Trevor Scroggins <trevor.scrogg...@gmail.com> writes: > Hello, all. I'm attempting to port GCC 4.4.0 to a new m68k target. The > target begins execution in the first byte of the first text section. > Adding '#define CONSTANT_POOL_BEFORE_FUNCTION 0' in my target's tm.h > seems like the simplest way to avoid execution of read-only data; > however, defining the constant has no effect on compilation. (Note, > custom or missing startup code is common, so I can't work around it > there.) > > The only references to CONSTANT_POOL_BEFORE_FUNCTION are in varasm.c, > and the only target current using the definition is pdp11--not exactly > current. Is CONSTANT_POOL_BEFORE_FUNCTION still being used, or have I > hit upon a section of dead code? Is there a simple way to relocate > read-only data to the end of a function without writing a > target-specific reorg routine? Jumping over the data in a prologue > might be an easy, quick and dirty solution, but the target is a > memory-constrained system, and that seems wasteful.
Setting CONSTANT_POOL_BEFORE_FUNCTION to 0 ought to work to emit the constant pool after the function. However, to be clear, it only affects the constant pool which holds constants which are not LEGITIMATE_CONSTANT_P. This is normally things like 32-bit constants which RISC architectures can not handle in a single instruction. The m68k is a flexible architecture and can handle 32-bit constants just fine without using a constant pool. You didn't really describe what you are seeing; what makes you think that the constant pool is the problem? Ian
