 in CompileBroker::invoke_compiler_on_method
    (task=0x642cfa50)
    at src/hotspot/share/compiler/compileBroker.cpp:2115
#17 0x764529ba in CompileBroker::compiler_thread_loop
    ()
    at src/hotspot/share/compiler/compileBroker.cpp:1800
#18 0x7693548c in compiler_thread_entry
    (thread=0x6423b400, __the_thread__=0x6423b400)
    at src/hotspot/share/runtime/thread.cpp:3401
#19 0x769315d4 in JavaThread::thread_main_inner
    (this=0x6423b400)
    at src/hotspot/share/runtime/thread.cpp:1917
#20 0x769314ac in JavaThread::run
    (this=0x6423b400)
    at src/hotspot/share/runtime/thread.cpp:1900
#21 0x7692e884 in Thread::call_run
    (this=0x6423b400)
    at src/hotspot/share/runtime/thread.cpp:398
#22 0x768285ce in thread_native_entry
    (thread=0x6423b400)
    at src/hotspot/os/linux/os_linux.cpp:790
#23 0x76f84568 in start_thread() from target:/usr/lib/libpthread.so.0
#24 0x76ef8ac8 in ?? () from target:/usr/lib/libc.so.6

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