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  1. JDK
  2. JDK-8247743

Segmentation fault in debug builds due to stack overflow in find_recur with deep graphs

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    • Resolved In Build:
      b07

      Description

      The attached test case results in a segmentation fault with a debug build with the following command line:
      java -Xcomp -XX:CompileCommand=option,Test::main,uintx,VectorizeDebug,65 -XX:CompileCommand=compileonly,Test::main Test.java

      The test was adapted from compiler/loopopts/TestDeepGraphVerifyIterativeGVN.java to also trigger the super word optimization. By additionally specifying the VectorizeDebug option, the code calls SuperWord::print_loop() -> PhaseIdealLoop::dump() -> C->root()->find(k) which then finally calls the recursive method find_recur(). Since the IR contains a lot of nodes in a chain, find_recur() calls itself recursively over and over again - eventually resulting in a stack overflow segmentation fault (similar to JDK-8246203). The suggested fix is the same as in JDK-8246203 to change the recursive algorithm into an iterative one.

      Log:
      CompileCommand: option Test.main uintx VectorizeDebug = 65
      CompileCommand: compileonly Test.main
      SuperWord::construct_bb: List of generations: 0:15 1:12 2:11 3:8 4:7 5:4 6:3 7:0
      SuperWord::mark_generations
      First generation (15) nodes:
       33821 CountedLoop === 33821 33170 2871 [[ 33785 33792 33799 33801 33820 33821 33699 33824 33706 38 33633 33166 ]] {33171:15} inner stride: 8 main of N33821 strip mined !orig=[33716],[33641],[33171],[33161],[1840] !jvms: Test::main @ bci:2349
       33820 Phi === 33821 33560 1841 [[ 33848 33816 33817 33818 33819 33831 1841 33840 33844 ]] {809:15} #int:1..51:www #tripcount !orig=[33719],33645,[809],[8459] !jvms: Test::main @ bci:2349
       33818 ConvI2L === _ 33820 [[ 33807 ]] {5680:15} #long:1..50:www !orig=[33718],[33644],[5680],[3676] !jvms: Test::main @ bci:2349
       33807 LShiftL === _ 33818 3677 [[ 33804 33806 ]] {3652:15} !orig=[33712],[33639],[3652],[2892] !jvms: Test::main @ bci:2349
       33804 AddP === _ 813 813 33807 [[ 33803 ]] {2877:15} !orig=[33709],[33636],[2877] !jvms: Test::main @ bci:2349
       33803 AddP === _ 813 33804 1859 [[ 33802 ]] {1848:15} !orig=33708,33635,1848 !jvms: Test::main @ bci:2349
       33806 AddP === _ 817 817 33807 [[ 33805 ]] {1858:15} !orig=[33711],[33638],[1858] !jvms: Test::main @ bci:2349
       33805 AddP === _ 817 33806 1859 [[ 33801 ]] {829:15} !orig=33710,33637,829 !jvms: Test::main @ bci:2349
       33824 Phi === 33821 33533 38 [[ 33801 33802 ]] {828:15} #memory Memory: @int[int:>=0]:exact+any *, idx=6; !orig=33722,33640,828,[50861],[50760] !jvms: Test::main @ bci:2353
       33802 LoadI === 33559 33824 33803 [[ 33801 ]] {815:15} @int[int:>=0]:exact+any *, idx=6; #int !orig=33707,33634,815 !jvms: Test::main @ bci:2349
       33801 StoreI === 33821 33824 33805 33802 [[ 33799 33800 ]] {38:15} @int[int:>=0]:exact+any *, idx=6; Memory: @int[int:>=0]:NotNull:exact+any *, idx=6; !orig=33706,33633,38,33650 !jvms: Test::main @ bci:2349
      Last generation (0) nodes:
       33848 ConvI2L === _ 33820 [[ 33856 ]] #long:1..46:www
       33856 LShiftL === _ 33848 3677 [[ 33864 33862 ]]
       33864 AddP === _ 817 817 33856 [[ 33710 ]]
       33862 AddP === _ 813 813 33856 [[ 33708 ]] !jvms: Test::main @ bci:2361
       33831 ConvI2L === _ 33820 [[ 33835 ]] #long:1..44:www
       33835 LShiftL === _ 33831 3677 [[ 33839 33837 ]]
       33839 AddP === _ 817 817 33835 [[ 33637 ]] !jvms: Test::main @ bci:2353
       33837 AddP === _ 813 813 33835 [[ 33635 ]]
       1841 AddI === _ 33820 16818 [[ 33550 33164 33820 33172 ]] {1841:0} !orig=[33163],... !jvms: Test::main @ bci:123
       33164 CmpI === _ 1841 33784 [[ 33165 ]] {33164:0} !orig=[1853] !jvms: Test::main @ bci:2307
       33165 Bool === _ 33164 [[ 33166 ]] {33165:0} [lt] !orig=[819] !jvms: Test::main @ bci:2307
       33840 ConvI2L === _ 33820 [[ 33852 ]] #long:1..45:www !jvms: Test::main @ bci:2353
       33852 LShiftL === _ 33840 3677 [[ 33859 33858 ]]
       33859 AddP === _ 817 817 33852 [[ 33703 ]]
       33858 AddP === _ 813 813 33852 [[ 33701 ]]
       33844 ConvI2L === _ 33820 [[ 33854 ]] #long:1..43:www
       33854 LShiftL === _ 33844 3677 [[ 33861 33860 ]]
       33861 AddP === _ 817 817 33854 [[ 829 ]] !jvms: Test::main @ bci:2361
       829 AddP === _ 817 33861 33865 [[ 38 ]] {829:0} !jvms: Test::main @ bci:53
       33860 AddP === _ 813 813 33854 [[ 1848 ]] !jvms: Test::main @ bci:2361
       1848 AddP === _ 813 33860 33865 [[ 815 ]] {1848:0} !jvms: Test::main @ bci:123
       815 LoadI === 33559 33633 1848 [[ 38 ]] {815:0} @int[int:>=0]:exact+any *, idx=6; #int !jvms: Test::main @ bci:53
       38 StoreI === 33821 33633 829 815 [[ 33824 1851 33552 ]] {38:0} @int[int:>=0]:exact+any *, idx=6; Memory: @int[int:>=0]:NotNull:exact+any *, idx=6; !orig=33650 !jvms: Test::main @ bci:2343
       
      SuperWord::List of generations: 0:15 1:12 2:11 3:8 4:7 5:4 6:3 7:0
      SuperWord::hoist_loads_in_graph: total number _mem_slice_head.length() = 1
      SuperWord::hoist_loads_in_graph: processing phi 33824 = _mem_slice_head.at(0);
      SuperWord::hoist_loads_in_graph: will try to hoist load ld2->_idx=33800, cloned from 815 (ld->_idx=33802)
      SuperWord::hoist_loads_in_graph: will try to hoist load ld2->_idx=33795, cloned from 815 (ld->_idx=33802)
      SuperWord::hoist_loads_in_graph: will try to hoist load ld2->_idx=33788, cloned from 815 (ld->_idx=33802)
      SuperWord::hoist_loads_in_graph: will try to hoist load ld2->_idx=33707, cloned from 815 (ld->_idx=33802)
      SuperWord::hoist_loads_in_graph: will try to hoist load ld2->_idx=33700, cloned from 815 (ld->_idx=33802)
      SuperWord::hoist_loads_in_graph: will try to hoist load ld2->_idx=33634, cloned from 815 (ld->_idx=33802)
      SuperWord::hoist_loads_in_graph: will try to hoist load ld2->_idx=815, cloned from 815 (ld->_idx=33802)
      SuperWord::first_node: 33802 is the first iteration node for 33800 (_clone_map.idx(nnn->_idx) = 815)
      SuperWord::hoist_loads_in_graph replacing MemNode::Memory(1) edge in 33800 with one from 33824
      SuperWord::first_node: 33802 is the first iteration node for 33795 (_clone_map.idx(nnn->_idx) = 815)
      SuperWord::hoist_loads_in_graph replacing MemNode::Memory(1) edge in 33795 with one from 33824
      SuperWord::first_node: 33802 is the first iteration node for 33788 (_clone_map.idx(nnn->_idx) = 815)
      SuperWord::hoist_loads_in_graph replacing MemNode::Memory(1) edge in 33788 with one from 33824
      SuperWord::first_node: 33802 is the first iteration node for 33707 (_clone_map.idx(nnn->_idx) = 815)
      SuperWord::hoist_loads_in_graph replacing MemNode::Memory(1) edge in 33707 with one from 33824
      SuperWord::first_node: 33802 is the first iteration node for 33700 (_clone_map.idx(nnn->_idx) = 815)
      SuperWord::hoist_loads_in_graph replacing MemNode::Memory(1) edge in 33700 with one from 33824
      SuperWord::first_node: 33802 is the first iteration node for 33634 (_clone_map.idx(nnn->_idx) = 815)
      SuperWord::hoist_loads_in_graph replacing MemNode::Memory(1) edge in 33634 with one from 33824
      SuperWord::first_node: 33802 is the first iteration node for 815 (_clone_map.idx(nnn->_idx) = 815)
      SuperWord::hoist_loads_in_graph replacing MemNode::Memory(1) edge in 815 with one from 33824
      SuperWord::construct_bb: List of generations: 0:15 1:12 2:11 3:8 4:7 5:4 6:3 7:0
      SWPointer::output: print loop before create_reserve_version_of_loop
          Loop: N33821/N2871 counted [int,43),+8 (2147483648 iters) main has_sfpt strip_mined
          C ID:33170 33821 CountedLoop === 33821 33170 2871 [[ 33785 33792 33799 33801 33820 33821 33699 33824 33706 38 33633 33166 ]] {33171:15} inner stride: 8 main of N33821 strip mined !orig=[33716],[33641],[33171],[33161],[1840] !jvms: Test::main @ bci:2349
      Segmentation fault (core dumped)

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              Assignee:
              chagedorn Christian Hagedorn
              Reporter:
              chagedorn Christian Hagedorn
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                Updated:
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