Improve diagnostics when c-family modules using different toolchains

We now also warn on toolchain pattern mismatch.

6 files changed, 50 insertions, 20 deletions

diff --git a/build2/c/init.cxx b/build2/c/init.cxx
index 3ab91d4..bc97266 100644
--- a/build2/c/init.cxx
+++ b/build2/c/init.cxx
@@ -202,6 +202,8 @@ namespace build2
         v.insert<string>   ("c.signature"),
         v.insert<string>   ("c.checksum"),
 
+        v.insert<string>   ("c.pattern"),
+
         v.insert<target_triplet> ("c.target"),
 
         v.insert<string>   ("c.target.cpu"),
diff --git a/build2/cc/common.hxx b/build2/cc/common.hxx
index ad550e1..f4cd0c7 100644
--- a/build2/cc/common.hxx
+++ b/build2/cc/common.hxx
@@ -94,6 +94,8 @@ namespace build2
       const variable& x_signature;
       const variable& x_checksum;
 
+      const variable& x_pattern;
+
       const variable& x_target;
       const variable& x_target_cpu;
       const variable& x_target_vendor;
diff --git a/build2/cc/guess.hxx b/build2/cc/guess.hxx
index 2eaa9d7..e3a4d8c 100644
--- a/build2/cc/guess.hxx
+++ b/build2/cc/guess.hxx
@@ -133,7 +133,7 @@ namespace build2
     // unlike all the preceding fields, this one takes into account the
     // compile options (e.g., -m32).
     //
-    // The cc_pattern is the toolchain program pattern that could sometimes be
+    // The pattern is the toolchain program pattern that could sometimes be
     // derived for some toolchains. For example, i686-w64-mingw32-*-4.9.
     //
     // The bin_pattern is the binutils program pattern that could sometimes be
@@ -151,7 +151,7 @@ namespace build2
       string signature;
       string checksum;
       string target;
-      string cc_pattern;
+      string pattern;
       string bin_pattern;
     };
 
diff --git a/build2/cc/init.cxx b/build2/cc/init.cxx
index 90821ae..7a3e99e 100644
--- a/build2/cc/init.cxx
+++ b/build2/cc/init.cxx
@@ -96,6 +96,7 @@ namespace build2
       // Hint variables (not overridable).
       //
       v.insert<string>         ("config.cc.id");
+      v.insert<string>         ("config.cc.hinter"); // Hinting module.
       v.insert<string>         ("config.cc.pattern");
       v.insert<target_triplet> ("config.cc.target");
 
@@ -156,12 +157,14 @@ namespace build2
       if (!cast_false<bool> (rs["cc.core.vars.loaded"]))
         load_module (rs, rs, "cc.core.vars", loc);
 
-      // config.cc.id
+      // config.cc.{id,hinter}
       //
       {
-        // This value must be hinted.
+        // These values must be hinted.
         //
         rs.assign<string> ("cc.id") = cast<string> (hints["config.cc.id"]);
+        rs.assign<string> ("cc.hinter") =
+          cast<string> (hints["config.cc.hinter"]);
       }
 
       // config.cc.target
@@ -188,8 +191,8 @@ namespace build2
       {
         // This value could be hinted.
         //
-        if (auto l = hints["config.cc.pattern"])
-          rs.assign<string> ("cc.pattern") = cast<string> (l);
+        rs.assign<string> ("cc.pattern") =
+          cast_empty<string> (hints["config.cc.pattern"]);
       }
 
       return true;
diff --git a/build2/cc/module.cxx b/build2/cc/module.cxx
index 74238c3..d806583 100644
--- a/build2/cc/module.cxx
+++ b/build2/cc/module.cxx
@@ -167,6 +167,8 @@ namespace build2
 
       rs.assign (x_target) = move (tt);
 
+      rs.assign (x_pattern) = ci.pattern;
+
       new_ = p.second;
 
       // Load cc.core.guess.
@@ -180,10 +182,11 @@ namespace build2
         // Note that all these variables have already been registered.
         //
         h.assign ("config.cc.id") = cast<string> (rs[x_id]);
+        h.assign ("config.cc.hinter") = string (x);
         h.assign ("config.cc.target") = cast<target_triplet> (rs[x_target]);
 
-        if (!ci.cc_pattern.empty ())
-          h.assign ("config.cc.pattern") = ci.cc_pattern;
+        if (!ci.pattern.empty ())
+          h.assign ("config.cc.pattern") = ci.pattern;
 
         load_module (rs, rs, "cc.core.guess", loc, false, h);
       }
@@ -193,18 +196,36 @@ namespace build2
         // matched ours since it could have been loaded by another c-family
         // module.
         //
-        // Note that we don't require that patterns match. Presumably, if the
-        // toolchain id and target are the same, then where exactly the tools
-        // come from doesn't really matter.
-        //
+        const auto& h (cast<string> (rs["cc.hinter"]));
+
         {
           const auto& cv (cast<string> (rs["cc.id"]));
           const auto& xv (cast<string> (rs[x_id]));
 
           if (cv != xv)
-            fail (loc) << "cc and " << x << " module toolchain mismatch" <<
-              info << "cc.id is " << cv <<
-              info << x_id.name << " is " << xv;
+            fail (loc) << h << " and " << x << " module toolchain mismatch" <<
+              info << h << " is " << cv <<
+              info << x << " is " << xv <<
+              info << "consider explicitly specifying config." << h
+                       << " and config." << x;
+        }
+
+        // We used to not require that patterns match assuming that if the
+        // toolchain id and target are the same, then where exactly the tools
+        // come from doesn't really matter. But in most cases it will be the
+        // g++-7 vs gcc kind of mistakes. So now we warn since even if
+        // intentional, it is still a bad idea.
+        //
+        {
+          const auto& cv (cast<string> (rs["cc.pattern"]));
+          const auto& xv (cast<string> (rs[x_pattern]));
+
+          if (cv != xv)
+            warn (loc) << h << " and " << x << " toolchain pattern mismatch" <<
+              info << h << " is '" << cv << "'" <<
+              info << x << " is '" << xv << "'" <<
+              info << "consider explicitly specifying config." << h
+                       << " and config." << x;
         }
 
         {
@@ -212,9 +233,9 @@ namespace build2
           const auto& xv (cast<target_triplet> (rs[x_target]));
 
           if (cv != xv)
-            fail (loc) << "cc and " << x << " module target mismatch" <<
-              info << "cc.target is " << cv <<
-              info << x_target.name << " is " << xv;
+            fail (loc) << h << " and " << x << " module target mismatch" <<
+              info << h << " target is " << cv <<
+              info << x << " target is " << xv;
         }
       }
     }
@@ -326,9 +347,9 @@ namespace build2
           for (const string& o: tstd) dr << ' ' << o;
         }
 
-        if (!ci.cc_pattern.empty ()) // bin_pattern printed by bin
+        if (!ci.pattern.empty ()) // Note: bin_pattern printed by bin
         {
-          dr << "\n  pattern    " << ci.cc_pattern;
+          dr << "\n  pattern    " << ci.pattern;
         }
 
         if (verb >= 3 && !inc_dirs.empty ())
diff --git a/build2/cxx/init.cxx b/build2/cxx/init.cxx
index ea3bf79..5eefa53 100644
--- a/build2/cxx/init.cxx
+++ b/build2/cxx/init.cxx
@@ -397,6 +397,8 @@ namespace build2
         v.insert<string>   ("cxx.signature"),
         v.insert<string>   ("cxx.checksum"),
 
+        v.insert<string>   ("cxx.pattern"),
+
         v.insert<target_triplet> ("cxx.target"),
 
         v.insert<string>   ("cxx.target.cpu"),