Bug 7750 – while(true) loop with try/catch block causes segfault

I ran into a segfault when using a try/catch block inside a while(true) loop when there are other statements after the try/catch block. I reduced it down to this consistent segfault: import std.stdio; void main() { while (true) { try { throw new Exception("ah"); } catch (Exception e) { } writeln("remove this line and it won't segfault"); } } This segfaults in the first iteration on DMD 2.058 on OS X 10.7.3. It segfaults with both -m32 and -m64. Stacktrace: 0 libdyld.dylib 0x00007fff8f3436cd misaligned_stack_error_entering_dyld_stub_binder + 0 1 ??? 0x000000010f535030 0 + 4552085552 2 bug1.d.DC445724916B27653F5E50703AE848DF 0x000000010f51f133 _Dmain + 103 3 bug1.d.DC445724916B27653F5E50703AE848DF 0x000000010f52f8dd D2rt6dmain24mainUiPPaZi7runMainMFZv + 29 4 bug1.d.DC445724916B27653F5E50703AE848DF 0x000000010f52f28d D2rt6dmain24mainUiPPaZi7tryExecMFMDFZvZv + 45 5 bug1.d.DC445724916B27653F5E50703AE848DF 0x000000010f52f92f D2rt6dmain24mainUiPPaZi6runAllMFZv + 63 6 bug1.d.DC445724916B27653F5E50703AE848DF 0x000000010f52f28d D2rt6dmain24mainUiPPaZi7tryExecMFMDFZvZv + 45 7 bug1.d.DC445724916B27653F5E50703AE848DF 0x000000010f52f210 main + 232 8 bug1.d.DC445724916B27653F5E50703AE848DF 0x000000010f51f0c4 start + 52 Removing the writeln, or changing it to a non-infinite loop like int x;while(++x<3) will avoid the segfault, so it seems likely DMD is making a bad assumption about the loop related to it being infinite.

I can't seem to reproduce this problem with the latest git dmd (2.059 candidate) on Linux AMD64. Could it be a Mac-specific problem?

(In reply to comment #1) > I can't seem to reproduce this problem with the latest git dmd (2.059 > candidate) on Linux AMD64. Could it be a Mac-specific problem? Looks like it, based on the first location in the backtrace: misaligned_stack_error_entering_dyld_stub_binder The stack isn't getting aligned properly before the call to writeln.

Probably related to bug 1115.

Commit pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/1fba8be9f381c01315d01d74b52ce616c5afc745 fix Issue 7750 - while(true) loop with try/catch block causes segfault

Commit pushed to dmd-1.x at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/99c11c44985493a1e9974bad8510cf377cd208a5 fix Issue 7750 - while(true) loop with try/catch block causes segfault