RISC-V port and assorted changes

This commits adds code generation for the RISC-V architecture, both in 32- and 64-bit modes.

The generated code was lightly tested using the simulator and cross-binutils from https://riscv.org/software-tools/

This port required the following additional changes:

- Integers: More properties about shrx

- SelectOp: now provides smart constructors for mulhs and mulhu

- SelectDiv, 32-bit integer division and modulus: implement constant propagation, use the new smart constructors mulhs and mulhu.

- Runtime library: if no asm implementation is provided, run the reference C implementation through CompCert.  Since CompCert rejects the definitions of names of special functions such as __i64_shl, the reference implementation now uses "i64_" names, e.g. "i64_shl", and a renaming "i64_ -> __i64_" is performed over the generated assembly file, before assembling and building the runtime library.

- test/: add SIMU make variable to run tests through a simulator

- test/regression/alignas.c: make sure _Alignas and _Alignof are not #define'd by C headers

commit da14495c01cf4f66a928c2feff5c53f09bde837f
Author: Xavier Leroy <xavier.leroy@inria.fr>
Date:   Thu Apr 13 17:36:10 2017 +0200

    RISC-V port, continued

    Now working on Asmgen.

commit 36f36eb3a5abfbb8805960443d087b6a83e86005
Author: Xavier Leroy <xavier.leroy@inria.fr>
Date:   Wed Apr 12 17:26:39 2017 +0200

    RISC-V port, first steps

    This port is based on Prashanth Mundkur's experimental RV32 port and brings it up to date with CompCert, and adds 64-bit support (RV64).  Work in progress.

1 files changed, 166 insertions, 0 deletions

diff --git a/riscV/PrintOp.ml b/riscV/PrintOp.ml
new file mode 100644
index 00000000..9ec474b3
--- /dev/null
+++ b/riscV/PrintOp.ml
@@ -0,0 +1,166 @@
+(* *********************************************************************)
+(*                                                                     *)
+(*              The Compcert verified compiler                         *)
+(*                                                                     *)
+(*          Xavier Leroy, INRIA Paris-Rocquencourt                     *)
+(*           Prashanth Mundkur, SRI International                      *)
+(*                                                                     *)
+(*  Copyright Institut National de Recherche en Informatique et en     *)
+(*  Automatique.  All rights reserved.  This file is distributed       *)
+(*  under the terms of the INRIA Non-Commercial License Agreement.     *)
+(*                                                                     *)
+(*  The contributions by Prashanth Mundkur are reused and adapted      *)
+(*  under the terms of a Contributor License Agreement between         *)
+(*  SRI International and INRIA.                                       *)
+(*                                                                     *)
+(* *********************************************************************)
+
+(** Pretty-printing of operators, conditions, addressing modes *)
+
+open Printf
+open Camlcoq
+open Integers
+open Op
+
+let comparison_name = function
+  | Ceq -> "=="
+  | Cne -> "!="
+  | Clt -> "<"
+  | Cle -> "<="
+  | Cgt -> ">"
+  | Cge -> ">="
+
+let print_condition reg pp = function
+  | (Ccomp c, [r1;r2]) ->
+      fprintf pp "%a %ss %a" reg r1 (comparison_name c) reg r2
+  | (Ccompu c, [r1;r2]) ->
+      fprintf pp "%a %su %a" reg r1 (comparison_name c) reg r2
+  | (Ccompimm(c, n), [r1]) ->
+      fprintf pp "%a %ss %ld" reg r1 (comparison_name c) (camlint_of_coqint n)
+  | (Ccompuimm(c, n), [r1]) ->
+      fprintf pp "%a %su %ld" reg r1 (comparison_name c) (camlint_of_coqint n)
+  | (Ccompf c, [r1;r2]) ->
+      fprintf pp "%a %sf %a" reg r1 (comparison_name c) reg r2
+  | (Ccompl c, [r1;r2]) ->
+      fprintf pp "%a %sls %a" reg r1 (comparison_name c) reg r2
+  | (Ccomplu c, [r1;r2]) ->
+      fprintf pp "%a %slu %a" reg r1 (comparison_name c) reg r2
+  | (Ccomplimm(c, n), [r1]) ->
+      fprintf pp "%a %sls %Ld" reg r1 (comparison_name c) (camlint64_of_coqint n)
+  | (Ccompluimm(c, n), [r1]) ->
+      fprintf pp "%a %slu %Lu" reg r1 (comparison_name c) (camlint64_of_coqint n)
+  | (Cnotcompf c, [r1;r2]) ->
+      fprintf pp "%a not(%sf) %a" reg r1 (comparison_name c) reg r2
+  | (Ccompfs c, [r1;r2]) ->
+      fprintf pp "%a %sfs %a" reg r1 (comparison_name c) reg r2
+  | (Cnotcompfs c, [r1;r2]) ->
+      fprintf pp "%a not(%sfs) %a" reg r1 (comparison_name c) reg r2
+  | _ ->
+      fprintf pp "<bad condition>"
+
+let print_operation reg pp = function
+  | Omove, [r1] -> reg pp r1
+  | Ointconst n, [] -> fprintf pp "%ld" (camlint_of_coqint n)
+  | Olongconst n, [] -> fprintf pp "%LdL" (camlint64_of_coqint n)
+  | Ofloatconst n, [] -> fprintf pp "%F" (camlfloat_of_coqfloat n)
+  | Osingleconst n, [] -> fprintf pp "%Ff" (camlfloat_of_coqfloat32 n)
+  | Oaddrsymbol(id, ofs), [] ->
+      fprintf pp "\"%s\" + %Ld" (extern_atom id) (camlint64_of_ptrofs ofs)
+  | Oaddrstack ofs, [] ->
+      fprintf pp "stack(%Ld)" (camlint64_of_ptrofs ofs)
+  | Ocast8signed, [r1] -> fprintf pp "int8signed(%a)" reg r1
+  | Ocast16signed, [r1] -> fprintf pp "int16signed(%a)" reg r1
+  | Oadd, [r1;r2] -> fprintf pp "%a + %a" reg r1 reg r2
+  | Oaddimm n, [r1] -> fprintf pp "%a + %ld" reg r1 (camlint_of_coqint n)
+  | Oneg, [r1] -> fprintf pp "-(%a)" reg r1
+  | Osub, [r1;r2] -> fprintf pp "%a - %a" reg r1 reg r2
+  | Omul, [r1;r2] -> fprintf pp "%a * %a" reg r1 reg r2
+  | Omulhs, [r1;r2] -> fprintf pp "%a *hs %a" reg r1 reg r2
+  | Omulhu, [r1;r2] -> fprintf pp "%a *hu %a" reg r1 reg r2
+  | Odiv, [r1;r2] -> fprintf pp "%a /s %a" reg r1 reg r2
+  | Odivu, [r1;r2] -> fprintf pp "%a /u %a" reg r1 reg r2
+  | Omod, [r1;r2] -> fprintf pp "%a %%s %a" reg r1 reg r2
+  | Omodu, [r1;r2] -> fprintf pp "%a %%u %a" reg r1 reg r2
+  | Oand, [r1;r2] -> fprintf pp "%a & %a" reg r1 reg r2
+  | Oandimm n, [r1] -> fprintf pp "%a & %ld" reg r1 (camlint_of_coqint n)
+  | Oor, [r1;r2] -> fprintf pp "%a | %a" reg r1 reg r2
+  | Oorimm n, [r1] ->  fprintf pp "%a | %ld" reg r1 (camlint_of_coqint n)
+  | Oxor, [r1;r2] -> fprintf pp "%a ^ %a" reg r1 reg r2
+  | Oxorimm n, [r1] -> fprintf pp "%a ^ %ld" reg r1 (camlint_of_coqint n)
+  | Oshl, [r1;r2] -> fprintf pp "%a << %a" reg r1 reg r2
+  | Oshlimm n, [r1] -> fprintf pp "%a << %ld" reg r1 (camlint_of_coqint n)
+  | Oshr, [r1;r2] -> fprintf pp "%a >>s %a" reg r1 reg r2
+  | Oshrimm n, [r1] -> fprintf pp "%a >>s %ld" reg r1 (camlint_of_coqint n)
+  | Oshru, [r1;r2] -> fprintf pp "%a >>u %a" reg r1 reg r2
+  | Oshruimm n, [r1] -> fprintf pp "%a >>u %ld" reg r1 (camlint_of_coqint n)
+  | Oshrximm n, [r1] -> fprintf pp "%a >>x %ld" reg r1 (camlint_of_coqint n)
+
+  | Omakelong, [r1;r2] -> fprintf pp "makelong(%a,%a)" reg r1 reg r2
+  | Olowlong, [r1] -> fprintf pp "lowlong(%a)" reg r1
+  | Ohighlong, [r1] -> fprintf pp "highlong(%a)" reg r1
+  | Ocast32signed, [r1] -> fprintf pp "long32signed(%a)" reg r1
+  | Ocast32unsigned, [r1] -> fprintf pp "long32unsigned(%a)" reg r1
+  | Oaddl, [r1;r2] -> fprintf pp "%a +l %a" reg r1 reg r2
+  | Oaddlimm n, [r1] -> fprintf pp "%a +l %Ld" reg r1 (camlint64_of_coqint n)
+  | Onegl, [r1] -> fprintf pp "-l (%a)" reg r1
+  | Osubl, [r1;r2] -> fprintf pp "%a -l %a" reg r1 reg r2
+  | Omull, [r1;r2] -> fprintf pp "%a *l %a" reg r1 reg r2
+  | Omullhs, [r1;r2] -> fprintf pp "%a *lhs %a" reg r1 reg r2
+  | Omullhu, [r1;r2] -> fprintf pp "%a *lhu %a" reg r1 reg r2
+  | Odivl, [r1;r2] -> fprintf pp "%a /ls %a" reg r1 reg r2
+  | Odivlu, [r1;r2] -> fprintf pp "%a /lu %a" reg r1 reg r2
+  | Omodl, [r1;r2] -> fprintf pp "%a %%ls %a" reg r1 reg r2
+  | Omodlu, [r1;r2] -> fprintf pp "%a %%lu %a" reg r1 reg r2
+  | Oandl, [r1;r2] -> fprintf pp "%a &l %a" reg r1 reg r2
+  | Oandlimm n, [r1] -> fprintf pp "%a &l %Ld" reg r1 (camlint64_of_coqint n)
+  | Oorl, [r1;r2] -> fprintf pp "%a |l %a" reg r1 reg r2
+  | Oorlimm n, [r1] ->  fprintf pp "%a |l %Ld" reg r1 (camlint64_of_coqint n)
+  | Oxorl, [r1;r2] -> fprintf pp "%a ^l %a" reg r1 reg r2
+  | Oxorlimm n, [r1] -> fprintf pp "%a ^l %Ld" reg r1 (camlint64_of_coqint n)
+  | Oshll, [r1;r2] -> fprintf pp "%a <<l %a" reg r1 reg r2
+  | Oshllimm n, [r1] -> fprintf pp "%a <<l %Ld" reg r1 (camlint64_of_coqint n)
+  | Oshrl, [r1;r2] -> fprintf pp "%a >>ls %a" reg r1 reg r2
+  | Oshrlimm n, [r1] -> fprintf pp "%a >>ls %ld" reg r1 (camlint_of_coqint n)
+  | Oshrlu, [r1;r2] -> fprintf pp "%a >>lu %a" reg r1 reg r2
+  | Oshrluimm n, [r1] -> fprintf pp "%a >>lu %ld" reg r1 (camlint_of_coqint n)
+  | Oshrxlimm n, [r1] -> fprintf pp "%a >>lx %ld" reg r1 (camlint_of_coqint n)
+
+  | Onegf, [r1] -> fprintf pp "negf(%a)" reg r1
+  | Oabsf, [r1] -> fprintf pp "absf(%a)" reg r1
+  | Oaddf, [r1;r2] -> fprintf pp "%a +f %a" reg r1 reg r2
+  | Osubf, [r1;r2] -> fprintf pp "%a -f %a" reg r1 reg r2
+  | Omulf, [r1;r2] -> fprintf pp "%a *f %a" reg r1 reg r2
+  | Odivf, [r1;r2] -> fprintf pp "%a /f %a" reg r1 reg r2
+  | Onegfs, [r1] -> fprintf pp "negfs(%a)" reg r1
+  | Oabsfs, [r1] -> fprintf pp "absfs(%a)" reg r1
+  | Oaddfs, [r1;r2] -> fprintf pp "%a +fs %a" reg r1 reg r2
+  | Osubfs, [r1;r2] -> fprintf pp "%a -fs %a" reg r1 reg r2
+  | Omulfs, [r1;r2] -> fprintf pp "%a *fs %a" reg r1 reg r2
+  | Odivfs, [r1;r2] -> fprintf pp "%a /fs %a" reg r1 reg r2
+  | Osingleoffloat, [r1] -> fprintf pp "singleoffloat(%a)" reg r1
+  | Ofloatofsingle, [r1] -> fprintf pp "floatofsingle(%a)" reg r1
+  | Ointoffloat, [r1] -> fprintf pp "intoffloat(%a)" reg r1
+  | Ointuoffloat, [r1] -> fprintf pp "intuoffloat(%a)" reg r1
+  | Ofloatofint, [r1] -> fprintf pp "floatofint(%a)" reg r1
+  | Ofloatofintu, [r1] -> fprintf pp "floatofintu(%a)" reg r1
+  | Olongoffloat, [r1] -> fprintf pp "longoffloat(%a)" reg r1
+  | Olonguoffloat, [r1] -> fprintf pp "longuoffloat(%a)" reg r1
+  | Ofloatoflong, [r1] -> fprintf pp "floatoflong(%a)" reg r1
+  | Ofloatoflongu, [r1] -> fprintf pp "floatoflongu(%a)" reg r1
+  | Ointofsingle, [r1] -> fprintf pp "intofsingle(%a)" reg r1
+  | Ointuofsingle, [r1] -> fprintf pp "intuofsingle(%a)" reg r1
+  | Osingleofint, [r1] -> fprintf pp "singleofint(%a)" reg r1
+  | Osingleofintu, [r1] -> fprintf pp "singleofintu(%a)" reg r1
+  | Olongofsingle, [r1] -> fprintf pp "longofsingle(%a)" reg r1
+  | Olonguofsingle, [r1] -> fprintf pp "longuofsingle(%a)" reg r1
+  | Osingleoflong, [r1] -> fprintf pp "singleoflong(%a)" reg r1
+  | Osingleoflongu, [r1] -> fprintf pp "singleoflongu(%a)" reg r1
+  | Ocmp c, args -> print_condition reg pp (c, args)
+  | _ -> fprintf pp "<bad operator>"
+
+let print_addressing reg pp = function
+  | Aindexed n, [r1] -> fprintf pp "%a + %Ld" reg r1 (camlint64_of_ptrofs n)
+  | Aglobal(id, ofs), [] ->
+      fprintf pp "\"%s\" + %Ld" (extern_atom id) (camlint64_of_ptrofs ofs)
+  | Ainstack ofs, [] -> fprintf pp "stack(%Ld)" (camlint64_of_ptrofs ofs)
+  | _ -> fprintf pp "<bad addressing>"