diff options
| author | Bernhard Schommer <bschommer@users.noreply.github.com> | 2018-09-12 14:32:01 +0200 |
|---|---|---|
| committer | Xavier Leroy <xavierleroy@users.noreply.github.com> | 2018-09-12 14:32:01 +0200 |
| commit | 591073be98300e1c07527af45c7c4ce8dff5bc39 (patch) | |
| tree | 1f5143b8405b4d33a6133a7210839dab1e6eaad6 /arm/Asmexpand.ml | |
| parent | 25ba7367a0d9391a4bea2d7685b8cfe8e304e2f8 (diff) | |
| download | compcert-kvx-591073be98300e1c07527af45c7c4ce8dff5bc39.tar.gz compcert-kvx-591073be98300e1c07527af45c7c4ce8dff5bc39.zip | |
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
Diffstat (limited to 'arm/Asmexpand.ml')
| -rw-r--r-- | arm/Asmexpand.ml | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/arm/Asmexpand.ml b/arm/Asmexpand.ml index 7c18be6b..d9424d11 100644 --- a/arm/Asmexpand.ml +++ b/arm/Asmexpand.ml @@ -404,6 +404,8 @@ let expand_builtin_inline name args res = (* Vararg stuff *) | "__builtin_va_start", [BA(IR a)], _ -> expand_builtin_va_start a + | "__builtin_nop", [], _ -> + emit Pnop (* Catch-all *) | _ -> raise (Error ("unrecognized builtin " ^ name)) @@ -665,10 +667,7 @@ let expand_function id fn = try set_current_function fn; fixup_arguments Incoming fn.fn_sig; - if !Clflags.option_g then - expand_debug id 13 preg_to_dwarf expand_instruction fn.fn_code - else - List.iter expand_instruction fn.fn_code; + expand id 13 preg_to_dwarf expand_instruction fn.fn_code; let fn = get_current_function () in let fn = Constantexpand.expand_constants fn in Errors.OK fn |