Allow to override flavor

lib/Driver.ml

@@ -428,7 +428,12 @@ let detect_cc () =
     KPrint.bprintf "%scc is:%s %s%s\n" Ansi.underline Ansi.reset !cc real
   end;
 
-  cc_flavor := detect_compiler_flavor !cc;
+  begin
+    match !Options.cc_flavor with
+    | Some f -> cc_flavor := f
+    | None ->   cc_flavor := detect_compiler_flavor !cc
+  end;
+
   if not !Options.silent then
     KPrint.bprintf "%scc flavor is:%s %s\n" Ansi.underline Ansi.reset
       (Options.string_of_compiler_flavor !cc_flavor);

lib/Options.ml

@@ -17,6 +17,14 @@ let string_of_compiler_flavor = function
   | Compcert -> "compcert"
   | MSVC -> "msvc"
 
+let compiler_flavor_of_string = function
+  | "generic" -> Generic
+  | "gcc" -> GCC
+  | "clang" -> Clang
+  | "compcert" -> Compcert
+  | "msvc" -> MSVC
+  | s -> failwith ("unrecognized compiler flavor: " ^ s)
+
 let pinc b = function
   | All -> Buffer.add_string b "*"
   | HeaderOnly h -> Buffer.add_string b h; Buffer.add_string b ".h"
@@ -43,6 +51,7 @@ let verbose = ref false
 let silent = ref false
 let exe_name = ref ""
 let cc = ref ""
+let cc_flavor : compiler_flavor option ref = ref None
 let m32 = ref false
 let fsopts: string list ref = ref []
 let ccopts: string list ref = ref []

src/Karamel.ml

@@ -191,8 +191,13 @@ Supported options:|}
     (* KaRaMeL as a driver *)
     "-fstar", Arg.Set_string Options.fstar, " fstar.exe to use; defaults to \
       'fstar.exe'";
-    "-cc", Arg.Set_string Options.cc, " compiler to use; one of gcc (default), \
-      compcert, g++, clang, msvc";
+    "-cc", Arg.Set_string Options.cc, " compiler to use; default is 'cc'. \
+      you can also set the CC environment variable";
+    "-ccflavor", Arg.String (fun s ->
+        let flav = Options.compiler_flavor_of_string s in
+        Options.cc_flavor := Some flav), " C compiler flavor. This is \
+      normally autodetected. It can be set to 'gcc', 'clang', 'compcert', 'msvc' \
+      or 'generic'";
     "-m32", Arg.Set Options.m32, " turn on 32-bit cross-compiling";
     "-fsopt", Arg.String (prepend Options.fsopts), " option to pass to F* (use \
       -fsopts to pass a comma-separated list of values)";