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August 27, 2008 [Issue 2318] New: flaw code generation building a function pointer table | ||||
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 | http://d.puremagic.com/issues/show_bug.cgi?id=2318 Summary: flaw code generation building a function pointer table Product: D Version: 1.034 Platform: PC OS/Version: Windows Status: NEW Severity: normal Priority: P2 Component: DMD AssignedTo: bugzilla@digitalmars.com ReportedBy: enzo.petrelli@fastwebnet.it /*************************** OS: Vista SP1 Compiler/linker: Digital Mars D Compiler v1.034 Tango/tangobos Lib: tango-0.99.7-bin-win32-dmd.1.033 Compiled with: dmd -g -debug epfuntbl.d Debug version: Trying to build a table of 5 function pointers out of 5 struct members, 1st and 3rd items are uncorrectly asssigned values Release version: A similar but slightly different behaviour is shown. Further, an "Access violation" is raised ***************************/ import std.cstream; alias void function() FnPtr; void initTTest(TTest * pTst) { // pTst.pVtbl = cast(void*) pTst.apFnc.ptr; pTst.apFnc[0] = cast(FnPtr) &pTst.func0; pTst.apFnc[1] = cast(FnPtr) &pTst.func1; pTst.apFnc[2] = cast(FnPtr) &pTst.func2; pTst.apFnc[3] = cast(FnPtr) &pTst.func3; pTst.apFnc[4] = cast(FnPtr) &pTst.func4; } struct TTest { void * pVtbl; FnPtr[5] apFnc; void func0() { dout.writefln("func0"); } void func1() { dout.writefln("func1"); } void func2() { dout.writefln("func2"); } void func3() { dout.writefln("func3"); } void func4() { dout.writefln("func4"); } } void main() { TTest * pTst = new TTest; initTTest(pTst); for (int iIdx = 0; iIdx < pTst.apFnc.length; ++iIdx) dout.writefln("item#%d:0x%08X", iIdx, cast(int) pTst.apFnc[iIdx]); pTst.apFnc[1](); pTst.apFnc[3](); pTst.apFnc[4](); } /* execution produces: item#0:0x019F3FE0 item#1:0x004020AC item#2:0x019F3FE0 item#3:0x0040215C item#4:0x004021B4 func1 func3 func4 */ /* disassembly shows that wrong code is generated for the 1st and 3rd function pointer assignments: function address is loaded into a register but the destination is written from another one 5: void initTTest(TTest * pTst) 00402010 enter 4,0 00402014 push ebx 00402015 push esi 00402016 mov dword ptr [ebp-4],eax 6: { 7: // pTst.pVtbl = cast(void*) pTst.apFnc.ptr; 8: pTst.apFnc[0] = cast(FnPtr) &pTst.func0; 00402019 mov eax,dword ptr [pTst] 0040201C mov ecx,offset _D8epfuntbl5TTest5func0MFZv (00402054) 00402021 mov edx,dword ptr [pTst] 00402024 mov dword ptr [edx+4],eax 9: pTst.apFnc[1] = cast(FnPtr) &pTst.func1; 00402027 mov ebx,edx 00402029 mov ecx,offset _D8epfuntbl5TTest5func1MFZv (004020ac) 0040202E mov dword ptr [edx+8],ecx 10: pTst.apFnc[2] = cast(FnPtr) &pTst.func2; 00402031 mov eax,edx 00402033 mov ecx,offset _D8epfuntbl5TTest5func2MFZv (00402104) 00402038 mov dword ptr [edx+0Ch],eax 11: pTst.apFnc[3] = cast(FnPtr) &pTst.func3; 0040203B mov esi,edx 0040203D mov ecx,offset _D8epfuntbl5TTest5func3MFZv (0040215c) 00402042 mov dword ptr [edx+10h],ecx 12: pTst.apFnc[4] = cast(FnPtr) &pTst.func4; 00402045 mov ebx,edx 00402047 mov ecx,offset _D8epfuntbl5TTest5func4MFZv (004021b4) 0040204C mov dword ptr [edx+14h],ecx 13: } 0040204F pop esi 00402050 pop ebx 00402051 leave 00402052 ret 00402053 int 3 */ -- | |||
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ReplySeptember 03, 2008 Re: [Issue 2318] New: flaw code generation building a function pointer table | ||||
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 Posted in reply to d-bugmail | If you declare FnPtr as void delegate() then these issues are gone. This works with both DMD 1.034 and DMD 2.018 on Win XP SP3 but using phobos instead of Tango/tangobos.
d-bugmail@puremagic.com Wrote:
> http://d.puremagic.com/issues/show_bug.cgi?id=2318
>
> Summary: flaw code generation building a function pointer table
> Product: D
> Version: 1.034
> Platform: PC
> OS/Version: Windows
> Status: NEW
> Severity: normal
> Priority: P2
> Component: DMD
> AssignedTo: bugzilla@digitalmars.com
> ReportedBy: enzo.petrelli@fastwebnet.it
>
>
> /***************************
> OS: Vista SP1
> Compiler/linker: Digital Mars D Compiler v1.034
> Tango/tangobos Lib: tango-0.99.7-bin-win32-dmd.1.033
> Compiled with: dmd -g -debug epfuntbl.d
>
> Debug version:
> Trying to build a table of 5 function pointers out of
> 5 struct members, 1st and 3rd items are uncorrectly
> asssigned values
>
> Release version:
> A similar but slightly different behaviour is shown.
> Further, an "Access violation" is raised
>
> ***************************/
>
> import std.cstream;
>
> alias void function() FnPtr;
>
> void initTTest(TTest * pTst)
> {
> // pTst.pVtbl = cast(void*) pTst.apFnc.ptr;
> pTst.apFnc[0] = cast(FnPtr) &pTst.func0;
> pTst.apFnc[1] = cast(FnPtr) &pTst.func1;
> pTst.apFnc[2] = cast(FnPtr) &pTst.func2;
> pTst.apFnc[3] = cast(FnPtr) &pTst.func3;
> pTst.apFnc[4] = cast(FnPtr) &pTst.func4;
> }
>
> struct TTest
> {
> void * pVtbl;
> FnPtr[5] apFnc;
>
> void func0()
> {
> dout.writefln("func0");
> }
> void func1()
> {
> dout.writefln("func1");
> }
> void func2()
> {
> dout.writefln("func2");
> }
> void func3()
> {
> dout.writefln("func3");
> }
> void func4()
> {
> dout.writefln("func4");
> }
> }
>
> void main()
> {
> TTest * pTst = new TTest;
> initTTest(pTst);
> for (int iIdx = 0; iIdx < pTst.apFnc.length; ++iIdx)
> dout.writefln("item#%d:0x%08X", iIdx, cast(int)
> pTst.apFnc[iIdx]);
> pTst.apFnc[1]();
> pTst.apFnc[3]();
> pTst.apFnc[4]();
> }
>
> /*
> execution produces:
>
> item#0:0x019F3FE0
> item#1:0x004020AC
> item#2:0x019F3FE0
> item#3:0x0040215C
> item#4:0x004021B4
> func1
> func3
> func4
> */
>
> /*
> disassembly shows that wrong code is generated for the 1st and 3rd
> function pointer assignments:
> function address is loaded into a register but the destination is
> written from another one
>
> 5: void initTTest(TTest * pTst)
> 00402010 enter 4,0
> 00402014 push ebx
> 00402015 push esi
> 00402016 mov dword ptr [ebp-4],eax
> 6: {
> 7: // pTst.pVtbl = cast(void*) pTst.apFnc.ptr;
> 8: pTst.apFnc[0] = cast(FnPtr) &pTst.func0;
> 00402019 mov eax,dword ptr [pTst]
> 0040201C mov ecx,offset _D8epfuntbl5TTest5func0MFZv (00402054)
> 00402021 mov edx,dword ptr [pTst]
> 00402024 mov dword ptr [edx+4],eax
> 9: pTst.apFnc[1] = cast(FnPtr) &pTst.func1;
> 00402027 mov ebx,edx
> 00402029 mov ecx,offset _D8epfuntbl5TTest5func1MFZv (004020ac)
> 0040202E mov dword ptr [edx+8],ecx
> 10: pTst.apFnc[2] = cast(FnPtr) &pTst.func2;
> 00402031 mov eax,edx
> 00402033 mov ecx,offset _D8epfuntbl5TTest5func2MFZv (00402104)
> 00402038 mov dword ptr [edx+0Ch],eax
> 11: pTst.apFnc[3] = cast(FnPtr) &pTst.func3;
> 0040203B mov esi,edx
> 0040203D mov ecx,offset _D8epfuntbl5TTest5func3MFZv (0040215c)
> 00402042 mov dword ptr [edx+10h],ecx
> 12: pTst.apFnc[4] = cast(FnPtr) &pTst.func4;
> 00402045 mov ebx,edx
> 00402047 mov ecx,offset _D8epfuntbl5TTest5func4MFZv (004021b4)
> 0040204C mov dword ptr [edx+14h],ecx
> 13: }
> 0040204F pop esi
> 00402050 pop ebx
> 00402051 leave
> 00402052 ret
> 00402053 int 3
> */
>
>
> --
>
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April 08, 2009 [Issue 2318] flaw code generation building a function pointer table | ||||
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Posted in reply to d-bugmail | http://d.puremagic.com/issues/show_bug.cgi?id=2318 clugdbug@yahoo.com.au changed: What |Removed |Added ---------------------------------------------------------------------------- Severity|normal |critical ------- Comment #1 from clugdbug@yahoo.com.au 2009-04-08 07:42 ------- This also applies to D2.(DMD2.028). -- | |||
February 01, 2010 [Issue 2318] flaw code generation building a function pointer table | ||||
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 Posted in reply to d-bugmail | http://d.puremagic.com/issues/show_bug.cgi?id=2318 Don <clugdbug@yahoo.com.au> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED CC| |clugdbug@yahoo.com.au Resolution| |INVALID --- Comment #2 from Don <clugdbug@yahoo.com.au> 2010-02-01 07:26:10 PST --- This is invalid: the code creates delegates, then casts them to function pointers. To create the desired effect, this line: pTst.apFnc[0] = cast(FnPtr) &pTst.func0; should be changed to: pTst.apFnc[0] = &TTest.func0; -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- | |||
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