Consider the following code:
extern "C" void exceptions() {
asm ("\t" "1:" "\n"
"\t" ".seh_handler __C_specific_handler, @except" "\n"
"\t" ".seh_handlerdata" "\n"
"\t" ".long 1" "\n"
"\t" ".rva 1b, 2f, 3f, 4f" "\n"
"\t" ".seh_code");
{
// std::printf("Guarded\n");
RaiseException(EXCEPTION_BREAKPOINT, 0, 0, nullptr);
}
asm ("nop" "\n"
"\t" "2: nop" "\n"
"\t" "jmp 5f" "\n"
"\t" "3:" "\n"
"\t" "push rbp" "\n"
"\t" "mov rbp, rsp" "\n");
{
const volatile long filter = EXCEPTION_EXECUTE_HANDLER;
}
asm ("mov eax, DWORD PTR -8[rbp]" "\n"
"\t" "pop rbp" "\n"
"\t" "ret" "\n"
"\t" "4:");
{
std::printf("Exception\n");
}
asm ("5:");
std::printf("Intermission\n");
asm ("\t" "1:" "\n"
"\t" ".seh_handler __C_specific_handler, @except" "\n"
"\t" ".seh_handlerdata" "\n"
"\t" ".long 2" "\n"
"\t" ".rva 1b, 2f, 3f, 4f" "\n"
"\t" ".seh_code");
{
// std::printf("Guarded\n");
RaiseException(EXCEPTION_BREAKPOINT, 0, 0, nullptr);
}
asm ("nop" "\n"
"\t" "2: nop" "\n"
"\t" "jmp 5f" "\n"
"\t" "3:" "\n"
"\t" "push rbp" "\n"
"\t" "mov rbp, rsp" "\n");
{
const volatile long filter = EXCEPTION_EXECUTE_HANDLER;
}
asm ("mov eax, DWORD PTR -8[rbp]" "\n"
"\t" "pop rbp" "\n"
"\t" "ret" "\n"
"\t" "4:");
{
std::printf("Exception\n");
}
asm ("5:");
}
The expected output would be:
Exception
Intermission
Exception
But the actual output is:
Exception
Intermission
Given that a function only has one __C_specific_handler, and multiple
Structured Exception try blocks are handled with multiple scope tables, or
.seh_handlerdata as gcc calls them, the fault must lie with
.seh_handlerdata. Is there only allowed to be one .seh_handlerdata emitting
.xdata information about the try and except blocks per function? Because if
so, this should be considered a defect and fixed either upstream or locally
within MinGW, because Windows can and does use multiple scope tables for
each try block per function all the time
best regards,
Julian
_______________________________________________
Mingw-w64-public mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/mingw-w64-public
