On Wed, Sep 11, 2013 at 2:53 AM, Andrew Haley <aph@xxxxxxxxxx> wrote: > On 09/10/2013 05:35 PM, Dave Allured - NOAA Affiliate wrote: >>> On 09/10/2013 01:21 AM, Dave Allured - NOAA Affiliate wrote: >>>> Hello, I am trying to create a dynamic library for >>>> x86_64-apple-darwin12 (Mac OS) with gcc 4.8.1. My source code >>>> includes some simple functions that I think are being identified as >>>> leaf functions. This works fine when compiling to a static library. >>>> >>>> However, when compiling to dynamic library (-dynamiclib etc.), seg >>>> fault results immediately on call from one of these leaf-like >>>> functions to another. GDB tells me that the stack becomes misaligned >>>> in the calling function, and the actual seg fault happens within a >>>> dynamic loader stub function. The simplified message from GDB is: >>>> >>>> misaligned_stack_error_entering_dyld_stub_binder >>>> >> On Tue, Sep 10, 2013 at 3:42 AM, Andrew Haley <aph@xxxxxxxxxx> wrote: >>> What is the faulting instruction? >>> >>> x/i $pc >> >> movdqa, an SSE instruction that requires 16-byte alignment. This is >> about a dozen instructions within the dynamic loader. > > OK, that makes sense. Now, a leaf function cannot call a function: so, > what is the assembly code of the "leaf-like" function makinf th ecall? > > Andrew. My bad, I misunderstood the meaning of leaf function and lept to assumptions. Now I see that my problem probably has nothing to do with leaf functions. Thank you for correcting my novice mistake. I would like to make a reduced test case and post it under a new title that is hopefully not misleading. --Dave
