Bug 13939 – IASM shouldn't access global symbol with PIC code

cat > bug.d << CODE void test1() { __gshared int val; asm { mov EAX, val; } } CODE dmd -c -fPIC bug It should be an error to access a global variable in IASM when compiling PIC code.

Like for TLS access to global PIC variables requires a particular instruction sequence and relocation. Particularly for i686 you need to add the GOT offset (there currently no way to get that in IASM though). BUT on amd64 it basically works fine because the compiler rewrites. mov RAX, val; to mov RAX, val@RIP; and also emits the correct relocation. It will already fail for movdqa XMM1, val; see bug 9378.

Commits pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/c9a383cb926580c22a9219619750bc801eb9b159 fix Issue 13939 - IASM shouldn't access global symbol with PIC code https://github.com/D-Programming-Language/dmd/commit/756cda4c5a73ac35c7f48faae20de73493d210a4 Merge pull request #4260 from 9rnsr/fix_iasm Issue 13938 & 13939 - Disallow non-trivial variable accesses in iasm

Commits pushed to 2.067 at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/c9a383cb926580c22a9219619750bc801eb9b159 fix Issue 13939 - IASM shouldn't access global symbol with PIC code https://github.com/D-Programming-Language/dmd/commit/756cda4c5a73ac35c7f48faae20de73493d210a4 Merge pull request #4260 from 9rnsr/fix_iasm