> Is there a good way of creating an assembler comments directly from RTL? > > I want to be able to add debugging/explanation strings to assembler > listing (GAS). Unfortunately I want to do this from RTL prologue and > epilogue (and thus avoid using TARGET_ASM_FUNCTION_EPILOGUE - where > it would be easy!)
You might get part of it through the TARGET_START_FUNCTION hook. You can also define insns that use unspec or unspec_volatile, which are generated as part of your prologue/epilogue, that use a C function to emit themselves as assembler. The C function can return a properly formatted pattern that produces the comments you want in the final asm file. You could also hook ASM_OUTPUT_OPCODE to turn "keyword" opcodes from those types of insns into full comments as needed.
