On Mon, Dec 21, 2015 at 4:19 PM, Andrew Pinski <pins...@gmail.com> wrote: > On Mon, Dec 21, 2015 at 4:10 PM, Ian Lance Taylor <i...@golang.org> wrote: >> The GNU linker doesn't support a zero-sized global variable that is >> dynamically exported, so gccgo generates those global variables with a >> size of 1 byte. Unfortunately, that means that passing a global >> variable to a function that takes an argument of a zero-sized type >> will actually pass 1 byte, taking up an argument slot, rather than a >> zero-sized argument that should be skipped. This patch fixes the >> problem in the Go frontend -> GCC interface by adding a conversion to >> the real type for any such global variables, and undoing the >> conversion where necessary. Bootstrapped and ran Go testsuite on >> x86_64-pc-linux-gnu. Committed to mainline and gccgo branch. > > VIEW_CONVERT_EXPR on different size types is invalid for GCC's IR. > So this patch cause other issues.
Hmmm, thanks for the pointer. Any suggestions? The constraints are that the variable has to be non-zero sized (or the GNU linker complains) and I can't entirely drop the reference to the variable (or the linker might fail to pull in an object from an archive) and the resulting expression has to be zero-sized (or the function call is miscompiled). ian
