Filter out warning as error options during preprocessing

4 files changed, 59 insertions, 43 deletions

diff --git a/build2/cc/compile.cxx b/build2/cc/compile.cxx
index c703a8a..9fae3c6 100644
--- a/build2/cc/compile.cxx
+++ b/build2/cc/compile.cxx
@@ -1714,8 +1714,13 @@ namespace build2
           // is to remove the -fmodules-ts option when preprocessing. Hopefully
           // there will be a "pure modules" mode at some point.
           //
-          append_options (args, t, c_coptions);
-          append_options (args, t, x_coptions);
+
+          // Don't treat warnings as errors.
+          //
+          const char* werror (cid == compiler_id::msvc ? "/WX" : "-Werror");
+
+          append_options (args, t, c_coptions, werror);
+          append_options (args, t, x_coptions, werror);
           append_options (args, tstd,
                           tstd.size () -
                           (modules && cid == compiler_id::clang ? 1 : 0));
@@ -1775,15 +1780,8 @@ namespace build2
             // Clang's -M does not imply -w (disable warnings). We also don't
             // need them in the -MD case (see above) so disable for both.
             //
-            // For GCC we want warnings in -MD (see sense_diag) but we don't
-            // want then to be treated as errors.
-            //
-            switch (cid)
-            {
-            case compiler_id::clang: args.push_back ("-w");         break;
-            case compiler_id::gcc:   args.push_back ("-Wno-error"); break;
-            default:                                                break;
-            }
+            if (cid == compiler_id::clang)
+              args.push_back ("-w");
 
             // Previously we used '*' as a target name but it gets expanded to
             // the current directory file names by GCC (4.9) that comes with
@@ -2654,8 +2652,14 @@ namespace build2
           if (md.symexport)
             append_symexport_options (args, t);
 
-          append_options (args, t, c_coptions);
-          append_options (args, t, x_coptions);
+          // Make sure we don't fail because of warnings.
+          //
+          // @@ Can be both -WX and /WX.
+          //
+          const char* werror (cid == compiler_id::msvc ? "/WX" : "-Werror");
+
+          append_options (args, t, c_coptions, werror);
+          append_options (args, t, x_coptions, werror);
           append_options (args, tstd,
                           tstd.size () -
                           (modules && cid == compiler_id::clang ? 1 : 0));
diff --git a/build2/utility.cxx b/build2/utility.cxx
index b0325fb..36f8a4d 100644
--- a/build2/utility.cxx
+++ b/build2/utility.cxx
@@ -266,17 +266,17 @@ namespace build2
   const dir_path empty_dir_path;
 
   void
-  append_options (cstrings& args, const lookup& l)
+  append_options (cstrings& args, const lookup& l, const char* e)
   {
     if (l)
-      append_options (args, cast<strings> (l));
+      append_options (args, cast<strings> (l), e);
   }
 
   void
-  append_options (strings& args, const lookup& l)
+  append_options (strings& args, const lookup& l, const char* e)
   {
     if (l)
-      append_options (args, cast<strings> (l));
+      append_options (args, cast<strings> (l), e);
   }
 
   void
@@ -287,26 +287,32 @@ namespace build2
   }
 
   void
-  append_options (cstrings& args, const strings& sv, size_t n)
+  append_options (cstrings& args, const strings& sv, size_t n, const char* e)
   {
     if (n != 0)
     {
       args.reserve (args.size () + n);
 
       for (size_t i (0); i != n; ++i)
-        args.push_back (sv[i].c_str ());
+      {
+        if (e == nullptr || e != sv[i])
+          args.push_back (sv[i].c_str ());
+      }
     }
   }
 
   void
-  append_options (strings& args, const strings& sv, size_t n)
+  append_options (strings& args, const strings& sv, size_t n, const char* e)
   {
     if (n != 0)
     {
       args.reserve (args.size () + n);
 
       for (size_t i (0); i != n; ++i)
-        args.push_back (sv[i]);
+      {
+        if (e == nullptr || e != sv[i])
+          args.push_back (sv[i]);
+      }
     }
   }
 
diff --git a/build2/utility.hxx b/build2/utility.hxx
index f6f9fe9..b057add 100644
--- a/build2/utility.hxx
+++ b/build2/utility.hxx
@@ -277,23 +277,25 @@ namespace build2
   // Append all the values from a variable to the C-string list. T is either
   // target or scope. The variable is expected to be of type strings.
   //
+  // If excl is not NULL, then filter this option out (note: case sensitive).
+  //
   struct variable;
 
   template <typename T>
   void
-  append_options (cstrings&, T&, const variable&);
+  append_options (cstrings&, T&, const variable&, const char* excl = nullptr);
 
   template <typename T>
   void
-  append_options (cstrings&, T&, const char*);
+  append_options (cstrings&, T&, const char*, const char* excl = nullptr);
 
   template <typename T>
   void
-  append_options (strings&, T&, const variable&);
+  append_options (strings&, T&, const variable&, const char* excl = nullptr);
 
   template <typename T>
   void
-  append_options (strings&, T&, const char*);
+  append_options (strings&, T&, const char*, const char* excl = nullptr);
 
   template <typename T>
   void
@@ -309,28 +311,32 @@ namespace build2
   struct lookup;
 
   void
-  append_options (cstrings&, const lookup&);
+  append_options (cstrings&, const lookup&, const char* excl = nullptr);
 
   void
-  append_options (strings&, const lookup&);
+  append_options (strings&, const lookup&, const char* excl = nullptr);
 
   void
   hash_options (sha256&, const lookup&);
 
   void
-  append_options (cstrings&, const strings&);
+  append_options (cstrings&, const strings&, const char* excl = nullptr);
 
   void
-  append_options (strings&, const strings&);
+  append_options (strings&, const strings&, const char* excl = nullptr);
 
   void
   hash_options (sha256&, const strings&);
 
   void
-  append_options (cstrings&, const strings&, size_t);
+  append_options (cstrings&,
+                  const strings&, size_t,
+                  const char* excl = nullptr);
 
   void
-  append_options (strings&, const strings&, size_t);
+  append_options (strings&,
+                  const strings&, size_t,
+                  const char* excl = nullptr);
 
   void
   hash_options (sha256&, const strings&, size_t);
diff --git a/build2/utility.ixx b/build2/utility.ixx
index 7a706f8..0622e99 100644
--- a/build2/utility.ixx
+++ b/build2/utility.ixx
@@ -35,16 +35,16 @@ namespace build2
 
   template <typename T>
   inline void
-  append_options (cstrings& args, T& s, const variable& var)
+  append_options (cstrings& args, T& s, const variable& var, const char* e)
   {
-    append_options (args, s[var]);
+    append_options (args, s[var], e);
   }
 
   template <typename T>
   inline void
-  append_options (strings& args, T& s, const variable& var)
+  append_options (strings& args, T& s, const variable& var, const char* e)
   {
-    append_options (args, s[var]);
+    append_options (args, s[var], e);
   }
 
   template <typename T>
@@ -56,16 +56,16 @@ namespace build2
 
   template <typename T>
   inline void
-  append_options (cstrings& args, T& s, const char* var)
+  append_options (cstrings& args, T& s, const char* var, const char* e)
   {
-    append_options (args, s[var]);
+    append_options (args, s[var], e);
   }
 
   template <typename T>
   inline void
-  append_options (strings& args, T& s, const char* var)
+  append_options (strings& args, T& s, const char* var, const char* e)
   {
-    append_options (args, s[var]);
+    append_options (args, s[var], e);
   }
 
   template <typename T>
@@ -76,17 +76,17 @@ namespace build2
   }
 
   inline void
-  append_options (cstrings& args, const strings& sv)
+  append_options (cstrings& args, const strings& sv, const char* e)
   {
     if (size_t n = sv.size ())
-      append_options (args, sv, n);
+      append_options (args, sv, n, e);
   }
 
   inline void
-  append_options (strings& args, const strings& sv)
+  append_options (strings& args, const strings& sv, const char* e)
   {
     if (size_t n = sv.size ())
-      append_options (args, sv, n);
+      append_options (args, sv, n, e);
   }
 
   inline void