Add support for rule-specific variables, use to fix cc.type data race

3 files changed, 16 insertions, 11 deletions

diff --git a/build2/cc/common.cxx b/build2/cc/common.cxx
index ae125a5..a1a17f7 100644
--- a/build2/cc/common.cxx
+++ b/build2/cc/common.cxx
@@ -80,9 +80,10 @@ namespace build2
 
       // See what type of library this is (C, C++, etc). Use it do decide
       // which x.libs variable name to use. If it's unknown, then we only
-      // look into prerequisites.
+      // look into prerequisites. Note: lookup starting from rule-specific
+      // variables (target should already be matched).
       //
-      const string* t (cast_null<string> (l.vars[c_type]));
+      const string* t (cast_null<string> (l.state[a][c_type]));
 
       bool impl (proc_impl && proc_impl (l, la));
       bool cc (false), same (false);
diff --git a/build2/cc/init.cxx b/build2/cc/init.cxx
index 2f88542..bb0269c 100644
--- a/build2/cc/init.cxx
+++ b/build2/cc/init.cxx
@@ -78,6 +78,8 @@ namespace build2
       //
       auto& v (var_pool.rw (rs));
 
+      auto v_t (variable_visibility::target);
+
       v.insert<strings> ("config.cc.poptions", true);
       v.insert<strings> ("config.cc.coptions", true);
       v.insert<strings> ("config.cc.loptions", true);
@@ -106,24 +108,26 @@ namespace build2
       v.insert<string> ("cc.stdlib");
 
       // Target type, for example, "C library" or "C++ library". Should be set
-      // on the target by the matching rule to the name of the module (e.g.,
-      // "c", "cxx"). Currenly only set for libraries and is used to decide
-      // which *.libs to use during static linking.
+      // on the target as a rule-specific variable by the matching rule to the
+      // name of the module (e.g., "c", "cxx"). Currenly only set for
+      // libraries and is used to decide which *.libs to use during static
+      // linking.
       //
       // It can also be the special "cc" value which means a C-common library
-      // but specific language is not known. Used in import installed logic.
+      // but specific language is not known. Used in the import installed
+      // logic.
       //
-      v.insert<string> ("cc.type");
+      v.insert<string> ("cc.type", v_t);
 
       // If set and is true, then this (imported) library has been found in a
       // system library search directory.
       //
-      v.insert<bool> ("cc.system");
+      v.insert<bool> ("cc.system", v_t);
 
       // C++ module name. Should be set on the bmi*{} target by the matching
       // rule.
       //
-      v.insert<string> ("cc.module_name");
+      v.insert<string> ("cc.module_name", v_t);
 
       // Ability to disable using preprocessed output for compilation.
       //
diff --git a/build2/cc/link-rule.cxx b/build2/cc/link-rule.cxx
index 230fc6f..ba6a22d 100644
--- a/build2/cc/link-rule.cxx
+++ b/build2/cc/link-rule.cxx
@@ -356,10 +356,10 @@ namespace build2
       otype ot (lt.type);
       linfo li (link_info (bs, ot));
 
-      // Set the library type (C, C++, etc).
+      // Set the library type (C, C++, etc) as rule-specific variable.
       //
       if (lt.library ())
-        t.vars.assign (c_type) = string (x);
+        t.state[a].assign (c_type) = string (x);
 
       bool binless (lt.library ()); // Binary-less until proven otherwise.