PowerPCs have static instruction lengths, so writing an "in-between" brl detection is quite simple on this architecture. You are welcome to write something like this for any other platform, but if a compile doesn't trigger build errors on PowerPC, it shouldn't on other platforms either, as PowerPC has quite advanced branch instructions.
This patch is not mandatory, makes debugging a lot easier though.
Index: qemu-snapshot-2008-01-15_05/dyngen.c =================================================================== --- qemu-snapshot-2008-01-15_05.orig/dyngen.c +++ qemu-snapshot-2008-01-15_05/dyngen.c @@ -1488,6 +1488,16 @@ void gen_code(const char *name, host_ulo if (get32((uint32_t *)p) != 0x4e800020) error("blr expected at the end of %s", name); copy_size = p - p_start; + +/* blr check for inline returns */ + + if(strstart(name, "op_", NULL) && !strstart(name, "op_exit", NULL)) { + for(p=p_start; p < p_end - 4; p+=4) { + if ((get32((uint32_t *)p) & 0xfc00fff0) == 0x4c000020) { + error("Inline blr detected in %s. Please append FORCE_RET to the function.", name); + } + } + } } #elif defined(HOST_S390) {