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  1. JDK
  2. JDK-8264096

slowdebug jvm crashes when StrInflatedCopy match rule is not supported

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    • Subcomponent:
    • Resolved In Build:
      b16
    • CPU:
      generic
    • OS:
      generic

      Backports

        Description

        $ cat Test.java
        class Test {

            public static String concatStringConstU(String a) {
                return new StringBuilder().append(stringSmallU).append(a).append(stringU).toString();
            }

            static final String stringU = "\u0f21\u0f22\u0f23\u0f24\u0f25\u0f26\u0f27\u0f28";
            static final String stringSmallU = "\u0f21\u0f22\u0f23";

            public static void main(String args[]){
                String a = "ABC";
                Test t = new Test();
                for (int i = 0; i < 100_000; i++){
                    t.concatStringConstU(a);
                }
            }

        }

        Disable StrInflatedCopy match rule support for x86 with following trivial change and build a slowdebug jdk on x86_64 Linux:

        diff --git a/src/hotspot/cpu/x86/x86.ad b/src/hotspot/cpu/x86/x86.ad
        index 7cf669f0e27..84d3e38125b 100644
        --- a/src/hotspot/cpu/x86/x86.ad
        +++ b/src/hotspot/cpu/x86/x86.ad
        @@ -1461,6 +1461,8 @@ const bool Matcher::match_rule_supported(int opcode) {
                 return false;
               }
               break;
        + case Op_StrInflatedCopy:
        + return false;
             case Op_OnSpinWait:
               if (VM_Version::supports_on_spin_wait() == false) {
                 return false;


        $ ~/github/jdk-upstream/build/linux-x86_64-server-slowdebug/jdk/bin/java -XX:-BackgroundCompilation -XX:CICompilerCount=2 Test

        1. First JVM crash log
          1 #
          2 # A fatal error has been detected by the Java Runtime Environment:
          3 #
          4 # Internal Error (/home/yangfei/github/jdk-upstream/src/hotspot/share/opto/graphKit.cpp:4215), pid=21009, tid=21104
          5 # assert(Matcher::match_rule_supported(Op_StrInflatedCopy)) failed: Intrinsic not supported
          6 #
          7 # JRE version: OpenJDK Runtime Environment (17.0) (slowdebug build 17-internal+0-adhoc.yangfei.jdk-upstream)
          8 # Java VM: OpenJDK 64-Bit Server VM (slowdebug 17-internal+0-adhoc.yangfei.jdk-upstream, mixed mode, tiered, compressed oops, compressed class ptrs, g1 gc, linux-amd64)
          9 # Problematic frame:
         10 # V [libjvm.so+0xa6c41c] GraphKit::inflate_string(Node*, Node*, TypeAryPtr const*, Node*)+0x3a
         11 #
         12 # Core dump will be written. Default location: Core dumps may be processed with "/usr/share/apport/apport %p %s %c %d %P %E" (or dumping to /h ome/yangfei/c2/core.21009)
         13 #
         14 # If you would like to submit a bug report, please visit:
         15 # https://bugreport.java.com/bugreport/crash.jsp
         16 #
         17
         18 --------------- S U M M A R Y ------------
         19
         20 Command Line: -XX:-BackgroundCompilation -XX:CICompilerCount=2 Test
         21
         22 Host: ubuntu18, Intel(R) Xeon(R) CPU E5-2690 v3 @ 2.60GHz, 48 cores, 377G, Ubuntu 18.04.2 LTS
         23 Time: Wed Mar 24 09:57:06 2021 CST elapsed time: 6.732316 seconds (0d 0h 0m 6s)
         24
         25 --------------- T H R E A D ---------------
         26
         27 Current thread (0x00007f7e1045efa0): JavaThread "C2 CompilerThread0" daemon [_thread_in_native, id=21104, stack(0x00007f7da9160000,0x00007f7d a9261000)]
         28
         29
         30 Current CompileTask:
         31 C2: 6732 417 b 4 java.lang.AbstractStringBuilder::append (45 bytes)
         32
         33 Stack: [0x00007f7da9160000,0x00007f7da9261000], sp=0x00007f7da925bc60, free space=1007k
         34 Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
         35 V [libjvm.so+0xa6c41c] GraphKit::inflate_string(Node*, Node*, TypeAryPtr const*, Node*)+0x3a
         36 V [libjvm.so+0xdb1000] LibraryCallKit::inline_string_copy(bool)+0x552
         37 V [libjvm.so+0xdac345] LibraryCallKit::try_to_inline(int)+0x4c3
         38 V [libjvm.so+0xdab236] LibraryIntrinsic::generate(JVMState*)+0x188
         39 V [libjvm.so+0x9026d8] Parse::do_call()+0xb80
         40 V [libjvm.so+0x10070c3] Parse::do_one_bytecode()+0x45e1
         41 V [libjvm.so+0xff5068] Parse::do_one_block()+0x4dc
         42 V [libjvm.so+0xff146f] Parse::do_all_blocks()+0x3bd
         43 V [libjvm.so+0xff0fb3] Parse::Parse(JVMState*, ciMethod*, float)+0x100b
         44 V [libjvm.so+0x6c75d4] ParseGenerator::generate(JVMState*)+0x106
         ......

        Proposed patch fixed the first crash by this change:

        diff --git a/src/hotspot/share/opto/c2compiler.cpp b/src/hotspot/share/opto/c2compiler.cpp
        index 89b0270ab72..f2b9e3ecd6d 100644
        --- a/src/hotspot/share/opto/c2compiler.cpp
        +++ b/src/hotspot/share/opto/c2compiler.cpp
        @@ -179,11 +179,11 @@ bool C2Compiler::is_intrinsic_supported(const methodHandle& method, bool is_virt
           switch (id) {
           case vmIntrinsics::_compressStringC:
           case vmIntrinsics::_compressStringB:
        - if (!Matcher::has_match_rule(Op_StrCompressedCopy)) return false;
        + if (!Matcher::match_rule_supported(Op_StrCompressedCopy)) return false;
             break;
           case vmIntrinsics::_inflateStringC:
           case vmIntrinsics::_inflateStringB:
        - if (!Matcher::has_match_rule(Op_StrInflatedCopy)) return false;
        + if (!Matcher::match_rule_supported(Op_StrInflatedCopy)) return false;
             break;
           case vmIntrinsics::_compareToL:
           case vmIntrinsics::_compareToU:

        2. Second jvm crash log
          1 #
          2 # A fatal error has been detected by the Java Runtime Environment:
          3 #
          4 # Internal Error (/home/yangfei/github/jdk-upstream/src/hotspot/share/opto/loopnode.cpp:3790), pid=16853, tid=16868
          5 # assert(_ltree_root->_child == __null || C->has_loops() || only_has_infinite_loops() || C->has_exception_backedge()) failed: parsing found no loops but there are some
          6 #
          7 # JRE version: OpenJDK Runtime Environment (17.0) (slowdebug build 17-internal+0-adhoc.yangfei.jdk-upstream)
          8 # Java VM: OpenJDK 64-Bit Server VM (slowdebug 17-internal+0-adhoc.yangfei.jdk-upstream, mixed mode, tiered, compressed oops, compressed class ptrs, g1 gc, linux-amd64)
          9 # Problematic frame:
         10 # V [libjvm.so+0xe14d0e] PhaseIdealLoop::build_and_optimize(LoopOptsMode)+0x334
         11 #
         12 # Core dump will be written. Default location: Core dumps may be processed with "/usr/share/apport/apport %p %s %c %d %P %E" (or dumping to /h ome/yangfei/c2/core.16853)
         13 #
         14 # If you would like to submit a bug report, please visit:
         15 # https://bugreport.java.com/bugreport/crash.jsp
         16 #
         17
         18 --------------- S U M M A R Y ------------
         19
         20 Command Line: -XX:-BackgroundCompilation -XX:CICompilerCount=2 Test
         21
         22 Host: ubuntu18, Intel(R) Xeon(R) CPU E5-2690 v3 @ 2.60GHz, 48 cores, 377G, Ubuntu 18.04.2 LTS
         23 Time: Wed Mar 24 10:02:49 2021 CST elapsed time: 4.423882 seconds (0d 0h 0m 4s)
         24
         25 --------------- T H R E A D ---------------
         26
         27 Current thread (0x00007f39f445efa0): JavaThread "C2 CompilerThread0" daemon [_thread_in_native, id=16868, stack(0x00007f398ab5d000,0x00007f39 8ac5e000)]
         28
         29
         30 Current CompileTask:
         31 C2: 4423 421 b 4 Test::concatStringConstU (25 bytes)
         32
         33 Stack: [0x00007f398ab5d000,0x00007f398ac5e000], sp=0x00007f398ac58120, free space=1004k
         34 Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
         35 V [libjvm.so+0xe14d0e] PhaseIdealLoop::build_and_optimize(LoopOptsMode)+0x334
         36 V [libjvm.so+0x7e9c96] PhaseIdealLoop::PhaseIdealLoop(PhaseIterGVN&, LoopOptsMode)+0x10e
         37 V [libjvm.so+0x7e9eae] PhaseIdealLoop::optimize(PhaseIterGVN&, LoopOptsMode)+0x46
         38 V [libjvm.so+0x7dcd79] Compile::optimize_loops(PhaseIterGVN&, LoopOptsMode)+0xf7
         39 V [libjvm.so+0x7ddc8c] Compile::Optimize()+0xd6e
         40 V [libjvm.so+0x7d6bd6] Compile::Compile(ciEnv*, ciMethod*, int, bool, bool, bool, bool, DirectiveSet*)+0x13e4
         41 V [libjvm.so+0x6c563e] C2Compiler::compile_method(ciEnv*, ciMethod*, int, bool, DirectiveSet*)+0x128
         42 V [libjvm.so+0x7f3ac3] CompileBroker::invoke_compiler_on_method(CompileTask*)+0x889
         43 V [libjvm.so+0x7f26e7] CompileBroker::compiler_thread_loop()+0x3dd
         44 V [libjvm.so+0x815377] CompilerThread::thread_entry(JavaThread*, Thread*)+0x69
         45 V [libjvm.so+0x1273a9b] JavaThread::thread_main_inner()+0x14f
         46 V [libjvm.so+0x1273944] JavaThread::run()+0x11e
         47 V [libjvm.so+0x1270f72] Thread::call_run()+0x180
         48 V [libjvm.so+0xfbda2e] thread_native_entry(Thread*)+0x1e4

        Proposed patch fixed the second crash by this change:

        diff --git a/src/hotspot/share/opto/graphKit.cpp b/src/hotspot/share/opto/graphKit.cpp
        index 69e3c4fa9dd..22078bdbff4 100644
        --- a/src/hotspot/share/opto/graphKit.cpp
        +++ b/src/hotspot/share/opto/graphKit.cpp
        @@ -4228,6 +4228,8 @@ void GraphKit::inflate_string_slow(Node* src, Node* dst, Node* start, Node* coun
            * }
            */
           add_empty_predicates();
        + C->set_has_loops(true);
        +
           RegionNode* head = new RegionNode(3);
           head->init_req(1, control());
           gvn().set_type(head, Type::CONTROL);

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                Assignee:
                fyang Fei Yang
                Reporter:
                fyang Fei Yang
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                  Created:
                  Updated:
                  Resolved: