gistfile1.txt

% ruby -e 'p(begin; raise; rescue => e; end)'
nil
% ruby187 -e 'p(begin; raise; rescue => e; end)'
RuntimeError
% jruby --1.9 -e 'p(begin; raise; rescue => e; end)'
RuntimeError
% jruby --1.8 -e 'p(begin; raise; rescue => e; end)'
RuntimeError
% jruby -J-Xbootclasspath/a:$JRUBY_HOME/build_lib/jgrapht-jdk1.5.jar -X-CIR -e 'p(begin; raise; rescue => e; end)'
RuntimeError
% rbx -e 'p(begin; raise; rescue => e; end)'    
nil

% ruby --dump=parsetree -e 'begin; raise; rescue => e; end'
###########################################################
## Do NOT use this node dump for any purpose other than  ##
## debug and research.  Compatibility is not guaranteed. ##
###########################################################

# @ NODE_SCOPE (line: 1)
# +- nd_tbl: :e
# +- nd_args:
# |   (null node)
# +- nd_body:
#     @ NODE_RESCUE (line: 1)
#     +- nd_head:
#     |   @ NODE_BLOCK (line: 1)
#     |   +- nd_head:
#     |   |   @ NODE_BEGIN (line: 1)
#     |   |   +- nd_body:
#     |   |       (null node)
#     |   +- nd_next:
#     |       @ NODE_BLOCK (line: 1)
#     |       +- nd_head:
#     |       |   @ NODE_VCALL (line: 1)
#     |       |   +- nd_mid: :raise
#     |       +- nd_next:
#     |           (null node)
#     +- nd_resq:
#     |   @ NODE_RESBODY (line: 1)
#     |   +- nd_args:
#     |   |   (null node)
#     |   +- nd_body:
#     |   |   @ NODE_BLOCK (line: 1)
#     |   |   +- nd_head:
#     |   |   |   @ NODE_DASGN_CURR (line: 1)
#     |   |   |   +- nd_vid: :e
#     |   |   |   +- nd_value:
#     |   |   |       @ NODE_ERRINFO (line: 1)
#     |   |   +- nd_next:
#     |   |       @ NODE_BLOCK (line: 1)
#     |   |       +- nd_head:
#     |   |       |   @ NODE_BEGIN (line: 1)
#     |   |       |   +- nd_body:
#     |   |       |       (null node)
#     |   |       +- nd_next:
#     |   |           (null node)
#     |   +- nd_head:
#     |       (null node)
#     +- nd_else:
#         (null node)

% jruby -S ast -s -e 'begin; raise; rescue => e; end'
AST:
RootNode 0
  NewlineNode 0
    BeginNode 0
      RescueNode 0
        RescueBodyNode 0
          LocalAsgnNode:e 0
            GlobalVarNode:$! 0
        NewlineNode 0
          VCallNode:raise 0

SEXP:
(root (newline (begin (rescue (rescuebody (localasgn e (globalvar $!))) (newline (vcall raise))))))

% jruby -J-Xbootclasspath/a:$JRUBY_HOME/build_lib/jgrapht-jdk1.5.jar -X-CIR -Xir.debug=true -e 'begin; raise; rescue => e; end'
[snip]
Instructions:
BB [1:LBL_4]
BB [2:LBL_5]
        %self = recv_self
        %block(0:0) = recv_closure
        file_name(-e)
        line_num(0)
BB [3:LBL_0]
        %v_1 = call(raise, %self, [])
        %v_0 = copy(%v_1)
BB [4:LBL_2]
        %v_2 = recv_exception
        %v_3 = get_global_var($!)
        e(0:1) = copy(%v_3)
        %v_0 = copy(%v_3)
        jump LBL_1
BB [5:LBL_1]
        return(%v_0)
BB [6:LBL_6]
        return(nil)


------ Rescue block map ------
BB 3 --> BB 4


------ Ensure block map ------

% rbx compile -SB -e 'begin; raise; rescue => e; end' 
[:script,
 [:rescue,
  [:call, nil, :raise, nil],
  [:resbody,
   [:array, [:const, :StandardError], [:lasgn, :e, [:gvar, :$!]]],
   [:nil]]]]

============= :__script__ ==============
Arguments:   0 required, 0 post, 0 total
Arity:       0
Locals:      1: e
Stack size:  6
Lines to IP: 1: 0..12, 0: 13..17, 1: 18..43, 0: 44..49

0000:  push_exception_state       
0001:  set_stack_local            0
0003:  pop                        
0004:  setup_unwind               13, 0
0007:  push_self                  
0008:  send_method                :raise
0010:  pop_unwind                 
0011:  goto                       44
0013:  push_exception_state       
0014:  set_stack_local            1
0016:  pop                        
0017:  push_current_exception     
0018:  dup_top                    
0019:  push_const_fast            :StandardError, 2
0022:  swap_stack                 
0023:  send_stack                 :===, 1
0026:  goto_if_true               30
0028:  goto                       39
0030:  pop                        
0031:  push_current_exception     
0032:  set_local                  0    # e
0034:  pop                        
0035:  push_nil                   
0036:  clear_exception            
0037:  goto                       44
0039:  pop                        
0040:  push_stack_local           1
0042:  restore_exception_state    
0043:  reraise                    
0044:  push_stack_local           0
0046:  restore_exception_state    
0047:  pop                        
0048:  push_true                  
0049:  ret                        
----------------------------------------