double call on array store; possible bug in branch front end?

Sun Mar 10 15:34:00 GMT 2002

I've been banging my head against the wall all day over
this.... Observe the two Java snippets below, (CASE1 and CASE2). The
only difference is that CASE 2 assigns the return value to an array
element.
For some strange reason, the disassembly for CASE2 includes *two*
calls to generateFunctionICode. When you run it, it actually invokes
the method twice. I'm using -O0 on mingw/i86, 3.1 branch from two days
ago, plus the two patches for the two outstanding mingw PRs and the
pending patch to boehm-gc.
Is this a bug? If it is likely to be a bug, I can construct a small
test case, but that's likely to require a good bit of work (this is
deep down in the guts of Rhino, the Mozilla JS compiler), so I'd
appreciate a little bit of pre-screening before I go through the
effort (thanks).
 - a
______________________________________________________________________________
CASE 1:
 private void generateNestedFunctions(Scriptable scope,
 Context cx,
 Object securityDomain)
 {
 new Interpreter().generateFunctionICode(cx, scope,
 (FunctionNode)itsFunctionList.elementAt(0),
 securityDomain);
 }
00000812 <__ZN3org7mozilla10javascript11Interpreter23generateNestedFunctionsEPNS1_10ScriptableEPNS1_7ContextEPN4java4lang6ObjectE>:
 812: 55 push %ebp
 813: 89 e5 mov %esp,%ebp
 815: 53 push %ebx
 816: 83 ec 24 sub 0ドルx24,%esp
 819: c7 04 24 c0 04 00 00 movl 0ドルx4c0,(%esp,1)
 820: c7 44 24 04 44 00 00 movl 0ドルx44,0x4(%esp,1)
 827: 00 
 828: e8 00 00 00 00 call 82d <__ZN3org7mozilla10javascript11Interpreter23generateNestedFunctionsEPNS1_10ScriptableEPNS1_7ContextEPN4java4lang6ObjectE+0x1b>
 82d: 89 c3 mov %eax,%ebx
 82f: 89 1c 24 mov %ebx,(%esp,1)
 832: e8 d3 f2 00 00 call fb0a <__ZN3org7mozilla10javascript11InterpreterC1Ev>
 837: 89 5d f8 mov %ebx,0xfffffff8(%ebp)
 83a: 83 7d f8 00 cmpl 0ドルx0,0xfffffff8(%ebp)
 83e: 75 05 jne 845 <__ZN3org7mozilla10javascript11Interpreter23generateNestedFunctionsEPNS1_10ScriptableEPNS1_7ContextEPN4java4lang6ObjectE+0x33>
 840: e8 00 00 00 00 call 845 <__ZN3org7mozilla10javascript11Interpreter23generateNestedFunctionsEPNS1_10ScriptableEPNS1_7ContextEPN4java4lang6ObjectE+0x33>
 845: 8b 45 08 mov 0x8(%ebp),%eax
 848: 8b 40 14 mov 0x14(%eax),%eax
 84b: 8b 10 mov (%eax),%edx
 84d: 81 c2 a4 00 00 00 add 0ドルxa4,%edx
 853: 89 04 24 mov %eax,(%esp,1)
 856: c7 44 24 04 00 00 00 movl 0ドルx0,0x4(%esp,1)
 85d: 00 
 85e: 8b 02 mov (%edx),%eax
 860: ff d0 call *%eax
 862: c7 04 24 00 00 00 00 movl 0ドルx0,(%esp,1)
 869: 89 44 24 04 mov %eax,0x4(%esp,1)
 86d: e8 00 00 00 00 call 872 <__ZN3org7mozilla10javascript11Interpreter23generateNestedFunctionsEPNS1_10ScriptableEPNS1_7ContextEPN4java4lang6ObjectE+0x60>
 872: 89 c2 mov %eax,%edx
 874: 8b 45 f8 mov 0xfffffff8(%ebp),%eax
 877: 89 04 24 mov %eax,(%esp,1)
 87a: 8b 45 10 mov 0x10(%ebp),%eax
 87d: 89 44 24 04 mov %eax,0x4(%esp,1)
 881: 8b 45 0c mov 0xc(%ebp),%eax
 884: 89 44 24 08 mov %eax,0x8(%esp,1)
 888: 89 54 24 0c mov %edx,0xc(%esp,1)
 88c: 8b 45 14 mov 0x14(%ebp),%eax
 88f: 89 44 24 10 mov %eax,0x10(%esp,1)
 893: e8 06 00 00 00 call 89e <__ZN3org7mozilla10javascript11Interpreter21generateFunctionICodeEPNS1_7ContextEPNS1_10ScriptableEPNS1_12FunctionNodeEPN4java4lang6ObjectE>
 898: 83 c4 24 add 0ドルx24,%esp
 89b: 5b pop %ebx
 89c: 5d pop %ebp
 89d: c3 ret 
______________________________________________________________________________
CASE 2:
 private void generateNestedFunctions(Scriptable scope,
 Context cx,
 Object securityDomain)
 {
 itsNestedFunctions[0] = new Interpreter().generateFunctionICode(cx, scope,
 (FunctionNode)itsFunctionList.elementAt(0),
 securityDomain);
 }
00000812 <__ZN3org7mozilla10javascript11Interpreter23generateNestedFunctionsEPNS1_10ScriptableEPNS1_7ContextEPN4java4lang6ObjectE>:
 812: 55 push %ebp
 813: 89 e5 mov %esp,%ebp
 815: 53 push %ebx
 816: 83 ec 24 sub 0ドルx24,%esp
 819: 8b 45 08 mov 0x8(%ebp),%eax
 81c: 8b 40 34 mov 0x34(%eax),%eax
 81f: 89 45 f8 mov %eax,0xfffffff8(%ebp)
 822: 8b 45 f8 mov 0xfffffff8(%ebp),%eax
 825: 83 78 08 00 cmpl 0ドルx0,0x8(%eax)
 829: 75 0c jne 837 <__ZN3org7mozilla10javascript11Interpreter23generateNestedFunctionsEPNS1_10ScriptableEPNS1_7ContextEPN4java4lang6ObjectE+0x25>
 82b: c7 04 24 00 00 00 00 movl 0ドルx0,(%esp,1)
 832: e8 00 00 00 00 call 837 <__ZN3org7mozilla10javascript11Interpreter23generateNestedFunctionsEPNS1_10ScriptableEPNS1_7ContextEPN4java4lang6ObjectE+0x25>
 837: c7 04 24 c0 04 00 00 movl 0ドルx4c0,(%esp,1)
 83e: c7 44 24 04 44 00 00 movl 0ドルx44,0x4(%esp,1)
 845: 00 
 846: e8 00 00 00 00 call 84b <__ZN3org7mozilla10javascript11Interpreter23generateNestedFunctionsEPNS1_10ScriptableEPNS1_7ContextEPN4java4lang6ObjectE+0x39>
 84b: 89 c3 mov %eax,%ebx
 84d: 89 1c 24 mov %ebx,(%esp,1)
 850: e8 35 f3 00 00 call fb8a <__ZN3org7mozilla10javascript11InterpreterC1Ev>
 855: 89 5d f4 mov %ebx,0xfffffff4(%ebp)
 858: 83 7d f4 00 cmpl 0ドルx0,0xfffffff4(%ebp)
 85c: 75 05 jne 863 <__ZN3org7mozilla10javascript11Interpreter23generateNestedFunctionsEPNS1_10ScriptableEPNS1_7ContextEPN4java4lang6ObjectE+0x51>
 85e: e8 00 00 00 00 call 863 <__ZN3org7mozilla10javascript11Interpreter23generateNestedFunctionsEPNS1_10ScriptableEPNS1_7ContextEPN4java4lang6ObjectE+0x51>
 863: 8b 45 08 mov 0x8(%ebp),%eax
 866: 8b 40 14 mov 0x14(%eax),%eax
 869: 8b 10 mov (%eax),%edx
 86b: 81 c2 a4 00 00 00 add 0ドルxa4,%edx
 871: 89 04 24 mov %eax,(%esp,1)
 874: c7 44 24 04 00 00 00 movl 0ドルx0,0x4(%esp,1)
 87b: 00 
 87c: 8b 02 mov (%edx),%eax
 87e: ff d0 call *%eax
 880: 89 45 f0 mov %eax,0xfffffff0(%ebp)
 883: c7 04 24 00 00 00 00 movl 0ドルx0,(%esp,1)
 88a: 8b 55 f0 mov 0xfffffff0(%ebp),%edx
 88d: 89 54 24 04 mov %edx,0x4(%esp,1)
 891: e8 00 00 00 00 call 896 <__ZN3org7mozilla10javascript11Interpreter23generateNestedFunctionsEPNS1_10ScriptableEPNS1_7ContextEPN4java4lang6ObjectE+0x84>
 896: 89 c2 mov %eax,%edx
 898: 8b 45 f4 mov 0xfffffff4(%ebp),%eax
 89b: 89 04 24 mov %eax,(%esp,1)
 89e: 8b 45 10 mov 0x10(%ebp),%eax
 8a1: 89 44 24 04 mov %eax,0x4(%esp,1)
 8a5: 8b 45 0c mov 0xc(%ebp),%eax
 8a8: 89 44 24 08 mov %eax,0x8(%esp,1)
 8ac: 89 54 24 0c mov %edx,0xc(%esp,1)
 8b0: 8b 45 14 mov 0x14(%ebp),%eax
 8b3: 89 44 24 10 mov %eax,0x10(%esp,1)
 8b7: e8 60 00 00 00 call 91c <__ZN3org7mozilla10javascript11Interpreter21generateFunctionICodeEPNS1_7ContextEPNS1_10ScriptableEPNS1_12FunctionNodeEPN4java4lang6ObjectE>
 8bc: 8b 55 f8 mov 0xfffffff8(%ebp),%edx
 8bf: 89 14 24 mov %edx,(%esp,1)
 8c2: 89 44 24 04 mov %eax,0x4(%esp,1)
 8c6: e8 00 00 00 00 call 8cb <__ZN3org7mozilla10javascript11Interpreter23generateNestedFunctionsEPNS1_10ScriptableEPNS1_7ContextEPN4java4lang6ObjectE+0xb9>
 8cb: 83 7d f4 00 cmpl 0ドルx0,0xfffffff4(%ebp)
 8cf: 75 05 jne 8d6 <__ZN3org7mozilla10javascript11Interpreter23generateNestedFunctionsEPNS1_10ScriptableEPNS1_7ContextEPN4java4lang6ObjectE+0xc4>
 8d1: e8 00 00 00 00 call 8d6 <__ZN3org7mozilla10javascript11Interpreter23generateNestedFunctionsEPNS1_10ScriptableEPNS1_7ContextEPN4java4lang6ObjectE+0xc4>
 8d6: c7 04 24 00 00 00 00 movl 0ドルx0,(%esp,1)
 8dd: 8b 45 f0 mov 0xfffffff0(%ebp),%eax
 8e0: 89 44 24 04 mov %eax,0x4(%esp,1)
 8e4: e8 00 00 00 00 call 8e9 <__ZN3org7mozilla10javascript11Interpreter23generateNestedFunctionsEPNS1_10ScriptableEPNS1_7ContextEPN4java4lang6ObjectE+0xd7>
 8e9: 89 c2 mov %eax,%edx
 8eb: 8b 45 f4 mov 0xfffffff4(%ebp),%eax
 8ee: 89 04 24 mov %eax,(%esp,1)
 8f1: 8b 45 10 mov 0x10(%ebp),%eax
 8f4: 89 44 24 04 mov %eax,0x4(%esp,1)
 8f8: 8b 45 0c mov 0xc(%ebp),%eax
 8fb: 89 44 24 08 mov %eax,0x8(%esp,1)
 8ff: 89 54 24 0c mov %edx,0xc(%esp,1)
 903: 8b 45 14 mov 0x14(%ebp),%eax
 906: 89 44 24 10 mov %eax,0x10(%esp,1)
 90a: e8 0d 00 00 00 call 91c <__ZN3org7mozilla10javascript11Interpreter21generateFunctionICodeEPNS1_7ContextEPNS1_10ScriptableEPNS1_12FunctionNodeEPN4java4lang6ObjectE>
 90f: 8b 55 f8 mov 0xfffffff8(%ebp),%edx
 912: 89 42 0c mov %eax,0xc(%edx)
 915: 83 c4 24 add 0ドルx24,%esp
 918: 5b pop %ebx
 919: 5d pop %ebp
 91a: c3 ret 
 91b: 90 nop