use Makefile to "cross"-build xen and freestanding

As discussed in mirage/mirage-xen#23, using dune's C compilation support leads
to unexpected CFLAGS, especially -fPIC and -fno-strict-aliasing in our setup.

To regain control of CFLAGS, instead use a Makefile. There's no need for the
OCaml mirage-crypto.freestanding / mirage-crypto.xen sublibraries anymore.
Failure of compilation are allowed if the respective opam packages
(mirage-xen-posix, ocaml-freestanding) are not installed.

For a successful cold `dune build @install` run, (alias install) is added to
the (copy-files# ..) stanze in xen/dune and freestanding/dune.

The libmirage_crypto_{xen,freestanding}_stubs.a are installed directly in the
lib/mirage-crypto/ directory.

.travis.yml

@@ -14,7 +14,7 @@ jobs:
   include:
   - name: OCaml 4.08 with mirage-xen
     arch: amd64
-    env: OCAML_VERSION=4.08 DEPOPTS="zarith-xen mirage-xen-posix"
+    env: OCAML_VERSION=4.08 DEPOPTS="zarith-xen mirage-xen-posix mirage-xen-ocaml"
   - name: OCaml 4.10 on arm64
     arch: arm64
     env: OCAML_VERSION=4.10

META.mirage-crypto.template

@@ -1,4 +1,4 @@
 # DUNE_GEN
 
-xen_linkopts = "-l:xen/libmirage_crypto_xen_stubs.a"
-freestanding_linkopts = "-l:freestanding/libmirage_crypto_freestanding_stubs.a"
+xen_linkopts = "-l:libmirage_crypto_xen_stubs.a"
+freestanding_linkopts = "-l:libmirage_crypto_freestanding_stubs.a"

dune-project

@@ -1,2 +1,2 @@
-(lang dune 2.6)
+(lang dune 2.7)
 (name mirage-crypto)

freestanding/Makefile

@@ -0,0 +1,27 @@
+PKG_CONFIG_PATH := $(shell opam config var prefix)/lib/pkgconfig
+
+EXISTS := $(shell PKG_CONFIG_PATH=$(PKG_CONFIG_PATH) pkg-config --exists ocaml-freestanding; echo $$?)
+
+.PHONY: all clean
+all: libmirage_crypto_freestanding_stubs.a
+
+ifeq ($(EXISTS), 1)
+libmirage_crypto_freestanding_stubs.a:
+	touch $@
+else
+CC ?= cc
+FREESTANDING_CFLAGS := $(shell PKG_CONFIG_PATH=$(PKG_CONFIG_PATH) pkg-config --cflags ocaml-freestanding)
+MIRAGE_CRYPTO_CFLAGS := $(shell sed 's/^(\(.*\))$$/\1/' ../src/cflags.sexp | tr -d '"')
+CFLAGS := $(MIRAGE_CRYPTO_CFLAGS) $(FREESTANDING_CFLAGS)
+
+OBJS=detect_cpu_features.o misc.o misc_sse.o hash_stubs.o md5.o sha1.o \
+  sha256.o sha512.o aes_generic.o aes_aesni.o des_generic.o chacha.o \
+  poly1305-donna.o ghash_pclmul.o ghash_generic.o ghash_ctmul.o \
+  entropy_cpu_stubs.o
+
+libmirage_crypto_freestanding_stubs.a: $(OBJS)
+	$(AR) r $@ $^
+endif
+
+clean:
+	$(RM) $(OBJS) libmirage_crypto_freestanding_stubs.a

freestanding/dune

@@ -1,21 +1,16 @@
-(copy_files# ../src/native/*)
-
-(library
- (name mirage_crypto_freestanding)
- (public_name mirage-crypto.freestanding)
- (optional)
- (libraries ocaml-freestanding)
- (foreign_stubs
-  (language c)
-  (flags
-   (:standard)
-   (:include ../src/cflags.sexp)
-   (:include cflags-freestanding.sexp))
-  (names detect_cpu_features misc misc_sse hash_stubs md5 sha1 sha256 sha512
-    aes_generic aes_aesni des_generic chacha poly1305-donna ghash_pclmul
-    ghash_generic ghash_ctmul entropy_cpu_stubs)))
+(copy_files#
+ (alias install)
+ (files ../src/native/*))
 
 (rule
- (with-stdout-to
-  cflags-freestanding.sexp
-  (run ./cflags.sh)))
+ (deps ../src/cflags.sexp Makefile)
+ (targets libmirage_crypto_freestanding_stubs.a)
+ (action
+  (no-infer
+   (progn
+    (run %{make})))))
+
+(install
+ (package mirage-crypto)
+ (section lib)
+ (files libmirage_crypto_freestanding_stubs.a))

mirage-crypto-pk.opam

@@ -15,7 +15,7 @@ build: [ ["dune" "subst"] {pinned}
 depends: [
   "conf-gmp-powm-sec" {build}
   "ocaml" {>= "4.08.0"}
-  "dune" {>= "2.6"}
+  "dune" {>= "2.7"}
   "ounit" {with-test}
   "randomconv" {with-test & >= "0.1.3"}
   "cstruct" {>="3.2.0"}

mirage-crypto-rng-mirage.opam

@@ -14,7 +14,7 @@ build: [ ["dune" "subst"] {pinned}
 
 depends: [
   "ocaml" {>= "4.08.0"}
-  "dune" {>= "2.6"}
+  "dune" {>= "2.7"}
   "mirage-crypto-rng" {=version}
   "duration"
   "cstruct" {>= "4.0.0"}

mirage-crypto-rng.opam

@@ -14,7 +14,7 @@ build: [ ["dune" "subst"] {pinned}
 
 depends: [
   "ocaml" {>= "4.08.0"}
-  "dune" {>= "2.6"}
+  "dune" {>= "2.7"}
   "dune-configurator" {>= "2.0.0"}
   "duration"
   "cstruct" {>= "4.0.0"}

mirage-crypto.opam

@@ -15,14 +15,14 @@ build: [ ["dune" "subst"] {pinned}
 depends: [
   "conf-pkg-config" {build}
   "ocaml" {>= "4.08.0"}
-  "dune" {>= "2.6"}
+  "dune" {>= "2.7"}
   "dune-configurator" {>= "2.0.0"}
   "ounit" {with-test}
   "cstruct" {>="3.2.0"}
   "eqaf" {>= "0.7"}
 ]
 depopts: [
-  "mirage-xen-posix"
+  "mirage-xen-posix" "mirage-xen-ocaml"
   "ocaml-freestanding"
 ]
 conflicts: [

xen/Makefile

@@ -0,0 +1,27 @@
+PKG_CONFIG_PATH := $(shell opam config var prefix)/lib/pkgconfig
+
+EXISTS := $(shell PKG_CONFIG_PATH=$(PKG_CONFIG_PATH) pkg-config --exists mirage-xen-posix,mirage-xen-ocaml; echo $$?)
+
+.PHONY: all clean
+all: libmirage_crypto_xen_stubs.a
+
+ifeq ($(EXISTS), 1)
+libmirage_crypto_xen_stubs.a:
+	touch $@
+else
+CC ?= cc
+XEN_CFLAGS := $(shell PKG_CONFIG_PATH=$(PKG_CONFIG_PATH) pkg-config --cflags mirage-xen-posix,mirage-xen-ocaml)
+MIRAGE_CRYPTO_CFLAGS := $(shell sed 's/^(\(.*\))$$/\1/' ../src/cflags.sexp | tr -d '"')
+CFLAGS := $(MIRAGE_CRYPTO_CFLAGS) $(XEN_CFLAGS)
+
+OBJS=detect_cpu_features.o misc.o misc_sse.o hash_stubs.o md5.o sha1.o \
+  sha256.o sha512.o aes_generic.o aes_aesni.o des_generic.o chacha.o \
+  poly1305-donna.o ghash_pclmul.o ghash_generic.o ghash_ctmul.o \
+  entropy_cpu_stubs.o
+
+libmirage_crypto_xen_stubs.a: $(OBJS)
+	$(AR) r $@ $^
+endif
+
+clean:
+	$(RM) $(OBJS) libmirage_crypto_xen_stubs.a

xen/dune

@@ -1,21 +1,16 @@
-(copy_files# ../src/native/*)
-
-(library
- (name mirage_crypto_xen)
- (public_name mirage-crypto.xen)
- (optional)
- (libraries mirage-xen-posix)
- (foreign_stubs
-  (language c)
-  (names detect_cpu_features misc misc_sse hash_stubs md5 sha1 sha256 sha512
-    aes_generic aes_aesni des_generic chacha poly1305-donna ghash_pclmul
-    ghash_generic ghash_ctmul entropy_cpu_stubs)
-  (flags
-   (:standard)
-   (:include ../src/cflags.sexp)
-   (:include cflags-xen.sexp))))
+(copy_files#
+ (alias install)
+ (files ../src/native/*))
 
 (rule
- (with-stdout-to
-  cflags-xen.sexp
-  (run ./cflags.sh)))
+ (deps ../src/cflags.sexp Makefile)
+ (targets libmirage_crypto_xen_stubs.a)
+ (action
+  (no-infer
+   (progn
+    (run %{make})))))
+
+(install
+ (package mirage-crypto)
+ (section lib)
+ (files libmirage_crypto_xen_stubs.a))