On Thu, 15 Jun 2017, Wilco Dijkstra wrote: > Richard Earnshaw wrote: > > No it's not. The optimizer doesn't create totally random bases. If the > > code + data is less than 1M in size, then any offsets it does create > > will fit within the size of the relocations selected by the compiler. > > No that's completely false. There is no way you can guarantee that without > my patch. My patch is precisely there to ensure we only allow offsets that > guarantee linking succeeds if all code and data fits in 1M or 4GB.
For example, given (array + (i - INT_MAX)), it's quite possible the compiler could create a relocation for array - INT_MAX, and the original expression is perfectly OK if i == INT_MAX even though array - INT_MAX is far out of range. (And array - INT_MAX as a C expression is only undefined at runtime, not at compile time if it's in code that is never executed.) -- Joseph S. Myers jos...@codesourcery.com
