From 591073be98300e1c07527af45c7c4ce8dff5bc39 Mon Sep 17 00:00:00 2001 From: Bernhard Schommer Date: Wed, 12 Sep 2018 14:32:01 +0200 Subject: Generate a nop instruction after some ais annotations (#137) * Generate a nop instruction after ais annotations. In order to prevent the merging of ais annotations with following Labels a nop instruction is inserted, but only if the annotation is followed immediately by a label. The insertion of nop instructions is performed during the expansion of builtin and pseudo assembler instructions and is processor independent, by inserting a __builtin_nop built-in. * Add Pnop instruction to ARM, RISC-V, and x86 ARM as well as RISC-V don't have nop instructions that can be easily encoded by for example add with zero instructions. For x86 we used to use `mov X0, X0` for nop but this may not be as efficient as the true nop instruction. * Implement __builtin_nop on all supported target architectures. This builtin is not yet made available on the C side for all architectures. Bug 24067 --- riscV/Asmexpand.ml | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) (limited to 'riscV/Asmexpand.ml') diff --git a/riscV/Asmexpand.ml b/riscV/Asmexpand.ml index 0a7f8a8a..3e734747 100644 --- a/riscV/Asmexpand.ml +++ b/riscV/Asmexpand.ml @@ -468,7 +468,8 @@ let expand_builtin_inline name args res = (fun rl -> emit (Pmulw (rl, X a, X b)); emit (Pmulhuw (rh, X a, X b))) - + | "__builtin_nop", [], _ -> + emit Pnop (* Catch-all *) | _ -> raise (Error ("unrecognized builtin " ^ name)) @@ -598,10 +599,7 @@ let preg_to_dwarf = function let expand_function id fn = try set_current_function fn; - if !Clflags.option_g then - expand_debug id (* sp= *) 2 preg_to_dwarf expand_instruction fn.fn_code - else - List.iter expand_instruction fn.fn_code; + expand id (* sp= *) 2 preg_to_dwarf expand_instruction fn.fn_code; Errors.OK (get_current_function ()) with Error s -> Errors.Error (Errors.msg (coqstring_of_camlstring s)) -- cgit